Reflective heat-insulation coating as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of automobile coatings, and discloses a reflective heat-insulating coating as well as a preparation method and application thereof. The reflective heat-insulation coating provided by the invention comprises modified acrylic resin, reflective heat-insulation filler and an ultraviolet light absorber according to a specific mass ratio, and optional auxiliaries such as pigment and a defoaming agent. The modified acrylic resin can form a strong combination effect with hollow glass beads and titanium dioxide in the reflective heat insulation filler through multiple modes such as non-covalent combination, space winding and physical barrier, and has excellent compatibility with other components in the coating; according to the present invention, the compactness of the film layer obtained after the reflective thermal insulation coating film forming and the adhesion with the cold-rolled steel sheet surface are effectively improved, and the film layer has advantages of excellent reflective thermal insulation effect, excellent durability and excellent salt spray resistance, can well meet the requirements of automobiles in the long-term use process, and has excellent application prospects.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of automobile coatings, and particularly relates to a reflective heat-insulating coating as well as a preparation method and application thereof. BACKGROUND

[0002] With the increasing number of automobiles, the energy consumption and comfort level of automobiles during use have become the focus of attention. In summer, the surface temperature of the automobile body will rapidly rise when exposed to sunlight for a long time, which not only increases the energy consumption of the air conditioner in the car, but also accelerates the aging of automobile components. The traditional automobile coatings mainly focus on decoration and protection, and have poor performance in terms of reflection and heat insulation. Some existing heat-insulating coatings have certain heat-insulating effects, but have problems such as unsatisfactory heat-insulating effect, poor adhesion to the surface of the automobile, and insufficient durability, and cannot meet the needs of automobiles during long-term use.

[0003] Therefore, it is of great significance to develop an automobile coating with good reflective heat-insulating effect, strong adhesion to the surface of the automobile, and good durability. SUMMARY

[0004] A first object of the present application is to provide a reflective heat-insulating coating with strong adhesion to the surface of commonly used automobile panels such as cold-rolled steel sheets, and the film obtained after film formation has excellent reflective heat-insulating effect, durability, and salt spray resistance, and can well meet the needs of automobiles during long-term use, and has excellent application prospects.

[0005] A second object of the present application is to provide a preparation method of the above-mentioned reflective heat-insulating coating.

[0006] A third object of the present application is to provide application of the above-mentioned reflective heat-insulating coating in the field of automobiles.

[0007] Specifically, the reflective heat-insulating coating provided by the present application comprises modified acrylic resin, reflective heat-insulating filler, ultraviolet absorber, and optional pigments, dispersants, defoamers, leveling agents, and thickening agents in a weight ratio of (10-50):(5-20):(0.1-2):(0-15):(0-10):(0-5):(0-4):(0-4); wherein the modified acrylic resin is prepared by modification reaction of nanometer titanium dioxide, silane coupling agent, and acrylic resin; and the reflective heat-insulating coating comprises hollow glass microspheres and titanium dioxide in a weight ratio of (3-5):1.

[0008] Further, in the preparation of the modified acrylic resin, the crystal form of the nanometer titanium dioxide is anatase and / or rutile.

[0009] Furthermore, in the preparation of the modified acrylic resin, the particle size of the nano-titanium dioxide is 10nm~50nm.

[0010] Furthermore, in the preparation of the modified acrylic resin, the silane coupling agent includes one or more of γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and vinyltrimethoxysilane.

[0011] Furthermore, in the preparation of the modified acrylic resin, the hydroxyl content of the acrylic resin is 2%~8%, and the viscosity is 2000mPa·s~8000mPa·s.

[0012] Furthermore, in the preparation of the modified acrylic resin, the weight ratio of the nano-titanium dioxide, silane coupling agent and acrylic resin is (10~15):(5~8):100.

[0013] Furthermore, in the preparation of the modified acrylic resin, the temperature of the modification reaction is 60℃~80℃, and the time is 3h~5h.

[0014] Furthermore, in the reflective heat-insulating filler, the hollow glass microspheres have a particle size of 10μm~50μm and an actual density of 0.1g / cm³. 3 ~0.5g / cm 3 .

[0015] Furthermore, in the reflective heat-insulating filler, the titanium dioxide has anatase and / or rutile crystal forms.

[0016] Further, the reflective heat-insulating coating comprises a modified acrylic resin, reflective heat-insulating filler, ultraviolet absorber, pigment, dispersant, defoamer, leveling agent, thickener and solvent in a weight ratio of (20~30):(10~15):(0.5~1):(5~10):(3~5):(2~3):(1~2):(1~2):(30~60).

[0017] Furthermore, the ultraviolet absorber is selected from one or more of salicylates, benzophenones, benzotriazoles, and triazines.

[0018] Furthermore, the pigment is selected from one or more of iron oxide red, titanium dioxide, iron black, chrome yellow, and iron blue.

[0019] Furthermore, the dispersant is selected from one or more of inorganic dispersants, small molecule dispersants, polymeric dispersants, and composite dispersants.

[0020] Furthermore, the defoamer is selected from one or more of silicone defoamers, polyether defoamers, and polyether-modified silicone defoamers.

[0021] Furthermore, the leveling agent is selected from one or more of polyether-modified polysiloxane leveling agents, acrylate leveling agents, fluorocarbon compound leveling agents, and polyether leveling agents.

[0022] Furthermore, the thickener is selected from one or more of cellulose ether thickeners, alkali-swellable thickeners, and polyurethane thickeners.

[0023] Furthermore, the solvent comprises an organic solvent and water in a volume ratio of (1~2):1, wherein the organic solvent is toluene and / or xylene.

[0024] Furthermore, based on the total weight of the reflective heat-insulating coating, the modified acrylic resin content is 20wt%~30wt%, the reflective heat-insulating filler content is 10wt%~15wt%, the ultraviolet absorber content is 0.5wt%~1wt%, the pigment content is 5wt%~10wt%, the dispersant content is 3wt%~5wt%, the defoamer content is 2wt%~3wt%, the leveling agent content is 1wt%~2wt%, the thickener content is 1wt%~2wt%, and the solvent content is 35wt%~57.5wt%.

[0025] The preparation method of the above-mentioned reflective heat-insulating coating provided by the present invention includes: taking the reflective heat-insulating filler and optionally pigments and dispersants and solvent for mixing treatment I to obtain a pre-dispersion liquid; taking the pre-dispersion liquid for grinding treatment to obtain a grinding liquid; taking the grinding liquid, modified acrylic resin, ultraviolet absorber and optionally defoamer, leveling agent, thickener and solvent for mixing treatment II to obtain the reflective heat-insulating coating.

[0026] Furthermore, the stirring speed of the mixing process I is 800 r / min to 1200 r / min, and the time is 30 min to 60 min.

[0027] Furthermore, the target fineness of the grinding process is no greater than 50 μm.

[0028] Furthermore, the stirring speed of the mixing treatment II is 400 r / min to 600 r / min, and the time is 60 min to 90 min.

[0029] This invention provides the application of the above-mentioned reflective heat-insulating coating in the automotive field.

[0030] The method of using the above-mentioned reflective heat-insulating coating provided by the present invention includes: taking the reflective heat-insulating coating onto the surface of the object to be covered to form a wet layer, and performing a film-forming treatment to form a dry film; wherein, the temperature of the film-forming treatment is 120℃~150℃, and the time is 10min~60min.

[0031] Beneficial effects: The reflective heat-insulating coating provided by this invention comprises a modified acrylic resin, a reflective heat-insulating filler, an ultraviolet absorber, and optional pigments, defoamers, and other additives in a specific mass ratio. The modified acrylic resin is obtained by modifying it with nano-titanium dioxide and a silane coupling agent. Nano-titanium dioxide particles are introduced into the molecular chain through titanium-oxygen and silicon-oxygen bonds, enabling it to form a strong bond with the hollow glass microspheres and titanium dioxide in the reflective heat-insulating filler through multiple mechanisms such as non-covalent bonding, spatial entanglement, and physical barrier. The modified acrylic resin exhibits excellent compatibility with other components in the coating. Through the synergistic effect of the components, the density of the film obtained after the reflective heat-insulating coating is effectively improved, as well as its adhesion to the surface of cold-rolled steel sheets. Furthermore, the film exhibits excellent reflective heat-insulating effect, durability, and salt spray resistance, which can well meet the needs of automobiles during long-term use and has excellent application prospects. Detailed Implementation

[0032] The reflective heat-insulating coating provided by this invention specifically includes modified acrylic resin, reflective heat-insulating filler, ultraviolet absorber, and optional pigments, dispersants, defoamers, leveling agents, and thickeners. The modified acrylic resin is prepared by reacting nano-titanium dioxide, a silane coupling agent, and acrylic resin. The reflective heat-insulating filler includes hollow glass microspheres and titanium dioxide, and the weight ratio of hollow glass microspheres to titanium dioxide is specifically (3~5):1, specifically 3:1, 3.1:1, 3.3:1, 3.5:1, 3.8:1, 4:1, 4.3:1, 4.8:1, 5:1, or any value between them.

[0033] In this invention, the modified acrylic resin, compared to acrylic resin, introduces nano-titanium dioxide particles into the molecular chain through titanium-oxygen bonds and silicon-oxygen bonds. Through multiple mechanisms such as non-covalent bonding, spatial entanglement, and physical barrier, it forms a strong bond with the hollow glass microspheres and titanium dioxide in the reflective heat-insulating filler. This enables the formation of a high-density film layer on the surface of cold-rolled steel sheets and other materials. This film layer has strong adhesion to cold-rolled steel sheets and other materials, and also has excellent reflective heat insulation effect, durability, and salt spray resistance. It has a very promising application prospect in the preparation of reflective heat-insulating automotive coatings.

[0034] In this invention, the weight ratio of the modified acrylic resin to the reflective heat-insulating filler is (10~50):(5~20), specifically it can be 10:5, 10:8, 11:5, 15:11, 25:17, 30:19, 50:20 or any value between them. The weight ratio of the modified acrylic resin to the ultraviolet absorber is (10~50):(0.1~2), specifically it can be 10:0.1, 12:0.3, 15:0.38, 20:0.1, 25:1, 30:1, 40:2, 50:2 or any value between them. The weight ratio of the pigment to the modified acrylic resin is (0~15):(10~50), specifically it can be 0, 1:10, 1:50, 2:11, 3:14, 5:20, 9:40, 15:50 or any value between them. The weight ratio of the dispersant to the modified acrylic resin is (0~10):(10~50), specifically it can be 0, 0.1:10, 0.1:50, 1:10, 2:19, 3:40, 10:50 or any value between them. The weight ratio of the defoamer to the modified acrylic resin is (0~5):(10~50), specifically it can be 0, 0.1:10, 0.5:14, 1:15, 2:29, 3:35, 4:50, 5:50 or any value between them. The weight ratio of the leveling agent to the modified acrylic resin is (0~4):(10~50), specifically it can be 0, 1:10, 1:20, 3:40, 4:50 or any value between them. The weight ratio of the thickener to the modified acrylic resin is (0~4):(10~50), specifically it can be 0, 1:10, 2:19, 3:40, 4:50 or any value between them.

[0035] In some specific embodiments, the reflective heat-insulating coating preferably comprises a modified acrylic resin, reflective heat-insulating filler, ultraviolet absorber, pigment, dispersant, defoamer, leveling agent, thickener, and solvent in a weight ratio of (20~30):(10~15):(0.5~1):(5~10):(3~5):(2~3):(1~2):(1~2):(30~60). Specifically, the solvent is prepared by mixing an organic solvent and water, and specific examples of the organic solvent include, but are not limited to, toluene and / or xylene. More specifically, the volume ratio of the organic solvent to water is preferably (1~2):1, specifically 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, or any value between them.

[0036] In some preferred embodiments, the content of the modified acrylic resin is preferably 20wt% to 30wt%, specifically 20wt%, 21.5wt%, 22wt%, 23wt%, 25wt%, 28wt%, 30wt%, or any value between them; the content of the reflective heat-insulating filler is preferably 10wt% to 15wt%, specifically 10wt%, 11wt%, 12.5wt%, 13wt%, 14wt%, 15wt%, or any value between them; the content of the ultraviolet absorber is preferably 0.5wt%. The content of the pigment is preferably 5wt% to 1wt%, specifically 5wt%, 5.3wt%, 5.8wt%, 6wt%, 6.5wt%, 7wt%, 8wt%, 9wt%, 10wt%, or any value between them; the content of the dispersant is preferably 3wt% to 5wt%, specifically 3wt%, 3.2wt%, 3.5wt%. The defoamer content is preferably 2wt% to 3wt%, specifically 2wt%, 2.05wt%, 2.1wt%, 2.2wt%, 2.4wt%, 2.5wt%, 2.7wt%, 2.9wt%, 3wt%, or any value between them; the leveling agent content is preferably 1wt% to 2wt%, specifically 1wt%, 1.05wt%, 1.2wt%, 1. The content of the thickener is preferably 1 wt% to 2 wt%, specifically 1 wt%, 1.1 wt%, 1.3 wt%, 1.5 wt%, 1.8 wt%, 2 wt%, or any value between them; the content of the solvent is 35 wt% to 57.5 wt%, specifically 35 wt%, 38 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 57.5 wt%, or any value between them.

[0037] In some specific embodiments, the modified acrylic resin is preferably prepared by the following method: nano-titanium dioxide, a silane coupling agent, and acrylic resin are mixed and subjected to a modification reaction to obtain the modified acrylic resin. The weight ratio of the nano-titanium dioxide, silane coupling agent, and acrylic resin is preferably (10~15):(5~8):100, specifically 10:5:100, 11:6:100, 13:7:100, 15:8:10, or any value between them. The modification reaction conditions specifically include a temperature preferably of 60℃~80℃, specifically 60℃, 63℃, 65℃, 68℃, 70℃, 75℃, 78℃, 80℃, or any value between them; and a time preferably of 3h~5h, specifically 3h, 3.1h, 3.3h, 3.5h, 4h, 4.2h, 4.8h, 5h, or any value between them.

[0038] In the preparation of the modified acrylic resin, the nano-titanium dioxide refers to titanium dioxide particles with nanoscale dimensions, rich in hydroxyl groups on the surface, and highly polar. More specifically, the crystal form of the nano-titanium dioxide can be anatase and / or rutile.

[0039] In some preferred embodiments, the nano-titanium dioxide is preferably anatase. The nano-titanium dioxide has characteristics such as high surface hydroxyl density, loose crystal structure, and numerous lattice defects, which enables better modification of acrylic resin, thereby imparting the resulting reflective heat-insulating coating with superior reflective heat-insulating effect, durability, and salt spray resistance.

[0040] In the preparation of the modified acrylic resin, the silane coupling agent refers to an organosilicon monomer with two or more different reactive groups in its structure, which can bond with organic and inorganic materials. Specific examples include, but are not limited to, one or more of the following: γ-aminopropyltriethoxysilane (silane coupling agent KH-550), γ-methacryloyloxypropyltrimethoxysilane (silane coupling agent KH-570), N-(β-aminoethyl)-γ-aminopropyltriethoxysilane (silane coupling agent KH-791), γ-(2,3-epoxypropoxy)propyltrimethoxysilane (silane coupling agent KH-560), and vinyltrimethoxysilane (silane coupling agent A-171).

[0041] In the process of preparing the modified acrylic resin, the acrylic resin refers to a type of copolymer obtained by polymerization of acrylate, methacrylate and ethylene monomers such as styrene. Those skilled in the art can make adaptive selections according to actual needs, and the present invention does not impose any particular limitations.

[0042] In some preferred embodiments, the hydroxyl content of the acrylic resin is preferably 2% to 8%, specifically 2%, 3%, 4%, 5%, 6%, 7%, 8%, or any value between them; the viscosity is preferably 2000 mPa·s to 8000 mPa·s, specifically 2000 mPa·s, 2500 mPa·s, 3000 mPa·s, 4000 mPa·s, 5000 mPa·s, 6000 mPa·s, 7000 mPa·s, 8000 mPa·s, or any value between them.

[0043] In this invention, the hollow glass microspheres in the reflective heat insulation filler refer to a type of lightweight, hollow inorganic microsphere material made from glass raw materials such as borosilicates. They work synergistically with modified acrylic resin and titanium dioxide to give the reflective heat insulation coating excellent reflective heat insulation effect, durability and salt spray resistance.

[0044] In some specific embodiments, the particle size of the hollow glass microspheres is preferably 10μm to 50μm, specifically 20μm, 25μm, 30μm, 40μm, 45μm, 50μm, or any value between them; the actual density is preferably 0.1g / cm³. 3 ~0.5g / cm 3 Specifically, it could be 0.1 g / cm³. 3 0.18g / cm 3 0.22g / cm 3 0.28g / cm 3 0.32g / cm 3 0.38g / cm 3 0.42g / cm 3 Or any value between them.

[0045] In this invention, the titanium dioxide in the reflective heat-insulating filler can specifically be anatase and / or rutile. In some preferred embodiments, the titanium dioxide is preferably rutile. In this case, the rutile titanium dioxide has superior ultraviolet shielding efficiency and stability, thus imparting to the resulting reflective heat-insulating coating superior reflective heat insulation effect, durability, and salt spray resistance.

[0046] In this invention, the ultraviolet absorber is used to selectively absorb ultraviolet light to reduce the damage of ultraviolet light to chemical structures. Specific examples include, but are not limited to, one or more of salicylate ultraviolet absorbers, benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, and triazine ultraviolet absorbers. In some specific embodiments, the ultraviolet absorber may specifically be a benzotriazole ultraviolet absorber purchased from BASF China Ltd., with the product number UV-327.

[0047] In this invention, the pigment is used to impart color to the reflective heat-insulating coating, and the type and source can be a variety of existing options, including, but not limited to, one or more of iron oxide red, titanium dioxide, iron black, chrome yellow and iron blue.

[0048] In this invention, the dispersant is used to improve the dispersibility of various substances in the reflective heat-insulating coating and the stability of the system. The type and source can be any of the existing options, specifically including, but not limited to, one or more of inorganic dispersants, small molecule dispersants, polymeric dispersants, and composite dispersants. The small molecule dispersant refers to a dispersing aid with small molecule compounds such as inorganic acid salts, organic acid salts, amines, and alkanolamines as its core component, achieving dispersion mainly through electrostatic repulsion and chelation. The polymeric dispersant refers to a dispersing aid with large polymer molecules with molecular weights between several thousand and tens of thousands as its core component, achieving dispersion mainly through steric hindrance or synergistic electrostatic repulsion. The composite dispersant refers to a mixed dispersant obtained by compounding multiple types of dispersants. In some specific embodiments, the dispersant may be a polymeric dispersant purchased from BYK Chemicals (Germany), specifically catalog number BYK-163.

[0049] In this invention, the defoamer is used to suppress or eliminate foam in reflective heat-insulating coatings. Its type and source can be any of the existing options, specifically including, but not limited to, one or more of: silicone defoamers, polyether defoamers, and polyether-modified silicone defoamers. Specifically, the silicone defoamer refers to a class of defoaming aids with silicone compounds as the core component. The polyether defoamer refers to a class of defoaming aids with polyether compounds as the core component. The polyether-modified silicone defoamer refers to a class of composite defoaming aids with polyether segment grafted modified silicone as the core component. In some specific embodiments, the defoamer may specifically be a silicone defoamer purchased from BYK Chemicals (Germany), specifically catalog number BYK-141.

[0050] In this invention, the leveling agent is used to improve the flowability and wetting properties of the reflective heat-insulating coating. The type and source can be any of the existing options, specifically including, but not limited to, one or more of the following: polyether-modified polysiloxane leveling agents, acrylate leveling agents, fluorocarbon compound leveling agents, and polyether leveling agents. Specifically, the polyether-modified polysiloxane leveling agent refers to a class of leveling aids with polyether-modified polysiloxane as the core component. The acrylate leveling agent refers to a class of leveling aids with acrylate polymers as the core component. The fluorocarbon compound leveling agent refers to a class of leveling aids with fluorinated compounds such as perfluoroalkyl, fluorinated acrylate, and fluorinated polysiloxane as the core component. The polyether leveling agent refers to a class of leveling aids with polyether polymers such as polyoxyethylene, polyoxypropylene block copolymers, and polyether ester copolymers as the core component. In some specific embodiments, the leveling agent may specifically be a polyether-modified polysiloxane leveling agent purchased from BYK Chemicals (Germany), specifically catalog number BYK-333.

[0051] In this invention, the thickener is used to increase the viscosity of the reflective heat-insulating coating. Its type and source can be any of the existing options, specifically including, but not limited to, polyurethane associative thickeners and / or alkali-swellable thickeners. The polyurethane associative thickener refers to a thickening agent with a polyurethane block copolymer containing hydrophilic polyether segments and hydrophobic ends as its core component, utilizing the association of the hydrophobic ends to form a reversible network, thus achieving a thickening effect. The alkali-swellable thickener refers to a thickening agent with an acrylic copolymer as its core component, utilizing the extension of the molecular chains after alkali neutralization to achieve a thickening effect. In some specific embodiments, the thickener may specifically be an alkali-swellable thickener purchased from Rohm and Haas China Ltd., specifically product number TT-935.

[0052] The preparation method of the reflective heat-insulating coating provided by the present invention includes: mixing the reflective heat-insulating filler, pigment, dispersant and a portion of solvent in a mixing treatment I to obtain a pre-dispersion liquid; grinding the pre-dispersion liquid to obtain a grinding liquid; and mixing the modified acrylic resin, defoamer, leveling agent, thickener, ultraviolet absorber and remaining solvent in a mixing treatment II to obtain the reflective heat-insulating coating. The mixing treatments I and II are not particularly limited and can be performed using various existing methods. The "I" and "II" in "mixing treatment I" and "mixing treatment II" are for ease of description and have no other special meaning. The grinding treatment is not particularly limited and can be performed using various existing methods to refine particles and break up agglomerates.

[0053] In some specific embodiments, the conditions for the mixing treatment I specifically include a stirring speed preferably of 800 r / min to 1200 r / min, specifically 800 r / min, 900 r / min, 100 r / min, 1100 r / min, 1200 r / min or any value between them; and a time preferably of 30 min to 60 min, specifically 30 min, 35 min, 40 min, 50 min, 55 min, 60 min or any value between them.

[0054] In some specific embodiments, the target fineness of the grinding process is preferably no greater than 50 μm, more preferably 20 μm to 40 μm, and can specifically be 20 μm, 25 μm, 30 μm, 35 μm, 40 μm or any value between them.

[0055] In some specific embodiments, the conditions for the mixing treatment II specifically include a stirring speed preferably of 400 r / min to 600 r / min, specifically 400 r / min, 420 r / min, 430 r / min, 460 r / min, 480 r / min, 500 r / min, 520 r / min, 550 r / min, 580 r / min, 600 r / min or any value between them; and a time preferably of 60 min to 90 min, specifically 60 min, 65 min, 70 min, 75 min, 80 min, 90 min or any value between them.

[0056] The present invention also provides the application of the above-mentioned reflective heat-insulating coating in the automotive field.

[0057] The method for using the above-mentioned reflective heat-insulating coating provided by the present invention specifically includes: applying the reflective heat-insulating coating to the surface of the object to be covered to form a wet layer, and performing a film-forming treatment to form a dry film. The method of applying the reflective heat-insulating coating to the surface of the object to be covered to form a wet layer is not particularly limited; various existing methods can be used to form the wet layer. Specific examples include, but are not limited to, one or more of the following methods: spraying, brushing, and roller coating. The method of film-forming treatment is not particularly limited; various existing methods can be used to form the film.

[0058] In some specific embodiments, the conditions for the film-forming treatment specifically include a temperature preferably of 120°C to 150°C, specifically 120°C, 123°C, 125°C, 130°C, 135°C, 140°C, 150°C or any value between them; and a time preferably of 10 min to 60 min, specifically 10 min, 12 min, 15 min, 18 min, 20 min, 30 min, 40 min, 50 min, 60 min or any value between them.

[0059] The embodiments of the present invention are described in detail below. These embodiments are intended to explain the present invention and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0060] The reagents and their sources involved in the following preparation examples and embodiments specifically include: Anatase nano-titanium dioxide (Hangzhou Wanjing New Materials Co., Ltd., product number VK-TA18); Rutile titanium dioxide I (Hangzhou Wanjing New Material Co., Ltd., product number VK-T25); Rutile titanium dioxide II (DuPont China Group Co., Ltd., product number R-902); Rutile titanium dioxide III (DuPont China Group Co., Ltd., product number R-706); Hollow glass microspheres I (Zhengzhou Shenglait Hollow Microsphere New Material Co., Ltd., item number HL30); Hollow glass microspheres II (Zhengzhou Shenglait Hollow Microsphere New Material Co., Ltd., item number HL20); Hollow glass microspheres III (Zhengzhou Shenglait Hollow Microsphere New Material Co., Ltd., item number HL40); γ-Methacryloxypropyltrimethoxysilane (Nanjing Shuguang Silane Chemical Co., Ltd., product number KH-570); Acrylic resin (Qingyuan Yake Chemical Co., Ltd., product number YZ-H755); Iron oxide red 101 (purchased from Jiangsu Yuxing Industry and Trade Co., Ltd.); Polymer dispersant (BYK-163, German BYK Chemicals); Organosilicon defoamer (BYK Chemicals, Germany, product number BYK-141); Polyether-modified polysiloxane leveling agent (BYK-333, German BYK Chemicals). Alkali-swellable thickener (Rohm and Haas China Ltd., product number TT-935); Benzotriazole UV absorber (BASF China Co., Ltd., product number UV-327).

[0061] Preparation Example 1 This preparation example illustrates the preparation of a modified acrylic resin, specifically comprising: taking 12 parts of anatase nano-titanium dioxide (particle size of 25 nm), 6 parts of γ-methacryloyloxypropyltrimethoxysilane, and 100 parts of acrylic resin (hydroxyl content of 4.5%, viscosity of 3000 mPa·s~5000 mPa·s / 25℃), mixing them evenly, and stirring and reacting at 70℃ for 4 h to obtain the modified acrylic resin.

[0062] Preparation Example 2 This preparation example illustrates the preparation of a modified acrylic resin, specifically including: taking 10 parts of anatase nano-titanium dioxide, 5 parts of silane coupling agent and 100 parts of acrylic resin, mixing them evenly, and stirring and reacting at 60°C for 3 hours to obtain the modified acrylic resin.

[0063] Preparation Example 3 This preparation example illustrates the preparation of a modified acrylic resin, specifically including: taking 15 parts of anatase nano-titanium dioxide, 8 parts of silane coupling agent and 100 parts of acrylic resin, mixing them evenly, and stirring and reacting at 80°C for 5 hours to obtain the modified acrylic resin.

[0064] Preparation Example 4 This preparation example illustrates the preparation of a modified acrylic resin, specifically including: taking 12 parts of rutile nano-titanium dioxide I (particle size of 25 nm), 6 parts of γ-methacryloyloxypropyltrimethoxysilane and 100 parts of acrylic resin, mixing them evenly, and stirring and reacting at 70°C for 4 h to obtain the modified acrylic resin.

[0065] Example 1 This embodiment illustrates a reflective heat-insulating coating and its preparation method. The reflective heat-insulating coating, by weight, comprises: 25 parts of the modified acrylic resin provided in Preparation Example 1, 12 parts of reflective heat-insulating filler, 8 parts of iron oxide red 101, 4 parts of a polymeric dispersant, 2.5 parts of an organosilicon defoamer, 1.5 parts of a polyether-modified polysiloxane leveling agent, 1.5 parts of an alkali-swellable thickener, 0.8 parts of a benzotriazole ultraviolet absorber, and 44.7 parts of a solvent. The reflective heat-insulating filler includes hollow glass microspheres I (actual density 0.28~0.32 g / cm³) in a weight ratio of 4:1. 3 The solvents include xylene and water in a volume ratio of 1.5:1, and rutile titanium dioxide II.

[0066] The preparation of the reflective heat insulation coating specifically includes: (1) taking the reflective heat insulation filler, iron oxide red 101, polymeric dispersant and 22.35 parts of solvent according to the above weight parts, mixing them, and stirring at 1000 r / min for 45 min to obtain a pre-dispersion liquid; (2) taking the pre-dispersion liquid and grinding it in a sand mill (target fineness is 30 μm) to obtain a grinding liquid; (3) taking the modified acrylic resin, organosilicon defoamer, polyether modified polysiloxane leveling agent, alkali swelling thickener, benzotriazole ultraviolet absorber and 22.35 parts of solvent according to the above weight parts and adding them to the grinding liquid, stirring at 500 r / min for 75 min to obtain the reflective heat insulation coating.

[0067] Example 2 This embodiment illustrates a reflective heat-insulating coating and its preparation method. The reflective heat-insulating coating, by weight, comprises: 20 parts of the modified acrylic resin provided in Preparation Example 2, 10 parts of reflective heat-insulating filler, 5 parts of iron oxide red 101, 3 parts of a polymeric dispersant, 2 parts of an organosilicon defoamer, 1 part of a polyether-modified polysiloxane leveling agent, 1 part of an alkali-swellable thickener, 0.5 parts of a benzotriazole ultraviolet absorber, and 57.5 parts of a solvent. The reflective heat-insulating filler includes hollow glass microspheres II (actual density 0.18~0.22 g / cm³) in a weight ratio of 3:1. 3 ) and rutile titanium dioxide II; the solvents include toluene and water in a volume ratio of 1:1.

[0068] The preparation of the reflective heat insulation coating specifically includes: (1) taking the reflective heat insulation filler, iron oxide red 101 and polymeric dispersant according to the above weight parts and adding them to 23 parts of solvent, stirring at 800 r / min for 30 min to obtain a pre-dispersion liquid; (2) taking the pre-dispersion liquid and grinding it in a sand mill (target fineness is 40 μm) to obtain a grinding liquid; (3) taking the modified acrylic resin, organosilicon defoamer, polyether modified polysiloxane leveling agent, alkali swelling thickener, benzotriazole ultraviolet absorber and 34.5 parts of solvent according to the above weight parts and adding them to the grinding liquid, stirring at 400 r / min for 60 min to obtain the reflective heat insulation coating.

[0069] Example 3 This embodiment illustrates a reflective heat-insulating coating and its preparation method. The reflective heat-insulating coating, by weight, comprises: 30 parts of the modified acrylic resin provided in Preparation Example 3, 15 parts of reflective heat-insulating filler, 10 parts of iron oxide red 101, 5 parts of a polymeric dispersant, 3 parts of an organosilicon defoamer, 2 parts of a polyether-modified polysiloxane leveling agent, 2 parts of an alkali-swellable thickener, 1 part of a benzotriazole ultraviolet absorber, and 37 parts of a solvent. The reflective heat-insulating filler includes hollow glass microspheres III (actual density 0.38~0.42 g / cm³) in a weight ratio of 5:1. 3 The solvents include xylene, toluene, and water in a volume ratio of 1:1:1.

[0070] The preparation of the reflective heat insulation coating specifically includes: (1) taking the reflective heat insulation filler, iron oxide red 101, polymeric dispersant and 22.2 parts of solvent according to the above weight parts, and stirring at 1200 r / min for 60 min to obtain a pre-dispersion liquid; (2) taking the pre-dispersion liquid and grinding it in a sand mill (target fineness is 20 μm) to obtain a grinding liquid; (3) taking the modified acrylic resin, organosilicon defoamer, polyether modified polysiloxane leveling agent, alkali swelling thickener, benzotriazole ultraviolet absorber and 14.8 parts of solvent according to the above weight parts and adding them to the grinding liquid, and stirring at 600 r / min for 90 min to obtain the reflective heat insulation coating.

[0071] Example 4 This embodiment uses the method provided in Example 1 to prepare a reflective heat-insulating coating. The difference is that the modified acrylic resin provided in Preparation Example 4 is added in equal parts by weight instead of the modified acrylic resin provided in Preparation Example 1. Other conditions are the same, and a reflective heat-insulating coating is obtained.

[0072] Comparative Example 1 The comparative example uses the method provided in Example 1 to prepare a reflective heat-insulating coating, except that an equal part by weight of acrylic resin is added instead of the modified acrylic resin provided in Example 1, while other conditions are the same, to obtain a reflective heat-insulating coating.

[0073] Comparative Example 2 The comparative example uses the method provided in Example 1 to prepare a reflective heat-insulating coating, except that an equal part by weight of the comparative modified acrylic resin is added instead of the modified acrylic resin provided in Preparation Example 1, while other conditions are the same, to obtain a reflective heat-insulating coating.

[0074] The preparation of the comparative modified acrylic resin includes: (1) taking 12 parts of anatase nano titanium dioxide (particle size of 25 nm, the same below) and 6 parts of γ-methacryloxypropyltrimethoxysilane and mixing them evenly, stirring and reacting at 70°C for 12 h to obtain modified nano titanium dioxide; (2) taking 6 parts of butyl acrylate, 3 parts of acrylic acid, 1 part of hydroxypropyl acrylate and 0.3 g of azobisisobutyronitrile and mixing them evenly to obtain a mixture; (3) taking 25 parts of ethanol and 5 parts of diethylene glycol and mixing them evenly, and simultaneously slowly adding the modified nano titanium dioxide and the mixture at 70°C and 300 rpm (addition time is 3 h). After the addition is completed, the temperature is raised to 75°C, and after reacting for 1 h, 0.1 parts of azobisisobutyronitrile are added. After continuing to react for 3 h, the reaction is stopped. After cooling to 40°C, the pH is adjusted to 7.5 to obtain the comparative modified acrylic resin.

[0075] Test case This test example illustrates the relevant performance of the reflective heat-insulating coatings provided in the above embodiments and comparative examples, referring to GB / T 9271-2008. The method provided in "Standard Test Panels for Paints and Varnishes" involves sequentially degreasing, phosphating, passivating, and drying a standard cold-rolled steel sheet (150mm×70mm×1.5mm). An automotive-grade epoxy primer is then sprayed onto the sheet, baked at 120℃ for 20 minutes, and cooled to 25℃ to form a 30μm thick primer layer. Using an air spray gun (model W-71, nozzle diameter 1.5mm), reflective heat-insulating coatings from the examples and comparative examples are applied in two coats to the primer layer at a spray pressure of 0.4MPa and a spray distance of 25cm (the second coat is applied after 10 minutes of leveling at room temperature following the first coat). After both coats, the coating is leveled at room temperature for 15 minutes and then baked in an oven at 140℃ for 30 minutes to form a 70μm thick dry film. The resulting test panels are then subjected to the following tests: (1) The reflective heat insulation performance of the dry film on each test board was tested according to the method provided in HG / T 4341-2012 Heat Reflective Insulation Coating for Metal Surfaces. The results are shown in Table 1.

[0076] Table 1.

[0077] As shown in Table 1, compared with Comparative Examples 1 and 2, the reflective heat insulation coatings provided in Examples 1 to 4 of the present invention have a solar reflectance of not less than 0.82, a hemispherical emissivity of not less than 0.85, a near-infrared reflectance of not less than 0.75, and a temperature difference on the back of the test panel of not more than 15.8℃, thus exhibiting excellent reflective heat insulation performance.

[0078] (2) The adhesion of the dry film on each test board was tested according to the method provided in GBT9286-1998 Paints and Varnishes Cross-cut Test (the cross-cut spacing was 1 mm). The results are shown in Table 2.

[0079] Table 2.

[0080] As shown in Table 2, compared with Comparative Examples 1 and 2, the reflective heat-insulating coatings provided in Examples 1 to 4 of the present invention are tightly bonded to the cold-rolled steel sheet and have strong adhesion.

[0081] (3) The durability of the dry film on each test board was tested (accelerated aging for 1000h) according to the method provided in GB-T 1865-2009 Paints and Varnishes Artificial climate aging and artificial radiation exposure filtered xenon arc radiation. The results are shown in Table 3.

[0082] Table 3.

[0083] As shown in Table 3, compared with Comparative Examples 1 and 2, the reflective heat-insulating coatings provided in Examples 1 to 4 of the present invention, after being subjected to accelerated aging for 1000 hours, maintain an intact coating structure, and have a gloss retention rate of no less than 85.3% and a color difference of no more than 1.5, demonstrating excellent durability.

[0084] (4) The salt spray resistance of the dry film on each test board was tested according to the method provided in GB-T 1771-2007 Determination of the resistance of paints and varnishes to neutral salt spray. The results are shown in Table 4.

[0085] Table 4.

[0086] As shown in Table 4, compared with Comparative Examples 1 and 2, the reflective heat-insulating coatings provided in Examples 1 to 4 of the present invention can form a dense coating on the surface of cold-rolled steel plates, effectively blocking salt spray penetration and exhibiting excellent salt spray resistance.

[0087] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A reflective thermal barrier coating, characterized in that, The reflective thermal insulation coating comprises modified acrylic resin, reflective thermal insulation filler, ultraviolet absorber and optional pigments, dispersants, defoamers, leveling agents and thickening agents in a weight ratio of (10-50):(5-20):(0.1-2):(0-15):(0-10):(0-5):(0-4):(0-4); The modified acrylic resin is prepared by modification reaction of nanometer titanium dioxide, silane coupling agent and acrylic resin; The reflective thermal insulation coating comprises hollow glass microspheres and titanium dioxide in a weight ratio of (3-5):

1.

2. The reflective thermal barrier coating of claim 1, wherein, In the preparation of the modified acrylic resin, the crystal form of the nanometer titanium dioxide is anatase and / or rutile; Optionally, the particle size of the nanometer titanium dioxide is 10-50 nm; Optionally, the silane coupling agent comprises one or more of γ-aminopropyl triethoxysilane, γ-methacryloyloxypropyl trimethoxysilane, N-(β-aminoethyl)-γ-aminopropyl triethoxysilane, γ-(2,3-epoxypropoxy) propyl trimethoxysilane and vinyl trimethoxysilane; Optionally, the acrylic resin has a hydroxyl content of 2-8% and a viscosity of 2000-8000 mPa·s.

3. The reflective thermal barrier coating of claim 1, wherein, In the preparation of the modified acrylic resin, the weight ratio of the nanometer titanium dioxide, the silane coupling agent and the acrylic resin is (10-15):(5-8):

100. Optionally, the temperature of the modification reaction is 60-80°C, and the time is 3-5 h.

4. The reflective thermal barrier coating of claim 1, wherein, In the reflective heat-insulating filler, the hollow glass microspheres have a particle size of 10μm~50μm and an actual density of 0.1g / cm³. 3 ~0.5g / cm 3 ; Optionally, the crystal form of the titanium dioxide is anatase and / or rutile.

5. The reflective thermal barrier coating of claim 1, wherein, The reflective thermal insulation coating comprises modified acrylic resin, reflective thermal insulation filler, ultraviolet absorber, pigments, dispersants, defoamers, leveling agents, thickening agents and solvents in a weight ratio of (20-30):(10-15):(0.5-1):(5-10):(3-5):(2-3):(1-2):(1-2):(30-60); Optionally, the ultraviolet absorber is selected from one or more of salicylate ultraviolet absorbers, benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers and triazine ultraviolet absorbers; Optionally, the pigments are selected from one or more of red iron oxide, titanium white, iron black, chrome yellow and iron blue; Optionally, the dispersants are selected from one or more of inorganic dispersants, small molecule dispersants, high molecular weight dispersants and composite dispersants; Optionally, the defoamers are selected from one or more of silicone defoamers, polyether defoamers and polyether-modified silicone defoamers; Optionally, the leveling agents are selected from one or more of polyether-modified polysiloxane leveling agents, acrylate leveling agents, fluorocarbon compound leveling agents and polyether leveling agents; Optionally, the thickening agents are polyurethane associative thickening agents and / or alkali-swellable thickening agents; Optionally, the solvents comprise organic solvents and water in a volume ratio of (1-2):1, and the organic solvents are toluene and / or xylene.

6. The reflective thermal barrier coating of claim 1, wherein, The content of the modified acrylic resin is 20wt%-30wt%, the content of the reflective thermal insulation filler is 10wt%-15wt%, the content of the ultraviolet absorber is 0.5wt%-1wt%, the content of the pigment is 5wt%-10wt%, the content of the dispersant is 3wt%-5wt%, the content of the defoaming agent is 2wt%-3wt%, the content of the leveling agent is 1wt%-2wt%, the content of the thickening agent is 1wt%-2wt%, and the content of the solvent is 35wt%-57.5wt%, based on the total weight of the reflective thermal insulation coating.

7. The method of producing the reflective thermal barrier coating according to any one of claims 1 to 6, characterized in that, The preparation method comprises: mixing the reflective thermal insulation filler and optionally the pigment and the dispersant with the solvent to obtain a pre-dispersion liquid; grinding the pre-dispersion liquid to obtain a grinding liquid; and mixing the grinding liquid, the modified acrylic resin, the ultraviolet absorber, and optionally the defoaming agent, the leveling agent, the thickening agent and the solvent to obtain the reflective thermal insulation coating.

8. The method of claim 7, wherein the reflective thermal barrier coating is prepared by, The stirring speed of the mixing process I is 800r / min-1200r / min, and the time is 30min-60min. Optionally, the target fineness of the grinding process is not greater than 50μm. Optionally, the stirring speed of the mixing process II is 400r / min-600r / min, and the time is 60min-90min.

9. The reflective thermal insulation coating according to any one of claims 1-6, used in the field of automobiles.

10. Use of the reflective thermal barrier coating according to any one of claims 1 to 6, characterized in that The use method comprises: forming a wet layer on the surface of the object to be covered by the reflective thermal insulation coating, and performing a film forming process to form a dry film. The temperature of the film forming process is 120℃-150℃, and the time is 10min-60min.

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