A composite particle modification process with three-dimensional angle-dependent color effect and heat barrier function

Abstract

The application relates to the technical field of composite materials, and discloses a composite particle modification process with three-dimensional goniochromatic effect and heat barrier function, which comprises the following steps: substrate pretreatment, optical layer deposition, functional layer coating, surface modification, dispersion and curing; a multilayer nanometer film optical interference structure formed by alternately stacking high and low refractive index material layers is constructed on the surface of a flaky substrate material with a large diameter-thickness ratio by using a liquid phase deposition method; when light is irradiated, an interference effect is generated, so that the material is endowed with a three-dimensional goniochromatic optical effect, the visual aesthetic feeling and the added value of the product are improved, and a functional layer composed of heat barrier functional fillers is formed by using a specific coating process. The fillers in the functional layer can reflect and scatter infrared radiation and increase the tortuosity of the heat conduction path, block the diffusion of external heat sources and internal heat, so that the heat barrier performance of the final coating and the composite material is improved.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, specifically to a composite particle modification process that combines stereochromic effect with thermal barrier function. Background Technology

[0002] Composite particles are particles formed by the combination of more fundamental particles. Hadrons are an important type of composite particle, composed of quarks and gluons through the strong interaction. Their most stable components, protons and neutrons, are the building blocks of atomic nuclei. Based on the different combinations of quarks within them, hadrons are mainly divided into mesons, which are composed of quark-antiquarks, and baryons, which are composed of three quarks. In addition, there are also multiquark states, glue spheres, and other types.

[0003] Currently, when preparing composite materials that combine visual decoration and thermal protection functions, the optical pigment flakes and thermal insulation fillers are directly added to the resin matrix through physical blending. During the compounding and molding process, it is difficult to achieve a stable, uniform and orderly distribution of the optical pigment flakes and thermal insulation fillers in the matrix. They are prone to phase separation and local aggregation due to density differences and shear forces. As a result, the final coating and product exhibit uneven angle-dependent color effects and low saturation in different areas, and the thermal barrier performance fluctuates greatly, resulting in insufficient performance stability.

[0004] Therefore, a composite particle modification process that combines stereochromic effect with thermal barrier function is proposed to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a composite particle modification process that combines three-dimensional angle-dependent color variation effect with thermal barrier function. This solves the problems mentioned in the background technology, such as uneven angle-dependent color variation effect, low saturation, large fluctuations in thermal barrier performance, and insufficient performance stability in different regions of the final coating and product.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a composite particle modification process that combines stereochromic effect with thermal barrier function, comprising the following steps: Step 1: Substrate pretreatment, select sheet-like substrate material, and clean, activate and dry it; Step 2: Optical layer deposition. On the surface of the pretreated sheet-like substrate material, a multilayer nanofilm with an optical interference structure is constructed by liquid phase deposition to form an optical effect layer. Step 3: Functional layer coating. The substrate material with the deposited optical effect layer is dispersed in the functional slurry, and a thermal barrier functional layer is uniformly coated on its surface by spray drying or fluidized bed coating process. Step 4: Surface modification. The coated composite particles are subjected to surface coupling treatment to obtain surface-modified composite particles. Step 5: Dispersion and curing. The surface-modified composite particles are dispersed in a photocurable or thermocurable resin. After stirring and degassing, they are cured under a specific wavelength of ultraviolet light or heating conditions to obtain the final functional coating or composite material. In step two, the multilayer nanofilm of the optical interference structure is composed of alternating layers of high-refractive-index material and low-refractive-index material, with a total of 5-15 layers and a single layer thickness of 30-150 nanometers. In step three, the functional slurry is made from the following raw materials in parts by weight: 40-60 parts of heat-barrier functional filler, 20-30 parts of bonding resin, 1-5 parts of dispersant, and 10-20 parts of solvent.

[0007] Preferably, in step one, the substrate pretreatment includes the following steps: placing the sheet substrate material in an ultrasonic cleaning tank containing surfactant and deionized water, ultrasonically cleaning at a frequency of 40-80kHz for 10-30 minutes, rinsing with deionized water until neutral after cleaning, then immersing the cleaned substrate material in a 5-15% silane coupling agent ethanol solution, activating it at 50-70℃ for 1-2 hours, and then drying it in an oven at 80-120℃ for 2-4 hours to obtain the activated sheet substrate material.

[0008] Preferably, the sheet-like matrix material is a sheet-like material with an aspect ratio greater than 50, selected from mica sheets, glass flakes, talc sheets, or alumina sheets, with an average particle size D50 of 10-50 micrometers; the surfactant is sodium dodecylbenzenesulfonate or polyethylene glycol octylphenyl ether, with a mass concentration of 0.1-0.5% in the cleaning solution; and the silane coupling agent is at least one selected from γ-aminopropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, or vinyltriethoxysilane.

[0009] Preferably, in step two, the optical layer deposition is performed using a liquid phase deposition method, specifically including the following steps: The activated sheet-like matrix material is dispersed in a precursor solution A containing a metal alkoxide. Precursor solution A consists of tetrabutyl titanate, ethanol, water, and a catalyst in a volume ratio of 1-3:5-10:0.5-1.5:0.01-0.1. The mixture is stirred in a water bath at 40-60°C for 2-6 hours. After the reaction, the mixture is centrifuged, and the solid product is washed 2-3 times with ethanol, dried at 80°C, and then calcined at 400-600°C for 1-3 hours to form a high-refractive-index titanium dioxide layer. The material with the deposited high-refractive-index layer is then... The product is redispersed in precursor solution B, which is composed of tetraethyl orthosilicate, ethanol, water, and ammonia in a volume ratio of 0.5-2:8-15:1-3:0.05-0.2. The mixture is stirred and reacted at room temperature for 4-8 hours. After the reaction, the product is centrifuged and washed with ethanol 2-3 times. The product is then dried at 80°C to form a low-refractive-index silica layer. The deposition process of the high-refractive-index layer and the low-refractive-index layer is repeated alternately until the designed total number of layers is reached, thus obtaining optical effect particles with stereochromatic effect.

[0010] Preferably, the catalyst is hydrochloric acid or nitric acid, the high refractive index material layer is at least one of titanium dioxide, ferric oxide or zinc sulfide, and the low refractive index material layer is at least one of silicon dioxide, magnesium fluoride or aluminum oxide.

[0011] Preferably, in step three, the preparation method of the functional slurry is as follows: the heat-barrier functional filler, dispersant and half of the solvent are added to a high-speed shear emulsifier and pre-dispersed for 10-20 minutes at a speed of 3000-8000 r / min to form slurry A. The bonding resin is dissolved in the remaining half of the solvent and stirred until completely dissolved to form solution B. Solution B is slowly added to slurry A while stirring at a speed of 500-1000 r / min. After the addition is complete, the speed is increased to 1000-2000 r / min and stirring is continued for 30-60 minutes to obtain the functional slurry.

[0012] Preferably, the heat-barrier functional filler is an inorganic filler, selected from at least two of potassium hexatite whiskers, zirconium dioxide aerogel microspheres, hollow glass microspheres, or boron nitride sheets, with an average particle size D50 of 0.5-5 micrometers; the bonding resin is a high-temperature resistant organic resin, selected from silicone resin, silicone-modified acrylic resin, or polyimide resin; the dispersant is a polycarboxylate-type, polyurethane-type, or modified polysiloxane-type polymeric dispersant; and the solvent is an organic solvent compatible with the bonding resin, selected from isopropanol, butanone, propylene glycol methyl ether acetate, or N,N-dimethylformamide.

[0013] Preferably, in step three, the specific parameters of the spray drying or fluidized bed coating process are as follows: When using spray drying technology, the specific parameters are: inlet air temperature 100-180℃, outlet air temperature 50-90℃, atomizer speed 10000-20000r / min, and functional slurry feed rate 5-20mL / min. When using fluidized bed coating process, the specific parameters are: inlet air temperature 100-180℃, outlet air temperature 50-90℃, fluidizing gas velocity 0.5-2.0m³ / min, and functional slurry feed rate 5-20mL / min. The coating process takes 30-90 minutes to form a thermal barrier layer on the surface of the optical effect particles. The thickness of this layer accounts for 10%-30% of the total thickness of the composite particles.

[0014] Preferably, in step four, the surface coupling treatment includes the following steps: adding composite particles coated with a thermal barrier functional layer to a composite treatment solution containing a silane coupling agent and a titanate coupling agent. The composite treatment solution is prepared by mixing silane coupling agent, titanate coupling agent, anhydrous ethanol, and water in a mass ratio of 1-3:0.5-2:50-80:1-5, adjusting the pH to 4-5 with acetic acid, and stirring and refluxing in a water bath at 60-80°C at a speed of 200-500 r / min for 1-2 hours. After treatment, the particles are centrifuged, washed with ethanol, and vacuum dried at 80-100°C for 4-6 hours to obtain surface-modified composite particles.

[0015] Preferably, in step five, the dispersion and curing includes the following steps: mixing the surface-modified composite particles, photocurable resin or thermocurable resin, leveling agent, and defoamer in a weight ratio of 10-30:100:0.1-0.5:0.05-0.2, wherein the leveling agent is at least one of polyacrylate, silicone, or fluorocarbon compound leveling agents, and the defoamer is at least one of mineral oil, polyether-modified silicone, or polysiloxane defoamers; first, a planetary mixer is used at a speed of 500-1000 rpm. Stir and degas for 20-40 minutes at 00 r / min and a vacuum of -0.08 to -0.1 MPa to obtain a uniformly dispersed composite slurry. Then, coat the composite slurry onto the substrate. When using a photocurable resin, irradiate it with ultraviolet light at a wavelength of 365 nm and a light intensity of 50-100 mW / cm² for 10-30 seconds to cure. When using a thermocurable resin, place the coated substrate in an oven at 80-150°C and cure for 20-60 minutes to finally form a functional coating or composite material.

[0016] Compared with the prior art, the present invention provides a composite particle modification process that combines stereochromic effect with thermal barrier function, and has the following beneficial effects: 1. In this invention, a multilayer nanofilm optical interference structure composed of alternating layers of high and low refractive index materials is constructed on the surface of a sheet-like substrate material with a large aspect ratio using liquid phase deposition. When light is irradiated, an interference effect is generated, thereby giving the material a three-dimensional angle-dependent color optical effect, enhancing the visual aesthetics and added value of the product.

[0017] 2. In this invention, a functional layer composed of thermally barrier fillers is formed on the surface of particles that already possess optical effects using a specific coating process. The fillers in this functional layer can reflect and scatter infrared radiation and increase the tortuosity of the heat conduction path, blocking the diffusion of external heat sources and internal heat, thereby improving the thermal barrier performance of the final coating and composite material, enabling it to play a protective role in high-temperature and temperature-varying environments.

[0018] 3. In this invention, surface coupling treatment of the final composite particles improves their dispersion stability and interfacial compatibility in the subsequent resin system. Combined with the dispersion and curing processes, this ensures that the optical effect layer and the thermal barrier functional layer maintain structural integrity and uniform distribution in the final cured coating and composite material, and are firmly bonded to the matrix. This allows both the stereochromatic effect and the thermal barrier function to function stably and persistently. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: A composite particle modification process that combines stereochromic effect and thermal barrier function includes the following steps: Step 1: Substrate pretreatment, select sheet-like substrate material, and clean, activate and dry it; Step 2: Optical layer deposition. On the surface of the pretreated sheet-like substrate material, a multilayer nanofilm with an optical interference structure is constructed by liquid phase deposition to form an optical effect layer. Step 3: Functional layer coating. The substrate material with the deposited optical effect layer is dispersed in the functional slurry, and a thermal barrier functional layer is uniformly coated on its surface by spray drying process. Step 4: Surface modification. The coated composite particles are subjected to surface coupling treatment to obtain surface-modified composite particles. Step 5: Dispersion and curing. The surface-modified composite particles are dispersed in a photocurable resin. After stirring and degassing, the mixture is cured under a specific wavelength of ultraviolet light to obtain the final functional coating. In step two, the multilayer nanofilm of the optical interference structure is composed of alternating layers of high-refractive-index material and low-refractive-index material, with a total of 5 layers and a single layer thickness of 30 nanometers. In step three, the functional slurry is made from the following raw materials in parts by weight: 40 parts of heat-barrier functional filler, 20 parts of binder resin, 1 part of dispersant, and 10 parts of solvent.

[0021] In step one, the substrate pretreatment includes the following steps: the sheet substrate material is placed in an ultrasonic cleaning tank containing surfactant and deionized water, and ultrasonically cleaned at a frequency of 40kHz for 10 minutes. After cleaning, it is rinsed with deionized water until neutral. Then, the cleaned substrate material is immersed in a 5% silane coupling agent ethanol solution and activated at 50°C for 1 hour. After removal, it is dried in an oven at 80°C for 2 hours to obtain the activated sheet substrate material.

[0022] The sheet-like matrix material is a sheet-like material with an aspect ratio greater than 50, specifically selected from mica sheets, with an average particle size D50 of 10 micrometers. The surfactant is sodium dodecylbenzenesulfonate, with a mass concentration of 0.1% in the cleaning solution. The silane coupling agent is γ-aminopropyltriethoxysilane.

[0023] In step two, the optical layer deposition employs a liquid phase deposition method, specifically including the following steps: The activated sheet-like matrix material was dispersed in a precursor solution A containing a metal alkoxide. Precursor solution A consisted of tetrabutyl titanate, ethanol, water, and catalyst in a volume ratio of 1:5:0.5:0.01. The mixture was stirred in a water bath at 40°C for 2 hours. After the reaction, the mixture was centrifuged, and the solid product was washed twice with ethanol and dried at 80°C. Subsequently, it was calcined at 400°C for 1 hour to form a high-refractive-index titanium dioxide layer. The material with the high-refractive-index layer deposited was redispersed in a precursor solution B, which consisted of tetraethyl orthosilicate, ethanol, water, and ammonia in a volume ratio of 0.5:8:1:0.05. The mixture was stirred at room temperature for 4 hours. After the reaction, the mixture was centrifuged, and the solid product was washed twice with ethanol and dried at 80°C to form a low-refractive-index silica layer. By repeating the aforementioned deposition process of high-refractive-index and low-refractive-index layers alternately until the designed total number of layers was reached, optical effect particles with stereochromatic angle-dependent color effects were obtained.

[0024] The catalyst is hydrochloric acid, the high refractive index material layer is titanium dioxide, and the low refractive index material layer is silicon dioxide.

[0025] In step three, the preparation method of the functional slurry is as follows: the heat-barrier functional filler, dispersant and half of the solvent are added to a high-speed shear emulsifier and pre-dispersed for 10 minutes at a speed of 3000 r / min to form slurry A. The bonding resin is dissolved in the remaining half of the solvent and stirred until completely dissolved to form solution B. Solution B is slowly added to slurry A while stirring at a speed of 500 r / min. After the addition is complete, the speed is increased to 1000 r / min and stirring is continued for 30 minutes to obtain the functional slurry.

[0026] The heat-barrier functional filler is an inorganic filler composed of potassium hexatitanate whiskers and zirconium dioxide aerogel microspheres, with an average particle size D50 of 0.5 micrometers. The binder resin is a high-temperature resistant organic resin, the dispersant is a polycarboxylate type, and the solvent is an organic solvent compatible with the binder resin, specifically selected from isopropanol.

[0027] In step three, the specific parameters for the spray drying process are as follows: The inlet air temperature is 100℃, the outlet air temperature is 50℃, the atomizer speed is 10000r / min, and the feed rate of the functional slurry is 5mL / min. The coating process takes 30 minutes to form a thermal barrier layer on the surface of the optical effect particles. The thickness of this layer accounts for 10% of the total thickness of the composite particles.

[0028] In step four, the surface coupling treatment includes the following steps: the composite particles coated with the thermal barrier functional layer are added to a composite treatment solution containing silane coupling agent and titanate coupling agent. The composite treatment solution is prepared by mixing silane coupling agent, titanate coupling agent, anhydrous ethanol and water in a mass ratio of 1:0.5:50:1, and the pH is adjusted to 4 with acetic acid. The mixture is stirred and refluxed in a 60°C water bath at a speed of 200 r / min for 1 hour. After the treatment is completed, the particles are centrifuged, washed with ethanol, and vacuum dried at 80°C for 4 hours to obtain surface-modified composite particles.

[0029] Step 5, dispersion and curing, includes the following steps: the surface-modified composite particles, UV-curable resin, leveling agent, and defoamer are mixed in a weight ratio of 10:100:0.1:0.05. The leveling agent is a polyacrylate leveling agent, and the defoamer is a mineral oil defoamer. First, a planetary mixer is used to stir and degas for 20 minutes under the conditions of 500 r / min and a vacuum degree of -0.08 MPa to obtain a uniformly dispersed composite slurry. Then, the composite slurry is coated on the substrate and cured by irradiation under ultraviolet light with a wavelength of 365 nm and a light intensity of 50 mW / cm² for 10 seconds to finally form a functional coating.

[0030] Example 2: A composite particle modification process that combines stereochromic effect and thermal barrier function includes the following steps: Step 1: Substrate pretreatment, select sheet-like substrate material, and clean, activate and dry it; Step 2: Optical layer deposition. On the surface of the pretreated sheet-like substrate material, a multilayer nanofilm with an optical interference structure is constructed by liquid phase deposition to form an optical effect layer. Step 3: Functional layer coating. The substrate material with the deposited optical effect layer is dispersed in the functional slurry, and a thermal barrier functional layer is uniformly coated on its surface by spray drying process. Step 4: Surface modification. The coated composite particles are subjected to surface coupling treatment to obtain surface-modified composite particles. Step 5: Dispersion and curing. The surface-modified composite particles are dispersed in a photocurable resin. After stirring and degassing, the mixture is cured under a specific wavelength of ultraviolet light to obtain the final functional coating. In step two, the multilayer nanofilm of the optical interference structure is composed of alternating layers of high-refractive-index material and low-refractive-index material, with a total of 10 layers and a single layer thickness of 90 nanometers. In step three, the functional slurry is made from the following raw materials in parts by weight: 50 parts of heat-barrier functional filler, 25 parts of binder resin, 3 parts of dispersant, and 15 parts of solvent.

[0031] In step one, the substrate pretreatment includes the following steps: the sheet substrate material is placed in an ultrasonic cleaning tank containing surfactant and deionized water, and ultrasonically cleaned at a frequency of 60kHz for 20 minutes. After cleaning, it is rinsed with deionized water until neutral. Then, the cleaned substrate material is immersed in a 10% silane coupling agent ethanol solution and activated at 60℃ for 1.5 hours. After removal, it is dried in an oven at 100℃ for 3 hours to obtain the activated sheet substrate material.

[0032] The sheet-like matrix material is a sheet-like material with an aspect ratio greater than 50, specifically selected from mica sheets, with an average particle size D50 of 30 micrometers. The surfactant is sodium dodecylbenzenesulfonate, with a mass concentration of 0.3% in the cleaning solution. The silane coupling agent is γ-aminopropyltriethoxysilane.

[0033] In step two, the optical layer deposition employs a liquid phase deposition method, specifically including the following steps: The activated sheet-like matrix material was dispersed in a precursor solution A containing a metal alkoxide. Precursor solution A consisted of tetrabutyl titanate, ethanol, water, and catalyst in a volume ratio of 2:7:1:0.05. The mixture was stirred in a 50°C water bath for 4 hours. After the reaction, the mixture was centrifuged, and the solid product was washed twice with ethanol and dried at 80°C. Subsequently, it was calcined at 500°C for 2 hours to form a high-refractive-index titanium dioxide layer. The material with the high-refractive-index layer was redispersed in a precursor solution B, which consisted of tetraethyl orthosilicate, ethanol, water, and ammonia in a volume ratio of 1:12:2:0.1. The mixture was stirred at room temperature for 6 hours. After the reaction, the mixture was centrifuged, and the solid product was washed twice with ethanol and dried at 80°C to form a low-refractive-index silica layer. By repeating the deposition process of the high-refractive-index layer and the low-refractive-index layer alternately until the designed total number of layers was reached, optical effect particles with stereochromatic angle-dependent color effects were obtained.

[0034] The catalyst is hydrochloric acid, the high refractive index material layer is titanium dioxide, and the low refractive index material layer is silicon dioxide.

[0035] In step three, the preparation method of the functional slurry is as follows: the heat-barrier functional filler, dispersant and half of the solvent are added to a high-speed shear emulsifier and pre-dispersed for 15 minutes at a speed of 5000 r / min to form slurry A. The bonding resin is dissolved in the remaining half of the solvent and stirred until completely dissolved to form solution B. Solution B is slowly added to slurry A while stirring at a speed of 700 r / min. After the addition is complete, the speed is increased to 1500 r / min and stirring is continued for 45 minutes to obtain the functional slurry.

[0036] The heat-barrier functional filler is an inorganic filler composed of hollow glass microspheres and boron nitride sheets, with an average particle size D50 of 3 micrometers. The binding resin is a high-temperature resistant organic resin, the dispersant is a polycarboxylate type, and the solvent is an organic solvent compatible with the binding resin, specifically selected from isopropanol.

[0037] In step three, the specific parameters for the spray drying process are as follows: The inlet air temperature is 150℃, the outlet air temperature is 70℃, the atomizer speed is 15000r / min, and the feed rate of the functional slurry is 15mL / min. The coating process takes 60 minutes to form a thermal barrier layer on the surface of the optical effect particles. The thickness of this layer accounts for 20% of the total thickness of the composite particles.

[0038] In step four, the surface coupling treatment includes the following steps: the composite particles coated with the thermal barrier functional layer are added to a composite treatment solution containing silane coupling agent and titanate coupling agent. The composite treatment solution is prepared by mixing silane coupling agent, titanate coupling agent, anhydrous ethanol and water in a mass ratio of 2:1:65:3, and the pH is adjusted to 4.5 with acetic acid. The mixture is then stirred and refluxed in a 70°C water bath at 350 r / min for 1.5 hours. After the treatment is completed, the particles are centrifuged, washed with ethanol, and vacuum dried at 90°C for 5 hours to obtain the surface-modified composite particles.

[0039] Step 5, dispersion and curing, includes the following steps: the surface-modified composite particles, UV-curable resin, leveling agent, and defoamer are mixed in a weight ratio of 20:100:0.3:0.1. The leveling agent is a polyacrylate leveling agent, and the defoamer is a mineral oil defoamer. First, a planetary mixer is used to stir and degas for 30 minutes under the conditions of 700 r / min and a vacuum degree of -0.09 MPa to obtain a uniformly dispersed composite slurry. Then, the composite slurry is coated on the substrate and cured by irradiation under ultraviolet light with a wavelength of 365 nm and a light intensity of 70 mW / cm² for 20 seconds to finally form a functional coating.

[0040] Example 3: A composite particle modification process that combines stereochromic effect and thermal barrier function includes the following steps: Step 1: Substrate pretreatment, select sheet-like substrate material, and clean, activate and dry it; Step 2: Optical layer deposition. On the surface of the pretreated sheet-like substrate material, a multilayer nanofilm with an optical interference structure is constructed by liquid phase deposition to form an optical effect layer. Step 3: Functional layer coating. The substrate material with the deposited optical effect layer is dispersed in the functional slurry, and a thermal barrier functional layer is uniformly coated on its surface through a fluidized bed coating process. Step 4: Surface modification. The coated composite particles are subjected to surface coupling treatment to obtain surface-modified composite particles. Step 5: Dispersion and curing. The surface-modified composite particles are dispersed in a thermosetting resin. After stirring and degassing, the resin is cured and molded under specific heating conditions to obtain the final composite material. In step two, the multilayer nanofilm of the optical interference structure is composed of alternating layers of high-refractive-index material and low-refractive-index material, with a total of 15 layers and a single layer thickness of 150 nanometers. In step three, the functional slurry is made from the following raw materials in parts by weight: 60 parts of heat-barrier functional filler, 30 parts of binder resin, 5 parts of dispersant, and 20 parts of solvent.

[0041] In step one, the substrate pretreatment includes the following steps: the sheet substrate material is placed in an ultrasonic cleaning tank containing surfactant and deionized water, and ultrasonically cleaned at a frequency of 80kHz for 30 minutes. After cleaning, it is rinsed with deionized water until neutral. Then, the cleaned substrate material is immersed in a 15% silane coupling agent ethanol solution and activated at 70℃ for 2 hours. After removal, it is dried in an oven at 120℃ for 4 hours to obtain the activated sheet substrate material.

[0042] The sheet-like matrix material is a sheet-like material with an aspect ratio greater than 50, specifically selected from mica sheets with an average particle size D50 of 50 micrometers. The surfactant is sodium dodecylbenzenesulfonate, with a mass concentration of 0.5% in the cleaning solution. The silane coupling agent is γ-aminopropyltriethoxysilane.

[0043] In step two, the optical layer deposition employs a liquid phase deposition method, specifically including the following steps: The activated sheet-like matrix material was dispersed in a precursor solution A containing a metal alkoxide. Precursor solution A consisted of tetrabutyl titanate, ethanol, water, and catalyst in a volume ratio of 3:10:1.5:0.1. The mixture was stirred in a water bath at 60°C for 6 hours. After the reaction, the mixture was centrifuged, and the solid product was washed three times with ethanol and dried at 80°C. Subsequently, it was calcined at 600°C for 3 hours to form a high-refractive-index titanium dioxide layer. The material with the high-refractive-index layer was redispersed in a precursor solution B, which consisted of tetraethyl orthosilicate, ethanol, water, and ammonia in a volume ratio of 2:15:3:0.2. The mixture was stirred at room temperature for 8 hours. After the reaction, the mixture was centrifuged, and the solid product was washed three times with ethanol and dried at 80°C to form a low-refractive-index silica layer. By repeating the deposition process of the high-refractive-index layer and the low-refractive-index layer alternately until the designed total number of layers was reached, optical effect particles with stereochromatic angle-dependent color effects were obtained.

[0044] The catalyst is hydrochloric acid, the high refractive index material layer is titanium dioxide, and the low refractive index material layer is silicon dioxide.

[0045] In step three, the preparation method of the functional slurry is as follows: the heat-barrier functional filler, dispersant and half of the solvent are added to a high-speed shear emulsifier and pre-dispersed for 20 minutes at a speed of 8000 r / min to form slurry A. The bonding resin is dissolved in the remaining half of the solvent and stirred until completely dissolved to form solution B. Solution B is slowly added to slurry A while stirring at a speed of 1000 r / min. After the addition is complete, the speed is increased to 2000 r / min and stirring is continued for 60 minutes to obtain the functional slurry.

[0046] The heat-barrier functional filler is an inorganic filler composed of potassium hexatitanate whiskers and hollow glass microspheres, with an average particle size D50 of 5 micrometers. The binder resin is a high-temperature resistant organic resin, the dispersant is a polycarboxylate type, and the solvent is an organic solvent compatible with the binder resin, specifically selected from isopropanol.

[0047] In step three, the specific parameters of the fluidized bed coating process are as follows: The inlet air temperature is 150℃, the outlet air temperature is 70℃, the fluidizing gas velocity is 1.5m³ / min, and the feed rate of the functional slurry is 15mL / min. The coating process takes 90 minutes to form a thermal barrier layer on the surface of the optical effect particles. The thickness of this layer accounts for 30% of the total thickness of the composite particles.

[0048] In step four, the surface coupling treatment includes the following steps: the composite particles coated with the thermal barrier functional layer are added to a composite treatment solution containing silane coupling agent and titanate coupling agent. The composite treatment solution is prepared by mixing silane coupling agent, titanate coupling agent, anhydrous ethanol and water in a mass ratio of 3:2:80:5, and the pH is adjusted to 5 with acetic acid. The mixture is then stirred and refluxed in an 80°C water bath at a speed of 500 r / min for 2 hours. After the treatment is completed, the particles are centrifuged, washed with ethanol, and vacuum dried at 100°C for 6 hours to obtain the surface-modified composite particles.

[0049] Step 5, dispersion and curing, includes the following steps: the surface-modified composite particles, thermosetting resin, leveling agent, and defoamer are mixed in a weight ratio of 30:100:0.5:0.2. The leveling agent is a polyacrylate leveling agent, and the defoamer is a mineral oil defoamer. First, a planetary mixer is used to stir and defoam for 40 minutes at a speed of 1000 r / min and a vacuum degree of -0.1 MPa to obtain a uniformly dispersed composite slurry. Then, the composite slurry is coated onto the substrate, and the coated substrate is placed in a drying oven at 150°C for 60 minutes to cure, finally forming a composite material.

[0050] Comparative Example 1: The difference between this comparative example and Example 1 is that, in this comparative example, a multilayer nanofilm with an optical interference structure was not constructed on the surface of the sheet-like substrate material during the optical layer deposition.

[0051] Comparative Example 2: The difference between this comparative example and Example 1 is that, in this comparative example, a thermal barrier functional layer was not coated on the surface of the optical effect particles during the functional layer coating.

[0052] Comparative Example 3: The difference between this comparative example and Example 1 is that the coated composite particles were not subjected to surface coupling treatment.

[0053] Comparative Example 4: The difference between this comparative example and Example 1 is that in this comparative example, the composite particles are dispersed in a resin that does not contain leveling agents and defoamers during dispersion and curing.

[0054] The composite particles and their modified coatings prepared in Examples 1-3 and Comparative Examples 1-4, which possess both stereochromic effect and thermal barrier function, were subjected to performance tests. The test items and methods are as follows: The angle-dependent color difference effect test was conducted under the environmental conditions of standard light source D65 and observation angles of 15°, 45° and 110°. A multi-angle spectrophotometer was used to measure the chromaticity coordinates L, a, b* of the coating surface at different angles, and the total color difference ΔE was calculated to quantify the intensity of color change with the observation angle.

[0055] Thermal barrier performance testing was conducted using a thermal conductivity meter based on the heat flow method. Under steady-state conditions with the hot plate temperature set at 50℃ and the cold plate temperature set at 20℃, resulting in a temperature difference of 30℃, the thermal resistance of a standard substrate sample coated with a composite particle functional coating was measured, and its thermal conductivity was calculated to evaluate the heat insulation effect of the coating.

[0056] The dispersion stability test involved dispersing the surface-modified composite particles in a specified resin at a fixed ratio to prepare a slurry. The slurry was placed in a transparent sample tube and allowed to stand at room temperature for 168 hours. The stratification height and precipitate volume were observed and recorded, and the sedimentation ratio was calculated to evaluate the long-term dispersion stability and anti-agglomeration performance of the composite particles in the resin matrix.

[0057] Coating adhesion and temperature cycling tests were conducted. The cured coating underwent a cross-cut adhesion test, with results ranging from 0 to 5. Subsequently, the test sample was placed in a -20°C environment for 2 hours, followed by a transfer to an 80°C oven for 2 hours; this constituted one temperature cycle. This process was repeated 10 times. Afterward, the adhesion was tested again on the original cross-cut area, and the change in the grade was recorded to evaluate the coating's adhesion durability after temperature variations.

[0058] The test data of the composite particle functional coatings prepared in Examples 1-3 and Comparative Examples 1-4 are recorded in the table below: By comparing and analyzing the data in the table, it can be seen that the composite particles and functional coatings prepared using the processes in Examples 1-3, which combine stereochromic effects and thermal barrier functions, exhibit superior performance in all aspects compared to the samples prepared using the processes in Comparative Examples 1-4. This indicates that by constructing a multilayer nanofilm optical interference structure composed of alternating layers of high and low refractive index materials on the surface of a sheet-like substrate material with a large aspect ratio using liquid phase deposition, an interference effect is generated when light shines on it, thereby endowing the material with stereochromic optical effects and enhancing the visual appeal and added value of the product. On the surface of the particles that already possess optical effects, a functional layer composed of thermal barrier fillers is formed using a specific coating process. The fillers in this functional layer can reflect and scatter infrared radiation and increase the tortuosity of the heat conduction path, blocking the diffusion of external heat sources and internal heat, thereby improving the thermal barrier performance of the final coating and composite material, enabling it to play a protective role in high-temperature and temperature-varying environments. By performing surface coupling treatment on the final composite particles, the dispersion stability and interfacial compatibility of the composite particles in the subsequent resin system are improved. By combining dispersion and curing processes, the optical effect layer and the thermal barrier functional layer are ensured to have a complete structure, uniform distribution, and strong bond with the matrix in the final cured coating and composite material, so that the three-dimensional angle-dependent color effect and thermal barrier function can be performed in a long-lasting and stable manner.

[0059] By comparing and analyzing the relevant data in the table, it can be seen that the composite particles and their functional coatings prepared by the modification process of this invention not only possess excellent angle-dependent color variation and thermal barrier properties, but also have good dispersion stability and coating durability. This indicates that the composite particle modification process provided by this invention, through the synergy of structural design, interface control, and a complete formulation, produces materials with balanced and reliable properties and excellent comprehensive performance.

[0060] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0061] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A composite particle modification process that combines stereochromic effect with thermal barrier function, characterized in that: Includes the following steps: Step 1: Substrate pretreatment. Select sheet-like substrate material, and clean, activate, and dry it. Step 2: Optical layer deposition. On the surface of the pretreated sheet-like substrate material, a multilayer nanofilm with an optical interference structure is constructed by liquid phase deposition to form an optical effect layer. Step 3: Functional layer coating. The substrate material with the deposited optical effect layer is dispersed in the functional slurry, and a thermal barrier functional layer is uniformly coated on its surface by spray drying or fluidized bed coating process. Step 4: Surface modification. The coated composite particles are subjected to surface coupling treatment to obtain surface-modified composite particles. Step 5: Dispersion and curing. The surface-modified composite particles are dispersed in a photocurable or thermocurable resin. After stirring and degassing, they are cured under a specific wavelength of ultraviolet light or heating conditions to obtain the final functional coating or composite material. In step two, the multilayer nanofilm of the optical interference structure is composed of alternating layers of high-refractive-index material and low-refractive-index material, with a total of 5-15 layers and a single layer thickness of 30-150 nanometers. In step three, the functional slurry is made from the following raw materials in parts by weight: 40-60 parts of heat-barrier functional filler, 20-30 parts of bonding resin, 1-5 parts of dispersant, and 10-20 parts of solvent.

2. The composite particle modification process according to claim 1, which combines stereochromic effect and thermal barrier function, is characterized in that: In step one, the substrate pretreatment includes the following steps: placing the sheet substrate material in an ultrasonic cleaning tank containing surfactant and deionized water, ultrasonically cleaning at a frequency of 40-80kHz for 10-30 minutes, rinsing with deionized water until neutral after cleaning, then immersing the cleaned substrate material in a 5-15% silane coupling agent ethanol solution, activating it at 50-70℃ for 1-2 hours, and then drying it in an oven at 80-120℃ for 2-4 hours to obtain the activated sheet substrate material.

3. The composite particle modification process according to claim 2, which combines stereochromic effect and thermal barrier function, is characterized in that: The sheet-like matrix material is a sheet-like material with an aspect ratio greater than 50, selected from mica sheets, glass flakes, talc sheets, or alumina sheets, with an average particle size D50 of 10-50 micrometers. The surfactant is sodium dodecylbenzenesulfonate or polyethylene glycol octylphenyl ether, with a mass concentration of 0.1-0.5% in the cleaning solution. The silane coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, or vinyltriethoxysilane.

4. The composite particle modification process according to claim 1, which combines stereochromic effect and thermal barrier function, is characterized in that: In step two, the optical layer deposition is performed using a liquid phase deposition method, specifically including the following steps: The activated sheet-like matrix material is dispersed in a precursor solution A containing a metal alkoxide. Precursor solution A consists of tetrabutyl titanate, ethanol, water, and a catalyst in a volume ratio of 1-3:5-10:0.5-1.5:0.01-0.

1. The mixture is stirred in a water bath at 40-60°C for 2-6 hours. After the reaction, the mixture is centrifuged, and the solid product is washed 2-3 times with ethanol, dried at 80°C, and then calcined at 400-600°C for 1-3 hours to form a high-refractive-index titanium dioxide layer. The material with the deposited high-refractive-index layer is then... The product is redispersed in precursor solution B, which is composed of tetraethyl orthosilicate, ethanol, water, and ammonia in a volume ratio of 0.5-2:8-15:1-3:0.05-0.

2. The mixture is stirred and reacted at room temperature for 4-8 hours. After the reaction, the product is centrifuged and washed with ethanol 2-3 times. The product is then dried at 80°C to form a low-refractive-index silica layer. The deposition process of the high-refractive-index layer and the low-refractive-index layer is repeated alternately until the designed total number of layers is reached, thus obtaining optical effect particles with stereochromatic effect.

5. The composite particle modification process according to claim 4, which combines stereochromic effect and thermal barrier function, is characterized in that: The catalyst is hydrochloric acid or nitric acid, the high refractive index material layer is at least one of titanium dioxide, ferric oxide or zinc sulfide, and the low refractive index material layer is at least one of silicon dioxide, magnesium fluoride or aluminum oxide.

6. The composite particle modification process according to claim 1, which combines stereochromic effect and thermal barrier function, is characterized in that: In step three, the preparation method of the functional slurry is as follows: the heat-barrier functional filler, dispersant and half of the solvent are added to a high-speed shear emulsifier and pre-dispersed for 10-20 minutes at a speed of 3000-8000 r / min to form slurry A. The bonding resin is dissolved in the remaining half of the solvent and stirred until completely dissolved to form solution B. Solution B is slowly added to slurry A while stirring at a speed of 500-1000 r / min. After the addition is complete, the speed is increased to 1000-2000 r / min and stirring is continued for 30-60 minutes to obtain the functional slurry.

7. The composite particle modification process according to claim 6, which combines stereochromic effect and thermal barrier function, is characterized in that: The heat-barrier functional filler is an inorganic filler, selected from at least two of potassium hexatate whiskers, zirconium dioxide aerogel microspheres, hollow glass microspheres, or boron nitride sheets, with an average particle size D50 of 0.5-5 micrometers. The bonding resin is a high-temperature resistant organic resin, selected from silicone resin, silicone-modified acrylic resin, or polyimide resin. The dispersant is a polycarboxylate-type, polyurethane-type, or modified polysiloxane-type polymeric dispersant. The solvent is an organic solvent compatible with the bonding resin, selected from isopropanol, butanone, propylene glycol methyl ether acetate, or N,N-dimethylformamide.

8. The composite particle modification process according to claim 1, which combines stereochromic effect and thermal barrier function, is characterized in that: In step three, the specific parameters of the spray drying or fluidized bed coating process are as follows: When using spray drying technology, the specific parameters are: inlet air temperature 100-180℃, outlet air temperature 50-90℃, atomizer speed 10000-20000r / min, and functional slurry feed rate 5-20mL / min. When using fluidized bed coating process, the specific parameters are: inlet air temperature 100-180℃, outlet air temperature 50-90℃, fluidizing gas velocity 0.5-2.0m³ / min, and functional slurry feed rate 5-20mL / min. The coating process takes 30-90 minutes to form a thermal barrier layer on the surface of the optical effect particles. The thickness of this layer accounts for 10%-30% of the total thickness of the composite particles.

9. The composite particle modification process according to claim 1, which combines stereochromic effect and thermal barrier function, is characterized in that: In step four, the surface coupling treatment includes the following steps: adding composite particles coated with a thermal barrier functional layer to a composite treatment solution containing a silane coupling agent and a titanate coupling agent. The composite treatment solution is prepared by mixing a silane coupling agent, a titanate coupling agent, anhydrous ethanol, and water in a mass ratio of 1-3:0.5-2:50-80:1-5, and adjusting the pH to 4-5 with acetic acid. The mixture is then stirred and refluxed in a water bath at 60-80℃ at a speed of 200-500 r / min for 1-2 hours. After treatment, the mixture is centrifuged, washed with ethanol, and vacuum dried at 80-100℃ for 4-6 hours to obtain surface-modified composite particles.

10. The composite particle modification process according to claim 1, which combines stereochromic effect and thermal barrier function, is characterized in that: In step five, the dispersion and curing process includes the following steps: mixing the surface-modified composite particles, photocurable or thermocurable resin, leveling agent, and defoamer in a weight ratio of 10-30:100:0.1-0.5:0.05-0.

2. The leveling agent is at least one of polyacrylate, silicone, or fluorocarbon compound leveling agents, and the defoamer is at least one of mineral oil, polyether-modified silicone, or polysiloxane defoamers. The mixture is first stirred using a planetary mixer at a speed of 500-1000 rpm. Stirring and degassing at r / min and vacuum of -0.08 to -0.1 MPa for 20-40 minutes yields a uniformly dispersed composite slurry. The composite slurry is then coated onto a substrate. When using a photocurable resin, it is cured by irradiation under ultraviolet light at a wavelength of 365 nm and a light intensity of 50-100 mW / cm² for 10-30 seconds. When using a thermocurable resin, the coated substrate is placed in an oven at 80-150°C and cured for 20-60 minutes, ultimately forming a functional coating or composite material.

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