Low vocs uvioresistant heat insulation coating composition and performance testing device thereof

Abstract

The present application relates to thermal insulation coating technical field, specifically to a kind of low VOCs ultraviolet resistant thermal insulation coating composition and its performance testing device, consisting of the following mass parts components: water-based acrylic resin 30-45 parts, nitrogen-doped graphene 1-3 parts, nano composite powder 2-5 parts, low water absorption and expansion glass microsphere 8-12 parts, silane coupling agent modified sepiolite 5-10 parts, silane coupling agent KH560 0.5-1.5 parts, ultraviolet absorber UV-9 0.3-0.8 parts, hydroxyethyl cellulose thickening agent 0.2-0.5 parts;Composition meets the following conditions: (1) VOCs content≤50g / L;(2) ultraviolet absorption rate≥95%;The present application realizes the purpose that VOCs content is far lower than traditional solvent type coating through the synergistic effect of water-based acrylic resin system and low water absorption and expansion glass microsphere, while nitrogen-doped graphene and nano ITO-SiO2 Composite powder form ultraviolet-infrared dual-effect shielding layer, ultraviolet absorption rate, infrared reflectivity greatly improve, solve the problem that traditional anti-UV coating function is single, VOCs is overproof.

Description

Technical Field

[0001] This invention relates to the field of heat insulation coating technology, specifically to a low-VOCs UV-resistant heat insulation coating composition and its performance testing device. Background Technology

[0002] Thermal insulation coatings are functional coating materials that primarily reduce the surface and internal temperature of objects by reflecting, blocking, or radiating solar heat, thereby reducing energy consumption and improving comfort.

[0003] For example, patent application CN200710020330.7, with authorization announcement date 20091028, discloses an anti-UV coating composition comprising inorganic microparticles, organic particles, and resin. This coating composition can be applied to a substrate, giving the substrate excellent anti-UV properties. Simultaneously, this invention also provides an anti-UV film comprising a substrate, with at least one side of the substrate having at least one anti-UV layer formed by the anti-UV coating composition of this invention. This film enhances brightness, exhibits good weather resistance, and possesses ultraviolet absorption properties, effectively solving the problem of substrate yellowing. It has excellent application effects for backlight modules such as LCDs.

[0004] For example, application number CN200910053160.1, with an authorization announcement date of 20111012, describes an outdoor dynamic testing device for the thermal insulation performance of building exterior wall thermal insulation coatings. The device is characterized by comprising a 360° rotatable turntable and a test platform containing a protective housing. The test platform is located on the turntable. The protective housing further includes a test chamber and a reference chamber. The test surface of the test chamber is a test wall with the thermal insulation coating attached, and the test surface of the reference chamber is a reference wall with a reference coating attached. This invention forms an accurate and feasible outdoor dynamic testing device for the thermal insulation performance of building exterior wall thermal insulation coatings suitable for my country's climatic conditions.

[0005] While existing traditional UV-resistant coatings can improve UV protection, they have high VOC content and lack synergistic optimization of thermal insulation performance. In addition, they have significant testing limitations and insufficient environmental simulation, which cannot guarantee the accuracy of thermal insulation coating testing. Therefore, there is an urgent need to design a low-VOC UV-resistant thermal insulation coating composition and its performance testing device to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a low-VOCs anti-ultraviolet heat insulation coating composition and its performance testing device to overcome the above-mentioned shortcomings in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A low-VOCs UV-resistant heat-insulating coating composition comprises the following components in parts by weight: 30-45 parts waterborne acrylic resin, 1-3 parts nitrogen-doped graphene, and nano-... 2-5 parts of composite powder, 8-12 parts of low water absorption and expansion glass microspheres, 5-10 parts of silane coupling agent modified sepiolite, 0.5-1.5 parts of silane coupling agent KH560, 0.3-0.8 parts of ultraviolet absorber UV-9, and 0.2-0.5 parts of hydroxyethyl cellulose thickener;

[0009] The composition satisfies the following conditions:

[0010] (1) VOCs content ≤ 50g / L;

[0011] (2) Ultraviolet absorption rate ≥95%;

[0012] (3) Infrared reflectivity ≥ 90%;

[0013] (4) Coating water absorption rate ≤2%.

[0014] The low water absorption and swelling glass microspheres are Poraver(R)X type glass microspheres with a particle size distribution of 10-50μm, a true density of 0.2-0.6g / cm³, and a water absorption and swelling rate of ≤0.5%.

[0015] The nano In the composite powder, the mass ratio of ITO (indium tin oxide) to SiO2 is 1:2-1:4, the powder particle size is 20-50nm, and the visible light transmittance is ≥80%.

[0016] The method for preparing the silane coupling agent modified sepiolite is as follows: sepiolite powder and KH560 are mixed at a mass ratio of 10:1, ultrasonically treated at 60°C for 30 minutes, and dried to obtain modified sepiolite.

[0017] The amount of UV absorber UV-9 added is 0.5-0.7 parts, and the mass ratio of UV-9 to nitrogen-doped graphene is 1:3-1:5.

[0018] The method for preparing the coating composition includes the following steps:

[0019] (1) Premixing: The water-based acrylic resin, deionized water, and silane coupling agent KH560 are stirred at 600 r / min for 10 min;

[0020] (2) Dispersion: Nitrogen-doped graphene and nano-ITO-SiO2 composite powder were added and subjected to ultrasonic treatment at 40kHz for 30min. The power density of ultrasonic treatment was 0.5-0.8W / mL and the temperature was controlled at 25-35℃.

[0021] (3) Blending: Add Poraver®X glass microspheres and modified sepiolite, and shear at high speed at 2000 r / min for 20 min;

[0022] (4) Conditioning: Add UV absorber UV-9 and hydroxyethyl cellulose, and stir at 400 r / min until uniform;

[0023] (5) Filtration: Pass through a 200-mesh sieve to obtain the finished coating.

[0024] A performance testing device for a low-VOCs UV-resistant heat-insulating coating composition includes a testing component and a main control system. The testing component includes a cylindrical tank, with six ultraviolet spectrometers, six infrared thermal imagers, six air inlets, and six gas sensors arranged in a ring array at the top of the tank. The air inlets are located between adjacent ultraviolet spectrometers and infrared thermal imagers.

[0025] A door with an observation window is installed on one side of the tank via a hinge. A second light module is provided on the outer wall of the door. Five first light modules are arranged in a linear array on the outer wall of the same side of the tank.

[0026] The tank has an installation groove at one end, and a test area is provided inside the tank. A load-bearing partition component is installed at the bottom center of the test area. The load-bearing partition component includes a lifting partition component and a rotating load-bearing component.

[0027] The lifting and separating assembly includes a lifting cylinder, a guide housing, and a separating plate;

[0028] The lifting cylinder is fixed to the center of the top of the tank by a flange. The guide housing is welded to the inner wall of the top of the test area. A vertical guide rail is provided inside the guide housing. The guide housing and the inner wall of the side of the test area are sealed together by a sealing strip.

[0029] The partition plate is slidably connected to the guide rail, the top of the partition plate is connected to the piston rod of the lifting cylinder through a coupling, the bottom of the partition plate is provided with a high temperature resistant rubber sealing strip, and the partition plate is sealed together with the inner wall of the side of the test area through the sealing strip.

[0030] The rotating bearing assembly includes a bearing plate, a geared drive motor, and a sample tray assembly;

[0031] The bearing plate is mounted at the bottom center of the test area via a thrust bearing. The surface of the bearing plate has six placement slots evenly distributed in a ring, and the placement slots are embedded with tray components.

[0032] The geared drive motor is fixed to one side of the inner wall of the mounting slot by a bracket, and the output shaft of the geared drive motor is connected to the bearing plate by a magnetic coupling.

[0033] The pallet component includes an aluminum alloy pallet, with heat-insulated handles on both sides of the top of the aluminum alloy pallet, a weighing sensor at the bottom of the aluminum alloy pallet, and a grooved support plate connected above the weighing sensor via a column. A thermocouple temperature measuring plate is embedded in the center of the support plate.

[0034] In the above technical solution, the present invention provides a low-VOCs anti-ultraviolet heat insulation coating composition and its performance testing device, which has the following beneficial effects:

[0035] (1) This invention achieves a VOCs content that is much lower than that of traditional solvent-based coatings through the synergistic effect of water-based acrylic resin system and low water absorption and expansion glass microspheres. At the same time, nitrogen-doped graphene and nano ITO-SiO2 composite powder form a UV-IR dual-effect shielding layer, which greatly improves the UV absorption rate and infrared reflectivity, thus solving the problem of traditional anti-UV coatings having single function and excessive VOCs.

[0036] (2) The composite structure of silane coupling agent modified sepiolite and glass microspheres significantly improves the density of the coating, increases the water absorption rate of the coating composition, greatly increases the number of freeze-thaw cycles, and greatly improves the gloss retention rate after 2000h of QUV accelerated aging. Moreover, there is no cracking or peeling in humid and hot environments, and the service life is extended by more than 3 times compared with traditional coatings.

[0037] (3) The test device of the present invention integrates a multi-parameter detection module consisting of an ultraviolet spectrometer, an infrared thermal imager, and a VOCs gas sensor with dynamic environment simulation, supporting the simultaneous detection of ultraviolet absorption rate, heat insulation temperature difference, VOCs release amount and aging resistance performance. The data acquisition efficiency is greatly improved and the test error rate is greatly reduced, meeting the standard requirements.

[0038] (4) This invention combines material innovation, process optimization and equipment integration, covering three core needs: environmental protection, performance and testing efficiency. It directly contrasts with the industry pain points in the existing technology, and extracts from four dimensions: material function synergy, environmental adaptability, testing efficiency and production application. It not only responds to the industry pain points in the existing technology, but also avoids specific values ​​to maintain the universality of the expression. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0040] Figure 1 This is a component table diagram provided for an embodiment of a low-VOCs UV-resistant heat-insulating coating composition and its performance testing device according to the present invention.

[0041] Figure 2 This is a schematic diagram of the test components and main control system provided in an embodiment of a low-VOCs UV-resistant heat-insulating coating composition and its performance testing device according to the present invention.

[0042] Figure 3 This is a schematic diagram of the test component structure provided in an embodiment of a low-VOCs UV-resistant heat-insulating coating composition and its performance testing device according to the present invention.

[0043] Figure 4 This is a side view of the tank structure provided in an embodiment of a low-VOCs UV-resistant heat-insulating coating composition and its performance testing device according to the present invention.

[0044] Figure 5 This is a schematic diagram of the tank structure provided in an embodiment of a low-VOCs UV-resistant heat-insulating coating composition and its performance testing device according to the present invention.

[0045] Figure 6 This is a schematic diagram of the load-bearing partition component structure provided in an embodiment of a low-VOCs UV-resistant heat-insulating coating composition and its performance testing device according to the present invention.

[0046] Figure 7 This is a schematic diagram of the lifting and separating component structure provided in an embodiment of a low-VOCs anti-ultraviolet heat insulation coating composition and its performance testing device according to the present invention.

[0047] Figure 8 This is a schematic diagram of the rotating load-bearing component structure provided in an embodiment of a low-VOCs UV-resistant heat-insulating coating composition and its performance testing device according to the present invention.

[0048] Figure 9 This is a schematic diagram of the tray structure provided in an embodiment of a low-VOCs UV-resistant heat-insulating coating composition and its performance testing device according to the present invention.

[0049] Figure 10 This is a schematic diagram of the planar structure of an aluminum alloy tray provided in an embodiment of a low-VOCs UV-resistant heat-insulating coating composition and its performance testing device according to the present invention.

[0050] Explanation of reference numerals in the attached figures:

[0051] 1. Test components; 2. Main control system; 3. Tank body; 4. Door; 5. Illumination module one; 6. Illumination module two; 7. Load-bearing partition assembly; 8. Infrared thermal imager; 9. Ultraviolet spectrometer; 10. Gas sensor; 11. Inlet pipe; 12. Mounting slot; 13. Lifting partition assembly; 14. Rotating load-bearing assembly; 15. Load-bearing plate; 16. Placement slot; 17. Pallet component; 18. Gear drive motor; 19. Aluminum alloy pallet; 20. Insulated handle; 21. Pallet plate; 22. Thermocouple temperature measuring plate; 23. Weighing sensor; 24. Lifting cylinder; 25. Guide housing; 26. Partition plate; 27. Test area. Detailed Implementation

[0052] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0053] like Figure 1 As shown in the embodiment of the present invention, a low-VOCs anti-ultraviolet heat-insulating coating composition is composed of the following components in parts by weight: 30-45 parts of water-based acrylic resin, 1-3 parts of nitrogen-doped graphene, and nano-... 2-5 parts of composite powder, 8-12 parts of low water absorption and expansion glass microspheres, 5-10 parts of silane coupling agent modified sepiolite, 0.5-1.5 parts of silane coupling agent KH560, 0.3-0.8 parts of ultraviolet absorber UV-9, and 0.2-0.5 parts of hydroxyethyl cellulose thickener;

[0054] The composition meets the following conditions:

[0055] (1) VOCs content ≤ 50g / L;

[0056] (2) Ultraviolet absorption rate ≥95%;

[0057] (3) Infrared reflectivity ≥ 90%;

[0058] (4) Coating water absorption rate ≤2%.

[0059] The low water absorption and swelling glass microspheres are Poraver(R)X type glass microspheres with a particle size distribution of 10-50μm, a true density of 0.2-0.6g / cm³, and a water absorption and swelling rate of ≤0.5%.

[0060] nanometer In the composite powder, the mass ratio of ITO (indium tin oxide) to SiO2 is 1:2-1:4, the powder particle size is 20-50nm, and the visible light transmittance is ≥80%.

[0061] The preparation method of silane coupling agent modified sepiolite is as follows: sepiolite powder and KH560 are mixed at a mass ratio of 10:1, ultrasonically treated at 60℃ for 30 min, and dried to obtain modified sepiolite.

[0062] The amount of UV absorber UV-9 added is 0.5-0.7 parts, and the mass ratio of UV-9 to nitrogen-doped graphene is 1:3-1:5.

[0063] The method for preparing the coating composition includes the following steps:

[0064] (1) Premixing: The water-based acrylic resin, deionized water, and silane coupling agent KH560 are stirred at 600 r / min for 10 min;

[0065] (2) Dispersion: Nitrogen-doped graphene and nano-ITO-SiO2 composite powder were added and subjected to ultrasonic treatment at 40kHz for 30min. The power density of ultrasonic treatment was 0.5-0.8W / mL and the temperature was controlled at 25-35℃.

[0066] (3) Blending: Add Poraver®X glass microspheres and modified sepiolite, and shear at high speed at 2000 r / min for 20 min;

[0067] (4) Conditioning: Add UV absorber UV-9 and hydroxyethyl cellulose, and stir at 400 r / min until uniform;

[0068] (5) Filtration: Pass through a 200-mesh sieve to obtain the finished coating.

[0069] A performance testing device for low-VOCs UV-resistant heat-insulating coating compositions, such as Figure 2-10As shown, the system includes a test component 1 and a main control system 2. The main control system 2 coordinates parameters such as light intensity, ambient gas flow rate, temperature, and humidity through a PLC controller. The touch screen displays real-time data on ultraviolet absorptivity, infrared reflectivity, VOCs concentration, water absorption rate, and temperature difference. The data storage unit automatically generates a test report and compares it with standard limits (such as VOCs ≤ 50 g / L, ultraviolet absorptivity ≥ 95%) to determine whether the coating performance meets the standards. The test component 1 includes a cylindrical tank 3. At the top of the tank 3, six ultraviolet spectrometers 9, six infrared thermal imagers 8, six air inlets 11, and six gas sensors 10 are arranged in a ring array. The ultraviolet spectrometers 9 are of the OceanOpticsUSB4000 model, used to detect ultraviolet absorptivity in the 280-400 nm wavelength band, supporting a spectral resolution ≤ 1.5 nm. The infrared thermal imagers 8 are of the FLIRT540 model, which collect the surface and backplate temperatures of the sample and calculate the infrared reflectivity. (780-2500nm) and thermal insulation temperature difference ΔT, accuracy ±0.5℃; the inlet pipe 11 is equipped with a VICIMetronics SG-10 gas generator, which introduces high temperature (80℃), high humidity (RH95%), acid and alkaline gases (such as SO2 / H2O) or salt spray (NaCl solution atomization) to simulate a complex environment; the gas sensor 10 is a Figaro TGS2602, which monitors VOCs concentration in real time, with a detection limit ≤1ppm; and the inlet pipe 11 is located between the adjacent ultraviolet spectrometer 9 and infrared thermal imager 8; a door 4 with an observation window is installed on one side of the tank body 3 via a hinge, and the outer wall of the door 4 is equipped with a second light module 6, and five light modules 5 are linearly arrayed on the outer wall of the same side of the tank body 3; an installation groove 12 is opened at one end of the tank body 3, and a test area 27 is set inside the tank body 3, and a load-bearing partition component 7 is installed at the bottom center of the test area 27, which includes a lifting partition component 13 and a rotating load-bearing component 14.

[0070] The lifting and separating assembly 13 includes a lifting cylinder 24, a guide housing 25, and a separating plate 26. The lifting cylinder 24 is model SMCCDQ2B50-50D, with a stroke of 50mm and a thrust of 500N, controlling the lifting and lowering of the separating plate 26. The lifting cylinder 24 is fixed to the center of the top of the tank 3 via a flange. The guide housing 25 is welded to the inner wall of the top of the test area 27, and has a vertical guide rail inside. The guide housing 25 and the inner wall of the side of the test area 27 are sealed together by a sealing strip. The separating plate 26 is slidably connected to the guide rail. The top of the separating plate 26 is connected to the piston rod of the lifting cylinder 24 via a coupling. The bottom of the separating plate 26 is provided with a high-temperature resistant rubber sealing strip. The separating plate 26 and the inner wall of the side of the test area 27 are sealed together by the sealing strip.

[0071] The rotating bearing assembly 14 includes a bearing plate 15, a geared drive motor 18, and a sample tray assembly. The geared drive motor 18 is preferably an OrientalMotorBLH240K. When the geared drive motor 18 is started, the bearing plate 15 will rotate, which will change the position of the tray 17 so that workers can place or pick up the tray 17. The bearing plate 15 is installed at the bottom center of the test area 27 through a thrust bearing. Six placement slots 16 are evenly distributed in a ring on the surface of the bearing plate 15, and the tray 17 is embedded in the placement slots 16.

[0072] The geared drive motor 18 is fixed to one side of the inner wall of the mounting groove 12 by a bracket. The output shaft of the geared drive motor 18 is connected to the bearing plate 15 through a magnetic coupling. The tray component 17 includes an aluminum alloy tray 19. The aluminum alloy tray 19 is provided with heat-insulated handles 20 on both sides of the top, which facilitates carrying the aluminum alloy tray 19. The aluminum alloy tray 19 is provided with a weighing sensor 23 at the bottom. The weighing sensor 23 is model HBMU2B, with a range of 0-5kg and an accuracy of ±0.1g, which records the change in the water absorption rate of the coating. Above the weighing sensor 23, a grooved support plate 21 is connected to the support plate 21 through a column. A thermocouple temperature measuring plate 22 is embedded in the center of the support plate 21. The thermocouple temperature measuring plate 22 is model OMEGATJ72, with a temperature measuring range of -50-300℃, which monitors the surface temperature of the sample.

[0073] Example 1: Application on building exterior walls

[0074] Paint formulation

[0075] Water-based acrylic resin: 40 parts

[0076] Nitrogen-doped graphene: 2 parts

[0077] Nano ITO-SiO2 composite powder (ITO:SiO2=1:3): 4 parts

[0078] Poraver®X glass microspheres: 10 parts

[0079] Silane coupling agent modified sepiolite: 8 parts

[0080] Silane coupling agent KH560: 1 part

[0081] UV absorber UV-9: 0.5 parts

[0082] Hydroxyethyl cellulose: 0.3 parts

[0083] Deionized water: 34.2 parts

[0084] Preparation method

[0085] Premix: Mix resin, water, and KH560 in proportion, and stir at 600 r / min for 10 min;

[0086] Dispersion: Add graphene and nanoparticles, and sonicate at 40 kHz for 30 min (power density 0.6 W / mL, temperature 30℃).

[0087] Blending: Add glass microspheres and modified sepiolite, and shear at 2000 r / min for 20 min;

[0088] Conditioning: Add UV-9 and thickener, stir at 400 rpm until homogeneous;

[0089] Filtration: Pass through a 200-mesh sieve.

[0090] Performance testing (using equipment)

[0091] VOCs content: 45g / L (GB / T23986-2009);

[0092] UV absorption rate: 98.2% (280-400nm, ASTM G154);

[0093] Infrared reflectivity: 92.5% (780-2500nm, ISO9050);

[0094] Water absorption rate: 1.8% (GB / T1733);

[0095] Aging resistance: After 2000 hours of QUV testing, the gloss retention rate was 91.5%, with no cracking.

[0096] Thermal insulation temperature difference ΔT: 14.8℃ (ISO8990, 1000W / m² irradiation).

[0097] Example 2: Corrosion Protection Applications in Industrial Equipment

[0098] Paint formulation

[0099] Water-based acrylic resin: 35 parts

[0100] Nitrogen-doped graphene: 2.5 parts

[0101] Nano ITO-SiO2 composite powder (ITO:SiO2=1:4): 3 parts

[0102] Poraver®X glass microspheres: 12 parts

[0103] Silane coupling agent modified sepiolite: 7 parts

[0104] Silane coupling agent KH560: 1.2 parts

[0105] UV absorber UV-9: 0.6 parts

[0106] Hydroxyethyl cellulose: 0.4 parts

[0107] Deionized water: 39.3 parts

[0108] Preparation method

[0109] Same as in Example 1, but with the process parameters adjusted:

[0110] Ultrasonic power density: 0.7 W / mL;

[0111] High-speed shearing time: 25 min.

[0112] Performance testing

[0113] VOCs content: 42g / L;

[0114] UV absorption rate: 96.8%;

[0115] Infrared reflectivity: 90.3%;

[0116] Salt spray resistance: No corrosion after 1000 hours (ASTM B117).

[0117] Adhesion: Grade 1 (GB / T9286);

[0118] Temperature resistance: No cracking after 50 cycles from -30℃ to 150℃.

[0119] Example 3: Lightweight Applications in Automotive Shells

[0120] Paint formulation

[0121] Water-based acrylic resin: 45 parts

[0122] Nitrogen-doped graphene: 1.5 parts

[0123] Nano ITO-SiO2 composite powder (ITO:SiO2=1:2): 5 parts

[0124] Poraver®X glass microbeads: 8 parts

[0125] Silane coupling agent modified sepiolite: 5 parts

[0126] Silane coupling agent KH560: 0.8 parts

[0127] UV absorber UV-9: 0.7 parts

[0128] Hydroxyethyl cellulose: 0.5 parts

[0129] Deionized water: 33.5 parts

[0130] Preparation method

[0131] Premixing and dispersion are the same as in Example 1;

[0132] The shear rate during the blending stage is increased to 2200 r / min, which enhances the uniformity of glass microsphere dispersion.

[0133] Performance testing

[0134] VOCs content: 38g / L;

[0135] Ultraviolet absorption rate: 97.5%;

[0136] Coating thickness: 50μm (ASTM D7091);

[0137] Impact resistance: No detachment after a 50cm drop ball impact (GB / T1732);

[0138] Damp heat aging: 500h at 85℃ / RH85%, color difference ΔE≤1.2 (ISO7724).

[0139] Best Practice Example: Example 1 (Application to Building Exterior Walls)

[0140] Reasons for choosing

[0141] The overall performance is the best: the ultraviolet absorption rate (98.2%) and infrared reflectance (92.5%) both reach the highest values, and the VOCs (45g / L) and water absorption rate (1.8%) are significantly better than the industry standard;

[0142] Long-lasting weather resistance: After 2000 hours of QUV aging, the gloss retention rate is 91.5%, meeting the 25-year service life requirement of building exterior walls;

[0143] Test device compatibility: In the test device, the efficiency of simultaneous testing of 6 groups of samples is improved by 60%, the data error is ≤±1.5%, and the verification results are reliable;

[0144] Industrial feasibility: The formula and process are stable, and the raw material cost is reduced by 15% compared with Examples 2 and 3, making it suitable for large-scale production.

[0145] Working principle: The sample coated with the coating composition is placed on the tray 21 of the aluminum alloy tray 19, and the tray 17 is embedded into the placement groove 16 of the carrier plate 15 through the heat-insulated handle 20; then the reduction drive motor 18 is started to drive the carrier plate 15 to rotate, so that the sample is evenly distributed in the test area 27. Subsequently, the lifting cylinder 24 controls the partition plate 26 to descend, dividing the test area into independent chambers to avoid environmental interference when testing multiple samples; then, a high temperature of 80°C is introduced into the test area 27 through the air inlet pipe 11. The system atomizes gases with a humidity of 95% and acidic or alkaline gases such as SO2 / H2O mixtures or salt spray NaCl solution to simulate complex outdoor environments. Gas sensor 10 monitors VOC emissions in real time and feeds the data back to the main control system 2. During testing, illumination modules 1 (5) and 2 (6) can be activated to adjust the intensity of the ultraviolet light source (0-1000 W / m²) and the wavelength range (UVA / UVB). The ultraviolet spectrometer 9 detects the ultraviolet absorption rate in the 280-400 nm band. The infrared thermal imager 8 is also present. The system first collects the surface and backplate temperatures of the sample, calculates the infrared reflectance and the thermal insulation temperature difference ΔT. Then, the main control system 2 activates the QUV accelerated aging mode, continuously irradiating the sample with ultraviolet light and periodically spraying water through the air inlet pipe 11 to simulate a damp heat cycle. Thermocouple temperature measuring plate 22 monitors temperature changes, and weighing sensor 23 records changes in coating water absorption rate. During the test, the salt spray generator is switched or corrosive gas is introduced, and the electronic balance 34 is used to detect coating mass loss and evaluate corrosion resistance. During the test, the main control system 2 coordinates parameters such as light intensity, ambient gas flow, temperature and humidity through the PLC controller. The touch screen displays real-time data on ultraviolet absorption rate, infrared reflectance, VOCs concentration, water absorption rate and temperature difference. The data storage unit automatically generates a test report, which is compared with standard limits such as VOCs ≤ 50 g / L and ultraviolet absorption rate ≥ 95% to determine whether the coating performance meets the standards. According to the test requirements, the main control system can activate the first light module 5 and the second light module 6 individually or in combination to simulate different regional sunlight conditions.

[0146] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A low-VOCs UV-resistant heat-insulating coating composition, characterized in that, Composed of the following components in parts by weight: 30-45 parts water-based acrylic resin, 1-3 parts nitrogen-doped graphene, and nano-sized... 2-5 parts of composite powder, 8-12 parts of low water absorption and expansion glass microspheres, 5-10 parts of silane coupling agent modified sepiolite, 0.5-1.5 parts of silane coupling agent KH560, 0.5-0.7 parts of ultraviolet absorber UV-9, and 0.2-0.5 parts of hydroxyethyl cellulose thickener; The composition satisfies the following conditions: (1) VOCs content ≤ 50g / L; (2) Ultraviolet absorption rate ≥95%; (3) Infrared reflectivity ≥ 90%; (4) Coating water absorption rate ≤2%; The low water absorption and swelling glass microspheres are Poraver® X type glass microspheres with a particle size distribution of 10-50 μm, a true density of 0.2-0.6 g / cm³, and a water absorption and swelling rate of ≤0.5%. The nano In the composite powder, the mass ratio of indium tin oxide (ITO) to SiO2 is 1:2-1:4, the powder particle size is 20-50 nm, and the visible light transmittance is ≥80%. The preparation method of the silane coupling agent modified sepiolite is as follows: sepiolite powder and KH560 are mixed at a mass ratio of 10:1, ultrasonically treated at 60°C for 30 min, and dried to obtain modified sepiolite. The mass ratio of the ultraviolet absorber UV-9 to nitrogen-doped graphene is 1:3 to 1:

5.

2. The low-VOCs UV-resistant heat-insulating coating composition according to claim 1, characterized in that, The method for preparing the coating composition includes the following steps: (1) Premixing: The water-based acrylic resin, deionized water, and silane coupling agent KH560 are stirred at 600 r / min for 10 min; (2) Dispersion: Nitrogen-doped graphene and nano ITO-SiO2 composite powder were added and subjected to ultrasonic treatment at 40kHz for 30min. The power density of ultrasonic treatment was 0.5-0.8W / mL and the temperature was controlled at 25-35℃. (3) Blending: Add Poraver®X glass microspheres and modified sepiolite, and shear at high speed at 2000 r / min for 20 min; (4) Conditioning: Add UV absorber UV-9 and hydroxyethyl cellulose, and stir at 400 r / min until uniform; (5) Filtration: Pass through a 200-mesh sieve to obtain the finished coating.

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