Bio-based multimodal crystalline particle reflective thermal barrier waterproofing coating, additives, and methods of making

Abstract

The application discloses a bio-based multimodal crystalline particle reflective thermal insulation waterproof coating, an additive and a preparation method, and belongs to the technical field of building chemical materials and green energy-saving coating. The system is prepared from an organic silicon modified acrylic emulsion as a base material, a specific pigment composition, hollow glass microbeads, bio-based hydrophobic multimodal crystalline particles, an additive and water. The core of the application is to introduce polyhydroxy aliphatic acid ester powder with multimodal particle size distribution and high crystallinity, and to construct a weather-resistant protective layer on the surface through dry process synergistic pretreatment of a hindered amine light stabilizer, an ultraviolet absorber and nano zinc oxide. The coating realizes the unity of environmental protection and long-term performance: not only has excellent dense waterproof and mechanical performance, but also realizes excellent high-temperature anti-leveling characteristics through the construction of stable surface micro-morphology. The weather-resistant layer and the thermal insulation system are deeply synergistic, which greatly improves the anti-aging ability of the coating, and endows the coating with persistent high solar reflectance characteristics and excellent dust resistance and stain resistance.

Description

Technical Field

[0001] This invention belongs to the field of building chemical materials and green energy-saving coating technology, specifically relating to bio-based multi-peak crystalline particle reflective heat-insulating and waterproof coatings, additives and preparation methods. Background Technology

[0002] High-reflectivity coatings for cool roofs and building envelopes can effectively reduce roof temperature rise and building cooling load by increasing solar reflection and reducing heat absorption. Several similar technical approaches have emerged regarding reflective, insulating, and waterproof coatings for buildings.

[0003] Domestically, one type of technology mainly uses water-based acrylic, styrene-acrylic, or silicone-acrylic emulsions as film-forming base materials, combined with rutile titanium dioxide (TiO2), hollow glass microspheres, hollow ceramic microspheres, and mineral fillers to construct a reflective heat-insulating and waterproof system. For example, Chinese patent CN101709193A, "Water-based Acrylic Waterproof and Heat-insulating Coating," discloses a waterproof and heat-insulating coating prepared using elastic acrylate copolymer emulsion, ethylene-vinyl acetate copolymer emulsion (VAE), and organosilicon waterproof material cold-mixed copolymer emulsion as base materials, combined with hollow glass microspheres, hollow ceramic microspheres, TiO2, etc. While this technology balances waterproofing and heat insulation, it also points out that the elastic acrylate copolymer emulsion suffers from severe tackiness in summer. Chinese patent CN101665648B, "A Method for Preparing a Heat-Reflective and Heat-Insulating Coating," discloses the preparation of a heat-reflective and heat-insulating coating by adding heat-reflective nanopowder slurry and heat-insulating powder slurry to organosilicon-modified styrene-acrylic emulsion. Chinese patent CN101712835A, "Insulating Glass Microsphere Heat-Reflective Coating," discloses a surface / bottom layer reflective heat-insulating system composed of silicone-acrylic emulsion, rutile TiO2, and hollow glass microspheres. Chinese patent CN105969021B, "A Reflective Heat-Insulating and Hydrophobic Coating," discloses a coating system that combines reflective heat insulation and hydrophobic properties, constructed from acrylic elastic emulsion, insulating glass microspheres, and a hydrophobic self-cleaning agent.

[0004] Internationally, one type of technology focuses on near-infrared (NIR) reflective black pigments or cool-toned dark coatings. For example, EP2500317A1, "Infrared reflective black pigment, coating material using the infrared reflective black pigment, and resin composition," discloses NIR reflective black pigments based on composite oxides of elements such as Fe, Mn, Mg, Al, Ca, Si, Sr, and Ba, which can be used in heat-insulating coatings or resin compositions; US8822025B2, "Coating system exhibiting cool dark color," discloses a cool-toned dark coating system constructed by layering an infrared reflective layer with a radiation-absorbing layer. Another type of technology focuses on the application of bio-based polyhydroxyalkanoates (PHA) in coatings. For example, US10590289B2, "Use of polyhydroxyalkanoates as additives in coating compositions," discloses the use of PHA as a matting or smoothing additive in coatings to improve matting efficiency, flowability, scratch resistance, and anti-blocking properties.

[0005] Furthermore, the literature "Effects of soiling and cleaning on the reflectance and solar heat gain of a light-colored roofing membrane" points out that the reflectance of light-colored roofing materials with high initial solar reflectance can decrease significantly after the accumulation of smoke, dust, and biomass pollution. The literature "Effects of natural soiling and weathering on cool roof energy savings for dormitory buildings in Chinese cities with hot summers" points out that the retention of pollutants such as smoke, dust, salt, and biological growth during outdoor exposure of high-reflectance roofs is an important reason for the decrease in solar reflectance.

[0006] However, the aforementioned domestic and international technical approaches still have the following main shortcomings: First, most existing reflective heat-insulating and waterproof coatings rely on a combination of emulsions, TiO2, hollow microspheres, and conventional hydrophobic additives. Although they can achieve high initial reflection or heat insulation effects, they are not specifically designed to address the surface stickiness, thermal re-stickiness, and softening and leveling problems of low glass transition temperature (Tg) waterproof film-forming systems under high-temperature conditions, and are difficult to suppress the deposition of contaminant films and the decay of solar reflectance index (SRI) in the long term. Second, existing NIR reflective black pigment or cool-colored dark coating technologies mainly focus on pigment spectral reflectance design, and do not adequately consider the synergistic construction of stain-resistant and heat-leveling-resistant surface microstructures with water-based waterproof film-forming systems. Thirdly, the current application of PHA in coatings is mostly focused on conventional additive functions such as matting, improving feel, or scratch resistance. There is no technical solution that uses PHA particles with specific multi-peak particle size structure and high crystallinity as microstructural units on the surface of building reflective thermal insulation and waterproof coatings, and improves particle thermal morphology stability and outdoor weather resistance by synergistic surface loading of hindered amine light stabilizers (HALS), ultraviolet absorbers (UVA), and inorganic ultraviolet shielding agents. Fourthly, although existing technologies have recognized that pollution and aging will weaken the long-term performance of high-reflectivity roofs, there is a lack of a comprehensive technical system that takes into account bio-based, weather resistance, stain resistance, high-temperature anti-leveling, and long-term SRI maintenance.

[0007] In summary, under the macro trend of building energy conservation and emission reduction and green and low-carbon development, developing a new generation of building reflective thermal insulation and waterproof coating systems that balance ecological environmental protection and long-term service performance has become an objective requirement for technological evolution in this field. In the future, it is expected that by scientifically introducing renewable bio-based polymer materials and deeply utilizing their microscopic crystalline morphology and multi-dimensional synergistic modification of surface weather resistance, a feasible path can be provided to overcome the technical bottlenecks of traditional water-based low-Tg waterproofing systems in terms of high-temperature stickiness and long-term staining degradation. Objectively speaking, exploring and constructing a comprehensive solution with durable UV aging resistance, high-temperature leveling resistance, and long-term maintenance of Solar Reflectance Index (SRI) will not only help overcome engineering pain points under harsh outdoor conditions and solidify the long-term energy-saving benefits of high-reflectivity roofing systems, but will also provide positive technological prospects for the high-value-added application of green and environmentally friendly building materials. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a bio-based multi-peak crystalline particle reflective heat-insulating and waterproof coating, additives, and preparation method. Specifically, the bio-based multi-peak crystalline particle reflective heat-insulating and waterproof coating, by weight, comprises the following components: an aqueous film-forming base material is an organosilicon-modified acrylic emulsion, in parts from 20 to 75 parts by solids content, for example, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, 39.5 parts, 40 parts, 42 parts, 45 parts, 48 ​​parts, 50 parts, 52 parts, 55 parts, etc. The dosage is 5 to 45 parts, for example, 5, 6, 60, 62, 65, 68, 70, 72, or 75 parts; the reflective component is a pigment composition composed of rutile titanium dioxide and near-infrared reflective black composite metal oxide pigment, and the dosage is 5 to 45 parts, for example, 5, 6, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30, 32, 35, 38, 40, 42, or 45 parts; the heat-insulating filler is hollow glass microspheres, and the dosage is 0.5 to 30 parts, for example... For example, the amounts can be 0.5 parts, 0.8 parts, 1 part, 1.5 parts, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, or 30 parts; bio-based hydrophobic multi-peak crystalline particles can be 3 to 20 parts, for example, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 18 parts, or 20 parts; functional additives can be 0.1 to 12 parts, for example, 0.1 parts, 0.2 parts, 0.5 parts, or 0.5 parts. 0.8, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0 or 12 parts; water 5 to 45 parts, for example, 5, 6, 8, 10, 12, 15, 16, 18, 20, 21, 22, 24, 26, 28, 30, 32, 35, 38, 40, 42 or 45 parts.

[0009] The bio-based hydrophobic multimodal crystalline particles are polyhydroxyalkanoate (PHA) crystalline polyester particles derived from renewable resource monomers and added in solid powder form. They are obtained by compounding coarse and fine particle fractions that have undergone annealing and crystallization treatment, followed by hydrophobication treatment of the fatty acid or fatty acid salt surface. In the coating film formed by the paint, they exist as a particulate dispersion phase that does not form a continuous film. The PHA matrix portion of the PHA crystalline polyester particles is the PHA bulk; the coarse particle fraction forms a coarse particle group, and the fine particle fraction forms a fine particle group. The bio-based hydrophobic multimodal crystalline particles have a multimodal particle size distribution and include both coarse and fine particle groups. The paint contains anti-UV aging components, including hindered amine light stabilizer (HALS), ultraviolet absorber (UVA), and nano-zinc oxide. After dry pretreatment with HALS, UVA, and nano-zinc oxide, a weather-resistant protective layer is formed on the particle surface of the bio-based hydrophobic multimodal crystalline particles. The mass ratio of HALS to UVA in the weather-resistant protective layer is from 0.5:1 to 8:6, for example, it can be 0.5:1, 11:20, 3:5, 13:20, 2:3, 7:10, 3:4, 4:5, 9:10, 1:1, 11:10, 6:5, 5:4, 4:3 or 8:6. The amount of the weather-resistant protective layer, based on the dry basis mass of the bio-based hydrophobic multimodal crystalline particles, is from 0.8% to 2.5%, for example, it can be 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4% or 2.5%. The mass ratio of the bio-based hydrophobic multimodal crystalline particles to the aqueous film-forming matrix, based on solid content, is from 0.05 to 0.60, for example, it can be 0.050, 0.060, 0.071, 0.080, 0.100, 0.120, 0.150, 0.180, 0.203, 0.220, 0.250, 0.267, 0.300, 0.350, 0.400, 0.450, 0.500, 0.550, 0.571, or 0.60. 0; and the morphology retention rate of the bio-based hydrophobic multi-peak crystalline particles at 80℃ is above 90%, for example, it can be 90.0%, 90.5%, 91.0%, 91.5%, 92.0%, 92.5%, 93.0%, 93.5%, 94.0%, 94.5%, 95.0%, 95.5%, 96.0%, 96.5%, 97.0%, 97.5%, 98.0%, 98.5%, 99.0%, 99.5% or 100%.The test method for the morphology retention rate of particles at 80℃ is as follows: bio-based hydrophobic multi-peak crystalline particles or their additives are spread evenly in a glass dish and placed in an 80℃ forced-air oven for 2 hours. After cooling to room temperature, the coarse and fine particle groups are observed and counted under a microscope. Particles with intact edges, no mutual fusion, and whose average equivalent circle diameter changes by no more than 15% compared with the untreated control sample are judged as particles with complete outlines. The morphology retention rate is calculated as the percentage ratio of the total number of particles with complete outlines to the total number of counted particles.

[0010] The volume-weighted average particle size of the coarse particle group is from 8 μm to 30 μm, for example, it can be 8.0 μm, 8.5 μm, 9.0 μm, 9.5 μm, 10.0 μm, 10.5 μm, 11.0 μm, 11.4 μm, 12.0 μm, 12.6 μm, 13.0 μm, 13.8 μm, 14.5 μm, 15.2 μm, 16.0 μm, 16.8 μm, 18 μm. The particle sizes are 0 μm, 18.5 μm, 20.0 μm, 22.0 μm, 25.0 μm, 28.0 μm, or 30.0 μm; the volume-weighted average particle size of the fine particle group is from 0.10 μm to 1.2 μm, for example, it can be 0.10 μm, 0.12 μm, 0.15 μm, 0.18 μm, 0.20 μm, 0.25 μm, 0.28 μm, 0.30 μm, or 0.33 μm. The particle sizes are 0.35μm, 0.40μm, 0.41μm, 0.45μm, 0.48μm, 0.50μm, 0.60μm, 0.70μm, 0.80μm, 0.90μm, 1.00μm, 1.10μm, or 1.20μm; and the mass ratio of the coarse particle group to the fine particle group is 60:40 to 85:15, for example, it can be 60:40, 61:39, 62... :38, 63:37, 64:36, 65:35, 66:34, 67:33, 68:32, 69:31, 70:30, 71:29, 72:28, 73:27, 74:26, 75:25, 76:24, 77:23, 78:22, 79:21, 80:20, 81:19, 82:18, 83:17, 84:16 or 85:15. The PHA bulk of the bio-based hydrophobic multimodal crystalline particles has a crystallinity of 40% to 70%, for example, it can be 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 52%, 54%, 55%, 56%, 58%, 60%, 62%, 64%, 65%, 66%, 68%, or 70%, and the crystallinity of the PHA bulk is measured using differential scanning calorimetry. The main melting peak temperature during the secondary heating should not be lower than 150℃, for example, it can be 150.0℃, 150.6℃, 151.1℃, 152.0℃, 153.0℃, 155.0℃, 155.4℃, 158.0℃, 160.0℃, 161.2℃, 165.0℃, 168.4℃, 169.1℃, 170.0℃, 171.5℃, 172.8℃, 175.0℃, or 176.2℃.

[0011] The particle size distribution of the bio-based hydrophobic multimodal crystalline particles, measured by laser particle size distribution method, satisfies: D 10The micrometer size is from 0.10 to 0.25 μm, for example, it can be 0.10 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm, 0.15 μm, 0.16 μm, 0.17 μm, 0.18 μm, 0.19 μm, 0.20 μm, 0.21 μm, 0.22 μm, 0.23 μm, 0.24 μm, or 0.25 μm; D 50 6 to 10 μm, for example, 6.0 μm, 6.2 μm, 6.5 μm, 6.8 μm, 7.0 μm, 7.2 μm, 7.5 μm, 7.8 μm, 8.0μm, 8.2μm, 8.5μm, 8.8μm, 9.0μm, 9.2μm, 9.4μm, 9.6μm, 9.8μm or 10.0μm; D 90 The value is 25 to 35 μm, for example, it can be 25.0 μm, 25.6 μm, 26.0 μm, 26.5 μm, 27.0 μm, 27.5 μm, 28.0 μm, 28.5 μm, 29.0 μm, 29.5 μm, 30.0 μm, 30.2 μm, 31.0 μm, 31.5 μm, 32.0 μm, 32.5 μm, 33.0 μm, 33.8 μm, 34.0 μm, 34.5 μm, 34.8 μm, or 35.0 μm; and the volume distribution curve has a value between 0.25 and 0.50 μm, for example, it can be 0.25 μm, 0.26 μm, 0.28 μm, 0.30 μm, 0. The two peak values ​​are 32μm, 0.33μm, 0.35μm, 0.38μm, 0.40μm, 0.41μm, 0.42μm, 0.45μm, 0.46μm, 0.48μm or 0.50μm, and 8 to 13μm, for example, can be 8.0μm, 8.2μm, 8.4μm, 8.6μm, 9.0μm, 9.4μm, 9.8μm, 10.0μm, 10.5μm, 11.0μm, 11.5μm, 12.0μm, 12.2μm, 12.5μm, 12.8μm, 12.9μm or 13.0μm; and the coating film formed by the coating has an 80°C softening leveling grade of 0. The test method for the softening leveling grade is as follows: After the coating is made into a film and cured, it is placed in an 80℃ forced-air oven for 2 hours. After cooling to room temperature, it is covered with a transparent grid film for observation. If there are no continuous bright flow marks and the surface particles are basically intact, it is rated as grade 0.

[0012] The HALS is a hindered amine light stabilizer of the 2,2,6,6-tetramethylpiperidine derivative class, the UVA is a benzotriazole ultraviolet absorber, and the nano-zinc oxide serves as an inorganic ultraviolet shielding agent; the surface retention rate of the ultraviolet absorber of the bio-based hydrophobic multimodal crystalline particles is not less than 82%, for example, it can be 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%; the test method for this surface retention rate is as follows: take a test sample... The sample was added to anhydrous ethanol and stirred for extraction. After centrifugation and filtration, the supernatant was taken and the absorbance was measured to calculate the extraction amount. The surface retention rate was calculated as the percentage of the initial amount of UV absorber added minus the extraction amount to the initial amount added. The mass fraction of the nano zinc oxide was 10% to 60% based on the total mass of the weather-resistant protective layer, for example, it could be 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48%, 50%, 52%, 55%, 58%, or 60%.

[0013] The PHA in the polyhydroxy fatty acid ester crystalline polyester particles is selected from one or more of short-chain polyhydroxy fatty acid esters, medium- and long-chain polyhydroxy fatty acid esters, or copolymers of the above polyhydroxy fatty acid esters.

[0014] The short-chain polyhydroxy fatty acid ester is selected from one or more of poly(3-hydroxybutyrate), poly(4-hydroxybutyrate), poly(3-hydroxyvalerate), poly(3-hydroxybutyrate-3-hydroxyvalerate copolyester), and poly(3-hydroxybutyrate-4-hydroxybutyrate copolyester;

[0015] The medium- and long-chain polyhydroxy fatty acid esters are selected from one or more of poly(3-hydroxyhexanoate), poly(3-hydroxyheptanoate), poly(3-hydroxyoctanoate), poly(3-hydroxynonanoate), poly(3-hydroxydecanoate), poly(3-hydroxyundecanoate), poly(3-hydroxydodecanate), poly(3-hydroxytetrate), poly(3-hydroxytetradecanoate), and poly(3-hydroxybutyrate-3-hydroxyhexanoate) copolyester; the bio-based hydrophobic multimodal crystalline particles are obtained by surface treatment of the PHA crystalline polyester particles with fatty acids or fatty acid salts; the functional additives include one or more of dispersants, wetting agents, defoamers, leveling agents, thickeners, anti-settling agents, preservatives, bactericides, freeze-thaw stabilizers, film-forming aids, crosslinking agents, and coupling agents.

[0016] The aqueous film-forming base material is a silicone-modified acrylic emulsion, which is pre-emulsified from butyl acrylate, methyl methacrylate, styrene, acrylic acid, and 3-methacryloyloxypropyltrimethoxysilane in a mass ratio of 34.0:12.0:3.0:1.0:0.8 and then emulsion polymerized at 78°C under an ammonium persulfate / sodium bisulfite initiation system; the mass ratio of rutile titanium dioxide to the near-infrared reflective black composite metal oxide pigment is 18:4.

[0017] This invention also provides a bio-based hydrophobic multi-peak crystalline particle additive for preparing the aforementioned coating. This is a solid powder additive comprising a coarse particle fraction treated with annealing and crystallization, a fine particle fraction treated with annealing and crystallization, and a weather-resistant protective layer formed on the surfaces of the coarse and fine particle fractions. Both the coarse and fine particle fractions are PHA particles obtained from renewable resource monomers and undergo surface hydrophobication treatment with fatty acids or fatty acid salts. The weather-resistant protective layer is formed by dry pretreatment with HALS, UVA, and nano-zinc oxide. The UV absorber surface retention rate of the bio-based hydrophobic multi-peak crystalline particles is not less than 82%, for example, it can be 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%. The mass ratio of HALS to UVA is from 0.5:1 to 8:6, for example, it can be 0.5:1, 11:20, 3:5, 13:20, 2:3, 7:10, 3:4, 4:5, 9:10, 1:1, 11:10, 6:5, 5:4, 4:3, or 8:6; the mass fraction of nano-zinc oxide is from 10% to 60% based on the total mass of the weather-resistant protective layer, for example, it can be 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%. The percentages are 38%, 40%, 42%, 45%, 48%, 50%, 52%, 55%, 58%, or 60%; the amount of the weather-resistant protective layer is 0.8% to 2.5% based on the total dry weight of the coarse and fine fractions, for example, it can be 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, or 2.5%.The bio-based hydrophobic multimodal crystalline particles comprise coarse and fine particle groups. The volume-weighted average particle size of the coarse particle group is 8 μm to 30 μm, for example, it can be 8.0 μm, 8.5 μm, 9.0 μm, 9.5 μm, 10.0 μm, 10.5 μm, 11.0 μm, 11.4 μm, 12.0 μm, 12.6 μm, 13.0 μm, 13.8 μm, 14.5 μm, 15.2 μm. The particle sizes are 16.0 μm, 16.8 μm, 18.0 μm, 18.5 μm, 20.0 μm, 22.0 μm, 25.0 μm, 28.0 μm, or 30.0 μm; the volume-weighted average particle size of the fine particle group is 0.10 μm to 1.2 μm, for example, it can be 0.10 μm, 0.12 μm, 0.15 μm, 0.18 μm, 0.20 μm, 0.25 μm, 0.28 μm, 16.0 μm, 16.8 μm, 18.0 μm, 18.5 μm, 20.0 μm, 22.0 μm, 25.0 μm, 28.0 μm, or 30.0 μm; The particle sizes are 0.30 μm, 0.33 μm, 0.35 μm, 0.40 μm, 0.41 μm, 0.45 μm, 0.48 μm, 0.50 μm, 0.60 μm, 0.70 μm, 0.80 μm, 0.90 μm, 1.00 μm, 1.10 μm, or 1.20 μm; the mass ratio of the coarse particle group to the fine particle group is 60:40 to 85:15, for example, it can be 60:40, 61... The particle size distribution of the bio-based hydrophobic multimodal crystalline particles, measured by laser particle size distribution method, satisfies: D. (The values ​​are 39, 62:38, 63:37, 64:36, 65:35, 66:34, 67:33, 68:32, 69:31, 70:30, 71:29, 72:28, 73:27, 74:26, 75:25, 76:24, 77:23, 78:22, 79:21, 80:20, 81:19, 82:18, 83:17, 84:16, or 85:15.) 10 The micrometer size is from 0.10 to 0.25 μm, for example, it can be 0.10 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm, 0.15 μm, 0.16 μm, 0.17 μm, 0.18 μm, 0.19 μm, 0.20 μm, 0.21 μm, 0.22 μm, 0.23 μm, 0.24 μm, or 0.25 μm; D 50 6 to 10 μm, for example, 6.0 μm, 6.2 μm, 6.5 μm, 6.8 μm, 7.0 μm, 7.2 μm, 7.5 μm, 7.8 μm, 8.0μm, 8.2μm, 8.5μm, 8.8μm, 9.0μm, 9.2μm, 9.4μm, 9.6μm, 9.8μm or 10.0μm; D 90The thickness is 25 to 35 μm, for example, it can be 25.0 μm, 25.6 μm, 26.0 μm, 26.5 μm, 27.0 μm, 27.5 μm, 28.0 μm, 28.5 μm, 29.0 μm, 29.5 μm, 30.0 μm, 30.2 μm, 31.0 μm, 31.5 μm, 32.0 μm, 32.5 μm, 33.0 μm, 33.8 μm, 34.0 μm, 34.5 μm, 34.8 μm, or 35.0 μm; and the volume distribution curve has a thickness between 0.25 and 0.50 μm, for example, it can be 0.25 μm, 0.26 μm, 0.28 μm, or 0.50 μm. μm, 0.30 μm, 0.32 μm, 0.33 μm, 0.35 μm, 0.38 μm, 0.40 μm, 0.41 μm, 0.42 μm, 0.45 μm, 0.46 μm, 0.48 μm or 0.50 μm, and 8 to 13 μm, for example, it may be 8.0 μm, 8. Two peaks of 2μm, 8.4μm, 8.6μm, 9.0μm, 9.4μm, 9.8μm, 10.0μm, 10.5μm, 11.0μm, 11.5μm, 12.0μm, 12.2μm, 12.5μm, 12.8μm, 12.9μm or 13.0μm. The pHA bulk of the bio-based hydrophobic multimodal crystalline particles has a crystallinity of 40% to 70%, for example, it can be 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 52%, 54%, 55%, 56%, 58%, 60%, 62%, 64%, 65%, 66%, 68%, or 70%; the pHA bulk density is measured using differential scanning calorimetry. The main melting peak temperature during the secondary heating should not be lower than 150℃, for example, it can be 150.0℃, 150.6℃, 151.1℃, 152.0℃, 153.0℃, 155.0℃, 155.4℃, 158.0℃, 160.0℃, 161.2℃, 165.0℃, 168.4℃, 169.1℃, 170.0℃, 171.5℃, 172.8℃, 175.0℃, or 176.2℃.

[0018] Furthermore, the present invention provides a method for preparing the aforementioned coating, comprising the following steps:

[0019] Pretreatment step: Annealed and crystallized bio-based hydrophobic multimodal crystalline particles treated with fatty acids or fatty acid salts for surface hydrophobization are mixed with HALS, UVA, and nano-zinc oxide at 40°C to 80°C, for example, 40°C, 42°C, 45°C, 48°C, 50°C, 52°C, 55°C, 58°C, 60°C, 62°C, 65°C, 68°C, 70°C, 72°C, 75°C, 78°C, or 80°C for 3 min to 20 min, for example, 3 min, 4 min, 5 min, 6 min, 8 min, or 1 min. The weather-resistant particles are obtained after processing for 0 min, 12 min, 14 min, 15 min, 16 min, 18 min, or 20 min, so that the HALS, UVA, and nano zinc oxide are jointly attached to the particle surface to form a weather-resistant protective layer; wherein the mass ratio of HALS to UVA is 0.5:1 to 8:6, the mass fraction of nano zinc oxide is 10% to 60% based on the total mass of the weather-resistant protective layer, and the amount of the weather-resistant protective layer is 0.8% to 2.5% based on the dry basis mass of the bio-based hydrophobic multi-peak crystalline particles;

[0020] Step 1: Mix water, dispersant, and reflective component, and shear disperse at 1200 to 3000 r / min, for example, 1200 r / min, 1300 r / min, 1400 r / min, 1500 r / min, 1600 r / min, 1800 r / min, 2000 r / min, 2200 r / min, 2400 r / min, 2600 r / min, 2800 r / min, or 3000 r / min for 5 to 30 minutes, for example, 5 minutes, 6 minutes, 8 minutes, 10 minutes, 12 minutes, 14 minutes, 15 minutes, 18 minutes, 20 minutes, 22 minutes, 25 minutes, 28 minutes, or 30 minutes. The fineness measured according to GB / T1724-2019 should be ≤40 μm to obtain reflective slurry. The dispersion medium is water.

[0021] Step 2: Add the reflective slurry obtained in Step 1 to the aqueous film-forming base material while stirring at 200 to 800 r / min, for example, 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, 550 r / min, 600 r / min, 700 r / min or 800 r / min, and mix for 5 to 15 minutes, for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes or 15 minutes, to obtain the film-forming base material mixed slurry;

[0022] Step 3: Add the heat insulation filler to the film-forming base material mixture obtained in Step 2 under stirring at 100 to 400 r / min, for example, 100 r / min, 120 r / min, 150 r / min, 180 r / min, 200 r / min, 220 r / min, 250 r / min, 280 r / min, 300 r / min, 350 r / min or 400 r / min, and mix for 5 to 15 minutes, for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes or 15 minutes, to obtain the heat insulation filler mixture base material;

[0023] Step 4: Add the weather-resistant particles obtained in the pretreatment step to the heat-insulating filler mixture base slurry obtained in Step 3 at a speed of 150 to 600 r / min, for example, 150 r / min, 180 r / min, 200 r / min, 220 r / min, 250 r / min, 280 r / min, 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, 550 r / min or 600 r / min. Control the system temperature not to exceed 50℃, for example, 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 48℃ or 50℃, and disperse for 10 to 40 min, for example, 10 min, 12 min, 14 min, 15 min, 18 min, 20 min, 22 min, 25 min, 28 min, 30 min, 35 min or 40 min, to obtain a particle dispersion coating.

[0024] Step 5: Add thickener, wetting agent, defoamer, leveling agent, preservative and film-forming aid to the particle dispersion coating obtained in Step 4, stir for 10 to 20 minutes, for example 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 18 minutes or 20 minutes, then filter and package to obtain the finished coating; the finished coating obtained in Step 5 shall have an application viscosity of 70 KU to 130 KU at 25℃ according to GB / T9269-2009, for example 70 KU, 72 KU, 75 KU, 78 KU, 80 KU, 84 KU, 88 KU, 90 KU, 92 KU, 96 KU, 100 KU, 102 KU, 105 KU, 109 KU, 112 KU, 118 KU, 120 KU, 125 KU or 130 KU.

[0025] Compared with the prior art, the use of this invention can achieve the following significant beneficial effects:

[0026] Stable long-lasting reflectivity and anti-fouling performance: This invention, through the rational ratio of rutile titanium dioxide and near-infrared reflective black composite metal oxide pigments, combined with multi-peak crystalline PHA particles with specific particle size structure, significantly reduces dust adhesion and pollutant deposition under 2000h xenon arc aging and 80℃ artificial pollution dust conditions, thereby maintaining a high solar reflectance index (SRI).

[0027] Excellent high-temperature resistance to leveling and structure retention: PHA multi-peak crystalline particles with high crystallinity and a main melting peak temperature of not less than 150℃ are selected to construct the microstructure of the coating surface. Combined with surface hydrophobic modification, the coating film can still maintain a complete raised contour under high-temperature conditions of 80℃, successfully avoiding the defects of softening and re-sticking and leveling in traditional waterproofing systems in summer.

[0028] Significant resistance to UV aging and weathering: An innovative dry-process synergistic pretreatment of crystalline particles using hindered amine light stabilizers, UV absorbers, and nano-zinc oxide forms a tightly coated, weather-resistant protective layer on the particle surface. This treatment greatly improves the UV blocking rate of both the particles themselves and the overall coating, significantly delaying the photoaging process.

[0029] Excellent waterproof and comprehensive mechanical properties: While taking into account reflective heat insulation and surface micromorphological stability, the coating still has good elongation at break, tensile strength, excellent static water contact angle and impermeability, and extremely low total fluorine content, which fully meets the stringent standards of green energy-saving and high weather-resistant building materials. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the microstructure of the bio-based multi-peak crystalline particle reflective heat-insulating and waterproof coating described in this invention.

[0031] In the figure, 1-coating; 2-particulate dispersed phase; 3-aqueous film-forming base material; 4-coarse particle group; 5-fine particle group; 6-hollow glass microspheres; 7-reflective component. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention. Unless otherwise stated, the raw materials used in this embodiment are commercially available industrial products or can be prepared by conventional methods. Unless otherwise specified, performance testing methods are performed according to the standards described in the invention summary section.

[0033] Figure 1A schematic diagram of the microstructure of a bio-based multi-peak crystalline particle reflective thermal insulation and waterproof coating is provided, clearly showing the microstructure of the coating film 1 formed by the coating on a substrate. The coating film 1 contains a particulate dispersion phase 2 and an aqueous film-forming base material 3. The particulate dispersion phase 2 includes coarse particle groups 4 and fine particle groups 5, and is distributed in the coating film 1 together with hollow glass microspheres 6 and reflective components 7.

[0034] The present invention will be further described below with reference to embodiments and comparative examples, but the present invention is not limited to the following embodiments.

[0035] Unless otherwise specified, all "parts" below refer to parts by weight; water-based film-forming base materials are converted to parts by weight based on solid content. When actually adding materials, the wet material addition amount is calculated based on the emulsion solid content, and the amount of deionized water added is deducted accordingly. All percentages of formulation composition, addition amount, and content below, except for crystallinity, UVA surface retention rate, SRI retention rate, morphology retention rate, relative humidity, and other specified terms, are all percentages by weight. 10 D 50 D 90Peak positions 1 and 2 were determined using a Mastersizer 3000 laser particle size analyzer (listed in Table 2) according to ISO 13320:2020 for the mixed bio-based hydrophobic multi-peak crystalline particles or their additives. A dry dispersion unit was used with a dispersion pressure of 2.0 bar and an injection rate of 50%. Each sample was measured three times consecutively, and the average value was taken. The Mie model was used as the optical model, with a particle refractive index of 1.47 and an absorptivity of 0.01. Peak positions 1 and 2 were obtained by fitting a double log-normal distribution function to the volume distribution curve of the mixed sample using Origin 2024 software, with a coefficient of determination R² of not less than 0.995. The peak sizes of the two peaks were denoted as peak position 1 and peak position 2, respectively. The average particle size of both the coarse and fine particle groups is expressed as a volume-weighted average particle size. The coarse and fine particle fractions before mixing were measured separately under the same conditions as the laser particle size distribution test described above. The mass ratio of the coarse to fine particle groups was calculated based on the actual mass of the mixed feed. The amount of weather-resistant protective layer is based on the dry weight of the bio-based hydrophobic multi-peak crystalline particles, and the mass fraction of the inorganic UV shielding agent is based on the total mass of the weather-resistant protective layer. The main melting peak temperature and crystallinity of the particle bulk were determined using the DSC two-stage heating method. Unless otherwise specified, the crystallinity and main melting peak temperature mentioned in this specification refer to the thermal parameters of the polyhydroxyalkanoate bulk of the bio-based hydrophobic multi-peak crystalline particles, excluding the surface hydrophobic modifier and the weather-resistant protective layer. DSC testing was conducted under a nitrogen atmosphere at a flow rate of 50 mL / min. The sample mass was 5.0 ± 0.5 mg, and an aluminum crucible was used for sealing. The test procedure was as follows: temperature was increased from 25 °C to 200 °C, held for 3 min, then decreased to -20 °C at a rate of 10 °C / min, and then increased to 200 °C at a rate of 10 °C / min. For single-component particles, the crystallinity was calculated using the main melting peak temperature and enthalpy of fusion from the second heating curve.

[0036] The crystallinity of single particles of PHB, PHBV, and P34HB are respectively determined by X c,i =ΔH m,i / ΔH m,ref,i Calculate by multiplying by 100%, where ΔH m,ref,PHB =146.0 J / g, ΔH m,ref,PHBV =142.0 J / g, ΔH m,ref,P34HB =110.0 J / g;

[0037] For mixed particles composed of two types of PHA particles, the main melting peak temperature is directly measured on the bulk sample of the mixed particles, and the crystallinity is determined according to the X value of each individual particle constituting the mixed particles under the same DSC conditions. c,i Combined with its quality fraction by X c =Σ(w i ×X c,i Weighted calculation, where w i For the firsti The mass fraction of a single particle.

[0038] Unless otherwise specified, the experimental environment was a temperature of 23±2℃ and a relative humidity of 50±5%.

[0039] Main reagents and raw materials

[0040] Table 1 Main Reagents and Raw Materials

[0041]

[0042] The PHB, PHBV, and P34HB listed in Table 1 are all commercially available bio-based PHA resins, which are polyhydroxyalkanoate materials derived from renewable resource monomers, and are the specific raw materials for the implementation of "PHA derived from renewable resource monomers" in this specification.

[0043] Main analytical and testing instruments and software

[0044] Table 2 Main analytical instruments and software

[0045]

[0046] Main testing standards and testing methods

[0047] Unless otherwise specified, all centrifugation steps were performed in a Sigma 3-18KS refrigerated centrifuge with an effective rotor radius of 8.5 cm; 3000 r / min corresponds to 850 × g, and 8000 r / min corresponds to 6080 × g.

[0048] Coating preparation and sample curing: Before use, the obtained coating was slowly stirred at 300 r / min for 5 min to eliminate localized settling and stratification that occurred during transportation or standing. The coating was applied using a wire-bar coating method to the surfaces of 150 mm × 75 mm × 4 mm asbestos-free fiber cement boards and 150 mm × 75 mm × 2 mm PTFE release liner boards, with the wet film thickness controlled at 800 ± 20 μm. Six fiber cement board samples and three PTFE release liner samples were prepared for each sample. Of the fiber cement board samples, three were used for initial SRI and SRI testing after 2000 h xenon arc aging, and the other three were used for dust accumulation at 80℃, stain resistance rating, and SRI testing after rinsing. The PTFE release liner samples, after curing, were peeled off to form a free film, which was used for tensile, contact angle, water resistance, and total fluoride testing. All samples were cured at 23±2℃ and 50±5% relative humidity for 7 days. After curing, they were numbered, sealed and stored, and rebalanced in the same environment for 24 hours before testing.

[0049] Particle size distribution and D 10 D 50 D 90The determination was performed according to ISO 13320:2020, "Particle size analysis—Laser diffraction methods". D 10 D 50 D 90 Peak positions 1 and 2 were determined using a Mastersizer 3000 laser particle size analyzer (listed in Table 2) according to ISO 13320:2020 for the mixed bio-based hydrophobic multi-peak crystalline particles or their additives. A dry dispersion unit was used with a dispersion pressure of 2.0 bar and an injection rate of 50%. Each sample was measured three times consecutively, and the average value was taken. The Mie model was used as the optical model, with a particle refractive index of 1.47 and an absorptivity of 0.01. Peak positions 1 and 2 were obtained by fitting a double log-normal distribution function to the volume distribution curve of the mixed sample using Origin 2024 software, with a coefficient of determination R² of not less than 0.995. The peak sizes of the two peaks were denoted as peak position 1 and peak position 2, respectively. The average particle size of both the coarse and fine particle groups is expressed as a volume-weighted average particle size. The coarse and fine particle fractions before mixing are measured separately under the same conditions as the laser particle size analysis. The mass ratio of the coarse to fine particle groups is calculated based on the actual mass of the mixed feed.

[0050] Main melting peak temperature, enthalpy of fusion, and crystallinity: determined according to ISO 11357-3:2025 "Plastics—Differential scanning calorimetry (DSC)—Part 3: Determination of temperature and enthalpy of melting and crystallization" and the DSC conditions specified in this specification. The main melting peak temperature and crystallinity of the particle bulk were determined using the DSC two-stage heating method. Unless otherwise specified, the crystallinity and main melting peak temperature mentioned in this specification refer to the thermal parameters of the polyhydroxyalkanoate bulk of the bio-based hydrophobic multi-peak crystalline particles, excluding the surface hydrophobic modifier and weather-resistant protective layer. DSC testing was conducted under a nitrogen atmosphere with a nitrogen flow rate of 50 mL / min and a sample mass of 5.0 ± 0.5 mg, using a sealed aluminum crucible. The test procedure was as follows: heating from 25°C to 200°C, holding for 3 min, then cooling to -20°C at 10°C / min, and then heating back to 200°C at 10°C / min. For single-component particles, the crystallinity is calculated using the main melting peak temperature and enthalpy of fusion from the second heating curve. The crystallinity of PHB, PHBV, and P34HB single particles is calculated according to X... c,i =ΔH m,i / ΔH m,ref,i Calculate by multiplying by 100%, where ΔH m,ref,PHB=146.0 J / g, ΔH m,ref,PHBV =142.0 J / g, ΔH m,ref,P34HB =110.0 J / g; For mixed particles composed of two types of PHA particles, the main melting peak temperature is directly measured on the bulk sample of the mixed particles, and the crystallinity is determined according to the X value of each individual particle constituting the mixed particles under the same DSC conditions. c,i Combined with its quality fraction by X c =Σ(w i ×X c,i Weighted calculation, where w i Let be the mass fraction of the i-th type of single particle.

[0051] Application viscosity: The viscosity was measured at 25°C using the digital display Stormer viscometer method in GB / T9269-2009 "Determination of viscosity of coatings - Stormer viscometer method". The KU-3 Stormer viscometer listed in Table 2 was used. Before the test, the sample was kept at 25°C for 2 hours and slowly stirred at 300 r / min for 5 minutes. The result is expressed as KU.

[0052] Artificial climate aging: conducted according to GB / T1865-2009 "Artificial climate aging and artificial radiation exposure to filtered xenon arc radiation for paints and varnishes". A Ci4400 xenon arc aging test chamber was used, with the irradiance set to (0.35±0.02) W / (m²·nm) (at 340nm), the blackboard temperature set to (65±3)℃, and the relative humidity inside the chamber set to (50±5)%; each cycle consisted of 18 minutes of pure water spraying and 102 minutes of light exposure, for a total of 2000 hours of aging.

[0053] Solar reflectance, hemispherical emissivity, SRI, post-rinsing SRI, and SRI retention rate after 2000h xenon arc aging: These were determined according to the methods specified in GB / T25261-2018 "Reflective Thermal Insulation Coatings for Buildings" and this instruction manual. After curing, fiber cement board samples were placed at 23±2℃ and 50±5% relative humidity for 24h, and then the solar reflectance and hemispherical emissivity were measured. Solar reflectance was measured using an ultraviolet-visible-near-infrared spectrophotometer with an integrating sphere in the 300nm to 2500nm wavelength range. Three different locations were tested for each sample, and the average value was taken. Hemispherical emissivity was measured using a surface emissivity meter at 23±2℃. Three different locations were tested for each sample, and the average value was taken. Initial SRI, post-aging SRI, and post-rinsing SRI were all calculated from solar reflectance and hemispherical emissivity according to the solar reflectance index calculation method specified in GB / T25261-2018. The initial SRI was measured on the unaged sample; the SRI retention rate after aging was calculated as "SRI after aging / initial SRI × 100%". The SRI after rinsing was measured using the same method after completing the stain resistance and 80℃ dust adhesion tests, rinsing with deionized water, and air drying.

[0054] Tensile strength and elongation at break: Tested according to GB / T16777-2008 "Test Methods for Waterproof Coatings for Buildings" and in accordance with the conditions specified in this instruction manual. The cured free membrane was cut into Type I dumbbell-shaped specimens with an effective gauge length of 25 mm and an effective narrow section width of 6 mm. Testing was conducted using an electronic universal testing machine at a tensile speed of 500 mm / min. Before testing, the thickness was measured at three points within the effective area of ​​the specimen using a digital thickness gauge, and the average value was taken. At least five effective specimens were required for each sample. Tensile strength was calculated by dividing the maximum tensile force by the initial effective cross-sectional area of ​​the specimen. Elongation at break was calculated as "increase in gauge spacing at break / initial gauge length × 100%". The final result was the arithmetic mean of the effective specimens.

[0055] Impermeability: Tested according to GB / T16777-2008 "Test Methods for Waterproof Coatings for Buildings". A fiber cement board sample cured for 7 days was placed in an impermeability tester with a test area of ​​100 cm². The test was conducted under a water pressure of (0.30 ± 0.01) MPa for 30 minutes. No water seepage, water droplets, or damp marks on the back side were recorded as "0.30 MPa, 30 min impermeable".

[0056] Static water contact angle: Refer to GB / T30693-2014 "Measurement of Water Contact Angle of Plastic Films" and conduct the test under the free membrane conditions specified in this instruction manual. Use the air contact surface as the test surface, and deionized water with a resistivity of not less than 18.2 MΩ·cm as the titrant. The volume of a single drop is 3.0 μL. After the droplet falls onto the membrane surface, allow it to stand for 5 seconds, read the left and right contact angles, and take the average value as the result for that measurement point. Take 3 free membrane samples for each sample, and test 3 different locations on each sample. Take the arithmetic mean of the 9 measurement points as the result for that sample.

[0057] Water resistance: Refer to GB / T9274-1988 "Determination of resistance to liquid media for paints and varnishes" and perform the test according to the free membrane immersion conditions specified in this instruction manual. Cut a 50mm×120mm sample from the free membrane and immerse it in deionized water at (23±2)℃ for 168h. After removal, use filter paper to absorb the surface water and place it at room temperature for 1h. Visually observe it. Record "no blistering, no peeling, no cracking" if there is no blistering, no peeling, and no cracking. Record any defects as they occur.

[0058] Total fluorine content: Oxygen bomb combustion-ion chromatography was performed according to the method specified in this instruction manual. The cured coating was pulverized and passed through a 60-mesh sieve. 0.20 g of the sample was placed in an oxygen bomb, and 10.0 mL of a 10 mmol / L sodium hydroxide absorbent solution was added. Combustion was carried out under 3.0 MPa oxygen conditions. After combustion, the inner wall of the oxygen bomb was washed with an appropriate amount of ultrapure water, and the volume was adjusted to 50.0 mL. The concentration (c) of fluoride ions in the solution was determined using ion chromatography. A series of standard solutions (0.05 mg / L, 0.10 mg / L, 0.50 mg / L, 1.00 mg / L, and 2.00 mg / L) were prepared using fluoride ion standard solutions to establish a working curve. The linear correlation coefficient (R²) was not less than 0.999. The chromatographic conditions were: IonPac AS19 analytical column (250 mm × 4 mm) and AG19 guard column (50 mm × 4 mm); eluent was 30 mmol / L KOH; flow rate was 1.0 mL / min; column temperature was 30 °C; and inhibited conductivity detection was used. The total fluoride content was calculated as c × V / m, where c is in mg / L, V is in L, and m is in kg. The result unit was mg / kg. The method detection limit was 5.0 mg / kg. Results below the detection limit were recorded as <5.0 mg / kg.

[0059] Particle morphology retention at 80℃: The 80℃ heat treatment-microscopic counting method was used. 0.50 g each of the bio-based hydrophobic multi-peak crystalline particles or their additives used in each example and comparative example were spread evenly in 60 mm diameter glass dishes and placed in an 80℃ forced-air oven for 2 hours. After cooling to room temperature, the coarse and fine particle groups were observed separately. For the coarse particle group, 10 fields of view were randomly photographed at 200x using a digital microscope, with at least 100 particles counted in each field. For the fine particle group, the samples were fixed to an aluminum sample stage with conductive carbon adhesive, without metal sputtering. Field emission scanning electron microscopes (FESEM) as listed in Table 2 were used for observation in low vacuum mode, with an accelerating voltage of 5.0 kV, a working distance of 8 mm to 10 mm, and a magnification of 10000x. 10 fields of view were randomly photographed, with at least 200 particles counted in each field. The particles had intact edges, no mutual fusion, and compared to the untreated control sample of the same batch, their equivalent circle diameter (ECD) was 2 × (S / π). 0.5 Particles with an average variation of no more than 15% were considered to have complete outlines, where S is the projected area of ​​a single particle, measured after thresholding the microscopic image using ImageJ software. The morphology retention rate was calculated as "(number of coarse particles with complete outlines + number of fine particles with complete outlines) / (total number of coarse particles + total number of fine particles) × 100%", with each sample tested three times and the arithmetic mean taken.

[0060] Stain resistance rating and dust collection at 80℃: The 80℃ heat treatment-artificial contamination dust collection method was used. The cured fiber cement board sample was placed in an 80℃ forced-air oven for 30 minutes, then removed and 0.50g of simulated contaminant powder was evenly spread over a 100mm×50mm test area. The simulated contaminant powder was prepared by mixing carbon black N330, 325-mesh talc powder, and 500-mesh quartz powder in a mass ratio of 1:1:1. After standing for 10 minutes, it was placed on a horizontal vibration table and vibrated horizontally at a frequency of 100 times / min and an amplitude of 5mm for 30 seconds. The sample was then inverted to remove any unattached powder. The sample mass m1 before powder application and the sample mass m2 after removing the unattached powder were recorded. The dust collection amount was calculated as (m2-m1) / A, where A is 0.0050m². The sample surface was then rinsed twice with 250 mL of deionized water within 15 seconds, and allowed to air dry for 2 hours. The SRI after rinsing was then measured according to the methods described above for "Solar Reflectance, Hemispherical Emissivity, SRI, SRI after Rinsing, and SRI Retention Rate after 2000 hours of Xenon Arc Aging". The contamination resistance level was evaluated according to the following standards: A 100 mm × 50 mm test area was covered with a 5 mm × 5 mm transparent grid film, for a total of 200 grids. Under a D65 light source, when the visible contamination film coverage area in a single grid reached or exceeded 50% of the grid area, it was recorded as one contaminated grid; adjacent contaminated grids sharing the same edge were considered continuous contaminated grids, while grids with only corner contact were not considered continuous; the number of grids covered by the largest continuous contamination area was taken as the number of grids covered by the continuous contamination film. Grade 1 is defined as dust accumulation ≤ 1.20 g / m² and continuous fouling membrane coverage < 10 cells; Grade 2 is defined as dust accumulation > 1.20 g / m² and ≤ 2.00 g / m², or continuous fouling membrane coverage between 10 and 30 cells; Grade 3 is defined as dust accumulation > 2.00 g / m², or continuous fouling membrane coverage > 30 cells. Each sample is tested three times. The dust accumulation at 80℃ is taken as the arithmetic mean of the three tests, and the fouling resistance grade is taken as the mode of the three results. If there is no unique mode, the higher grade is taken as the final result.

[0061] UVA retention rate on particle surface: The ethanol extraction-UV spectrophotometric method was used. 0.50 g of the bio-based hydrophobic multi-peak crystalline particle additive or particle sample used in each example and comparative example was weighed and added to 50.0 mL of anhydrous ethanol. The mixture was magnetically stirred at 300 r / min for 30 min at 25 °C. Then, it was centrifuged at 6080 × g for 10 min. The supernatant was filtered through a 0.22 μm polytetrafluoroethylene filter membrane, and the absorbance was measured at 343 nm using a UV-Vis-NIR spectrophotometer. A series of standard solutions with concentrations of 0.5 mg / L, 1.0 mg / L, 2.0 mg / L, 4.0 mg / L, 6.0 mg / L, and 8.0 mg / L were prepared using Tinuvin 328 ethanol standard solution, and their absorbance was measured at 343 nm. Linear regression was performed on the absorbance against the mass concentration, and the correlation coefficient R² was not less than 0.999. After correction with anhydrous ethanol as a blank, the UVA content in the filtrate was calculated. The UVA surface retention rate is calculated as "(initial UVA addition amount - UVA extraction amount) / initial UVA addition amount × 100%", where the initial UVA addition amount is calculated as m0 × η × (1-p) × b / [(1+ω h Calculate ω = (a+b)×(a+b)], where m0 is the mass of the test sample, and ω is the mass of the test sample. h The amount of hydrophobic modifier is the percentage of the dry-based particle mass, expressed as a decimal; when using stearic acid for hydrophobic modification in this specification, ω h Take 0.020; when using other fatty acids or fatty acid salts for hydrophobic modification, ω h The value is taken as the ratio of the actual amount of hydrophobic modifier added to the mass of dry-based particles; η is the amount of weather-resistant protective layer used, expressed as a decimal; p is the mass fraction of inorganic ultraviolet shielding agent, expressed as a decimal; a:b is the mass ratio of HALS:UVA; p is 0 in Comparative Example 8, and this item is marked as "-" in Comparative Example 9.

[0062] Verification of the dispersed phase and surface weathering resistance of the coating: Fiber cement board samples cured for 7 days and equilibrated for 24 hours were immersed in liquid nitrogen for 5 minutes until brittle fracture occurred. The fracture surface was fixed on an aluminum sample stage and sputtered with gold for 60 seconds. The coating cross-section was observed using a field emission scanning electron microscope (FET) as listed in Table 2, with an observation voltage of 5.0 kV, a working distance of 8 mm to 10 mm, and a magnification of 3000x. Five cross-sectional fields of view were randomly selected for each sample, each with an area of ​​100 μm × 75 μm. ImageJ software was used to perform threshold segmentation on regions with particle protrusions, boundary differences with the continuous emulsion film-forming matrix, and corresponding elemental surface scans showing Zn enrichment signals or PHA particle morphology characteristics. The projected area of ​​all PHA particle phases and the projected area of ​​the single largest continuous PHA particle phase were statistically analyzed. The percentage of the largest continuous PHA phase area was calculated as "projected area of ​​the single largest continuous PHA particle phase / projected area of ​​all PHA particle phases × 100%". When the area ratio of the largest continuous PHA phase is less than 15.0%, and no continuous PHA phase with a width of more than 50% through the field of view is observed in any of the five cross-sectional fields of view, it is judged as "particulate dispersion phase that does not form a continuous film"; when the area ratio of the largest continuous PHA phase is between 15.0% and 20.0%, or when a continuous PHA phase with a width of more than 50% through the field of view appears in one of the five cross-sectional fields of view, it is judged as "locally bridged particulate phase"; when the area ratio of the largest continuous PHA phase is greater than 20.0%, or when a continuous PHA phase with a width of more than 50% through the field of view appears in two or more of the five cross-sectional fields of view, it is judged as "forming a locally continuous particulate phase".

[0063] Simultaneously, a scanning electron microscope paired with an energy dispersive spectroscopy (EDS) was used to perform surface scanning of Zn elements on the particle surface, with an accelerating voltage of 10.0 kV and a acquisition time of 60 s. Zn element surface coverage was calculated as "Zn element signal coverage area of ​​particle outer contour / particle projected area × 100%", with at least 30 particles counted for each sample and their arithmetic mean taken. For samples without nano-zinc oxide surface weathering loading treatment, if Zn elements were only distributed as free point particles in the emulsion matrix and did not cover the outer contour of the PHA particles, the surface coverage was calculated based on the effective Zn signal area within the particle outer contour region.

[0064] 100-mesh sieve residue, number of surface defects, and 80℃ softening and leveling grade: Take 200g of each of the coating samples from the examples and comparative examples, filter them through a 100-mesh nylon filter at 25℃, collect the residue on the filter screen, dry it at 60℃ for 30min, and weigh it. Record this as the 100-mesh sieve residue. Prepare the filtered samples into films according to the aforementioned film preparation method and cure them for 7 days. Count the number of pinholes, shrinkage cavities, and obvious particle accumulation defects with a diameter greater than 0.2mm in the effective area of ​​a 150mm×75mm sample, n, and convert it to the number of surface defects per 100cm² using "n / 112.5×100". Then place the sample in an 80℃ forced-air oven for 2h, cool it to room temperature, and observe it visually under a D65 light source. Verify the continuous bright flow marks on the surface using a digital microscope at 50x magnification. A 5mm × 5mm transparent grid film is used to cover the effective area of ​​a 150mm × 75mm sample, totaling 450 grids. The number of grids with continuous glossy flow marks is recorded as N, and the leveling area percentage is calculated as N / 450 × 100%. Level 0 is defined as no continuous glossy flow marks and surface particle protrusions remaining largely intact; Level 1 is defined as localized continuous glossy flow marks with a leveling area percentage not exceeding 10%; and Level 2 is defined as obvious continuous glossy flow marks with a leveling area percentage exceeding 10%.

[0065] Fineness of reflective paste: Tested according to GB / T1724-2019 "Determination of grinding fineness of paints, varnishes and printing inks". Unless otherwise specified, the experimental environment was 23±2℃ and 50±5% relative humidity.

[0066] Organosilicon-modified acrylic emulsion can be prepared as follows: 18.0 parts of deionized water, 0.45 parts of sodium dodecyl sulfate, and 0.45 parts of octylphenol polyoxyethylene ether OP-10 are added to a reactor equipped with a mechanical stirrer, thermometer, dropping device, and reflux condenser. The mixture is stirred at 300 r / min for 15 min until completely dissolved. 34.0 parts of butyl acrylate, 12.0 parts of methyl methacrylate, 3.0 parts of styrene, 1.0 part of acrylic acid, and 0.8 parts of 3-methacryloyloxypropyltrimethoxysilane are mixed, and then 24.8 parts of deionized water and the balance 0.60 parts of octylphenol polyoxyethylene ether OP-10 are added. The mixture is pre-emulsified at 4000 r / min for 45 min to obtain a stable monomer pre-emulsion. Separately, 0.35 parts of ammonium persulfate and 0.15 parts of sodium bisulfite are dissolved in 5.0 parts of deionized water to prepare initiator aqueous solutions. The reaction system was heated to 78℃, and 10% of the total pre-emulsion mass, along with 20% each of ammonium persulfate solution and sodium bisulfite solution, were added for seed polymerization for 30 min. Subsequently, the remaining monomer pre-emulsion and the remaining initiator aqueous solution were added dropwise over 3 h, with continuous stirring maintained during the dropwise addition and the reaction temperature controlled at 78±2℃ and the stirring speed at 300 r / min. After the dropwise addition was completed, the system was kept at the same temperature for 1.5 h to reduce the residual monomer content. Then, the system was cooled to below 40℃, and the pH was adjusted to 7.5±0.2 with approximately 0.4 parts of 10% ammonia water. The gel was removed by filtration, and if necessary, a small amount of deionized water was used for fine-tuning to make the emulsion solid content 50.0%±0.5%, thus obtaining the DBC-SA50 organosilicon-modified acrylic emulsion.

[0067] Preparation of bio-based hydrophobic multimodal crystalline particles and their additives

[0068] Preparation of coarse PHB particles

[0069] Step 1: Completely immerse PB3000G type PHB resin particles in liquid nitrogen for pre-cooling for 10 minutes, then transfer them to a JXFSTPRP-CLN cryogenic pulverizer for pulverization. The pulverization speed is 18000 r / min, and the pulverization method is pulverization for 30 seconds, followed by intermittent replenishment of liquid nitrogen for 60 seconds, for a total of 5 cycles. After pulverization, the particles are sieved through an 80-mesh sieve to obtain PHB coarse powder.

[0070] Step 2: The PHB coarse powder is fed into an air classifier, the classifier wheel speed is set to 4500 r / min, the feed rate is set to 1.8 kg / h, and the PHB coarse particle fraction with a volume weighted average particle size of 12.6 μm is collected.

[0071] Step 3: Place the PHB crude particle fraction obtained in Step 2 in a vacuum drying oven at 60℃ and dry for 4 hours.

[0072] Step 4: Use a laser particle size analyzer to retest the coarse PHB particles obtained in Step 3. Once they pass the test, they can be used for future reference.

[0073] Preparation of PHBV fine particles

[0074] Step 1: Immerse PV3000G type PHBV resin completely in liquid nitrogen for pre-cooling for 10 minutes, then transfer it to a JXFSTPRP-CLN cryogenic pulverizer for pulverization. The pulverization speed is 18000 r / min, and the pulverization method is pulverization for 30 seconds, followed by intermittent replenishment of liquid nitrogen for 60 seconds, for a total of 5 cycles. After pulverization, the resin is sieved through an 80-mesh sieve to obtain PHBV pre-powder.

[0075] Step 2: Weigh polyvinyl alcohol and add it to deionized water. Stir and dissolve at 90°C for 1 hour. After cooling to 25°C, prepare a 1.0% polyvinyl alcohol aqueous solution.

[0076] Step 3: Add the PHBV pre-powder to the polyvinyl alcohol aqueous solution obtained in Step 2 at a mass fraction of 6.0% in the dispersion system, and pre-disperse it at 1500 r / min for 15 min at 25℃ to obtain PHBV aqueous phase coarse dispersion slurry.

[0077] Step 4: The PHBV aqueous coarse dispersion slurry obtained in Step 3 is subjected to aqueous high-pressure homogenization and refinement. The homogenization pressure is 80 MPa, and the homogenization is repeated 4 times to obtain the PHBV aqueous fine dispersion slurry.

[0078] Step 5: Centrifuge the PHBV aqueous fine dispersion slurry obtained in Step 4 at 850×g for 5 min to remove large particles that have not been refined. Then take the supernatant and centrifuge at 6080×g for 10 min. Collect the precipitated particles, resuspend and wash twice with deionized water, and then freeze-dry for 24 h.

[0079] Step 6: The obtained PHBV fine particles were re-measured using a laser particle size analyzer to obtain PHBV fine particles with a volume-weighted average particle size of 0.33 μm.

[0080] Preparation of P34HB fine particles

[0081] Step 1: Immerse PHACT™ S1000P type P34HB resin completely in liquid nitrogen for pre-cooling for 10 minutes, then transfer it to a JXFSTPRP-CLN cryogenic pulverizer for pulverization. The pulverization speed is 18000 r / min, and the pulverization method is pulverization for 30 seconds, followed by intermittent replenishment of liquid nitrogen for 60 seconds, for a total of 5 cycles. After pulverization, the resin is sieved through an 80-mesh sieve to obtain P34HB pre-powder.

[0082] Step 2: Weigh polyvinyl alcohol and add it to deionized water. Stir and dissolve at 90°C for 1 hour. After cooling to 25°C, prepare a 1.0% polyvinyl alcohol aqueous solution.

[0083] Step 3: Add the P34HB pre-powder to the polyvinyl alcohol aqueous solution obtained in Step 2 at a mass fraction of 5.0% in the dispersion system, and pre-disperse it at 1600 r / min for 15 min at 25℃ to obtain P34HB aqueous phase coarse dispersion slurry.

[0084] Step 4: The P34HB aqueous coarse dispersion slurry obtained in Step 3 is subjected to aqueous high-pressure homogenization and refinement. The homogenization pressure is 85MPa, and the homogenization is repeated 4 times to obtain the P34HB aqueous fine dispersion slurry.

[0085] Step 5: Centrifuge the P34HB aqueous fine dispersion slurry obtained in Step 4 at 850×g for 5 min to remove large particles that have not been refined. Then take the supernatant and centrifuge at 6080×g for 10 min. Collect the precipitated particles, resuspend and wash twice with deionized water, and then freeze-dry for 24 h.

[0086] Step 6: The obtained P34HB fine particles were re-measured using a laser particle size analyzer, and P34HB fine particles with a volume-weighted average particle size of 0.41 μm were obtained.

[0087] Specific preparation and sample definition for each embodiment and comparative example

[0088] In each embodiment and comparative example, bio-based hydrophobic multimodal crystalline particles or their additives, as well as finished coating samples, were prepared. Unless otherwise stated, the coarse particle fraction was PHB coarse particles, and the fine particle fraction was PHBV fine particles or P34HB fine particles; the annealing conditions in each embodiment and comparative example were based on the specific values ​​specified in the corresponding embodiment and comparative example; samples not otherwise specified were annealed according to the conditions of Example 1, i.e., the coarse particle fraction was annealed at 80°C for 4 hours, and the fine particle fraction was annealed at 55°C for 2 hours. Unless otherwise stated, the reflective components are all composed of rutile titanium dioxide and near-infrared reflective black composite metal oxide pigment in a mass ratio of 18:4; the heat-insulating filler is all hollow glass microspheres; the functional additive mixture is composed of 34.29% dispersant, 8.57% wetting agent, 5.71% defoamer, 5.71% leveling agent, 22.86% thickener, 5.71% preservative, and 17.14% film-forming aid, all of which are mass percentages of each component within the functional additive mixture; deionized water is used as the dispersion medium. Except for Comparative Example 9, the bio-based hydrophobic multi-peak crystalline particles in each example and the other comparative examples were first hydrophobized with fatty acids or fatty acid salts and then surface-treated with HALS / UVA / nano zinc oxide to prepare solid powder additives before being added to the coating system. The particles exist as a particulate dispersion phase that does not form a continuous film in the resulting coating film. The finished coating samples in each example and comparative example were prepared according to their respective mass proportions and process conditions.

[0089] Example 1

[0090] Bio-based hydrophobic multi-peak crystalline particle additive samples:

[0091] PHB coarse particles were prepared according to steps 1 to 4 of the aforementioned "Preparation of PHB Coarse Particles". In step 2, the classifier wheel speed was 4500 r / min and the feed rate was 1.8 kg / h, resulting in PHB coarse particles with a volume-weighted average particle size of 12.6 μm. After the particle size was verified to be acceptable, the particles were annealed at 80°C for 4 h and then cooled to 23°C in the furnace. PHBV fine particles were prepared according to steps 1 to 6 of the aforementioned "Preparation of PHBV Fine Particles". In step 3, the solid content of the PHBV aqueous phase coarse dispersion slurry was 6.0%. In step 4, the homogenization pressure was 80 MPa and the homogenization was performed 4 times, resulting in PHBV fine particles with a volume-weighted average particle size of 0.33 μm. After the particle size was verified to be acceptable, the particles were annealed at 55°C for 2 h and then placed at 23°C for 24 h. The coarse PHB particles and fine PHBV particles were mixed at a mass ratio of 75:25. The resulting multi-peak particles had a coarse particle group volume-weighted average particle size of 12.6 μm and a fine particle group volume-weighted average particle size of 0.33 μm. The mass ratio of the coarse particle group to the fine particle group was 75:25. 10 It is 0.12μm, D 50 It is 8.5μm, D 90 The particle size distribution was 30.2 μm, peak position 1 was 0.33 μm, peak position 2 was 9.8 μm, crystallinity was 56%, and the main melting peak temperature was 168.4 °C. Stearic acid was then added at 2.0% of the total particle mass, and the mixture was stirred at 65 °C and 600 r / min for 10 min to obtain hydrophobically modified multi-peak crystalline particles. Then, HALS, UVA, and nano-zinc oxide were added at 1.5% of the dry weight of the particles for the weather-resistant protective layer, with a HALS to UVA mass ratio of 1:1 and nano-zinc oxide accounting for 30% of the total mass of the weather-resistant protective layer. The mixture was first dry-mixed at 500 r / min for 5 min, and then dry-pretreated at 60 °C for 12 min to allow HALS, UVA, and nano-zinc oxide to adhere to the particle surface, forming a weather-resistant protective layer, thus obtaining the bio-based hydrophobic multi-peak crystalline particle additive sample of Example 1.

[0092] Finished coating sample: By weight, weigh 39.5 parts of silicone-modified acrylic emulsion (based on solid content), 22 parts of reflective component, 6 parts of heat-insulating filler, 8 parts of bio-based hydrophobic multi-peaked crystalline particles (using the bio-based hydrophobic multi-peaked crystalline particle additive sample from Example 1), 3.5 parts of functional additives, including 1.20 parts of dispersant, 0.30 parts of wetting agent, 0.20 parts of defoamer, 0.20 parts of leveling agent, 0.80 parts of thickener, 0.20 parts of preservative, and 0.60 parts of film-forming aid, and 21 parts of water; the mass ratio of the bio-based hydrophobic multi-peaked crystalline particles to the aqueous film-forming base material is 0.203 by solid content. In preparation, water, dispersant, and reflective components were first added to a dispersion tank and sheared at 2200 r / min for 18 min, controlling the slurry temperature to be no higher than 35℃ and the fineness of the reflective slurry to be controlled to 32 μm; then, water-based film-forming base material was added and stirred at 450 r / min for 10 min; subsequently, heat-insulating filler was added and stirred at 250 r / min for 8 min; then, the above-mentioned bio-based hydrophobic multi-peak crystalline particle additive was added and dispersed at 300 r / min for 20 min, with the maximum material temperature controlled at 50℃; finally, wetting agent, defoamer, leveling agent, thickener, preservative, and film-forming aid were added, stirred for 12 min, filtered through a 100-mesh filter, and packaged to obtain the finished coating sample of Example 1.

[0093] Example 2:

[0094] The preparation of the bio-based hydrophobic multi-peak crystalline particle additive sample was the same as in Example 1, except that: in the preparation of PHB coarse particles, the classifier wheel speed in step 2 was 4800 r / min, and the feed rate was 1.6 kg / h, resulting in PHB coarse particles with a volume-weighted average particle size of 11.4 μm. After the particle size was verified to be qualified, the particles were annealed at 80°C for 2 h and then cooled to 23°C in the furnace. In the preparation of PHBV fine particles, the PHBV aqueous phase coarse dispersion slurry in step 3 was... The solid content was 6.0%. In step 4, the homogenization pressure was 90 MPa, and homogenization was performed 5 times to obtain PHBV fine particles with a volume-weighted average particle size of 0.28 μm. After passing particle size retesting, the particles were annealed at 55℃ for 1 hour and then placed at 23℃ for 24 hours. The obtained multi-peaked particles had a coarse particle group volume-weighted average particle size of 11.4 μm and a fine particle group volume-weighted average particle size of 0.28 μm. The mass ratio of coarse to fine particles was 70:30. 10 For 0.10 μm, D 50 It is 6.8μm, D 90The peak size was 25.6 μm, peak position 1 was 0.28 μm, peak position 2 was 8.4 μm, crystallinity was 45%, and the main melting peak temperature was 161.2 °C. The hydrophobic modification steps were the same as in Example 1. In the weathering treatment conditions, the amount of weathering protective layer was 0.8% based on the dry mass of the particles, the mass ratio of HALS to UVA was 0.5:1, and nano zinc oxide accounted for 20% of the total mass of the weathering protective layer, thus obtaining the bio-based hydrophobic multi-peak crystalline particle additive sample of Example 2.

[0095] Finished coating sample: By weight, 42 parts of silicone-modified acrylic emulsion, 25 parts of reflective component, 10 parts of heat-insulating filler, 3 parts of bio-based hydrophobic multimodal crystalline particles (using the bio-based hydrophobic multimodal crystalline particle additive sample from Example 2), and 3.0 parts of functional additives, including 1.0286 parts of dispersant, 0.2571 parts of wetting agent, 0.1714 parts of defoamer, 0.1714 parts of leveling agent, 0.6857 parts of thickener, 0.1714 parts of preservative, and 0.5143 parts of film-forming aid, and 18 parts of water; the mass ratio of the bio-based hydrophobic multimodal crystalline particles to the aqueous film-forming base material, based on solid content, is 0.071. The preparation steps of the finished coating sample are the same as those of the finished coating sample in Example 1.

[0096] Example 3:

[0097] The preparation of the bio-based hydrophobic multi-peak crystalline particle additive sample was the same as in Example 1, except that: in the preparation of PHB coarse particles, the classifier wheel speed in step 2 was 4200 r / min, and the feed rate was 1.9 kg / h, resulting in PHB coarse particles with a volume-weighted average particle size of 13.8 μm. After the particle size was verified to be qualified, the particles were annealed at 80°C for 4 h and then cooled to 23°C in the furnace. The fine particles were replaced with P34HB fine particles prepared according to steps 1 to 6 of the aforementioned "Preparation of P34HB Fine Particles". In step 3, the solid content of the P34HB aqueous phase coarse dispersion slurry was 5.0%. In step 4, the homogenization pressure was 85 MPa, and the homogenization was performed four times to obtain P34HB fine particles with a volume-weighted average particle size of 0.41 μm. After the particle size was verified to be qualified, the particles were annealed at 55℃ for 2 hours and then placed at 23℃ for 24 hours. The obtained multi-peaked particles had a coarse particle group volume-weighted average particle size of 13.8 μm and a fine particle group volume-weighted average particle size of 0.41 μm. The mass ratio of coarse to fine particles was 80:20. 10 It is 0.18μm, D 50 It is 9.2 μm, D 90The peak size was 32.0 μm, peak position 1 was 0.41 μm, peak position 2 was 10.5 μm, crystallinity was 58%, and the main melting peak temperature was 169.1 °C. The hydrophobic modification steps were the same as in Example 1. In the weathering treatment conditions, the amount of weathering protective layer was 1.8% based on the dry weight of the particles, the mass ratio of HALS to UVA was 6:5, and nano zinc oxide accounted for 40% of the total mass of the weathering protective layer, thus obtaining the bio-based hydrophobic multi-peak crystalline particle additive sample of Example 3.

[0098] Finished coating sample: By weight, 45 parts of silicone-modified acrylic emulsion, 20 parts of reflective component, 5 parts of heat-insulating filler, 12 parts of bio-based hydrophobic multimodal crystalline particles (using the bio-based hydrophobic multimodal crystalline particle additive sample from Example 3), 4.0 parts of functional additives, including 1.3714 parts of dispersant, 0.3429 parts of wetting agent, 0.2286 parts of defoamer, 0.2286 parts of leveling agent, 0.9143 parts of thickener, 0.2286 parts of preservative, and 0.6857 parts of film-forming aid, and 16 parts of water; the mass ratio of the bio-based hydrophobic multimodal crystalline particles to the aqueous film-forming base material, based on solid content, is 0.267. The preparation steps of the finished coating sample are the same as those of the finished coating sample in Example 1.

[0099] Example 4:

[0100] The preparation of the bio-based hydrophobic multi-peak crystalline particle additive sample was the same as in Example 1, except that: in the preparation of PHB coarse particles, the classifier wheel speed in step 2 was 3900 r / min, and the feed rate was 2.0 kg / h, resulting in PHB coarse particles with a volume-weighted average particle size of 15.2 μm. After the particle size was verified to be qualified, the particles were annealed at 80°C for 6 h and then cooled to 23°C in the furnace. The fine particles were replaced with P34HB fine particles prepared according to steps 1 to 6 of the aforementioned "Preparation of P34HB Fine Particles". In step 3, the solid content of the P34HB aqueous coarse dispersion slurry was 5.0%. In step 4, the homogenization pressure was 70 MPa, and homogenization was performed three times to obtain P34HB fine particles with a volume-weighted average particle size of 0.48 μm. After the particle size was verified to be qualified, the particles were annealed at 65℃ for 3 h and then placed at 23℃ for 24 h. The obtained multi-peaked particles had a coarse particle group volume-weighted average particle size of 15.2 μm and a fine particle group volume-weighted average particle size of 0.48 μm. The mass ratio of coarse to fine particles was 65:35. 10 It is 0.24μm, D 50 It is 9.8 μm, D 90The peak size was 34.5 μm, peak position 1 was 0.48 μm, peak position 2 was 12.2 μm, crystallinity was 65%, and the main melting peak temperature was 172.8 °C. The hydrophobic modification steps were the same as in Example 1. In the weathering treatment conditions, the amount of weathering protective layer was 2.5% based on the dry weight of the particles, the mass ratio of HALS to UVA was 4:3, and nano zinc oxide accounted for 50% of the total mass of the weathering protective layer, thus obtaining the bio-based hydrophobic multi-peak crystalline particle additive sample of Example 4.

[0101] Finished coating sample: By weight, 35 parts of silicone-modified acrylic emulsion, 30 parts of reflective component, 15 parts of heat-insulating filler, 20 parts of bio-based hydrophobic multimodal crystalline particles (using the bio-based hydrophobic multimodal crystalline particle additive sample from Example 4), 5.0 parts of functional additives, including 1.7143 parts of dispersant, 0.4286 parts of wetting agent, 0.2857 parts of defoamer, 0.2857 parts of leveling agent, 1.1429 parts of thickener, 0.2857 parts of preservative, and 0.8571 parts of film-forming aid, and 12 parts of water; the mass ratio of the bio-based hydrophobic multimodal crystalline particles to the aqueous film-forming base material, based on solid content, is 0.571. The preparation steps of the finished coating sample are the same as those of the finished coating sample in Example 1.

[0102] Example 5:

[0103] The preparation of the bio-based hydrophobic multi-peak crystalline particle additive sample was the same as in Example 1, except that: in the preparation of PHB coarse particles, the classifier wheel speed in step 2 was 3600 r / min, and the feed rate was 2.2 kg / h, resulting in PHB coarse particles with a volume-weighted average particle size of 16.8 μm. After the particle size was verified to be qualified, the particles were annealed at 80°C for 1 h and then cooled to 23°C in the furnace. In the preparation of PHBV fine particles, the PHBV aqueous phase coarse dispersion slurry in step 3 was... The solid content was 6.0%. In step 4, the homogenization pressure was 65 MPa, and homogenization was performed three times to obtain PHBV fine particles with a volume-weighted average particle size of 0.50 μm. After passing particle size retesting, the particles were annealed at 55℃ for 0.5 h and then placed at 23℃ for 24 h. The obtained multi-peaked particles had a coarse particle group volume-weighted average particle size of 16.8 μm and a fine particle group volume-weighted average particle size of 0.50 μm. The mass ratio of coarse to fine particles was 85:15. 10 It is 0.25μm, D 50 It is 10.0 μm, D 90 The peak size was 35.0 μm, peak position 1 was 0.50 μm, peak position 2 was 13.0 μm, crystallinity was 40%, and the main melting peak temperature was 150.6 °C. The hydrophobic modification steps were the same as in Example 1. In the weathering treatment conditions, the amount of weathering protective layer was 1.2% based on the dry weight of the particles, the mass ratio of HALS to UVA was 1:2, and nano zinc oxide accounted for 10% of the total mass of the weathering protective layer, thus obtaining the bio-based hydrophobic multi-peak crystalline particle additive sample of Example 5.

[0104] Finished coating sample: By weight, weigh 50 parts of silicone-modified acrylic emulsion, 15 parts of reflective component, 1 part of heat-insulating filler, 5 parts of bio-based hydrophobic multimodal crystalline particles (using the bio-based hydrophobic multimodal crystalline particle additive sample from Example 5), 4.0 parts of functional additives, including 1.3714 parts of dispersant, 0.3429 parts of wetting agent, 0.2286 parts of defoamer, 0.2286 parts of leveling agent, 0.9143 parts of thickener, 0.2286 parts of preservative, and 0.6857 parts of film-forming aid, and 20 parts of water; the mass ratio of the bio-based hydrophobic multimodal crystalline particles to the aqueous film-forming base material, based on solid content, is 0.100. The preparation steps of the finished coating sample are the same as those of the finished coating sample in Example 1.

[0105] Example 6

[0106] The preparation of the bio-based hydrophobic multi-peak crystalline particle additive sample was the same as in Example 1, except that: in the preparation of PHB coarse particles, the classifier wheel speed in step 2 was 5200 r / min, and the feed rate was 1.5 kg / h, resulting in PHB coarse particles with a volume-weighted average particle size of 10.0 μm. After the particle size was verified to be qualified, the particles were annealed at 80℃ for 2 h and then cooled to 23℃ in the furnace. In the preparation of PHBV fine particles, the PHBV aqueous phase coarse dispersion slurry in step 3 was... The solid content was 6.0%. In step 4, the homogenization pressure was 85 MPa, and homogenization was performed four times to obtain PHBV fine particles with a volume-weighted average particle size of 0.30 μm. After passing particle size retesting, the particles were annealed at 55℃ for 0.5 h and then placed at 23℃ for 24 h. The obtained multi-peaked particles had a coarse particle group volume-weighted average particle size of 10.0 μm and a fine particle group volume-weighted average particle size of 0.30 μm. The mass ratio of coarse to fine particles was 70:30. 10 It is 0.11μm, D 50 It is 6.5μm, D 90 The peak size was 27.0 μm, peak position 1 was 0.30 μm, peak position 2 was 8.6 μm, crystallinity was 44%, and the main melting peak temperature was 155.4 °C. The hydrophobic modification steps were the same as in Example 1. In the weathering treatment conditions, the amount of weathering protective layer was 1.0% based on the dry weight of the particles, the mass ratio of HALS to UVA was 1:1, the nano zinc oxide accounted for 25% of the total mass of the weathering protective layer, the dry pretreatment temperature was 40 °C, and the dry pretreatment time was 3 min, thus obtaining the bio-based hydrophobic multi-peak crystalline particle additive sample of Example 6.

[0107] Finished coating sample: By weight, weigh 20 parts of silicone-modified acrylic emulsion, 5 parts of reflective component, 0.5 parts of heat-insulating filler, 3 parts of bio-based hydrophobic multi-peaked crystalline particles (using the bio-based hydrophobic multi-peaked crystalline particle additive sample from Example 6), 0.1 parts of functional additives, including 0.0343 parts of dispersant, 0.0086 parts of wetting agent, 0.0057 parts of defoamer, 0.0057 parts of leveling agent, 0.0229 parts of thickener, 0.0057 parts of preservative, and 0.0171 parts of film-forming aid, and 45 parts of water; the mass ratio of the bio-based hydrophobic multi-peaked crystalline particles to the aqueous film-forming base material, based on solid content, is 0.150. During preparation, in step 1, the material was sheared and dispersed at 1200 r / min for 5 min; in step 2, it was stirred at 200 r / min for 5 min; in step 3, it was stirred at 100 r / min for 5 min; in step 4, it was dispersed at 150 r / min for 10 min, and the maximum material temperature was controlled at 50℃; in step 5, it was stirred for 10 min and then filtered and packaged; the rest was consistent with the finished coating sample of Example 1.

[0108] Example 7:

[0109] The preparation of the bio-based hydrophobic multi-peak crystalline particle additive sample was the same as in Example 1, except that: in the preparation of PHB coarse particles, the classifier wheel speed in step 2 was 3300 r / min, and the feed rate was 2.3 kg / h, resulting in PHB coarse particles with a volume-weighted average particle size of 18.5 μm. After the particle size was verified to be qualified, the particles were annealed at 80°C for 6 h and then cooled to 23°C in the furnace. The fine particles were prepared according to steps 1 to 6 of the aforementioned "Preparation of P34HB Fine Particles" as P34HB fine particles. In step 3, the solid content of the P34HB aqueous coarse dispersion slurry was 5.0%. In step 4, the homogenization pressure was 75 MPa, and the homogenization was performed four times to obtain P34HB fine particles with a volume-weighted average particle size of 0.45 μm. After the particle size was verified to be qualified, the particles were annealed at 55℃ for 3 hours and then placed at 23℃ for 24 hours. The obtained multi-peaked particles had a coarse particle group volume-weighted average particle size of 18.5 μm and a fine particle group volume-weighted average particle size of 0.45 μm. The mass ratio of coarse to fine particles was 72:28. 10 It is 0.16μm, D 50 It is 9.6 μm, D 90 The peak size was 33.8 μm, peak position 1 was 0.45 μm, peak position 2 was 12.8 μm, crystallinity was 62%, and the main melting peak temperature was 171.5 °C. The hydrophobic modification steps were the same as in Example 1. In the weathering treatment conditions, the amount of weathering protective layer was 2.2% based on the dry weight of the particles, the mass ratio of HALS to UVA was 8:6, the nano zinc oxide accounted for 60% of the total mass of the weathering protective layer, the dry pretreatment temperature was 80 °C, and the dry pretreatment time was 20 min, thus obtaining the bio-based hydrophobic multi-peak crystalline particle additive sample of Example 7.

[0110] Finished coating sample: By weight, weigh 75 parts of silicone-modified acrylic emulsion, 45 parts of reflective component, 30 parts of heat-insulating filler, 20 parts of bio-based hydrophobic multi-peaked crystalline particles (using the bio-based hydrophobic multi-peaked crystalline particle additive sample from Example 7), 12 parts of functional additives, including 4.1143 parts of dispersant, 1.0286 parts of wetting agent, 0.6857 parts of defoamer, 0.6857 parts of leveling agent, 2.7429 parts of thickener, 0.6857 parts of preservative, and 2.0571 parts of film-forming aid, and 5 parts of water; the mass ratio of the bio-based hydrophobic multi-peaked crystalline particles to the aqueous film-forming base material, based on solid content, is 0.267. During preparation, in step 1, the material was sheared and dispersed at 3000 r / min for 30 min; in step 2, it was stirred at 800 r / min for 15 min; in step 3, it was stirred at 400 r / min for 15 min; in step 4, it was dispersed at 600 r / min for 40 min, and the maximum material temperature was controlled at 50℃; in step 5, it was stirred for 20 min and then filtered and packaged; the rest was consistent with the finished coating sample of Example 1.

[0111] Example 8:

[0112] The preparation of the bio-based hydrophobic multi-peak crystalline particle additive sample was the same as in Example 1, except that: in the preparation of PHB coarse particles, the classifier wheel speed in step 2 was 5800 r / min, and the feed rate was 1.2 kg / h, resulting in PHB coarse particles with a volume-weighted average particle size of 8.0 μm. After the particle size was verified to be qualified, the particles were annealed at 80°C for 1 h and then cooled to 23°C in the furnace. The fine particles were replaced with P34HB fine particles prepared according to steps 1 to 6 of the aforementioned "Preparation of P34HB Fine Particles", wherein the polyvinyl alcohol water in step 2 was used instead of P34HB fine particles. The solution mass fraction was 0.5%, the solid content of the P34HB aqueous phase coarse dispersion slurry in step 3 was 8.0%, the homogenization pressure in step 4 was 40 MPa, and homogenization was performed twice to obtain P34HB fine particles with a volume-weighted average particle size of 1.20 μm. After the particle size was retested and found to be qualified, the particles were annealed at 45℃ for 1 h and then placed at 23℃ for 24 h. The obtained multi-peaked particles had a coarse particle group volume-weighted average particle size of 8.0 μm and a fine particle group volume-weighted average particle size of 1.20 μm, with a coarse particle group to fine particle group mass ratio of 60:40. 10 0.10μm, D 50 It is 6.0 μm, D 90The peak size was 25.0 μm, peak position 1 was 0.25 μm, peak position 2 was 8.0 μm, crystallinity was 42%, and the main melting peak temperature was 151.1 °C. The hydrophobic modification steps were the same as in Example 1. In the weathering treatment conditions, the amount of weathering protective layer was 1.4% based on the dry weight of the particles, the mass ratio of HALS to UVA was 6:5, the nano zinc oxide accounted for 35% of the total mass of the weathering protective layer, the dry pretreatment temperature was 55 °C, and the dry pretreatment time was 10 min, thus obtaining the bio-based hydrophobic multi-peak crystalline particle additive sample of Example 8.

[0113] Finished coating sample: By weight, weigh 60 parts of silicone-modified acrylic emulsion, 18 parts of reflective component, 8 parts of heat-insulating filler, 3 parts of bio-based hydrophobic multi-peaked crystalline particles (using the bio-based hydrophobic multi-peaked crystalline particle additive sample from Example 8), 2.5 parts of functional additives, including 0.8571 parts of dispersant, 0.2143 parts of wetting agent, 0.1429 parts of defoamer, 0.1429 parts of leveling agent, 0.5714 parts of thickener, 0.1429 parts of preservative, and 0.4286 parts of film-forming aid, and 18 parts of water; the mass ratio of the bio-based hydrophobic multi-peaked crystalline particles to the aqueous film-forming base material, based on solid content, is 0.050. During preparation, in step 1, the material was sheared and dispersed at 1800 r / min for 12 min; in step 2, it was stirred at 300 r / min for 8 min; in step 3, it was stirred at 180 r / min for 8 min; in step 4, it was dispersed at 180 r / min for 12 min, and the maximum material temperature was controlled at 50℃; in step 5, it was stirred for 12 min and then filtered and packaged; the rest was consistent with the finished coating sample of Example 1.

[0114] Example 9:

[0115] The preparation of the bio-based hydrophobic multi-peak crystalline particle additive sample was the same as in Example 1, except that: in the preparation of PHB coarse particles, the classifier wheel speed in step 2 was 2200 r / min, and the feed rate was 2.8 kg / h, resulting in PHB coarse particles with a volume-weighted average particle size of 30.0 μm. After the particle size was verified to be qualified, the particles were annealed at 80℃ for 8 h and then cooled to 23℃ in the furnace. In the preparation of PHBV fine particles, the mass fraction of the polyvinyl alcohol aqueous solution in step 2 was 0.8%, and in step 3... The PHBV aqueous phase coarse dispersion slurry had a solid content of 4.0%. In step 4, the homogenization pressure was 100 MPa, and homogenization was performed 8 times to obtain PHBV fine particles with a volume-weighted average particle size of 0.10 μm. After the particle size was verified to be acceptable, the particles were annealed at 55℃ for 4 hours and then placed at 23℃ for 24 hours. The obtained multi-peaked particles had a coarse particle group volume-weighted average particle size of 30.0 μm and a fine particle group volume-weighted average particle size of 0.10 μm, with a coarse particle group to fine particle group mass ratio of 75:25. 10 It is 0.12μm, D 50 It is 9.8 μm, D 90The peak size was 34.8 μm, peak position 1 was 0.30 μm, peak position 2 was 12.9 μm, crystallinity was 70%, and the main melting peak temperature was 176.2 °C. The hydrophobic modification steps were the same as in Example 1. In the weathering treatment conditions, the amount of weathering protective layer was 2.0% based on the dry weight of the particles, the mass ratio of HALS to UVA was 1:1, the nano zinc oxide accounted for 45% of the total mass of the weathering protective layer, the dry pretreatment temperature was 65 °C, and the dry pretreatment time was 15 min, thus obtaining the bio-based hydrophobic multi-peak crystalline particle additive sample of Example 9.

[0116] Finished coating sample: By weight, weigh 20 parts of silicone-modified acrylic emulsion, 28 parts of reflective component, 12 parts of heat-insulating filler, 12 parts of bio-based hydrophobic multi-peaked crystalline particles (using the bio-based hydrophobic multi-peaked crystalline particle additive sample of Example 9), 4.5 parts of functional additives, including 1.5429 parts of dispersant, 0.3857 parts of wetting agent, 0.2571 parts of defoamer, 0.2571 parts of leveling agent, 1.0286 parts of thickener, 0.2571 parts of preservative, and 0.7714 parts of film-forming aid, and 26 parts of water; the mass ratio of the bio-based hydrophobic multi-peaked crystalline particles to the aqueous film-forming base material, based on solid content, is 0.600. During preparation, in step 1, the material was sheared and dispersed at 2400 r / min for 20 min; in step 2, it was stirred at 500 r / min for 12 min; in step 3, it was stirred at 300 r / min for 10 min; in step 4, it was dispersed at 450 r / min for 25 min, and the maximum material temperature was controlled at 50℃; in step 5, it was stirred for 14 min and then filtered and packaged; the rest was consistent with the finished coating sample of Example 1.

[0117] Comparative Example 1:

[0118] Bio-based hydrophobic multimodal crystalline particle additive sample: The bio-based hydrophobic multimodal crystalline particle additive sample used for coating formulation is consistent with Example 1, with a coarse particle group volume-weighted average particle size of 12.6 μm, a fine particle group volume-weighted average particle size of 0.33 μm, and a coarse particle group to fine particle group mass ratio of 75:25. 10 It is 0.12μm, D 50 It is 8.5μm, D 90 The peak size was 30.2 μm, peak position 1 was 0.33 μm, peak position 2 was 9.8 μm, crystallinity was 56%, the main melting peak temperature was 168.4 °C, and the hydrophobic modification conditions and weathering treatment conditions were the same as in Example 1.

[0119] Finished coating sample: By weight, 45 parts of silicone-modified acrylic emulsion, 20 parts of reflective component, 5 parts of heat-insulating filler, 2 parts of bio-based hydrophobic multimodal crystalline particles (using the bio-based hydrophobic multimodal crystalline particle additive sample of Comparative Example 1), 3.5 parts of functional additives, including 1.20 parts of dispersant, 0.30 parts of wetting agent, 0.20 parts of defoamer, 0.20 parts of leveling agent, 0.80 parts of thickener, 0.20 parts of preservative, and 0.60 parts of film-forming aid, and 18 parts of water; the mass ratio of the bio-based hydrophobic multimodal crystalline particles to the aqueous film-forming base material, based on solid content, is 0.044. The preparation steps of the finished coating sample are the same as those of the finished coating sample in Example 1.

[0120] Comparative Example 2

[0121] Bio-based hydrophobic multi-peak crystalline particle additive sample: The bulk particle size parameters of PHB coarse particles and PHBV fine particles are consistent with those of Example 1, i.e., the volume-weighted average particle size of the coarse particle group is 12.6 μm, the volume-weighted average particle size of the fine particle group is 0.33 μm, and the mass ratio of coarse particles to fine particles is 75:25. 10 It is 0.12μm, D 50 It is 8.5μm, D 90 The peak size was 30.2 μm, peak position 1 was 0.33 μm, and peak position 2 was 9.8 μm. The difference was that after mixing coarse PHB particles and fine PHBV particles at a mass ratio of 75:25 and retesting the particle size, no annealing treatment was performed. Instead, the particles were rapidly cooled with liquid nitrogen and then directly freeze-dried. Low crystallinity particles with a crystallinity of 35% and a main melting peak temperature of 146.8℃ as determined by DSC were selected. The remaining hydrophobic modification conditions, HALS to UVA mass ratio, nano zinc oxide mass fraction, and weather-resistant protective layer dosage were consistent with those in Example 1, resulting in the bio-based hydrophobic multi-peak crystalline particle additive sample of Comparative Example 2.

[0122] Finished coating sample: By weight, 39.5 parts of silicone-modified acrylic emulsion, 22 parts of reflective component, 6 parts of heat-insulating filler, 8 parts of bio-based hydrophobic multimodal crystalline particles (using the bio-based hydrophobic multimodal crystalline particle additive sample from Comparative Example 2), 3.5 parts of functional additives, including 1.20 parts of dispersant, 0.30 parts of wetting agent, 0.20 parts of defoamer, 0.20 parts of leveling agent, 0.80 parts of thickener, 0.20 parts of preservative, and 0.60 parts of film-forming aid, and 21 parts of water. The preparation steps of the finished coating sample are the same as those of the finished coating sample in Example 1.

[0123] Comparative Example 3:

[0124] Bio-based hydrophobic multi-peak crystalline particle additive sample: The particle size and thermal parameters are consistent with those of Example 1, namely, the volume-weighted average particle size of the coarse particle group is 12.6 μm, the volume-weighted average particle size of the fine particle group is 0.33 μm, and the mass ratio of coarse to fine particles is 75:25. 10 It is 0.12μm, D 50 It is 8.5μm, D 90 The peak diameter was 30.2 μm, peak position 1 was 0.33 μm, peak position 2 was 9.8 μm, crystallinity was 56%, and the main melting peak temperature was 168.4 °C. The hydrophobic modification conditions were the same as in Example 1. The difference was that the amount of weather-resistant protective layer was changed to 0.5% based on the dry weight of the particles, while the other weather-resistant treatment conditions were the same as in Example 1, resulting in the bio-based hydrophobic multi-peak crystalline particle additive sample of Comparative Example 3.

[0125] Finished coating sample: By weight, 39.5 parts of silicone-modified acrylic emulsion, 22 parts of reflective component, 6 parts of heat-insulating filler, 8 parts of bio-based hydrophobic multimodal crystalline particles (using the bio-based hydrophobic multimodal crystalline particle additive sample from Comparative Example 3), 3.5 parts of functional additives, including 1.20 parts of dispersant, 0.30 parts of wetting agent, 0.20 parts of defoamer, 0.20 parts of leveling agent, 0.80 parts of thickener, 0.20 parts of preservative, and 0.60 parts of film-forming aid, and 21 parts of water. The preparation steps of the finished coating sample are the same as those of the finished coating sample in Example 1.

[0126] Comparative Example 4:

[0127] Bio-based hydrophobic multi-peak crystalline particle additive sample: In the preparation of PHB coarse particles, the classifier rotation speed in step 2 was 1800 r / min, and the feed rate was 3.0 kg / h, yielding PHB coarse particles with a volume-weighted average particle size of 33.5 μm. In the preparation of PHBV fine particles, the mass fraction of polyvinyl alcohol aqueous solution in step 2 was 0.8%, the solid content of the PHBV aqueous phase coarse dispersion slurry in step 3 was 4.0%, and the homogenization pressure in step 4 was 105 MPa, with 8 homogenization cycles, yielding PHBV fine particles with a volume-weighted average particle size of 0.08 μm. The obtained multi-peak particles showed a coarse particle group volume-weighted average particle size of 33.5 μm and a fine particle group volume-weighted average particle size of 0.08 μm, with a coarse particle group to fine particle group mass ratio of 90:10. 10 It is 0.08μm, D 50 It is 12.0 μm, D 90 The peak size was 38.2 μm, peak position 1 was 0.22 μm, and peak position 2 was 14.6 μm; the remaining crystallinity, main melting peak temperature, hydrophobic modification conditions and weathering treatment conditions were consistent with those of Example 1, and the bio-based hydrophobic multi-peak crystalline particle additive sample of Comparative Example 4 was obtained.

[0128] Finished coating sample: By weight, 39.5 parts of silicone-modified acrylic emulsion, 22 parts of reflective component, 6 parts of heat-insulating filler, 8 parts of bio-based hydrophobic multimodal crystalline particles (using the bio-based hydrophobic multimodal crystalline particle additive sample from Comparative Example 4), 3.5 parts of functional additives, including 1.20 parts of dispersant, 0.30 parts of wetting agent, 0.20 parts of defoamer, 0.20 parts of leveling agent, 0.80 parts of thickener, 0.20 parts of preservative, and 0.60 parts of film-forming aid, and 21 parts of water. The preparation steps of the finished coating sample are the same as those of the finished coating sample in Example 1.

[0129] Comparative Example 5:

[0130] Bio-based hydrophobic multimodal crystalline particle additive sample: The bio-based hydrophobic multimodal crystalline particle additive sample used for coating formulation is consistent with Example 1, with a coarse particle group volume-weighted average particle size of 12.6 μm, a fine particle group volume-weighted average particle size of 0.33 μm, and a coarse particle group to fine particle group mass ratio of 75:25. 10 It is 0.12μm, D 50 It is 8.5μm, D 90 The peak size was 30.2 μm, peak position 1 was 0.33 μm, peak position 2 was 9.8 μm, crystallinity was 56%, the main melting peak temperature was 168.4 °C, and the hydrophobic modification conditions and weathering treatment conditions were the same as in Example 1.

[0131] Finished coating sample: By weight, 20 parts of silicone-modified acrylic emulsion, 22 parts of reflective component, 6 parts of heat-insulating filler, 13 parts of bio-based hydrophobic multimodal crystalline particles (using the bio-based hydrophobic multimodal crystalline particle additive sample of Comparative Example 5), 3.5 parts of functional additives, including 1.20 parts of dispersant, 0.30 parts of wetting agent, 0.20 parts of defoamer, 0.20 parts of leveling agent, 0.80 parts of thickener, 0.20 parts of preservative, and 0.60 parts of film-forming aid, and 21 parts of water; the mass ratio of the bio-based hydrophobic multimodal crystalline particles to the aqueous film-forming base material, based on solid content, is 0.650. The preparation steps of the finished coating sample are the same as those of the finished coating sample in Example 1.

[0132] Comparative Example 6:

[0133] Bio-based hydrophobic multi-peak crystalline particle additive sample: The particle size and thermal parameters are consistent with those of Example 1, namely, the volume-weighted average particle size of the coarse particle group is 12.6 μm, the volume-weighted average particle size of the fine particle group is 0.33 μm, and the mass ratio of coarse to fine particles is 75:25. 10 It is 0.12μm, D 50 It is 8.5μm, D 90The peak diameter was 30.2 μm, peak position 1 was 0.33 μm, peak position 2 was 9.8 μm, crystallinity was 56%, and the main melting peak temperature was 168.4 °C. The hydrophobic modification conditions were the same as in Example 1. The difference was that the amount of weather-resistant protective layer was changed to 3.0% based on the dry weight of the particles, while the other weather-resistant treatment conditions were the same as in Example 1, resulting in the bio-based hydrophobic multi-peak crystalline particle additive sample of Comparative Example 6.

[0134] Finished coating sample: By weight, 39.5 parts of silicone-modified acrylic emulsion, 22 parts of reflective component, 6 parts of heat-insulating filler, 8 parts of bio-based hydrophobic multimodal crystalline particles (using the bio-based hydrophobic multimodal crystalline particle additive sample from Comparative Example 6), 3.5 parts of functional additives, including 1.20 parts of dispersant, 0.30 parts of wetting agent, 0.20 parts of defoamer, 0.20 parts of leveling agent, 0.80 parts of thickener, 0.20 parts of preservative, and 0.60 parts of film-forming aid, and 21 parts of water. The preparation steps of the finished coating sample are the same as those of the finished coating sample in Example 1.

[0135] Comparative Example 7:

[0136] Bio-based hydrophobic multi-peak crystalline particle additive sample: The particle size and thermal parameters are consistent with those of Example 1, namely, the volume-weighted average particle size of the coarse particle group is 12.6 μm, the volume-weighted average particle size of the fine particle group is 0.33 μm, and the mass ratio of coarse to fine particles is 75:25. 10 It is 0.12μm, D 50 It is 8.5μm, D 90 The peak diameter was 30.2 μm, peak position 1 was 0.33 μm, peak position 2 was 9.8 μm, crystallinity was 56%, and the main melting peak temperature was 168.4 °C. The hydrophobic modification conditions and the amount of weather-resistant protective layer were the same as in Example 1. The difference was that the mass ratio of HALS to UVA was changed to 10:6, resulting in the bio-based hydrophobic multi-peak crystalline particle additive sample of Comparative Example 7.

[0137] Finished coating sample: By weight, 39.5 parts of silicone-modified acrylic emulsion, 22 parts of reflective component, 6 parts of heat-insulating filler, 8 parts of bio-based hydrophobic multimodal crystalline particles (using the bio-based hydrophobic multimodal crystalline particle additive sample of Comparative Example 7), 3.5 parts of functional additives, including 1.20 parts of dispersant, 0.30 parts of wetting agent, 0.20 parts of defoamer, 0.20 parts of leveling agent, 0.80 parts of thickener, 0.20 parts of preservative, and 0.60 parts of film-forming aid, and 21 parts of water. The preparation steps of the finished coating sample are the same as those of the finished coating sample in Example 1.

[0138] Comparative Example 8:

[0139] Bio-based hydrophobic multi-peak crystalline particle additive sample: The particle size and thermal parameters are consistent with those of Example 1, namely, the volume-weighted average particle size of the coarse particle group is 12.6 μm, the volume-weighted average particle size of the fine particle group is 0.33 μm, and the mass ratio of coarse to fine particles is 75:25. 10 It is 0.12μm, D 50 It is 8.5μm, D 90 The peak diameter was 30.2 μm, peak position 1 was 0.33 μm, peak position 2 was 9.8 μm, crystallinity was 56%, and the main melting peak temperature was 168.4 °C. The hydrophobic modification conditions, HALS to UVA mass ratio, and weather-resistant protective layer dosage were the same as in Example 1. The difference was that no inorganic UV shielding agent was added during the weathering treatment, resulting in the bio-based hydrophobic multi-peak crystalline particle additive sample of Comparative Example 8.

[0140] Finished coating sample: By weight, 39.5 parts of silicone-modified acrylic emulsion, 22 parts of reflective component, 6 parts of heat-insulating filler, 8 parts of bio-based hydrophobic multimodal crystalline particles (using the bio-based hydrophobic multimodal crystalline particle additive sample of Comparative Example 8), 3.5 parts of functional additives, including 1.20 parts of dispersant, 0.30 parts of wetting agent, 0.20 parts of defoamer, 0.20 parts of leveling agent, 0.80 parts of thickener, 0.20 parts of preservative, and 0.60 parts of film-forming aid, and 21 parts of water. The preparation steps of the finished coating sample are the same as those of the finished coating sample in Example 1.

[0141] Comparative Example 9:

[0142] Bio-based hydrophobic multi-peak crystalline particle sample: The bulk of PHB coarse particles and PHBV fine particles used were the same as in Example 1. The volume-weighted average particle size of the coarse particle group was 12.6 μm, and the volume-weighted average particle size of the fine particle group was 0.33 μm. The mass ratio of coarse particles to fine particles was 75:25. 10 It is 0.12μm, D 50 It is 8.5μm, D 90 The particle size distribution was 30.2 μm, peak position 1 was 0.33 μm, peak position 2 was 9.8 μm, crystallinity was 56%, and the main melting peak temperature was 168.4 °C. The two were mixed at a ratio of 75:25, and stearic acid was added at only 2.0% of the total particle mass. The mixture was stirred at 65 °C and 600 r / min for 10 min to obtain hydrophobically modified multi-peak crystalline particles. However, no surface weathering treatment or dry pretreatment was performed, resulting in the bio-based hydrophobic multi-peak crystalline particle sample of Comparative Example 9.

[0143] Finished coating sample: By weight, weigh 39.5 parts of silicone-modified acrylic emulsion, 22 parts of reflective component, 6 parts of heat-insulating filler, 8 parts of bio-based hydrophobic multi-peaked crystalline particles (using the hydrophobic modified multi-peaked crystalline particle sample of Comparative Example 9), 3.5 parts of functional additives, including 1.20 parts of dispersant, 0.30 parts of wetting agent, 0.20 parts of defoamer, 0.20 parts of leveling agent, 0.80 parts of thickener, 0.20 parts of preservative, and 0.60 parts of film-forming aid, and 21 parts of water; HALS, UVA, and nano zinc oxide are not included in the functional additives. During preparation, steps 1 to 4 were the same as those for the finished coating sample of Example 1; in step 5, in addition to adding wetting agent, defoamer, leveling agent, thickener, preservative and film-forming aid, 0.042 parts of HALS, 0.042 parts of UVA and 0.036 parts of nano zinc oxide were added. After stirring for 15 minutes, the mixture was filtered through a 100-mesh filter and packaged to obtain the finished coating sample of Comparative Example 9.

[0144] Comparative Example 10:

[0145] Bio-based hydrophobic multi-peak crystalline particle additive sample: The particle size and thermal parameters are consistent with those of Example 1, namely, the volume-weighted average particle size of the coarse particle group is 12.6 μm, the volume-weighted average particle size of the fine particle group is 0.33 μm, and the mass ratio of coarse to fine particles is 75:25. 10 It is 0.12μm, D 50 It is 8.5μm, D 90 The peak diameter was 30.2 μm, peak position 1 was 0.33 μm, peak position 2 was 9.8 μm, crystallinity was 56%, and the main melting peak temperature was 168.4 °C. The hydrophobic modification conditions were the same as in Example 1. The difference was that the dry pretreatment temperature was changed to 85 °C, the dry pretreatment time was changed to 25 min, and other weathering treatment ratios were the same as in Example 1, resulting in the bio-based hydrophobic multi-peak crystalline particle additive sample of Comparative Example 10.

[0146] Finished coating sample: By weight, 39.5 parts of silicone-modified acrylic emulsion, 22 parts of reflective component, 6 parts of heat-insulating filler, 8 parts of bio-based hydrophobic multimodal crystalline particles (using the bio-based hydrophobic multimodal crystalline particle additive sample of Comparative Example 10), and 3.5 parts of functional additives were weighed, including 1.20 parts of dispersant, 0.30 parts of wetting agent, 0.20 parts of defoamer, 0.20 parts of leveling agent, 0.80 parts of thickener, 0.20 parts of preservative, and 0.60 parts of film-forming aid, and 21 parts of water. During preparation, steps 1, 2, 3, and 5 were the same as the finished coating sample of Example 1; in step 4, dispersion was still carried out at 300 r / min for 20 min, but the maximum material temperature was controlled at 58℃, resulting in the finished coating sample of Comparative Example 10.

[0147] Application examples

[0148] Unless otherwise specified, all tests were conducted at 23±2℃ and 50±5% relative humidity. The results of quantitative indicators were the arithmetic mean of three parallel samples or three independent replicates. The qualitative grading indicators were determined according to the mode of the three results as specified in this instruction manual. If there was no unique mode, the higher grade was taken as the final result.

[0149] Application Example 1: Test of reflective heat insulation and stain resistance.

[0150] Select the finished coating samples prepared in Examples 1 to 9 and Comparative Examples 1 to 10 respectively, and take no less than 500g of each sample and place them in a clean polyethylene container. After standing for 24 hours at 23±2℃ and 50±5% relative humidity, stir slowly at 300r / min for 5 minutes to make the sample reach a uniform state.

[0151] Samples were applied to the surface of a 150mm×75mm×4mm asbestos-free fiber cement board using a wire-bar coating method. The wet film thickness was controlled at 800±20μm, and six samples were prepared for each sample. All samples were cured at 23±2℃ and 50±5% relative humidity for 7 days, and then equilibrated in the same environment for 24 hours after curing.

[0152] The six fiber cement board samples for each sample were divided into two groups, A and B, with three samples in each group. Group A was used for initial SRI and SRI retention rate tests after 2000h xenon arc aging: first, the solar reflectance and hemispherical emissivity were measured according to the methods described above in "Solar Reflectance, Hemispherical Emissivity, SRI, SRI after Washing and SRI Retention Rate after 2000h Xenon Arc Aging". The solar reflectance was measured using an ultraviolet-visible-near-infrared spectrophotometer with an integrating sphere in the 300nm to 2500nm wavelength range. Three different locations were tested for each sample and the average value was taken.

[0153] The hemispherical emissivity was measured using a surface emissivity meter at 23±2℃. Three different locations were tested for each sample and the average value was taken.

[0154] The initial SRI was calculated accordingly. Then, the same set of samples were placed in a Ci4400 xenon arc aging test chamber and aged for 2000 h under the following conditions: irradiance at 340 nm (0.35±0.02) W / (m²·nm), black panel temperature (65±3)℃, and relative humidity (50±5)%. The SRI after aging was then measured, and the SRI retention rate was calculated. Group B was used for testing the contamination resistance rating, dust accumulation at 80℃, and SRI after rinsing: the samples were first treated in an 80℃ forced-air drying oven for 30 min, and then 0.50 g of simulated contamination powder, prepared from carbon black N330, 325 mesh talc powder, and 500 mesh quartz powder in a mass ratio of 1:1:1, was evenly spread over a 100 mm × 50 mm test area.

[0155] After standing for 10 minutes, the sample was horizontally vibrated for 30 seconds at 100 vibrations / min and an amplitude of 5 mm. The sample was then inverted to remove unattached powder. The mass before and after dust attachment was recorded, and the amount of dust attached was calculated. The sample surface was then rinsed twice with 250 mL of deionized water within 15 seconds and allowed to air dry for 2 hours. The SRI after rinsing was then measured according to the methods described in "Solar Reflectance, Hemispherical Emissivity, SRI, SRI after Rinsing, and SRI Retention Rate after 2000 hours of Xenon Arc Aging." The SRI resistance was evaluated according to the standards described in "Stain Resistance Grade and Dust Attachment at 80℃." The corresponding data are shown in Table 3.

[0156] Table 3. Test results of reflective heat insulation and stain resistance of the examples and comparative examples.

[0157]

[0158] Analysis: As shown in Table 3, the initial SRI of Examples 1 to 9 ranged from 103.8 to 113.4. After 2000 hours of xenon arc aging, the SRI retention rate was 94.2% to 95.6%, the dust accumulation at 80°C was 0.98 g / m² to 1.20 g / m², and the SRI after rinsing was 102.4 to 108.6, with a stain resistance rating of 1 for all examples. For Comparative Examples 1 to 10, after 2000 hours of xenon arc aging, the SRI retention rate was 88.3% to 92.6%, the dust accumulation at 80°C was 1.29 g / m² to 2.85 g / m², and the stain resistance rating was 2 to 3. These results indicate that under the particle dosage, particle size distribution, crystallinity, and surface weathering treatment conditions specified in this application, the coating exhibits more stable performance in terms of reflectance retention and stain resistance. Comparative Example 1 corresponds to a low particle / matrix mass ratio; Comparative Example 2 corresponds to low particle crystallinity and main melting peak temperature; Comparative Example 4 corresponds to an imbalance in coarse and fine particle size structure; Comparative Example 5 examines the particle / matrix mass ratio exceeding the upper limit rather than changes in the particle additive itself; Comparative Example 9 corresponds to a non-surface loading method; Comparative Example 10 corresponds to high pretreatment and dispersion temperatures. The above factors correspond to a decrease in reflectivity retention and anti-fouling performance.

[0159] Application Example 2: Mechanical properties, impermeability, water resistance, and environmental performance testing.

[0160] Select at least 300g of the finished coating samples prepared in Examples 1 to 9 and Comparative Examples 1 to 10 respectively, place them in a clean polyethylene container, let them stand for 24 hours at 23±2℃ and 50±5% relative humidity, and then stir slowly at 300r / min for 5 minutes.

[0161] Samples were applied to the surface of a 150mm×75mm×2mm polytetrafluoroethylene (PTFE) release liner using a wire-bar coating method, with a wet film thickness controlled at 800±20μm. Three samples were prepared for each sample. Separately, samples were applied to the surface of a 150mm×75mm×4mm asbestos-free fiber cement board, with a wet film thickness controlled at 800±20μm. Three samples were prepared for each sample for impermeability testing. The PTFE release liner samples were cured at 23±2℃ and 50±5% relative humidity for 7 days, then the free film was peeled off from the release liner and equilibrated in the same environment for 24 hours before testing. The fiber cement board samples were directly used for impermeability testing after curing for 7 days. When all three samples met the requirement of no water seepage, no water droplets, and no damp marks on the back side, it was recorded as "0.30MPa, 30min impermeability". If any one sample did not meet this requirement, the number of unqualified samples was recorded.

[0162] For static water contact angle testing, a cured and equilibrated free membrane was used, with the air contact surface as the test surface. The OCA20 contact angle meter listed in Table 2 was used for testing. The titrant was deionized water with a resistivity of not less than 18.2 MΩ·cm, with a single drop volume of 3.0 μL. After the droplet fell onto the membrane surface, it was allowed to stand for 5 seconds, and the left and right contact angles were read, with the average value taken as the result for that measurement point. Three free membrane samples were taken for each sample, and three different locations were tested on each sample. The arithmetic mean of the nine measurement points was taken as the test result for that sample. Tensile strength and elongation at break were tested according to GB / T16777-2008 and the conditions specified in this instruction manual: the free membrane was cut into Type I dumbbell-shaped specimens with an effective gauge length of 25 mm and an effective narrow section width of 6 mm. The tensile speed was 500 mm / min. Before testing, the thickness was measured at 3 points within the effective area and the average value was taken. The tensile strength was calculated by dividing the maximum tensile force by the initial effective cross-sectional area of ​​the specimen. The elongation at break was calculated as "increase in gauge spacing at break / initial gauge length × 100%". Each sample had no fewer than 5 effective specimens. Water impermeability was tested according to the aforementioned method. For water resistance testing, a 50 mm × 120 mm specimen of the free membrane was cut and immersed in deionized water at (23 ± 2) °C for 168 h. After removal, the surface water was absorbed with filter paper, and the specimen was placed at room temperature for 1 h before visual observation. For the total fluoride test, the cured film was pulverized and passed through a 60-mesh sieve. The fluoride ion concentration was determined using the oxygen bomb combustion-ion chromatography method described in the previous section on "Total Fluoride Content," and the total fluoride content was calculated accordingly. The water resistance qualification standard is: no blistering, no peeling, and no cracking. The corresponding data are shown in Table 4.

[0163] Table 4. Test results of mechanical properties, impermeability, water resistance, and environmental performance of the examples and comparative examples.

[0164]

[0165] Analysis: As shown in Table 4, the static water contact angles of Examples 1 to 9 ranged from 123° to 129°, the tensile strengths from 3.0 MPa to 3.6 MPa, and the elongation at break from 305% to 338%. The impermeability of Examples 1 to 9 and Comparative Examples 1 to 10 was 0.30 MPa, with impermeability for 30 minutes and no blistering, peeling, or cracking for 168 hours. The total fluoride content was below 5.0 mg / kg. In Comparative Example 1, the static water contact angle decreased to 101° when the particle / matrix mass ratio was low. In Comparative Example 2, the tensile strength and elongation at break decreased simultaneously when the particle crystallinity and main melting peak temperature were low. Although Comparative Example 5 achieved a static water contact angle of 130°, the tensile strength decreased to 2.6 MPa and the elongation at break decreased to 242%, indicating that simply increasing the particle content does not necessarily lead to better overall performance. Overall, the embodiments maintain a relatively balanced state between hydrophobicity, mechanical properties, water resistance and environmental indicators.

[0166] Application Example 3: Verification of thermal parameters and surface weather-resistant protective layer of bio-based hydrophobic multi-peak crystalline particles.

[0167] Bio-based hydrophobic multi-peaked crystalline particle bodies corresponding to Examples 1 to 9 and Comparative Examples 1 to 10 were selected as DSC test samples; corresponding bio-based hydrophobic multi-peaked crystalline particle additives or particle samples were selected as UVA surface retention rate test samples and 80℃ particle morphology retention rate test samples. Each sample was taken in portions of no less than 20g, placed in a sealed sample bottle, and equilibrated for 12h at 23±2℃ and 50±5% relative humidity before testing. The crystallinity / % and main melting peak temperature / ℃ in Table 5 refer to the test results of the corresponding bio-based hydrophobic multi-peaked crystalline particle bodies.

[0168] For DSC testing, 5.0 ± 0.5 mg of each sample was weighed, placed in a sealed aluminum crucible, and tested under nitrogen flow rate of 50 mL / min according to the procedure of "raising from 25℃ to 200℃, holding for 3 min, then lowering to -20℃ at 10℃ / min, and then raising to 200℃ at 10℃ / min". For the bulk sample of the mixed particles, the main melting peak temperature of the second heating curve was directly read. The crystallinity was determined by the method described above in "Main Melting Peak Temperature, Enthalpy of Melting, and Crystallinity" from the X values ​​of each individual particle constituting the mixed particles measured under the same DSC conditions. c,i Calculated using a weighted average of quality scores.

[0169] For the UVA surface retention rate test, 0.50 g of each sample was weighed and added to 50.0 mL of anhydrous ethanol, and stirred for 30 min at 25 °C and 300 r / min.

[0170] The sample was then centrifuged at 6080×g for 10 min. The supernatant was filtered through a 0.22 μm polytetrafluoroethylene filter membrane, and the absorbance was measured at 343 nm. A series of standard solutions with concentrations of 0.5 mg / L, 1.0 mg / L, 2.0 mg / L, 4.0 mg / L, 6.0 mg / L, and 8.0 mg / L were prepared using Tinuvin 328 ethanol standard solution, and the absorbance was measured at 343 nm. A linear regression was performed on the absorbance against the mass concentration, and the correlation coefficient R² was not less than 0.999.

[0171] After correcting with anhydrous ethanol as a blank, the UVA content in the filtrate was converted, and then the UVA surface retention rate was calculated according to the formula described in the "particle surface UVA retention rate" above.

[0172] When testing the particle morphology retention rate at 80℃, take 0.50g of each sample and spread it evenly in a glass dish with a diameter of 60mm. Treat it in an 80℃ forced-air oven for 2h. After cooling, use a digital microscope to randomly photograph 10 fields of view at 200x magnification. Each field of view contains no less than 100 particles.

[0173] Fine particle samples were fixed to an aluminum sample stage using conductive carbon adhesive without metal sputtering. They were observed using a field emission scanning electron microscope (FET) as listed in Table 2 in low vacuum mode, with an accelerating voltage of 5.0 kV, a working distance of 8 mm to 10 mm, and a magnification of 10,000x. Ten fields of view were randomly selected, and at least 200 particles were counted in each field. Particles with complete outlines were counted according to the criteria described in "80℃ Particle Morphology Retention Rate," and the morphology retention rate was calculated. The corresponding data are shown in Table 5.

[0174] Table 5. Thermal parameters and surface weather-resistant protective layer test results of the examples and comparative examples.

[0175]

[0176] In Comparative Example 8, no inorganic UV shielding agent was introduced, so "Inorganic UV shielding agent mass fraction / %" was recorded as "-"; in Comparative Example 9, HALS, UVA, and nano zinc oxide were directly added to the system in step 5 without forming a weather-resistant protective layer, so "HALS:UVA", "Inorganic UV shielding agent mass fraction / %", "Weather-resistant protective layer dosage / %", and "UVA surface retention rate / %" were all recorded as "-".

[0177] Analysis: As shown in Table 5, the crystallinity of Examples 1 to 9 ranges from 40% to 70%, the main melting peak temperature ranges from 150.6℃ to 176.2℃, the UVA surface retention rate ranges from 82% to 92%, and the particle morphology retention rate at 80℃ ranges from 90% to 98%. This indicates that under the preset thermal window and surface loading conditions, the particles exhibit good thermal morphology stability and surface weather-resistant component retention ability. Although the HALS:UVA mass ratio, inorganic UV shielding agent mass fraction, and weather-resistant protective layer dosage are the same as in Example 1 in Comparative Example 2, the particle morphology retention rate at 80℃ drops to 68% due to the decrease in crystallinity and main melting peak temperature. In Comparative Example 3, the UVA surface retention rate decreases due to the decrease in the amount of weather-resistant protective layer. In Comparative Example 6, the UVA surface retention rate increases due to the increase in the amount of weather-resistant protective layer, but the particle morphology retention rate at 80℃ does not further improve. Comparative Examples 9 and 10 respectively reflect the adverse effects of non-surface loading methods and excessively high pretreatment temperatures and times on the stability of the surface weather-resistant protective layer. This result indicates that the particle thermal parameters and the state of the surface weather-resistant protective layer must be matched together in order to maintain good surface structural stability.

[0178] Application Example 4: Verification of formulation boundaries and construction stability.

[0179] Three batches of finished coating samples were independently prepared according to the formulations and processes described in Examples 1 to 9 and Comparative Examples 1 to 10, and the obtained samples were used as the verification objects for formulation boundaries and construction stability.

[0180] Immediately after dispersion in step 1, the fineness of the reflective slurry was measured using a scraper fineness meter. Each sample was measured three times, and the average value was taken. After step 5 and before filtration, the application viscosity was measured at 25°C using a KU-3 Stormer viscometer. Each sample was measured three times, and the average value was taken. For the 100-mesh sieve residue test, 200g of each sample was filtered through a 100-mesh nylon filter at 25°C. The residue on the filter was dried at 60°C for 30 minutes and then weighed. For the surface defect count test, the filtered sample was prepared into a slab according to the method described in "Coating Preparation and Sample Curing" and cured for 7 days. Then, the surface defect count was counted according to the method described in "100-mesh sieve residue, surface defect count, and 80°C softening and leveling grade". Each sample was prepared in three independent batches, and the final result was the arithmetic mean of the three independent batches. The corresponding data are shown in Table 6.

[0181] Table 6. Boundary and construction stability test results of the examples and comparative examples.

[0182]

[0183] Analysis: Based on the preparation descriptions of each embodiment and comparative example, and Table 6, it can be seen that in Examples 1 to 9, when the mass ratio of bio-based hydrophobic multi-peak crystalline particles to aqueous film-forming base material is 0.050 to 0.600, the fineness of the reflective slurry is 28 μm to 39 μm, the application viscosity is 70 KU to 130 KU, the residue on a 100-mesh sieve is 0.12 g to 0.29 g, and the number of surface defects is 0 / 100 cm² to 1 / 100 cm². This indicates that the system has good dispersibility, filtration permeability, and application stability within the boundaries of this formulation. Comparative Example 1, with a particle / base material mass ratio below the lower limit, showed a decline in performance, although the construction stability index remained at a good level. Comparative Example 5 used the same particle additive as Example 1, with the only difference being an increase in the amount of particles added to the coating formulation, raising the particle / base material mass ratio to 0.650. At this point, the residue on a 100-mesh sieve increased to 0.44g, and the number of surface defects increased to 2 per 100cm², indicating that construction stability began to deteriorate when the particle / base material mass ratio exceeded the upper limit. In Comparative Example 10, the residue on a 100-mesh sieve and the number of surface defects increased significantly when the temperature window was exceeded, indicating that both the particle / base material mass ratio and heat treatment conditions affect construction stability.

[0184] Application Example 5: Validation of dry pretreatment and dispersion temperature window.

[0185] The independent batches of samples and corresponding curing samples from Application Example 4 were continued as test objects. The dry pretreatment temperature, dry pretreatment time, and the highest material temperature in step 4 were all obtained through on-site recording. The highest material temperature in step 4 was continuously recorded throughout the dispersion process using a digital thermometer with a K-type insertion thermocouple temperature probe listed in Table 2, and the maximum value was recorded at 10-second intervals, with a temperature measurement accuracy of ±0.5℃. For the 80℃ softening and leveling grade test, the filtered sample from Application Example 4 was used to prepare a film according to the method described in "Coating Preparation and Sample Curing" and cured for 7 days. The sample was then placed in an 80℃ forced-air oven for 2 hours. After cooling to room temperature, the surface was observed with the naked eye combined with a digital microscope to check the retention of continuous bright flow marks and surface particle protrusions. The grade was determined according to the standards described in "100-mesh filtration residue, number of surface defects, and 80℃ softening and leveling grade test". Each sample was tested independently three times. The softening and leveling grade at 80℃ was taken as the mode of the three results; if there was no unique mode, the higher grade was taken as the final result. The corresponding data are shown in Table 7.

[0186] Table 7. Test results of dry pretreatment and dispersion temperature window for the examples and comparative examples.

[0187]

[0188] In the 80℃ softening and leveling grades, grade 0 indicates that there are no continuous bright flow marks and the surface particle protrusions are basically intact.

[0189] Level 1 indicates that continuous bright flow marks appear in localized areas and the leveled area accounts for no more than 10% of the total area.

[0190] Level 2 indicates the presence of obvious, continuous bright flow marks with a leveling area exceeding 10%.

[0191] Comparative Example 9 did not undergo surface loading dry pretreatment, therefore "dry pretreatment temperature / ℃" and "dry pretreatment time / min" are marked as "-".

[0192] Analysis: As shown in Table 7, in Examples 1 to 9, when the dry pretreatment temperature was 40℃ to 80℃, the dry pretreatment time was 3 min to 20 min, and the highest material temperature in step 4 did not exceed 50℃, the softening and leveling grade at 80℃ was 0, indicating that the particle protrusion structure could be well maintained within this process window. Although Comparative Example 2 had the same temperature window as Example 1, it exhibited a level 1 softening and leveling phenomenon due to the lower particle crystallinity and main melting peak temperature, indicating that particle thermal parameters also affect the high-temperature surface state. In Comparative Example 10, when the dry pretreatment temperature was 85℃, the dry pretreatment time was 25 min, and the highest material temperature in step 4 was 58℃, the softening and leveling grade at 80℃ increased to level 2, indicating that excessively high pretreatment and dispersion temperatures would weaken the high-temperature morphological stability of the system. Overall, both particle thermal parameters and the process temperature window need to be satisfied simultaneously to maintain a good high-temperature surface state.

[0193] Application Example 6: Verification of the weather resistance load of the dispersed phase and particle surface of the coating.

[0194] The finished coating samples obtained from Examples 1 to 9 and Comparative Examples 1 to 10 were selected, and fiber cement board samples were prepared according to the aforementioned coating preparation and sample curing methods. After curing for 7 days and equilibrating for 24 hours, the samples were immersed in liquid nitrogen for 5 minutes and then fractured. The fracture surface samples were fixed on an aluminum sample stage and sputter-coated with gold for 60 seconds before observation using a field emission scanning electron microscope (FET) as listed in Table 2. The FET observation voltage was 5.0 kV, the working distance was 8 mm to 10 mm, and the magnification was 3000x. Five cross-sectional fields of view were randomly selected for each sample, each with an area of ​​100 μm × 75 μm. ImageJ software was used to perform threshold segmentation of the PHA particle phase, and the projected area of ​​all PHA particle phases and the projected area of ​​the single largest continuous PHA particle phase were statistically analyzed. The area ratio of the largest continuous PHA phase was calculated using the aforementioned method. Simultaneously, the Zn element on the particle surface was scanned using an energy dispersive spectroscopy (EDS) instrument paired with the FET, and the Zn element surface coverage was statistically analyzed. The corresponding data are shown in Table 8.

[0195] Table 8. Verification results of the particulate dispersion and surface weather resistance load of the coatings in the examples and comparative examples.

[0196]

[0197] Analysis: As shown in Table 8, the maximum continuous PHA phase area ratio in Examples 1 to 9 ranged from 4.9% to 12.1%, all below 15.0%. Furthermore, no continuous PHA phase with a span exceeding 50% was observed in any of the five cross-sectional fields of view, indicating that the bio-based hydrophobic multi-peaked crystalline particles in Examples 1 to 9 existed as particulate dispersed phases in the coating, without forming a continuous film. The Zn element surface coverage in Examples 1 to 9 ranged from 64% to 85%. Combined with the UVA surface retention rate of no less than 82% in Application Example 3, this indicates that HALS, UVA, and nano-zinc oxide, after dry pretreatment, can form a weather-resistant protective layer on the particle surface. Comparative Example 1 used the same particle additives as Example 1, but the particle / base material mass ratio was lower, and the maximum continuous PHA phase area ratio was only 4.3%. Although no continuous film was formed, the surface microstructure was insufficient, consistent with its decreased stain resistance. Comparative Example 2 exhibits low particle crystallinity and a low main melting peak temperature. While the area ratio of the largest continuous PHA phase reaches 14.2%, it still falls short of the continuous film determination threshold. However, the particle edges show softening and blunting in the cross-section, consistent with the decrease in particle morphology retention at 80℃. Comparative Example 3 has an insufficient amount of weather-resistant protective layer, with the Zn element surface coverage dropping to 39%, indicating insufficient weather-resistant load. Comparative Example 4 shows an imbalance in particle size distribution, with the largest continuous PHA phase area ratio at 16.4%, and one field of view showing a continuous PHA phase with a width exceeding 50%, indicating locally bridged particle phases. Comparative Example 5 has a particle / matrix mass ratio exceeding the upper limit, with the largest continuous PHA phase area ratio reaching 23.6%, and three fields of view showing continuous PHA phases, indicating that excessive particles disrupt the discrete particle distribution and form locally continuous particle phases. Comparative Example 6 has an excessive amount of weather-resistant protective layer, with a Zn element surface coverage of 90%, but locally visible surface load layer enrichment does not further improve construction stability. In Comparative Example 7, the HALS / UVA ratio exceeded the range; although the particle dispersion had not deteriorated, its weather resistance decreased. In Comparative Example 8, no nano-zinc oxide was added, and the Zn element surface coverage was not detected, indicating that no nano-zinc oxide surface coverage was formed. In Comparative Example 9, HALS, UVA, and nano-zinc oxide were directly added to the coating system. The Zn element was mainly distributed as free dot-like particles in the emulsion matrix, with a Zn element surface coverage of only 9% in the particle outline area, indicating that it did not constitute a weather-resistant loading layer on the particle surface. In Comparative Example 10, due to the high dry pretreatment temperature and the highest material temperature in step 4, the maximum continuous PHA phase area ratio reached 21.7%, and a continuous PHA phase was observed in two fields of view, indicating that high-temperature treatment caused local particle agglomeration and the formation of a locally continuous particle phase. These results further demonstrate that the particle dosage, particle size structure, thermal parameters, surface weather resistance loading, and dispersion temperature window specified in this invention collectively ensure that the PHA particles in the coating film exist as a particulate dispersion phase that does not form a continuous film.

[0198] Experimental Results and Analysis

[0199] This section analyzes the influence trend of the numerical range of key components in the coating formulation and process conditions on the experimental results by combining the comprehensive test data of Examples 1 to 9 and Comparative Examples 1 to 10.

[0200] The effect of the mass ratio of bio-based hydrophobic multimodal crystalline particles to aqueous film-forming binder on coating performance was analyzed. Data showed that when the mass ratio was controlled within the range of 0.05 to 0.60, the coating exhibited good synergy between application stability and various physical properties. Specifically, the static water contact angle remained between 123° and 129°, the tensile strength reached 3.0 MPa to 3.6 MPa, and the elongation at break all exceeded 300%. If the addition amount was below the lower limit, for example, the mass ratio in Comparative Example 1 was 0.044, the surface micro-roughness of the coating was insufficient to support excellent hydrophobicity, resulting in a decrease in the static water contact angle to 101°, an increase in dust accumulation at 80°C to 2.85 g / m², and a decrease in the stain resistance level to level 3. Conversely, if the upper limit is exceeded, for example, when the mass ratio in Comparative Example 5 reaches 0.650, the excess powder affects the continuous film formation of the system, causing the tensile strength to drop to 2.6 MPa, the elongation at break to drop to 242%, and the residue on the 100-mesh filter to increase to 0.44 g with obvious surface defects, resulting in deterioration of construction stability.

[0201] The influence of bulk thermal parameters of polyhydroxyalkanoates on high-temperature morphological stability was analyzed. Data from the examples show that when the particle crystallinity is between 40% and 70% and the main melting peak temperature during secondary heating is not lower than 150°C, the particle morphology retention rate under 80°C baking conditions reaches 90% to 98%, and the softening and leveling grade of the coating film at 80°C remains at the optimal level of 0. When the thermal parameters are not up to standard, such as in Comparative Example 2 where the crystallinity is only 35% and the main melting peak temperature is 146.8°C, the particles are prone to softening under high-temperature conditions. The particle morphology retention rate at 80°C drops sharply to 68%, continuous bright flow marks appear on the coating surface, the softening and leveling grade drops to level 1, and the mechanical properties also show a slight decrease.

[0202] The effects of the mass ratio and particle size distribution of coarse and fine particles on anti-fouling and reflective heat insulation performance were analyzed. When the mass ratio of coarse to fine particles was between 60:40 and 85:15 and the particle size distribution was within the specified range, the initial solar reflectance index could reach 103.8 to 113.4, effectively inhibiting pollutant adhesion. If the multi-peak ratio was unbalanced, such as in Comparative Example 4 where the coarse-to-fine ratio reached 90:10 and the volume-weighted average particle size of coarse particles was too large to 33.5 μm, the excessive dominance of large particles led to damage to the surface density of the coating. The particle morphology retention rate at 80℃ dropped to 82%, and the dust accumulation at 80℃ increased to 1.95 g / m², resulting in a decrease in the solar reflectance index retention rate after 2000 h of xenon arc aging.

[0203] The effects of the weather-resistant protective layer formulation and preparation process on the long-term weather resistance of the coating were analyzed. When the amount of the weather-resistant protective layer accounted for 0.8% to 2.5% of the dry weight of the particles and the proportions of each component were appropriate, the surface retention rate of the UV absorber was greater than or equal to 82%, and the solar reflectance index retention rate was above 94.2% after 2000 hours of aging. If the amount of the weather-resistant layer was too low, for example, only 0.5% in Comparative Example 3, the surface retention rate of the UV absorber dropped to 71%, and the reflectance decay accelerated after aging. When the amount was too high, such as 3.0% in Comparative Example 6, although the surface retention rate was improved, the particle morphology retention rate was not further improved, resulting in waste of raw materials. In addition, the dry pretreatment temperature and dispersion temperature had a significant impact on the final coating state. If the process temperature is too high, such as in Comparative Example 10 where the pretreatment temperature reaches 85℃ and the highest dispersion temperature reaches 58℃, not only does the surface retention rate of the UV absorber drop to 68%, but it also causes premature softening and agglomeration of the particles, resulting in a sharp increase in the residue on the 100-mesh filter to 2.84g, and a deterioration in the softening and leveling grade to level 2. If a dry surface loading process is not performed but a direct mixing process is used, as in Comparative Example 9, both the solar reflectance index retention rate and morphology retention rate decrease significantly after aging.

[0204] In summary, this invention introduces annealed and crystallized coarse and fine bimodal polyhydroxyalkanoate particles into a reflective heat-insulating and waterproof system in solid powder form. It then applies fatty acid or fatty acid salt hydrophobication and HALS / UVA / nano zinc oxide dry surface loading to these particles. Furthermore, it controls the particle-to-film-forming material ratio, the amount of surface weather-resistant layer, and low-temperature dispersion conditions, ensuring that the particles remain in a dispersed phase state without forming a continuous film within the coating. Microscopic verification of the coating cross-section shows that the maximum continuous PHA phase area ratio in Examples 1 to 9 is 4.9% to 12.1%, all below 15.0%, and no continuous PHA phase with a penetration width exceeding 50% is observed. Simultaneously, the Zn element surface coverage is 64% to 85%, indicating that nano zinc oxide can form a weather-resistant protective layer on the particle surface together with HALS and UVA. Comparative Examples 4, 5, and 10 exhibited locally bridged or locally continuous particle phases due to imbalanced particle size structure, excessively high particle / matrix mass ratio, and excessively high pretreatment and dispersion temperatures, respectively. This further illustrates the necessity of the particle size structure, particle content, and process temperature window defined in this invention for maintaining the dispersed particle phase. Therefore, the coating film can simultaneously achieve a softening and leveling grade of 0 at 80°C, low dust accumulation, high solar reflectance retention rate, and good waterproof and mechanical properties, forming a stable closed-loop reflective thermal insulation and waterproof formulation.

[0205] Those skilled in the art should understand that the above embodiments are merely exemplary and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc., made to the technical solutions of the present invention within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A bio-based multi-peak crystalline particle reflective heat-insulating and waterproof coating, characterized in that, The coating, by weight, comprises the following components: The aqueous film-forming base material is 20 to 75 parts by solids content, and the aqueous film-forming base material is an organosilicon-modified acrylic emulsion; The reflective component comprises 5 to 45 parts, wherein the reflective component is composed of rutile titanium dioxide and near-infrared reflective black composite metal oxide pigment; 0.5 to 30 parts of thermal insulation filler, wherein the thermal insulation filler is hollow glass microspheres; 3 to 20 parts of bio-based hydrophobic multimodal crystalline particles; Functional additives: 0.1 to 12 parts; 5 to 45 parts water; The bio-based hydrophobic multi-peak crystalline particles are polyhydroxy fatty acid ester crystalline polyester particles added in the form of solid powder. They are obtained by compounding coarse and fine particle fractions that have undergone annealing and crystallization treatment and then hydrophobizing the surface of fatty acids or fatty acid salts. They exist as a particulate dispersion phase that does not form a continuous film in the coating film formed by the coating. The coarse particle group formed by the coarse particle fraction has a volume-weighted average particle size of 8 μm to 30 μm, the fine particle group formed by the fine particle fraction has a volume-weighted average particle size of 0.10 μm to 1.2 μm, and the mass ratio of the coarse particle group to the fine particle group is 60:40 to 85:

15. The polyhydroxy fatty acid ester matrix portion of the polyhydroxy fatty acid ester crystalline polyester particles is a polyhydroxy fatty acid ester body, the crystallinity of the polyhydroxy fatty acid ester body is 40% to 70%, and the secondary heating main melting peak temperature of the polyhydroxy fatty acid ester body measured by differential scanning calorimetry is not lower than 150°C. The coating contains an anti-UV aging component, which includes a hindered amine light stabilizer, a UV absorber, and nano zinc oxide. The bio-based hydrophobic multi-peak crystalline particles are pretreated with the hindered amine light stabilizer, the UV absorber, and the nano zinc oxide by a dry process to form a weather-resistant protective layer on the particle surface. The mass ratio of hindered amine light stabilizer to UV absorber in the weather-resistant protective layer is 0.5:1 to 8:6, and the amount of the weather-resistant protective layer is 0.8% to 2.5% based on the dry basis mass of the bio-based hydrophobic multi-peak crystalline particles. The mass ratio of the bio-based hydrophobic multi-peak crystalline particles to the aqueous film-forming matrix is ​​0.05 to 0.60 based on solid content. The bio-based hydrophobic multi-peak crystalline particles retain more than 90% of their morphology at 80℃. Furthermore, the leveling grade of the coating film formed by the coating at 80°C is 0.

2. The coating according to claim 1, characterized in that, The particle size distribution of the bio-based hydrophobic multimodal crystalline particles, measured by laser particle size distribution method, satisfies: D 10 The range is from 0.10 to 0.25 μm, D 50 The diameter is 6 to 10 μm, D 90 The range is 25 to 35 μm, and the volume distribution curve has two peaks located at 0.25 to 0.50 μm and 8 to 13 μm, respectively.

3. The coating according to claim 1, characterized in that, The hindered amine light stabilizer is a 2,2,6,6-tetramethylpiperidine derivative hindered amine light stabilizer, and the ultraviolet absorber is a benzotriazole ultraviolet absorber; the surface retention rate of the ultraviolet absorber of the bio-based hydrophobic multi-peak crystalline particles is not less than 82%; the mass fraction of the nano zinc oxide is 10% to 60% based on the total mass of the weather-resistant protective layer.

4. The coating according to claim 1, characterized in that, The polyhydroxy fatty acid ester in the polyhydroxy fatty acid ester crystalline polyester particles is selected from one or more of short-chain polyhydroxy fatty acid esters, medium- and long-chain polyhydroxy fatty acid esters, or copolymers of the above polyhydroxy fatty acid esters. The short-chain polyhydroxy fatty acid ester is selected from one or more of poly(3-hydroxybutyrate), poly(4-hydroxybutyrate), poly(3-hydroxyvalerate), poly(3-hydroxybutyrate-3-hydroxyvalerate copolyester), and poly(3-hydroxybutyrate-4-hydroxybutyrate copolyester; The medium- and long-chain polyhydroxy fatty acid esters are selected from one or more of poly(3-hydroxyhexanoate), poly(3-hydroxyheptanoate), poly(3-hydroxyoctanoate), poly(3-hydroxynonanoate), poly(3-hydroxydecanoate), poly(3-hydroxyundecanoate), poly(3-hydroxydodecanate), poly(3-hydroxytetrate), poly(3-hydroxytetradecanoate), and poly(3-hydroxybutyrate-3-hydroxyhexanoate) copolyesters; the bio-based hydrophobic multimodal crystalline particles are obtained by surface treatment of the polyhydroxy fatty acid ester crystalline polyester particles with fatty acids or fatty acid salts.

5. The coating according to claim 1, characterized in that, The coarse particle fraction is poly(3-hydroxybutyrate) coarse particles, and the fine particle fraction is poly(3-hydroxybutyrate-3-hydroxyvalerate) copolyester fine particles and / or poly(3-hydroxybutyrate-4-hydroxybutyrate) copolyester fine particles; the annealing temperature of the coarse particle fraction is 80°C and the annealing time is 1 to 8 hours, and the annealing temperature of the fine particle fraction is 45°C to 65°C and the annealing time is 0.5 to 4 hours; the functional additives include one or more of the following: dispersant, wetting agent, defoamer, leveling agent, thickener, anti-settling agent, preservative, bactericide, freeze-thaw stabilizer, film-forming aid, crosslinking agent, and coupling agent.

6. The coating according to claim 1, characterized in that, The mass ratio of the rutile titanium dioxide to the near-infrared reflective black composite metal oxide pigment is 18:

4.

7. A bio-based hydrophobic multimodal crystalline particle additive for preparing the coating according to any one of claims 1 to 6, characterized in that, It is a solid powder additive, including a coarse particle fraction that has been annealed and crystallized, a fine particle fraction that has been annealed and crystallized, and a weather-resistant protective layer formed on the surface of the coarse particle fraction and the fine particle fraction; The mass ratio of the coarse particle fraction to the fine particle fraction is 60:40 to 85:15, the volume-weighted average particle size of the coarse particle fraction is 8 μm to 30 μm, and the volume-weighted average particle size of the fine particle fraction is 0.10 μm to 1.2 μm. The weather-resistant protective layer is formed by dry pretreatment of hindered amine light stabilizer, ultraviolet absorber and nano zinc oxide, and the amount of weather-resistant protective layer is 0.8% to 2.5% based on the total dry basis mass of the coarse and fine particle fractions, the mass ratio of HALS to UVA is 0.5:1 to 8:6, and the mass fraction of nano zinc oxide is 10% to 60% based on the total mass of the weather-resistant protective layer; The additive undergoes surface hydrophobication treatment of fatty acids or fatty acid salts. The polyhydroxy fatty acid ester crystallinity of the additive is 40% to 70%, the main melting peak temperature during secondary heating is not lower than 150°C, the UVA surface retention rate is not lower than 82%, and the particle morphology retention rate at 80°C is above 90%.

8. A method for preparing the coating according to any one of claims 1 to 6, characterized in that, Includes the following steps: Pretreatment step: The bio-based hydrophobic multimodal crystalline particles, which have undergone annealing and crystallization and surface hydrophobication treatment with fatty acids or fatty acid salts, are mixed with a hindered amine light stabilizer, a UV absorber, and nano-zinc oxide at 40°C to 80°C for 3 to 20 minutes to obtain a particle additive that forms a weather-resistant protective layer on the surface. The mass ratio of the hindered amine light stabilizer to the UV absorber is 0.5:1 to 8:6, the mass fraction of nano-zinc oxide is 10% to 60% based on the total mass of the weather-resistant protective layer, and the amount of the weather-resistant protective layer is 0.8% to 2.5% based on the dry basis mass of the bio-based hydrophobic multimodal crystalline particles. Step 1: Mix water, dispersant and reflective component, and shear disperse at 1200 to 3000 r / min for 5 to 30 min. The fineness is measured to be ≤40 μm according to GB / T1724-2019 to obtain reflective slurry; Step 2: Add the reflective slurry obtained in Step 1 to the water-based film-forming matrix under stirring at 200 to 800 r / min, and mix for 5 to 15 min to obtain the film-forming matrix mixture slurry; Step 3: Add the heat insulation filler to the film-forming base material mixture obtained in Step 2 under stirring at 100 to 400 r / min, and mix for 5 to 15 min to obtain the heat insulation filler mixture base material; Step 4: Add the heat insulation filler mixture base slurry obtained in Step 3 to the particle additive obtained in the pretreatment step at a speed of 150 to 600 r / min, control the maximum material temperature of the system to be no higher than 50℃, and disperse for 10 to 40 min to obtain particle dispersion coating. Step 5: Add thickener, wetting agent, defoamer, leveling agent, preservative and film-forming aid to the particle dispersion coating obtained in Step 4, stir for 10 to 20 minutes, filter and package to obtain the finished coating product.

9. The method according to claim 8, characterized in that, The coarse particle fraction is annealed at 80°C for 1 to 8 hours, and the fine particle fraction is annealed at 45°C to 65°C for 0.5 to 4 hours. The finished coating obtained in step 5 has an application viscosity of 70 KU to 130 KU measured at 25°C according to GB / T9269-2009.

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