Water-based fluorocarbon colorful granite coating, preparation method and coating system of water-based fluorocarbon colorful granite coating

Abstract

The invention discloses a water-based fluorocarbon colorful granite coating, a preparation method and a coating system of the water-based fluorocarbon colorful granite coating. The coating is composed of a continuous phase and 20%-50% of colored particles. The continuous phase contains aqueous FEVE fluorocarbon emulsion, silica sol-acrylic acid composite emulsion, a surface modified attapulgite nanorod crystal material and the like; the colored particles take attapulgite colored sand calcined at a high temperature of more than 800 DEG C or an inorganic hybrid pigment thereof as a coloring component, and are matched with a modified synthetic silicate protective glue solution (with the dosage of 1%-3%). The thickness of a dry film of the surface coating is 250-500 microns, the film is formed at one time, and a surface coating is not needed. The VOC of the coating is smaller than or equal to 9 g / L, and delta Elt is obtained after QUV aging is conducted for 4000 h; the color particle has the advantages that the contact angle is up to 96-99 degrees, the stain resistance is less than or equal to 4.8%, and the color particle is stable to store. The invention has the advantages of super weather resistance, high color retention, strong self-cleaning property, real stone texture, simplicity and convenience in construction and the like, and is suitable for stone-like decoration of high-end building outer walls.

Description

Technical Field

[0001] This invention belongs to the field of building decoration material coating technology, and more specifically, it relates to a water-based fluorocarbon multicolor granite coating, its preparation method and coating system. Background Technology

[0002] With the growing adoption of green building and sustainable development concepts, water-based stone-like coatings have become an important alternative to natural stone due to their advantages such as low VOC emissions, safe construction, and realistic decorative effects. Currently, the mainstream products on the market mainly include two systems: "water-in-water" and "water-in-sand".

[0003] While water-in-water type multicolor coatings can achieve multicolor pattern effects, their coating film is relatively thin (the dry film thickness is usually less than 200 μm), lacking the three-dimensional texture and frosted feel of real stone, and the simulation degree is limited. Moreover, the color dots mostly rely on organic pigments for coloring, which are prone to fading and discoloration under long-term ultraviolet radiation, making it difficult to control the color difference between batches and affecting the overall decoration consistency.

[0004] "Water-based sand" coatings enhance texture by introducing colored sand, effectively mimicking the effect of flamed or lychee-textured granite. However, to achieve a full coverage without any bare spots, two coats are typically required, resulting in a coating weight of 1.0–1.8 kg / m², leading to low construction efficiency and high costs. Furthermore, existing systems often use pure acrylic emulsions, styrene-acrylic emulsions, or silicone-modified acrylic emulsions as film-forming substances. Their weather resistance, stain resistance, and corrosion resistance are insufficient to meet the stringent requirements of ultra-long-life (e.g., over 30 years) building exteriors. Conventional colorants are prone to precipitation and migration under high temperature, high humidity, acid rain, alkalinity, or freeze-thaw cycles, leading to coating chalking, cracking, or color distortion.

[0005] Although some technologies attempt to improve durability by adding a fluorocarbon topcoat, this not only increases the number of coats (often more than 5), but may also change the color saturation and gloss uniformity of the underlying layer, and significantly increase the overall cost. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a water-based fluorocarbon multicolor granite coating, its preparation method, and its coating system, thereby resolving issues such as poor weather resistance, easy fading, unstable color particles, insufficient simulation, and complex construction that are commonly found in existing water-based multicolor granite coatings.

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

[0008] On one hand, the present invention provides a water-based fluorocarbon multicolor granite coating, the coating comprising a continuous phase and colored particles dispersed in the continuous phase; wherein the colored particles account for 20% to 50% of the total mass of the coating; the colored particles refer to wet dispersed particles formed by coloring components and protective colloids, comprising an internal base paint, protective colloids and water.

[0009] The continuous phase comprises: aqueous FEVE fluorocarbon emulsion, organic-inorganic hybrid aqueous resin, surface-modified attapulgite nanorod crystal material, film-forming aid, defoamer, leveling agent, preservative and mildew inhibitor, and deionized water;

[0010] The colored particles are composed of a coloring component and a protective colloid. The coloring component is selected from attapulgite inorganic hybrid pigments or colored sand made by calcining the pigments at a high temperature of 800°C or above. The protective colloid is a modified synthetic silicate sol-type anionic aqueous rheology modifier.

[0011] Preferably, based on the total mass of the continuous phase, the waterborne FEVE fluorocarbon emulsion has a mass percentage of 15% to 40%, the organic-inorganic hybrid waterborne resin has a mass percentage of 5% to 20%, and the surface-modified attapulgite nanorod material has a mass percentage of 0.5% to 3%.

[0012] Preferably, based on the total mass of the colored particle slurry, the mass percentage of the modified synthetic silicate protective adhesive solution is 1% to 3%.

[0013] Preferably, the particle size of the colored particles is 0.5 mm to 3 mm.

[0014] Preferably, the organic-inorganic hybrid aqueous resin is a silica sol-acrylic composite emulsion.

[0015] On the other hand, the present invention provides a method for preparing the above-mentioned waterborne fluorocarbon multicolor granite coating, comprising the following steps:

[0016] S1: Preparation of colored particles: The coloring component is mixed with the protective adhesive, conveyed by gravity and sheared and filtered through a rotating PTFE filter plate to obtain colored particles with uniform particle size;

[0017] S2: Preparation of continuous phase: The aqueous FEVE fluorocarbon emulsion, organic-inorganic hybrid aqueous resin, surface-modified attapulgite nanorod crystal material, film-forming aid, defoamer, leveling agent, and preservative and mildew inhibitor are stirred and dispersed evenly in deionized water.

[0018] S3: Add the colored particles obtained in step S1 to the continuous phase obtained in step S2, and mix at low speed to obtain the coating.

[0019] Preferably, an aqueous film-forming resin (such as at least one of aqueous FEVE fluorocarbon emulsion or organic-inorganic hybrid aqueous resin) may be added in step S1 to enhance the cohesive strength and water resistance of the colored particles.

[0020] Preferably, the pore size of the rotating PTFE filter disc is 0.5 mm to 3 mm, which can precisely control the particle size distribution and avoid fusion or breakage.

[0021] Furthermore, the present invention provides a building exterior wall coating system, comprising, from bottom to top:

[0022] Primer: Water-based alkali-resistant sealing primer;

[0023] Intermediate coating: Water-based imitation stone intermediate paint;

[0024] Topcoat: Water-based fluorocarbon multicolor granite coating as described above.

[0025] Preferably, the thickness of the surface coating after drying is 250–500 μm.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] By integrating water-based FEVE fluorocarbon emulsion, organic-inorganic hybrid resin, surface-modified attapulgite nanomaterials, and high-temperature stable inorganic colored sand, this technology solves the core problems of traditional multi-color coatings, such as poor weather resistance, easy fading, insufficient texture, unstable color particles, and complex construction. It achieves a synergistic breakthrough in terms of ultra-weather resistance, high color retention, strong self-cleaning properties, a stone-like texture, and simplified construction. Simultaneously, the all-water-based formula meets low VOC environmental protection requirements, combining long-lasting protection with high decorative properties, significantly improving the overall performance and application value of architectural exterior stone-like coatings. Detailed Implementation

[0028] To enable those skilled in the art to clearly and completely implement this invention, the sources, preparation methods, and technical features of the key raw materials involved in the embodiments are described in detail below. Unless otherwise specified, all raw materials are industrial grade or prepared by conventional methods.

[0029] Aqueous FEVE fluorocarbon emulsion: This emulsion uses commercially available aqueous chlorotrifluoroethylene-vinyl ether copolymer (FEVE) with a solids content of 45±2%, a minimum film-forming temperature (MFFT) of 20–30℃, and a glass transition temperature (Tg) of approximately 25℃. This emulsion can be supplied by domestic suppliers with high-performance fluorocarbon emulsion production capabilities, eliminating the need for separate synthesis.

[0030] Organic-inorganic hybrid waterborne resin: The organic-inorganic hybrid waterborne resin of this invention is a silica sol-acrylic composite emulsion, which can be obtained by any of the following methods: (1) directly purchasing commercially available imitation stone coating special hybrid emulsion (such as a certain brand of "silicone-acrylic hybrid emulsion", solid content 35%, SiO2 content about 10%); (2) physically blending commercially available acidic silica sol (SiO2 content 20-30%, pH=8-9) with pure acrylic emulsion at a mass ratio of 1:2-1:4 and dispersing at high speed for 30 minutes. This resin has both the flexibility of organic polymers and the hardness and weather resistance of inorganic silicon, and has good compatibility with FEVE fluorocarbon emulsion.

[0031] Attapulgite-based inorganic weather-resistant pigment: This pigment is the core coloring material of this invention and is prepared by the following steps: Take 100 g of naturally purified attapulgite powder (particle size ≤10 μm, purity ≥90%), add an aqueous solution containing metal oxide precursors (such as Fe(NO3)3, Cr(NO3)3, TiOSO4, etc.), impregnate for 12 h, and dry at 80℃ to obtain a supported attapulgite inorganic hybrid pigment. This pigment does not contain organic dyes, has excellent thermal stability, and is suitable for subsequent high-temperature treatment.

[0032] High-temperature calcined colored sand: The above-mentioned attapulgite-based inorganic weather-resistant pigment is mixed evenly with quartz sand, completely coating the surface, and then placed in a muffle furnace and calcined at 850°C for 2 hours. After natural cooling, it is mechanically crushed and vibrated sieved to collect particles with a particle size of 0.5–3 mm, thus obtaining high-temperature calcined colored sand. This colored sand has stable color, is insoluble in water, resistant to acids and alkalis, resistant to organic solvents, and resistant to shear stirring, completely avoiding the problems of precipitation and migration during construction or use of traditional color pastes. Preferably, the coloring component of the colored particles of this invention can be selected from the above-mentioned uncalcined attapulgite inorganic hybrid pigment or its high-temperature calcined product, colored sand.

[0033] Surface-modified attapulgite nanorods: This material is a functional nano-additive in the continuous phase. The preparation method is as follows: 5 g of purified attapulgite nanorods (aspect ratio > 20, specific surface area ≥ 120 m² / g) are dispersed in 100 mL of anhydrous ethanol, and 1.5 g of perfluorodecyltriethoxysilane (PFDTES) is added. The mixture is refluxed at 70 °C for 6 h. After the reaction, the mixture is centrifuged and washed successively with ethanol and deionized water until neutral. It is then vacuum dried at 60 °C for 12 h to obtain superhydrophobic modified attapulgite nanopowder. In use, it is dispersed in water by high-speed shearing or ultrasonic assistance and directly added to the continuous phase.

[0034] Modified Synthetic Silicate Sol-Type Anionic Aqueous Rheology Modifier (Protective Gel): The protective gel used in this invention is not a common bentonite-based colloid, but rather a "specially modified synthetic silicate sol-grade anionic aqueous rheology modifier." Its preparation / selection method is as follows: Based on commercially available synthetic lithium magnesium silicate aqueous sol (8% solid content, pH=9.5), 0.5 wt% sodium dodecyl sulfate (SDS) is added as an anion regulator, and the pH is finely adjusted to 9.8–10.0 with ammonia. After stirring evenly, it is allowed to stand for 24 hours to mature, thus obtaining a special protective gel solution. This modification significantly improves its encapsulation stability of inorganic colored particles in high fluorocarbon content systems, effectively preventing particle fusion and deformation during storage. The 'protective gel dosage' mentioned herein refers to the mass of the modified protective gel solution, not its solid content.

[0035] Other additives and media: Film-forming aid: commercially available alcohol ester-12; Defoamer: commercially available mineral oil-based defoamer; Leveling agent: commercially available polyether-modified polysiloxane; Preservative and mildew inhibitor: commercially available isothiazolinone compound; Deionized water: laboratory-made, resistivity ≥1 MΩ·cm.

[0036] Example 1

[0037] S1 Color Particle Preparation: Weigh 100 g of attapulgite inorganic hybrid pigment (dry powder), add 10.2 g of the above-mentioned modified synthetic silicate protective colloid solution, then add deionized water, and mix evenly to obtain a total mass of 1000 g of color particle preparation slurry. The mass ratio of the protective colloid solution is approximately 10.2 / 1000 ≈ 1%.

[0038] The above slurry was gravity-fed and passed through a rotating PTFE filter disc with a pore size of 0.5 mm for shearing and granulation to obtain colored particles with a particle size of 0.5–0.8 mm. The resulting colored particle slurry had a solid content of approximately 10%, equivalent to a dry particle mass of 100 g.

[0039] S2 Continuous Phase Preparation (based on a total continuous phase mass of 100 g): 15 g aqueous FEVE fluorocarbon emulsion; 5 g organic-inorganic hybrid aqueous resin; 0.5 g surface-modified attapulgite nanorods; 1.0 g film-forming aid; 0.8 g defoamer, leveling agent, and preservative / mildew inhibitor; the remainder being deionized water, totaling 100 g. The mixture was stirred and dispersed at 800 rpm for 30 min to obtain a homogeneous continuous phase.

[0040] S3 Coating Preparation: Take 1000 g of the above-mentioned colored particle slurry, add 400 g of continuous phase, and stir at low speed (200 rpm, 10 min) to obtain a total mass of 1400 g of finished coating. The mass percentage of the colored particle slurry in the obtained coating is 100 / (100 + 400) = 20%.

[0041] Example 2

[0042] Preparation of S1 colored particles: Weigh 100 g of attapulgite colored sand calcined at 850℃, add 20.4 g of the above-mentioned modified synthetic silicate protective colloid solution, 10 g of aqueous FEVE fluorocarbon emulsion, and then add deionized water to obtain a total mass of 1000 g of colored particle slurry. The protective colloid accounts for 20.4 / 1000 = 2.04%. Granulate through a rotating PTFE filter disc with a pore size of 1.5 mm to obtain colored particles with a particle size of 1.2–2.0 mm.

[0043] S2 continuous phase preparation (total mass 100 g): aqueous FEVE fluorocarbon emulsion: 27.5 g; silica sol-acrylic composite emulsion: 12.5 g; surface-modified attapulgite nanorods: 1.5 g; total additives: 3.0 g; the remainder is deionized water, totaling 100 g.

[0044] S3 Coating Preparation: Take 1000 g of colored particle paste, add 185.7 g of continuous phase, and after mixing, the total mass is 1185.7 g. In the resulting coating, the mass ratio of colored particle paste is 100 / (100 + 185.7) ≈ 35%.

[0045] Example 3

[0046] S1 Color Particle Preparation: Weigh 100 g of dry powder containing attapulgite inorganic hybrid pigment and high-temperature calcined colored sand, add 30.9 g of the above-mentioned modified synthetic silicate protective colloid solution, 20 g of organic-inorganic hybrid waterborne resin, and then add deionized water to obtain a total mass of 1000 g of colored particle slurry. The protective colloid accounts for 30.9 / 1000 = 3.09%. Granulate through a rotating PTFE filter disc with a pore size of 3.0 mm to obtain colored particles with a particle size of 2.5–3.0 mm.

[0047] S2 continuous phase preparation (total mass 100 g): aqueous FEVE fluorocarbon emulsion: 40 g; silica sol-acrylic composite emulsion: 20 g; surface-modified attapulgite nanorod crystals: 3.0 g; total additives: 4.0 g; the remainder is deionized water, totaling 100 g.

[0048] S3 Coating Preparation: Take 1000 g of colored particle paste, add 100 g of continuous phase, and mix until the total mass is 1100 g. The mass ratio of colored particle paste in the resulting coating is 100 / (100 + 100) = 50%.

[0049] The components obtained in Examples 1-3 above were used to prepare test plates. The specific process is as follows:

[0050] Substrate treatment: Use asbestos-free fiber cement flat board (size 150 mm × 70 mm × 6 mm, conforming to JG / T24–2000); sand the surface with 240# sandpaper until smooth and remove dust; dry for 24 h in a standard environment (23±2℃, 50±5% RH).

[0051] Painting application:

[0052] Primer application: Apply one coat of water-based alkali-resistant sealing primer (commercially available general-purpose type) by roller or spray, using approximately 0.10 kg / m². The primer should evenly cover the substrate, without any missed spots or runs. It should be surface dry in about 2 hours at room temperature, and fully dry (25℃, ≥24 hours) before proceeding to the next step.

[0053] Intermediate Coating Application: Apply one coat of water-based stone-like intermediate coat (usually a thick putty-type paint containing graded quartz sand) by trowel, roller, or spray, with a thickness controlled at 0.8–1.2 mm. The intermediate coat not only provides good adhesion and smoothness but also imparts the main color tone and basic texture to the coating, simulating the rugged texture of natural granite. Allow to air dry for at least 24 hours after troweling or roller / spraying to ensure complete curing.

[0054] Topcoat application: The water-based fluorocarbon multicolor granite coatings prepared in Examples 1, 2, and 3 of this invention are thoroughly stirred and applied using air spraying. The spray gun nozzle diameter is 2.5–4.0 mm; the working pressure is 0.5–0.7 MPa; the spraying distance is 30–40 cm. One coat is applied using a cross-spraying method to ensure uniform distribution of colored particles, full patterns, and no exposed substrate. The dry film thickness of the topcoat is controlled within the range of 250–500 μm, and a single film formation is sufficient to create a realistic multicolor granite decorative effect.

[0055] Curing: After construction, allow to cure naturally for 7 days at room temperature (≥5℃) and in a well-ventilated environment, avoiding rain or heavy impacts during this period. Alternatively, bake at 50-80℃ for 2-3 hours until the coating is fully cured, at which point it will possess excellent weather resistance, self-cleaning properties, and long-term color retention.

[0056] In this method, a magnetic thickness gauge was used to randomly measure 5 points on each test plate, and the average value was taken. The measured thicknesses were: Example 1: 260 μm; Example 2: 350 μm; Example 3: 480 μm.

[0057] The following tests were conducted on the test panels after the above coating application was completed. The test items are shown in Table 1 below:

[0058] Table 1: Performance Test Items

[0059]

[0060] Specifically, in the above test items, the storage stability of the colored particles was evaluated as follows: 80 mL of the finished paint was placed into a 100 mL glass bottle, sealed, and placed in a 50℃ constant temperature incubator for 30 days. Observations were made weekly during this period, and samples were taken on the 30th day for microscopic morphology analysis and spray test panel verification. Pass: The colored particles are evenly distributed, slightly sink, but disperse rapidly after stirring; under a microscope, the colored particles are independent with sharp boundaries; the pattern is clear after spraying. Fail: The colored particles clump together and cannot disperse; under a microscope, they appear fused, stringy, or broken; color spots appear after spraying, and there is no three-dimensional effect.

[0061] The data obtained from Examples 1 to 3 are shown in Table 2 below:

[0062] Table 2: Performance Test Data

[0063]

[0064] As shown in Table 2, regarding superior weather resistance and color retention, the color difference ΔE of the three embodiments of this invention after 4000 hours of QUV-B accelerated aging was 1.4, 1.1, and 1.3, respectively, all far below the threshold perceptible to the naked eye (ΔE≈1.5). In contrast, commercially available ordinary water-based sand products reached ΔE of 3.8 after only 2000 hours of aging, exhibiting severe fading; even high-end commercially available products using a combination of "silicone-acrylic main material + fluorocarbon coating" still had a ΔE as high as 2.6 after 4000 hours, with yellowing and micro-cracks appearing in the coating layer. This indicates that this invention, through the synergistic effect of inorganic high-temperature calcined colored sand and water-based FEVE fluorocarbon emulsion, achieves weather resistance performance surpassing existing high-end composite systems without the need for any coating layer, demonstrating a breakthrough in technical effectiveness.

[0065] In terms of self-cleaning and anti-fouling capabilities, the coating of this invention boasts a water contact angle of 96°~99° and a stain resistance of only 3.2%–4.8%. In contrast, commercially available product A has a contact angle of only 72° and a stain rate as high as 26.5%; while product B shows slight improvement due to its coating (stain rate 12.3%), it is still far inferior to this invention. This difference stems directly from the synergistic effect of the surface-modified attapulgite nanorods introduced into the continuous phase of this invention, along with the fluorocarbon low surface energy film, forming a dense hydrophobic structure that makes it difficult for pollutants to adhere, allowing rainwater to wash away and self-clean the coating.

[0066] In terms of construction efficiency and material economy, the dry film thickness of the topcoat of this invention is 250–500 μm. Through the design of high-solids colored particles and efficient continuous phase, a single spraying can achieve full patterns and complete coverage; while commercially available product A requires two sprayings of the main material (dry film thickness up to 380 μm), and product B requires five processes. While ensuring excellent texture and durability, this invention reduces the amount of topcoat material used by about 30–40% compared to traditional water-based sand coatings, and eliminates the need for expensive fluorocarbon topcoats, significantly reducing overall costs.

[0067] In terms of environmental performance, the VOC content of this invention is 6–9 g / L, which is far below the limit of GB / T 38597–2020 "Low VOC Coatings" (≤50 g / L), fully meeting the requirements of green building certification; while the commercially available product A has 68 g / L, and product B has a VOC as high as 82 g / L due to the presence of fluorocarbon coating.

[0068] Crucially, the stability of the colored particles is paramount: even after 30 days of storage at 50°C, the colored particles of this invention remain intact and unfused, and can be evenly dispersed after stirring, resulting in clear sprayed patterns; while commercially available products generally exhibit particle adhesion and blurred edges, leading to "painted" failure. This result verifies the unique effectiveness of the modified synthetic silicate sol-type anionic protective colloid used in high-fluorocarbon, high-solids systems, solving the long-standing problem of storage stability in multicolor coatings.

[0069] Below, based on Example 2, we will further explain the innovations of this solution. The comparative example focuses on three key indicators: artificial accelerated aging (ΔE), stain resistance, and storage stability of colored particles.

[0070] Comparative Example 1

[0071] In Example 2, the high-temperature calcined attapulgite colored sand was replaced with an equal mass of commercially available organic color paste mixture (containing iron oxide red and carbon black paste), while the other components and processes remained unchanged.

[0072] Test results showed that Comparative Example 1 exhibited a color difference ΔE as high as 3.9 after 4000 hours of QUV-B accelerated aging, far exceeding the 1.1 of Example 2; its stain resistance deteriorated from 3.2% to 25.8%; and after 30 days of storage at 50°C, the edges of the colored particles became noticeably blurred and partially fused, resulting in a "bleached" appearance after spraying. This indicates that organic pigments are highly susceptible to degradation under UV and thermo-oxidative conditions, leading not only to severe fading but also to damage the interfacial stability of the colored particles due to their hydrophilicity and small molecule migration characteristics. In contrast, the high-temperature calcined inorganic colored sand used in this invention, with its metal oxides firmly dissolved in the attapulgite lattice, fundamentally eliminates fading and precipitation problems, making it crucial for achieving superior weather resistance and color durability.

[0073] Comparative Example 2

[0074] The modified synthetic silicate sol-type anionic protective gel used in Example 2 was replaced with an equal amount of ordinary sodium-based bentonite aqueous dispersion, while other conditions remained unchanged.

[0075] Experiments revealed that Comparative Example 2 exhibited particle adhesion after only 7 days of storage at 50℃, and completely agglomerated after 30 days, unable to be restored to a uniform state through stirring. The resulting coating lacked clear patterns, appearing only as mottled patches. Although its film-forming system was the same as Example 2, ordinary bentonite suffered severe charge shielding in high-fluorocarbon emulsion and electrolyte environments, failing to form an effective steric stabilizing layer. In contrast, the modified synthetic silicate protective colloid used in this invention, due to its nanosheet structure, high negative charge density, and compatibility modification with the fluorocarbon system, can construct a stable hydration barrier on the particle surface, effectively preventing fusion caused by van der Waals forces between particles. This difference demonstrates that the specialized protective colloid represents a technological breakthrough in achieving long-term storage stability of high-solids-content, large-particle-size colored particles.

[0076] Comparative Example 3

[0077] Based on Example 2, the surface-modified attapulgite nanorod crystal material was completely omitted, and the total amount of continuous phase was made up with an equal amount of deionized water.

[0078] The results showed that the water contact angle of the comparative sample decreased from 99° to 82°, the stain resistance increased from 3.2% to 18.6%, and ΔE increased to 1.8 after 4000 hours of aging. Microcracks also appeared in the flexibility test. This is because the absence of nanorods reduced the coating's density, increased micropores, and made it easier for contaminants to penetrate and adhere. Simultaneously, the lack of the nano-reinforcing network weakened the coating's cohesive strength and anti-aging ability. In contrast, this invention introduces perfluorosilane-modified attapulgite nanorods, which not only endow the coating with superhydrophobic properties but also utilize their one-dimensional rod-like structure to form physical cross-linking points in the continuous phase, significantly improving the coating's mechanical integrity and durability.

[0079] In summary, the comparative examples above respectively verify the irreplaceable technical value of the high-temperature calcined inorganic colored sand, the modified synthetic silicate protective colloid, and the surface-modified attapulgite nanorods in this invention. The absence of any one of these elements leads to a significant deterioration of key performance indicators, and may even render the product unusable. This fully demonstrates that this solution is not a simple replacement or combination of existing materials, but rather a novel technical system with synergistic effects, built upon a deep understanding of the failure mechanism of multi-color coatings and through the systematic integration of materials chemistry, interface engineering, and structural design.

[0080] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A water-based fluorocarbon multicolor granite coating, characterized in that, The coating comprises a continuous phase and colored particles dispersed in the continuous phase; wherein the colored particles account for 20% to 50% of the total mass of the coating. The continuous phase comprises: aqueous FEVE fluorocarbon emulsion, organic-inorganic hybrid aqueous resin, surface-modified attapulgite nanorod crystal material, film-forming aid, defoamer, leveling agent, preservative and mildew inhibitor, and deionized water; The colored particles are composed of a coloring component and a protective colloid. The coloring component is selected from attapulgite inorganic hybrid pigments or colored sand made by calcining the pigments at a high temperature of 800°C or above. The protective colloid is a modified synthetic silicate sol-type anionic aqueous rheology modifier.

2. The water-based fluorocarbon multicolor granite coating as described in claim 1, characterized in that: Based on the total mass of the continuous phase, the waterborne FEVE fluorocarbon emulsion has a mass percentage of 15% to 40%, the organic-inorganic hybrid waterborne resin has a mass percentage of 5% to 20%, and the surface-modified attapulgite nanorod material has a mass percentage of 0.5% to 3%.

3. The water-based fluorocarbon multicolor granite coating as described in claim 1, characterized in that: Based on the total mass of the colored particle slurry, the mass percentage of the modified synthetic silicate protective adhesive solution is 1% to 3%.

4. The water-based fluorocarbon multicolor granite coating as described in claim 1, characterized in that: The particle size of the colored particles is 0.5 mm to 3 mm.

5. The water-based fluorocarbon multicolor granite coating as described in claim 1, characterized in that: The organic-inorganic hybrid aqueous resin is a silica sol-acrylic composite emulsion.

6. A method for preparing a waterborne fluorocarbon multicolor granite coating as described in any one of claims 1 to 5, characterized in that, Includes the following steps: : S1: Preparation of colored particles: The coloring component is mixed with the protective adhesive, conveyed by gravity and sheared and filtered through a rotating PTFE filter disc to obtain colored particles with uniform particle size; S2: Preparation of continuous phase: The aqueous FEVE fluorocarbon emulsion, organic-inorganic hybrid aqueous resin, surface-modified attapulgite nanorod crystal material, film-forming aid, defoamer, leveling agent, and preservative and mildew inhibitor are stirred and dispersed evenly in deionized water. S3: Add the colored particles obtained in step S1 to the continuous phase obtained in step S2, and mix at low speed to obtain the coating.

7. The method for preparing a water-based fluorocarbon multicolor granite coating as described in claim 6, characterized in that: The aqueous film-forming resin mentioned in step S1 is at least one of aqueous FEVE fluorocarbon emulsion or organic-inorganic hybrid aqueous resin.

8. The method for preparing a water-based fluorocarbon multicolor granite coating as described in claim 6, characterized in that: The pore size of the rotating PTFE filter disc is 0.5 mm to 3 mm.

9. A building exterior wall coating system for water-based fluorocarbon multicolor granite coating as described in any one of claims 1 to 5, characterized in that, From bottom to top, they include: Primer: Water-based alkali-resistant sealing primer; Intermediate coating: Water-based imitation stone intermediate paint; Topcoat: Waterborne fluorocarbon multicolor granite coating as described in any one of claims 1–5.

10. The building exterior wall coating system as described in claim 9, characterized in that, The thickness of the surface coating after drying is 250–500 μm.

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