A wear-resistant and antifouling stone-like surface protective coating and a preparation method thereof

Abstract

The present application relates to the technical field of protective coating preparation, and particularly relates to a wear-resistant and stain-resistant stone-like surface protective coating and a preparation method thereof, which comprises the following steps: dispersing inorganic fillers in an oil-water two-phase system to form a Pickering emulsion, performing hydrophilic modification treatment and hydrophobic modification treatment on the inorganic filler hemispheres, and performing demulsification separation treatment to obtain modified fillers; determining whether the modified fillers are qualified based on the contact angle of the modified fillers; in response to the modified fillers being qualified, mixing the modified fillers with epoxy resin, and standing and aging to obtain a mixture, and determining whether the mixture meets the standard based on a migration coefficient; in response to the mixture meeting the standard, mixing and dispersing the mixture with pigments and additives, and performing vacuum degassing treatment to obtain a coating slurry, coating the coating slurry on a substrate surface for orientation treatment, determining a curing strategy based on a curing coefficient, and performing cooling treatment to obtain the stone-like surface protective coating. The present application improves the wear resistance and stain resistance of the protective coating.

Description

Technical Field

[0001] This invention relates to the field of protective coating preparation technology, and in particular to a wear-resistant and stain-resistant imitation stone surface protective coating and its preparation method. Background Technology

[0002] Stone-like coatings mimic the texture and color of natural stone by forming a composite film containing inorganic fillers and polymer resins on the surface of a substrate. They are widely used in decorative applications such as building exteriors, floors, and countertops. Existing stone-like coatings typically use inorganic fillers combined with epoxy or polyurethane resins, but these coatings generally suffer from the following technical problems in practical applications: The interfacial bonding strength between the filler and the resin is insufficient. In conventional stone-like coatings, the inorganic filler and resin only have physical adsorption or simple coupling agent treatment, resulting in limited interfacial bonding. Under repeated friction loads, micro-debonding easily occurs at the filler-resin interface, leading to filler particle peeling and a short wear life of the coating.

[0003] It is difficult to improve the antifouling performance and wear resistance of a coating surface in a coordinated manner. To improve antifouling performance, low surface energy substances are usually introduced to reduce the surface energy of the coating, but these additives will weaken the interfacial bonding between the filler and the resin. Conversely, increasing the filler content or using high-hardness fillers to improve wear resistance will lead to increased surface roughness and decreased antifouling performance. There is an inherent contradiction between the two.

[0004] The particle orientation is uncontrollable during coating preparation. The orientation behavior of modified fillers in liquid resin directly affects the enrichment of hydrophobic groups on the surface of the coating and the bonding density of the internal interface. However, existing processes lack quantitative characterization and control methods for orientation quality, resulting in poor batch-to-batch stability of coating performance.

[0005] The residual thermal stress generated during the curing process can easily lead to microcracks. The curing shrinkage of epoxy resin differs significantly from that of inorganic fillers in terms of their coefficient of thermal expansion. If the curing process is improper, thermal-chemical coupled residual stress will be generated at the interface, resulting in coating cracking or decreased adhesion.

[0006] Chinese Patent Application Publication No. CN118146721A discloses a wear-resistant and anti-fouling coating and its preparation method. The method involves mixing antimony tin oxide powder, nanoparticles, graphene, and activated carbon powder, adding a grinding medium, mixing thoroughly, separating the grinding medium, drying, and activating the mixture to obtain nano-activated powder. Polytitanate and the activated powder are added to a n-butyl ether solvent while stirring and dispersed to obtain a first dispersion. A perhydropolysilazane solution is mixed with the first dispersion, and then n-butyl ether and a leveling agent are added and dispersed to obtain a second dispersion. The substrate surface is activated and plasma-cleaned, then immersed in the second dispersion, uniformly pulled out, and allowed to stand to obtain a base coating. The base coating is then wet-dried and dry-dried to obtain the target wear-resistant and anti-fouling coating.

[0007] However, the aforementioned wear-resistant and anti-fouling coating and its preparation method have the following problems: 1. The antifouling performance of the coating relies entirely on the overall low surface energy provided by low surface energy components such as all-hydrogen polysilazane. The filler and resin only have physical embedding or simple physical mixing, lacking a chemical anchoring design between them, resulting in insufficient interfacial bonding strength. 2. Under frictional load, the filler is prone to debonding and peeling, resulting in an inherent contradiction between wear resistance and anti-fouling properties, making it difficult to simultaneously meet the dual application requirements of wear resistance and high anti-fouling. Summary of the Invention

[0008] Therefore, the present invention provides a wear-resistant and stain-resistant protective coating for imitation stone surfaces and its preparation method, in order to overcome the problems in the prior art where the wear resistance and stain resistance of imitation stone coatings are difficult to improve in a coordinated manner, the orientation of fillers is uncontrollable, and the curing thermal stress is prone to cracking.

[0009] To achieve the above objectives, the present invention provides a method for preparing a wear-resistant and stain-resistant protective coating for imitation stone surfaces, comprising: Inorganic fillers are dispersed in an oil-water two-phase system to form a Pickering emulsion. Based on the partitioning of the oil-water interface, the inorganic filler hemispheres facing the water phase are hydrophilic modified, and the inorganic filler hemispheres facing the oil phase are hydrophobic modified. Demulsification and separation are then performed to obtain the modified filler. The qualification of the modified packing is determined based on the first contact angle of the modified packing and the second and third contact angles of the two hemispheres of the modified packing. In response to the qualified modified filler, the modified filler is mixed with epoxy resin and allowed to stand for aging to obtain a mixture. The migration coefficient is determined based on the settling rate and polarity coefficient of the mixture to determine whether the mixture meets the standard. In response to the compliance of the mixture, the mixture is mixed and dispersed with pigments and additives, and vacuum degassing is performed to obtain a coating slurry. The coating slurry is then coated onto the surface of the substrate for orientation treatment. The curing coefficient is determined based on the curing exothermic peak width and peak temperature of the coating slurry. Based on the curing coefficient, a curing strategy is determined, and a cooling treatment is performed to obtain a protective coating for the imitation stone surface.

[0010] Furthermore, based on the fact that the first contact angle is greater than or equal to the first preset contact angle, the second contact angle is greater than or equal to the second preset contact angle, and the third contact angle is less than or equal to the third preset contact angle, the modified filler is determined to be qualified.

[0011] Furthermore, the process of obtaining the mixture includes: mixing qualified modified filler and epoxy resin at a mass ratio of 30-50:70-50, stirring at a speed of 300-500 rpm, stirring for 15-30 minutes, and allowing to stand for aging for 20-40 minutes.

[0012] Furthermore, based on the migration coefficient being greater than or equal to the preset migration coefficient, it is determined that the mixed materials meet the standards.

[0013] Furthermore, the migration coefficient is determined by adding the product of the weighting coefficient and the ratio of the settling rate to the product of the weighting coefficient and the polarity coefficient. Wherein, the settling rate ratio is the ratio of a preset settling rate to the settling rate; The polarity coefficient is determined by dividing the difference between the dielectric constant at the bottom 2 mm of the mixture and the dielectric constant at the liquid surface 2 mm above the mixture by the sum of the dielectric constants at the bottom 2 mm of the mixture and the dielectric constant at the liquid surface 2 mm above the mixture.

[0014] Furthermore, the orientation process includes: uniformly coating the coating slurry onto the substrate surface using a scraping method, with a wet film thickness of 1.5mm to 2.5mm; transferring the coated substrate to a constant temperature chamber, maintaining the temperature at 5℃ to 15℃ for 1h to 2h, and then allowing it to stand at room temperature of 25℃ for 10min.

[0015] Furthermore, based on the curing coefficient being greater than or equal to the first preset curing coefficient, the curing strategy is determined to be the first curing strategy; The curing coefficient is determined by multiplying the ratio of the preset curing exothermic peak width to the curing exothermic peak width by the ratio of the peak temperature to the preset peak temperature. The curing temperatures of the first curing strategy are 40℃, 85℃ and 120℃, and the curing holding times are 40min, 90min and 30min, respectively.

[0016] Furthermore, based on the fact that the curing coefficient is greater than or equal to the second preset curing coefficient and less than the first preset curing coefficient, the curing strategy is determined to be the second curing strategy; The curing temperatures of the second curing strategy are 40℃, 85℃ and 120℃, and the curing holding times are 70min, 120min and 60min, respectively.

[0017] Furthermore, based on the fact that the curing coefficient is less than the second preset curing coefficient, the curing strategy is determined to be the third curing strategy; The curing temperatures of the third curing strategy are 40℃, 85℃ and 120℃, and the curing holding times are 100min, 150min and 90min, respectively.

[0018] On the other hand, the present invention also provides a wear-resistant and stain-resistant imitation stone surface protective coating, wherein the imitation stone surface protective coating is composed of the following raw materials in parts by weight: 30-50 parts modified filler, 50-70 parts epoxy resin, 5-15 parts pigment, 0.3-0.8 parts leveling agent, and 0.2-0.5 parts defoamer; The modified filler is an inorganic filler that has undergone hydrophilic and hydrophobic modification treatment at the interface of Pickering emulsion, and the inorganic filler is one or more of quartz sand, calcium carbonate, and silicon dioxide. The epoxy resin is E-51 bisphenol A type epoxy resin; The pigment is one or more of iron oxide red, iron oxide yellow, iron oxide black, and titanium dioxide; The leveling agent is BYK-331; The defoamer is BYK-054.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention modifies the two hemispheres of the inorganic filler by hydrophilic modification and hydrophobic modification respectively through Pickering emulsion interface partitioning, so that the same particle simultaneously possesses active sites covalently bonded to epoxy resin and antifouling groups that impart low surface energy to the surface, thus solving the problem of difficulty in achieving both wear resistance and antifouling. By comparing the contact angle with the preset contact angle, the quality of the modified filler is ensured, providing a structural basis for orientation treatment. The migration coefficient is determined based on the sedimentation rate and polarity coefficient, quantifying the orientation dynamics and order of particles in the resin. Combined with the orientation treatment, the hydrophobic hemispheres are further oriented and enriched on the coating surface, and the hydrophilic hemispheres are anchored inside the resin, improving the surface hydrophobicity and interfacial bonding strength. Furthermore, the curing coefficient is determined based on the curing exothermic peak width and peak temperature to determine different curing strategies, effectively eliminating interfacial thermal residual stress, inhibiting the initiation of microcracks, and improving the wear resistance of the protective coating.

[0020] Furthermore, this invention quantitatively determines the quality of modified fillers using a first contact angle, a second contact angle, and a third contact angle. The first contact angle characterizes the overall average wettability of the filler, the second contact angle reflects the grafting density of low surface energy groups in the hydrophobic hemispheres, and the third contact angle characterizes the retention degree of active sites in the hydrophilic hemispheres. This results in clear polar partitions on the filler surface. The hydrophilic hemispheres retain sufficient amino or hydroxyl groups, enabling covalent bonding with epoxy resin to form a high-strength interfacial bonding layer. Under frictional loads, this layer preferentially absorbs stress and inhibits filler peeling, thereby improving wear resistance. The fluorocarbon or alkyl chains grafted onto the hydrophobic hemispheres impart extremely low surface energy to the coating, making it difficult for stains such as ink and soy sauce to wet and spread, thus achieving anti-fouling. This upgrades the qualitative observation of the chemical state of the modified filler surface to quantitative control, ensuring the integrity and batch stability of the modified filler. It resolves the material contradiction between the need for high interfacial bonding for wear resistance and the need for low surface energy for anti-fouling, laying a structural foundation for the coating to simultaneously achieve excellent wear resistance and anti-fouling properties.

[0021] Furthermore, this invention constructs a migration coefficient using sedimentation rate and polarity coefficient, thereby achieving a quantitative characterization of the orientation behavior of modified fillers in epoxy resin. The sedimentation rate reflects the dispersion state and mobility of the modified filler in the resin. A moderate sedimentation rate ensures that the particles have sufficient time in the liquid resin to complete the dynamic process from random distribution to ordered flipping, avoiding the situation where the particles settle before orientation due to excessively fast sedimentation or insufficient orientation motive force due to excessively slow sedimentation. The polarity coefficient quantifies the dielectric constant gradient of the resin system from the top air interface to the bottom substrate interface. The dielectric constant gradient is the fundamental thermodynamic force driving the hydrophilic hemispheres toward the highly polar substrate and the hydrophobic hemispheres toward the low polar air interface. Based on the migration coefficient, the dynamic conditions and thermodynamic driving force of particle orientation are evaluated, ensuring the increased enrichment of hydrophobic groups on the coating surface and sufficient interfacial covalent bond density after orientation treatment, thus guaranteeing the wear resistance and antifouling properties of the coating and achieving pre-quantitative control of the coating's microstructure.

[0022] Furthermore, this invention employs an orientation treatment, placing the coated slurry in an environment of 5℃~15℃. This significantly increases the viscosity of the epoxy resin without reaching the gel point, suppressing the Brownian motion of the modified filler particles. Simultaneously, the polarity difference between the hydrophilic and hydrophobic hemispheres drives the directional migration of the particles, ensuring that the hydrophilic hemispheres are stably oriented towards the substrate and the hydrophobic hemispheres towards the air interface. This enhances the orientational order of the particles, ensuring the enrichment of hydrophobic groups on the coating surface and the uniform distribution of interfacial bonding density. The curing coefficient is calculated based on the curing exothermic peak width and peak temperature of the coating slurry, and a curing strategy is determined accordingly. A narrow curing exothermic peak width indicates uniform filler distribution, allowing for sufficient cross-linking with a standard curing time. A broad exothermic peak indicates poor system uniformity, necessitating an extended post-curing holding time to ensure complete resin reaction and full release of interfacial residual thermal stress, preventing microcrack initiation. This achieves both modified filler orientation and curing stress elimination, ensuring the coating possesses both wear resistance and anti-fouling properties. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating the steps of preparing a wear-resistant and stain-resistant protective coating for imitation stone surfaces according to an embodiment of the present invention. Figure 2 This is a logic diagram for determining whether the modified filler is qualified in an embodiment of the present invention; Figure 3 This is a logic diagram illustrating whether the mixture meets the standards in an embodiment of the present invention. Figure 4 The logical decision diagram for determining the curing strategy in an embodiment of the present invention is shown. Detailed Implementation

[0024] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0025] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0026] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0027] Please see Figure 1The diagram shown is a flowchart illustrating the steps of preparing a wear-resistant and stain-resistant protective coating for a stone-like surface according to an embodiment of the present invention.

[0028] The method for preparing a wear-resistant and stain-resistant protective coating for imitation stone surfaces according to embodiments of the present invention includes: Step S1: Disperse the inorganic filler in an oil-water two-phase system to form a Pickering emulsion. Based on the partitioning of the oil-water interface, perform hydrophilic modification on the inorganic filler hemispheres facing the water phase and hydrophobic modification on the inorganic filler hemispheres facing the oil phase, and perform demulsification separation to obtain the modified filler. Step S2: Determine whether the modified filler is qualified based on the first contact angle of the modified filler and the second and third contact angles of the two hemispheres of the modified filler. Step S3: In response to the qualified modified filler, the modified filler is mixed with epoxy resin and allowed to stand for aging to obtain a mixture. The migration coefficient is determined based on the settling rate and polarity coefficient of the mixture to determine whether the mixture meets the standard. Step S4: In response to the mixture meeting the standard, the mixture is mixed and dispersed with pigments and additives, and vacuum degassing is performed to obtain a coating slurry. The coating slurry is then coated onto the surface of the substrate for orientation treatment. The curing coefficient is determined based on the curing exothermic peak width and peak temperature of the coating slurry. Step S5: Determine the curing strategy based on the curing coefficient and perform cooling treatment to obtain a protective coating for the imitation stone surface.

[0029] Specifically, this invention modifies the two hemispheres of the inorganic filler by hydrophilic and hydrophobic modification through Pickering emulsion interface partitioning. This allows the same particle to simultaneously possess active sites that covalently bond with epoxy resin and antifouling groups that impart low surface energy to the surface, solving the problem of the difficulty in achieving both wear resistance and antifouling. By comparing the contact angle with the preset contact angle, the quality of the modified filler is ensured, providing a structural basis for orientation treatment. The migration coefficient is determined based on the sedimentation rate and polarity coefficient, quantifying the orientation dynamics and orderliness of the particles in the resin. Combined with orientation treatment, the hydrophobic hemispheres are further oriented and enriched on the coating surface, while the hydrophilic hemispheres are anchored inside the resin, improving surface hydrophobicity and interfacial bonding strength. Furthermore, the curing coefficient is determined based on the curing exothermic peak width and peak temperature to determine different curing strategies, effectively eliminating interfacial thermal residual stress, inhibiting microcrack initiation, and improving the wear resistance of the protective coating.

[0030] Specifically, the process of forming a Pickering emulsion includes: mixing inorganic filler with deionized water at a solid-liquid ratio of 1:2 to 1:4, ultrasonically dispersing for 15 to 30 minutes to obtain an aqueous suspension, heating paraffin to 65°C to 70°C to completely melt it, adding it to the aqueous suspension at an oil-water volume ratio of 1:2 to 1:3, and emulsifying it at 8000 rpm to 12000 rpm for 5 to 10 minutes using a homogenizer to form a Pickering emulsion. It can be understood that during the emulsification process, the inorganic filler particles spontaneously adsorb to the oil-water interface, with one half of the inorganic filler particles facing the oil phase and the other half facing the aqueous phase.

[0031] Specifically, the hydrophilic modification process includes: adding γ-aminopropyltriethoxysilane (KH-550) to the aqueous phase at a dosage of 0.3% to 0.8% of the inorganic filler mass, at a reaction temperature of 60 to 70°C, at a reaction time of 1 to 2 hours, and at a stirring speed of 200 to 400 rpm. It can be understood that KH-550 hydrolyzes in the aqueous phase to generate silanol groups (Si-OH), which undergo a condensation reaction with the surface hydroxyl groups of the inorganic filler facing the aqueous phase hemisphere to form Si-O-Si covalent bonds, thus grafting amino groups onto the hemisphere surface.

[0032] Specifically, the hydrophobic modification process includes: adding a hydrophobic silane coupling agent to the oil phase, with an amount of 0.5% to 1.2% of the inorganic filler mass, a reaction temperature of 60 to 70°C, a reaction time of 1 to 2 hours, and a stirring speed of 200 to 400 rpm. It can be understood that in the oil phase, the hydrophobic silane undergoes a condensation reaction with the surface hydroxyl groups of the filler facing the oil phase hemisphere, grafting low surface energy groups.

[0033] In this embodiment of the invention, the hydrophobic silane coupling agent is one or more of heptadecafluorodecyltrimethoxysilane (FDTS), tridecafluorooctyltriethoxysilane, hexamethyldisilazane (HMDS), or octyltriethoxysilane.

[0034] Specifically, the demulsification and separation process includes: cooling the emulsion to room temperature, adding anhydrous ethanol or sodium chloride solution to demulsify, stirring for 10 to 20 minutes, and then separating the solid and liquid. The precipitate is washed twice with anhydrous ethanol and three times with deionized water. After each washing, the precipitate is centrifuged at 4000 to 6000 rpm for 10 minutes. The washed precipitate is then vacuum dried at 80°C for 4 hours to obtain the modified filler.

[0035] Please see Figure 2 As shown, it is a logic diagram for determining whether the modified filler is qualified according to an embodiment of the present invention.

[0036] Specifically, the qualification of the modified filler is determined based on the first contact angle of the modified filler and the second and third contact angles of the two hemispheres of the modified filler. If the first contact angle is greater than or equal to the first preset contact angle, the second contact angle is greater than or equal to the second preset contact angle, and the third contact angle is less than or equal to the third preset contact angle, then the modified filler is deemed qualified. If the first contact angle is less than the first preset contact angle, or the second contact angle is less than the second preset contact angle, or the third contact angle is greater than the third preset contact angle, then the modified filler is determined to be unqualified.

[0037] In this embodiment of the invention, the process of obtaining the first contact angle includes taking 0.5g of modified filler, pressing it into a disc with a diameter of 13mm under a pressure of 20MPa, adding 2μL of deionized water using a contact angle measuring instrument, measuring the static contact angle, and recording it as the first contact angle.

[0038] In this embodiment of the invention, the process of obtaining the second contact angle includes: uniformly spreading a single layer of modified filler on a double-sided adhesive tape; using a micro-area contact angle measuring instrument, adding 2 μL of deionized water droplets to the side of a single modified filler particle facing upwards, which faces the oil phase in step S1; measuring the contact angle, and recording it as the second contact angle.

[0039] In this embodiment of the invention, the process of obtaining the third contact angle includes: after measuring the first contact angle, placing the disc in an oxygen plasma cleaner and treating it for 10 seconds at a power of 50W and an oxygen flow rate of 20sccm to remove the hydrophobic groups of the monolayer on the disc surface; after treatment, re-measuring the contact angle and recording it as the third contact angle. Since the plasma treatment only etches the outermost layer of the surface (2nm to 5nm), while the modified filler inside that is not etched still retains the chemical properties of the hydrophilic hemisphere, the contact angle after treatment can be approximately equivalent to the contact angle of the hydrophilic hemisphere.

[0040] In this embodiment of the invention, the first preset contact angle is preferably 90°, the second preset contact angle is preferably 120°, and the third preset contact angle is preferably 60°. The values ​​are determined based on the following: selecting quartz sand filler from the same batch with D50=55μm, and preparing KH-550 grafting densities of 0.3, 0.5, 0.8, 1.0, and 1.2 grafts / nm respectively. 2 The grafting densities with FDTS were 0.2, 0.5, 0.8, 1.0, and 1.5 grafts / nm. 2The modified material was tested, and the three contact angles of each batch of particles were measured. The coatings were prepared and the Taber abrasion and water contact angle were tested. The experimental results showed that when the first contact angle was <90°, the overall hydrophobicity of the coating was insufficient and the water contact angle was <100°. When the second contact angle was <120°, the coverage of low surface energy groups on the coating surface was insufficient, and ink stains were easy to remain. When the third contact angle was >60°, there were too few bonding sites between the hydrophilic hemisphere and the epoxy resin, the interfacial bonding strength decreased, and the abrasion was >35mg / 100r. However, the above values ​​are not limited to these values, and those skilled in the art can adjust the values ​​according to actual needs.

[0041] Specifically, in response to the defective modified filler, the silane coupling agent in the next batch of modified material is adjusted. Based on the fact that the first contact angle is less than the first preset contact angle, it is determined that the amount of hydrophobic silane coupling agent and the amount of hydrophilic silane coupling agent should be increased by 0.1% to 0.2% respectively. Based on the fact that the second contact angle is less than the second preset contact angle, it is determined that the amount of hydrophobic silane coupling agent should be increased by 0.1% to 0.2%, and the reaction time should be extended by 15 to 30 minutes. Based on the fact that the third contact angle is greater than the third preset contact angle, it is determined that the amount of hydrophilic silane coupling agent should be reduced by 0.1% to 0.2%, and the reaction time should be reduced by 15 to 30 minutes.

[0042] In this embodiment of the invention, after each adjustment, the modified filler is re-prepared and three sets of contact angles are measured. If the contact angles after adjustment all meet the preset threshold, the batch is deemed qualified and the adjustment is stopped. If one or more contact angles still do not meet the preset threshold after three consecutive adjustments, the batch of inorganic filler is deemed unqualified and discarded.

[0043] Specifically, this invention quantitatively determines the quality of modified fillers using a first contact angle, a second contact angle, and a third contact angle. The first contact angle characterizes the overall average wettability of the filler, the second contact angle reflects the grafting density of low surface energy groups on the hydrophobic hemispheres, and the third contact angle characterizes the retention degree of active sites on the hydrophilic hemispheres. This results in clear polar partitions on the filler surface. The hydrophilic hemispheres retain sufficient amino or hydroxyl groups, enabling covalent bonding with epoxy resin to form a high-strength interfacial bonding layer. Under frictional loads, this layer preferentially absorbs stress and inhibits filler peeling, thereby improving wear resistance. The fluorocarbon or alkyl chains grafted onto the hydrophobic hemispheres impart extremely low surface energy to the coating, making it difficult for stains such as ink and soy sauce to wet and spread, achieving anti-fouling. This upgrades the qualitative observation of the chemical state of the modified filler surface to quantitative control, ensuring the integrity and batch stability of the modified filler. It resolves the material contradiction between the need for high interfacial bonding for wear resistance and the need for low surface energy for anti-fouling, laying a structural foundation for coatings to simultaneously achieve excellent wear resistance and anti-fouling properties.

[0044] Specifically, the process of obtaining the mixture includes: mixing qualified modified filler and epoxy resin at a mass ratio of 30-50:70-50, using a planetary stirrer at a stirring speed of 300-500 rpm for 15-30 minutes, and then allowing it to stand for aging for 20-40 minutes.

[0045] In this embodiment of the invention, the epoxy resin is E-51 bisphenol A type epoxy resin.

[0046] In this embodiment of the invention, during the static aging process, the epoxy resin remains in a low-viscosity liquid state, with a viscosity of 8000 mPa·s to 12000 mPa·s at 25°C. The mixture begins to undergo initial orientation migration under the drive of gravity settling and polar gradient. It can be understood that the hydrophilic hemispheres contain hydroxyl / amino groups, which strongly interact with the polar ether bonds and hydroxyl groups in the epoxy resin, thus tending to align towards the resin body and substrate. The hydrophobic hemispheres are grafted with low surface energy groups and tend to align towards the air interface. A static aging time of 20 to 40 minutes allows most of the particles in the mixture to complete the initial orientation, while avoiding excessively long aging times that could lead to resin gelation, thus preserving a sufficient flow window for the orientation process.

[0047] Please see Figure 3 As shown, it is a logic diagram for determining whether the mixture meets the standards in an embodiment of the present invention.

[0048] Specifically, the migration coefficient is determined based on the settling rate and polarity coefficient of the mixture to determine whether the mixture meets the standard; If the migration coefficient is greater than or equal to the preset migration coefficient, the mixture is deemed to meet the standard. If the migration coefficient is less than the preset migration coefficient, the mixture is determined to be substandard.

[0049] In this embodiment of the invention, the process of obtaining the sedimentation rate includes injecting the mixture into a glass colorimetric tube with an inner diameter of 20 mm, the top liquid level of the mixture being 100 mm, placing it in a constant temperature environment of 25°C, recording the sedimentation interface height every 5 minutes for a duration of 30 minutes, and obtaining the sedimentation rate by linear fitting with time as the abscissa and sedimentation distance as the ordinate.

[0050] In this embodiment of the invention, the process of obtaining the polarity coefficient includes using a dielectric constant probe with a frequency of 1 kHz to measure the dielectric constant ε1 at 2 mm below the top liquid surface of the mixture and the dielectric constant ε2 at 2 mm above the bottom of the mixture, and determining them using the following formula:

[0051] Where P represents the polarity coefficient, with a value ranging from -1 to 1. It can be understood that a positive polarity coefficient indicates the dielectric constant of the bottom (near the substrate) of the mixture. The dielectric constant is greater than that of the top (near the air side). There exists a decreasing polarity gradient from the substrate to the air interface. This decreasing polarity gradient is the core thermodynamic driving force for the directional migration of modified filler particles in liquid epoxy resin. The hydrophilic hemispheres of the modified filler, containing polar groups such as hydroxyl or amino groups, thermodynamically tend to face the high polarity region (substrate direction and resin body), while the hydrophobic hemispheres, grafted with low surface energy fluorocarbon chains or alkyl chains, tend to face the low polarity region (coating surface / air interface). The strength of the driving force can be quantified by the polarity coefficient, ensuring that during the orientation process, the particles can overcome Brownian motion and viscous resistance of the system, completing the orderly arrangement from random distribution to "hydrophilic hemispheres facing down and hydrophobic hemispheres facing up". This is a prerequisite for achieving high hydrophobicity on the coating surface and high interfacial bonding strength inside.

[0052] In this embodiment of the invention, the migration coefficient is determined by the following formula:

[0053] Wherein, k1 and k2 represent weighting coefficients. Through orthogonal experiments, k1 was determined to be 0.5 and k2 to be 0.5. v0 represents the settling rate, P represents the polarity coefficient, and v1 represents the preset settling rate, which is 0.05 mm / min. The basis for this value is: mixtures with settling rates of 0.03, 0.04, 0.05, 0.06, 0.07, and 0.08 mm / min were prepared and the coating performance was tested. The results showed that when the settling rate was between 0.04 and 0.06 mm / min, the particle orientation degree was ≥85%, the water contact angle of the coating was ≥112°, and the abrasion loss was ≤25 mg / 100 r.

[0054] Understandably, the settling rate reflects the dispersion state and mobility of the particles in the resin. An excessively high rate indicates particle agglomeration or low resin viscosity, preventing the particles from rotating in an orderly manner. An excessively low rate indicates insufficient orientation motive force. The polarity coefficient characterizes the dielectric constant gradient of the resin system from top to bottom and is the fundamental thermodynamic force driving the hydrophilic hemispheres toward the substrate and the hydrophobic hemispheres toward the air interface. By determining the migration coefficient, both the kinetic conditions of particle orientation and the thermodynamic driving force are quantified, indicating that the particles can not only rotate and orient themselves fully but also have a sufficient gradient to lock the orientation direction, thereby ensuring that the coating's wear resistance and antifouling performance meet the standards.

[0055] In this embodiment of the invention, the preset migration coefficient ranges from 0.85 to 0.95, preferably 0.90. The value is determined by preparing mixtures of modified filler and epoxy resin in ratios of 30:70, 40:60, and 50:50, measuring the settling rate and polarity coefficient of each batch, calculating the migration coefficient, and preparing corresponding coatings to test the orientation degree and coating performance. The experimental results show that when the migration coefficient is <0.85, the orientation degree is less than 70%, the coating water contact angle is <105°, and the abrasion loss is >30mg / 100r; when the migration coefficient is between 0.85 and 0.90, the orientation degree is 70% to 80%; and when the migration coefficient is ≥0.90, the orientation degree is ≥85%, the coating water contact angle is ≥112°, and the abrasion loss is ≤25mg / 100r. However, the above values ​​are not limited to these values, and those skilled in the art can adjust the values ​​according to actual needs.

[0056] Specifically, in response to substandard mixtures, propylene glycol methyl ether, a polarity modifier, is added at a rate of 1% to 3% of the resin mass. After addition, the mixture is allowed to stand for 10 minutes and the settling rate and polarity coefficient are re-measured.

[0057] It is understandable that extending the static aging time allows the particles to complete the turning and settling more fully in the gravitational field, but too long a time may lead to excessive cross-linking of the resin or secondary agglomeration of the particles. The addition of polarity regulators enhances the polarity gradient of the system, causing the hydrophilic hemispheres to face the substrate more strongly and the hydrophobic hemispheres to face the air interface, thereby obtaining a higher degree of orientation order in subsequent orientation treatment.

[0058] Specifically, this invention constructs a migration coefficient using sedimentation rate and polarity coefficient, thereby achieving a quantitative characterization of the orientation behavior of modified fillers in epoxy resin. The sedimentation rate reflects the dispersion state and mobility of the modified filler in the resin. A moderate sedimentation rate ensures that the particles have sufficient time in the liquid resin to complete the dynamic process from random distribution to ordered flipping, avoiding the situation where the particles settle before orientation due to excessively fast sedimentation or insufficient orientation motive force due to excessively slow sedimentation. The polarity coefficient quantifies the dielectric constant gradient of the resin system from the top air interface to the bottom substrate interface. The dielectric constant gradient is the fundamental thermodynamic force driving the hydrophilic hemispheres toward the highly polar substrate and the hydrophobic hemispheres toward the low polar air interface. Based on the migration coefficient, the dynamic conditions and thermodynamic driving force of particle orientation are evaluated, ensuring the increased enrichment of hydrophobic groups on the coating surface and sufficient interfacial covalent bond density after orientation treatment, thus guaranteeing the wear resistance and antifouling properties of the coating and achieving pre-quantitative control of the coating's microstructure.

[0059] Specifically, the process of obtaining the coating slurry includes: adding pigment, leveling agent and defoamer to the qualified mixture, dispersing it in a disperser at 800 rpm to 1200 rpm for 15 min to 25 min, then transferring it to a vacuum degassing machine and degassing it at a vacuum degree of -0.09 to -0.095 MPa for 30 min to 45 min to obtain the coating slurry.

[0060] In this embodiment of the invention, the pigment is one or more of iron oxide red, iron oxide yellow, iron oxide black, and titanium dioxide, and the amount used is 5% to 15% of the resin mass; the leveling agent is BYK-331, and the amount used is 0.3% to 0.8% of the resin mass; the defoamer is BYK-054, and the amount used is 0.2% to 0.5% of the resin mass.

[0061] Specifically, the orientation process includes: uniformly coating the substrate surface with the coating slurry using a scraping method, with a wet film thickness of 1.5mm to 2.5mm; transferring the coated substrate to a constant temperature chamber, maintaining the temperature at 5℃ to 15℃ for 1h to 2h, and then letting it stand at room temperature of 25℃ for 10min.

[0062] In this embodiment of the invention, the substrate is either artificial stone or ceramic tile.

[0063] Understandably, the viscosity of epoxy resin increases significantly in low-temperature environments of 5℃ to 15℃. The viscosity is 8000-12000 mPa·s at 25℃ and can rise to over 50000 mPa·s at 5℃, but it does not reach the gel point. The Brownian motion of the particles is effectively suppressed. Due to the polarity difference between the hydrophilic and hydrophobic hemispheres, the particles can still undergo directional migration driven by the polarity gradient. The low-temperature environment reduces the disturbance of thermal motion on orientation, making it easier for the particles to stabilize in the orientation state with the lowest energy. The hydrophilic hemispheres face the high polarity region inside the substrate / resin, and the hydrophobic hemispheres face the low polarity region on the coating surface / air interface. After standing for 1-2 hours for orientation, the degree of orientation can reach over 85%. Then, it is left to stand at room temperature for 10 minutes to allow the resin temperature to rise slowly, avoiding thermal stress caused by excessive temperature difference during subsequent curing.

[0064] Please see Figure 4 As shown, it is a logic judgment diagram for determining the curing strategy in an embodiment of the present invention.

[0065] The curing coefficient is determined based on the curing exothermic peak width and peak temperature of the coating slurry to determine the curing strategy, and then cooled to obtain a protective coating for the imitation stone surface. If the curing coefficient is greater than or equal to the first preset curing coefficient, the curing strategy is determined to be the first curing strategy; If the curing coefficient is greater than or equal to the second preset curing coefficient and less than the first preset curing coefficient, then the curing strategy is determined to be the second curing strategy. If the curing coefficient is less than the second preset curing coefficient, then the curing strategy is determined to be the third curing strategy.

[0066] In this embodiment of the invention, the process of obtaining the curing exothermic peak width and peak temperature includes taking 5mg to 10mg of coating slurry, using a differential scanning calorimeter (DSC), heating from 25℃ to 180℃ at a heating rate of 2℃ / min, recording the curing exothermic curve, and extracting the curing exothermic peak width and peak temperature from the curve. The curing exothermic peak width is the half-width at half-maximum of the exothermic peak, the width of the temperature range corresponding to 50% of the peak height, and the peak temperature is the temperature corresponding to the highest point of the exothermic peak.

[0067] In this embodiment of the invention, the first preset curing coefficient is preferably 1.02, and the second preset curing coefficient is preferably 0.92. The values ​​are determined as follows: Using an E-51 bisphenol A epoxy resin system, 15 groups of coating slurry samples with different filler dispersion uniformity levels were prepared. The curing exothermic peak width T1 and peak temperature T2 of each group were measured, and the curing coefficient K was calculated. Simultaneously, the abrasion resistance (Taber wear) and adhesion of the coatings prepared from each group of samples were tested. The test results were correlated with the curing coefficient. The experimental results show that when K ≥ 1.02, the coating abrasion ≤ 25 mg / 100 r, and the adhesion ≥ 9.0 N / mm. 2 When 0.92 ≤ K < 1.02, the coating abrasion loss is between 25 and 35 mg / 100 r, and the adhesion is between 8.0 and 9.0 N / mm. 2 Between; when K < 0.92, the coating abrasion loss is > 35 mg / 100 r, and the adhesion is < 8.0 N / mm. 2 However, the above values ​​are not limited to these, and those skilled in the art can adjust the values ​​according to actual needs.

[0068] In this embodiment of the invention, the curing coefficient is determined by the following formula:

[0069] Where T1 represents the curing exothermic peak width, T0 represents the preset curing exothermic peak width (valued at 45℃), T2 represents the peak temperature, and T3 represents the preset peak temperature (valued at 130℃). 45℃ is the average characteristic peak width measured by multiple DSC isothermal curing experiments of E-51 bisphenol A epoxy resin under a reference state with uniform filler dispersion and good system homogeneity; 130℃ is the characteristic peak temperature under this reference state.

[0070] In this embodiment of the invention, the first curing strategy is to use curing temperatures of 40°C, 85°C and 120°C, and curing holding times of 40 min, 90 min and 30 min, respectively.

[0071] In this embodiment of the invention, the second curing strategy is as follows: the curing temperatures are 40°C, 85°C and 120°C, and the curing holding times are 70 min, 120 min and 60 min, respectively.

[0072] In this embodiment of the invention, the third curing strategy is as follows: the curing temperatures are 40℃, 85℃ and 120℃, and the curing holding times are 100min, 150min and 90min, respectively.

[0073] In this embodiment of the invention, the heating rate is 2℃ / min, and the temperature transitions naturally between each temperature without the need for cooling. After curing, the furnace is naturally cooled to room temperature.

[0074] In this embodiment of the invention, the relationship between the curing coefficient K and the holding time of each temperature segment is determined based on the following kinetic mechanism: the curing reaction of epoxy resin follows the Arrhenius equation, the reaction rate constant k1=A·exp(-Ea / RT), where Ea represents the apparent activation energy, and the curing exothermic peak width T1 reflects the curing reaction distribution characteristics of the resin system in the coating slurry. The wider the curing exothermic peak width, the worse the uniformity of filler dispersion and the more dispersed the distribution of reactive sites. At this time, it is necessary to extend the holding time of each temperature segment to ensure that the curing reaction is fully carried out and effectively release the interfacial thermal residual stress generated by curing shrinkage.

[0075] Understandably, the third curing strategy is for cases where the curing coefficient is less than the second preset curing coefficient. In this case, the system non-uniformity is most significant. At 40℃, the holding time needs to be extended to promote the resin to fully wet the filler surface. At 85℃, the holding time needs to be further extended to ensure the initial formation of the cross-linking network. At 120℃, an even longer holding time is required to fully release the residual stress. The second curing strategy is for cases where the second preset curing coefficient is ≤ curing coefficient < the first preset curing coefficient, and the holding time is appropriately reduced. The first curing strategy is for cases where K ≥ the first preset curing coefficient. In this case, the system uniformity is good, and the standard holding time can be used to ensure that the degree of curing meets the standard. The holding time of each segment of the three curing strategies was verified by DSC isothermal curing experiments to ensure that the degree of curing reaches more than 95%.

[0076] Specifically, this invention employs an orientation treatment process, placing the coated slurry in an environment of 5℃ to 15℃. This significantly increases the viscosity of the epoxy resin without reaching the gel point, suppressing the Brownian motion of the modified filler particles. Simultaneously, the polarity difference between the hydrophilic and hydrophobic hemispheres drives the directional migration of the particles, ensuring that the hydrophilic hemispheres are stably oriented towards the substrate and the hydrophobic hemispheres towards the air interface. This enhances the orientational order of the particles, ensuring the enrichment of hydrophobic groups on the coating surface and the uniform distribution of interfacial bonding density. Furthermore, the curing coefficient is calculated based on the curing exothermic peak width and peak temperature of the coating slurry, and a curing strategy is determined accordingly. A narrow curing exothermic peak width indicates uniform filler distribution, allowing for sufficient cross-linking with a standard curing time. Conversely, a broad exothermic peak indicates poor system uniformity, necessitating an extended post-curing holding time to ensure complete resin reaction and full release of interfacial residual thermal stress, preventing microcrack initiation. This achieves both modified filler orientation and curing stress elimination, ensuring the coating possesses both wear resistance and anti-fouling properties.

[0077] The present invention provides a wear-resistant and stain-resistant protective coating for imitation stone surfaces, wherein the imitation stone surface protective coating is composed of the following raw materials in parts by weight: 30-50 parts modified filler, 50-70 parts epoxy resin, 5-15 parts pigment, 0.3-0.8 parts leveling agent, and 0.2-0.5 parts defoamer; The modified filler is an inorganic filler that has undergone hydrophilic and hydrophobic modification treatment at the interface of Pickering emulsion, and the inorganic filler is one or more of quartz sand, calcium carbonate, and silicon dioxide. The epoxy resin is E-51 bisphenol A type epoxy resin; The pigment is one or more of iron oxide red, iron oxide yellow, iron oxide black, and titanium dioxide; The leveling agent is BYK-331; The defoamer is BYK-054.

[0078] Example 1 Quartz sand with a purity ≥99.5%, a dosage of 100g, and a D50 of 55μm was used. The mixture was modified using Pickering emulsion interface partitioning. The amount of hydrophilic modification KH-550 was 0.5% of the inorganic filler mass, and the amount of hydrophobic modification FDTS was 0.8% of the inorganic filler mass, resulting in 40 parts modified filler, 60 parts E-51 bisphenol A epoxy resin, 10 parts iron oxide black, 0.5 parts BYK-331 leveling agent, and 0.3 parts BYK-054 defoamer.

[0079] 100g of quartz sand was mixed with 400mL of deionized water and ultrasonically dispersed for 20min to obtain an aqueous suspension. 200mL of paraffin was heated to 65℃ and melted, then added to the aqueous suspension and emulsified at 10000rpm for 8min to form a Pickering emulsion. 0.5g of KH-550 was added to the aqueous phase and 0.8g of FDTS was added to the oil phase. The mixture was stirred at 65℃ for 1.5h, cooled, and then demulsified with anhydrous ethanol. After washing, the mixture was vacuum dried at 80℃ for 4h to obtain the modified filler. The first contact angle was measured to be 93°, the second contact angle to be 125°, and the third contact angle to be 55°, confirming that the modified filler is qualified. Take 40 parts of modified filler and 60 parts of epoxy resin, mix them, stir at 400 rpm for 20 min, let stand and age for 30 min, and measure the sedimentation rate: 0.04 mm / min, polarity coefficient: 0.24, migration coefficient: 0.745, which is less than 0.90. Add 2 parts of polarity modifier propylene glycol methyl ether, let stand for 10 min, and retest the sedimentation rate: 0.042 mm / min, polarity coefficient: 0.62, migration coefficient: 0.905, confirming that the mixture meets the standards. Add 10 parts of iron oxide black, 0.5 parts of BYK-331, and 0.3 parts of BYK-054 to the qualified mixture, disperse at 1000 rpm for 20 min, and vacuum degas for 35 min to obtain a coating slurry. Apply the slurry to the artificial stone substrate with a wet film thickness of 2.0 mm, transfer it to a 10℃ constant temperature oven and let it stand for orientation for 1.5 h, then let it stand at room temperature of 25℃ for 10 min. Take 5 mg of the slurry and DSC to determine the curing exothermic peak width of 43℃, the peak temperature of 131℃, and the curing coefficient of 1.055. Use the first curing strategy, with curing temperatures of 40℃, 85℃, and 120℃, and curing holding times of 40 min, 90 min, and 30 min, respectively, and a heating rate of 1.5℃ / min. Cool with the furnace to obtain a stone-like protective coating.

[0080] Example 2 The modified filler was 30 parts and the epoxy resin was 70 parts, and other conditions were the same as in Example 1; The settling rate was 0.052 mm / min, the polarity coefficient was 0.22, and the calculated migration coefficient was 0.591. The mixture did not meet the standard. After adding 3 parts of the polarity modifier propylene glycol methyl ether and letting it stand for 10 minutes, the settling rate was 0.048 mm / min, the polarity coefficient was 0.31, and the migration coefficient was 0.676. The mixture still did not meet the standard. Due to the high proportion of epoxy resin, the viscosity of the system was too low, and the settling was too fast. In this embodiment, the adjustment was abandoned, and subsequent steps were carried out to examine the boundary properties. The orientation treatment was the same as in Example 1. DSC measured the curing exothermic peak width to be 48°C, the peak temperature to be 128°C, and the curing coefficient to be 0.923. The second curing strategy was adopted, with curing temperatures of 40°C, 85°C, and 120°C, curing holding times of 70 min, 120 min, and 60 min, respectively, and a heating rate of 1.5°C / min. The mixture was then cooled in the furnace to obtain a stone-like protective coating.

[0081] Example 3 The modified filler and epoxy resin were used in 50 parts, and other conditions were the same as in Example 1. The settling rate is 0.032 mm / min, the polarity coefficient is 0.38, and the calculated migration coefficient is 0.971, indicating that the mixture meets the standards. The orientation treatment was the same as in Example 1. DSC measured the curing exothermic peak width to be 41°C, the peak temperature to be 132°C, and the curing coefficient to be 1.114. The first curing strategy was adopted, with curing temperatures of 40°C, 85°C, and 120°C, curing holding times of 40 min, 90 min, and 30 min, respectively, and a heating rate of 1.5°C / min. The mixture was then cooled in the furnace to obtain a stone-like protective coating.

[0082] Comparative Example 1 Using conventional globally modified fillers without Pickering emulsion interface partitioning, quartz sand filler was globally grafted with KH-550 coupling agent for modification. 40 parts of the modified filler were mixed with 60 parts of epoxy resin and allowed to stand for 30 minutes without measuring the migration coefficient. After coating, orientation treatment was performed at 10℃ for 1.5 hours. DSC analysis of the coating slurry showed a curing exothermic peak width of 52℃, a peak temperature of 126℃, and a curing coefficient of 0.84. A third curing strategy was adopted, with curing temperatures of 40℃, 85℃, and 120℃, and curing times of 100min, 150min, and 90min, respectively. The heating rate was 1.5℃ / min, followed by furnace cooling to obtain a stone-like protective coating.

[0083] Comparative Example 2 This comparative example uses the same modified filler as in Example 1. 40 parts of the modified filler are mixed with 60 parts of epoxy resin, allowed to stand for 30 minutes, and the sedimentation rate and polarity coefficient are not measured, the migration coefficient is not calculated, and no adjustments are made. After coating, orientation treatment is performed, with a holding temperature of 10°C and a holding time of 1.5 hours. The coating slurry is subjected to DSC analysis. The curing exothermic peak width is 46°C, the peak temperature is 129°C, and the curing coefficient is 0.97. A second curing strategy is adopted, with curing temperatures of 40°C, 85°C, and 120°C, and curing holding times of 70 minutes, 120 minutes, and 60 minutes, respectively. The heating rate is 1.5°C / min, followed by furnace cooling to obtain a stone-like protective coating.

[0084] Comparative Example 3 This comparative example uses the same modified filler and mixing steps as Example 1, including migration coefficient determination and adjustment, to ensure that the mixture meets the standards. However, after coating, no orientation treatment is performed. Instead, the coating is left to stand at room temperature of 25°C for 30 minutes. The coating slurry is then subjected to DSC measurement. The curing exothermic peak width is 44°C, the peak temperature is 131°C, and the curing coefficient is 1.03. The first curing strategy is adopted, with curing temperatures of 40°C, 85°C, and 120°C, and curing holding times of 40 minutes, 90 minutes, and 30 minutes, respectively. The heating rate is 1.5°C / min, followed by furnace cooling to obtain a stone-like protective coating.

[0085] Comparative Example 4 This comparative example uses the same modified filler, mixing steps, and orientation treatment as Example 1, but does not calculate the curing coefficient during curing, does not adjust the curing holding time according to the curing coefficient, and directly adopts the first curing strategy. The curing temperatures are 40℃, 85℃, and 120℃, and the curing holding times are fixed at 40 minutes, 90 minutes, and 30 minutes, respectively. The heating rate is 1.5℃ / min, and then the furnace is cooled to obtain a stone-like protective coating.

[0086] Comparative Example 5 This comparative example uses the simplest process, omitting several steps. It uses conventional globally modified fillers, the same as in Comparative Example 1, without determining the migration coefficient. It is left to stand for 30 minutes without orientation treatment. The first curing strategy is used during curing, with curing temperatures of 40℃, 85℃, and 120℃, and curing holding times of 40 minutes, 90 minutes, and 30 minutes, respectively. The heating rate is 1.5℃ / min, followed by furnace cooling, to obtain a stone-like protective coating.

[0087] The stone-like protective coatings prepared in all embodiments and comparative examples of this invention were subjected to performance tests according to the following methods: (1) Abrasion resistance: The Taber abrasion tester, model Taber 5135, was used with CS-10 grinding wheel, load 1kg, speed 60rpm, and the coating mass loss was measured after 1000 revolutions. Each group of samples was tested 3 times and the average value was taken.

[0088] (2) Anti-fouling: The hydrophobicity of the coating surface was characterized by water contact angle. A contact angle measuring instrument, model KRÜSS DSA100, was used. 2μL of deionized water was added and the static contact angle was measured at 25℃. Five different positions were measured for each sample and the average value was taken. At the same time, a soy sauce stain test was conducted: commercially available light soy sauce was added to the coating surface, left to stand for 2 hours, and then wiped with a damp cloth to observe the residue.

[0089] (3) Adhesion: The pull-off method was adopted. A tensile testing machine, model Instron 5965, was used to bond the aluminum test column to the coating surface with epoxy resin adhesive. After curing, it was stretched vertically to test the adhesion between the coating and the substrate. Each group of samples was tested 5 times and the average value was taken.

[0090] (4) Impact resistance: A drop hammer impact tester with a hammer weight of 1kg was used to drop the coating surface from a height of 50cm and observe whether the coating cracked or peeled off.

[0091] Table 1 Results of coating performance tests in examples and comparative examples

[0092] Comparative Example 1 used conventional KH-550 globally modified filler without Pickering emulsion interface partitioning treatment. Its abrasion loss was as high as 46 mg / 100 r, its water contact angle was only 84°, and its adhesion was 6.2 N / mm. 2 The impact resistance showed microcracks, and soy sauce residue was obvious. Compared with Example 1, the wear rate increased by 109%, the water contact angle decreased by 30°, and the adhesion decreased by 33%. This proves that the present invention modifies the two hemispheres of the filler by hydrophilic and hydrophobic modification through Pickering emulsion interface partitioning, so that the same particle has active sites covalently bonded to epoxy resin and antifouling groups that impart low surface energy to the surface. This resolves the contradiction between wear resistance and antifouling. The filler without partitioning modification is either too hydrophilic, resulting in poor antifouling, or too hydrophobic, resulting in weak interfacial bonding, and cannot meet the two performance requirements at the same time.

[0093] Comparative Example 2 used the same partitioned modified filler as Example 1, but after static aging, the settling rate and polarity coefficient were not measured, the migration coefficient was not calculated, and no adjustments were made. The abrasion loss was 36 mg / 100 r, the water contact angle was 102°, and the adhesion was 8.0 N / mm. 2 Compared to Example 1, the wear rate increased by 64%, the water contact angle decreased by 12°, and the adhesion decreased by 14%. This indicates that without the determination of the migration coefficient and conditional adjustment, the orientation quality of particles in the resin cannot be quantitatively controlled, resulting in insufficient enrichment of hydrophobic groups on the coating surface and uneven interfacial bonding density. This invention constructs a migration coefficient by using the sedimentation rate and polarity coefficient, thereby achieving pre-quantitative control of particle orientation behavior. When the migration coefficient does not meet the standard, it is adjusted by adding a polarity modifier, which improves the wear resistance, antifouling performance, and batch stability of the coating.

[0094] Comparative Example 3 used the same partitioned modified filler and migration coefficient adjustment as Example 1, but instead of undergoing orientation treatment at 5°C–15°C after coating, it was left to stand at room temperature for 30 minutes. The abrasion loss was 33 mg / 100 r, the water contact angle was 106°, and the adhesion was 8.3 N / mm. 2Compared to Example 1, the wear rate increased by 50%, the water contact angle decreased by 8°, and the adhesion decreased by 11%. This demonstrates that in a low-temperature environment of 5°C to 15°C, the viscosity of the epoxy resin increases significantly, the Brownian motion of the particles is effectively suppressed, and the polarity difference between the hydrophilic and hydrophobic hemispheres is used to drive the directional migration of the particles, so that the hydrophilic hemispheres are stably oriented towards the substrate and the hydrophobic hemispheres are oriented towards the air interface, increasing the particle orientation from about 70% to more than 85%, thereby enhancing the hydrophobicity of the coating surface and the interfacial bonding strength inside.

[0095] Comparative Example 4 used the same partitioned modified filler, migration coefficient determination, and orientation treatment as Example 1, but the curing coefficient was not calculated during curing, and the first curing strategy was always used. The abrasion loss was 29 mg / 100 r, the water contact angle was 112°, and the adhesion was 7.6 N / mm. 2 The impact resistance showed fine cracks, and the adhesion decreased by 18% compared to Example 1. This indicates that the lack of adaptive control of the curing coefficient means that even if the preceding steps meet the standards, the residual thermal stress during the curing process cannot be effectively eliminated. This invention calculates the curing coefficient by using the curing exothermic peak width and peak temperature. When the curing exothermic peak width is narrow, it indicates that the filler is evenly distributed, and the standard curing time is sufficient for full cross-linking. When the exothermic peak width is broad, it indicates that the system uniformity is poor. Extending the post-curing heat preservation time allows the resin to fully react and release the interfacial thermal stress, avoiding the initiation of microcracks and ensuring adhesion.

[0096] Comparative Example 5 omits Pickering emulsion interfacial partitioning modification, migration coefficient determination, orientation treatment, and DSC adaptive curing, employing the simplest process. It achieves a wear rate as high as 51 mg / 100 r, a water contact angle of only 78°, and an adhesion of only 5.5 N / mm. 2 The impact resistance showed obvious cracks, and there was serious soy sauce residue. This, from the opposite perspective, verified the synergistic effect of each step of the invention: the partition modification ensured the polar partitioning of the filler, the migration coefficient determination ensured the orientation quality of the particles in the resin, the orientation treatment locked the orientation direction, and the DSC curing coefficient adaptively eliminated the interfacial thermal residual stress.

[0097] This invention solves the technical problem of achieving both wear resistance and stain resistance in imitation stone protective coatings by using Pickering emulsion interface partitioning modification, triple contact angle determination, migration coefficient quantitative control, orientation treatment, and DSC curing coefficient curing strategy. The performance indicators of Examples 1 to 3 are significantly better than those of the comparative examples.

[0098] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a wear-resistant and stain-resistant protective coating for imitation stone surfaces, characterized in that, include: Inorganic fillers are dispersed in an oil-water two-phase system to form a Pickering emulsion. Based on the partitioning of the oil-water interface, the inorganic filler hemispheres facing the water phase are hydrophilic modified, and the inorganic filler hemispheres facing the oil phase are hydrophobic modified. Demulsification and separation are then performed to obtain the modified filler. The qualification of the modified packing is determined based on the first contact angle of the modified packing and the second and third contact angles of the two hemispheres of the modified packing. In response to the qualified modified filler, the modified filler is mixed with epoxy resin and allowed to stand for aging to obtain a mixture. The migration coefficient is determined based on the settling rate and polarity coefficient of the mixture to determine whether the mixture meets the standard. In response to the compliance of the mixture, the mixture is mixed and dispersed with pigments and additives, and vacuum degassing is performed to obtain a coating slurry. The coating slurry is then coated onto the surface of the substrate for orientation treatment. The curing coefficient is determined based on the curing exothermic peak width and peak temperature of the coating slurry. Based on the curing coefficient, a curing strategy is determined, and a cooling treatment is performed to obtain a protective coating for the imitation stone surface.

2. The method for preparing the wear-resistant and stain-resistant imitation stone surface protective coating according to claim 1, characterized in that, The modified filler is deemed qualified based on the following conditions: the first contact angle is greater than or equal to the first preset contact angle, the second contact angle is greater than or equal to the second preset contact angle, and the third contact angle is less than or equal to the third preset contact angle.

3. The method for preparing the wear-resistant and stain-resistant imitation stone surface protective coating according to claim 1, characterized in that, The process of obtaining the mixture includes: mixing qualified modified filler and epoxy resin at a mass ratio of 30-50:70-50, stirring at a speed of 300-500 rpm, stirring for 15-30 minutes, and allowing to stand for aging for 20-40 minutes.

4. The method for preparing the wear-resistant and stain-resistant imitation stone surface protective coating according to claim 1, characterized in that, Based on the migration coefficient being greater than or equal to the preset migration coefficient, the mixture is determined to meet the standard.

5. The method for preparing the wear-resistant and stain-resistant imitation stone surface protective coating according to claim 4, characterized in that, The migration coefficient is determined by adding the product of the weighting coefficient and the ratio of the settling rate to the product of the weighting coefficient and the polarity coefficient. Wherein, the settling rate ratio is the ratio of a preset settling rate to the settling rate; The polarity coefficient is determined by dividing the difference between the dielectric constant at 2 mm above the bottom of the mixture and the dielectric constant at 2 mm below the liquid surface at the top of the mixture by the sum of the dielectric constants at 2 mm above the bottom of the mixture and the dielectric constants at 2 mm below the liquid surface at the top of the mixture.

6. The method for preparing the wear-resistant and stain-resistant imitation stone surface protective coating according to claim 1, characterized in that, The orientation process includes: uniformly coating the substrate surface with the coating slurry using a scraping method, with a wet film thickness of 1.5mm to 2.5mm; transferring the coated substrate to a constant temperature chamber, maintaining the temperature at 5℃ to 15℃ for 1h to 2h, and then letting it stand at room temperature of 25℃ for 10min.

7. The method for preparing the wear-resistant and stain-resistant imitation stone surface protective coating according to claim 1, characterized in that, Based on the curing coefficient being greater than or equal to the first preset curing coefficient, the curing strategy is determined to be the first curing strategy. The curing coefficient is determined by multiplying the ratio of the preset curing exothermic peak width to the curing exothermic peak width by the ratio of the peak temperature to the preset peak temperature. The curing temperatures of the first curing strategy are 40℃, 85℃ and 120℃, and the curing holding times are 40min, 90min and 30min, respectively.

8. The method for preparing the wear-resistant and stain-resistant imitation stone surface protective coating according to claim 7, characterized in that, Based on the curing coefficient being greater than or equal to the second preset curing coefficient and less than the first preset curing coefficient, the curing strategy is determined to be the second curing strategy. The curing temperatures of the second curing strategy are 40℃, 85℃ and 120℃, and the curing holding times are 70min, 120min and 60min, respectively.

9. The method for preparing the wear-resistant and stain-resistant imitation stone surface protective coating according to claim 8, characterized in that, Based on the fact that the curing coefficient is less than the second preset curing coefficient, the curing strategy is determined to be the third curing strategy. The curing temperatures of the third curing strategy are 40℃, 85℃ and 120℃, and the curing holding times are 100min, 150min and 90min, respectively.

10. A wear-resistant and stain-resistant imitation stone surface protective coating prepared by the method for preparing the wear-resistant and stain-resistant imitation stone surface protective coating according to any one of claims 1-9, characterized in that, The imitation stone surface protective coating is composed of the following raw materials in parts by weight: 30-50 parts modified filler, 50-70 parts epoxy resin, 5-15 parts pigment, 0.3-0.8 parts leveling agent, and 0.2-0.5 parts defoamer; The modified filler is an inorganic filler that has undergone hydrophilic and hydrophobic modification treatment at the interface of Pickering emulsion, and the inorganic filler is one or more of quartz sand, calcium carbonate, and silicon dioxide. The epoxy resin is E-51 bisphenol A type epoxy resin; The pigment is one or more of iron oxide red, iron oxide yellow, iron oxide black, and titanium dioxide; The leveling agent is BYK-331; The defoamer is BYK-054.

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