A marble effect water-borne paint and a method for its preparation

Abstract

The present application is suitable for paint preparation technical field, provide a kind of marble effect water-based paint and preparation method thereof, paint is made of A, B two components, adopts self-crosslinking core-shell structure acrylic emulsion, alkyl grafting cellulose nanocrystal, mesoporous silicon titanium bifunctional composite particle, POSS-hydrazide hybrid modified magnesium lithium silicate as core function material, through microchannel pre-lamination+ electrostatic spinning atomization coupling process granulation, realize heat-pH dual trigger rapid crosslinking film forming.The present application can form continuous permeable, silk luster natural marble vein texture with one spraying, texture simulation degree ≥9.0 minutes, vein continuity ≥90%, light transmittance ≥85%, surface dryness ≤20 minutes, re-coating interval ≤2 hours, viscosity change rate ≤15% after 30 days of 50 ℃ heat storage, with high simulation, fast construction, high stability, low VOC, excellent mechanical properties and other advantages, suitable for high-end stone decoration for building interior and exterior wall.

Description

Technical Field

[0001] This invention belongs to the field of coating preparation technology, and particularly relates to a water-based coating with a marble effect and its preparation method. Background Technology

[0002] Water-based stone-like coatings, due to their advantages such as environmental friendliness, lightweight, and convenient application, are gradually becoming the mainstream choice to replace dry-hanging decoration with natural stone. Existing water-based multicolor coatings are mainly divided into two categories: oil-in-water and water-in-water. Although water-in-water coatings have solved the problem of organic solvent pollution, the following technical bottlenecks still exist: (1) The texture simulation is insufficient, making it difficult to present the silky and transparent feel of natural marble veins. The color particle boundaries are hard and lack a sense of layering. Existing technologies mostly use color paste to adjust the color and then simply mix and granulate. The resulting texture has a discrete particle feel, rather than the continuous and gradual vein direction of natural marble.

[0003] (2) The drying and film-forming speed is slow, and the recoating interval is as long as 24 hours, resulting in low construction efficiency. The main reason is that water-based coatings rely on the evaporation of water to form a film, and the compatibility problem between the protective adhesive system and the emulsion often leads to post-thickening, which further prolongs the drying time.

[0004] (3) The protective colloid system has poor compatibility with the emulsion, is prone to post-thickening, and has poor storage stability. Traditional lithium magnesium silicate protective colloid will undergo a slow flocculation reaction with the emulsion during storage, resulting in increased viscosity or even gelation.

[0005] (4) To obtain a three-dimensional texture, multiple sprayings or manual painting are required, which is a complex process with poor reproducibility. Existing technologies often require first spraying a base color and then using techniques such as dot spraying and texturing to create the texture, which requires high skills from the construction personnel.

[0006] To address the above problems, this invention provides a water-based coating with marble effect that combines high-simulation texture, rapid drying, and excellent storage stability, as well as its preparation method. Summary of the Invention

[0007] This invention provides a water-based coating with a marble effect and a method for preparing the same, aiming to solve the above-mentioned problems.

[0008] This invention is achieved as follows: a water-based coating with a marble effect, composed of component A and component B, wherein the mass ratio of component A to component B is 7:3-8:2. Component A comprises, by weight, the following: High-density base paint: 300-400 parts of self-crosslinking core-shell structure acrylic emulsion, 2-5 parts of alkyl grafted cellulose nanocrystals, 100-150 parts of titanium dioxide, 10-20 parts of silane-modified magnesium lithium silicate, 1-3 parts of wetting agent, and 150-250 parts of deionized water. Low-density microbubble gel: 100-200 parts of self-crosslinking core-shell structured acrylic emulsion, 30-60 parts of mesoporous silica-titanium bifunctional composite particles, 0.3-0.8 parts of microbubble stabilizer, and 0.5-2 parts of thickener; the density of the low-density microbubble gel is 0.6-0.8 g / cm³. 3 ; The B component, by weight, comprises: 100-150 parts of POSS-hydrazide hybrid modified magnesium lithium silicate dispersion, 3-8 parts of adipic acid dihydrazide, 20-40 parts of dipropylene glycol butyl ether, 15-25 parts of isopropanol, 1-3 parts of pH neutralizer, and 50-100 parts of deionized water.

[0009] The coating is prepared by a microchannel-electrostatic field coupling granulation process, wherein the microchannel size is 0.5-1.0 mm and the electrostatic voltage is 20-30 kV.

[0010] Preferably, the self-crosslinked core-shell acrylic emulsion has a core glass transition temperature of -20°C to -10°C and a shell glass transition temperature of 45°C to 55°C, and the shell contains a ketone carbonyl functional group.

[0011] Preferably, the preparation method of the self-crosslinked core-shell structured acrylic emulsion includes the following steps: (1) Core layer pre-emulsification: Dissolve 0.3-0.6 parts by weight of anionic emulsifier and 0.6-1.2 parts by weight of nonionic emulsifier in 15-20 parts by weight of deionized water, add 15-20 parts by weight of butyl acrylate, 5-8 parts by weight of methyl methacrylate and 0.5-1.5 parts by weight of glycidyl methacrylate, and emulsify at 1000-1500 rpm for 20-30 minutes to obtain core layer pre-emulsified solution; (2) Shell pre-emulsification: Dissolve 0.15-0.3 parts by weight of anionic emulsifier and 0.3-0.6 parts by weight of nonionic emulsifier in 8-12 parts by weight of deionized water, add 20-25 parts by weight of methyl methacrylate, 3-6 parts by weight of ethyl acrylate, 1-2 parts by weight of diacetone acrylamide and 0.5-1 parts by weight of methacrylic acid, and emulsify at 1000-1500 rpm for 20-30 minutes to obtain shell pre-emulsion; (3) Seed polymerization: At 75-85℃, add 5-15% of the total amount of the core layer pre-emulsion and 0.1-0.2 parts by weight of ammonium persulfate, and keep the reaction at the temperature for 20-40 minutes to form seeds; (4) Core layer polymerization: At 80-85℃, the remaining core layer pre-emulsion and 0.1-0.2 parts by weight of ammonium persulfate solution are added dropwise over 2-3 hours, and the mixture is kept warm for 0.5-1.5 hours. (5) Shell polymerization: Add shell pre-emulsion and 0.05-0.15 parts by weight of ammonium persulfate solution dropwise at 80-85℃, complete the addition in 1.5-2.5 hours, and keep warm for 1.5-2.5 hours; (6) Post-treatment: Cooling and filtration to obtain a self-crosslinked core-shell acrylic emulsion with a solid content of 45±1%.

[0012] Preferably, the preparation method of the alkyl-grafted cellulose nanocrystals includes the following steps: (1) Dispersion: Add 1 part by weight of cellulose nanocrystals to 15-25 parts by weight of N,N-dimethylformamide and disperse by ultrasonication for 20-40 minutes; (2) Grafting reaction: Add 0.1-0.3 parts by weight of pyridine, slowly add 0.4-0.8 parts by weight of C12-C16 long-chain alkyl acyl chloride, and react at 60-80℃ for 4-8 hours; (3) Washing and separation: After the reaction is completed, add 50-80 parts by weight of anhydrous ethanol to precipitate, centrifuge and then wash with anhydrous ethanol and deionized water 2-3 times each. (4) Drying: Vacuum drying at 45-55℃ for 20-28 hours to obtain alkyl-grafted cellulose nanocrystals with an alkyl grafting rate of 5-15%.

[0013] Preferably, the mesoporous silicon-titanium bifunctional composite particles are prepared by a method comprising the following steps: (1) Preparation of amino-modified silica particles: Dissolve 1-1.5 parts by weight of tetraethyl orthosilicate in 5-8 parts by weight of anhydrous ethanol, and slowly drop it into 10-15 parts by weight of an aqueous ethanol solution containing 0.8-1.2 parts by weight of ammonia. React at 25-35°C for 10-14 hours. After modification with aminopropyltrimethoxysilane, amino-modified silica particles are obtained. (2) Disperse amino-modified silica particles in 4-6 parts by weight of melted paraffin, add 25-35 parts by weight of deionized water, emulsify at 75-85℃ and 800-1200rpm for 0.5-1.5 hours to form Pickering emulsion, and cool and solidify to obtain colloidal template; (3) Selectively grow titanium dioxide on the surface of the colloidal body, wash it by centrifugation, remove the paraffin template with 50-100 parts by weight of cyclohexane, and calcine at 400-500℃ for 2-4 hours to obtain mesoporous silicon-titanium bifunctional composite particles.

[0014] Preferably, the preparation method of the POSS-hydrazide hybrid modified lithium magnesium silicate dispersion is as follows: lithium magnesium silicate is added to 35-45 parts by weight of deionized water, stirred and exfoliated at 1000-1200 rpm for 24-48 hours, the lithium magnesium silicate dispersion is mixed with amino POSS and adipic acid dihydrazide at a mass ratio of 100:(2-5):(3-8), 0.5-1.0% by weight of glutaraldehyde is added to the lithium magnesium silicate, and the mixture is reacted at 50-70℃ for 6-10 hours. After spray drying, the mixture is then dispersed in deionized water to prepare a dispersion with a solid content of 8-12%.

[0015] Preferably, the wetting agent is a nonionic wetting agent; the microbubble stabilizer is sodium dodecyl sulfate; the thickener is an alkali-swellable acrylic thickener; and the pH neutralizer is AMP-95 or ammonia.

[0016] This invention also provides a method for preparing the above-mentioned water-based marble effect coating, comprising the following steps: (1) Preparation of high-density base paint: Dissolve alkyl grafted cellulose nanocrystals in deionized water, add self-crosslinked core-shell structure acrylic emulsion, titanium dioxide, silane-modified magnesium lithium silicate, and wetting agent, and disperse at 800-1000 rpm for 30-40 minutes; (2) Preparation of low-density microbubble gel: Mix self-crosslinked core-shell structured acrylic emulsion, mesoporous silica-titanium bifunctional composite particles, microbubble stabilizer, and thickener, stir at 200-400 rpm, and microbubble until the density is 0.6-0.8 g / cm³. 3 ; (3) Microchannel pre-stacked sheets: High-density base paint and low-density microbubble gel are fed into a 0.5-1.0mm microchannel mixer at a ratio of 7:3-8:2 to form laminar flow stacked micro-clusters; (4) Preparation of component B: POSS-hydrazide hybrid modified magnesium lithium silicate dispersion, adipic acid dihydrazide, dipropylene glycol butyl ether, isopropanol, pH neutralizer and deionized water are mixed and stirred at 400-600 rpm for 20-30 minutes. (5) Electrospinning atomization granulation: The laminar flow stacked micro-particles are conveyed to the electrospinning atomization nozzle and atomized under a voltage of 20-30kV. At the same time, component B is conveyed to the nozzle and mixed with the micro-particles. The mixture is then sprayed onto the substrate surface to form a marble texture coating. The coating is cured at 20-30℃ and 40-60% humidity for 5-7 days.

[0017] Preferably, the airflow pressure for electrospinning atomization in step (5) is 0.2-0.4 MPa.

[0018] Preferably, in step (5), the sprayed film thickness is 150-200μm, the surface drying time is ≤20 minutes, the complete drying time is ≤4 hours, and the recoating interval is ≤2 hours.

[0019] Compared with the prior art, the embodiments of this application have the following main advantages: The waterborne coating with marble effect provided by this invention uses alkyl grafted cellulose nanocrystals (CNC) as a gel carrier, combined with low-density microbubble gel stabilized by mesoporous silica-titanium bifunctional composite particles, and utilizes density difference and rheological properties to form a continuous vein structure like natural marble in a shear field.

[0020] A core-shell emulsion with a low Tg (-20℃ to -10℃) core layer and a high Tg (45℃ to 55℃) shell layer containing ketone carbonyl groups is used in conjunction with a POSS-acylhydrazine hybrid modified lithium magnesium silicate protective adhesive. After application, the temperature rise triggers shell layer softening and the pH drop triggers ketone hydrazine crosslinking, achieving rapid film formation through heat-pH ​​dual triggering. The surface drying time is ≤20 minutes and the recoating interval is ≤2 hours.

[0021] The interfacial enhancement effect of POSS nano-anchors and mesoporous silicon-titanium bifunctional composite particles improves the wear resistance of the coating film. Attached Figure Description

[0022] Figure 1 This is a flowchart of a method for preparing a water-based coating with a marble effect provided by the present invention.

[0023] Figure 2 This is a comparison image of the marble texture appearance of the coating sample of Embodiment 1 of the present invention and the traditional water-in-water coating sample.

[0024] Figure 3 This is a comparison diagram of the coating texture morphology of Embodiment 1 and Comparative Example 7 of the present invention. Detailed Implementation

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0026] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0027] I. Preparation method of self-crosslinked core-shell structured acrylic emulsion (1) Preparation of core layer pre-emulsion: 3g SDS and 6g OP-10 were added to 150g deionized water and stirred to dissolve. Then, 150g BA, 50g MMA and 5g GMA were slowly added and emulsified at 1200rpm for 25 minutes to obtain core layer pre-emulsion.

[0028] (2) Preparation of shell preemulsion: 1.5g SDS and 3g OP-10 were added to 100g deionized water and stirred to dissolve. Then, 200g MMA, 30g EA, 10g DAAM and 5g MAA were slowly added and emulsified at 1200rpm for 25 minutes to obtain shell preemulsion.

[0029] (3) Seed polymerization: Add 200g of deionized water and 2g of sodium bicarbonate to a 1000mL four-necked flask equipped with a stirrer, reflux condenser, thermometer and dropping funnel, and heat to 78℃; add 10% of the total amount of core layer pre-emulsion, add 1g of ammonium persulfate (dissolved in 10g of water), keep warm for 30 minutes, and the system shows blue fluorescence, indicating that the seeds have formed.

[0030] (4) Core layer polymerization: At 82°C, the remaining core layer pre-emulsion and initiator solution (1.5g APS dissolved in 50g water) are added dropwise simultaneously, and the dropping speed is controlled to be completed in 3 hours; keep warm for 1 hour.

[0031] (5) Shell polymerization: At 82°C, add shell pre-emulsion and initiator solution (1g APS dissolved in 40g water) dropwise, control the dropping speed and finish dropping over 2 hours; keep warm for 2 hours.

[0032] (6) Post-processing: Cool to below 40℃ and filter through a 200-mesh filter cloth to obtain a self-crosslinked core-shell acrylic emulsion. The solid content was found to be 45±1%, the core layer Tg was about -15℃, and the shell layer Tg was about 50℃.

[0033] II. Preparation method of alkyl-grafted cellulose nanocrystals (1) Dispersion: Add 10g of cellulose nanocrystals to 200mL of DMF and ultrasonically disperse for 30 minutes (power 300W, frequency 40kHz) to obtain a semi-transparent dispersion.

[0034] (2) Grafting reaction: Add 2g of pyridine to the dispersion, stir evenly, and slowly add 6g of C12-C16 long-chain alkyl acyl chloride, controlling the dropping rate to about 1mL / min; after the dropping is completed, raise the temperature to 70℃, and react at a constant temperature for 6 hours, stirring at 350rpm.

[0035] (3) Washing and separation: After the reaction is complete, pour the reaction solution into 500 mL of anhydrous ethanol, stir for 10 minutes, and let it stand to precipitate. Centrifuge at 8000 rpm for 10 minutes and discard the supernatant. Wash the precipitate twice with anhydrous ethanol and twice with deionized water, centrifuging after each wash.

[0036] (4) Drying: The washed product was placed in a vacuum drying oven and dried at 50°C for 24 hours to obtain white powdery alkyl-grafted cellulose nanocrystals. The grafting rate was determined to be approximately 12% by thermogravimetric analysis (TGA).

[0037] III. Preparation Method of Mesoporous Silicon-Titanium Bifunctional Composite Particles (1) Preparation of amino-modified SiO2 particles: Dissolve 1-1.5 parts by weight of tetraethyl orthosilicate in 5-8 parts by weight of anhydrous ethanol, and slowly add it dropwise to 10-15 parts by weight of an aqueous ethanol solution containing 0.8-1.2 parts by weight of ammonia. React at 25-35℃ for 10-14 hours, centrifuge at 8000 rpm, and wash three times with ethanol to obtain SiO2 particles. Disperse 1g of SiO2 particles in 50mL of toluene, add 0.8mL of APTMS, reflux at 110℃ for 6 hours, centrifuge, wash three times with ethanol, and dry at 50℃ to obtain amino-modified SiO2 particles.

[0038] (2) Formation of colloid: 0.3g of amino-modified SiO2 particles were dispersed in 5g of molten paraffin (75℃) and stirred for 10 minutes to make the particles uniformly dispersed; 30mL of deionized water (preheated to 75℃) was added and stirred at 1000rpm for 1 hour to form a stable Pickering emulsion; cooled to room temperature, the paraffin solidified, and filtered to obtain paraffin microspheres encapsulating SiO2 particles, which were washed with deionized water to remove free particles.

[0039] (3) Selective growth of TiO2: Disperse 3g of colloid in 20mL of anhydrous ethanol, add 0.075g of hydroxyethyl cellulose and 0.202g of water, and stir evenly; dissolve 1.02g of TBOT in 5mL of anhydrous ethanol and slowly add it dropwise to the above dispersion; shake at 40℃ and 200rpm for 3 hours, centrifuge and wash, and repeat the coating 1-2 times.

[0040] (4) Template removal and calcination: The product was dispersed in 80 mL of cyclohexane and stirred for 30 minutes to dissolve the paraffin. The product was then centrifuged. The product was washed twice with cyclohexane. The resulting powder was placed in a muffle furnace and heated to 450 °C at 5 °C / min. The powder was then calcined for 3 hours. After cooling, the powder was ground to obtain mesoporous silica-titanium bifunctional composite particles.

[0041] IV. Preparation method of POSS-hydrazide hybridized modified lithium magnesium silicate (1) Lithium magnesium silicate stripping: 20g of lithium magnesium silicate was slowly added to 800mL of deionized water and stirred at 1200rpm for 2 hours. The stirring speed was then reduced to 400rpm and stirred for 36 hours to obtain a semi-transparent gel-like dispersion.

[0042] (2) Preparation of POSS-ADH prepolymer: Dissolve 2g POSS-NH2 in 20mL anhydrous ethanol and 6g ADH in 30mL deionized water; mix the two, add 0.1g glutaraldehyde, adjust the pH to 6.8 (pH adjuster is AMP-95), and react in a water bath at 50℃ for 2 hours to obtain POSS-ADH prepolymer solution.

[0043] (3) Hybrid modification: The prepolymer solution was slowly added to the lithium magnesium silicate dispersion at a dropping rate of 5-10 mL / min and a stirring speed of 500 rpm. After the addition was completed, the temperature was raised to 60℃ and the reaction was carried out for 8 hours.

[0044] (4) Drying and redispersing: spray drying (inlet temperature 190℃, outlet temperature 85℃) to obtain powder, which is then redispersed in deionized water to prepare a dispersion with a solid content of 10%.

[0045] Example 1 (1) Raw material ratio Component A: High-density base paint: 350 parts of self-crosslinking core-shell structure acrylic emulsion, 3 parts of alkyl grafted cellulose nanocrystals, 120 parts of titanium dioxide, 15 parts of silane-modified magnesium lithium silicate, 2 parts of wetting agent, and 200 parts of deionized water. Low-density microbubble gel: 150 parts of self-crosslinking core-shell structured acrylic emulsion, 45 parts of mesoporous silica-titanium bifunctional composite particles, 0.5 parts of microbubble stabilizer, and 1 part of thickener; density controlled to 0.7 g / cm³ through microbubbling. 3 .

[0046] Component B: 120 parts of POSS-hydrazide hybrid modified magnesium lithium silicate dispersion (10% solid content), 5 parts of adipic acid dihydrazide, 30 parts of dipropylene glycol butyl ether, 20 parts of isopropanol, 2 parts of AMP-95, and 80 parts of deionized water.

[0047] The mass ratio of component A to component B is 7:3.

[0048] (2) Preparation process ① Preparation of high-density base paint: Alkyl grafted cellulose nanocrystals are dissolved in deionized water, and self-crosslinked core-shell structured acrylic emulsion, titanium dioxide, silane-modified magnesium lithium silicate, and wetting agent are added. The mixture is dispersed at 900 rpm for 35 minutes to obtain high-density base paint.

[0049] ② Preparation of low-density microbubble gel: A self-crosslinked core-shell structured acrylic emulsion, mesoporous silica-titanium bifunctional composite particles, microbubble stabilizer, and thickener were mixed and stirred evenly at 300 rpm. Air was introduced through a microbubble device to control the density to 0.7 g / cm³. 3 A low-density microbubble gel was obtained.

[0050] ③ Microchannel pre-stacked sheets: High-density base paint and low-density microbubble gel are pumped into a 0.8mm microchannel mixer at a mass ratio of 7:3 to form multi-layer stacked micro-clusters under laminar flow conditions.

[0051] ④ Preparation of component B: POSS-hydrazide hybrid modified magnesium lithium silicate dispersion, adipic acid dihydrazide, dipropylene glycol butyl ether, isopropanol, AMP-95, and deionized water are mixed and stirred at 500 rpm for 25 minutes to obtain component B.

[0052] ⑤ Electrospinning atomization granulation: The micro-particles obtained in step ③ are conveyed to the electrospinning atomization nozzle and atomized under the conditions of 25kV voltage and 0.3MPa air pressure. At the same time, component B is conveyed to the nozzle and mixed with the micro-particles (the conveying flow ratio of component B to component A micro-particles is 3:7). The mixture is sprayed onto tinplate or cement fiberboard substrate, and the film thickness is controlled at 150-200μm. The performance is tested after curing at 25℃ and 50% humidity for 7 days.

[0053] Example 2 It is basically the same as Example 1, except that: Component A: High-density base paint contains 300 parts self-crosslinking core-shell structured acrylic emulsion, 5 parts alkyl-grafted cellulose nanocrystals, 100 parts titanium dioxide, 10 parts silane-modified magnesium lithium silicate, 1 part wetting agent, and 150 parts deionized water; Low-density microbubble gel contains 100 parts self-crosslinking core-shell structured acrylic emulsion, 30 parts mesoporous silica-titanium bifunctional composite particles, 0.3 parts microbubble stabilizer, and 0.5 parts thickener, with a density of 0.6 g / cm³. 3 ; Component B: 100 parts of POSS-hydrazide hybrid modified magnesium lithium silicate dispersion, 3 parts of adipate dihydrazide, 20 parts of dipropylene glycol butyl ether, 15 parts of isopropanol, 1 part of AMP-95, and 50 parts of deionized water; Process parameters: microchannel size 0.5mm, electrostatic voltage 20kV, airflow pressure 0.2MPa.

[0054] Example 3 It is basically the same as Example 1, except that: Component A: High-density base paint contains 400 parts self-crosslinking core-shell structured acrylic emulsion, 5 parts alkyl-grafted cellulose nanocrystals, 150 parts titanium dioxide, 20 parts silane-modified magnesium lithium silicate, 3 parts wetting agent, and 250 parts deionized water; Low-density microbubble gel contains 200 parts self-crosslinking core-shell structured acrylic emulsion, 60 parts mesoporous silica-titanium bifunctional composite particles, 0.8 parts microbubble stabilizer, and 2 parts thickener, with a density of 0.8 g / cm³. 3 ; Component B: 150 parts of POSS-hydrazide hybrid modified magnesium lithium silicate dispersion, 8 parts of adipate dihydrazide, 40 parts of dipropylene glycol butyl ether, 25 parts of isopropanol, 3 parts of AMP-95, and 100 parts of deionized water; Process parameters: microchannel size 1.0mm, electrostatic voltage 30kV, airflow pressure 0.4MPa.

[0055] Example 4 It is basically the same as Example 1, except that: Component A: High-density base paint contains 320 parts self-crosslinking core-shell structured acrylic emulsion, 2.5 parts alkyl-grafted cellulose nanocrystals, 110 parts titanium dioxide, 12 parts silane-modified magnesium lithium silicate, 1.5 parts wetting agent, and 180 parts deionized water; low-density microbubble gel contains 120 parts self-crosslinking core-shell structured acrylic emulsion, 38 parts mesoporous silica-titanium bifunctional composite particles, 0.4 parts microbubble stabilizer, and 0.8 parts thickener, with a density of 0.65 g / cm³. 3 ; Component B: 110 parts of POSS-hydrazide hybrid modified magnesium lithium silicate dispersion, 4 parts of adipate dihydrazide, 25 parts of dipropylene glycol butyl ether, 18 parts of isopropanol, 1.5 parts of AMP-95, and 65 parts of deionized water; Process parameters: microchannel size 0.6mm, electrostatic voltage 22kV, airflow pressure 0.25MPa.

[0056] Example 5 It is basically the same as Example 1, except that: Component A: High-density base paint contains 380 parts of self-crosslinking core-shell structured acrylic emulsion, 4 parts of alkyl-grafted cellulose nanocrystals, 135 parts of titanium dioxide, 18 parts of silane-modified magnesium lithium silicate, 2.5 parts of wetting agent, and 220 parts of deionized water; Low-density microbubble gel contains 180 parts of self-crosslinking core-shell structured acrylic emulsion, 52 parts of mesoporous silica-titanium bifunctional composite particles, 0.6 parts of microbubble stabilizer, and 1.5 parts of thickener, with a density of 0.75 g / cm³. 3 ; Component B: 135 parts of POSS-hydrazide hybrid modified magnesium lithium silicate dispersion, 6 parts of adipate dihydrazide, 35 parts of dipropylene glycol butyl ether, 22 parts of isopropanol, 2.5 parts of AMP-95, and 90 parts of deionized water; Process parameters: microchannel size 0.9mm, electrostatic voltage 28kV, airflow pressure 0.35MPa.

[0057] Comparative Example 1 (CNC without alkyl grafting) It is basically the same as Example 1, except that no alkyl grafted cellulose nanocrystals are added to the high-density base paint, while other components and processes remain unchanged.

[0058] Comparative Example 2 (without added mesoporous silicon-titanium bifunctional composite particles) It is basically the same as Example 1, except that: no mesoporous silicon-titanium bifunctional composite particles are added to the low-density microbubble gel, while other components and processes remain unchanged.

[0059] Comparative Example 3 (Lithium Magnesium Silicate without Silane Modification) It is basically the same as Example 1, except that no silane-modified magnesium lithium silicate is added to the high-density base paint, while other components and processes remain unchanged.

[0060] Comparative Example 4 (without POSS-hydrazide hybrid magnesium silicate) The process is basically the same as in Example 1, except that: POSS-hydrazide hybrid modified magnesium lithium silicate dispersion is not added to component B, but instead an equal amount of deionized water is added, while other components and processes remain unchanged.

[0061] Comparative Example 5 (without ADH) It is basically the same as Example 1, except that: adipic acid dihydrazide is not added to component B, while other components and processes remain unchanged.

[0062] Comparative Example 6 (without pH neutralizer) It is basically the same as Example 1, except that AMP-95 is not added to component B, while other components and processes remain unchanged.

[0063] Comparative Example 7 (without electrospinning atomization) The process is basically the same as in Example 1, except that step ⑤ uses conventional air spraying with an electrostatic voltage of 0 kV, while other components and processes remain unchanged.

[0064] Performance testing methods Tests were conducted in accordance with relevant national standards and industry-standard methods. Texture simulation evaluation: A review panel of 10 professional painting engineers was invited to conduct blind evaluation and scoring of the sprayed samples (out of 10 points), and to comprehensively evaluate the samples from three dimensions: texture clarity, vein naturalness, and transparency.

[0065] Vein continuity: Five fields of view were randomly selected from the sprayed sample using a stereomicroscope (Olympus SZ61, 50x magnification), and the images were imported into Image-Pro Plus image analysis software. After binarization, the proportion of the total pixel area of ​​continuous veins (linear textures with a length greater than 2mm) to the total pixel area of ​​all veins was calculated, and the average value of the five fields of view was taken as the vein continuity.

[0066] Transmittance: Referencing GB / T 2410-2008 "Determination of Transmittance and Haze of Transparent Plastics," this test characterizes the silky transparency of the coating's vein-like areas. The specific test method involves uniformly spraying the coating onto a 1mm thick quartz glass slide, controlling the dry film thickness to 50±5μm, and drying for 7 days. Areas with a low-density microbubble gel content ≥90% (confirmed using image analysis software) are selected for sampling and testing. This area is primarily composed of mesoporous silicon-titanium bifunctional composite particles with extremely low titanium dioxide content, reflecting the intrinsic transmittance of the vein-like texture. The transmittance is measured using a UV-Vis spectrophotometer (Shimadzu UV-2600) at a wavelength of 550nm. It should be noted that the transmittance test of this invention is carried out in accordance with GB / T 2410-2008 "Determination of transmittance and haze of transparent plastics". This is because the vein area in the coating (mainly low-density microbubble gel) has transparent or semi-transparent characteristics. This method can objectively characterize its silky transparency. The overall coating still maintains a macroscopically opaque stone-like appearance due to the light-blocking effect of titanium dioxide in the high-density base paint.

[0067] Drying time: Test the surface drying time (finger touch method) and the actual drying time (filter paper method) according to GB / T 1728-2020 "Determination of Drying Time of Paint Film".

[0068] Storage stability: The coating was sealed and placed in a 50°C constant temperature chamber for 30 days. The initial viscosity and the viscosity after heat storage were tested using a Brookfield rotational viscometer (4# rotor, 6 rpm), and the viscosity change rate was calculated.

[0069] Abrasion resistance: According to GB / T 1768-2006 "Determination of abrasion resistance of paints and varnishes - Rotary rubber grinding wheel method", the abrasion loss (mg) was tested using a Taber abrasion tester (CS-10 grinding wheel, 1000 g load, 1000 rpm).

[0070] Adhesion: The cross-cut test was conducted in accordance with GB / T 9286-1998 "Cross-cut test for paint and varnish film", and the rating was 0-5.

[0071] Water resistance: In accordance with the HG / T 4847-2025 standard, the sample was immersed in deionized water for 96 hours, and the blistering and peeling of the paint film were observed.

[0072] VOC content: Tested according to GB / T 23986-2009 "Determination of volatile organic compound (VOC) content in paints and varnishes".

[0073] The performance test results are shown in Tables 1 and 2 below: Table 1 Performance test results of Examples 1-5 As shown in Table 1, the texture simulation score of Examples 1-5 is ≥9.0, the vein continuity is ≥90%, and the light transmittance is ≥86%, indicating that the present invention can achieve excellent marble texture effects. Among them, Examples 1 (intermediate ratio) and Examples 5 (upper-middle ratio) performed the best, while Example 2 (lower limit) was slightly lower but still at an excellent level, indicating that the technical solution has broad applicability.

[0074] Table 2 Performance test results of Comparative Examples 1-7 As shown in Table 2, the texture simulation degree, vein continuity, and transmittance of Comparative Example 1 (without CNC) and Comparative Example 2 (without mesoporous silicon-titanium bifunctional composite particles) all decreased significantly, proving that the rheological locking effect of CNC and the optical regulation effect of mesoporous silicon-titanium bifunctional composite particles are indispensable. The texture simulation degree of Comparative Example 3 (without silane-modified magnesium lithium silicate) also decreased, indicating that this component plays an important role in gel strength and texture maintenance. The texture simulation degree of Comparative Example 7 (without electrospinning) dropped to 7.2 points, proving the key role of electrospinning process in texture order.

[0075] Examples 1-5 showed surface drying times ≤20 min and actual drying times ≤4 h, with the drying time slightly decreasing as the amount of crosslinking component increased (Example 3 showed the best results). Comparative Examples 4 (without POSS-hydrazide hybrid lithium magnesium silicate) and 5 (without ADH) showed significantly longer actual drying times, demonstrating that the ketone-hydrazide crosslinking system is the core of rapid drying. Comparative Example 6 (without pH neutralizer) showed an actual drying time extended to 8 h, demonstrating the balancing effect of pH control on drying speed.

[0076] Examples 1-5 show viscosity change rates ≤15%, and the rate decreases with increasing crosslinking components, indicating a good synergistic effect between the POSS-hydrazide hybrid lithium magnesium silicate, ADH, and pH neutralizer in the crosslinking-stabilizing system. Comparative Examples 4-6 show viscosity change rates ≥28%, proving that all three components are indispensable.

[0077] Examples 1-5 showed abrasion loss ≤ 48 mg, adhesion grade 0, and no abnormalities in water resistance; Comparative Examples 4-5 showed abrasion loss ≥ 68 mg and decreased adhesion, demonstrating the enhancing effect of POSS nano-anchors on mechanical properties.

[0078] It should be noted that, for the sake of simplicity, the foregoing embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0079] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add, delete, or otherwise adjust the features of the various embodiments of the present invention according to the circumstances without conflict or creative effort, thereby obtaining different technical solutions that do not fundamentally depart from the concept of the present invention. These technical solutions also fall within the scope of protection of the present invention.

Claims

1. A water-based coating with a marble effect, characterized in that, It consists of component A and component B, with a mass ratio of component A to component B of 7:3-8:2; Component A comprises, by weight, the following: High-density base paint: 300-400 parts of self-crosslinking core-shell structure acrylic emulsion, 2-5 parts of alkyl grafted cellulose nanocrystals, 100-150 parts of titanium dioxide, 10-20 parts of silane-modified magnesium lithium silicate, 1-3 parts of wetting agent, and 150-250 parts of deionized water. Low-density microbubble gel: 100-200 parts of self-crosslinking core-shell structured acrylic emulsion, 30-60 parts of mesoporous silica-titanium bifunctional composite particles, 0.3-0.8 parts of microbubble stabilizer, and 0.5-2 parts of thickener; the density of the low-density microbubble gel is 0.6-0.8 g / cm³. 3 ; The B component comprises, by weight, 100-150 parts of POSS-hydrazide hybrid modified magnesium lithium silicate dispersion, 3-8 parts of adipic acid dihydrazide, 20-40 parts of dipropylene glycol butyl ether, 15-25 parts of isopropanol, 1-3 parts of pH neutralizer, and 50-100 parts of deionized water. The coating is prepared by a microchannel-electrostatic field coupling granulation process, wherein the microchannel size is 0.5-1.0 mm and the electrostatic voltage is 20-30 kV.

2. The water-based coating with a marble effect as described in claim 1, characterized in that, The self-crosslinked core-shell structured acrylic emulsion has a core glass transition temperature of -20°C to -10°C and a shell glass transition temperature of 45°C to 55°C, and the shell contains a ketone carbonyl functional group.

3. The water-based coating with a marble effect as described in claim 1, characterized in that, The preparation method of the self-crosslinked core-shell structured acrylic emulsion includes the following steps: (1) Core layer pre-emulsification: Dissolve 0.3-0.6 parts by weight of anionic emulsifier and 0.6-1.2 parts by weight of nonionic emulsifier in 15-20 parts by weight of deionized water, add 15-20 parts by weight of butyl acrylate, 5-8 parts by weight of methyl methacrylate and 0.5-1.5 parts by weight of glycidyl methacrylate, and emulsify at 1000-1500 rpm for 20-30 minutes to obtain core layer pre-emulsified solution; (2) Shell pre-emulsification: Dissolve 0.15-0.3 parts by weight of anionic emulsifier and 0.3-0.6 parts by weight of nonionic emulsifier in 8-12 parts by weight of deionized water, add 20-25 parts by weight of methyl methacrylate, 3-6 parts by weight of ethyl acrylate, 1-2 parts by weight of diacetone acrylamide and 0.5-1 parts by weight of methacrylic acid, and emulsify at 1000-1500 rpm for 20-30 minutes to obtain shell pre-emulsion; (3) Seed polymerization: At 75-85℃, add 5-15% of the total amount of the core layer pre-emulsion and 0.1-0.2 parts by weight of ammonium persulfate, and keep the reaction at the temperature for 20-40 minutes to form seeds; (4) Core layer polymerization: At 80-85℃, the remaining core layer pre-emulsion and 0.1-0.2 parts by weight of ammonium persulfate solution are added dropwise over 2-3 hours, and the mixture is kept warm for 0.5-1.5 hours. (5) Shell polymerization: Add shell pre-emulsion and 0.05-0.15 parts by weight of ammonium persulfate solution dropwise at 80-85℃, complete the addition in 1.5-2.5 hours, and keep warm for 1.5-2.5 hours; (6) Post-treatment: Cooling and filtration to obtain a self-crosslinked core-shell acrylic emulsion with a solid content of 45±1%.

4. The water-based coating with a marble effect as described in claim 1, characterized in that, The preparation method of the alkyl-grafted cellulose nanocrystals includes the following steps: (1) Dispersion: Add 1 part by weight of cellulose nanocrystals to 15-25 parts by weight of N,N-dimethylformamide and disperse by ultrasonication for 20-40 minutes; (2) Grafting reaction: Add 0.1-0.3 parts by weight of pyridine, slowly add 0.4-0.8 parts by weight of C12-C16 long-chain alkyl acyl chloride, and react at 60-80℃ for 4-8 hours; (3) Washing and separation: After the reaction is completed, add 50-80 parts by weight of anhydrous ethanol to precipitate, centrifuge and then wash with anhydrous ethanol and deionized water 2-3 times each. (4) Drying: Vacuum drying at 45-55℃ for 20-28 hours to obtain alkyl-grafted cellulose nanocrystals with an alkyl grafting rate of 5-15%.

5. The water-based coating with a marble effect as described in claim 1, characterized in that, The mesoporous silicon-titanium bifunctional composite particles are prepared by a method comprising the following steps: (1) Preparation of amino-modified silica particles: Dissolve 1-1.5 parts by weight of tetraethyl orthosilicate in 5-8 parts by weight of anhydrous ethanol, and slowly drop it into 10-15 parts by weight of an aqueous ethanol solution containing 0.8-1.2 parts by weight of ammonia. React at 25-35°C for 10-14 hours. After modification with aminopropyltrimethoxysilane, amino-modified silica particles are obtained. (2) Disperse amino-modified silica particles in 4-6 parts by weight of melted paraffin, add 25-35 parts by weight of deionized water, emulsify at 75-85℃ and 800-1200rpm for 0.5-1.5 hours to form a Pickering emulsion, and then cool and solidify to obtain the product; (3) Selectively grow titanium dioxide on the surface of the colloidal body, wash it by centrifugation, remove the paraffin template with 50-100 parts by weight of cyclohexane, and calcine at 400-500℃ for 2-4 hours to obtain mesoporous silicon-titanium bifunctional composite particles.

6. The water-based coating with a marble effect as described in claim 1, characterized in that, The preparation method of the POSS-hydrazide hybrid modified lithium magnesium silicate dispersion is as follows: add lithium magnesium silicate to 35-45 parts by weight of deionized water, stir and peel at 1000-1200 rpm for 24-48 hours, mix the lithium magnesium silicate dispersion with amino POSS and adipic dihydrazide at a mass ratio of 100:(2-5):(3-8), add 0.5-1.0% by weight of glutaraldehyde of lithium magnesium silicate, react at 50-70℃ for 6-10 hours, spray dry, and then disperse in deionized water to prepare a dispersion with a solid content of 8-12%.

7. The water-based coating with marble effect as described in claim 1, characterized in that, The wetting agent is a nonionic wetting agent; the microbubble stabilizer is sodium dodecyl sulfate; the thickener is an alkali-swellable acrylic thickener; and the pH neutralizer is AMP-95 or ammonia.

8. A method for preparing a water-based marble effect coating according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Preparation of high-density base paint: Dissolve alkyl grafted cellulose nanocrystals in deionized water, add self-crosslinked core-shell structure acrylic emulsion, titanium dioxide, silane-modified magnesium lithium silicate, and wetting agent, and disperse at 800-1000 rpm for 30-40 minutes; (2) Preparation of low-density microbubble gel: Mix self-crosslinked core-shell structured acrylic emulsion, mesoporous silica-titanium bifunctional composite particles, microbubble stabilizer, and thickener, stir at 200-400 rpm, and microbubble until the density is 0.6-0.8 g / cm³. 3 ; (3) Microchannel pre-stacked sheets: High-density base paint and low-density microbubble gel are fed into a 0.5-1.0mm microchannel mixer at a ratio of 7:3-8:2 to form laminar flow stacked micro-clusters; (4) Preparation of component B: POSS-hydrazide hybrid modified magnesium lithium silicate dispersion, adipic acid dihydrazide, dipropylene glycol butyl ether, isopropanol, pH neutralizer and deionized water are mixed and stirred at 400-600 rpm for 20-30 minutes. (5) Electrospinning atomization granulation: The laminar flow stacked micro-particles are conveyed to the electrospinning atomization nozzle and atomized under a voltage of 20-30kV. At the same time, component B is conveyed to the nozzle and mixed with the micro-particles, and sprayed onto the surface of the substrate to form a marble texture coating.

9. The method for preparing the water-based coating with marble effect as described in claim 8, characterized in that, The airflow pressure for electrospinning atomization in step (5) is 0.2-0.4 MPa.

10. The method for preparing the water-based coating with marble effect as described in claim 8, characterized in that, In step (5), the sprayed film thickness is 150-200μm, the surface drying time is ≤20 minutes, the actual drying time is ≤4 hours, and the recoating interval is ≤2 hours.

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