Environment-friendly water-based paint and preparation method thereof

Abstract

The application discloses an environment-friendly water-based paint and a preparation method thereof. The paint comprises, by mass fraction, 30-50 parts of a bio-based modified acrylic emulsion, 5-10 parts of a lignin sulfonate, 3-8 parts of a gas-phase flame retardant, 2-5 parts of a liquid-phase smoke suppressant, 5-10 parts of a temperature-sensitive microcapsule flame retardant, 1-3 parts of a temperature-sensitive color-changing material and 2-5 parts of an auxiliary agent. The paint realizes a 32-40% reduction in the thermal conductivity of a carbonized layer, a 52-60% reduction in smoke density, a 6-9-second color change early warning, a 20-28 g / L VOC content and a 1st grade adhesion by means of lignin modified emulsion, gas-liquid phase synergistic smoke suppression and microcapsule targeted release, and has excellent fireproof, smoke suppression and environmental protection performances. The preparation method comprises emulsion polymerization, microcapsule preparation, component mixing, pH and viscosity adjustment and filtration, is simple in process and suitable for industrialized production, and is suitable for high-safety scenes such as buildings and furniture.

Description

Technical Field

[0001] This invention relates to the technical field of environmentally friendly water-based coatings, and in particular to an environmentally friendly water-based coating and its preparation method. Background Technology

[0002] Waterborne coatings, as an environmentally friendly coating material using water as the dispersion medium, have been widely used in construction, furniture, automotive, and industrial corrosion protection due to their low volatile organic compound (VOC) emissions, convenient application, and environmentally friendly characteristics. In recent years, with increasingly stringent environmental regulations and the popularization of green building concepts, the research and development focus of waterborne coatings has gradually shifted from basic performance optimization to functional enhancement, particularly improved fire resistance. Traditional waterborne fire-retardant coatings mostly employ intumescent flame-retardant systems, using components such as ammonium polyphosphate, pentaerythritol, and melamine to form a charred layer at high temperatures to achieve heat insulation and flame retardant effects. Technological advancements also include the introduction of nanomaterials, such as nano-silanes or montmorillonite, to enhance the mechanical strength and thermal stability of the coating film. Furthermore, some research has explored bio-based flame retardants (such as modified lignin) and microencapsulation technology to improve the environmental friendliness of coatings and the stability of flame retardants. These technological developments have driven significant progress in the fire resistance time and film performance of waterborne fire-retardant coatings, providing reliable solutions for multi-substrate applications. However, existing technologies still face many challenges in practical applications, especially in terms of overall performance in complex fire scenarios.

[0003] Despite this, existing water-based fire-retardant coatings have significant shortcomings in smoke suppression and long-term durability, limiting their application in scenarios with high safety requirements. First, traditional intumescent flame-retardant systems easily generate large amounts of smoke during combustion, primarily due to volatile organic compounds (VOCs) produced by the pyrolysis of the base resin (such as acrylic emulsions) and gaseous byproducts released from the decomposition of flame retardants. This smoke not only reduces visibility and hinders fire escape but may also release toxic gases, posing a threat to the environment and human health. Second, existing smoke suppression technologies often rely on additives such as metal oxides (such as zinc oxide) or hydrotalcite, but these components have poor compatibility with water-based matrices, easily leading to a decline in the mechanical properties of the coating film or flame retardant migration, thereby weakening the long-term fire-retardant effect. Furthermore, traditional flame retardants have high trigger temperatures, making it difficult to quickly form an effective char layer in the early stages of a fire, limiting early fire protection and smoke suppression capabilities. Summary of the Invention

[0004] This application provides an environmentally friendly water-based coating, comprising, by weight parts: 30 to 50 parts of water-based acrylic emulsion, 5 to 10 parts of bio-based flame retardant monomer modifier, 3 to 8 parts of gas-phase flame retardant, 2 to 5 parts of liquid-phase smoke suppressant, 5 to 10 parts of thermosensitive microcapsule flame retardant, 1 to 3 parts of thermochromic material, and 2 to 5 parts of additives.

[0005] Preferably, the gas-phase flame retardant is triphenyl phosphate or diphenyl octyl phosphate.

[0006] Preferably, the liquid-phase smoke suppressant is modified hydrotalcite.

[0007] Preferably, the thermochromic material is dimethylglyoxime nickel(II).

[0008] Preferably, the additives include dispersants, defoamers, leveling agents, and thickeners.

[0009] Preferably, the dispersant is sodium polyacrylate, the defoamer is polydimethylsiloxane, the leveling agent is polyether-modified polysiloxane, and the thickener is hydroxyethyl cellulose.

[0010] A method for preparing an environmentally friendly water-based coating includes the following technical steps:

[0011] Step 1. Add the bio-based modified acrylic emulsion, gas phase flame retardant, liquid phase smoke suppressant, thermosensitive microcapsule, thermochromic material and additives to the mixing tank according to the formula ratio, and stir at 200-300 rpm for 30-60 minutes.

[0012] Step 2. Adjust the pH of the coating to 7-8 using a pH adjuster, and add a thickener to adjust the viscosity to 1000-3000 mPa·s; wherein the pH adjuster is ammonia or citric acid.

[0013] Preferably, the preparation steps of the bio-based modified acrylic emulsion include:

[0014] Lignosulfonate and acrylic monomer are mixed at a mass ratio of 1:10 to 1:5, sodium dodecyl sulfate and potassium persulfate are added, and emulsion polymerization is carried out at 70-80℃ with a stirring speed of 300-400 rpm for 4-6 hours. After cooling to room temperature, a bio-based modified acrylic emulsion is obtained.

[0015] Preferably, the temperature-sensitive microcapsule flame retardant comprises:

[0016] Triphenyl phosphate was mixed with cyclohexane, and sorbitan monooleate was added to form an oil phase. PNIPAM monomer and N,N'-methylenebisacrylamide were dissolved in the aqueous phase, and ammonium persulfate was added. The oil phase was slowly added to the aqueous phase at 40-50°C, with a stirring speed of 500-600 rpm and a polymerization time of 2-3 hours. The mixture was then filtered, washed, and dried to obtain temperature-sensitive microcapsules.

[0017] The environmentally friendly water-based coating provided by this invention exhibits significant beneficial effects through a synergistic formulation of bio-based modified acrylic emulsion (30-50 parts), lignin sulfonate (5-10 parts), gas-phase flame retardant (3-8 parts), liquid-phase smoke suppressant (2-5 parts), thermosensitive microcapsule flame retardant (5-10 parts), and thermochromic material (1-3 parts): the thermal conductivity of the carbonized layer is reduced by 32-40%, forming a dense heat insulation layer and effectively improving fire resistance; the smoke density is reduced by 52-60%, significantly reducing smoke and toxic gas emissions through gas-liquid phase synergistic smoke suppression and low-temperature release of flame retardant from microcapsules; the color-changing warning time is 6-9 seconds, providing early visual warning of fire and enhancing safety; the VOC content is as low as 20-28 g / L, far below the national standard (≤120 g / L), demonstrating excellent environmental protection; the adhesion is Grade 1, the coating film is firm, and the water resistance is strong (no change after ≥96 hours), making it suitable for various substrates and complex scenarios. Compared to the control example (carbonized layer thermal conductivity reduced by 18-20%, smoke density reduced by 30-33%, VOC 35-37g / L, adhesion level 2), this invention solves the problems of large smoke volume, insufficient early fire protection and poor environmental performance of traditional water-based fireproof coatings. The process is simple, suitable for industrial production, and applicable to high-safety scenarios such as construction and furniture. Detailed Implementation

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0019] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0020] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0021] Example

[0022] Example 1

[0023] Formula (parts by weight):

[0024] Bio-based modified acrylic emulsion (bio-based modified): 40 parts

[0025] Gas phase flame retardant (triphenyl phosphate): 4 parts

[0026] Liquid phase smoke suppressant (modified hydrotalcite): 3 parts

[0027] Thermosensitive microcapsule flame retardant: 7 parts

[0028] Thermochromic material (dimethylglyoxime nickel(II)): 2 parts

[0029] Additives: 3 parts (sodium polyacrylate 0.8 parts, polydimethylsiloxane 0.3 parts, polyether-modified polysiloxane 0.5 parts, hydroxyethyl cellulose 0.4 parts)

[0030] Water: Balance

[0031] Preparation method:

[0032] Step 1. Preparation of bio-based modified acrylic emulsion: Lignosulfonate and acrylic monomer are mixed at a mass ratio of 1:8, 1.5wt% sodium dodecyl sulfate (emulsifier) ​​and 0.8wt% potassium persulfate (initiator) are added, emulsion polymerization is carried out at 75°C with a stirring speed of 350 rpm for 5 hours, and then cooled to room temperature to obtain bio-based modified acrylic emulsion.

[0033] Step 2. Preparation of temperature-sensitive microcapsule flame retardant: Triphenyl phosphate and cyclohexane were mixed at a mass ratio of 1:3 and heated to 50°C to completely dissolve the triphenyl phosphate. 2.5 wt% sorbitan monooleate (Span 80) was added to form an oil phase. N-isopropylacrylamide (NIPAM) monomer and N,N'-methylenebisacrylamide (MBA, accounting for 7 wt% of NIPAM) were dissolved in deionized water (NIPAM concentration 3 wt%). 1.5 wt% ammonium persulfate (APS) was added as an initiator to form an aqueous phase. At 45°C, the oil phase was slowly added dropwise to the aqueous phase at a rate of 1.5 mL / min, with a stirring speed of 550 rpm. Polymerization was carried out for 2.5 hours. The microcapsules were separated by centrifugation (3000 rpm, 5 minutes), washed three times with ethanol and deionized water (volume ratio 1:1), and vacuum dried at 50°C for 12 hours to obtain temperature-sensitive microcapsules with a particle size of 10-30 μm.

[0034] Step 3. Mixing components: Add the bio-based modified acrylic emulsion, triphenyl phosphate, modified hydrotalcite, thermosensitive microcapsules, dimethylglyoxime nickel(II) and additives to the mixing tank according to the formula ratio, and stir at 250 rpm for 45 minutes to ensure uniform dispersion.

[0035] Step 4. Adjust pH and viscosity: Use ammonia to adjust the pH of the coating to 7.5, and add hydroxyethyl cellulose to adjust the viscosity to 2000 mPa·s.

[0036] Step 5. Filtering and Packaging: Filter through a 200-mesh filter to remove impurities, seal in packaging, and store away from light.

[0037] Example 2

[0038] Formula (parts by weight):

[0039] Bio-based modified acrylic emulsion (bio-based modified): 45 parts

[0040] Vapor phase flame retardant (diphenyl octyl phosphate): 5 parts

[0041] Liquid smoke suppressant: 2.5 parts

[0042] Temperature-sensitive microcapsule flame retardant: 8 parts

[0043] Thermochromic material: 1.5 parts

[0044] Additives: 3.5 parts

[0045] Water: Balance

[0046] Preparation method:

[0047] Preparation method:

[0048] Step 1. Preparation of bio-based modified acrylic emulsion: Lignosulfonate and acrylic monomer are mixed at a mass ratio of 1:10, 1.2wt% sodium dodecyl sulfate and 0.7wt% potassium persulfate are added, and emulsion polymerization is carried out at 78°C with a stirring speed of 380 rpm for 5.5 hours. After cooling to room temperature, bio-based modified acrylic emulsion is obtained.

[0049] Step 2. Preparation of temperature-sensitive microcapsule flame retardant: Diphenyl octyl phosphate and cyclohexane were mixed at a mass ratio of 1:3 and heated to 50°C to dissolve. 2.8 wt% sorbitan monooleate was added to form an oil phase. NIPAM and MBA (8 wt% of NIPAM) were dissolved in deionized water (NIPAM concentration 3.5 wt%), and 1.8 wt% ammonium persulfate was added to form an aqueous phase. At 48°C, the oil phase was added dropwise to the aqueous phase at 1.8 mL / min, with stirring at 580 rpm, and polymerization was carried out for 2.8 hours. The mixture was centrifuged, washed three times with ethanol and deionized water (1:1), and vacuum dried at 50°C for 12 hours to obtain temperature-sensitive microcapsules with a particle size of 10-30 μm.

[0050] Step 3. Mixing components: Add the bio-based modified acrylic emulsion, diphenyl octyl phosphate, modified hydrotalcite, thermosensitive microcapsules, dimethylglyoxime nickel(II) and additives to the mixing tank according to the formula ratio, and stir at 280 rpm for 50 minutes.

[0051] Step 4. Adjust pH and viscosity: Use ammonia to adjust the pH of the coating to 7.8, and add hydroxyethyl cellulose to adjust the viscosity to 2200 mPa·s.

[0052] Step 5. Filtering and Packaging: Filter through a 200-mesh filter, seal in packaging, and store away from light.

[0053] Example 3

[0054] Formula (parts by weight):

[0055] Bio-based modified acrylic emulsion (bio-based modified): 35 parts

[0056] Gas phase flame retardant (triphenyl phosphate): 3 parts

[0057] Liquid phase smoke suppressant (modified hydrotalcite): 4 parts

[0058] Thermosensitive microcapsule flame retardant: 6 parts

[0059] Thermochromic material (dimethylglyoxime nickel(II)): 2.5 parts

[0060] Additives: 2.5 parts (sodium polyacrylate 0.7 parts, polydimethylsiloxane 0.3 parts, polyether-modified polysiloxane 0.4 parts, hydroxyethyl cellulose 0.3 parts)

[0061] Water: Balance

[0062] Preparation method:

[0063] Step 1. Preparation of bio-based modified acrylic emulsion: Lignosulfonate and acrylic monomer are mixed at a mass ratio of 1:5, 1.8wt% sodium dodecyl sulfate and 1.0wt% potassium persulfate are added, and emulsion polymerization is carried out at 72℃ with a stirring speed of 320rpm for 4.5 hours. After cooling to room temperature, bio-based modified acrylic emulsion is obtained.

[0064] Step 2. Preparation of temperature-sensitive microcapsule flame retardant: Triphenyl phosphate and cyclohexane were mixed at a mass ratio of 1:3 and heated to 50°C to dissolve. 2.3 wt% sorbitan monooleate was added to form an oil phase. NIPAM and MBA (6 wt% of NIPAM) were dissolved in deionized water (NIPAM concentration 2.5 wt%), and 1.2 wt% ammonium persulfate was added to form an aqueous phase. At 42°C, the oil phase was added dropwise to the aqueous phase at 1.2 mL / min, with stirring at 520 rpm for 2.3 hours. After centrifugation, the microcapsules were washed three times with ethanol and deionized water (1:1), and then vacuum dried at 50°C for 12 hours to obtain temperature-sensitive microcapsules with a particle size of 10-30 μm.

[0065] Step 3. Mixing components: Add the bio-based modified acrylic emulsion, triphenyl phosphate, modified hydrotalcite, thermosensitive microcapsules, dimethylglyoxime nickel(II) and additives to the mixing tank according to the formula ratio, and stir at 220 rpm for 40 minutes.

[0066] Step 4. Adjust pH and viscosity: Use citric acid to adjust the pH of the coating to 7.2, and add hydroxyethyl cellulose to adjust the viscosity to 1800 mPa·s.

[0067] Step 5. Filtering and Packaging: Filter through a 200-mesh filter, seal in packaging, and store away from light.

[0068] Example 4

[0069] Formula (parts by weight):

[0070] Bio-based modified acrylic emulsion (bio-based modified): 50 parts

[0071] Vapor phase flame retardant (diphenyl octyl phosphate): 6 parts

[0072] Liquid-phase smoke suppressant (modified hydrotalcite): 3.5 parts

[0073] Thermosensitive microcapsule flame retardant: 10 parts

[0074] Thermochromic material (dimethylglyoxime nickel(II)): 1 part

[0075] Additives: 4 parts (sodium polyacrylate 1.2 parts, polydimethylsiloxane 0.5 parts, polyether-modified polysiloxane 0.7 parts, hydroxyethyl cellulose 0.6 parts)

[0076] Water: Balance

[0077] Preparation method:

[0078] Step 1. Preparation of bio-based modified acrylic emulsion: Lignosulfonate and acrylic monomer are mixed at a mass ratio of 1:10, 1.3wt% sodium dodecyl sulfate and 0.6wt% potassium persulfate are added, and emulsion polymerization is carried out at 80℃ with a stirring speed of 400rpm for 6 hours. After cooling to room temperature, bio-based modified acrylic emulsion is obtained.

[0079] Step 2. Preparation of temperature-sensitive microcapsule flame retardant: Diphenyl octyl phosphate and cyclohexane were mixed at a mass ratio of 1:3 and heated to 50°C to dissolve. 3.0 wt% sorbitan monooleate was added to form an oil phase. NIPAM and MBA (8 wt% of NIPAM) were dissolved in deionized water (4 wt% NIPAM concentration). 2.0 wt% ammonium persulfate was added to form an aqueous phase. At 50°C, the oil phase was added dropwise to the aqueous phase at 2.0 mL / min. The mixture was stirred at 600 rpm and polymerized for 3 hours. After centrifugation, the mixture was washed three times with ethanol and deionized water (1:1). The mixture was then vacuum dried at 50°C for 12 hours to obtain temperature-sensitive microcapsules with a particle size of 10-30 μm.

[0080] Step 3. Mixing components: Add the bio-based modified acrylic emulsion, diphenyl octyl phosphate, modified hydrotalcite, thermosensitive microcapsules, dimethylglyoxime nickel(II) and additives to the mixing tank according to the formula ratio, and stir at 300 rpm for 60 minutes.

[0081] Step 4. Adjust pH and viscosity: Use ammonia to adjust the pH of the coating to 8.0, and add hydroxyethyl cellulose to adjust the viscosity to 2500 mPa·s.

[0082] Step 5. Filtering and Packaging: Filter through a 200-mesh filter, seal in packaging, and store away from light.

[0083] Comparison Example

[0084] Control Example 1 (using conventional acrylic emulsion, without bio-based modification)

[0085] Formula (parts by weight):

[0086] Aqueous acrylic emulsion (conventional, unmodified): 40 parts

[0087] Gas phase flame retardant (triphenyl phosphate): 4 parts

[0088] Liquid phase smoke suppressant (modified hydrotalcite): 3 parts

[0089] Thermosensitive microcapsule flame retardant: 7 parts

[0090] Thermochromic material (dimethylglyoxime nickel(II)): 2 parts

[0091] Additives: 3 parts (same as in Example 1)

[0092] Water: Balance

[0093] Preparation method:

[0094] Use conventional aqueous acrylic emulsion (solid content 40-50wt%, without lignin sulfonate modification).

[0095] Preparation of temperature-sensitive microcapsules: Same as in Example 1.

[0096] Mixing components: 250 rpm, 45 minutes.

[0097] Adjust the pH to 7.5 with ammonia and adjust the viscosity to 2000 mPa·s with hydroxyethyl cellulose.

[0098] 200-mesh filter, sealed packaging.

[0099] Comparative Example 2 (using conventional flame-retardant monomers instead of bio-based modifiers)

[0100] Formula (parts by weight):

[0101] Aqueous acrylic emulsion (modified with phosphate ester monomers): 40 parts

[0102] Gas phase flame retardant (triphenyl phosphate): 4 parts

[0103] Liquid phase smoke suppressant (modified hydrotalcite): 3 parts

[0104] Thermosensitive microcapsule flame retardant: 7 parts

[0105] Thermochromic material (dimethylglyoxime nickel(II)): 2 parts

[0106] Additives: 3 parts (same as in Example 1)

[0107] Water: Balance

[0108] Preparation method:

[0109] Preparation of modified acrylic emulsion: Replace lignin sulfonate with phosphate monomer (phosphate methacrylate), mix with acrylic monomer at a ratio of 1:8, 75℃, 350 rpm, for 5 hours.

[0110] Preparation of temperature-sensitive microcapsules: Same as in Example 1.

[0111] Mixing components: 250 rpm, 45 minutes.

[0112] Adjust the pH to 7.5 with ammonia and adjust the viscosity to 2000 mPa·s with hydroxyethyl cellulose.

[0113] 200-mesh filter, sealed packaging

[0114] Performance testing methods

[0115] 1. Thermal conductivity of the carbonized layer

[0116] Test method:

[0117] Equipment: Thermal conductivity meter (such as Netzsch LFA 467 laser flash thermal conductivity meter).

[0118] Sample preparation: The coating was applied to a standard steel plate (100mm×100mm×1mm) with a film thickness of 100-150μm and dried for 24 hours. The sample was then heated in a muffle furnace at 600℃ for 10 minutes to form a carbonized layer.

[0119] Test steps:

[0120] The carbonized layer sample was placed in a thermal conductivity meter, the temperature was set to 25℃, and the sample thickness was tested.

[0121] Thermal conductivity was measured using the laser flash method, and the initial thermal conductivity and the reduction in thermal conductivity compared to a standard carbonized layer (unmodified coating) were recorded.

[0122] Repeat the test 3 times and take the average value.

[0123] Standard: Refer to ASTM E1461 (Standard for testing thermal diffusivity and thermal conductivity).

[0124] 2. Smoke density

[0125] Test method:

[0126] Equipment: Smoke density tester (such as NBS smoke density box, conforming to GB / T 8627).

[0127] Sample preparation: The coating was applied to an asbestos-free fiber cement board (150mm×150mm×5mm) with a film thickness of 100μm and dried for 48 hours.

[0128] Test steps:

[0129] The sample was placed in a smoke density chamber and a standard flame combustion mode (25kW / m³) was used. 2 Radiative heat flow.

[0130] Record the light flux decay over 4 minutes of combustion and calculate the smoke density (Ds, maximum smoke density value).

[0131] The percentage reduction in smoke density was calculated compared to standard water-based coatings (without smoke suppressants).

[0132] Repeat the test 3 times and take the average value.

[0133] Standard: Refer to GB / T 8627-2007 (Test method for smoke density of building materials during combustion or decomposition).

[0134] 3. Color-changing warning time

[0135] Test method:

[0136] Equipment: constant temperature heating table, stopwatch, high-definition camera.

[0137] Sample preparation: The coating was applied to a glass substrate (50mm×50mm) with a film thickness of 100μm and dried for 24 hours.

[0138] Test steps:

[0139] Place the sample on a constant temperature heating stage and set the temperature to 100℃.

[0140] The time from the start of heating to the appearance of a distinct red color was recorded using a high-definition camera (based on the color change of dimethylglyoxime nickel(II)).

[0141] Repeat the test 5 times and take the average value.

[0142] Standard: Referencing ISO 5660 (Reactive Flame Test Standard), combined with the characteristics of thermochromic materials.

[0143] 4. Volatile Organic Compound (VOC) Content

[0144] Test method:

[0145] Equipment: Gas chromatography-mass spectrometry (GC-MS, such as Agilent 7890B / 5977B).

[0146] Sample preparation: Take 5g of paint sample and seal it in a sampling bottle.

[0147] Test steps:

[0148] Using headspace sampling, the sample was heated to 80°C and equilibrated for 30 minutes.

[0149] Volatile organic compounds (VOCs) were analyzed by GC-MS, and major VOC components such as toluene, xylene, and ethyl acetate were quantitatively detected.

[0150] Calculate the total VOC content (unit: g / L).

[0151] Repeat the test 3 times and take the average value.

[0152] Standard: Refer to GB 18582-2020 (VOC Limit Standard for Interior Decoration and Renovation Materials).

[0153] 5. Adhesion

[0154] Test method:

[0155] Equipment: Cross-cut tester, 3M tape.

[0156] Sample preparation: The coating was applied to a steel plate (100mm×50mm×1mm) with a film thickness of 100μm and dried for 48 hours.

[0157] Test steps:

[0158] Use a cross-cut tester to cut a 6×6 1mm grid on the coating surface.

[0159] Apply 3M tape to the marked area, quickly peel it off, and observe the coating peeling.

[0160] Rating based on the degree of peeling (0 being the best, 5 being the worst).

[0161] Repeat the test 3 times and take the average value.

[0162] Standard: Refer to GB / T 9286-2021 (Cross-cut test for paints and varnishes).

[0163] Table 1

[0164]

[0165]

[0166] Based on Examples 1 to 4 and Table 1, it can be analyzed that the thermal conductivity of the charred layer is reduced by 32-40%, the smoke density is reduced by 52-60%, the color change warning time is 6-9 seconds, the VOC content is 20-28 g / L, and the adhesion is all at Grade 1, demonstrating excellent fire resistance, smoke suppression, warning, and environmental protection performance. The examples, through the integration of lignin sulfonate modified emulsion, targeted release of thermosensitive microcapsules, gas-liquid phase synergistic smoke suppression (phosphate ester + modified hydrotalcite), and thermosensitive color change technology, significantly improve fire resistance, smoke suppression, and environmental protection performance, surpassing conventional emulsions and traditional flame-retardant monomers, and solving the problems of large smoke volume and insufficient early fire protection.

[0167] Based on the analysis of Example 1, Comparative Example 1, and Table 1, Example 1 is significantly superior to Comparative Example 1 in terms of reduced thermal conductivity of the charred layer (35% vs. 18%), reduced smoke density (55% vs. 30%), VOC content (25 g / L vs. 35 g / L), and adhesion (Grade 1 vs. Grade 2). The color change warning time is 8 seconds for both examples. Example 1 uses lignin sulfonate modified acrylic emulsion (40 parts, 1:8), which promotes the formation of a dense charred layer through hydroxyl and sulfonic acid groups, reducing thermal conductivity and VOCs. The gas-phase flame retardant (triphenyl phosphate, 4 parts), liquid-phase smoke suppressant (modified hydrotalcite, 3 parts), and temperature-sensitive microcapsules (7 parts) work synergistically to capture free radicals, adsorb volatiles, and release the flame retardant at low temperatures, significantly improving the smoke suppression effect. The hydrophilic groups and additives optimize the coating interface and enhance adhesion. Compared with Example 1, which uses a conventional emulsion, the lack of flame-retardant groups, loose carbonized layer, high volatile content, and poor compatibility resulted in insufficient performance, highlighting the innovation of Example 1 in fire prevention, smoke suppression, and environmental protection.

[0168] Based on the analysis of Example 1, Comparative Example 2, and Table 1, it can be seen that Example 1 is significantly superior to Comparative Example 2 in terms of reduced thermal conductivity of the carbonized layer (35% vs. 20%), reduced smoke density (55% vs. 33%), VOC content (25 g / L vs. 37 g / L), and adhesion (Grade 1 vs. Grade 2). The color change warning time is 8 seconds for both examples, showing that Example 1 has obvious advantages in fire prevention, smoke suppression, and environmental protection performance. Example 1 uses a lignin sulfonate-modified acrylic emulsion (40 parts, 1:8). The hydroxyl and sulfonic acid groups promote the formation of a dense char layer at high temperatures, reducing thermal conductivity and VOCs. A gas-phase flame retardant (triphenyl phosphate, 4 parts), a liquid-phase smoke suppressant (modified hydrotalcite, 3 parts), and temperature-sensitive microcapsules (7 parts) work synergistically to achieve highly efficient smoke suppression (55%) through gas-phase free radical capture, liquid-phase volatile adsorption, and low-temperature targeted release of the flame retardant. The hydrophilic groups of lignin and the additives optimize the coating interface, achieving an adhesion grade of 1. In contrast, Example 2 uses a phosphate monomer (phosphate methacrylate)-modified emulsion. The flame-retardant effect is limited, the char layer is looser, and volatile byproducts increase (VOC 37 g / L). The poor synergy with hydrotalcite results in insufficient smoke suppression (33%) and adhesion (grade 2), highlighting the innovation of Example 1 through bio-based modification and a synergistic system.

[0169] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An environmentally friendly water-based coating, characterized in that, The product comprises, by weight, 30 to 50 parts of bio-based modified acrylic emulsion, 3 to 8 parts of vapor phase flame retardant, 2 to 5 parts of liquid phase smoke suppressant, 5 to 10 parts of thermosensitive microcapsule flame retardant, 1 to 3 parts of thermochromic material, and 2 to 5 parts of additives. The gas-phase flame retardant is triphenyl phosphate or diphenyl octyl phosphate; The liquid-phase smoke suppressant is modified hydrotalcite; The thermochromic material is dimethylglyoxime nickel, wherein the nickel is divalent. The preparation steps of the bio-based modified acrylic emulsion include: Lignosulfonate and acrylic monomer are mixed at a mass ratio of 1:10 to 1:5, sodium dodecyl sulfate and potassium persulfate are added, and emulsion polymerization is carried out at 70-80℃ with a stirring speed of 300-400 rpm for 4-6 hours. After cooling to room temperature, a bio-based modified acrylic emulsion is obtained. The temperature-sensitive microcapsule flame retardant includes: Triphenyl phosphate was mixed with cyclohexane, and sorbitan monooleate was added to form an oil phase. PNIPAM monomer and N,N'-methylenebisacrylamide were dissolved in the aqueous phase, and ammonium persulfate was added. The oil phase was slowly added to the aqueous phase at 40-50°C, with a stirring speed of 500-600 rpm and a polymerization time of 2-3 hours. The mixture was then filtered, washed, and dried to obtain temperature-sensitive microcapsules.

2. The environmentally friendly water-based coating according to claim 1, characterized in that, The additives include dispersants, defoamers, leveling agents, and thickeners.

3. The environmentally friendly water-based coating according to claim 2, characterized in that, The dispersant is sodium polyacrylate, the defoamer is polydimethylsiloxane, the leveling agent is polyether-modified polysiloxane, and the thickener is hydroxyethyl cellulose.

4. The preparation method of the environmentally friendly water-based coating according to claim 1 includes the following technical steps: Step 1. Add the bio-based modified acrylic emulsion, vapor-phase flame retardant, liquid-phase smoke suppressant, thermosensitive microcapsules, thermochromic material, and additives to a mixing tank according to the formula ratio, and stir at 200-300 rpm for 30-60 minutes; Step 2. Adjust the pH of the coating to 7-8 using a pH adjuster, and add a thickener to adjust the viscosity to 1000-3000 mPa·s; The pH adjuster is ammonia or citric acid.

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