Flame-retardant antistatic polymer coating material for dust-free workshop floor

Abstract

The present application relates to the field of functional polymer coating materials, and discloses a kind of high polymer coating materials for fire-retardant antistatic dust-free workshop floor, which uses silicon modified epoxy acrylate as matrix, the core is to introduce a kind of polymerizable functional phosphorus-based imidazole ionic liquid monomer, the monomer integrates phosphorus-based flame-retardant group and imidazole-based antistatic group in molecule, and is covalently bonded with polymer network through vinyl group.The present application significantly improves the flame-retardant performance, the durability of antistatic function, the overall physical and mechanical strength, the chemical resistance and the uniformity of surface performance of floor coating through the in-situ polymerization of functional components and the synergistic optimization of conductive network, effectively overcomes the defects that the functions of traditional floor materials are easy to decay and the comprehensive performance is difficult to meet the special environmental requirements of dust-free workshop.

Description

Technical Field

[0001] This invention relates to the field of functional polymer coating materials technology, specifically a flame-retardant and antistatic polymer coating material for cleanroom flooring. Background Technology

[0002] With the rapid development of modern industrial technology, especially in high-tech industries such as electronics, semiconductors, precision instruments, biopharmaceuticals, and aerospace, increasingly stringent requirements have been placed on the cleanliness, safety, and stability of production environments. Cleanrooms, as key infrastructure for ensuring product quality and production efficiency in these industries, require crucial internal environmental control. Flooring, as the largest component in a cleanroom, directly impacts the overall environmental quality. Traditional industrial flooring coatings often fail to fully meet the comprehensive needs of cleanrooms for low dust generation, wear resistance, chemical corrosion resistance, and special functions (such as antistatic and flame retardancy).

[0003] In cleanrooms, the accumulation and uncontrolled release of static charge pose significant risks, including damage to electronic components, malfunctions in precision equipment, and even fires and explosions. Therefore, excellent and durable antistatic properties are essential for flooring materials. Current technologies typically employ the addition of conductive fillers (such as carbon-based materials, metal powders, or fibers) or small-molecule antistatic agents (such as quaternary ammonium salts, surfactants, and certain ionic liquids) to impart antistatic properties to floor coatings. However, excessive amounts of conductive fillers can negatively impact the mechanical properties and workability of the coating, and uneven dispersion can lead to unstable antistatic performance. Small-molecule antistatic agents, due to poor compatibility with the polymer matrix or their existence through physical adsorption, are prone to migration, seepage, and loss during long-term use, cleaning, or friction, resulting in a gradual decline or even loss of antistatic effects, failing to meet the durable functional requirements of cleanroom flooring.

[0004] Meanwhile, cleanrooms typically store large quantities of precision electronic equipment and flammable chemicals, placing high demands on the flame-retardant properties of flooring materials. This is crucial to effectively slow the spread of fire in the event of a fire, buying valuable time for personnel evacuation and equipment rescue. Currently, flame-retardant modification of floor coatings largely relies on additive flame retardants, such as halogenated or phosphorus-based flame retardants. While halogenated flame retardants are highly effective, they release toxic and harmful gases and fumes during combustion, posing a threat to the environment and human health, and their application is strictly limited. Phosphorus-based flame retardants are relatively environmentally friendly, but traditional additive phosphorus-based flame retardants also face problems such as poor compatibility with the base resin, easy precipitation, and impact on coating transparency and mechanical properties. Furthermore, the durability of their flame-retardant effect is difficult to guarantee.

[0005] Achieving efficient, stable, and durable antistatic and flame-retardant properties simultaneously within a single floor coating system, while also considering the coating's basic physical and mechanical properties, chemical resistance, and environmental friendliness, is a pressing technical challenge in the field of cleanroom floor coatings. Existing technologies often struggle to find an ideal balance, and simple compounding of multiple functional additives frequently leads to mutual performance constraints or a decline in overall stability. Therefore, developing a novel, functionally integrated, and durable cleanroom floor coating material has significant practical importance and application value. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the present invention aims to solve the technical problem that existing cleanroom floor coating materials are difficult to achieve efficient and long-lasting flame retardant and antistatic properties at the same time, and that their comprehensive physical and mechanical properties and functional stability are difficult to meet the requirements of special use environments.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a flame-retardant and antistatic polymer coating material for cleanroom flooring, comprising the following components by mass percentage:

[0008] The functional phosphoric imidazole ionic liquid monomer is 18.0-22.0%, wherein the ionic liquid monomer is 1-vinyl-3-methylimidazolium bis(2-methoxyethyl) phosphate, with a molecular weight of 380-450 Da, wherein the distance between the imidazole ring and the phosphate group is 3-5 atomic distances, the phosphate group is substituted with dicoxy, and the vinyl group is located at the N1 position of the imidazole ring.

[0009] Silicon-modified epoxy acrylate prepolymer 45.0-48.0%, acrylic group density 0.8-1.2 mmol / g, epoxy group density 1.5-2.0 mmol / g, acrylic group to epoxy group density ratio 1.2:1-1.8:1, siloxane content 8.0-12.0%;

[0010] The molecularly imprinted crosslinking agent is 9.0-11.0%, wherein the crosslinking agent is N,N'-bisacrylamidotriethyl phosphate with a molecular weight of 380-450 Da and a molar ratio of phosphorus atoms to acrylamide groups of 1:2;

[0011] This invention innovatively uses N,N'-bisacrylamidotriethyl phosphate as a molecularly imprinted crosslinking agent, with a mass fraction of 9.0-11.0%. The crosslinking agent is designed based on the principle of molecular imprinting technology, and the molar ratio of phosphorus atoms to acrylamide groups is precisely controlled at 1:2. This stoichiometric ratio ensures that the crosslinking agent molecules can form a specific molecular recognition and binding mode with the ionic liquid monomer.

[0012] The phosphate groups in the molecularly imprinted crosslinking agent can form hydrogen bonds and electrostatic interactions with the imidazole rings in the ionic liquid monomer, pre-assembling into an ordered molecular arrangement during polymerization. The bisacrylamide groups then fix this ordered structure within the polymer network through a crosslinking reaction, forming a three-dimensional network structure with molecular recognition capabilities. This mechanism not only enhances the uniformity of ionic liquid monomer dispersion in the polymer but, more importantly, constructs continuous ion conduction channels, significantly improving the antistatic stability of the material.

[0013] The nano-cellulose / graphene composite filler contains 5.0-7.0% of the material, with a graphene to cellulose mass ratio of 1:1.5-1:2.5. The average particle size of the composite filler is 50-200 nm, and the graphene dispersion is greater than 0.95.

[0014] The photothermal synergistic initiator system comprises 3.0-4.0%, including 1.5-2.0% of a visible light-sensitive organic boron salt and 1.5-2.0% of a peroxide initiator;

[0015] This invention employs a photothermal synergistic initiator system with a total mass fraction of 3.0-4.0%, comprising 1.5-2.0% each of a visible light-sensitive organoboron salt and a peroxide initiator. This dual-initiator system is designed based on the concept of stepwise polymerization. Under LED illumination, the visible light-sensitive organoboron salt first initiates the free radical polymerization of acrylic acid groups, forming a preliminary network structure. The peroxide initiator then decomposes during the subsequent thermosetting process, initiating the ring-opening polymerization of epoxy groups and further crosslinking of the remaining acrylic acid groups.

[0016] The advantage of this stepwise initiation mechanism lies in its ability to precisely control the polymerization process and the formation of the network structure. The initial network formed during the photocuring stage provides the material with basic structural stability while retaining sufficient reactive groups for subsequent thermocuring. The deep crosslinking during the thermocuring stage further refines the network structure, achieving the final optimization of the material's properties.

[0017] Functional additives 3.0-5.0%, including leveling agents, defoamers and ultraviolet absorbers;

[0018] The total amount of functional additives added accounts for 3.0-5.0% of the total mass of the coating material. These additives are carefully selected and formulated to optimize the coating's application performance, improve the appearance of the paint film, and extend the coating's long-term service life. Specifically, functional additives mainly include the following types of substances, and their recommended addition amounts (percentage of the total mass of the coating material) can be detailed as follows:

[0019] Leveling agent: This is typically an additive that effectively reduces the surface tension of the coating, promotes film leveling, and eliminates surface defects such as pinholes and orange peel. Examples include polyether-modified polysiloxanes, acrylates, or fluorocarbon-modified polymers. The typical addition amount in this invention ranges from 0.5% to 1.5%. Selecting an appropriate leveling agent and its dosage helps to form a smooth and even coating surface, which is crucial for maintaining the cleanliness of cleanrooms.

[0020] Defoamer (Anti-foaming Agent): Primarily used to eliminate air bubbles generated during the production, mixing, transportation, and application of coatings, and to prevent pinholes or surface defects from forming during the curing process due to bubble rupture. Commonly used defoamers include mineral oils, silicones (such as polydimethylsiloxane), polyethers, or their modified forms. The typical addition amount in this invention ranges from 0.3% to 1.0%. Effective defoaming is crucial for ensuring the density and appearance integrity of the coating.

[0021] UV absorbers and / or light stabilizers (HALS): These additives protect coating materials from the degradation effects of ultraviolet light, improve the coating's weather resistance and color stability, and delay aging, yellowing, chalking, or cracking caused by light exposure. UV absorbers (such as benzotriazoles, benzophenones, and triazines) absorb ultraviolet energy and release it as heat or other harmless forms; light stabilizers (usually hindered amine light stabilizers, HALS) inhibit photo-oxidative degradation by capturing free radicals. In practical applications, the two are often used together to achieve better protective effects.

[0022] The molar ratio of the functional phosphoric imidazole ionic liquid monomer to the molecularly imprinted crosslinking agent is 3.2:1-4.8:1, the pH value of the system is 6.5-7.2, and the ratio of the total molar number of phosphorus element to the molar number of imidazole ring is 1.8:1-2.2:1.

[0023] Preferably, the functional phosphoroimidazole ionic liquid monomer has a water content of less than 0.2%, an acid value of less than 2 mg KOH / g, a vinyl substitution degree of more than 95% at the N1 position of the imidazole ring, and a dialkoxy substitution rate of 100% for the phosphate group.

[0024] This invention uses 1-vinyl-3-methylimidazolium bis(2-methoxyethyl) phosphate as the core functional monomer, with a molecular weight controlled within the range of 380-450 Da. The innovative design of this molecule lies in the precise connection between the imidazole ring cationic structure and the phosphate group anionic structure through a spacing of 3-5 atoms, forming a unique ion-pair structure. The vinyl substituent at the N1 position of the imidazole ring endows the molecule with polymerizability, enabling it to be fixed in situ within the polymer network via free radical polymerization, fundamentally solving the technical problem of easy migration and precipitation of traditional antistatic agents.

[0025] The phosphate group is designed with alkoxy substitution. This structure not only provides excellent flame retardant properties, but more importantly, through the coordination chemistry of the phosphorus atom, it can form a stable chemical bond with the polymer matrix, achieving permanent fixation of the flame retardant function. The ionic conductivity mechanism of the imidazole ring and the flame retardant mechanism of the phosphate group work synergistically within the same molecule, completely breaking through the technical bottleneck of the conflict between flame retardant and conductive functions in traditional technologies.

[0026] Preferably, the viscosity of the silicone-modified epoxy acrylate prepolymer at 25°C is 2000-5000 mPa·s, and the purity of the molecularly imprinted crosslinking agent is greater than 98%.

[0027] This invention uses a silicone-modified epoxy acrylate prepolymer as the matrix resin, with a mass fraction controlled at 45.0-48.0%. The innovation of this prepolymer lies in its simultaneous presence of two different reactive functional groups: acrylic groups and epoxy groups. The density of acrylic groups is 0.8-1.2 mmol / g, and the density of epoxy groups is 1.5-2.0 mmol / g. This bifunctional design allows the polymer network to be constructed simultaneously through two different chemical reaction mechanisms: the acrylic groups participate in photo-initiated free radical polymerization, while the epoxy groups undergo ring-opening polymerization during thermosetting.

[0028] The density ratio of acrylic groups to epoxy groups is controlled at 1.2:1-1.8:1. This precise control ensures the coordinated progress of the two polymerization reactions and avoids network defects caused by reaction competition. The siloxane content is controlled at 8.0-12.0%. The introduction of siloxane segments not only improves the flexibility and weather resistance of the polymer, but more importantly, through the special electronic structure of silicon atoms, it provides a stable coordination environment for the ionic liquid monomers, enhancing the stability of the ionic conductivity channels.

[0029] Preferably, the specific surface area of ​​the nanocellulose / graphene composite filler is 150-300 m². 2 / g, wherein the graphene sheet thickness is 1-3nm, the lateral dimension is 1-5μm, and the purity is greater than 99%.

[0030] This invention employs a unique nanocellulose / graphene composite filler system, with a mass fraction controlled between 5.0% and 7.0%. The mass ratio of graphene to cellulose is precisely controlled within the range of 1:1.5 to 1:2.5, a ratio based on the template-directing mechanism of nanocellulose. Nanocellulose possesses a high aspect ratio one-dimensional nanostructure and abundant surface hydroxyl groups, enabling it to form a stable composite structure with graphene sheets through hydrogen bonding and π-π interactions.

[0031] Nanocellulose acts as both a dispersant and a template. On one hand, it prevents graphene aggregation by forming hydrogen bonds with oxygen-containing functional groups on the graphene surface through its hydrophilic groups. On the other hand, the one-dimensional nanostructure of cellulose guides the graphene sheets to align in a specific direction, forming a continuous conductive network. The average particle size of the composite filler is controlled at 50-200 nm, and the graphene dispersion is greater than 0.95. This high dispersion ensures the continuity and stability of the conductive network.

[0032] Preferably, a method for preparing a flame-retardant and antistatic polymer coating material for cleanroom flooring includes the following steps:

[0033] Step 1: Raw material pretreatment. The functional phosphoroimidazole ionic liquid monomer is placed in a rotary evaporator and dehydrated for 2.0-2.5 hours at 45-55℃ and a vacuum of 0.08-0.10MPa. After cooling to room temperature, it is stored under nitrogen protection. The graphene and cellulose in the nanocellulose / graphene composite filler are mixed at a mass ratio of 1:2.0. 20% of the silicon-modified epoxy acrylate prepolymer is added as a dispersion medium. The mixture is treated by ultrasonic dispersion with an ultrasonic power of 200-300W, an ultrasonic frequency of 20-40kHz, and a treatment time of 30-45 minutes. The temperature is kept below 35℃ by ice bath cooling.

[0034] Step 2: Staged mixing, carried out in a reaction vessel under nitrogen protection, in the following order: First stage: Mix the pretreated functionalized phosphoric imidazole ionic liquid monomer and silicon-modified epoxy acrylate prepolymer at a stirring speed of 200-300 rpm, temperature of 25±2℃, for 30-35 minutes; Second stage: Add pre-dispersed nanocellulose / graphene composite filler, stir for 15-20 minutes, then add the molecularly imprinted crosslinking agent at a stirring speed of 400-500 rpm for 20-25 minutes; Third stage: Add the photothermal synergistic initiator system under light-shielding conditions, followed by the functional additives, at a stirring speed of 150-200 rpm for 10-15 minutes; Then, perform vacuum degassing at a vacuum degree of 0.08-0.10 MPa for 15-20 minutes.

[0035] Step 3: Substrate pretreatment and coating application. The substrate is mechanically sanded to a surface roughness of Ra 1.6-3.2μm, cleaned and dried until the moisture content is less than 4%, and then coated with a penetrating primer at a rate of 150-200g / m². 2 Dry for 4-6 hours, then apply the coating material to a thickness of 2.0-3.0 mm using a microstructured coating head. The ambient temperature during construction is 20-25℃, and the relative humidity is 45-65%.

[0036] Step 4: Step-by-step curing. First, perform light pre-curing using a visible light LED light source with a wavelength of 450-470nm and a light intensity of 8-12mW / cm². 2 Curing time is 60-120 seconds, and the temperature is controlled below 30℃. After an interval of no more than 30 minutes, heat curing is carried out. The heating rate is 2-4℃ / min to raise the temperature to 60-80℃, and the temperature is kept for 2-4 hours. The temperature fluctuation is controlled within ±2℃.

[0037] Step 5: Post-treatment, natural aging at room temperature for 24-48 hours, ambient temperature 20-25℃, relative humidity 50-60%.

[0038] Preferably, in the raw material pretreatment step, the water content of the functional phosphoric imidazole ionic liquid monomer after dehydration treatment is less than 0.2%, the graphene dispersion of the nanocellulose / graphene composite filler after pretreatment is greater than 0.95, and the nitrogen flow rate during the staged mixing process is 100-200 mL / min.

[0039] Preferably, after the phased mixing step is completed, a quality control test is performed, and the viscosity of the mixture at 25°C is 800-1200 mPa·s, the pH value is 6.5-7.2, the solid content is 95-98%, and the gelation time is 45-65 minutes.

[0040] Preferably, in the photocuring step, the height of the LED light source is 150-200mm, the moving speed is 0.5-1.0m / min, and the target gel content is 40-60%. In the thermal curing step, the cooling rate does not exceed 5℃ / min, and the target gel content is 85-95%.

[0041] Preferably, in the substrate pretreatment step, mechanical sanding uses 80-120 grit sandpaper with a sanding depth of 0.5-1.0 mm, cleaning treatment uses an industrial cleaner with a concentration of 5-10% for 10-15 minutes, and drying temperature is 40-60℃.

[0042] Preferably, in the post-processing step, the surface is kept covered with dust during the natural aging process to avoid direct sunlight. After aging, the surface is finished by lightly sanding with 400-600 grit sandpaper to remove surface defects. After sanding, the surface dust is cleaned with a lint-free cloth, and the surface flatness is controlled within ±2mm / 2m.

[0043] The preparation method of this invention employs a multi-step, precisely controlled process route, with each step having its specific technical mechanism. The raw material pretreatment stage ensures optimal reaction states for each component through precise dehydration and dispersion treatment. The staged mixing process, based on the differences in compatibility and reactivity between different components, utilizes progressive feeding and differentiated stirring parameters to achieve uniform dispersion and preliminary pre-assembly of the components.

[0044] The stepwise curing process is the core technical feature of this invention. The organic combination of photopre-curing and thermo-curing enables precise control of the polymerization reaction. The mild conditions of the photopre-curing stage prevent the decomposition of heat-sensitive components and provide a stable reaction basis for subsequent thermo-curing. The gradual heating and precise temperature control during the thermo-curing stage ensure the complete formation of the network structure and the full realization of its performance.

[0045] The entire preparation process was designed with full consideration of the interaction mechanism and reaction kinetics between the components. Through precise control of process parameters, the material structure and properties were precisely regulated, providing a reliable technical guarantee for the application of cleanroom flooring.

[0046] This invention provides a flame-retardant and antistatic polymer coating material for cleanroom flooring. It possesses the following beneficial effects:

[0047] 1. This invention provides a cleanroom floor coating material and its preparation method that combine excellent flame retardancy and long-lasting antistatic properties. By integrating phosphorus and imidazole ring structures into a polymerizable ionic liquid monomer at the molecular level and covalently bonding them to the polymer network, the problems of easy migration and short-lasting function of traditional additive flame retardants and antistatic agents are fundamentally solved. This design not only ensures that the floor can continuously and effectively prevent the spread of fire and the accumulation of static charge during long-term use, but also reduces maintenance costs and safety hazards caused by material aging and failure due to the stable presence of functional components. It is particularly suitable for cleanroom environments with extremely high requirements for cleanliness and safety.

[0048] 2. This invention significantly optimizes the synergistic effect of ion conduction channels and electronic conductivity networks within the floor coating by introducing a molecularly imprinted crosslinking agent and combining it with graphene composite fillers templated with nanocellulose. The application of molecular imprinting technology enables functional ionic liquids to form more ordered and efficient charge transport pathways within the polymer matrix, while the excellent dispersing effect of nanocellulose on graphene ensures the construction of a continuous conductive network even with low addition levels. This structural optimization allows the floor coating to achieve excellent antistatic properties while also exhibiting good performance uniformity, ensuring the reliability and consistency of electrostatic protection across the entire cleanroom floor surface.

[0049] 3. The silicone-modified epoxy acrylate prepolymer used in this invention, combined with an innovative step-by-step synergistic curing process of photocuring and thermocuring, endows the cleanroom floor coating with excellent comprehensive physical and mechanical properties and chemical stability. The introduction of siloxane segments enhances the coating's flexibility and weather resistance, while the step-by-step curing mechanism ensures the formation of a dense and highly cross-linked network structure. This gives the floor not only excellent hardness, wear resistance, and strong adhesion to the substrate, enabling it to withstand frequent personnel movement and equipment movement within the cleanroom, but also good resistance to chemical corrosion, resisting the effects of cleaning agents and chemicals that may be encountered during production, thus extending the floor's service life.

[0050] 4. The preparation method of this invention achieves effective control and optimization of the final performance of the floor coating material through refined raw material pretreatment, programmed staged mixing, and advanced coating application and curing technologies. For example, specific purification treatment of functional monomers and innovative pre-dispersion technology for conductive fillers ensure the full utilization of the functions of each component. Furthermore, precise control of light parameters and heat treatment conditions in the stepwise synergistic curing process guarantees that the coating can form an ideal microstructure according to a predetermined mechanism. This systematic preparation strategy not only improves the stability and reproducibility of product performance but also provides a reliable technical approach for the industrial production of high-performance cleanroom floor materials. Attached Figure Description

[0051] Figure 1 Flowchart of the preparation method for a flame-retardant and antistatic polymer coating material for cleanroom flooring. Detailed Implementation

[0052] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] Example:

[0054] Example 1: Standard Formulation and Preparation Method

[0055] Coating material composition (by weight):

[0056] Functional phosphoroimidazole ionic liquid monomer: 20.0%

[0057] Silicone-modified epoxy acrylate prepolymer: 46.5%

[0058] Molecularly imprinted crosslinking agent: 10.0%

[0059] Nanocellulose / graphene composite filler: 6.0% (graphene:nanocellulose = 1:2.0)

[0060] Photothermal synergistic initiator system: 3.5% (organoboron salt: peroxide = 1:1)

[0061] Functional additives: 4.0% (leveling agent 2.0%, defoamer 1.0%, UV absorber 1.0%)

[0062] Preparation method:

[0063] Step 1: Raw material pretreatment

[0064] Place 200g of functional phosphoroimidazole ionic liquid monomer in a 500mL rotary evaporation flask, connect it to a rotary evaporator, set the water bath temperature to 50℃ and the vacuum degree to 0.09MPa, and rotary evaporate for 2.0 hours. After cooling to 25℃, introduce nitrogen gas to break the vacuum and seal for storage.

[0065] Weigh 20g of graphene and 40g of nanocellulose and add them to a beaker containing 186g of silicon-modified epoxy acrylate prepolymer. Disperse the mixture using a high-power ultrasonic cell disruptor. Set the ultrasonic power to 250W, the ultrasonic frequency to 30kHz, and the dispersion time to 40 minutes. The entire process is carried out in an ice-water bath to ensure that the material temperature is below 30℃.

[0066] Step 2: Phased mixing

[0067] In a 1000mL four-necked flask equipped with a mechanical stirrer, thermometer, and nitrogen protection, first add 465g of silicone-modified epoxy acrylate prepolymer (excluding the portion used for dispersing filler), then add 200g of pretreated functional phosphoroimidazole ionic liquid monomer. Turn on nitrogen protection and control the flow rate at 150mL / min. Mix at 25°C and a stirring speed of 250rpm for 30 minutes.

[0068] Next, the pre-dispersed nanocellulose / graphene composite filler (containing 186g of prepolymer) was slowly added to the above mixture, and stirring was continued for 15 minutes. Then, 100g of molecularly imprinted crosslinking agent was added, the stirring speed was increased to 450rpm, and stirring was continued for 20 minutes.

[0069] Under light-shielding conditions, add 35g of the photothermal synergistic initiator system, reduce the stirring speed to 180rpm, and mix for 10 minutes. Finally, add 40g of functional additives and continue stirring for 10 minutes.

[0070] The uniformly mixed material is transferred to a vacuum degassing device and degassed for 15 minutes under a vacuum of 0.09 MPa until no obvious bubbles escape.

[0071] Step 3: Substrate pretreatment and coating application

[0072] Select C25 concrete substrate and mechanically sand it using 100-grit sandpaper until the surface roughness reaches Ra2.4μm. Remove surface dust using an industrial vacuum cleaner, then wipe it clean with anhydrous ethanol and dry it in a 60°C oven for 4 hours, ensuring the substrate moisture content is below 2%.

[0073] Apply a uniform layer of epoxy penetrating primer using a roller coating method, with the coating amount controlled at 180g / m². 2 Dry at room temperature (23°C, RH 50%) for 5 hours.

[0074] Using an automated coating machine equipped with a microstructured coating head, the coating material prepared in step 2 was uniformly applied to the pretreated substrate surface, with the wet film thickness controlled at 2.5 mm. The application environment was maintained at a temperature of 22°C and a relative humidity of 55%.

[0075] Step 4: Step-by-step curing

[0076] Pre-curing: The coated substrate is immediately placed under a visible light LED curing device with a wavelength of 460nm and a light intensity controlled at 10mW / cm². 2 The light source is 180mm away from the coating surface and moves through the curing zone at a speed of 0.8m / min, with a total illumination time of approximately 90 seconds. During the curing process, the coating surface temperature is monitored to ensure it does not exceed 28℃.

[0077] Thermal curing: After photocuring, let stand for 15 minutes, then transfer the sample into a programmed temperature oven. Increase the temperature from room temperature to 70°C at a rate of 3°C / min, and hold at 70°C for 3 hours. After holding, allow to cool naturally to room temperature.

[0078] Step 5: Post-processing

[0079] The cured sample was allowed to age naturally at room temperature (23°C, RH55%) for 36 hours, during which time direct sunlight was avoided and the sample was covered with a dustproof film.

[0080] After aging, lightly sand the coating surface with 500-grit sandpaper to remove any minor imperfections, then wipe it clean with a lint-free cloth. Finally, check the surface smoothness of the coating, which should be ±1.5mm / 2m.

[0081] Example 2:

[0082] Coating material composition (by weight):

[0083] Functional phosphoroimidazole ionic liquid monomer: 18.0%

[0084] Silicone-modified epoxy acrylate prepolymer: 45.0%

[0085] Molecularly imprinted crosslinking agent: 9.0%

[0086] Nanocellulose / graphene composite filler: 5.0% (graphene:nanocellulose = 1:1.5)

[0087] Photothermal synergistic initiator system: 3.0% (organoboron salt: peroxide = 1:1)

[0088] Functional additives: 3.0% (leveling agent 1.0%, defoamer 0.5%, UV absorber 0.5%, other additives 1.0%)

[0089] Preparation method:

[0090] Step 1: Raw material pretreatment

[0091] 180g of functional phosphoroimidazole ionic liquid monomer was placed in a rotary evaporator, the water bath temperature was set to 45℃, the vacuum degree was controlled at 0.08MPa, and rotary evaporation was carried out for 2.5 hours.

[0092] Weigh 20g of graphene and 30g of nanocellulose and add them to a beaker containing 180g of silicon-modified epoxy acrylate prepolymer. The ultrasonic power is 200W, the ultrasonic frequency is 20kHz, the dispersion time is 45 minutes, and the ice water bath temperature is below 35℃.

[0093] Step 2: Phased mixing

[0094] In the reaction vessel, first add 450g of silicone-modified epoxy acrylate prepolymer (excluding the portion used for dispersing the filler), then add 180g of pretreated functional phosphoroimidazole ionic liquid monomer. Nitrogen flow rate is controlled at 100mL / min. Mix at 23°C and a stirring speed of 200rpm for 35 minutes.

[0095] Add the pre-dispersed nanocellulose / graphene composite filler and stir for 20 minutes. Then add 90g of molecularly imprinted crosslinking agent, increase the stirring speed to 400rpm, and continue stirring for 25 minutes.

[0096] Add 30g of the photothermal synergistic initiator system, reduce the stirring speed to 150rpm, and mix for 12 minutes. Finally, add 30g of functional additives and continue stirring for 15 minutes.

[0097] Vacuum degassing: vacuum degree 0.08MPa, time 20 minutes.

[0098] Step 3: Substrate pretreatment and coating application

[0099] Substrate sanding: 80-grit sandpaper, surface roughness Ra 1.6μm. Clean and dry until moisture content is less than 4%.

[0100] Primer: Application rate 150g / m 2 Dry for 4 hours.

[0101] Coating application: Wet film thickness 2.0mm. Ambient temperature 20℃, relative humidity 45%.

[0102] Step 4: Step-by-step curing

[0103] Light pre-curing: Light source wavelength 450nm, light intensity 8mW / cm² 2 The light source distance is 150mm, the moving speed is 1.0m / min, and the total illumination time is 60 seconds. The coating surface temperature does not exceed 30℃.

[0104] Heat curing: Let stand for 30 minutes. Increase the temperature at a rate of 2℃ / min to 60℃ and hold for 4 hours.

[0105] Step 5: Post-processing

[0106] Natural aging for 24 hours, ambient temperature 20℃, RH 50%.

[0107] Surface finishing: Sanded with 400-grit sandpaper, surface flatness ±2mm / 2m.

[0108] Example 3:

[0109] Coating material composition (by weight):

[0110] Functional phosphoroimidazole ionic liquid monomer: 22.0%

[0111] Silicone-modified epoxy acrylate prepolymer: 48.0%

[0112] Molecularly imprinted crosslinking agent: 11.0%

[0113] Nanocellulose / graphene composite filler: 7.0% (graphene:nanocellulose = 1:2.5)

[0114] Photothermal synergistic initiator system: 4.0% (organoboron salt: peroxide = 1:1)

[0115] Functional additives: 5.0% (leveling agent 2.0%, defoamer 1.0%, UV absorber 1.0%, other additives 1.0%)

[0116] Preparation method:

[0117] Step 1: Raw material pretreatment

[0118] 220g of functional phosphoroimidazole ionic liquid monomer was placed in a rotary evaporator, the water bath temperature was set to 55℃, the vacuum degree was controlled at 0.10MPa, and rotary evaporation was carried out for 2.0 hours.

[0119] Weigh 20g of graphene and 50g of nanocellulose and add them to a beaker containing 201.6g of silicon-modified epoxy acrylate prepolymer. The ultrasonic power is 300W, the ultrasonic frequency is 40kHz, the dispersion time is 30 minutes, and the ice water bath temperature is below 35℃.

[0120] Step 2: Phased mixing

[0121] In the reaction vessel, first add 480g of silicone-modified epoxy acrylate prepolymer (excluding the portion used for dispersing filler), then add 220g of pretreated functional phosphoroimidazole ionic liquid monomer. Nitrogen flow rate is controlled at 200mL / min. Mix at 27°C and a stirring speed of 300rpm for 30 minutes.

[0122] Add the pre-dispersed nanocellulose / graphene composite filler and stir for 15 minutes. Then add 110g of molecularly imprinted crosslinking agent, increase the stirring speed to 500rpm, and continue stirring for 20 minutes.

[0123] Add 40g of the photothermal synergistic initiator system, reduce the stirring speed to 200rpm, and mix for 8 minutes. Finally, add 50g of functional additives and continue stirring for 10 minutes.

[0124] Vacuum degassing: vacuum degree 0.10MPa, time 15 minutes.

[0125] Step 3: Substrate pretreatment and coating application

[0126] Substrate sanding: 120-grit sandpaper, surface roughness Ra 3.2μm. Clean and dry until moisture content is less than 1%.

[0127] Primer: Application rate 200g / m 2 Dry for 6 hours.

[0128] Coating application: Wet film thickness 3.0mm. Ambient temperature 25℃, relative humidity 65%.

[0129] Step 4: Step-by-step curing

[0130] Pre-curing: Light source wavelength 470nm, light intensity 12mW / cm² 2 The light source distance is 200mm, the moving speed is 0.5m / min, and the total illumination time is 120 seconds. The coating surface temperature does not exceed 25℃.

[0131] Heat curing: Let stand for 10 minutes. Increase the temperature at a rate of 4℃ / min to 80℃ and hold for 2 hours.

[0132] Step 5: Post-processing

[0133] Natural aging for 48 hours, ambient temperature 25℃, RH 60%.

[0134] Surface finishing: Sanded with 600-grit sandpaper, surface flatness ±1mm / 2m.

[0135] Comparative Example

[0136] Comparative Example 1: Compared with Example 1, the difference is that 20.0% by weight of the "functional phosphoroimidazole ionic liquid monomer (1-vinyl-3-methylimidazolium bis(2-methoxyethyl) phosphate)" in Example 1 was replaced with an equal amount of a simple physical mixture of conventional non-polymeric quaternary ammonium salt antistatic agent (e.g., dodecyltrimethylammonium bromide, 10.0%) and conventional phosphate ester flame retardant (e.g., tri(2-chloroethyl) phosphate, 10.0%); the remaining components and preparation steps are the same as in Example 1.

[0137] Comparative Example 2: Compared with Example 1, the difference is that 10.0% by weight of “molecularly imprinted crosslinking agent (N,N'-bisacrylamidotriethyl phosphate)” in Example 1 was replaced with an equimolar amount of conventional non-specific acrylate crosslinking agent (e.g., 1,6-hexanediol diacrylate); the remaining components and preparation steps are the same as in Example 1.

[0138] Comparative Example 3: Compared with Example 1, the difference is that in the "Step 4: Stepwise Curing" of the preparation method, the thermal curing step is cancelled. That is, after the visible light LED light pre-curing is completed, the subsequent heating and heat preservation thermal curing treatment is no longer carried out, and the process directly proceeds to "Step 5: Post-processing"; the remaining components and preparation method steps are the same as in Example 1.

[0139] Comparative Example 4: The difference compared to Example 1 is as follows:

[0140] The 6.0% by weight of “nanocellulose / graphene composite filler” in Example 1 was replaced with an equal part by weight of ordinary graphene micro powder without nanocellulose composite.

[0141] In Step 1: Raw Material Pretreatment of the preparation method, the specific pre-dispersion step of "adding silicon-modified epoxy acrylate prepolymer as a dispersion medium and treating it by ultrasonic dispersion" for graphene is omitted; the 6.0% by weight of ordinary graphene micropowder is added directly in the second stage of Step 2: Staged Mixing at the same time as the original nanocellulose / graphene composite filler. The remaining components and preparation method steps are the same as in Example 1.

[0142] Test experiment:

[0143] Test Example 1: This test example aims to evaluate and compare the differences between the samples of Examples 1-3 and Comparative Example 1 in terms of flame retardant properties, initial antistatic properties, and antistatic property durability.

[0144] 1. Sample preparation:

[0145] All samples (Example 1, Example 2, Example 3, Comparative Example 1) were prepared into coated templates or strip specimens with dimensions conforming to the requirements of each test standard according to the preparation method described therein.

[0146] Before conducting any tests, all samples were conditioned for at least 48 hours under standard laboratory conditions (temperature 23±2℃, relative humidity 50±5%), unless otherwise specified in the specific standard.

[0147] 2. Flame retardant performance test:

[0148] 2.1 Limiting Oxygen Index (LOI) Test Standard: Refer to GB / T2406.2-2009 "Determination of Combustion Behavior by Oxygen Index Method for Plastics - Part 2: Room Temperature Test".

[0149] Sample size: Prepare strip samples with dimensions of (150±5)mm×(10±0.5)mm×(coating thickness, usually 2-3mm), with at least 5 samples per group.

[0150] Experimental steps:

[0151] 1. Hold the prepared sample vertically in the center of the combustion chamber of the oxygen index meter.

[0152] 2. Adjust the flow rates of oxygen and nitrogen to set an initial oxygen concentration.

[0153] 3. Ignite the top of the sample with a standard igniter for 5 seconds, then remove the igniter.

[0154] 4. Observe whether the sample continues to burn. If the sample continues to burn for more than 180 seconds or the burning length exceeds 50 mm, it is determined to be continuously burning under that oxygen concentration.

[0155] 5. Adjust the oxygen concentration according to the "lifting method" or "up and down method", and repeat the test with a new sample until the lowest oxygen concentration that can just maintain combustion of the sample is found.

[0156] 6. Record the limiting oxygen index value for each group of samples and calculate the average value.

[0157] 2.2 Vertical flammability rating (UL94) test

[0158] Test standard: Refer to ANSI / UL94-2013 "Tests on the flammability of plastic materials for use in equipment and appliance components".

[0159] Sample size: Prepare strip samples with dimensions of (125±5)mm×(13±0.5)mm×(coating thickness), with at least 5 samples per group.

[0160] Experimental steps:

[0161] 1. Hang the prepared sample vertically on the sample holder of the UL94 combustion test chamber, with the lower end of the sample about 300mm away from the degreased cotton layer.

[0162] 2. Point the standard Bunsen burner flame (flame height 20mm) at the center of the lower end of the sample, apply the flame for 10 seconds, and then remove the flame.

[0163] 3. Immediately record the first flaming combustion time (t1).

[0164] 4. If the flame goes out within 30 seconds on the first attempt, immediately apply the flame again for 10 seconds, and then remove the flame.

[0165] 5. Record the second flaming combustion time (t2) and the flameless combustion (glow) time (t3).

[0166] 6. Observe whether burning droplets ignite the degreased cotton below.

[0167] 7. Based on the test results of the 5 samples, the ratings were determined according to the V-0, V-1, and V-2 criteria in the UL94 standard.

[0168] 3. Antistatic performance test:

[0169] 3.1 Initial surface resistivity test standard: Refer to GB / T1410-2006 "Determination of conductive, dissipative and insulating resistivity of plastics" or ASTM D257-14 "Standard Test Methods for DC Resistance or Conductance of Insulating Materials".

[0170] Sample size: Prepare a flat coated sample with a size of not less than 100mm × 100mm, or a circular sample with a diameter of not less than 100mm.

[0171] Experimental steps:

[0172] 1. Place the prepared sample on the test platform of the high resistance meter, ensuring good contact between the electrode (such as a three-electrode system or concentric electrodes) and the sample surface.

[0173] 2. Set the test voltage to 500VDC (or select an appropriate voltage based on the material properties).

[0174] 3. Apply voltage for 60 seconds.

[0175] 4. Read and record the stabilized resistance value.

[0176] 5. Calculate the surface resistivity (unit: Ω or Ω / sq) based on the electrode geometry parameters. Test at least 3 different locations for each sample group and take the average value.

[0177] 3.2 Durability test of antistatic properties (surface resistivity after aging)

[0178] Aging treatment methods (choose one or more):

[0179] Water washing and aging: Immerse the sample (or a new parallel sample) with the initial surface resistivity measured completely in deionized water at 50±2℃ for 24 hours. After removal, rinse with deionized water and then dry in an oven at 50±2℃ for 4 hours or until constant weight. Re-condition under standard laboratory conditions for 24 hours.

[0180] Solvent wiping aging: Fix the sample (or a new parallel sample) with the initial surface resistivity measured on a flat surface. Wipe the sample surface 50 times (one back and forth stroke counts as one) with a load of about 1 kg using degreased cotton or non-woven cloth soaked in anhydrous ethanol. After wiping, let it air dry naturally and then condition it again under standard laboratory conditions for 4 hours.

[0181] Surface resistivity testing steps after aging:

[0182] 1. For the samples that have undergone the above aging treatment and readjustment, the surface resistivity shall be measured in accordance with the same steps as in “3.1 Initial Surface Resistivity Test”.

[0183] 2. Record the surface resistivity value after aging.

[0184] Experimental data:

[0185] Table 1: Comparative Test Data of Core Functional Material Performance and Durability

[0186]

[0187]

[0188] The experimental results clearly demonstrate the significant advantages of the coating material constructed in this invention in terms of flame retardancy and antistatic properties. Compared with the comparative samples using traditional physical addition methods, the samples of this invention exhibit a higher limiting oxygen index and a superior vertical burning rating, mainly attributed to the unique molecular design of its core component—the functional phosphorus-based imidazole ionic liquid monomer. This monomer molecule integrates the inherent flame-retardant properties provided by phosphorus with the ionic conductivity imparted by the imidazole ring structure, unifying flame retardancy and antistatic functions at the molecular level, thus achieving a highly efficient synergistic effect on the overall material. The initial surface resistivity test results also confirm this; the samples of this invention exhibit significantly lower surface resistivity, indicating superior electrostatic charge dissipation capabilities. This stems from the effective charge transport pathway constructed by the ion pair structure formed by the imidazole cations and phosphate anions within the ionic liquid.

[0189] More importantly, the samples in this invention exhibited excellent durability of antistatic properties after undergoing simulated aging treatments such as water washing and solvent wiping. Although the surface resistivity increased to some extent after aging, it remained far lower than that of the comparative samples, and remained within the effective antistatic range. This superior durability stems directly from the vinyl active group introduced into the molecular structure of the functional phosphoryl imidazole ionic liquid monomer. This vinyl group allows the ionic liquid monomer to act as a reactive monomer, permanently anchored in the polymer network backbone through chemical bonding during the curing process of the coating material. This in-situ polymerization and covalent bonding fundamentally overcomes the inherent defects of traditional small-molecule antistatic agents, which are prone to migration, dissolution, or wiping removal due to physical adsorption or simple blending, thus ensuring the long-term stable performance of the antistatic function.

[0190] In summary, through innovative molecular engineering design of the core functional monomers, this invention successfully integrates flame retardant and antistatic functions, and achieves permanent fixation of the functional components in the polymer matrix by introducing reactive groups. This strategy not only enhances the initial effectiveness of each function, but more importantly, endows the material with excellent performance durability, effectively solving the problem of balancing functionality and durability in traditional technical solutions. This gives the coating material of this invention significant technical advantages and application prospects in high-end application fields such as cleanroom flooring requiring long-lasting, stable flame retardant and antistatic properties.

[0191] Test Example 2:

[0192] This test case aims to evaluate, by comparing the samples of Examples 1-3 with those of Comparative Examples 2 and 4, the contribution and stability of the application of the molecularly imprinted crosslinking agent and the nanocellulose / graphene composite filler and its specific pre-dispersion process in this invention to the final conductivity (mainly manifested as antistatic properties) of the material.

[0193] 1. Sample preparation:

[0194] All samples (Example 1, Example 2, Example 3, Comparative Example 2, Comparative Example 4) were prepared into coated samples that met the requirements of each test standard according to the preparation method described therein.

[0195] Before conducting any tests, all samples were conditioned for at least 48 hours under standard laboratory conditions (temperature 23±2℃, relative humidity 50±5%).

[0196] 2. Detailed comparison and uniformity evaluation of antistatic properties:

[0197] Test standard: Refer to GB / T1410-2006 "Determination of conductivity, dissipation and insulation resistivity of plastics".

[0198] Sample size: Prepare a flat coated sample with a size of not less than 150mm×150mm to facilitate multi-point testing and ensure uniform thickness.

[0199] Experimental steps:

[0200] 1. Place the prepared sample on the test platform of the high resistance meter.

[0201] 2. Surface resistivity test: Use a three-electrode system (such as a standard concentric circle electrode).

[0202] 3. Volume resistivity test: A disk electrode system with a protective electrode is used.

[0203] 4. Set the test DC voltage to 500V (or select an appropriate voltage based on material properties and standard recommendations).

[0204] 5. Apply voltage and maintain the voltage for 60 seconds. After the current stabilizes, read the resistance value.

[0205] 6. Based on the geometry of the electrodes used and the measured resistance values, calculate the surface resistivity (unit: Ω or Ω / sq) and volume resistivity (unit: Ω·cm).

[0206] 7. Uniformity Assessment: For each surface resistivity test sample, select at least 5 different, uniformly distributed test points for measurement. Record the surface resistivity at each point and calculate the average value and standard deviation. The magnitude of the standard deviation can indirectly reflect the uniformity of the material's electrical conductivity / antistatic properties.

[0207] 3. Stability assessment of antistatic properties under temperature and humidity disturbances:

[0208] Test standard: Same as 2.1.

[0209] Objective: To evaluate the stability of antistatic properties of different samples under slight environmental changes, indirectly reflecting the stability of ion channels or the robustness of conductive network structures that may be brought about by molecular imprinting.

[0210] Experimental steps:

[0211] First, the initial surface resistivity of the sample was measured under standard conditioning conditions (23±2℃, RH50±5%) (same as step 2.1).

[0212] Then, the same batch of samples was transferred to another environmental chamber with slightly different temperature and humidity, for example, condition A: 28±2℃, RH 60±5%; condition B: 18±2℃, RH 40±5%. The samples were allowed to equilibrate under the new temperature and humidity conditions for at least 24 hours.

[0213] Under the new temperature and humidity conditions, the sample is immediately removed and the surface resistivity is measured quickly (e.g., within 5 minutes).

[0214] The changes in surface resistivity of samples under different temperature and humidity conditions were compared. Samples with smaller changes were considered to have better environmental stability.

[0215] Table 2: Comparison of Conductivity and Stability Test Data

[0216]

[0217]

[0218] Experimental results further reveal the unique advantages of this invention in conductive network construction and performance optimization. By comparing the surface resistivity and volume resistivity data of different samples, it can be observed that the samples of the embodiments of this invention generally exhibit significantly better conductivity than the comparative samples, i.e., lower resistivity values. In particular, compared with Comparative Example 4, the nanocellulose / graphene composite filler and specific pre-dispersion process used in its embodiments obviously help graphene form more effective and continuous conductive pathways in the matrix, thereby significantly reducing the overall resistance of the material. At the same time, the improvement in conductivity of the sample of the embodiments compared with Comparative Example 2 (which used a conventional non-specific crosslinking agent) also indirectly reflects the positive role of molecularly imprinted crosslinking agents in synergistically constructing efficient ion conduction channels with functional phosphoryl imidazolium ionic liquids. This specific crosslinking may promote a more ordered arrangement of ionic liquids in the polymer network.

[0219] The uniformity of antistatic properties is a crucial indicator of the reliability of flooring materials. Looking at the standard deviation data of surface resistivity, the samples in this invention typically exhibit a smaller standard deviation, indicating a more uniform distribution of antistatic properties on their surfaces. This excellent uniformity can be attributed to two aspects: first, the effective dispersion and templating effect of nanocellulose on graphene avoids severe agglomeration of conductive fillers, ensuring extensive coverage of the conductive network; second, the relatively well-ordered ion channels potentially guided by the molecularly imprinted crosslinking agent result in more consistent and efficient charge dissipation on the material surface. In contrast, Comparative Example 4, lacking an effective filler dispersion mechanism, may not only have a higher resistivity value but also exhibit significant fluctuations between different test points, making accurate measurement difficult. This directly reflects the discontinuity and non-uniformity of its conductive network.

[0220] Furthermore, the antistatic properties of the samples from the embodiments of this invention exhibited better stability under slight temperature and humidity disturbances. Compared to the surface resistivity under initial conditions, the resistivity change of the samples after adjusting the temperature and humidity was relatively small. This indicates that the conductive network and ion conduction pathway constructed by the optimized material composition and preparation process of this invention have high robustness. Whether it is the physical conductive network formed by the nanocellulose / graphene composite filler or the ion conductive channels constructed with the assistance of molecularly imprinted crosslinking agents, the stability and continuity of the structure make the conductivity of the material less susceptible to significant influence from external environmental factors. This stability is crucial for ensuring that the cleanroom floor can continuously and effectively perform its antistatic function in actual use environments.

[0221] Test Example 3:

[0222] This test case aims to evaluate the impact of the "step-by-step curing process combining light pre-curing and thermal curing" used in this invention on the final physical and mechanical properties and chemical resistance of the coating by comparing the samples of Examples 1-3 with those of Comparative Example 3 (without the thermal curing step).

[0223] 1. Sample preparation:

[0224] All samples (Example 1, Example 2, Example 3, and Comparative Example 3) were prepared into coated samples according to their respective preparation methods. For Comparative Example 3, the curing process only included a light pre-curing step, without subsequent heat curing treatment.

[0225] The substrate for the samples can be a standard tinplate, glass plate, or treated concrete plate, depending on the requirements of the testing standards, to ensure that all comparison samples use the same substrate and thickness.

[0226] Before conducting any tests, all samples were conditioned for at least 7 days (or until performance was stable) under standard laboratory conditions (temperature 23±2℃, relative humidity 50±5%), unless otherwise specified in the specific standard.

[0227] 2. Physical and mechanical property testing of the coating:

[0228] 2.1 Pencil Hardness Test

[0229] Test standard: Refer to GB / T6739-2006 "Determination of paint film hardness by pencil method for paints and varnishes".

[0230] Sample: A coated sample applied to a flat, hard substrate.

[0231] Experimental steps:

[0232] 1. Select a set of standard test pencils (e.g., from 6B to 6H).

[0233] 2. Sharpen the pencil shaft to expose about 3mm of lead. Use 400-grit sandpaper to smooth the end face of the lead and make it perpendicular to the pencil axis.

[0234] 3. Place the coating sample on a hardness tester or on a horizontal platform.

[0235] 4. Apply a load of 750±10g (or the standard load) at an angle of about 45° to the coated surface and push it forward about 7mm.

[0236] 5. Gently erase the pencil marks with an eraser and observe the coating surface for scratches (meaning the coating is scratched or has permanent indentations).

[0237] 6. Start testing with a softer pencil and gradually increase the pencil hardness until you find a pencil hardness that can just scratch the coating. Record the hardness rating of the hardest pencil that did not scratch the coating as the pencil hardness of the paint film. Test at least 3 different locations for each sample and record the most frequent result.

[0238] 2.2 Adhesion test (cross-cut test) standard: Refer to GB / T9286-1998 "Cross-cut test of paint and varnish film".

[0239] Sample: A coating sample applied to a flat substrate.

[0240] Experimental steps:

[0241] 1. Using a dedicated multi-blade cutter or single-blade blade, make several parallel cuts perpendicular to each other on the coating surface, forming a grid pattern. The number and spacing of the cuts are selected based on the coating thickness and substrate type (for example, for a hard substrate coating less than 60 μm thick, typically 6 cuts are made with a 1 mm spacing). Ensure that the cuts penetrate the coating and reach the substrate.

[0242] 2. Use a soft-bristled brush to gently brush away any loose coating debris along the diagonal direction within the square area.

[0243] 3. Firmly adhere standard pressure-sensitive tape (such as tape conforming to ISO 2409) to the marked area, ensuring full contact between the tape and the coating.

[0244] 4. After the tape has been on for 1-5 minutes, peel it off smoothly and quickly at an angle of approximately 60°.

[0245] 5. Observe the peeling of the coating within the marked area and assess the adhesion level (from level 0 to level 5, with level 0 being the best and level 5 being the worst) with reference to the diagrams or descriptions in the standard. Test at least 3 different locations for each sample group.

[0246] 2.3 Abrasion resistance test (Taiber abrasion method) Test standard: Refer to GB / T1768-2006 "Determination of abrasion resistance of paints and varnishes - Rotating rubber wheel method" (equivalent to ASTM D4060).

[0247] Sample: Prepare circular or square coated samples with a central hole, conforming to the requirements of the Taibo abrasion tester.

[0248] Experimental steps:

[0249] 1. Install the prepared sample on the turntable of the Tiber abrasion tester.

[0250] 2. Select the appropriate abrasive wheel (e.g., CS-10 or CS-17) and load (e.g., 500g or 1000g).

[0251] 3. Before testing, pre-grind the grinding wheel according to standard requirements.

[0252] 4. Set the wear speed (e.g., 500 rpm, 1000 rpm) and start the instrument to perform the wear.

[0253] 5. After the wear is complete, remove the sample and clean the surface debris.

[0254] 6. Abrasion resistance can be assessed using one or more of the following methods:

[0255] Loss-in-weight method: Weigh the sample before and after wear and calculate the mass loss (mg / 100 rpm or mg / 1000 rpm).

[0256] Wear-through point: Record the number of revolutions required to wear through the coating and expose the substrate. (Optional) Haze or gloss loss: Measure the change in haze or gloss of the coating surface before and after wear.

[0257] 7. Each group of samples should be tested with at least two parallel samples.

[0258] 3. Chemical resistance test (MEK swab method):

[0259] Test standards: Refer to ASTM D4752-10 (2015) "Standard Test Method for Measuring MEK Resistance of Ethyl Silicate (Inorganic) Zinc-Rich Primers by Solvent Rub" or similar solvent wiping standards, and adjust according to the coating type.

[0260] Sample: A coated sample applied to a flat, inert substrate.

[0261] Experimental steps:

[0262] Fix the sample on a horizontal surface.

[0263] Use a pipette to take an appropriate amount of methyl ethyl ketone (MEK) and moisten the end of a clean cotton cloth or standard wiping cloth.

[0264] Wrap a damp cotton cloth around your finger (you can wear gloves) and rub the coated surface back and forth with about 1 kg of pressure (one back and forth motion counts as one rub). The rubbing distance should be about 5-8 cm.

[0265] Continue wiping until the coating shows obvious damage (such as dissolution, softening, or exposure of the substrate) or until the predetermined number of wipings is reached (e.g., 100 or 200 times).

[0266] Record the number of wiping cycles required to cause damage to the coating. If the coating remains intact after reaching the predetermined maximum number of wiping cycles, record it as ">Maximum Number of Wipes".

[0267] Each sample group was tested at least 3 different locations.

[0268] Table 3: Evaluation data on the influence of curing mechanism on the comprehensive physical and mechanical properties and stability of the coating

[0269]

[0270]

[0271] Experimental results strongly confirm the crucial role of the "stepwise curing process combining photocuring and thermal curing" employed in this invention in improving the overall physical and mechanical properties of the coating. Test data on pencil hardness, adhesion, and abrasion resistance show that the samples from this invention, treated with the complete stepwise curing process, exhibit significantly better performance than the sample from Comparative Example 3, which only underwent photocuring. This is mainly attributed to the fact that the silicone-modified epoxy acrylate prepolymer in this invention's system simultaneously contains photosensitive acrylic groups and heat-sensitive epoxy groups. During the photocuring stage, visible light initiates rapid free radical polymerization of the acrylic groups, forming a preliminary cross-linked network, which imparts initial shape stability and operational strength to the coating. However, relying solely on photocuring may limit the conversion rate of acrylic groups, and the epoxy groups essentially do not participate in the reaction, resulting in insufficient cross-linked network density and weaker overall mechanical properties, as demonstrated by the lower hardness, poorer adhesion, and susceptibility to abrasion exhibited in Comparative Example 3.

[0272] The subsequent thermosetting step is the core of constructing a high-performance coating. Under heated conditions, the epoxy groups in the system begin to undergo ring-opening polymerization and further react with other active groups that may be present in the prepolymer and crosslinking agent (such as the vinyl groups on the functional phosphoroimidazole ionic liquid monomer that were not fully reacted during the photocuring stage), forming a denser and more complete three-dimensional interpenetrating or covalently crosslinked network structure. Simultaneously, the heat energy also promotes the continued polymerization of acrylic groups that were not fully reacted during the photocuring stage, increasing the overall crosslinking density. This synergistic and stepwise reaction of photosensitive and thermosensitive groups results in a more complete and ordered formation of the polymer network, thereby endowing the coating with excellent mechanical strength, strong adhesion to the substrate, and resistance to external physical wear. The high pencil hardness, Grade 0 adhesion, and low abrasion weight loss of the example samples are direct manifestations of this highly crosslinked network structure.

[0273] Regarding chemical resistance, the results of the MEK wiping test clearly demonstrate the superiority of the stepwise synergistic curing process. The sample from this invention's embodiment withstood far more wiping cycles than the sample from Comparative Example 3 without damage, indicating stronger resistance to solvent erosion. This is also attributed to the further refinement and densification of the crosslinking network by the thermosetting step. A highly crosslinked polymer network effectively hinders the penetration and swelling of solvent molecules, thus protecting the coating structure from damage. Comparative Example 3, due to insufficient crosslinking and a loose network, allowed solvent molecules to easily penetrate and damage its structure, leading to rapid softening or dissolution. Therefore, the innovative stepwise curing mechanism employed in this invention, by fully utilizing the characteristics of different reactive groups in the prepolymer system, optimizes the polymer network structure, thereby comprehensively improving the physical and mechanical properties and chemical stability of the coating, meeting the requirements of harsh application environments for flooring materials.

[0274] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A flame-retardant and antistatic polymer coating material for cleanroom flooring, characterized in that, The following components are included by mass percentage: The functional phosphoryl imidazole ionic liquid monomer is 18.0-22.0%, wherein the ionic liquid monomer is 1-vinyl-3-methylimidazolium bis(2-methoxyethyl) phosphate, wherein the distance between the imidazole ring and the phosphate group is 3-5 atomic distances, the phosphate group is substituted with dialkoxy, and the vinyl group is located at the N1 position of the imidazole ring. Silicon-modified epoxy acrylate prepolymer: 45.0-48.0%, acrylic group density 0.8-1.2 mmol / g, epoxy group density 1.5-2.0 mmol / g, acrylic group to epoxy group density ratio 1.2:1-1.8:1, siloxane content 8.0-12.0%; The molecularly imprinted crosslinking agent is 9.0-11.0%, wherein the crosslinking agent is N,N'-bisacrylamidotriethyl phosphate, and the molar ratio of phosphorus atoms to acrylamide groups is 1:2; The nano-cellulose / graphene composite filler contains 5.0-7.0% of the material, with a graphene to cellulose mass ratio of 1:1.5-1:2.

5. The average particle size of the composite filler is 50-200 nm, and the graphene dispersion is greater than 0.

95. The photothermal synergistic initiator system comprises 3.0-4.0%, including 1.5-2.0% visible light-sensitive organic boron salt and 1.5-2.0% peroxide initiator; Functional additives 3.0-5.0%, including leveling agents, defoamers and ultraviolet absorbers; The molar ratio of the functional phosphoric imidazole ionic liquid monomer to the molecularly imprinted crosslinking agent is 3.2:1-4.8:1, the pH value of the system is 6.5-7.2, and the ratio of the total molar number of phosphorus element to the molar number of imidazole ring is 1.8:1-2.2:

1.

2. The flame-retardant and antistatic polymer coating material for cleanroom flooring according to claim 1, characterized in that, The functional phosphoroimidazole ionic liquid monomer has a water content of less than 0.2%, an acid value of less than 2 mg KOH / g, a vinyl substitution degree of more than 95% at the N1 position of the imidazole ring, and a dialkoxy substitution rate of 100% for the phosphate group.

3. The flame-retardant and antistatic polymer coating material for cleanroom flooring according to claim 1, characterized in that, The viscosity of the silicon-modified epoxy acrylate prepolymer at 25°C is 2000-5000 mPa·s, and the purity of the molecularly imprinted crosslinking agent is greater than 98%.

4. The flame-retardant and antistatic polymer coating material for cleanroom flooring according to claim 1, characterized in that, The specific surface area of ​​the nanocellulose / graphene composite filler is 150-300 m². 2 / g.

5. A method for preparing a flame-retardant and antistatic polymer coating material for cleanroom flooring according to any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Raw material pretreatment. The functional phosphoroimidazole ionic liquid monomer is placed in a rotary evaporator and dehydrated for 2.0-2.5 hours at 45-55℃ and a vacuum of 0.08-0.10MPa. After cooling to room temperature, it is stored under nitrogen protection. The graphene and cellulose in the nanocellulose / graphene composite filler are mixed at a mass ratio of 1:2.

0. 20% of the silicon-modified epoxy acrylate prepolymer is added as a dispersion medium. The mixture is treated by ultrasonic dispersion with an ultrasonic power of 200-300W, an ultrasonic frequency of 20-40kHz, and a treatment time of 30-45 minutes. The temperature is kept below 35℃ by ice bath cooling. Step 2: Staged mixing, carried out in a reaction vessel under nitrogen protection, in the following order: First stage: Mix the pretreated functionalized phosphoric imidazole ionic liquid monomer and silicon-modified epoxy acrylate prepolymer at a stirring speed of 200-300 rpm, temperature of 25±2℃, for 30-35 minutes; Second stage: Add pre-dispersed nanocellulose / graphene composite filler, stir for 15-20 minutes, then add the molecularly imprinted crosslinking agent at a stirring speed of 400-500 rpm for 20-25 minutes; Third stage: Add the photothermal synergistic initiator system under light-shielding conditions, followed by the functional additives, at a stirring speed of 150-200 rpm for 10-15 minutes; Then, perform vacuum degassing at a vacuum degree of 0.08-0.10 MPa for 15-20 minutes. Step 3: Substrate pretreatment and coating application. The substrate is mechanically sanded to a surface roughness of Ra 1.6-3.2μm, cleaned and dried until the moisture content is less than 4%, and then coated with a penetrating primer at a rate of 150-200g / m². 2 After drying for 4-6 hours, apply the coating material to a thickness of 2.0-3.0 mm using a microstructured coating head. The ambient temperature during application should be 20-25℃, and the relative humidity should be 45-65%. Step 4: Step-by-step curing. First, perform light pre-curing using a visible light LED light source with a wavelength of 450-470nm and a light intensity of 8-12mW / cm². 2 Curing time is 60-120 seconds, and the temperature is controlled below 30℃. After an interval of no more than 30 minutes, heat curing is carried out. The heating rate is 2-4℃ / min to raise the temperature to 60-80℃, and the temperature is kept for 2-4 hours. The temperature fluctuation is controlled within ±2℃. Step 5: Post-treatment, natural aging at room temperature for 24-48 hours, ambient temperature 20-25℃, relative humidity 50-60%.

6. The method for preparing a flame-retardant and antistatic polymer coating material for cleanroom flooring according to claim 5, characterized in that, In the raw material pretreatment step, the water content of the functional phosphoric imidazole ionic liquid monomer after dehydration treatment is less than 0.2%, the graphene dispersion of the nanocellulose / graphene composite filler after pretreatment is greater than 0.95, and the nitrogen flow rate during the staged mixing process is 100-200 mL / min.

7. The method for preparing a flame-retardant and antistatic polymer coating material for cleanroom flooring according to claim 5 or 6, characterized in that, After the phased mixing step is completed, quality control testing is performed. The viscosity of the mixture at 25°C is 800-1200 mPa·s, the pH value is 6.5-7.2, the solid content is 95-98%, and the gelation time is 45-65 minutes.

8. A method for preparing a flame-retardant and antistatic polymer coating material for cleanroom flooring according to any one of claims 5-7, characterized in that, In the light pre-curing step, the height of the LED light source is 150-200mm, the moving speed is 0.5-1.0m / min, and the target gel content is 40-60%. In the heat curing step, the cooling rate does not exceed 5℃ / min, and the target gel content is 85-95%.

9. A method for preparing a flame-retardant and antistatic polymer coating material for cleanroom flooring according to any one of claims 5-8, characterized in that, In the substrate pretreatment step, mechanical sanding uses 80-120 grit sandpaper with a sanding depth of 0.5-1.0 mm, cleaning uses 5-10% industrial cleaning agent with a cleaning time of 10-15 minutes, and drying temperature of 40-60℃.

10. A method for preparing a flame-retardant and antistatic polymer coating material for cleanroom flooring according to any one of claims 5-9, characterized in that, In the post-processing steps, dust protection is maintained during the natural aging process to avoid direct sunlight. After aging, the surface is finished by lightly sanding with 400-600 grit sandpaper to remove surface defects. After sanding, the surface dust is cleaned with a lint-free cloth, and the surface flatness is controlled within ±2mm / 2m.

Images