Intelligent sensing halogen-free flame-retardant resin coating for wood as well as preparation method and application of intelligent sensing halogen-free flame-retardant resin coating

Abstract

The invention discloses an intelligent sensing halogen-free flame-retardant resin coating for wood as well as a preparation method and application of the intelligent sensing halogen-free flame-retardant resin coating, and belongs to the technical field of wood functional coating materials. The coating comprises the following raw materials: a deionized water component, a universal acrylic monomer component, a special acrylic monomer component, a halogen-free flame-retardant component, an emulsifier component and an initiator component. The preparation method of the coating comprises the following steps: by taking tannic acid as a core, firstly constructing a nitrogen-phosphorus-based composite system under the synergistic effect of the tannic acid, polyethyleneimine and phosphoric acid; then metal nickel is further complexed, polypyrrole is subjected to in-situ polymerization to jointly construct a halogen-free flame-retardant component, polyacrylate is prepared through emulsion polymerization, and the active early-warning multifunctional flame-retardant coating which is low in expansion and high in compactness is constructed. According to the technology, integration of fire early warning, efficient flame retardance and base material protection is achieved, a new material design strategy and a new technical path are provided for safe and durable application of wood, and the application prospect is wide.

Description

Technical Field

[0001] This invention belongs to the technical field of functional coating materials for wood, specifically relating to a smart sensing halogen-free flame-retardant resin coating for wood, its preparation method, and its application. Background Technology

[0002] Timber, with its excellent processability, economic efficiency, and sustainable use, is of great significance for environmental protection and reducing dependence on fossil fuels. However, the inherent flammability of timber poses serious safety hazards. Building fires often spiral out of control due to small initial fires spreading rapidly through the wood, resulting in significant casualties and property damage. Therefore, developing surface coating technologies that are tailored to the characteristics of timber and possess both highly effective flame retardant and fire warning functions has become an urgent need to ensure the safe application of timber.

[0003] Traditional wood flame retardant technology initially relied on halogenated inorganic flame retardants. While achieving high efficiency through gas-phase free radical capture, these methods suffered from problems such as releasing toxic gases, poor adhesion to wood, and easy migration. With the popularization of "halogen-free" and "green chemistry" concepts, nitrogen-phosphorus flame retardants have become mainstream due to their superior flame retardant performance and low smoke efficiency. Nitrogen-phosphorus flame retardant coatings are divided into non-intumescent and intumescent types. The former can block heat and oxygen but is thick and lacks flexibility; the latter expands upon heating to form a porous char layer, resulting in better combustible gas release. However, intumescent coatings face significant challenges when applied to wood. Their dramatic volume expansion at high temperatures clashes with the thermal contraction of wood, easily leading to coating peeling and surface cracking, severely damaging their flame retardant effect and substrate integrity. Furthermore, intumescent coatings are mostly inorganic, resulting in insufficient adhesion to wood and weak long-term stability. More importantly, existing flame retardant technologies almost entirely focus on passively inhibiting or delaying the combustion process, severely lacking proactive early warning capabilities for initial fire stages.

[0004] For example, CN104311725A discloses a flame-retardant polyacrylate emulsion and its preparation method. The flame-retardant polyacrylate emulsion, by weight percentage, consists of 30.0-45.0% acrylate monomer, 1.0-6.0% reactive flame-retardant monomer, 0.5-3.0% emulsifier (OP), 0.5-1.0% initiator, 35.0-65.0% deionized water, and 2.0-11.0% antimony compounds. The preparation method involves first pre-emulsifying the reactive flame retardant and acrylate monomer, then performing emulsion seed polymerization. After seed polymerization, the remaining pre-emulsion and initiator are added dropwise. The reaction is carried out at 78-85℃ for 5-8 hours, then heated to 90-95℃ for 30-60 minutes. After cooling and filtration, antimony compounds are added and stirred until homogeneous to obtain the flame-retardant polyacrylate emulsion.

[0005] For example, CN106142254A discloses a process for preparing a halogen-free flame retardant water-based agent that can rapidly penetrate wood, comprising: adding methyl phosphate, solvent and alkaline catalyst to a three-necked flask, heating and adding acrylamide, refluxing for 2-3 hours, adjusting the pH to 7-7.7 with acetic acid, and obtaining methyl (3-amino-3-acylpropyl)phosphonate after the reaction, wherein the catalyst is a non-acidic compound of alkaline earth metal; reacting the methyl (3-amino-3-acylpropyl)phosphonate with formaldehyde under alkaline conditions for 2-3 hours to obtain N-hydroxymethyl-3-(methoxyphosphoryl)propionamide.

[0006] Existing halogen-free flame-retardant coating technologies for wood have significant deficiencies in terms of mechanical compatibility, environmental stability, and functional integrity. Developing a new coating system that can coordinate "halogen-free high-efficiency flame retardancy - active fire warning - long-term substrate compatibility" has become a key breakthrough in solving the problem of safe application of wood. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the primary objective of this invention is to provide a smart sensing halogen-free flame-retardant resin coating for wood prepared via a polyphenol-mediated functional integration method, eliminating halogen components. This invention also provides a method for preparing the smart sensing halogen-free flame-retardant resin coating for wood.

[0008] Another objective of this invention is to provide an application of a smart sensing halogen-free flame-retardant resin coating for wood, applicable to fields such as building materials (wooden structural components, engineered wood panels, plywood, MDF, and particleboard, etc.), furniture and home furnishings (solid wood / commercial furniture, wooden daily necessities), transportation and outdoor facilities (wooden interior materials for transportation, garden landscape facilities), packaging and logistics (wooden packaging for export), and electronic and electrical auxiliary materials. Its water-based system has good compatibility with wood, meets environmental protection and flame-retardant standards in multiple industries, and is particularly suitable for scenarios with close contact with people, enclosed spaces, and high environmental compliance requirements.

[0009] To address the problems existing in the prior art and achieve the technical objectives of this invention, this invention is based on a "polyphenol-mediated" method, using tannic acid as the core. First, it synergistically combines tannic acid with polyethyleneimine and phosphoric acid to construct a nitrogen-phosphorus-based composite system. Then, it further complexes with metallic nickel and in-situ polymerized polypyrrole to construct a halogen-free flame-retardant component (TPPNy). Through intermolecular interactions, it composites with polyacrylate to construct a "low-expansion, high-density" active warning multifunctional flame-retardant coating, TPSA. In terms of the flame-retardant mechanism, TPSA releases flame-retardant gases during combustion while simultaneously forming a dense carbon layer, achieving effective flame retardancy and providing a carbon-based framework for conductivity. The polypyrrole on the in-situ polymerized TPPNy releases inert gases and enhances the continuity of the carbon layer, making the carbon-based conductive network more complete. Ni in the coating... 2+Under high flame temperatures, the carbon layer oxidizes to NiO, which acts as an inorganic conductive phase to fill the gaps in the carbon layer, further enhancing the continuity of the conductive network and reducing "conductive breakpoints." Simultaneously, under flame catalysis, a more robust "metal-carbon" composite char layer is formed, improving flame retardancy and anti-dripping capabilities. This low-expansion coating formed after combustion effectively avoids conflict with the thermal deformation stress of the wood, and its high density ensures the char layer's ability to remain conductive and not collapse under long-term heat radiation. This achieves an integration of "fire warning - high-efficiency flame retardancy - substrate protection," providing a new material design strategy and technical approach for the safe and durable application of wood.

[0010] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows: A smart sensing halogen-free flame-retardant resin coating for wood comprises the following raw materials in parts by weight: 90.0-100.0 parts of deionized water, 80.0-100.0 parts of general-purpose acrylic monomers, 5.0-10.0 parts of special-purpose acrylic monomers, 1.0-5.0 parts of halogen-free flame-retardant component TPNy, 1.0-2.0 parts of emulsifier, and 0.2-1.2 parts of initiator.

[0011] Preferably, the intelligent sensing halogen-free flame-retardant resin coating for wood comprises the following raw materials in parts by weight: 90.0 parts of deionized water component, 100.0 parts of general-purpose acrylic monomer component, 8.0 parts of special-purpose acrylic monomer component, 1.0-5.0 parts of halogen-free flame-retardant component, 1.5 parts of emulsifier component, and 0.4 parts of initiator component.

[0012] Preferably, the general-purpose acrylic monomer component is one or more of butyl acrylate, isooctyl acrylate, styrene, acrylonitrile, and methyl methacrylate.

[0013] More preferably, the general-purpose acrylic monomer component is a combination of butyl acrylate, isooctyl acrylate and acrylonitrile.

[0014] Preferably, the special type of acrylic monomer component is one or more of acrylic acid, methacrylic acid, glycidyl methacrylate, hydroxyethyl acrylate, and N-hydroxyethylacrylamide.

[0015] More preferably, the special type of acrylic monomer component is a combination of acrylic acid and N-hydroxyethylacrylamide.

[0016] Preferably, the halogen-free flame retardant component is constructed by polyphenol-mediated, tannic acid-based, synergistic interaction with polyethyleneimine and phosphoric acid to form a nitrogen-phosphorus composite system; then, it is further complexed with metallic nickel and in-situ polymerized with polypyrrole to jointly construct the halogen-free flame retardant component (TPPNy). The preparation method of the halogen-free flame retardant component TPNy is as follows: (1) In a container, add 30.0 kg of tannic acid and deionized water to prepare an aqueous solution with a mass concentration of 20.0%, heat and stir in a water bath at 60°C for 1 h; then add 30.0 kg of polyethyleneimine (Mw≈10000) and react for 2 h. After the reaction is completed, raise the temperature to 80°C and slowly add 15.0 kg of phosphoric acid prepared into an aqueous solution with a mass concentration of 50% to the container over 1 h. After the addition is completed, continue to keep the temperature and react for 1 h, then cool to room temperature, centrifuge, wash with anhydrous ethanol, and vacuum dry to obtain the product TPP; (2) The obtained TPP was dispersed in deionized water to prepare a dispersion with a mass concentration of 10%, and then ultrasonically dispersed for 30 min. After that, it was placed in a water bath at 60℃ and stirred. Then, 10.0 kg of nickel chloride hexahydrate was prepared into a 5% aqueous solution and stirred until dissolved. Under vigorous stirring, NiCl2 solution was slowly added dropwise to the TPP dispersion, the temperature was maintained at 60℃ and the pH of the system was adjusted to 5.0-6.0 with 0.1 mol / L NaOH solution, and the reaction was continued for 3 h. After the reaction was completed, the solution was cooled to room temperature, then centrifuged, washed with anhydrous ethanol and vacuum dried to obtain the product TPPN. (3) Prepare a 10% mass concentration dispersion of dried TPPN with deionized water; slowly add 10.0 kg of pyrrole to the dispersion and stir for 30 min under ice bath conditions to form a uniform dispersion system; prepare a 10% mass concentration aqueous solution of 5.0 kg of ammonium persulfate with deionized water and add it dropwise to the uniform mixture of TPPN and pyrrole under ice bath conditions, and react for 12 h; filter the obtained product and then centrifuge, wash with anhydrous ethanol, and vacuum dry to obtain the halogen-free flame retardant component TPPNy.

[0017] Preferably, the emulsifier is a reactive emulsifier, specifically including one or a combination of 1-allyloxy-3-(4-nonylphenol)-2-propanol polyoxyethylene (10) ether ammonium sulfate (DNS86), sodium vinyl sulfonate (SVS), castor oil polyoxyethylene ether (EL-10), and allyloxy isomeric alcohol ether sulfate ammonium salt (SR-10).

[0018] More preferably, the emulsifier component is allyloxyisomeric alcohol ether sulfate ammonium salt SR-10.

[0019] Preferably, the initiator is one or a combination of ammonium persulfate, potassium persulfate, and sodium persulfate.

[0020] More preferably, the initiator is an aqueous solution of ammonium persulfate with a mass concentration of 25%.

[0021] A method for preparing a smart sensing halogen-free flame-retardant resin coating for wood includes the following preparation steps: (1) Add 1 part of emulsifier component and 40 parts of deionized water to the pre-emulsification reactor, stir evenly, then add the initiator and stir for 5 minutes. Then add the general-purpose acrylic monomer to the pre-emulsification reactor and stir evenly. Then add the special-purpose acrylic monomer and pre-emulsify for 60 minutes to obtain the pre-emulsion. (2) Next, add the remaining deionized water and emulsifier to the polymerization reactor, stir evenly and heat to 88°C. Add the pre-emulsion dropwise over 4 hours. 30 minutes before the end of the pre-emulsion addition, slowly add the halogen-free flame retardant component TPNy as a 30% mass concentration aqueous dispersion to the polymerization reactor. After the remaining emulsion is added, keep the reaction at 88°C for 2 hours. Then, cool down to 40-50°C and adjust the pH to 7-8 with ammonia. Filter the final emulsion through a 180-mesh filter to obtain the final product, halogen-free flame retardant resin coating TPSAs.

[0022] Beneficial effects: (1) This invention synthesizes the flame-retardant component TPNy using a "polyphenol-mediated" method. An aqueous polyacrylic acid resin emulsion is prepared via emulsion polymerization. TPNy is then combined with polyacrylate through intermolecular interactions to form a stable, halogen-free flame-retardant resin coating for intelligent sensing in wood applications. In terms of the flame-retardant mechanism, TPNy releases flame-retardant gases upon combustion and simultaneously forms a dense carbon layer, achieving effective flame retardancy and providing a carbon-based framework for electrical conductivity. The polypyrrole polymerized in situ releases inert gases and enhances the continuity of the carbon layer, making the carbon-based conductive network more complete. Ni in the coating... 2+ Under high flame temperatures, the carbon layer oxidizes to NiO, which acts as an inorganic conductive phase to fill the gaps between carbon layers, further enhancing the continuity of the conductive network and reducing "conductive breakpoints." Simultaneously, under flame catalysis, a more robust "metal-carbon" composite char layer is formed, improving flame retardancy and anti-dripping capabilities. This composite low-expansion coating avoids conflict with the thermal deformation stress of wood, and its high density ensures the char layer's ability to remain conductive and not collapse under long-term heat radiation. This achieves an integration of "fire warning - high-efficiency flame retardancy - substrate protection," providing a new material design strategy and technical approach for the safe and durable application of wood.

[0023] (2) The intelligent sensing halogen-free flame-retardant resin coating for wood involved in this invention can meet the needs of different application fields by optimizing and controlling the ratio and composition of raw materials.

[0024] (3) The intelligent sensing halogen-free flame-retardant resin coating for wood involved in this invention does not involve organic solvents such as halogens, acetone, and xylene, and no other small organic molecules are released during the curing process. It is green and environmentally friendly and has broad application prospects. Attached Figure Description

[0025] Figure 1 This is the synthesis circuit for the halogen-free flame retardant component in an embodiment of the present invention; Figure 2This invention provides a synthesis circuit for halogen-free intelligent sensing and halogen-free flame-retardant resin for wood. Figure 3 The image shows a vertical combustion test of the resin coating in Example 4 of the present invention (a) and SEM images at different scales after combustion (b). Figure 4 The diagrams shown are from Example 4 of the present invention, which are obtained by cone calorimeter testing of halogen-free intelligent sensing halogen-free wood flame-retardant resin. (a) shows the temperature change of wood at different combustion stages over time; (b) shows the total heat release rate of the flame-retardant coating in Example 4 over time; (c) shows the smoke production rate of the flame-retardant coating in Example 4 over time; (d) shows the total smoke production rate of the flame-retardant coating in Example 4 over time; (e) shows the char rate of the flame-retardant coating in Example 4 over time; and (f) shows the heat release rate of the flame-retardant coating in Example 4 over time. Figure 5 The diagram shows the electrical conductivity of the halogen-free intelligent sensing flame-retardant resin for wood in Example 4 of the present invention. Diagram a shows the electrical conductivity of the coated wood in Example 4 under flame for 10 seconds, and diagram b shows the electrical conductivity of the coated wood in Example 4 after flameout and subsequent reignition. Detailed Implementation

[0026] The technical solution of the present invention will be further described below with reference to specific embodiments, but it is not limited thereto.

[0027] Example 1 Synthetic halogen-free flame retardant component TPNy: (1) In a container, add 30.0 kg of tannic acid and deionized water to prepare an aqueous solution with a mass concentration of 20.0%, heat and stir in a water bath at 60°C for 1 h; then add 30.0 kg of polyethyleneimine (Mw≈10000) and react for 2 h. After the reaction is completed, raise the temperature to 80°C and slowly add 15.0 kg of phosphoric acid prepared into an aqueous solution with a mass concentration of 50% to the container over 1 h. After the addition is completed, continue to keep the temperature and react for 1 h, then cool to room temperature, centrifuge, wash with anhydrous ethanol, and vacuum dry to obtain the product TPP; (2) The obtained TPP was dispersed in deionized water to prepare a dispersion with a mass concentration of 10%, and then ultrasonically dispersed for 30 min. After that, it was placed in a water bath at 60℃ and stirred. Then, 10.0 kg of nickel chloride hexahydrate was prepared into a 5% aqueous solution and stirred until dissolved. Under vigorous stirring, NiCl2 solution was slowly added dropwise to the TPP dispersion, the temperature was maintained at 60℃ and the pH of the system was adjusted to 5.0-6.0 with 0.1 mol / L NaOH solution, and the reaction was continued for 3 h. After the reaction was completed, the solution was cooled to room temperature, then centrifuged, washed with anhydrous ethanol and vacuum dried to obtain the product TPPN. (3) The dried TPPN was prepared into a 10% (w / w) dispersion using deionized water; 10.0 kg of pyrrole was slowly added dropwise to the dispersion, and the mixture was stirred for 30 min under ice bath conditions to form a uniform dispersion system; 5.0 kg of ammonium persulfate was prepared into a 10% (w / w) aqueous solution using deionized water, and added dropwise to the uniform mixture of TPPN and pyrrole under ice bath conditions, and the reaction was carried out for 12 h; the obtained product was filtered, centrifuged, washed with anhydrous ethanol, and vacuum dried to obtain the halogen-free flame retardant component TPPNy. The preparation methods of the halogen-free flame retardant component TPPNy in other embodiments are the same as in Example 1. The synthetic route is as follows: Figure 1 As shown.

[0028] A method for preparing a smart sensing halogen-free flame-retardant resin coating for wood includes the following preparation steps: 1.0 kg of allyloxyisomeric alcohol ether sulfate ammonium salt (SR-10) and 40.0 kg of deionized water were added to a pre-emulsification reactor and stirred until homogeneous. Then, 0.4 kg of a 25% ammonium persulfate solution was added and stirred for another 5 minutes. Next, 20.0 kg of butyl acrylate, 30.0 kg of isooctyl acrylate, and 50.0 kg of acrylonitrile from general-purpose acrylic monomers were added to the pre-emulsification reactor and stirred until homogeneous. Then, 4.0 kg of acrylic acid and 4.0 kg of N-hydroxyethyl acrylamide from special-purpose acrylic monomers were added and pre-emulsified for 60 minutes to obtain a pre-emulsion. Then, 50.0 kg of deionized water and 0.5 kg of emulsifier were added to a polymerization reactor and stirred until homogeneous. The temperature was raised to 88°C, and the pre-emulsion was added dropwise over 4 hours. 30 minutes before the end of the pre-emulsion addition, 1.0 kg of TPPNy, prepared as a 30% aqueous solution, was slowly added to the polymerization reactor. After the remaining emulsion is added, the reaction is carried out at 88℃ for 2 hours. Then, the temperature is lowered by 40-50℃ and the pH value is adjusted to 7-8 with ammonia. The final emulsion is then filtered through a 180-mesh filter to obtain the intelligent sensing halogen-free wood flame retardant resin coating (TPSA1).

[0029] This application prepares an aqueous polyacrylic acid resin emulsion via emulsion polymerization using methacrylic acid, butyl acrylate, isooctyl acrylate, acrylonitrile, N-hydroxyethyl acrylamide, and a halogen-free flame retardant component (TPPNy). The resulting intelligent sensing halogen-free flame retardant resin coating, formed by the intermolecular forces of TPNy and its composite with polyacrylate, has the structure of formula (Ⅰ): The synthetic route is as follows: Figure 2 As shown.

[0030] Example 2 The halogen-free flame retardant component TPPNy was prepared using the same method as in Example 1.

[0031] A method for preparing a smart sensing halogen-free flame-retardant resin coating for wood includes the following preparation steps: 1.0 kg of allyloxyisomeric alcohol ether sulfate ammonium salt (SR-10) and 40.0 kg of deionized water were added to a pre-emulsification reactor and stirred until homogeneous. Then, 0.4 kg of 25% ammonium persulfate solution was added and stirred for another 5 min. Next, 20.0 kg of butyl acrylate, 30.0 kg of isooctyl acrylate, and 50.0 kg of acrylonitrile from general-purpose acrylic monomers were added to the pre-emulsification reactor and stirred until homogeneous. Then, 4.0 kg of acrylic acid and 4.0 kg of N-hydroxyethyl acrylamide from special-purpose acrylic monomers were added and pre-emulsified for 60 min to obtain a pre-emulsion. Then, 50.0 kg of deionized water and 0.5 kg of emulsifier were added to a polymerization reactor and stirred until homogeneous. The temperature was raised to 88°C, and the pre-emulsion was added dropwise over 4 h. 30 min before the end of the pre-emulsion addition, 2.0 kg of TPPNy, prepared as a 30% aqueous dispersion, was slowly added to the polymerization reactor. After the remaining emulsion is added, the reaction is carried out at 88℃ for 2 hours. Then, the temperature is lowered by 40-50℃ and the pH value is adjusted to 7-8 with ammonia. The final emulsion is then filtered through a 180-mesh filter to obtain the intelligent sensing halogen-free wood flame retardant resin coating (TPSA2).

[0032] Example 3 The halogen-free flame retardant component TPPNy was prepared using the same method as in Example 1.

[0033] A method for preparing a smart sensing halogen-free flame-retardant resin coating for wood includes the following preparation steps: 1.0 kg of allyloxyisomeric alcohol ether sulfate ammonium salt (SR-10) and 40.0 kg of deionized water were added to a pre-emulsification reactor and stirred until homogeneous. Then, 0.4 kg of 25% ammonium persulfate solution was added and stirred for another 5 min. Next, 20.0 kg of butyl acrylate, 30.0 kg of isooctyl acrylate, and 50.0 kg of acrylonitrile from general-purpose acrylic monomers were added to the pre-emulsification reactor and stirred until homogeneous. Then, 4.0 kg of acrylic acid and 4.0 kg of N-hydroxyethyl acrylamide from special-purpose acrylic monomers were added and pre-emulsified for 60 min to obtain a pre-emulsion. Then, 50.0 kg of deionized water and 0.5 kg of emulsifier were added to a polymerization reactor and stirred until homogeneous. The temperature was raised to 88°C, and the pre-emulsion was added dropwise over 4 h. 30 min before the end of the pre-emulsion addition, 3.0 kg of TPPNy prepared as a 30% aqueous dispersion was slowly added to the polymerization reactor. After the remaining emulsion is added, the reaction is carried out at 88℃ for 2 hours. Then, the temperature is lowered by 40-50℃ and the pH value is adjusted to 7-8 with ammonia. The final emulsion is then filtered through a 180-mesh filter to obtain the intelligent sensing halogen-free wood flame retardant resin coating (TPSA3).

[0034] Example 4 The halogen-free flame retardant component TPPNy was prepared using the same method as in Example 1.

[0035] A method for preparing a smart sensing halogen-free flame-retardant resin coating for wood includes the following preparation steps: 1.0 kg of allyloxyisomeric alcohol ether sulfate ammonium salt (SR-10) and 40.0 kg of deionized water were added to a pre-emulsification reactor and stirred until homogeneous. Then, 0.4 kg of 25% ammonium persulfate solution was added and stirred for another 5 min. Next, 20.0 kg of butyl acrylate, 30.0 kg of isooctyl acrylate, and 50.0 kg of acrylonitrile from general-purpose acrylic monomers were added to the pre-emulsification reactor and stirred until homogeneous. Then, 4.0 kg of acrylic acid and 4.0 kg of N-hydroxyethyl acrylamide from special-purpose acrylic monomers were added and pre-emulsified for 60 min to obtain a pre-emulsion. Then, 50.0 kg of deionized water and 0.5 kg of emulsifier were added to a polymerization reactor and stirred until homogeneous. The temperature was raised to 88°C, and the pre-emulsion was added dropwise over 4 h. 30 min before the end of the pre-emulsion addition, 4.0 kg of TPPNy prepared as a 30% aqueous dispersion was slowly added to the polymerization reactor. After the remaining emulsion is added, the reaction is carried out at 88℃ for 2 hours. Then, the temperature is lowered by 40-50℃ and the pH value is adjusted to 7-8 with ammonia. The final emulsion is then filtered through a 180-mesh filter to obtain the intelligent sensing halogen-free wood flame retardant resin coating (TPSA4).

[0036] Example 5 The halogen-free flame retardant component TPPNy was prepared using the same method as in Example 1.

[0037] A method for preparing a smart sensing halogen-free flame-retardant resin coating for wood includes the following preparation steps: 1.0 kg of allyloxyisomeric alcohol ether sulfate ammonium salt (SR-10) and 40.0 kg of deionized water were added to a pre-emulsification reactor and stirred until homogeneous. Then, 0.4 kg of 25% ammonium persulfate solution was added and stirred for another 5 min. Next, 20.0 kg of butyl acrylate, 30.0 kg of isooctyl acrylate, and 50.0 kg of acrylonitrile from general-purpose acrylic monomers were added to the pre-emulsification reactor and stirred until homogeneous. Then, 4.0 kg of acrylic acid and 4.0 kg of N-hydroxyethyl acrylamide from special-purpose acrylic monomers were added and pre-emulsified for 60 min to obtain a pre-emulsion. Then, 50.0 kg of deionized water and 0.5 kg of emulsifier were added to a polymerization reactor and stirred until homogeneous. The temperature was raised to 88°C, and the pre-emulsion was added dropwise over 4 h. 30 min before the end of the pre-emulsion addition, 5.0 kg of TPPNy prepared as a 30% aqueous dispersion was slowly added to the polymerization reactor. After the remaining emulsion is added, the reaction is carried out at 88℃ for 2 hours. Then, the temperature is lowered by 40-50℃ and the pH value is adjusted to 7-8 with ammonia. The final emulsion is then filtered through a 180-mesh filter to obtain the intelligent sensing halogen-free wood flame-retardant resin coating (TPSA5).

[0038] Example 6 The halogen-free flame retardant component TPPNy was prepared using the same method as in Example 1.

[0039] A method for preparing a smart sensing halogen-free flame-retardant resin coating for wood includes the following preparation steps: 0.5 kg of allyloxyisomeric alcohol ether sulfate ammonium salt (SR-10) and 40.0 kg of deionized water were added to a pre-emulsification reactor and stirred until homogeneous. Then, 0.2 kg of 25% ammonium persulfate solution was added and stirred for another 5 min. Next, 20.0 kg of butyl acrylate, 30.0 kg of isooctyl acrylate, and 30.0 kg of acrylonitrile from the general-purpose acrylic monomers were added to the pre-emulsification reactor and stirred until homogeneous. Then, 2.5 kg of acrylic acid and 2.5 kg of N-hydroxyethyl acrylamide from the special-purpose acrylic monomers were added and pre-emulsified for 60 min to obtain a pre-emulsion. Then, 60.0 kg of deionized water and 0.5 kg of emulsifier were added to the polymerization reactor and stirred until homogeneous. The temperature was raised to 88°C, and the pre-emulsion was added dropwise over 4 h. 30 min before the end of the pre-emulsion addition, 4.0 kg of TPPNy prepared as a 30% aqueous dispersion was slowly added to the polymerization reactor. After the remaining emulsion is added, the reaction is carried out at 88℃ for 2 hours. Then, the temperature is lowered by 40-50℃ and the pH value is adjusted to 7-8 with ammonia. The final emulsion is then filtered through a 180-mesh filter to obtain the intelligent sensing halogen-free wood flame-retardant resin coating (TPSA6).

[0040] Example 7 The halogen-free flame retardant component TPPNy was prepared using the same method as in Example 1.

[0041] A method for preparing a smart sensing halogen-free flame-retardant resin coating for wood includes the following preparation steps: 1 kg of allyloxyisomeric alcohol ether sulfate ammonium salt (SR-10) and 40.0 kg of deionized water were added to a pre-emulsification reactor and stirred until homogeneous. Then, 1.2 kg of 25% ammonium persulfate solution was added and stirred for another 5 min. Next, 20.0 kg of butyl acrylate, 30.0 kg of isooctyl acrylate, and 40.0 kg of acrylonitrile from general-purpose acrylic monomers were added to the pre-emulsification reactor and stirred until homogeneous. Then, 5 kg of acrylic acid and 5 kg of N-hydroxyethyl acrylamide from special-purpose acrylic monomers were added and pre-emulsified for 60 min to obtain a pre-emulsion. Then, 40.0 kg of deionized water and 1 kg of emulsifier were added to a polymerization reactor and stirred until homogeneous. The temperature was raised to 88°C, and the pre-emulsion was added dropwise over 4 h. 30 min before the end of the pre-emulsion addition, 5.0 kg of TPPNy prepared as a 30% aqueous dispersion was slowly added to the polymerization reactor. After the remaining emulsion is added, the reaction is carried out at 88℃ for 2 hours. Then, the temperature is lowered by 40-50℃ and the pH value is adjusted to 7-8 with ammonia. The final emulsion is then filtered through a 180-mesh filter to obtain the intelligent sensing halogen-free wood flame retardant resin coating (TPSA7).

[0042] Comparative Example 1 A method for preparing a flame-retardant resin includes the following steps: 1.0 kg of allyloxyisomeric alcohol ether sulfate ammonium salt (SR-10) and 40.0 kg of deionized water are added to a pre-emulsification reactor and stirred evenly. Then, 0.4 kg of ammonium persulfate with a mass concentration of 25% is added and stirred for 5 min. Then, 20.0 kg of general-purpose acrylic monomers, 30.0 kg of isooctyl acrylate and 50.0 kg of acrylonitrile are added to the pre-emulsification reactor and stirred evenly. Then, 4.0 kg of special-purpose acrylic monomers, 4.0 kg of acrylic acid and 4.0 kg of N-hydroxyethyl acrylamide are added and pre-emulsified for 60 min. Next, 50.0 kg of deionized water and 0.5 kg of emulsifier are added to a polymerization reactor and stirred evenly. The temperature is raised to 88°C. The pre-emulsified liquid is dripped into the polymerization reactor over 4 h. After the remaining emulsion is added, the reaction is carried out at 88℃ for 2 hours. Then, the temperature is lowered by 40-50℃ and the pH value is adjusted to 7-8 with ammonia. The final emulsion is then filtered through a 180-mesh filter to obtain waterborne polyacrylic acid resin (PSA).

[0043] Comparative Example 2 A method for preparing waterborne polyacrylic resin with added TPP flame retardant component includes the following steps: 1.0 kg of allyloxyisomeric alcohol ether sulfate ammonium salt (SR-10) and 40.0 kg of deionized water are added to a pre-emulsification reactor and stirred evenly. Then, 0.4 kg of ammonium persulfate with a mass concentration of 25% is added and stirred for 5 min. Then, 20.0 kg of general-purpose acrylic monomers, 30.0 kg of isooctyl acrylate and 50.0 kg of acrylonitrile are added to the pre-emulsification reactor and stirred evenly. Then, 4.0 kg of special-purpose acrylic monomers, 4.0 kg of acrylic acid and 4.0 kg of N-hydroxyethyl acrylamide are added and pre-emulsified for 60 min. Next, 50.0 kg of deionized water and 0.5 kg of emulsifier are added to a polymerization reactor and stirred evenly. The temperature is raised to 88°C and the pre-emulsified liquid is added dropwise over 4 h. Thirty minutes before the end of the pre-emulsion addition, 4.0 kg of TPP (TPP synthesis method is the same as in Example 1) was slowly added to the polymerization reactor as a 30% (w / w) aqueous dispersion. After the remaining emulsion was added, the reaction was maintained at 88°C for 2 hours, then cooled to 40-50°C, and the pH was adjusted to 7-8 with ammonia. The final emulsion was then filtered through a 180-mesh filter to obtain halogen-free wood flame retardant resin (pPSA).

[0044] Comparative Example 3 A common method for preparing waterborne polyacrylate resin with bromine-antimony flame retardant components includes the following steps: 1.0 kg of epoxy polyoxyethylene ammonium sulfate (SR-10) and 40 kg of deionized water are added to a pre-emulsification reactor and stirred evenly. Then, 0.4 kg of 25% ammonium persulfate is added and stirred for another 5 min. Next, 20.0 kg of general-purpose acrylic monomers, 30.0 kg of isooctyl acrylate and 50.0 kg of acrylonitrile are added to the pre-emulsification reactor and stirred evenly. Then, 4.0 kg of special-purpose acrylic monomers, 4.0 kg of acrylic acid and 4.0 kg of N-hydroxyethyl acrylamide are added and pre-emulsified for 60 min. Then, 50.0 kg of deionized water and 0.5 kg of emulsifier are added to a polymerization reactor and stirred evenly. The temperature is raised to 88°C. The pre-emulsified liquid is dripped into the polymerization reactor over 4 h. After the remaining emulsion is added dropwise, the reaction is kept at 88℃ for 2 hours. Then, the temperature is lowered to 40-50℃ and the pH is adjusted to 7-8 with ammonia. Then, 1.0 kg of decabromodiphenyl ethane and 2.0 kg of antimony trioxide are added to the polymerization flask and stirred for another 0.5 hours. Finally, the emulsion is filtered through a 180-mesh filter to obtain a halogen-containing waterborne polyacrylic acid resin (hPSA).

[0045] Performance testing This application relates to a smart sensing halogen-free flame-retardant wood resin, which is based on traditional water-based polyacrylate resins. By introducing the flame-retardant component TPNy, a "low-expansion, high-density" active warning multifunctional flame-retardant wood coating is designed. Examples and comparative examples are provided for comparison. First, the coating was prepared according to the examples and comparative methods. Five samples were repeated for each experimental group, and the results were averaged. Viscosity was tested using a digital rotational viscometer (rotor No. 2, 60 rmp / min) according to GB / T2794-2022 "Determination of Viscosity of Adhesives". Solid content was determined by accurately weighing the initial mass m0 (g) of a clean, dry petri dish, and then weighing m1 (g) of sample (1.0~2.0 g) into it. The petri dish was heat-treated in a 110 ℃ oven for 2 h to remove volatile moisture, and then transferred to a vacuum oven for negative pressure cooling to room temperature. After cooling, the mass m2 (g) of the petri dish was weighed again. The solid content was calculated using the formula: (m2− m0) / m1× 100%. After the reaction, the prepared TPSA was filtered through a 180-mesh filter. The gel collected on the filter was placed in an oven at 110 °C for 1 hour, and then weighed (m1, g). The gel amount was calculated as: m1 / m0 × 100%. In the formula, m0 is the sum of the masses of all monomers. The emulsion to be tested was diluted 1000 times with deionized water, and its particle size (nm) was measured using a dynamic light scattering (DLS) instrument at room temperature (25 °C). The physicochemical properties of the prepared coating were tested, and the results are shown in Table 1.

[0046] Table 1 Basic physicochemical properties of each sample Based on the physical properties data in Table 1, Example 4 (TPPNy addition of 4 kg) is the optimal solution among all systems. Its viscosity of 328.3 mPa·s and particle size of 137.3 nm are within a reasonable range, meeting the rheological requirements for coating with wood flame-retardant resin without causing excessive viscosity or a surge in particle size due to intermolecular aggregation. The solid content reaches 48.5%, which is significantly higher than that of Examples 1-3 (45.2%-47.2%), demonstrating the effective combination of TPNy in optimizing the proportion of effective components in the system. At the same time, the gel rate is only 0.48%, maintaining a low level of cross-linking and aggregation, and the stability remains unchanged for 6 months without stratification. In contrast, although Example 5 has a slightly higher solid content, the gel rate increases to 1.27% and the stability decreases to 3 months, revealing the aggregation risk caused by excessive TPNy. Compared with Example 1 (blank system), the solid content is only 44.5%, and the functional components are missing. Compared with Example 2 (TPP replacement), the performance is similar but there are no intelligent sensing characteristics. Compared with Example 3 (halogen-containing system), although stable, it does not conform to the halogen-free environmental protection orientation.

[0047] Meanwhile, the intelligent sensing halogen-free wood flame retardant resin of this invention is mainly applied to the flame retardant surface of wood. Its flame retardant ability test mainly includes: (1) cone calorimeter test according to GB / T 34749-2017 "Test Method for Fire Resistance of Wood and Wood Composite Materials - Cone Calorimeter Method"; (2) limiting oxygen index (LOI) test according to GB / T 17658-1999 "Test Method for Combustion Performance of Flame Retardant Wood - Oxygen Index Method"; (3) vertical burning test according to GB / T 8626-2007 "Test Method for Combustibility of Building Materials".

[0048] Table 2. Test results of the cone calorimeter Table 3. Flame retardancy and anti-dripping test results Combining the flame retardant performance test results in Tables 2 and 3, it can be seen that the introduction of TPNy has a significant regulatory effect on the flame retardant performance of the wood flame retardant coating: the heat release rate of the blank system in Comparative Example 1 is as high as 1754.9 kW / m², the limiting oxygen index (LOI) is only 18.1%, and it does not self-extinguish during combustion and has no smoke production or char formation inhibition effect; while as the amount of TPNy in the examples increases, the heat release rate gradually decreases from 1171.4 kW / m² in Example 1 to 311.2 kW / m² in Example 5, the CO2 release and smoke production rate decrease simultaneously, the residual char content increases from 21.5% to 56.4%, the LOI increases from 19.7% to 39.8%, and the self-extinguishing time after removal from the flame is shortened from "not self-extinguishing" to 3s. At the same time, it has anti-dripping ability, which shows that TPNy enhances flame retardancy by promoting char formation and inhibiting heat / smoke release.

[0049] In comparison, Comparative Example 2, which uses the traditional halogen-free flame retardant TPP, has a heat release rate of 412.1 kW / m², an LOI of 30.4%, and a self-extinguishing time of 10 s, which is weaker than Example 4, which adds 4 kg of TPPNy. Comparative Example 3, with its halogen-containing system, achieves an LOI of 42.3% and a self-extinguishing time of 3 s, but its smoke production rate is 2.21 m² / s and it lacks anti-dripping properties; furthermore, the halogen-containing component does not conform to environmental protection guidelines. Example 4, with a heat release rate of 396.4 kW / m², a smoke production rate of 0.11 m² / s, a carbon residue of 52.1%, an LOI of 34.1%, and a self-extinguishing time of 3 s, achieves low heat release, low smoke hazard, and effective flame retardancy in a halogen-free system, while avoiding the physical stability risks caused by excessive TPPPNy in Example 5. It is the optimal solution that balances flame retardancy, environmental friendliness, and practical value.

[0050] Figure 3The images show the vertical combustion test and post-combustion SEM images of the halogen-free intelligent sensing halogen-free wood flame-retardant resin in Example 4 of this invention. The images demonstrate that the TPSA4 coating exhibits significant flame-retardant properties. After ignition, the flame spreads slowly, and after 30 seconds of continuous ignition, it self-extinguishes within 3 seconds of being removed from the flame, with no dripping generated throughout the process. This proves that the introduction of TPNy not only effectively delays combustion but also eliminates the risk of dripping ignition. Simultaneously, the SEM images show that the char residue from the TPSA4 coating exhibits a denser, porous network structure with expanded protrusions. This improved morphology is mainly due to the synergistic flame-retardant mechanism of "acid source-char source-gas source" integrated by TPNy: phosphate groups act as an acid source, catalyzing the dehydration and cross-linking of polymer components to form a char layer framework; nitrogen- / oxygen-containing groups act as a gas source, decomposing upon heating to release non-combustible gases, promoting char layer expansion; and nickel acts as a catalyst, promoting further cross-linking and aromatization of the char layer, enhancing its density and thermal stability. This indicates that the char layer formed by TPSA4 during combustion has an effective flame-retardant effect on wood, further verifying that the char layer induced by TPNy has excellent thermal stability and long-term flame-retardant ability, laying a material foundation for the coating to provide continuous protection in real fires. Figure 4 This is a cone calorimeter test diagram of halogen-free intelligent sensing halogen-free wood flame-retardant resin in Embodiment 4 of the present invention. Figure 4 The diagrams shown are from the cone calorimeter test of the halogen-free intelligent sensing halogen-free wood flame-retardant resin in Example 4 of this invention. (a) shows the temperature change of wood at different combustion stages over time; (b) shows the total heat release rate of the flame-retardant coating in Example 4 over time; (c) shows the smoke production rate of the flame-retardant coating in Example 4 over time; (d) shows the total smoke production rate of the flame-retardant coating in Example 4 over time; (e) shows the char residue rate of the flame-retardant coating in Example 4 over time; and (f) shows the heat release rate of the flame-retardant coating in Example 4 over time. It can be seen that the TPSA4 coating exhibits a low heat release rate difference, low smoke production rate, and a stable char residue skeleton under 50 kW / m² thermal radiation. These three properties are actually the core mechanism for achieving excellent flame-retardant effects. They work synergistically to block the combustion process from three dimensions: "inhibiting heat release," "reducing toxic fumes," and "maintaining structural integrity."

[0051] Based on the conductivity test results in Table 4, a 0.3mm thick flame-retardant coating was applied to a 2cm thick wooden substrate at 6V. A regulated DC voltage was connected to a pre-reserved interface, and the current change was recorded by burning the coating surface with a flame. Comparing Example 1 (blank system), Example 2 (TPP flame-retardant system), and Example 3 (traditional bromine-antimony halogen-containing flame-retardant system), it was found that without the introduction of TPNY components, a carbon-based conductive framework could not be formed based on TPNY, and the continuity of the carbon layer reinforced by polypyrrole and Ni were also lacking. 2+The high-temperature oxidation process results in NiO filling the gaps between carbon layers, thus neither exhibits any electrical conductivity, and neither electrical response nor conductivity continuity indicators are reflected.

[0052] As the amount of TPNy in the examples was gradually increased from 1.0 kg to 5.0 kg, its conductivity was significantly improved. Example 1 (TPPNy) Although 1.0 kg of TPNY initially formed a carbon-based framework, the limited amount resulted in insufficient synergy between polypyrrole and NiO, poor continuity of the carbon layer and gap filling effect, and an electrical response time as long as 62 s and a conductivity continuity of only 2 s. In Example 3, the amount of TPNY was increased, the continuity of the carbon layer and the degree of NiO filling were improved, the electrical response time was shortened to 15 s and the conductivity continuity was extended to 23 s. By Example 4, the carbon-based framework of TPNY, the carbon layer reinforcement effect of polypyrrole and the gap filling effect of NiO had fully synergized to construct a complete "metal-carbon" composite conductive network. The electrical response time was reduced to 9 s and the conductivity continuity reached 80 s, which was on par with the conductivity performance of Example 5. This not only confirms the key regulatory role of the amount of TPNY in the construction of the conductive network, but also highlights that Example 4 can ensure optimal conductivity while taking into account the comprehensive adaptation of physical stability and flame retardant performance. Figure 5 The conductive properties of the halogen-free intelligent sensing halogen-free wood flame-retardant resin in Example 4 of this invention are shown in the figure. It can be seen that the current begins to appear in the wood coated with TPSA4 after approximately 10 seconds of flame burning, and a stable signal is formed within 60 seconds, confirming that it can sense thermal stimuli in real time through electrical changes. The mechanism lies in the fact that during combustion, TA and PPy in TPNY act as carbon sources, undergoing cross-linking and carbonization to form a dense carbon skeleton rich in conjugated structures (phosphoric acid catalyzed densification, low expansion ensuring integrity); PPy, as an intrinsically conductive polymer, further enhances the continuity of the carbon layer, conforming to the description of the formation of continuous conductive pathways in the "conductive channel theory".

[0053] Table 4. Conductivity Test Results Therefore, this study used the amount of TPNy as the core control variable, combined with multi-dimensional testing of physical properties, flame retardant performance, and intelligent conductivity, to clarify that Example 4, with an TPNy addition of 4 kg, is the optimal system for comprehensive performance of intelligent sensing halogen-free wood flame retardant resin. In terms of physical properties, the viscosity (328.3 mPa.s) and particle size (137.3 nm) of Example 4 are suitable for the rheological requirements of wood coatings, with a significantly increased solid content (48.5%), low gelation rate, and stability of up to 6 months without stratification. This avoids the defects of insufficient functional components at low dosages and the risk of aggregation caused by excessive TPNy. Regarding flame retardant performance, this system achieves low heat release rate (396.4 kW / m²), low smoke production rate (0.11 m² / s), high residual carbon content (52.1%), and a 3s... It exhibits rapid self-extinguishing, outperforming traditional halogen-free TPP systems while eliminating the environmental drawbacks of halogen-containing systems, achieving a balance between high-efficiency flame retardancy and environmental friendliness. Regarding intelligent conductivity, Example 4 utilizes a "carbon-based framework-polypyrrole reinforcement-NiO filler" composite network constructed with TPNy, achieving a 9s electrical response time and 80s conductivity continuity. It is the only system simultaneously possessing stable physical state, high-efficiency halogen-free flame retardancy, and reliable intelligent sensing capabilities. Example 1, while possessing some flame retardancy, uses a smaller amount of TPNy, potentially failing to achieve continuous carbon layer formation, resulting in weaker overall performance. Example 4 is the preferred embodiment of this invention.

[0054] It should be noted that the above embodiments are merely some preferred embodiments of the present invention, and not all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

Claims

1. A smart sensing halogen-free flame-retardant resin coating for wood, characterized in that, The raw materials include the following parts by weight: 90.0-100.0 parts of deionized water, 80.0-100.0 parts of general-purpose acrylic monomers, 5.0-10.0 parts of special-purpose acrylic monomers, 1.0-5.0 parts of halogen-free flame retardant TPNy, 1.0-2.0 parts of emulsifier, and 0.2-1.2 parts of initiator.

2. The intelligent sensing halogen-free flame-retardant resin coating for wood according to claim 1, characterized in that, The raw materials include the following parts by weight: 90.0 parts deionized water, 100.0 parts general-purpose acrylic monomers, 8.0 parts special-purpose acrylic monomers, 4.0 parts halogen-free flame retardant, 1.5 parts emulsifier, and 0.4 parts initiator.

3. The intelligent sensing halogen-free flame-retardant resin coating for wood according to claim 2, characterized in that, The general-purpose acrylic monomer components are one or more of butyl acrylate, isooctyl acrylate, styrene, acrylonitrile, and methyl methacrylate.

4. The intelligent sensing halogen-free flame-retardant resin coating for wood according to claim 3, characterized in that, The general-purpose acrylic monomer component is a combination of butyl acrylate, isooctyl acrylate, and acrylonitrile.

5. The intelligent sensing halogen-free flame-retardant resin coating for wood according to claim 2, characterized in that, The special type of acrylic monomer component is one or more of acrylic acid, methacrylic acid, glycidyl methacrylate, hydroxyethyl acrylate, and N-hydroxyethylacrylamide.

6. The intelligent sensing halogen-free flame-retardant resin coating for wood according to claim 5, characterized in that, The special type of acrylic monomer component is a combination of acrylic acid and N-hydroxyethylacrylamide.

7. The intelligent sensing halogen-free flame-retardant resin coating for wood according to claim 2, characterized in that, The preparation method of the halogen-free flame retardant component TPNy is as follows: (1) In a container, add 30.0 kg of tannic acid and deionized water to prepare an aqueous solution with a mass concentration of 20.0%, heat and stir in a water bath at 60°C for 1 h; then add 30.0 kg of polyethyleneimine and react for 2 h. After the reaction is completed, raise the temperature to 80°C and slowly add 15.0 kg of phosphoric acid to prepare an aqueous solution with a mass concentration of 50% over 1 h. After the addition is completed, continue to keep the temperature and react for 1 h, then cool to room temperature, centrifuge, wash with anhydrous ethanol, and vacuum dry to obtain the product TPP; (2) The obtained TPP was dispersed in deionized water to prepare a dispersion with a mass concentration of 10%, and then ultrasonically dispersed for 30 min. After that, it was placed in a water bath at 60℃ and stirred. Then, 10.0 kg of nickel chloride hexahydrate was prepared into a 5% aqueous solution and stirred until dissolved. Under vigorous stirring, NiCl2 solution was slowly added dropwise to the TPP dispersion, the temperature was maintained at 60℃ and the pH of the system was adjusted to 5.0-6.0 with 0.1 mol / L NaOH solution, and the reaction was continued for 3 h. After the reaction was completed, the solution was cooled to room temperature, then centrifuged, washed with anhydrous ethanol and vacuum dried to obtain the product TPPN. (3) Prepare a 10% mass concentration dispersion of dried TPPN with deionized water; slowly add 10.0 kg of pyrrole to the dispersion and stir for 30 min under ice bath conditions to form a uniform dispersion system; prepare a 10% mass concentration aqueous solution of 5.0 kg of ammonium persulfate with deionized water and add it dropwise to the uniform mixture of TPPN and pyrrole under ice bath conditions, and react for 12 h; filter the obtained product and then centrifuge, wash with anhydrous ethanol, and vacuum dry to obtain the halogen-free flame retardant component TPPNy.

8. The intelligent sensing halogen-free flame-retardant resin coating for wood according to claim 2, characterized in that, The emulsifier component is allyloxyisomeric alcohol ether sulfate ammonium salt SR-10, and the initiator is an aqueous solution of ammonium persulfate with a mass concentration of 25%.

9. A method for preparing a smart sensing halogen-free flame-retardant resin coating for wood according to any one of claims 1-8, characterized in that, The preparation steps include the following: (1) Add 1 part of emulsifier component and 40 parts of deionized water to the pre-emulsification reactor, stir evenly, then add the initiator, stir for 5 minutes, then add the general-purpose acrylic monomer to the pre-emulsification reactor and stir evenly, then add the special-purpose acrylic monomer, pre-emulsify for 60 minutes to obtain the pre-emulsified liquid. (2) Next, add the remaining deionized water and emulsifier to the polymerization reactor, stir evenly and heat to 88°C. Add the pre-emulsion dropwise over 4 hours. 30 minutes before the pre-emulsion is finished, slowly add the halogen-free flame retardant component TPNy as a 30% water dispersion to the polymerization reactor. After the remaining emulsion is added, keep the reaction at 88°C for 2 hours. Then, cool down to 40-50°C and adjust the pH to 7-8 with ammonia. Filter the final emulsion through a 180-mesh filter to obtain the final product, halogen-free flame retardant resin coating.

10. The application of the intelligent sensing halogen-free flame-retardant resin coating for wood according to any one of claims 1-8, characterized in that, It is used in building materials, furniture, transportation, outdoor facilities, packaging and logistics, and electronic and electrical auxiliary materials.

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