Water-based ultra-thin wood fire-retardant paint, preparation method and application thereof

Abstract

The application discloses water-based super-thin wood fire-retardant paint and a preparation method and application thereof, and preparation raw materials comprise water-based acrylic emulsion, fire retardant and Fe-MOFs synergist; preparation raw materials of the Fe-MOFs synergist comprise metal iron salt, organic ligand and silane coupling agent.The application provides water-based super-thin wood fire-retardant paint, which has excellent fire-retardant performance, can rapidly form an effective isolation layer in a high-temperature environment, and significantly inhibits the spread of fire.Meanwhile, the super-thin design of the paint significantly reduces the usage amount, and meets the urgent needs of modern industry and building fields for light weight, high efficiency and environmental protection.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a water-based ultra-thin flame-retardant coating for wood, its preparation method, and its application. Background Technology

[0002] Wood, as a renewable natural material, is favored for its unique properties and wide range of applications. Compared to traditional concrete and metal materials, wood offers superior finishing effects and is cleaner and more environmentally friendly. Furthermore, wood's excellent visual, tactile, auditory, and olfactory properties, as well as its regulatory functions, have led to its widespread use in furniture, construction, and interior decoration. However, wood's flammability is a major limitation to its widespread application and also poses a potential threat to people's lives and property. Traditional wood flame-retardant treatment processes are complex and time-consuming, typically requiring the wood to be completely or partially immersed in flame retardants to ensure the flame-retardant components penetrate deep into the wood fibers, thereby improving its flame-retardant performance. Subsequently, an additional coating is applied to enhance surface protection and durability. This process is not only inefficient but may also diminish the natural charm and visual appeal of the wood. Moreover, with increasing environmental awareness and increasingly stringent regulations, traditional solvent-based wood flame-retardant coatings face challenges due to their high VOC emissions and environmental pollution problems. Summary of the Invention

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a water-based ultra-thin flame-retardant coating for wood. This coating not only possesses excellent flame-retardant properties, rapidly forming a barrier layer at high temperatures to effectively suppress fire, but its ultra-thin coating design also significantly reduces the amount of coating used, meeting the urgent needs of modern industry and construction for lightweight, high-efficiency, and environmentally friendly materials.

[0004] The present invention also proposes a method for preparing a water-based ultra-thin flame-retardant coating for wood.

[0005] This invention also proposes the application of water-based ultra-thin flame-retardant wood coatings in the field of decoration.

[0006] According to one aspect of the present invention, a water-based ultra-thin flame-retardant coating for wood is provided, the raw materials for preparation including: water-based acrylic emulsion, flame retardant and Fe-MOFs synergist;

[0007] The raw materials for preparing the Fe-MOFs synergist include: iron salts, organic ligands, and silane coupling agents.

[0008] This invention uses Fe-MOFs materials as synergists. Due to their abundant Fe content, the derived iron oxides exhibit excellent catalytic oxidation and carbonization activities, thereby promoting the substrate's ability to catalytically form carbon during degradation and obtaining a highly graphitized, dense carbon layer. Simultaneously, Fe-MOFs possess a high specific surface area and abundant porous structure, enabling them to adsorb smoke nuclei, smoke particles, and toxic and harmful gases generated during combustion.

[0009] This invention uses silane coupling agents to modify Fe-MOFs materials, which improves their compatibility and dispersibility, and at the same time improves their flame retardant performance through the synergistic flame retardancy of silicon.

[0010] The water-based ultra-thin wood flame-retardant coating prepared by the method described in this invention has good adhesion, impact resistance, flexibility, water resistance, temperature and heat resistance, and excellent fire-retardant properties.

[0011] In some embodiments of the present invention, the flame retardant includes phosphorus-based flame retardants and phosphorus-nitrogen-based flame retardants.

[0012] In some embodiments of the present invention, the silane coupling agent includes an aminosilane coupling agent.

[0013] Silane coupling agents are a class of amphoteric substances. Some groups in their molecules can react with chemical groups on the surface of inorganic materials to form strong chemical bonds, while other groups have organophilic properties, reacting with or physically entangled with organic molecules. This allows them to firmly bond two materials with different properties, thereby improving their dispersibility, compatibility, and interfacial interactions. Furthermore, the combustion of silane coupling agents generates a dense and stable silicon-containing (mainly SiO2) carbon layer. This silicon-containing carbon layer not only prevents the escape of flammable substances from combustion decomposition but also acts as a heat and oxygen barrier, preventing the thermal decomposition of polymer materials and achieving flame retardancy, low smoke, and low toxicity.

[0014] In some embodiments of the present invention, the aminosilane coupling agent includes at least one of KH550 and KH792.

[0015] In some embodiments of the present invention, the raw materials for preparation include, by weight: 45-70 parts of aqueous acrylic emulsion, 20-35 parts of flame retardant, and 2-6 parts of Fe-MOFs synergist.

[0016] In some embodiments of the present invention, the raw materials for preparation also include: expanded perlite.

[0017] On the one hand, the Fe-MOFs synergist modified with silane coupling agent can not only form covalent bonds with the hydroxyl groups on the surface of expanded perlite through the reaction of silane groups, but also the nitrogen functional groups in the aminosilane coupling agent can form chemical bonds with the surface hydroxyl groups (-OH) and iron ions (Fe3+) of Fe-MOFs. Since Fe-MOFs have rich pore structure and high specific surface area, the aminosilane coupling agent can be more uniformly distributed and form a larger range of chemical bonding with the surface of expanded perlite. At the same time, the long-chain molecular structural units at the other end of the aminosilane coupling agent can chemically crosslink or physically entangle with polymer molecules, which ultimately significantly improves the compatibility and dispersibility of Fe-MOFs and expanded perlite with polymers.

[0018] On the other hand, MIL-101(Fe) has strong adsorption capacity and high specific surface area. When MIL-101(Fe) covers the surface of expanded perlite, during the heating process, the MIL-101(Fe) coating the surface of expanded perlite releases the adsorbed moisture or other volatile gases, providing more expansion power for expanded perlite and promoting faster expansion of expanded perlite at relatively low temperatures. The coating made from this material quickly forms a barrier layer in a high-temperature environment, effectively suppressing the fire and realizing the design of an ultra-thin coating.

[0019] On the other hand, due to the catalytic graphitization of Fe-MOFs and the rapid expansion of expanded perlite, an expanded and dense flame-retardant carbon layer is formed, which can effectively prevent the transfer of heat and oxygen, thus achieving the purpose of flame retardancy and heat insulation.

[0020] In some embodiments of the present invention, the raw materials for preparation further include: additives.

[0021] In some embodiments of the present invention, the additives include: film-forming aids, defoamers, thickeners, and wetting agents.

[0022] In some embodiments of the present invention, the film-forming aid includes at least one of propylene glycol methyl ether PM, propylene glycol butyl ether PnB, dipropylene glycol methyl ether DPM, and dipropylene glycol butyl ether DPNB.

[0023] In some embodiments of the present invention, the defoamer includes at least one of TEGO-800, TEGO805, TEGO-810, TEGO-815, TEGO-825, BYK-019, and BYK-020.

[0024] In some embodiments of the present invention, the thickener includes at least one of the following: nonionic polyurethane associative thickener RM-8W, hydrophobically modified alkali-swellable associative thickener TT-935, alkali-swellable nonassociative thickener ASE-60, nonionic associative thickener TEGO ViscoPlus 3000, TEGO ViscoPlus 3030, and TEGO ViscoPlus 3060.

[0025] In some embodiments of the present invention, the wetting agent is at least one of polyether siloxane copolymer TEGO-245, nonionic organic surfactant TEGO-500, and polyether modified polysiloxane solution BYK-346.

[0026] In some embodiments of the present invention, the raw materials for preparation, by weight, include: 45-70 parts of aqueous acrylic emulsion, 20-35 parts of flame retardant, 2-6 parts of Fe-MOFs synergist, 2-6 parts of film-forming aid, 0.1-0.3 parts of defoamer, 0.1-1 parts of thickener, and 0.1-0.5 parts of wetting agent.

[0027] In some embodiments of the present invention, the raw materials for preparation further include water, by weight.

[0028] According to a second aspect of the present invention, a method for preparing a water-based ultra-thin flame-retardant coating for wood is provided, comprising: mixing and reacting the raw materials for preparing the water-based ultra-thin flame-retardant coating for wood.

[0029] In some embodiments of the present invention, the preparation method of the Fe-MOFs synergist includes:

[0030] A1. Fe-MOFs material is obtained by first microwave heating the dispersion of the metal iron salt and the organic ligand;

[0031] A2. The Fe-MOFs synergist is obtained by dispersing the Fe-MOFs material and silane coupling agent and then reacting them with microwave heating for a second time.

[0032] In some embodiments of the present invention, the molar ratio of the iron salt to the organic ligand is 3 to 5:3.

[0033] In some embodiments of the present invention, step A1, the dispersion step, further includes the addition of a solvent.

[0034] In some embodiments of the present invention, the molar ratio of the iron salt, the organic ligand, and the solvent is 3-5:3:200-400.

[0035] In some embodiments of the present invention, the temperature of the first microwave heating reaction is 110–160°C.

[0036] In some embodiments of the present invention, the duration of the first microwave heating reaction is 20 to 180 minutes.

[0037] Microwave synthesis of MOFs is characterized by rapid reaction speed and small crystal size. The rapid and uniform heating of microwaves is beneficial for the synthesis process. The shorter reaction time and uniform temperature distribution reduce the chance of particle growth, allowing the generated particles to remain at the nanoscale. Nanoscale MOF materials possess many unique properties and application potential. For example, they have a large specific surface area, providing more active sites; simultaneously, nanoscale MOF materials exhibit good catalytic performance. These properties can all improve flame retardant properties. The microwave-synthesized nano-Fe-MOFs of this invention can significantly improve flame retardant properties; only a very small amount (≤6%) of nano-Fe-MOFs is needed to significantly reduce the combustion performance of the material while simultaneously improving its strength and toughness.

[0038] According to a third aspect of the present invention, the application of water-based ultra-thin flame-retardant wood coatings in the field of decoration is proposed. Detailed Implementation

[0039] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0040] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0041] Unless otherwise specified, "room temperature" in this invention means 25℃±5℃.

[0042] Unless otherwise specified, "about" in this invention means that the allowable error is within ±2%.

[0043] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0044] The first aspect of the present invention provides a water-based ultra-thin flame-retardant coating for wood, the raw materials for which include: water-based acrylic emulsion, flame retardant and Fe-MOFs synergist;

[0045] The raw materials for preparing the Fe-MOFs synergist include: iron salts, organic ligands, and silane coupling agents.

[0046] The embodiments employ Fe-MOFs materials as synergists. Due to their abundant Fe content, the derived iron oxides exhibit excellent catalytic oxidation and carbonization activities, thereby promoting the substrate's ability to catalytically form carbon during degradation and obtaining a highly graphitized, dense carbon layer. Simultaneously, Fe-MOFs possess a high specific surface area and abundant porous structure, enabling them to adsorb smoke nuclei, smoke particles, and toxic and harmful gases generated during combustion.

[0047] In the embodiments, silane coupling agents are a class of substances with an amphoteric structure. Some groups in their molecules can react with chemical groups on the surface of inorganic materials to form strong chemical bonds, while other groups have organophilic properties, reacting with or physically entangled with organic molecules. This allows them to firmly bond two materials with different properties, thereby improving their dispersibility, compatibility, and interfacial interactions. Furthermore, the combustion of silane coupling agents generates a dense and stable silicon-containing (mainly SiO2) carbon layer. This silicon-containing carbon layer not only prevents the escape of flammable substances from combustion decomposition but also acts as a heat and oxygen barrier, preventing the thermal decomposition of polymer materials and achieving the goals of flame retardancy, low smoke, and low toxicity.

[0048] A second aspect of the present invention provides a method for preparing a water-based ultra-thin flame-retardant coating for wood, comprising: mixing and reacting the raw materials for preparing the water-based ultra-thin flame-retardant coating for wood.

[0049] In some embodiments of the present invention, the preparation method of the Fe-MOFs synergist includes:

[0050] A1. Fe-MOFs material is obtained by first microwave heating the dispersion of the metal iron salt and the organic ligand;

[0051] A2. The Fe-MOFs synergist is obtained by dispersing the Fe-MOFs material and silane coupling agent and then reacting them with microwave heating for a second time.

[0052] Microwave synthesis of MOFs is characterized by rapid reaction speed and small crystal size. The rapid and uniform heating of microwaves is beneficial for the synthesis process. The shorter reaction time and uniform temperature distribution reduce the chance of particle growth, allowing the generated particles to remain at the nanoscale. Nanoscale MOF materials possess many unique properties and application potential. For example, they have a large specific surface area, providing more active sites; simultaneously, nanoscale MOF materials exhibit good catalytic performance. These properties can all improve flame retardant properties. The microwave-synthesized nano-Fe-MOFs of this invention can significantly improve flame retardant properties; only a very small amount (≤6%) of nano-Fe-MOFs is needed to significantly reduce the combustion performance of the material while simultaneously improving its strength and toughness.

[0053] A third aspect of the present invention provides the application of water-based ultra-thin flame-retardant wood coatings in the field of decoration.

[0054] Example 1

[0055] This embodiment provides a water-based ultra-thin flame-retardant coating for wood:

[0056] The product comprises the following components by weight: 65 parts of aqueous acrylic emulsion, 5 parts of FR-125 flame retardant, 20 parts of FT-6501 flame retardant, 5 parts of MIL-101(Fe) synergist, 3 parts of propylene glycol butyl ether film-forming aid, 0.1 parts of TEGO-815 defoamer, 0.3 parts of TT-935 thickener, 0.2 parts of TEGO-500 wetting agent, and 1.4 parts of deionized water;

[0057] This embodiment also provides a method for preparing a water-based ultra-thin flame-retardant coating for wood:

[0058] Synergist and flame retardant are added sequentially to water-based acrylic emulsion, followed by film-forming aid, defoamer, thickener and wetting agent. The mixture is dispersed for 10-30 minutes, filtered, and discharged to obtain water-based ultra-thin wood flame retardant coating.

[0059] The preparation method of the above-mentioned MIL-101(Fe) synergist is as follows: FeCl3·6H2O (a metallic iron salt), terephthalic acid (H2BDC) (an organic ligand), and phytic acid are added to a microwave reactor containing dimethylformamide (DMF) solvent, wherein the molar ratio of FeCl3·6H2O, H2BDC, phytic acid, and DMF is 4:2:1:320. The mixture is then magnetically stirred for 20 min, microwaved at 110℃ for 1 h, and cooled to room temperature. The reaction products are then centrifuged, washed with ethanol, and vacuum dried sequentially to obtain the MIL-101(Fe) material. Subsequently, the MIL-101(Fe) material and silane coupling agent KH550 are added to a 90% ethanol aqueous solution, wherein the mass ratio of MIL-101(Fe), KH550, and the ethanol aqueous solution is 1:2:30. The mixture is microwaved at 50℃ for 30 min, then centrifuged and dried to obtain the MIL-101(Fe) synergist.

[0060] Example 2

[0061] This embodiment provides a water-based ultra-thin flame-retardant coating for wood:

[0062] The product comprises the following components by weight: 70 parts of aqueous acrylic emulsion, 22 parts of FT-6500F flame retardant, 3 parts of MIL-100(Fe) synergist, 3 parts of propylene glycol butyl ether film-forming aid, 0.1 parts of TEGO-815 defoamer, 0.3 parts of TT-935 thickener, 0.2 parts of TEGO-500 wetting agent, and 1.4 parts of deionized water;

[0063] This embodiment also provides a method for preparing a water-based ultra-thin flame-retardant coating for wood:

[0064] Synergist and flame retardant are added sequentially to water-based acrylic emulsion, followed by film-forming aid, defoamer, thickener and wetting agent. The mixture is dispersed for 10-30 minutes, filtered, and discharged to obtain water-based ultra-thin wood flame retardant coating.

[0065] Metallic iron salt Fe(NO3)3·9H2O, organic ligand trimesolic acid (H3BTC), and phytic acid were added to a microwave reactor containing deionized water, with the molar ratio of Fe(NO3)3·9H2O, H3BTC, phytic acid, and H2O being 3:2:1:300. The mixture was then magnetically stirred for 20 min, microwaved at 150°C for 1 h, and cooled to room temperature. The reaction products were then centrifuged, washed with ethanol, and vacuum dried to obtain MIL-100(Fe) material. Subsequently, MIL-100(Fe) material and silane coupling agent KH550 were added to a 90% ethanol aqueous solution, with the mass ratio of MIL-100(Fe), KH550, and the ethanol aqueous solution being 1:2:30. The mixture was microwaved at 50°C for 30 min, centrifuged, and dried to obtain the MIL-100(Fe) synergist.

[0066] Example 3

[0067] This embodiment provides a water-based ultra-thin flame-retardant coating for wood:

[0068] The product comprises the following components by weight: 65 parts of aqueous acrylic emulsion, 22 parts of TZ-600C flame retardant, 4 parts of AP435 flame retardant, 3 parts of MIL-101(Fe) synergist, 2 parts of propylene glycol butyl ether film-forming aid, 0.3 parts of TEGO-815 defoamer, 0.2 parts of TT-935 thickener, 0.2 parts of TEGO-500 wetting agent, and 3.3 parts of deionized water;

[0069] This embodiment also provides a method for preparing a water-based ultra-thin flame-retardant coating for wood:

[0070] Synergist and flame retardant are added sequentially to water-based acrylic emulsion, followed by film-forming aid, defoamer, thickener and wetting agent. The mixture is dispersed for 10-30 minutes, filtered, and discharged to obtain water-based ultra-thin wood flame retardant coating.

[0071] The preparation method of the above-mentioned MIL-101(Fe) synergist is as follows: FeCl3·6H2O (a metallic iron salt), terephthalic acid (H2BDC) (an organic ligand), and phytic acid are added to a microwave reactor containing dimethylformamide (DMF) solvent, wherein the molar ratio of FeCl3·6H2O, H2BDC, phytic acid, and DMF is 4:2:1:320. The mixture is then magnetically stirred for 20 min, microwaved at 110℃ for 1 h, and cooled to room temperature. The reaction products are then centrifuged, washed with ethanol, and vacuum dried sequentially to obtain the MIL-101(Fe) material. Subsequently, the MIL-101(Fe) material and silane coupling agent KH550 are added to a 90% ethanol aqueous solution, wherein the mass ratio of MIL-101(Fe), KH550, and the ethanol aqueous solution is 1:2:30. The mixture is microwaved at 50℃ for 30 min, then centrifuged and dried to obtain the MIL-101(Fe) synergist.

[0072] Example 4

[0073] This embodiment provides a water-based ultra-thin flame-retardant coating for wood:

[0074] The composition by weight is as follows: 65 parts of water-based acrylic emulsion, 22 parts of TZ-600C flame retardant, 4 parts of AP435 flame retardant, 3 parts of MIL-101(Fe) synergist, 5 parts of expanded perlite, 2 parts of propylene glycol butyl ether film-forming aid, 0.3 parts of TEGO-815 defoamer, 0.2 parts of TT-935 thickener, 0.2 parts of TEGO-500 wetting agent, and 3.3 parts of deionized water;

[0075] This embodiment also provides a method for preparing a water-based ultra-thin flame-retardant coating for wood:

[0076] S1. The synergist, expanded perlite and deionized water were mixed and dispersed at 30 Hz and 150 W for 8 min to obtain a mixture;

[0077] S2. Slowly add the mixture to the water-based acrylic emulsion, then add the film-forming aid, defoamer, thickener and wetting agent in sequence, disperse for 10-30 minutes, filter and discharge to obtain water-based ultra-thin wood flame-retardant coating.

[0078] The preparation method of the above-mentioned MIL-101(Fe) synergist is as follows: FeCl3·6H2O (a metallic iron salt), terephthalic acid (H2BDC) (an organic ligand), and phytic acid are added to a microwave reactor containing dimethylformamide (DMF) solvent, wherein the molar ratio of FeCl3·6H2O, H2BDC, phytic acid, and DMF is 4:2:1:320. The mixture is then magnetically stirred for 20 min, microwaved at 110℃ for 1 h, and cooled to room temperature. The reaction products are then centrifuged, washed with ethanol, and vacuum dried sequentially to obtain the MIL-101(Fe) material. Subsequently, the MIL-101(Fe) material and silane coupling agent KH550 are added to a 90% ethanol aqueous solution, wherein the mass ratio of MIL-101(Fe), KH550, and the ethanol aqueous solution is 1:2:30. The mixture is microwaved at 50℃ for 30 min, then centrifuged and dried to obtain the MIL-101(Fe) synergist.

[0079] Example 5

[0080] This embodiment provides a water-based ultra-thin flame-retardant coating for wood. The difference between this embodiment and Embodiment 4 is that 3-mercaptopropyltriethoxysilane is used instead of KH550 in Embodiment 4, while the other conditions are the same.

[0081] The composition by weight is as follows: 65 parts of water-based acrylic emulsion, 22 parts of TZ-600C flame retardant, 4 parts of AP435 flame retardant, 3 parts of MIL-101(Fe) synergist, 5 parts of expanded perlite, 2 parts of propylene glycol butyl ether film-forming aid, 0.3 parts of TEGO-815 defoamer, 0.2 parts of TT-935 thickener, 0.2 parts of TEGO-500 wetting agent, and 3.3 parts of deionized water;

[0082] This embodiment also provides a method for preparing a water-based ultra-thin flame-retardant coating for wood:

[0083] S1. The synergist, expanded perlite and deionized water were mixed and dispersed at 30 Hz and 150 W for 8 min to obtain a mixture;

[0084] S2. Slowly add the mixture to the water-based acrylic emulsion, then add the film-forming aid, defoamer, thickener and wetting agent in sequence, disperse for 10-30 minutes, filter and discharge to obtain water-based ultra-thin wood flame-retardant coating.

[0085] The preparation method of the above-mentioned MIL-101(Fe) synergist is as follows: FeCl3·6H2O (a metallic iron salt), terephthalic acid (H2BDC) (an organic ligand), and phytic acid are added to a microwave reactor containing dimethylformamide (DMF) solvent, wherein the molar ratio of FeCl3·6H2O, H2BDC, phytic acid, and DMF is 4:2:1:320. The mixture is then magnetically stirred for 20 min, microwaved at 110℃ for 1 h, and cooled to room temperature. The reaction products are then centrifuged, washed with ethanol, and vacuum dried sequentially to obtain the MIL-101(Fe) material. Subsequently, the MIL-101(Fe) material and 3-mercaptopropyltriethoxysilane are added to a 90% aqueous ethanol solution, wherein the mass ratio of MIL-101(Fe), 3-mercaptopropyltriethoxysilane, and the aqueous ethanol solution is 1:2:30. The mixture is microwaved at 50℃ for 30 min, then centrifuged and dried to obtain the MIL-101(Fe) synergist.

[0086] Comparative Example 1

[0087] This comparative example provides a water-based ultra-thin flame-retardant coating for wood and its preparation method, specifically:

[0088] A water-based ultra-thin flame-retardant coating for wood comprises the following components by weight: 65 parts water-based acrylic emulsion, 5 parts FR-125 flame retardant, 20 parts FT-6501 flame retardant, 3 parts propylene glycol butyl ether film-forming aid, 0.1 parts TEGO-815 defoamer, 0.3 parts TT-935 thickener, 0.2 parts TEGO-500 wetting agent, and 6.4 parts deionized water.

[0089] This comparative example also provides a method for preparing a water-based ultra-thin flame-retardant coating for wood:

[0090] Flame retardant is added to water-based acrylic emulsion, followed by film-forming aid, defoamer, thickener and wetting agent in sequence. The mixture is dispersed for 10-30 minutes, filtered, and discharged to obtain water-based ultra-thin wood flame retardant coating.

[0091] Comparative Example 2

[0092] A water-based ultra-thin flame-retardant coating for wood comprises the following components by weight: 70 parts water-based acrylic emulsion, 22 parts FT-6500F flame retardant, 3 parts propylene glycol butyl ether film-forming aid, 0.1 parts TEGO-815 defoamer, 0.3 parts TT-935 thickener, 0.2 parts TEGO-500 wetting agent, and 4.4 parts deionized water.

[0093] Comparative Example 3

[0094] A water-based ultra-thin flame-retardant coating for wood comprises the following components by weight: 65 parts water-based acrylic emulsion, 22 parts TZ-600C flame retardant, 4 parts AP435 flame retardant, 2 parts propylene glycol butyl ether film-forming aid, 0.3 parts TEGO-815 defoamer, 0.2 parts TT-935 thickener, 0.2 parts TEGO-500 wetting agent, and 6.3 parts deionized water.

[0095] Comparative Example 4

[0096] A water-based ultra-thin flame-retardant coating for wood is described. The difference between this comparative example and Example 4 is that no silane coupling agent was added, while the other conditions are the same.

[0097] This comparative example provides a water-based ultra-thin flame-retardant coating for wood:

[0098] The composition by weight is as follows: 65 parts of water-based acrylic emulsion, 22 parts of TZ-600C flame retardant, 4 parts of AP435 flame retardant, 3 parts of MIL-101(Fe) synergist, 5 parts of expanded perlite, 2 parts of propylene glycol butyl ether film-forming aid, 0.3 parts of TEGO-815 defoamer, 0.2 parts of TT-935 thickener, 0.2 parts of TEGO-500 wetting agent, and 3.3 parts of deionized water;

[0099] This comparative example also provides a method for preparing a water-based ultra-thin flame-retardant coating for wood:

[0100] S1. The synergist, expanded perlite and deionized water were mixed and dispersed at 30 Hz and 150 W for 8 min to obtain a mixture;

[0101] S2. Slowly add the mixture to the water-based acrylic emulsion, then add the film-forming aid, defoamer, thickener and wetting agent in sequence, disperse for 10-30 minutes, filter and discharge to obtain water-based ultra-thin wood flame-retardant coating.

[0102] The preparation method of the above-mentioned MIL-101(Fe) synergist is as follows: FeCl3·6H2O, terephthalic acid (H2BDC) organic ligand, and phytic acid are added to a microwave reactor containing dimethylformamide (DMF) solvent, wherein the molar ratio of FeCl3·6H2O, H2BDC, phytic acid and DMF is 4:2:1:320. Then, the mixture is magnetically stirred for 20 min, microwaved at 110℃ for 1 h, and then cooled to room temperature. The reaction products are then centrifuged, washed with ethanol, and vacuum dried in sequence to obtain the unmodified MIL-101(Fe) synergist.

[0103] Comparative Example 5

[0104] A water-based ultra-thin flame-retardant coating for wood is described. The difference between this comparative example and Example 1 is that the microwave heating method in Example 1 is replaced by the traditional oven heating method, while the other conditions are the same.

[0105] This comparative example provides a water-based ultra-thin flame-retardant coating for wood:

[0106] The product comprises the following components by weight: 65 parts of aqueous acrylic emulsion, 5 parts of FR-125 flame retardant, 20 parts of FT-6501 flame retardant, 5 parts of MIL-101(Fe) synergist, 3 parts of propylene glycol butyl ether film-forming aid, 0.1 parts of TEGO-815 defoamer, 0.3 parts of TT-935 thickener, 0.2 parts of TEGO-500 wetting agent, and 1.4 parts of deionized water;

[0107] This embodiment also provides a method for preparing a water-based ultra-thin flame-retardant coating for wood:

[0108] Synergist and flame retardant are added sequentially to water-based acrylic emulsion, followed by film-forming aid, defoamer, thickener and wetting agent. The mixture is dispersed for 10-30 minutes, filtered, and discharged to obtain water-based ultra-thin wood flame retardant coating.

[0109] The preparation method of the above-mentioned MIL-101(Fe) synergist is as follows: FeCl3·6H2O (a metallic iron salt), terephthalic acid (H2BDC) (an organic ligand), and phytic acid are added to a microwave reactor containing dimethylformamide (DMF) solvent, wherein the molar ratio of FeCl3·6H2O, H2BDC, phytic acid, and DMF is 4:2:1:320. The mixture is then magnetically stirred for 20 min, reacted in an oven at 110℃ for 20 h, and cooled to room temperature. The reaction products are then centrifuged, washed with ethanol, and vacuum dried to obtain the MIL-101(Fe) material. Subsequently, the MIL-101(Fe) material and silane coupling agent KH550 are added to a 90% ethanol aqueous solution, wherein the mass ratio of MIL-101(Fe), KH550, and the ethanol aqueous solution is 1:2:30. The mixture is reacted in a microwave at 50℃ for 30 min, followed by centrifugation and drying to obtain the MIL-101(Fe) synergist.

[0110] Experimental Example 1

[0111] In this test, the basic properties of the water-based ultra-thin wood flame-retardant coatings obtained in the examples and comparative examples were tested according to GB / T 12441-2018 "Decorative Fire-retardant Coatings". Water resistance, impact resistance, adhesion and flexibility were tested according to GB / T 1733-1993, GB / T1732-2020, GB / T1720-2020 and GB / T1731-2020, respectively. The data results are shown in Table 1.

[0112] Table 1: Basic Performance Test Results of Waterborne Flame-Retardant Wood Coatings in Examples and Comparative Examples

[0113]

[0114]

[0115]

[0116] As shown in Table 1, all performance indicators of the water-based ultra-thin wood flame-retardant coatings obtained in Examples 1-5 are within the range required by national standards. Experimental results indicate that the water-based ultra-thin wood flame-retardant coatings obtained in this invention meet the product's flame-retardant qualification test and belong to the category of high-performance water-based flame-retardant coatings. Comparison with control examples shows that adding Fe-MOFs synergists can significantly improve its flame-retardant performance. The flame-retardant time of Example 3 can reach 36 minutes, indicating that this coating has excellent flame-retardant properties and can delay the combustion of the substrate during heating, fully demonstrating its significant role in blocking heat transfer and delaying flame combustion. In Example 4, MIL-101(Fe) possesses strong adsorption capacity and a high specific surface area. When MIL-101(Fe) covers the surface of expanded perlite, during heating, the MIL-101(Fe) coating on the expanded perlite surface releases adsorbed moisture or other volatile gases, providing more expansion force for the expanded perlite and promoting faster expansion of the expanded perlite at relatively low temperatures. The coating made from this material rapidly forms a barrier layer under high-temperature conditions, effectively suppressing fire and achieving the design of an ultra-thin coating. The granular structure of expanded perlite and the reinforcing effect of MIL-101(Fe) enable the coating to have better structural stability, increase the mechanical strength and toughness of the coating, effectively reduce cracking and peeling of the coating when subjected to external impact, and improve its impact resistance.

[0117] Experimental Example 2

[0118] The water-based flame-retardant coatings obtained in the examples and comparative examples were applied to the surface of a 200mm x 300mm x 5mm wooden board (sample). The samples were pre-sanded to ensure a smooth and flat surface, and the sides were sealed. After coating, the samples were dried at room temperature under natural conditions to constant weight (mass change not exceeding 0.5% within 24 hours), with a dry film thickness of approximately 0.2mm, and then tested. By controlling the valve of the butane spray gun, the total visible flame length was set to 6cm, and the flame root was 5cm away from the sample. The samples were directly exposed to the butane spray gun flame for 10s for qualitative evaluation. The results are shown in Table 2.

[0119] Table 2: Basic Performance Test Results of Water-Based Flame-Retardant Wood Coatings in Examples

[0120]

[0121] The results showed that the blank wooden board burned rapidly upon contact with a butane flame, and the flame spread quickly. After 10 seconds, the flame on the wood surface did not self-extinguish after the butane spray gun was removed. In contrast, the wooden board coated with the water-based flame-retardant coating obtained in Example 3 did not ignite after 10 seconds of flame contact, and the surface char layer structure was intact, with an average thickness of 5.2 mm, far exceeding the initial coating thickness of 0.2 mm. After further contact with the butane flame for 10 seconds, the average thickness of the surface char layer reached 10.5 mm. Example 4 successfully constructed an expanded and dense flame-retardant char layer through the synergistic effect of expanded perlite and Fe-MOFs, while ensuring that the expanded perlite expanded at a relatively low temperature. This innovative structure effectively blocks the heat and oxygen transfer path, thus achieving both flame retardancy and heat insulation. The wooden board did not ignite after 10 seconds of flame contact, and the surface char layer structure was intact, with an average thickness of 8.2 mm, far exceeding the initial coating thickness of 0.2 mm. After further contact with the butane flame for 10 seconds, the average thickness of the surface char layer reached 13.6 mm. In Example 5, the expanded perlite could not expand sufficiently at high temperatures, and its fire resistance was not as good as that in Example 4.

[0122] The above results all indicate that this water-based ultra-thin wood flame-retardant coating has good adhesion, impact resistance, flexibility, water resistance, temperature resistance and excellent fire-retardant properties.

[0123] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A water-based ultra-thin flame-retardant coating for wood, characterized in that, The raw materials for preparation are as follows (parts by weight): 65 parts of water-based acrylic emulsion, 22 parts of TZ-600C flame retardant, 4 parts of AP435 flame retardant, 3 parts of MIL-101(Fe) synergist, 5 parts of expanded perlite, 2 parts of propylene glycol butyl ether film-forming aid, 0.3 parts of TEGO-815N defoamer, 0.2 parts of TT-935 thickener, 0.2 parts of TEGO-500 wetting agent, and 3.3 parts of deionized water; The preparation method of the MIL-101(Fe) synergist is as follows: The metallic iron salt FeCl3·6H2O, the organic ligands terephthalic acid and phytic acid were added to a microwave reactor containing the solvent dimethylformamide, wherein the molar ratio of FeCl3·6H2O, terephthalic acid, phytic acid and dimethylformamide was 4:2:1:

320. The mixture was then magnetically stirred for 20 min, microwaved at 110℃ for 1 h, and cooled to room temperature. The reaction products were then centrifuged, washed with ethanol and vacuum dried in sequence to obtain the MIL-101(Fe) material. Subsequently, MIL-101(Fe) material and silane coupling agent KH550 were added to a 90% ethanol aqueous solution, wherein the mass ratio of MIL-101(Fe), KH550 and ethanol aqueous solution was 1:2:

30. After microwave reaction at 50°C for 30 min, the mixture was centrifuged and dried to obtain MIL-101(Fe) synergist. The MIL-101(Fe) synergist is coated on the surface of the expanded perlite.

2. The application of the water-based ultra-thin flame-retardant wood coating as described in claim 1 in the field of decoration.

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