Self-catalytic active fire extinguishing microcapsule, preparation method and application thereof
By using a core-shell structured microcapsule with a potassium salt catalyst as the core material of polyurethane microspheres and a melamine polymer shell, the environmental risks and high costs of perfluorohexanone core materials have been solved, achieving a highly efficient and low-cost active fire extinguishing effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI HEHUI JINYUAN TECH CO LTD
- Filing Date
- 2026-05-28
- Publication Date
- 2026-07-14
AI Technical Summary
Existing active fire extinguishing microcapsules using perfluorohexanone as the core material have problems such as high environmental risk, high cost and difficulty in large-scale application. Traditional flame retardants are difficult to achieve active suppression in fire and may degrade material performance.
Using polyurethane microspheres containing potassium salt catalysts as the core material, a core-shell structure of self-catalytic active fire extinguishing microcapsules is formed by the reaction of melamine and isocyanate to generate a polymer shell. The potassium salt catalyst decomposes at high temperatures to produce non-flammable gases such as carbon dioxide and nitrogen, which synergistically extinguish the fire.
It achieves active fire extinguishing at high temperatures, avoids the generation of toxic fluorine-containing gases, reduces raw material costs, is easy to scale up production, and enhances fire extinguishing efficiency.
Smart Images
Figure CN122377074A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of materials, and in particular relates to a self-catalytic active fire extinguishing microcapsule, its preparation method, and its application. Background Technology
[0002] Polymer materials, due to their lightweight, ease of processing, and excellent comprehensive mechanical properties, have been widely used in automobiles, construction, electronics, transportation, and other fields. However, most polymer materials are inherently flammable, exhibiting high heat release rates and rapid flame spread in fire scenarios, posing a serious threat to people's lives and property. Therefore, improving the fire safety of polymer materials has always been an important research direction in the field of materials science.
[0003] Currently, the main approach to improving the flame retardant properties of polymer materials is to introduce flame retardants containing elements such as halogens, phosphorus, nitrogen, boron, and silicon. These flame retardants exert their flame-retardant effect in the condensed or gas phase through mechanisms such as capturing free radicals, promoting char formation, and releasing non-combustible gases. However, these traditional flame retardants are mostly passive protections, primarily slowing down the combustion process after a fire has started, and are difficult to actively suppress. To achieve a high flame retardant rating, a high dosage is often required, but excessive addition of flame retardants inevitably degrades the mechanical properties of the matrix material. In addition, some phosphorus- or halogen-containing flame retardants release toxic small molecules when decomposed at high temperatures, exacerbating the smoke toxicity problem in fires.
[0004] In recent years, active fire extinguishing microcapsules have attracted widespread attention as a novel fire extinguishing material. These microcapsules typically have a core-shell structure, with the fire extinguishing core material encapsulated within a polymer shell. They remain stable under normal conditions, but when heated above the shell's tolerance threshold, the shell ruptures, releasing the core fire extinguishing agent. This allows for an active response in the early stages of a fire, enabling early detection and suppression. Currently, most reported active fire extinguishing microcapsules use perfluorohexanone (such as perfluoro(2-methyl-3-pentanone)) as the core material. Utilizing its low boiling point and high latent heat of vaporization, it rapidly vaporizes at high temperatures, absorbing heat and isolating oxygen to achieve a fire extinguishing effect. For example, CN119258475A discloses an active fire extinguishing microcapsule with perfluoro(2-methyl-3-pentanone) as the core material and gelatin as the wall material; CN120815314A discloses an active fire extinguishing microcapsule with perfluorohexanone as the core material and a fluoroacrylate copolymer as the shell.
[0005] However, the aforementioned active fire extinguishing microcapsules using perfluorohexanone compounds as core materials have the following drawbacks: First, perfluorohexanone may hydrolyze or pyrolyze under high-temperature flame conditions, producing fluorine-containing gases and acidic byproducts, posing potential environmental and health risks when used in confined spaces. Second, perfluorohexanone raw materials are expensive, and the microencapsulation process requires high precision in materials and equipment, resulting in high product manufacturing costs. Currently, it is mostly used in specific fields such as high-end new energy vehicles or energy storage systems, making it difficult to achieve large-scale application in ordinary polymer materials. Therefore, developing a novel microcapsule material that is cost-effective, environmentally friendly, and can effectively achieve active fire extinguishing functions has significant practical value. Summary of the Invention
[0006] The purpose of this invention is to provide a self-catalytic active fire extinguishing microcapsule, its preparation method, and its application. The specific technical solution to achieve the above-mentioned objectives is as follows: In a first aspect, the present invention provides a self-catalytic active fire extinguishing microcapsule, wherein the active fire extinguishing microcapsule has a core-shell structure, comprising a core material and a shell material covering the surface of the core material; the core material is a polyurethane microsphere containing a potassium salt catalyst, and the shell material is a polymer generated by the reaction of melamine and isocyanate. Further, the mass ratio of the core material to the shell material is 0.7:1-1.5:1.
[0007] Furthermore, the potassium salt catalyst is selected from at least one of potassium oxalate, potassium succinate, potassium tartrate, potassium malate, potassium formate, and potassium citrate.
[0008] Furthermore, the isocyanate is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.
[0009] Secondly, the present invention provides a method for preparing the aforementioned self-catalytic active fire extinguishing microcapsules, comprising the following steps: Preparation of S1 core material: (1) Dissolve isocyanate in n-hexane and stir evenly with ultrasonic assistance to obtain the first dispersion system; (2) The potassium salt catalyst and the polyhydroxy monomer were mixed in an organic solvent to obtain a second dispersion system; (3) The second dispersion system is added dropwise to the first dispersion system, and the temperature is raised to react, and polyurethane microspheres are generated by precipitation polymerization; (4) After the reaction is completed, the polyurethane microsphere core material containing potassium salt catalyst is obtained by centrifugation, washing and vacuum drying. Preparation of S2 shell: (5) Dissolve melamine and catalyst in an ionic liquid to obtain a homogeneous solution; (6) Add the polyurethane microsphere core material obtained in step S1 to the homogeneous solution obtained in step (5), disperse it evenly to obtain a mixed solution, and add isocyanate to the above mixed solution. (7) Stirring reaction, the polymer is generated and coated on the surface of polyurethane microspheres. After the reaction is completed, filter, wash and dry to obtain core-shell structured active fire extinguishing microcapsules.
[0010] Further, in step S1(3), the molar ratio of isocyanate to polyhydroxy monomer is 1.9:1 to 2.0:1, and the mass of potassium salt catalyst is 1% to 15% of the total monomer, wherein the total monomer refers to the sum of the mass of isocyanate and polyhydroxy monomer.
[0011] Further, in step S1(3), after the addition is completed, the temperature is raised to 50-100℃ and the reaction is stirred for 1-2 hours; in step S1(4), the separation is centrifugation at 10000-20000 rpm for 5-10 minutes, and the drying is vacuum drying at 80℃ for 3-6 hours.
[0012] Further, in step S2(5), the catalyst is stannous octoate, the mass of which is 0.4% of the mass of melamine, and the ionic liquid is 1-butyl-3-methylimidazolium acetate; in step S2(6), the molar ratio of the added isocyanate to melamine is 0.5:1 to 1.5:1, and the reaction time is 2 hours.
[0013] Furthermore, in step S2(7), the washing is acetone washing and the drying is vacuum drying.
[0014] Thirdly, the present invention provides the application of the self-catalytic active fire extinguishing microcapsules or the self-catalytic active fire extinguishing microcapsules prepared by the preparation method in the preparation of flame-retardant polymer materials.
[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention uses polyurethane microspheres containing a potassium salt catalyst as the core material. Under high-temperature heating conditions, the potassium salt catalyzes the decomposition of polyurethane to produce carbon dioxide, which releases non-flammable gas and dilutes the oxygen concentration to suppress flame spread, thus achieving active fire extinguishing. Compared to the fluorinated fire extinguishing core materials such as perfluorohexanone commonly used in existing technologies, this invention avoids the use of fluorinated compounds from the material system perspective, eliminating the risk of generating toxic fluorinated gases and acidic byproducts at high temperatures.
[0016] 2. The polyurethane and potassium salt catalysts used in this invention are both bulk industrial raw materials, with low raw material costs, simple synthesis processes, and easy to achieve large-scale production and application.
[0017] 3. This invention uses a polymer formed by the in-situ polymerization of melamine and isocyanate on the surface of the core material as the shell material. This polymer shell structure exhibits excellent thermal stability and char-forming properties. Before the shell breaks at a preset temperature to release the fire-extinguishing core material, it itself can act as a certain flame-retardant barrier. Simultaneously, the nitrogen-containing structure in the shell can release non-combustible gases such as nitrogen at high temperatures, creating a synergistic fire-extinguishing effect with the carbon dioxide produced by the decomposition of the core material, further enhancing the fire-extinguishing efficiency. Attached Figure Description
[0018] Figure 1 SEM image of the active fire extinguishing microcapsule with a core-shell structure prepared in Example 1. Detailed Implementation
[0019] The technical solutions of this disclosure will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of this disclosure, but not all embodiments, and are only used to illustrate this disclosure, and should not be regarded as limiting the scope of this disclosure. Based on the embodiments in this disclosure, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this disclosure.
[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
[0021] Unless otherwise specified, all raw materials used in the following examples and comparative examples are commercially available industrial-grade or chemically pure products. Unless otherwise specified, "parts" in the examples refer to parts by weight.
[0022] Any numerical range described in this invention includes endpoint values and any values between endpoint values, as well as any subranges formed by these endpoint values or any values within them.
[0023] The present invention will be described in detail below with reference to specific embodiments.
[0024] Example 1 (1) Preparation of core material: At room temperature, 17.4 g (0.1 mol) of toluene diisocyanate (TDI) was placed in a 250 mL three-necked flask, and 200 mL of n-hexane was added. The mixture was mechanically stirred at 300 rpm with ultrasonic assistance at 50 kHz and 200 W to obtain a uniformly mixed first dispersion system.
[0025] (2) Weigh 2.4 g of potassium malate and add it to a solution formed by dissolving 6.7 g (0.05 mol) of trimethylolpropane (TMP) in 200 mL of dichloromethane under stirring to obtain a second dispersion system.
[0026] (3) The second dispersion system is slowly added dropwise to the first dispersion system, the temperature is raised to 60°C, and the reaction is continued for 2 hours. The system gradually becomes turbid, and the polyurethane microspheres are precipitated through precipitation polymerization.
[0027] (4) After the reaction is complete, centrifuge at 10,000 rpm for 5 minutes, collect the precipitate, wash it three times with acetone, and vacuum dry it at 80°C for 5 hours to obtain polyurethane microsphere core material containing potassium salt catalyst.
[0028] (5) Preparation of the shell: 12.6 g (0.1 mol) of melamine and 0.05 g (equivalent to 0.4% of the mass of melamine) of stannous octoate catalyst were dissolved in 300 g of ionic liquid solvent [BMIM][OAc] under stirring at 300 rpm and 60 °C to obtain a homogeneous solution.
[0029] (6) Add 25.36 g of polyurethane microsphere core material obtained in step (4) to the homogeneous solution, disperse it evenly by ultrasonication to obtain a mixed solution, and slowly add 19.1 g (0.11 mol) of toluene diisocyanate (TDI) to the above mixed solution.
[0030] (7) Continue stirring the reaction for 2 hours to generate polymer coating on the surface of polyurethane microspheres. After the reaction is complete, filter, wash the product three times with acetone, and vacuum dry to obtain active fire extinguishing microcapsules with a core-shell structure.
[0031] The finished product prepared in Example 1 was tested using a scanning electron microscope (SEM), such as... Figure 1 As shown. From Figure 1 As can be seen, the active fire extinguishing microcapsules prepared by this invention exhibit a full, regular spherical shape, and the microspheres are well dispersed, with no obvious aggregation or adhesion. The surface of the microcapsules is dense, flat, and smooth, without obvious damage, holes, or depressions, indicating that the polymer shell has been successfully and uniformly coated on the surface of the potassium salt-containing polyurethane core material, forming a complete and closed core-shell structure.
[0032] Example 2 (1) Preparation of core material: At room temperature, 17.4 g (0.1 mol) of toluene diisocyanate (TDI) was placed in a 250 mL three-necked flask, and 200 mL of n-hexane was added. The mixture was mechanically stirred at 300 rpm with ultrasonic assistance at 50 kHz and 200 W to obtain a uniformly mixed first dispersion system.
[0033] (2) Weigh 3.6 g of potassium malate and add it to a solution formed by dissolving 6.7 g (0.05 mol) of trimethylolpropane (TMP) in 200 mL of dichloromethane under stirring to obtain a second dispersion system.
[0034] (3) The second dispersion system is slowly added dropwise to the first dispersion system, the temperature is raised to 60°C, and the reaction is continued for 2 hours. The system gradually becomes turbid, and the polyurethane microspheres are precipitated through precipitation polymerization.
[0035] (4) After the reaction is complete, centrifuge at 10,000 rpm for 5 minutes, collect the precipitate, wash it three times with acetone, and vacuum dry it at 80°C for 5 hours to obtain polyurethane microsphere core material containing potassium salt catalyst.
[0036] (5) Preparation of the shell: 12.6 g (0.1 mol) of melamine and 0.05 g (equivalent to 0.4% of the mass of melamine) of stannous octoate catalyst were dissolved in 300 g of ionic liquid solvent [BMIM][OAc] under stirring at 300 rpm and 60 °C to obtain a homogeneous solution.
[0037] (6) Add 31.7 g of polyurethane microsphere core material obtained in step (4) to the homogeneous solution, disperse it evenly by ultrasonication to obtain a mixed solution, and slowly add 19.1 g (0.11 mol) of toluene diisocyanate (TDI) to the above mixed solution.
[0038] (7) Continue stirring the reaction for 2 hours to generate polymer coating on the surface of polyurethane microspheres. After the reaction is complete, filter, wash the product three times with acetone, and vacuum dry to obtain active fire extinguishing microcapsules with a core-shell structure.
[0039] Example 3 (1) Preparation of core material: At room temperature, 16.8 g (0.1 mol) of hexamethylene diisocyanate (HDI) was placed in a 250 mL three-necked flask, and 200 mL of n-hexane was added. The mixture was mechanically stirred at 300 rpm with ultrasonic assistance at 50 kHz and 200 W to obtain a uniformly mixed first dispersion system.
[0040] (2) Weigh 0.85 g of potassium formate and add it to a solution formed by dissolving 6.7 g (0.05 mol) of trimethylolpropane (TMP) in 200 mL of dichloromethane under stirring to obtain a second dispersion system.
[0041] (3) The second dispersion system is slowly added dropwise to the first dispersion system, the temperature is raised to 60°C, and the reaction is continued for 2 hours. The system gradually becomes turbid, and the polyurethane microspheres are precipitated through precipitation polymerization.
[0042] (4) After the reaction is complete, centrifuge at 10,000 rpm for 5 minutes, collect the precipitate, wash it three times with acetone, and vacuum dry it at 80°C for 5 hours to obtain polyurethane microsphere core material containing potassium salt catalyst.
[0043] (5) Preparation of the shell: 12.6 g (0.1 mol) of melamine and 0.05 g (equivalent to 0.4% of the mass of melamine) of stannous octoate catalyst were dissolved in 300 g of ionic liquid solvent [BMIM][OAc] under stirring at 300 rpm and 60 °C to obtain a homogeneous solution.
[0044] (6) Add 38.04 g of polyurethane microsphere core material obtained in step (4) to the homogeneous solution, disperse it evenly by ultrasonication to obtain a mixed solution, and slowly add 19.1 g (0.11 mol) of toluene diisocyanate (TDI) to the above mixed solution.
[0045] (7) Continue stirring the reaction for 2 hours to generate polymer coating on the surface of polyurethane microspheres. After the reaction is complete, filter, wash the product three times with acetone, and vacuum dry to obtain active fire extinguishing microcapsules with a core-shell structure.
[0046] Example 4 (1) Preparation of core material: At room temperature, 22.2 g (0.1 mol) of isophorone diisocyanate (IPDI) was placed in a 250 mL three-necked flask, and 200 mL of n-hexane was added. The mixture was mechanically stirred at 300 rpm with ultrasonic assistance at 50 kHz and 200 W to obtain a uniformly mixed first dispersion system.
[0047] (2) Weigh 1.45 g of potassium citrate and add it to a solution formed by dissolving 6.7 g (0.05 mol) of trimethylolpropane (TMP) in 200 mL of dichloromethane under stirring to obtain a second dispersion system.
[0048] (3) The second dispersion system is slowly added dropwise to the first dispersion system, the temperature is raised to 60°C, and the reaction is continued for 2 hours. The system gradually becomes turbid, and the polyurethane microspheres are precipitated through precipitation polymerization.
[0049] (4) After the reaction is complete, centrifuge at 10,000 rpm for 5 minutes, collect the precipitate, wash it three times with acetone, and vacuum dry it at 80°C for 5 hours to obtain polyurethane microsphere core material containing potassium salt catalyst.
[0050] (5) Preparation of the shell: 12.6 g (0.1 mol) of melamine and 0.05 g (equivalent to 0.4% of the mass of melamine) of stannous octoate catalyst were dissolved in 300 g of ionic liquid solvent [BMIM][OAc] under stirring at 300 rpm and 60 °C to obtain a homogeneous solution.
[0051] (6) Add 25.36 g of polyurethane microsphere core material obtained in step (4) to the homogeneous solution, disperse it evenly by ultrasonication to obtain a mixed solution, and slowly add 19.1 g (0.11 mol) of toluene diisocyanate (TDI) to the above mixed solution.
[0052] (7) Continue stirring the reaction for 2 hours to generate polymer coating on the surface of polyurethane microspheres. After the reaction is complete, filter, wash the product three times with acetone, and vacuum dry to obtain active fire extinguishing microcapsules with a core-shell structure.
[0053] Example 5 (1) Preparation of core material: At room temperature, 22.2 g (0.1 mol) of isophorone diisocyanate (IPDI) was placed in a 250 mL three-necked flask, and 200 mL of n-hexane was added. The mixture was mechanically stirred at 300 rpm with ultrasonic assistance at 50 kHz and 200 W to obtain a uniformly mixed first dispersion system.
[0054] (2) Weigh 1.5 g of potassium malate and add it to a solution formed by dissolving 6.7 g (0.05 mol) of trimethylolpropane (TMP) in 200 mL of dichloromethane under stirring to obtain a second dispersion system.
[0055] (3) The second dispersion system is slowly added dropwise to the first dispersion system, the temperature is raised to 60°C, and the reaction is continued for 2 hours. The system gradually becomes turbid, and the polyurethane microspheres are precipitated through precipitation polymerization.
[0056] (4) After the reaction is complete, centrifuge at 10,000 rpm for 5 minutes, collect the precipitate, wash it three times with acetone, and vacuum dry it at 80°C for 5 hours to obtain polyurethane microsphere core material containing potassium salt catalyst.
[0057] (5) Preparation of the shell: 12.6 g (0.1 mol) of melamine and 0.05 g (equivalent to 0.4% of the mass of melamine) of stannous octoate catalyst were dissolved in 300 g of ionic liquid solvent [BMIM][OAc] under stirring at 300 rpm and 60 °C to obtain a homogeneous solution.
[0058] (6) Add 28.53 g of polyurethane microsphere core material obtained in step (4) to the homogeneous solution, disperse it evenly by ultrasonication to obtain a mixed solution, and slowly add 19.1 g (0.11 mol) of toluene diisocyanate (TDI) to the above mixed solution.
[0059] (7) Continue stirring the reaction for 2 hours to generate polymer coating on the surface of polyurethane microspheres. After the reaction is complete, filter, wash the product three times with acetone, and vacuum dry to obtain active fire extinguishing microcapsules with a core-shell structure.
[0060] Comparative Example 1 (1) Preparation of core material: At room temperature, 17.4 g (0.1 mol) of toluene diisocyanate (TDI) was placed in a 250 mL three-necked flask, and 200 mL of n-hexane was added. The mixture was mechanically stirred at 300 rpm with ultrasonic assistance at 50 kHz and 200 W to obtain a uniformly mixed first dispersion system.
[0061] (2) Without adding any potassium salt, 6.7 g (0.05 mol) of trimethylolpropane (TMP) was dissolved in 200 mL of dichloromethane as a second dispersion system.
[0062] (3) The second dispersion system is slowly added dropwise to the first dispersion system, the temperature is raised to 60°C, and the reaction is continued for 2 hours. The system gradually becomes turbid, and the polyurethane microspheres are precipitated through precipitation polymerization.
[0063] (4) After the reaction is complete, centrifuge at 10,000 rpm for 5 minutes, collect the precipitate, wash it three times with acetone, and vacuum dry it at 80°C for 5 hours to obtain pure polyurethane microsphere core material without potassium salt.
[0064] (5) Preparation of the shell: 12.6 g (0.1 mol) of melamine and 0.05 g (equivalent to 0.4% of the mass of melamine) of stannous octoate catalyst were dissolved in 300 g of ionic liquid solvent [BMIM][OAc] under stirring at 300 rpm and 60 °C to obtain a homogeneous solution.
[0065] (6) Add 25.36 g of pure polyurethane microsphere core material obtained in step (4) to the homogeneous solution, disperse it evenly by ultrasonication to obtain a mixed solution, and slowly add 19.1 g (0.11 mol) of toluene diisocyanate (TDI) to the above mixed solution.
[0066] (7) Continue stirring the reaction for 2 hours to generate polymer coating on the surface of polyurethane microspheres. After the reaction is complete, filter the product, wash it three times with acetone, and dry it under vacuum to obtain core-shell structured microcapsules.
[0067] Comparative Example 2 (1) Preparation of core material: At room temperature, 17.4 g (0.1 mol) of toluene diisocyanate (TDI) was placed in a 250 mL three-necked flask, and 200 mL of n-hexane was added. The mixture was mechanically stirred at 300 rpm with ultrasonic assistance at 50 kHz and 200 W to obtain a uniformly mixed first dispersion system.
[0068] (2) Without adding any potassium salt, 6.7 g (0.05 mol) of trimethylolpropane (TMP) was dissolved in 200 mL of dichloromethane as a second dispersion system.
[0069] (3) The second dispersion system is slowly added dropwise to the first dispersion system, the temperature is raised to 60°C, and the reaction is continued for 2 hours. The system gradually becomes turbid, and the polyurethane microspheres are precipitated through precipitation polymerization.
[0070] (4) After the reaction is complete, centrifuge at 10,000 rpm for 5 minutes, collect the precipitate, wash it three times with acetone, and vacuum dry it at 80°C for 5 hours to obtain pure polyurethane microsphere core material without potassium salt.
[0071] (5) Preparation of the shell: 2.4 g potassium malate, 12.6 g (0.1 mol) melamine and 0.0126 g (equivalent to 0.1% of the mass of melamine) stannous octoate catalyst were dissolved in 300 g ionic liquid solvent [BMIM][OAc] under stirring at 300 rpm and 60 °C to obtain a homogeneous solution.
[0072] (6) Add 25.36 g of pure polyurethane microsphere core material obtained in step (4) to the homogeneous solution, disperse it evenly by ultrasonication to obtain a mixed solution, and slowly add 19.1 g (0.11 mol) of toluene diisocyanate (TDI) to the above mixed solution.
[0073] (7) Continue stirring the reaction for 2 hours to generate polymer coating on the surface of polyurethane microspheres. After the reaction is complete, filter the product, wash it three times with acetone, and dry it under vacuum to obtain core-shell structured microcapsules.
[0074] Comparative Example 3 (1) Preparation of core material: At room temperature, 17.4 g (0.1 mol) of toluene diisocyanate (TDI) was placed in a 250 mL three-necked flask, and 200 mL of n-hexane was added. The mixture was mechanically stirred at 300 rpm with the assistance of ultrasonic waves at 50 kHz and 200 W to obtain a uniformly mixed first dispersion system.
[0075] (2) Weigh 0.12 g of potassium malate and add it to a solution formed by dissolving 6.7 g (0.05 mol) of trimethylolpropane (TMP) in 200 mL of dichloromethane under stirring to obtain a second dispersion system.
[0076] (3) The second dispersion system is slowly added dropwise to the first dispersion system, the temperature is raised to 60°C, and the reaction is continued for 2 hours. The system gradually becomes turbid, and the polyurethane microspheres are precipitated through precipitation polymerization.
[0077] (4) After the reaction is complete, centrifuge at 10,000 rpm for 5 minutes, collect the precipitate, wash it three times with acetone, and vacuum dry it at 80°C for 5 hours to obtain polyurethane microsphere core material containing potassium salt catalyst.
[0078] (5) Preparation of the shell: 12.6 g (0.1 mol) of melamine and 0.05 g (equivalent to 0.4% of the mass of melamine) of stannous octoate catalyst were dissolved in 300 g of ionic liquid solvent [BMIM][OAc] under stirring at 300 rpm and 60 °C to obtain a homogeneous solution.
[0079] (6) Add 15.85 g of polyurethane microsphere core material obtained in step (4) to the homogeneous solution, disperse it evenly by ultrasonication to obtain a mixed solution, and slowly add 19.1 g (0.11 mol) of toluene diisocyanate (TDI) to the above mixed solution.
[0080] (7) Continue stirring the reaction for 2 hours to generate polymer coating on the surface of polyurethane microspheres. After the reaction is complete, filter, wash the product three times with acetone, and vacuum dry to obtain active fire extinguishing microcapsules with a core-shell structure.
[0081] Comparative Example 4 (1) Preparation of core material: At room temperature, 17.4 g (0.1 mol) of toluene diisocyanate (TDI) was placed in a 250 mL three-necked flask, and 200 mL of n-hexane was added. The mixture was mechanically stirred at 300 rpm with ultrasonic assistance at 50 kHz and 200 W to obtain a uniformly mixed first dispersion system.
[0082] (2) Weigh 4.82 g of potassium malate and add it to a solution formed by dissolving 6.7 g (0.05 mol) of trimethylolpropane (TMP) in 200 mL of dichloromethane under stirring to obtain a second dispersion system.
[0083] (3) The second dispersion system is slowly added dropwise to the first dispersion system, the temperature is raised to 60°C, and the reaction is continued for 2 hours. The system gradually becomes turbid, and the polyurethane microspheres are precipitated through precipitation polymerization.
[0084] (4) After the reaction is complete, centrifuge at 10,000 rpm for 5 minutes, collect the precipitate, wash it three times with acetone, and vacuum dry it at 80°C for 5 hours to obtain polyurethane microsphere core material containing potassium salt catalyst.
[0085] (5) Preparation of the shell: 12.6 g (0.1 mol) of melamine and 0.05 g (equivalent to 0.4% of the mass of melamine) of stannous octoate catalyst were dissolved in 300 g of ionic liquid solvent [BMIM][OAc] under stirring at 300 rpm and 60 °C to obtain a homogeneous solution.
[0086] (6) Add 25.36 g of polyurethane microsphere core material obtained in step (4) to the homogeneous solution, disperse it evenly by ultrasonication to obtain a mixed solution, and slowly add 19.1 g (0.11 mol) of toluene diisocyanate (TDI) to the above mixed solution.
[0087] (7) Continue stirring the reaction for 2 hours to generate polymer coating on the surface of polyurethane microspheres. After the reaction is complete, filter, wash the product three times with acetone, and vacuum dry to obtain active fire extinguishing microcapsules with a core-shell structure.
[0088] Comparative Example 5 (1) Preparation of core material: At room temperature, 16.8 g (0.1 mol) of hexamethylene diisocyanate (HDI) was placed in a 250 mL three-necked flask, and 200 mL of n-hexane was added. The mixture was mechanically stirred at 300 rpm with ultrasonic assistance at 50 kHz and 200 W to obtain a uniformly mixed first dispersion system.
[0089] (2) Weigh 0.85 g of potassium formate and add it to a solution formed by dissolving 6.7 g (0.05 mol) of trimethylolpropane (TMP) in 200 mL of dichloromethane under stirring to obtain a second dispersion system.
[0090] (3) The second dispersion system is slowly added dropwise to the first dispersion system, the temperature is raised to 60°C, and the reaction is continued for 2 hours. The system gradually becomes turbid, and the polyurethane microspheres are precipitated through precipitation polymerization.
[0091] (4) After the reaction is complete, centrifuge at 10,000 rpm for 5 minutes, collect the precipitate, wash it three times with acetone, and vacuum dry it at 80°C for 5 hours to obtain polyurethane microsphere core material containing potassium salt catalyst.
[0092] (5) Preparation of the shell: 12.6 g (0.1 mol) of melamine and 0.05 g (equivalent to 0.4% of the mass of melamine) of stannous octoate catalyst were dissolved in 300 g of ionic liquid solvent [BMIM][OAc] under stirring at 300 rpm and 60 °C to obtain a homogeneous solution.
[0093] (6) Add 6.34 g of polyurethane microsphere core material obtained in step (4) to the homogeneous solution, disperse it evenly by ultrasonication to obtain a mixed solution, and slowly add 19.1 g (0.11 mol) of toluene diisocyanate (TDI) to the above mixed solution.
[0094] (7) Continue stirring the reaction for 2 hours to generate polymer coating on the surface of polyurethane microspheres. After the reaction is complete, filter, wash the product three times with acetone, and vacuum dry to obtain active fire extinguishing microcapsules with a core-shell structure.
[0095] Comparative Example 6 (1) Preparation of core material: At room temperature, 17.4 g (0.1 mol) of toluene diisocyanate (TDI) was placed in a 250 mL three-necked flask, and 200 mL of n-hexane was added. The mixture was mechanically stirred at 300 rpm with ultrasonic assistance at 50 kHz and 200 W to obtain a uniformly mixed first dispersion system.
[0096] (2) Weigh 2.4 g of potassium malate and add it to a solution formed by dissolving 6.7 g (0.05 mol) of trimethylolpropane (TMP) in 200 mL of dichloromethane under stirring to obtain a second dispersion system.
[0097] (3) The second dispersion system is slowly added dropwise to the first dispersion system, the temperature is raised to 60°C, and the reaction is continued for 2 hours. The system gradually becomes turbid, and the polyurethane microspheres are precipitated through precipitation polymerization.
[0098] (4) After the reaction is complete, centrifuge at 10,000 rpm for 5 minutes, collect the precipitate, wash it three times with acetone, and vacuum dry it at 80°C for 5 hours to obtain polyurethane microsphere core material containing potassium salt catalyst.
[0099] (5) Preparation of the shell: 12.6 g (0.1 mol) of melamine and 0.05 g (equivalent to 0.4% of the mass of melamine) of stannous octoate catalyst were dissolved in 300 g of ionic liquid solvent [BMIM][OAc] under stirring at 300 rpm and 60 °C to obtain a homogeneous solution.
[0100] (6) Add 18.08 g of polyurethane microsphere core material obtained in step (4) to the homogeneous solution, disperse it evenly by ultrasonication to obtain a mixed solution, and slowly add 10.0 g (about 0.057 mol) of toluene diisocyanate (TDI) to the above mixed solution.
[0101] (7) Continue stirring the reaction for 2 hours to generate polymer coating on the surface of polyurethane microspheres. After the reaction is complete, filter, wash the product three times with acetone, and vacuum dry to obtain active fire extinguishing microcapsules with a core-shell structure.
[0102] The microcapsules prepared using the above embodiments and comparative examples were used to test their fire extinguishing performance. The test method was as follows: The microcapsules to be tested are mixed with a polyurethane substrate (such as thermoplastic polyurethane elastomer) at a mass ratio of 1:1, and the mixture is prepared into a fire extinguishing sheet with a size of 5 cm × 5 cm × 0.5 cm in a sheet mold by melt blending or solution casting.
[0103] The test was conducted in a 10 L sealed stainless steel chamber with a 2 cm diameter pressure relief hole in the center of the side. 50 mL of gasoline was placed in a metal combustion plate at the bottom of the chamber, ignited, and pre-ignited for 10 seconds until a stable flame was formed. Then, a fire extinguishing disc was quickly placed horizontally about 5 cm above the combustion plate, and the chamber door was immediately closed. A stopwatch was used to record the time from the placement of the extinguishing disc to the complete extinguishing of the flame inside the chamber. Each experiment was repeated three times, and the average value was taken as the final extinguishing time.
[0104] The performance test results are shown in Table 1.
[0105] Table 1
[0106] As shown in Table 1, the self-catalytic active fire extinguishing microcapsules prepared in this invention have a fire extinguishing time of only 20-29 seconds, significantly better than the comparative examples. Comparative Example 1 (without potassium salt) had a fire extinguishing time as long as 95 seconds, and Comparative Example 2 (potassium salt physically blended in the shell) had a fire extinguishing time of 64 seconds, both far inferior to the examples. This indicates that the potassium salt catalyst must be precisely encapsulated inside the polyurethane core material to effectively catalyze the decomposition to produce carbon dioxide and achieve active fire extinguishing. Comparative Example 3 (potassium salt content 0.5%) and Comparative Example 4 (potassium salt content 19%) had fire extinguishing times of 87 seconds and 37 seconds, respectively, both inferior to the examples, proving that the potassium salt content needs to be controlled within the range of 1%-15%. Comparative Example 5 (core-shell mass ratio 0.2:1) and Comparative Example 6 (core-shell mass ratio 0.57:1) had fire extinguishing times of 41 seconds and 45 seconds, respectively, both inferior to the examples, further proving that an excessively low core-shell mass ratio or an excessively thick shell layer will lead to a significant decrease in fire extinguishing efficiency.
[0107] This indicates that only by precisely encapsulating the potassium salt catalyst inside the polyurethane core material can the polyurethane be effectively catalyzed to decompose and produce carbon dioxide when heated, thereby achieving efficient active fire suppression.
[0108] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.
Claims
1. A self-catalytic active fire extinguishing microcapsule, characterized in that, The active fire extinguishing microcapsule has a core-shell structure, including a core material and a shell material covering the surface of the core material; the core material is a polyurethane microsphere containing a potassium salt catalyst, and the shell material is a polymer generated by the reaction of melamine and isocyanate.
2. The self-catalytic active fire extinguishing microcapsule according to claim 1, characterized in that, The mass ratio of the core material to the shell material is 0.7:1 to 1.5:
1.
3. The self-catalytic active fire extinguishing microcapsule according to claim 1, characterized in that, The potassium salt catalyst is selected from at least one of potassium oxalate, potassium succinate, potassium tartrate, potassium malate, potassium formate, and potassium citrate.
4. The self-catalytic active fire extinguishing microcapsule according to claim 1, characterized in that, The isocyanate is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.
5. A method for preparing the self-catalytic active fire extinguishing microcapsule as described in any one of claims 1-4, characterized in that, Includes the following steps: Preparation of S1 core material: (1) Dissolve isocyanate in n-hexane and stir evenly with ultrasonic assistance to obtain the first dispersion system; (2) The potassium salt catalyst and the polyhydroxy monomer were mixed in an organic solvent to obtain a second dispersion system; (3) The second dispersion system is added dropwise to the first dispersion system, and the temperature is raised to react, and polyurethane microspheres are generated by precipitation polymerization; (4) After the reaction is completed, the polyurethane microsphere core material containing potassium salt catalyst is obtained by centrifugation, washing and vacuum drying. Preparation of S2 shell: (5) Dissolve melamine and catalyst in an ionic liquid to obtain a homogeneous solution; (6) Add the polyurethane microsphere core material obtained in step S1 to the homogeneous solution obtained in step (5), disperse it evenly to obtain a mixed solution, and add isocyanate to the above mixed solution. (7) Stirring reaction, the polymer is generated and coated on the surface of polyurethane microspheres. After the reaction is completed, filter, wash and dry to obtain core-shell structured active fire extinguishing microcapsules.
6. The preparation method according to claim 5, characterized in that, In step S1(3), the molar ratio of isocyanate to polyhydroxy monomer is 1.9:1 to 2.0:1, and the mass of potassium salt catalyst is 1% to 15% of the total monomer mass, where the total monomer mass refers to the sum of the masses of isocyanate and polyhydroxy monomer.
7. The preparation method according to claim 5, characterized in that, In step S1(3), after the addition is completed, the temperature is raised to 50-100℃ and the reaction is stirred for 1-2 hours; in step S1(4), the separation is centrifugation at 10000-20000 rpm for 5-10 minutes, and the drying is vacuum drying at 80℃ for 3-6 hours.
8. The preparation method according to claim 5, characterized in that, In step S2(5), the catalyst is stannous octoate, the mass of which is 0.4% of the mass of melamine, and the ionic liquid is 1-butyl-3-methylimidazolium acetate; in step S2(6), the molar ratio of the added isocyanate to melamine is 0.5:1 to 1.5:1, and the reaction time is 2 hours.
9. The preparation method according to claim 5, characterized in that, In step S2(7), the washing is acetone washing and the drying is vacuum drying.
10. The application of the self-catalytic active fire extinguishing microcapsule according to any one of claims 1-4 or the self-catalytic active fire extinguishing microcapsule prepared by the preparation method according to any one of claims 5-9 in the preparation of flame-retardant polymer materials.