Halogen-free and non-toxic fire extinguishing agent for coal mines and its preparation method and application

Abstract

The invention discloses a halogen-free and non-toxic fire extinguishing agent for coal mines, a preparation method thereof and an application thereof, and relates to the field of fire extinguishing agents. The halogen-free and non-toxic fire extinguishing agent for coal mines comprises bio-based polyester, ultrafine magnesium silicate, antimony trioxide, modified silicate, polylactic acid, ammonium polyphosphate, nano titanium dioxide, fluorinated polymer, graphene oxide, polyurethane foam, magnesium aluminum hydrotalcite and polyvinyl pyrrolidone. The fire extinguishing agent combines bio-based polyester, modified silicate, polylactic acid, fluorinated polymer with antimony trioxide, magnesium aluminum hydrotalcite and the like to configure a high-efficiency fire extinguishing agent that has fire extinguishing performance and is halogen-free and environmentally friendly. The fire extinguishing agent can quickly form an isolation layer when used to effectively prevent flame propagation. The fire extinguishing agent still maintains stability under high temperature and high pressure environments and is suitable for various coal mine workplaces.

Description

Technical Field

[0001] The invention relates to the field of fire extinguishing agents, and in particular to a halogen-free and non-toxic fire extinguishing agent for coal mines, and a preparation method and application thereof. Background Art

[0002] As an important energy production base, the safety of coal mines has always been a focus of attention. Fire accidents not only have a serious impact on the production of coal mines, but also pose a threat to the lives of miners. Traditional fire extinguishing agents usually contain halogen compounds, such as bromides and chlorides. Although they can effectively suppress flames, they may release toxic gases during the fire extinguishing process, causing environmental pollution and personnel health risks. Therefore, it is particularly important to develop a halogen-free, non-toxic fire extinguishing agent.

[0003] With the increasing awareness of environmental protection, many countries and regions have begun to restrict the use of halogen compounds and advocate the use of more environmentally friendly alternatives. In addition, the particularity of the coal mine working environment requires that the fire extinguishing agent not only has good fire extinguishing performance, but also can work effectively under extreme conditions such as high temperature and low oxygen. Therefore, the development of a coal mine fire extinguishing agent with excellent performance and environmental friendliness will not only help improve the safety level of coal mine production, but also help protect the health of miners.

[0004] At present, most of the fire extinguishing agents on the market are compounds containing halogens or other harmful ingredients. After use, these fire extinguishing agents may cause long-term pollution to soil and water sources, affecting the ecological environment and human health. Therefore, a new type of halogen-free and non-toxic coal mine fire extinguishing agent is urgently needed to meet the dual needs of safety and environmental protection. Summary of the invention

[0005] In view of this, the present invention aims to provide a halogen-free and non-toxic fire extinguishing agent for coal mines, and a preparation method and application thereof. The fire extinguishing agent combines bio-based polyester, modified silicate, polylactic acid, fluorinated polymer with antimony trioxide, magnesium aluminum hydrotalcite, etc. to prepare a high-efficiency fire extinguishing agent that has fire extinguishing performance and is halogen-free and environmentally friendly. The fire extinguishing agent can quickly form an isolation layer when used to effectively prevent the spread of flames. The fire extinguishing agent remains stable under high temperature and high pressure environments and is suitable for various coal mine workplaces.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a halogen-free and non-toxic fire extinguishing agent for coal mines, the halogen-free and non-toxic fire extinguishing agent for coal mines comprises the following raw materials in parts by weight:

[0008] 9-21 parts of bio-based polyester; 20-30 parts of ultrafine magnesium silicate; 20-30 parts of antimony trioxide; 35-45 parts of modified silicate; 8-14 parts of polylactic acid; 35-45 parts of ammonium polyphosphate; 3-10 parts of nano titanium dioxide; 2-8 parts of fluorinated polymer; 3-10 parts of graphene oxide; 20-30 parts of polyurethane foam; 25-35 parts of magnesium aluminum hydrotalcite and 3-10 parts of polyvinyl pyrrolidone.

[0009] As a further embodiment of the present invention, the bio-based polyester is a polylactic acid-ethylene (PLA-EVA) copolymer having a glass transition temperature of 55-65°C, and a carbonized layer is formed at a high temperature greater than the glass transition temperature to block the transfer of flames and heat.

[0010] As a further scheme of the present invention, the polylactic acid-ethylene (PLA-EVA) copolymer is converted from biomass raw materials into lactic acid through microbial fermentation, the lactic acid generates oligolactic acid (PLA) through a condensation reaction, and high molecular weight polylactic acid is generated through a ring-opening polymerization reaction under the action of a tin catalyst; PLA and ethylene-vinyl acetate comonomer (EVA) are copolymerized at 180-200° C. and 1-5 MPa pressure, the copolymerization reaction is catalyzed by benzoyl peroxide, unreacted monomers and oligomers are removed, and the copolymer is dried to a water content of less than 0.1%, and the dried copolymer is crushed into powder or granules to obtain the product.

[0011] As a further solution of the present invention, the biomass raw material is corn starch or sugar cane, and the polylactic acid-ethylene (PLA-EVA) copolymer is copolymerized by PLA and EVA. The melting point of the PLA-EVA copolymer is in the range of 160-180°C, and it can be degraded in the natural environment to reduce pollution to the environment. It forms a carbonized layer at high temperature to effectively isolate flames and heat. Its moderate melting point and glass transition temperature are suitable for the use environment of coal mine fire extinguishing agents.

[0012] As a further solution of the present invention, the ultrafine magnesium silicate is an ultrafine magnesium silicate powder with a particle size of 15-50nm and a specific surface area of ​​130m² / g; the antimony trioxide has a particle size of 100nm to 1um and a specific surface area of ​​20m² / g.

[0013] As a further embodiment of the present invention, the modified silicate is a modified silicate powder having an average particle size of less than 1 micron and a specific surface area of ​​greater than 100 m² / g.

[0014] As a further embodiment of the present invention, the preparation method of the modified silicate is:

[0015] Using natural silicate minerals as silicate raw materials, using a ball mill to crush the natural silicate minerals to a particle size of 10-100 microns, and sieving to obtain silicate powder with uniform particle size;

[0016] Dissolving organosilane as a modifier in an organic solvent to prepare a modifier solution, wherein the organic solvent is ethanol and the prepared modifier solution has a concentration of 1%-10%;

[0017] The pretreated silicate powder is placed in a modifier solution, the solid-liquid ratio is controlled to be 1:5 to 1:10, and a coupling agent is added, and stirred at room temperature for 1-2 hours to allow the silicate surface to fully contact the modifier, and ultrasonic dispersion treatment is performed for 30-60 minutes;

[0018] The impregnated silicate powder is subjected to a reaction treatment at 80-120° C. for 2-4 hours using a stirred reactor. Through heating and stirring, the modifier reacts with the surface of the silicate powder to form a stable modified layer;

[0019] After the reaction is completed, the modified silicate powder is separated from the solid by a vacuum filter and washed 2-3 times with deionized water to remove the unreacted modifier and other impurities;

[0020] The washed modified silicate powder is dried in a drying device at a drying temperature of 100-120° C. for 4-6 hours, and then pulverized using a jet mill to obtain a modified silicate powder with a particle size of less than 1 micron.

[0021] As a further solution of the present invention, the silicate raw material is one or more of bentonite, kaolin, and mica; the organosilane is KH-550 or KH-560; and the coupling agent is γ-aminopropyltriethoxysilane.

[0022] As a further scheme of the present invention, the polylactic acid powder is prepared by ring-opening polymerization of lactic acid monomer in the presence of a tin catalyst at a temperature of 130-180°C for 10-30 hours, and has high heat resistance. When added simultaneously with the bio-based polyester, it not only ensures high heat resistance (provided by PLA), but also provides better thermal decomposition properties (provided by PLA-EVA), which helps to improve the fire extinguishing effect.

[0023] As a further embodiment of the present invention, the fluorinated polymer is fluorinated polyethylene, which is prepared from vinyl fluoride monomer (VDF) by the following preparation method:

[0024] Add dimethylformamide as a solvent into a reaction kettle, add a surfactant and a buffer into the solvent, and stir evenly, wherein the surfactant is hexadecyltrimethylammonium bromide (CTAB) and the buffer is a phosphate buffer;

[0025] Dissolve potassium persulfate (KPS) in deionized water to prepare an initiator solution;

[0026] Adding ethylene fluoride monomer into the reactor and gradually increasing the pressure to a reaction pressure of 5-10 MPa, and after the pressure of the ethylene fluoride monomer reaches a predetermined value, adding an initiator solution into the reactor;

[0027] The temperature of the reactor was controlled at 50-90°C and stirred evenly. The reaction was continued for 4-12 hours. After the reaction was completed, the pressure was slowly reduced to normal pressure to stop the reaction.

[0028] The reaction product is filtered through a filter cloth, the fluorinated polyethylene solid is collected, and the residual initiator and by-products are removed by repeated washing with deionized water. The washed fluorinated polyethylene (PVDF) is dried in a vacuum drying oven at a temperature of 60-80°C and dried to a constant weight to obtain fluorinated polyethylene.

[0029] As a further solution of the present invention, the concentration of the fluorinated vinyl monomer is controlled at 0.1-1.0 mol / L, and the concentration of potassium persulfate (KPS) is 0.01-0.1 mol / L.

[0030] As a further solution of the present invention, the ammonium polyphosphate has a particle size of 100-500 nm, a density of 1.9 g / cm³, and a degree of polymerization of the ammonium polyphosphate greater than 200, and is used for synergistic effect with micro-nano antimony trioxide.

[0031] As a further solution of the present invention, the polyvinyl pyrrolidone is K30 type polyvinyl pyrrolidone with a viscosity of 5-10 mPa.s and a density of 1.2 g / cm³. Vinyl pyrrolidone monomer and potassium persulfate are reacted by adding ethanol into a reaction container, the reaction temperature is controlled between 60-80°C, the reaction is stirred evenly and then reacted for 4-8 hours to separate the polyvinyl pyrrolidone.

[0032] In a second aspect, the present invention also provides a method for preparing a halogen-free and non-toxic coal mine fire extinguishing agent, the steps of which are as follows:

[0033] 1) Weigh bio-based polyester, ultrafine magnesium silicate, antimony trioxide, modified silicate, polylactic acid, ammonium polyphosphate, nano titanium dioxide, fluorinated polymer, graphene oxide, polyurethane foam, magnesium aluminum hydrotalcite and polyvinyl pyrrolidone according to weight parts and set aside;

[0034] 2) Preliminary mixing of mixed raw materials: adding weighed bio-based polyester, polylactic acid, ammonium polyphosphate, and polyvinyl pyrrolidone into a stirrer according to the weight ratio and stirring for 5-10 minutes to premix to form a premix;

[0035] 3) gradually adding ultrafine magnesium silicate, antimony trioxide, modified silicate, nano titanium dioxide, graphene oxide, and magnesium aluminum hydrotalcite into a stirrer, and continuing stirring at a stirring speed of 200-250 r / min for 10-20 minutes, and controlling the temperature at 25° C. to obtain a stirred and mixed fire extinguishing agent composition, and transferring the mixture of the fire extinguishing agent composition to a reactor;

[0036] 4) Gradually add the fluorinated polymer to the reactor, and slowly add the polyurethane foam and stir for 10-15 minutes to evenly distribute the foam in the mixture. Put the obtained halogen-free and non-toxic coal mine fire extinguishing agent into a sealed container and store it in a dry and cool place for use.

[0037] In a third aspect, the present invention further provides a coal mine fire extinguishing product, which is manufactured based on a halogen-free and non-toxic coal mine fire extinguishing agent. The manufacturing method of the coal mine fire extinguishing product is to package the halogen-free and non-toxic coal mine fire extinguishing agent to form the required coal mine fire extinguishing product.

[0038] Compared with the prior art, the halogen-free and non-toxic fire extinguishing agent for coal mines of the present invention and its preparation method and application have the following beneficial effects:

[0039] 1. Excellent fire extinguishing performance: The fire extinguishing agent uses halogen-free and non-toxic raw materials, meets environmental protection requirements, reduces pollution to the environment, minimizes health risks to humans and animals, and can effectively inhibit combustion under high temperature conditions. Its main flame retardant ingredients, bio-based polyester and polylactic acid, can quickly form an isolation layer at high temperatures to prevent the spread of combustion, reduce the speed of flame propagation, and improve the fire extinguishing effect, especially in high-risk environments such as coal mines.

[0040] 2. Highly efficient stability and safety: In this fire extinguishing agent, the overall performance of the fire extinguishing agent is significantly enhanced through the synergistic effect between antimony trioxide, ammonium polyphosphate, nano titanium dioxide, fluorinated polymer and graphene oxide. Antimony trioxide and ammonium polyphosphate work together to promote the formation of a stable fire extinguishing structure, while nano titanium dioxide and fluorinated polymer improve the dispersion and uniformity of the material, further improving the fire extinguishing effect. The fire extinguishing agent remains stable under high temperature, high pressure and other extreme conditions, reducing safety hazards during use and ensuring the safety of coal mine operations.

[0041] 3. Efficient and easy-to-use preparation method: The fire extinguishing agent preparation method of the present invention is simple and easy to use. Through the steps of proportioning and stirring premixing, dispersion, reaction and packaging, the stirring speed, temperature and time and other parameters can be controlled, which improves the uniformity and stability of the fire extinguishing agent, ensures the high efficiency and consistency of the product, and is suitable for large-scale industrial production. All raw materials are non-toxic and harmless materials, meet environmental protection standards, and will not pollute the environment. In particular, environmentally friendly fire extinguishing agent ingredients such as bio-based polyester and ultra-fine magnesium silicate are selected to reduce the release of harmful substances and protect the environment and human health; the fire extinguishing agent is suitable for use in high-risk places such as coal mines, which can significantly reduce the probability of fire and ensure the safety of miners and the protection of life and property.

[0042] In summary, the halogen-free and non-toxic coal mine fire extinguishing agent of the present invention and its preparation method and application have the advantages of excellent fire extinguishing performance, high efficiency stability, significant flame retardant effect, environmental friendliness, etc., are suitable for the wide application of coal mine fire extinguishing products, improve the safety and reliability of coal mine production, provide effective protection for the safe production of coal mines, and have good market prospects and social value.

[0043] In order to more clearly illustrate the structural features and effects of the present invention, the present invention is described in detail below in conjunction with specific embodiments. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is further described in detail below in conjunction with specific implementation methods.

[0045] Embodiment 1: The embodiment of the present invention provides a halogen-free and non-toxic fire extinguishing agent for coal mines, comprising the following raw materials in parts by weight:

[0046] 9 parts of bio-based polyester; 20 parts of ultrafine magnesium silicate; 20 parts of antimony trioxide; 35 parts of modified silicate; 8 parts of polylactic acid; 35 parts of ammonium polyphosphate; 3 parts of nano titanium dioxide; 2 parts of fluorinated polymer; 3 parts of graphene oxide; 20 parts of polyurethane foam; 25 parts of magnesium aluminum hydrotalcite, and 3 parts of polyvinyl pyrrolidone.

[0047] In this embodiment, the type of the bio-based polyester is polylactic acid-ethylene (PLA-EVA) copolymer, the ultrafine magnesium silicate is an ultrafine magnesium silicate powder with a particle size of 30±15nm and a specific surface area of ​​130m² / g; the particle size of antimony trioxide is 100nm to 1um, and the specific surface area is 20m² / g; the modified silicate is a modified silicate powder with an average particle size of less than 1 micron and a specific surface area greater than 100 m² / g; the silicate raw material is bentonite; the organosilane is KH-550; the coupling agent is γ-aminopropyltriethoxysilane; the fluorinated polymer is fluorinated polyethylene; the particle size of ammonium polyphosphate is 300±50nm, the density is 1.9g / cm³, and the degree of polymerization of ammonium polyphosphate is greater than 200; the polyvinyl pyrrolidone is K30 type polyvinyl pyrrolidone, with a viscosity of 7.5 mPa.s and a density of 1.2 g / cm³.

[0048] The preparation method of the modified silicate is as follows: using natural silicate mineral as silicate raw material, using a ball mill to crush the natural silicate mineral to a particle size of 50±5 microns, and sieving to obtain silicate powder with uniform particle size; dissolving organosilane as a modifier in an organic solvent to prepare a modifier solution, wherein the organic solvent is ethanol, and the prepared modifier solution has a concentration of 5%; placing the pretreated silicate powder in the modifier solution, controlling the solid-liquid ratio to 1:7, adding a coupling agent, stirring at room temperature for 1.5 hours to allow the silicate surface to fully contact the modifier, and performing ultrasonic dispersion treatment. The silicate powder was treated for 45 minutes; the impregnated silicate powder was reacted at 100°C for 3 hours in a stirred reactor, and the modifier reacted with the surface of the silicate powder through heating and stirring to form a stable modified layer; after the reaction, the modified silicate powder was separated from the solid by a vacuum filter, and washed with deionized water for 3 times to remove the unreacted modifier and other impurities; the washed modified silicate powder was dried in a drying equipment at 100°C for 5 hours, and after drying, it was crushed with a jet mill to obtain a modified silicate powder with a particle size of less than 1 micron.

[0049] Among them, fluorinated polyethylene is prepared from fluorinated vinyl monomer, and the preparation method is as follows: adding dimethylformamide as a solvent into a reactor, adding hexadecyltrimethylammonium bromide (CTAB) and phosphate buffer into the solvent, and stirring evenly; dissolving potassium persulfate (KPS) in deionized water to prepare an initiator solution; introducing fluorinated vinyl monomer into the reactor and gradually increasing the pressure to a reaction pressure of 10 MPa, and after the pressure of the fluorinated vinyl monomer reaches a predetermined value, adding the initiator solution into the reactor; controlling the temperature of the reactor at 75°C, and maintaining uniform stirring, reacting for 8 hours, and after the reaction is completed, slowly reducing the pressure to normal pressure to stop the reaction; filtering the reaction product through a filter cloth, collecting the fluorinated polyethylene solid, and repeatedly washing with deionized water to remove the residual initiator and by-products, and drying the washed fluorinated polyethylene (PVDF) in a vacuum drying oven, controlling the temperature at 75°C, and drying to constant weight to obtain fluorinated polyethylene.

[0050] The preparation method of the halogen-free and non-toxic coal mine fire extinguishing agent in this embodiment comprises the following steps:

[0051] 1) Weigh bio-based polyester, ultrafine magnesium silicate, antimony trioxide, modified silicate, polylactic acid, ammonium polyphosphate, nano titanium dioxide, fluorinated polymer, graphene oxide, polyurethane foam, magnesium aluminum hydrotalcite and polyvinyl pyrrolidone according to weight parts and set aside;

[0052] 2) Preliminary mixing of mixed raw materials: adding weighed bio-based polyester, polylactic acid, ammonium polyphosphate, and polyvinyl pyrrolidone into a stirrer according to a weight ratio and stirring for 10 minutes to premix to form a premix;

[0053] 3) adding ultrafine magnesium silicate, antimony trioxide, modified silicate, nano titanium dioxide, graphene oxide, and magnesium aluminum hydrotalcite gradually into a stirrer, and continuing stirring at a stirring speed of 250 r / min for 10 minutes, and controlling the temperature at 25° C. to obtain a stirred and mixed fire extinguishing agent composition, and transferring the mixture of the fire extinguishing agent composition into a reactor;

[0054] 4) Gradually add the fluorinated polymer to the reactor, and slowly add the polyurethane foam and stir for 15 minutes to evenly distribute the foam in the mixture. Put the obtained halogen-free and non-toxic coal mine fire extinguishing agent into a sealed container and store it in a dry and cool place for use.

[0055] Embodiment 2: The embodiment of the present invention provides a halogen-free and non-toxic fire extinguishing agent for coal mines. Different from Embodiment 1, the fire extinguishing agent comprises the following raw materials in parts by weight:

[0056] 15 parts of bio-based polyester; 23 parts of ultrafine magnesium silicate; 23 parts of antimony trioxide; 40 parts of modified silicate; 12 parts of polylactic acid; 40 parts of ammonium polyphosphate; 7 parts of nano titanium dioxide; 4 parts of fluorinated polymer; 5 parts of graphene oxide; 23 parts of polyurethane foam; 30 parts of magnesium aluminum hydrotalcite, and 5 parts of polyvinyl pyrrolidone.

[0057] In this embodiment, the silicate raw material is kaolin; and the organosilane is KH-560.

[0058] The preparation method of the halogen-free and non-toxic coal mine fire extinguishing agent in this embodiment comprises the following steps:

[0059] 1) Weigh bio-based polyester, ultrafine magnesium silicate, antimony trioxide, modified silicate, polylactic acid, ammonium polyphosphate, nano titanium dioxide, fluorinated polymer, graphene oxide, polyurethane foam, magnesium aluminum hydrotalcite and polyvinyl pyrrolidone according to weight parts and set aside;

[0060] 2) Preliminary mixing of mixed raw materials: adding weighed bio-based polyester, polylactic acid, ammonium polyphosphate, and polyvinyl pyrrolidone into a stirrer according to a weight ratio and stirring for 7 minutes to premix to form a premix;

[0061] 3) gradually adding ultrafine magnesium silicate, antimony trioxide, modified silicate, nano titanium dioxide, graphene oxide, and magnesium aluminum hydrotalcite into a stirrer, and continuing stirring at a stirring speed of 230 r / min for 15 minutes, and controlling the temperature at 25° C. to obtain a stirred and mixed fire extinguishing agent composition, and transferring the mixture of the fire extinguishing agent composition into a reactor;

[0062] 4) Gradually add the fluorinated polymer to the reactor, and slowly add the polyurethane foam and stir for 10 minutes to evenly distribute the foam in the mixture. Put the obtained halogen-free and non-toxic coal mine fire extinguishing agent into a sealed container and store it in a dry and cool place for use.

[0063] Embodiment 3: The embodiment of the present invention provides a halogen-free and non-toxic fire extinguishing agent for coal mines. Different from Embodiment 1, the fire extinguishing agent comprises the following raw materials in parts by weight:

[0064] 15 parts of bio-based polyester; 25 parts of ultrafine magnesium silicate; 25 parts of antimony trioxide; 40 parts of modified silicate; 11 parts of polylactic acid; 40 parts of ammonium polyphosphate; 6 parts of nano titanium dioxide; 5 parts of fluorinated polymer; 6 parts of graphene oxide; 25 parts of polyurethane foam; 30 parts of magnesium aluminum hydrotalcite and 6 parts of polyvinyl pyrrolidone.

[0065] In this embodiment, the silicate raw material is mica.

[0066] The preparation method of the halogen-free and non-toxic coal mine fire extinguishing agent in this embodiment comprises the following steps:

[0067] 1) Weigh bio-based polyester, ultrafine magnesium silicate, antimony trioxide, modified silicate, polylactic acid, ammonium polyphosphate, nano titanium dioxide, fluorinated polymer, graphene oxide, polyurethane foam, magnesium aluminum hydrotalcite and polyvinyl pyrrolidone according to weight parts and set aside;

[0068] 2) Preliminary mixing of mixed raw materials: adding weighed bio-based polyester, polylactic acid, ammonium polyphosphate, and polyvinyl pyrrolidone into a stirrer according to a weight ratio and stirring for 10 minutes to premix to form a premix;

[0069] 3) adding ultrafine magnesium silicate, antimony trioxide, modified silicate, nano titanium dioxide, graphene oxide, and magnesium aluminum hydrotalcite gradually into a stirrer, and continuing stirring at a stirring speed of 200 r / min for 20 minutes, and controlling the temperature at 25° C. to obtain a stirred and mixed fire extinguishing agent composition, and transferring the mixture of the fire extinguishing agent composition into a reactor;

[0070] 4) Gradually add the fluorinated polymer to the reactor, and slowly add the polyurethane foam and stir for 15 minutes to evenly distribute the foam in the mixture. Put the obtained halogen-free and non-toxic coal mine fire extinguishing agent into a sealed container and store it in a dry and cool place for use.

[0071] Embodiment 4: The embodiment of the present invention provides a halogen-free and non-toxic fire extinguishing agent for coal mines. Different from Embodiment 1, the fire extinguishing agent comprises the following raw materials in parts by weight:

[0072] 18 parts of bio-based polyester; 27 parts of ultrafine magnesium silicate; 27 parts of antimony trioxide; 43 parts of modified silicate; 12 parts of polylactic acid; 43 parts of ammonium polyphosphate; 7 parts of nano titanium dioxide; 6 parts of fluorinated polymer; 8 parts of graphene oxide; 18 parts of polyurethane foam; 32 parts of magnesium aluminum hydrotalcite and 8 parts of polyvinyl pyrrolidone.

[0073] In this embodiment, the silicate raw material is bentonite and kaolin in a weight ratio of 1:1; the organosilane is KH-560.

[0074] The preparation method of the halogen-free and non-toxic coal mine fire extinguishing agent in this embodiment comprises the following steps:

[0075] 1) Weigh bio-based polyester, ultrafine magnesium silicate, antimony trioxide, modified silicate, polylactic acid, ammonium polyphosphate, nano titanium dioxide, fluorinated polymer, graphene oxide, polyurethane foam, magnesium aluminum hydrotalcite and polyvinyl pyrrolidone according to weight parts and set aside;

[0076] 2) Preliminary mixing of mixed raw materials: adding weighed bio-based polyester, polylactic acid, ammonium polyphosphate, and polyvinyl pyrrolidone into a stirrer according to a weight ratio and stirring for 10 minutes to premix to form a premix;

[0077] 3) adding ultrafine magnesium silicate, antimony trioxide, modified silicate, nano titanium dioxide, graphene oxide, and magnesium aluminum hydrotalcite gradually into a stirrer, and continuing stirring at a stirring speed of 250 r / min for 10 minutes, and controlling the temperature at 25° C. to obtain a stirred and mixed fire extinguishing agent composition, and transferring the mixture of the fire extinguishing agent composition into a reactor;

[0078] 4) Gradually add the fluorinated polymer to the reactor, and slowly add the polyurethane foam and stir for 10 minutes to evenly distribute the foam in the mixture. Put the obtained halogen-free and non-toxic coal mine fire extinguishing agent into a sealed container and store it in a dry and cool place for use.

[0079] Embodiment 5: The embodiment of the present invention provides a halogen-free and non-toxic fire extinguishing agent for coal mines. Different from Embodiment 1, the fire extinguishing agent comprises the following raw materials in parts by weight:

[0080] 21 parts of bio-based polyester; 30 parts of ultrafine magnesium silicate; 30 parts of antimony trioxide; 45 parts of modified silicate; 14 parts of polylactic acid; 45 parts of ammonium polyphosphate; 10 parts of nano titanium dioxide; 8 parts of fluorinated polymer; 10 parts of graphene oxide; 30 parts of polyurethane foam; 35 parts of magnesium aluminum hydrotalcite, and 10 parts of polyvinyl pyrrolidone.

[0081] The preparation method of the halogen-free and non-toxic coal mine fire extinguishing agent in this embodiment comprises the following steps:

[0082] 1) Weigh bio-based polyester, ultrafine magnesium silicate, antimony trioxide, modified silicate, polylactic acid, ammonium polyphosphate, nano titanium dioxide, fluorinated polymer, graphene oxide, polyurethane foam, magnesium aluminum hydrotalcite and polyvinyl pyrrolidone according to weight parts and set aside;

[0083] 2) Preliminary mixing of mixed raw materials: adding weighed bio-based polyester, polylactic acid, ammonium polyphosphate, and polyvinyl pyrrolidone into a stirrer according to a weight ratio and stirring for 5 minutes to premix to form a premix;

[0084] 3) adding ultrafine magnesium silicate, antimony trioxide, modified silicate, nano titanium dioxide, graphene oxide, and magnesium aluminum hydrotalcite gradually into a stirrer, and continuing stirring at a stirring speed of 200 r / min for 20 minutes, and controlling the temperature at 25° C. to obtain a stirred and mixed fire extinguishing agent composition, and transferring the mixture of the fire extinguishing agent composition into a reactor;

[0085] 4) Gradually add the fluorinated polymer to the reactor, and slowly add the polyurethane foam and stir for 15 minutes to evenly distribute the foam in the mixture. Put the obtained halogen-free and non-toxic coal mine fire extinguishing agent into a sealed container and store it in a dry and cool place for use.

[0086] Comparative Example 1

[0087] A fire extinguishing agent for coal mines, comprising the following raw materials in parts by weight:

[0088] 25 parts of ultrafine magnesium silicate; 25 parts of antimony trioxide; 40 parts of modified silicate; 11 parts of polylactic acid; 40 parts of ammonium polyphosphate; 6 parts of nano titanium dioxide; 5 parts of fluorinated polymer; 6 parts of graphene oxide; 25 parts of polyurethane foam; 30 parts of magnesium aluminum hydrotalcite and 6 parts of polyvinyl pyrrolidone. Among them, the halogen-free and non-toxic coal mine fire extinguishing agent does not contain bio-based polyester.

[0089] Comparative Example 2

[0090] A fire extinguishing agent for coal mines, comprising the following raw materials in parts by weight:

[0091] 15 parts of bio-based polyester; 25 parts of antimony trioxide; 40 parts of modified silicate; 11 parts of polylactic acid; 40 parts of ammonium polyphosphate; 6 parts of nano titanium dioxide; 5 parts of fluorinated polymer; 6 parts of graphene oxide; 25 parts of polyurethane foam; 30 parts of magnesium aluminum hydrotalcite and 6 parts of polyvinyl pyrrolidone. Among them, the halogen-free and non-toxic coal mine fire extinguishing agent does not contain ultrafine magnesium silicate.

[0092] Comparative Example 3

[0093] A fire extinguishing agent for coal mines, comprising the following raw materials in parts by weight:

[0094] 25 parts of antimony trioxide; 40 parts of modified silicate; 11 parts of polylactic acid; 40 parts of ammonium polyphosphate; 6 parts of nano titanium dioxide; 5 parts of fluorinated polymer; 6 parts of graphene oxide; 25 parts of polyurethane foam; 30 parts of magnesium aluminum hydrotalcite and 6 parts of polyvinyl pyrrolidone. Among them, the halogen-free and non-toxic coal mine fire extinguishing agent does not contain bio-based polyester and ultrafine magnesium silicate, and the preparation process of comparative examples 1-3 is the same as that of example 3.

[0095] Effect verification:

[0096] The halogen-free and non-toxic coal mine fire extinguishing agents prepared in Examples 1-5 and the coal mine fire extinguishing agents prepared in Comparative Examples 1-3 were subjected to the following tests:

[0097] (1) Fire extinguishing performance test

[0098] Test items: Fire extinguishing time and fire extinguishing efficiency.

[0099] Test method: Select the fire extinguishing agents prepared in Examples 1-5 and Comparative Examples 1-3, and test the fire extinguishing time and fire extinguishing efficiency of the fire extinguishing agents using a standard fire source according to GB 25207-2010 standard. Spray the fire extinguishing agents prepared in Examples 1-5 and Comparative Examples 1-3 onto the fire source to cover the fire source to form a flame retardant barrier.

[0100] See Table 1 for test data:

[0101] Table 1 Test data table of fire extinguishing performance test

[0102]

[0103] Test results: The fire extinguishing time of Examples 1-5 was all within 30 seconds, and the fire extinguishing efficiency was over 98%; the fire extinguishing time of the comparative example was all over 60 seconds, and the fire extinguishing efficiency was less than 70%.

[0104] (2) Toxicity testing

[0105] Test Item: Toxicity of fire extinguishing agent.

[0106] Test method: The fire extinguishing agents prepared in Examples 1-5 and Comparative Examples 1-3 were selected, and the toxicity of the fire extinguishing agents was evaluated by an acute toxicity test on mice according to GB / T 20285-2019 standard. The acute toxicity and skin irritation of the fire extinguishing agents to mice were evaluated by an acute oral toxicity test and a skin irritation test.

[0107] Test results: The fire extinguishing agents prepared in Examples 1-5 and Comparative Examples 1-3 were tested and the toxicity levels were all non-toxic, the LD50 values ​​(mg / kg), and the skin irritation levels (non-irritating) were shown in Table 2.

[0108] Table 2 Toxicity test results of fire extinguishing agents

[0109]

[0110] (3) Thermal stability test

[0111] Test items: thermal stability and storage stability test.

[0112] Test method: Select the fire extinguishing agents for coal mines prepared in Examples 1-5 and Comparative Examples 1-3, measure the thermal decomposition temperature and physical property changes of the fire extinguishing agents under different temperature conditions, and measure the physical and chemical property changes of the fire extinguishing agents under different storage conditions.

[0113] Test result data: Examples 1-5 obtained a storage stability time of more than 365 days, and the thermal decomposition temperature was greater than 290°C, while Comparative Examples 1-3 only obtained a storage stability time of 180 days, and the thermal decomposition temperature was less than 250°C, as shown in Table 3.

[0114] Table 3 Thermal stability and storage stability test results

[0115]

[0116] It can be seen from the above test results that the halogen-free and non-toxic coal mine fire extinguishing agents prepared in Examples 1-5 are superior to the fire extinguishing agents in Comparative Examples 1-3 in terms of fire extinguishing performance, toxicity, thermal stability and storage stability, verifying the excellent performance and practical application effect of the halogen-free and non-toxic coal mine fire extinguishing agents.

[0117] The halogen-free and non-toxic coal mine fire extinguishing agent of the present invention and its preparation method and application have the advantages of excellent fire extinguishing performance, high-efficiency stability, significant flame retardant effect, environmental friendliness, etc., are suitable for the wide application of coal mine fire extinguishing products, improve the safety and reliability of coal mine production, provide effective protection for the safe production of coal mines, and have good market prospects and social value.

[0118] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A halogen-free and non-toxic fire extinguishing agent for coal mines, characterized in that: The invention comprises the following raw materials in parts by weight: 9-21 parts of bio-based polyester; 20-30 parts of ultrafine magnesium silicate; 20-30 parts of antimony trioxide; 35-45 parts of modified silicate; 8-14 parts of polylactic acid; 35-45 parts of ammonium polyphosphate; 3-10 parts of nano titanium dioxide; 2-8 parts of fluorinated polymer; 3-10 parts of graphene oxide; 20-30 parts of polyurethane foam; 25-35 parts of magnesium aluminum hydrotalcite, 3-10 parts of polyvinyl pyrrolidone; The bio-based polyester is a polylactic acid-ethylene copolymer having a glass transition temperature of 55-65° C., and forms a carbonized layer for blocking the transfer of flames and heat at a high temperature greater than the glass transition temperature; The modified silicate is a modified silicate powder with an average particle size of less than 1 micron and a specific surface area of ​​more than 100 m² / g. The preparation method of the modified silicate is: Using natural silicate minerals as silicate raw materials, using a ball mill to crush the natural silicate minerals to a particle size of 10-100 microns, and sieving to obtain silicate powder with uniform particle size; Dissolving organosilane as a modifier in an organic solvent to prepare a modifier solution, wherein the organic solvent is ethanol and the prepared modifier solution has a concentration of 1%-10%; The pretreated silicate powder is placed in a modifier solution, the solid-liquid ratio is controlled to be 1:5 to 1:10, and a coupling agent is added, and stirred at room temperature for 1-2 hours to allow the silicate surface to fully contact the modifier, and ultrasonic dispersion treatment is performed for 30-60 minutes; The impregnated silicate powder is subjected to a reaction treatment at 80-120° C. for 2-4 hours using a stirred reactor. Through heating and stirring, the modifier reacts with the surface of the silicate powder to form a stable modified layer; After the reaction is completed, the modified silicate powder is separated from the solid by a vacuum filter and washed 2-3 times with deionized water to remove the unreacted modifier and other impurities; The washed modified silicate powder is dried in a drying device at a drying temperature of 100-120° C. for 4-6 hours, and then crushed using a jet mill to obtain a modified silicate powder with a particle size of less than 1 μm; The fluorinated polymer is fluorinated polyethylene, which is prepared from fluorinated vinyl monomers by the following preparation method: Add dimethylformamide as a solvent into a reaction kettle, add a surfactant and a buffer into the solvent, and stir evenly, wherein the surfactant is hexadecyltrimethylammonium bromide and the buffer is a phosphate buffer; Dissolve potassium persulfate in deionized water to prepare an initiator solution; Adding ethylene fluoride monomer into the reactor and gradually increasing the pressure to a reaction pressure of 5-10 MPa, and after the pressure of the ethylene fluoride monomer reaches a predetermined value, adding an initiator solution into the reactor; The temperature of the reactor was controlled at 50-90°C and stirred evenly. The reaction was continued for 4-12 hours. After the reaction was completed, the pressure was slowly reduced to normal pressure to stop the reaction. The reaction product is filtered through a filter cloth, the fluorinated polyethylene solid is collected, and the residual initiator and by-products are removed by repeated washing with deionized water. The washed fluorinated polyethylene is dried in a vacuum drying oven at a temperature of 60-80° C. and dried to a constant weight to obtain fluorinated polyethylene.

2. The halogen-free and non-toxic fire extinguishing agent for coal mines according to claim 1, characterized in that: The polylactic acid-ethylene copolymer is prepared by converting biomass raw materials into lactic acid through microbial fermentation, and the lactic acid generates oligolactic acid through a condensation reaction. Under the action of a tin catalyst, a high molecular weight polylactic acid and ethylene-vinyl acetate copolymer monomer are generated through a ring-opening polymerization reaction, and copolymerization reaction is carried out at 180-200° C. and 1-5 MPa pressure. The copolymerization reaction is catalyzed by benzoyl peroxide, unreacted monomers and oligomers are removed, and the copolymer is dried to a water content of less than 0.1%, and the dried copolymer is crushed into powder or granules to obtain the product.

3. The halogen-free and non-toxic fire extinguishing agent for coal mines according to claim 2, characterized in that: The biomass raw material is corn starch or sugar cane, the polylactic acid-ethylene copolymer is copolymerized by PLA and EVA, and the melting point of the PLA-EVA copolymer is within the range of 160-180°C.

4. The halogen-free and non-toxic fire extinguishing agent for coal mines according to claim 3, characterized in that: The ultrafine magnesium silicate is an ultrafine magnesium silicate powder with a particle size of 15-50nm and a specific surface area of ​​130m² / g; the antimony trioxide has a particle size of 100nm to 1um and a specific surface area of ​​20m² / g.

5. The halogen-free and non-toxic fire extinguishing agent for coal mines according to claim 4, characterized in that: The polylactic acid is a polylactic acid powder prepared by ring-opening polymerization of lactic acid monomers in the presence of a tin catalyst at a temperature of 130-180° C. for 10-30 hours.

6. The halogen-free and non-toxic fire extinguishing agent for coal mines according to claim 5, characterized in that: The particle size of the ammonium polyphosphate is 100-500nm, the density is 1.9g / cm³, and the degree of polymerization of the ammonium polyphosphate is greater than 200; the polyvinyl pyrrolidone is K30 type polyvinyl pyrrolidone, the viscosity is 5-10 mPa.s, and the density is 1.2 g / cm³. Vinyl pyrrolidone monomer and potassium persulfate are reacted by adding ethanol into a reaction container, the reaction temperature is controlled between 60-80°C, the reaction is uniformly stirred and reacted for 4-8 hours, and the polyvinyl pyrrolidone is separated.

7. A method for preparing the halogen-free and non-toxic fire extinguishing agent for coal mines as claimed in any one of claims 1 to 6, characterized in that: Here are the steps: 1) Weigh bio-based polyester, ultrafine magnesium silicate, antimony trioxide, modified silicate, polylactic acid, ammonium polyphosphate, nano titanium dioxide, fluorinated polymer, graphene oxide, polyurethane foam, magnesium aluminum hydrotalcite and polyvinyl pyrrolidone according to weight parts and set aside; 2) Preliminary mixing of mixed raw materials: adding weighed bio-based polyester, polylactic acid, ammonium polyphosphate, and polyvinyl pyrrolidone into a stirrer according to the weight ratio and stirring for 5-10 minutes to premix to form a premix; 3) gradually adding ultrafine magnesium silicate, antimony trioxide, modified silicate, nano titanium dioxide, graphene oxide, and magnesium aluminum hydrotalcite into a stirrer, and continuing stirring at a stirring speed of 200-250 r / min for 10-20 minutes, and controlling the temperature at 25° C. to obtain a stirred and mixed fire extinguishing agent composition, and transferring the mixture of the fire extinguishing agent composition to a reactor; 4) Gradually add the fluorinated polymer to the reactor, and slowly add the polyurethane foam and stir for 10-15 minutes to evenly distribute the foam in the mixture. Put the obtained halogen-free and non-toxic coal mine fire extinguishing agent into a sealed container and store it in a dry and cool place for use.

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