Temperature-sensitive coating material for early warning of fire and preparation method of temperature-sensitive coating material

Abstract

The invention relates to the technical field of fire safety, and particularly discloses a temperature-sensitive coating material for early warning of a fire and a preparation method of the temperature-sensitive coating material. The temperature-sensitive coating material comprises 12-20 parts of a temperature-sensitive material, 80-100 parts of a curing agent, 4-28 parts of a surface-modified heat-conducting filler, 2-14 parts of a modifier and 240-300 parts of an organic prepolymer. The temperature-sensitive coating is applied to the surface of a base body such as a mine conveyor belt, an electronic element and wall cloth which are prone to being heated to cause fire disasters for temperature-sensitive modification, when the temperature of the environment or equipment is increased abnormally, the heat-conducting filler in the temperature-sensitive coating can improve the heat-conducting property of the coating, and meanwhile, a porous structure is formed in the coating, so that the heat-conducting property of the coating is improved. And the temperature-sensitive material in the coating is promoted to be quickly released together, and the detector detects the gas and gives out early warning, so that advanced early warning before a fire disaster occurs is realized, and the fire safety of the material and equipment is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of fire safety, and specifically discloses a temperature-sensitive coating material for early warning of fire and a preparation method thereof. Background Art

[0002] The abnormal temperature accumulation during the use of mining conveyor belts, electronic components, lithium batteries and other equipment reaches the ignition point, which is the main cause of fire. Therefore, advance warning before the ignition point is crucial for fire prevention and control. At present, my country mainly uses temperature sensors, CO sensors, smoke sensors and other sensing technologies to achieve fire monitoring and early warning. However, the temperature sensor cannot achieve the purpose of early prediction of fire due to the influence of the installation position; when the CO sensor and smoke detector detect the fire information, the fire has entered the initial combustion stage. Therefore, none of the above methods can achieve advance warning of fire in the early stage of the fire, and cannot provide buffer time for timely fire fighting and personnel evacuation. Therefore, the research and development of materials that can provide advance warning of fire is of great significance to fire safety.

[0003] Materials such as electronic components, wall coverings, and transport belts all have special performance requirements, and it is difficult to directly modify them to be temperature-sensitive. Therefore, coating the surface of materials and equipment is an effective way to solve the problem. Currently, low-cost polyurethane has been widely used in the fields of coatings and adhesives because of its high activity and high flexibility in terms of formulation, application technology, mechanical properties, bonding properties, and weathering resistance. However, polyurethane does not have temperature-sensitive decomposition characteristics, and its thermal conductivity is low, so it cannot dissipate accumulated heat in time. For this reason, the present invention proposes a temperature-sensitive coating material and preparation method for early fire warning, which is coated for the above-mentioned application scenarios to achieve advanced fire warning. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a temperature-sensitive coating material for early warning of fire and a preparation method thereof. Organic ammonium and organic materials that are easily decomposed at low temperature are selected as the base materials of the temperature-sensitive coating for fire warning, and thermal conductive fillers are used to enhance the porosity and heat transfer rate of the temperature-sensitive coating to form a temperature-sensitive coating. The temperature-sensitive coating is applied to the surface of substrates that are susceptible to heat and fire, such as mine conveyor belts, electronic components, and wall cloths, for temperature-sensitive modification. When the environment or equipment is abnormally heated, the thermal conductive fillers in the temperature-sensitive coating can increase the thermal conductivity of the coating, and at the same time, a porous structure is formed inside the coating, which jointly promotes the rapid release of the temperature-sensitive material inside the coating. The detector detects the gas and issues a warning, so as to achieve an advance warning before the fire occurs and ensure the fire safety of materials and equipment.

[0005] The specific technical solutions adopted are:

[0006] A temperature-sensitive coating material for early warning of fire, comprising 12 to 20 parts of temperature-sensitive material, 80 to 100 parts of curing agent, 4 to 28 parts of surface-modified thermal conductive filler, 2 to 14 parts of modifier and 240 to 300 parts of organic prepolymer. When used, the temperature-sensitive coating is applied to the substrate surface of mine conveyor belts, electronic components and wall cloth for temperature-sensitive modification. When the environment or equipment is abnormally heated, the temperature-sensitive material releases gas due to heat, and the detector detects the gas and issues an early warning.

[0007] Preferably, the temperature-sensitive material is an easily decomposable ammonium salt, and the easily decomposable ammonium salt is one of ammonium carbamate and ammonium bicarbonate, or a mixture of the two.

[0008] Preferably, the surface-modified thermally conductive filler is improved by a modifier, and the mass ratio of the modifier to the thermally conductive filler is 1:1.06-2.78. The modified thermally conductive filler has better compatibility and can effectively increase the thermal conductivity and porosity of the coating.

[0009] Preferably, the thermally conductive filler is a mixture of one or more of silicon carbide, boron nitride, carbon nanotubes, metal nanoparticles, and conductive polymers.

[0010] Preferably, the curing agent is a low molecular weight polyol or polyamine, wherein the low molecular weight means a viscosity average molecular weight not exceeding 4000.

[0011] Preferably, the temperature-sensitive coating is applied on the surface of the substrate with a surface adhesive thickness of 0.5 to 5 mm, and is left to stand until the material is completely solidified.

[0012] Preferably, the gas detector is an ammonia and CO all-in-one detector with a detection limit of ≤1ppm.

[0013] A method for preparing a temperature-sensitive coating material for early fire warning comprises the following steps:

[0014] Firstly, placing the thermal conductive filler in an ethanol aqueous solution containing 5 wt% of a modifier, reacting at 60 to 80° C. and a stirring speed of 300 rpm for 2 to 4 hours, and then filtering, drying and grinding to obtain a modified thermal conductive filler;

[0015] Then, the surface-modified thermal conductive filler is mechanically stirred with the temperature-sensitive material and the curing agent to form a powder;

[0016] Finally, the powder and the organic prepolymer are mixed at a high speed of 300 to 400 rpm for a stirring time of 0.2 to 0.5 h to obtain a temperature-sensitive coating material for early fire warning.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a temperature-sensitive coating material and preparation method for early warning of fire, wherein low-temperature easily decomposable organic ammonium and organic materials are selected as the base material of the temperature-sensitive coating for fire warning, and a thermally conductive filler is used to enhance the porosity and heat transfer rate of the temperature-sensitive coating to form the temperature-sensitive coating. The temperature-sensitive coating is applied to the surface of objects such as mine conveyor belts, electronic components, and wall cloths for temperature-sensitive modification. When the environment or equipment is abnormally heated, the thermally conductive filler in the temperature-sensitive coating can increase the thermal conductivity of the coating, and at the same time, a porous structure is formed inside the coating, which jointly promotes the rapid release of the temperature-sensitive material inside the coating. The detector detects the gas and issues an early warning, thereby achieving an advance warning before a fire occurs and ensuring the fire safety of materials and equipment.

[0019] The preparation method of the invention is simple, the conditions are easy to achieve, the application method is simple, and it can be promoted on a large scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a comparison chart of the gas generation when ammonium carbamate and the temperature-sensitive coating are heated in Example 1 of the present invention. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, ordinary technicians in this field can also make several improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the scope of protection of the present invention.

[0022] Unless otherwise specified, the raw materials, instruments and other supplies used in the present invention can be obtained through conventional channels.

[0023] Example 1

[0024] A temperature-sensitive coating material for early fire warning comprises a temperature-sensitive material, a curing agent, a surface-modified thermally conductive filler, a modifier and an organic prepolymer; wherein the surface-modified thermally conductive filler is improved by the modifier.

[0025] A method for preparing a temperature-sensitive coating for early fire warning comprises the following steps:

[0026] S1. Mixing 10 parts of a silicon carbide thermally conductive filler with 5 parts of a silane coupling agent to modify the surface of the thermally conductive filler;

[0027] S2. Grind 3.2 parts of the surface-modified silicon carbide thermal conductive filler obtained in step S1 and 9.6 parts of ammonium carbamate into powder, mechanically stir with 80 parts of curing agent for 0.2 h to fully disperse the powder, and finally add it to 240 parts of polyurethane prepolymer and mix at high speed for 0.1 h to obtain a temperature-sensitive coating.

[0028] Among them, the mixing method of the thermal conductive filler and the silane coupling agent in S1 is: placing silicon carbide powder in an ethanol aqueous solution containing 5wt% of the silane coupling agent (mass ratio is 7:1), reacting at 70°C at a stirring speed of 300rpm for 4 hours, and obtaining modified silicon carbide by filtering, drying and grinding.

[0029] The ammonium carbamate in S2 is a white crystal with a purity greater than 97%. The pyrolysis temperature is 59°C, and the pyrolysis products are ammonia and carbon dioxide.

[0030] The organic prepolymer is a polyurethane prepolymer containing an -NCO terminal group, specifically an HDI trimer;

[0031] The curing agent is a low molecular weight polyol, specifically a polyether polyol.

[0032] The temperature-sensitive coating is applied to a part of the mine conveyor belt for temperature-sensitive modification. The thickness of the surface adhesive is 3mm, and the material is left to stand until it is completely solidified. A gas detector for detecting ammonia is installed near the temperature-sensitive modified coating. When the environment or equipment heats up abnormally, the temperature-sensitive material releases gas due to heat, and the detector detects the gas and issues an early warning.

[0033] Gas detectors can be installed near the mine conveyor belt as needed. They can be ammonia and CO all-in-one detectors with a detection limit of 0.01ppm.

[0034] Example 2

[0035] A method for preparing a temperature-sensitive coating for early fire warning, which is different from Example 1 in that: 9.6 parts of surface-modified silicon carbide thermal conductive filler and 9.6 parts of ammonium carbamate are fully ground into powder, mechanically stirred with 80 parts of a curing agent for 0.2 h to fully disperse the powder, and finally added to 240 parts of a polyurethane prepolymer and mixed at high speed for 0.1 h to obtain a temperature-sensitive coating.

[0036] Other unmentioned places are the same as those in Example 1.

[0037] Embodiment 3:

[0038] A method for preparing a temperature-sensitive coating for early fire warning, which is different from Example 1 in that: 16 parts of surface-modified silicon carbide thermal conductive filler and 9.6 parts of ammonium carbamate are fully ground into powder, then mechanically stirred with 80 parts of a curing agent for 0.2 h to fully disperse the powder, and finally added to 240 parts of a polyurethane prepolymer and mixed at high speed for 0.1 h to obtain a temperature-sensitive coating.

[0039] Other unmentioned places are the same as those in Example 1.

[0040] Embodiment 4:

[0041] A method for preparing a temperature-sensitive coating for early fire warning, which is different from Example 1 in that: 22.4 parts of surface-modified silicon carbide thermal conductive filler and 9.6 parts of ammonium carbamate are fully ground into powder, and then mechanically stirred with 80 parts of a curing agent for 0.2 h to fully disperse the powder, and finally added to 240 parts of a polyurethane prepolymer and mixed at high speed for 0.1 h to obtain a temperature-sensitive coating.

[0042] Other unmentioned places are the same as those in Example 1.

[0043] Performance Test:

[0044] The temperature sensitive coatings for early warning of fire prepared in Examples 1 to 4 were tested for index gas using a programmed temperature gas chromatograph. The test results are as follows: Figure 1 As shown. Figure 1 It can be seen that the decomposition temperature of ammonium carbamate is 36°C, reaching the highest at 50°C. The decomposition temperature points of the four samples obtained in Examples 1-4 are shifted backward compared to ammonium carbamate. This is because polyurethane has no temperature-sensitive decomposition characteristics, and its thermal conductivity is low and its density is strong, so that the temperature-sensitive material cannot be decomposed and released in time. At the same time, with the increase of the content of surface-modified thermally conductive filler in the coating, the temperature of the index gas released by the decomposition of the thermosensitive material moves forward. When the content is 7% (Example 4), the release temperature point reaches 49°C, which is 26°C earlier than the content of 1% (Example 1). The reason is that the thermally conductive filler can increase the thermal conductivity of the coating, and at the same time form a porous structure inside the coating, enhance the heat transfer efficiency of the coating, and jointly promote the rapid release of the temperature-sensitive material inside the coating, so that the detector can detect the gas and issue an early warning, so as to achieve an advance warning before the fire occurs and ensure the fire safety of materials and equipment.

[0045] Example 5

[0046] A method for preparing a temperature-sensitive coating for early fire warning comprises the following steps:

[0047] S1. Mixing 10 parts of a silicon carbide thermally conductive filler with 5 parts of a silane coupling agent to modify the surface of the thermally conductive filler;

[0048] S2. Grind 4 parts of the surface-modified silicon carbide thermal conductive filler obtained in step S1 and 12 parts of ammonium carbamate into powder, mechanically stir with 80 parts of curing agent for 0.2 h to fully disperse the powder, and finally add it to 240 parts of polyurethane prepolymer and mix at high speed for 0.1 h to obtain a temperature-sensitive coating.

[0049] The organic prepolymer is polyacrylic acid;

[0050] The temperature-sensitive coating is applied to the local area of ​​the mine conveyor belt for temperature-sensitive modification. The thickness of the surface adhesive is 5mm, and it is left to stand until the material is completely solidified. A gas detector for detecting ammonia is installed near the temperature-sensitive modified coating. When the environment or equipment is abnormally heated, the temperature-sensitive material releases gas due to heat. The detector is an ammonia and CO all-in-one detector with a detection limit of 0.01ppm. The detector detects the gas and issues an early warning.

[0051] Other unmentioned places are the same as those in Example 1.

[0052] Example 6 A method for preparing a temperature-sensitive coating for early warning of fire, which is different from Example 5 in that: the thermal conductive filler is boron nitride; 20 parts of the thermal conductive filler are mixed with 5 parts of a silane coupling agent to modify the surface of the thermal conductive filler;

[0053] 20 parts of surface-modified thermal conductive filler and 20 parts of ammonium bicarbonate were fully ground into powder, and then mechanically stirred with 100 parts of curing agent for 0.2 h to fully disperse the powder. Finally, it was added to 240 parts of polyurethane prepolymer and mixed at high speed for 0.1 h to obtain a temperature-sensitive coating.

[0054] Other unmentioned parts are the same as those in Example 5.

[0055] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A temperature-sensitive coating material for early fire warning, characterized in that: The temperature-sensitive coating material includes 12 to 20 parts of temperature-sensitive material, 80 to 100 parts of curing agent, 4 to 28 parts of surface-modified thermal conductive filler, 2 to 14 parts of modifier and 240 to 300 parts of organic prepolymer. When in use, the temperature-sensitive coating is applied to the substrate surface of a mine conveyor belt, electronic components, or wall cloth for temperature-sensitive modification. When the environment or equipment experiences abnormal temperature rise, the temperature-sensitive material releases gas due to heat, and the detector detects the gas and issues an early warning.

2. A temperature-sensitive coating material for early fire warning according to claim 1, characterized in that: The temperature-sensitive material is an easily decomposable ammonium salt, and the easily decomposable ammonium salt is one of ammonium carbamate and ammonium bicarbonate or a mixture of the two.

3. The temperature-sensitive coating material for early fire warning according to claim 1, characterized in that: The surface-modified thermally conductive filler is obtained by improving the thermally conductive filler with a modifier, and the mass ratio of the modifier to the thermally conductive filler is 1:1.06-2.

78.

4. The temperature-sensitive coating material for early fire warning according to claim 3, characterized in that: The thermally conductive filler is a mixture of one or more of silicon carbide, boron nitride, carbon nanotubes, metal nanoparticles, and conductive polymers.

5. The temperature-sensitive coating material for early fire warning according to claim 3, characterized in that: The thermal conductive filler modifier is a silane coupling agent.

6. The temperature-sensitive coating material for early fire warning according to claim 1, characterized in that: The organic prepolymer is any one of a polyurethane prepolymer containing an -NCO terminal group, polyacrylic acid, and polyvinyl alcohol.

7. The temperature-sensitive coating material for early fire warning according to claim 1, characterized in that: The curing agent is a low molecular weight polyol or polyamine, wherein the low molecular weight means a viscosity average molecular weight not exceeding 4000.

8. The temperature-sensitive coating material for early fire warning according to claim 1, characterized in that: The temperature-sensitive coating is applied on the surface of the substrate with a surface adhesive thickness of 0.5 to 5 mm, and is left to stand until the material is completely solidified.

9. The temperature-sensitive coating material for early fire warning according to claim 1, characterized in that: The gas detector is an all-in-one detector for ammonia and CO, with a detection limit of ≤1ppm.

10. A method for preparing a temperature-sensitive coating material for early fire warning according to any one of claims 1 to 9, characterized in that: The steps include: Firstly, placing the thermal conductive filler in an ethanol aqueous solution containing 5 wt% of a modifier, reacting at 60-80° C. and a stirring speed of 300 rpm for 2-4 hours, and then filtering, drying and grinding to obtain a modified thermal conductive filler; Then, the surface-modified thermal conductive filler is mechanically stirred with the temperature-sensitive material and the curing agent to form a powder; Finally, the powder and the organic prepolymer are mixed at a high speed at a stirring speed of 300 to 400 rpm for a stirring time of 0.2 to 0.5 h, thereby obtaining the temperature-sensitive coating material for early warning of fire.

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