High-strength plugging fireproof adhesive capable of expanding in case of fire at low temperature and preparation method of high-strength plugging fireproof adhesive

Abstract

The invention relates to a high-strength plugging fireproof adhesive capable of expanding in case of fire at low temperature and a preparation method thereof, and belongs to a fireproof adhesive capable of expanding in case of fire. Comprising 20-30 parts of polyether polyol, 10-20 parts of quartz powder, 1-20 parts of heavy calcium powder, 0.5-2 parts of flame-retardant graphite, 20-30 parts of expanded graphite, 10-20 parts of a flame retardant, 0.5-2 parts of a thixotropic agent, 0.5-1 part of a water removal agent, a catalyst and 0.01-0.05 part of a delay catalyst. 10 to 20 parts of 4, 4 diphenylmethane diisocyanate, and 1 to 5 parts of isophorone diisocyanate. The fireproof door has the advantages that a high-strength structure can be formed, the overall strength and sealing performance are further improved, the structural fire resistance of the fireproof door is enhanced, the fireproof door can be maintained for a longer time during structural fire resistance, and the fireproof door can rapidly expand in case of fire to play roles in active fire prevention and heat transmission prevention, so that all-around fireproof protection is realized.

Description

Technical Field

[0001] The present invention belongs to a fire-expandable fireproof adhesive, and particularly relates to a high-strength low-temperature fire-expandable plugging fireproof glue and a preparation method thereof. Background Art

[0002] In the construction field, traditional fireproof plugging materials mainly consist of non-drying putty. This material has certain plasticity and fireproof performance, and can initially plug building gaps, holes and other parts, playing a simple fireproof barrier role. However, the non-drying putty has obvious limitations in terms of insufficient sealing performance, making it impossible to achieve a good sealing effect and difficult to effectively prevent the diffusion of smoke, toxic gases, etc. inside the building. This may accelerate the spread of fire during a fire and reduce the fire safety of the building. In addition, the non-drying putty also has problems with structural support. For example, for the plugging of some large holes, it is often difficult to firmly support only with non-drying putty, and additional bottom plates need to be added to assist in fixing. But in some special parts, such as areas with complex building structures or places with limited space, it is not convenient to install the bottom plate, resulting in ineffective plugging of these parts and potential fire hazards.

[0003] In the electronics industry, potting sealant is a commonly used fireproof plugging material. It can well fill the gaps and holes inside electronic devices, playing a sealing role to prevent dust, moisture, etc. from entering the device interior, thus ensuring the normal operation of electronic devices. However, when sudden situations such as short circuits occur in the circuit board, the fireproof performance of this sealant is insufficient: that is, it cannot extinguish fires actively. When the potting sealant encounters local high temperature or sparks caused by a short circuit in the circuit board, it cannot quickly react and actively extinguish the fire like a fire extinguishing material, and can only play a certain blocking role to delay the spread speed of the fire. But in some electronic devices with extremely high requirements for fire safety, this passive fireproof method may not meet the needs, and once a fire is caused by a short circuit, the device may suffer serious damage.

[0004] The development of fireproof sealing adhesives in the vehicle industry has been relatively rapid. Currently, there are mainly three categories: fireproof putty, pouring sealant, and some new composite materials. With the continuous improvement of vehicle intelligence and speed, the requirements for fireproof sealing materials are also getting higher and higher. Although traditional fireproof putty has certain fireproof performance, in vehicles running at high speeds such as high-speed trains, its performance will be greatly affected. For example, during the operation of a high-speed train, factors such as vibration and air flow inside the vehicle may cause the structure of the fireproof putty to loosen, reducing its fireproof effect. In addition, the durability of fireproof putty is relatively poor, and problems such as aging and cracking are likely to occur during long-term use, unable to continuously and effectively guarantee the fire safety of vehicles. Existing pouring sealants can meet the sealing requirements of some parts inside the vehicle, but there are obvious shortcomings in fire resistance performance. Generally, it is difficult for this kind of sealant to meet the requirement of structural fire resistance for more than 30 minutes. When a vehicle catches fire, 30 minutes is often the critical time window for personnel evacuation and emergency rescue. If the sealing material cannot maintain its structural integrity and fireproof performance within this time, it may cause the fire to spread rapidly to other parts of the vehicle, increasing the risk of casualties and property losses.

[0005] In summary, although traditional fireproof sealing adhesives have been widely used in industries such as construction, electronics, and vehicles, many problems and deficiencies have also been exposed. With the continuous improvement of fire safety requirements in various industries, developing new high-performance fireproof sealing materials to overcome the defects of existing materials has become an urgent problem to be solved. Summary of the Invention

[0006] The present invention provides a high-strength fire-expanding sealing fireproof glue for low-temperature fire and a preparation method thereof to solve the problems of poor overall strength, sealing performance, and fire resistance performance existing in current pouring sealants.

[0007] The technical solution adopted by the present invention is as follows, including raw materials with the following weight ratios: Component A: 20 - 30 parts of polyether polyol, 10 - 20 parts of quartz powder, 1 - 20 parts of heavy calcium powder, 0.5 - 2 parts of flame-retardant graphite, 20 - 30 parts of expanded graphite, 10 - 20 parts of flame retardant, 0.5 - 2 parts of thixotropic agent, 0.5 - 1 part of water remover, 0.01 - 0.05 part of catalyst, 0.01 - 0.05 part of delayed catalyst; Component B: 10 - 20 parts of 4,4-diphenylmethane diisocyanate, 1 - 5 parts of isophorone diisocyanate.

[0008] The polyether polyol is a polyether polyol with a hydroxyl value of 330, or a mixture of a polyether polyol with a hydroxyl value of 330 and a polyether polyol with a hydroxyl value of 30.

[0009] The quartz powder is 320-mesh fused silica powder or 400-mesh fused silica powder, or a mixture of fused silica powders with different mesh numbers is used.

[0010] The flame-retardant graphite is particles with a particle size of D50μm or particles with a particle size of D40μm, and the purity is above 95%.

[0011] The expanded graphite has a particle size of D0.4mm, an expansion ratio of 40 times, and an initial temperature of 150°C. It is a high-quality natural flake graphite after intercalation, water washing, and drying.

[0012] The heavy calcium powder is 200-mesh heavy calcium carbonate powder, or 320-mesh heavy calcium carbonate powder, or a mixture of the two is used.

[0013] The flame retardant is tert-butylated aryl phosphate or tert-butyl phenyl diphenyl phosphate; the thixotropic agent is a modified urea-based auxiliary agent, or a polyamide-based rheological auxiliary agent, or a polyether-modified polysiloxane-based rheological auxiliary agent; the water remover is an oxolane-based water remover or a derivative of oxolane.

[0014] The catalyst is an organic bismuth catalyst, and the content of metallic bismuth is 20±0.5; the delayed catalyst is tert-butylamine and its derivatives, and the content of the effective substance is >99%.

[0015] The 4,4-diphenylmethane diisocyanate is a mixture of 4,4-diphenylmethane diisocyanate MDI and its isomers and homologues of polyfunctional isocyanates; the isophorone diisocyanate is an alicyclic diisocyanate.

[0016] A preparation method of a high-strength and low-temperature fire-expanding plugging fireproof glue includes the following steps: Preparation of component A: (1) Weigh 10-20 parts of quartz powder, 1-20 parts of heavy calcium powder, 20-30 parts of expanded graphite, and 0.5-2 parts of flame-retardant graphite by weight, and dry them in an oven at 120°C for 3-4 days respectively; (2) Pour 20-30 parts of polyether polyol and 10-20 parts of flame retardant by weight into a stirring kettle, heat to 120°C, evacuate to 0.7mpa and stir for 2-4h; (3) Mix 0.5-2 parts of thixotropic agent by weight with the quartz powder and heavy calcium powder treated in step (1), heat to 120°C, evacuate to 0.7mpa and stir for 2-4h; (4) Add the flame-retardant graphite and expanded graphite treated in step (1) to the mixture in step (3), then heat to 120°C, evacuate to 0.7mpa and stir for 1-2h; (5) When the temperature in the stirring kettle drops to 100°C, add 0.5-1 part of water remover by weight, evacuate to 0.7mpa and stir for 1-2h; (6) When the temperature in the stirring kettle drops to 60 °C, add 0.01 - 0.05 parts by weight of catalyst and 0.01 - 0.05 parts by weight of delayed catalyst, evacuate to 0.7 mpa and stir for 1 - 2 h; Preparation of Component B Take 10 - 20 parts by weight of 4,4-diphenylmethane diisocyanate and 1 - 5 parts by weight of isophorone diisocyanate, pour them into a separate reaction kettle, evacuate to 0.7 mpa and stir for 1 - 2 h.

[0017] The beneficial effects of the present invention are as follows: The present invention uses polyurethane as the matrix. Through scientific formulation, the polyurethane matrix can form a high-strength structure, providing a solid foundation for the entire fireproof adhesive and mainly playing a role in supporting the overall structural strength. On this basis, materials such as quartz powder are added to the formula, which can significantly improve the hardness of the product, thereby further enhancing the overall strength and sealing performance. At the same time, the addition of flame retardants and flame-retardant graphite can effectively increase the oxygen index of the product and enhance its structural fire resistance, enabling the product to maintain its structure for a longer time during fire resistance. In addition, the present invention also particularly adds ultra-high magnification expanded graphite, which can rapidly expand when encountering fire, playing a role in active fire prevention and blocking heat propagation, thereby achieving all-round fire protection.

[0018] The sealing adhesive of the present invention not only has high airtightness and watertightness, can easily cope with extreme environments, but also reaches the IP68 protection level at a depth of 40 meters underwater, ensuring that the sealing performance is still maintained under deep water high pressure. In addition, this fireproof adhesive can withstand a pressure of 500 kPa for vibration life tests within the extreme temperature range of -40 °C to 80 °C, showing extraordinary stability and durability. And in terms of mechanical properties, the fireproof adhesive of the present invention also performs excellently. Its tensile strength is as high as 2.6 MPa, the shear strength reaches 2.5 MPa, and the hardness is between Shore A 85 and 90. These performance indicators provide a more reliable and efficient solution for users in hole plugging applications.

[0019] The plugging adhesive of the present invention realizes the perfect combination of passive fire prevention and active fire prevention in terms of fireproof performance. The oxygen index of the product itself is over 45%, far exceeding the industry standard, showing excellent flame retardant characteristics. More prominently, when the plugging adhesive encounters a flame, it can quickly activate the active fire prevention mechanism, with an expansion ratio of over 19 times, and starts to expand at 150 °C. When a fire occurs, the plugging adhesive will quickly expand to form a graphite layer, effectively isolating heat and oxygen, thereby playing an excellent fire extinguishing role.

[0020] In practical applications, when the thickness of the sealing glue reaches 40 mm, it can easily pass the test of Part 3 of the EN 45545-3 "Railway Applications - Fire Protection of Railway Vehicles" series of standards, with a fire resistance time exceeding 30 minutes; when the thickness increases to 60 mm, the fire resistance time can exceed 60 minutes. This not only provides a solid guarantee for the fire safety of railway vehicles, but also builds an indestructible defense line for the life and property safety of passengers and staff. Specific implementation mode

[0021] It includes raw materials with the following weight ratios: Component A: 20 - 30 parts of polyether polyol, 10 - 20 parts of quartz powder, 1 - 20 parts of heavy calcium powder, 0.5 - 2 parts of flame retardant graphite, 20 - 30 parts of expanded graphite, 10 - 20 parts of flame retardant, 0.5 - 2 parts of thixotropic agent, 0.5 - 1 part of water remover, 0.01 - 0.05 part of catalyst, 0.01 - 0.05 part of delayed catalyst; Component B 10 - 20 parts of 4,4-diphenylmethane diisocyanate, 1 - 5 parts of isophorone diisocyanate.

[0022] The polyether polyol is a polyether polyol with a hydroxyl value of 330, or a mixture of a polyether polyol with a hydroxyl value of 330 and a polyether polyol with a hydroxyl value of 30.

[0023] The quartz powder is fused silica powder with a mesh number of 320 or 400, or a mixture of fused silica powders with different mesh numbers is used.

[0024] The flame retardant graphite is particles with a particle size of D50μm or particles with a particle size of D40μm, with a purity of over 95%.

[0025] The expanded graphite has a particle size of D0.4mm, an expansion ratio of 40 times, and an initial temperature of 150°C. It is a high-quality natural flake graphite after intercalation, water washing, and drying.

[0026] The heavy calcium powder is heavy calcium carbonate powder with a mesh number of 200, or heavy calcium carbonate powder with a mesh number of 320, or a mixture of both is used.

[0027] The flame retardant is tert-butylated aryl phosphate or tert-butylphenyl diphenyl phosphate; the thixotropic agent is a modified urea-based auxiliary agent, or a polyamide-based rheological auxiliary agent, or a polyether-modified polysiloxane-based rheological auxiliary agent; the water remover is an oxolane-based water remover, or a derivative of oxolane.

[0028] The catalyst is an organic bismuth catalyst, where the content of metallic bismuth is 20 ± 0.5; the delayed catalyst is tert-butylamine and its derivatives, with an effective substance content > 99%.

[0029] The described 4,4-diphenylmethane diisocyanate is a mixture of polyfunctional isocyanates of 4,4-diphenylmethane diisocyanate MDI and its isomers and homologues; the isophorone diisocyanate is an alicyclic diisocyanate.

[0030] A preparation method of a high-strength low-temperature fire-expanded sealing fireproof glue includes the following steps: Preparation of component A: (1) Weigh 10 - 20 parts by weight of quartz powder, 1 - 20 parts by weight of heavy calcium powder, 20 - 30 parts by weight of expanded graphite, and 0.5 - 2 parts by weight of flame-retardant graphite, and dry them separately in an oven at 120°C for 3 - 4 days; (2) Pour 20 - 30 parts by weight of polyether polyol and 10 - 20 parts by weight of flame retardant into a stirring kettle, heat to 120°C, evacuate to 0.7 mpa, and stir for 2 - 4 h; (3) Mix 0.5 - 2 parts by weight of thixotropic agent with the quartz powder and heavy calcium powder treated in step (1), heat to 120°C, evacuate to 0.7 mpa, and stir for 2 - 4 h; (4) Add the flame-retardant graphite and expanded graphite treated in step (1) to the mixture in step (3), then heat to 120°C, evacuate to 0.7 mpa, and stir for 1 - 2 h; (5) When the temperature in the stirring kettle drops to 100°C, add 0.5 - 1 part by weight of water remover, evacuate to 0.7 mpa, and stir for 1 - 2 h; (6) When the temperature in the stirring kettle drops to 60°C, add 0.01 - 0.05 part by weight of catalyst and 0.01 - 0.05 part by weight of delayed catalyst, evacuate to 0.7 mpa, and stir for 1 - 2 h; Preparation of component B Take 10 - 20 parts by weight of 4,4-diphenylmethane diisocyanate and 1 - 5 parts by weight of isophorone diisocyanate, pour them into a separate reaction kettle, evacuate to 0.7 mpa, and stir for 1 - 2 h.

[0031] The present invention and its effects will be further illustrated by the following examples. Example 1

[0032] Preparation of component A: (1) Take 100 g of 320-mesh fused silica powder, 10 g of 200-mesh heavy calcium carbonate powder, 200 g of expanded graphite with a particle size of D 0.4 mm, and 5 g of flame-retardant graphite with a particle size of D 50 μm and a purity of 95%, and dry them separately in an oven at 120°C for 3 days; (2) Take 200 g of polyether polyol with a hydroxyl value of 330 and 100 g of tert-butylated aryl phosphate flame retardant, pour them into a stirring kettle, heat to 120°C, evacuate to 0.7 mpa, and stir for 2 h; (3) Take 5 g of the thixotropic agent-modified urea additive, mix it with the quartz powder and heavy calcium powder treated in step (1), heat to 120 °C, and stir under a vacuum of 0.7 mpa for 2 h; (4) Add the flame-retardant graphite and expanded graphite treated in step (1) to the mixture in step (3), then heat to 120 °C, and stir under a vacuum of 0.7 mpa for 1 h; (5) When the temperature in the stirring kettle drops to 100 °C, add 5 g of the oxolane water remover, and stir under a vacuum of 0.7 mpa for 1 h; (6) When the temperature in the stirring kettle drops to 60 °C, add 0.1 g of the organic bismuth catalyst and 0.1 g of the tert-butylamine and its derivative delay catalyst, and stir under a vacuum of 0.7 mpa for 1 h; Preparation of Component B Take 100 g of a mixture of 4,4-diphenylmethane diisocyanate MDI and its isomers and homologues of polyfunctional isocyanates and 10 g of alicyclic diisocyanate, pour them into a separate reaction kettle, and stir under a vacuum of 0.7 mpa for 1 h.

[0033] Mix Component A and Component B and stir for 1 minute. The test data are as follows: Vertex Initial curing time Full curing time Density Hardness (Shore A) Tensile strength Shear strength Expansion ratio Oxygen index IP68 (40 m underwater) Structural fire resistance time (40 mm) Negative pressure high and low temperature vibration test Test standard GB / T7123.1-2015 (Method 3) GB / T7123.1-2015 (Method 4) GB / T6343-2009 GB / T531.1-2008 GB / T528-2009 GB / T7124-2008 GB / T16807-2009 GB / T2406.2-2009 GB / T4208-2008 EN 45545-3:2013 GB / T 21563-2018 Test data 49 min 97 min 1.36 g / cm³ 87 2.7 mPa 2.7 mPa 21 times 51% Passed Passed in 45 min Passed Example 2

[0034] Preparation of Component A (1) Take 150 g of 400-mesh fused silica powder, 100 g of 320-mesh heavy calcium carbonate powder, 250 g of expanded graphite with a particle size of D 0.4 mm, and 12 g of flame-retardant graphite with a particle size of D 40 μm and a purity of 95%, and dry them in an oven at 120 °C for 3 days respectively; (2) Take 250 g of a mixture of polyether polyols with a hydroxyl value of 330 and a hydroxyl value of 30 and 150 g of tert-butylphenyl diphenyl phosphate, pour them into a stirring kettle, heat to 120 °C, and stir under a vacuum of 0.7 mpa for 3 h; (3) Take 12 g of the thixotropic agent polyamide rheology additive, mix it with the quartz powder and heavy calcium powder treated in step (1), heat to 120 °C, and stir under a vacuum of 0.7 mpa for 3 h; (4) Add the flame-retardant graphite and expanded graphite treated in step (1) to the mixture in step (3), then heat to 120 °C, and stir under a vacuum of 0.7 mpa for 1.5 h; (5) When the temperature in the stirring kettle drops to 100 °C, add 5 g of the derivative water remover of oxolane, and stir under a vacuum of 0.7 mpa for 1.5 h; (6) When the temperature in the stirring kettle drops to 60 °C, add 0.3 g of the organic bismuth catalyst and 0.3 g of the tert-butylamine and its derivative delay catalyst, and stir under a vacuum of 0.7 mpa for 1.5 h; Preparation of Component B Take 150 g of a mixture of polyfunctional isocyanates of 4,4-diphenylmethane diisocyanate (MDI) and its isomers and homologues, and 30 g of an alicyclic diisocyanate, pour them into a separate reaction kettle, evacuate to 0.7 mpa and stir for 1.5 h.

[0035] Mix component A and component B and stir for 1 minute. The test data are as follows: Vertex Initial curing time Full curing time Density Hardness (Shore A) Tensile strength Shear strength Expansion ratio Oxygen index IP68 (40 m underwater) Structural fire resistance time (40 mm) Negative pressure high and low temperature vibration test Test standard GB / T7123.1-2015 (Method 3) GB / T7123.1-2015 (Method 4) GB / T6343-2009 GB / T531.1-2008 GB / T528-2009 GB / T7124-2008 GB / T16807-2009 GB / T2406.2-2009 GB / T4208-2008 EN 45545-3:2013 GB / T 21563-2018 Test data 45 min 95 min 1.37 g / cm³ 88 2.7 mPa 2.8 mPa 21 times 52% Passed Passed in 45 min Passed Example 3

[0036] Preparation of component A: (1) Take 200 g of a mixture of fused silica powder of 320 mesh and 400 mesh, 200 g of a mixture of heavy calcium carbonate powder of 200 mesh and 320 mesh, 300 g of expanded graphite with a particle size D of 0.4 mm, and 20 g of flame retardant graphite with a particle size D of 50 μm and a purity of 95%, and dry them in an oven at 120 °C for 4 days respectively; (2) Take 300 g of polyether polyol with a hydroxyl value of 330 and 200 g of tert-butylated aryl phosphate flame retardant, pour them into a stirring kettle, heat to 120 °C, evacuate to 0.7 mpa and stir for 4 h; (3) Take 20 g of a thixotropic agent, polyether-modified polysiloxane rheological aid, mix it with the quartz powder and heavy calcium powder treated in step (1), and heat to 120 °C, evacuate to 0.7 mpa and stir for 2 h; (4) Add the flame retardant graphite and expanded graphite treated in step (1) to the mixture in step (3), then heat to 120 °C, evacuate to 0.7 mpa and stir for 2 h; (5) When the temperature in the stirring kettle drops to 100 °C, add 10 g of an oxolane water remover, evacuate to 0.7 mpa and stir for 2 h; (6) When the temperature in the stirring kettle drops to 60 °C, add 0.5 g of an organic bismuth catalyst and 0.5 g of a tert-butylamine and its derivative delay catalyst, evacuate to 0.7 mpa and stir for 2 h; Preparation of component B Take 200 g of a mixture of polyfunctional isocyanates of 4,4-diphenylmethane diisocyanate (MDI) and its isomers and homologues, and 50 g of an alicyclic diisocyanate, pour them into a separate reaction kettle, evacuate to 0.7 mpa and stir for 2 h.

[0037] Mix component A and component B and stir for 1 minute. The test data are as follows: Vertex Initial curing time Full curing time Density Hardness (Shore A) Tensile strength Shear strength Expansion ratio Oxygen index IP68 (40 m underwater) Structural fire resistance time (40 mm) Negative pressure high and low temperature vibration test Test standard GB / T7123.1-2015 (Method 3) GB / T7123.1-2015 (Method 4) GB / T6343-2009 GB / T531.1-2008 GB / T528-2009 GB / T7124-2008 GB / T16807-2009 GB / T2406.2-2009 GB / T4208-2008 EN 45545-3:2013 GB / T 21563-2018 Test data 51 min 103 min 1.41 g / cm³ 88 2.6 mPa 2.6 mPa 20 times 52% Passed Passed in 45 min Passed Example 4

[0038] Preparation of component A 1. Weigh 125 g of quartz powder, 125 g of heavy calcium powder, 7.5 g of flame retardant graphite, 300 g of expanded graphite, and dry them in an oven at 120 °C for 3 days; 2. Weigh 300 g of 330 hydroxyl value polyether polyol and 200 g of flame retardant, pour them into a stirring kettle, heat to 120 °C, evacuate to 0.7 mpa and stir for 2 h; 3. Weigh 7.5 g of thixotropic agent. At the same time, pour the dried quartz powder and heavy calcium powder into the reaction kettle, heat to 120 °C, evacuate to 0.7 mpa and stir for 2 H; 4. Pour the dried flame retardant graphite and expanded graphite into the kettle, heat to 120 °C, evacuate to 0.7 mpa and stir for 1 H; 5. Weigh 7.5 g of water removing agent, add it to the kettle when the temperature in the kettle is 100 °C, evacuate to 0.7 mpa and stir for 1 H; 6. Weigh 0.5 g of catalyst. When the temperature of the reaction kettle drops to 60 °C, add the catalyst to the reaction kettle, evacuate to 0.7 mpa and stir for 1 H; Weigh 0.45 g of delayed catalyst. When the temperature of the reaction kettle drops to 60 °C, add the catalyst to the reaction kettle, evacuate to 0.7 mpa and stir for 1 H; Preparation of Component B Weigh 170 g of 4,4-diphenylmethane diisocyanate and 50 g of isophorone diisocyanate, pour them into a separate reaction kettle, evacuate to 0.7 mpa and stir for 1 H.

[0039] Mix Component A and Component B and stir for 1 minute. The test data are as follows: Vertex Initial curing time Full curing time Density Hardness (Shore A) Tensile strength Shear strength Expansion ratio Oxygen index IP68 (40 m underwater) Structural fire resistance time (40 mm) Negative pressure high and low temperature vibration test Test standard GB / T7123.1-2015 (Method 3) GB / T7123.1-2015 (Method 4) GB / T6343-2009 GB / T531.1-2008 GB / T 528 - 2009 GB / T 7124 - 2008 GB / T 16807 - 2009 GB / T 2406.2 - 2009 GB / T 4208 - 2008 EN 45545 - 3:2013 GB / T 21563 - 2018 Test data 42 min 90 min 1.33 g / cm³ 85 2.9 mPa 2.9 mPa 22 times 52% Pass Pass in 45 min Pass Example 5

[0040] Preparation of Component A 1. Weigh 120 g of quartz powder, 150 g of heavy calcium powder, 8 g of flame retardant graphite and 300 g of expanded graphite, dry them in an oven at 120 °C for 3 days; 2. Weigh 300 g of 330 hydroxyl value polyether polyol and 100 g of flame retardant, pour them into a stirring kettle, heat to 120 °C, evacuate to 0.7 mpa and stir for 2 H; 3. Weigh 8 g of thixotropic agent. At the same time, pour the dried quartz powder and heavy calcium powder into the reaction kettle, heat to 120 °C, evacuate to 0.7 mpa and stir for 2 H; 4. Pour the dried flame retardant graphite and expanded graphite into the kettle, heat to 120 °C, evacuate to 0.7 mpa and stir for 1 H; 5. Weigh 10 g of water removing agent, add it to the kettle when the temperature in the kettle is 100 °C, evacuate to 0.7 mpa and stir for 1 H; 6. Weigh 0.4 g of catalyst. When the temperature of the reaction kettle drops to 60 °C, add the catalyst to the reaction kettle, evacuate to 0.7 mpa and stir for 1 H; Weigh 0.5 g of the delayed catalyst and add the catalyst to the reaction kettle when the temperature of the reaction kettle drops to 60 °C. Vacuumize to 0.7 mpa and stir for 1 h; Preparation of Component B Weigh 200 g of 4,4-diphenylmethane diisocyanate and 30 g of isophorone diisocyanate, pour them into a separate reaction kettle, vacuumize to 0.7 mpa and stir for 1 h.

[0041] Mix Component A and Component B and stir for 1 minute. The test data are as follows: Vertex Initial curing time Full curing time Density Hardness (Shore A) Tensile strength Shear strength Expansion ratio Oxygen index IP68 (40 m underwater) Structural fire resistance time (40 mm) Negative pressure high - low temperature vibration test Test standard GB / T 7123.1 - 2015 (Method 3) GB / T 7123.1 - 2015 (Method 4) GB / T 6343 - 2009 GB / T 531.1 - 2008 GB / T 528 - 2009 GB / T 7124 - 2008 GB / T 16807 - 2009 GB / T 2406.2 - 2009 GB / T 4208 - 2008 EN 45545 - 3:2013 GB / T 21563 - 2018 Test data 50 min 92 min 1.39 g / cm³ 88 2.7 mPa 2.7 mPa 22 times 52% Pass Pass in 45 min Pass Example 6

[0042] Preparation of Component A 1. Weigh 150 g of quartz powder, 120 g of heavy calcium powder, 7 g of flame-retardant graphite, and 250 g of expanded graphite, and dry them in an oven at 120 °C for 3 days; 2. Weigh 250 g of 330 hydroxyl value polyether polyol and 100 g of flame retardant, pour them into a stirring kettle, heat to 120 °C, vacuumize to 0.7 mpa and stir for 2 h; 3. Weigh 7.5 g of thixotropic agent, and at the same time pour the dried quartz powder and heavy calcium powder into the reaction kettle, heat to 120 °C, vacuumize to 0.7 mpa and stir for 2 h; 4. Pour the dried flame-retardant graphite and expanded graphite into the kettle, heat to 120 °C, vacuumize to 0.7 mpa and stir for 1 h; 5. Weigh 7.5 g of water scavenger and add it to the kettle when the temperature in the kettle is 100 °C, vacuumize to 0.7 mpa and stir for 1 h; 6. Weigh 0.45 g of catalyst and add the catalyst to the reaction kettle when the temperature of the reaction kettle drops to 60 °C. Vacuumize to 0.7 mpa and stir for 1 h; Weigh 0.45 g of the delayed catalyst and add the catalyst to the reaction kettle when the temperature of the reaction kettle drops to 60 °C. Vacuumize to 0.7 mpa and stir for 1 h; Preparation of Component B Weigh 200 g of 4,4-diphenylmethane diisocyanate and 30 g of isophorone diisocyanate, pour them into a separate reaction kettle, vacuumize to 0.7 mpa and stir for 1 h.

[0043] Mix Component A and Component B and stir for 1 minute. The test data are as follows: Vertex Initial curing time Full curing time Density Hardness (Shore A) Tensile strength Shear strength Expansion ratio Oxygen index IP68 (40 m underwater) Structural fire resistance time (40 mm) Negative pressure high - low temperature vibration test Test standard GB / T 7123.1 - 2015 (Method 3) GB / T 7123.1 - 2015 (Method 4) GB / T 6343 - 2009 GB / T 531.1 - 2008 GB / T 528 - 2009 GB / T 7124 - 2008 GB / T 16807 - 2009 GB / T 2406.2 - 2009 GB / T 4208 - 2008 EN 45545 - 3:2013 GB / T 21563 - 2018 Test data 45 min 109 min 1.35 g / cm³ 89 2.6 mPa 2.7 mPa 20 times 52% Pass Pass in 45 min Pass Before use, mix and stir Component A and Component B. After stirring, it can be directly constructed. The initial curing time is 30 - 50 min. After initial curing, other operations can be carried out and the product will not deform. The complete curing time is 1.5 h - 2 h. This product is suitable for positions with high-strength sealing and high-performance fire protection, such as the wire-passing holes in the underframe of high-speed trains, around the batteries of electric vehicles, and the sealing of electronic components.

Claims

1. A high-strength, low-temperature fire-expanding, sealing and fire-proof adhesive, characterized by: The invention comprises the following raw materials in parts by weight: Component A: 20-30 parts of polyether polyol, 10-20 parts of quartz powder, 1-20 parts of heavy calcium powder, 0.5-2 parts of flame retardant graphite, 20-30 parts of expanded graphite, 10-20 parts of flame retardant, 0.5-2 parts of thixotropic agent, 0.5-1 parts of dehydrating agent, 0.01-0.05 parts of catalyst, 0.01-0.05 parts of delayed catalyst; Component B: 10-20 parts of 4,4-diphenylmethane diisocyanate and 1-5 parts of isophorone diisocyanate.

2. The high-strength, low-temperature, fire-expanding, sealing and fire-proof adhesive according to claim 1, characterized in that: The polyether polyol is a polyether polyol with a hydroxyl value of 330, or a mixture of polyether polyols with a hydroxyl value of 330 and a polyether polyol with a hydroxyl value of 30.

3. The high-strength, low-temperature, fire-expanding, fire-proof adhesive according to claim 1, characterized in that: The quartz powder is 320 mesh fused silica powder or 400 mesh fused silica powder, or a mixture of fused silica powders of different mesh sizes.

4. The high-strength, low-temperature, fire-expanding, fire-proof adhesive according to claim 1, characterized in that: The flame retardant graphite is a particle with a particle size of D50 μm or a particle size of D40 μm, and a purity of more than 95%.

5. The high-strength, low-temperature, fire-expanding, fire-proof adhesive according to claim 1, characterized in that: The expanded graphite has a particle size D of 0.4 mm, an expansion ratio of 40 times, and an initial temperature of 150°C.

6. The high-strength, low-temperature, fire-expanding, fire-proof adhesive according to claim 1, characterized in that: The heavy calcium powder is 200-mesh heavy calcium carbonate powder, or 320-mesh heavy calcium carbonate powder, or a mixture of the two.

7. The high-strength, low-temperature, fire-expanding, fire-proof adhesive according to claim 1, characterized in that: The flame retardant is tert-butylated aryl phosphate or tert-butyl diphenyl phosphate; the thixotropic agent is a modified urea additive, a polyamide rheological additive, or a polyether modified polysiloxane rheological additive; the dewatering agent is an oxopentane dewatering agent or a derivative of oxopentane.

8. The high-strength, low-temperature, fire-expanding, sealing and fire-proof adhesive according to claim 1, characterized in that: The catalyst is an organic bismuth catalyst, wherein the content of metal bismuth is 20±0.5; the delayed catalyst is tert-butylamine and its derivatives, wherein the content of effective substances is greater than 99%.

9. The high-strength, low-temperature, fire-expanding, sealing and fire-proof adhesive according to claim 1, characterized in that: The 4,4-diphenylmethane diisocyanate is a mixture of 4,4-diphenylmethane diisocyanate MDI and its isomers and homologues of multifunctional isocyanates; the isophorone diisocyanate is an alicyclic diisocyanate.

10. A method for preparing a high-strength, low-temperature fire-expanding and fire-proof adhesive as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: Preparation of component A: (1) Dry 10-20 parts of quartz powder, 1-20 parts of heavy calcium powder, 20-30 parts of expanded graphite and 0.5-2 parts of flame retardant graphite in an oven at 120°C for 3-4 days; (2) Pour 20-30 parts of polyether polyol and 10-20 parts of flame retardant by weight into a stirring kettle, heat to 120°C, evacuate to 0.7 MPa and stir for 2-4 hours; (3) Mix 0.5-2 parts by weight of thixotropic agent with the quartz powder and heavy calcium powder treated in step (1), heat to 120°C, evacuate to 0.7 MPa and stir for 2-4 hours; (4) Add the flame retardant graphite and expanded graphite treated in step (1) to the mixture in step (3), then heat to 120°C, evacuate to 0.7 MPa and stir for 1 to 2 hours; (5) When the temperature in the stirring kettle drops to 100°C, add 0.5-1 part of dehydrating agent by weight, evacuate to 0.7 MPa and stir for 1-2 hours; (6) When the temperature in the stirred tank drops to 60°C, add 0.01-0.05 parts of catalyst and 0.01-0.05 parts of delayed catalyst by weight, evacuate to 0.7 MPa and stir for 1-2 hours; Preparation of component B Take 10-20 parts of 4,4-diphenylmethane diisocyanate and 1-5 parts of isophorone diisocyanate by weight, pour them into a separate reaction kettle, evacuate to 0.7 MPa and stir for 1-2 hours.