Explosion-proof polyurea material and preparation method thereof

Abstract

This invention discloses an explosion-proof polyurea material. The raw materials for preparing the polyurea material include component A and component B. Component A consists of chlorine-activated modified aramid fibers with amino and carboxyl groups. This invention significantly improves the tensile properties and tear resistance of the polyurea material. This invention uses a chemical modification method, which differs from modifying aramid fibers and polyurea through physical blending. The polyurea material prepared by this invention has extremely high tear strength. While meeting the requirements for explosion-proof and bulletproof properties, it does not affect the spraying application effect and will not cause nozzle clogging.

Description

Technical Field

[0001] This invention belongs to the field of polyurea production and processing technology, specifically relating to an explosion-proof polyurea material and its preparation method. Background Technology

[0002] Sprayed polyurea materials are widely used in various fields due to their solvent-free and environmentally friendly properties, high mechanical strength, and quick application. These include corrosion protection for submarine pipelines and buried pipelines, storage tanks, concrete protection, waterproofing, military skinning, and chassis protection. For example, polyurea materials can be used for the protection of hazardous chemical vehicle bodies, as their coatings offer high impact resistance and explosion resistance. When the vehicle body catches fire, the coating can seal it, reducing the entry of external oxygen and preventing the spread of combustion. Simultaneously, in the event of an explosion, the coating can absorb and block the blast wave, protecting the lives of drivers and passengers. It can also be used in petrochemical explosion-proof buildings: In the petrochemical industry, sprayed polyurea technology is used in the construction of explosion-proof buildings. This coating can mitigate the blast wave during an explosion, prevent debris from flying, reduce damage to the building, and protect the safety of people and property inside. Furthermore, it can be used for the protection of public places and tunnels: Sprayed polyurea materials are also used for the protection of enclosed spaces such as public places and tunnels. Installing explosion-proof walls, doors, and barriers made of polyurea materials in these locations can effectively prevent the propagation of deflagration shock waves, reducing casualties and property damage. Furthermore, sprayed polyurea materials play a crucial role in ballistic applications; the application of sprayed polyurea technology in ballistic inserts primarily enhances their ballistic protection. Polyurea coatings sprayed onto ceramic or PE surfaces can reduce ceramic breakage and increase protection against multiple projectiles. This coating, combined with repairable explosion-proof ballistic materials, can seamlessly bond ceramic and PE boards together at room temperature, reducing projectile velocity and providing waterproofing, wear resistance, drop crack resistance, aesthetics, and extended service life. In the field of military ballistic and explosion-proof protective materials, in addition to requiring extremely high physical strength, the coating must also exhibit excellent tear resistance under high-speed impact; however, conventional polyurea products often fail to meet these requirements.

[0003] Polyurea formulations are numerous and have a wide range of applications. Depending on the intended use, different formulations and preparation methods should be adopted to suit the specific application. Currently, the conventional solution is to add special fillers to the polyurea resin system or use a pure polyurea system and increase the hard segment content to improve performance. The former, a physical blending method, suffers from poor dispersibility, and the addition of fillers makes polyurea spraying difficult. Furthermore, excessive filler addition can easily cause the filler to separate from the resin under high-speed impact, resulting in a sharp decrease in coating strength. The latter method, while increasing the hard segment content of the resin to increase the material's strength, also significantly increases its hardness, leading to poor low-temperature flexibility and loss of ballistic and explosion-proof properties at low temperatures.

[0004] In addition to possessing the basic characteristics of high-performance fibers, aramid fibers also have advantages such as flame retardancy and fatigue resistance. Since their discovery by DuPont, they have been valued and developed. Due to their excellent performance in impact resistance, fracture elongation, and damage tolerance, aramid fiber-resin composites have good application prospects in the field of composite matrix reinforcement processing.

[0005] Currently, the main challenge in improving the matrix properties of aramid fiber-reinforced composites is the interfacial compatibility between the aramid fibers and the composite material. Aramid fibers are long, straight-chain structures composed of alternating amide bonds and aromatic rings. Due to their highly symmetrical molecular structure, they exhibit high orientation and crystallinity, resulting in a very smooth surface. However, the presence of benzene rings on the molecular chain also introduces significant steric hindrance, leading to a lack of active groups on the aramid fiber surface. For these two reasons, the interfacial adhesion between aramid fibers and the resin matrix is ​​very poor. In practical applications, external factors can easily cause fiber pull-out and detachment, leading to fiber failure. Summary of the Invention

[0006] The purpose of this invention is to provide an explosion-proof polyurea material and its preparation method to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] The raw materials for preparing an explosion-proof polyurea material include component A and component B. The raw material for component A includes chlorine-activated modified aramid fibers with amino and carboxyl groups.

[0009] The preferred structural formula of the modified aramid fiber is:

[0010]

[0011] Preferably, the raw materials for component A also include hexamethylene diisocyanate, catalyst, polyol and polyisocyanate;

[0012] The raw materials for modified aramid fibers include nano-aramid fibers and sodium dichloroisocyanurate.

[0013] Preferably, the preparation steps of component A include:

[0014] (1) Add an appropriate amount of nano-aramid fiber to an appropriate amount of sodium dichloroisocyanurate aqueous solution. After the reaction is complete, add an appropriate amount of hydrochloric acid, heat, purify and dry to obtain modified aramid fiber.

[0015] (2) Mix an appropriate amount of modified aramid fiber, hexamethylene diisocyanate and catalyst. After the reaction is complete, purify and dry to obtain intermediate product 1.

[0016]

[0017] (3) Pre-treat the polyol, then add an appropriate amount of polyisocyanate. After the reaction is complete, add intermediate product 1 to obtain component A.

[0018] Preferably, the mass ratio of nano-aramid fibers to a 50% sodium dichloroisocyanurate aqueous solution is 0.1-1:250-350 parts, and the concentration of the sodium dichloroisocyanurate aqueous solution is 50%.

[0019] The mass ratio of modified aramid fiber, hexamethylene diisocyanate, and catalyst in component A is 1-2:25-35:0-0.1;

[0020] The mass ratio of polyol, polyisocyanate and intermediate product 1 in the raw materials of component A is 50-100:100-250:150-350.

[0021] Preferred,

[0022] The process conditions for step (1) are as follows: nano-aramid fibers are added to sodium dichloroisocyanurate aqueous solution and dispersed and mixed at a high speed of 2000-3000 r / min for 2-8 min. After removing water by filtration, the mixture is reacted in an oven at 50-80℃ for 1-5 hours. After adding hydrochloric acid solution, the mixture is heated at 100-120℃ for 1-2 h. The product is washed with deionized water and finally dried in an oven at 90-110℃ for 6-8 h.

[0023] The process conditions for step (2) are to stir and sonicate in a closed nitrogen environment at room temperature for 8-15 hours. After the reaction is completed, the surface residual HDI is cleaned with hexane to ensure that the solvent on the surface of the nano aramid fiber is cleaned. Finally, it is dried at 50-60℃ for later use.

[0024] The pretreatment process conditions for step (3) are as follows: the polyol is stirred and heated to 95-105℃, dehydrated for 5-7h, the vacuum is released, and the temperature is lowered to below 50℃; the reaction process conditions are as follows: after adding polyisocyanate, the reaction is carried out at 80-100℃ for 3-4h, and then 3-10 parts of intermediate product 1 are added and stirring is continued for 4-6h.

[0025] Preferably, the mass ratio of terminal amino polyether, polyol, coupling agent, chain extender, catalyst, dehydrating agent and pigment is 30-60:20-50:1-2:20-40:0-1:1-5:1-5.

[0026] Preferably, the catalyst includes one or more of bismuth isooctanoate, zinc isooctanoate, triethylenediamine, bismorpholinodiethyl ether, tetrabutyl borate, and tetraisopropyl borate.

[0027] Preferably, the purity of the nano-aramid fiber is ≥99%, and the specific surface area is 7–11 m². 2 / g.

[0028] Preferably, the isocyanate prepolymer of component A has an -NCO content of 14% to 17%; and the isocyanate index of components A and B is 1.05 to 1.10.

[0029] Preferably, the polyisocyanate is one or more of diphenylmethane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, methylcyclohexyl diisocyanate, cyclohexanedimethylene diisocyanate, phenyldimethylene diisocyanate, and 1,4-cyclohexane diisocyanate.

[0030] Preferably, the terminal amino polyether includes one or more of difunctional and trifunctional terminal amino polyethers.

[0031] Preferably, the polyol is one or more of polypropylene glycol, polytetrahydrofuran ether glycol, polycaprolactone glycol, polyester glycol, and polycarbonate glycol, with an average molecular weight of 400-1500, a water content of ≤0.5%, and an acid value of ≤0.8 mg KOH / g.

[0032] Preferably, the coupling agent is one or more of the following: silane coupling agent, borate coupling agent, aluminate coupling agent, borate coupling agent, bimetallic coupling agent, and phosphate coupling agent.

[0033] Preferably, the dehydrating agent is a molecular sieve with a specification of 3a or 4a.

[0034] Preferably, the chain extender includes 3,5-dimethylthiotoluene diamine, 2,4-diamino-3,5-dimethylthiochlorobenzene, 4,4′-bis(sec-butylamino)diphenylmethane, N,N,-dialkylphenyl diamine, 2,4-diamino-3-methylthio-5-propyltoluene, 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 4,4′-bis(sec-butylamino)dicyclohexylmethane, 3,3′-dimethyl-4,4′-bis(sec-butylamino)dicyclohexylmethane, trimethylhexanediamine, or hydrogenated MDA.

[0035] Preferably, the color paste is a common color paste used in the polyurethane industry, and its color includes one of red, yellow, blue, green, white and black pastes, with a water content of ≤0.5%.

[0036] A method for preparing an explosion-proof polyurea material includes the following steps:

[0037] (1) Add an appropriate amount of nano-aramid fiber to an aqueous solution of sodium dichloroisocyanurate. After the reaction is complete, purify and dry the solution, add hydrochloric acid, and heat to obtain modified aramid fiber.

[0038] (2) Mix an appropriate amount of modified aramid fiber, hexamethylene diisocyanate and catalyst. After the reaction is complete, purify and dry to obtain intermediate product 1.

[0039] (3) Pre-treat the polyol, then add an appropriate amount of polyisocyanate, and after the reaction is complete, add intermediate product 1 to obtain component A;

[0040] (4) Mix appropriate amounts of terminal amino polyether, polyol, coupling agent, chain extender, catalyst, dehydrating agent and color paste to obtain component B;

[0041] (5) Mix appropriate amounts of component A and component B to obtain explosion-proof polyurea material.

[0042] Preferably, the volume ratio of component A to component B is 1:1.

[0043] Preferably, the process conditions for step (1) are as follows: nano-aramid fibers are added to sodium dichloroisocyanurate aqueous solution and dispersed and mixed at a high speed of 2000-3000 r / min for 2-8 min. After removing water by filtration, the mixture is reacted in an oven at 50-80℃ for 1-5 hours. After adding hydrochloric acid solution, the mixture is heated at 100-120℃ for 1-2 h. The product is washed with deionized water and finally dried in an oven at 90-110℃ for 6-8 h.

[0044] Preferably, the process conditions for step (2) are: stirring and ultrasonic reaction in a closed nitrogen environment at room temperature for 8-15 hours; after the reaction, the surface residual HDI is cleaned with hexane to ensure that the solvent on the surface of the aramid fiber is cleaned; and finally, it is dried at 50-60°C for later use.

[0045] Preferably, the pretreatment process conditions in step (3) are: stirring and heating the polyol to 95-105°C, dehydrating for 5-7 hours, removing the vacuum, and cooling to below 50°C; the reaction process conditions are: adding the polyisocyanate and reacting at 80-100°C for 3-4 hours, then adding intermediate product 1 and continuing to stir for 4-6 hours.

[0046] Preferably, the process conditions for step (4) are to stir, grind and filter the raw materials of component B.

[0047] Compared with the prior art, the beneficial effects of the present invention are:

[0048] This invention significantly improves the tensile properties and tear resistance of polyurea materials. The invention employs a chemical modification method, which differs from modifying aramid fibers and polyurea through physical blending. The polyurea material prepared by this invention has extremely high tear strength, and while meeting the requirements for explosion-proof and bulletproof properties, it does not affect the spraying application effect and does not cause spray gun clogging. Detailed Implementation

[0049] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0050] Example 1:

[0051] (1) 0.1 parts of nano aramid fiber were added to 250 parts of sodium dichloroisocyanurate aqueous solution with a concentration of 50%, and dispersed and mixed at a high speed of 2000 r / min for 2 min. After removing water by filtration, the mixture was reacted in an oven at 50℃ for 1 hour. After adding hydrochloric acid solution, the mixture was heated at 100℃ for 1 hour. The product was washed with deionized water and finally dried in an oven at 90℃ for 6 hours to obtain modified aramid fiber.

[0052] (2) Mix 1 part of modified aramid fiber and 25 parts of hexamethylene diisocyanate, stir and sonicate in a closed nitrogen environment at room temperature for 8 hours. After the reaction, clean the surface of residual HDI with hexane to ensure that the solvent on the surface of the aramid fiber is clean. Finally, dry at 50°C for later use to obtain intermediate product 1.

[0053] (3) Stir and heat 50 parts of polyoxypropylene glycol to 95°C, dehydrate for 5 hours, remove the vacuum, cool down to below 50°C, then add 150 parts of diphenylmethane diisocyanate and react at 80°C for 3 hours. Add 3 parts of intermediate product 1 and continue stirring for 4 hours to obtain component A.

[0054] (4) 30 parts of difunctional amino-terminated polyether, 20 parts of polyoxypropylene glycol, 1 part of silane coupling agent, 20 parts of 3,5-dimethylthiotoluene diamine, 1 part of molecular sieve of specification 3a and 1 part of color paste are stirred, ground and filtered to obtain component B.

[0055] (5) Mix component A and component B at a volume ratio of 1:1 to obtain explosion-proof polyurea material.

[0056] Example 2:

[0057] (1) Add 1 part of nano aramid fiber to 350 parts of 50% sodium dichloroisocyanurate aqueous solution, and disperse and mix at a high speed of 3000 r / min for 8 min. After removing water by filtration, react in an oven at 80℃ for 5 hours. After adding hydrochloric acid solution, heat at 120℃ for 2 hours. Wash the product with deionized water and finally dry in an oven at 110℃ for 8 hours to obtain modified aramid fiber.

[0058] (2) Mix 2 parts of modified aramid fiber, 35 parts of hexamethylene diisocyanate, 0.1 parts of zinc isooctanoate, 0.03 parts of triethylenediamine, and 0.01 parts of bismorpholino diethyl ether. Stir and sonicate in a closed nitrogen environment at room temperature for 15 hours. After the reaction, clean the surface of residual HDI with hexane to ensure that the solvent on the surface of the aramid fiber is clean. Finally, dry at 60°C for later use to obtain intermediate product 1.

[0059] (3) Stir and heat 100 parts of polytetrahydrofuran ether diol to 105°C, dehydrate for 7 hours, remove the vacuum, cool down to below 50°C, then add 250 parts of methylcyclohexyl diisocyanate and react at 100°C for 4 hours. Add 10 parts of intermediate product 2 and continue stirring for 6 hours to obtain component A.

[0060] (4) 60 parts of trifunctional amino-terminated polyether, 50 parts of polyester glycol, 2 parts of coupling agent phosphate coupling agent, 40 parts of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 1 part of tetrabutyl borate, 5 parts of molecular sieve of specification 4a and 5 parts of color paste are stirred, ground and filtered to obtain component B.

[0061] (5) Mix component A and component B at a volume ratio of 1:1 to obtain explosion-proof polyurea material.

[0062] Example 3:

[0063] (1) 0.5 parts of nano aramid fiber were added to 200 parts of 50% sodium dichloroisocyanurate aqueous solution and dispersed and mixed at a high speed of 2500 r / min for 6 min. After removing water by filtration, the mixture was reacted in an oven at 60℃ for 3 hours. After adding hydrochloric acid solution, the mixture was heated at 110℃ for 1.5 h. The product was washed with deionized water and finally dried in an oven at 100℃ for 7 h to obtain modified aramid fiber.

[0064] (2) Mix 1.5 parts of modified aramid fiber, 30 parts of hexamethylene diisocyanate and 0.04 parts of tetraisopropyl borate, stir and sonicate in a closed nitrogen environment at room temperature for 10 h. After the reaction, clean the surface of residual HDI with hexane to ensure that the solvent on the surface of the aramid fiber is clean. Finally, dry at 55°C for later use to obtain intermediate product 1.

[0065] (3) Stir and heat 60 parts of polycaprolactone diol to 100°C, dehydrate for 6 hours, remove the vacuum, cool down to below 50°C, then add 200 parts of phthalimide diisocyanate and react at 90°C for 3.5 hours, add 6 parts of intermediate product 1 and continue stirring for 5 hours to obtain component A.

[0066] (4) 20 parts of difunctional amino-terminated polyether, 30 parts of trifunctional amino-terminated polyether, 30 parts of polyoxypropylene glycol, 10 parts of polycaprolactone glycol, 1.5 parts of borate coupling agent, 30 parts of 2,4-diamino-3-methylthio-5-propyltoluene, 0.6 parts of triethylenediamine catalyst, 2 parts of molecular sieve of specification 4a and 2 parts of color paste are stirred, ground and filtered to obtain component B;

[0067] (5) Mix component A and component B at a volume ratio of 1:1 to obtain explosion-proof polyurea material.

[0068] Comparative Example 1:

[0069] (1) 0.5 parts of nano aramid fiber were added to 200 parts of 50% hypochlorous acid aqueous solution and dispersed and mixed at a high speed of 2500 r / min for 6 min. After removing water by filtration, the mixture was reacted in an oven at 60℃ for 3 hours. After adding hydrochloric acid solution, the mixture was heated at 110℃ for 1.5 h. The product was washed with deionized water and finally dried in an oven at 100℃ for 7 h to obtain modified aramid fiber.

[0070] (2) Mix 1.5 parts of modified aramid fiber, 30 parts of hexamethylene diisocyanate and 0.04 parts of tetraisopropyl borate, stir and sonicate in a closed nitrogen environment at room temperature for 10 h. After the reaction, clean the surface of residual HDI with hexane to ensure that the solvent on the surface of the aramid fiber is clean. Finally, dry at 55°C for later use to obtain intermediate product 1.

[0071] (3) Stir and heat 60 parts of polycaprolactone diol to 100°C, dehydrate for 6 hours, remove the vacuum, cool down to below 50°C, then add 200 parts of polyisocyanate phthalimide diisocyanate and react at 90°C for 3.5 hours, add 6 parts of intermediate product 1 and continue stirring for 5 hours to obtain component A.

[0072] (4) 20 parts of difunctional amino-terminated polyether, 30 parts of trifunctional amino-terminated polyether, 30 parts of polyoxypropylene glycol, 10 parts of polycaprolactone glycol, 1.5 parts of borate coupling agent, 30 parts of 2,4-diamino-3-methylthio-5-propyltoluene, 0.6 parts of triethylenediamine catalyst, 2 parts of molecular sieve of specification 4a and 2 parts of color paste are stirred, ground and filtered to obtain component B;

[0073] (5) Mix component A and component B at a volume ratio of 1:1 to obtain explosion-proof polyurea material.

[0074] Comparative Example 2:

[0075] (1) 0.5 parts of nano aramid fiber were added to 200 parts of 50% sodium dichloroisocyanurate aqueous solution and dispersed and mixed at a high speed of 2500 r / min for 6 min. After removing water by filtration, the mixture was reacted in an oven at 60℃ for 3 hours. After adding hydrochloric acid solution, the mixture was heated at 110℃ for 1.5 h. The product was washed with deionized water and finally dried in an oven at 100℃ for 7 h to obtain modified aramid fiber.

[0076] (2) Mix 1.5 parts of modified aramid fiber, 30 parts of diphenylmethane-4,4'-diisocyanate and 0.04 parts of tetraisopropyl borate, and stir and sonicate in a closed nitrogen environment at room temperature for 10 h. After the reaction, clean the surface of residual HDI with hexane to ensure that the solvent on the surface of the aramid fiber is clean. Finally, dry at 55°C for later use to obtain intermediate product 1.

[0077] (3) Stir and heat 60 parts of polycaprolactone diol to 100°C, dehydrate for 6 hours, remove the vacuum, cool down to below 50°C, then add 200 parts of polyisocyanate phthalimide diisocyanate and react at 90°C for 3.5 hours, add 6 parts of intermediate product 1 and continue stirring for 5 hours to obtain component A.

[0078] (4) 20 parts of difunctional amino-terminated polyether and 30 parts of trifunctional amino-terminated polyether), 30 parts of polyoxypropylene glycol, 10 parts of polycaprolactone glycol, 1.5 parts of borate coupling agent, 30 parts of 2,4-diamino-3-methylthio-5-propyltoluene (TX-3), 0.6 parts of triethylenediamine, 2 parts of molecular sieve of specification 4a and 2 parts of color paste are stirred, ground and filtered to obtain component B;

[0079] (5) Mix component A and component B at a volume ratio of 1:1 to obtain explosion-proof polyurea material.

[0080] Comparative Example 3:

[0081] (1) Mix 1.5 parts of nano aramid fiber, 30 parts of hexamethylene diisocyanate and 0.04 parts of tetraisopropyl borate, stir and sonicate in a closed nitrogen environment at room temperature for 10 h. After the reaction, clean the surface of residual HDI with hexane to ensure that the solvent on the surface of the aramid fiber is clean. Finally, dry at 55°C for later use to obtain the intermediate product.

[0082] (2) Stir and heat 60 parts of polycaprolactone diol to 100°C, dehydrate for 6 hours, remove the vacuum, cool down to below 50°C, then add 200 parts of phthalimide diisocyanate and react at 90°C for 3.5 hours. Add 6 parts of intermediate product and continue stirring for 5 hours to obtain component A.

[0083] (3) 20 parts of difunctional amino-terminated polyether, 30 parts of trifunctional amino-terminated polyether, 30 parts of polyoxypropylene glycol, 10 parts of polycaprolactone glycol, 1.5 parts of borate coupling agent, 30 parts of 2,4-diamino-3-methylthio-5-propyltoluene, 0.6 parts of triethylenediamine catalyst, 2 parts of molecular sieve of specification 4a and 2 parts of color paste are stirred, ground and filtered to obtain component B;

[0084] (4) Mix component A and component B at a volume ratio of 1:1 to obtain explosion-proof polyurea material.

[0085] The components A and B prepared in Examples 1-3 and Comparative Examples 1-3 were mixed evenly using a spraying machine and sprayed onto the surface of a steel plate. The spraying pressure was 10 MPa, the spraying temperature was 65°C, and the coating was placed in an environment with a temperature of (25±2)°C and a humidity of (50±5)% for 7 days. After curing, performance tests were conducted, and the results are shown in Table 1.

[0086] Table 1 Test Results

[0087]

[0088] A comparison of Examples 1-3 and Comparative Example 1 shows that the tensile strength of Examples 1-3 is about 50% higher than that of Comparative Example 1, the elongation at break is about 10% higher than that of Comparative Example 1, and the tear strength is about 30% higher than that of Comparative Example 1. This indicates that the use of sodium dichloroisocyanurate in the modified aramid fiber in this invention has a significant impact on the tensile strength, elongation at break, and tear strength of the polyurea material. Furthermore, the fact that Comparative Example 1 experienced spray gun clogging also indicates that sodium dichloroisocyanurate affects the spraying application of the polyurea material in this application.

[0089] As can be seen from the comparison between Examples 1-3 and Comparative Example 2, the tensile strength of Examples 1-3 is about 80% higher than that of Comparative Example 2, the elongation at break is about 7% higher, and the tear strength is about twice as high. However, the spraying effect is basically the same as that of Examples 1-3.

[0090] A comparison of Examples 1-3 and Comparative Example 3 shows that the tensile strength of Examples 1-3 is approximately twice that of Comparative Example 3, the tear strength is approximately twice that of Comparative Example 3, and the elongation at break is approximately 5% higher than that of Comparative Example 3. Furthermore, Comparative Example 3 exhibits spray gun clogging. This indicates that the chemical modification of aramid fiber and the preparation of intermediate product 1 during the polyurea preparation process significantly impacts the tensile and tear strength of the polyurea material of this invention, and also affects the spraying application effect.

[0091] Although embodiments of the invention have been shown and described (see the detailed description above), it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An explosion-proof polyurea material, characterized in that, The raw materials for preparing the polyurea material include component A and component B, and the raw material for component A includes modified aramid fiber. Component A is prepared using the following steps: (1) Add an appropriate amount of nano-aramid fiber to an appropriate amount of sodium dichloroisocyanurate aqueous solution. After the reaction is complete, add an appropriate amount of hydrochloric acid, heat, purify and dry to obtain the modified aramid fiber. (2) Mix an appropriate amount of modified aramid fiber, hexamethylene diisocyanate and catalyst. After the reaction is complete, purify and dry to obtain intermediate product 1. The structural formula of intermediate product 1 is: ； (3) Pre-treat the polyol, then add an appropriate amount of polyisocyanate. After the reaction is complete, add an appropriate amount of intermediate product 1 to obtain component A.

2. The explosion-proof polyurea material according to claim 1, wherein the modified aramid fiber has the following structural formula: 。 3. The explosion-proof polyurea material according to claim 1, characterized in that, The mass ratio of the nano-aramid fiber to the sodium dichloroisocyanurate aqueous solution is 0.1-1:250-350 parts, and the concentration of the sodium dichloroisocyanurate aqueous solution is 50%. The mass ratio of the modified aramid fiber, hexamethylene diisocyanate, and catalyst is 1-2:25-35:0-0.1; The mass ratio of the polyol, polyisocyanate and intermediate 1 is 50-100:150-250:200-350.

4. The explosion-proof polyurea material of claim 1, wherein: The process conditions for step (1) are as follows: nano-aramid fibers are added to sodium dichloroisocyanurate aqueous solution and dispersed and mixed at a high speed of 2000-3000 r / min for 2-8 min. After removing water by filtration, the mixture is reacted in an oven at 50-80℃ for 1-5 hours. After adding hydrochloric acid solution, the mixture is heated at 100-120℃ for 1-2 h. The product is washed with deionized water and finally dried in an oven at 90-110℃ for 6-8 h. The process conditions for step (2) are: stirring and ultrasonic reaction in a closed nitrogen environment at room temperature for 8-15 h; after the reaction, the surface residual HDI is cleaned with hexane to ensure that the solvent on the surface of the nano aramid fiber is cleaned; and finally, it is dried at 50-60°C for later use. The pretreatment process conditions for step (3) are as follows: the polyol is stirred and heated to 95-105℃, dehydrated for 5-7h, the vacuum is released, and the temperature is lowered to below 50℃; the reaction process conditions are as follows: after adding polyisocyanate, the reaction is carried out at 80-100℃ for 3-4h, and then intermediate product 1 is added and stirring is continued for 4-6h.

5. The explosion-proof polyurea material according to claim 1, characterized in that: The purity of the nanofibril is > 99%, the specific surface area is 7 - 11 m 2 / g.

6. The explosion-proof polyurea material of claim 1, wherein: The content of -NCO in component A is 14% to 17%; the isocyanate index of component A and component B is 1.05 to 1.

10.

7. The explosion-proof polyurea material according to claim 1, characterized in that: The polyisocyanate is one or more of diphenylmethane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, methylcyclohexyl diisocyanate, cyclohexanedimethylene diisocyanate, phenyldimethylene diisocyanate, and 1,4-cyclohexane diisocyanate. The catalyst includes one or more of bismuth isooctanoate, zinc isooctanoate, triethylenediamine, bismorpholino diethyl ether, tetrabutyl borate, and tetraisopropyl borate. The raw materials of component B include: amino-terminated polyether, polyol, coupling agent, chain extender, catalyst, dehydrating agent and color paste; The terminal amino polyether includes one or more of difunctional and trifunctional terminal amino polyethers. The polyol is one or more of polypropylene glycol, polytetrahydrofuran ether glycol, polycaprolactone glycol, polyester glycol, and polycarbonate glycol. The average molecular weight of the polyol is 400-1500, the water content is ≤0.5%, and the acid value is ≤0.8mg KOH / g. The coupling agent is one or more of the following: silane coupling agent, borate coupling agent, aluminate coupling agent, borate coupling agent, bimetallic coupling agent, and phosphate coupling agent. The dehydrating agent is a molecular sieve, and the molecular sieve has a specification of 3a or 4a. The chain extender includes 3,5-dimethylthiotoluene diamine (E-300), 2,4-diamino-3,5-dimethylthiochlorobenzene (TX-2), 4,4′-bis(sec-butylamino)diphenylmethane (Unilink4200), N,N,-dialkylphenyl diamine, 2,4-diamino-3-methylthio-5-propyltoluene (TX-3), 3,3'-dimethyl-4,4′-diaminodicyclohexylmethane, 4,4'-bis(sec-butylamino)dicyclohexylmethane, 3,3'-dimethyl-4,4'-bis(sec-butylamino)dicyclohexylmethane, trimethylhexanediamine, or hydrogenated MDA; The mass ratio of the terminal amino polyether, polyol, coupling agent, chain extender, catalyst, dehydrating agent and pigment is 30-60:20-50:1-2:20-40:0-1:1-5:1-5.

8. A method of preparing an explosion-proof polyurea material, characterized by The preparation method includes the following steps: (1) Add an appropriate amount of nano-aramid fiber to an appropriate amount of sodium dichloroisocyanurate aqueous solution. After the reaction is complete, add hydrochloric acid, heat, purify and dry to obtain modified aramid fiber. (2) Mix an appropriate amount of modified aramid fiber, hexamethylene diisocyanate and catalyst. After the reaction is complete, purify and dry to obtain intermediate product 1. (3) Pre-treat the polyol, then add an appropriate amount of polyisocyanate, and after the reaction is complete, add an appropriate amount of intermediate product 1 to obtain component A; (4) Mix appropriate amounts of terminal amino polyether, polyol, coupling agent, chain extender, catalyst, dehydrating agent and color paste to obtain component B; (5) Mix component A and component B to obtain explosion-proof polyurea material.

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