Polyurethane modified composite coating with bulletproof and explosion-proof functions and preparation method thereof

Abstract

The application discloses a polyurethane modified composite coating with bulletproof and explosion-proof functions and a preparation method thereof, and relates to the technical field of coatings. A polyurethane prepolymer is obtained by chemically reacting a diisocyanate containing a benzene ring with a polyester polyol; a polyurea prepolymer is obtained by chemically reacting the diisocyanate containing the benzene ring with a diamine; the polyurethane prepolymer and the polyurea prepolymer are chemically reacted to obtain a polyurethane-polyurea composite polymer; finally, the polyurethane-polyurea composite polymer, an ultrahigh molecular weight polyethylene fiber, a polyurethane-modified silicon carbide whisker shear thickening liquid and an additive are compounded to obtain the polyurethane modified composite coating with the bulletproof and explosion-proof functions. The polyurethane modified composite coating has excellent bulletproof and explosion-proof functions and has a wide and extremely potential application prospect.

Description

Technical Field

[0001] This application relates to the field of coating technology, and in particular to a polyurethane modified composite coating with bulletproof and explosion-proof functions and its preparation method. Background Technology

[0002] With the rapid development of modern industrial technology, the demand for bulletproof and explosion-proof materials in military equipment, public safety facilities, and transportation vehicles is increasing. Traditional bulletproof and explosion-proof materials mostly use metal alloys, ceramics, or single polymer materials. Although they have certain protective properties, they suffer from drawbacks such as heavy weight, poor flexibility, and insufficient resistance to repeated impacts. Furthermore, single material systems are insufficient to meet current explosion-proof and bulletproof requirements, necessitating breakthroughs in performance through material composites and structural optimization.

[0003] For example, Chinese patent application CN116218338A discloses a bulletproof and explosion-proof coating and its preparation method. This bulletproof and explosion-proof coating comprises: 40-50 parts by weight of polyurea resin, 1-3 parts by weight of dispersing agent, 1-2 parts by weight of anti-settling agent; 20-35 parts by weight of bulletproof filler; 1-3 parts by weight of defoamer; 10-20 parts by weight of coloring pigment; and 20-30 parts by weight of modified curing agent; wherein the molecular weight of the polyurea resin is adjusted to 30,000-50,000. However, the bulletproof and explosion-proof coating prepared by this technical solution simply uses physical means to composite a single reinforcing phase with the matrix, and lacks a multi-scale synergistic reinforcement mechanism; therefore, its bulletproof and explosion-proof performance still has considerable room for improvement. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this application provides a polyurethane-modified composite coating with bulletproof and explosion-proof functions and its preparation method. A polyurethane prepolymer is obtained by chemically reacting a benzene-ring-containing diisocyanate with a polyester polyol; a polyurea prepolymer is obtained by chemically reacting a benzene-ring-containing diisocyanate with a diamine; the polyurethane prepolymer is then chemically reacted with the polyurea prepolymer to obtain a polyurethane-polyurea composite polymer; finally, the polyurethane-polyurea composite polymer, ultra-high molecular weight polyethylene fiber, polyurethane-modified silicon carbide whisker shearing thickening liquid, and additives are combined to obtain a polyurethane-modified composite coating with bulletproof and explosion-proof functions.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] In a first aspect, this application provides a polyurethane-modified composite coating with bulletproof and explosion-proof functions, comprising a polyurethane-polyurea composite polymer, ultra-high molecular weight polyethylene fiber, a polyurethane-modified silicon carbide whisker shearing thickening liquid, and additives; the polyurethane-polyurea composite polymer is obtained by chemically reacting a polyurethane prepolymer with a polyurea prepolymer; the polyurethane prepolymer is obtained by chemically reacting a benzene-ring-containing diisocyanate with a polyester polyol; and the polyurea prepolymer is obtained by chemically reacting a benzene-ring-containing diisocyanate with a diamine.

[0007] Secondly, this application provides a method for preparing a polyurethane modified composite coating with bulletproof and explosion-proof functions, comprising the following steps:

[0008] Add silicon carbide whiskers to a stirrer, and under nitrogen protection, add isocyanate-based silane coupling agent dropwise to the stirrer while stirring.

[0009] After the isocyanate-based silane coupling agent is added, continue stirring for 5-10 minutes, and then dry it at 80-100℃ for 2-4 hours under nitrogen protection to obtain modified silicon carbide whiskers, which are then sealed for later use.

[0010] Polyurethane was added to xylene and stirred and dissolved at 50-60°C to obtain a mixture. Then, modified silicon carbide whiskers that were sealed and ready for use were added and stirred for 10-30 minutes to obtain a polyurethane-modified silicon carbide whisker shear thickening solution.

[0011] DMF, benzene ring-containing diisocyanate, polyester polyol and organotin catalyst are added to a reactor and stirred at 60-90°C for 1-3 hours under nitrogen protection to obtain polyurethane prepolymer.

[0012] DMF, benzene ring-containing diisocyanate and diamine are added to a reaction vessel and stirred at 40-60°C for 20-40 min under nitrogen protection to obtain polyurea prepolymer;

[0013] Polyurethane prepolymer, polyurea prepolymer and organotin catalyst are added to a reactor and stirred at 50-80°C for 5-8 hours under nitrogen protection to obtain polyurethane-polyurea composite polymer.

[0014] Ultra-high molecular weight polyethylene fiber, polyurethane-modified silicon carbide whisker shearing thickener, dispersant, flame retardant and toughening agent are added to polyurethane-polyurea composite polymer. Stirred at 45-60℃ for 30-60 minutes under nitrogen protection. Then leveling agent and stabilizer are added in sequence, and finally defoamer is added. Stirring is continued for 10-20 minutes to obtain polyurethane modified composite coating with bulletproof and explosion-proof functions.

[0015] Beneficial technical effects:

[0016] In the polyurethane-modified composite coating with bulletproof and explosion-proof functions prepared in this application, the polyurethane prepolymer and the polyurea prepolymer obtained from the reaction are further reacted through a chemical reaction between isocyanate groups and hydroxyl groups to obtain a polyurethane-polyurea composite polymer whose molecular chain contains both rigid networks of rigid groups such as benzene rings and urea groups, and flexible carbon chains derived from polyester polyols and long-chain diamines. Using this polyurethane-polyurea composite polymer as the matrix of the composite coating gives the composite coating excellent mechanical properties. Thus, when subjected to bullet or explosion impacts, it can absorb energy through deformation and resist penetration and crack propagation through the rigid network, thereby having excellent bulletproof and explosion-proof functions. Furthermore, the polyurethane-modified silicon carbide whisker shear thickening liquid enables the prepared composite coating to rapidly trigger a shear thickening effect when subjected to high-speed impacts, and to quickly harden to resist penetration. Furthermore, in the polyurethane-modified silicon carbide whisker shear thickening liquid, the isocyanate-based silane coupling agent-modified silicon carbide whiskers contain a large number of isocyanate groups. On the one hand, this can improve the interfacial compatibility between inorganic whiskers and the organic matrix; on the other hand, it can further react with the amino or hydroxyl groups in the polyurethane-polyurea composite polymer to form strong chemical bonds. In addition, the polyurethane component, due to the principle of like compatibility, also promotes the compatibility between inorganic whiskers and the organic matrix. Therefore, it can reduce stress concentration in the composite coating and prevent interfacial debonding of the components. In summary, the polyurethane-modified silicon carbide whisker shear thickening liquid and the polyurethane-polyurea composite polymer matrix work synergistically to further enhance the bulletproof and explosion-proof functions of the prepared composite coating. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the preparation process of polyurethane modified composite coatings with bulletproof and explosion-proof functions.

[0018] Figure 2 This is a schematic diagram of the chemical reactions that occur during the preparation of the composite coating. Detailed Implementation

[0019] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the application will be further described in detail below with reference to embodiments. However, this should not be construed as limiting the scope of this application to the following examples. All other embodiments obtained by those skilled in the art without creative effort without departing from the above-described methodological spirit of this application are within the scope of protection of this application.

[0020] In this application, the terminology used is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0021] The singular forms “for,” “a,” “any one,” “any item,” and “the” used in this application are intended to include the plural forms unless the context clearly indicates otherwise.

[0022] Furthermore, the terms "first" and "second" appearing in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In a first aspect, this application provides a polyurethane-modified composite coating with bulletproof and explosion-proof functions, comprising a polyurethane-polyurea composite polymer, ultra-high molecular weight polyethylene fiber, a polyurethane-modified silicon carbide whisker shear thickening liquid, and additives; the polyurethane-polyurea composite polymer is obtained by chemically reacting a polyurethane prepolymer with a polyurea prepolymer; the polyurethane prepolymer is obtained by chemically reacting a benzene-ring-containing diisocyanate with a polyester polyol; the polyurea prepolymer is obtained by chemically reacting a benzene-ring-containing diisocyanate with a diamine; the additives include dispersants, leveling agents, defoamers, stabilizers, flame retardants, and toughening agents.

[0024] In one feasible implementation, the polyurethane-modified silicon carbide whisker shear thickening liquid contains silicon carbide whiskers modified with isocyanate-based silane coupling agents; the mass ratio of the silicon carbide whiskers to the isocyanate-based silane coupling agents is (95-99):(1-5).

[0025] In one feasible implementation, the isocyanate-based silane coupling agent comprises any one of 3-isocyanate-propyltrimethoxysilane, 3-isocyanate-propyltriethoxysilane, and tris(3-trimethoxysilylpropyl)isocyanurate.

[0026] In one feasible implementation, the mass ratio of the polyurethane-polyurea composite polymer, ultra-high molecular weight polyethylene fiber, polyurethane-modified silicon carbide whisker shear thickener, dispersant, leveling agent, defoamer, stabilizer, flame retardant and toughening agent is (40-60): (8-15): (15-25): (1-3): (1-2): (1-2): (1-2): (5-8): (3-5).

[0027] In one feasible implementation, the dispersant comprises any one of sodium polyacrylate, sodium polymethacrylate, sodium tripolyphosphate, sodium hexametaphosphate, oleic acid, stearic acid, alkylphenol polyoxyethylene ether phosphate, glyceryl monostearate, BYK-111, and BYK-190.

[0028] In one feasible implementation, the leveling agent comprises any one of polydimethylsiloxane, polyether-modified polydimethylsiloxane, and acrylate-ethyl acrylate copolymer.

[0029] In one feasible implementation, the defoamer includes any one of dimethyl silicone oil, polyoxyethylene glycerol ether, and polyoxypropylene glycerol ether.

[0030] In one feasible implementation, the stabilizer comprises any one of barium stearate, calcium stearate, zinc stearate, 2,6-di-tert-butyl-p-cresol, phenyl p-hydroxybenzoate, dilauryl thiodipropionate, and triphenyl phosphite.

[0031] In one feasible implementation, the flame retardant includes any one of aluminum hydroxide, magnesium hydroxide, triethyl phosphate, diphenyl phosphate, tricresyl phosphate, decabromodiphenyl ether, and tetrabromobisphenol A.

[0032] In one feasible implementation, the toughening agent includes any one of nitrile rubber, ethylene propylene rubber, chloroprene rubber, styrene-butadiene rubber, SBS, SIS, and TPU.

[0033] In one feasible implementation, the benzene ring-containing diisocyanate includes any one of isophthalimide diisocyanate, tetramethyl isophthalimide diisocyanate, and diphenylmethane diisocyanate.

[0034] In one feasible implementation, the diamine includes any one of heptanediamine, decanedanediamine, 1,12-diaminododecane, and 1,14-tetradecanediamine.

[0035] Secondly, this application provides a method for preparing a polyurethane-modified composite coating with bulletproof and explosion-proof functions, such as... Figure 1 As shown, it includes the following steps:

[0036] Add silicon carbide whiskers to a stirrer, and under nitrogen protection, add isocyanate-based silane coupling agent dropwise to the stirrer while stirring.

[0037] After the isocyanate-based silane coupling agent is added, continue stirring for 5-10 minutes, and then dry it at 80°C for 2-4 hours under nitrogen protection to obtain modified silicon carbide whiskers, which are then sealed for later use.

[0038] Polyurethane was added to xylene and stirred and dissolved at 50-60°C to obtain a mixture. Then, modified silicon carbide whiskers that were sealed and ready for use were added and stirred for 10-30 minutes to obtain a polyurethane-modified silicon carbide whisker shear thickening solution.

[0039] DMF, benzene ring-containing diisocyanate, polyester polyol and organotin catalyst are added to a reactor and stirred at 60-90°C for 1-3 hours under nitrogen protection to obtain polyurethane prepolymer.

[0040] DMF, benzene ring-containing diisocyanate and diamine are added to a reaction vessel and stirred at 40-60°C for 20-40 min under nitrogen protection to obtain polyurea prepolymer;

[0041] Polyurethane prepolymer, polyurea prepolymer and organotin catalyst are added to a reactor and stirred at 50-80°C for 5-8 hours under nitrogen protection to obtain polyurethane-polyurea composite polymer.

[0042] Ultra-high molecular weight polyethylene fiber, polyurethane-modified silicon carbide whisker shearing thickener, dispersant, flame retardant and toughening agent are added to polyurethane-polyurea composite polymer. Stirred at 45-60℃ for 30-60 minutes under nitrogen protection. Then leveling agent and stabilizer are added in sequence, and finally defoamer is added. Stirring is continued for 10-20 minutes to obtain polyurethane modified composite coating with bulletproof and explosion-proof functions.

[0043] In one feasible implementation, during the preparation of the polyurethane-modified silicon carbide whisker shear thickening liquid, the mass ratio of xylene, polyurethane and modified silicon carbide whiskers is (30-50):(25-40):(15-30).

[0044] In one feasible implementation, during the preparation of the polyurethane prepolymer, the mass ratio of the DMF, the benzene ring-containing diisocyanate, the polyester polyol, and the organotin catalyst is (40-60):(10-20):(30-40):(0.1-0.5).

[0045] In one feasible implementation, during the preparation of the polyurea prepolymer, the mass ratio of DMF, benzene ring-containing diisocyanate to diamine is (50-70):(20-40):(5-10).

[0046] In one feasible implementation, during the preparation of the polyurethane-polyurea composite polymer, the mass ratio of the polyurethane prepolymer, the polyurea prepolymer, and the organotin catalyst is (62-74):(25-42):(0.1-0.5).

[0047] The following will describe in detail, with reference to different embodiments, a polyurethane modified composite coating with bulletproof and explosion-proof functions and its preparation method provided in this application.

[0048] Example 1:

[0049] like Figure 1 As shown, a method for preparing a polyurethane modified composite coating with bulletproof and explosion-proof functions includes the following steps:

[0050] 1. Add 97g of silicon carbide whiskers to a stirrer, and under nitrogen protection, add 3g of 3-isocyanate-propyltrimethoxysilane dropwise to the stirrer while stirring.

[0051] After adding 2,3-isocyanate-propyltrimethoxysilane, continue stirring for 8 minutes to obtain modified silicon carbide whiskers. Dry them at 80°C for 3 hours under nitrogen protection and seal them for later use.

[0052] 3. Add 35g of polyurethane to 40g of xylene, stir and dissolve at 55℃, then add 25g of sealed modified silicon carbide whiskers, stir for 20min to obtain polyurethane-modified silicon carbide whisker shear thickening liquid.

[0053] 4. Add 50g DMF, 15g isophthalimide diisocyanate, 34.8g polyester polyol and 0.2g organotin catalyst to the reactor, stir and react at 75℃ for 2h under nitrogen protection to obtain polyurethane prepolymer dispersion.

[0054] 5. Add 60g DMF, 30g m-phthalimide diisocyanate and 10g heptanediamine to the reactor, stir and react at 50°C for 30min under nitrogen protection to obtain polyurea prepolymer dispersion;

[0055] 6. Add 70g of polyurethane prepolymer dispersion, 29.8g of polyurea prepolymer dispersion, and 0.2g of organotin catalyst to a reactor, and stir at 65°C for 6 hours under nitrogen protection to obtain a polyurethane-polyurea composite polymer; the reaction diagrams of steps 4 to 6 are shown below. Figure 2 As shown;

[0056] 7. Add 10g of ultra-high molecular weight polyethylene fiber, 24g of polyurethane-modified silicon carbide whisker shearing thickener, 2g of sodium polymethacrylate, 6g of triethyl phosphate and 4g of ethylene propylene rubber to 50g of polyurethane-polyurea composite polymer. Stir at 50℃ for 45min under nitrogen protection. Then add 1.5g of polyether-modified polydimethylsiloxane and 1.5g of zinc stearate in sequence. Finally, add 1g of polyoxyethylene glycerol ether and continue stirring for 12min to obtain a polyurethane-modified composite coating with bulletproof and explosion-proof functions.

[0057] Example 2:

[0058] like Figure 1 As shown, a method for preparing a polyurethane modified composite coating with bulletproof and explosion-proof functions includes the following steps:

[0059] 1. Add 95g of silicon carbide whiskers to a stirrer, and under nitrogen protection, add 5g of tris(3-trimethoxysilylpropyl)isocyanurate dropwise to the stirrer while stirring.

[0060] 2. After adding tris(3-trimethoxysilylpropyl)isocyanurate, continue stirring for 7 minutes to obtain modified silicon carbide whiskers. Dry them at 90°C for 4 hours under nitrogen protection and seal them for later use.

[0061] 3. Add 40g of polyurethane to 35g of xylene, stir and dissolve at 60℃, then add 25g of sealed modified silicon carbide whiskers, stir for 30min to obtain polyurethane-modified silicon carbide whisker shear thickening liquid.

[0062] 4. Add 45g DMF, 18g diphenylmethane diisocyanate, 36.7g polyester polyol and 0.3g organotin catalyst to the reactor, stir and react at 90℃ for 1h under nitrogen protection to obtain polyurethane prepolymer dispersion.

[0063] 5. Add 55g DMF, 35g diphenylmethane diisocyanate and 10g decanediamine to the reactor, stir and react at 60℃ for 20min under nitrogen protection to obtain polyurea prepolymer dispersion;

[0064] 6. Add 65g of polyurethane prepolymer dispersion, 34.7g of polyurea prepolymer dispersion and 0.3g of organotin catalyst to a reactor, and stir and react at 80°C for 5h under nitrogen protection to obtain polyurethane-polyurea composite polymer.

[0065] 7. Add 12g of ultra-high molecular weight polyethylene fiber, 22g of polyurethane-modified silicon carbide whisker shearing thickener, 2g of glyceryl monostearate, 7g of decabromodiphenyl ether and 4g of chloroprene rubber to 49g of polyurethane-polyurea composite polymer. Stir at 60°C for 30 minutes under nitrogen protection. Then add 1g of polydimethylsiloxane and 2g of triphenyl phosphite in sequence. Finally, add 1g of dimethyl silicone oil and continue stirring for 10 minutes to obtain a polyurethane modified composite coating with bulletproof and explosion-proof functions.

[0066] Example 3:

[0067] like Figure 1 As shown, a method for preparing a polyurethane modified composite coating with bulletproof and explosion-proof functions includes the following steps:

[0068] 1. Add 98g of silicon carbide whiskers to a stirrer, and under nitrogen protection, add 2g of 3-isocyanate-propyltriethoxysilane dropwise to the stirrer while stirring.

[0069] After adding 2,3-isocyanate-propyltriethoxysilane, continue stirring for 10 minutes to obtain modified silicon carbide whiskers. Dry them at 100°C for 2 hours under nitrogen protection and seal them for later use.

[0070] 3. Add 30g of polyurethane to 50g of xylene, stir and dissolve at 50℃, then add 20g of sealed modified silicon carbide whiskers, stir for 10min to obtain polyurethane-modified silicon carbide whisker shear thickening liquid.

[0071] 4. Add 60g DMF, 12g tetramethylisophthalamide diisocyanate, 27.5g polyester polyol and 0.5g organotin catalyst to the reactor, stir and react at 60℃ for 3h under nitrogen protection to obtain polyurethane prepolymer dispersion.

[0072] 5. Add 70g DMF, 25g tetramethylisophthalamide diisocyanate and 5g 1,12-diaminododecane to a reactor and stir at 40°C for 40 min under nitrogen protection to obtain a polyurea prepolymer dispersion.

[0073] 6. Add 74g of polyurethane prepolymer dispersion, 25.5g of polyurea prepolymer dispersion and 0.5g of organotin catalyst to a reactor, and stir and react at 50°C for 8 hours under nitrogen protection to obtain polyurethane-polyurea composite polymer.

[0074] 7. Add 8g of ultra-high molecular weight polyethylene fiber, 15g of polyurethane-modified silicon carbide whisker shearing thickener, 2g of alkylphenol polyoxyethylene ether phosphate, 5g of tricresyl phosphate and 5g of nitrile rubber to 60g of polyurethane-polyurea composite polymer. Stir at 45°C for 60min under nitrogen protection. Then add 2g of acrylic-ethyl acrylate copolymer and 1g of phenyl p-hydroxybenzoate in sequence. Finally, add 2g of polyoxypropylene glycerol ether and continue stirring for 20min to obtain a polyurethane modified composite coating with bulletproof and explosion-proof functions.

[0075] Example 4:

[0076] like Figure 1 As shown, a method for preparing a polyurethane modified composite coating with bulletproof and explosion-proof functions includes the following steps:

[0077] 1. Add 99g of silicon carbide whiskers to a stirrer, and under nitrogen protection, add 1g of tris(3-trimethoxysilylpropyl)isocyanurate dropwise to the stirrer while stirring.

[0078] 2. After adding tris(3-trimethoxysilylpropyl)isocyanurate, continue stirring for 5 minutes to obtain modified silicon carbide whiskers. Dry them at 85°C for 4 hours under nitrogen protection and seal them for later use.

[0079] 3. Add 40g of polyurethane to 30g of xylene, stir and dissolve at 60℃, then add 30g of sealed modified silicon carbide whiskers, stir for 30min to obtain polyurethane-modified silicon carbide whisker shear thickening liquid.

[0080] 4. Add 40g DMF, 20g diphenylmethane diisocyanate, 39.9g polyester polyol and 0.1g organotin catalyst to the reactor, stir and react at 90℃ for 1h under nitrogen protection to obtain polyurethane prepolymer dispersion.

[0081] 5. Add 50g DMF, 40g diphenylmethane diisocyanate and 10g 1,14-tetradecanediamine to a reaction vessel, stir and react at 60℃ for 20min under nitrogen protection to obtain a polyurea prepolymer dispersion.

[0082] 6. Add 62g of polyurethane prepolymer dispersion, 37.9g ​​of polyurea prepolymer dispersion and 0.1g of organotin catalyst to a reactor, and stir and react at 80°C for 5h under nitrogen protection to obtain polyurethane-polyurea composite polymer.

[0083] 7. Add 15g of ultra-high molecular weight polyethylene fiber, 25g of polyurethane-modified silicon carbide whisker shearing thickening liquid, 1g of sodium polyacrylate, 8g of aluminum hydroxide and 3g of styrene-butadiene rubber to 44g of polyurethane-polyurea composite polymer, stir at 60℃ for 30min under nitrogen protection, then add 1g of polyether-modified polydimethylsiloxane and 2g of dilauryl thiodipropionate in sequence, and finally add 1g of polyoxyethylene glycerol ether, and continue stirring for 10min to obtain a polyurethane-modified composite coating with bulletproof and explosion-proof functions.

[0084] Example 5:

[0085] like Figure 1 As shown, a method for preparing a polyurethane modified composite coating with bulletproof and explosion-proof functions includes the following steps:

[0086] 1. Add 96g of silicon carbide whiskers to a stirrer, and under nitrogen protection, add 4g of 3-isocyanate-propyltrimethoxysilane dropwise to the stirrer while stirring.

[0087] After adding 2,3-isocyanate-propyltrimethoxysilane, continue stirring for 9 minutes to obtain modified silicon carbide whiskers. Dry them at 95°C for 3 hours under nitrogen protection and seal them for later use.

[0088] 3. Add 35g of polyurethane to 45g of xylene, stir and dissolve at 55℃, then add 20g of sealed modified silicon carbide whiskers, stir for 25min to obtain polyurethane-modified silicon carbide whisker shear thickening liquid.

[0089] 4. Add 55g DMF, 15g diphenylmethane diisocyanate, 29.8g polyester polyol and 0.2g organotin catalyst to the reactor, stir and react at 80℃ for 2h under nitrogen protection to obtain polyurethane prepolymer dispersion.

[0090] 5. Add 65g DMF, 30g m-phthalimide diisocyanate and 5g diamine to the reactor, stir and react at 50°C for 35min under nitrogen protection to obtain polyurea prepolymer dispersion;

[0091] 6. Add 68g of polyurethane prepolymer dispersion, 31.9g of polyurea prepolymer dispersion and 0.1g of organotin catalyst to a reactor, and stir and react at 70°C for 7h under nitrogen protection to obtain polyurethane-polyurea composite polymer.

[0092] 7. Add 10g of ultra-high molecular weight polyethylene fiber, 22g of polyurethane-modified silicon carbide whisker shearing thickener, 2g of BYK-190, 6g of diphenyl phosphate, and 4g of TPU to 52g of polyurethane-polyurea composite polymer. Stir at 55°C for 50 minutes under nitrogen protection. Then add 1.5g of polydimethylsiloxane and 1g of 2,6-di-tert-butyl-p-cresol in sequence. Finally, add 1.5g of polyoxypropylene glycerol ether and continue stirring for 15 minutes to obtain a polyurethane-modified composite coating with bulletproof and explosion-proof functions.

[0093] Example 6:

[0094] like Figure 1 As shown, a method for preparing a polyurethane modified composite coating with bulletproof and explosion-proof functions includes the following steps:

[0095] 1. Add 99.5g of silicon carbide whiskers to a stirrer, and under nitrogen protection, add 0.5g of 3-isocyanate-propyltrimethoxysilane dropwise to the stirrer while stirring.

[0096] After adding 2,3-isocyanate-propyltrimethoxysilane, continue stirring for 6 minutes to obtain modified silicon carbide whiskers. Dry them at 90°C for 2.5 hours under nitrogen protection and seal them for later use.

[0097] 3. Add 38g of polyurethane to 42g of xylene, stir and dissolve at 58℃, then add 20g of sealed modified silicon carbide whiskers, stir for 15min to obtain polyurethane-modified silicon carbide whisker shear thickening liquid.

[0098] 4. Add 48g DMF, 17g tetramethylisophthalamide diisocyanate, 34.9g polyester polyol and 0.1g organotin catalyst to the reactor, stir and react at 85℃ for 1.5h under nitrogen protection to obtain polyurethane prepolymer dispersion.

[0099] 5. Add 58g DMF, 32g m-phthalimide diisocyanate and 10g diamine to the reactor, stir and react at 55℃ for 25min under nitrogen protection to obtain polyurea prepolymer dispersion.

[0100] 6. Add 70g of polyurethane prepolymer dispersion, 29.8g of polyurea prepolymer dispersion and 0.2g of organotin catalyst to a reactor, and stir and react at 75°C for 6.5h under nitrogen protection to obtain polyurethane-polyurea composite polymer.

[0101] 7. Add 9g of ultra-high molecular weight polyethylene fiber, 18g of polyurethane-modified silicon carbide whisker shearing thickener, 2g of alkylphenol polyoxyethylene ether phosphate, 7g of tricresyl phosphate and 3g of styrene-butadiene rubber to 58g of polyurethane-polyurea composite polymer. Stir at 50°C for 40min under nitrogen protection. Then add 1g of acrylic-ethyl acrylate copolymer and 1g of triphenyl phosphite in sequence. Finally add 1g of polyoxyethylene glycerol ether and continue stirring for 12min to obtain a polyurethane modified composite coating with bulletproof and explosion-proof functions.

[0102] Comparative Example 1:

[0103] A method for preparing a polyurethane-modified composite coating with bulletproof and explosion-proof functions includes the following steps:

[0104] 1. Add 35g of polyurethane to 40g of xylene, stir and dissolve at 55℃, then add 25g of silicon carbide whiskers and stir for 20min to obtain polyurethane-silicon carbide whisker shear thickening liquid.

[0105] 2. Add 50g DMF, 15g isophthalamide diisocyanate, 34.8g polyester polyol and 0.2g organotin catalyst to the reactor, stir and react at 75℃ for 2h under nitrogen protection to obtain polyurethane prepolymer dispersion.

[0106] 3. Add 60g DMF, 30g m-phthalimide diisocyanate and 10g heptanediamine to a reaction vessel, stir and react at 50°C for 30min under nitrogen protection to obtain a polyurea prepolymer dispersion.

[0107] 4. Add 70g of polyurethane prepolymer dispersion, 29.8g of polyurea prepolymer dispersion and 0.2g of organotin catalyst to a reactor, and stir and react at 65℃ for 6h under nitrogen protection to obtain polyurethane-polyurea composite polymer.

[0108] 5. Add 10g of ultra-high molecular weight polyethylene fiber, 24g of polyurethane-modified silicon carbide whisker shearing thickener, 2g of sodium polymethacrylate, 6g of triethyl phosphate and 4g of ethylene propylene rubber to 50g of polyurethane-polyurea composite polymer. Stir at 50℃ for 45min under nitrogen protection. Then add 1.5g of polyether-modified polydimethylsiloxane and 1.5g of zinc stearate in sequence. Finally, add 1g of polyoxyethylene glycerol ether and continue stirring for 12min to obtain a polyurethane-modified composite coating with bulletproof and explosion-proof functions.

[0109] Comparative Example 2:

[0110] A method for preparing a polyurethane-modified composite coating with bulletproof and explosion-proof functions includes the following steps:

[0111] 1. Add 98g of silicon carbide whiskers to a stirrer, and under nitrogen protection, add 2g of 3-isocyanate-propyltriethoxysilane dropwise to the stirrer while stirring;

[0112] After adding 2,3-isocyanate-propyltriethoxysilane, continue stirring for 10 minutes to obtain modified silicon carbide whiskers. Dry them at 100°C for 2 hours under nitrogen protection and seal them for later use.

[0113] 3. Add 30g of polyurethane to 50g of xylene, stir and dissolve at 50℃, then add 20g of sealed modified silicon carbide whiskers, stir for 10min to obtain polyurethane-modified silicon carbide whisker shear thickening liquid.

[0114] 4. Add 8g of ultra-high molecular weight polyethylene fiber, 15g of polyurethane-modified silicon carbide whisker shearing thickening liquid, 2g of alkylphenol polyoxyethylene ether phosphate, 5g of tricresyl phosphate and 5g of nitrile rubber to 60g of polyurea resin. Stir at 45℃ for 60min under nitrogen protection. Then add 2g of acrylic-ethyl acrylate copolymer and 1g of phenyl p-hydroxybenzoate in sequence. Finally add 2g of polyoxypropylene glycerol ether and continue stirring for 20min to obtain a polyurethane modified composite coating with bulletproof and explosion-proof functions.

[0115] Comparative Example 3:

[0116] A method for preparing a polyurethane-modified composite coating with bulletproof and explosion-proof functions includes the following steps:

[0117] 1. Add 38g of polyurethane to 42g of xylene, stir and dissolve at 58℃, then add 20g of silicon carbide whiskers and stir for 15min to obtain polyurethane-silicon carbide whisker shear thickening liquid.

[0118] 2. Add 9g of ultra-high molecular weight polyethylene fiber, 18g of polyurethane-modified silicon carbide whisker shearing thickening liquid, 2g of alkylphenol polyoxyethylene ether phosphate, 7g of tricresyl phosphate and 3g of styrene-butadiene rubber to 58g of polyurea resin, stir at 50℃ for 40min under nitrogen protection, then add 1g of acrylic-ethyl acrylate copolymer and 1g of triphenyl phosphite in sequence, and finally add 1g of polyoxyethylene glycerol ether, and continue stirring for 12min to obtain a polyurethane modified composite coating with bulletproof and explosion-proof functions.

[0119] Referring to the Chinese Chemical Society group standard "Spray-on Explosion-proof Elastomer Materials" (standard number T / CIESC 0019-2021), the mechanical properties of the prepared polyurethane modified composite coating were tested to demonstrate its explosion-proof and bulletproof functions.

[0120] Table 1. Test results of polyurethane modified composite coatings prepared in the examples and comparative examples.

[0121]

[0122] As shown in Table 1, the test data of the polyurethane modified composite coatings prepared in Examples 1-6 are better than those of Comparative Examples 1-3.

[0123] This is because, in the polyurethane-modified composite coatings with bulletproof and explosion-proof functions prepared in Examples 1-6, the polyurethane prepolymer and the polyurea prepolymer obtained from the reaction are further reacted through a chemical reaction between isocyanate groups and hydroxyl groups to obtain a polyurethane-polyurea composite polymer whose molecular chain contains both rigid networks with rigid groups such as benzene rings and urea groups, and flexible carbon chains derived from polyester polyols and long-chain diamines. Using this polyurethane-polyurea composite polymer as the matrix of the composite coating gives the composite coating excellent mechanical properties. Thus, when subjected to bullet or explosion impacts, it can absorb energy through deformation and resist penetration and crack propagation through the rigid network, thereby having excellent bulletproof and explosion-proof functions. Furthermore, the polyurethane-modified silicon carbide whisker shear thickening liquid causes the prepared composite coating to rapidly trigger a shear thickening effect when subjected to high-speed impacts, quickly hardening to resist penetration. Furthermore, in the polyurethane-modified silicon carbide whisker shear thickening liquid, the isocyanate-based silane coupling agent-modified silicon carbide whiskers contain a large number of isocyanate groups. On the one hand, this can improve the interfacial compatibility between inorganic whiskers and the organic matrix; on the other hand, it can further react with the amino or hydroxyl groups in the polyurethane-polyurea composite polymer to form strong chemical bonds. In addition, the polyurethane component, due to the principle of like compatibility, also promotes the compatibility between inorganic whiskers and the organic matrix. Therefore, it can reduce stress concentration in the composite coating and prevent interfacial debonding of the components. In summary, the polyurethane-modified silicon carbide whisker shear thickening liquid and the polyurethane-polyurea composite polymer matrix work synergistically to further enhance the bulletproof and explosion-proof functions of the prepared composite coating.

[0124] In Comparative Example 1, the silicon carbide whiskers were not modified, thus failing to improve the interfacial compatibility between the inorganic whiskers and the organic matrix; nor could they react with the amino or hydroxyl groups in the polyurethane-polyurea composite polymer to form strong chemical bonds, resulting in poor explosion-proof and bulletproof performance. In Comparative Example 2, the matrix of the composite coating was only polyurea resin, which lacked excellent mechanical properties, thus the resulting composite coating also had poor explosion-proof and bulletproof performance. In Comparative Example 3, the composite coating neither modified the silicon carbide whiskers nor used a polyurethane-polyurea composite polymer as the matrix, therefore exhibiting the worst explosion-proof and bulletproof performance.

[0125] The above results demonstrate and describe the basic principles and main features of this application, as well as its advantages.

[0126] Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the equivalents of the appended claims.

Claims

1. A polyurethane modified composite coating having a bulletproof and blastproof function, characterized in that, The polyurethane-polyurea composite polymer is obtained by chemical reaction of a hydroxyl-terminated polyurethane prepolymer and an isocyanate-terminated polyurea prepolymer; the hydroxyl-terminated polyurethane prepolymer is obtained by chemical reaction of a diisocyanate containing a benzene ring and a polyester polyol; the isocyanate-terminated polyurea prepolymer is obtained by chemical reaction of a diisocyanate containing a benzene ring and a diamine; the additives include a dispersing agent, a leveling agent, a defoaming agent, a stabilizer, a flame retardant, and a toughening agent; in the polyurethane-modified silicon carbide whisker shear thickening fluid, the modified silicon carbide whisker is a silicon carbide whisker modified by an isocyanate silane coupling agent; the mass ratio of the silicon carbide whisker to the isocyanate silane coupling agent is (95-99):(1-5); the mass ratio of the polyurethane-polyurea composite polymer, the ultra-high molecular weight polyethylene fiber, the polyurethane-modified silicon carbide whisker shear thickening fluid, the dispersing agent, the leveling agent, the defoaming agent, the stabilizer, the flame retardant, and the toughening agent is (40-60):(8-15):(15-25):(1-3):(1-2):(1-2):(1-2):(5-8):(3-5).

2. The polyurethane modified composite coating with bulletproof and explosion-proof function according to claim 1, characterized in that, The diisocyanate containing a benzene ring includes any one of m-xylylene diisocyanate, tetramethyl-m-xylylene diisocyanate, and diphenylmethane diisocyanate.

3. The polyurethane modified composite coating with bulletproof and explosion-proof function according to claim 1, characterized in that, The diamine includes any one of heptamethylenediamine, decanediamine, 1,12-diaminododecane, and 1,14-tetradecanediamine.

4. The method for preparing polyurethane modified composite coating with bulletproof and explosion-proof function according to any one of claims 1-3, characterized in that, The method comprises the following steps: The silicon carbide whisker is added to a stirrer, and the isocyanate silane coupling agent is added dropwise to the stirrer under nitrogen protection while stirring; After the isocyanate silane coupling agent is added, stirring is continued for 5-10 min, and the modified silicon carbide whisker is obtained by drying at 80-100°C for 2-4 h under nitrogen protection, and is sealed for later use; The polyurethane is added to xylene, and after stirring and dissolving at 50-60°C, a mixed solution is obtained, the modified silicon carbide whisker sealed for later use is added, and stirring is performed for 10-30 min to obtain a polyurethane-modified silicon carbide whisker shear thickening fluid; DMF, a diisocyanate containing a benzene ring, a polyester polyol, and an organic tin catalyst are put into a reaction kettle, and stirring reaction is performed at 60-90°C for 1-3 h under nitrogen protection to obtain a hydroxyl-terminated polyurethane prepolymer; DMF, a diisocyanate containing a benzene ring, and a diamine are put into a reaction kettle, and stirring reaction is performed at 40-60°C for 20-40 min under nitrogen protection to obtain an isocyanate-terminated polyurea prepolymer; The hydroxyl-terminated polyurethane prepolymer, the isocyanate-terminated polyurea prepolymer, and an organic tin catalyst are put into a reaction kettle, and stirring reaction is performed at 50-80°C for 5-8 h under nitrogen protection to obtain a polyurethane-polyurea composite polymer; The ultrahigh molecular weight polyethylene fiber, the polyurethane-modified silicon carbide whisker shear thickening liquid, a dispersing agent, a flame retardant and a toughening agent are added into the polyurethane-polyurea composite polymer, and then the mixture is stirred at 45-60 DEG C under nitrogen protection for 30-60 min; then a leveling agent and a stabilizer are added in sequence, and finally a defoaming agent is added, and the mixture is continuously stirred for 10-20 min, so that the polyurethane-modified composite coating with bulletproof and explosion-proof functions is obtained.

5. The method for preparing polyurethane modified composite coating with bulletproof and explosion-proof function according to claim 4, characterized in that, In the process of preparing the polyurethane-modified silicon carbide whisker shear thickening liquid, the mass ratio of the xylene, the polyurethane and the modified silicon carbide whisker is (30-50):(25-40):(15-30).

6. The method for preparing polyurethane modified composite coating with bulletproof and explosion-proof function according to claim 4, characterized in that, In the process of preparing the hydroxyl-terminated polyurethane prepolymer, the mass ratio of the DMF, the diisocyanate containing benzene ring, the polyester polyol and the organic tin catalyst is (40-60):(10-20):(30-40):(0.1-0.5).

7. The method for preparing polyurethane modified composite coating with bulletproof and explosion-proof function according to claim 4, characterized in that, In the process of preparing the isocyanate-terminated polyurea prepolymer, the mass ratio of the DMF, the diisocyanate containing benzene ring and the diamine is (50-70):(20-40):(5-10).

8. The method for preparing polyurethane modified composite coating with bulletproof and explosion-proof function according to claim 4, characterized in that, In the process of preparing the polyurethane-polyurea composite polymer, the mass ratio of the hydroxyl-terminated polyurethane prepolymer, the isocyanate-terminated polyurea prepolymer and the organic tin catalyst is (62-74):(25-42):(0.1-0.5).

Images