Multi synergistically enhanced polyurea elastomer material, its preparation method and application

Abstract

The present application relates to polyurea elastomer material preparation technical field, specifically for multiple synergistic reinforced polyurea elastomer material and its preparation method and application, the material is prepared by the reaction of specific A component and B component, innovatively integrated synergistic flame retardant system, multi-scale reinforcing system and intelligent protection system, through the synergistic formation of ceramic skeleton carbon layer of phosphorus-nitrogen-silicon, the synergistic realization of stress step-by-step dissipation of nanometer-micron, and the synergistic provision of dynamic long-acting protection of self-repairing-hydrophobic, the present application solves the problem that the performance of traditional protective materials is single and mutually restricted. The preparation method adopts unique nano pre-dispersion and multi-step feeding process. Compared with the prior art, the material of the present application simultaneously has the performance of extreme fireproofing, heat insulation, impact resistance, wear resistance and self-repairing waterproofing, and can fundamentally improve the safety and reliability of new energy automobile battery pack and chassis.

Description

Technical Field

[0001] This invention relates to the field of polyurea elastomer material preparation technology, specifically to multi-synergistic reinforced polyurea elastomer materials, their preparation methods, and applications. Background Technology

[0002] With the explosive growth of the global new energy vehicle (NEV) industry, the safety of power battery systems has become a core bottleneck restricting the industry's development and an absolute focus of consumer attention. As the energy center of the entire vehicle, the battery pack faces complex and ever-changing safety threats from multiple dimensions and extremes, including physical, thermal, and chemical factors, under complex and varied driving conditions.

[0003] When a vehicle is traveling at high speed, the chassis inevitably encounters the risk of violent impacts from road debris and foreign objects, scratches from sharp objects, and even punctures from accidental bottoming out. Once these physical damages affect the battery pack casing, they can easily cause internal cell deformation and short circuits, potentially triggering catastrophic thermal runaway. Whether caused by an external fire source or internal thermal runaway due to a single cell failure, the resulting high temperatures and flames will spread rapidly within the battery pack. Effectively blocking the spread of heat and flames in the early stages of thermal runaway, thus providing occupants with precious "golden escape time," is a critical challenge that current battery safety technology urgently needs to overcome. The battery pack and chassis are constantly exposed to corrosive environments such as humidity, salt spray, acid rain, and de-icing agents, while also enduring continuous vibration and temperature cycling. This necessitates that protective materials possess stable and reliable waterproof sealing and corrosion resistance throughout their entire lifespan.

[0004] To address these challenges, existing technological solutions have significant limitations: traditional physical protection solutions, such as adding metal or composite material skid plates, while providing some impact resistance, significantly increase vehicle weight, sacrifice driving range, and may cause secondary damage after deformation. Traditional functional coating solutions, such as PVC chassis armor, asphalt coatings, or ordinary polyurethane coatings, generally suffer from limited functionality and low performance. More importantly, they are subject to irreconcilable performance constraints: for example, simple filler blending to improve flame retardancy often significantly sacrifices the material's flexibility and impact resistance, leading to embrittlement and cracking; while formulations pursuing high flexibility typically lack sufficient hardness and wear resistance.

[0005] Therefore, there is an urgent need in this field for a protective material that is no longer a simple compromise or superposition of various performance indicators, but rather achieves a simultaneous leap and organic unity of multiple core properties such as flame retardancy, toughness, wear resistance, and long-lasting waterproofing through molecular-level design and deep synergy of multiple systems, so as to provide an integrated safety solution for new energy vehicles. Summary of the Invention

[0006] According to the deficiencies in the prior art above, the purpose of the present application is to provide a multiple synergistically reinforced polyurea elastomer material, which provides a "firewall" level of thermal protection capability and physical impact resistance, and fundamentally improves the survival capability of new energy vehicle core components under extreme accidents.

[0007] Another purpose of the present application is to provide a preparation method of a multiple synergistically reinforced polyurea elastomer material, which breaks the design bottleneck of mutual restriction of traditional material performance such as "flame retardant / strong and tough / abrasion resistant", and realizes the synchronous enhancement and overall improvement of all key safety indicators.

[0008] The third purpose of the present application is to provide an application of a multiple synergistically reinforced polyurea elastomer material, which is used for the safety protection of battery pack shell, chassis or high-voltage components of new energy vehicles.

[0009] The present application is implemented by using the following technical solutions:

[0010] The multiple synergistically reinforced polyurea elastomer material is prepared by reaction of A component and B component, wherein the mass ratio of the A component to the B component is 1: (1.05-1.12);

[0011] The A component is an isocyanate prepolymer with NCO content of 14.5%-16.5%;

[0012] The B component is a composite functional amine mixture, which contains, based on the total weight of the main resin and amine chain extender being 100 parts:

[0013] a. a phosphorus-nitrogen-silicon synergistic flame retardant system, the amount of which is 23.5-68 parts;

[0014] b. a nano-micron multi-scale reinforcing system, the amount of which is 5.7-30 parts;

[0015] c. an intelligent protection system, the amount of which is 8-30 parts;

[0016] d. an auxiliary agent, the amount of which is 3-12 parts.

[0017] The NCO content of the A component is between 14.5% and 16.5%. When the NCO content is in this range, the ideal ratio of hard segment and soft segment can be formed after reacting with the amine group of the B component. If the NCO content is less than 14.5%, the content of the hard segment will be insufficient, and the hardness, strength and wear resistance of the polyurea elastomer prepared will decrease. If the NCO content is higher than 16.5%, the content of the hard segment is too high, the material will become too hard and brittle, the elongation at break and impact resistance will be significantly reduced, and the toughness required for chassis protection cannot be met. The A component is prepared by reacting aromatic isocyanate (diphenylmethane diisocyanate, MDI) with polyether polyol. In order to improve the processability, it is preferred to use liquefied MDI or modified MDI to reduce the viscosity of the prepolymer at room temperature, facilitating storage and transportation.

[0018] The traditional flame-retardant polymer relies on the formation of a loose and brittle carbon layer. The present application overturns this mode through the "phosphorus (P)-nitrogen (N)-silicon (Si)-carbon (C)" four-element synergy. The principle lies in the "in-situ self-generated ceramic skeleton reinforced intumescent carbon layer": when heated, APP-II decomposes to produce polyphosphoric acid, which acts as a strong dehydrating agent and acid catalyst to promote the efficient dehydration and crosslinking of phytic acid in PA-MMT and the polyurea matrix, forming the basic intumescent carbon layer (C-source); at the same time, the nanometer montmorillonite (Si-source) layers in PA-MMT act as high-temperature-resistant "bricks" to form an initial physical isolation barrier in the carbon layer. NH3, N2 and other non-combustible gases released by APP-II and MCA (N-source) dilute the oxygen concentration in the gas phase and cool the flame; at the same time, these gases make the molten polymer matrix foam, forming a porous structure and reducing the thermal conductivity of the carbon layer. More importantly, the phosphate reacts with the nitrogen-containing compound at high temperature to form a P-N crosslinked structure (phosphorus-oxygen-nitrogen compound) with extremely high thermal stability, which essentially improves the heat resistance limit and oxidation resistance of the carbon layer skeleton. At higher temperatures, polyphosphoric acid will react with the hydroxyl groups or siloxane bonds on the surface of the montmorillonite to generate in-situ inorganic phosphorus-silicate or phosphorus-oxygen-silicon ceramic phases. This ceramic phase is uniformly distributed at the nanoscale and anchored in the P-N crosslinked carbon skeleton, like introducing high-strength ceramic reinforcement into concrete. It completely changes the physical properties of the carbon layer: from the "loose and brittle" of traditional organic carbon to the "dense and tough" organic-inorganic hybrid ceramic body. This ceramic skeleton greatly inhibits the shrinkage and cracking of the carbon layer, enabling it to maintain structural integrity under long-term flame scouring, and the heat insulation performance thus increases exponentially, realizing the qualitative change from "flame retardant" to "fireproof and heat insulation wall".

[0019] The phosphorus-nitrogen-silicon synergistic flame-retardant system comprises 14-36 parts of ammonium polyphosphate, 7-20 parts of phosphorus-containing modified layered silicate, and 2.5-12 parts of nitrogen-based flame retardant.

[0020] The phosphorus-containing modified layered silicate is phytic acid modified montmorillonite.

[0021] The phosphorus-nitrogen-silicon synergistic flame retardant system is preferably composed of "ammonium polyphosphate (APP)", "phosphorus-containing modified layered silicate" and "nitrogen-based flame retardant". In the preferred embodiment, it is specifically "APP-II", "phytic acid modified montmorillonite (PA-MMT)" and "melamine cyanurate (MCA)". The amount of APP-II is 10-18 parts. Below 10 parts, the flame retardant effect is acceptable but the limiting oxygen index is low; above 18 parts, the mechanical properties will be sacrificed due to excessive filler amount. The amount of PA-MMT is 5-10 parts. It is the key to realize "P-Si synergy" to form a high-strength ceramic carbon layer. Below 5 parts, the carbon layer is not strong enough; above 10 parts, the material flowability and elongation may be affected due to too many nano-sheets. The amount of MCA is 2-6 parts. It is used to provide gas phase synergism and form P-N synergy with APP.

[0022] The nano-micro multi-scale reinforcing system comprises 0.7-6 parts of carbon-based nanomaterials, 2.5-12 parts of high-toughness microfibers, and 2.5-12 parts of high-hardness nanoparticles.

[0023] The carbon-based nanomaterials are functionalized graphene oxide (f-GO), the high-toughness microfibers are aramid fibers, and the high-hardness nanoparticles are nano-silicon carbide (Nano-SiC). The amount of f-GO is 0.5-3 parts. As "nanoswages", the key is dispersion. Below 0.5 parts, the interface reinforcing effect is not obvious; above 3 parts, agglomeration occurs easily, which becomes a defect point instead. The amount of aramid fibers is 2-6 parts. It is the main force to resist macroscopic puncture and tearing. Without aramid, the impact resistance of the material decreases sharply, and the elongation at break is greatly reduced, making the material brittle. The amount of Nano-SiC is 2-6 parts. It is the core to improve wear resistance. Without SiC, the wear and scratch resistance decreases significantly.

[0024] Traditional reinforcement methods often have to make a choice between hardness and toughness, and it is difficult to achieve both. The present application realizes the ordered transmission and step-by-step dissipation of stress in different scales by constructing a "nano-micron" cross-scale reinforcement network: Amino-functionalized graphene oxide (f-GO) acts as countless "nanosize rivets", and its two-dimensional sheet structure and surface functional groups can simultaneously form strong chemical bonds or hydrogen bonds with the polyurea matrix and aramid fibers, firmly locking the originally weak filler-matrix interface and preventing interfacial debonding during impact, which is the basis for the synergistic work of the entire reinforcement system. When a microcrack attempts to expand, it will encounter high-modulus f-GO sheets and high-hardness Nano-SiC particles. These nanoparticles will force the crack path to deflect, branch, and even form a micro-plastic deformation around the nanoparticles, thereby dissipating a large amount of energy and greatly improving the material's fracture toughness and cracking threshold. When the impact energy is huge, microcracks converge into macrocracks, and aramid fibers embedded in the matrix begin to play a "rebar" role. The crack propagates to the fiber, and must pass through high-energy processes such as fiber pull-out, fiber fracture, or fiber bridging to continue. Especially the fiber pull-out process, accompanied by a large amount of interfacial friction work, can absorb most of the impact energy, thereby preventing catastrophic penetration damage. The essence of the present application is that the nano-reinforcement is not working independently. The strong interface network constructed by f-GO enables the impact stress to be efficiently transmitted from the polyurea matrix to the high-toughness aramid fibers, activating the full potential of the aramid fibers. Without this efficient "stress transmission chain", the aramid fibers are easily pulled out from the weak interface when the stress is insufficient, and cannot exert their maximum energy absorption effect. Therefore, the "rivet" effect of f-GO and the "bone and muscle" effect of aramid fibers are interdependent and synergistically achieve the overall strengthening and toughening effect.

[0025] The intelligent protection system comprises 5.5-20 parts of diamine containing reversible dynamic chemical bonds, and 2.5-10 parts of functional amine containing fluorosilane groups. The value of the intelligent system lies in "dynamic" and "long-acting". Minor damage can be self-repaired, which makes the super-hydrophobic surface have the possibility of recovery even if it is scratched, thereby maintaining high-level waterproof and anticorrosion ability for a long time, which is not possessed by traditional coatings.

[0026] The traditional protection is passive and static. The application gives the material the ability of active adaptation and self-recovery by introducing dynamic chemical bonds and low surface energy molecules: the introduced disulfide bond diamine forms reversible dynamic crosslinking points in the polyurea network. When the material is subjected to external force and microcracks are generated, these stress-concentrated disulfide bonds will preferentially break, absorbing energy and preventing the crack from evolving into catastrophic fracture. After the external force is removed, these broken sulfur radicals can re-bond at room temperature or under mild heating conditions through exchange reactions, thus "healing" the microcracks and restoring the mechanical integrity and air tightness of the material. The superhydrophobicity of the coating depends on the low surface energy substances (fluorosilicon segments) and the micro-rough structure of the surface. When the surface is scratched and damaged, the water resistance will decrease. The synergy of the application is that the self-repairing process not only repairs the structure, but also repairs the function. When the microcracks heal, the movement of the polymer segments will prompt the "reserved" fluorosilane-containing groups inside the system to migrate to the newly exposed surface, to some extent, to rebuild the low surface energy interface, and to achieve partial or complete recovery of hydrophobicity. This is an intelligent closed loop of "damage-response-repair-function regeneration", which ensures that the coating can maintain high-level water and corrosion resistance throughout the service cycle, realizing the leap from "static waterproofing" to "dynamic long-term sealing".

[0027] The main resin is an amino-terminated polyether, and the amine chain extender is an aromatic diamine chain extender; the auxiliary agent is composed of a silane coupling agent, a dispersing agent, a defoaming agent and a pigment.

[0028] The main resin refers mainly to a high molecular weight amino-terminated compound, which reacts with isocyanate to form "soft segments" in the polyurea, giving the material excellent flexibility, elasticity and low temperature performance. The molecular weight of the main resin is usually between 1000 and 5000 g / mol. The main resin is an amino-terminated polyether, which can be one or a mixture of a di-functional amino-terminated polyoxypropylene glycol ether or a tri-functional amino-terminated polyoxypropylene glycol ether. The use of a mixture of the two can introduce moderate crosslinking while ensuring flexibility, improving the strength and resilience of the material.

[0029] The amine chain extender refers mainly to a low molecular weight diamine or polyamine compound, which rapidly reacts with isocyanate to form "hard segments" in the polyurea, giving the material high strength, high modulus, high hardness and heat resistance. The amine chain extender is an aromatic diamine chain extender, which has moderate reactivity and can form high-strength rigid hard segments. Diethyl toluene diamine (DETDA) is preferred, as it is a liquid, easy to operate, fast in reaction speed, and can give the material excellent physical properties.

[0030] The preparation method of the multiple synergistically enhanced polyurea elastomer material comprises the following steps:

[0031] (1) Nanopre-dispersion step: mix the nanomaterials in the nano-micro multi-scale reinforcing system with a part of the main resin, and perform ultrasonic dispersion treatment with a power not less than 600W under the condition that the material temperature is lower than 50℃, or perform high-energy ball milling treatment, to prepare a nanocomposite master batch;

[0032] (2) Composite slurry preparation step: mix the nanocomposite master batch with the remaining main resin, then add the powder raw materials of the phosphorus-nitrogen-silicon synergistic flame retardant system and the microfibers in the nano-micro multi-scale reinforcing system, and perform high-speed shearing dispersion under the condition that the rotation speed is 1500-2500 rpm, until the slurry fineness is not greater than 60 μm;

[0033] (3) Functional blending step: after the slurry obtained in step (2) is cooled to below 45℃, the amine chain extender and the liquid raw materials of the intelligent protection system and the auxiliary agents are sequentially added, and the mixture is uniformly mixed under the condition that the rotation speed is 300-500 rpm;

[0034] (4) Defoaming step: the final mixture obtained in step (3) is subjected to vacuum defoaming treatment under the condition that the vacuum degree is not less than -0.09 MPa.

[0035] Specifically, raw material pretreatment:

[0036] Liquid raw material pretreatment (amino-terminated polyether, self-repairing amine, hydrophobic amine, etc.): Place the liquid raw material in a reaction kettle with stirring and vacuum interface, heat to 105-110℃ under stirring, start the vacuum pump, and dehydrate under the condition that the vacuum degree is ≤100 Pa for 1-2 hours until no bubbles escape. After cooling to room temperature, break the vacuum with dry nitrogen and seal for use.

[0037] Powder raw material pretreatment (APP-II, PA-MMT, MCA, Nano-SiC, carbon black, etc.): Place the powder raw material in a blast oven and bake at 110-120℃ for 4-6 hours. Take out and cool to room temperature in a desiccator for standby.

[0038] Fiber raw material pretreatment (aramid chopped fiber): dry in a vacuum oven at 80℃ for 4 hours, or dry in a vacuum at room temperature for 8 hours.

[0039] Detailed preparation steps of component B:

[0040] Step one: Preparation of nano-enhanced masterbatch; add f-GO and Nano-SiC to about 20%-30% of the total formulation amount of amino-terminated polyether, and perform high-energy dispersion. Dispersion method: ultrasonic dispersion or high-energy ball milling. Ultrasonic power: 600W-1000W. Dispersion time: 20-40 minutes. Temperature control: strictly control the material temperature below 50℃ by cooling jacket or intermittent operation.

[0041] Step two: Dispersion of composite slurry; mix the remaining main body resin with the nano masterbatch prepared in step one in a high-speed dispersion kettle, then start high-speed shearing, and then add all the powder raw materials (flame retardant system, fibers, etc.) in sequence. High-speed shearing speed: 1500-2500 rpm. Powder dispersion time: 30-60 minutes. Dispersion end criterion: use a doctor blade fineness gauge to detect that the slurry fineness is not greater than 60μm.

[0042] Step three: blending of functional liquid; after the dispersed slurry is cooled, all the remaining liquid amine raw materials and auxiliaries are added in sequence under low-speed stirring. Cooling target temperature: below 45℃. Low-speed stirring speed: 300-500 rpm.

[0043] Step four: vacuum degassing and packaging; the final mixture is subjected to vacuum degassing to remove air introduced during processing. Vacuum degree: not less than -0.09MPa. Degassing time: 10-30 minutes, or until no obvious bubbles escape.

[0044] The application of the multi-synergistically enhanced polyurea elastomer material is for the safety protection of battery pack shells, chassis or high-voltage components of new energy vehicles.

[0045] The safety protection is a protective coating formed by the polyurea elastomer material on the surface of the battery pack shell, chassis or high-voltage component, and the thickness of the protective coating is 2.0-3.0mm.

[0046] Compared with the prior art, the beneficial effects of the present application are:

[0047] (1) Extremely safe: provides a "firewall" level of thermal protection capability and physical impact resistance, fundamentally improving the survival ability of new energy vehicle core components under extreme accidents. It has the characteristics of micro-damage self-repairing, can resist daily scratches and long-term environmental corrosion, and ensures stable protection effect throughout the life cycle.

[0048] (2) It completely breaks through the design bottleneck of mutual restriction of traditional materials such as "flame retardant / strong / abrasion resistant" performance, realizes the synchronous enhancement and overall improvement of all key safety indicators. Adopting solvent-free spraying process, high production efficiency and environmental friendly, fully adapt to the fast pace and green demand of modern automobile manufacturing. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical scheme of the present application more clear, the present application is further described in detail as follows.

[0050] Liquefied MDI: Wannate® PM-200, commercially available product of Wanhua Chemical Group Co., Ltd.;

[0051] Polyether polyol (PPG): PPG-2000, VORANOL 220-110, commercially available product of Dow Chemical Company, USA;

[0052] Amino-terminated polyether: JEFFAMINE® D-2000, T-5000, commercially available product of Huntsman Corporation, USA;

[0053] Diethyltoluene diamine (DETDA): Ethacure® 100, commercially available product of Albemarle Corporation, USA;

[0054] Ammonium polyphosphate: Exolit® AP422 (APP-II), commercially available product of Clariant Corporation, Switzerland;

[0055] Melamine cyanurate: MCA, industrial grade, commercially available product of Shandong Shiny New Material Technology Co., Ltd.;

[0056] Functionalized graphene oxide (f-GO): SE2430-N (amino-functionalized), commercially available product of Changzhou Sixth Element Material Technology Co., Ltd.;

[0057] Aramid short-cut fiber: Twaron® 1099 (6 mm), commercially available product of Teijin Aramid B.V., Netherlands;

[0058] Nano-silicon carbide: β-SiC, particle size 50 nm, commercially available product of Shanghai Yaotian New Material Technology Co., Ltd.;

[0059] Inert filler: talcum powder, 1250 mesh, commercially available product of Guangxi Guihua Talc Co., Ltd.;

[0060] Silane coupling agent: KH-560, commercially available product of Nanjing Shuguang Silane Chemical Co., Ltd.;

[0061] Dispersant: BYK-111, commercially available product of BYK-Chemie GmbH, Germany;

[0062] Defoamer: BYK-052, commercially available product of BYK-Chemie GmbH, Germany;

[0063] Pigment: carbon black, Printex® U, commercially available product of Evonik Industries AG, Germany;

[0064] Sodium-based montmorillonite (Na-MMT): Nanomer® PGV, commercially available product of Nanocor, Inc., USA;

[0065] Phytic acid solution: 50 wt.% aqueous solution, analytical reagent (AR), commercially available from Shanghai Macklin Biochemical Science Co., Ltd.

[0066] Cystamine dihydrochloride: purity > 98%, commercially available from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0067] Epichlorohydrin (ECH): purity > 99%, commercially available from Dow Chemical Company, USA;

[0068] JEFFAMINE® D-400: polyetheramine, commercially available from Huntsman Corporation, USA;

[0069] (3-glycidyloxypropyl) methyldiethoxysilane: KBE-402, commercially available from Shin-Etsu Chemical Co., Ltd., Japan;

[0070] Nonafluorohexyltriethoxysilane: 1H, 1H, 2H, 2H-Perfluorohexyltriethoxysilane, purity > 97%, commercially available from Harbin Fluorine Source Chemical Co., Ltd.

[0071] The preparation method of phytic acid modified montmorillonite (PA-MMT) is as follows:

[0072] Take 100 g of sodium-based montmorillonite (Na-MMT, cation exchange capacity CEC ≈ 90 meq / 100 g), disperse in 2 L of deionized water, and stir at high speed for 24 hours to fully swell and disperse, forming a uniform suspension. Let stand for 48 hours, and take about 80% of the upper layer of the suspension. Under stirring, slowly add 1 M hydrochloric acid solution to the upper layer of the suspension, and adjust the pH value of the suspension to 3.0. Continue stirring for 4 hours. Take 60 g of phytic acid solution (50% wt.) and dilute to 500 mL with deionized water. Slowly add the diluted phytic acid solution to the prepared acidified montmorillonite suspension under vigorous stirring. The molar amount of phytic acid is much larger than the CEC value of montmorillonite to ensure sufficient ion exchange and physical adsorption. Transfer the mixed suspension to a constant temperature water bath and continue to stir at 60°C for 12 hours. Cool the reacted suspension to room temperature, transfer to a centrifuge tube, and centrifuge at 8000 rpm for 15 minutes, and discard the supernatant. Add deionized water to the precipitate, ultrasonic disperse for 10 minutes, and then centrifuge again. Repeat this washing-centrifugation process 5 times until the pH value of the supernatant approaches neutral (about 6.5-7.0).

[0073] The washed precipitate (filter cake) was placed in a freeze-dryer and freeze-dried for 48 hours to obtain a fluffy, powdery product, preventing agglomeration during the drying process. If a freeze-dryer is not available, the filter cake can also be dried in a vacuum oven at 80°C for 24 hours. The dried, blocky product was ground using a planetary ball mill or agate mortar and passed through a 200-mesh sieve to obtain a white, powdery product of phytic acid-modified montmorillonite (PA-MMT).

[0074] The self-repairing amine was chosen to be disulfide diamine (DSDD), and its preparation method was as follows:

[0075] In a 500 mL three-necked flask equipped with a condenser, a dropping funnel and a thermometer, 22.5 g (0.1 mol) of cystamine dihydrochloride and 200 mL of methanol were added. The stirring was started to dissolve it. 37.0 g (0.4 mol, 4 times excess) of epichlorohydrin was dissolved in 50 mL of methanol and loaded into a constant pressure dropping funnel. The three-necked flask was placed in an ice-water bath and cooled to 0-5°C. The epichlorohydrin solution was slowly added dropwise under vigorous stirring, and the dropping speed was controlled so that the temperature of the reaction system did not exceed 10°C. The dropping process took about 1-2 hours. After the dropping was completed, the ice bath was removed, and the reaction system was continuously stirred at room temperature (25°C) for 24 hours. After the reaction was completed, the system was cooled to 0-5°C again. A 20% (w / w) aqueous sodium hydroxide solution was slowly added dropwise, and the pH value was carefully adjusted to 10-11. This step was aimed at neutralizing the hydrochloride of cystamine and catalyzing the ring closure of the chlorohydrin intermediate to form an epoxy group. After neutralization, the stirring was continued at room temperature for 4 hours. The reaction mixture was removed by a rotary evaporator to remove most of the methanol. 200 mL of ethyl acetate and 100 mL of saturated brine were added to the remaining viscous material for extraction. The organic phase was separated, and the aqueous phase was extracted twice with 100 mL of ethyl acetate. All the organic phases were combined and dried overnight with anhydrous magnesium sulfate. The drying agent was removed by filtration, and the filtrate was evaporated by a rotary evaporator to obtain a yellowish viscous oil or semi-solid product. The crude product was dissolved in a minimum amount of hot ethanol, and after cooling, it was placed in a refrigerator to crystallize. The crystals were collected by filtration, washed with a small amount of cold ethanol, and dried under vacuum to obtain a high-purity disulfide diamine (DSDD) product.

[0076] The hydrophobic amine was chosen to be fluorosilicon-modified polyether amine, and its preparation method was as follows:

[0077] In a dry three-necked flask, 31.2 g (0.1 mol) of nonafluoro-hexyltriethoxysilane and 24.8 g (0.1 mol) of (3-glycidyloxypropyl)methyldiethoxysilane were added, together with 100 mL of anhydrous toluene. 2-3 drops of concentrated hydrochloric acid were added as catalyst, and a small amount of water (about 0.2 mL) was added to initiate the hydrolysis. The system was heated to 80°C, and the hydrolysis-condensation reaction was carried out under reflux for 8 hours under nitrogen protection. After the reaction was completed, the toluene and by-product ethanol were evaporated by a rotary evaporator to obtain a glycidyl ether intermediate containing fluorosilane groups (F-Si-Epoxy). In another dry three-necked flask, 40.0 g (0.1 mol) of JEFFAMINE® D-400, which had been previously vacuum-dried, and 150 mL of anhydrous toluene were added. The entire F-Si-Epoxy intermediate prepared in Step 1 was dissolved in 50 mL of anhydrous toluene and loaded into a dropping funnel. The three-necked flask was heated to 100°C. The F-Si-Epoxy solution was slowly added dropwise under stirring. The amino groups of the JEFFAMINE® D-400 would undergo ring-opening reaction with the epoxy groups. After the addition was completed, the reaction was continued at 100°C for 12 hours to ensure that the reaction was complete. After the reaction was completed, it was cooled to room temperature. The solvent toluene was evaporated by a rotary evaporator. The obtained viscous liquid product was subjected to thin film distillation or vacuum distillation at 100°C under high vacuum (<10 Pa) to remove unreacted JEFFAMINE® D-400 and small molecular impurities. Finally, a clear, light yellow viscous liquid, which was the target product of fluorosilicon-modified polyether amine, was obtained.

[0078] The preparation method of the A component prepolymer is as follows: in a reaction kettle equipped with stirring, thermometer and nitrogen protection, a metered amount of polyether polyol (PPG, molecular weight 2000 g / mol) was added, and dehydrated at 110°C for 1 hour. After cooling to 50°C, liquid MDI was slowly added dropwise under stirring, and the temperature was controlled not to exceed 80°C. After the addition was completed, the reaction was carried out at 78°C for 3 hours, and the -NCO content was determined by titration with di-n-butylamine (GB / T12009.5) for timed sampling until the target value was reached. After cooling, a stabilizer was added, and the product was sealed and stored. The ratio of raw materials of the A component prepolymer and test results are shown in Table 1.

[0079] The 'adjuvant' described in all examples and comparative examples is composed of the following components in a weight ratio of silane coupling agent (KH-560): dispersant (BYK-111): defoamer (BYK-052): pigment (carbon black) = 1.5:1:0.5:1.5.

[0080] Test method:

[0081] Tensile strength: GB / T528-2009;

[0082] Elongation at break: GB / T528-2009;

[0083] Impact strength: GB / T 1732-1993;

[0084] Adhesion (peel method): GB / T 5210-2006;

[0085] Abrasion resistance (Taber method): GB / T 1768-2006;

[0086] Flame resistance (vertical burning method): GB / T 2408-2008;

[0087] Water contact angle:

[0088] Using a contact angle meter, a 5 μL drop of deionized water was dropped on the surface of the coating placed horizontally.

[0089] After the water drop was stable (about 5 seconds), the drop profile was captured by the instrument software, and the static contact angles on the left and right sides were calculated, and the average value was taken. Each group of tests 5 different positions, take the final average value.

[0090] Self-repairing efficiency:

[0091] Cut the standard tensile sample, and use a sharp blade to cut a scratch in the center of the sample, perpendicular to the tensile direction, with a depth of about 50% of the sample thickness.

[0092] Immediately test the tensile strength of the part of the sample with the scratch (original damage strength).

[0093] Place the remaining sample with the scratch in a constant temperature oven at 60°C and heat treat for 2 hours.

[0094] After cooling to room temperature, test the tensile strength of the repaired sample.

[0095] Self-repairing efficiency (%) = (repaired strength - original damage strength) / (unscratched sample strength - original damage strength) x 100%.

[0096] Pre-treatment of raw materials:

[0097] Pre-treatment of liquid raw materials (amino-terminated polyether, self-repairing amine, hydrophobic amine, etc.): Place the liquid raw material in a reaction kettle with stirring and vacuum interface, heat to 108°C under stirring, start the vacuum pump, and dehydrate under a vacuum of 100 Pa for 2 hours until no bubbles escape. After cooling to room temperature, break the vacuum with dry nitrogen and seal for use.

[0098] Pre-treatment of powder raw materials (APP-II, PA-MMT, MCA, Nano-SiC, carbon black, etc.): Place the powder raw material in a forced air oven and bake at 115°C for 5 hours. After taking out, cool to room temperature in a desiccator for use.

[0099] Fiber raw material pretreatment (aramid short fiber): dried in a vacuum oven at 80°C for 4 hours, or vacuum dried at room temperature for 8 hours.

[0100] In the examples, the main resin is mixed by JEFFAMINE® D-2000 with a two functionality and JEFFAMINE® T-5000 with a three functionality. Among them, JEFFAMINE® D-2000 is used as the main component of linear chain growth, which provides excellent flexibility and elongation at break; while JEFFAMINE® T-5000 introduces crosslinking points to form a three-dimensional network structure to improve the tensile strength, hardness and resilience of the material. By adjusting the ratio of the two, the final mechanical properties of the polyurea material can be precisely controlled.

[0101] Example 1

[0102] The multi-synergistic reinforced polyurea elastomer material comprises:

[0103] The A component is selected: isocyanate prepolymer with NCO content of 14.53%; the mass ratio of A component to B component is 1:1.1;

[0104] The B component formula (100 parts): JEFFAMINE® D-2000: 47 parts; JEFFAMINE® T-5000: 3 parts; DETDA: 20 parts; APP-II: 10 parts; PA-MMT: 5 parts; MCA: 2 parts; f-GO: 0.5 parts; Aramid: 2 parts; Nano-SiC: 2 parts; self-repairing amine: 4 parts; hydrophobic amine: 2 parts; auxiliary agent: 2.5 parts.

[0105] The preparation steps are:

[0106] Nanopre-dispersion: take 10 parts of amino-terminated polyether, add 0.5 parts of f-GO and 2 parts of Nano-SiC. Under cooling conditions, use 600W ultrasonic dispersion for 20 minutes, the material temperature is controlled below 48°C, and the master batch is prepared.

[0107] Composite slurry dispersion: mix the remaining 40 parts of amino-terminated polyether with the above master batch. Turn on high-speed dispersion, speed 1500 rpm, add 10 parts of APP-II, 5 parts of PA-MMT, 2 parts of MCA in turn, and disperse for 20 minutes. Then reduce the speed to 800 rpm, add 2 parts of Aramid fiber, and continue to disperse for 10 minutes. The final fineness is 60μm.

[0108] Functional blending: cool the slurry to 45°C. Under low-speed stirring at 400 rpm, add 4 parts of self-repairing amine, 2 parts of hydrophobic amine, 20 parts of DETDA and 2.5 parts of auxiliary agent in turn, and mix for 15 minutes.

[0109] Defoaming: defoaming for 10 minutes under -0.09 MPa vacuum, to obtain.

[0110] Example 2

[0111] The multiple synergistically reinforced polyurea elastomer material comprises:

[0112] The A component is selected from: isocyanate prepolymer with NCO content of 15.52%; the mass ratio of the A component to the B component is 1:1.09;

[0113] The B component formula (100 parts): JEFFAMINE®D-2000: 33 parts; JEFFAMINE®T-5000: 7 parts; DETDA: 18 parts; APP-II: 18 parts; PA-MMT: 10 parts; MCA: 6 parts; f-GO: 1 part; Aramid: 4 parts; Nano-SiC: 4 parts; self-repairing amine: 4 parts; hydrophobic amine: 2 parts; auxiliary agent: 3 parts.

[0114] The preparation steps are:

[0115] Nano-pre-dispersion: take 10 parts of amino-terminated polyether, add 1 part of f-GO and 4 parts of Nano-SiC. Under cooling conditions, use 800W ultrasonic dispersion for 30 minutes, and control the material temperature below 45°C to prepare the master batch.

[0116] Composite slurry dispersion: mix the remaining 30 parts of amino-terminated polyether with the above master batch. Start high-speed dispersion at 2000 rpm, and then add 18 parts of APP-II, 10 parts of PA-MMT, and 6 parts of MCA in sequence, and disperse for 25 minutes. Then, reduce the speed to 1000 rpm, add 4 parts of Aramid fiber, and continue to disperse for 15 minutes. The final fineness is detected to be 55μm.

[0117] Functional blending: cool the slurry to 40°C. Under low-speed stirring at 400 rpm, add 4 parts of self-repairing amine, 2 parts of hydrophobic amine, 18 parts of DETDA, and 3 parts of auxiliary agent in sequence, and mix for 20 minutes.

[0118] Defoaming: defoaming for 20 minutes under -0.095 MPa vacuum, to obtain.

[0119] Example 3

[0120] The multiple synergistically reinforced polyurea elastomer material comprises:

[0121] The A component is selected from: isocyanate prepolymer with NCO content of 15.52%; the mass ratio of the A component to the B component is 1:1.08;

[0122] Component B formulation (100 parts): JEFFAMINE® D-2000: 36 parts; JEFFAMINE® T-5000: 5 parts; DETDA: 18 parts; APP-II: 14 parts; PA-MMT: 8 parts; MCA: 4 parts; f-GO: 1.5 parts; Aramid: 4 parts; Nano-SiC: 4 parts; self-healing amine: 7 parts; hydrophobic amine: 3.5 parts; additives: 4 parts.

[0123] The preparation steps are as follows:

[0124] Nano-predispersion: Take 10 parts of terminal amino polyether, add 1.5 parts of f-GO and 4 parts of Nano-SiC. Under cooling conditions, disperse using 800W ultrasonic waves for 30 minutes, with the material temperature controlled below 45℃, to obtain masterbatch.

[0125] Composite slurry dispersion: Mix the remaining 30 parts of amino-terminated polyether with the above masterbatch. Start high-speed dispersion at 2000 rpm, and add 14 parts of APP-II, 8 parts of PA-MMT, and 4 parts of MCA sequentially, dispersing for 20 minutes. Then reduce the speed to 1000 rpm, add 4 parts of Aramid fiber, and continue dispersing for 15 minutes. The final fineness was measured to be 55 μm.

[0126] Functional blending: Cool the slurry to 45°C. While stirring at a low speed of 400 rpm, add 7 parts of self-healing amine, 3.5 parts of hydrophobic amine, 18 parts of DETDA and 4 parts of additives in sequence, and mix for 15 minutes.

[0127] Degassing: Degas for 20 minutes under a vacuum of -0.095 MPa to obtain the product.

[0128] Example 4

[0129] Multiple synergistic reinforced polyurea elastomer materials, including:

[0130] Component A is selected as an isocyanate prepolymer with an NCO content of 14.53%; the mass ratio of component A to component B is 1:1.1.

[0131] Component B formulation (100 parts): JEFFAMINE® D-2000: 38 parts; JEFFAMINE® T-5000: 2 parts; DETDA: 16 parts; APP-II: 10 parts; PA-MMT: 5 parts; MCA: 2 parts; f-GO: 0.5 parts; Aramid: 2 parts; Nano-SiC: 2 parts; self-healing amine: 10 parts; hydrophobic amine: 5 parts; additives: 7.5 parts.

[0132] The preparation steps are as follows:

[0133] Nano-pre-dispersion: Take 10 parts of the terminal amino polyether, add 0.5 parts of f-GO and 2 parts of Nano-SiC. Under cooling conditions, use 600W ultrasonic dispersion for 20 minutes, and control the material temperature below 48°C to prepare the master batch.

[0134] Composite slurry dispersion: Mix the remaining 30 parts of the terminal amino polyether with the above master batch. Start high-speed dispersion at 1500 rpm, and then add 10 parts of APP-II, 5 parts of PA-MMT, 2 parts of MCA in sequence, and disperse for 20 minutes. Then, reduce the speed to 800 rpm, add 2 parts of Aramid fiber, and continue to disperse for 10 minutes. The final fineness is 60μm.

[0135] Functional blending: Cool the slurry to 45°C. Under low-speed stirring at 400 rpm, add 10 parts of self-repairing amine, 5 parts of hydrophobic amine, 16 parts of DETDA, and 7.5 parts of auxiliary agent in sequence, and mix for 25 minutes.

[0136] Defoaming: Defoam under -0.095 MPa vacuum for 20 minutes to obtain the product.

[0137] Example 5

[0138] The multi-synergistically enhanced polyurea elastomer material comprises:

[0139] The A component is selected from isocyanate prepolymers with an NCO content of 16.48%; the mass ratio of the A component to the B component is 1:1.06;

[0140] The B component formula (100 parts) is as follows: JEFFAMINE®D-2000: 26 parts; JEFFAMINE®T-5000: 9 parts; DETDA: 15 parts; APP-II: 18 parts; PA-MMT: 10 parts; MCA: 6 parts; f-GO: 3 parts; Aramid: 6 parts; Nano-SiC: 6 parts; self-repairing amine: 10 parts; hydrophobic amine: 5 parts; auxiliary agent: 6 parts.

[0141] The preparation steps are as follows:

[0142] Nano-pre-dispersion: Take 10 parts of the terminal amino polyether, add 3 parts of f-GO and 6 parts of Nano-SiC. Under cooling conditions, use 1000W ultrasonic dispersion for 40 minutes, and control the material temperature below 45°C to prepare the master batch.

[0143] Composite slurry dispersion: Mix the remaining 25 parts of the terminal amino polyether with the above master batch. Start high-speed dispersion at 2500 rpm, and then add 18 parts of APP-II, 10 parts of PA-MMT, 6 parts of MCA in sequence, and disperse for 30 minutes. Then, reduce the speed to 1200 rpm, add 6 parts of Aramid fiber, and continue to disperse for 20 minutes. The final fineness is 50μm.

[0144] Functional blending: Cool the slurry to 38°C. While stirring at a low speed of 500 rpm, add 10 parts of self-healing amine, 5 parts of hydrophobic amine, 15 parts of DETDA and 6 parts of additives in sequence, and mix for 25 minutes.

[0145] Degassing: Degas for 30 minutes under a vacuum of -0.098 MPa to obtain the product.

[0146] Comparative Example 1

[0147] The difference from Example 3 is that APP-II, PA-MMT, and MCA are not added; instead, 26 parts of inert talc are added.

[0148] Comparative Example 2

[0149] The difference from Example 3 is that PA-MMT and MCA are not added, and the amount of APP-II is increased to 26 parts.

[0150] Comparative Example 3

[0151] The difference from Example 3 is that f-GO is not added, and the amount of Aramid fiber is increased to 5.5 parts in order to maintain the total amount of filler.

[0152] Comparative Example 4

[0153] The difference from Example 3 is that Aramid fibers are not added, and the amount of f-GO is increased to 5.5 parts to maintain the total amount of filler.

[0154] Comparative Example 5

[0155] The difference from Example 3 is that Nano-SiC is not added, and 4 parts of talc are used instead to maintain the total amount of filler.

[0156] Comparative Example 6

[0157] The difference from Example 3 is that f-GO, Aramid, and Nano-SiC are not added; instead, 9.5 parts of talc are added.

[0158] Comparative Example 7

[0159] The difference from Example 3 is that no self-healing amine is added. In order to maintain the basic balance of amine equivalent, the amount of main resin is increased by 7 parts, namely JEFFAMINE® D-2000: 42 parts and JEFFAMINE® T-5000: 6 parts.

[0160] Comparative Example 8

[0161] The difference from Example 3 is that no hydrophobic amine is added, and the amount of main resin is increased by 3.5 parts, i.e. JEFFAMINE® D-2000: 39 parts; JEFFAMINE® T-5000: 5.5 parts.

[0162] Comparative Example 9

[0163] The difference from Example 3 is that no self-repairing amine and hydrophobic amine are added, and the amount of amino-terminated polyether is increased to 52.5 parts.

[0164] Comparative Example 10

[0165] The difference from Example 3 is that the B component is prepared by simply mixing 70 parts of JEFFAMINE® D-2000, 25 parts of DETDA, and 5 parts of auxiliary agent.

[0166] Comparative Example 11

[0167] The difference from Example 3 is that all raw materials are added at one time to a high-speed dispersion kettle, and after dispersion at 2000 rpm for 60 minutes, defoaming is performed.

[0168] Comparative Example 12

[0169] The difference from Example 3 is that f-GO and Nano-SiC are directly added to the dispersion together with other powders in Step 2.

[0170] Comparative Example 13

[0171] The difference from Example 3 is that an isocyanate prepolymer with an NCO content of 17.55% is selected for spraying.

[0172] Comparative Example 14

[0173] The difference from Example 3 is that an isocyanate prepolymer with an NCO content of 13.48% is selected for spraying.

[0174] Application Example 1

[0175] The polyurea material obtained in Example 3 is used as raw material.

[0176] Sample preparation:

[0177] Substrate: A 150 mm x 150 mm x 3 mm 6061-T6 aluminum alloy plate is selected as a simulation battery case material. After sandblasting (Sa2.5 level) and ethanol degreasing, the aluminum plate is sprayed with a layer of zinc-rich epoxy primer (dry film thickness 50 μm), and cured for 24 hours under standard environment. The polyurea material obtained in Example 3 is sprayed on the pretreated aluminum plate, and the final dry film thickness is strictly controlled to be 2.5 ± 0.1 mm. All samples are maintained at (23 ± 2) °C, (50 ± 5) % RH environment for 7 days.

[0178] Test setup: Fix the test panel horizontally on a support, coating side facing down. At the geometric center point of the back side (aluminum panel side) of the test panel, stick a K-type armored thermocouple probe using high-temperature thermal conductive glue, the probe tightly adheres to the aluminum panel surface. Connect the thermocouple to a multi-channel temperature data logger, set the sampling frequency to 1 Hz (1 time per second). Place a propane torch (flame temperature up to 1300℃) vertically below the test panel, adjust the height of the torch so that the tip of the blue flame core of the flame is 50 mm away from the coating surface. Place a fire baffle around the torch to reduce air flow disturbance.

[0179] Test execution: Turn on the temperature logger and record the initial back temperature. Light the torch and immediately start the timer, so that the flame continues to burn and stabilize the center point of the coating. Record the macroscopic phenomena such as burning, swelling, charring, dripping, and burning through of the coating by video recording. Continuously record the temperature change curve of the back side of the test panel.

[0180] Flame penetration time: the time from the start of burning to the first penetration of the flame through the coating, directly contacting the aluminum panel substrate. Determine by video playback and visual observation.

[0181] Thermal insulation failure time: the time from the start of burning to the temperature at the center point of the back side of the test panel reaching 250℃. 250℃ is an important reference critical temperature for the spread of thermal runaway of lithium batteries.

[0182] 10-minute back temperature: the temperature of the back side of the test panel at the 10th minute after the start of burning.

[0183] Residual carbon layer morphology: after the test, observe and record the thickness, density, strength and adhesion to the substrate of the residual carbon layer.

[0184] Application Example 2

[0185] The polyurea material obtained in Example 3 was used as raw material.

[0186] Test method:

[0187] Test panel preparation: Q235 cold-rolled steel plates with a size of 100 mm x 300 mm x 1 mm were selected and pre-treated with standard automotive electrophoretic coating (EDCoat) to simulate the real vehicle chassis. The polyurea material obtained in Example 3 was sprayed on the electrophoretic steel plate, and the final dry film thickness was strictly controlled at 2.5±0.2 mm. All test panels were cured for 7 days under standard conditions.

[0188] First stage: gravel impact test (refer to SAE J400 standard)

[0189] Equipment: Gravelometer gravel impact tester.

[0190] Test Conditions: The panels were tested immediately after being frozen in a -20°C freezer for 4 hours to simulate material brittleness in winter low temperature environments. The frozen panels were mounted in the test machine at a 45° angle. Using 80 psi (about 0.55 MPa) air pressure, 1 pint (about 550 g) of standard gravel was sprayed onto the panel surface in 10 seconds. After the test, the panel was allowed to return to room temperature, and the impact area was taped and quickly peeled with a standard high tack tape (3M 898) to remove all loose coating chips. The impact area was visually rated according to the number and size of chips, and the rating was referenced to the SAE J400 standard chart. The rating consisted of a number (damage density) and a letter (damage size). The smaller the number and the earlier the letter, the better the impact resistance.

[0191] Neutral Salt Spray Corrosion Test (Refer to ASTM B117 Standard)

[0192] Equipment: Neutral Salt Spray Test Chamber.

[0193] Procedure: The panels that passed the first stage impact test were hung in the salt spray chamber at a 20° angle from the vertical. A 5% NaCl solution was sprayed continuously at 35°C for a total of 500 hours of exposure.

[0194] Corrosion Rating: After 500 hours, the panels were removed and rinsed gently with flowing warm water and dried. The corrosion was evaluated using the method in accordance with ASTM D1654 standard:

[0195] Corrosion Spread Width of Scratched or Damaged Areas: The maximum one-sided distance of corrosion spread from the edge of the original damage was measured with a caliper.

[0196] Overall Corrosion Rating (ASTM D610): The percentage of red rust on the total area of the panel was evaluated, and a corresponding 10-point rating was given (10 = no rust, 0 = 100% rusted).

[0197] Application Comparative Example 1

[0198] The difference from Application Example 1 is that the polyurea material obtained in Comparative Example 6 was used as the raw material.

[0199] Application Comparative Example 2

[0200] The difference from Application Example 2 is that the polyurea material obtained in Comparative Example 4 was used as the raw material.

[0201] The test data of Examples 1-5 are shown in Table 2.

[0202] The test data of Comparative Examples 1-14 are shown in Table 3.

[0203] The test data of Application Example 1 and Application Comparative Example 1 are shown in Table 4.

[0204] The test data of application example 2 and application comparative example 2 are shown in Table 5.

[0205] Table 1: The ratio of each raw material of A component prepolymer and test results

[0206]

[0207] Table 2: Test data of examples 1-5

[0208]

[0209] Table 3: Test data of comparative examples 1-14

[0210]

[0211] From Tables 2-3, it can be seen that all five examples perform perfectly in the most core safety indicators, namely flame retardancy (V-0) and impact resistance (no cracking). This proves that the three synergistic systems constructed in the present application are stable, reliable and effective. By adjusting the ratio of each component, the performance can be focused. For example, examples 2 and 5 show higher strength and wear resistance when the content of the reinforcing and flame-retardant components is higher; while example 4 has top-notch self-repairing and hydrophobic properties when the content of the intelligent protection component is higher. Example 3 represents the best balance point of each performance, which is the best combination of comprehensive performance and cost.

[0212] Comparative Example 1 was completely non-flame retardant, while Comparative Example 2, using a higher amount of a single flame retardant, was far less effective than Example 3. This irrefutably demonstrates the decisive role of the "phosphorus-nitrogen-silicon" synergy in forming a high-quality, high-strength char layer. Comparative Examples 3, 4, and 5 each removed a "component" from the reinforcing system, resulting in significant performance shortcomings: without f-GO, the interface weakened, leading to decreased impact resistance; without aramid, macroscopic toughness was lost, resulting in severe cracking under impact; and without SiC, wear resistance deteriorated drastically. Comparative Example 6, by completely removing the reinforcing system, almost completely collapsed its physical protection capability. This proves that nano-, micro-, and hard particles are indispensable, collectively forming a "joint defense" against damage at different scales. The results of Comparative Examples 7 and 8 are simple and direct: without self-healing amines, there is no self-healing function; without hydrophobic amines, there is no superhydrophobic surface. Comparative Example 9 simultaneously lost both of these "value-added" functions. This proves that the intelligent characteristics of this invention originate entirely from the introduction of specific functional molecules. Comparative Example 10 represents basic pure polyurea. Compared to Example 3, it shows orders of magnitude difference in all core safety protection indicators, including flame retardancy, impact resistance, abrasion resistance, and water resistance. This visually demonstrates the revolutionary progress of this invention compared to traditional technologies. Comparative Example 11 uses the most primitive one-step mixing method. Even with the correct formulation, the performance of the final product completely collapses, with a 33% decrease in strength, an 18% decrease in elongation, and a 2.6-fold difference in abrasion resistance, proving the absolute necessity of a multi-step dispersion process. Although Comparative Example 12 uses a multi-step method, it neglects the specialized pretreatment of nanomaterials, resulting in the nano-effects not being fully utilized, and its performance is still far inferior to Example 3. This proves that the refined preparation method including nano-pre-dispersion defined in this invention is the guarantee for achieving high performance. Comparative Examples 13 and 14 use the exact same component B as Example 3, except that the NCO content of component A deviates from the range defined in this invention. The results show that excessive NCO leads to an overly hard and brittle material that cracks upon impact; excessive NCO leads to an overly soft and weak material, resulting in a significant decrease in strength and abrasion resistance. These two failed cases "outside the boundary" powerfully demonstrate, from the opposite perspective, that the 14.5%-16.5% NCO content range proposed in this invention is the optimal window for achieving a balance between the rigidity and toughness of the material.

[0213] Table 4: Test data for Application Example 1 and Application Comparative Example 1

[0214]

[0215] As shown in Table 4, the application comparative example 1 has the same flame retardant formulation as the application example 1, but its thermal insulation failure time and flame penetration time are only half of the application example 1. The main reason is that it lacks the reinforcing components such as f-GO and aramid fiber, and the expanded carbon layer formed loses the "steel framework", and the mechanical strength decreases significantly, which cannot resist the physical erosion of the flame for a long time, and cracks and peels prematurely, resulting in heat and flame breaking through in advance.

[0216] Table 5: Test data of application example 2 and application comparative example 2

[0217]

[0218] As shown in Table 5, the application comparative example 2 uses the material formula derived from comparative example 4, and its core defect is the lack of aramid fiber as a macroscopic reinforcing framework. Although the tensile strength is not low from the laboratory data, the elongation at break decreases significantly, and the overall toughness of the material is insufficient. This performance shortcoming is sharply magnified in the harsh low-temperature chip impact application: the impact resistance rating of application comparative example 2 is much lower than that of application example 2, and the coating presents typical brittle tearing and peeling, losing the complete protection of the underlying substrate. These impact damage points become the breakthrough point for subsequent salt spray corrosion, resulting in a much lower final corrosion protection rating than application example 2. This strongly proves the integrity of the "nano-micro" multi-scale reinforcing system in the present application, and the irreplaceability of the micro-scale high-toughness fiber for resisting macroscopic physical damage and ensuring the protection performance throughout the life cycle.

Claims

1. A multi-synergistic reinforced polyurea elastomer material, characterized in that, It is prepared by reacting component A and component B, wherein the mass ratio of component A to component B is 1:(1.05-1.12). Component A is an isocyanate prepolymer with an NCO content between 14.5% and 16.5%. Component B is a mixture of composite functional amines, comprising 100 parts by weight of the main resin and amine chain extender, and includes: a. A phosphorus-nitrogen-silicon synergistic flame retardant system, wherein the dosage is 23.5-68 parts; b. A nano-micro multi-scale reinforcement system, wherein the dosage is 5.7-30 parts; c. An intelligent protection system, the dosage of which is 8-30 parts; d. An adjuvant, used in amounts of 3-12 parts; The phosphorus-nitrogen-silicon synergistic flame retardant system comprises: 14-36 parts of ammonium polyphosphate, 7-20 parts of phosphorus-modified layered silicate, and 2.5-12 parts of nitrogen-based flame retardant; The phosphorus-modified layered silicate is phytic acid-modified montmorillonite; The nano-micro multi-scale reinforcement system comprises: 0.7-6 parts of carbon-based nanomaterials, 2.5-12 parts of high-toughness microfibers, and 2.5-12 parts of high-hardness nanoparticles. The carbon-based nanomaterial is a functionalized graphene oxide, the high-toughness microfiber is an aramid fiber, and the high-hardness nanoparticles are nano-silicon carbide. The intelligent protection system comprises: 5.5-20 parts of a diamine containing reversible dynamic chemical bonds, and 2.5-10 parts of a functional amine containing fluorinated silane groups; The main resin is an amino-terminated polyether, and the amine chain extender is an aromatic diamine chain extender; the additives consist of silane coupling agents, dispersants, defoamers, and pigments. The preparation method of the aforementioned multi-synergistic reinforced polyurea elastomer material includes the following steps: (1) Nano pre-dispersion step: The nanomaterials in the nano-micro multi-scale reinforcement system are mixed with a portion of the main resin, and ultrasonic dispersion treatment with a power of not less than 600W is performed under the condition that the material temperature is lower than 50℃, or high-energy ball milling treatment is performed to prepare nano composite masterbatch. (2) Composite slurry preparation steps: Mix the nanocomposite masterbatch with the remaining main resin, then add the raw materials of the phosphorus-nitrogen-silicon synergistic flame retardant system and the micron fibers in the nano-micron multi-scale reinforcement system, and perform high-speed shear dispersion at a rotation speed of 1500-2500 rpm until the slurry fineness is no greater than 60 μm; (3) Functional blending step: After cooling the slurry obtained in step (2) to below 45°C, add the amine chain extender and the raw materials and additives of the intelligent protection system in sequence, and stir at low speed at 300-500 rpm to mix evenly. (4) Degassing step: The final mixture obtained in step (3) is subjected to vacuum degassing treatment under a vacuum degree of not less than -0.09MPa.

2. A method for preparing the multi-synergistic reinforced polyurea elastomer material according to claim 1, characterized in that, Includes the following steps: (1) Nano pre-dispersion step: The nanomaterials in the nano-micro multi-scale reinforcement system are mixed with a portion of the main resin, and ultrasonic dispersion treatment with a power of not less than 600W is performed under the condition that the material temperature is lower than 50℃, or high-energy ball milling treatment is performed to prepare nano composite masterbatch. (2) Composite slurry preparation steps: Mix the nanocomposite masterbatch with the remaining main resin, then add the raw materials of the phosphorus-nitrogen-silicon synergistic flame retardant system and the micron fibers in the nano-micron multi-scale reinforcement system, and perform high-speed shear dispersion at a rotation speed of 1500-2500 rpm until the slurry fineness is no greater than 60 μm; (3) Functional blending step: After cooling the slurry obtained in step (2) to below 45°C, add the amine chain extender and the raw materials and additives of the intelligent protection system in sequence, and stir at low speed at 300-500 rpm to mix evenly. (4) Degassing step: The final mixture obtained in step (3) is subjected to vacuum degassing treatment under a vacuum degree of not less than -0.09MPa.

3. An application of the multi-synergistic reinforced polyurea elastomer material according to claim 1, characterized in that, Safety protection for battery pack housings, chassis, or high-voltage components in new energy vehicles.

4. The application of the multi-synergistic reinforced polyurea elastomer material according to claim 3, characterized in that, The aforementioned safety protection involves applying a protective coating made of the polyurea elastomer material to the surface of the battery pack casing, chassis, or high-voltage components. The thickness of the protective coating is 2.0-3.0 mm.

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