A bonding adhesive for aramid bulletproof material, a preparation method thereof and application thereof

Abstract

This application discloses an adhesive for aramid bulletproof materials, its preparation method, and its application. The adhesive for aramid bulletproof materials includes component A and component B. By total weight percentage, component A includes 4-6.5% acrylic resin, 5-7.5% blocked isocyanate, 1.2-1.5% silane solvent, and 1.8-2.0% wetting agent; component B includes 15-18% waterborne polyurethane, 8-10% epoxy resin, 1.0-2.0% epoxy resin solvent, 1.6-2.4% organosilicon crosslinking agent, 0.2-0.4% zinc catalyst, 0.12-0.25% epoxy resin curing agent, and 0.4-0.6% additives. The balance is deionized water. When using, component A and component B are mixed at a mass ratio of 1:(1-1.2). This invention solves the problem that existing adhesives for aramid bulletproof materials are difficult to achieve simultaneously with high toughness, high strength, and excellent interfacial stability.

Description

Technical Field

[0001] This application relates to aramid bulletproof materials, and more particularly to an adhesive for aramid bulletproof materials, its preparation method, and its application. Background Technology

[0002] Aramid fibers, due to their extremely high specific strength, specific modulus, and excellent energy absorption characteristics, are widely used in the preparation of lightweight, high-performance bulletproof materials. In the preparation of aramid bulletproof nonwoven fabrics or composite materials, the adhesives bonding the fiber layers are not only crucial for fixing fiber orientation and forming a stable preform, but also directly affect the transmission of stress waves, energy dissipation, and whether catastrophic delamination failure occurs when the material is subjected to ballistic impact. Therefore, the quality of the adhesive directly determines the protection level and reliability of the final bulletproof product.

[0003] Existing adhesives used in aramid bulletproof materials are divided into rigid resin-based adhesives (such as epoxy resin systems) and more flexible adhesives (such as polyurethane systems). While rigid resin-based adhesives offer high bond strength, the cured adhesive layer is brittle and prone to cracking and rapid propagation under high-speed impact, resulting in poor delamination resistance and insufficient overall material toughness. More flexible adhesives, while providing good toughness and impact resistance, often have lower cohesive strength and heat resistance, making them susceptible to creep or strength decay under long-term use or high-temperature environments. They cannot provide sufficient rigid support for high-strength aramid fibers, leading to a decline in the material's macroscopic mechanical properties. Therefore, it is difficult to simultaneously achieve high toughness, high strength, and excellent interfacial stability.

[0004] However, compound formulations often fail to achieve synergistic performance enhancement due to compatibility issues between different resin systems, conflicting curing mechanisms, or mismatched process windows. Instead, they may lead to system instability or a decline in overall performance.

[0005] Therefore, the development of specialized adhesives that endow aramid bulletproof materials with high toughness and strength and can form an excellent and stable interface bond with aramid fibers is of great significance for improving the overall performance and reliability of bulletproof materials. Summary of the Invention

[0006] To address the problem that existing adhesives for aramid bulletproof materials cannot simultaneously achieve high toughness, high strength, and excellent interfacial stability, this paper provides an adhesive for aramid bulletproof materials, its preparation method, and its application.

[0007] The first inventive objective of this invention is achieved through the following technical solution: An adhesive for bonding aramid bulletproof materials comprises component A and component B, and its composition, based on the total weight percentage of components A and B, is as follows. Component A includes: Acrylic resin 4-6.5%, Blocked isocyanates 5-7.5%, Silane solvent 1.2-1.5%, Wetting agent 1.6-2.0%, Component B includes Waterborne polyurethane 15-18%, Epoxy resin 8-10%, Epoxy resin solvent 1.0-2.0%, Organosilicon crosslinking agent 1.6-2.4%, Zinc catalyst 0.2-0.4%, The curing agent for epoxy resin is 0.12-0.25%. Additives 0.4-0.6%, The remaining amount is deionized water. The additive is a composition of liquid silicone rubber, polyimide and zinc oxide in a mass ratio of (2-3):1:2.

[0008] By adopting the above technical solution, the adhesive for aramid bulletproof material of this application constructs a composite adhesive layer with high strength, high toughness and excellent interface stability on the surface and between layers of aramid fibers through physical impregnation, chemical bonding and stepwise curing. Component A, the acrylic resin, provides immediate initial tack to ensure process operability; the blocked isocyanate acts as a latent crosslinking agent, unblocking and releasing highly active isocyanate groups in subsequent processes; the silane solvent functions as both a solvent and a coupling agent, and its hydrolyzable alkoxy groups pre-act with the fiber surface to enhance interfacial bonding. Component B is the main film-forming and curing component. Its waterborne polyurethane forms a flexible skeleton, while epoxy resin serves as a rigid skeleton. The organosilicon crosslinking agent can condense with the active groups on the fiber surface and within the system to form a Si-O-Si or Si-OC covalent network. The zinc catalyst can effectively catalyze the reaction of isocyanate with hydroxyl / amino groups and the condensation of silanes. The additives, composed of liquid silicone rubber, polyimide, and zinc oxide in a specific ratio, can synergistically enhance toughness, heat resistance, and catalytic activity. The application process involves three sequential stages: mixing and impregnation, drying and preliminary curing, and hot pressing for shaping. During the mixing and impregnation stage, after the mixture of components A and B, it is impregnated with aramid fibers. The acrylic resin and wetting agent rapidly improve the wetting and spreading of the colloid on the hydrophobic aramid fibers, and the silane component begins to undergo preliminary adsorption and hydrolysis with the fiber surface. During the drying and initial curing stage, moisture evaporates, the activity of the zinc catalyst is enhanced, promoting partial silane condensation, while the blocked isocyanate is unblocked and undergoes initial cross-linking with the active hydrogen and epoxy curing agent on the polyurethane chain to form an initial network. During the hot pressing and setting stage, the epoxy resin and curing agent react completely to form a dense, rigid three-dimensional network. The unsealed isocyanate further crosslinks with polyurethane and epoxy segments, while the organosilicon network thoroughly forms a network structure with both strength and toughness. Therefore, the adhesive for aramid bulletproof materials of this application integrates the toughness of waterborne polyurethane, the strength of epoxy resin and the interfacial bonding ability of organosilicon into a single waterborne system through a stepwise curing mechanism. The optimized combination of additives and catalyst system improves the overall performance of the adhesive layer, making it particularly suitable for reliable bonding of high modulus and low surface energy materials such as para-aramid fibers. This ultimately significantly enhanced the interlayer bonding performance and overall ballistic performance of the aramid bulletproof nonwoven fabric.

[0009] Optional: The zinc catalyst is zinc acetylacetonate.

[0010] By adopting the above technical solution, using zinc acetylacetonate as a catalyst, the central zinc ion of zinc acetylacetonate can selectively and reversibly coordinate with isocyanates (unblocked products from the blocked isocyanates of component A), active hydrogen groups (such as -OH, -NH2) in polyurethane prepolymers, and silanols, hydrolysis products of organosilicon crosslinking agents. This significantly reduces the activation energy of related polycondensation and addition crosslinking reactions. Furthermore, its β-diketone (acetylacetonate) ligand structure not only gives it good solubility and dispersibility in an aqueous environment, avoiding system flocculation or drastic pH fluctuations that may be caused by inorganic zinc salts, but also allows for the regulation of the electron density of zinc ions through the ligand field effect, thereby finely adjusting its catalytic activity and achieving optimized control of the reaction rate. In the initial stage after the adhesive is mixed, zinc acetylacetonate begins to catalyze the hydrolysis and preliminary condensation of organosilanes, promoting their pre-bonding to the surface of aramid fibers. In the subsequent drying and hot pressing stages, as the temperature rises, it efficiently catalyzes the addition polymerization reaction between the unsealed isocyanate groups and the active hydrogen compounds contained in polyurethane, epoxy resin curing agents, etc., while continuing to catalyze the condensation between silanols to form a Si-O-Si network. This ensures that the rigid epoxy network, flexible polyurethane phase, and interfacial silane coupling layer can synchronously and coordinately form a dense interpenetrating network structure, avoiding stress concentration or local defects caused by excessive differences in crosslinking reaction rates, thereby improving the bonding performance of adhesive layers in aramid bulletproof materials.

[0011] Optional: The epoxy resin curing agent is a composition of room temperature epoxy curing agent, medium temperature epoxy curing agent, and high temperature epoxy curing agent in a mass ratio of 1:2:(1-4).

[0012] By adopting the above technical solution, a composite curing system is formed by using room temperature, medium temperature and high temperature epoxy curing agents in a specific mass ratio of 1:2:(1-4) to conduct gradient temperature triggering control and staged curing of epoxy resin ring-opening addition reaction. Room temperature curing agents can react rapidly with epoxy groups at ambient temperature, providing the necessary initial gel strength and process operation window; The medium-temperature curing agent is activated within the drying temperature range of 80-120℃ and undertakes the main task of curing and cross-linking. The high-temperature curing agent fully exerts its activity at the hot-pressing temperature of 125-140℃, achieving the final deep curing and performance enhancement of the epoxy network; The three curing agents work synergistically to ensure that the crosslinking density and network structure of the epoxy resin gradually and orderly increase with the increase of the process temperature. This ensures that the curing reaction rate of the epoxy resin is highly synchronized with the process steps, so that the adhesive is in the most suitable curing state at each processing stage. Ultimately, this allows the aramid bulletproof nonwoven fabric to obtain the best and most stable interlayer bonding strength, anti-delamination ability and overall mechanical properties.

[0013] Optional: The silane solvent is trichloropropyltriethoxysilane.

[0014] By adopting the above technical solution, trichloropropyltriethoxysilane has the dual functions of solvent and reactive silane coupling agent. Its ethoxy group can be hydrolyzed in an aqueous environment to generate highly reactive silanol, which can be adsorbed on the surface of aramid fiber through hydrogen bonding. In the subsequent drying and hot pressing process, it can form a strong Si-O-Si covalent bond network with a very small amount of hydroxyl groups on the fiber surface or by condensation with itself, thereby building a strong chemical bridge between the fiber and the resin matrix. Meanwhile, the propyl chloride of trichloropropyltriethoxysilane can exhibit good compatibility or undergo secondary reactions with other resin components in the adhesive system (such as epoxy resin and polyurethane), thereby enhancing the internal bonding strength and density of the overall adhesive layer. The problem of effective wetting of aramid fibers, interfacial chemical modification and cohesive reinforcement was solved, and the interfacial bonding strength and hydrolytic aging resistance between the adhesive and aramid were improved.

[0015] Optionally, the organosilicon crosslinking agent is one of trichloropropyltriethoxysilane or triaminosilane.

[0016] By adopting the above technical solution, the organosilicon crosslinking agent is trichloropropyltriethoxysilane or triaminosilane. These two multifunctional silanes can build a high-strength and durable Si-O-Si covalent network inside the adhesive and between various interfaces. Trichloropropyltriethoxysilane generates silanols through its hydrolyzable ethoxy groups. These silanols can condense with each other or with the silanols on the fiber surface and in silane solvents to form a three-dimensional siloxane network. Its chloropropyl groups provide potential reaction sites or physical entanglement points with organic resin phases. Triaminosilanes, through their multiple amino functional groups, can directly chemically crosslink with epoxy groups in epoxy resins, isocyanate groups or carboxyl groups in polyurethane prepolymers, and can also undergo silanol condensation through their alkoxy groups, thereby achieving chemical interpenetration and tight bonding between organic resin networks and inorganic siloxane networks. These two options ensure the formation of a high-density, high-stability chemical bonding network between the aramid fiber and the resin matrix, as well as within the resin matrix. This greatly improves the crosslinking density, cohesive strength, heat resistance, and hydrolysis resistance of the adhesive layer, enabling the bulletproof material to maintain excellent interlayer bonding performance and long-term reliability even in harsh environments.

[0017] The preparation method of the adhesive for the above-mentioned aramid bulletproof material includes the following steps: Acrylic resin, blocked isocyanate, silane solvent and wetting agent are mixed and stirred evenly to obtain component A; A first mixture is formed by mixing waterborne polyurethane, epoxy resin, epoxy resin solvent, silicone crosslinking agent, zinc catalyst, additives, and a portion of deionized water. The remaining deionized water is then mixed with the waterborne polyurethane to form a second mixture. The first mixture is then added to the second mixture under stirring conditions, and the mixture is stirred to obtain component B.

[0018] By adopting the above technical solution, component A is pre-mixed evenly, so that acrylic resin and blocked isocyanate can achieve molecular-level uniform mixing and initial swelling in silane solvent. At the same time, the wetting agent is fully dispersed, laying the foundation for subsequent uniform mixing and interfacial interaction with component B. This process avoids premature deblocking of isocyanate that may be caused by high temperature. Component B was prepared using a two-step method: first, solid-liquid premixing, then high-speed emulsification. First, all solid and liquid components, except for some deionized water and waterborne polyurethane, are premixed at low speed for a long time. This step ensures the uniform distribution of key additives such as zinc catalyst and organosilicon crosslinking agent in the system and initiates the initial compatibility and pre-reaction of epoxy resin with curing agent and silane. Subsequently, the first mixture was injected into the waterborne polyurethane premixed with the remaining deionized water under high-speed shear conditions, which enabled the components in the first mixture to be rapidly and uniformly dispersed and emulsified into the waterborne polyurethane emulsion, forming a colloidal dispersion system with fine particle size, uniform distribution and stable storage, effectively preventing component segregation, gelation or demulsification caused by improper feeding sequence or mixing. This ensures that the final A and B components are uniform and stable, and can precisely trigger a series of chemical reactions according to the design mechanism when mixed, thereby reliably achieving the predetermined high-performance indicators of the adhesive.

[0019] The application of adhesives for aramid bulletproof materials in the preparation of aramid bulletproof nonwoven fabrics is illustrated in the following steps: Mix component A and component B and stir evenly to obtain an adhesive for aramid bulletproof material. Para-aramid fibers are laid out, and the laid para-aramid fibers are then passed through a traction adhesive tank. At the same time, aramid bulletproof material is transported into the adhesive tank with adhesive and compounded with para-aramid fibers at 35-40℃. The glued para-aramid fiber layer is then compounded with a polyethylene film to obtain a unidirectional nonwoven fabric. Dry the unidirectional nonwoven fabric at a temperature of 120-135℃ for 15-20 minutes, and then roll it up. After cutting the obtained unidirectional nonwoven fabric, it is stacked at 0° / 90° and then pressed and cured at 125-140℃ to prepare aramid bulletproof nonwoven fabric.

[0020] By adopting the above technical solution, the high-performance two-component adhesive of this application is applied to the preparation of aramid bulletproof nonwoven fabric, resulting in aramid bulletproof nonwoven fabric with high specific strength, excellent anti-delamination properties and ballistic performance.

[0021] Optional: After the para-aramid fibers were laid, and before they were bonded to the aramid bulletproof material with adhesive, acid washing and alkaline washing were also performed. Pickling treatment: Immerse the laid para-aramid fibers in a dilute acid solution at 25-50℃ for 5-20 minutes, and then rinse with deionized water until neutral; Alkaline washing treatment: The acid-washed para-aramid fibers are immersed in an alkaline washing agent for 5-10 minutes, then rinsed with deionized water until neutral and dried. The alkaline adhesive cleaning agent, by weight percentage, comprises 3-6% acrylic resin, 1-2.5% phthalate, 0.5-2% sodium hydroxide or calcium chloride, and the balance being deionized water.

[0022] By adopting the above technical solution, a two-step pretreatment process of acid washing and alkaline washing is used to deeply physical clean and chemically activate the fiber surface before aramid fiber impregnation and lamination. Pickling can effectively remove organic pollutants, weak boundary layers and some amorphous regions on the surface of aramid fibers during production and transportation. It can also slightly etch the fiber surface to increase its roughness and specific surface area. At the same time, it may introduce a small amount of polar functional groups such as carboxyl groups at the ends of the fiber molecular chains, which can significantly improve the surface energy. The acrylic resin and phthalate in the alkaline adhesive washing treatment agent can form an extremely thin and uniform pre-coating or transition layer on the activated fiber surface. This layer has excellent compatibility and affinity with the acrylic resin and polyurethane components in the subsequent main adhesive. At the same time, the sodium hydroxide or calcium chloride in the treatment agent can neutralize the residual acid and may promote the formation of ionic or coordinate bonds between the fiber surface and the pre-treatment agent, thereby constructing a strong and tough interface layer with a continuous gradient of chemical composition and transition of mechanical properties between the fiber and the main adhesive layer. This two-step synergistic fiber surface pretreatment adds a "molecular-level double-sided adhesive" layer between the aramid fiber and the high-performance adhesive matrix. This significantly alleviates stress concentration that might be caused by excessive modulus difference between the aramid fiber and the high-performance adhesive matrix, ensuring that impact loads can be effectively transferred and dispersed to the high-strength fiber through this interface layer. This improves interlayer bonding, prevents delamination failure of the bulletproof material under impact, and ultimately enhances the energy absorption efficiency and structural reliability of the final product.

[0023] In summary, this application has at least the following beneficial effects: 1. By innovatively integrating the toughness of waterborne polyurethane, the strength of epoxy resin, and the interfacial bonding ability of organosilicon into a waterborne system, the contradiction between the poor environmental performance of traditional solvent-based adhesives and the difficulty of a single resin system to simultaneously meet the multiple requirements of bulletproof materials for interlayer toughness, peel strength, and environmental aging resistance is solved. 2. By using a combination of closed isocyanate and epoxy curing agents in specific ratios (room temperature, medium temperature, and high temperature), precise staged control of the curing reaction is achieved, ensuring the feasibility and stability of the continuous production process from impregnation and drying to hot pressing, and avoiding problems such as premature curing or incomplete curing. 3. By selecting specific catalysts such as zinc acetylacetonate and specialized additives composed of liquid silicone rubber, polyimide, and zinc oxide, the curing process and overall performance of the adhesive layer were further synergistically optimized. Specific silane solvents and crosslinking agents (such as trichloropropyltriethoxysilane) enhanced the interfacial bonding with aramid fibers. The accompanying fiber pickling and alkaline adhesive washing pretreatment processes further significantly enhanced the interfacial bond strength and durability between the adhesive and the high-modulus, low-surface-energy aramid fibers. Detailed Implementation

[0025] The acrylic resin is BASF's transparent acrylic polymer emulsion Acronal® 5411; Blocked isocyanate, Wanhua Chemical's HTBL-275MS product; Waterborne polyurethane, Lamborghini waterborne polyurethane 1526; The epoxy resin is a liquid bisphenol A type epoxy resin, a commercially available product with an epoxy equivalent of 192 g / eq and a viscosity (25°C) of 11000 mPa·s. Liquid silicone rubber, specifically Wacker Elastosil® LR 3003 / 10 TR A / B; Polyimide, processed into powder using DuPont Vespel® PI TP-8005, with a particle size of 0.2μm; Para-aramid fiber, a commercially available product, has a linear density of 930 dtex, a tensile strength of 3245 MPa, a tensile modulus of 124 GPa, an elongation at break of 2.9%, and a density of 1.44 g / cm³. 2 ; Trichloropropyltriethoxysilane, CAS 5089-70-3, commercially available product; Chloropropyltrimethoxysilane, CAS 2530-87-2, commercially available product; Methyltrimethoxysilane, CAS 1185-55-3, commercially available product; N-β-aminoethyl-γ-aminopropyltrimethoxysilane, CAS 1760-24-3, commercially available product; Octylphenol polyoxyethylene ether, commercially available product OP-10; Butylene glycol diglycidyl ether, diethylenetriamine, 2-methylimidazole, diaminodiphenylmethane, sodium hydroxide, and calcium chloride are all commercially available analytical grade products. Zinc acetylacetone, organotin catalyst DBTDL, and zinc octoate are commercially available products with a purity greater than 98 wt%. 100nm zinc oxide whiskers are commercially available products; Zinc oxide is in powder form with a particle size of 500 nm; Dilute sulfuric acid is prepared by diluting commercially available concentrated sulfuric acid. Diisononyl phthalate, a commercially available product with a purity greater than 95 wt%.

[0026] Example 1 An adhesive for bonding aramid bulletproof materials is a two-component system consisting of component A and component B. Based on the total weight of components A and B being 100%, its specific composition is as follows: Component A consists of 6.0% acrylic resin, 7.0% blocked isocyanate, 1.4% silane solvent, and 1.8% wetting agent; Component B consists of 17.5% waterborne polyurethane, 9.1% epoxy resin, 1.7% epoxy resin solvent, 2.2% organosilicon crosslinking agent, 0.38% zinc catalyst, 0.23% epoxy resin curing agent, 0.5% additives, and the balance being deionized water.

[0027] The silane solvent is trichloropropyltriethoxysilane, the wetting agent is octylphenol polyoxyethylene ether OP-10, the epoxy resin solvent is butanediol diglycidyl ether, the organosilicon crosslinking agent is trichloropropyltriethoxysilane, and the zinc catalyst is zinc acetylacetonate.

[0028] The epoxy resin curing agent is a composition of room temperature epoxy curing agent, medium temperature epoxy curing agent, and high temperature epoxy curing agent in a mass ratio of 1:2:3. The room temperature epoxy curing agent is diethylenetriamine, the medium temperature epoxy curing agent is 2-methylimidazole, and the high temperature epoxy curing agent is diaminodiphenylmethane.

[0029] The additive is a composition of liquid silicone rubber, polyimide and zinc oxide in a mass ratio of 2.8:1:2.

[0030] The preparation method of the adhesive for the aramid bulletproof material in this embodiment is as follows: Preparation of component A: Add 6.0 kg of acrylic resin, 7.0 kg of blocked isocyanate, 1.4 kg of trichloropropyltriethoxysilane and 1.8 kg of wetting agent to a reaction vessel, and stir for 50 min at 30℃ and 600 rpm to ensure thorough mixing and obtain homogeneous component A for later use.

[0031] Preparation of component B: 10.0 kg of waterborne polyurethane, 9.1 kg of epoxy resin, 1.7 kg of epoxy resin solvent, 2.2 kg of trichloropropyltriethoxysilane, 0.38 kg of zinc acetylacetonate, 0.23 kg of additives and 20.0 kg of deionized water were mixed and stirred for 30 min at 30 °C and 350 rpm to form the first mixture. 32.19 kg of deionized water and 7.5 kg of waterborne polyurethane were mixed in another container and stirred evenly at 30°C to form a second mixture. Under high-speed shearing conditions at 2200 rpm, the first mixture is slowly added to the second mixture prepared in step b. After the addition is complete, the mixture is stirred at 2200 rpm for 80 minutes at 30°C to ensure that the components are fully emulsified and evenly dispersed, resulting in a uniform and stable component B for later use.

[0032] Component A and component B are stored separately and then mixed together before use.

[0033] Comparative Example 1 An adhesive for bonding aramid bulletproof materials differs from Example 1 in its specific composition as follows: Component A consists of 7.0% blocked isocyanate, 1.4% silane solvent, and 1.8% wetting agent; Component B consists of 17.5% waterborne polyurethane, 9.1% epoxy resin, 1.7% epoxy resin solvent, 2.2% organosilicon crosslinking agent, 0.38% zinc catalyst, 0.23% epoxy resin curing agent, 0.5% additives, and the balance being deionized water.

[0034] In the preparation method, the amount of acrylic resin used when preparing component A is 0 kg.

[0035] Comparative Example 2 An adhesive for bonding aramid bulletproof materials differs from Example 1 in its specific composition as follows: Component A consists of 6.0% acrylic resin, 7.0% blocked isocyanate, and 1.8% wetting agent; Component B consists of 17.5% waterborne polyurethane, 9.1% epoxy resin, 1.7% epoxy resin solvent, 2.2% organosilicon crosslinking agent, 0.38% zinc catalyst, 0.23% epoxy resin curing agent, 0.5% additives, and the balance being deionized water.

[0036] In the preparation method, the amount of silane solvent used when preparing component A is 0 kg.

[0037] Comparative Example 3 An adhesive for bonding aramid bulletproof materials differs from Example 1 in its specific composition as follows: Component A consists of 6.0% acrylic resin, 7.0% blocked isocyanate, and 1.8% wetting agent; Component B consists of 17.5% waterborne polyurethane, 9.1% epoxy resin, 1.7% epoxy resin solvent, 2.2% organosilicon crosslinking agent, 0.38% zinc catalyst, 0.23% epoxy resin curing agent, and the balance being deionized water.

[0038] In the preparation method, the amount of silicon additive used when preparing component B is 0 kg.

[0039] Comparative Example 4 An adhesive for bonding aramid bulletproof materials differs from Example 1 in that it uses an organotin catalyst, such as DBTDL, instead of a zinc catalyst.

[0040] Example 2 An adhesive for bonding aramid bulletproof materials differs from Example 1 in that it uses zinc octoate instead of zinc acetylacetonate by mass.

[0041] Comparative Example 5 An adhesive for bonding aramid bulletproof materials differs from Example 1 in that it uses an equal mass of 100nm zinc oxide whiskers instead of zinc acetylacetonate.

[0042] Comparative Example 6 An adhesive for bonding aramid bulletproof materials differs from Example 1 in that the epoxy resin curing agent is a single component and is diethylenetriamine.

[0043] Example 3 An adhesive for bonding aramid bulletproof materials differs from Example 1 in that the epoxy resin curing agent is a single component and is 2-methylimidazole.

[0044] Comparative Example 7 An adhesive for bonding aramid bulletproof materials differs from Example 1 in that the epoxy resin curing agent is a single component and is diaminodiphenylmethane.

[0045] Example 4 An adhesive for bonding aramid bulletproof materials, which differs from Example 1 in that the silane solvent is chloropropyltrimethoxysilane.

[0046] Example 5 An adhesive for bonding aramid bulletproof materials, which differs from Example 1 in that the silane solvent is methyltrimethoxysilane.

[0047] Example 6 An adhesive for bonding aramid bulletproof materials, which differs from Example 1 in that the organosilicon crosslinking agent is N-β-aminoethyl-γ-aminopropyltrimethoxysilane.

[0048] Example 7 An adhesive for bonding aramid bulletproof materials, which differs from Example 1 in that the organosilicon crosslinking agent is methyltrimethoxysilane.

[0049] Example 8 An adhesive for bonding aramid bulletproof materials differs from Example 1 in its preparation method, as detailed below: Preparation of component A: Add 6.0 kg of acrylic resin, 7.0 kg of blocked isocyanate, 1.4 kg of trichloropropyltriethoxysilane and 1.8 kg of wetting agent to a reaction vessel, and stir for 50 min at 30℃ and 600 rpm to ensure thorough mixing and obtain homogeneous component A for later use.

[0050] Preparation of component B: 17.5 kg of waterborne polyurethane, 9.1 kg of epoxy resin, 1.7 kg of epoxy resin solvent, 2.2 kg of trichloropropyltriethoxysilane, 0.38 kg of zinc acetylacetone, 0.23 kg of additives, and 52.19 kg of deionized water were mixed and stirred at 30°C and 350 rpm for 30 min, and then stirred at 2200 rpm for 80 min to obtain component B, which was set aside for later use.

[0051] Example 9 An adhesive for bonding aramid bulletproof materials is a two-component system consisting of component A and component B. The specific composition, based on the total weight of components A and B being 100%, is as follows: Component A consists of 4.0% acrylic resin, 5% blocked isocyanate, 1.5% silane solvent, and 1.8% wetting agent; Component B consists of 18% waterborne polyurethane, 10% epoxy resin, 2% epoxy resin solvent, 2.4% organosilicon crosslinking agent, 0.4% zinc catalyst, 0.25% epoxy resin curing agent, 0.4% additives, and the balance being deionized water.

[0052] The silane solvent is trichloropropyltriethoxysilane, the organosilicon crosslinking agent is trichloropropyltriethoxysilane, and the zinc catalyst is zinc acetylacetonate.

[0053] The epoxy resin curing agent is a composition of room temperature epoxy curing agent, medium temperature epoxy curing agent, and high temperature epoxy curing agent in a mass ratio of 1:2:4. The room temperature epoxy curing agent is diethylenetriamine, the medium temperature epoxy curing agent is 2-methylimidazole, and the high temperature epoxy curing agent is diaminodiphenylmethane.

[0054] The additive is a composition of liquid silicone rubber, polyimide and zinc oxide in a mass ratio of 3:1:2.

[0055] Example 10 An adhesive for bonding aramid bulletproof materials is a two-component system consisting of component A and component B. The specific composition, based on the total weight of components A and B being 100%, is as follows: Component A consists of 6.5% acrylic resin, 7.5% blocked isocyanate, 1.4% silane solvent, and 2.0% wetting agent; Component B consists of 15% waterborne polyurethane, 8.0% epoxy resin, 1.0% epoxy resin solvent, 1.6% organosilicon crosslinking agent, 0.2% zinc catalyst, 0.12% epoxy resin curing agent, 0.6% additives, and the balance being deionized water.

[0056] The silane solvent is trichloropropyltriethoxysilane, the organosilicon crosslinking agent is trichloropropyltriethoxysilane, and the zinc catalyst is zinc acetylacetonate.

[0057] The epoxy resin curing agent is a composition of room temperature epoxy curing agent, medium temperature epoxy curing agent, and high temperature epoxy curing agent in a mass ratio of 1:2:1. The room temperature epoxy curing agent is diethylenetriamine, the medium temperature epoxy curing agent is 2-methylimidazole, and the high temperature epoxy curing agent is diaminodiphenylmethane.

[0058] The additive is a composition of liquid silicone rubber, polyimide and zinc oxide in a mass ratio of 2:1:2.

[0059] Example 11 The application of adhesives for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials.

[0060] The specific steps are as follows: Components A and B were mixed and stirred for 20 minutes at 30°C and 400 rpm to prepare an aqueous polyurethane colloid, which was then stored at 20°C for later use. The para-aramid fibers were laid out, and the laid para-aramid fibers were then subjected to acid washing and alkaline washing treatments in sequence. Pickling treatment: The laid para-aramid fibers are immersed in a 5% (w / w) dilute sulfuric acid solution at 30°C for 10 minutes, and then rinsed with deionized water until neutral. Alkaline washing treatment: The acid-washed para-aramid fibers are immersed in an alkaline washing agent for 8 minutes, then rinsed with deionized water until neutral and dried. The alkaline washing agent consists of 5% acrylic resin, 2.1% phthalate, 1% sodium hydroxide, 1% calcium chloride, and the remainder is deionized water. The para-aramid fibers, after two treatments, were drawn through a glue bath at 35°C. Simultaneously, the prepared waterborne polyurethane colloid was fed into the glue bath and compounded with the para-aramid fibers. Then, the glued para-aramid fiber layer was compounded with a polyethylene film to prepare a unidirectional nonwoven fabric. The mass percentages of para-aramid fibers, glued amount, and polyethylene film in the unidirectional nonwoven fabric were 78%, 16%, and 6%, respectively, with a tolerance of ±5%. The obtained unidirectional nonwoven fabric was dried at 120℃ for 20 minutes, and then wound up. After cutting the obtained unidirectional nonwoven fabric, it was stacked at 0° / 90° cross-over with a stacking density of 146±4 g / m². 2 60t / m of material is subjected to hot pressing at 140℃. 2 Aramid bulletproof nonwoven fabric was prepared by pressure setting and curing.

[0061] Components A and B were prepared in Example 1.

[0062] Comparative Example 8 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Comparative Example 1.

[0063] Comparative Example 9 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Comparative Example 2.

[0064] Comparative Example 10 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Comparative Example 3.

[0065] Comparative Example 11 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Comparative Example 4.

[0066] Example 12 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Example 2.

[0067] Comparative Example 12 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Comparative Example 5.

[0068] Comparative Example 13 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Comparative Example 6.

[0069] Example 13 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Example 3.

[0070] Comparative Example 14 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Comparative Example 7.

[0071] Example 14 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Example 4.

[0072] Example 15 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Example 5.

[0073] Example 16 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Example 6.

[0074] Example 17 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Example 7.

[0075] Example 18 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Example 8.

[0076] Example 19 The application of adhesives for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials.

[0077] The specific steps are as follows: Components A and B were mixed and stirred for 20 minutes at 30°C and 400 rpm to prepare an aqueous polyurethane colloid, which was then stored at 20°C for later use. Laying para-aramid fibers; Para-aramid fibers were drawn through a glue bath at 35°C, while a prepared waterborne polyurethane colloid was simultaneously fed into the glue bath and compounded with the para-aramid fibers. The glued para-aramid fiber layer was then compounded with a polyethylene film to prepare a unidirectional nonwoven fabric. The mass percentages of para-aramid fibers, glued amount, and polyethylene film in the unidirectional nonwoven fabric were 78%, 16%, and 6%, respectively, with a tolerance of ±5%. The obtained unidirectional nonwoven fabric was dried at 120℃ for 20 minutes, and then wound up. After cutting the obtained unidirectional nonwoven fabric, it was stacked at 0° / 90° cross-over with a stacking density of 146±4 g / m². 2 60t / m of material is subjected to hot pressing at 140℃. 2 Aramid bulletproof nonwoven fabric was prepared by pressure setting and curing.

[0078] Components A and B were prepared in Example 1.

[0079] Example 20 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that the alkaline washing agent consists of 5% acrylic resin, 2.1% phthalate, and the remainder is deionized water.

[0080] Example 21 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that the alkaline washing agent consists of 5% acrylic resin, 1% sodium hydroxide, 1% calcium chloride, and the remainder is deionized water.

[0081] Example 22 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that the alkaline washing agent consists of 2.1% phthalate, 1% sodium hydroxide, 1% calcium chloride, and the balance is deionized water.

[0082] Example 23 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Example 10.

[0083] Example 24 The application of adhesive for bonding aramid bulletproof materials is used to bond aramid fibers to form aramid bulletproof materials. The difference from Example 11 is that components A and B are prepared in Example 11.

[0084] The aramid bulletproof materials obtained in Examples 12-24 and Comparative Examples 8-14 were subjected to interlaminar shear strength, peel strength, tensile properties, bending properties, ballistic limits, and post-ballistic impact damage morphology observation and testing. The test results are shown in the table below.

[0085] Table 1. Test results of interlaminar shear strength and peel strength

[0086] Table 2. Test results of tensile and flexural properties

[0087] Table 3. Results of Observation and Testing of Ballistic Limits and Damage Morphology After Ballistic Impact

[0088] Compared with Comparative Examples 8-11, the interlaminar shear strength, peel strength, tensile strength, tensile modulus, flexural strength, and flexural modulus of Example 12 are significantly greater than those of Comparative Examples 8-11, and the V50 ballistic limit of Example 11 is greater than that of Comparative Examples 8-11.

[0089] Therefore, the adhesive for the aramid bulletproof material of this application is a two-component water-based system. The application process involves three orderly stages: mixing and impregnation, drying and initial curing, and hot-pressing. Through physical wetting, chemical bonding, and stepwise curing, a composite adhesive layer with high strength, high toughness, and excellent interfacial stability is constructed on the surface and between the aramid fibers. Component A, acrylic resin, provides immediate initial tack to ensure processability. The silane solvent functions as both a solvent and a coupling agent; its hydrolyzable alkoxy groups pre-act with the fiber surface, enhancing interfacial bonding. The closed-type isocyanate... Cyanate esters act as latent crosslinking agents, unblocking and releasing highly active isocyanate groups in subsequent processes. Component B is the main film-forming and curing component, with its waterborne polyurethane forming a flexible framework and epoxy resin as a rigid framework. The organosilicon crosslinking agent can condense with active groups on the fiber surface and within the system to form a Si-O-Si or Si-OC covalent network. In addition, the zinc catalyst can effectively catalyze the reaction of isocyanate with hydroxyl / amino groups and silane condensation, while the additives composed of liquid silicone rubber, polyimide, and zinc oxide in a specific ratio can synergistically enhance toughness, heat resistance, and catalytic activity. In the three stages: During the mixing and impregnation stage, after components A and B are mixed, the acrylic resin and wetting agent rapidly improve the wetting and spreading of the colloid on the hydrophobic aramid fiber, and the silane component begins to undergo preliminary adsorption and hydrolysis with the fiber surface. During the drying and initial curing stage, moisture evaporates, the activity of the zinc catalyst is enhanced, promoting partial silane condensation, while the blocked isocyanate is unblocked and undergoes initial cross-linking with the active hydrogen and epoxy curing agent on the polyurethane chain to form an initial network. During the hot pressing and setting stage, under high temperature and high pressure, the epoxy resin and curing agent react completely to form a dense, rigid three-dimensional network. The unsealed isocyanate further crosslinks with polyurethane and epoxy segments, while the organosilicon network thoroughly forms a network structure with both strength and toughness. Therefore, the adhesive for aramid bulletproof materials of this application integrates the toughness of waterborne polyurethane, the strength of epoxy resin, and the interfacial bonding ability of organosilicon into a single waterborne system through a stepwise curing mechanism. The optimized compatibility of additives and catalysts improves the overall performance of the adhesive layer, making it particularly suitable for reliable bonding of high-modulus, low-surface-energy materials such as para-aramid fibers. This ultimately significantly enhances the interlayer bonding performance and overall bulletproof performance of aramid bulletproof nonwoven fabric.

[0090] Compared with Example 11, Example 12 and Comparative Example 12, the interlaminar shear strength, peel strength, tensile strength, tensile modulus, flexural strength and flexural modulus of Example 11 and Example 12 are greater than those of Comparative Example 12, and the V50 ballistic limit of Example 11 and Example 12 is greater than that of Comparative Example 12.

[0091] Furthermore, the interlaminar shear strength, peel strength, tensile strength, tensile modulus, flexural strength, and flexural modulus of Example 11 are greater than those of Example 12, and the V50 ballistic limit of Example 11 is greater than that of Example 12.

[0092] Therefore, in this application, an organic zinc catalyst is selected as the zinc catalyst, which avoids the problems of uneven dispersion and easy sedimentation of inorganic zinc oxide catalysts in adhesives, resulting in uneven and insufficient catalytic performance. Furthermore, zinc acetylacetonate is selected as the zinc catalyst, which has better performance in adhesives.

[0093] The central zinc ion of zinc acetylacetonate can selectively and reversibly coordinate with isocyanates (unblocked products from component A blocked isocyanates), active hydrogen groups (such as -OH, -NH2) in polyurethane prepolymers, and silanols, hydrolysis products of organosilicon crosslinking agents, significantly reducing the activation energy of related polycondensation and addition crosslinking reactions. Furthermore, its β-diketone (acetylacetonate) ligand structure not only provides excellent solubility and dispersibility in aqueous environments, avoiding flocculation or drastic pH fluctuations that may be caused by inorganic zinc salts, but also allows for precise regulation of the electron density of zinc ions through ligand field effects, thereby achieving optimized control of the reaction rate. In adhesive mixing... Initially, zinc acetylacetonate catalyzes the hydrolysis and preliminary condensation of organosilanes, promoting their pre-bonding to the surface of aramid fibers. In the subsequent drying and hot-pressing stages, as the temperature rises, it efficiently catalyzes the addition polymerization reaction between the unsealed isocyanate groups and the active hydrogen compounds contained in polyurethane, epoxy resin curing agents, etc., while continuing to catalyze the condensation between silanols to form a Si-O-Si network. This ensures that the rigid epoxy network, the flexible polyurethane phase, and the interfacial silane coupling layer can synchronously and coordinately form a dense interpenetrating network structure, avoiding stress concentration or local defects caused by excessive differences in crosslinking reaction rates, thereby improving the bonding performance of adhesive layers for aramid bulletproof materials.

[0094] Compared with Examples 11, 13, 13, and 14, Examples 11 and 13 have greater interlaminar shear strength, peel strength, tensile strength, tensile modulus, flexural strength, and flexural modulus than Examples 13 and 14. Examples 11 and 13 also have greater V50 ballistic limit than Examples 13 and 14.

[0095] Furthermore, the interlaminar shear strength, peel strength, tensile strength, tensile modulus, flexural strength, and flexural modulus of Example 11 are greater than those of Example 13, and the V50 ballistic limit of Example 11 is greater than that of Example 13.

[0096] Therefore, the selection of epoxy resin curing agents in this application needs to be matched with the preparation process of aramid fiber bulletproof materials, especially their drying and heat curing temperature parameters. A single room-temperature curing agent cures too early and cannot meet the curing requirements of subsequent hot pressing, resulting in the adhesive layer strength and fiber compaction density failing to meet expectations. A single high-temperature curing agent cures too late in the process, resulting in insufficient bonding strength between the adhesive and the fiber surface in the early stages, which cannot be effectively compensated for after curing during subsequent hot pressing, thus causing the interlayer bond strength to fail to meet expectations. Therefore, Comparative Examples 13 and 14 failed to achieve the strength of Examples 11 and 13.

[0097] Example 13 uses a medium-temperature curing agent, whose curing temperature is between the other two, and it has a certain compatibility with the process, but it is not as good as the compound curing agent used in Example 11.

[0098] The adhesive used in Example 11 comprises a composite curing system of room temperature, medium temperature, and high temperature epoxy curing agents in a specific mass ratio of 1:2:(1-4). This system allows for gradient temperature triggering and staged curing of the epoxy resin ring-opening addition reaction. The room temperature curing agent reacts rapidly with epoxy groups at ambient temperature, providing the necessary initial gel strength and process operation window. The medium temperature curing agent is activated within the drying temperature range of 80-120°C, undertaking the main curing and crosslinking tasks. The high temperature curing agent fully utilizes its activity at the hot pressing and setting temperature of 125-140°C, achieving the final deep curing and performance enhancement of the epoxy network. Through synergistic proportioning, the crosslinking density and network structure of the epoxy resin gradually and orderly increase with the increase of the process temperature, ensuring that the curing reaction rate of the epoxy resin is highly synchronized with the process steps. This ensures that the adhesive is in the most suitable curing state at each processing stage, ultimately enabling the aramid bulletproof nonwoven fabric to obtain optimal and stable interlayer bonding strength, anti-delamination ability, and overall mechanical properties.

[0099] Comparing Examples 11, 14, and 15, Examples 11 and 14 have greater interlaminar shear strength, peel strength, tensile strength, tensile modulus, flexural strength, and flexural modulus than Example 15, and their V50 ballistic limit is greater than that of Example 15. Example 11 has greater interlaminar shear strength, peel strength, tensile strength, tensile modulus, flexural strength, and flexural modulus than Example 14, and its V50 ballistic limit is greater than that of Example 14.

[0100] Therefore, this application uses trichloropropyltriethoxysilane as a silane solvent, which has the dual functions of solvent and reactive silane coupling agent. Its ethoxy group can be hydrolyzed in an aqueous environment to generate highly reactive silanol, which can be adsorbed onto the surface of aramid fiber through hydrogen bonding. During subsequent drying and hot pressing, it can form a strong Si-O-Si covalent network with a very small number of hydroxyl groups on the fiber surface or by self-condensation, thereby constructing a strong chemical bridge between the fiber and the resin matrix. At the same time, the propyl chloride of trichloropropyltriethoxysilane can produce good compatibility or undergo secondary reactions with other resin components in the adhesive system (such as epoxy resin and polyurethane), enhancing the internal bonding force and density of the overall adhesive layer. This solves the problems of effective wetting of aramid fiber, interfacial chemical modification and cohesive reinforcement, and improves the interfacial bonding strength and hydrolytic aging resistance between the adhesive and aramid.

[0101] Comparing Examples 11 and 16-17, Examples 12 and 16 exhibit greater interlaminar shear strength, peel strength, tensile strength, tensile modulus, flexural strength, and flexural modulus than Example 17, with Example 11 being the optimal example. Examples 11 and 16 also show greater V50 ballistic limits than Example 17, with Example 11 being the optimal example. Therefore, in this application, the organosilicon crosslinking agent is preferably one of trichloropropyltriethoxysilane or triaminosilane. These two multifunctional silanes can construct a high-strength, durable Si-O-Si covalent network within the adhesive and between interfaces, ensuring the formation of a high-density, high-stability chemical bonding network between the aramid fiber and the resin matrix, as well as within the resin matrix. This significantly improves the crosslinking density, cohesive strength, heat resistance, and hydrolysis resistance of the adhesive layer, enabling the bulletproof material to maintain excellent interlaminar bonding performance and long-term reliability even in harsh environments.

[0102] Comparing Examples 11 and 18, the interlaminar shear strength, peel strength, tensile strength, tensile modulus, flexural strength, and flexural modulus of Example 11 are greater than those of Example 18; the V50 ballistic limit of Example 11 is greater than that of Example 18. Therefore, the two-step method of "premixing solid and liquid first, then emulsifying at high speed" for the preparation of component B in this application is superior. The resulting components A and B are uniform and stable, and can precisely trigger a series of chemical reactions according to the design mechanism when used in combination, thereby reliably achieving the predetermined high-performance indicators of the adhesive.

[0103] Comparing Examples 11 and 19-22, the interlaminar shear strength, peel strength, tensile strength, tensile modulus, flexural strength, and flexural modulus of Examples 20-22 are greater than those of Example 19; the V50 ballistic limit of Examples 20-22 is greater than that of Example 19; the interlaminar shear strength, peel strength, tensile strength, tensile modulus, flexural strength, and flexural modulus of Example 11 are greater than those of Examples 20-22; and the V50 ballistic limit of Example 11 is greater than that of Examples 20-22.

[0104] Therefore, this application employs a two-step pretreatment process—acid washing and alkaline washing—before impregnating and laminating aramid fibers to deeply physical clean and chemically activate the fiber surface. Acid washing effectively removes organic contaminants, weak boundary layers, and some amorphous regions adhering to the surface of the aramid fibers during production and transportation. It also slightly etches the fiber surface to increase its roughness and specific surface area, and may introduce a small amount of polar functional groups such as carboxyl groups at the ends of the fiber molecular chains, significantly enhancing surface energy. The acrylic resin and phthalate in the alkaline washing agent form an extremely thin and uniform pre-coating or transition layer on the activated fiber surface. This layer interacts with the acrylic resin in the subsequent main adhesive. The aramid and polyurethane components exhibit excellent compatibility and affinity. Simultaneously, the sodium hydroxide or calcium chloride in the pretreatment agent neutralizes residual acid and may promote the formation of ionic or coordinate bonds between the fiber surface and the pretreatment agent, thereby constructing a strong and tough interface layer with a continuous chemical composition gradient and transitional mechanical properties between the fiber and the main adhesive layer. This two-step synergistic fiber surface pretreatment adds a "molecular-level double-sided adhesive" layer between the aramid fiber and the high-performance adhesive matrix, greatly alleviating stress concentration that may be caused by excessive modulus difference between the aramid fiber and the high-performance adhesive matrix. This ensures that impact loads can be effectively transferred and dispersed to the high-strength fiber through this interface layer. This improves interlayer bonding, prevents delamination failure of the bulletproof material under impact, and ultimately enhances the energy absorption efficiency and structural reliability of the final product.

[0105] As can be seen from Examples 23-24, the performance achieved in Examples 23-24 is similar to that in Example 11. Therefore, the adhesive for aramid bulletproof materials in this application, based on the total weight percentage of components A and B, comprises: component A including 4-6.5% acrylic resin, 5-7.5% blocked isocyanate, 1.2-1.5% silane solvent, and 2.0% wetting agent; component B including 15-18% waterborne polyurethane, 8-10% epoxy resin, 1.0-2.0% epoxy resin solvent, 1.6-2.4% organosilicon crosslinking agent, 0.2-0.4% zinc catalyst, 0.12-0.25% epoxy resin curing agent, and 0.4-0.6% additives. The remaining balance of the adhesive for aramid bulletproof materials is deionized water. It is preferable to mix them at a mass ratio of 1:(1-1.2) when using them.

[0106] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of protection claimed by the present invention, they are protected by patent law.

Claims

1. An adhesive for bonding aramid bulletproof materials, characterized in that, Comprising components A and B, its composition, based on the total weight percentage of components A and B, is as follows: Component A includes: Acrylic resin 4-6.5%, Blocked isocyanates 5-7.5%, Silane solvent 1.2-1.5%, Wetting agent 1.6-2.0%, Component B includes Waterborne polyurethane 15-18%, Epoxy resin 8-10%, Epoxy resin solvent 1.0-2.0%, Organosilicon crosslinking agent 1.6-2.4%, Zinc catalyst 0.2-0.4%, The curing agent for epoxy resin is 0.12-0.25%. Additives 0.4-0.6%, The remaining amount is deionized water. The additive is a composition of liquid silicone rubber, polyimide and zinc oxide in a mass ratio of (2-3):1:

2.

2. The adhesive for bonding aramid bulletproof materials according to claim 1, characterized in that, The zinc catalyst is zinc acetylacetonate.

3. The adhesive for bonding aramid bulletproof materials according to claim 1, characterized in that, The epoxy resin curing agent is a composition of room temperature epoxy curing agent, medium temperature epoxy curing agent and high temperature epoxy curing agent with a mass ratio of 1:2:(1-4).

4. The adhesive for bonding aramid bulletproof materials according to claim 1, characterized in that, The silane solvent is trichloropropyltriethoxysilane.

5. The adhesive for bonding aramid bulletproof materials according to claim 1, characterized in that, The organosilicon crosslinking agent is one of trichloropropyltriethoxysilane or triaminosilane.

6. A method for preparing the adhesive for aramid bulletproof material according to any one of claims 1-5, characterized in that, Includes the following steps: Acrylic resin, blocked isocyanate, silane solvent and wetting agent are mixed and stirred evenly to obtain component A; A first mixture is formed by mixing waterborne polyurethane, epoxy resin, epoxy resin solvent, silicone crosslinking agent, zinc catalyst, additives, and a portion of deionized water. The remaining deionized water is then mixed with the waterborne polyurethane to form a second mixture. The first mixture is then added to the second mixture under stirring conditions, and the mixture is stirred to obtain component B.

7. The application of the adhesive for aramid bulletproof materials according to any one of claims 1-5 in the preparation of aramid bulletproof nonwoven fabric, characterized in that, The specific steps are as follows: Mix component A and component B and stir evenly to obtain an adhesive for aramid bulletproof material. Para-aramid fibers are laid out, and the laid para-aramid fibers are then passed through a traction adhesive tank. At the same time, aramid bulletproof material is transported into the adhesive tank with adhesive and compounded with para-aramid fibers at 35-40℃. The glued para-aramid fiber layer is then compounded with a polyethylene film to obtain a unidirectional nonwoven fabric. Dry the unidirectional nonwoven fabric at a temperature of 120-135℃ for 15-20 minutes, and then roll it up. After cutting the obtained unidirectional nonwoven fabric, it is stacked at 0° / 90° and then pressed and cured at 125-140℃ to prepare aramid bulletproof nonwoven fabric.

8. The application of the adhesive for aramid bulletproof materials according to claim 7 in the preparation of aramid bulletproof nonwoven fabric, characterized in that, After the para-aramid fibers were laid, and before they were bonded to the aramid bulletproof material with adhesive, they were subjected to acid washing and alkaline washing. Pickling treatment: Immerse the laid para-aramid fibers in a dilute acid solution at 25-50℃ for 5-20 minutes, and then rinse with deionized water until neutral; Alkaline washing treatment: The acid-washed para-aramid fibers are immersed in an alkaline washing agent for 5-10 minutes, then rinsed with deionized water until neutral and dried. The alkaline adhesive cleaning agent, by weight percentage, comprises 3-6% acrylic resin, 1-2.5% phthalate, 0.5-2% sodium hydroxide or calcium chloride, and the balance being deionized water.

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