Quick-hardening high-strength adhesive for sticking rock wool-based composite board outer wall and preparation method of quick-hardening high-strength adhesive

Abstract

The invention relates to the technical field of building materials, in particular to a quick-hardening and high-strength adhesive for pasting a rock wool-based composite board outer wall and a preparation method of the quick-hardening and high-strength adhesive. The adhesive comprises a component A and a component B. The component A is prepared from 40-50 parts of E44 epoxy resin, 25-30 parts of polyurethane prepolymer, 10-15 parts of quartz powder, 5-10 parts of calcium carbonate, 0.5-1 part of wood fiber, 1-2 parts of silane coupling agent and 0.1-0.5 part of defoaming agent. And the component B comprises the following components in parts by weight: 6-8 parts of a polyamide curing agent and 0.5-1 part of DMP-30. Through cooperation of the polyamide curing agent and the DMP-30, the reaction of an epoxy group and amine hydrogen is accelerated, and the gelation time is shortened; meanwhile, the E44 epoxy resin and the polyurethane prepolymer are matched, the impact strength is improved through a sea-island structure, and brittle cracking of a rock wool interface is avoided; in addition, the polyurethane prepolymer and the E44 epoxy resin react to release heat, the initial temperature of the system is increased, and epoxy curing is accelerated; according to the present invention, the multiple components are matched with one another, and the prepared adhesive can achieve the effects of rapid hardening and high strength maintaining when the adhesive is used for pasting the rock wool-based composite board outer wall.

Description

Technical Field

[0001] This application relates to the field of building materials technology, specifically to a fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls and its preparation method. Background Technology

[0002] Rock wool is made primarily from high-quality basalt and dolomite. After melting at temperatures above 1450℃, it is centrifuged into fibers using an internationally advanced four-axis centrifuge. Simultaneously, a certain amount of binder, dust-proofing oil, and water-repellent agent are sprayed in. The fibers are then collected by a wool collector, processed using a pendulum method, and then laid in a three-dimensional manner before curing and cutting to create rock wool products of various specifications and applications. Rock wool is widely used as a thermal insulation material in the construction and industrial sectors.

[0003] Rock wool-based composite panels have a large surface area, and traditional adhesives lack sufficient bonding strength, making them prone to detachment due to gravity or wind pressure (especially in high-rise buildings). Exterior wall installation requires a suitable environment (temperature > 5℃, no rain), and rapid curing can reduce the impact of sudden weather changes, thereby increasing the daily installation volume. Therefore, it is essential to develop a fast-curing, high-strength adhesive suitable for bonding rock wool-based composite panels to exterior walls. Summary of the Invention

[0004] To address the issue of rapid curing and high bonding strength of adhesives when bonding rock wool-based composite panels to exterior walls, this application provides a fast-curing, high-strength adhesive for bonding rock wool-based composite panels to exterior walls.

[0005] In a first aspect, this application provides a fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls, employing the following technical solution: A fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls, comprising component A and component B, wherein component A and component B comprise the following components in parts by weight: Component A: 40-50 parts E44 epoxy resin, 25-30 parts polyurethane prepolymer, 10-15 parts quartz powder, 5-10 parts calcium carbonate, 0.5-1 part wood fiber, 1-2 parts silane coupling agent, and 0.1-0.5 parts defoamer. Component B: 6-8 parts polyamide curing agent, 0.5-1 part DMP-30.

[0006] By adopting the above technical solution, the polyamide curing agent, as the main curing agent, provides a flexible long-chain structure, reducing the crosslinking brittleness of the epoxy resin. Simultaneously, its active amine groups undergo a ring-opening reaction with the epoxy groups, achieving medium-speed curing. The DMP-30 accelerator, as a tertiary amine catalyst, accelerates the reaction between the epoxy groups and amine hydrogen, shortening the gel time.

[0007] E44 epoxy resin provides a rigid framework and high adhesion, forming a dense cross-linked network after curing, giving the base strength. The polyurethane prepolymer introduces flexible segments, dispersing stress through an "island structure," improving impact strength and preventing brittle cracking at the rock wool interface. Furthermore, the polyurethane prepolymer contains -NCO groups, which can react with the -OH groups of the epoxy resin to form an oxazolidinone structure. This reaction is significantly exothermic, increasing the initial temperature of the system and accelerating epoxy curing.

[0008] The low-viscosity resin system (E44 epoxy resin + polyurethane prepolymer) can penetrate into the porous structure of rock wool, forming a "riveted" mechanical interlocking after curing. Breakage at the bonding interface requires overcoming the mechanical anchoring force. The polyurethane segments and epoxy combine rigidity and flexibility, making the thermal expansion coefficient of the adhesive layer close to that of rock wool, thus avoiding the risk of debonding due to temperature differences.

[0009] This application utilizes a combination of polyamide curing agent and DMP-30 to accelerate the reaction between epoxy groups and amine hydrogen, shortening the gel time. Simultaneously, the combination of E44 epoxy resin and polyurethane prepolymer disperses stress through a "sea-island structure," enhancing impact strength and preventing brittle cracking at the rock wool interface. Furthermore, the significant exothermic reaction between the polyurethane prepolymer and E44 epoxy resin raises the initial temperature of the system, accelerating epoxy curing. The synergistic effect of these multiple components results in an adhesive that, when used for bonding rock wool-based composite panels to exterior walls, achieves rapid hardening while maintaining high strength.

[0010] Preferably, component B further includes a curing aid, which includes at least one of 2-ethyl-4-methylimidazol, zinc acetylacetonate, and 4-hydroxymethylbenzyl alcohol.

[0011] By employing the above technical solution, 2-ethyl-4-methylimidazolium, as an anionic catalyst, utilizes the nucleophilic attack of the tertiary nitrogen atom on its imidazolium ring on the epoxy group to generate an oxygen anion active center, triggering a chain self-polymerization reaction of the epoxy group (forming an ether bond network). This process does not consume the imidazolium itself, achieving highly efficient cyclic catalysis.

[0012] Zinc acetylacetonate, as a Lewis acid, coordinates its zinc ions with the oxygen atoms of the epoxy group, polarizing the CO bond, lowering the ring-opening energy barrier, and accelerating the nucleophilic attack of the polyamide curing agent. The primary hydroxyl group (-CH2OH) of 4-hydroxymethylbenzyl alcohol undergoes an etherification reaction with the epoxy group, and the released active hydrogen can assist the crosslinking of the polyamide curing agent, shortening the induction period.

[0013] In addition, 2-ethyl-4-methylimidazolium can significantly reduce the decomposition temperature of latent curing agents such as dicyandiamide and catalyze the esterification reaction of acid anhydrides, thereby reducing curing time. Zinc acetylacetonate forms a transition state complex with polyamide curing agents through ligand exchange, enhancing the nucleophilicity of the amine groups.

[0014] Preferably, the curing aid is a dual-curing composition of 2-ethyl-4-methylimidazole and zinc acetylacetonate.

[0015] By employing the above technical solution, the imidazole ring of 2-ethyl-4-methylimidazolium contains two nitrogen atoms (tertiary nitrogen at position 1 and secondary nitrogen at position 3). The tertiary nitrogen exhibits strong nucleophilicity, directly attacking the epoxy group to open the ring and form an oxygen anion active center. The lone pair electrons of the secondary nitrogen can coordinate with zinc ions, enhancing Lewis acid activity. The steric hindrance effect of the ethyl at position 2 and the methyl at position 4 reduces intermolecular aggregation, improves dispersibility in the resin, and prevents the active sites from being obscured.

[0016] Preferably, the mass ratio of 2-ethyl-4-methylimidazolium to zinc acetylacetonate in the dual-curing composition is 2:0.8-1.2.

[0017] By adopting the above technical solution, when the mass ratio of zinc acetylacetonate is too low, its Lewis acid activation ability is insufficient to effectively reduce the ring-opening energy barrier of the epoxy group, resulting in a slow reaction initiation. The absence of zinc acetylacetonate weakens its stabilizing effect on the oxygen anion intermediate catalyzed by 2-ethyl-4-methylimidazole, leading to premature termination of some chain growth; when the mass ratio of zinc acetylacetonate is too high, Lewis acid overload occurs, the catalytic pathway is unbalanced, and excess zinc acetylacetonate over-polarizes the epoxy group, but insufficient 2-ethyl-4-methylimidazole leads to low anion chain growth efficiency, and the synergistic effect of the two is broken; when zinc acetylacetonate is in excess, its ligand acetylacetone residues act as plasticizers, interfering with the densification of the crosslinked network; therefore, after extensive research and experimental verification, the applicant finally determined that the mass ratio of 2-ethyl-4-methylimidazole to zinc acetylacetonate in the dual-curing composition of this application is preferably as described above.

[0018] Preferably, the curing aid is a three-curing composition of 2-ethyl-4-methylimidazole, zinc acetylacetonate, and 4-hydroxymethylbenzyl alcohol.

[0019] By employing the above technical solution, the tertiary amine nitrogen atom (N3) in the 2-ethyl-4-methylimidazol molecule acts as a strong nucleophilic center, directly attacking the epoxy group to open the ring and generate an alkoxy anion, initiating anionic polymerization chain reaction. The zinc ion of zinc acetylacetonate coordinates with the oxygen atom of the epoxy group, polarizing the CO bond, lowering the ring-opening energy barrier, and significantly increasing the reaction rate at low temperatures. The primary hydroxyl group of 4-hydroxymethylbenzyl alcohol acts as a proton donor, promoting the protonation of the alkoxy anion and accelerating chain propagation; the benzene ring structure enhances compatibility with epoxy resins, while hydrogen bonding prevents the precipitation or aggregation of zinc acetylacetonate.

[0020] Preferably, component A further includes a reinforcing agent, which includes at least one of nano-silica, CTBN toughening agent, and zirconium oxide.

[0021] By employing the above technical solutions, nano-silica and silane coupling agents form Si-O-Si covalent bonds through the hydrolytic condensation of surface silanol groups and the alkoxy groups of the silane coupling agent, enhancing interfacial adhesion. Nano-silica and polyurethane prepolymer form physical crosslinking points through hydrogen bonding with the urethane groups of polyurethane, improving initial tack. Nano-silica and DMP-30 are linked through surface hydroxyl adsorption of DMP-30, enriching amine catalytic active centers and accelerating epoxy ring-opening. Nano-silica can form a three-dimensional hydrogen bond network (shear-thinning properties), preventing adhesive sagging during vertical wall application, ensuring effective contact area, and shortening surface drying time. Nano-silica has a high specific surface area, providing more reaction sites and reducing gel time.

[0022] CTBN toughening agent reacts with epoxy resin to form ester bonds through the pre-reaction of terminal carboxyl groups and epoxy groups, reducing system viscosity and promoting molecular diffusion. CTBN toughening agent interacts with polyamide curing agents through the interpenetration of flexible segments with long polyamide chains, slowing phase separation and forming a more uniform "island structure." Localized stress deformation is converted into heat energy, promoting cross-linking in surrounding areas. CTBN toughening agent interacts with wood fibers through a rubber phase encapsulation of the wood fibers, reducing interfacial defects caused by fiber moisture absorption. The flexible segments of CTBN toughening agent dilute the resin system, reducing viscosity and accelerating the diffusion of the polyamide curing agent to the epoxy groups.

[0023] Zirconia, together with quartz powder / calcium carbonate, forms a heat-conducting network with inorganic fillers through its high thermal conductivity, accelerating the diffusion of reaction heat. In adhesive applications, zirconia particles embed themselves within the pores of rock wool fibers, enhancing mechanical interlocking and chemical bonding. Furthermore, zirconia's higher thermal conductivity than the resin matrix allows for rapid dissipation of reaction heat, preventing curing stagnation caused by localized overheating.

[0024] Preferably, the reinforcing agent is a dual-reinforcing composition of nano-silica and CTBN toughening agent.

[0025] By employing the above technical solution, the terminal carboxyl groups of CTBN pre-react with the epoxy groups of the epoxy resin, precipitating out "island structures" during the curing process. These structures act as stress concentration points, inducing crazes and shear bands to absorb impact energy. The flexible segments of CTBN reduce the system viscosity and promote the diffusion of the polyamide curing agent. Nano-silica fills the micron-level gaps between the CTBN islands, forming a "rigid particle-flexible matrix" composite structure. This structure prevents crack propagation through crack pinning effect, thereby improving tensile strength.

[0026] The flexible chains of CTBN slow down molecular motion and prolong gel time; while the silanol groups enriched on the surface of nano-silica adsorb the DMP-30 accelerator, forming localized high-concentration catalytic centers that accelerate the epoxy ring-opening reaction. Nano-silica has a significantly higher thermal conductivity than the resin matrix, allowing for rapid dissipation of localized heat released during the CTBN phase transition, preventing uneven curing due to localized overheating. The synergistic effect of the micro-region exothermic peak of CTBN and the thermal diffusion of nano-silica narrows the width of the curing exothermic peak, improving deep curing efficiency.

[0027] Preferably, the mass ratio of nano-silica to CTBN toughening agent in the dual-reinforcement composition is 4:5-8.

[0028] By adopting the above technical solutions, when the mass ratio of CTBN toughening agent is too low, the size of the island structure is easily reduced, stress is difficult to dissipate effectively, and the impact strength is reduced; nano-silica aggregates (unencapsulated rigid particles) are prone to becoming microcrack initiation points, and the fracture toughness decreases; when the mass ratio of CTBN toughening agent is too high, excessive CTBN dilutes the epoxy crosslinking network, resulting in a decrease in tensile strength; the flexible segments of CTBN increase the free volume of the system, delay the diffusion of polyamide curing agent, and prolong the gel time; therefore, after extensive research and experimental verification, the applicant finally determined that the mass ratio of nano-silica to CTBN toughening agent in the dual-reinforcement composition of this application is preferably as described above.

[0029] Preferably, the reinforcing agent is a triple-reinforcing composition of nano-silica, CTBN toughening agent, and zirconium oxide.

[0030] By employing the above technical solution, nano-silica pins cracks at the micrometer scale, zirconia relaxes the stress at the crack tip through phase transformation at the submicrometer scale, and CTBN absorbs energy through elastic deformation at a larger scale (micrometer scale). The crack needs to overcome barriers of different scales sequentially, thus doubling the energy consumption efficiency. Zirconia (rigid phase) and CTBN (elastic phase) form a "rigid-flexible" structure, where zirconia enhances hardness and strength, CTBN compensates for its brittleness, and nano-silica fills the interface between the two, enhancing the interfacial bonding force.

[0031] Nano-silica improves the compatibility between the matrix and zirconium oxide / CTBN, reducing phase separation. The flexible chains of CTBN buffer the volumetric stress generated by the zirconium oxide phase transformation, preventing microcrack initiation. This results in a more uniform microstructure and fewer defects (such as optimized grain size and porosity).

[0032] Secondly, this application provides a method for preparing a fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls, employing the following technical solution: A method for preparing a fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls, comprising the following steps: Preparation of Component A: The prescribed amount of E44 epoxy resin and polyurethane prepolymer are heated and stirred. Then, the prescribed amounts of quartz powder, calcium carbonate and wood fiber are added in sequence and stirred. The prescribed amounts of reinforcing agent and silane coupling agent are added and dispersed and mixed. Defoamer is added and vacuum defoamed to obtain Component A. Preparation of Component B: Mix the polyamide curing agent, DMP-30 and curing aid in the prescribed amounts to obtain Component B; Components A and B were stored separately to obtain a fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls.

[0033] In summary, this application has the following beneficial effects: This application utilizes a combination of polyamide curing agent and DMP-30 to accelerate the reaction between epoxy groups and amine hydrogen, shortening the gel time. Simultaneously, the combination of E44 epoxy resin and polyurethane prepolymer disperses stress through a "sea-island structure," enhancing impact strength and preventing brittle cracking at the rock wool interface. Furthermore, the significant exothermic reaction between the polyurethane prepolymer and E44 epoxy resin raises the initial temperature of the system, accelerating epoxy curing. The synergistic effect of these multiple components results in an adhesive that, when used for bonding rock wool-based composite panels to exterior walls, achieves rapid hardening while maintaining high strength. Detailed Implementation

[0034] E44 epoxy resin: Uses commercially available products with CAS number 61788-97-4; Polyurethane prepolymer: Commercially available product with CAS number 103837-45-2; Polyamide curing agent: A commercially available product with CAS number 63428-84-2 is used; DMP-30: Uses a commercially available product with CAS number 90-72-2; 2-Ethyl-4-methylimidazole: Use the commercially available product with CAS number 931-36-2; Zinc acetylacetone: Use commercially available product with CAS number 14024-63-6; 4-Hydroxymethylbenzyl alcohol: Use the commercially available product with CAS number 623-05-2; CTBN toughening agent: A commercially available product with CAS number 25265-19-4 is used; The present application will be further described in detail below with reference to embodiments and comparative examples.

[0035] Example 1 A method for preparing a fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls includes the following steps: Preparation of Component A: 450g of E44 epoxy resin and 280g of polyurethane prepolymer were heated and stirred at 70℃ for 15min at a stirring speed of 300rpm. Then, 120g of quartz powder, 80g of calcium carbonate and 8g of wood fiber were added in sequence and stirred for 10min at 400rpm after each addition. Then, 15g of silane coupling agent was added and dispersed for 30min at a dispersion speed of 1200rpm. Finally, 3g of defoamer was added and vacuum defoamed for 10min to obtain Component A. Preparation of Component B: Mix 70g of polyamide curing agent and 8g of DMP-30 for 15 minutes at a stirring speed of 500rpm to obtain Component B; Components A and B were stored separately to obtain a fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls.

[0036] The application of a fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls includes the following steps: Take components A and B in a mass ratio of 5:1. First, stir component A evenly, then add component B and stir at 600 rpm for 5 minutes. This mixture is then ready for use as an exterior wall adhesive for rock wool-based composite panels.

[0037] Example 2-3 Based on the preparation method of Example 1, Examples 2-3 adjust the content of each component of the fast-hardening high-strength adhesive used for bonding rock wool-based composite panels to the exterior walls. The specific adjustments are shown in Table 1.

[0038] Comparative Examples 1-2 Comparative Example 1 was prepared using the same method as in Example 1, but without the addition of 280g of polyurethane prepolymer.

[0039] Comparative Example 2 was prepared using the same method as in Example 1, but without the addition of 8g of DMP-30.

[0040] Performance testing The fast-setting, high-strength adhesives used for bonding rock wool-based composite panels to exterior walls in Examples 1-3 and Comparative Examples 1-2 were subjected to the following performance tests, and the test results are shown in Table 1.

[0041] Initial solidification time The initial curing time for the fast-curing, high-strength adhesive used in the examples and comparative examples of bonding rock wool-based composite panels to the exterior walls was determined using a curing time tester to achieve the required service strength.

[0042] Bond strength According to GB / T 50728-2011, the bonding strength of rock wool-based composite panels bonded to concrete using adhesives is determined.

[0043] Table 1. Content (in g) of each component and performance test results of the fast-setting high-strength adhesive used for bonding rock wool-based composite panels to exterior walls in Examples 1-3 and Comparative Examples 1-2. Referring to Table 1, comparing Examples 1-3 and Comparative Examples 1-2, it can be seen that the above formulation can achieve rapid hardening and maintain high strength when the rock wool-based composite board is pasted on the exterior wall. This is because the polyamide curing agent, as the main curing agent, provides a flexible long-chain structure, reducing the cross-linking brittleness of the epoxy resin. Simultaneously, its active amine groups react with the epoxy groups in a ring-opening reaction, achieving medium-speed curing. The DMP-30 accelerator, as a tertiary amine catalyst, accelerates the reaction between the epoxy groups and amine hydrogen, shortening the gel time.

[0044] E44 epoxy resin provides a rigid framework and high adhesion, forming a dense cross-linked network after curing, giving the base strength. The polyurethane prepolymer introduces flexible segments, dispersing stress through an "island structure," improving impact strength and preventing brittle cracking at the rock wool interface. Furthermore, the polyurethane prepolymer contains -NCO groups, which can react with the -OH groups of the epoxy resin to form an oxazolidinone structure. This reaction is significantly exothermic, increasing the initial temperature of the system and accelerating epoxy curing.

[0045] The low-viscosity resin system (E44 epoxy resin + polyurethane prepolymer) can penetrate into the porous structure of rock wool, forming a "riveted" mechanical interlocking after curing. Breakage at the bonding interface requires overcoming the mechanical anchoring force. The polyurethane segments and epoxy combine rigidity and flexibility, making the thermal expansion coefficient of the adhesive layer close to that of rock wool, thus avoiding the risk of debonding due to temperature differences.

[0046] Furthermore, comparison revealed that Example 1 exhibited the best overall performance. Therefore, Example 1 was selected as the preferred embodiment.

[0047] Examples 4-10 Example 4 is based on the preparation method of Example 1, but with adjustments: Preparation of Component B: Mix 70g of polyamide curing agent, 8g of DMP-30 and 9g of 2-ethyl-4-methylimidazol for 15 minutes at a stirring speed of 500 rpm to obtain Component B.

[0048] Example 5 is based on the preparation method of Example 1, but with adjustments: Preparation of Component B: Mix 70g of polyamide curing agent, 8g of DMP-30 and 9g of zinc acetylacetonate for 15 minutes at a stirring speed of 500 rpm to obtain Component B.

[0049] Example 6 is based on the preparation method of Example 1, but with adjustments: Preparation of Component B: Mix 70g of polyamide curing agent, 8g of DMP-30 and 9g of 4-hydroxymethylbenzyl alcohol for 15 minutes at a stirring speed of 500 rpm to obtain Component B.

[0050] Example 7 is based on the preparation method of Example 1, but with adjustments: Preparation of Component B: 70g of polyamide curing agent, 8g of DMP-30, and 9g of the dual-curing composition were stirred and mixed for 15 minutes at a stirring speed of 500 rpm to obtain Component B. The dual-curing composition is a mixture of 2-ethyl-4-methylimidazole and zinc acetylacetonate, with a mass ratio of 2:1.

[0051] Example 8 is based on the preparation method of Example 1, but with adjustments: Preparation of Component B: 70g of polyamide curing agent, 8g of DMP-30, and 9g of the dual-curing composition were stirred and mixed for 15 minutes at a stirring speed of 500 rpm to obtain Component B. The dual-curing composition is a mixture of 2-ethyl-4-methylimidazole and zinc acetylacetone, with a mass ratio of 2-ethyl-4-methylimidazole to 4-hydroxymethylbenzyl alcohol of 2:1.

[0052] Example 9 is based on the preparation method of Example 1, but with adjustments: Preparation of Component B: 70g of polyamide curing agent, 8g of DMP-30, and 9g of the dual-curing composition were stirred and mixed for 15 minutes at a stirring speed of 500 rpm to obtain Component B. The dual-curing composition is a mixture of 2-ethyl-4-methylimidazolium and zinc acetylacetonate, with a mass ratio of zinc acetylacetonate to 4-hydroxymethylbenzyl alcohol of 1:1.

[0053] Example 10 is based on the preparation method of Example 1, but with adjustments made to the preparation method: Preparation of Component B: 70g of polyamide curing agent, 8g of DMP-30, and 9g of the three-curing composition were stirred and mixed for 15 minutes at a stirring speed of 500 rpm to obtain Component B. The three-curing composition is a mixture of 2-ethyl-4-methylimidazole, zinc acetylacetonate, and 4-hydroxymethylbenzyl alcohol, with a mass ratio of 2:1:0.3.

[0054] The fast-setting, high-strength adhesives used for bonding rock wool-based composite panels to exterior walls in Examples 4-10 were subjected to the performance tests described above, and the test results are shown in Table 2.

[0055] Table 2 Performance test results for Examples 1 and 4-10 Referring to Table 2, a comparison of Examples 1 and 4-10 shows that adding at least one of 2-ethyl-4-methylimidazole, zinc acetylacetonate, and 4-hydroxymethylbenzyl alcohol to component B can effectively improve the curing rate. When combined in pairs, the dual-curing composition of 2-ethyl-4-methylimidazole and zinc acetylacetonate is even more effective. This is because the imidazole ring of 2-ethyl-4-methylimidazole contains two nitrogen atoms (tertiary nitrogen at position 1 and secondary nitrogen at position 3). The tertiary nitrogen has strong nucleophilicity and can directly attack the epoxy group to open the ring, forming an oxygen anion active center. The lone pair electrons of the secondary nitrogen can coordinate with zinc ions, enhancing Lewis acid activity. The steric hindrance effect of the ethyl at position 2 and the methyl at position 4 reduces intermolecular aggregation, improves dispersibility in the resin, and prevents the active sites from being blocked.

[0056] The effect is even better when all three are combined. This is because the tertiary amine nitrogen atom (N3) in the 2-ethyl-4-methylimidazol molecule acts as a strong nucleophilic center, directly attacking the epoxy group to open the ring and generate an alkoxy anion, initiating anionic polymerization chain reaction. The zinc ion of zinc acetylacetonate coordinates with the oxygen atom of the epoxy group, polarizing the CO bond, lowering the ring-opening energy barrier, and significantly increasing the reaction rate at low temperatures. The primary hydroxyl group of 4-hydroxymethylbenzyl alcohol acts as a proton donor, promoting the protonation of the alkoxy anion and accelerating chain propagation; the benzene ring structure enhances compatibility with epoxy resins, while preventing the precipitation or aggregation of zinc acetylacetonate through hydrogen bonding.

[0057] Examples 11-12 Examples 11-12 are based on the preparation method of Example 7, but the mass ratio of 2-ethyl-4-methylimidazole and zinc acetylacetonate is adjusted. The specific adjustments are shown in Table 3.

[0058] The fast-setting, high-strength adhesives used for bonding rock wool-based composite panels to exterior walls in Examples 11-12 were subjected to the performance tests described above, and the test results are shown in Table 3.

[0059] Table 3. Mass ratio and performance test results of 2-ethyl-4-methylimidazolium and zinc acetylacetonate in Examples 1, 7, and 11-12. Referring to Table 3, a comparison of Examples 1, 7, and 11-12 shows that as the mass percentage of zinc acetylacetonate increases, the curing efficiency of the adhesive first increases and then decreases. This is because: when the mass percentage of zinc acetylacetonate is too low, its Lewis acid activation ability is insufficient to effectively reduce the ring-opening energy barrier of the epoxy groups, resulting in a slow reaction initiation. The absence of zinc acetylacetonate weakens its stabilizing effect on the oxygen anion intermediate catalyzed by 2-ethyl-4-methylimidazole, leading to premature termination of some chain growth; when the mass percentage of zinc acetylacetonate is too high, Lewis acid overload occurs, the catalytic pathway becomes unbalanced, and excess zinc acetylacetonate over-polarizes the epoxy groups, but insufficient 2-ethyl-4-methylimidazole leads to low anion chain growth efficiency, breaking the synergistic effect between the two; when zinc acetylacetonate is in excess, its ligand acetylacetone residues act as plasticizers, interfering with the densification of the crosslinking network.

[0060] Examples 13-19 Example 13 is based on the preparation method of Example 1, but with adjustments: Pretreatment: Mix 30g of nano-silica with 15g of silane coupling agent for 20 minutes at a stirring rate of 1000 rpm, and then dry at 80°C for 2 hours to obtain the pretreated material. Preparation of Component A: 450g of E44 epoxy resin and 280g of polyurethane prepolymer were heated and stirred at 70℃ for 15min at a stirring rate of 300rpm. Then, 120g of quartz powder, 80g of calcium carbonate, and 8g of wood fiber were added sequentially and stirred for 10min at 400rpm after each addition. Then, the pretreated material was added and dispersed for 30min at a dispersion rate of 1200rpm. Finally, 3g of defoamer was added and vacuum defoamed for 10min to obtain Component A.

[0061] Example 14 is based on the preparation method of Example 1, but with adjustments: Preparation of Component A: 450g of E44 epoxy resin and 280g of polyurethane prepolymer were heated and stirred at 70℃ for 15min at a stirring speed of 300rpm. Then, 120g of quartz powder, 80g of calcium carbonate, and 8g of wood fiber were added sequentially and stirred for 10min at 400rpm after each addition. Then, 30g of CTBN toughening agent and 15g of silane coupling agent were added and dispersed for 30min at a dispersion speed of 1200rpm. Finally, 3g of defoamer was added and vacuum defoamed for 10min to obtain Component A.

[0062] Example 15 is based on the preparation method of Example 1, but with adjustments made to the preparation method: Pretreatment: Mix 30g zirconium oxide and 15g silane coupling agent for 20 minutes at a stirring rate of 1000 rpm, and then dry at 80℃ for 2 hours to obtain the pretreated product; Preparation of Component A: 450g of E44 epoxy resin and 280g of polyurethane prepolymer were heated and stirred at 70℃ for 15min at a stirring rate of 300rpm. Then, 120g of quartz powder, 80g of calcium carbonate, and 8g of wood fiber were added sequentially and stirred for 10min at 400rpm after each addition. Then, the pretreated material was added and dispersed for 30min at a dispersion rate of 1200rpm. Finally, 3g of defoamer was added and vacuum defoamed for 10min to obtain Component A.

[0063] Example 16 adjusts the preparation method based on the preparation method of Example 1: Pretreatment: Nano-silica and 15g of silane coupling agent were stirred and mixed for 20min at a stirring rate of 1000rpm, and then dried at 80℃ for 2h to obtain the pretreated material. Preparation of Component A: 450g of E44 epoxy resin and 280g of polyurethane prepolymer were heated and stirred at 70℃ for 15 minutes at a stirring speed of 300 rpm. Then, 120g of quartz powder, 80g of calcium carbonate, and 8g of wood fiber were added sequentially, and stirring continued. After each addition, the mixture was stirred at 400 rpm for 10 minutes. Then, the pretreated material and CTBN toughening agent were added and dispersed for 30 minutes at a dispersion speed of 1200 rpm. Finally, 3g of defoamer was added and vacuum defoamed for 10 minutes to obtain Component A. Nano-silica and CTBN toughening agent constitute a dual-reinforcing composition with a total mass of 30g. The mass ratio of nano-silica to CTBN toughening agent in the dual-reinforcing composition is 4:7.

[0064] Example 17 is based on the preparation method of Example 1, but with adjustments: Pretreatment: Nano silica, zirconium oxide and 15g silane coupling agent were stirred and mixed for 20min at a stirring rate of 1000rpm, and then dried at 80℃ for 2h to obtain the pretreated material. Preparation of Component A: 450g of E44 epoxy resin and 280g of polyurethane prepolymer were heated and stirred at 70℃ for 15 minutes at a stirring speed of 300 rpm. Then, 120g of quartz powder, 80g of calcium carbonate, and 8g of wood fiber were added sequentially, and stirring continued. After each addition, the mixture was stirred at 400 rpm for 10 minutes. The pretreated material was then added and dispersed for 30 minutes at a dispersion speed of 1200 rpm. Finally, 3g of defoamer was added and vacuum defoamed for 10 minutes to obtain Component A. A dual-reinforced composition consisting of nano-silica and zirconium oxide, with a total mass of 30g, was prepared. The mass ratio of nano-silica to zirconium oxide in the dual-reinforced composition was 4:7.

[0065] Example 18 adjusts the preparation method based on the preparation method of Example 1: Pretreatment: Zirconia and 15g of silane coupling agent were stirred and mixed for 20min at a stirring rate of 1000rpm, and then dried at 80℃ for 2h to obtain the pretreated product; Preparation of Component A: 450g of E44 epoxy resin and 280g of polyurethane prepolymer were heated and stirred at 70℃ for 15 minutes at a stirring speed of 300 rpm. Then, 120g of quartz powder, 80g of calcium carbonate, and 8g of wood fiber were added sequentially, and stirring was continued. After each addition, the mixture was stirred at 400 rpm for 10 minutes. Then, the pretreated material and CTBN toughening agent were added and dispersed for 30 minutes at a dispersion speed of 1200 rpm. Finally, 3g of defoamer was added and vacuum defoamed for 10 minutes to obtain Component A. The CTBN toughening agent and zirconium oxide constitute a dual-reinforcement composition with a total mass of 30g. The mass ratio of CTBN toughening agent to zirconium oxide in the dual-reinforcement composition is 1:1.

[0066] Example 19 is based on the preparation method of Example 1, but with adjustments: Pretreatment: Nano silica, zirconium oxide and 15g silane coupling agent were stirred and mixed for 20min at a stirring rate of 1000rpm, and then dried at 80℃ for 2h to obtain the pretreated material. Preparation of Component A: 450g of E44 epoxy resin and 280g of polyurethane prepolymer were heated and stirred at 70℃ for 15min at a stirring speed of 300rpm. Then, 120g of quartz powder, 80g of calcium carbonate, and 8g of wood fiber were added sequentially, and stirring continued. After each addition, the mixture was stirred at 400rpm for 10min. Then, the pretreated material and CTBN toughening agent were added and dispersed for 30min at a dispersion speed of 1200rpm. Finally, 3g of defoamer was added and vacuum defoamed for 10min to obtain Component A. Nano-silica, CTBN toughening agent, and zirconium oxide constitute a three-reinforcing composition with a total mass of 30g. The mass ratio of nano-silica, CTBN toughening agent, and zirconium oxide in the three-reinforcing composition is 2:4:1.5.

[0067] The fast-setting, high-strength adhesives used for bonding rock wool-based composite panels to exterior walls in Examples 13-19 were subjected to the above performance tests, and the test results are shown in Table 4.

[0068] Table 4 Performance test results for Examples 1 and 13-19 Referring to Table 4, a comparison of Examples 1 and 13-19 shows that adding at least one of nano-silica, CTBN toughening agent, and zirconium oxide to component A effectively improves strength and curing rate. When combined in pairs, the dual-curing composition of 2-ethyl-4-methylimidazole and zinc acetylacetonate exhibits even better results. This is because the terminal carboxyl groups of CTBN pre-react with the epoxy groups of the epoxy resin, precipitating during curing to form an "island structure." This structure acts as a stress concentration point, inducing crazes and shear bands, and absorbing impact energy. The flexible segments of CTBN reduce the system viscosity and promote the diffusion of the polyamide curing agent. Nano-silica fills the micron-level gaps between the CTBN islands, forming a "rigid particle-flexible matrix" composite structure, which prevents crack propagation through crack pinning effect and improves tensile strength.

[0069] The flexible chains of CTBN slow down molecular motion and prolong gel time; while the silanol groups enriched on the surface of nano-silica adsorb the DMP-30 accelerator, forming localized high-concentration catalytic centers that accelerate the epoxy ring-opening reaction. Nano-silica has a significantly higher thermal conductivity than the resin matrix, allowing for rapid dissipation of localized heat released during the CTBN phase transition, preventing uneven curing due to localized overheating. The synergistic effect of the micro-region exothermic peak of CTBN and the thermal diffusion of nano-silica narrows the width of the curing exothermic peak, improving deep curing efficiency.

[0070] The effect is even better when all three are combined. This is because nano-silica pins cracks at the micrometer scale, zirconia relaxes the stress at the crack tip through phase transformation at the submicrometer scale, and CTBN absorbs energy through elastic deformation at a larger scale (micrometer level). The crack must overcome barriers of different scales sequentially, thus multiplying energy consumption efficiency. Zirconia (rigid phase) and CTBN (elastic phase) form a "rigid-flexible" structure, where zirconia enhances hardness and strength, CTBN compensates for brittleness, and nano-silica fills the interface between the two, strengthening the interfacial bonding.

[0071] Nano-silica improves the compatibility between the matrix and zirconium oxide / CTBN, reducing phase separation. The flexible chains of CTBN buffer the volumetric stress generated by the zirconium oxide phase transformation, preventing microcrack initiation. This results in a more uniform microstructure and fewer defects (such as optimized grain size and porosity).

[0072] Examples 20-23 Example 20 is based on the preparation method of Example 16, but the mass ratio of nano-silica and CTBN toughening agent is adjusted to 4:5.

[0073] Example 21 is based on the preparation method of Example 16, but the mass ratio of nano-silica and CTBN toughening agent is adjusted to 4:8.

[0074] Example 22 is based on the preparation method of Example 1, but with adjustments: Pretreatment: Nano-silica and 15g of silane coupling agent were stirred and mixed for 20min at a stirring rate of 1000rpm, and then dried at 80℃ for 2h to obtain the pretreated material. Preparation of Component A: 450g of E44 epoxy resin and 280g of polyurethane prepolymer were heated and stirred at 70℃ for 15min at a stirring speed of 300rpm. Then, 120g of quartz powder, 80g of calcium carbonate, and 8g of wood fiber were added sequentially and stirred for 10min at 400rpm after each addition. Then, the pretreated material and CTBN toughening agent were added and dispersed for 30min at a dispersion speed of 1200rpm. 3g of defoamer was added and vacuum defoamed for 10min to obtain Component A. Nano-silica and CTBN toughening agent form a dual-reinforcement composition with a total mass of 30g. The mass ratio of nano-silica to CTBN toughening agent in the dual-reinforcement composition is 4:7. Preparation of Component B: 70g of polyamide curing agent, 8g of DMP-30, and 9g of the dual-curing composition were stirred and mixed for 15 minutes at a stirring speed of 500 rpm to obtain Component B. The dual-curing composition is a mixture of 2-ethyl-4-methylimidazole and zinc acetylacetonate, with a mass ratio of 2:1.

[0075] Example 23 is based on the preparation method of Example 1, but with adjustments: Pretreatment: Nano silica, zirconium oxide and 15g silane coupling agent were stirred and mixed for 20min at a stirring rate of 1000rpm, and then dried at 80℃ for 2h to obtain the pretreated material. Preparation of Component A: 450g of E44 epoxy resin and 280g of polyurethane prepolymer were heated and stirred at 70℃ for 15min at a stirring speed of 300rpm. Then, 120g of quartz powder, 80g of calcium carbonate, and 8g of wood fiber were added sequentially and stirred for 10min at 400rpm after each addition. Then, the pretreated material and CTBN toughening agent were added and dispersed for 30min at a dispersion speed of 1200rpm. 3g of defoamer was added and vacuum defoamed for 10min to obtain Component A. Nano-silica, CTBN toughening agent, and zirconium oxide constitute a three-reinforcement composition with a total mass of 30g. The mass ratio of nano-silica, CTBN toughening agent, and zirconium oxide in the three-reinforcement composition is 2:4:1.5. Preparation of Component B: 70g of polyamide curing agent, 8g of DMP-30, and 9g of the three-curing composition were stirred and mixed for 15 minutes at a stirring speed of 500 rpm to obtain Component B. The three-curing composition is a mixture of 2-ethyl-4-methylimidazole, zinc acetylacetonate, and 4-hydroxymethylbenzyl alcohol, with a mass ratio of 2:1:0.3.

[0076] The fast-setting, high-strength adhesives used for bonding rock wool-based composite panels to exterior walls in Examples 20-23 were subjected to the performance tests described above, and the test results are shown in Table 5.

[0077] Table 5 Performance test results for Examples 1, 16 and 20-23 Referring to Table 5, a comparison of Examples 1, 16, and 20-23 shows that as the mass proportion of CTBN toughening agent increases, the curing efficiency and strength of the adhesive first increase and then decrease. This is because: when the mass proportion of CTBN toughening agent is too low, the island structure size is easily reduced, stress is difficult to dissipate effectively, and impact strength is reduced; nano-silica aggregates (unencapsulated rigid particles) easily become microcrack initiation points, reducing fracture toughness; when the mass proportion of CTBN toughening agent is too high, excessive CTBN dilutes the epoxy crosslinking network, leading to a decrease in tensile strength; CTBN flexible segments increase the free volume of the system, delaying the diffusion of the polyamide curing agent and prolonging the gel time. Therefore, after extensive research and experimental verification, the applicant finally determined that the mass ratio of nano-silica to CTBN toughening agent in the dual-reinforced composition of this application is preferably as described above.

[0078] In addition, by comparison, adding reinforcing agents to component A and curing agents to component B can simultaneously improve the curing efficiency and strength of the adhesive.

[0079] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls, characterized in that, It includes component A and component B, which comprise the following components in parts by weight: Component A: 40-50 parts E44 epoxy resin, 25-30 parts polyurethane prepolymer, 10-15 parts quartz powder, 5-10 parts calcium carbonate, 0.5-1 part wood fiber, 1-2 parts silane coupling agent, and 0.1-0.5 parts defoamer. Component B: 6-8 parts polyamide curing agent, 0.5-1 part DMP-30.

2. The fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls according to claim 1, characterized in that: Component B also includes a curing aid, which includes at least one of 2-ethyl-4-methylimidazol, zinc acetylacetonate, and 4-hydroxymethylbenzyl alcohol.

3. The fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls according to claim 2, characterized in that: The curing aid is a dual-curing composition of 2-ethyl-4-methylimidazolium and zinc acetylacetonate.

4. The fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls according to claim 3, characterized in that: The mass ratio of 2-ethyl-4-methylimidazolium to zinc acetylacetonate in the dual-curing composition is 2:0.8-1.

2.

5. The fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls according to claim 2, characterized in that: The curing aid is a three-curing composition of 2-ethyl-4-methylimidazol, zinc acetylacetonate, and 4-hydroxymethylbenzyl alcohol.

6. The fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls according to claim 1, characterized in that: The A component also includes reinforcing agents, which include at least one of nano-silica, CTBN toughening agent, and zirconium oxide.

7. The fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls according to claim 6, characterized in that: The reinforcing agent is a dual-reinforcing composition of nano-silica and CTBN toughening agent.

8. The fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls according to claim 7, characterized in that: The mass ratio of nano-silica to CTBN toughening agent in the dual-reinforcement composition is 4:5-8.

9. The fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls according to claim 6, characterized in that: The reinforcing agent is a three-reinforcing composition of nano-silica, CTBN toughening agent, and zirconium oxide.

10. The method for preparing the fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls according to any one of claims 1-9, characterized in that, Includes the following steps: Preparation of Component A: The prescribed amount of E44 epoxy resin and polyurethane prepolymer are heated and stirred. Then, the prescribed amounts of quartz powder, calcium carbonate and wood fiber are added in sequence and stirred. The prescribed amounts of reinforcing agent and silane coupling agent are added and dispersed and mixed. Defoamer is added and vacuum defoamed to obtain Component A. Preparation of Component B: Mix the polyamide curing agent, DMP-30 and curing aid in the prescribed amounts to obtain Component B; Components A and B were stored separately to obtain a fast-setting, high-strength adhesive for bonding rock wool-based composite panels to exterior walls.

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