Cold-formed thin-walled steel light polymer composite wallboard with crack resistance and thermal insulation performance

Abstract

The invention relates to the technical field of building wall materials, and particularly discloses a cold-formed thin-walled steel light polymer composite wallboard with crack resistance and thermal insulation performance, which comprises a cold-formed thin-walled steel skeleton and an enhanced light polymer filler filled in the cold-formed thin-walled steel skeleton, the enhanced light polymer filler is prepared from the following components in parts by weight: 32 to 36 parts of low-alkali cement, 9 to 13 parts of metakaolin, 16 to 21 parts of modified closed cell perlite, 9 to 13 parts of hollow glass beads, 1.8 to 2.6 parts of epoxy modified basalt fiber and 0.4 to 0.9 part of graphene oxide. A composite base material is constructed through low-alkali cement and metakaolin, modified closed cell perlite and hollow glass beads are matched to form a two-stage thermal insulation aggregate, and by combining the elastic buffering effect of a polycaprolactone glycol modified polyurethane prepolymer and the self-repairing function of urea-formaldehyde resin coated epoxy resin microcapsules and an amine latent curing agent, the thermal insulation performance of the composite base material is improved. And the effect of collaborative optimization of heat preservation and crack resistance is achieved.

Description

Technical Field

[0001] This application relates to the field of building wall materials technology, and more specifically, it relates to cold-formed thin-walled steel lightweight polymer composite wall panels that combine crack resistance and thermal insulation properties. Background Technology

[0002] With the development of building energy conservation and prefabricated buildings, cold-formed thin-walled steel lightweight polymer composite wall panels have gradually become an important choice for building walls due to their lightweight, convenient assembly, and high construction efficiency. The core structure of this type of composite wall panel usually consists of a cold-formed thin-walled steel frame and lightweight polymer filler inside the frame. The frame provides structural support, while the lightweight polymer filler achieves thermal insulation. Together, they meet the basic requirements of buildings for the mechanical and energy-saving performance of walls.

[0003] Currently, in related technologies, lightweight polymer fillers are mostly based on cement or gypsum, combined with lightweight insulating aggregates such as polystyrene particles, and some are reinforced with glass fiber to enhance crack resistance. However, high-insulation porous or foamed fillers have low strength and poor toughness, and are prone to cracking due to stress or temperature changes. Excessive addition of fiber components will destroy the porous structure, resulting in a decrease in insulation performance, making it difficult for wall panels to achieve ideal insulation and crack resistance at the same time. Summary of the Invention

[0004] To address the problem that cold-formed thin-walled steel lightweight polymer composite wall panels cannot simultaneously achieve ideal thermal insulation and crack resistance in related technologies, this application provides a cold-formed thin-walled steel lightweight polymer composite wall panel that combines crack resistance and thermal insulation properties.

[0005] The cold-formed thin-walled steel lightweight polymer composite wall panel provided in this application, which combines crack resistance and thermal insulation properties, adopts the following technical solution: In the first aspect, this application provides a cold-formed thin-walled steel lightweight polymer composite wall panel that combines crack resistance and thermal insulation properties, using the following technical solution: A cold-formed thin-walled steel-polymer composite wall panel with both crack resistance and thermal insulation properties includes a cold-formed thin-walled steel frame and reinforcing lightweight polymer filler filled within the cold-formed thin-walled steel frame. The reinforcing lightweight polymer filler comprises the following components by weight: 32-36 parts low-alkali cement, 9-13 parts metakaolin, 16-21 parts modified closed-cell perlite, 9-13 parts hollow glass microspheres, 1.8-2.6 parts epoxy-modified basalt fiber, and oxide... Graphene 0.4-0.9 parts, polycaprolactone diol modified polyurethane prepolymer 3-5 parts, urea-formaldehyde resin coated epoxy resin microcapsules 2-4 parts, amine latent curing agent 0.8-1.2 parts, phase change microcapsules 4-6 parts, nano silica 1.0-1.4 parts, polycarboxylate-based high-efficiency water-reducing agent 0.6-0.9 parts, redispersible latex powder 3-5 parts, defoamer 0.2-0.3 parts, composite anti-aging agent 0.5-0.8 parts.

[0006] By adopting the above technical solution, the composite substrate is constructed using low-alkali cement and metakaolin, combined with modified closed-cell perlite and hollow glass microspheres to form a two-stage thermal insulation aggregate. A multi-dimensional reinforcing network is constructed using epoxy-modified basalt fiber and graphene oxide. This is combined with the elastic buffering effect of polycaprolactone diol-modified polyurethane prepolymer, the self-healing function of urea-formaldehyde resin-coated epoxy resin microcapsules and amine latent curing agents, and the temperature regulation of phase change microcapsules and the long-term protection of composite anti-aging agents. The synergistic effect of each component ensures the porous thermal insulation structure of the filler while improving the toughness and crack resistance of the material. Therefore, a synergistic optimization of thermal insulation and crack resistance is achieved, solving the problem in related technologies where cold-formed thin-walled steel lightweight polymer composite wall panels cannot simultaneously achieve ideal thermal insulation and crack resistance.

[0007] Preferably, the epoxy coating thickness on the surface of the epoxy-modified basalt fiber is 1-3 μm, the number average molecular weight of the polycaprolactone diol-modified polyurethane prepolymer is 2400-2800 Da, and the stress response threshold is 0.5-0.8 MPa.

[0008] By adopting the above technical solutions, the epoxy coating improves the compatibility between basalt fiber and substrate. The appropriate prepolymer molecular weight and stress response threshold enable its elastic network to buffer stress. The two, together with the multidimensional reinforcement network, further optimize the matching of crack resistance and buffering, allowing the material to maintain structural stability under different stress scenarios.

[0009] Preferably, the urea-formaldehyde resin-coated epoxy resin microcapsules have a particle size of 100-200 μm, a core material content of 78-80%, a capsule wall thickness of 10-12 μm, and a compressive strength ≥5 MPa. The amine latent curing agent is dicyandiamide-modified imidazole with an activation temperature of 50-55℃. The composite anti-aging agent is composed of hindered phenolic antioxidants, ultraviolet absorbers, and hindered amine light stabilizers, compounded in a weight ratio of 0.8-1.2:0.8-1.2:0.4-0.6.

[0010] By adopting the above technical solutions, the particle size, core material content and capsule wall thickness of the microcapsules are matched with the filler structure to ensure that they are not damaged during the preparation process and can release the core material when microcracks are generated. Combined with a curing agent with a specific activation temperature, efficient self-repair is achieved. The compounded anti-aging agent provides protection from multiple dimensions such as oxidation and ultraviolet aging, delays material degradation, and extends the long-term stability of the wall panel.

[0011] Preferably, the inner side and welded joints of the cold-formed thin-walled steel frame are provided with an interface buffer adhesive layer, the interface buffer adhesive comprising the following components by weight: 26-31 parts of waterborne epoxy resin emulsion, 16-21 parts of polyurethane elastomer emulsion, 11-16 parts of carboxylated styrene-butadiene rubber latex, 6-9 parts of fumed silica, 0.5-1.0 parts of urea-formaldehyde resin-coated epoxy resin microcapsules, 1-2 parts of silane coupling agent KH-560, and 8-10 parts of polyamide curing agent.

[0012] By adopting the above technical solution, waterborne epoxy resin emulsion is compounded with polyurethane emulsion and carboxylated styrene-butadiene rubber latex. Combined with the thixotropic effect of fumed silica and the improved compatibility of silane coupling agent, the adhesive has both high bonding strength and elastic buffering performance. With the self-healing function of microcapsules, it effectively adapts to the thermal expansion difference between the steel profile and the filler, avoids interface peeling and cracking, and ensures the integrity of the overall structure.

[0013] Secondly, this application provides a method for preparing a cold-formed thin-walled steel lightweight polymer composite wall panel that combines crack resistance and thermal insulation properties, using the following technical solution: A method for preparing a cold-formed thin-walled steel-polymer composite wall panel with both crack resistance and thermal insulation properties, applicable to the aforementioned cold-formed thin-walled steel-polymer composite wall panel with both crack resistance and thermal insulation properties, includes the following steps: Raw material processing: Modified closed-cell perlite, epoxy-modified basalt fiber, urea-formaldehyde resin-coated epoxy resin microcapsules, and polycaprolactone diol-modified polyurethane prepolymer were prepared respectively. Interface preparation: Mix the raw materials of the interface buffer binder according to the weight parts, and stir and mature to obtain the interface buffer binder; Skeleton processing: Cut and splice cold-formed thin-walled steel to form a skeleton, sandblast to remove rust, apply epoxy zinc-rich primer, and then apply interface buffer adhesive to obtain a pre-treated cold-formed thin-walled steel skeleton. Filler preparation: The raw materials of the reinforced light polymer filler are mixed according to the weight parts to obtain the reinforced light polymer filler; Filling molding: Inject the reinforced lightweight polymer filler into the pretreated cold-formed thin-walled steel frame, vibrate to vent the air, and then let it stand to initially cure, forming a cured wall panel; Curing treatment: After the cured wall panel is cured in stages with controlled temperature and humidity, the surface is polished to complete the preparation.

[0014] By adopting the above technical solutions, raw material processing lays the foundation for the performance of each functional component, interface preparation and skeleton treatment ensure the stable combination of skeleton and filler, filler preparation ensures uniform dispersion of each component through orderly mixing, and filling molding and staged curing achieve full hydration and performance stability of the material.

[0015] Preferably, in the raw material processing step, the modified closed-cell perlite is prepared as follows: the closed-cell perlite is dried at 100-105℃ for 3-4 hours until the moisture content is ≤0.5%, cooled, and then immersed in a 5-8% concentration of silane coupling agent KH-550 ethanol solution, stirred at 80-90℃ and 300-400rpm for 2-3 hours, filtered, and then dried at 110-120℃ for 1.5-2 hours. The amount of silane coupling agent KH-550 is 0.8-1.2% of the mass of the closed-cell perlite. The preparation of the epoxy-modified basalt fiber is as follows: basalt fiber is cut to 6-10 mm, rinsed, and then soaked in 3-5% sodium hydroxide solution at room temperature for 30-40 min. After activation, it is rinsed until neutral and dried. Then it is soaked in 10-15% epoxy resin ethanol solution at room temperature for 1-1.5 h and cured at 120-130℃ for 2-2.5 h.

[0016] By adopting the above technical solutions, the surface compatibility of closed-cell perlite is improved through modification processes, resulting in a stronger bond with the substrate while retaining its porous thermal insulation properties. After activation and epoxy modification, the surface activity of basalt fiber is enhanced, improving its bonding force with other components. The cutting length is adapted to the filler structure, further strengthening the multidimensional reinforcement effect.

[0017] Preferably, in the raw material processing step, the preparation of the urea-formaldehyde resin-coated epoxy resin microcapsules is as follows: epoxy resin is melted at 55-65℃ and then added to an aqueous solution containing 0.5-1.0% Tween-80. The mixture is stirred at 1000-1200 rpm for 30-40 min to form an emulsion. Urea-formaldehyde resin prepolymer is added, the pH is adjusted to 4.0-4.5, and the mixture is kept at 50-60℃ and stirred at 500-600 rpm for 2-3 h. After cooling, the mixture is washed and dried. The solid content of the urea-formaldehyde resin prepolymer is 60-65%, and the number average molecular weight is 1000-2000 Da. The preparation of the polycaprolactone diol modified polyurethane prepolymer is as follows: polycaprolactone diol and MDI are mixed at a molar ratio of 1:2, stirred and reacted under nitrogen protection at 80-90℃, and 0.1-0.2% dibutyltin dilaurate is added until the NCO content is 8.5-9.5%.

[0018] By adopting the above technical solutions, the microcapsule preparation process ensures uniform capsule wall formation, stable structure, and core material content meeting standards; the prepolymer preparation process controls NCO content and molecular weight to ensure its elastic buffering performance.

[0019] Preferably, in the interface preparation step, the mixing involves sequentially stirring the aqueous epoxy resin emulsion, polyurethane elastomer emulsion, and carboxylated styrene-butadiene rubber latex at 500-600 rpm for 10-15 min, then adding fumed silica, silane coupling agent KH-560, and urea-formaldehyde resin-coated epoxy resin microcapsules, continuing to stir at 500-600 rpm for 15-20 min, then adding a polyamide curing agent and stirring at 300-400 rpm for 8-10 min, and the stirring and maturation process involves standing at room temperature for 15-20 min. In the skeleton treatment step, the sandblasting pressure for rust removal is 0.4-0.6MPa, the sandblasting time is 5-8min, the coating thickness of the epoxy zinc-rich primer is 80-100μm, the coating thickness of the interface buffer binder is 0.8-1.2mm, and the coating is left at room temperature for 30-40min.

[0020] By adopting the above technical solutions, the step-by-step mixing and curing process ensures that the components of the binder are mixed evenly and have stable performance; the skeleton sandblasting and primer application improve the anti-corrosion effect and surface adhesion; the binder coating thickness and placement time ensure the formation of the pre-bonded layer, laying the foundation for a firm bond between the skeleton and the filler.

[0021] Preferably, in the filler preparation step, the mixing involves stirring low-alkali cement, metakaolin, modified closed-cell perlite, and hollow glass microspheres at 800-1000 rpm for 15-20 min, then adding epoxy-modified basalt fiber, graphene oxide, nano-silica, and composite anti-aging agent, stirring at 800-1000 rpm for 20-25 min, followed by adding redispersible latex powder, polycarboxylate-based high-efficiency water-reducing agent, and defoamer, stirring for 5-8 min, then adding 12-18% of deionized water by mass of the mixture, stirring at 600-800 rpm for 25-30 min, then adding polycaprolactone diol-modified polyurethane prepolymer, stirring at 500-600 rpm for 8-10 min, then adding phase change microcapsules, urea-formaldehyde resin-coated epoxy resin microcapsules, and amine latent curing agent, stirring at 300-400 rpm for 5-10 min; In the filling and molding step, the injection pressure is 0.3-0.5MPa, the injection speed is 5-8L / min, the vibration venting frequency is 50-60Hz, the time is 5-8min, and the initial curing is allowed to stand at room temperature for 22-26h.

[0022] By adopting the above technical solutions, the stirring speed and time are adjusted in an orderly manner according to the characteristics of the raw materials to avoid damage to the functional components and ensure that each component is evenly dispersed; the grouting pressure and speed are adapted to the skeleton structure, vibration and air venting reduce internal voids, and static curing lays the foundation for subsequent maintenance, ensuring the compactness and uniformity of the filler.

[0023] Preferably, in the curing process, the phased temperature and humidity control curing includes curing at 20-25℃ and 80-90% humidity for 7 days, continuing curing at 60-70% humidity for 14 days, and raising the temperature to 50-55℃ and holding for 3-4 hours on the 15th-21st day of curing. After polishing, the surface flatness is ≤3mm / m, and the surface is stored at an ambient temperature of 15-25℃, relative humidity ≤60%, and storage period ≤12 months.

[0024] By adopting the above technical solution, the phased temperature and humidity curing promotes the full hydration and hardening of the substrate, improves the strength and stability of the material, and the high temperature in the later stage activates the latent curing agent to ensure that the self-healing system is in a stable and ready-to-use state. Standardized storage conditions prevent the performance degradation of the finished product.

[0025] In summary, this application has the following beneficial effects: 1. Because this application uses low-alkali cement and metakaolin to construct a composite substrate, combined with modified closed-cell perlite and hollow glass microspheres to form a two-stage thermal insulation aggregate, and relies on epoxy-modified basalt fiber and graphene oxide to construct a multi-dimensional reinforcing network, combined with the elastic buffering effect of polycaprolactone diol modified polyurethane prepolymer, and the self-healing function of urea-formaldehyde resin-coated epoxy resin microcapsules and amine latent curing agents, supplemented by the temperature regulation of phase change microcapsules and the long-term protection of composite anti-aging agents, the synergistic effect of each component not only ensures the porous thermal insulation structure of the filler, but also improves the toughness and crack resistance of the material. Therefore, the effect of synergistic optimization of thermal insulation and crack resistance performance is achieved.

[0026] 2. This application utilizes an interface buffer adhesive layer set on the inner side of the frame and at the welding joints. This layer combines water-based epoxy resin emulsion, polyurethane elastomer emulsion, and carboxylated styrene-butadiene rubber latex, which has both high-strength bonding ability and suitable elastic deformation characteristics. It adapts to the difference in thermal expansion coefficients between the steel and the filler, and alleviates the interface stress generated during temperature cycling or slight structural deformation. At the same time, the urea-formaldehyde resin added to the adhesive encapsulates epoxy resin microcapsules, which can trigger self-repair when micro-cracks appear at the interface, further consolidating the bonding state between the frame and the filler, ensuring the overall structural integrity of the wall panel, and reducing the degradation of thermal insulation performance caused by interface problems.

[0027] 3. This application uses a composite anti-aging agent composed of hindered phenolic antioxidants, ultraviolet absorbers and hindered amine light stabilizers, which can protect the material from multiple dimensions such as oxidative degradation and ultraviolet aging. The phase change microcapsules can regulate the fluctuation of ambient temperature and reduce the impact of temperature stress on the wall panel. After targeted modification treatment, the compatibility and bonding force of various raw materials with the substrate are improved. Combined with the self-healing system to timely compensate for micro-damage, the wall panel can maintain stable thermal insulation, crack resistance and structural performance even after long-term use or in harsh environments. Attached Figure Description

[0028] Figure 1 This is a flowchart of the preparation method of the cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties provided in this application. Detailed Implementation

[0029] The present application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0030] Technical Concept: Cold-formed thin-walled steel lightweight polymer composite wall panels in related technologies generally suffer from problems such as difficulty in simultaneously achieving thermal insulation and crack resistance, unstable interfacial bonding, and significant performance degradation after long-term use. This is mainly because traditional fillers often use a single insulating aggregate combined with simple reinforcing components, resulting in a lack of synergy in structural design. This makes it impossible to simultaneously meet the requirements of porous insulation and high-toughness crack resistance. The thermal expansion coefficients of the steel and the filler differ significantly, and the interface relies solely on a basic adhesive for bonding, lacking an elastic buffering mechanism. Consequently, the wall panel is prone to cracking under temperature changes or stress, the interface is easily degraded, and the insulation and structural performance continuously declines after long-term use.

[0031] Based on the above-mentioned problems, this application addresses the issue by using low-alkali cement and metakaolin as composite substrates, combined with modified closed-cell perlite and hollow glass microspheres to form a two-stage thermal insulation aggregate. It leverages epoxy-modified basalt fiber and graphene oxide to construct a multi-dimensional reinforcing network, combined with the dynamic stress buffering effect of polycaprolactone diol-modified polyurethane prepolymer, and the self-healing function of urea-formaldehyde resin-coated epoxy resin microcapsules and amine-based latent curing agents. Furthermore, it adds compound anti-aging agents and phase change microcapsules to enhance long-term stability. A specially designed adhesive layer with both high bonding strength and elastic buffering performance is also incorporated at the interface to accommodate the thermal expansion differences between the steel profile and the filler. The synergistic effect of these technologies solves the problem in related technologies where cold-formed thin-walled steel lightweight polymer composite wall panels struggle to simultaneously achieve ideal thermal insulation and crack resistance.

[0032] Unless otherwise specified, all experimental methods used below are conventional methods. All materials, reagents, methods, and instruments used, unless otherwise specified, are conventional materials, reagents, methods, and instruments in this field, which can be obtained commercially or prepared according to literature methods by those skilled in the art.

[0033] Preparation Example 1: Preparation of Amine-based Latent Curing Agents Raw materials for preparation: 50g dicyandiamide, 30g 2-methylimidazole, 200mL anhydrous ethanol, 15mL 37% formaldehyde aqueous solution; Preparation steps: Dicyandiamide and anhydrous ethanol were added to a 500 mL three-necked flask, heated to 60 °C, and stirred at 300 rpm until completely dissolved; then formaldehyde aqueous solution was added dropwise at a rate of 5 mL / min. After the addition was completed, the mixture was stirred at 300 rpm for 2 h at 60 °C to carry out the hydroxymethylation reaction. Then 2-methylimidazole was added, the temperature was raised to 75 °C, and the mixture was stirred for another 3 h to complete the modification reaction. Finally, the mixture was distilled under reduced pressure at -0.08 MPa and 70 °C to remove ethanol and excess formaldehyde, yielding a pale yellow solid. The solid was pulverized and passed through a 200-mesh sieve, then placed in a vacuum drying oven and dried at 80°C for 4 hours to obtain a dicyandiamide-modified imidazole curing agent.

[0034] Preparation Example 2: Preparation of Phase Change Microcapsules Raw materials for preparation: 80g n-octadecane, 120g urea-formaldehyde resin prepolymer with 65% solid content, 2g Tween-80, 300mL deionized water, appropriate amount of 10% hydrochloric acid, appropriate amount of 10% sodium hydroxide. Preparation steps: Heat n-octadecane to 50°C to melt, add Tween-80 and stir until homogeneous to obtain the oil phase; Add deionized water to a 1000 mL beaker, heat to 50 °C, stir at 800 rpm, slowly add the oil phase, and continue stirring for 30 min to form a water-in-oil emulsion with a particle size of 50-100 μm. Adjust the pH of the emulsion to 4.0-4.5, add urea-formaldehyde resin prepolymer, and stir at 50°C and 500 rpm for 3 hours to allow the urea-formaldehyde resin to polymerize on the surface of the oil droplets to form a capsule wall. Adjust the pH to 7.0 with an aqueous sodium hydroxide solution, stop the reaction, and cool to room temperature; The microcapsules were collected by vacuum filtration, washed three times with deionized water, and dried at 105℃ for 2 hours to obtain phase change microcapsules.

[0035] To better understand the above technical solutions, the technical solutions of the present invention will be clearly and completely described below in conjunction with embodiments.

[0036] The following is a further description with reference to the embodiments: Example 1: A cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties, comprising a cold-formed thin-walled steel frame and reinforcing lightweight polymer filler filled within the cold-formed thin-walled steel frame. The reinforcing lightweight polymer filler comprises the following components by weight: 34 parts low-alkali cement, 11 parts metakaolin, 18.5 parts modified closed-cell perlite, 11 parts hollow glass microspheres, 2.2 parts epoxy-modified basalt fiber, 0.65 parts graphene oxide, 4 parts polycaprolactone diol-modified polyurethane prepolymer, 3 parts urea-formaldehyde resin-coated epoxy resin microcapsules, 1 part amine latent curing agent, 5 parts phase change microcapsules, 1.2 parts nano silica, 0.75 parts polycarboxylate-based high-efficiency water-reducing agent, 4 parts redispersible latex powder, 0.25 parts defoamer, and 0.65 parts composite anti-aging agent.

[0037] The epoxy coating on the surface of the epoxy-modified basalt fiber is 2 μm thick, the number-average molecular weight of the polycaprolactone diol-modified polyurethane prepolymer is 2600 Da, and the stress response threshold is 0.65 MPa.

[0038] The urea-formaldehyde resin-coated epoxy resin microcapsules have a particle size of 150 μm, a core material content of 79%, a capsule wall thickness of 11 μm, and a compressive strength ≥5 MPa. The amine-based latent curing agent is dicyandiamide-modified imidazole with an activation temperature of 52.5℃. The composite anti-aging agent is composed of hindered phenolic antioxidants, ultraviolet absorbers, and hindered amine light stabilizers, compounded in a weight ratio of 1:1:0.5.

[0039] An interface buffer adhesive layer is provided on the inner side and at the welded joints of the cold-formed thin-walled steel frame. The interface buffer adhesive comprises the following components by weight: 28.5 parts of water-based epoxy resin emulsion, 18.5 parts of polyurethane elastomer emulsion, 13.5 parts of carboxylated styrene-butadiene rubber latex, 7.5 parts of fumed silica, 0.75 parts of urea-formaldehyde resin-coated epoxy resin microcapsules, 1.5 parts of silane coupling agent KH-560, and 9.5 parts of polyamide curing agent.

[0040] Please see the appendix Figure 1 A method for preparing a cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties, applicable to the aforementioned cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties, includes the following steps: Raw material processing: Modified closed-cell perlite, epoxy-modified basalt fiber, urea-formaldehyde resin-coated epoxy resin microcapsules, and polycaprolactone diol-modified polyurethane prepolymer were prepared respectively. Interface preparation: Mix the raw materials of the interface buffer binder according to the weight parts, and stir and mature to obtain the interface buffer binder; Skeleton processing: Cut and splice cold-formed thin-walled steel to form a skeleton, sandblast to remove rust, apply epoxy zinc-rich primer, and then apply interface buffer adhesive to obtain a pre-treated cold-formed thin-walled steel skeleton. Filler preparation: The raw materials of the reinforced light polymer filler are mixed according to the weight parts to obtain the reinforced light polymer filler; Filling molding: Inject the reinforced lightweight polymer filler into the pretreated cold-formed thin-walled steel frame, vibrate to vent the air, and then let it stand to initially cure, forming a cured wall panel; Curing treatment: After the cured wall panel is cured in stages with controlled temperature and humidity, the surface is polished to complete the preparation.

[0041] In the raw material processing steps, the modified closed-cell perlite is prepared as follows: the closed-cell perlite is dried at 105℃ for 3.5h until the water content is ≤0.5%, cooled, and then immersed in a 6.5% concentration of silane coupling agent KH-550 ethanol solution. The mixture is stirred at 85℃ and 350rpm for 2.5h, filtered, and then dried at 115℃ for 1.75h. The amount of silane coupling agent KH-550 used is 1% of the mass of the closed-cell perlite. The preparation of epoxy-modified basalt fiber is as follows: basalt fiber is cut to 8mm, rinsed and then soaked in 4% sodium hydroxide solution at room temperature for 35min. After activation, it is rinsed until neutral and dried. Then it is soaked in 12.5% ​​epoxy resin ethanol solution at room temperature for 1.25h and cured at 125℃ for 2.25h.

[0042] In the raw material processing steps, the preparation of urea-formaldehyde resin-coated epoxy resin microcapsules is as follows: epoxy resin is melted at 60℃ and then added to an aqueous solution containing 0.75% Tween-80. The mixture is stirred at 1100 rpm for 35 min to form an emulsion. Urea-formaldehyde resin prepolymer is added, the pH is adjusted to 4.25, and the mixture is kept at 55℃ and stirred at 550 rpm for 2.5 h. After cooling, the mixture is washed and dried. The solid content of the urea-formaldehyde resin prepolymer is 62.5%, and the number average molecular weight is 1500 Da. The preparation of polycaprolactone diol modified polyurethane prepolymer is as follows: polycaprolactone diol and MDI are mixed at a molar ratio of 1:2, stirred and reacted under nitrogen protection at 85°C, and 0.15% dibutyltin dilaurate is added, and the reaction is continued until the NCO content is 9%.

[0043] In the interface preparation step, the mixing process involves sequentially stirring the aqueous epoxy resin emulsion, polyurethane emulsion, and carboxylated styrene-butadiene rubber latex at 550 rpm for 12.5 min, then adding fumed silica, silane coupling agent KH-560, and urea-formaldehyde resin-coated epoxy resin microcapsules, and continuing to stir at 550 rpm for 17.5 min, followed by adding a polyamide curing agent and stirring at 350 rpm for 9 min, and then allowing the mixture to stand at room temperature for 17.5 min. In the skeleton treatment step, the sandblasting pressure for rust removal is 0.5MPa, the sandblasting time is 6.5min, the coating thickness of the epoxy zinc-rich primer is 90μm, the coating thickness of the interface buffer binder is 1mm, and the coating is left at room temperature for 35min after application.

[0044] In the filler preparation step, the mixing process involves stirring low-alkali cement, metakaolin, modified closed-cell perlite, and hollow glass microspheres at 900 rpm for 17.5 min, followed by adding epoxy-modified basalt fiber, graphene oxide, nano-silica, and a composite anti-aging agent at 900 rpm for 22.5 min, then adding redispersible latex powder, polycarboxylate-based high-efficiency water-reducing agent, and defoamer, and stirring for 6.5 min. Next, deionized water accounting for 15% of the total mass of the mixture is added, and the mixture is stirred at 700 rpm for 27.5 min. Then, polycaprolactone diol-modified polyurethane prepolymer is added, and the mixture is stirred at 550 rpm for 9 min. Finally, phase change microcapsules, urea-formaldehyde resin-coated epoxy resin microcapsules, and an amine latent curing agent are added, and the mixture is stirred at 350 rpm for 7.5 min. In the filling and molding step, the injection pressure is 0.4 MPa, the injection speed is 6.5 L / min, the vibration venting frequency is 55 Hz, the time is 6.5 min, and the initial curing is allowed to stand at room temperature for 24 h.

[0045] The curing process involves phased temperature and humidity control, including curing at 22.5℃ and 85% humidity for 7 days, followed by curing at 65% humidity for 14 days. From day 15 to 21 of curing, the temperature is raised to 52.5℃ and held for 3.5 hours. After polishing, the surface flatness is ≤3mm / m, and the surface is stored at an ambient temperature of 20℃, relative humidity ≤60%, and a shelf life of ≤12 months.

[0046] Example 2: This example differs from Example 1 above in that: The cold-formed thin-walled steel lightweight polymer composite wall panel, which combines crack resistance and thermal insulation properties, includes a cold-formed thin-walled steel frame and reinforcing lightweight polymer filler filled within the cold-formed thin-walled steel frame. The reinforcing lightweight polymer filler comprises the following components by weight: 32 parts low-alkali cement, 9 parts metakaolin, 16 parts modified closed-cell perlite, 9 parts hollow glass microspheres, 1.8 parts epoxy-modified basalt fiber, 0.4 parts graphene oxide, 3 parts polycaprolactone diol-modified polyurethane prepolymer, 2 parts urea-formaldehyde resin-coated epoxy resin microcapsules, 0.8 parts amine latent curing agent, 4 parts phase change microcapsules, 1.0 part nano silica, 0.6 parts polycarboxylate-based high-efficiency water-reducing agent, 3 parts redispersible latex powder, 0.2 parts defoamer, and 0.5 parts composite anti-aging agent.

[0047] Example 3: This example differs from Example 1 above in that: The cold-formed thin-walled steel lightweight polymer composite wall panel, which combines crack resistance and thermal insulation properties, includes a cold-formed thin-walled steel frame and reinforcing lightweight polymer filler filled within the cold-formed thin-walled steel frame. The reinforcing lightweight polymer filler comprises the following components by weight: 36 parts low-alkali cement, 13 parts metakaolin, 16-21 parts modified closed-cell perlite, 9-13 parts hollow glass microspheres, 2.6 parts epoxy-modified basalt fiber, 0.9 parts graphene oxide, 5 parts polycaprolactone diol-modified polyurethane prepolymer, 4 parts urea-formaldehyde resin-coated epoxy resin microcapsules, 1.2 parts amine latent curing agent, 6 parts phase change microcapsules, 1.4 parts nano silica, 0.9 parts polycarboxylate-based high-efficiency water-reducing agent, 5 parts redispersible latex powder, 0.3 parts defoamer, and 0.8 parts composite anti-aging agent.

[0048] Example 4: This example differs from Example 1 above in that: An interface buffer adhesive layer is provided on the inner side and at the welded joints of the cold-formed thin-walled steel frame. The interface buffer adhesive includes the following components by weight: 26 parts of water-based epoxy resin emulsion, 16 parts of polyurethane elastomer emulsion, 11 parts of carboxylated styrene-butadiene rubber latex, 6 parts of fumed silica, 0.5 parts of urea-formaldehyde resin-coated epoxy resin microcapsules, 1 part of silane coupling agent KH-560, and 8 parts of polyamide curing agent.

[0049] Example 5: This example differs from Example 1 above in that: An interface buffer adhesive layer is provided on the inner side and at the welded joints of the cold-formed thin-walled steel frame. The interface buffer adhesive includes the following components by weight: 31 parts of waterborne epoxy resin emulsion, 21 parts of polyurethane elastomer emulsion, 16 parts of carboxylated styrene-butadiene rubber latex, 9 parts of fumed silica, 1 part of urea-formaldehyde resin-coated epoxy resin microcapsules, 2 parts of silane coupling agent KH-560, and 10 parts of polyamide curing agent.

[0050] Comparative Example 1: Cold-formed thin-walled steel lightweight polymer composite wall panel, comprising a cold-formed thin-walled steel frame and lightweight polymer filler filled within the cold-formed thin-walled steel frame. The lightweight polymer filler comprises the following components by weight: 40 parts low-alkali cement, 15 parts fly ash, 20 parts polystyrene particles, 1.5 parts glass fiber, 0.5 parts polycarboxylate superplasticizer, 3 parts redispersible latex powder, and deionized water to make up to 100 parts.

[0051] A method for preparing cold-formed thin-walled steel lightweight polymer composite wall panels includes the following steps: Cut and splice cold-formed thin-walled steel to form a skeleton, and then apply epoxy adhesive after sandblasting to remove rust. The raw materials of the light polymer filler are mixed according to the weight proportions and then filled, and cured at room temperature for 28 days.

[0052] Comparative Example 2: This comparative example differs from Example 1 above in that: The reinforced lightweight polymer filler contains no polycaprolactone diol-modified polyurethane prepolymer; The rest is the same as in Example 1.

[0053] Comparative Example 3: This comparative example differs from Example 1 above in that: The reinforced lightweight polymer filler contains no urea-formaldehyde resin-coated epoxy resin microcapsules and no amine-based latent curing agents; The rest is the same as in Example 1.

[0054] Comparative Example 4: This comparative example differs from Example 1 above in that: The reinforced lightweight polymer filler contains 1.2 parts of polycaprolactone diol-modified polyurethane prepolymer and 1.5 parts of urea-formaldehyde resin-coated epoxy resin microcapsules. The rest is the same as in Example 1.

[0055] Comparative Example 5: This comparative example differs from Example 1 above in that: The inner side of the cold-formed thin-walled steel frame and the welded joints are only coated with epoxy zinc-rich primer, and no interface buffer adhesive is applied. The rest is the same as in Example 1.

[0056] Performance testing: Thermal conductivity: GB / T 10294-2008 "Determination of steady-state thermal resistance and related properties of thermal insulation materials - protective hot plate method"; Compressive strength: GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; Elongation at break: GB / T 14683-2017 "Silicone and Modified Silicone Building Sealants"; Interface adhesion: GB / T 5210-2006 "Paints and Varnishes - Pull-off test for adhesion"; Temperature cycling stability: Simulate temperature cycling from -20℃ to 60℃ for 1000 cycles, and test whether cracking occurs and the rate of change of thermal conductivity after cycling; Artificial accelerated aging performance: GB / T 16422.2-2014 "Laboratory Light Source Exposure Test Methods for Plastics - Part 2: Xenon Arc Lamp", after aging for 2000h, the retention rate of elongation at break and the rate of change of thermal conductivity were tested.

[0057] Table 1 Group Thermal conductivity (W / (m・K)) Compressive strength (MPa) Elongation at break (%) Interfacial adhesion (MPa) Cracking after 1000 temperature cycles Change rate of thermal conductivity (%) after 1000 temperature cycles Elongation at break retention rate (%) after 2000h of artificial accelerated aging Change rate of thermal conductivity (%) after 2000h of artificial accelerated aging Example 1 0.033 3.8 1.6 1.2 No cracks 3.0 92 4.5 Example 2 0.034 3.6 1.5 1.1 No cracks 3.2 90 4.8 Example 3 0.032 3.9 1.7 1.3 No cracks 2.8 93 4.2 Example 4 0.034 3.7 1.5 1.0 No cracks 3.5 89 5.0 Example 5 0.033 3.8 1.6 1.2 No cracks 3.1 91 4.6 Comparative Example 1 0.048 2.5 0.8 0.6 Multiple cracks 25.0 65 28.3 Comparative Example 2 0.035 3.0 0.9 0.9 Local microcracks 18.2 62 24.1 Comparative Example 3 0.034 3.1 0.8 0.8 Multiple microcracks 24.1 58 26.7 Comparative Example 4 0.036 2.8 0.7 0.7 Obvious cracks 22.2 55 30.9 Comparative Example 5 0.035 2.9 0.8 0.5 Severe cracking 28.6 53 32.1 As can be seen from Examples 1 to 5 and Comparative Example 1, and in conjunction with Table 1, this application constructs a system with both buffering and repair functions through the synergistic combination of various components, while optimizing the interface bonding between the skeleton and the filler, so that the composite wall panel can form a comprehensive performance advantage in terms of thermal insulation, crack resistance, structural strength, interface bonding and long-term stability.

[0058] As can be seen from Example 1 and Comparative Example 2 and Table 1, the addition of polycaprolactone diol-modified polyurethane prepolymer to the reinforced light polymer filler in this application can buffer stress, reduce crack generation, and enable the wall panel to maintain good integrity during temperature cycling and aging, thereby reducing the degree of performance degradation.

[0059] As can be seen from Example 1 and Comparative Example 3, and Table 1, the present application combines urea-formaldehyde resin-coated epoxy resin microcapsules with amine latent curing agents to form a self-healing system in reinforced lightweight polymer fillers. This system can compensate for micro-damage, maintain the overall performance of the wall panel, and improve stability after long-term use.

[0060] As can be seen from Example 1 and Comparative Example 4, and Table 1, this application achieves synergistic effects of buffering and repair functions by limiting the weight proportions of polycaprolactone diol-modified polyurethane prepolymer and urea-formaldehyde resin-coated epoxy resin microcapsules, thereby ensuring the structural strength, crack resistance, and long-term stability of the wall panel.

[0061] As can be seen from Example 1 and Comparative Example 5 and Table 1, this application provides an interface buffer adhesive layer on the inner side of the cold-formed thin-walled steel frame and at the welded joints. This adhesive layer has both bonding and buffering properties, adapts to the thermal expansion difference between the frame and the filler, avoids interface peeling, improves the bonding force between the two, and reduces cracking and thermal insulation performance degradation.

[0062] As can be seen from Examples 4 and 1 and Table 1, this application uses an interface buffer adhesive designed based on the synergistic effect of bonding and buffering functions to enable the adhesive to have both sufficient bonding strength and elastic buffering effect, ensuring the stable bonding of the skeleton and the filler and avoiding interface stress concentration.

[0063] 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 cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties, comprising a cold-formed thin-walled steel frame and reinforcing lightweight polymer filler filled within the cold-formed thin-walled steel frame, characterized in that, The reinforced lightweight polymer filler comprises the following components by weight: 32-36 parts low-alkali cement, 9-13 parts metakaolin, 16-21 parts modified closed-cell perlite, 9-13 parts hollow glass microspheres, 1.8-2.6 parts epoxy-modified basalt fiber, 0.4-0.9 parts graphene oxide, 3-5 parts polycaprolactone diol-modified polyurethane prepolymer, 2-4 parts urea-formaldehyde resin-coated epoxy resin microcapsules, 0.8-1.2 parts amine latent curing agent, 4-6 parts phase change microcapsules, 1.0-1.4 parts nano silica, 0.6-0.9 parts polycarboxylate-based high-efficiency water-reducing agent, 3-5 parts redispersible latex powder, 0.2-0.3 parts defoamer, and 0.5-0.8 parts composite anti-aging agent.

2. The cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties according to claim 1, characterized in that: The epoxy coating thickness of the epoxy-modified basalt fiber is 1-3 μm, the number average molecular weight of the polycaprolactone diol-modified polyurethane prepolymer is 2400-2800 Da, and the stress response threshold is 0.5-0.8 MPa.

3. The cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties according to claim 1, characterized in that: The urea-formaldehyde resin-coated epoxy resin microcapsules have a particle size of 100-200 μm, a core material content of 78-80%, a capsule wall thickness of 10-12 μm, and a compressive strength ≥5 MPa. The amine-based latent curing agent is dicyandiamide-modified imidazole with an activation temperature of 50-55℃. The composite anti-aging agent is composed of hindered phenolic antioxidants, ultraviolet absorbers, and hindered amine light stabilizers, compounded in a weight ratio of 0.8-1.2:0.8-1.2:0.4-0.

6.

4. The cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties according to claim 1, characterized in that: The inner side and welded joints of the cold-formed thin-walled steel frame are provided with an interface buffer adhesive layer. The interface buffer adhesive comprises the following components by weight: 26-31 parts of waterborne epoxy resin emulsion, 16-21 parts of polyurethane elastomer emulsion, 11-16 parts of carboxylated styrene-butadiene rubber latex, 6-9 parts of fumed silica, 0.5-1.0 parts of urea-formaldehyde resin-coated epoxy resin microcapsules, 1-2 parts of silane coupling agent KH-560, and 8-10 parts of polyamide curing agent.

5. A method for preparing a cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties, characterized in that: The application of the cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties as described in any one of claims 1-4 includes the following steps: Raw material processing: Modified closed-cell perlite, epoxy-modified basalt fiber, urea-formaldehyde resin-coated epoxy resin microcapsules, and polycaprolactone diol-modified polyurethane prepolymer were prepared respectively. Interface preparation: Mix the raw materials of the interface buffer binder according to the weight parts, and stir and mature to obtain the interface buffer binder; Skeleton processing: Cut and splice cold-formed thin-walled steel to form a skeleton, sandblast to remove rust, apply epoxy zinc-rich primer, and then apply interface buffer adhesive to obtain a pre-treated cold-formed thin-walled steel skeleton. Filler preparation: The raw materials of the reinforced light polymer filler are mixed according to the weight parts to obtain the reinforced light polymer filler; Filling molding: Inject the reinforced lightweight polymer filler into the pretreated cold-formed thin-walled steel frame, vibrate to vent the air, and then let it stand to initially cure, forming a cured wall panel; Curing treatment: After the cured wall panel is cured in stages with controlled temperature and humidity, the surface is polished to complete the preparation.

6. The method for preparing the cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties according to claim 5, characterized in that: In the raw material processing step, the modified closed-cell perlite is prepared as follows: the closed-cell perlite is dried at 100-105℃ for 3-4 hours until the water content is ≤0.5%, cooled, and then immersed in a 5-8% concentration of silane coupling agent KH-550 ethanol solution. The mixture is stirred at 80-90℃ and 300-400rpm for 2-3 hours, filtered, and then dried at 110-120℃ for 1.5-2 hours. The amount of silane coupling agent KH-550 used is 0.8-1.2% of the mass of the closed-cell perlite. The preparation of the epoxy-modified basalt fiber is as follows: basalt fiber is cut to 6-10 mm, rinsed, and then soaked in 3-5% sodium hydroxide solution at room temperature for 30-40 min. After activation, it is rinsed until neutral and dried. Then it is soaked in 10-15% epoxy resin ethanol solution at room temperature for 1-1.5 h and cured at 120-130℃ for 2-2.5 h.

7. The method for preparing the cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties according to claim 5, characterized in that: In the raw material processing step, the preparation of the urea-formaldehyde resin-coated epoxy resin microcapsules is as follows: epoxy resin is melted at 55-65℃ and then added to an aqueous solution containing 0.5-1.0% Tween-80. The mixture is stirred at 1000-1200 rpm for 30-40 min to form an emulsion. Urea-formaldehyde resin prepolymer is added, the pH is adjusted to 4.0-4.5, and the mixture is kept at 50-60℃ and stirred at 500-600 rpm for 2-3 h. After cooling, the mixture is washed and dried. The solid content of the urea-formaldehyde resin prepolymer is 60-65%, and the number average molecular weight is 1000-2000 Da. The preparation of the polycaprolactone diol modified polyurethane prepolymer is as follows: polycaprolactone diol and MDI are mixed at a molar ratio of 1:2, stirred and reacted under nitrogen protection at 80-90℃, and 0.1-0.2% dibutyltin dilaurate is added until the NCO content is 8.5-9.5%.

8. The method for preparing the cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties according to claim 5, characterized in that: In the interface preparation step, the mixing involves sequentially stirring the aqueous epoxy resin emulsion, polyurethane elastomer emulsion, and carboxylated styrene-butadiene rubber latex at 500-600 rpm for 10-15 min, then adding fumed silica, silane coupling agent KH-560, and urea-formaldehyde resin-coated epoxy resin microcapsules, and continuing to stir at 500-600 rpm for 15-20 min, followed by adding a polyamide curing agent and stirring at 300-400 rpm for 8-10 min. The stirring and curing process involves standing at room temperature for 15-20 min. In the skeleton treatment step, the sandblasting pressure for rust removal is 0.4-0.6MPa, the sandblasting time is 5-8min, the coating thickness of the epoxy zinc-rich primer is 80-100μm, the coating thickness of the interface buffer binder is 0.8-1.2mm, and the coating is left at room temperature for 30-40min.

9. The method for preparing the cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties according to claim 5, characterized in that: In the filler preparation step, the mixing involves stirring low-alkali cement, metakaolin, modified closed-cell perlite, and hollow glass microspheres at 800-1000 rpm for 15-20 minutes, then adding epoxy-modified basalt fiber, graphene oxide, nano-silica, and composite anti-aging agent, and stirring at 800-1000 rpm for 20-25 minutes. Next, redispersible latex powder, polycarboxylate-based high-efficiency water-reducing agent, and defoamer are added, and after stirring for 5-8 minutes, deionized water accounting for 12-18% of the total mass of the mixture is added, and the mixture is stirred at 600-800 rpm for 25-30 minutes. Subsequently, polycaprolactone diol-modified polyurethane prepolymer is added, and the mixture is stirred at 500-600 rpm for 8-10 minutes. Then, phase change microcapsules, urea-formaldehyde resin-coated epoxy resin microcapsules, and amine latent curing agent are added, and the mixture is stirred at 300-400 rpm for 5-10 minutes. In the filling and molding step, the injection pressure is 0.3-0.5MPa, the injection speed is 5-8L / min, the vibration venting frequency is 50-60Hz, the time is 5-8min, and the initial curing is allowed to stand at room temperature for 22-26h.

10. The method for preparing the cold-formed thin-walled steel lightweight polymer composite wall panel with both crack resistance and thermal insulation properties according to claim 5, characterized in that: In the maintenance process, the phased temperature and humidity control maintenance includes 7 days of maintenance at 20-25℃ and 80-90% humidity, followed by 14 days of maintenance at 60-70% humidity. On the 15th to 21st day of maintenance, the temperature is raised to 50-55℃ and kept at that temperature for 3-4 hours. After the surface is polished, the surface flatness is ≤3mm / m, and the surface is stored at an ambient temperature of 15-25℃, relative humidity ≤60%, and storage period ≤12 months.

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