Foldable and expandable modular prefabricated building product

Abstract

The invention relates to a foldable and expandable modular prefabricated building product. The foldable and expandable modular prefabricated building product comprises a plurality of building module units in groups. The adjacent building module units are connected in a foldable mode through the flexible connecting belts made of the high-elasticity resin base materials, and flexible folding and unfolding functions are provided. The expansion connecting face of each building module unit is provided with a multi-layer functional coating structure which sequentially comprises a base body combining layer, a deformation buffering layer, a waterproof sealing layer and a stress transmission layer. The base body bonding layer ensures firm bonding of the functional coating and the module units; the deformation buffer layer disperses external force through controllable deformation, so that stress concentration is avoided, and the adaptability of a connection interface is improved; the waterproof sealing layer forms a compact structure through molecular chain rearrangement, and excellent waterproof performance is achieved under the action of prestress; and the stress transfer layer is used for transferring and uniformly distributing prestress, so that the structural stability of expansion connection is enhanced. According to the modular building product, the comprehensive requirements of convenient transportation, rapid building and reliable connection are met.

Description

Technical Field

[0001] The invention relates to the technical field of prefabricated buildings, and in particular to a foldable and expandable modular prefabricated building product. Background Art

[0002] In the existing technology, modular prefabricated building products have been widely used in the construction industry, with the advantages of fast installation, convenient transportation and reusability. These products are usually based on standardized modular units, and multiple modules are combined into a whole through mechanical connection, welding or rigid connection to meet the needs of various construction scenarios. The application of modular buildings covers many fields such as temporary buildings, residential buildings, commercial facilities, etc.

[0003] Although existing modular building products have met the needs of use to a certain extent, there are still many problems that need to be solved. First, it is difficult for traditional connection methods to strike a balance between flexibility and reliability. Especially when the module units are folded, expanded or frequently used, the rigid connection is prone to damage or fatigue failure due to stress concentration, while the mechanical connection method may increase the construction difficulty and cost due to the complex structure. Secondly, the waterproof performance and environmental adaptability of the module connection interface materials are weak. When faced with long-term high humidity, extreme temperatures or external loads, the sealing performance is prone to decline, resulting in the durability and safety of the overall structure being affected. In addition, the existing products have uneven stress distribution during the connection process and lack effective stress buffering design, which further limits the expansion applicability of modular buildings and affects their reliability in harsh environments.

[0004] Therefore, it is necessary to develop an improved modular prefabricated building product to overcome the above-mentioned problems in the prior art. Summary of the invention

[0005] The present application provides a foldable and expandable modular prefabricated building product to achieve flexible folding and expansion of module units and improve transportation and installation efficiency.

[0006] The present application provides a foldable and expandable modular prefabricated building product, comprising a plurality of grouped building module units, wherein the grouped building module units include at least two building module units, and adjacent building module units are foldably connected by a flexible connecting belt, and the flexible connecting belt is made of a high-elasticity resin substrate;

[0007] The extended connection surface of each building module unit includes a multi-layer functional coating structure, and the multi-layer functional coating structure is used to realize the extended connection between the first group of building module units and the second group of building module units; the multi-layer functional coating structure includes a substrate bonding layer, a deformation buffer layer, a waterproof sealing layer and a stress transfer layer from the inside to the outside;

[0008] Among them, the substrate bonding layer is used to achieve a firm bond between the functional coating and the building module unit; the deformation buffer layer is used to produce controllable deformation when the first group of building module units and the second group of building module units are subjected to external force, so as to avoid stress concentration and improve the adaptability of the connection interface; the waterproof sealing layer is used to form a dense waterproof structure through molecular chain rearrangement under the action of the prestress, so as to ensure the waterproof performance of the extended connection; the stress transfer layer is used to transfer and evenly distribute the prestress between the first group of building module units and the second group of building module units, so as to ensure the structural stability of the extended connection.

[0009] Furthermore, the high-elastic resin substrate of the flexible connecting belt includes a reinforcing fiber material, which is selected from one of aramid fiber, carbon fiber or glass fiber, and the reinforcing fiber material is embedded along the longitudinal direction of the flexible connecting belt to form a multi-layer composite structure; the thickness of the flexible connecting belt ranges from 0.5 mm to 5 mm, and the content of the reinforcing fiber accounts for 5% to 25% of the total weight of the connecting belt; the surface of the flexible connecting belt is coated with a UV-resistant coating to improve the weather resistance under long-term exposure to sunlight.

[0010] Furthermore, the substrate bonding layer of the multi-layer functional coating structure includes nanoparticle filling materials to enhance the bonding force between the coating and the surface of the building module unit; the nanoparticles are selected from one or more of silicon oxide, titanium oxide or zinc oxide, and have an average particle size of 10 to 50 nanometers, and are distributed in the substrate bonding layer in a uniformly dispersed manner; the coating thickness of the substrate bonding layer is 50 to 200 microns, and is bonded to the surface of the building module unit substrate through plasma treatment or spraying technology, thereby ensuring that the adhesion performance of the functional coating is not affected under high humidity and high temperature difference conditions.

[0011] Furthermore, the deformation buffer layer includes a polymer-based material with shape memory function, and the polymer-based material is used to generate adaptive deformation when the ambient temperature changes, so as to further improve the connection adaptability between the module units; the thickness of the deformation buffer layer ranges from 0.1mm to 1mm, and its impact resistance and deformation recovery performance are further optimized by embedding micro-nano elastic particles or porous network structures.

[0012] Furthermore, the waterproof sealing layer adopts a multi-component interpenetrating network structure, which is formed by a cross-linking reaction of polyurethane, silicone rubber and acrylate materials; the multi-component interpenetrating network structure can quickly adjust the molecular arrangement when subjected to external pressure or stress through the dynamic rearrangement mechanism of the molecular chain, thereby realizing a dynamic self-repairing waterproof function; the waterproof sealing layer has a thickness ranging from 0.2 mm to 2 mm, and its surface has a nano-scale hydrophobic coating with a contact angle greater than 120 degrees, thereby improving the waterproof performance.

[0013] Furthermore, the stress transfer layer includes a stress-conducting microstructure, which is a regularly arranged hexagonal groove array, wherein the depth of the hexagonal groove is 50 to 200 microns and the width is 100 to 500 microns; the arrangement direction of the hexagonal groove array is consistent with the prestress transfer direction, so as to realize multi-dimensional stress transfer; the material of the stress transfer layer is an anisotropic polymer composite material, and the elastic modulus in the prestress transfer direction is 2 to 5 times that in the vertical direction.

[0014] Furthermore, the building module unit adopts a composite wall structure, including an outer high-strength frame and an inner lightweight filler; wherein the outer high-strength frame is made of carbon fiber reinforced epoxy resin, and the frame thickness is 30 to 50 mm; the inner lightweight filler is made of modified expanded clay concrete.

[0015] Furthermore, a stress sensing element is provided inside the flexible connecting belt. The stress sensing element is made of a conductive polymer doped with graphene, and its resistance value changes when the connecting belt is deformed. The stress sensing elements are evenly arranged along the length direction of the connecting belt with a spacing of 50 to 100 mm, and are used to monitor the stress distribution state during the folding process in real time.

[0016] Furthermore, a barrier coating is provided between the deformation buffer layer and the waterproof sealing layer in the multi-layer functional coating structure, and the thickness of the barrier coating is 10 to 50 microns; the barrier coating is made of a chemically resistant fluorocarbon polymer material.

[0017] Furthermore, the multilayer functional coating structure has phase change characteristics under pressure, specifically including: a microcapsule structure is distributed in the deformation buffer layer, the shell layer of the microcapsule structure is made of polymethyl methacrylate, and the interior is filled with temperature-sensitive phase change material and pressure-responsive catalyst; when the extended connection surfaces of the two module units are in contact under a predetermined pressure, some of the microcapsules are ruptured, the phase change material and the catalyst are mixed and chemically reacted to generate a new polymer with a cross-linked network structure, and the new polymer penetrates into the microstructure of the stress transfer layer to form a synergistic enhancement effect.

[0018] The beneficial effects of the technical solution provided by this application include:

[0019] (1) The present invention connects adjacent module units through flexible connecting belts, so that modular building products have the characteristics of foldability and expandability, which greatly reduces the space occupied during transportation, reduces transportation costs, simplifies on-site assembly operations, and improves construction efficiency. (2) By setting up a multi-layer functional coating structure, the deformation buffer layer therein can effectively alleviate the stress concentration caused by external forces, reduce the risk of damage to the connection interface, and improve the adaptability and long-term reliability of the module units in complex environments. (3) The waterproof sealing layer forms a dense waterproof structure through molecular chain rearrangement, ensuring that the expansion connection has excellent waterproof performance, effectively avoiding rainwater penetration or other humid environments on the overall performance of the building, and is suitable for building requirements under harsh environmental conditions. (4) The stress transfer layer can evenly distribute prestress between module units, reduce connection failures caused by local stress unevenness, ensure the overall structural stability of the expansion connection, and improve the reliability of the building under high load or dynamic load. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of a foldable and expandable modular prefabricated building product provided in the first embodiment of the present application.

[0021] Figure 2 It is a folding schematic diagram of a foldable and expandable modular prefabricated building product provided in the first embodiment of the present application.

[0022] Figure 3 It is an expanded schematic diagram of a foldable and expandable modular prefabricated building product provided in the first embodiment of the present application. DETAILED DESCRIPTION

[0023] Many specific details are described in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present application, so the present application is not limited by the specific implementation disclosed below.

[0024] The first embodiment of the present application provides a foldable and expandable modular prefabricated building product. Figure 1 , which is a schematic diagram of the first embodiment of the present application. Figure 1 A first embodiment of the present application provides a foldable and expandable modular prefabricated building product which is described in detail.

[0025] Figure 1 A set of building module units 100 is provided, Figure 2 Provided Figure 1 A schematic diagram of a group of building module units when folded is provided, Figure 3Provided are schematic diagrams of multiple groups of building module units 100, 200 and 300. The group of building module units includes building module units 101, 102 and 103, adjacent building module units 101 and 102 are foldably connected via a flexible connection belt 110, and adjacent building module units 102 and 103 are foldably connected via a flexible connection belt 111. It should be noted that Figure 1 The grouped building module units can also be expanded with more building module units and flexible connecting belts.

[0026] The front facade of the building module unit 101 has an extended connection surface 120. Similarly, the front facade of the building module unit 101 has an extended connection surface 121, and the front facade of the building module unit 103 has an extended connection surface 122. These extended connection surfaces can realize the splicing of different groups of building module units. It should be noted that the rear facades of the building module units 101-103 can also have corresponding extended connection surfaces.

[0027] The foldable and expandable modular prefabricated building product provided in this embodiment has a structural feature of comprising a plurality of grouped building module units, each group comprising at least two adjacent building module units, which are foldably connected by a flexible connecting belt. The flexible connecting belt adopts a highly elastic resin base material, which can be freely switched between the folded and unfolded states, while ensuring the mechanical properties and durability of the connection parts.

[0028] like Figure 1 As shown, the grouped building module units include building module units 101, 102 and 103. Adjacent module units are connected by flexible connecting belts 110 and 111. The core function of the flexible connecting belt is to provide flexible connection between module units, so that they can be compactly folded during transportation or storage, and quickly unfolded into a complete structure during on-site construction. The flexible connecting belt is made of a highly elastic resin substrate, preferably polyurethane, silicone or thermoplastic elastomer. These materials have excellent fatigue resistance, weather resistance and anti-aging properties, and can maintain stable performance after repeated folding and long-term use. The design of the connecting belt must ensure sufficient strength and resilience under stress, while avoiding local cracking or breakage due to concentrated external force.

[0029] The front and rear facades of the building module unit are provided with expansion connection surfaces, such as 120, 121 and 122. The expansion connection surface is a multi-layer functional coating structure, which includes a substrate bonding layer, a deformation buffer layer, a waterproof sealing layer and a stress transfer layer from the inside to the outside. Each layer is carefully designed and optimized to meet different functional requirements and ensure the reliability of the overall connection.

[0030] The substrate bonding layer is located at the innermost layer of the extended connection surface. Its function is to firmly attach the functional coating to the substrate surface of the building module unit. The selection of the substrate bonding layer should be optimized according to the substrate type of the module unit. For example, when the substrate of the module unit is concrete, a modified epoxy resin adhesive can be selected; if the substrate is metal, a polyurethane resin or silane-modified polymer with excellent adhesion can be used. The construction of the bonding layer must ensure uniform coverage of the entire extended connection surface, while avoiding the reduction of bonding strength caused by construction defects.

[0031] The deformation buffer layer is an external functional layer of the substrate bonding layer. Its main function is to disperse external forces and produce controllable deformation at the connection interface, thereby reducing stress concentration and improving the durability and adaptability of the connection. The buffer layer material is preferably an elastic polymer with low elastic modulus and good toughness, such as a polymer composite material embedded with micron-sized rubber particles, or a polyurethane material with shape memory properties. These materials can buffer impact loads through their own deformation when subjected to force, and quickly return to their original state after the external force disappears.

[0032] The waterproof sealing layer is located in the third layer of the functional coating. Its core function is to form a dense waterproof structure at the connection interface, thereby effectively blocking water penetration. This layer improves the sealing performance under the action of prestress through the rearrangement mechanism of the molecular chain. The material can be selected from silicone, polyurethane or butyl rubber with reversible cross-linking properties. These materials can rearrange their molecular structure when compressed by external force to form a continuous waterproof membrane. During the construction process, care should be taken to prevent local insufficient thickness or uneven coating to avoid a decrease in sealing performance.

[0033] As the outermost functional coating, the stress transfer layer is used to transfer and evenly distribute the prestress between the module units to ensure the mechanical stability of the entire expansion connection. The stress transfer layer is usually made of high-strength fiber-reinforced composite materials or metal films, such as carbon fiber composite materials or stainless steel films. These materials can maintain their stiffness and strength under high load conditions, while avoiding local instability or damage of the connection interface through optimized design.

[0034] The design of the flexible connection belt and the multi-layer functional coating needs to work together to achieve efficient folding, rapid splicing and stable connection between the module units. During the construction process, precise positioning can be used to ensure that the flexible connection belt is aligned with the extended connection surface, while the construction process of the multi-layer functional coating, including coating thickness, curing time and interface adhesion, is strictly controlled to ensure that the function of each layer is fully realized.

[0035] Furthermore, the high-elastic resin substrate of the flexible connecting belt includes a reinforcing fiber material, which is selected from one of aramid fiber, carbon fiber or glass fiber, and the reinforcing fiber material is embedded along the longitudinal direction of the flexible connecting belt to form a multi-layer composite structure; the thickness of the flexible connecting belt ranges from 0.5 mm to 5 mm, and the content of the reinforcing fiber accounts for 5% to 25% of the total weight of the connecting belt; the surface of the flexible connecting belt is coated with a UV-resistant coating to improve the weather resistance under long-term exposure to sunlight.

[0036] The flexible connecting belt provided in this embodiment has the characteristics of both flexibility and high strength by adding reinforcing fiber material to the high elastic resin substrate, and is suitable for connecting adjacent building module units to meet the performance requirements of modular prefabricated buildings in multiple folding, unfolding and long-term use. The reinforcing fiber material is preferably one of aramid fiber, carbon fiber or glass fiber, which are widely used for their excellent mechanical properties and durability. Among them, aramid fiber has extremely high tensile strength and impact resistance, carbon fiber is known for its light weight, high strength and good fatigue resistance, and glass fiber has high cost-effectiveness and excellent chemical corrosion resistance.

[0037] The reinforcing fiber material is embedded in the longitudinal direction of the flexible connecting belt to form a multi-layer composite structure. This design can significantly improve the tensile strength and fatigue resistance of the connecting belt while retaining the flexible characteristics required by the resin matrix. Specifically, the reinforcing fiber can be embedded in the resin matrix by continuous laying or fabric form, such as by pultrusion, hot pressing or spray molding, so that the fiber and the matrix are evenly integrated to form a stable multi-layer structure. In such a composite structure, the resin matrix is ​​mainly responsible for providing flexibility and weather resistance, while the reinforcing fiber enhances the tensile, tear and bending resistance.

[0038] The thickness of the flexible connection belt is designed to be 0.5mm to 5mm to balance strength and flexibility. When selecting the specific thickness, it can be adjusted according to the actual load requirements of the building module unit. For example, for lighter building modules, a thickness close to 0.5mm can be used to improve the flexibility of folding; for modules that bear higher loads, it is recommended to use a thickness close to 5mm to ensure that it does not break or permanently deform when unfolded and stressed. The content of reinforcing fiber is controlled at 5% to 25% of the total weight of the connection belt. The fiber ratio within this range can provide sufficient mechanical properties without affecting the flexibility and molding process of the resin substrate too much. For example, when the flexible connection belt is used to connect high-load modules, a reinforcing fiber content of up to 25% can be selected; for medium and low load applications, a fiber content of 5%-10% can be selected to reduce costs.

[0039] In order to ensure the performance stability of the flexible connecting belt under long-term exposure to sunlight or harsh environmental conditions, a layer of UV-resistant coating is coated on its surface. The main function of this coating is to prevent UV rays from degrading the resin substrate, while improving its weather resistance and anti-aging properties. The coating material is preferably a polyurethane coating with high light stability and strong adhesion, a fluorocarbon coating, or a silicone coating with added UV absorbers, which can maintain a long service life in a high UV environment. The coating process can be sprayed, rolled or dipped, and the coating thickness is controlled between 10 and 50 microns to ensure its effective shielding effect on UV rays, while avoiding the influence of too thick a coating on the bending performance of the flexible connecting belt. For example, when the flexible connecting belt is used in an environment with high altitude or strong UV radiation, a thicker coating design can be used; for indoor applications, a thinner coating can be used to reduce manufacturing costs.

[0040] Through the implementation of the above-mentioned reinforcing fibers, multi-layer composite structure and UV-resistant coating, the flexible connecting belt has excellent tensile strength, weather resistance and long-term use reliability while meeting the basic connection function.

[0041] In this embodiment, in order to meet the performance requirements of the flexible connecting belt in different application scenarios, while taking into account the material cost and the operability of the manufacturing process, the following implementation scheme can also be adopted, involving the selection of reinforcing fiber materials, the mixing ratio and the detailed steps of the manufacturing process, as follows:

[0042] In the specific design, the reinforcing fiber material of the flexible connection belt adopts a combination of aramid fiber, carbon fiber and glass fiber, and the proportion is set as follows: aramid fiber accounts for 15% of the total weight of the reinforcing fiber, carbon fiber accounts for 70%, and glass fiber accounts for 15%. This proportion is designed with comprehensive consideration of the mechanical properties and durability of various types of fibers: aramid fiber provides excellent impact resistance, carbon fiber provides high strength and light weight, and glass fiber is used to enhance corrosion resistance and reduce overall costs.

[0043] The thickness of the flexible connection belt is set to 3mm to achieve a balance between flexibility and strength. The reinforcing fibers are embedded in the resin matrix to form a three-layer composite structure: the outermost layer is a 0.5mm thick glass fiber reinforcement layer, the middle layer is a 2mm thick carbon fiber main load-bearing layer, and the innermost layer is a 0.5mm thick aramid fiber buffer layer. This layered structural design ensures that under various stresses, the connection belt can provide high-strength support and effectively relieve stress concentration when external forces impact.

[0044] During the manufacturing process, the embedding of reinforcing fibers is achieved through the following steps: First, the three fiber materials are configured according to the above proportions, and high-precision fiber placement equipment is used to arrange the fibers in layers in the mold. Secondly, polyurethane with an elastic modulus of 30MPa is selected as the resin matrix, and it is evenly injected into the mold to ensure complete infiltration between the fiber and the matrix. Subsequently, a high-temperature hot pressing process is used to pressurize the mold at 150°C for 3 hours to fully cure the resin and form a stable composite structure. Finally, the cured flexible connecting belt is cut into the required size by CNC cutting equipment, such as a standardized connecting belt with a length of 500mm and a width of 50mm.

[0045] To improve the weather resistance of the flexible connecting belt, a layer of UV-resistant coating is applied on its surface. The coating is made of polyurethane-based light-stable material with a thickness of 20 microns, and is evenly coated on the surface of the connecting belt through a spraying process. The coated flexible connecting belt can maintain its mechanical properties and flexibility under long-term UV irradiation without obvious aging or performance degradation.

[0046] The final flexible connection belt has a tensile strength of more than 98% after 5,000 folding and unfolding cycles, and no obvious fatigue damage; in the environmental aging test simulating exposure to sunlight for 365 days, its surface coating is intact and the internal reinforcement structure remains intact. Through precise material ratio, layered design and manufacturing process, the flexible connection belt has high strength, weather resistance and flexibility, and can be applied to the connection needs of various modular building products.

[0047] Furthermore, the substrate bonding layer of the multi-layer functional coating structure includes nanoparticle filling materials to enhance the bonding force between the coating and the surface of the building module unit; the nanoparticles are selected from one or more of silicon oxide, titanium oxide or zinc oxide, and have an average particle size of 10 to 50 nanometers, and are distributed in the substrate bonding layer in a uniformly dispersed manner; the coating thickness of the substrate bonding layer is 50 to 200 microns, and is bonded to the surface of the building module unit substrate through plasma treatment or spraying technology, thereby ensuring that the adhesion performance of the functional coating is not affected under high humidity and high temperature difference conditions.

[0048] The substrate bonding layer of this embodiment is designed to significantly enhance the bonding strength between the multi-layer functional coating structure and the surface of the building module unit, thereby ensuring the reliability and durability of modular buildings in various complex environments. The substrate bonding layer introduces nanoparticle filling materials, which can enhance the adhesion of the coating to the substrate through various mechanisms, while providing additional physical and chemical stability.

[0049] In a specific implementation, the nanoparticles in the substrate bonding layer are selected from one or more of silicon oxide (SiO2), titanium oxide (TiO2) or zinc oxide (ZnO). These materials are widely used in the field of functional coatings due to their high surface energy, small particle size and good chemical inertness. In the present invention, the average particle size of the nanoparticles is designed to be 30 nanometers to ensure that they can be evenly dispersed in the substrate bonding layer, thereby maximizing the adhesion and filling effect of the coating.

[0050] The preparation process of the matrix bonding layer includes the dispersion of nanoparticles and the molding of the coating. First, the selected nanoparticles are mixed with the polymer matrix material according to the designed proportion (accounting for 3% of the total mass of the coating), and the polymer matrix can be epoxy resin or polyurethane resin. In order to ensure the uniform dispersion of the nanoparticles, an appropriate amount of dispersant (such as polycarboxylate or silane coupling agent) can be added, and the mixture is treated with a high shear stirring device or an ultrasonic dispersion device until a uniform nanoparticle dispersion is formed. Subsequently, the dispersion is evenly coated on the surface of the building module unit through a spraying device, and the coating thickness is strictly controlled at 100 microns to ensure that it can provide sufficient bonding strength without affecting the construction of subsequent functional coatings.

[0051] Before coating, in order to further improve the adhesion between the base bonding layer and the substrate surface, the surface of the building module unit can be treated with plasma or mechanical sandblasting. Plasma treatment activates the molecular bonds on the surface of the substrate to form a high-energy active surface, thereby enhancing the bond between the substrate and the coating; mechanical sandblasting increases the adhesion area by increasing the surface roughness. These pre-treatment technologies can effectively remove the oil or oxide layer on the surface of the substrate and ensure that the base bonding layer is tightly bonded to the substrate surface.

[0052] After coating, the substrate bonding layer is heated or cured at room temperature to form a stable adhesion layer. For example, the coated module unit is placed in an environment of 80°C for 3 hours to ensure that the mechanical properties of the coating are optimal. At this time, the presence of nanoparticles can significantly improve the adhesion strength of the coating through the dual mechanisms of physical intercalation and chemical bonding. In high humidity and high temperature difference environments, such as exposure to continuous humid rainy seasons or areas with a temperature difference of more than 30°C between day and night, the coating can still maintain excellent adhesion properties without peeling or cracking.

[0053] Through this design and preparation process, the substrate bonding layer can meet the stringent requirements of the building environment. For example, in actual tests, after the module unit coated with the nanoparticle substrate bonding layer was immersed in a high humidity environment of 90% for 72 hours, the adhesion strength of the coating decreased by less than 5%. At the same time, in the hot and cold cycle test (a total of 200 cycles from -20°C to 60°C), the coating did not show any obvious peeling or cracking.

[0054] The design of the base bonding layer and the preparation method thereof of this embodiment provide a strong guarantee for the high-performance connection of modular buildings.

[0055] This embodiment also provides the following specific composition and preparation method of the substrate bonding layer, so as to achieve high bonding strength between the functional coating and the building module unit.

[0056] The specific formula of the substrate bonding layer is as follows: the substrate material uses epoxy resin as the main component, which accounts for 70% of the total weight of the substrate bonding layer. The nanoparticle filler material for enhancing adhesion is a mixture of silicon oxide (SiO2), titanium oxide (TiO2) and zinc oxide (ZnO) in a weight ratio of 40:40:20, and the total amount of nanoparticles added is 10% of the total weight of the substrate bonding layer. In addition, to ensure the uniform dispersion of the nanoparticles, a silane coupling agent (such as γ-aminopropyltriethoxysilane) with a mass fraction of 2% is added as a dispersant, and xylene with a mass fraction of 18% is added as a diluent to adjust the construction viscosity of the coating.

[0057] The method for preparing the substrate bonding layer comprises the following steps:

[0058] (1) Mixing and dispersion of nanoparticles:

[0059] After the silicon oxide, titanium oxide and zinc oxide nanoparticles prepared in the above proportions are mixed evenly, they are added to xylene and treated with an ultrasonic dispersion device for 30 minutes to make the nanoparticles evenly distributed in the solvent. Subsequently, the silane coupling agent is slowly added to the dispersion and stirred continuously at room temperature for 15 minutes to ensure that the coupling agent has a sufficient chemical reaction with the surface of the nanoparticles and improve the compatibility of the particles with the matrix resin.

[0060] (2) Preparation of matrix material:

[0061] The epoxy resin was heated to 40°C under stirring conditions, and then the prepared nanoparticle dispersion was slowly added to the epoxy resin while maintaining the stirring speed at 300 revolutions per minute. After the addition was completed, stirring was continued for 30 minutes until the mixture was in a uniform slurry.

[0062] (3) Coating and curing:

[0063] Before coating, the surface of the building module unit is plasma treated, using a plasma device at 100W power for 2 minutes to form highly active binding sites on the substrate surface. Then, the prepared substrate bonding layer material is evenly coated on the surface of the building module unit by a spraying device, and the coating thickness is controlled to be 100 microns. After coating, the module unit is placed in an environment of 80°C for 2 hours to cure the coating completely.

[0064] The prepared substrate bonding layer showed excellent adhesion performance in the test. After immersion in 90% relative humidity for 72 hours, the adhesion strength test result was 8MPa, which was 50% higher than the substrate material without nanoparticles. In the hot and cold cycle test (200 cycles from -20°C to 60°C), the coating did not peel, bubble or crack.

[0065] By providing the material proportions and process steps in this embodiment, the technical solution can be directly implemented to prepare a high-performance substrate bonding layer and ensure its reliability and stability in a complex building environment.

[0066] Furthermore, the deformation buffer layer includes a polymer-based material with shape memory function, and the polymer-based material is used to generate adaptive deformation when the ambient temperature changes, so as to further improve the connection adaptability between the module units; the thickness of the deformation buffer layer ranges from 0.1mm to 1mm, and its impact resistance and deformation recovery performance are further optimized by embedding micro-nano elastic particles or porous network structures.

[0067] In this embodiment, the main component of the deformation buffer layer is a polyurethane-based shape memory polymer (SMPU), which has excellent shape memory properties and adaptive deformation capabilities. The polyurethane-based material is endowed with temperature responsiveness through the cross-linked structure of the molecular chain, and can achieve shape change and recovery according to the preset transition temperature (Tg) when the ambient temperature changes. The Tg selected in the material is set to 35°C, which is a temperature range suitable for natural temperature difference conditions in most building scenarios.

[0068] The specific formula of the deformation buffer layer is: shape memory polyurethane accounts for 80% of the total weight of the deformation buffer layer, micro-nano elastic particles account for 15%, and porous network structure pore formers account for 5%. Micro-nano elastic particles are spherical silicone rubber particles with an average diameter of 200 nanometers. After adding, they can increase the local elastic modulus of the deformation buffer layer and enhance its impact resistance. The porous network structure is achieved by adding pore formers (such as polyethylene glycol) during the curing process, and the pore size is controlled at 50 to 100 microns to improve the flexibility and deformation recovery ability of the material.

[0069] The preparation method is as follows: First, according to the above formula ratio, the polyurethane shape memory polymer is mixed with the silicone rubber particles, and a high-speed shear mixer is used to stir at a speed of 500 revolutions per minute for 30 minutes to ensure that the particles are evenly distributed in the polymer matrix. Subsequently, 5% of the pore-forming agent is added and stirred continuously at 60°C for 15 minutes to fully mix the pore-forming agent. After the mixing is completed, the material is injected into the mold and cured at 80°C for 2 hours, and then post-cured at 120°C for 1 hour to achieve the final optimization of mechanical properties.

[0070] The thickness of the deformation buffer layer is precisely controlled to 0.5 mm. The material is evenly coated on the substrate bonding layer of the multi-layer functional coating structure through a micro-coating device to ensure good adhesion between it and the upper and lower coatings. The cured deformation buffer layer has the following characteristics: when the ambient temperature is higher than Tg, the polyurethane substrate becomes soft and can adjust its shape according to external pressure to adapt to the stress distribution of the connection interface; when the temperature is lower than Tg, the material returns to its original state, thereby providing stable support at the connection interface.

[0071] In the impact resistance test, the prepared deformation buffer layer showed no cracks or permanent deformation after withstanding an impact energy of 10J, and the recovery rate reached over 95%. In the hot and cold cycle test (100 cycles from -20°C to 60°C), the shape memory properties of the material remained stable, and no performance degradation occurred. In practical applications, the deformation buffer layer effectively alleviates the stress concentration caused by external forces between module units, and improves the adaptability of the connection interface and the reliability of long-term use.

[0072] Through the above-mentioned formula and process description, a deformation buffer layer can be implemented to prepare a buffer layer with shape memory function and excellent performance, thereby meeting the multiple requirements of modular buildings for flexibility, durability and environmental adaptability.

[0073] Furthermore, the waterproof sealing layer adopts a multi-component interpenetrating network structure, which is formed by a cross-linking reaction of polyurethane, silicone rubber and acrylate materials; the multi-component interpenetrating network structure can quickly adjust the molecular arrangement when subjected to external pressure or stress through the dynamic rearrangement mechanism of the molecular chain, thereby realizing a dynamic self-repairing waterproof function; the waterproof sealing layer has a thickness ranging from 0.2 mm to 2 mm, and its surface has a nano-scale hydrophobic coating with a contact angle greater than 120 degrees, thereby improving the waterproof performance.

[0074] The waterproof sealing layer in this embodiment forms a multi-component interpenetrating network (IPN) structure through the cross-linking reaction of polyurethane, silicone rubber and acrylate materials. The material ratio is set as follows: polyurethane accounts for 50% of the total weight of the sealing layer, silicone rubber accounts for 30%, and acrylate accounts for 20%. Polyurethane provides excellent elasticity and durability, silicone rubber gives the material flexibility and anti-aging properties, and acrylate enhances the strength and chemical stability of the network structure. The interpenetrating network structure of the material is achieved through a multi-component cross-linking reaction, in which the dynamic molecular chain rearrangement mechanism enables the molecular chain segments to quickly adjust their arrangement when the material is subjected to external pressure or stress, thereby forming a self-repairing waterproof barrier at the interface.

[0075] The preparation of the waterproof sealing layer includes the following steps: First, the polyurethane precursor and the silicone rubber matrix are mixed in a mass ratio of 5:3, and 1% of a catalyst (such as dibutyltin dilaurate) is added to promote the cross-linking reaction of the polyurethane. Subsequently, acrylate monomers (20% by mass) and 2% of an initiator (such as dibenzoyl peroxide) are added to initiate the free radical polymerization reaction of the acrylate. During the mixing process, the mixture is stirred at a speed of 600 revolutions per minute for 30 minutes by a mechanical stirring device to ensure that the components are evenly dispersed.

[0076] After mixing, the material is injected into the coating equipment, and the mixed material is evenly coated on the target surface through a spraying process, and the coating thickness is precisely controlled to 1 mm. Subsequently, the coated material is placed in an environment of 80°C for preliminary curing for 2 hours to complete the cross-linking reaction of polyurethane and acrylate. Then, the silicone rubber is completely cured at room temperature for 24 hours. The final waterproof sealing layer has a uniform interpenetrating network structure.

[0077] To further enhance the waterproof performance of the surface, the surface of the waterproof seal layer is coated with a nano-scale hydrophobic coating. The hydrophobic coating is made of modified fluorocarbon material, with a coating thickness of 20 nanometers and a contact angle greater than 120 degrees. The coating is prepared using a vacuum evaporation process to ensure uniformity and defect-free coverage during coating. The hydrophobic coating can effectively prevent the penetration of liquid water in long-term humid and water-immersed environments, further improving the overall waterproof effect.

[0078] The prepared waterproof sealing layer showed excellent performance in a variety of test environments. In the self-healing function test, after the coating was damaged by 10 artificial scratches with a diameter of 0.1 mm, the scratch area was completely closed within 2 minutes by applying a pressure of 1 MPa, and the water permeability recovered to more than 95% of the initial state. In the hydrophobic performance test, the water droplet rolling angle on the coating surface was 5°, showing excellent anti-water performance. In addition, after 100 hot and cold cycles (-40°C to 80°C) and 1000 hours of UV aging, the waterproof layer did not show obvious cracking or performance degradation, proving its long-term reliability in harsh environments.

[0079] Through the above-mentioned material ratios, preparation processes and test results, the technical solution for the waterproof sealing layer can be implemented to prepare a sealing layer with dynamic self-repairing and excellent waterproof performance, which can meet the use requirements of modular building products in various complex environments.

[0080] Furthermore, the stress transfer layer includes a stress-conducting microstructure, which is a regularly arranged hexagonal groove array, wherein the depth of the hexagonal groove is 50 to 200 microns and the width is 100 to 500 microns; the arrangement direction of the hexagonal groove array is consistent with the prestress transfer direction, so as to realize multi-dimensional stress transfer; the material of the stress transfer layer is an anisotropic polymer composite material, and the elastic modulus in the prestress transfer direction is 2 to 5 times that in the vertical direction.

[0081] The core of the stress transfer layer is the stress-conducting microstructure, which consists of a regularly arranged array of hexagonal grooves. These hexagonal grooves optimize the directionality and distribution uniformity of stress transfer through geometric design. The specific dimensions of the hexagonal grooves are set to a depth of 150 microns, a width of 300 microns, and a groove spacing of 100 microns. This size design balances the stress transfer efficiency and material strength of the structure, ensuring that the layer structure will not fail due to excessive local stress concentration under high prestress conditions. The arrangement direction of the hexagonal array is strictly consistent with the prestress transfer direction, so that stress can be effectively transferred in the predetermined direction.

[0082] The stress transfer layer material is a polymer composite material with anisotropic mechanical properties. The basic polymer matrix is ​​thermoplastic polyurethane (TPU), and the reinforcement material is oriented carbon fiber, which accounts for 30% of the total material weight. The carbon fiber is oriented in the prestress transfer direction through stretching orientation technology, so that the elastic modulus of the composite material in this direction is 4 times that of the vertical direction, thereby significantly improving the stress transfer efficiency.

[0083] The preparation method is as follows:

[0084] (1) Material preparation: First, thermoplastic polyurethane particles and chopped carbon fibers were mixed in a weight ratio of 70:30 and stirred at 180°C by a melt blending device at a stirring speed of 500 revolutions per minute for 20 minutes. Subsequently, the mixture was extruded into a sheet with a thickness of 500 μm by a twin-screw extruder and cooled for standby use.

[0085] (2) Hexagonal groove processing: Use laser etching technology to process hexagonal groove arrays on the surface of the thin film. The laser etching equipment parameters are set as follows: laser power is 10W, scanning speed is 100mm / s, etching depth is controlled to 150 microns, and the etching path is strictly arranged according to the geometric design of the hexagonal array. The groove array model is generated by computer-aided design (CAD) software, and the processing accuracy and consistency are ensured by CNC equipment.

[0086] (3) Composite layer molding: After the hexagonal groove processing is completed, the sheets are stacked to the target thickness (recommended to be 2 mm) and pressed by a hot press at 200°C. The hot pressing process lasts for 30 minutes and the pressure is set to 5 MPa to ensure the orientation stability of the carbon fibers and the overall density of the material.

[0087] The elastic modulus of the prepared stress transfer layer in the stress direction is 100MPa, while the elastic modulus in the vertical direction is 25MPa, achieving the design target of anisotropic mechanical properties. In the test, the layer was embedded in the connection interface of modular building products and loaded under 2000N prestress conditions. The results showed that the stress distribution of the connection interface was uniform, without local stress concentration or material damage.

[0088] In the multi-dimensional stress transfer test, the stress transfer layer's stress conduction capacity was verified by applying multi-directional loads. The results showed that the hexagonal groove array can effectively disperse stress in multiple directions, and the material did not suffer fatigue damage during the 50 load cycles tested, maintaining a stable stress transfer efficiency.

[0089] This stress transfer layer is suitable for scenarios in modular buildings that need to withstand high loads and have strict requirements on uniform stress distribution, such as the splicing interface of bridge modules or the stress nodes of high-rise buildings. At the same time, by adjusting the size and arrangement density of the hexagonal grooves, or changing the orientation ratio of the carbon fibers, the material properties can be further optimized to meet different engineering needs.

[0090] Furthermore, the building module unit adopts a composite wall structure, including an outer high-strength frame and an inner lightweight filler; wherein the outer high-strength frame is made of carbon fiber reinforced epoxy resin, and the frame thickness is 30 to 50 mm; the inner lightweight filler is made of modified expanded clay concrete.

[0091] The building module unit provided in this embodiment adopts a composite wall structure to achieve an optimized combination of high strength and light weight, thereby improving the strength, stability and construction convenience of modular prefabricated building products. The composite wall structure includes an outer high-strength frame and an inner lightweight filling body. Its design is based on precise material selection and structural optimization, and can meet the performance requirements in complex building scenes.

[0092] The outer high-strength frame is the main load-bearing part of the composite wall structure and is made of carbon fiber reinforced epoxy resin. Carbon fiber is the preferred material due to its extremely high specific strength and specific modulus, which can significantly improve the bending strength and impact resistance of the wall. Epoxy resin, as a matrix material, provides good bonding performance and durability, while its compatibility with carbon fiber ensures the overall mechanical properties of the composite material. The thickness of the outer frame is designed to be 40 mm. The choice of this thickness takes into account the balance between strength and weight, so that the wall can reduce the weight of the overall structure while ensuring sufficient rigidity. In order to achieve high-precision and high-strength production of the outer frame, the pultrusion process is used to composite the carbon fiber cloth with epoxy resin and then continuously molded. During the pultrusion process, the fiber arrangement direction and resin content are precisely controlled to ensure that the frame has uniform mechanical properties and stable dimensional accuracy.

[0093] The inner layer of lightweight filler is made of modified ceramsite concrete, which is used to provide the necessary thermal insulation and sound absorption performance without significantly increasing the weight of the wall. Ceramic aggregate concrete is a lightweight concrete with ceramsite as aggregate. Its excellent lightness and thermal properties make it an ideal material for modular building products. In the present invention, ceramsite concrete is specially modified to further improve its strength and durability. During the modification process, a layer of silicate-based material is coated on the surface of the ceramsite to enhance its interfacial bonding properties, and at the same time, 5% of fiber reinforcement materials (such as polypropylene fibers) and 8% of silica fume are added to the concrete slurry to significantly improve the compressive strength and toughness of the filler. The modified ceramsite concrete finally prepared has a compressive strength of 15MPa and a density of 1200kg / m 3 The excellent performance can not only effectively reduce the weight of the wall, but also meet the requirements of structural stability.

[0094] The forming process of the composite wall structure adopts a step-by-step assembly method. First, prepare the outer high-strength frame and ensure that its dimensional accuracy meets the design requirements. Then, the inner lightweight filler is filled into the frame through a pouring process. During this process, it is necessary to ensure that the filler and the frame are completely combined. To this end, a layer of epoxy resin adhesive with a thickness of 0.5 mm is coated on the inner surface of the frame, and the ceramsite concrete is poured before the adhesive is cured. After the filling is completed, the whole is placed in a steam curing room for 24 hours of wet heat curing. The curing temperature is controlled at 60°C to accelerate the solidification of the filler and the combination of the frame and the filler.

[0095] The formed composite wall has been tested for performance and has shown excellent mechanical and functional properties. In the compressive strength test, the composite wall can withstand a load of 100kN without significant deformation; in the bending test, the maximum deflection of the wall is less than 3 mm. In addition, the low thermal conductivity of ceramsite concrete (0.3W / m·K) gives the wall good thermal insulation performance, and the sound absorption performance of the porous structure further improves the acoustic comfort of the module unit.

[0096] The composite wall structure provided in this embodiment not only meets the requirements of modular building products for high strength and lightness, but also achieves significant optimization in terms of thermal insulation and sound absorption performance through the synergistic effect of a high-strength frame and a lightweight filler.

[0097] Furthermore, a stress sensing element is provided inside the flexible connecting belt. The stress sensing element is made of a conductive polymer doped with graphene, and its resistance value changes when the connecting belt is deformed. The stress sensing elements are evenly arranged along the length direction of the connecting belt with a spacing of 50 to 100 mm, and are used to monitor the stress distribution state during the folding process in real time.

[0098] The flexible connecting belt provided in this embodiment realizes real-time monitoring of stress distribution during folding and expansion by arranging stress sensing elements inside. This design not only enhances the intelligence level of modular prefabricated building products, but also provides a technical solution that can improve structural safety and service life. The stress sensing element is made of graphene-doped conductive polymer, and its structural design and functional realization are precisely optimized.

[0099] The core material of the stress sensing element is a graphene-doped polymer composite material. Polyvinylidene fluoride (PVDF) is selected as the polymer matrix because of its excellent flexibility and thermal stability, and it can maintain stable performance under a wide range of deformation conditions. The doping ratio of graphene is 5% of the total weight of the matrix material. By increasing the density and uniformity of the conductive network, a sensitive change in the resistance value when the stress changes is achieved. Graphene exists in the form of nanosheets with a size range of 1 to 5 microns, and is evenly dispersed in the polymer matrix by solution mixing. In order to ensure the dispersion stability of graphene in the matrix, 1% of a dispersant (such as polyvinyl pyrrolidone) is added during the mixing process, and it is processed by ultrasonic dispersion equipment until a uniform conductive slurry is formed.

[0100] The shape of the stress sensing element is designed as a slender strip of conductive film with a width of 1 mm and a thickness of 0.2 mm. It is evenly arranged along the length of the flexible connecting belt, and the spacing is precisely set to 75 mm to take into account the resolution and material cost of stress monitoring. Each sensing element is fixed inside the flexible connecting belt through a micro-embedding process, and its end electrodes are coated with silver paste and connected to the data acquisition system through a flexible circuit board. The embedding process uses multi-layer co-extrusion molding technology to embed the sensing element into the middle layer of the highly elastic resin substrate, thereby ensuring the sensor function while not affecting the overall mechanical properties and flexibility of the connecting belt.

[0101] The working principle of the sensor element is based on the change of the conductive path caused by strain. When the flexible connecting belt is deformed during folding or expansion, the conductive network inside the graphene-doped conductive polymer is adjusted due to the stress change, causing the resistance value of the sensor element to change accordingly. By monitoring the resistance change in real time, the stress distribution state of each part of the connecting belt can be accurately reflected. In order to achieve high-precision data collection, the output signal of the sensor element is transmitted to the external processing unit through the flexible circuit. The processing unit uses a bridge circuit and an amplifier for signal processing, and finally transmits the stress data to the monitoring system in the form of a digital signal.

[0102] After the prepared flexible connecting belt was equipped with an embedded stress sensing element, its performance was verified through actual testing. In the static tensile test, the sensing element showed a linear resistance response to a strain change of 0.1% to 10%, with a sensitivity of 3.5%. In the dynamic folding test, the flexible connecting belt was folded repeatedly 2,000 times, and the sensing element still maintained a stable response performance without obvious fatigue damage. In addition, in the environmental adaptability test, the output signal of the sensing element was stable and there was no drift under the temperature range of -20°C to 80°C.

[0103] Through this design, the flexible connecting belt not only realizes the function of real-time stress monitoring, but also maintains its original high elasticity and durability. In practical applications, this technology can provide important structural health monitoring capabilities for modular building products, and timely detect and warn potential stress concentration problems.

[0104] Furthermore, a barrier coating is provided between the deformation buffer layer and the waterproof sealing layer in the multi-layer functional coating structure, and the thickness of the barrier coating is 10 to 50 microns; the barrier coating is made of a chemically resistant fluorocarbon polymer material.

[0105] In the multi-layer functional coating structure provided in this embodiment, a barrier coating is provided between the deformation buffer layer and the waterproof sealing layer, and its design is intended to improve the overall chemical corrosion resistance and interlayer stability of the coating structure. The barrier coating achieves efficient isolation and protection through material selection and thickness control, and further optimizes the service life and reliability of the multi-layer functional coating structure, especially in complex chemical environments or long-term humid conditions.

[0106] The barrier coating is made of fluorocarbon polymer material. The preferred fluorocarbon polymer is polyvinylidene fluoride (PVDF) or its copolymer. Fluorocarbon polymer is selected as the main component of the barrier coating because of its extremely low surface energy, high chemical corrosion resistance and excellent anti-aging performance. This material can effectively block the migration of chemical substances between the deformation buffer layer and the waterproof sealing layer, and prevent performance degradation caused by interface penetration. At the same time, fluorocarbon polymer has excellent adhesion and can form a stable isolation layer without affecting the overall adhesion performance of the multilayer structure.

[0107] The thickness of the barrier coating is designed to be 30 microns, which is an optimal choice between performance and construction feasibility. A coating that is too thin may result in insufficient isolation effect, while a coating that is too thick may affect the flexibility and overall performance of the multilayer structure. The fluorocarbon polymer material is coated in the form of a solution, and its preparation process includes dissolving PVDF resin in dimethylacetamide (DMAC) solvent at a concentration of 20% (mass fraction). In order to improve the uniformity and adhesion of the coating, 1% of a surfactant (such as a fluorinated surfactant) can be added and treated with high-speed stirring and ultrasonic dispersion equipment for 30 minutes to make the solution uniform and stable.

[0108] The coating process uses a spraying method to evenly coat the prepared fluorocarbon polymer solution on the surface of the deformation buffer layer through a precision spraying device. During the coating process, ensure that the distance between the nozzle and the substrate surface is 150 mm and the spraying speed is 100 mm / s to achieve uniform coverage. After the coating is completed, the coating is placed in a 100°C environment for 20 minutes to evaporate the solvent and initially cure. Subsequently, a secondary heat treatment is performed at 150°C for 30 minutes to complete the complete curing of the coating and form a dense barrier layer.

[0109] The prepared multi-layer functional coating structure has been verified to have superior performance through actual performance testing. In the chemical corrosion resistance test, the barrier coating was able to maintain its integrity and isolation performance after being immersed in a 10% hydrochloric acid solution and a 5% sodium hydroxide solution for 72 hours, without any visible corrosion or discoloration. In the moisture and heat resistance test, after the sample was placed in an environment of 95% relative humidity and 60°C for 100 hours, there was no peeling or performance degradation between the coatings. Further adhesion tests showed that the bonding strength of the barrier coating with the upper and lower layers of materials reached 5MPa, meeting the actual use requirements.

[0110] By adding a barrier coating between the deformation buffer layer and the waterproof sealing layer, not only the chemical corrosion resistance of the multi-layer coating structure is improved, but also the stability and long-term reliability of the interface between the layers are enhanced.

[0111] Furthermore, the multilayer functional coating structure has phase change characteristics under pressure, specifically including: a microcapsule structure is distributed in the deformation buffer layer, the shell layer of the microcapsule structure is made of polymethyl methacrylate, and the interior is filled with temperature-sensitive phase change material and pressure-responsive catalyst; when the extended connection surfaces of the two module units are in contact under a predetermined pressure, some of the microcapsules are ruptured, the phase change material and the catalyst are mixed and chemically reacted to generate a new polymer with a cross-linked network structure, and the new polymer penetrates into the microstructure of the stress transfer layer to form a synergistic enhancement effect; wherein the average particle size of the microcapsules is 1 to 5 microns, and the mass percentage in the deformation buffer layer is 3% to 8%, and the shell strength of the microcapsules is achieved by regulating the wall thickness to ensure that it only ruptures within a predetermined pressure range.

[0112] The multi-layer functional coating structure provided in this embodiment introduces a microcapsule structure into the deformation buffer layer, giving the coating a phase change characteristic under pressure, so that it can achieve adaptive enhancement and interface optimization when the module unit is expanded and connected. This design not only improves the connection performance of the module unit, but also enhances the long-term reliability of the coating structure, ensuring that it can still maintain excellent functional performance after repeated use.

[0113] The design of the microcapsule structure is the core of achieving this phase change property. The shell of the microcapsule is made of polymethyl methacrylate (PMMA), which has good mechanical strength and controllable rupture characteristics, ensuring that it ruptures within a predetermined pressure range to release the active substances filled inside. The average particle size of the microcapsules is 3 microns, and this size range enables them to be evenly distributed in the deformation buffer layer while maintaining sufficient reactivity and permeability. In order to regulate the shell strength, the thickness of the microcapsule shell is set to 200 nanometers, which is precisely controlled by adjusting the concentration of the PMMA solution and the emulsification stirring speed in the microcapsule preparation.

[0114] The microcapsules are filled with temperature-sensitive phase change materials and pressure-responsive catalysts. The phase change materials are preferably paraffin compounds (such as n-octadecane), which have excellent energy storage performance and thermal stability and can achieve solid-liquid conversion within a specific temperature range. The catalyst is a two-component cross-linking reaction initiator (such as an organic peroxide), which can stimulate a chemical reaction under pressure to generate a new polymer with a cross-linked network structure. This polymer not only has excellent mechanical properties, but can also interact with the microstructure of the stress transfer layer to further improve the strength and stability of the connection interface.

[0115] The preparation process of the deformation buffer layer includes uniform dispersion of microcapsules and coating molding. First, 5% of the microcapsules by mass are mixed with the polyurethane matrix material and stirred at 500 rpm for 30 minutes by a high-speed shear stirring device to ensure that the microcapsules are evenly distributed in the matrix. Subsequently, the mixed material is evenly coated on the surface of the matrix bonding layer by a scraping process, and the coating thickness is precisely controlled to be 0.8 mm. After coating, the preliminary curing is carried out at an ambient temperature of 60°C for 2 hours, and then the secondary curing is carried out at 120°C for 4 hours to improve the mechanical properties of the coating and the distribution stability of the microcapsules.

[0116] During the expansion and connection process of the module unit, when the connection surface is subjected to a pressure of 500kPa, the microcapsules distributed in the deformation buffer layer will rupture at the critical point of the shell strength, releasing the phase change material and catalyst filled inside. The phase change material quickly penetrates into the surrounding stress transfer layer microstructure and undergoes a cross-linking reaction under the action of the catalyst. The generated new polymer forms a synergistic reinforcement effect with the surrounding materials, thereby further improving the strength and durability of the connection interface.

[0117] Actual performance tests show that this coating structure can significantly improve the connection performance of the module unit. Under the predetermined pressure, the adhesion strength of the coating increased by 30%, and after 1,000 loading cycles, the strength of the connection interface remained stable. In addition, the phase change reaction of the microcapsule can maintain stability under different temperature and humidity environments without premature rupture or functional failure.

[0118] By introducing the microcapsule structure into the multi-layer functional coating structure, not only the phase change characteristics under pressure are realized, but also the connection performance of the module unit is optimized through the adaptive reinforcement mechanism.

[0119] Although the present application is disclosed as above in the form of a preferred embodiment, it is not intended to limit the present application. Any technical personnel in this field may make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims of the present application.

Claims

1. A foldable and expandable modular prefabricated building product, characterized in that: The invention comprises a plurality of grouped building module units, wherein the grouped building module units comprises at least two building module units, and adjacent building module units are foldably connected by a flexible connecting belt, wherein the flexible connecting belt is made of a highly elastic resin substrate; The extended connection surface of each building module unit includes a multi-layer functional coating structure, and the multi-layer functional coating structure is used to realize the extended connection between the first group of building module units and the second group of building module units; the multi-layer functional coating structure includes a substrate bonding layer, a deformation buffer layer, a waterproof sealing layer and a stress transfer layer from the inside to the outside; Among them, the substrate bonding layer is used to achieve a firm bond between the functional coating and the building module unit; the deformation buffer layer is used to produce controllable deformation when the first group of building module units and the second group of building module units are subjected to external force, so as to avoid stress concentration and improve the adaptability of the connection interface; the waterproof sealing layer is used to form a dense waterproof structure through molecular chain rearrangement under the action of the prestress, so as to ensure the waterproof performance of the extended connection; the stress transfer layer is used to transfer and evenly distribute the prestress between the first group of building module units and the second group of building module units, so as to ensure the structural stability of the extended connection.

2. The foldable and expandable modular prefabricated building product according to claim 1, characterized in that: The high-elastic resin substrate of the flexible connecting belt includes a reinforcing fiber material, which is selected from one of aramid fiber, carbon fiber or glass fiber. The reinforcing fiber material is embedded along the longitudinal direction of the flexible connecting belt to form a multi-layer composite structure; the thickness of the flexible connecting belt ranges from 0.5 mm to 5 mm, and the content of the reinforcing fiber accounts for 5% to 25% of the total weight of the connecting belt; the surface of the flexible connecting belt is coated with a UV-resistant coating to improve the weather resistance under long-term exposure to sunlight.

3. The foldable and expandable modular prefabricated building product according to claim 1, characterized in that: The substrate bonding layer of the multi-layer functional coating structure includes nanoparticle filling materials to enhance the bonding force between the coating and the surface of the building module unit; the nanoparticles are selected from one or more of silicon oxide, titanium oxide or zinc oxide, and have an average particle size of 10 to 50 nanometers, and are distributed in the substrate bonding layer in a uniformly dispersed manner; the coating thickness of the substrate bonding layer is 50 to 200 microns, and is bonded to the surface of the building module unit substrate through plasma treatment or spraying technology, thereby ensuring that the adhesion performance of the functional coating is not affected under high humidity and high temperature difference conditions.

4. The foldable and expandable modular prefabricated building product according to claim 1, characterized in that: The deformation buffer layer includes a polymer-based material with shape memory function, and the polymer-based material is used to generate adaptive deformation when the ambient temperature changes, so as to further improve the connection adaptability between the module units; the thickness of the deformation buffer layer ranges from 0.1mm to 1mm, and its impact resistance and deformation recovery performance are further optimized by embedding micro-nano elastic particles or porous network structures.

5. The foldable and expandable modular prefabricated building product according to claim 1, characterized in that: The waterproof sealing layer adopts a multi-component interpenetrating network structure, which is formed by a cross-linking reaction of polyurethane, silicone rubber and acrylate materials; the multi-component interpenetrating network structure can quickly adjust the molecular arrangement when subjected to external pressure or stress through the dynamic rearrangement mechanism of the molecular chain, thereby realizing a dynamic self-repairing waterproof function; the thickness of the waterproof sealing layer ranges from 0.2 mm to 2 mm, and its surface has a nano-scale hydrophobic coating with a contact angle greater than 120 degrees, thereby improving the waterproof performance.

6. The foldable and expandable modular prefabricated building product according to claim 1, characterized in that: The stress transfer layer includes a stress-conducting microstructure, which is a regularly arranged hexagonal groove array, wherein the depth of the hexagonal groove is 50 to 200 microns and the width is 100 to 500 microns; the arrangement direction of the hexagonal groove array is consistent with the prestress transfer direction, so as to realize multi-dimensional stress transfer; the material of the stress transfer layer is an anisotropic polymer composite material, and the elastic modulus in the prestress transfer direction is 2 to 5 times that in the vertical direction.

7. The foldable and expandable modular prefabricated building product according to claim 1, characterized in that: The building module unit adopts a composite wall structure, including an outer high-strength frame and an inner lightweight filler; wherein the outer high-strength frame is made of carbon fiber reinforced epoxy resin, and the frame thickness is 30 to 50 mm; the inner lightweight filler is made of modified ceramsite concrete.

8. The foldable and expandable modular prefabricated building product according to claim 1, characterized in that: A stress sensing element is provided inside the flexible connecting belt. The stress sensing element is made of a graphene-doped conductive polymer, and its resistance value changes when the connecting belt is deformed. The stress sensing elements are evenly arranged along the length direction of the connecting belt with a spacing of 50 to 100 mm, and are used to monitor the stress distribution state during the folding process in real time.

9. The foldable and expandable modular prefabricated building product according to claim 1, characterized in that: A barrier coating is arranged between the deformation buffer layer and the waterproof sealing layer in the multi-layer functional coating structure. The thickness of the barrier coating is 10 to 50 microns. The barrier coating is made of a chemically resistant fluorocarbon polymer material.

10. The foldable and expandable modular prefabricated building product according to claim 1, characterized in that: The multi-layer functional coating structure has phase change characteristics under pressure, specifically including: a microcapsule structure is distributed in the deformation buffer layer, the shell layer of the microcapsule structure is made of polymethyl methacrylate, and the interior is filled with a temperature-sensitive phase change material and a pressure-responsive catalyst; when the extended connection surfaces of the two module units are in contact under a predetermined pressure, part of the microcapsules are ruptured, the phase change material and the catalyst are mixed and chemically reacted to generate a new polymer with a cross-linked network structure, and the new polymer penetrates into the microstructure of the stress transfer layer to form a synergistic enhancement effect.

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