A polylactic acid-aerogel crystal-based external wall construction method

Abstract

The application discloses a kind of based on polylactic acid-air condensing crystal heat insulation board outer wall construction method, belong to housing construction engineering technical field, including the following steps: to base wall is leveled and handled;Horizontal control line and vertical control line are set on the base wall;Preparation bonding mortar and troweling mortar;Install through length support bracket;Interface modification treatment is carried out to the sticking surface of polylactic acid-air condensing crystal heat insulation board, to form interface modification transition layer in the sticking surface;Alkali-resistant glass fiber mesh is pre-stuck in heat insulation layer terminal part;Bonding mortar is coated in the interface modification transition layer, the polylactic acid-air condensing crystal heat insulation board is stuck in the base wall;Anchor bolt is installed;Interface agent, two troweling mortars are sequentially constructed on polylactic acid-air condensing crystal heat insulation board outer surface, form anti-crack protective layer.The application has both heat insulation, fireproof effect, can improve interface bonding strength, improve anti-crack protective performance.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, specifically to an exterior wall construction method based on polylactic acid-aerocrystalline insulation board. Background Technology

[0002] In the field of building construction, exterior wall insulation materials are a crucial component of building energy conservation systems. Currently, commonly used exterior wall insulation materials mainly fall into two categories: organic and inorganic. Organic insulation materials, such as extruded polystyrene foam (XPS), polyurethane foam (PU), and phenolic foam (PF), are widely used due to their low density, low water absorption, and excellent thermal insulation performance, resulting in good building energy conservation. However, these materials generally suffer from poor adhesion, low fire resistance, and flammability, limiting their application in buildings with high fire safety requirements. Inorganic insulation materials, such as rock wool boards, while possessing good fire resistance, have relatively insufficient thermal insulation performance and a high thermal conductivity, making it difficult to simultaneously meet the dual requirements of thermal insulation and fire resistance.

[0003] Therefore, there is an urgent need to develop an external wall insulation system that combines excellent thermal insulation and fire resistance, along with corresponding construction methods, to resolve the technical contradiction of the difficulty in achieving both thermal insulation and fire resistance in existing technologies. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention provides an exterior wall construction method based on polylactic acid-aerocrystalline insulation boards. By modifying the interface of the insulation board's bonding surface to form a transition layer, the interfacial bonding strength between the board and the bonding mortar is significantly enhanced. Applying an interface agent and two coats of finishing mortar to the outer surface of the insulation board further improves the adhesion between the board and the finishing mortar, forming a continuous and uniform crack-resistant protective layer. Combined with complete construction steps including base treatment, layout of the boards, bracket installation, pre-application of the mesh fabric, and step-by-step installation of anchor bolts, a reliable and systematic exterior wall insulation construction solution is formed. This method solves the problems of difficulty in simultaneously achieving insulation and fireproofing, low bonding strength, and easy cracking of the protective layer in existing technologies, and has good prospects for widespread application. To achieve the above objectives, this invention is implemented through the following technical solutions: An exterior wall construction method based on polylactic acid-aerocrystalline insulation board includes the following steps: (1) Level the base wall; (2) Mark control lines on the base wall and determine the layout of the insulation boards; (3) Prepare bonding mortar and finishing mortar; (4) Install a support bracket for supporting the insulation board at a predetermined location on the base wall; (5) The bonding surface of the polylactic acid-aerocrystalline insulation board is subjected to interface modification treatment to form an interface modification transition layer on the bonding surface; the interface modification treatment includes: irradiating the bonding surface; applying an interface agent to the irradiated bonding surface, the wet film coating thickness of the interface agent being 0.1mm-0.5mm, so that the interface agent penetrates into the surface pores of the polylactic acid-aerocrystalline insulation board and cures to form the interface modification transition layer. (6) Pre-attach alkali-resistant fiberglass mesh for wrapping at the end of the insulation layer, with a portion of the alkali-resistant fiberglass mesh attached to the base wall and the other portion reserved outside the base wall; (7) Apply bonding mortar to the interface modified transition layer and attach the polylactic acid-aerocrystalline insulation board to the base wall; (8) Install anchor bolts to anchor the polylactic acid-aerocrystalline insulation board to the base wall; (9) Apply a crack-resistant protective layer to the outer surface of the polylactic acid-aerocrystalline insulation board: Apply one layer of interface agent and two layers of plastering mortar to the outer surface of the polylactic acid-aerocrystalline insulation board in sequence to form a crack-resistant protective layer; specifically, after the interface agent is surface dry, apply the first layer of plastering mortar, press in the alkali-resistant fiberglass mesh before the first layer of plastering mortar is cured, and then apply the second layer of plastering mortar so that the alkali-resistant fiberglass mesh is completely covered by the plastering mortar, wherein the wet film coating thickness of the interface agent is 0.05mm-0.2mm.

[0005] Furthermore, the irradiation treatment is performed using ultraviolet light with a wavelength of 185-254nm, an irradiation intensity of 10-30mW / cm², an irradiation time of 60-150s, and a distance of 30-60mm between the ultraviolet light source and the bonding surface; during the irradiation process, the surface temperature of the bonding surface is controlled to not exceed 60℃.

[0006] Furthermore, by weight, the interface agent comprises the following components: 45-70 parts of aqueous epoxy resin emulsion, 15-35 parts of nano-SiO2 sol, 2-10 parts of low molecular weight alcohol penetration enhancer, 0.5-4 parts of epoxy silane coupling agent, and 5-25 parts of deionized water.

[0007] The waterborne epoxy resin emulsion contains 50-65% waterborne epoxy resin by mass and has an epoxy equivalent of 400-1000 g / eq. The nano-SiO2 sol is an aqueous nano-SiO2 sol, wherein the mass content of SiO2 is 20-40%, the average particle size of the nano-SiO2 particles is 10-30 nm, and the pH value of the nano-SiO2 sol is 7-10. The low molecular weight alcohol penetration enhancer is selected from one or more of ethanol, isopropanol, n-propanol, and ethylene glycol; The epoxy silane coupling agent is selected from one or both of γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropyltriethoxysilane.

[0008] Among them, waterborne epoxy resin emulsion is used for film formation, bonding, and water resistance; nano-SiO2 fills the surface pores, improving hardness, roughness, and cohesive strength; low-molecular-weight alcohol reduces surface tension and promotes the wetting and penetration of the interface agent; epoxy-based silane coupling agent reduces the interfacial energy between the organic and inorganic phases, thereby improving compatibility. The components, in synergy with the active groups generated by ultraviolet irradiation, form a transition layer through penetration, chemical bonding, and nano-reinforcement, improving the bonding strength between the insulation board and the bonding mortar.

[0009] Furthermore, in step (7), the polylactic acid-aerocrystalline insulation board is bonded using a full-adhesion method. A notched trowel is used to apply bonding mortar to the interface-modified transition layer, and the polylactic acid-aerocrystalline insulation board is then bonded in place by pressing and sliding. Specifically: a square-toothed trowel is used to unidirectionally scrape the bonding mortar, forming a mortar layer with striped protrusions; the lower end of the polylactic acid-aerocrystalline insulation board is attached to the base wall, and it is evenly pressed from bottom to top and slid in place horizontally, so that the mortar layer is flattened and fills the interface gaps during the sliding process. The notched trowel has a tooth pitch of 8mm-12mm and a tooth depth of 6mm-10mm; the sliding displacement along the horizontal direction is 10mm-30mm; adjacent rows of polylactic acid-aerocrystalline insulation boards are staggered, and the polylactic acid-aerocrystalline insulation boards at the corners are interlocked.

[0010] Further, in step (8), the anchor bolts include a first part anchor bolt and a second part anchor bolt; after the bonding mortar has cured, the polylactic acid-aerocrystalline insulation board is anchored to the base wall through the first part anchor bolts; the second part anchor bolts are installed during the construction of the crack-resistant protective layer; specifically, after pressing in the alkali-resistant fiberglass mesh, the alkali-resistant fiberglass mesh reserved outside the base wall is flipped over the end face of the polylactic acid-aerocrystalline insulation board, and at the same time, alkali-resistant fiberglass mesh is laid on the outer surface of the polylactic acid-aerocrystalline insulation board, and the second part anchor bolts are installed at this time; the number of the first part anchor bolts is 45-55% of the total number of anchor bolts, and the number of the second part anchor bolts is the remaining part of the total number of anchor bolts.

[0011] Further, step (9) specifically includes: applying an interface agent to the outer surface of the polylactic acid-aerocrystalline insulation board, wherein the wet film coating thickness of the interface agent is 0.05mm-0.2mm; applying a first layer of plastering mortar after the interface agent has dried, and pressing in alkali-resistant fiberglass mesh before the first layer of plastering mortar has cured; and applying a second layer of plastering mortar on the alkali-resistant fiberglass mesh to form a crack-resistant protective layer.

[0012] Furthermore, the predetermined locations are the plinth at the bottom of the building and the reinforced concrete structural components of each floor. The support bracket is a continuous support bracket, with one bracket installed every two floors for the part of the building with a height of less than 40m, and one bracket installed on each floor for the part of the building with a height of more than 40m.

[0013] Furthermore, the terminal portion of the insulation layer is at least one of the following: door and window openings, parapet walls, structural expansion joints, system expansion joints, eaves, and plinths.

[0014] Compared with existing technologies, the advantages of this exterior wall construction method based on polylactic acid-aerocrystalline insulation board are: The polylactic acid-aerocrystalline insulation board used in this invention is made of polylactic acid foam particles and calcium magnesium sulfate double salt binder as the main raw materials. It has excellent properties such as low density, high strength, low thermal conductivity (≤0.040 W / (m·K)) and non-combustibility. It can simultaneously meet the requirements of building envelope for thermal insulation and fire safety, and overcome the technical defects of traditional organic insulation materials being flammable and inorganic insulation materials having high thermal conductivity.

[0015] This invention can improve the interfacial bonding strength. Before bonding the polylactic acid-aerocrystalline insulation board, the bonding surface of the polylactic acid-aerocrystalline insulation board is subjected to interfacial modification treatment to form an interfacial modification transition layer on the bonding surface. This can improve the wettability and bonding performance of the insulation board surface, enhance the interfacial bonding force between the insulation board and the bonding mortar, and reduce the risk of hollowing, cracking and falling off.

[0016] This invention can improve crack resistance and protection performance. After bonding the polylactic acid-aerocrystalline insulation board and installing anchor bolts, an interface agent and two coats of finishing mortar are applied to the outer surface of the insulation board. The interface agent can enhance the bonding effect between the insulation board and the finishing mortar, forming a continuous and uniform crack-resistant protective layer, reducing cracking of the protective layer and extending its service life. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0018] Figure 1 This is a flowchart of an exterior wall construction method based on polylactic acid-aerocrystalline insulation board according to the present invention.

[0019] Figure 2 This is a schematic diagram of an exterior wall structure based on polylactic acid-aerocrystalline insulation board according to the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] Example 1:

[0022] Please see Figure 1 , 2 An exterior wall construction method based on polylactic acid-aerocrystalline insulation board includes the following steps: (1) The base wall is leveled with mortar to make the base wall flat and free of any attachments that may affect the bonding. The base wall should be solid and flat, and the surface should be clean, free of oil stains, residual mortar blocks, dust, release agents, and other attachments that may affect adhesion.

[0023] (2) Based on the building facade design requirements, draw horizontal control lines and hang vertical control lines on the base wall to control the verticality and flatness of the insulation board bonding. And determine the layout of the polylactic acid-aerocrystalline insulation board according to the building facade design requirements and the site conditions.

[0024] (3) Prepare bonding mortar and finishing mortar; When using bonding mortar and finishing mortar, strictly follow the mixing ratio and preparation process provided by the material supplier. Add water directly to the dry powder and mix thoroughly with an electric mixer until the required viscosity for the project is achieved. Do not prepare too much at once, and use it within the time specified in the product instructions, depending on the ambient temperature.

[0025] (4) Install a continuous support bracket at the bottom of the building and at the reinforced concrete structural members of the floors to support the polylactic acid-aerocrystalline insulation board. For the part of the building with a height of less than 40m, a continuous support bracket shall be installed every two floors, and for the part with a height of more than 40m, a continuous support bracket shall be installed on each floor. The full-length support bracket is made of stainless steel, aluminum alloy, or metal with a hot-dip galvanized surface.

[0026] (5) The bonding surface of the polylactic acid-aerocrystalline insulation board is subjected to interface modification treatment to form an interface modification transition layer on the bonding surface. The polylactic acid-aerocrystalline insulation board used in this embodiment is a commercially available product manufactured by Anhui Beijia Green Building Materials Co., Ltd. The polylactic acid-aerocrystalline insulation board is made primarily from polylactic acid foam particles and calcium magnesium sulfate double salt binder; wherein, the polylactic acid foam particles are obtained from polylactic acid resin through a supercritical CO2 microporous foaming process, and the calcium magnesium sulfate double salt binder is prepared according to the method described in Chinese Invention Patent Application No. 201910270626.7. This application refers to inorganic cementing materials containing the calcium magnesium sulfate double salt binder as "aerocrystalline materials".

[0027] Polylactic acid (PLA) aerocrystalline insulation board material has the following performance indicators: thermal conductivity ≤0.040 W / (m・K), fire rating A, and density 80~100 kg / m³. 3 With a compressive strength ≥0.30 MPa and a volumetric water absorption rate ≤5%, this polylactic acid-aerocrystalline insulation board material boasts excellent properties such as low density, high strength, low thermal conductivity, and non-combustibility, making it suitable as a thermal insulation material for building envelopes.

[0028] The interface modification treatment includes: irradiating the bonding surface; applying an interface agent to the irradiated bonding surface, allowing the interface agent to penetrate into the surface pores of the polylactic acid-aerocrystalline insulation board and solidify to form the interface modification transition layer. Specifically, the bonding surface of the polylactic acid-aerocrystalline insulation board is irradiated with ultraviolet light. This irradiation treatment can be pre-completed after the polylactic acid-aerocrystalline insulation board is prepared. The wavelength of the ultraviolet light is 185-254 nm, and the irradiation intensity is 10-30 mW / cm². 2 The irradiation time is 60-150s, and the distance between the ultraviolet light source and the bonding surface is 30-60mm; the surface temperature of the bonding surface is controlled not to exceed 60℃ during the irradiation process.

[0029] The interface agent, by weight, comprises the following components: 45-70 parts of waterborne epoxy resin emulsion, 15-35 parts of nano-SiO2 sol, 2-10 parts of low molecular weight alcohol penetration enhancer, 0.5-4 parts of epoxy silane coupling agent, and 5-25 parts of deionized water.

[0030] The waterborne epoxy resin in the waterborne epoxy resin emulsion has a mass content of 50-65% and an epoxy equivalent of 400-1000 g / eq.

[0031] The nano-SiO2 sol is an aqueous nano-SiO2 sol, wherein the mass content of SiO2 is 20-40%, the average particle size of the nano-SiO2 particles is 10-30 nm, and the pH value of the nano-SiO2 sol is 7-10.

[0032] The low molecular weight alcohol penetration enhancer is selected from one or more of ethanol, isopropanol, n-propanol, and ethylene glycol.

[0033] The epoxy silane coupling agent is selected from one or both of γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropyltriethoxysilane.

[0034] The wet film thickness of the interface agent is 0.1mm-0.5mm; after applying the interface agent, it is dried to a surface dry state at room temperature before the bonding mortar is applied.

[0035] Among them, waterborne epoxy resin emulsion is used for film formation, bonding, and water resistance; nano-SiO2 fills the surface pores, improving hardness, roughness, and cohesive strength; low-molecular-weight alcohol reduces surface tension and promotes the wetting and penetration of the interface agent; epoxy-based silane coupling agent reduces the interfacial energy between the organic and inorganic phases, thereby improving compatibility. The components, in synergy with the active groups generated by ultraviolet irradiation, form a transition layer through penetration, chemical bonding, and nano-reinforcement, improving the bonding strength between the insulation board and the bonding mortar.

[0036] (6) At least one end of the insulation layer at door and window openings, parapet walls, structural expansion joints, system expansion joints, eaves, and plinths, alkali-resistant fiberglass mesh is pre-attached for wrapping. One end of the alkali-resistant fiberglass mesh is pre-attached and pressed into the bonding mortar on the base wall, with a bonding width of not less than 100mm. The other end is reserved as a wrapping section, the width of which is not less than the sum of the thickness of the polylactic acid-aerocrystalline insulation board and 100mm. After the polylactic acid-aerocrystalline insulation board is pasted, the wrapping section is folded along the end face of the insulation board, pasted on the surface of the insulation board, and subsequently pressed into the plaster layer on the outer surface of the insulation board, wherein the width folded to the outer surface of the insulation board is not less than 100mm; the overlap width between adjacent alkali-resistant fiberglass meshes is not less than 100mm.

[0037] The alkali-resistant fiberglass mesh has a unit area mass of not less than 160g / m². 2 Narrow-width alkali-resistant fiberglass mesh.

[0038] (7) Apply bonding mortar to the interface modification transition layer of the polylactic acid-aerocrystalline insulation board, and paste the polylactic acid-aerocrystalline insulation board to the base wall from bottom to top along the horizontal direction. The polylactic acid-aerocrystalline insulation boards in adjacent rows are staggered, and the polylactic acid-aerocrystalline insulation boards at the corners are interlocked. Before pasting polylactic acid-aerocrystalline insulation boards, first check whether the insulation boards are dry and whether the surface is flat and clean; damp, uneven, or contaminated insulation boards must not be used.

[0039] The polylactic acid-aerocrystalline insulation board should be laid horizontally from bottom to top, with a stagger of 1 / 2 board length between upper and lower rows, and a minimum stagger of 200mm in some areas; the polylactic acid-aerocrystalline insulation boards at the corners of the walls should be interlocked; the joints of the polylactic acid-aerocrystalline insulation boards at door and window openings should not be located at the four corners of the openings, and a whole piece of polylactic acid-aerocrystalline insulation board should be used to cut the board, with the joints of the polylactic acid-aerocrystalline insulation boards at least 200mm away from the corners of the openings.

[0040] The polylactic acid-aerocrystalline insulation board is bonded using a full-adhesion method. A notched trowel is used to apply bonding mortar to the interface-modified transition layer, and the board is then bonded in place by pressing and sliding. Specifically: a square-toothed trowel is used to unidirectionally scrape the bonding mortar, forming a mortar layer with raised stripes; the lower end of the polylactic acid-aerocrystalline insulation board is then attached to the base wall, and the board is evenly pressed from bottom to top and slid horizontally into place, flattening the mortar layer and filling the interface gaps during the sliding process. The notched trowel has a tooth pitch of 8mm-12mm and a tooth depth of 6mm-10mm; the horizontal sliding displacement is 10mm-30mm.

[0041] (8) Install anchor bolts using a step-by-step implantation method: At least 48 hours after the polylactic acid-aerocrystalline insulation board is pasted, i.e. after the bonding mortar has cured, the first set of anchor bolts is installed to anchor the polylactic acid-aerocrystalline insulation board to the base wall. Install the second set of anchor bolts during the construction of the crack-resistant protective layer; The number of anchors in the first part is 45-55% of the total number of anchors, and the number of anchors in the second part is the remaining part of the total number of anchors. Both the first part of anchors and the second part of anchors are arranged in a quincunx pattern.

[0042] When the building height is no more than 60m, the total number of the first and second part anchor bolts shall not be less than 8 per m. 2 When the building height is greater than 60m but not greater than 100m, the total number of anchor bolts in the first part and the second part shall not be less than 10 per meter. 2 .

[0043] The diameter of the plastic disc of the anchor bolt is not less than 50mm, and the depth of the anchor bolt installation hole is greater than the anchoring depth by 10mm. When the base wall is concrete, the effective anchoring depth of the anchor bolt in the concrete base is not less than 30mm. When the base is infill wall masonry, the effective anchoring depth of the anchor bolt in the infill wall masonry is not less than 50mm.

[0044] (9) Apply one layer of interface agent and two layers of finishing mortar sequentially to the outer surface of the polylactic acid-aerocrystalline insulation board to form a crack-resistant protective layer. Specifically, after the interface agent has dried to the touch, apply the first layer of finishing mortar. Before the first layer of finishing mortar has cured, press in the alkali-resistant fiberglass mesh. Then, fold the alkali-resistant fiberglass mesh reserved in step six over the end face of the polylactic acid-aerocrystalline insulation board. At the same time, lay the alkali-resistant fiberglass mesh on the outer surface of the polylactic acid-aerocrystalline insulation board. At this time, install the second part of the anchor bolts. Then apply the second layer of finishing mortar so that the alkali-resistant fiberglass mesh is completely covered by the finishing mortar. Finally, apply the finishing layer to the outer surface of the crack-resistant protective layer.

[0045] The interface agent used in step (9) is the same as that used in step five. The wet film coating thickness of this interface agent is 0.05mm-0.2mm. After applying the interface agent, it is dried to a surface dry state at room temperature before the finishing mortar is applied. The thickness of the crack-resistant protective layer is 4-6mm.

[0046] This invention uses polylactic acid-aerocrystalline insulation board to replace traditional insulation materials, and has the following technical effects: Combining thermal insulation and fireproofing effects: Polylactic acid-aerocrystalline insulation board material has excellent properties such as low density, high strength, low thermal conductivity, good thermal insulation performance, and non-combustibility, making it suitable as a thermal insulation material for building envelopes.

[0047] Improve interfacial bonding strength: Before bonding the polylactic acid-aerocrystalline insulation board, the bonding surface of the polylactic acid-aerocrystalline insulation board is subjected to interfacial modification treatment to form an interfacial modification transition layer on the bonding surface. This can improve the wettability and bonding performance of the insulation board surface, enhance the interfacial bonding force between the insulation board and the bonding mortar, and reduce the risk of hollowing, cracking and falling off.

[0048] Improve crack resistance and protection performance: After bonding the polylactic acid-aerocrystalline insulation board and installing the anchor bolts, apply one layer of interface agent and two layers of plastering mortar to the outer surface of the insulation board. The interface agent can enhance the bonding effect between the insulation board and the plastering mortar, forming a continuous and uniform crack-resistant protective layer, reducing cracking of the protective layer and extending its service life.

[0049] Example 2:

[0050] The bonding surface of the polylactic acid-aerocrystalline insulation board was irradiated with ultraviolet light at a wavelength of 254 nm, with an irradiation intensity of 10 mW / cm². 2 The irradiation time was 150 seconds, and the distance between the ultraviolet light source and the bonding surface was 60 mm. During the irradiation process, the surface temperature of the bonding surface was controlled to not exceed 45℃.

[0051] Preparation of the interface agent: Weigh the following raw materials by weight: self-crosslinking aqueous epoxy resin emulsion: 50 parts; aqueous nano-SiO2 sol: 20 parts; ethanol: 5 parts; γ-glycidoxypropyltrimethoxysilane: 1 part; deionized water: 24 parts. The self-crosslinking aqueous epoxy resin emulsion contains 50% aqueous epoxy resin by weight, with an epoxy equivalent of 1000 g / eq; the aqueous nano-SiO2 sol contains 20% SiO2 by weight, with an average particle size of 10 nm and a pH of 7.0. First, mix the aqueous epoxy resin emulsion and aqueous nano-SiO2 sol evenly, then add deionized water and ethanol, and finally add γ-glycidoxypropyltrimethoxysilane. Stir evenly to obtain the interface agent.

[0052] The interface agent is applied to the bonding surface after UV irradiation treatment, with a wet film thickness of 0.1 mm. It is then dried at room temperature (23±2℃, 50±5% relative humidity) for 30 minutes until the interface agent reaches a surface-dry state. Subsequently, the bonding mortar is applied, and the resulting bonding mortar layer has a thickness of 3 mm after curing.

[0053] Example 3:

[0054] The bonding surface of the polylactic acid-aerocrystalline insulation board was irradiated with ultraviolet light at a wavelength of 222 nm, with an irradiation intensity of 20 mW / cm². 2 The irradiation time was 100 seconds, and the distance between the ultraviolet light source and the bonding surface was 45 mm. During the irradiation process, the surface temperature of the bonding surface was controlled to not exceed 50℃.

[0055] Preparation of the interface agent: Weigh the following raw materials by weight: self-crosslinking waterborne epoxy resin emulsion: 60 parts; waterborne nano-SiO2 sol: 25 parts; isopropanol: 6 parts; γ-glycidoxypropyltriethoxysilane: 2 parts; deionized water: 7 parts. The self-crosslinking waterborne epoxy resin emulsion contains 58% waterborne epoxy resin by weight, with an epoxy equivalent of 700 g / eq; the waterborne nano-SiO2 sol contains 30% SiO2 by weight, with an average particle size of 20 nm and a pH of 8.5. First, mix the waterborne epoxy resin emulsion and the waterborne nano-SiO2 sol, stirring until homogeneous. Then, slowly add the pre-mixed isopropanol and deionized water, followed by the addition of γ-glycidoxypropyltriethoxysilane, and continue stirring until homogeneous to obtain the interface agent.

[0056] The interface agent is applied to the bonding surface after UV irradiation treatment, with a wet film thickness of 0.3 mm. It is then dried at room temperature (23±2℃, 50±5% relative humidity) for 45 minutes until the interface agent reaches a surface-dry state. Subsequently, the bonding mortar is applied, and the resulting bonding mortar layer has a thickness of 4 mm after curing.

[0057] Example 4: The bonding surface of the polylactic acid-aerocrystalline insulation board was irradiated with ultraviolet light of wavelength 185nm. The irradiation intensity at the bonding surface was 30mW / cm², the irradiation time was 60s, and the distance between the ultraviolet light source and the bonding surface was 30mm. During the irradiation process, the surface temperature of the bonding surface was controlled to not exceed 58℃ by air cooling.

[0058] Preparation of the interface agent: The following raw materials were weighed by weight: self-crosslinking waterborne epoxy resin emulsion: 55 parts; waterborne nano-SiO2 sol: 30 parts; a mixed penetration enhancer composed of n-propanol and ethylene glycol: 8 parts; a mixed coupling agent composed of γ-glycidyl etheroxypropyltrimethoxysilane and γ-glycidyl etheroxypropyltriethoxysilane: 2 parts; deionized water: 5 parts. The mass ratio of n-propanol to ethylene glycol was 3:1; the mass ratio of γ-glycidyl etheroxypropyltrimethoxysilane to γ-glycidyl etheroxypropyltriethoxysilane was 1:1. The self-crosslinking waterborne epoxy resin emulsion contained 65% waterborne epoxy resin and had an epoxy equivalent of 400 g / eq; the waterborne nano-SiO2 sol contained 40% SiO2, with an average particle size of 30 nm and a pH of 10.0. First, the aqueous epoxy resin emulsion and aqueous nano-SiO2 sol are mixed evenly; then, n-propanol, ethylene glycol and deionized water are premixed and slowly added; finally, two epoxy silane coupling agents are added, and the mixture is stirred until the system is homogeneous to obtain the interface agent.

[0059] The interface agent is applied to the bonding surface after UV irradiation treatment, with a wet film thickness of 0.5 mm. It is then dried at room temperature (23±2℃, 50±5% relative humidity) for 60 minutes until the interface agent reaches a surface-dry state. Subsequently, the bonding mortar is applied, and the resulting bonding mortar layer has a thickness of 5 mm after curing.

[0060] Comparative Example 1: Unlike Example 4, the interface modification transition layer was missing. Adhesive mortar was directly applied to the bonding surface of the polylactic acid-aerocrystalline insulation board, and the thickness of the adhesive mortar layer formed after curing was 5 mm.

[0061] The tensile bond strength and main failure modes of the polylactic acid-aerocrystalline insulation board and bonding mortar in Examples 2-4 and the comparative examples were tested. The results are shown in Table 1.

[0062] Experimental group Tensile bond strength / MPa Forms of destruction Testing standards JG / T 287-2013 Apparent Example 2 0.191±0.011 The main cause of the surface cohesive failure of the insulation board Example 3 0.221±0.012 Cohesion failure of insulation board Example 4 0.201±0.013 The insulation board mainly suffers from surface cohesive failure, with localized interfacial layer cohesive failure. Comparative Example 1 0.087±0.009 The main issue is the debonding at the interface between the insulation board and the mortar. Note: Tensile bond strength was tested according to the relevant test methods in JG / T 287-2013. Six parallel specimens were set up for each group. The test results in the table are expressed as "mean value ± standard deviation"; the main failure mode was determined by observing the failure surface of the specimen.

[0063] As shown in Table 1, the tensile bond strength of Examples 2-4 was significantly improved compared to Comparative Example 1. Furthermore, Examples 2-4 mainly experienced cohesive failure of the insulation board or cohesive failure of the surface layer of the insulation board, while Comparative Example 1 mainly experienced interfacial debonding between the insulation board and the bonding mortar. This indicates that under the experimental conditions, the interface-modified transition layer formed by ultraviolet irradiation and interface agent treatment improved the interfacial bonding performance between the insulation board and the bonding mortar, making this interface no longer the main weak point of the specimen and improving the tensile bond strength between them.

[0064] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing exterior walls based on polylactic acid-aerocrystalline insulation boards, characterized in that, Includes the following steps: (1) Level the base wall; (2) Mark control lines on the base wall and determine the layout of the insulation boards; (3) Prepare bonding mortar and finishing mortar; (4) Install a support bracket for supporting the insulation board at a predetermined location on the base wall; (5) The bonding surface of the polylactic acid-aerocrystalline insulation board is subjected to interface modification treatment to form an interface modification transition layer on the bonding surface. (6) Pre-attach alkali-resistant fiberglass mesh for wrapping at the end of the insulation layer; (7) Apply bonding mortar to the interface modified transition layer and attach the polylactic acid-aerocrystalline insulation board to the base wall; (8) Install anchor bolts to anchor the polylactic acid-aerocrystalline insulation board to the base wall; (9) Apply a crack-resistant protective layer to the outer surface of the polylactic acid-aerocrystalline insulation board.

2. The method for constructing exterior walls based on polylactic acid-aerocrystalline insulation boards according to claim 1, characterized in that, The interface modification treatment includes: irradiating the bonding surface; applying an interface agent to the irradiated bonding surface, allowing the interface agent to penetrate into the surface pores of the polylactic acid-aerocrystalline insulation board and solidify, thereby forming the interface modification transition layer.

3. The exterior wall construction method based on polylactic acid-aerocrystalline insulation board according to claim 2, characterized in that, The irradiation treatment is performed using ultraviolet light with a wavelength of 185-254nm, an irradiation intensity of 10-30mW / cm², an irradiation time of 60-150s, and a distance of 30-60mm between the ultraviolet light source and the bonding surface. During the irradiation process, the surface temperature of the bonding surface is controlled to not exceed 60℃, and the wet film coating thickness of the interface agent is 0.1mm-0.5mm.

4. The exterior wall construction method based on polylactic acid-aerocrystalline insulation board according to claim 2, characterized in that, The interface agent, by weight, comprises the following components: 45-70 parts of aqueous epoxy resin emulsion, 15-35 parts of nano-SiO2 sol, 2-10 parts of low molecular weight alcohol penetration enhancer, 0.5-4 parts of epoxy silane coupling agent, and 5-25 parts of deionized water.

5. The exterior wall construction method based on polylactic acid-aerocrystalline insulation board according to claim 1, characterized in that, Step (7) specifically includes: A toothed scraper is used to apply bonding mortar to the interface modified transition layer to form a mortar layer with striped protrusions. The lower end of the polylactic acid-aerocrystalline insulation board is attached to the base wall, and is evenly pressed from bottom to top and slid into place in the horizontal direction. The polylactic acid-aerocrystalline insulation boards in adjacent rows are staggered, and the polylactic acid-aerocrystalline insulation boards at the corners are interlocked.

6. The method for constructing exterior walls based on polylactic acid-aerocrystalline insulation boards according to claim 1, characterized in that, Step (8) specifically includes: After the bonding mortar has cured, install the first part of the anchor bolts; Install the second set of anchor bolts during the construction of the crack-resistant protective layer; The first part consists of 45-55% of the total number of anchors, and the second part consists of the remaining portion of the total number of anchors.

7. The method for constructing exterior walls based on polylactic acid-aerocrystalline insulation boards according to claim 2, characterized in that, Step (9) specifically includes: An interface agent is applied to the outer surface of the polylactic acid-aerocrystalline insulation board, and the wet film coating thickness of the interface agent is 0.05mm-0.2mm. After the interface agent has dried to the surface, apply the first coat of plastering mortar and press in alkali-resistant fiberglass mesh before the first coat of plastering mortar has cured. Apply a second layer of plastering mortar to the alkali-resistant fiberglass mesh to form a crack-resistant protective layer.

8. The method for constructing exterior walls based on polylactic acid-aerocrystalline insulation boards according to claim 4, characterized in that, The waterborne epoxy resin emulsion contains 50-65% waterborne epoxy resin by mass and has an epoxy equivalent of 400-1000 g / eq. The nano-SiO2 sol is an aqueous nano-SiO2 sol, wherein the mass content of SiO2 is 20-40%, the average particle size of the nano-SiO2 particles is 10-30 nm, and the pH value of the nano-SiO2 sol is 7-10. The low molecular weight alcohol penetration enhancer is selected from one or more of ethanol, isopropanol, n-propanol, and ethylene glycol; The epoxy silane coupling agent is selected from one or both of γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropyltriethoxysilane.

9. The method for constructing exterior walls based on polylactic acid-aerocrystalline insulation boards according to claim 1, characterized in that, The predetermined locations are the plinth at the bottom of the building and the reinforced concrete structural components of each floor. The support bracket is a continuous support bracket, with one bracket installed every two floors for the part of the building with a height of less than 40m, and one bracket installed on each floor for the part of the building with a height of more than 40m.

10. The method for constructing exterior walls based on polylactic acid-aerocrystalline insulation boards according to claim 1, characterized in that, The end point of the insulation layer is at least one of the following: door and window openings, parapet walls, structural expansion joints, system expansion joints, eaves, and plinths.

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