Preparation method of vitrified microcapsule thermal insulation mortar based on phase change microcapsules

Abstract

This application relates to the field of building insulation materials technology, specifically disclosing a method for preparing vitrified microcapsule insulation mortar based on phase change microcapsules. The method includes the following steps: dry mixing ZrO2 / ZnO / PDA multi-shell phase change microcapsules, phenolic resin foam-vitrified microsphere composite material, cement, cellulose ether, fly ash, polypropylene fiber, water-reducing agent, and redispersible latex powder for 25-30 seconds to obtain a preliminary mixture; adding water to the preliminary mixture and stirring for 60-90 seconds until homogeneous to obtain the vitrified microcapsule insulation mortar based on phase change microcapsules. The insulation mortar provided by this application exhibits excellent insulation performance and temperature regulation and energy storage capacity.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of building thermal insulation materials, and more particularly to a preparation method of vitrified microcapsule thermal insulation mortar based on phase change microcapsules. BACKGROUND

[0002] Improving the thermal insulation performance of walls helps to save energy, and residential building external wall thermal insulation is often achieved by attaching inorganic or organic thermal insulation materials to the wall. Organic thermal insulation materials are not resistant to aging, have poor stability, have a large deformation coefficient, and are easily flammable, so it is necessary to vigorously develop inorganic thermal insulation materials that are flame-retardant, durable, and can actively reduce building energy consumption. At present, vitrified microsphere thermal insulation mortar, as a common inorganic thermal insulation material for interior and exterior walls, has been widely used in the construction industry. However, traditional vitrified microsphere thermal insulation mortar has the problems of high thermal conductivity and limited thermal insulation effect.

[0003] Phase change materials can absorb or release a large amount of latent heat within the phase change temperature range, achieving energy storage and release. The combination of phase change materials and thermal insulation mortar can endow the mortar with temperature regulation and energy storage functions, effectively alleviating indoor temperature fluctuations. However, direct addition of phase change materials can cause leakage, agglomeration, and poor compatibility with the mortar matrix, affecting the mechanical properties and use stability of the mortar. Therefore, it is urgent to prepare a vitrified microcapsule thermal insulation mortar based on phase change microcapsules. SUMMARY

[0004] In order to solve the problems in the prior art, the application provides a preparation method of vitrified microcapsule thermal insulation mortar based on phase change microcapsules.

[0005] In a first aspect, the application provides a preparation method of vitrified microcapsule thermal insulation mortar based on phase change microcapsules, which adopts the following technical scheme: The preparation method of vitrified microcapsule thermal insulation mortar based on phase change microcapsules comprises the following steps: The ZrO2 / ZnO / PDA multi-shell phase change microcapsules, phenolic resin foam-vitrified microsphere composite material, cement, cellulose ether, fly ash, polypropylene fiber, water reducing agent and redispersible latex powder are dry mixed for 25-30s to obtain a preliminary mixture; Water is added to the preliminary mixture, and stirring is performed for 60-90s to obtain the vitrified microcapsule thermal insulation mortar based on phase change microcapsules.

[0006] By adopting the above technical scheme, the synergistic design of the high-performance composite shell phase change microcapsule and the phenolic resin foam-vitrified microsphere composite aggregate, combined with the modification and optimization of the cement-based gelling system, realizes the thermal insulation and temperature regulation performance. The phenolic resin foam itself is a super-lightweight thermal insulation material. After being combined with the vitrified microsphere, a lightweight aggregate with a multi-level pore structure is formed. Compared with single vitrified microsphere aggregate, the thermal conductivity of the aggregate layer is further reduced. In combination with the heat storage and temperature regulation effect of the ZrO2 / ZnO / PDA multi-shell phase change microcapsule, the overall thermal conductivity of the mortar is reduced, and the thermal insulation performance is further improved.

[0007] Optionally, the preparation method of the ZrO2 / ZnO / PDA multi-shell phase change microcapsule comprises the following steps: (1) After mixing and stirring the core material and formamide at 50 DEG C, CTAB is added and stirred until dissolved, emulsified for 10-15 min, the pH of the system is adjusted to 3-4, zirconium oxychloride is added, the pH of the system is adjusted to 8-9, and the system is incubated and placed for 36-40 h, then filtered, washed and dried to obtain ZrO2 coated microcapsules. The mass ratio of the core material, formamide, CTAB and zirconium oxychloride is 1-1.2:10-15:0.01-0.03:1.2-1.5; (2) The ZrO2 coated microcapsules are dispersed in an ethanol solution and ultrasonically treated to obtain a suspension. Zinc acetate is added to the suspension and stirred until dissolved. The pH of the system is adjusted to 9-10. The system is filtered, washed and dried to obtain ZrO2 / ZnO composite shell microcapsules. The mass ratio of the ZrO2 coated microcapsules, the ethanol solution and the zinc acetate is 1-1.5:20-30:0.6-0.8; (3) The ZrO2 / ZnO composite shell microcapsules and dopamine hydrochloride are added to water, ultrasonically treated, and the pH of the system is adjusted to 8-9. Under nitrogen protection, the system is stirred at 23-27 DEG C for 20-24 h. The system is filtered, washed and dried to obtain ZrO2 / ZnO / PDA multi-shell phase change microcapsules. The mass ratio of the ZrO2 / ZnO composite shell microcapsules and dopamine hydrochloride is 10-15:1-3.

[0008] By adopting the above technical solution, the ZrO2 bottom layer forms a uniform and dense inorganic shell layer through stepwise pH control, which can effectively encapsulate the core material and prevent core material leakage during phase change. The ZnO intermediate layer is deposited on the ZrO2 surface and is tightly bonded to the bottom layer. The subsequent PDA layer forms hydrogen bonds with the ZnO surface through catechol groups, further reinforcing the shell structure and improving the mechanical strength and cycle durability of the microcapsules. The ZnO layer has visible light absorption characteristics, which can broaden the spectral response range of the microcapsules and make fuller use of solar energy compared to a single ZrO2 shell layer. The PDA outer layer not only enhances visible light absorption, but also directly increases the local temperature through photothermal effect, forming a synergistic effect with ZnO and significantly improving the conversion efficiency of solar energy to thermal energy. The phase change enthalpy loss of the core material is small, and the coating of multiple inorganic shell layers does not destroy its solid-liquid phase change characteristics, and it can still maintain a high latent heat storage capacity.

[0009] Optionally, the core material is one or more of n-octadecane, n-eicosane, and n-docosahexadecane.

[0010] Optionally, the average particle size of the ZrO2 / ZnO / PDA multi-shell phase change microcapsules is 10-35 μm.

[0011] By adopting the above technical solution, this particle size range not only matches the microstructure of the mortar matrix and the aggregate particle size, but also maximizes the heat storage and temperature regulation function of the phase change microcapsules.

[0012] Optionally, the preparation method of the phenolic resin foam-vitrified microsphere composite material includes the following steps: (1) After mixing and stirring the phenolic resin, polyethylene glycol and foaming agent, p-toluenesulfonic acid is added and stirring is continued. Then, n-pentane is added dropwise to form a foaming precursor. The mass ratio of the phenolic resin, polyethylene glycol, foaming agent, p-toluenesulfonic acid and n-pentane is 100-110:5-8:3-5:4-6:2-4. (2) Add vitrified microspheres to the foaming precursor, stir for 10-15 min to obtain a mixture, keep warm for 30-40 min for initial curing, raise the temperature to 100-110℃, and cure for 2-3 h to obtain phenolic resin foam-vitrified microsphere composite material. The mass ratio of the foaming precursor to the pretreated vitrified microspheres is 6-8:1.

[0013] By adopting the above technical solution, phenolic resin itself is a natural flame-retardant material. When combined with non-combustible inorganic vitrified microspheres, a dual flame-retardant system is formed, which combines the flame retardancy of the organic matrix with the physical barrier of the inorganic filler, thereby improving the oxygen index of the composite material. The closed-cell structure of the phenolic resin foam and the hollow thermal insulation properties of the vitrified microspheres work synergistically, resulting in a lower thermal conductivity compared to the vitrified microspheres, improved insulation effect, and outstanding high-temperature resistance.

[0014] Optionally, the vitrified microspheres undergo the following pretreatment: The vitrified microspheres were sieved, washed, dried, and then added to the hydrolyzed silane coupling agent solution. The mixture was then ultrasonically treated, filtered, and dried.

[0015] By adopting the above technical solution, after modification with silane coupling agent, vitrified microspheres can form a cross-linked structure with cement hydration products, eliminate interfacial micro-gaps, and enhance interfacial adhesion.

[0016] Optionally, the foaming agent is one or more of n-pentane, cyclopentane, water, and methylpentane.

[0017] By adopting the above technical solution, the foaming agent forms a uniform and closed porous structure in the system through physical foaming, which ultimately endows the composite material with the core characteristics of being lightweight, having low thermal conductivity, and having high structural stability, thus meeting the application requirements of thermal insulation mortar aggregate.

[0018] Optionally, the cellulose ether is one or more of hydroxypropyl methylcellulose ether, hydroxyethyl cellulose ether, and methylcellulose ether.

[0019] In summary, this application has the following beneficial effects: 1. In this application, ZrO2 / ZnO / PDA multi-shell phase change microcapsules are preferred to be combined with phenolic resin foam-vitrified microspheres to achieve multi-level insulation and ultra-low thermal conductivity. The phenolic resin foam-vitrified microspheres themselves have a highly closed-cell, lightweight, porous structure, which forms an insulation skeleton with the cement-based cementitious system. The phase change microcapsules are uniformly filled in the gaps between aggregates and the micropores of cement hydration products to form a heat storage and temperature regulation layer. The two work together to reduce the overall thermal conductivity of the mortar and improve the insulation performance.

[0020] 2. In this application, a three-step preparation process of ZrO2 in-situ coating, ZnO secondary coating, and PDA surface modification was used to prepare ZrO2 / ZnO / PDA multi-shell phase change microcapsules. Through stepwise coating and layer-by-layer functionalization design, each shell material can accurately exert its own performance advantages, and a dense composite structure with chemical bonds is formed between the layers, which ultimately improves the heat storage efficiency of the phase change microcapsules.

[0021] 3. In this application, a composite material is prepared by using phenolic resin foam and vitrified microspheres. The composite material has a uniform pore structure. The heat insulation of the air inside the pores and the heat insulation effect of phenolic resin and vitrified microspheres form a three-level heat insulation synergistic effect, which significantly improves the heat insulation performance of the material. Detailed Implementation

[0022] The following embodiments provide a further detailed description of this application.

[0023] Example of preparation of ZrO2 / ZnO / PDA multi-shell phase change microcapsules Source of raw materials: The core material is n-octadecane.

[0024] Preparation Example 1-1: (1) Mix 1.2g core material and 15g formamide at 50℃ and stir for 40min until the system is uniform. Add 0.03g CTAB and stir until dissolved. Emulsify for 15min to obtain oil-solvent emulsion. Add 100mL 0.5mol / L nitric acid solution and stir for 10min. Adjust the pH of the system to 4. Add 1.5g zirconium oxychloride and stir at 1000r / min until completely dissolved. Add ammonia water and adjust the pH of the system to 9. Keep at 50℃ and stand for 40h. After the reaction is completed, filter, wash three times with deionized water, and dry at 25℃ for 6h to obtain ZrO2 coated microcapsules. (2) 1.5g of ZrO2-coated microcapsules were added to 30g of ethanol solution and ultrasonically dispersed at 300W for 30min to obtain a suspension. 0.8g of zinc acetate was added to the suspension and stirred until completely dissolved. Ammonia water was added to adjust the pH of the system to 10. The system was stirred continuously at 1000r / min for 8h. The mixture was filtered, washed three times with deionized water, and dried at 25℃ for 6h to obtain ZrO2 / ZnO composite shell microcapsules. (3) Add 15g of ZrO2 / ZnO composite shell microcapsules and 3g of dopamine hydrochloride to deionized water, ultrasonically disperse at 300W for 10min, adjust the pH to 9 with ammonia, stir continuously at 27℃ for 24h under nitrogen protection, filter, wash three times with deionized water, and dry at 25℃ for 6h to obtain ZrO2 / ZnO / PDA multi-shell phase change microcapsules.

[0025] Preparation Example 1-2: (1) 1.1g core material and 13g formamide were mixed and stirred at 50℃ for 35min until the system was uniform. 0.02g CTAB was added and stirred until dissolved. Emulsification was carried out for 13min to obtain an oil-solvent emulsion. 100mL of 0.5mol / L nitric acid solution was added and stirred for 10min. The pH of the system was adjusted to 3.5. 1.3g zirconium oxychloride was added and stirred at 1000r / min until completely dissolved. Ammonia water was added and the pH of the system was adjusted to 8.5. The system was kept at 50℃ for 38h. After the reaction was completed, the system was filtered, washed three times with deionized water, and dried at 25℃ for 6h to obtain ZrO2-coated microcapsules. (2) 1.2g of ZrO2-coated microcapsules were added to 25g of ethanol solution and ultrasonically dispersed at 300W for 30min to obtain a suspension. 0.7g of zinc acetate was added to the suspension and stirred until completely dissolved. Ammonia water was added to adjust the pH of the system to 9.5. The system was stirred continuously at 1000r / min for 8h. The mixture was filtered, washed three times with deionized water, and dried at 25℃ for 6h to obtain ZrO2 / ZnO composite shell microcapsules. (3) Add 12g of ZrO2 / ZnO composite shell microcapsules and 2g of dopamine hydrochloride to deionized water, disperse by ultrasonication at 300W for 10min, adjust the pH to 8.5 with ammonia, stir continuously at 25℃ for 22h under nitrogen protection, filter, wash three times with deionized water, and dry at 25℃ for 6h to obtain ZrO2 / ZnO / PDA multi-shell phase change microcapsules.

[0026] Preparation Examples 1-3: (1) Mix 1g of core material and 10g of formamide at 50°C for 30min until the system is uniform, add 0.01g of CTAB and stir until dissolved, emulsify for 10min to obtain an oil-solvent emulsion, add 100mL of 0.5mol / L nitric acid solution, stir for 10min, adjust the pH of the system to 3, add 1.2g of zirconium oxychloride, stir at 1000r / min until completely dissolved, add ammonia water, adjust the pH of the system to 8, keep at 50°C and stand for 36h, after the reaction is completed, filter, wash three times with deionized water, dry at 25°C for 6h to obtain ZrO2 coated microcapsules; (2) 1g of ZrO2-coated microcapsules were added to 20g of ethanol solution and ultrasonically dispersed at 300W for 30min to obtain a suspension. 0.6g of zinc acetate was added to the suspension and stirred until completely dissolved. Ammonia water was added to adjust the pH of the system to 9. The system was stirred continuously at 1000r / min for 8h. The mixture was filtered, washed three times with deionized water, and dried at 25℃ for 6h to obtain ZrO2 / ZnO composite shell microcapsules. (3) Add 10g of ZrO2 / ZnO composite shell microcapsules and 1g of dopamine hydrochloride to deionized water, ultrasonically disperse at 300W for 10min, adjust the pH to 8 with ammonia, stir continuously at 23℃ for 20h under nitrogen protection, filter, wash three times with deionized water, and dry at 25℃ for 6h to obtain ZrO2 / ZnO / PDA multi-shell phase change microcapsules.

[0027] Preparation Example 1-4: The difference from Preparation Example 1-1 is that ZrO2-coated microcapsules are used to replace ZrO2 / ZnO / PDA multi-shell phase change microcapsules in equal amounts. The preparation method of ZrO2-coated microcapsules is as follows: (1) 1.2g core material and 15g formamide are mixed and stirred at 50℃ for 40min until the system is uniform. 0.03g CTAB is added and stirred until dissolved. Emulsification is carried out for 15min to obtain an oil-solvent emulsion. 100mL of 0.5mol / L nitric acid solution is added and stirred for 10min. The pH of the system is adjusted to 4. 1.5g zirconium oxychloride is added and stirred at 1000r / min until completely dissolved. Ammonia water is added and the pH of the system is adjusted to 9. The system is kept at 50℃ for 40h. After the reaction is completed, the system is filtered, washed three times with deionized water, and dried at 25℃ for 6h to obtain ZrO2-coated microcapsules.

[0028] Preparation Example 1-5: The difference from Preparation Example 1-1 is that ZrO2 / ZnO composite shell microcapsules are used to replace ZrO2 / ZnO / PDA multi-shell phase change microcapsules in equal amounts. (1) 1.2g core material and 15g formamide are mixed and stirred at 50°C for 40min until the system is uniform. 0.03g CTAB is added and stirred until dissolved. Emulsification is carried out for 15min to obtain an oil-solvent emulsion. 100mL of 0.5mol / L nitric acid solution is added and stirred for 10min. The pH of the system is adjusted to 4. 1.5g zirconium oxychloride is added and stirred at 1000r / min until completely dissolved. Ammonia is added and the pH of the system is adjusted to 9. The system is kept at 50°C for 40h. After the reaction is completed, the system is filtered, washed three times with deionized water, and dried at 25°C for 6h to obtain ZrO2-coated microcapsules. (2) 1.5g of ZrO2-coated microcapsules were added to 30g of ethanol solution and ultrasonically dispersed at 300W for 30min to obtain a suspension. 0.8g of zinc acetate was added to the suspension and stirred until completely dissolved. Ammonia water was added to adjust the pH of the system to 10. The system was stirred continuously at 1000r / min for 8h. The mixture was filtered, washed three times with deionized water, and dried at 25℃ for 6h to obtain ZrO2 / ZnO composite shell microcapsules. Preparation example of phenolic resin foam-vitrified microsphere composite material

[0029] The raw materials are sourced from: phenolic resin from Shenzhen Yoshida Chemical Co., Ltd., with a solid content of 99%; p-toluenesulfonic acid from Shandong Jinruida New Material Co., Ltd., CAS number 104-15-4; and cyclopentane as the foaming agent.

[0030] Preparation Example 2-1: (1) Mix 110g of phenolic resin, 8g of polyethylene glycol and 5g of foaming agent and stir for 15min. Add 6g of p-toluenesulfonic acid and continue stirring for 8min. Add 4g of n-pentane dropwise and stir at 800r / min for 10min to form a foaming precursor. (2) Add 1g of vitrified microspheres to 8g of foaming precursor, stir at 500r / min for 15min to obtain a mixture, keep warm at 70℃ for 40min for initial curing, raise the temperature to 110℃, continue to keep warm, and cure for 3h for a second time to obtain phenolic resin foam-vitrified microsphere composite material.

[0031] Preparation Example 2-2: (1) Mix 105g of phenolic resin, 6g of polyethylene glycol and 4g of foaming agent and stir for 12min. Add 5g of p-toluenesulfonic acid and continue stirring for 7min. Add 3g of n-pentane dropwise and stir at 800r / min for 9min to form a foaming precursor. (2) Add 1g of vitrified microspheres to 7g of foaming precursor, stir at 500r / min for 12min to obtain a mixture, keep warm at 70℃ for 35min for initial curing, raise the temperature to 105℃, continue to keep warm, and cure for 2.5h for a second time to obtain phenolic resin foam-vitrified microsphere composite material.

[0032] Preparation Example 2-3: (1) Mix 100g of phenolic resin, 5g of polyethylene glycol and 3g of foaming agent and stir for 10min. Add 4g of p-toluenesulfonic acid and continue stirring for 5min. Add 2g of n-pentane dropwise and stir at 800r / min for 8min to form a foaming precursor. (2) Add 1g of vitrified microspheres to 6g of foaming precursor, stir at 500r / min for 10min to obtain a mixture, keep warm at 70℃ for 30min for initial curing, raise the temperature to 100℃, continue to keep warm, and cure for 2h for a second time to obtain phenolic resin foam-vitrified microsphere composite material.

[0033] Preparation Example 2-4: The difference from Preparation Example 2-1 is that the vitrified microspheres underwent the following pretreatment: the vitrified microspheres were passed through a 120-mesh standard sieve, washed three times with deionized water, dried at 60°C, added to the hydrolyzed silane coupling agent solution, ultrasonically dispersed at 300W for 15 minutes, filtered, washed three times with deionized water, dried at 60°C, 0.02g of silane coupling agent was added to a mixture of 10g of deionized water / ethanol (volume ratio of 3:7), the pH was adjusted to 5 with hydrochloric acid, and the mixture was stirred and hydrolyzed for 30 minutes to obtain the hydrolyzed silane coupling agent solution. SiO2 was added to 100g of ethanol solution, ultrasonically dispersed at 250W for 20 minutes, and then slowly added dropwise to the hydrolyzed silane coupling agent solution. Example

[0034] The raw materials are sourced as follows: cement from Henan Hongcheng New Material Technology Co., Ltd., specification HC-GSY; cellulose ether is hydroxypropyl methylcellulose ether, from Langfang Tianya Energy Saving Technology Co., Ltd., item number 7654; fly ash is from Lingshou County Shuntian Mineral Products Processing Plant, item number 6666; polypropylene fiber is from Willis Shandong New Material Technology Co., Ltd., specification 6mm; water-reducing agent is polycarboxylate water-reducing agent, from Henan Xijian New Building Materials Co., Ltd., product name polycarboxylate powder water-reducing agent; redispersible latex powder is from Zhengzhou Tengxiang Chemical Products Co., Ltd., item number 20251227.

[0035] Example 1: The preparation method of the vitrified microcapsule thermal insulation mortar based on phase change microcapsules includes the following steps: 12 kg of ZrO2 / ZnO / PDA composite shell phase change microcapsules, 30 kg of phenolic resin foam-vitrified microsphere composite material, 35 kg of cement, 0.6 kg of cellulose ether, 15 kg of fly ash, 0.3 kg of polypropylene fiber, 0.8 kg of water-reducing agent and 4 kg of redispersible latex powder were dry-mixed at 500 r / min for 30 s to obtain a preliminary mixture. Add 25 kg of deionized water to the preliminary mixture, stir at 600 r / min for 90 s, and mix evenly to obtain vitrified microcapsule thermal insulation mortar based on phase change microcapsules.

[0036] Example 2: The preparation method of the vitrified microcapsule thermal insulation mortar based on phase change microcapsules includes the following steps: 10 kg of ZrO2 / ZnO / PDA composite shell phase change microcapsules, 28 kg of phenolic resin foam-vitrified microsphere composite material, 33 kg of cement, 0.5 kg of cellulose ether, 14 kg of fly ash, 0.25 kg of polypropylene fiber, 0.7 kg of water-reducing agent and 3.5 kg of redispersible latex powder were dry-mixed at 500 r / min for 30 s to obtain a preliminary mixture. Add 23 kg of deionized water to the preliminary mixture, stir at 600 r / min for 90 s, and mix evenly to obtain vitrified microcapsule thermal insulation mortar based on phase change microcapsules.

[0037] Example 3: The preparation method of the vitrified microcapsule thermal insulation mortar based on phase change microcapsules includes the following steps: 9 kg of ZrO2 / ZnO / PDA composite shell phase change microcapsules, 26 kg of phenolic resin foam-vitrified microsphere composite material, 32 kg of cement, 0.4 kg of cellulose ether, 11 kg of fly ash, 0.2 kg of polypropylene fiber, 0.6 kg of water-reducing agent, and 3 kg of redispersible latex powder were dry-mixed at 500 r / min for 30 s to obtain a preliminary mixture. Add 22 kg of deionized water to the preliminary mixture, stir at 600 r / min for 90 s, and mix evenly to obtain vitrified microcapsule thermal insulation mortar based on phase change microcapsules.

[0038] Example 4: The preparation method of the vitrified microcapsule thermal insulation mortar based on phase change microcapsules includes the following steps: 8 kg of ZrO2 / ZnO / PDA composite shell phase change microcapsules, 25 kg of phenolic resin foam-vitrified microsphere composite material, 30 kg of cement, 0.3 kg of cellulose ether, 10 kg of fly ash, 0.1 kg of polypropylene fiber, 0.5 kg of water-reducing agent, and 2 kg of redispersible latex powder were dry-mixed at 500 r / min for 30 s to obtain a preliminary mixture. Add 20 kg of deionized water to the preliminary mixture, stir at 600 r / min for 90 s, and mix evenly to obtain vitrified microcapsule thermal insulation mortar based on phase change microcapsules.

[0039] Example 5: The preparation method of the vitrified microcapsule thermal insulation mortar based on phase change microcapsules differs from that of Example 1 in that ZrO2-coated microcapsules are used to replace the ZrO2 / ZnO / PDA multi-shell phase change microcapsules in equal amounts. The preparation method of ZrO2-coated microcapsules is as follows: (1) Mix 1.2g of core material and 15g of formamide at 50°C for 40min until the system is uniform. Add 0.03g of CTAB and stir until dissolved. Emulsify for 15min to obtain an oil-solvent emulsion. Add 100mL of 0.5mol / L nitric acid solution and stir for 10min. Adjust the pH of the system to 4. Add 1.5g of zirconium oxychloride and stir at 1000r / min until completely dissolved. Add ammonia water and adjust the pH of the system to 9. Keep at 50°C and stand for 40h. After the reaction is completed, filter, wash three times with deionized water, and dry at 25°C for 6h to obtain ZrO2-coated microcapsules.

[0040] Example 6: The preparation method of the vitrified microcapsule thermal insulation mortar based on phase change microcapsules is different from that of Example 1. ZrO2 / ZnO composite shell microcapsules are used to replace ZrO2 / ZnO / PDA multi-shell phase change microcapsules in equal amounts. (1) 1.2g core material and 15g formamide are mixed and stirred at 50°C for 40min until the system is uniform. 0.03g CTAB is added and stirred until dissolved. Emulsification is carried out for 15min to obtain an oil-solvent emulsion. 100mL of 0.5mol / L nitric acid solution is added and stirred for 10min. The pH of the system is adjusted to 4. 1.5g zirconium oxychloride is added and stirred at 1000r / min until completely dissolved. Ammonia water is added and the pH of the system is adjusted to 9. The system is kept at 50°C for 40h. After the reaction is completed, the system is filtered, washed three times with deionized water, and dried at 25°C for 6h to obtain ZrO2-coated microcapsules. (2) 1.5g of ZrO2-coated microcapsules were added to 30g of ethanol solution and ultrasonically dispersed at 300W for 30min to obtain a suspension. 0.8g of zinc acetate was added to the suspension and stirred until completely dissolved. Ammonia water was added to adjust the pH of the system to 10. The system was stirred continuously at 1000r / min for 8h. The mixture was filtered, washed three times with deionized water, and dried at 25℃ for 6h to obtain ZrO2 / ZnO composite shell microcapsules.

[0041] Example 7: The preparation method of the vitrified microcapsule thermal insulation mortar based on phase change microcapsules differs from that of Example 1 in that the phenolic resin foam-vitrified microsphere composite material is prepared by Example 2-4.

[0042] Example 8: The preparation method of the vitrified microcapsule thermal insulation mortar based on phase change microcapsules differs from that of Example 1 in that vitrified microspheres are used to replace the phenolic resin foam-vitrified microsphere composite material in an equal amount. Comparative Example

[0043] Comparative Example 1: The preparation method of the vitrified microcapsule thermal insulation mortar based on phase change microcapsules differs from Example 1 in that ZrO2 / ZnO / PDA multi-shell phase change microcapsules are not added.

[0044] Comparative Example 2: The preparation method of the vitrified microcapsule thermal insulation mortar based on phase change microcapsules differs from that of Example 1 in that no phenolic resin foam-vitrified microsphere composite material is added. Performance testing

[0045] Thermal insulation mortar was prepared according to the methods in the examples and comparative examples, and its performance was tested according to the following methods.

[0046] 1. Compressive strength test The compressive strength of the specimens was determined using a universal testing machine. According to the ASTM C165 / C165M-15 standard, the specimens were loaded until failure after 28 days of curing, and the maximum compressive strength was recorded.

[0047] 2. Thermal conductivity test The steady-state thermal resistance of the sample was determined by heat flow meter method, and the thermal conductivity was calculated. The test conditions were a constant temperature environment of 25℃ and a sample thickness of 180μm.

[0048] 3. Combustion performance test The combustion performance is evaluated according to GB / T5464-2010 to determine whether it is a Class A non-combustible material.

[0049] 4. Phase change energy storage efficiency test The phase transition temperature range and energy storage density of the phase change material were determined by differential scanning calorimetry, and the energy storage efficiency was calculated. The test conditions were a heating rate of 10℃ / min.

[0050] In conjunction with Examples 1-4, the thermal insulation mortar prepared in this application has excellent thermal insulation effect and heat storage efficiency.

[0051] Combining Examples 5-6 and Example 1, the thermal conductivity of the insulating mortar prepared in this application increases and the energy storage efficiency decreases. This indicates that by reinforcing the shell structure in stages to form a uniform and dense inorganic shell, the core material can be effectively encapsulated, preventing leakage of the core material during phase change, improving the spectral response range of the microcapsules, and maintaining a high latent heat storage capacity.

[0052] Combining Examples 7 and 1, the thermal insulation mortar prepared in this application exhibits a lower thermal conductivity, higher energy storage efficiency, and higher compressive strength. This indicates that after modification with a silane coupling agent, the vitrified microspheres form a cross-linked structure with cement hydration products, eliminating interfacial micro-gaps, strengthening interfacial adhesion, and improving the overall strength of the mortar.

[0053] Combining Examples 8 and 1, the thermal conductivity of the thermal insulation mortar prepared in this application increases and its energy storage efficiency decreases, indicating that phenolic resin itself is a natural flame-retardant material. When combined with non-flammable inorganic vitrified microspheres, a dual flame-retardant system is formed, consisting of an organic matrix flame retardant and an inorganic filler physical barrier. The closed-cell structure of the phenolic resin foam and the hollow thermal insulation properties of the vitrified microspheres work synergistically, resulting in a relatively lower thermal conductivity, improved thermal insulation effect, and outstanding high-temperature resistance.

[0054] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing vitrified microcapsule thermal insulation mortar based on phase change microcapsules, characterized in that, Includes the following steps: The ZrO2 / ZnO / PDA multi-shell phase change microcapsules, phenolic resin foam-vitrified microsphere composite material, cement, cellulose ether, fly ash, polypropylene fiber, water-reducing agent and redispersible latex powder are dry-mixed for 25-30 seconds to obtain a preliminary mixture. Add water to the preliminary mixture and stir for 60-90 seconds until it is evenly mixed to obtain vitrified microcapsule thermal insulation mortar based on phase change microcapsules.

2. The method for preparing vitrified microcapsule thermal insulation mortar based on phase change microcapsules according to claim 1, characterized in that, The preparation method of the ZrO2 / ZnO / PDA multi-shell phase change microcapsules includes the following steps: (1) After mixing and stirring the core material and formamide at 50°C, add CTAB and stir until dissolved. Emulsify for 10-15 min to obtain an oil-solvent emulsion. Adjust the pH of the system to 3-4, add zirconium oxychloride, adjust the pH of the system to 8-9, keep warm and stand for 36-40 h, filter, wash and dry to obtain ZrO2-coated microcapsules. The mass ratio of core material, formamide, CTAB and zirconium oxychloride is 1-1.2:10-15:0.01-0.03:1.2-1.

5. (2) Disperse ZrO2-coated microcapsules in an ethanol solution, sonicate to obtain a suspension, add zinc acetate to the suspension, stir until dissolved, adjust the pH of the system to 9-10, filter, wash and dry to obtain ZrO2 / ZnO composite shell microcapsules. The mass ratio of ZrO2-coated microcapsules, ethanol solution and zinc acetate is 1-1.5:20-30:0.6-0.

8. (3) Add ZrO2 / ZnO composite shell microcapsules and dopamine hydrochloride to water, sonicate, adjust the pH of the system to 8-9, stir at 23-27℃ for 20-24h under nitrogen protection, filter, wash and dry to obtain ZrO2 / ZnO / PDA multi-shell phase change microcapsules. The mass ratio of ZrO2 / ZnO composite shell microcapsules to dopamine hydrochloride is 10-15:1-3.

3. The method for preparing vitrified microcapsule thermal insulation mortar based on phase change microcapsules according to claim 2, characterized in that, The core material is one or more of n-octadecane, n-eicosane, and n-docosahexadecane.

4. The method for preparing vitrified microcapsule thermal insulation mortar based on phase change microcapsules according to claim 2, characterized in that, The average particle size of the ZrO2 / ZnO / PDA multi-shell phase change microcapsules is 10-35 μm.

5. The method for preparing vitrified microcapsule thermal insulation mortar based on phase change microcapsules according to claim 1, characterized in that, The preparation method of the phenolic resin foam-vitrified microsphere composite material includes the following steps: (1) After mixing and stirring the phenolic resin, polyethylene glycol and foaming agent, p-toluenesulfonic acid is added and stirring is continued. Then, n-pentane is added dropwise to form a foaming precursor. The mass ratio of the phenolic resin, polyethylene glycol, foaming agent, p-toluenesulfonic acid and n-pentane is 100-110:5-8:3-5:4-6:2-4. (2) Add vitrified microspheres to the foaming precursor, stir for 10-15 min to obtain a mixture, keep warm for 30-40 min for initial curing, raise the temperature to 100-110℃, and cure for 2-3 h to obtain phenolic resin foam-vitrified microsphere composite material. The mass ratio of the foaming precursor to the pretreated vitrified microspheres is 6-8:

1.

6. The method for preparing vitrified microcapsule thermal insulation mortar based on phase change microcapsules according to claim 5, characterized in that, The vitrified microspheres undergo the following pretreatment: The vitrified microspheres were sieved, washed, dried, and then added to the hydrolyzed silane coupling agent solution. The mixture was then ultrasonically treated, filtered, and dried.

7. The method for preparing vitrified microcapsule thermal insulation mortar based on phase change microcapsules according to claim 5, characterized in that, The foaming agent is one or more of n-pentane, cyclopentane, water, and methylpentane.

8. The method for preparing vitrified microcapsule thermal insulation mortar based on phase change microcapsules as described in claim 1, characterized in that, The cellulose ether is one or more of hydroxypropyl methylcellulose ether, hydroxyethyl cellulose ether, and methylcellulose ether.