Ultra-low energy consumption residential building floor self-leveling insulation mortar and preparation method thereof

Abstract

The application discloses a super-low energy consumption residential building floor self-leveling thermal insulation mortar and a preparation method thereof, and belongs to the technical field of light building materials. The mortar comprises cement 100 parts, phase change temperature adjusting and heat insulating microcapsules 10-30 parts, vitrified microbeads 150-250 parts and an additive, etc. The microcapsules are prepared by growing a nano-porous silica aerogel shell layer on the surface of a core material through an in-situ mineralization process, wherein the core material is n-octadecane and the precursor is industrial-grade sodium silicate. The application utilizes the Knudsen effect of the nano-pore of the aerogel shell layer to inhibit gas phase heat conduction, and combines the active temperature adjusting function of the latent heat of n-octadecane phase change, so that the mortar has both a super-low thermal conductivity and a heat storage capacity of peak clipping and valley filling. Meanwhile, the inorganic silica shell layer and the cement matrix form a chemical bonding interface through a pozzolanic reaction, effectively improving the mechanical properties and preventing the leakage of the core material. The obtained thermal insulation mortar is suitable for a residential building floor self-leveling thermal insulation system.

Description

Technical Field

[0001] This invention relates to the field of lightweight building materials technology, and in particular to ultra-low energy consumption residential building floor self-leveling thermal insulation mortar and its preparation method. Background Technology

[0002] As building energy efficiency standards become increasingly stringent towards near-zero and ultra-low energy consumption, the thermal insulation performance of floors, as a key interface for indoor heat loss, significantly impacts overall building energy consumption and thermal comfort. Traditional cement-based self-leveling insulation mortars often reduce thermal conductivity by incorporating lightweight aggregates such as vitrified microspheres and expanded perlite. While providing some thermal resistance, this only offers passive insulation and lacks the ability to actively regulate indoor temperature fluctuations. In ultra-low energy consumption residences with large diurnal temperature variations or intermittent heating and cooling, simple thermal resistance insulation is insufficient to smooth out temperature peaks and valleys, leading to increased energy consumption and poor thermal comfort.

[0003] Utilizing the property of phase change materials (PCMs) to absorb or release a large amount of latent heat during phase transitions, introducing them into floor slabs can achieve time-based heat transfer and temperature peak smoothing. Microencapsulation of PCMs is an effective way to solve problems such as incompatibility with cement-based materials and easy leakage. However, existing PCM microcapsules mostly use organic polymer shells such as urea-formaldehyde resin, melamine resin, and polymethyl methacrylate. These shells have low thermal conductivity, severely hindering heat exchange between the core material and the outside environment, resulting in a delayed phase change temperature regulation response. Simultaneously, organic shells have poor hydrophilicity, resulting in weak interfacial bonding with cement paste, easily introducing air bubbles and reducing mortar strength. While some microcapsules with inorganic dense silica shells improve thermal conductivity and strength, they lack the ultra-low thermal conductivity characteristics of a nanoporous structure, thus failing to provide insulation functionality.

[0004] For ultra-low energy consumption residential building floors, there is an urgent need for a new type of functional filler that can efficiently store and release heat, actively regulate temperature, and synergistically enhance thermal insulation performance at the microcapsule level, and use it to construct a thermal insulation mortar system with self-leveling construction characteristics. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing an ultra-low energy consumption self-leveling thermal insulation mortar for residential buildings and its preparation method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention first proposes an ultra-low energy consumption residential building floor self-leveling thermal insulation mortar, which comprises the following components by weight: 100 parts of ordinary Portland cement; 10-30 parts of phase change temperature-regulating and heat-insulating microcapsules; 150-250 parts of vitrified microspheres; 3-5 parts of redispersible latex powder; Hydroxypropyl methylcellulose 0.5–1.0 parts; 0.5 to 1.0 parts of polypropylene fiber; Lignosulfonate 0.2–0.5 parts; 0.5–1.5 parts of organosilicon water-repellent agent; 120-180 parts water; The phase change temperature-regulating and heat-insulating microcapsule has a core-shell structure, with n-octadecane as the core material and an in-situ mineralized nanoporous silica aerogel layer as the shell material.

[0007] Preferably, the preparation method of the phase change temperature-regulating and heat-insulating microcapsules includes the following steps: (1) Sodium silicate is mixed and diluted with water at a mass ratio of 1:3 to 5, sodium ions are removed by passing through a cation exchange resin, and the effluent is collected to obtain an active silica solution with a pH value of 2.5 to 3.5 and a sodium ion residue of ≤100 ppm; (2) After heating and melting n-octadecane, add emulsifier and stir evenly to obtain the oil phase; At 40–45 °C, n-octadecane undergoes a solid-liquid phase transition, changing from a waxy solid to a low-viscosity liquid, with intensified molecular thermal motion. The molecules of the composite emulsifier (Span-80+OP-10) are oriented at the oil-water interface, with the hydrophobic end (long-chain alkyl) inserted into the n-octadecane oil phase and the hydrophilic end (hydroxyl group of Span-80 and polyoxyethylene chain of OP-10) extending into the aqueous phase. High-speed shearing breaks the oil phase into uniform droplets of 0.4–5 μm, and the interfacial film formed by the emulsifier prevents droplet collision and aggregation.

[0008] (3) Add the active silicic acid solution as the aqueous phase to the oil phase and emulsify it at 10,000 to 12,000 rpm for 10 to 15 minutes at 45 to 50°C to form an oil-in-water emulsion; wherein the mass ratio of SiO2 to n-octadecane in the active silicic acid solution is 1 to 5:1. (4) Add dilute acid to the emulsion under stirring to adjust the pH to 2.95-3.05, and react at 45-50℃ for 4-6 hours to allow the active silicic acid to undergo in-situ hydrolysis-condensation reaction on the surface of n-octadecane droplets to generate a silica aerogel shell with a nanoporous structure. When the pH of the emulsion is adjusted to 2.95–3.05, the isoelectric point of silica is approximately pH=2.0. At this point, silicic acid molecules carry a weak negative charge, and the polyoxyethylene chains of emulsifier OP-10 bind to silicic acid molecules through hydrogen bonds.

[0009] This causes silica molecules to preferentially accumulate on the surface of oil droplets, rather than to nucleate homogeneously in the aqueous phase, allowing the shell to grow only on the surface of the core material.

[0010] (5) After the reaction is completed, let it stand for aging for 12 to 24 hours, then centrifuge and wash with deionized water to obtain wet microcapsules; Active silicic acid undergoes a gradual condensation reaction on the surface of oil droplets, and silanol groups are continuously dehydrated to form a three-dimensional porous network with Si-O-Si bonds as the framework. The solvent (water) is encapsulated in the network pores to form a wet gel shell.

[0011] The mass fraction of SiO2 in the active silicic acid solution is controlled at 4% to 6%. The large intermolecular spacing of silicic acid results in a loose network structure rather than dense particles during cross-linking. The reaction temperature of 45 to 50°C ensures a moderate polycondensation rate, allowing sufficient time for silicic acid molecules to spread and grow uniformly on the oil droplet surface, avoiding rapid local aggregation. The orderly arrangement of emulsifier molecules on the oil droplet surface provides a template for the growth of the silica network, guiding the formation of a hierarchical porous structure with a pore size of 2 to 50 nm.

[0012] (6) The wet microcapsules are subjected to surface hydrophobic modification and drying to obtain the phase change temperature regulating and heat insulation microcapsules.

[0013] Preferably, in step (2), the emulsifier is a composite emulsifier of Span-80 and OP-10, wherein the amount of Span-80 is 20% to 25% of the mass of n-octadecane, and the amount of OP-10 is 5% to 10% of the mass of n-octadecane.

[0014] Preferably, in step (6), the surface hydrophobic modification is carried out using a hexane solution of trimethylchlorosilane for 12 to 18 hours; the drying is carried out using segmented drying at atmospheric pressure with a heating rate ≤2℃ / min and a final drying temperature of 120℃.

[0015] This invention also proposes a method for preparing the ultra-low energy consumption residential building floor self-leveling thermal insulation mortar, comprising the following steps: S1. The phase change temperature-regulating and heat-insulating microcapsules were pre-dispersed in water and ultrasonically treated to obtain a uniform microcapsule suspension. S2. Add ordinary silicate cement, redispersible latex powder, hydroxypropyl methylcellulose, lignin sulfonate, organosilicon water-repellent agent and polypropylene fiber into a mixer and dry mix evenly to obtain a dry mix. S3. Add the microcapsule suspension and the remaining water to the dry mixture and stir evenly. Then add the pre-wetted vitrified microspheres in batches and continue stirring until uniform. After standing for 3 to 5 minutes, stir a second time to obtain the thermal insulation mortar.

[0016] Preferably, in step S1, the amount of water used for pre-dispersion is 10% to 20% of the total water volume, the ultrasonic treatment power is 200 to 300W, and the time is 5 to 10 minutes.

[0017] Preferably, the vitrified microspheres are wetted with water at a concentration of 5% to 8% of their mass before being added, and are added in 2 to 3 batches, with stirring for no more than 1 minute after each addition.

[0018] Preferably, in step S2, the dry mixing is carried out using low-speed stirring at a speed of 140±5 rpm for 2 to 3 minutes; in step S3, the stirring after adding the microcapsule suspension and water is carried out using high-speed stirring at a speed of 285±10 rpm for 2 to 3 minutes.

[0019] Preferably, the phase change temperature-regulating and heat-insulating microcapsules have a phase change temperature of 28–30°C, a phase change enthalpy of 95–186 J / g, an average particle size of 0.4–5 μm, a silica aerogel shell with a pore size of 2–50 nm, and a specific surface area ≥500 m². 2 / g.

[0020] Compared with the prior art, the beneficial effects of the present invention are: 1. In existing technologies, the preparation of phase change microcapsules mostly employs in-situ polymerization or interfacial polymerization methods, with shell materials primarily consisting of organic polymers such as melamine resin, urea-formaldehyde resin, or polymethyl methacrylate. The formation mechanism of these organic shells involves free radical polymerization or condensation polymerization of monomers at the oil-water interface. However, the movement of molecular chain segments is restricted, making it difficult to form a completely dense cross-linked network. This results in microporous defects in the shell, making the core material prone to leakage under long-term thermal cycling or mechanical shearing. Furthermore, some studies use pre-prepared silica aerogel powder for physical adsorption composite with phase change materials. This "preparation first, composite later" approach only achieves macroscopic-scale mixing and cannot form an effective core-shell encapsulation structure. The interfacial bonding between the core and shell materials is weak, leading to poor thermal cycling stability. This invention employs an in-situ mineralization growth mechanism: using n-octadecane droplets as a soft template and active silicic acid generated from industrial-grade sodium silicate through ion exchange as a precursor, the pH of the system is precisely controlled to near the isoelectric point of silica (pH 2.95–3.05), allowing silicic acid molecules to undergo a controllable, directional hydrolysis-condensation reaction at the oil-water interface. Under these pH conditions, silicic acid species exist in the form of neutral Si(OH)4, with a moderate condensation rate, enabling them to be deposited layer by layer in an orderly manner on the surface of the n-octadecane droplets, forming a continuous and uniform nanoporous silica aerogel shell. This "growth" process is a self-assembly behavior at the molecular scale. A tightly bonded interfacial transition layer is formed between the shell and the core material through van der Waals forces and hydrogen bonds, eliminating interfacial defects in traditional methods. Simultaneously, the subsequent aging step promotes further cross-linking of siloxane bonds (Si-O-Si), making the shell network more complete and dense, fundamentally eliminating leakage paths in the core material.

[0021] 2. In existing technologies, the incorporation of phase change microcapsules with organic polymer shells into cement-based mortar generally results in a significant decrease in compressive strength. The mechanism lies in the organic polymer shell (surface energy of 20–40 mJ / m²). 2 ) and inorganic cement hydration products (mainly CSH gel and calcium hydroxide, with surface energy >100mJ / m 2 There is an inherent interfacial incompatibility between the microcapsules and the cement paste. This "oil-water" interface leads to two adverse consequences: first, the microcapsules cannot form effective chemical bonds with the cement paste, relying only on weak mechanical interlocking. Under stress, microcracks first form and propagate at the interface, becoming weak areas; second, the elastic modulus of the organic shell (typically <5 GPa) is much lower than that of the cement matrix (20-30 GPa), resulting in significant modulus mismatch under load, causing stress concentration and further accelerating failure. This invention prepares a silica aerogel shell through in-situ mineralization growth. Its chemical nature is amorphous silica, belonging to the same silicate system as the CSH gel in cement hydration products. In the highly alkaline environment of cement hydration, the silanol groups (Si-OH) on the surface of the silica aerogel shell can react with calcium ions generated during cement hydration to produce additional CSH gel in situ, forming a chemically bonded interfacial transition zone between the microcapsules and the cement matrix. This interface layer not only eliminates the modulus mismatch problem, but also transforms the microcapsules from mechanical "defects" into reinforcing phases, thereby ensuring that the mechanical properties of the mortar meet engineering requirements while guaranteeing high-dosage phase change materials.

[0022] 3. The energy-saving mechanism of traditional thermal insulation mortar is based solely on the principle of "thermal resistance," which involves introducing porous lightweight aggregates such as vitrified microspheres and expanded perlite to increase the number of solid-gas interfaces within the material, extending the heat conduction path and thus reducing the thermal conductivity. However, this passive insulation method can only slow down the rate of heat transfer and cannot actively regulate indoor temperature fluctuations. When outdoor temperatures change drastically, the building envelope relying solely on thermal resistance will still cause significant fluctuations in indoor temperature, thereby increasing the load on active cooling or heating. This invention introduces silica shell phase change microcapsules with aerogel nanopore characteristics into the thermal insulation mortar, constructing a dual-effect mechanism of "synergistic enhancement of thermal resistance and heat capacity." On the one hand, the nanopores (pore size 2-50 nm) of the silica aerogel shell are smaller than the mean free path of air molecules (approximately 70 nm), generating the Knudsen effect within the pores. The collision frequency between air molecules and the pore walls is much higher than that between molecules, greatly limiting gas-phase heat conduction and reducing the shell's thermal conductivity to below 0.020 W / (m·K). This forms a composite thermal insulation structure with the vitrified microspheres, lowering the overall thermal conductivity of the mortar to 0.045-0.090 W / (m·K). On the other hand, the phase transition temperature (approximately 28°C) of the core material n-octadecane falls within the comfortable temperature range for the human body. When the indoor temperature rises above 28°C due to sunlight or outdoor heat transfer, n-octadecane melts from a solid to a liquid state, absorbing a large amount of latent heat (95-186 J / g), effectively inhibiting the rapid rise in indoor temperature. When the temperature drops at night, the liquid n-octadecane crystallizes and releases latent heat, slowing down the decrease in indoor temperature. This "peak shaving and valley filling" active temperature regulation function is something that traditional thermal insulation mortars completely lack. The result of the synergistic effect of the two is that the thermal insulation mortar of this invention not only has an ultra-low steady-state thermal conductivity, but also can regulate the indoor thermal environment through latent heat storage and release under dynamic temperature conditions, thereby reducing building energy consumption from both the "heat insulation" and "temperature regulation" dimensions and achieving ultra-low energy consumption. Attached Figure Description

[0023] Figure 1 A schematic diagram of a self-leveling structure for residential floor using the thermal insulation mortar proposed in this invention; In the diagram: 1 is the base layer, 2 is the thermal insulation mortar layer, 3 is the leveling layer, 4 is the surrounding masonry retaining wall, 5 is the underfloor heating pipe layer (including the filling layer), 6 is the finishing layer, and 7 is the fastener. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with existing known technologies. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] Example 1: The ultra-low energy consumption residential building floor self-leveling thermal insulation mortar of this embodiment includes, by weight: 100 parts of ordinary silicate cement (P·O42.5), 15 parts of phase change temperature-regulating and heat-insulating microcapsules, and vitrified microspheres (bulk density 80 kg / m³). 3 200 parts of redispersible latex powder (VAE type), 4 parts of hydroxypropyl methylcellulose (viscosity 100000mPa·s), 0.8 parts of polypropylene fiber (length 6mm), 0.6 parts of sodium lignosulfonate, 1.0 part of organosilicon water-repellent agent (potassium methylsilicate), and 150 parts of water.

[0026] Preparation of the phase change temperature-regulating and heat-insulating microcapsules: (1) Industrial grade sodium silicate was mixed and diluted with water at a mass ratio of 1:4 and passed through a 732 type cation exchange resin column to obtain an active silicic acid solution with pH=3.0 and sodium ion residue of 85ppm. (2) Heat n-octadecane to 42°C to melt it, add 22% of Span-80 and 7% of OP-10 by mass of n-octadecane, and stir at 3000 rpm for 10 minutes to obtain the oil phase; (3) Add active silicic acid solution (SiO2 mass fraction 5%) to the oil phase, with the mass ratio of SiO2 to n-octadecane being 1:3, and emulsify at 11000 rpm for 12 minutes at 48℃ to obtain an oil-in-water emulsion. (4) Add 0.1 mol / L dilute hydrochloric acid to adjust the pH to 3.0, and react at a constant temperature of 48℃ for 5 hours; (5) Let stand for 18 hours, centrifuge at 3000 rpm, and wash twice with deionized water to obtain wet microcapsules; (6) The microcapsules were modified by immersing them in a 15% trimethylchlorosilane-hexane solution for 15 hours. After removal, they were dried in stages under normal pressure. The heating rate was 1.5℃ / min, and the microcapsules were dried at 40℃ for 6 hours, 80℃ for 4 hours, and 120℃ for 2 hours in sequence to obtain phase change temperature-regulating and heat-insulating microcapsules.

[0027] Preparation of thermal insulation mortar: (1) Take 15 parts of water and mix with phase change temperature-regulating and heat-insulating microcapsules, and sonicate at 250W for 8 minutes to obtain a suspension; (2) Add cement, redispersible latex powder, hydroxypropyl methylcellulose, sodium lignosulfonate, organosilicon water-repellent agent and polypropylene fiber into a mixer and dry mix at 140 rpm for 2.5 minutes to obtain dry mix; (3) Add the microcapsule suspension and the remaining 135 parts of water, and stir at 285 rpm for 2.5 minutes; add the vitrified microspheres that have been pre-wetted with 12 parts of water in 3 portions, stirring for 45 seconds each time; let stand for 4 minutes, then stir at 285 rpm for 1 minute to obtain the thermal insulation mortar.

[0028] Example 2: The difference between this embodiment and Embodiment 1 is that the dosage of the phase change temperature regulating and heat insulation microcapsules is 20 parts, the dosage of the vitrified microspheres is 180 parts, and the dosage of water is 145 parts.

[0029] Example 3: The difference between this embodiment and Embodiment 1 is that the dosage of the phase change temperature regulating and heat insulation microcapsules is 25 parts, the dosage of the vitrified microspheres is 160 parts, and the dosage of water is 140 parts.

[0030] The following comparison model was also set: Comparative Example 1: This comparative example is ordinary vitrified microsphere thermal insulation mortar, with the following formula: 100 parts ordinary silicate cement, 200 parts vitrified microspheres, 4 parts redispersible latex powder, 0.8 parts hydroxypropyl methylcellulose, 0.6 parts polypropylene fiber, 0.3 parts sodium lignosulfonate, 1.0 part organosilicon water-repellent agent, and 150 parts water.

[0031] Comparative Example 2: This comparative example uses commercially available melamine-formaldehyde shell n-octadecane phase change microcapsules (phase change enthalpy 160 J / g), with a dosage of 15 parts. The remaining formulation and preparation method are the same as in Example 1.

[0032] Performance testing: Performance tests were conducted on the thermal insulation mortars prepared in the above embodiments and comparative examples. The thermal insulation mortars were prepared according to... Figure 1 The thermal conductivity of the ground was tested using the structure shown in the table below.

[0033] Data Analysis: In terms of mechanics and durability, the mortar of this invention has a 28-day compressive strength of 7.9-9.2 MPa, which is 16%-35% higher than that of Comparative Example 2; the strength loss rate after 100 cycles of hot and cold is only 4.8%-5.7%, which is less than 1 / 3 of that of Comparative Example 2, thus solving the pain points of poor interfacial bonding, easy breakage during stirring, and long-term leakage and aging of traditional organic shell microcapsules.

[0034] In terms of thermal performance, the thermal conductivity of the mortar of this invention is as low as 0.054-0.058 W / (m・K), which is 6%-13% lower than that of Comparative Example 1; the phase change enthalpy increases linearly with the amount of microcapsule doping to 21.8-34.6 J / g, achieving a dual passive temperature regulation effect of porous insulation and latent heat storage.

[0035] The mortar of this invention has significant advantages in heat and moisture resistance and mildew resistance. Its volume water absorption rate is only 6.2%-6.8%, which is about 50% of that of traditional products. Its mildew resistance level reaches the highest level 0. The hydrophobic silica aerogel shell blocks the accumulation of moisture inside the mortar, which greatly reduces the possibility of mold growth.

[0036] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. Ultra-low energy consumption residential building floor self-leveling thermal insulation mortar, characterized in that, It includes the following components in parts by weight: 100 parts of ordinary Portland cement; 10-30 parts of phase change temperature-regulating and heat-insulating microcapsules; 150-250 parts of vitrified microspheres; 3-5 parts of redispersible latex powder; Hydroxypropyl methylcellulose 0.5–1.0 parts; 0.5 to 1.0 parts of polypropylene fiber; Lignosulfonate 0.2–0.5 parts; 0.5–1.5 parts of organosilicon water-repellent agent; 120-180 parts water; The phase change temperature-regulating and heat-insulating microcapsule has a core-shell structure, with n-octadecane as the core material and an in-situ mineralized nanoporous silica aerogel layer as the shell material.

2. The ultra-low energy consumption residential building floor self-leveling thermal insulation mortar according to claim 1, characterized in that, The preparation method of the phase change temperature-regulating and heat-insulating microcapsules includes the following steps: (1) Sodium silicate is mixed and diluted with water at a mass ratio of 1:3 to 5, sodium ions are removed by passing through a cation exchange resin, and the effluent is collected to obtain an active silica solution with a pH value of 2.5 to 3.5 and a sodium ion residue of ≤100 ppm; (2) After heating and melting n-octadecane, add emulsifier and stir evenly to obtain the oil phase; (3) Add the active silicic acid solution as the aqueous phase to the oil phase and emulsify it at 10,000 to 12,000 rpm for 10 to 15 minutes at 45 to 50°C to form an oil-in-water emulsion; wherein the mass ratio of SiO2 to n-octadecane in the active silicic acid solution is 1 to 5:

1. (4) Add dilute acid to the emulsion under stirring to adjust the pH to 2.95-3.05, and react at 45-50℃ for 4-6 hours to allow the active silicic acid to undergo in-situ hydrolysis-condensation reaction on the surface of n-octadecane droplets to generate a silica aerogel shell with a nanoporous structure. (5) After the reaction is completed, let it stand for aging for 12 to 24 hours, then centrifuge and wash with deionized water to obtain wet microcapsules; (6) The wet microcapsules are subjected to surface hydrophobic modification and drying to obtain the phase change temperature regulating and heat insulation microcapsules.

3. The ultra-low energy consumption residential building floor self-leveling thermal insulation mortar according to claim 2, characterized in that, In (2), the emulsifier is a composite emulsifier of Span-80 and OP-10, with Span-80 accounting for 20% to 25% of the mass of n-octadecane and OP-10 accounting for 5% to 10% of the mass of n-octadecane.

4. The ultra-low energy consumption residential building floor self-leveling thermal insulation mortar according to claim 2, characterized in that, In step (6), the surface hydrophobic modification is carried out using a hexane solution of trimethylchlorosilane for 12 to 18 hours; the drying is carried out using segmented drying at atmospheric pressure with a heating rate ≤2℃ / min and a final drying temperature of 120℃.

5. A method for preparing the ultra-low energy consumption residential building floor self-leveling thermal insulation mortar according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. The phase change temperature-regulating and heat-insulating microcapsules were pre-dispersed in water and ultrasonically treated to obtain a uniform microcapsule suspension. S2. Add ordinary silicate cement, redispersible latex powder, hydroxypropyl methylcellulose, lignin sulfonate, organosilicon water-repellent agent and polypropylene fiber into a mixer and dry mix evenly to obtain a dry mix. S3. Add the microcapsule suspension and the remaining water to the dry mixture and stir evenly. Then add the pre-wetted vitrified microspheres in batches and continue stirring until uniform. After standing for 3 to 5 minutes, stir a second time to obtain the thermal insulation mortar.

6. The preparation method according to claim 5, characterized in that, In S1, the amount of water used for pre-dispersion is 10% to 20% of the total water consumption, the ultrasonic treatment power is 200 to 300W, and the time is 5 to 10 minutes.

7. The preparation method according to claim 5, characterized in that, Before adding the vitrified microspheres, wet the surface with water equivalent to 5% to 8% of their mass, and add them in 2 to 3 times, stirring for no more than 1 minute after each addition.

8. The preparation method according to claim 5, characterized in that, In step S2, the dry mixing is carried out using low-speed stirring at a speed of 140±5 rpm for 2 to 3 minutes; in step S3, the stirring after adding the microcapsule suspension and water is carried out using high-speed stirring at a speed of 285±10 rpm for 2 to 3 minutes.

9. The preparation method according to claim 5, characterized in that, The phase change temperature-regulating and heat-insulating microcapsules have a phase change temperature of 28–30℃, a phase change enthalpy of 95–186 J / g, an average particle size of 0.4–5 μm, a silica aerogel shell with a pore size of 2–50 nm, and a specific surface area ≥500 m². 2 / g.

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