Phase change energy storage thermal insulation mortar and preparation method thereof

Abstract

The invention relates to the technical field of green building materials, in particular to phase-change energy-storage thermal insulation mortar and a preparation method of the phase-change energy-storage thermal insulation mortar. 25 to 40 parts of methyl palmitate; 120 to 180 parts of hydrophobic perlite; 8 to 15 parts of expanded graphite; 3-6 parts of phosphorus sheet-shaped aluminum nitride; 180 to 250 parts of sulphoaluminate cement; 60 to 100 parts of volcanic rock micro powder; 0.3 to 0.8 part of hydroxypropyl methyl cellulose; 0.6 to 1.2 parts of a polycarboxylic acid water reducing agent; 2 to 4 parts of nano aluminum oxide; 0.8 to 1.5 parts of propyl gallate; and 1-2 parts of zinc borate. Through the proportion design of the antioxidant flame-retardant microcapsules and the lightweight composite aggregate, the problems of poor thermal conductivity and insufficient durability of a traditional phase change material are solved. Through phase change material loading, interface modification and multi-component cooperative regulation, the thermal insulation performance, energy storage efficiency and structural stability are remarkably improved, and the material is suitable for the fields of building energy saving, intelligent temperature control and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of green building materials, in particular to a phase change energy storage insulation mortar and a preparation method thereof. BACKGROUND

[0002] Phase change energy storage insulation mortar has important application value in the field of building energy saving. Its core requirement is to realize dynamic regulation of indoor temperature of buildings through latent heat absorption and release of phase change materials, thereby reducing energy consumption of air conditioning or heating systems. At the same time, the material needs to maintain stable physical and chemical properties in long-term cyclic use, avoiding functional failure due to leakage, phase separation or thermal conductivity decay. In addition, the preparation process needs to be compatible with the existing building construction process, and the material cost needs to be controlled within a reasonable range to promote large-scale engineering application.

[0003] The existing solutions that are targeted at this technical requirement are as follows: Hydrated salt phase change material composite mortar: taking hydrated salt such as sodium sulfate decahydrate as the core material, loaded by porous substrate, and using its high phase change enthalpy to improve energy storage efficiency.

[0004] Gel encapsulation of phase change materials: using silica gel network to wrap paraffin, forming dense microcapsules, and adjusting the gel pore size to control the release rate of phase change materials, which is suitable for precise equipment insulation that requires precise temperature control.

[0005] Biomass-based phase change composite material: composite of plant cellulose and paraffin, using the porous structure of cellulose to improve the coating rate of phase change materials, and using the renewability of natural materials to reduce environmental burden.

[0006] Although the above solutions have made progress in specific scenarios, there are still the following problems: Insufficient phase change stability: hydrated salt is prone to lose crystal water during repeated heat absorption and release, resulting in phase change temperature drift and energy storage capacity decline, and salt precipitation phenomenon occurs after long-term use, damaging the structural integrity of the mortar.

[0007] Complex process and high cost: gel method relies on high-purity silica raw materials and precise reaction condition control, resulting in significant increase in production cost, and the gel network is prone to cracking at high temperature, affecting the long-term storage effect of phase change materials.

[0008] Limited thermal performance of biomass-based materials: the interfacial bonding force between plant cellulose and paraffin is weak, and phase separation occurs at high temperature, and the thermal stability of biomass materials is poor, which may lead to decomposition of the composite material in long-term use, reducing the overall durability. SUMMARY

[0009] In view of the deficiencies of the prior art, the present application provides a phase change energy storage thermal insulation mortar and a preparation method thereof, which solve the problems of the prior art.

[0010] According to a first aspect of the present application, a phase change energy storage thermal insulation mortar is provided, which is composed of the following components in mass fraction: Paraffin wax: 80-120 parts; Methyl palmitate: 25-40 parts; Hydrophobic perlite: 120-180 parts; Expanded graphite: 8-15 parts; Flake-like aluminum nitride: 3-6 parts; Sulphate cement: 180-250 parts; Volcanic rock powder: 60-100 parts; Hydroxypropyl methylcellulose: 0.3-0.8 parts; Polycarboxylic acid water reducer: 0.6-1.2 parts; Nano-aluminum oxide: 2-4 parts; Propyl gallate: 0.8-1.5 parts; Zinc borate: 1-2 parts.

[0011] Paraffin wax (PW) as the core energy storage medium of phase change material, absorbs or releases a large amount of latent heat through the solid-liquid phase change process, realizes dynamic adjustment of the building environment temperature, and reduces the energy consumption of air conditioning or heating system.

[0012] Expanded graphite (EG) is used to enhance the thermal conductivity of the material, and through the high thermal conductivity and thermal radiation characteristics of the graphite sheet layer, the heat transfer between the phase change material and the matrix is promoted, and the thermal hysteresis effect in the phase change process is reduced.

[0013] Flake-like aluminum nitride (AN) is used to improve the thermal conductivity of the composite material, and the high thermal conductivity and flaky structure of aluminum nitride are used to form a heat conduction path in the mortar, accelerating the dispersion and release of heat between the phase change material and the cement matrix.

[0014] Hydroxypropyl methylcellulose (HPMC) is used to improve the workability and water retention of the mortar, and the high molecular chain of the cellulose ether forms a viscoelastic film in water, prolonging the open time of the mortar and reducing water evaporation, ensuring the construction adaptability.

[0015] Nano Aluminum Oxide (Al2O3) is used to improve the durability and compressive strength of the material. The high specific surface area and surface activity of nano aluminum oxide can fill the micropores of the cement matrix, inhibit crack propagation, and enhance the density of the interface transition zone.

[0016] Zinc Borate (ZB) is used to enhance the fire resistance of the material. When heated, zinc borate releases crystal water and forms a glassy protective layer, which insulates oxygen and heat transfer, and inhibits the pyrolysis reaction of combustible materials, reducing the risk of fire.

[0017] According to the embodiments of the present application, by synergistic energy storage and temperature regulation of paraffin and methyl palmitate, hydrophobic perlite carries phase change material, expanded graphite and aluminum nitride construct a heat conduction network, sulfaluminate cement and volcanic rock provide structural strength, hydroxypropyl methyl cellulose optimizes construction performance, nano aluminum oxide enhances durability, and zinc borate improves fire resistance, achieving multi-dimensional balance of energy saving, heat conduction and safety.

[0018] According to the embodiments of the present application, the methyl palmitate is a transparent solution obtained by esterification of palmitic acid and methanol; the hydrophobic perlite is a light yellow powder obtained by soaking and modifying the perlite in a silane coupling agent with a concentration of 0.5-1.0wt%, and then drying; The molar ratio of the palmitic acid to the methanol is 1:1.2-1:1.5; The mass ratio of the perlite to the silane coupling agent is 100:0.5-100:1.

[0019] Methyl palmitate (MP) is used to optimize the phase change temperature range and form a mixed phase change system with paraffin, by adjusting the molecular chain length and melting point, the phase change temperature is closer to the human comfortable temperature interval, and the temperature regulation efficiency is improved.

[0020] Hydrophobic perlite (HP) is used as a porous carrier to load phase change material, using the porous structure of perlite to adsorb paraffin and methyl palmitate, and preventing phase change material leakage by surface hydrophobic treatment, avoiding phase change material migration or pollution caused by capillary phenomenon after long-term use.

[0021] According to the embodiments of the present application, by forming a mixed phase change system of methyl palmitate and paraffin, the phase change temperature is adjusted to the human comfortable interval by the difference in molecular chain length, and the temperature regulation efficiency is improved. At the same time, the hydrophobic perlite modified by silane coupling agent is used as a porous carrier, which not only fixes the phase change material by physical adsorption, but also blocks the capillary migration path by surface hydrophobization, effectively preventing phase change material leakage or pollution in long-term circulation.

[0022] According to the embodiment of the present application, the expanded graphite is black porous particles mixed from natural graphite and intercalation agent; the sulfoaluminate cement is gray powder mixed from sulfoaluminate clinker and gypsum; and the volcanic rock micropowder is milky white powder calcined from volcanic rock at high temperature of 800-900℃. The mass ratio of the natural graphite to the intercalation agent is 100:5-100:8, and the intercalation agent is a complex solution mixed from potassium bisulfate and hydrogen peroxide at a mass ratio of 1:2-1:3. The mass ratio of the sulfoaluminate clinker to the gypsum is 95:5-100:5.5.

[0023] The sulfoaluminate cement (SAC) provides structural strength and fast hardening performance as a cementitious material, and a stable ettringite crystal network is formed through the rapid hydration reaction of the sulfoaluminate cement, so as to enhance the mechanical properties of the mortar and shorten the construction period.

[0024] The volcanic rock micropowder (VRM) is used to fill the pores of the matrix and improve the thermal stability, and the pozzolanic activity of the volcanic rock micropowder can react with the cement hydration products to generate a dense structure, and the low thermal conductivity of the volcanic rock micropowder further reduces the overall heat conduction rate of the mortar.

[0025] According to the embodiment of the present application, through the synergistic effect of the high-thermal-conductivity sheet structure of the expanded graphite and the rapid hydration reaction of the sulfoaluminate cement, the former builds a heat conduction path to accelerate heat transfer, and the latter forms an ettringite crystal network to provide structural strength and shorten the period. Meanwhile, the volcanic rock micropowder reacts with the cement hydration products to generate a dense structure through the pozzolanic activity, and the low thermal conductivity further reduces the overall heat conduction rate.

[0026] According to the embodiment of the present application, the polycarboxylate superplasticizer is a high-molecular-weight water-reducing solution copolymerized from acrylic acid, maleic anhydride and polyoxyethylene ether monomer; the propyl gallate is a white crystalline powder esterified from gallic acid and propanol; and the zinc borate is a hexagonal crystal system powder mixed from zinc oxide and boric acid at high temperature of 800-900℃. The molar ratio of the acrylic acid, the maleic anhydride and the polyoxyethylene ether monomer is 2:1:1-3:1:1. The molar ratio of the gallic acid to the propanol is 1:1.5-1:2. The mass ratio of the zinc oxide to the boric acid is 1:1-1:1.2.

[0027] Polycarboxylate superplasticizer (PCE) is used to reduce the water content of mortar and enhance the fluidity, by adsorbing on the surface of cement particles through the comb-shaped molecular chain of superplasticizer, producing electrostatic repulsion and steric hindrance effect, dispersing particle aggregation and improving the homogeneity of the slurry.

[0028] Propyl gallate (PG) is used to delay the oxidative degradation of phase change materials, by reacting with free radicals through the phenolic hydroxyl group of propyl gallate, interrupting the oxidative chain reaction, thereby prolonging the thermal cycle stability of the phase change material.

[0029] According to the embodiments of the present application, the polycarboxylate superplasticizer, propyl gallate and zinc borate synergistically realize the simultaneous optimization of mortar construction adaptability, phase change material durability and fireproof performance, providing a comprehensive solution for phase change energy storage systems with high-efficiency dispersion, oxidation resistance and flame retardation.

[0030] According to the second aspect of the present application, a preparation method of the above-mentioned phase change energy storage insulation mortar is provided, as shown in Figure 1 the steps include: S1: melt blending the paraffin wax and the methyl palmitate, then adding the expanded graphite and the phosphorus flaky aluminum nitride to prepare a phase change energy storage compound; S2: dry mixing the hydrophobic perlite and the nano-alumina, then preparing a light composite aggregate by a high-pressure forming process; S3: mixing the sulphoaluminate cement, the volcanic rock micro-powder, the hydroxypropyl methyl cellulose and the polycarboxylate superplasticizer to prepare a cementitious slurry; S4: mixing the propyl gallate and the zinc borate to prepare an antioxidant and flame-retardant microcapsule; S5: mixing the phase change energy storage compound, the light composite aggregate, the cementitious slurry and the antioxidant and flame-retardant microcapsule, then pouring into a mold to prepare the phase change energy storage insulation mortar.

[0031] According to the embodiments of the present application, the melt blending of the paraffin wax and the methyl palmitate, then adding the expanded graphite and the phosphorus flaky aluminum nitride to prepare a phase change energy storage compound includes: The paraffin wax and the methyl palmitate are put into a melting kettle according to a mass ratio of 3:1-4:1, heated to 80-90℃, the stirring speed is 300-500rpm, and stirring for 1-2 hours to obtain a melt blending liquid; The expanded graphite and the phosphorus flaky aluminum nitride are added to the melt blending liquid, and dispersed for 10-20 minutes under the condition of ultrasonic power 300-500W to prepare the phase change energy storage compound; The mass ratio of the melt-blended liquid, the expanded graphite and the phosphorus flaky aluminum nitride is 100:8:3-100:15:6.

[0032] According to the embodiment of the present application, a mixed phase change system is formed by melt-blending of paraffin and methyl palmitate to optimize the phase change temperature range. After adding expanded graphite and phosphorus flaky aluminum nitride, a three-dimensional heat conduction network is constructed by using its high thermal conductivity to accelerate the dispersion and release of heat in the composite material. The ultrasonic-assisted dispersion process can effectively break the agglomeration and ensure the uniform combination of the phase change material and the heat-conducting filler, improving the interface compatibility.

[0033] According to the embodiment of the present application, the dry mixing of the hydrophobic perlite and the nano-alumina, and the preparation of the lightweight composite aggregate by high-pressure forming process include: The hydrophobic perlite and the nano-alumina are put into a high-speed mixer at a mass ratio of 10:1-10:3, mixed at a speed of 80-100 rpm for 5-10 minutes to obtain a mixture; The mixture is placed in a vacuum impregnation tank, vacuumized to a pressure of-0.09 to-0.10 MPa, deionized water is injected to saturation, the pressure is adjusted to 10-12 MPa, and after pressing for 30-35 seconds, drying treatment is performed to prepare the lightweight composite aggregate.

[0034] According to the embodiment of the present application, the lightweight composite aggregate has low thermal conductivity and excellent mechanical properties, can maintain the building insulation requirements, and through the reinforcing effect of nano-alumina, the compressive strength and durability are improved, providing a composite framework material with lightweight, structural stability and thermal insulation performance for phase change energy storage mortar.

[0035] According to the embodiment of the present application, the mixing of the sulphoaluminate cement, the volcanic rock powder, the hydroxypropyl methyl cellulose and the polycarboxylic acid superplasticizer to prepare a cementitious paste includes: The sulphoaluminate cement and the volcanic rock powder are put into a planetary mixer at a mass ratio of 3:1-4:1, mixed at a speed of 20-30 rpm for 10-15 minutes to obtain a basic mixture; The basic mixture, the hydroxypropyl methyl cellulose, the polycarboxylic acid superplasticizer and deionized water are mixed at a mass ratio of 98:0.3:0.6:30-99:0.8:1.2:35, stirred at a speed of 120-150 rpm for 10-15 minutes to prepare the cementitious paste.

[0036] According to the embodiment of the present application, by mixing the sulphoaluminate cement and the volcanic rock micro-powder in proportion to form the base aggregate, combining the water retention and thickening effect of hydroxypropyl methyl cellulose and the dispersion efficiency of polycarboxylic acid water reducing agent, the performance of the cementitious slurry is synergistically optimized. Under the precise control of the mixing ratio and the stirring process, the cementitious slurry realizes the comprehensive performance of high density, excellent construction adaptability and long-term thermal stability.

[0037] According to the embodiment of the present application, the mixing of the propyl gallate and the zinc borate to prepare the antioxidant and flame-retardant microcapsule includes: The propyl gallate and the zinc borate are put into a high-speed shearing machine in a mass ratio of 1:1.5-1:2, and sheared at a rotating speed of 8000-10000 rpm for 10-20 minutes to obtain a mixed solution; The mixed solution is subjected to spray drying, the air inlet temperature is controlled at 180-200 DEG C, the air outlet temperature is controlled at 80-90 DEG C, and the atomization pressure is controlled at 0.4-0.6 MPa to prepare the antioxidant and flame-retardant microcapsule.

[0038] According to the embodiment of the present application, the high-speed shearing process ensures uniform dispersion, and the spray drying technology quickly solidifies the mixed solution into a microcapsule structure, which realizes the integration of antioxidant and flame-retardant functions and improves the stability of components through microcapsule packaging. The finally prepared antioxidant and flame-retardant microcapsule can simultaneously improve the durability and safety of the phase change energy storage system, and meet the dual requirements of long-term thermal cycle stability and fireproof performance of building energy-saving materials.

[0039] According to the embodiment of the present application, the mixing of the phase change energy storage compound, the light composite aggregate, the cementitious slurry and the antioxidant and flame-retardant microcapsule, and then pouring into a mold to prepare the phase change energy storage thermal insulation mortar includes: The phase change energy storage compound and the light composite aggregate are sequentially put into a forced mixer in a mass ratio of 60:20-65:18, and mixed under the stirring condition of a rotating speed of 20-30 rpm for 5-10 minutes to obtain an initial mixture; The initial mixture, the cementitious slurry and the antioxidant and flame-retardant microcapsule are mixed in a mass ratio of 70:15:10-78:13:9, and stirred at a rotating speed of 80-100 rpm for 3-5 minutes to prepare a mixed slurry; The mixed slurry is poured into a mold, and cured at a temperature of 20-25 DEG C for 28-30 days, and after demolding, the phase change energy storage thermal insulation mortar is obtained.

[0040] According to the embodiment of the present application, by proportionally compounding the phase change energy storage compound with the light weight composite aggregate, combining the bonding performance of the cementitious paste and the protection function of the antioxidant and flame-retardant microcapsule, a phase change energy storage insulation mortar system is constructed. The phase change compound provides dynamic temperature regulation capability, the light weight aggregate reduces the overall density and enhances the structural stability, the cementitious paste forms a skeleton strength through the rapid hydration of the sulphoaluminate cement, and the antioxidant and flame-retardant microcapsule simultaneously delays the aging of the phase change material and improves the fireproof performance.

[0041] The present application has the following beneficial effects: The present application significantly improves the flame-retardant performance and safety level of the material through a double protection mechanism. Zinc borate releases crystal water at high temperature and forms a dense protective layer to isolate oxygen and heat transfer. Propyl gallate delays the decomposition of the phase change material through antioxidant action, and the two together construct a physical and chemical synergistic flame-retardant system, effectively delaying the spread of combustion and reducing the risk of fire, meeting the needs of building scenes with high safety requirements.

[0042] The present application significantly improves the temperature regulation efficiency and long-term stability of the phase change energy storage insulation mortar through multi-component compounding design. Paraffin and methyl palmitate form a mixed phase change system, accurately regulating the phase change temperature to the human comfort interval, achieving dynamic balance of the building environment temperature. Hydrophobic perlite effectively fixes the phase change material through surface modification technology, avoiding migration and pollution, and ensuring that the material does not degrade in performance in long-term circulation.

[0043] The present application significantly enhances the thermal response rate and cycle durability of the material by constructing a three-dimensional heat conduction network. The synergistic introduction of expanded graphite and phosphorus flaky aluminum nitride forms a continuous heat conduction path, accelerating the dispersion and release of heat in the composite system, significantly shortening the thermal hysteresis time of the phase change process. Nano-alumina further strengthens the interfacial bonding force, inhibits the expansion of micro-cracks, and improves the fatigue resistance of the material.

[0044] The present application realizes the balance of structural strength and construction efficiency by optimizing the compatibility of the cementitious system and construction. The compounding of sulphoaluminate cement and volcanic rock powder provides rapid hardening ability and high compressive strength, meeting the bearing requirements of building structures. The synergistic effect of hydroxypropyl methyl cellulose and polycarboxylic acid superplasticizer prolongs the paste open time and reduces the water consumption, ensuring the stable control of material fluidity and forming quality in construction.

[0045] The present application realizes the unity of environmental performance and resource sustainability by selecting natural and renewable raw materials and low energy consumption process. The combination of volcanic rock powder, plant-based additives and inorganic flame retardant reduces the dependence on petrochemical resources, and the material is environmentally friendly after being discarded. The whole preparation process adopts normal temperature curing and high efficiency dispersion technology, reducing energy consumption and pollution emission, which meets the industry trend of green building and low carbon development.

[0046] Of course, implementing any product of the application does not necessarily require achieving all of the above-mentioned advantages at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 Flow chart of the preparation method of the embodiment of the application. DETAILED DESCRIPTION

[0048] The embodiment of the application provides a phase change energy storage thermal insulation mortar and a preparation method thereof.

[0049] Example 1: standard formula phase change energy storage thermal insulation mortar Paraffin wax: 100 parts; Methyl palmitate: 30 parts; Hydrophobic perlite: 150 parts; Expanded graphite: 10 parts; Phosphorus flaky aluminum nitride: 4 parts; Sulphate cement: 200 parts; Volcanic rock powder: 80 parts; Hydroxypropyl methyl cellulose: 0.5 parts; Polycarboxylic acid water reducer: 0.9 parts; Nano-aluminum oxide: 3 parts; Propyl gallate: 1 part; Zinc borate: 1.5 parts.

[0050] Example 2: increase the content of paraffin wax Paraffin wax: 120 parts; Methyl palmitate: 30 parts; Hydrophobic perlite: 150 parts; Expanded graphite: 10 parts; Phosphorus flaky aluminum nitride: 4 parts; Sulphate cement: 200 parts; Volcanic rock powder: 80 parts; Hydroxypropyl methyl cellulose: 0.5 parts; Polycarboxylic acid water reducer: 0.9 parts; Nano-aluminum oxide: 3 parts; Propyl gallate: 1 part; Zinc borate: 1.5 parts.

[0051] Example 3: reduce the content of methyl palmitate Paraffin wax: 100 parts; Methyl palmitate: 25 parts; Hydrophobic perlite: 150 parts; Expanded graphite: 10 parts; Phosphorus flaky aluminum nitride: 4 parts; Sulphate cement: 200 parts; Volcanic rock powder: 80 parts; Hydroxypropyl methylcellulose: 0.5 parts; Polycarboxylic acid water reducer: 0.9 parts; Nano-alumina: 3 parts; Propyl gallate: 1 part; Zinc borate: 1.5 parts.

[0052] Example 4: Enhancement of thermal conductivity Paraffin wax: 100 parts; Methyl palmitate: 30 parts; Hydrophobic perlite: 150 parts; Expanded graphite: 15 parts; Phosphorus flaky aluminum nitride: 6 parts; Sulphoaluminate cement: 200 parts; Volcanic rock powder: 80 parts; Hydroxypropyl methylcellulose: 0.5 parts; Polycarboxylic acid water reducer: 0.9 parts; Nano-alumina: 4 parts; Propyl gallate: 1 part; Zinc borate: 1.5 parts.

[0053] Example 5: Optimization of fireproof performance Paraffin wax: 100 parts; Methyl palmitate: 30 parts; Hydrophobic perlite: 150 parts; Expanded graphite: 10 parts; Phosphorus flaky aluminum nitride: 4 parts; Sulphoaluminate cement: 200 parts; Volcanic rock powder: 80 parts; Hydroxypropyl methylcellulose: 0.5 parts; Polycarboxylic acid water reducer: 0.9 parts; Nano-alumina: 3 parts; Propyl gallate: 1.5 parts; Zinc borate: 2 parts.

[0054] Example 6: Improvement of mechanical strength Paraffin wax: 100 parts; Methyl palmitate: 30 parts; Hydrophobic perlite: 180 parts; Expanded graphite: 10 parts; Phosphorus flaky aluminum nitride: 4 parts; Sulphoaluminate cement: 250 parts; Volcanic rock powder: 100 parts; Hydroxypropyl methylcellulose: 0.8 parts; Polycarboxylic acid water reducing agent: 1.2 parts; Nano-alumina: 4 parts; Propyl gallate: 1 part; Zinc borate: 1.5 parts.

[0055] Comparative Example 1: No hydrophobic perlite Paraffin wax: 100 parts; Methyl palmitate: 30 parts; Expanded graphite: 10 parts; Phosphorus flaky aluminum nitride: 4 parts; Sulphoaluminate cement: 200 parts; Volcanic rock micro powder: 80 parts; Hydroxypropyl methyl cellulose: 0.5 parts; Polycarboxylic acid water reducing agent: 0.9 parts; Nano-alumina: 3 parts; Propyl gallate: 1 part; Zinc borate: 1.5 parts.

[0056] Comparative Example 2: No expanded graphite Paraffin wax: 100 parts; Methyl palmitate: 30 parts; Hydrophobic perlite: 150 parts; Phosphorus flaky aluminum nitride: 4 parts; Sulphoaluminate cement: 200 parts; Volcanic rock micro powder: 80 parts; Hydroxypropyl methyl cellulose: 0.5 parts; Polycarboxylic acid water reducing agent: 0.9 parts; Nano-alumina: 3 parts; Propyl gallate: 1 part; Zinc borate: 1.5 parts.

[0057] Comparative Example 3: No propyl gallate Paraffin wax: 100 parts; Methyl palmitate: 30 parts; Hydrophobic perlite: 150 parts; Expanded graphite: 10 parts; Phosphorus flaky aluminum nitride: 4 parts; Sulphoaluminate cement: 200 parts; Volcanic rock micro powder: 80 parts; Hydroxypropyl methyl cellulose: 0.5 parts; Polycarboxylic acid water reducing agent: 0.9 parts; Nano-alumina: 3 parts; Zinc borate: 1.5 parts.

[0058] ​​​​Comparative Example 4: Without zinc borate Paraffin wax: 100 parts; Methyl palmitate: 30 parts; Hydrophobic perlite: 150 parts; Expanded graphite: 10 parts; Phosphorus flaky aluminum nitride: 4 parts; Sulphoaluminate cement: 200 parts;

[0059] Volcanic rock powder: 80 parts; Hydroxypropyl methyl cellulose: 0.5 parts; Polycarboxylic acid water reducer: 0.9 parts; Nano-alumina: 3 parts; Propyl gallate: 1 part.

[0060] Experimental Examples: The properties of Examples 1-6 and Comparative Examples 1-4 were determined based on the above, and the results are shown in Table 1. They include: 1. Compressive strength test

[0061] The compressive strength of the test block was determined using a universal testing machine, and according to the ASTM C165 / C165M-15 standard, the test block was loaded to failure after 28 days of curing, and the maximum compressive strength was recorded.

[0062] 2. Thermal conductivity test

[0063] The steady-state thermal resistance of the test block was determined by the heat flow meter method, and the thermal conductivity was calculated. The test conditions were a constant temperature environment of 25°C, and the sample thickness was 180 μm.

[0064] 3. Water absorption test

[0065] The mass change rate of the test block after being immersed in water for 24 hours was determined by the dry-wet weight method, and the water absorption was calculated.

[0066] 4. Linear shrinkage rate test

[0067] According to the GB / T5486-2008 standard, the length change of the test block before and after drying was measured, and the shrinkage rate was calculated.

[0068] 5. Combustion performance test

[0069] The combustion performance was evaluated according to GB / T5464-2010, and it was determined whether it was a Class A non-combustible material.

[0070] 6. Phase change energy storage efficiency test

[0071] The phase change 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 temperature rise rate of 10°C / min.

[0072] Table 1. Experimental data of examples 1-6 and comparative examples 1-4 of the present application Sample Compressive strength (MPa) Thermal conductivity (W / (m-K)) Water absorption (%) Linear shrinkage (%) Combustion performance grade Phase change energy storage efficiency (J / g) Example 1 28.5 0.068 8.2 0.25 Grade A 158 Example 2 27.3 0.071 8.5 0.27 Grade A 165 Example 3 29.1 0.065 7.8 0.23 Grade A 152 Example 4 26.8 0.059 8.1 0.24 Grade A 160 Example 5 27.9 0.067 8.0 0.25 Grade A 156 Example 6 32.4 0.063 7.5 0.20 Grade A 168 Comparative Example 1 22.1 0.082 9.3 0.30 Grade A 135 Comparative Example 2 19.8 0.091 10.1 0.35 Grade A 120 Comparative Example 3 23.7 0.078 9.0 0.28 Grade A 142 Comparative Example 4 21.5 0.085 9.2 0.32 Grade A 138

[0073] From Table 1, the compressive strength is: Example 6 (improve mechanical strength) significantly improves the compressive strength to 32.4 MPa, indicating the synergistic effect of hydrophobic perlite, sulphoaluminate cement and volcanic rock powder; Comparative Example 1 (without hydrophobic perlite) or Comparative Example 2 (without expanded graphite) leads to a significant decrease in compressive strength, indicating that lightweight aggregate is crucial for structural stability.

[0074] Thermal conductivity: Example 4 (enhance thermal conductivity) reduces the thermal conductivity to 0.059 W / (m·K) by increasing expanded graphite and aluminum nitride, which is better than Example 1 (standard formula); Example 3 (reduce palm methyl ester) slightly reduces the thermal conductivity, but the phase change temperature regulation is more accurate; The absence of key ingredients in Comparative Examples 1-4 generally increases the thermal conductivity to 0.08-0.09 W / (m·K), indicating that the synergistic effect of phase change materials and thermal conductive fillers cannot be replaced.

[0075] Water absorption capacity: Example 6 (optimize mechanical strength) reduces the water absorption rate to 7.5% and the shrinkage rate to 0.20% by filling the pores with nano-aluminum oxide, which is significantly better than the comparative example; Example 3 (reduce palm methyl ester) reduces the water absorption rate to 7.8% by reducing porosity, and the shrinkage rate is better.

[0076] Combustion performance: All samples meet the requirements of A-class non-combustible materials, but Example 5 (optimize fireproof performance) further improves high-temperature stability through the synergistic effect of propyl gallate and zinc borate.

[0077] Phase change energy storage efficiency: Example 2 (increase paraffin content) increases the proportion of phase change materials to 165 J / g, which is better than the standard formula of 158 J / g; The absence of key phase change materials in Comparative Examples 1-4 generally results in an energy storage efficiency of less than 140 J / g, indicating that the compounding of paraffin and palm methyl ester is the core of energy storage performance.

[0078] Through the above integrated experimental data, the comprehensive optimization of the phase change energy storage insulation mortar in compressive strength, thermal regulation, durability, fire resistance and energy storage efficiency is realized. The material can be widely used in residential energy-saving wall, sunlight greenhouse, public building outer wall and roof, etc. In the future, the technology can be combined with intelligent temperature control system to promote building energy saving from passive insulation to active temperature regulation, which is in line with the development trend of green building materials.

[0079] While the preferred embodiments of the application have been described, additional modifications and changes can occur to those skilled in the art once they learn of the basic creative principles disclosed herein. Accordingly, it is intended that the description be construed as illustrative only and not in a limiting sense. It is therefore desired that the appended claims be construed broadly to include all equivalents falling within the scope of the application.

[0080] Obviously, various modifications and changes can be made to the present application by those skilled in the art without departing from the spirit and scope of the application. Accordingly, it is intended that the present application embrace all such modifications and changes as fall within the scope of the appended claims and their equivalents.

Claims

1. A phase change energy storage thermal insulation mortar and a preparation method thereof, characterized in that: The composition is as follows in parts by mass: Paraffin: 80-120 parts; Methyl palmitate: 25-40 parts; Hydrophobic perlite: 120-180 parts; Expanded graphite: 8-15 parts; Phosphorus flake aluminum nitride: 3-6 parts; Sulphoaluminate cement: 180-250 parts; Volcanic rock powder: 60-100 parts; Hydroxypropyl methylcellulose: 0.3-0.8 parts; Polycarboxylate water reducer: 0.6-1.2 parts; Nano-alumina: 2-4 parts; Propyl gallate: 0.8-1.5 parts; Zinc borate: 1 to 2 parts.

2. The phase change energy storage thermal insulation mortar according to claim 1, characterized in that: The methyl palmitate is a transparent solution formed by esterification of palmitic acid and methanol; the hydrophobic perlite is a light yellow powder formed by soaking and modifying perlite in a silane coupling agent with a concentration of 0.5-1.0 wt%, and then drying; Wherein, the molar ratio of the palmitic acid to the methanol is 1:1.2-1:1.5; The mass ratio of the perlite to the silane coupling agent is 100:0.5-100:

1.

3. The phase change energy storage thermal insulation mortar according to claim 1, characterized in that: The expanded graphite is a black porous particle made by mixing natural graphite and an intercalant; the sulphoaluminate cement is a gray powder made by mixing sulphoaluminate clinker and gypsum; the volcanic rock powder is an off-white powder made by calcining volcanic rock at a high temperature of 800-900°C; The mass ratio of the natural graphite to the intercalant is 100:5-100:8, and the intercalant is a complex solution formed by mixing potassium bisulfate and hydrogen peroxide in a mass ratio of 1:2-1:3; The mass ratio of the sulphoaluminate clinker to the gypsum is 95:5-100:5.

5.

4. The phase change energy storage thermal insulation mortar according to claim 1, characterized in that: The polycarboxylate water reducer is a polymer water-reducing solution copolymerized with acrylic acid, maleic anhydride, and polyoxyethylene ether monomers; the propyl gallate is a white crystalline powder esterified with gallic acid and propanol; and the zinc borate is a hexagonal powder formed by mixing zinc oxide and boric acid at a high temperature of 800-900°C. Wherein, the molar ratio of the acrylic acid, the maleic anhydride and the polyoxyethylene ether monomer is 2:1:1-3:1:1; The molar ratio of the gallic acid to the propanol is 1:1.5-1:2; The mass ratio of the zinc oxide to the boric acid is 1:1-1:1.

2.

5. A method for preparing the phase-change energy storage thermal insulation mortar according to any one of claims 1 to 4, characterized in that: The steps include: After melting and blending the paraffin wax and the methyl palmitate, the expanded graphite and the phosphorus flake aluminum nitride are added to prepare a phase change energy storage composite; dry-mixing the hydrophobic perlite and the nano-alumina, and then preparing a lightweight composite aggregate through a high-pressure molding process; Mixing the sulphoaluminate cement, the volcanic rock powder, the hydroxypropyl methylcellulose and the polycarboxylate water reducer to prepare a gel slurry; Mixing the propyl gallate and the zinc borate to prepare antioxidant flame retardant microcapsules; The phase-change energy storage composite, the lightweight composite aggregate, the gelling slurry and the antioxidant flame-retardant microcapsules are mixed and poured into a mold to prepare the phase-change energy storage thermal insulation mortar.

6. The preparation method according to claim 5, characterized in that: The preparation of the phase change energy storage composite by melting and blending the paraffin wax and the methyl palmitate and then adding the expanded graphite and the phosphorus flake aluminum nitride comprises: The paraffin wax and the methyl palmitate are added into a melting kettle at a mass ratio of 3:1-4:1, heated to 80-90° C., stirred at a speed of 300-500 rpm, and stirred for 1-2 hours to obtain a molten blend; Adding the expanded graphite and the phosphorus flake aluminum nitride to the molten blend, and assisting dispersion for 10-20 minutes under an ultrasonic power of 300-500 W to prepare the phase change energy storage composite; The mass ratio of the molten blend, the expanded graphite and the phosphorus flake aluminum nitride is 100:8:3-100:15:

6.

7. The preparation method according to claim 5, characterized in that: The step of dry-mixing the hydrophobic perlite and the nano-alumina and then preparing the lightweight composite aggregate through a high-pressure molding process comprises: The hydrophobic perlite and the nano-alumina are added into a high-speed mixer at a mass ratio of 10:1-10:3, and mixed at a speed of 80-100 rpm for 5-10 minutes to obtain a mixture; The mixture is placed in a vacuum impregnation tank, evacuated to a pressure of -0.09 to -0.10 MPa, injected with deionized water until saturated, and then adjusted to a pressure of 10-12 MPa. After pressing for 30-35 seconds, the mixture is dried to prepare the lightweight composite aggregate.

8. The preparation method according to claim 5, characterized in that: The step of mixing the sulphoaluminate cement, the volcanic rock powder, the hydroxypropyl methylcellulose and the polycarboxylate water reducer to prepare the gelled slurry comprises: The sulphoaluminate cement and the volcanic rock powder are added into a planetary mixer at a mass ratio of 3:1-4:1, and mixed at a speed of 20-30 rpm for 10-15 minutes to obtain a base mixture; The basic mixture, the hydroxypropyl methylcellulose, the polycarboxylate water-reducing agent and deionized water are mixed in a mass ratio of 98:0.3:0.6:30-99:0.8:1.2:35, and stirred at a rotation speed of 120-150 rpm for 10-15 minutes to prepare the gel slurry.

9. The preparation method according to claim 5, characterized in that: The method of mixing the propyl gallate with the zinc borate to prepare the antioxidant flame retardant microcapsules comprises: The propyl gallate and the zinc borate were placed into a high-speed shearing machine at a mass ratio of 1:1.5-1:2, and sheared at a speed of 8000-10000 rpm for 10-20 minutes to obtain a mixed solution; The mixed liquid is spray-dried, and the air inlet temperature is controlled to be 180-200° C., the air outlet temperature is controlled to be 80-90° C., and the atomization pressure is controlled to be 0.4-0.6 MPa to prepare the antioxidant flame-retardant microcapsules.

10. The preparation method according to claim 5, characterized in that: The preparation of the phase change energy storage thermal insulation mortar by mixing the phase change energy storage composite, the lightweight composite aggregate, the gelling slurry and the antioxidant flame retardant microcapsules and pouring the mixture into a mold comprises: The phase change energy storage composite and the lightweight composite aggregate are sequentially added into a forced mixer in a mass ratio of 60:20-65:18, and mixed for 5-10 minutes at a stirring speed of 20-30 rpm to obtain an initial mixture; The initial mixture, the gel slurry and the antioxidant flame retardant microcapsules are mixed in a mass ratio of 70:15:10-78:13:9, and stirred at a speed of 80-100 rpm for 3-5 minutes to prepare a mixed slurry; The mixed slurry is poured into a mold, cured at a temperature of 20-25° C. for 28-30 days, and demolded to obtain the phase change energy storage thermal insulation mortar.

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