Phase change thermal insulation mortar and preparation method thereof

Abstract

The invention relates to the technical field of phase-change thermal insulation mortar, in particular to phase-change thermal insulation mortar and a preparation method thereof. The phase change thermal insulation mortar is prepared from the following raw materials in parts by mass: 100 to 120 parts of cement, 25 to 40 parts of fly ash, 1 to 2 parts of cellulose, 25 to 40 parts of machine-made sand, 30 to 60 parts of silicon dioxide microspheres, 5 to 15 parts of porous mineral, 30 to 60 parts of organic phase change material, 10 to 30 parts of polyethylene glycol, 1 to 3 parts of borax, 1 to 2 parts of epoxy resin, 0.01 to 0.1 part of tetraphenyltin, 1 to 2 parts of water repellent and 60 to 90 parts of water. The phase-change material has excellent aging resistance and a wide temperature application range, the service life of the phase-change material can be greatly prolonged, meanwhile, the phase-change material can more quickly receive and release heat, meanwhile, the durability of the thermal insulation mortar can be enhanced, the phase-change material is effectively prevented from permeating and overflowing in a matrix, and the thermal insulation mortar has good thermal insulation performance. And the mortar layer has long-term heat-insulating and energy-saving effects.

Description

Technical Field

[0001] The present invention relates to the technical field of phase change thermal insulation mortar, and particularly relates to a phase change thermal insulation mortar and a preparation method thereof. Background Art

[0002] With the development of the times and the increasing number of buildings, the importance of building energy conservation is also increasing. Thermal insulation mortar is a building energy conservation material that is currently widely used. However, thermal insulation mortar only has the function of heat insulation and does not have the function of energy storage, and cannot provide a more constant temperature for buildings.

[0003] Phase change temperature-regulating building materials are a new type of building material that uses phase change materials to absorb solar energy to regulate room temperature. Phase change temperature-regulating mortar is a new type of environmentally friendly and energy-saving mortar with a temperature-regulating function manufactured by utilizing the characteristics of phase change materials and mortar. Phase change materials undergo phase changes at their transformation temperatures. When the temperature is higher than the phase change temperature, they can absorb the heat of the environment, and when the temperature is lower than the transformation temperature, they release heat outward. The latent heat of phase change of phase change materials is used to achieve energy storage and utilization, which helps to improve energy efficiency and develop renewable energy.

[0004] At present, there are various phase change thermal insulation mortar products on the market, which are generally prepared by directly adding phase change materials to mortar. However, there is leakage of phase change materials. Although some are first compounded with inorganic porous materials and phase change materials and then added to mortar, the problem of external leakage of phase change materials still cannot be effectively solved. At the same time, compared with concrete, the water-cement ratio of thermal insulation mortar materials is larger, so its strength is lower than that of concrete, and it is more likely to produce cracks and water seepage during construction, seriously affecting the various performances and service life of thermal insulation mortar. Summary of the Invention

[0005] The purpose of the present invention is to solve the deficiencies in the prior art, and to provide a phase change thermal insulation mortar and a preparation method thereof.

[0006] A phase change thermal insulation mortar, the raw materials of which by mass include: 100-120 parts of cement, 25-40 parts of fly ash, 1-2 parts of cellulose, 25-40 parts of manufactured sand, 30-60 parts of silica microspheres, 5-15 parts of porous minerals, 30-60 parts of organic phase change materials, 10-30 parts of polyethylene glycol, 1-3 parts of borax, 1-2 parts of epoxy resin, 0.01-0.1 part of tetraphenyltin, 1-2 parts of water repellent, and 60-90 parts of water.

[0007] Preferably, the cement is P.O.42.5 Portland cement or / and P.O.52.5 Portland cement.

[0008] Preferably, the grade of fly ash is grade II.

[0009] Preferably, the fineness modulus of the manufactured sand is 2.0-2.5.

[0010] Preferably, the porous mineral includes at least one of expanded perlite, sepiolite, and zeolite.

[0011] Preferably, the organic phase change material is solid paraffin or / and octadecane.

[0012] Preferably, the silica microspheres are prepared by the following steps: adding cholesterol, lecithin, and tetraethyl orthosilicate into chloroform, ultrasonically treating for 5 - 15 min, rotary evaporating to remove chloroform, adding the mixture into an ethanol aqueous solution, dropwise adding an ammonia aqueous solution and continuing to ultrasonically treat for 10 - 20 min, standing for 1 - 2 h, filtering, washing, drying under vacuum, calcining at 400 - 500 °C for 1 - 2 h, and cooling to room temperature.

[0013] In the present invention, lecithin and cholesterol are compounded, and hydrophobic tetraethyl orthosilicate is confined therein. After hydrolysis, a silica spherical structure is formed, and the liposomes are removed by calcination, so that the obtained silica microspheres not only have a good coating effect on the liquid organic phase change material, but also have regular structure and extremely high stability.

[0014] More preferably, the mass ratio of cholesterol, lecithin, and tetraethyl orthosilicate is 1 - 5:10 - 20:1 - 3.

[0015] More preferably, the ultrasonic frequency is 20 - 40 kHz.

[0016] More preferably, the mass fraction of the ethanol aqueous solution is 50 - 80%, and the mass fraction of the ammonia aqueous solution is 20 - 30%.

[0017] The preparation method of the above phase change heat - insulating mortar includes the following steps:

[0018] S1. Mix the silica microspheres and the porous mineral evenly, add them into a vacuum reactor, heat to 70 - 80 °C, evacuate to a negative pressure of 40 - 80 kPa, close the air extraction valve, dropwise add the organic phase change material while stirring, after dropping, open the air extraction valve, evacuate the negative pressure of the vacuum reactor to 30 - 60 kPa, continue to stir for 1 - 2 h, restore to normal pressure and then unload, freeze, and crush to obtain the phase change material - loaded product;

[0019] S2. Melt polyethylene glycol under vacuum conditions, add the phase change material - loaded product, borax, epoxy resin, and tetraphenyltin, stir at 40 - 50 °C for 1 - 2 h, cool to room temperature, and add a water - repellent agent and mix evenly to obtain a premix;

[0020] S3. Add cement, fly ash, manufactured sand, and cellulose to the premix and mix evenly, and then add water and stir evenly.

[0021] Beneficial effects:

[0022] The present invention utilizes the complexation of silica microspheres and porous minerals to adsorb organic phase change materials, resulting in a very high adsorption capacity of the obtained phase change material-loaded product, but with poor stability. Further, in combination with polyethylene glycol, it is coated and cured on the surface of the phase change material-loaded product, which can effectively encapsulate the phase change material. It not only has excellent sealing performance, enhancing the anti-leakage property of the phase change material, but also has good thermal stability and good compatibility with the mortar matrix, effectively improving the thermal insulation performance of the mortar.

[0023] The present invention uses the combination of a phase change material-loaded product and polyethylene glycol, and is cured with borax and epoxy resin, which can reduce the surface tension in the thermal insulation mortar, enhance the uniformity and fluidity of the thermal insulation mortar, improve the stress and shrinkage deformation inside the concrete, and enhance the mechanical strength of the mortar layer. It not only enhances the crack resistance and anti-seepage performance of the mortar, but also is beneficial to improving the thermal insulation and energy-saving effect.

[0024] The present invention largely realizes the isolation between the phase change material and the mortar, maintains the heat storage / release performance of the phase change material, enables the phase change material to fully exert its heat storage / release performance during the phase change process; at the same time, it effectively avoids the leakage and migration of the phase change material during the mixing process with the mortar, enabling the phase change material to be stably applied in the thermal insulation mortar. By utilizing the fact that during the phase change process of the phase change material, it can absorb heat from the environment or release energy to the environment in the form of energy storage and release, the intelligent temperature regulation and energy-saving effect of the wall is achieved.

[0025] The present invention has excellent aging resistance and a wide temperature range of use, which can greatly enhance the service life of the phase change material. At the same time, it can make the phase change material receive and release heat faster, and can also enhance the durability of the thermal insulation mortar, effectively avoiding the overflow of the phase change material in the matrix, and enabling the mortar layer to have a long-term thermal insulation and energy-saving effect.

[0026] The method of the present invention is simple to operate, and the obtained phase change thermal insulation mortar has good thermal stability and crack resistance, and can effectively improve the thermal insulation performance of the mortar. Description of the Drawings

[0027] Figure 1 It is a comparison chart of the compressive strength and thermal conductivity of the phase change thermal insulation mortar obtained in Example 5 and Comparative Examples 1-2.

[0028] Figure 2 It is a comparison chart of the tensile bond strength and compressive shear bond strength of the phase change thermal insulation mortar obtained in Example 5 and Comparative Examples 1-2.

[0029] Figure 3 It is a comparison chart of the average value t of the time required to heat the phase change thermal insulation mortar obtained in Example 5 and Comparative Examples 1-2 to 40 °C after being applied to a wooden board and the maximum difference T.

[0030] Figure 4Comparison chart of the mass change rate of the phase change thermal insulation mortar obtained in Example 5 and Comparative Examples 1-2 after ultraviolet aging. Detailed implementation manners

[0031] The present invention will be further illustrated below with reference to specific embodiments.

[0032] The following manufactured sand is purchased from LingShou NingBo Mineral Products Co., Ltd., and the fineness modulus of the manufactured sand is 2.2. The following water repellent is purchased from a certain JingQingHai Trading Co., Ltd., and the specific model is: Wacker silicone waterproof agent BS1802.

[0033] Example 1

[0034] A phase change thermal insulation mortar, the raw materials thereof include: 1000 g of P.O.42.5 portland cement, 250 g of Class II fly ash, 10 g of cellulose, 250 g of manufactured sand, 300 g of silica microspheres, 50 g of expanded perlite, 300 g of solid paraffin, 100 g of polyethylene glycol 1500, 10 g of borax, 10 g of epoxy resin, 0.1 g of tetraphenyltin, 10 g of water repellent, and 600 g of water.

[0035] The silica microspheres are prepared by the following steps: adding 100 g of cholesterol, 1000 g of lecithin, and 100 g of tetraethyl orthosilicate into 1000 g of chloroform, ultrasonically treating for 5 min, the ultrasonic frequency is 20 kHz, rotary evaporating to remove chloroform, adding into 5000 g of an ethanol aqueous solution with a mass fraction of 50%, dropping 100 g of an ammonia aqueous solution with a mass fraction of 20% and continuing to ultrasonically treat for 10 min, standing for 1 h, filtering, washing, vacuum drying, feeding into a muffle furnace and calcining at a temperature of 400 °C for 1 h, and cooling to room temperature.

[0036] The preparation method of the above phase change thermal insulation mortar includes the following steps:

[0037] S1. Mix the silica microspheres and expanded perlite evenly, add them into a vacuum reactor, heat to 70 °C, evacuate to a negative pressure of 40 kPa, close the air extraction valve, dropwise add solid paraffin while stirring, after dropping, open the air extraction valve, evacuate the negative pressure of the vacuum reactor to 30 kPa, continue stirring for 1 h, restore to normal pressure and then unload, freeze, and crush to obtain a phase change material-loaded product;

[0038] S2. Melt polyethylene glycol 1500 under vacuum conditions, add the phase change material-loaded product, borax, epoxy resin, and tetraphenyltin, stir at a temperature of 40 °C for 1 h, cool to room temperature, and add the water repellent and mix evenly to obtain a premix;

[0039] S3. Add P.O.42.5 portland cement, fly ash, manufactured sand, and cellulose to the premix and mix evenly, and add water and stir evenly.

[0040] Example 2

[0041] A phase change heat preservation mortar, the raw materials of which include: 1200 g of P.O.42.5 portland cement, 400 g of Class II fly ash, 20 g of cellulose, 400 g of manufactured sand, 600 g of silica microspheres, 100 g of expanded perlite, 50 g of sepiolite, 600 g of solid paraffin, 300 g of polyethylene glycol 1500, 30 g of borax, 20 g of epoxy resin, 1 g of tetraphenyltin, 20 g of water repellent, and 900 g of water.

[0042] The silica microspheres are prepared by the following steps: adding 100 g of cholesterol, 400 g of lecithin, and 60 g of tetraethyl orthosilicate into 400 g of chloroform, performing ultrasonic treatment for 15 min with an ultrasonic frequency of 40 kHz, removing chloroform by rotary evaporation, adding the mixture into 2000 g of an ethanol aqueous solution with a mass fraction of 80%, dropping 60 g of an ammonia aqueous solution with a mass fraction of 30%, continuing ultrasonic treatment for 20 min, standing for 2 h, filtering, washing, drying under vacuum, feeding into a muffle furnace, calcining at a temperature of 500 °C for 2 h, and cooling to room temperature.

[0043] The preparation method of the above phase change heat preservation mortar includes the following steps:

[0044] S1. Mix the silica microspheres, expanded perlite, and sepiolite evenly, add them into a vacuum reactor, heat to 80 °C, evacuate to a negative pressure of 80 kPa, close the air extraction valve, dropwise add solid paraffin while stirring, after dropping is completed, open the air extraction valve, evacuate the negative pressure of the vacuum reactor to 60 kPa, continue stirring for 2 h, restore to normal pressure, unload, freeze, and crush to obtain a phase change material-loaded product;

[0045] S2. Melt polyethylene glycol 1500 under vacuum conditions, add the phase change material-loaded product, borax, epoxy resin, and tetraphenyltin, stir at a temperature of 50 °C for 2 h, cool to room temperature, and add a water repellent and mix evenly to obtain a premix;

[0046] S3. Add P.O.52.5 portland cement, fly ash, manufactured sand, and cellulose to the premix and mix evenly, then add water and stir evenly.

[0047] Example 3

[0048] A phase change heat preservation mortar, the raw materials of which include: 1050 g of P.O.52.5 portland cement, 350 g of Class II fly ash, 13 g of cellulose, 360 g of manufactured sand, 400 g of silica microspheres, 120 g of zeolite, 400 g of octadecane, 250 g of polyethylene glycol 1500, 15 g of borax, 18 g of epoxy resin, 0.3 g of tetraphenyltin, 17 g of water repellent, and 700 g of water.

[0049] The silicon dioxide microspheres are prepared by the following steps: Add 120 g of cholesterol, 360 g of lecithin, and 75 g of tetraethyl orthosilicate to 360 g of chloroform, and perform ultrasonic treatment for 12 min at an ultrasonic frequency of 24 kHz. Rotary evaporate to remove chloroform, add it to 2700 g of an ethanol aqueous solution with a mass fraction of 60%, dropwise add 75 g of an ammonia aqueous solution with a mass fraction of 22%, continue ultrasonic treatment for 18 min, let it stand for 80 min, filter, wash, vacuum dry, send it into a muffle furnace, calcine at a temperature of 480 °C for 80 min, and cool to room temperature.

[0050] The preparation method of the above phase change heat preservation mortar includes the following steps:

[0051] S1. Mix the silicon dioxide microspheres and zeolite evenly, add them to a vacuum reactor, heat to 77 °C, evacuate to a negative pressure of 50 kPa, close the air extraction valve, dropwise add octadecane while stirring. After the addition is completed, open the air extraction valve, evacuate the negative pressure of the vacuum reactor to 40 kPa, continue stirring for 80 min, restore to normal pressure, unload, freeze, and crush to obtain the phase change material-loaded product;

[0052] S2. Melt polyethylene glycol 1500 under vacuum conditions, add the phase change material-loaded product, borax, epoxy resin, and tetraphenyltin, stir at a temperature of 48 °C for 80 min, cool to room temperature, and add a water repellent and mix evenly to obtain a premix;

[0053] S3. Add P.O.52.5 portland cement, fly ash, manufactured sand, and cellulose to the premix and mix evenly, then add water and stir evenly.

[0054] Example 4

[0055] A phase change heat preservation mortar, the raw materials of which include: 1150 g of P.O.52.5 portland cement, 300 g of Class II fly ash, 17 g of cellulose, 300 g of manufactured sand, 500 g of silicon dioxide microspheres, 40 g of sepiolite, 40 g of zeolite, 500 g of octadecane, 150 g of polyethylene glycol 1500, 25 g of borax, 12 g of epoxy resin, 0.7 g of tetraphenyltin, 13 g of water repellent, and 800 g of water.

[0056] The silicon dioxide microspheres are prepared by the following steps: Add 60 g of cholesterol, 540 g of lecithin, and 45 g of tetraethyl orthosilicate to 540 g of chloroform, and perform ultrasonic treatment for 8 min at an ultrasonic frequency of 36 kHz. Rotary evaporate to remove chloroform, add it to 2100 g of an ethanol aqueous solution with a mass fraction of 70%, dropwise add 45 g of an ammonia aqueous solution with a mass fraction of 28%, continue ultrasonic treatment for 12 min, let it stand for 100 min, filter, wash, vacuum dry, send it into a muffle furnace, calcine at a temperature of 420 °C for 100 min, and cool to room temperature.

[0057] The preparation method of the above-mentioned phase change heat-insulating mortar comprises the following steps:

[0058] S1. Mix silica microspheres, sepiolite, and zeolite evenly, add them to a vacuum reactor, heat to 73 °C, evacuate to a negative pressure of 70 kPa, close the air extraction valve, dropwise add octadecane while stirring. After the addition is complete, open the air extraction valve, evacuate the negative pressure of the vacuum reactor to 50 kPa, continue stirring for 100 min, restore to normal pressure, unload, freeze, and crush to obtain the phase change material-loaded product;

[0059] S2. Melt polyethylene glycol 1500 under vacuum conditions, add the phase change material-loaded product, borax, epoxy resin, and tetraphenyltin, stir at 42 °C for 100 min, cool to room temperature, and add a water repellent and mix evenly to obtain a premix;

[0060] S3. Add P.O.52.5 portland cement, fly ash, manufactured sand, and cellulose to the premix and mix evenly, then add water and stir evenly.

[0061] Example 5

[0062] A kind of phase change heat-insulating mortar, whose raw materials include: 1100 g of P.O.42.5 portland cement, 320 g of class II fly ash, 15 g of cellulose, 330 g of manufactured sand, 450 g of silica microspheres, 60 g of expanded perlite, 40 g of zeolite, 450 g of octadecane, 200 g of polyethylene glycol 1500, 20 g of borax, 15 g of epoxy resin, 0.5 g of tetraphenyltin, 15 g of water repellent, and 750 g of water.

[0063] The silica microspheres are prepared by the following steps: Add 75 g of cholesterol, 375 g of lecithin, and 50 g of tetraethyl orthosilicate to 375 g of chloroform, perform ultrasonic treatment for 10 min, the ultrasonic frequency is 30 kHz, rotary evaporate to remove chloroform, add it to 2000 g of an ethanol aqueous solution with a mass fraction of 65%, dropwise add 50 g of an ammonia aqueous solution with a mass fraction of 25%, continue ultrasonic treatment for 15 min, let stand for 90 min, filter, wash, dry under vacuum, send it into a muffle furnace, calcine at 450 °C for 90 min, and cool to room temperature.

[0064] The preparation method of the above-mentioned phase change heat-insulating mortar comprises the following steps:

[0065] S1. Mix silica microspheres, expanded perlite, and zeolite evenly, add them to a vacuum reactor, heat to 75 °C, evacuate to a negative pressure of 60 kPa, close the air extraction valve, dropwise add octadecane while stirring. After the addition is complete, open the air extraction valve, evacuate the negative pressure of the vacuum reactor to 45 kPa, continue stirring for 90 min, restore to normal pressure, unload, freeze, and crush to obtain the phase change material-loaded product;

[0066] S2. Melt polyethylene glycol 1500 under vacuum conditions, add the loaded phase change material, borax, epoxy resin, and tetraphenyltin, stir at 45°C for 90 min, cool to room temperature, add a water repellent and mix evenly to obtain a premix;

[0067] S3. Add P.O.42.5 portland cement, fly ash, manufactured sand, and cellulose to the premix and mix evenly, then add water and stir evenly.

[0068] Comparative Example 1

[0069] A phase change heat-insulating mortar, the raw materials of which include: 1100 g of P.O.42.5 portland cement, 320 g of Class II fly ash, 15 g of cellulose, 330 g of manufactured sand, 450 g of mesoporous silica, 60 g of expanded perlite, 40 g of zeolite, 450 g of octadecane, 200 g of polyethylene glycol 1500, 20 g of borax, 15 g of epoxy resin, 0.5 g of tetraphenyltin, 15 g of water repellent, and 750 g of water.

[0070] The preparation method of the above phase change heat-insulating mortar includes the following steps:

[0071] S1. Mix mesoporous silica, expanded perlite, and zeolite evenly, add them to a vacuum reactor, heat to 75°C, evacuate to a negative pressure of 60 kPa, close the air extraction valve, dropwise add octadecane while stirring, after dropping, open the air extraction valve, evacuate the negative pressure of the vacuum reactor to 45 kPa, continue stirring for 90 min, restore to normal pressure and then unload, freeze, and crush to obtain the loaded phase change material;

[0072] S2. Melt polyethylene glycol 1500 under vacuum conditions, add the loaded phase change material, borax, epoxy resin, and tetraphenyltin, stir at 45°C for 90 min, cool to room temperature, add a water repellent and mix evenly to obtain a premix;

[0073] S3. Add P.O.42.5 portland cement, fly ash, manufactured sand, and cellulose to the premix and mix evenly, then add water and stir evenly.

[0074] Comparative Example 2

[0075] A phase change heat-insulating mortar, the raw materials of which include: 1100 g of P.O.42.5 portland cement, 320 g of Class II fly ash, 15 g of cellulose, 330 g of manufactured sand, 450 g of silica microspheres, 60 g of expanded perlite, 40 g of zeolite, 450 g of octadecane, 235 g of polyethylene glycol 1500, 0.5 g of tetraphenyltin, 15 g of water repellent, and 750 g of water.

[0076] Silica microspheres are prepared by the following steps: Add 75 g of cholesterol, 375 g of lecithin, and 50 g of tetraethyl orthosilicate to 375 g of chloroform and ultrasonically treat for 10 min at an ultrasonic frequency of 30 kHz. Rotary evaporate to remove chloroform, add it to 2000 g of an ethanol aqueous solution with a mass fraction of 65%, dropwise add 50 g of an ammonia aqueous solution with a mass fraction of 25%, continue ultrasonic treatment for 15 min, let stand for 90 min, filter, wash, vacuum dry, send it into a muffle furnace, calcine at a temperature of 450 °C for 90 min, and cool to room temperature.

[0077] The preparation method of the above-mentioned phase change thermal insulation mortar includes the following steps:

[0078] S1. Mix silica microspheres, expanded perlite, and zeolite evenly, add them to a vacuum reactor, heat to 75 °C, evacuate to a negative pressure of 60 kPa, close the air extraction valve, dropwise add octadecane while stirring, after dropping is completed, open the air extraction valve, evacuate the negative pressure of the vacuum reactor to 45 kPa, continue stirring for 90 min, restore to normal pressure and then unload, freeze, and crush to obtain the phase change material-loaded product;

[0079] S2. Melt polyethylene glycol 1500 under vacuum conditions, add the phase change material-loaded product and tetraphenyltin, stir at a temperature of 45 °C for 90 min, cool to room temperature, and add a water repellent and mix evenly to obtain a premix;

[0080] S3. Add P.O.42.5 portland cement, fly ash, manufactured sand, and cellulose to the premix and mix evenly, and add water and stir evenly.

[0081] Refer to GB / T 20473-2021 "Building Thermal Insulation Mortar" to measure the compressive strength, thermal conductivity, tensile bond strength, and compression-shear bond strength of the phase change thermal insulation mortar obtained in Example 5 and Comparative Examples 1-2.

[0082] As Figure 1 and Figure 2 shown, the compressive strength, tensile bond strength, and compression-shear bond strength of the phase change thermal insulation mortar obtained in Example 5 are all the highest, while the thermal conductivity is the smallest, which is superior to Comparative Examples 1-2 (P < 0.05).

[0083] Apply the phase change thermal insulation mortar obtained in Example 5 and Comparative Examples 1-2 evenly on the surface of a 1 m × 1 m wooden board respectively. After the mortar is completely cured, face the side with the mortar towards the heating device, take four symmetric points on the other side of the wooden board and install temperature measuring instruments, and then heat the mortar at a temperature of 40 °C, measure the time required for the four points to be heated to 40 °C, and calculate the average value t of the time of the four points and the maximum difference T.

[0084] As Figure 3As shown, the time average value of the phase change thermal insulation mortar obtained in Example 5 is the largest, and the maximum time difference is the smallest, which is better than Comparative Examples 1-2 (P < 0.05). This confirms that the phase change thermal insulation mortar obtained by the present invention is uniform, and at the same time effectively avoids the leakage and migration of the phase change material during the mixing process with the mortar, enabling the stable application of the phase change material in the thermal insulation mortar. By utilizing the phase change material during the phase change process, heat can be absorbed from the environment or energy can be released to the environment in the form of energy storage and release.

[0085] After curing the phase change thermal insulation mortars obtained in Example 5 and Comparative Examples 1-2 according to the requirements in GB / T 20473-2021 "Building Thermal Insulation Mortar", they were placed in an ultraviolet aging chamber for treatment. The parameters of the ultraviolet aging chamber were set as follows: the temperature was 50 °C, the ultraviolet wavelength was 340 nm, the light intensity was 0.76 W / (m 2 ·nm), the exposure cycle was 5 h of drying and 1 h of spraying, the cycle period was 15 cycles. After the cycle period ended, the samples were taken out, and the mass change rate was calculated to characterize the anti-leakage performance.

[0086] Mass change rate = (initial mass of the specimen - mass of the specimen after ultraviolet aging) ÷ mass of the specimen after ultraviolet aging × 100%

[0087] As Figure 4 shown, the mass change rate of the phase change thermal insulation mortar obtained in Example 5 is the smallest, which is better than Comparative Examples 1-2 (P < 0.05).

[0088] The applicant believes that: This is because the present invention uses the compounding of silica microspheres and porous minerals to adsorb the organic phase change material, resulting in a very high adsorption capacity of the obtained loaded phase change material, but poor stability; further compounding with polyethylene glycol and coating and curing on the surface of the loaded phase change material can effectively encapsulate the phase change material, not only with excellent sealing performance, enhancing the anti-leakage property of the phase change material, but also with good thermal stability and good compatibility with the mortar matrix, effectively improving the thermal insulation performance of the mortar. At the same time, the present invention uses the combination of the loaded phase change material and polyethylene glycol, cured with borax and epoxy resin, which can reduce the surface tension in the thermal insulation mortar, enhance the uniformity and fluidity of the thermal insulation mortar, improve the internal stress and shrinkage deformation of the concrete, and enhance the mechanical strength of the mortar layer, not only enhancing the crack resistance and anti-seepage performance of the mortar, but also being beneficial to improving the thermal insulation and energy-saving effect.

[0089] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A phase change thermal insulation mortar, characterized in that: The raw materials include, by mass, 100-120 parts of cement, 25-40 parts of fly ash, 1-2 parts of cellulose, 25-40 parts of machine-made sand, 30-60 parts of silica microspheres, 5-15 parts of porous minerals, 30-60 parts of organic phase change materials, 10-30 parts of polyethylene glycol, 1-3 parts of borax, 1-2 parts of epoxy resin, 0.01-0.1 parts of tetraphenyltin, 1-2 parts of water repellent and 60-90 parts of water.

2. The phase change thermal insulation mortar according to claim 1, characterized in that: The cement is PO42.5 silicate cement and / or PO52.5 silicate cement.

3. The phase change thermal insulation mortar according to claim 1, characterized in that: The grade of fly ash is Class II.

4. The phase change thermal insulation mortar according to claim 1, characterized in that: The fineness modulus of artificial sand is 2.0-2.

5.

5. The phase change thermal insulation mortar according to claim 1, characterized in that: The porous mineral includes at least one of expanded perlite, sepiolite and zeolite.

6. The phase change thermal insulation mortar according to claim 1, characterized in that: The organic phase change material is solid paraffin and / or octadecane.

7. The phase change thermal insulation mortar according to claim 1, characterized in that: The silica microspheres are prepared by the following steps: cholesterol, lecithin and ethyl orthosilicate are added to chloroform and ultrasonically treated for 5-15 minutes, the chloroform is removed by rotary evaporation, the mixture is added to an ethanol aqueous solution, an ammonia aqueous solution is added dropwise, and the ultrasonic treatment is continued for 10-20 minutes, the mixture is allowed to stand for 1-2 hours, filtered, washed, vacuum dried, calcined at 400-500° C. for 1-2 hours, and cooled to room temperature.

8. The phase change thermal insulation mortar according to claim 7, characterized in that: The mass ratio of cholesterol, lecithin and tetraethyl orthosilicate is 1-5:10-20:1-3.

9. The phase change thermal insulation mortar according to claim 7, characterized in that: The ultrasound frequency is 20-40kHz.

10. A method for preparing the phase change thermal insulation mortar according to any one of claims 1 to 9, characterized in that: The steps include: S1. Mix the silica microspheres and porous minerals evenly, add them to a vacuum reactor, heat to 70-80°C, evacuate to a negative pressure of 40-80 kPa, close the exhaust valve, and dropwise add the organic phase change material while stirring. After the dropwise addition is completed, open the exhaust valve, pump the negative pressure of the vacuum reactor to 30-60 kPa, continue stirring for 1-2 hours, restore to normal pressure, unload, freeze, and crush to obtain the loaded phase change material; S2, melt polyethylene glycol under vacuum conditions, add loaded phase change material, borax, epoxy resin, tetraphenyltin, stir at 40-50° C. for 1-2 hours, cool to room temperature, add a water repellent and mix well to obtain a premix; S3. Add cement, fly ash, machine-made sand and cellulose to the premix and mix evenly, then add water and stir evenly.

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