SiO2 aerogel / magnesia-sulphur cement-based thermal insulation mortar and preparation method thereof

Abstract

This invention provides a SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar and its preparation method. The thermal insulation mortar material includes components A, B, C, and D. Component A includes 65 parts of lightly calcined magnesium oxide and 5-50 parts of silica aerogel. Component B includes 25-35 parts of magnesium sulfate heptahydrate, 0.1-1 parts of modifier, 0-3 parts of reinforcing agent, 26-32 parts of water, 0-3 parts of thickener, and 0-3 parts of water-repellent agent. Component C includes 60-650 parts of water and 1-15 parts of dispersant. Component D includes 0-20 parts of inert filler, 0-30 parts of pre-formed foam, and 0-5 parts of fiber. The large-volume aerogel in the SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar provided by this invention can be uniformly dispersed in the cement-based material without interfacial delamination, and has advantages such as high strength, lightweight, good thermal insulation performance, and high softening coefficient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, in particular to a SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar and a preparation method thereof. BACKGROUND

[0002] Magnesium oxysulfate cement is a new type of air-hardening cementing material, which is mainly made of light-burned magnesium oxide powder and magnesium sulfate solution. It has attracted widespread attention due to its low carbon emission, light weight, early strength, good adhesion, fireproof and thermal insulation performance. With the development of the times and the progress of technology, especially in recent years, higher requirements have been put forward for energy saving and consumption reduction in the construction industry. Among them, the thermal performance of building envelope (floor, roof and wall) is the main factor, because it greatly consumes the energy required to maintain indoor comfortable temperature. The use of thermal insulation materials in walls and roofs is one of the most effective ways to ensure energy saving, which can reduce heat loss. Even after 30 years of using thermal insulation materials in most countries, super thermal insulation materials are still the main materials for improving the energy efficiency of buildings. As a building energy-saving insulation material, magnesium oxysulfate cement usually appears in the form of foamed magnesium oxysulfate cement insulation board, but its high thermal conductivity and poor water resistance still cannot be widely used.

[0003] Aerogel refers to a kind of nanoscale porous solid material obtained by sol-gel method, gel preparation, aging, washing and drying processes. Currently, commercial aerogels are mostly made by hydrophobic modification and atmospheric pressure drying, which have better water resistance and lower thermal conductivity than aerogels obtained by supercritical CO2 drying technology. Commonly known aerogels are silica aerogels, which have more than 90% of the volume inside as air, high specific surface area (500-1200 m 2 / g), low density (30-300 kg / m 3 ) and low thermal conductivity (0.012-0.025 W / (m·k)). The thermal insulation performance of aerogel is better than that of common thermal insulation materials such as polystyrene (EPS) and foamed polyurethane (PU), and it has potential advantages as a non-combustible material for building energy saving.

[0004] However, there are few studies on the incorporation of aerogel into existing magnesium oxysulfate cement, and the aerogel has hydrophobicity, so the amount of aerogel incorporated into magnesium oxysulfate cement is small. SUMMARY

[0005] To solve the problems in the background art, the present application provides a SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar and a preparation method thereof, which further reduces the thermal conductivity of magnesium oxysulfate cement and improves its fireproof performance.

[0006] The technical solution of the present application to solve the above technical problems is as follows:

[0007] In a first aspect, the present application provides a SiO2 aerogel / magnesia-sulphur cement-based thermal insulation mortar, which comprises component A, component B, component C and component D, the component A comprises the following raw materials in parts by weight: 65 parts of light-burned magnesia, 5-50 parts of SiO2 aerogel; the component B comprises the following raw materials in parts by weight: 25-35 parts of magnesium sulfate heptahydrate, 0.1-1 parts of a modifier, 0-3 parts of a reinforcing agent, 26-32 parts of water, 0-3 parts of a thickening agent, 0-3 parts of a water-repellent agent; the component C comprises the following raw materials in parts by weight: 60-650 parts of water, 1-15 parts of a dispersing agent; the component D comprises the following raw materials in parts by weight: 0-20 parts of an inert filler, 0-30 parts of a preformed foam, 0-5 parts of a fiber.

[0008] Further, the dispersing agent is 10% to 60% of the mass of the SiO2 aerogel.

[0009] Further, the content of active magnesia in the light-burned magnesia is 50% to 70%. The SiO2 aerogel is a hydrophobic aerogel, the particle size is 10-100 μm, the porosity is 90% to 95%, and the thermal conductivity is 0.012-0.018 W / (m·K).

[0010] Further, the modifier is one or more of monohydrated citric acid, sodium citrate, trisodium phosphate, sodium tripolyphosphate, and tartaric acid, the reinforcing agent is one or both of sodium sulfate and potassium sulfate, and the thickening agent is one or more of hydroxypropyl methylcellulose, xanthan gum, soluble starch, and dextrin.

[0011] Further, the water-repellent agent is silicone water-repellent powder.

[0012] Further, the dispersing agent is one or more of dispersing surfactant FM600, thickening surfactant FM400, silane coupling agent KH550, BASF TO-10 isomeric tridecanol polyoxyethylene ether, sodium perfluoro-nonylene oxybenzenesulfonate, fatty alcohol polyoxyethylene ether, and sodium fatty alcohol polyoxyethylene ether sulfate.

[0013] Further, the inert filler is one or more of polystyrene particles, graphite polystyrene particles, and expanded cork particles, and the fiber is one or more of glass fiber, PP fiber, and wood fiber.

[0014] Further, the preformed foam is a water solution prepared by 0.1-3 wt% ST-YH-1 foaming agent, and is obtained by foaming.

[0015] In a second aspect, the present application provides a preparation method of the above-mentioned SiO2 aerogel / magnesia-sulphur cement-based thermal insulation mortar, which comprises the following steps:

[0016] S1. Weigh the raw materials according to the weight parts, mix the lightly calcined magnesium oxide and silica aerogel evenly to obtain component A, mix magnesium sulfate heptahydrate, modifier, reinforcing agent, hydrophobic agent, thickener and water evenly to obtain component B, mix the dispersant and water evenly to obtain component C;

[0017] S2. Add components B and C to component A in sequence, mix evenly and stir to obtain SiO2 aerogel / magnesium oxysulfate cementitious slurry;

[0018] S3. Add component D to the SiO2 aerogel / sulfur-oxygen magnesium cement-based slurry and stir evenly to obtain SiO2 aerogel / sulfur-oxygen magnesium cement-based thermal insulation mortar.

[0019] Thirdly, the present invention provides a SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation material, which is prepared by the following method: the SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar according to any one of claims 1-8 is poured into a mold, vibrated and leveled, and then cured according to standard conditions until demolding, and then cured to the specified age. The standard curing conditions are a temperature of 20℃-30℃, a relative humidity of 60%-70%, and a demolding time of 1-3 days.

[0020] The beneficial effects of this invention are as follows: This invention modifies the aerogel with a dispersant, giving it an "internal hydrophobic and external hydrophilic" characteristic. This not only ensures good compatibility between the aerogel and magnesium oxysulfate cement, but also preserves the nanoporous structure of the aerogel. Furthermore, it produces a lightweight, heat-insulating, and fire-resistant thermal insulation mortar, solving the problems of high thermal conductivity and poor water resistance associated with magnesium oxysulfate cement. Its thermal conductivity is 0.1–0.03 W / (m·K), and its density is less than 450 kg / m³. 3 It has a softening coefficient of 0.85 or higher and a combustion performance rating of Class A. Attached Figure Description

[0021] Figure 1 The images show the SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar prepared in Example 1 of this invention and its cured physical product. Figure 1 Image a shows a physical sample of SiO2 aerogel / magnesium oxysulfate cementitious slurry. Figure 1 b is a photograph of the SiO2 aerogel / magnesium oxysulfate cementitious grout after 1 day of curing. Figure 1 c is a photo of SiO2 aerogel / magnesium oxysulfate cementitious grout cured for 28 days.

[0022] Figure 2 The image shows a physical sample of SiO2 aerogel and magnesium oxysulfate cement used in Comparative Example 3 to investigate their compatibility. Detailed Implementation

[0023] The principles and features of the present invention are described below with reference to the accompanying drawings and specific embodiments. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0024] In the following examples, the silica aerogel used was AG-D nano silica aerogel powder from Shenzhen Zhongning Technology Co., Ltd.; the silicone hydrophobic powder used had a silicone content of 68%; the sodium perfluorononenoxybenzenesulfonate used was the OBS anionic surfactant from Wuhan Shuer Biotechnology Co., Ltd.; FM400 and FM600 used were surfactants from Qingdao Fumais Chemical Co., Ltd.; the isomeric tridecyl alcohol polyoxyethylene ether used was the TO-10 nonionic surfactant from BASF, Germany; and the foaming agent used was the ST-YH-1 foaming agent from Shanghai Shengtai Co., Ltd. The high-activity light-burned magnesium oxide used contained 67.3% active magnesium oxide, while the low-activity light-burned magnesium oxide used contained 54.8% active magnesium oxide.

[0025] Example 1

[0026] A SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar includes component A, component B and component C. Component A includes 65 parts of low-activity lightly calcined magnesium oxide and 10 parts of silica aerogel by mass ratio; component B includes 30 parts of magnesium sulfate heptahydrate, 0.2 parts of citric acid monohydrate, 0.2 parts of sodium citrate and 29 parts of water by mass ratio; component C includes 95 parts of water and 4 parts of TO-10 isomeric tridecyl alcohol polyoxyethylene ether by mass ratio.

[0027] The preparation method of the above-mentioned SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar includes the following steps:

[0028] 1) Mix low-activity lightly calcined magnesium oxide with silica aerogel to obtain component A;

[0029] 2) Mix magnesium sulfate heptahydrate, citric acid monohydrate, sodium citrate, and water evenly to obtain component B;

[0030] 3) Mix TO-10 isomeric tridecyl alcohol polyoxyethylene ether and water evenly to obtain component C;

[0031] 4) Add components B and C to component A in sequence, mix evenly and stir to obtain SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation slurry;

[0032] Thermal insulation materials were prepared using the above-mentioned SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar: The prepared SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar was poured into a mold, vibrated and leveled, and then cured for 3 days in an environment with a temperature of 25℃ and a relative humidity of 65%. After demolding, it was cured for 28 days in an environment with a temperature of 25℃ and a relative humidity of 65%.

[0033] Example 2

[0034] A SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar includes component A, component B, and component C. Component A, by mass ratio, includes 65 parts of highly active lightly calcined magnesium oxide and 16 parts of silica aerogel; component B, by mass ratio, includes 25 parts of magnesium sulfate heptahydrate, 0.4 parts of citric acid monohydrate, 0.2 parts of trisodium phosphate, and 26 parts of water; component C, by mass ratio, includes 180 parts of water, 4 parts of sodium perfluorononenoxybenzenesulfonate, 1 part of thickening surfactant FM400, and 1 part of dispersing surfactant FM600.

[0035] The preparation method of the above-mentioned SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar includes the following steps:

[0036] 1) Mix highly active lightly calcined magnesium oxide with silica aerogel to obtain component A;

[0037] 2) Mix magnesium sulfate heptahydrate, citric acid monohydrate, trisodium phosphate, and water thoroughly to obtain component B;

[0038] 3) Sodium perfluorononenoxybenzenesulfonate, thickening surfactant FM400, dispersing surfactant FM600, and water are mixed evenly to obtain component C;

[0039] 4) Add components B and C to component A in sequence, mix evenly and stir to obtain SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation slurry;

[0040] Thermal insulation materials were prepared using the above-mentioned SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar: The prepared SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar was poured into a mold, vibrated and leveled, and then cured for 3 days in an environment with a temperature of 25℃ and a relative humidity of 65%. After demolding, it was cured for 28 days in an environment with a temperature of 25℃ and a relative humidity of 65%.

[0041] Example 3

[0042] A SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar includes component A, component B, and component C. Component A, by mass ratio, includes 65 parts of highly active lightly calcined magnesium oxide and 25 parts of silica aerogel; component B, by mass ratio, includes 27 parts of magnesium sulfate heptahydrate, 0.5 parts of tartaric acid, 0.2 parts of citric acid, 1 part of sodium sulfate, 28 parts of water, 1 part of xanthan gum, and 0.1 parts of hydroxypropyl methylcellulose; component C, by mass ratio, includes 290 parts of water, 6 parts of TO-10 isotridecyl alcohol polyoxyethylene ether, and 2 parts of sodium perfluorononenoxybenzenesulfonate.

[0043] The preparation method of the above-mentioned SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar includes the following steps:

[0044] 1) Mix highly active lightly calcined magnesium oxide with silica aerogel to obtain component A;

[0045] 2) Mix magnesium sulfate heptahydrate, citric acid monohydrate, tartaric acid, sodium sulfate, xanthan gum, hydroxypropyl methylcellulose, and water evenly to obtain component B;

[0046] 3) Mix TO-10 isomeric tridecyl alcohol polyoxyethylene ether, sodium perfluorononenoxybenzenesulfonate, and water evenly to obtain component C.

[0047] 4) Add components B and C to component A in sequence, mix evenly and stir to obtain SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation slurry;

[0048] Thermal insulation materials were prepared using the above-mentioned SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar: The prepared SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar was poured into a mold, vibrated and leveled, and then cured for 3 days in an environment with a temperature of 25℃ and a relative humidity of 65%. After demolding, it was cured for 28 days in an environment with a temperature of 25℃ and a relative humidity of 65%.

[0049] Example 4

[0050] A SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar includes component A, component B, and component C. Component A, by mass ratio, includes 65 parts of highly active lightly calcined magnesium oxide and 35 parts of silica aerogel. Component B, by mass ratio, includes 27 parts of magnesium sulfate heptahydrate, 0.3 parts of citric acid monohydrate, 0.2 parts of sodium tripolyphosphate, 0.1 parts of trisodium phosphate, 1 part of sodium sulfate, 0.5 parts of potassium sulfate, 30 parts of water, 1 part of soluble starch, and 1 part of xanthan gum. Component C, by mass ratio, includes 400 parts of water, 3 parts of sodium perfluorononenoxybenzenesulfonate, 2 parts of sodium fatty alcohol polyoxyethylene ether sulfate, and 2 parts of fatty alcohol polyoxyethylene ether.

[0051] The preparation method of the above-mentioned SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar includes the following steps:

[0052] 1) Mix highly active lightly calcined magnesium oxide with silica aerogel to obtain component A;

[0053] 2) Mix magnesium sulfate heptahydrate, citric acid monohydrate, sodium tripolyphosphate, trisodium phosphate, sodium sulfate, potassium sulfate, xanthan gum, soluble starch, and water evenly to obtain component B;

[0054] 3) Sodium perfluorononenoxybenzenesulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, fatty alcohol polyoxyethylene ether, and water are mixed evenly to obtain component C.

[0055] 4) Add components B and C to component A in sequence, mix evenly and stir to obtain SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation slurry;

[0056] Thermal insulation materials were prepared using the above-mentioned SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar: The prepared SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar was poured into a mold, vibrated and leveled, and then cured for 3 days in an environment with a temperature of 25℃ and a relative humidity of 65%. After demolding, it was cured for 28 days in an environment with a temperature of 25℃ and a relative humidity of 65%.

[0057] Example 5

[0058] A SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar includes component A, component B, and component C. Component A, by mass ratio, includes 65 parts of highly active lightly calcined magnesium oxide and 45 parts of silica aerogel. Component B, by mass ratio, includes 28 parts of magnesium sulfate heptahydrate, 0.3 parts of citric acid monohydrate, 0.2 parts of sodium citrate, 1 part of sodium sulfate, 1 part of potassium sulfate, 30 parts of water, 1 part of soluble starch, and 0.1 parts of hydroxypropyl methylcellulose. Component C, by mass ratio, includes 540 parts of water, 3 parts of sodium perfluorononenoxybenzenesulfonate, 6 parts of TO-10 isomeric tridecyl alcohol polyoxyethylene ether, and 1 part of silane coupling agent KH550.

[0059] The preparation method of the above-mentioned SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar includes the following steps:

[0060] 1) Mix highly active lightly calcined magnesium oxide with silica aerogel to obtain component A;

[0061] 2) Mix magnesium sulfate heptahydrate, citric acid monohydrate, sodium citrate, sodium sulfate, potassium sulfate, soluble starch, hydroxypropyl methylcellulose, and water evenly to obtain component B;

[0062] 3) Sodium perfluorononenoxybenzenesulfonate, TO-10 isomeric tridecyl alcohol polyoxyethylene ether, silane coupling agent KH550, and water are mixed evenly to obtain component C;

[0063] 4) Add components B and C to component A in sequence, mix evenly and stir to obtain SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation slurry;

[0064] Thermal insulation materials were prepared using the above-mentioned SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar: The prepared SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar was poured into a mold, vibrated and leveled, and then cured for 3 days in an environment with a temperature of 25℃ and a relative humidity of 65%. After demolding, it was cured for 28 days in an environment with a temperature of 25℃ and a relative humidity of 65%.

[0065] Example 6

[0066] A SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar comprises components A, B, C, and D. Component A, by mass ratio, includes 65 parts of highly active lightly calcined magnesium oxide and 20 parts of silica aerogel; component B, by mass ratio, includes 30 parts of magnesium sulfate heptahydrate, 0.4 parts of citric acid monohydrate, 1.5 parts of sodium sulfate, 1 part of potassium sulfate, 29 parts of water, 1 part of soluble starch, 0.3 parts of hydroxypropyl methylcellulose, and 0.5 parts of organosilicon hydrophobic powder; component C, by mass ratio, includes 280 parts of water, 4 parts of TO-10 isotridecyl alcohol polyoxyethylene ether, and 1 part of sodium perfluorononenoxybenzenesulfonate; and component D, by mass ratio, includes 2 parts of polystyrene particles, 3 parts of expanded cork particles, 2 parts of glass fiber, 0.5 parts of PP fiber, and 0.5 parts of wood fiber.

[0067] The preparation method of the above-mentioned SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar includes the following steps:

[0068] 1) Mix highly active lightly calcined magnesium oxide with silica aerogel to obtain component A;

[0069] 2) Mix magnesium sulfate heptahydrate, citric acid monohydrate, sodium sulfate, potassium sulfate, soluble starch, hydroxypropyl methylcellulose, organosilicon hydrophobic powder, and water evenly to obtain component B;

[0070] 3) Sodium perfluorononenoxybenzenesulfonate, TO-10 isomeric tridecyl alcohol polyoxyethylene ether, and water are mixed evenly to obtain component C.

[0071] 4) Add components B and C to component A in sequence, mix evenly and stir to obtain SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation slurry;

[0072] 5) Add the polystyrene particles, expanded cork particles, glass fiber, PP fiber and wood fiber from component D to the SiO2 aerogel / magnesium oxysulfate cement-based slurry and stir evenly to obtain SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar.

[0073] Thermal insulation materials were prepared using the above-mentioned SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar: The prepared SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar was poured into a mold, vibrated and leveled, and then cured for 3 days in an environment with a temperature of 25℃ and a relative humidity of 65%. After demolding, it was cured for 28 days in an environment with a temperature of 25℃ and a relative humidity of 65%.

[0074] Example 7

[0075] A SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar comprises components A, B, C, and D. Component A, by mass ratio, includes 65 parts of highly active lightly calcined magnesium oxide and 10 parts of silica aerogel; component B, by mass ratio, includes 29 parts of magnesium sulfate heptahydrate, 0.3 parts of citric acid monohydrate, 0.1 parts of sodium citrate, 2 parts of sodium sulfate, 31 parts of water, 1.5 parts of xanthan gum, 0.2 parts of hydroxypropyl methylcellulose, and 1 part of organosilicon hydrophobic powder; component C, by mass ratio, includes 120 parts of water, 3 parts of TO-10 isotridecyl alcohol polyoxyethylene ether, and 1 part of sodium perfluorononenoxybenzenesulfonate; and component D, by mass ratio, includes 20 parts of precast foam, 2 parts of polystyrene particles, 0.5 parts of glass fiber, and 0.5 parts of PP fiber.

[0076] The above-mentioned component D is 20 parts of a 2.5 wt% ST-YH-1 solution, which is foamed to obtain pre-made foam.

[0077] The preparation method of the above-mentioned SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar includes the following steps:

[0078] 1) Mix highly active lightly calcined magnesium oxide with silica aerogel to obtain component A;

[0079] 2) Mix magnesium sulfate heptahydrate, citric acid monohydrate, sodium citrate, sodium sulfate, xanthan gum, hydroxypropyl methylcellulose, organosilicon hydrophobic powder, and water evenly to obtain component B;

[0080] 3) Sodium perfluorononenoxybenzenesulfonate, TO-10 isomeric tridecyl alcohol polyoxyethylene ether, and water are mixed evenly to obtain component C.

[0081] 4) Add components B and C to component A in sequence, mix evenly and stir to obtain SiO2 aerogel / magnesium oxysulfate cementitious slurry;

[0082] 5) Add the pre-made foam, polystyrene particles, glass fiber and PP fiber from component D to the SiO2 aerogel / magnesium oxysulfate cement-based slurry in sequence and stir evenly to obtain SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar.

[0083] Thermal insulation materials were prepared using the above-mentioned SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar: The prepared SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar was poured into a mold, vibrated and leveled, and then cured for 3 days in an environment with a temperature of 25℃ and a relative humidity of 65%. After demolding, it was cured for 28 days in an environment with a temperature of 25℃ and a relative humidity of 65%.

[0084] Comparative Example 1

[0085] The difference between Comparative Example 1 and Example 1 is that Component A of Comparative Example 1 does not contain silica aerogel, and Components C and D are not present.

[0086] Comparative Example 2

[0087] The difference between Comparative Example 2 and Example 1 is that the dispersant is 10 parts of FM600 dispersible surfactant.

[0088] Comparative Example 3

[0089] The difference between Comparative Example 3 and Example 1 is that component C of Comparative Example 3 does not contain a dispersant, and component A contains 1 part of silica aerogel.

[0090] Thermal conductivity tests were conducted on the cast samples from Examples 1-7 and Comparative Examples 1-2 using a dual-plate thermal conductivity meter IMDRY3001-Ⅲ. The test samples were 300mm × 300mm × 30mm plates, and the tests were performed according to GB / T10294-2008, "Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials". The compressive strength, dry density, softening coefficient, and combustion performance of the cast samples from Examples 1-7 and Comparative Examples 1-2 were tested according to GB / T 20473-2021, "Building Thermal Insulation Mortar". The results are shown in Table 1.

[0091]

[0092] Data from Comparative Example 1 shows that the addition of aerogel significantly reduces the thermal conductivity and improves the water resistance of magnesium oxysulfate cement, but its strength is significantly reduced. Data from Comparative Example 2 shows that adding excessive dispersant weakens the effect of silica aerogel in reducing thermal conductivity. This is mainly because the addition of excessive dispersant allows cement paste to penetrate into the nanoporous structure of the aerogel, increasing thermal conductivity. Furthermore, a comparison of data from Examples 1-7 shows that both thermal conductivity and compressive strength decrease with increasing silica aerogel content. Adding component D to reduce the amount of silica aerogel not only maintains its excellent performance but also reduces production costs.

[0093] Figure 1 The images show the SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar prepared in Example 1 of this invention and its cured physical product. Figure 1 Image a shows a physical sample of SiO2 aerogel / magnesium oxysulfate cementitious slurry. Figure 1 b is a photograph of the SiO2 aerogel / magnesium oxysulfate cementitious grout after 1 day of curing. Figure 2 c is a physical image of SiO2 aerogel / magnesium oxysulfate cementitious slurry cured for 28 days. As can be seen from the image, the silica aerogel is uniformly dispersed in the cementitious material and there is no interfacial delamination problem.

[0094] Figure 2The image shows physical samples used in the compatibility study of SiO2 aerogel and magnesium oxysulfate cement in Comparative Example 3. From left to right, the three sample groups are: mixture of component A and component B, mixture of SiO2 aerogel and component B, and pure water. The image shows that the mixture of silica aerogel and lightly calcined magnesium oxide makes component A slightly soluble in component B. When only silica aerogel is used, a small amount of component B is found to be soluble. This is mainly because citrate ions have a certain dispersing ability.

[0095] The SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar provided by this invention has the advantage of high strength, light weight, good thermal insulation performance, and high softening coefficient. The large volume aerogel in the SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar can be uniformly dispersed in the cement-based material without the occurrence of problems such as interface delamination.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar, characterized in that, Includes component A, component B, component C, and component D. Component A comprises the following raw materials in parts by weight: 65 parts lightly calcined magnesium oxide and 5-50 parts silica aerogel; Component B comprises the following raw materials in parts by weight: 25-35 parts magnesium sulfate heptahydrate, 0.1-1 parts modifier, 0-3 parts reinforcing agent, 26-32 parts water, 0-3 parts thickener, and 0-3 parts water-repellent agent; Component C comprises the following raw materials in parts by weight: 60-650 parts water and 1-15 parts dispersant; Component D comprises the following raw materials in parts by weight: 0-20 parts inert filler, 0-30 parts pre-made foam, and 0-5 parts fiber; The dispersant is 10% to 60% of the mass of silica aerogel, and the dispersant is one or more of the following: dispersing surfactant FM600, thickening surfactant FM400, BASF TO-10 isotridecyl alcohol polyoxyethylene ether, sodium perfluorononenoxybenzenesulfonate, fatty alcohol polyoxyethylene ether, and sodium fatty alcohol polyoxyethylene ether sulfate. The preparation method of the SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar includes the following steps: S1. Weigh the raw materials according to the weight parts, mix the lightly calcined magnesium oxide and silica aerogel evenly to obtain component A, mix magnesium sulfate heptahydrate, modifier, reinforcing agent, hydrophobic agent, thickener and water evenly to obtain component B, mix the dispersant and water evenly to obtain component C; S2. Add components B and C to component A in sequence, mix evenly and stir to obtain SiO2 aerogel / magnesium oxysulfate cementitious slurry; S3. Add component D to the SiO2 aerogel / sulfur-oxygen magnesium cement-based slurry and stir evenly to obtain SiO2 aerogel / sulfur-oxygen magnesium cement-based thermal insulation mortar.

2. The SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar according to claim 1, characterized in that, The content of active magnesium oxide in the lightly calcined magnesium oxide is 50%-70%, and the silica aerogel is a hydrophobic aerogel with a particle size of 10-100 μm, a porosity of 90%-95%, and a thermal conductivity of 0.012-0.018 W / (m·K).

3. The SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar according to claim 1, characterized in that, The modifier is one or more of citric acid monohydrate, sodium citrate, trisodium phosphate, sodium tripolyphosphate, and tartaric acid; the reinforcing agent is one or two of sodium sulfate and potassium sulfate; the thickening agent is one or more of hydroxypropyl methylcellulose, xanthan gum, soluble starch, and dextrin; and the water-repellent agent is organosilicon water-repellent powder.

4. The SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar according to claim 1, characterized in that, The inert filler is one or more of polystyrene particles, graphite polystyrene particles, and expanded cork particles, and the fiber is one or more of glass fiber, PP fiber, and wood fiber.

5. The SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar according to claim 1, characterized in that, The pre-made foam is obtained by foaming an aqueous solution prepared with 0.1-3wt% ST-YH-1 foaming agent.

6. The method for preparing SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Weigh the raw materials according to the weight parts, mix the lightly calcined magnesium oxide and silica aerogel evenly to obtain component A, mix magnesium sulfate heptahydrate, modifier, reinforcing agent, hydrophobic agent, thickener and water evenly to obtain component B, mix the dispersant and water evenly to obtain component C; S2. Add components B and C to component A in sequence, mix evenly and stir to obtain SiO2 aerogel / magnesium oxysulfate cementitious slurry; S3. Add component D to the SiO2 aerogel / sulfur-oxygen magnesium cement-based slurry and stir evenly to obtain SiO2 aerogel / sulfur-oxygen magnesium cement-based thermal insulation mortar.

7. A SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation material, characterized in that, It is prepared by the following method: the SiO2 aerogel / magnesium oxysulfate cement-based thermal insulation mortar according to any one of claims 1-5 is poured into a mold, vibrated and leveled, and then cured according to standard until demolding, and then cured to the specified age. The standard curing conditions are a temperature of 20℃-30℃ and a relative humidity of 60%-70%.

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