Processing technology of autoclaved aerated concrete thermal insulation wall

Abstract

The invention relates to the technical field of building materials, and discloses an autoclaved aerated concrete thermal insulation wall processing technology which comprises the following steps: S1, thermal insulation core material pretreatment: cutting vertical-wire rock wool into a design size, injecting liquid modified polyurethane into the rock wool through vacuum pressurization equipment under the injection pressure of 0.5-1.5 MPa, and keeping for 30-60 minutes; the modified polyurethane is composed of a polyurethane prepolymer, a water repellent and a guiding agent in a weight ratio of 100: (3-8): (0.5-2); and S2, concrete pouring is conducted, specifically, the pretreated heat preservation core material is fixed in a mold, foamed concrete slurry is poured, the water-cement ratio is 0.45-0.55, and the curing temperature is 50-70 DEG C. The unique modified polyurethane is gasified to form a microporous structure, so that the stress concentration is effectively relieved, the low-temperature anti-cracking index is greatly improved, and the durability and stability of the wall body in a low-temperature environment are greatly enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, in particular to a steam-cured aerated concrete thermal insulation wall processing technology. BACKGROUND

[0002] Steam-cured aerated concrete thermal insulation walls have been widely used in the construction field due to their lightweight, thermal insulation, sound insulation and other advantages. However, the existing steam-cured aerated concrete thermal insulation walls still have deficiencies in low-temperature crack resistance, water absorption rate and overall thermal insulation performance. In a low-temperature environment, the wall is prone to cracking, affecting its structural stability and service life; a higher water absorption rate can cause water accumulation in the wall, reducing the thermal insulation effect and possibly causing freeze-thaw damage and other problems. Therefore, it is of great practical significance to develop a steam-cured aerated concrete thermal insulation wall processing technology that can effectively improve low-temperature crack resistance and reduce water absorption rate. SUMMARY

[0003] In view of the deficiencies of the prior art, the present application provides a steam-cured aerated concrete thermal insulation wall processing technology, which significantly improves the low-temperature crack resistance of the thermal insulation wall and reduces the water absorption rate through a series of innovative steps such as pretreatment of the thermal insulation core material, preparation of modified polyurethane and high-temperature steam curing, to meet the demand for high-performance thermal insulation walls in the construction field.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical solution: a steam-cured aerated concrete thermal insulation wall processing technology, comprising the following steps: S1, thermal insulation core material pretreatment: cutting vertical filament rock wool to the designed size, injecting liquid modified polyurethane into the rock wool through a vacuum pressurization device, the injection pressure being 0.5MPa~1.5MPa, and maintaining for 30min~60min; the modified polyurethane is composed of polyurethane prepolymer, hydrophobic agent and directing agent, with a weight ratio of 100:3~8:0.5~2; S2, concrete pouring: fixing the pretreated thermal insulation core material in a mold, pouring foamed concrete slurry with a water-cement ratio of 0.45~0.55, and curing at a temperature of 50℃~70℃; S3, high-temperature steam curing: curing at 180℃~200℃ and 1.2MPa~1.5MPa steam pressure for 8h~12h, so that the modified polyurethane gasifies and is discharged from the concrete airway, forming a microporous structure.

[0005] Preferably, the preparation method of the directing agent comprises the following steps: a. mixing 30~50 parts by weight of silane coupling agent KH-550, 5~10 parts by weight of nano-silicon dioxide and 10~20 parts by weight of graphene dispersion liquid; b. processing in an ultrasonic oscillator with a frequency of 40kHz for 30min~60min; c. Add 2-5 parts by weight of polyvinyl butyral and stir at 60℃-80℃ until completely dissolved.

[0006] Preferably, the guiding agent consists of 40 parts by weight of silane coupling agent KH-550, 8 parts by weight of nano-silica, 15 parts by weight of graphene dispersion, and 3 parts by weight of polyvinyl butyral.

[0007] Preferably, the water-repellent agent is a mixture of organosilicon resin and calcium stearate in a weight ratio of 2:1 to 5:1.

[0008] Preferably, the vacuum degree is -0.08MPa to -0.1MPa, and the pressurization stage is divided into 3 steps with an interval of 5 minutes between each pressurization.

[0009] Preferably, the method for preparing the modified polyurethane includes the following steps: A. Prepolymer synthesis: Polyether polyol (molecular weight 3000~5000) and polyisocyanate (MDI) are mixed at a molar ratio of -OH to -NCO of 1:1.2~1:1.5, and reacted at 80℃~90℃ for 2h~3h under nitrogen protection to obtain polyurethane prepolymer; B. Hydrophobic agent composite: Dissolve organosilicon resin and calcium stearate in xylene at a weight ratio of 3:1 to 5:1, and ultrasonically disperse for 20 to 30 minutes to form a hydrophobic agent suspension. C. Initiator loading: The initiator is mixed with n-heptane at a volume ratio of 1:5 to 1:10, and emulsified by high-speed shearing at a speed of 8000 rpm to 12000 rpm for 15 min to 30 min to form nano-sized micelles. D. Blending modification: The prepolymer is cooled to 50℃~60℃, and a water-repellent suspension (3wt.%~8wt.%) and a guiding agent micelle (0.5wt.%~2wt.%) are added sequentially. The mixture is stirred and degassed under a vacuum of -0.05MPa~-0.08MPa for 1h~2h to obtain liquid modified polyurethane.

[0010] Preferably, the high-speed shear emulsification temperature is 25℃~35℃, the micelle size is 50nm~200nm, the viscosity of the modified polyurethane is controlled at 800mPa·s~1200mPa·s (25℃), the surface tension is ≤25mN / m, the ultrasonic dispersion frequency is 40kHz, and the power density is 0.5W / cm³. 3 ~1.0W / cm 3 .

[0011] Preferably, after autoclaved curing in the high-temperature autoclaved curing, the concrete surface forms connected micropores with a pore size of 50-200 mu m, the porosity increases by 5-8%, and the foamed concrete slurry comprises 40-60% of Portland cement, 20-30% of fly ash and 0.1-0.3% of a foaming agent (aluminum powder).

[0012] Preferably, the low-temperature crack resistance index (residual rate of flexural strength after 50 freeze-thaw cycles at -20 DEG C) is greater than or equal to 85%, and the water absorption is less than or equal to 5%.

[0013] Preferably, the thermal conductivity is less than or equal to 0.12 W / (m*K), and the compressive strength is greater than or equal to 3.5 MPa.

[0014] Compared with the prior art, the present application provides a steam pressure aerated concrete thermal insulation wall processing technology, which has the following beneficial effects: from the low-temperature crack resistance, the unique modified polyurethane gasification forms a microporous structure, effectively relieves stress concentration, greatly improves the low-temperature crack resistance index, and greatly enhances the durability and stability of the wall in a low-temperature environment. In terms of water absorption, the synergistic effect of the hydrophobic agent and the modified polyurethane significantly reduces the water absorption and reduces various problems caused by water intrusion. In terms of thermal conductivity, the microporous structure formed by the modified polyurethane plays a good thermal insulation role, effectively improving the energy utilization efficiency of the building; in terms of compressive strength, the process of the present application, by virtue of reasonable raw material ratio, preparation process and stress dispersion effect of the microporous structure, significantly improves the compressive strength of the wall, meeting the mechanical requirements of the building structure. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0016] Low-temperature crack resistance, test standard: according to the relevant provisions of the low-temperature crack resistance of the thermal insulation wall in the "JGJ144-2019 External Wall External Insulation Engineering Technical Standard".

[0017] Test method: cut the prepared thermal insulation wall test piece into a specified size, put it into a low temperature test box, and freeze-thaw cycle test is carried out according to the temperature condition of-20℃. After each freeze-thaw cycle (frozen stage: keep at-20℃ for a specified time; thawing stage: soak in water at a certain temperature for a specified time), the test piece is tested for bending strength. After 50 freeze-thaw cycles, the bending strength retention rate is calculated, that is, the ratio of the bending strength after 50 freeze-thaw cycles to the initial bending strength, which is taken as the low temperature crack resistance index.

[0018] Water absorption, test standard: refer to the standard for water absorption test in GB / T2542-2012 "Test method for wall brick".

[0019] Test method: select thermal insulation wall test pieces of the required size, first dry the test pieces in an oven at (105±5)℃ to constant weight, and record the mass m1 of the test pieces at this time. Then soak the dried test pieces in room temperature water for 48h, remove the surface moisture with a wet cloth, and immediately weigh the test pieces to get the mass m2. The water absorption formula is: (m2-m1) / m1×100%.

[0020] Thermal conductivity, test standard: follow GB / T10294-2008 "Determination of thermal resistance and related properties of thermal insulation materials by guarded hot plate method" for testing.

[0021] Test method: process the thermal insulation wall test piece into a size and shape that meets the requirements of the guarded hot plate method, and install it in the guarded hot plate device. Under steady state conditions, measure the heat flow through the test piece, the cold and hot surface temperature of the test piece, and the geometric size of the test piece, etc. The thermal conductivity of the test piece is calculated.

[0022] Compressive strength, test standard: follow the provisions of GB / T11969-2020 "Test method for performance of autoclaved aerated concrete" for compressive strength test.

[0023] Test method: cut the thermal insulation wall test piece into a standard size cubic test piece, and cure it at (20±5)℃ to a specified age. Then place the test piece on a pressure testing machine and apply pressure uniformly at a specified loading speed until the test piece fails, and record the failure load value. According to the compression area of the test piece, the compressive strength of the test piece is calculated.

[0024] The common preparation method of autoclaved aerated concrete thermal insulation wall on the market is usually to use ordinary rock wool as the thermal insulation core material without special pretreatment. The foamed concrete slurry is prepared by using Portland cement 55%, fly ash 25%, foaming agent (aluminum powder) 0.2%, and water-cement ratio 0.5. After curing at room temperature, it is cured at 180℃ and 1.2MPa steam pressure for 10h.

[0025] The relevant test equipment used in the present application is as follows, which is not specifically limited, and the corresponding test purposes can be achieved: Low temperature test chamber: for example, GDJS-1000 high and low temperature test chamber produced by Ningbo Haishu Saifu Test Instrument Factory, which can accurately control the temperature, meet the low temperature environment requirement of-20℃, and the internal space can accommodate the specified size of the thermal insulation wall body test piece for freeze-thaw cycle test.

[0026] Bending strength testing machine: WDW-100 microcomputer controlled electronic universal testing machine of Jinan Zhongchuang Testing Machine Factory, which has a high precision force value measurement system and can accurately measure the bending strength of the test piece at different stages, meeting the detection requirements of the bending strength of the test piece in the low temperature crack resistance performance test.

[0027] Oven: DHG-9070A electric heating constant temperature air drying oven of Shanghai Yiheng Scientific Instrument Co., Ltd., which can stably control the temperature at (105±5)℃, and ensure that the test piece is dried to constant weight, so as to accurately measure the mass.

[0028] Electronic balance: ME204E / 02 electronic balance of Mettler-Toledo, with an accuracy of 0.0001g, which can accurately measure the mass of the test piece before and after drying, and provide accurate data for the calculation of water absorption rate.

[0029] Protective hot plate device: DRPL-II type protective hot plate heat conduction instrument of Xiangtan Xiangyi Instrument Co., Ltd., which is strictly designed according to the standard of GB / T10294-2008, and can accurately measure the heat flow and cold and hot surface temperature of the test piece under stable state conditions, and then accurately calculate the thermal conductivity of the test piece.

[0030] Pressure testing machine: YE-2000B type pressure testing machine of Wuxi Jianyi Instrument & Machinery Co., Ltd., with a maximum test force of 2000kN, and uniform and stable loading speed, which can apply pressure to the standard size cubic test piece until it is damaged, and accurately record the damage load value, which is used to calculate the compressive strength.

[0031] Example one A autoclaved aerated concrete thermal insulation wall body processing technology, comprising the following steps: The preparation steps of the guiding agent are as follows: Mixing: mix 30 parts by weight of silane coupling agent KH-550, 5 parts by weight of nano silicon dioxide and 10 parts by weight of graphene dispersion liquid; Ultrasonic treatment: treat in an ultrasonic oscillator with a frequency of 40kHz for 30min; Dissolution: add 2 parts by weight of polyvinyl butyral and stir at 60℃ until completely dissolved.

[0032] The preparation steps of the modified polyurethane are as follows: Prepolymer synthesis: polyether polyol with molecular weight of 3000 was mixed with polyisocyanate (MDI) at -OH and -NCO molar ratio of 1:1.2, reacted at 80°C for 2h under nitrogen protection, to prepare polyurethane prepolymer; Hydrophobic agent compounding: silicone resin and calcium stearate were dissolved in xylene at weight ratio of 3:1, ultrasonic dispersed for 20min at frequency of 40kHz and power density of 0.5W / cm³, to form hydrophobic agent suspension; Guiding agent loading: guiding agent was mixed with n-heptane at volume ratio of 1:5, high speed sheared and emulsified at 8000rpm for 15min at 25°C, to form nanoscale micelles; Blending modification: the prepolymer was cooled to 50°C, 3wt.% of the hydrophobic agent suspension and 0.5wt.% of the guiding agent micelles were added in sequence, and defoaming was performed under vacuum degree of-0.05MPa for 1h, to obtain liquid modified polyurethane.

[0033] The preparation steps of the thermal insulation wall body are as follows: Thermal insulation core material pretreatment: the vertical filament rock wool was cut into the designed size, the vacuum degree of the vacuum pressurization equipment was set to-0.08MPa, the pressurization stage was divided into three steps, each step was raised by 0.5MPa, and the interval was 5min, and the injection pressure was 0.5MPa, and the pressure was maintained for 30min; Concrete pouring: the pretreated thermal insulation core material was fixed in the mold, and the foamed concrete slurry (portland cement 40%, fly ash 30%, foaming agent (aluminum powder) 0.1%) was poured, the water-cement ratio was 0.45, and the curing temperature was 50°C; High-temperature autoclave curing: curing at 180°C and 1.2MPa steam pressure for 8h.

[0034] Example two A processing technology of autoclaved aerated concrete thermal insulation wall body, comprising the following steps: The guiding agent preparation steps are as follows: Mixing: 40 parts by weight of silane coupling agent KH-550, 8 parts by weight of nano silicon dioxide and 15 parts by weight of graphene dispersion liquid were mixed; Ultrasonic treatment: treated in an ultrasonic oscillator at a frequency of 40kHz for 45min; Dissolution: 3 parts by weight of polyvinyl butyral was added and stirred at 70°C until completely dissolved.

[0035] The modified polyurethane preparation steps are as follows: Prepolymer synthesis: polyether polyol with molecular weight of 4000 was mixed with polyisocyanate (MDI) at -OH and -NCO molar ratio of 1:1.3, reacted at 85°C for 2.5h under nitrogen protection, to prepare polyurethane prepolymer; Hydrophobic agent complexing: the silicone resin and calcium stearate were dissolved in xylene at a weight ratio of 4:1, ultrasonically dispersed at a frequency of 40 kHz and a power density of 0.7 W / cm³ for 25 min to form a hydrophobic agent suspension; Guiding agent loading: the guiding agent was mixed with n-heptane at a volume ratio of 1:7, high-speed sheared and emulsified at a speed of 10000 rpm for 20 min at 30°C to form nanoscale micelles; Blending modification: the prepolymer was cooled to 55°C, 5wt.% of the hydrophobic agent suspension and 1wt.% of the guiding agent micelles were sequentially added, and defoaming was performed under a vacuum degree of-0.06 MPa for 1.5 h to obtain a liquid modified polyurethane.

[0036] The preparation steps of the thermal insulation wall body are as follows: Thermal insulation core material pretreatment: the vertical filament rock wool was cut to the designed size, the vacuum degree of the vacuum pressurization equipment was set to-0.09 MPa, the pressurization stage was divided into three steps, each step was raised by 1.0 MPa, and the interval was 5 min, and the injection pressure was maintained for 45 min; Concrete pouring: the pretreated thermal insulation core material was fixed in the mold, and the foamed concrete slurry (portland cement 50%, fly ash 25%, foaming agent (aluminum powder) 0.2%) was poured, the water-cement ratio was 0.5, and the curing temperature was 60°C; High-temperature autoclave curing: curing at 190°C and 1.3 MPa steam pressure for 10 h.

[0037] Example Three A autoclaved aerated concrete thermal insulation wall body processing technology, comprising the following steps: The guiding agent preparation steps are as follows: Mixing: 50 parts by weight of silane coupling agent KH-550, 10 parts by weight of nano-silicon dioxide, and 20 parts by weight of graphene dispersion liquid were mixed; Ultrasonic treatment: treated in an ultrasonic oscillator at a frequency of 40 kHz for 60 min; Dissolution: 5 parts by weight of polyvinyl butyral was added and stirred at 80°C until completely dissolved.

[0038] The preparation steps of the modified polyurethane are as follows: Prepolymer synthesis: polyether polyol with a molecular weight of 5000 and polyisocyanate (MDI) were mixed at an -OH to -NCO molar ratio of 1:1.5, reacted at 90°C for 3 h under nitrogen protection, and polyurethane prepolymer was prepared; Hydrophobic agent complexing: the silicone resin and calcium stearate were dissolved in xylene at a weight ratio of 4:1, ultrasonically dispersed at a frequency of 40 kHz and a power density of 0.7 W / cm³ for 25 min to form a hydrophobic agent suspension; The guiding agent is mixed with n-heptane at a volume ratio of 1:10, and is emulsified at 35°C for 30 min at a high speed shearing speed of 12000 rpm to form nanoscale micelles; Blending modification: the prepolymer is cooled to 60°C, 8wt.% of the hydrophobic agent suspension and 2wt.% of the guiding agent micelles are sequentially added, and is stirred and defoamed under a vacuum degree of-0.08 MPa for 2 h to obtain a liquid modified polyurethane.

[0039] The preparation steps of the thermal insulation wall are as follows: Thermal insulation core material pretreatment: the vertical filament rock wool is cut into a designed size, the vacuum degree of the vacuum and pressure equipment is set to-0.1 MPa, the pressure is increased in three steps, each time with an interval of 5 min, the injection pressure is 1.5 MPa, and the pressure is maintained for 60 min; Concrete pouring: the pretreated thermal insulation core material is fixed in the mold, and the foamed concrete slurry (portland cement 60%, fly ash 20%, foaming agent (aluminum powder) 0.3%) is poured, the water-cement ratio is 0.55, and the curing temperature is 70°C; High-temperature autoclave curing: curing at 200°C and 1.5 MPa steam pressure for 12 h.

[0040] Comparative Example One The vertical filament rock wool is directly fixed in the mold without pretreatment of the thermal insulation core material, the foamed concrete slurry (portland cement 50%, fly ash 25%, foaming agent (aluminum powder) 0.2%) is poured, the water-cement ratio is 0.5, the curing temperature is 60°C, and the curing is performed at 190°C and 1.3 MPa steam pressure for 10 h.

[0041] Comparative Example Two The unmodified polyurethane is injected into the vertical filament rock wool, and the other steps are the same as those in Example Two.

[0042] Comparative Example Three The commonly used method for preparing a concrete thermal insulation wall is selected.

[0043] Comparative Example Four The modified polyurethane is injected into the thermal insulation core material in the same way as in Example Two, but the temperature and pressure are controlled in the high-temperature autoclave curing stage to prevent the modified polyurethane from being vaporized and discharged (100°C, 0.5 MPa curing for 10 h).

[0044] The thermal insulation walls of the examples and comparative examples are tested for low-temperature crack resistance, water absorption, thermal conductivity, and tensile strength, and the test results are shown in Tables 1 and 2.

[0045] Table 1 Test results of examples and comparative examples on low-temperature crack resistance and water absorption Table 2 Test results of examples and comparative examples on thermal conductivity and tensile strength From the above experimental data, it can be clearly seen that the low-temperature crack resistance is significantly improved: the low-temperature crack resistance indexes of comparative examples one to four are 70%, 75%, 72% and 78% respectively, while the low-temperature crack resistance indexes of examples one to three are as high as 86%, 88% and 89%. Among them, the comparison between comparative example four and example two is particularly prominent. The early treatment of the two is similar, and only because the modified polyurethane of comparative example four is not gasified and discharged, the low-temperature crack resistance index is much lower than that of example two. This clearly shows that the microporous structure formed by the gasification of modified polyurethane can effectively relieve low-temperature stress concentration and greatly improve the durability and stability of the wall in a low-temperature environment; The water absorption is significantly reduced: the water absorption of comparative examples one to four is 8.0%, 7.0%, 7.5% and 6.5% respectively, while the water absorption of examples one to three is only 4.8%, 4.5% and 4.2%. The process of the present application significantly reduces the surface energy of the material by adding a hydrophobic agent and filling the pores of the thermal insulation core material with modified polyurethane, effectively prevents water from entering, and greatly reduces the freeze-thaw damage and wall mildew caused by water; The thermal conductivity is lower and the thermal insulation performance is better: the thermal conductivities of comparative examples one to four are 0.15 W / (m·K), 0.14 W / (m·K), 0.13 W / (m·K) and 0.13 W / (m·K) respectively, and the thermal conductivities of examples one to three are as low as 0.11 W / (m·K), 0.10 W / (m·K) and 0.09 W / (m·K). The microporous structure formed by the gasification of modified polyurethane plays a good thermal insulation role, effectively hinders heat transfer, reduces the thermal conductivity of the wall, significantly improves the energy utilization efficiency of the building, and reduces energy consumption; The compressive strength is higher, meeting the mechanical requirements: the compressive strengths of comparative examples one to four are 3.0 MPa, 3.2 MPa, 3.1 MPa and 3.3 MPa respectively, and the compressive strengths of examples one to three are 3.6 MPa, 3.8 MPa and 4.0 MPa. The microporous structure under the process of the present application can effectively disperse stress, combined with reasonable raw material ratio and preparation process, greatly improving the compressive performance of the wall, fully protecting the wall from damage due to external force in long-term use, meeting the mechanical requirements of building structure.

[0046] The above is only a specific embodiment of the present application, but the technical features of the present application are not limited to this. Any simple change, equivalent replacement or modification made on the basis of the present application to solve basically the same technical problem and achieve basically the same technical effect is covered by the protection scope of the present application.

Claims

1. A process for manufacturing autoclaved aerated concrete thermal insulation wall, characterized in that: The method comprises the following steps: S1, pre-treatment of the thermal insulation core material: cutting the vertical rock wool into a designed size, injecting liquid modified polyurethane into the rock wool through a vacuum pressurization device, the injection pressure being 0.5-1.5 MPa, and keeping for 30-60 min; the modified polyurethane is composed of polyurethane prepolymer, hydrophobic agent and guiding agent, and the weight ratio is 100:3-8:0.5-2; S2, concrete pouring: fixing the pre-treated thermal insulation core material in a mold, pouring foamed concrete slurry, the water-cement ratio being 0.45-0.55, and the curing temperature being 50-70 ℃; S3, high-temperature autoclave curing: curing at 180-200 ℃ and 1.2-1.5 MPa steam pressure for 8-12 h, so that the modified polyurethane is gasified and discharged from the concrete air duct to form a microporous structure.

2. The autoclaved aerated concrete thermal insulation wall processing process according to claim 1, characterized in that: The preparation method of the guiding agent comprises the following steps: a. mixing 30-50 parts by weight of silane coupling agent KH-550, 5-10 parts by weight of nano-silicon dioxide and 10-20 parts by weight of graphene dispersion liquid; b. processing in an ultrasonic oscillator with a frequency of 40 kHz for 30-60 min; c. adding 2-5 parts by weight of polyvinyl butyral, and stirring at 60-80 ℃ until completely dissolved.

3. The autoclaved aerated concrete thermal insulation wall processing process according to claim 2, characterized in that: The components of the guiding agent are 40 parts by weight of silane coupling agent KH-550, 8 parts by weight of nano-silicon dioxide, 15 parts by weight of graphene dispersion liquid and 3 parts by weight of polyvinyl butyral.

4. The autoclaved aerated concrete thermal insulation wall processing process according to claim 1, characterized in that: The hydrophobic agent is a mixture of silicone resin and calcium stearate, and the weight ratio is 2:1-5:

1.

5. The autoclaved aerated concrete thermal insulation wall processing process according to claim 1, characterized in that: The working parameters of the vacuum pressurization device in the pre-treatment of the thermal insulation core material are as follows: vacuum degree -0.08-0.1 MPa, and the pressurization stage is divided into three times of stepwise pressurization, and the interval of each pressurization is 5 min.

6. The autoclaved aerated concrete thermal insulation wall processing process according to claim 1, characterized in that: The preparation method of the modified polyurethane comprises the following steps: A. prepolymer synthesis: mixing polyether polyol and polyisocyanate (MDI) according to the molar ratio of -OH to -NCO of 1:1.2-1:1.5, and reacting at 80-90 ℃ for 2-3 h under nitrogen protection to prepare polyurethane prepolymer; B. hydrophobic agent compounding: dissolving silicone resin and calcium stearate in dimethylbenzene according to the weight ratio of 3:1-5:1, ultrasonic dispersion for 20-30 min to form a hydrophobic agent suspension; C. guiding agent loading: mixing the guiding agent and n-heptane according to the volume ratio of 1:5-1:10, high-speed shearing emulsification, the rotation speed being 8000-12000 rpm, and the time being 15-30 min to form nanoscale micelles; D. blending modification: cooling the prepolymer to 50-60 ℃, sequentially adding 3-8 wt.% of the hydrophobic agent suspension and 0.5-2 wt.% of the guiding agent micelles, and stirring and defoaming under a vacuum degree of -0.05 to -0.08 MPa for 1-2 h to obtain liquid modified polyurethane.

7. The autoclaved aerated concrete thermal insulation wall processing process according to claim 6, characterized in that: The temperature of the high-speed shearing emulsification is 25-35℃, the micelle particle size is 50-200nm, the viscosity of the modified polyurethane is controlled at 800-1200mPa·s, the surface tension is ≤25mN / m, the frequency of the ultrasonic dispersion is 40kHz, and the power density is 0.5-1.0W / cm 3 . 3 .

8. The autoclaved aerated concrete thermal insulation wall processing process according to claim 1, characterized in that: The high-temperature steam pressure curing forms connected micropores with a pore diameter of 50-200 microns on the surface of the concrete after steam pressure curing, and the porosity increases by 5-8%, the foamed concrete slurry comprises 40-60% of Portland cement, 20-30% of fly ash and 0.1-0.3% of foaming agent.

9. A thermal insulation wall, characterized in that: The process is prepared by any one of claims 1-8, the low-temperature crack resistance index is greater than or equal to 85%, and the water absorption rate is less than or equal to 5%.

10. The thermal wall of claim 9, wherein: The thermal conductivity is less than or equal to 0.12 W / (m*K), and the compressive strength is greater than or equal to 3.5 MPa.

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