A polyurethane composite aerogel sheet and a preparation method and application thereof

Abstract

The application provides a polyurethane composite aerogel sheet and a preparation method and application thereof, and belongs to the technical field of building waterproof and heat insulation materials.The polyurethane composite aerogel sheet has a structure of dense surface and porous interior; the components of the polyurethane composite aerogel sheet include 100 parts of polyurethane, 5-15 parts of sheet-shaped micro-nano particles and 10-20 parts of spherical micro-nano particles in terms of weight fraction. The polyurethane composite aerogel sheet is prepared by dissolving raw materials, performing solvent exchange in a poor solvent and then drying. The polyurethane composite aerogel sheet provided by the application has good abilities of reflecting sunlight and emitting thermal radiation through the synergistic cooperation of materials and structures, improves surface hydrophobicity, can achieve the effect of "no energy consumption refrigeration", and has a slight damage on the surface without obvious influence on the waterproof effect, and has a self-cleaning function, and can be used as a building waterproof and heat insulation material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of building waterproof and heat insulation materials, and particularly relates to a polyurethane composite aerogel sheet and a preparation method and application thereof. BACKGROUND

[0002] With the development of building greenization and energy saving, the heat preservation and waterproof integrated material realizes the functions of building heat preservation and waterproof by material and structure innovation. However, the existing material is mainly formed by on-site spraying technology, and for large-area construction scenes, there are problems of low construction efficiency, poor pore structure and size stability, and poor refrigeration effect.

[0003] The pore structure of the existing waterproof aerogel material on the market is usually formed by foaming agent foaming, and there are problems of unstable pore structure and uneven size. Moreover, the insulation performance of the waterproof aerogel mainly depends on the porous structure, and does not have the "refrigeration effect" or has poor "refrigeration effect". In addition, the hydrophobicity of the existing waterproof aerogel is also poor, and the waterproof function completely depends on the dense structure, which also leads to great influence of structure damage on the waterproof effect. SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a polyurethane composite aerogel sheet and a preparation method and application thereof. The polyurethane composite aerogel sheet has good ability to reflect sunlight and emit thermal radiation, and can achieve the effect of "no energy consumption refrigeration". Moreover, the polyurethane composite aerogel sheet has a super-hydrophobic surface, can make slight damage not obviously affect the waterproof effect, and has a self-cleaning function.

[0005] To achieve this purpose, the following technical solutions are adopted in the present application:

[0006] In a first aspect, the present application provides a polyurethane composite aerogel sheet, which has a structure of dense surface and porous interior.

[0007] The components of the polyurethane composite aerogel sheet include, by weight fraction:

[0008] 100 parts of polyurethane, 5-15 parts of sheet-shaped micro-nano particles and 10-20 parts of spherical micro-nano particles.

[0009] The polyurethane composite aerogel sheet provided by the present application has a dense surface and a large number of pores in the interior. The skeleton material includes a polyurethane continuous phase, and sheet-shaped micro-nano particles and spherical micro-nano particles uniformly dispersed in the polyurethane continuous phase.

[0010] The polyurethane composite aerogel sheet has good sunlight reflection and heat radiation emission capacity and super-hydrophobic surface through the synergistic cooperation of the material and structure, and good heat insulation and waterproof performance are achieved.

[0011] In terms of heat insulation: the flaky micro-nano particles can effectively improve the sunlight back reflection of the polyurethane composite aerogel sheet, and prevent sunlight from penetrating the sheet to cause the substrate to absorb sunlight and heat up. The spherical micro-nano particles have a large scattering cross section, can effectively scatter sunlight, and thus improve the sunlight reflectivity of the polyurethane composite aerogel sheet; and the spherical micro-nano particles have a high infrared emissivity and a high thermal radiation efficiency. The porous structure in the polyurethane composite aerogel sheet itself can improve the sunlight reflectivity. The polyurethane material itself has a high infrared emission capacity. The polyurethane composite aerogel sheet has good sunlight reflection and heat radiation emission capacity through the synergistic cooperation of the flaky micro-nano particles, the spherical micro-nano particles, the polyurethane matrix and the porous structure, and can achieve the effect of "no energy consumption refrigeration".

[0012] In terms of waterproof: the flaky micro-nano particles and the spherical micro-nano particles can form a special rough micro-morphology on the surface of the polyurethane composite aerogel sheet, can significantly improve the hydrophobicity of the surface of the polyurethane composite aerogel sheet, and in combination with the dense structure of the surface of the polyurethane composite aerogel sheet, the polyurethane composite aerogel sheet has good waterproof performance. Moreover, the improvement of the hydrophobicity can also make the slight damage not obviously affect the waterproof effect, and make the polyurethane composite aerogel sheet have a self-cleaning function.

[0013] In the present application, the weight fraction of the flaky micro-nano particles can be any value within 5-15 parts, for example, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts or 15 parts, etc., based on 100 parts of the polyurethane.

[0014] The weight fraction of the spherical micro-nano particles can be any value within 10-20 parts, for example, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts or 20 parts, etc., based on 100 parts of the polyurethane.

[0015] In the present application, the content of the flaky micro-nano particles and the spherical micro-nano particles is controlled within the above range, which is helpful to obtain the polyurethane composite aerogel sheet with good heat insulation, waterproof and mechanical properties. If the content of the flaky micro-nano particles and the spherical micro-nano particles is too low, the corresponding effect is limited, which will cause the heat insulation and waterproof performance of the polyurethane composite aerogel sheet to decrease; if the content of the flaky micro-nano particles and the spherical micro-nano particles is too high, the mechanical properties of the polyurethane composite aerogel sheet will decrease, which is not conducive to practical application.

[0016] In some embodiments of the present application, the visible light refractive index of the sheet-shaped micro-nanoparticles is ≥1.4; for example, it can be 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, 2, 2.05, 2.1, etc. However, the present application is not limited to the listed values, and other unlisted values within this range are also applicable.

[0017] In the present application, the sheet-shaped micro-nanoparticles with high visible light refractive index are selected, which helps to further improve the solar back reflection ability of the sheet-shaped micro-nanoparticles, and thus improve the solar reflectivity of the polyurethane composite aerogel sheet.

[0018] In some embodiments of the present application, the sheet layer thickness of the sheet-shaped micro-nanoparticles is ≤5 μm, for example, it can be 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 50 nm, 60 nm, 80 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 400 nm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.2 μm, 1.3 μm, 1.5 μm, 1.6 μm, 1.8 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, or 5 μm, etc. However, the present application is not limited to the listed values, and other unlisted values within this range are also applicable.

[0019] In the present application, under the condition of the same content, the smaller the sheet layer thickness of the sheet-shaped micro-nanoparticles (the minimum is single layer), the higher the solar reflectivity of the polyurethane composite aerogel sheet; but reducing the sheet layer thickness requires peeling the sheet layer of the sheet-shaped micro-nanoparticles, which will increase the cost. The present application selects sheet-shaped micro-nanoparticles with a sheet layer thickness ≤5 μm, which can ensure that the polyurethane composite aerogel sheet has good solar reflection effect while taking into account the cost.

[0020] In some embodiments of the present application, the sheet layer diameter of the sheet-shaped micro-nanoparticles is 0.5-100 μm; for example, it can be 0.5 μm, 1 μm, 3 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm, etc. However, the present application is not limited to the listed values, and other unlisted values within this range are also applicable.

[0021] In the present application, under the condition of the same content, the larger the flake layer diameter of the flaky micro-nanoparticles is, the higher the solar reflectivity of the polyurethane composite aerogel sheet is; but the flake layer diameter that is too large is not easy to realize on the one hand, and on the other hand, it will affect the continuity of the polyurethane matrix and affect the mechanical properties of the polyurethane composite aerogel sheet. Therefore, the flake layer diameter of the flaky micro-nanoparticles in the present application is preferably controlled within the above range.

[0022] In some embodiments of the present application, the flaky micro-nanoparticles are selected from one or more of boron nitride, zinc oxide, cerium fluoride, montmorillonite and clay.

[0023] In some embodiments of the present application, the D50 of the spherical micro-nanoparticles is 0.1-10 μm. 90 The particle size is 10 nm-3 μm; for example, it can be 10 nm, 20 nm, 30 nm, 50 nm, 60 nm, 80 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2 μm, 2.2 μm, 2.5 μm, 2.8 μm or 3 μm, etc. However, the present application is not limited to the listed values, and other unlisted values within the range are also applicable.

[0024] The particle size range is close to the wavelength of sunlight, which helps to further improve the scattering ability of the spherical micro-nanoparticles to sunlight, and in turn improve the solar reflectivity of the polyurethane composite aerogel sheet.

[0025] In some embodiments of the present application, the visible light refractive index of the spherical micro-nanoparticles is ≥1.4; for example, it can be 1.4, 1.42, 1.45, 1.48, 1.5, 1.52, 1.55, 1.58, 1.6, 1.65, 1.7, 1.75 or 1.8, etc. However, the present application is not limited to the listed values, and other unlisted values within the range are also applicable.

[0026] In the present application, the spherical micro-nanoparticles with high visible light refractive index are selected, which helps to further improve the scattering ability of the spherical micro-nanoparticles to sunlight, and in turn improve the solar reflectivity of the polyurethane composite aerogel sheet.

[0027] In some embodiments of the present application, the water contact angle of the spherical micro-nanoparticles is ≥130°; for example, it can be 130°, 132°, 135°, 138°, 140°, 142°, 145°, 148°, 150°, 152°, 155°, 158° or 160°, etc. However, the present application is not limited to the listed values, and other unlisted values within the range are also applicable.

[0028] In the present application, the spherical micro-nanoparticles with high hydrophobicity are selected, and the special rough micro-morphology of the polyurethane composite aerogel sheet surface is combined, which is helpful to further improve the hydrophobicity of the polyurethane composite aerogel sheet surface, thereby improving the waterproof performance thereof.

[0029] As a non-limiting example of the present application, the spherical micro-nanoparticles are selected from one or more of hydrophobic silicon dioxide, hydrophobic zinc oxide, hydrophobic titanium dioxide, hydrophobic calcium titanate and hydrophobic calcium carbonate.

[0030] The present application does not make special restrictions on the way of hydrophobic modification, and the exemplary modification can be modified by using fluorine-containing silane coupling agent.

[0031] In some embodiments of the present application, the polyurethane composite aerogel sheet further comprises one or more of the following ingredients in the following weight fractions: 1-3 parts of a cell stabilizer, 0.3-0.5 parts of a light stabilizer, and 0.1-0.5 parts of an antioxidant.

[0032] The weight fraction of the cell stabilizer can be any value within 1-3 parts, for example, it can be 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts or 3 parts, etc. However, the present application is not limited to the listed values, and other unlisted values within the range are also applicable.

[0033] The weight fraction of the light stabilizer can be any value within 0.3-0.5 parts, for example, it can be 0.3 parts, 0.32 parts, 0.35 parts, 0.38 parts, 0.4 parts, 0.42 parts, 0.45 parts, 0.48 parts or 0.5 parts, etc. However, the present application is not limited to the listed values, and other unlisted values within the range are also applicable.

[0034] The weight fraction of the antioxidant can be any value within 0.1-0.5 parts, for example, it can be 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts or 0.5 parts, etc. However, the present application is not limited to the listed values, and other unlisted values within the range are also applicable.

[0035] In the present application, the materials of the cell stabilizer, the light stabilizer and the antioxidant are not specially limited, which can be conventional materials known in the art. As a non-limiting example, the cell stabilizer includes but is not limited to polysiloxane-polyoxyalkylene block copolymer, silane-polyether copolymer, sulfonated sodium castor oil, Turkey red oil, etc.; the light stabilizer includes but is not limited to benzotriazole, benzophenone, triazine, hindered amine, phosphite, etc.; and the antioxidant includes but is not limited to phenylenediamine, phosphite, etc.

[0036] In some embodiments of the present application, the polyurethane composite aerogel sheet has a porosity of 50-95%; for example, it can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%, etc. However, the present application is not limited to the listed values, and other unlisted values within this range are also applicable.

[0037] In some embodiments of the present application, the polyurethane composite aerogel sheet has a cell diameter of 10 nm-5 μm; for example, it can be 10 nm, 20 nm, 30 nm, 50 nm, 60 nm, 80 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2 μm, 2.2 μm, 2.5 μm, 2.8 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, or 5 μm, etc. However, the present application is not limited to the listed values, and other unlisted values within this range are also applicable.

[0038] In some embodiments of the present application, the polyurethane composite aerogel sheet has a water contact angle of the surface of ≥140°; for example, it can be 140°, 145°, 150°, 160°, 165°, or 170°, etc.

[0039] In some embodiments of the present application, the polyurethane composite aerogel sheet has a thickness of 0.3-20 mm; for example, it can be 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 12 mm, 13 mm, 15 mm, 16 mm, 18 mm, or 20 mm, etc. However, the present application is not limited to the listed values, and other unlisted values within this range are also applicable.

[0040] In a second aspect, the present application provides a method for preparing the polyurethane composite aerogel sheet as described in the first aspect, which comprises the following steps:

[0041] Mixing polyurethane, sheet-shaped micro-nano particles, spherical micro-nano particles, optionally a cell stabilizer, optionally a light stabilizer, and optionally an antioxidant with a first solvent to form a mixed solution;

[0042] Filling the mixed solution into an open container, and then performing solvent exchange by sinking into a second solvent to obtain a wet polyurethane composite aerogel;

[0043] drying the wet polyurethane composite aerogel to obtain the polyurethane composite aerogel sheet;

[0044] The first solvent comprises a good solvent for polyurethane, and optionally comprises a cosolvent and / or a poor solvent for polyurethane, and the content of the good solvent for polyurethane in the first solvent is greater than or equal to 85 vol% (for example, it can be 85 vol%, 86 vol%, 88 vol%, 90 vol%, 92 vol%, 93 vol%, 95 vol%, 96 vol%, 98 vol% or 100 vol%, etc.).

[0045] The second solvent is a poor solvent for polyurethane.

[0046] It should be noted that "optionally" in the present application means that there can be or there can not be. For example, the "optional cell stabilizer" means that there can be a cell stabilizer or there can not be a cell stabilizer. Whether to add this component in the preparation method depends on whether the polyurethane composite aerogel sheet to be prepared contains this component.

[0047] The preparation method provided by the present application has simple process, low equipment requirement, strong stability, high capacity and efficiency, and the polyurethane composite aerogel sheet prepared has smooth and compact surface (macroscopically), stable internal cell structure, and uniform size and distribution.

[0048] In the present application, the open container is not specially limited and can be routinely selected by those skilled in the art. For example, the open container can be a tray.

[0049] In the present application, the good solvent for polyurethane in the first solvent is used to dissolve polyurethane, and the content is controlled to be greater than or equal to 85 vol% to ensure that the mixed solution can reach a sufficient concentration to form the polyurethane composite aerogel sheet. When the first solvent is all a good solvent for polyurethane, it helps to improve the uniformity and stability of the cells in the polyurethane composite aerogel sheet. The cosolvent can be used to adjust the solubility parameter of the solvent system and promote the dissolution of polyurethane. When the first solvent contains a certain amount of a poor solvent for polyurethane, the size of the cells in the polyurethane composite aerogel sheet can be adjusted.

[0050] In some embodiments of the present application, the content of polyurethane in the mixed solution is 5-35 wt%, for example, it can be 5 wt%, 6 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt%, 28 wt%, 30 wt%, 32 wt% or 35 wt%, etc.; preferably 10-30%.

[0051] In the present application, the content of polyurethane in the mixed solution is controlled within the above range, which is helpful to obtain polyurethane composite aerogel sheet with more stable and uniform cell structure. If the content of polyurethane in the mixed solution is too low, the aerogel sheet is difficult to form; if the content of polyurethane in the mixed solution is too high, on the one hand, the polyurethane is not easy to dissolve, on the other hand, the viscosity of the mixed solution is large, which is easy to lead to lower porosity of the polyurethane composite aerogel sheet and non-uniform cell structure.

[0052] In some embodiments of the present application, the good solvent of the polyurethane is selected from one or more of N,N dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, acetone, butanone, cyclohexanone, isophorone, tetrahydrofuran and 1,4-dioxane.

[0053] In some embodiments of the present application, the cosolvent is selected from one or more of ethyl acetate, butyl acetate and isopropyl acetate.

[0054] In some embodiments of the present application, the poor solvent of the polyurethane is each independently selected from one or more of water, methanol, ethanol, isopropanol and butanol.

[0055] In some embodiments of the present application, in the step of loading the mixed solution into the open container, the liquid level of the mixed solution is 0.5-50 mm; for example, it can be 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm or 50 mm, etc. However, the present application is not limited to the listed values, and other unlisted values within the range are also applicable.

[0056] In the present application, the liquid level of the mixed solution is controlled within the above range, which is helpful to obtain polyurethane composite aerogel sheet with more stable and uniform cell structure. If the liquid level of the mixed solution is too large, on the one hand, it is easy to lead to unstable cell structure in the central region of the polyurethane composite aerogel sheet, and there may be broken holes, uneven hole size and uneven distribution (for example, there are dense regions inside); on the other hand, it will make the processing time longer and reduce the production efficiency. If the liquid level of the mixed solution is too small, on the one hand, it is easy to lead to unstable cell structure in the surface layer of the polyurethane composite aerogel sheet, and the surface is easy to have broken holes and pits; on the other hand, the formed polyurethane composite aerogel sheet is too thin, and its light reflectivity is low.

[0057] In some embodiments of the present application, the temperature for the solvent exchange is in the range of -20 to 70℃, for example, it can be -20℃, -15℃, -10℃, -5℃, 0℃, 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, 40℃, 50℃, 60℃ or 70℃, etc. The time for the solvent exchange is in the range of 0.5 to 6h, for example, it can be 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h or 6h, etc. However, the present application is not limited to the listed values, and other values not listed in the range are also applicable.

[0058] As understood by those skilled in the art, since the second solvent should be in liquid state during the solvent exchange, the temperature for the solvent exchange should also be higher than the freezing point and lower than the boiling point of the second solvent. For example, when the second solvent is water, the temperature for the solvent exchange is in the range of 0 to 70℃ (0℃ not included); when the second solvent is methanol, the temperature for the solvent exchange is in the range of -20 to 64.7℃ (64.7℃ not included).

[0059] In the present application, the temperature for the solvent exchange is controlled in the above range, which is helpful to obtain polyurethane composite aerogel sheet with more stable and uniform cell structure. If the temperature for the solvent exchange is too high, it can lead to unstable cell structure, uneven and large cell size, and surface defects of the polyurethane composite aerogel sheet. If the temperature for the solvent exchange is too low, the solvent exchange rate is too slow, which can reduce the production efficiency and make the cell wall thickness of the polyurethane composite aerogel sheet uneven.

[0060] In some embodiments of the present application, the second solvent comprises water, and the content of water in the second solvent is above 50vol%. For example, it can be 50vol%, 55vol%, 60vol%, 65vol%, 70vol%, 75vol%, 80vol%, 85vol%, 90vol%, 95vol% or 100vol%, etc. However, the present application is not limited to the listed values, and other values not listed in the range are also applicable.

[0061] In some embodiments of the present application, the second solvent comprises water, and optionally one or more of methanol, ethanol, isopropanol and butanol; and the content of water in the second solvent is above 50vol%.

[0062] In the present application, the content of water in the second solvent is controlled to be above 50vol%, which is helpful to further improve the stability and uniformity of the cell structure inside the polyurethane composite aerogel sheet and reduce defects, and also can reduce the cost and be more environmentally friendly.

[0063] In some embodiments of the present application, the drying method is air drying at room temperature.

[0064] In some embodiments of the present application, the air speed during air drying is 0.1-5 m / s; for example, it can be 0.1 m / s, 0.2 m / s, 0.3 m / s, 0.5 m / s, 0.8 m / s, 1 m / s, 1.5 m / s, 2 m / s, 2.5 m / s, 3 m / s, 3.5 m / s, 4 m / s, 4.5 m / s or 5 m / s, etc. However, the present application is not limited to the listed values, and other unlisted values within the range are also applicable.

[0065] In a third aspect, the present application provides a polyurethane composite aerogel sheet as described in the first aspect or prepared by the preparation method of the second aspect, for use as a building waterproof thermal insulation material.

[0066] Compared with the prior art, the present application has the following beneficial effects:

[0067] The polyurethane composite aerogel sheet provided by the present application has good ability to reflect sunlight and emit thermal radiation through the synergistic cooperation of the material and structure, and the surface hydrophobicity is improved. This enables the polyurethane composite aerogel sheet to achieve the effect of "no energy consumption refrigeration", and the slight damage to the surface does not significantly affect the waterproof effect, and the polyurethane composite aerogel sheet also has a self-cleaning function.

[0068] The preparation method provided by the present application has simple process, low equipment requirement, strong stability, high capacity and efficiency, and the polyurethane composite aerogel sheet prepared by the method has a smooth and compact surface (macroscopically), and the internal pore structure is stable, uniform and evenly distributed. DETAILED DESCRIPTION

[0069] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the specific embodiments are only used to help understand the present application, and should not be regarded as a specific limitation on the present application.

[0070] The sources of some raw materials used in the embodiments of the present application are as follows:

[0071] Polyurethane, grade 1175A, 1185A: purchased from BASF, Germany;

[0072] Polyurethane, grade 2363-80A: purchased from Dow Chemical, USA;

[0073] Boron nitride nanosheet: purchased from Xianfeng Nanometer Co., Ltd., visible light refractive index 2.1, sheet thickness 10-1000 nm, sheet diameter 1-50 μm;

[0074] Zinc oxide nanoplatelets: purchased from Xianfeng Nanometer Co., Ltd., visible light refractive index 1.5, platelet thickness 10-1000 nm, platelet diameter 1-10 pm;

[0075] Montmorillonite: purchased from Fenghong New Material Co., Ltd., visible light refractive index 1.4, platelet thickness 10-25 nm, platelet diameter 1-100 pm;

[0076] Hydrophobic silicon dioxide (spherical): purchased from Chuangying Technology Co., Ltd., D 90 Particle size 10-100 nm, visible light refractive index 1.45, water contact angle 151.6°;

[0077] Hydrophobic zinc oxide (spherical): purchased from Daxi Cong Co., Ltd., D 90 Particle size 10-100 nm, visible light refractive index 1.5, water contact angle 146.1°;

[0078] Hydrophobic titanium dioxide (spherical): purchased from Daxi Cong Co., Ltd., D 90 Particle size 10-100 nm, visible light refractive index 2.6, water contact angle 149.5°;

[0079] Example 1

[0080] The present example provides a polyurethane composite aerogel sheet having a structure of dense surface and porous interior; the components of the polyurethane composite aerogel sheet include, in parts by weight, polyurethane (1185A) 100 parts, boron nitride nanoplatelets 10 parts, hydrophobic silicon dioxide 20 parts, cell stabilizer DC-193, 2 parts, light stabilizer Tinuvin 292, 0.3 parts, and antioxidant 1076, 0.5 parts.

[0081] The preparation method of the polyurethane composite aerogel sheet in the present example is as follows:

[0082] (1) The polyurethane, boron nitride nanoplatelets, hydrophobic silicon dioxide, cell stabilizer DC-193, light stabilizer Tinuvin 292, and antioxidant 1076 are added in proportion to N,N dimethylformamide, stirred at 200 r / min and room temperature for 3 h to prepare a mixed solution with a polyurethane concentration of 25wt%;

[0083] (2) Pour the mixed solution into a tray with a size of 1m x 1m, with a liquid level of 10 mm. After the mixed solution in the tray is stable (ensuring a smooth liquid surface without bubbles), vertically and slowly immerse the tray into 23℃ water for solvent exchange. After 2 h, take out the wet polyurethane composite aerogel;

[0084] (3) The wet polyurethane composite aerogel is placed in a ventilated environment at room temperature for air drying to obtain a polyurethane composite aerogel sheet.

[0085] Example 2

[0086] The present example provides a polyurethane composite aerogel sheet, and the difference between the preparation method thereof and that of Example 1 is that the temperature of the water in step (2) is 40°C.

[0087] Example 3

[0088] The present example provides a polyurethane composite aerogel sheet, and the difference between the preparation method thereof and that of Example 1 is that the raw material ratio is: polyurethane 100 parts, boron nitride nanosheet 15 parts, hydrophobic silicon dioxide 15 parts, cell stabilizer DC-193, 2 parts, light stabilizer Tinuvin 292, 0.3 parts, and antioxidant 1076, 0.5 parts.

[0089] Example 4

[0090] The present example provides a polyurethane composite aerogel sheet, and the difference between the preparation method thereof and that of Example 1 is that in step (1) N,N dimethylformamide is replaced by a mixed solvent of acetone and water (volume ratio 92:8); and the water in step (2) is replaced by ethanol.

[0091] Example 5

[0092] The present example provides a polyurethane composite aerogel sheet, and the difference between the preparation method thereof and that of Example 1 is that the raw material ratio is: polyurethane 100 parts, boron nitride nanosheet 10 parts, and hydrophobic silicon dioxide 20 parts.

[0093] Example 6

[0094] The present example provides a polyurethane composite aerogel sheet, and the difference between the preparation method thereof and that of Example 1 is that the liquid level in step (2) is 5 mm.

[0095] Example 7

[0096] The present example provides a polyurethane composite aerogel sheet, and the difference between the preparation method thereof and that of Example 1 is that the liquid level in step (2) is 40 mm.

[0097] Example 8

[0098] The present example provides a polyurethane composite aerogel sheet, and the difference between the preparation method thereof and that of Example 1 is that the liquid level in step (2) is 80 mm.

[0099] Example 9

[0100] The embodiment provides a polyurethane composite aerogel sheet, which has a structure of dense surface and porous interior; ingredients of the polyurethane composite aerogel sheet include, in parts by weight, polyurethane (2363-80A) 100 parts, zinc oxide nanosheet 5 parts, hydrophobic zinc oxide 10 parts, cell stabilizer DC-193 2 parts, light stabilizer Tinuvin 292 0.3 parts and antioxidant 1076 0.5 parts.

[0101] The preparation method of the polyurethane composite aerogel sheet in the embodiment is as follows:

[0102] (1) polyurethane, zinc oxide nanosheet, hydrophobic zinc oxide, cell stabilizer DC-193, light stabilizer Tinuvin 292 and antioxidant 1076 are added into acetone in a proportioning manner, stirred at 200 r / min under normal temperature conditions for 3 h, and a mixed solution with a polyurethane concentration of 20wt% is prepared;

[0103] (2) the mixed solution is poured into a tray with a size of 1m*1m, the liquid level is 10 mm, after the mixed solution in the tray is stable (ensure that the liquid surface is smooth and free of bubbles), the tray is vertically and slowly sunk into a mixed solvent of 70°C water and isopropyl alcohol (volume ratio 50:50) for solvent exchange, and the polyurethane composite aerogel is obtained after being kept for 2 h and taken out;

[0104] (3) the wet polyurethane composite aerogel is placed in a normal temperature and ventilated environment for air drying, and the polyurethane composite aerogel sheet is prepared.

[0105] Embodiment 10

[0106] The embodiment provides a polyurethane composite aerogel sheet, which has a structure of dense surface and porous interior; ingredients of the polyurethane composite aerogel sheet include, in parts by weight, polyurethane (1175A) 100 parts, zinc oxide nanosheet 10 parts, hydrophobic silicon dioxide 20 parts, cell stabilizer DC-193 2 parts, light stabilizer Tinuvin 292 0.3 parts and antioxidant 1076 0.5 parts.

[0107] The preparation method of the polyurethane composite aerogel sheet in the embodiment is as follows:

[0108] (1) polyurethane, zinc oxide nanosheet, hydrophobic silicon dioxide, cell stabilizer DC-193, light stabilizer Tinuvin 292 and antioxidant 1076 are added into a mixed solvent of dimethylformamide and cyclohexanone (volume ratio 90:10) in a proportioning manner, stirred at 200 r / min under normal temperature conditions for 3 h, and a mixed solution with a polyurethane concentration of 10wt% is prepared; N,N

[0109] ​(2) Pour the mixed solution into a tray with a size of 1 m x 1 m, and the liquid level is 10 mm. After the mixed solution in the tray is stable (ensure that the liquid surface is smooth and free of bubbles), the tray is slowly sunk vertically into a mixed solvent of 23℃ water and ethanol (volume ratio 80:20) for solvent exchange. After 2 hours, take it out to obtain a wet polyurethane composite aerogel;

[0110] (3) Place the wet polyurethane composite aerogel in a normal temperature and ventilated environment for air drying to obtain a polyurethane composite aerogel sheet.

[0111] Example 11

[0112] The example provides a polyurethane composite aerogel sheet with a structure of dense surface and porous interior. The components of the polyurethane composite aerogel sheet include, by weight fraction, polyurethane (1185A) 100 parts, montmorillonite nanosheet 15 parts, hydrophobic titanium dioxide 20 parts, cell stabilizer DC-193 2 parts, light stabilizer Tinuvin 292 0.3 parts, and antioxidant 1076 0.5 parts.

[0113] The preparation method of the polyurethane composite aerogel sheet in the example is as follows:

[0114] (1) Add polyurethane, montmorillonite nanosheet, hydrophobic titanium dioxide, cell stabilizer DC-193, light stabilizer Tinuvin 292, and antioxidant 1076 according to the ratio into dimethylformamide, and stir at 200 r / min and room temperature for 3 hours to prepare a mixed solution with a polyurethane concentration of 5wt%; N,N

[0115] (2) Pour the mixed solution into a tray with a size of 1 m x 1 m, and the liquid level is 10 mm. After the mixed solution in the tray is stable (ensure that the liquid surface is smooth and free of bubbles), the tray is slowly sunk vertically into a mixed solvent of 23℃ water and ethanol (volume ratio 80:20) for solvent exchange. After 2 hours, take it out to obtain a wet polyurethane composite aerogel;

[0116] (3) Place the wet polyurethane composite aerogel in a normal temperature and ventilated environment for air drying to obtain a polyurethane composite aerogel sheet.

[0117] Comparative Example 1

[0118] The comparative example provides a polyurethane composite aerogel sheet, and the preparation method thereof is different from that of Example 1 in that the raw material ratio is: polyurethane 100 parts, cell stabilizer DC-193 2 parts, light stabilizer Tinuvin 292 0.3 parts, and antioxidant 1076 0.5 parts.

[0119] Comparative Example 2 ​

[0120] The comparative example provides a polyurethane composite aerogel sheet, the preparation method of which is different from that of Example 1 in that the raw material ratio is: polyurethane 100 parts, hydrophobic silicon dioxide 20 parts, cell stabilizer DC-193, 2 parts, light stabilizer Tinuvin 292, 0.3 parts and antioxidant 1076, 0.5 parts.

[0121] Comparative Example 3

[0122] The comparative example provides a polyurethane composite aerogel sheet, the preparation method of which is different from that of Example 1 in that the raw material ratio is: polyurethane 100 parts, boron nitride nanosheet 10 parts, cell stabilizer DC-193, 2 parts, light stabilizer Tinuvin 292, 0.3 parts and antioxidant 1076, 0.5 parts.

[0123] Comparative Example 4

[0124] A commercially available waterproof and thermal insulation integrated roll (purchased from Membrane Youge) has a silver surface color, a thickness of 5 mm and a size of 1 m x 1 m.

[0125] Comparative Example 5

[0126] A commercially available waterproof and thermal insulation integrated roll (purchased from Membrane Youge) has a black surface color, a thickness of 5 mm and a size of 1 m x 1 m.

[0127] Performance test

[0128] The performance of the polyurethane composite aerogel sheets and waterproof and thermal insulation integrated rolls provided in the above examples and comparative examples is tested, and the testing method is as follows:

[0129] Solar reflectance: The solar reflectance is tested by using an ultraviolet-visible-near infrared spectrometer, the testing wavelength range is 0.2-2 μm, and a polytetrafluoroethylene plate is selected as a standard reference.

[0130] 8-13 μm atmospheric window emissivity: The infrared emissivity of the material is tested by using a Fourier transform infrared spectrometer with a gold integrating sphere accessory, and the testing wavelength range is 2.5-25 μm.

[0131] Thermal conductivity: The thermal conductivity of the material is tested by using a hot-disk thermal constant analyzer.

[0132] Water contact angle: The water contact angle of the material is tested by using a contact angle tester, and the volume of the water droplet is selected to be 4 μL.

[0133] Average pore size: The average pore size is measured, counted by using SEM, and analyzed by using Image-J Pro for pore size distribution.

[0134] Porosity: The porosity is tested by using a mercury porosimeter.

[0135] Tensile strength, elongation at break: the tensile properties were tested by using a universal tensile testing machine, the sensor was selected as 2kN, the gauge length was 25mm, and the tensile speed was 100mm / min.

[0136] The results of the above performance tests are shown in Table 1 and Table 2.

[0137] Table 1

[0138]

[0139] Table 2

[0140]

[0141] From the test results in Table 1 and Table 2, it can be seen that the polyurethane composite aerogel sheet provided by the embodiment of the present application has a high solar reflectance, a high atmospheric window emissivity, a low thermal conductivity, and a large water contact angle, indicating that it has good heat insulation and waterproof properties.

[0142] Among them, compared with Example 1, Comparative Example 1 does not contain sheet-shaped micro-nano particles and spherical micro-nano particles, Comparative Example 2 does not contain sheet-shaped micro-nano particles, and Comparative Example 3 does not contain spherical micro-nano particles. The solar reflectance and atmospheric window emissivity of the polyurethane composite aerogel sheet provided by Example 1 are higher than those of Comparative Examples 1-3, and the water contact angle is much larger than that of Comparative Examples 1-3, indicating that the sheet-shaped micro-nano particles and the spherical micro-nano particles in the present application play a synergistic role in improving the ability of the aerogel sheet to reflect sunlight, emit thermal radiation, and hydrophobicity.

[0143] The above description is merely a specific implementation of the present disclosure, enabling those skilled in the art to understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to these embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A polyurethane composite aerogel sheet, characterized by, The polyurethane composite aerogel sheet has a surface dense and internal porous structure. The polyurethane composite aerogel sheet comprises, in parts by weight: 100 parts of polyurethane, 5-15 parts of sheet-shaped micro-nano particles, and 10-20 parts of spherical micro-nano particles; The polyurethane composite aerogel sheet has a porosity of 50-95%; The sheet-shaped micro-nano particles have a visible light refractive index of ≥1.4, a sheet layer thickness of ≤5 μm, and a sheet layer diameter of 0.5-100 μm; D of the spherical micro-nanoparticles 90 having a particle size of 10 nm to 3 μm, a visible light refractive index of the spherical micro-nanoparticles ≥ 1.4, and a water contact angle of the spherical micro-nanoparticles ≥ 130°; The polyurethane composite aerogel sheet is prepared by the following steps: Mixing polyurethane, sheet-shaped micro-nano particles, spherical micro-nano particles, optionally a cell stabilizer, optionally a light stabilizer, and optionally an antioxidant with a first solvent to form a mixed solution; The mixed solution is loaded into an open container and then immersed in a second solvent for solvent exchange to obtain a wet polyurethane composite aerogel; The wet polyurethane composite aerogel is dried to obtain the polyurethane composite aerogel sheet; The first solvent comprises a good solvent for polyurethane, optionally a cosolvent and / or a poor solvent for polyurethane, and the content of the good solvent for polyurethane in the first solvent is ≥85 vol%; The second solvent is a poor solvent for polyurethane.

2. The polyurethane composite aerogel sheet of claim 1, wherein, The sheet-shaped micro-nano particles are selected from one or more of boron nitride, zinc oxide, cerium fluoride, montmorillonite, and clay.

3. The polyurethane composite aerogel sheet of claim 1, wherein, The spherical micro-nano particles are selected from one or more of hydrophobic silica, hydrophobic zinc oxide, hydrophobic titanium dioxide, hydrophobic calcium titanate, and hydrophobic calcium carbonate.

4. The polyurethane composite aerogel sheet of claim 1, wherein, The polyurethane composite aerogel sheet further comprises one or more of the following ingredients in parts by weight: 1-3 parts of a cell stabilizer, 0.3-0.5 parts of a light stabilizer, and 0.1-0.5 parts of an antioxidant.

5. The polyurethane composite aerogel sheet of any of claims 1-4, wherein, The polyurethane composite aerogel sheet has a cell diameter of 10 nm-5 μm; And / or, the polyurethane composite aerogel sheet has a water contact angle of ≥140° on the surface thereof; And / or, the polyurethane composite aerogel sheet has a thickness of 0.3-20 mm.

6. A method of making a polyurethane composite aerogel sheet according to any one of claims 1-5, characterized in that, The preparation method comprises the following steps: Mixing polyurethane, sheet-shaped micro-nano particles, spherical micro-nano particles, optionally a cell stabilizer, optionally a light stabilizer, and optionally an antioxidant with a first solvent to form a mixed solution; The mixed solution is loaded into an open container and then immersed in a second solvent for solvent exchange to obtain a wet polyurethane composite aerogel; The wet polyurethane composite aerogel is dried to obtain the polyurethane composite aerogel sheet; The first solvent comprises a good solvent for polyurethane, optionally a cosolvent and / or a poor solvent for polyurethane, and the content of the good solvent for polyurethane in the first solvent is ≥85 vol%; The second solvent is a poor solvent for polyurethane.

7. The preparation method according to claim 6, characterized in that, The content of polyurethane in the mixed solution is 5-35 wt%; and / or the good solvent for the polyurethane is selected from N,N - one or more of dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, acetone, butanone, cyclohexanone, isophorone, tetrahydrofuran and 1,4-dioxane; And / or, the cosolvent is selected from one or more of ethyl acetate, butyl acetate, and isopropyl acetate; And / or, the poor solvents for polyurethane are each independently selected from one or more of water, methanol, ethanol, isopropanol, and butanol; And / or, in the step of loading the mixed solution into an open container, the liquid level of the mixed solution is 0.5-50 mm; And / or, the temperature of the solvent exchange is -20-70℃, and the time of the solvent exchange is 0.5-6 h; And / or, the drying method is air drying at room temperature.

8. The preparation method according to claim 7, characterized in that, The second solvent comprises water, and the content of water in the second solvent is 50 vol% or more; And / or, the air speed during the air drying is 0.1-5 m / s.

9. The polyurethane composite aerogel sheet according to any one of claims 1-5, or the polyurethane composite aerogel sheet prepared by the preparation method according to any one of claims 6-8, for use as a building waterproof thermal insulation material.

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