Waterborne polyurethane phase change aerogel glass and preparation method thereof

Abstract

The invention provides a preparation method of waterborne polyurethane phase change aerogel glass. The waterborne polyurethane phase change aerogel glass comprises a silicon dioxide aerogel heat insulation layer with a waterborne polyurethane phase change hydrophobic-hydrophilic double-layer structure. The aerogel glass is prepared through the steps of hydrophobic gel preparation, hydrophilic gel preparation, solvent replacement, supercritical drying, phase change material adsorption, packaging and the like. According to the prepared aerogel glass, the indoor temperature is actively adjusted through the waterborne polyurethane phase change process, the influence of the external temperature of a house on the indoor space is isolated through aerogel, the energy consumption needed by indoor heating and refrigerating is greatly reduced, and the phase change latent heat is absorbed or released through the waterborne polyurethane phase change material, so that the indoor heating and refrigerating efficiency is improved. And when the temperature difference inside and outside the building is large, a good heat-preservation and heat-insulation effect can be achieved. The polyurethane phase-change material and the aerogel are compounded, so that the overall thermal insulation performance is greatly improved, the comprehensive performance of the polyurethane phase-change aerogel glass is improved, and a new solution is provided for building energy conservation.

Description

Technical Field

[0001] The invention belongs to the technical field of aerogel glass, and particularly relates to a waterborne polyurethane phase-change aerogel glass and a preparation method thereof. Background Art

[0002] Building energy consumption mainly comes from energy consumption such as heating, air conditioning, ventilation, and hot water supply. Most buildings are high-energy-consuming and non-energy-saving; building energy conservation has become an important part of developing a conservation-oriented society and circular economy. It reduces energy consumption by rationally using energy and improving energy efficiency under the premise of ensuring building comfort. According to statistics and estimates of energy consumption of different types of buildings, nearly 50% of building energy is directly or indirectly caused by the external envelope structure. Therefore, studying the design and optimization of building envelope structures is the key to building energy conservation. However, due to the setting of fixed thermal physical parameters, it is difficult for traditional building envelope structures to achieve their own thermal balance according to indoor and outdoor temperatures and solar energy.

[0003] It has been found that applying phase change materials to building envelopes is more energy-efficient than ordinary buildings. Organic solid-liquid phase change materials have the advantages of a wide phase change temperature range, stable chemical properties, high latent heat, and low price, but their low thermal / electrical conductivity is not conducive to the use of solar energy; they need to be encapsulated or shaped, and there are problems such as edge leakage, volatilization or corrosion that limit their application; while solid-solid phase change materials are always in a solid state during the phase change process, and can absorb and release heat at the same time. As a new type of building envelope structure, the variable reflectivity building envelope structure integrating solid-solid phase change and porous ceramic heat storage can efficiently absorb and utilize solar energy in winter and effectively reduce solar radiation heat gain in summer, thereby achieving the purpose of reducing building energy consumption, and has important application significance.

[0004] In the technical system of the phase change aerogel glass industry, the two major fields of aerogel material technology and phase change material technology have shown remarkable development trends. In terms of aerogel material technology, the preparation technology of nanoporous structure aerogel has been paid attention to since 2018, aiming to develop new materials with excellent thermal insulation properties. Subsequently, the research and development of high-strength and high-transparency aerogels has also become a focus of attention, hoping to improve the mechanical properties and light transmittance of the material while maintaining excellent thermal insulation properties.

[0005] In terms of phase change material technology, the optimization of phase change cold storage materials and the modification of phase change heat storage materials are aimed at improving the energy storage efficiency and energy storage density of phase change materials. With the continuous development of technology, phase change intelligent temperature control materials can realize the function of actively adjusting temperature through the phase change process, and have broad application prospects in the fields of building energy conservation and electronic product heat dissipation. In general, the cross-integration of the two major technical fields of aerogel materials and phase change materials brings new development opportunities to the phase change aerogel glass industry and promotes technological progress in the fields of energy conservation, environmental protection, and new energy utilization.

[0006] In view of this, the present invention provides a method for preparing waterborne polyurethane phase change aerogel glass by compounding aerogel material, phase change material and glass, which can not only give the phase change aerogel good light transmittance, but also have other advantages of glass, such as weather resistance, mechanical strength, etc. The phase change aerogel glass of the present invention has broad application prospects in the field of construction, and is expected to play an important role in the fields of civil buildings, industrial plants, greenhouses, etc., improve the energy efficiency and comfort of buildings, and promote the development of green and environmentally friendly buildings. Summary of the invention

[0007] In order to overcome the deficiencies in the prior art, the main purpose of the present invention is to provide a water-based polyurethane phase change aerogel glass and a preparation method thereof. The water-based polyurethane phase change aerogel glass of the present invention combines the advantages of polyurethane, phase change materials and aerogels, and achieves heat absorption and release while having thermal insulation. It can efficiently absorb and utilize solar energy in winter and effectively isolate solar radiation heat in summer, thereby achieving the purpose of reducing building energy consumption.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is: A water-based polyurethane phase-change aerogel glass comprises an upper and lower glass plate, a hydrophobic aerogel layer and a hydrophilic aerogel layer loaded with a water-based polyurethane phase-change material, wherein the hydrophobic aerogel layer comprises a hydrophobic silica aerogel, and the hydrophilic aerogel layer loaded with a water-based polyurethane phase-change material consists of a hydrophilic silica aerogel and a water-based polyurethane solid-solid phase-change material.

[0009] The present invention also provides a method for preparing the waterborne polyurethane phase change aerogel glass, comprising the following steps: (1) Preparation of hydrophobic gel: Adding hydrophobic silica aerogel sol into a glass flat plate mold to cause a sol-gel reaction to obtain a first layer of transparent wet gel; (2) Preparation of hydrophilic gel: After the forming process, a hydrophilic silica aerogel sol is injected into the first layer of transparent wet gel in the mold to obtain a second layer of transparent wet gel; (3) solvent replacement: placing the transparent wet gel in the glass flat plate mold in an ethanol solution for solvent replacement to obtain an alcohol gel; (4) Supercritical drying: subjecting the above-mentioned glass plate mold loaded with alcohol gel to supercritical carbon dioxide drying to obtain a transparent silica aerogel glass plate; (5) Phase change material adsorption: adding an aqueous polyurethane emulsion dropwise to the hydrophilic silica aerogel of the transparent silica aerogel glass plate, drying and naturally cooling to obtain an aqueous polyurethane phase change aerogel glass concave plate containing an aqueous polyurethane solid-solid phase change material; (6) Packaging: The glass cover plate is bonded to the concave plate of the waterborne polyurethane phase change aerogel glass to obtain the waterborne polyurethane phase change aerogel glass.

[0010] In the above technical solution, in step (1), the sol-gel reaction temperature is 10 to 40° C., and the reaction time is 20 to 300 min; The sol is one or more of methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate, methyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane and their oligomers and partial hydrolysis products, ethanol, methanol, and hexadecyltrimethylammonium bromide.

[0011] In the above technical solution, in step (2), the sol-gel reaction temperature is 10 to 40° C., and the gel time is 20 to 300 min; The sol is one or more of ethyl orthosilicate, propyl orthosilicate, ethanol, methanol, acetic acid, ammonia water, sodium fluoride, ammonium fluoride and water.

[0012] In the above technical solution, in step (1) and step (2), the thickness of the transparent wet gel formed on the inner surface of the mold is 1 to 5 mm.

[0013] In the above technical solution, in step (3), the ethanol solution is a mixture of ethanol and water, and the mass ratio is 1: (0.01-0.6).

[0014] In the above technical solution, in step (4), the temperature of the supercritical carbon dioxide drying is 35-60° C., and the drying time is 6-24 hours.

[0015] In the above technical solution, in step (5), the drying temperature is 40-60° C. and the drying time is 7-9 hours.

[0016] In the above technical solution, the hydrophilic aerogel has a nano-scale porous structure and serves as a carrier of the aqueous polyurethane phase change material. The aqueous polyurethane solid-solid phase change material loaded therein adjusts the temperature by absorbing or releasing the phase change latent heat.

[0017] The aerogel glass of the present invention contains a water-based polyurethane energy storage phase change material, which can absorb or release heat within a specific temperature range. In addition, since water is used as a dispersion medium, it has the advantages of being environmentally friendly, safe, and easy to process, and has a wide range of applications in the field of building energy conservation.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The waterborne polyurethane phase-change aerogel glass of the present invention can actively adjust the indoor temperature through the phase change process, and can isolate the influence of the external temperature of the house on the indoor space through the silicon dioxide aerogel layer, thereby greatly reducing the energy consumption required for indoor heating and cooling. The hydrophilic aerogel layer is used as a carrier of the waterborne polyurethane phase-change material, and the waterborne polyurethane solid-solid phase-change material loaded therein adjusts the temperature by absorbing or releasing the phase-change latent heat. When the temperature difference between the inside and outside of the building is large, the glass can play a good role in thermal insulation, and can absorb and release heat at the same time. It can efficiently absorb and utilize solar energy in winter and effectively isolate solar radiation heat in summer, which has important application significance for reducing building energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 The waterborne polyurethane phase-change aerogel glass of the present invention; In the figure: an upper glass plate 1, a hydrophobic silica aerogel layer 2, a hydrophilic silica aerogel layer 3 loaded with an aqueous polyurethane solid-solid phase change material, a glass concave plate 4, and a lower glass plate 5; Figure 2 It is a schematic diagram of preparing the waterborne polyurethane phase change aerogel glass of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] like Figure 1 As shown, the aqueous polyurethane solid-solid phase change aerogel glass of the present invention comprises in sequence: an upper glass plate 1, a hydrophobic aerogel layer 2, a hydrophilic aerogel layer 3 loaded with an aqueous polyurethane solid-solid phase change material, a glass concave plate 4 and a lower glass plate 5; the hydrophobic aerogel layer 3 comprises a hydrophobic silica aerogel, and the hydrophilic aerogel layer loaded with an aqueous polyurethane solid-solid phase change material consists of a hydrophilic silica aerogel and an aqueous polyurethane solid-solid phase change material.

[0022] The aerogel glass of the present invention can actively adjust the indoor temperature through the phase change process, and the hydrophobic silica aerogel layer 2 can isolate the influence of the external temperature of the house on the indoor temperature, thereby greatly reducing the energy consumption required for indoor heating and cooling. The hydrophilic aerogel layer is used as a carrier 3 of the aqueous polyurethane phase change material, and the aqueous polyurethane solid-solid phase change material loaded therein can absorb or release the phase change latent heat to adjust the temperature; when the temperature difference between the inside and outside of the building is large, it can play a good role in heat preservation and heat insulation, and can realize heat absorption and release at the same time, can efficiently absorb and utilize solar energy in winter, and can effectively isolate solar radiation heat in summer, which has important application significance for reducing building energy consumption.

[0023] The technical solution of the present invention is described in detail below in conjunction with embodiments.

[0024] Embodiment 1: A waterborne polyurethane phase change aerogel glass comprises the following steps: (1) Preparation of hydrophobic gel: Add hydrophobic silica aerogel sol into a glass flat plate mold to cause a sol-gel reaction to obtain a first layer of transparent wet gel with a gel thickness of 5 mm; The hydrophobic silica aerogel is prepared as follows: 0.1 mol / L acetic acid is added to the sol to adjust the pH, and then the sol is hydrolyzed at 4-5 and 60°C for 8 hours, and then 0.3 mol / L sodium hydroxide is added to adjust the pH to 8-9 for gelation, wherein the sol is 60 parts of ethyl orthosilicate, 64 parts of methyltriethoxysilane, 4 parts of pure water, 100 parts of ethanol, and 0.6 parts of hexadecyltrimethylammonium bromide in molar parts. (2) Preparation of hydrophilic gel: After the hydrophobic gel is formed, a second layer of hydrophilic silica aerogel sol is injected onto the first layer of transparent wet gel in the mold to prepare a second layer of transparent wet gel, and the gel thickness is 5 mm; The sol is composed of 1 part of ethyl orthosilicate, 12 parts of pure water, 33 parts of ethanol, 0.12 parts of ammonia water, and 0.076 parts of sodium fluoride in molar proportions; (3) solvent replacement: placing the transparent wet gel in the glass flat plate mold in a mixed solution of ethanol and water in a mass ratio of 80:20 for solvent replacement to obtain an alcohol gel; (4) Supercritical drying: The glass plate mold loaded with the alcohol gel was placed in a drying kettle and dried with supercritical carbon dioxide at 50° C. for 8 h to obtain a transparent silica aerogel glass plate.

[0025] (5) Phase change material adsorption: Based on the volume of the second layer of hydrophilic silica aerogel, 2 g / cm 3The adsorption amount of the aqueous polyurethane emulsion was calculated based on the ratio, and the solution was added dropwise and adsorbed into the second hydrophilic silica aerogel layer of the transparent silica aerogel glass plate. The solution was then transferred to a constant temperature oven at 50°C for 8 hours, and finally taken out and naturally cooled to obtain a waterborne polyurethane phase change aerogel glass concave plate containing a waterborne polyurethane solid-solid phase change material.

[0026] (6) Packaging: Figure 1 The glass cover plate is attached to the waterborne polyurethane phase change aerogel glass concave plate to obtain the waterborne polyurethane phase change aerogel glass with a light transmittance of 85%.

[0027] Embodiment 2: (1) Preparation of hydrophobic gel: Adding hydrophobic silica aerogel sol into the glass flat plate mold to allow the sol to undergo a sol-gel reaction to obtain a transparent wet gel with a gel thickness of 3 mm; The preparation method of the hydrophobic silica aerogel sol comprises the following steps: adding 0.1 mol / L acetic acid to the sol to adjust the pH value, hydrolyzing the sol at 4-5 and 60° C. for 8 hours, and then adding 0.3 mol / L sodium hydroxide to adjust the pH value to 8-9 for gelation; wherein the sol comprises 48 parts of ethyl orthosilicate, 72 parts of phenyltriethoxysilane, 6 parts of pure water, 96 parts of ethanol, and 0.8 parts of hexadecyltrimethylammonium bromide in molar proportions; (2) Preparation of hydrophilic gel: After the first layer of transparent wet gel is formed, the sol of the second layer of hydrophilic silica aerogel is injected into the mold to obtain the second layer of transparent wet gel, and the thickness of the gel is 3 mm; The sol is composed of 3 parts of methyl orthosilicate, 12 parts of pure water, 35 parts of ethanol, 0.17 parts of ammonia water, and 0.04 parts of sodium fluoride in molar proportions; (3) solvent replacement: placing the transparent wet gel in the glass flat plate mold in a mixed solution of ethanol and water in a mass ratio of 80:20 for solvent replacement to obtain an alcohol gel; (4) Supercritical drying: The glass plate mold together with the alcohol gel is placed in a drying kettle at a temperature of 50° C. for 8 hours to perform supercritical carbon dioxide drying to obtain a transparent silica aerogel glass plate.

[0028] (5) Phase change material adsorption: According to the volume of the second layer of hydrophilic silica aerogel, the adsorption amount was calculated with a ratio of 2 g / cm3 of aqueous polyurethane emulsion, and the adsorbed material was added dropwise into the second layer of hydrophilic silica aerogel of the transparent silica aerogel glass plate, and then transferred to a constant temperature oven at 50°C for 8 hours. Finally, the plate was taken out and naturally cooled to obtain a waterborne polyurethane phase change aerogel glass concave plate containing a waterborne polyurethane solid-solid phase change material.

[0029] (6) Packaging: The glass cover plate is bonded to the waterborne polyurethane phase change aerogel glass concave plate to obtain the waterborne polyurethane phase change aerogel glass.

[0030] Embodiment 3: The same preparation method as in Example 1 was used, except that the gel thicknesses were 1 mm, 2 mm, 3 mm and 4 mm. The effect of different gel thicknesses on the transmittance of waterborne polyurethane phase change aerogel glass was investigated, and the results are shown in Table 1.

[0031] Table 1

[0032] It can be seen from Table 1 that as the aerogel thickness increases, the transmittance of the waterborne polyurethane phase change aerogel glass decreases. Therefore, the transmittance of the aerogel glass can be adjusted by selecting a suitable aerogel thickness.

[0033] Comparative Example 1: Comparative Example 1 is substantially the same as Example 1, except that the phase change material in step (5) is not added dropwise.

[0034] Comparative Example 2: Comparative Example 2 is substantially the same as Example 2, except that in step (3), the transparent wet gel in the glass flat plate mold is placed in a mixed solution of ethanol and water in a mass ratio of 20:80 for solvent replacement.

[0035] The performance of the aqueous polyurethane phase change aerogel glasses prepared in Examples 1-2 and Comparative Examples 1-2 was tested respectively, and the results are shown in Table 2.

[0036] Table 2 Performance test results of aerogel glasses prepared in Examples 1-2 and Comparative Examples 1-2

[0037] As can be seen from Table 2, the water-based polyurethane phase change aerogel glass of the present invention isolates the influence of the external temperature of the house on the indoor environment through the hydrophobic silica aerogel layer, and at the same time adsorbs the water-based polyurethane emulsion into the hydrophilic aerogel layer, and adjusts the temperature through the heat absorption or heat release of the water-based polyurethane solid-solid phase change material, thereby reducing the energy consumption of the building, and has broad application prospects in the field of construction.

[0038] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A waterborne polyurethane phase change aerogel glass, characterized in that: The aerogel glass comprises upper and lower glass plates, a hydrophobic aerogel layer and a hydrophilic aerogel layer loaded with an aqueous polyurethane phase change material, wherein the hydrophilic aerogel layer loaded with an aqueous polyurethane phase change material is composed of hydrophilic silicon dioxide aerogel and an aqueous polyurethane solid-solid phase change material.

2. The method for preparing the waterborne polyurethane phase change aerogel glass according to claim 1, characterized in that: The following steps are involved: (1) Preparation of hydrophobic gel: Adding hydrophobic silica aerogel sol into a glass flat plate mold to cause a sol-gel reaction to obtain a first layer of transparent wet gel; (2) Preparation of hydrophilic gel: After the forming process, a hydrophilic silica aerogel sol is injected into the first layer of transparent wet gel in the mold to obtain a second layer of transparent wet gel; (3) solvent replacement: placing the transparent wet gel in the glass flat plate mold in an ethanol solution for solvent replacement to obtain an alcohol gel; (4) Supercritical drying: subjecting the above-mentioned glass plate mold loaded with alcohol gel to supercritical carbon dioxide drying to obtain a transparent silica aerogel glass plate; (5) Phase change material adsorption: adding an aqueous polyurethane emulsion dropwise to the hydrophilic silica aerogel of the transparent silica aerogel glass plate, drying and naturally cooling to obtain an aqueous polyurethane phase change aerogel glass concave plate containing an aqueous polyurethane solid-solid phase change material; (6) Packaging: The glass cover plate is bonded to the concave plate of the waterborne polyurethane phase change aerogel glass to obtain the waterborne polyurethane phase change aerogel glass.

3. The method for preparing waterborne polyurethane phase change aerogel glass according to claim 2, characterized in that: In step (1), the temperature of the sol-gel reaction is 10 to 40° C., and the reaction time is 20 to 300 min; The sol is one or more of methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate, methyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane and their oligomers and partial hydrolysis products, ethanol, methanol, and hexadecyltrimethylammonium bromide.

4. The method for preparing waterborne polyurethane phase change aerogel glass according to claim 2, characterized in that: In step (2), the sol-gel reaction temperature is 10-40° C., and the gel time is 20-300 min; the sol is one or more of ethyl orthosilicate, propyl orthosilicate, ethanol, methanol, acetic acid, ammonia water, sodium fluoride, ammonium fluoride, and water.

5. The method for preparing waterborne polyurethane phase change aerogel glass according to claim 2, characterized in that: In the steps (1) and (2), the thickness of the transparent wet gel formed on the inner surface of the mold is 1 to 5 mm.

6. The method for preparing waterborne polyurethane phase change aerogel glass according to claim 2, characterized in that: In step (3), the ethanol solution is a mixture of ethanol and water in a mass ratio of 1:(0.01-0.6).

7. The method for preparing waterborne polyurethane phase change aerogel glass according to claim 2, characterized in that: In step (4), the supercritical carbon dioxide drying temperature is 35-60° C., and the drying time is 6-24 hours.

8. The method for preparing waterborne polyurethane phase change aerogel glass according to claim 2, characterized in that: In step (5), the drying temperature is 40-60° C. and the drying time is 7-9 hours.

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