Silicon dioxide aerogel composite non-woven fabric heat insulation sheet

Abstract

The invention discloses a silicon dioxide aerogel composite non-woven fabric heat insulation sheet, which is characterized in that the silicon dioxide aerogel composite non-woven fabric heat insulation sheet comprises a non-woven fabric and silicon dioxide aerogel. The non-woven fabric comprises fibers and an adhesive bonding the fibers together, and the adhesive has hydroxyl. The silicon dioxide aerogel is compounded on the non-woven fabric. The silicon dioxide aerogel composite non-woven fabric heat insulation sheet is obtained through a sol preparation process, a gel base material compounding process, a gel reaction process and a drying process. Wherein the sol preparation process comprises the following steps: uniformly mixing and stirring a catalyst, a solvent and a silicon source, heating and refluxing at a first preset temperature for a first preset time, cooling, adding a gel accelerator, and uniformly mixing to form a sol precursor; the gel base material compounding process comprises the step of compounding the sol precursor into the non-woven fabric. The gel reaction process comprises the step of carrying out gel aging on the non-woven fabric compounded with the sol precursor at a second preset temperature for a second preset time.

Description

Technical Field

[0001] The present application relates to the technical field of composite materials, and in particular to a silica aerogel composite non-woven fabric thermal insulation sheet. Background Art

[0002] Aerogel is a material with extremely low density, which can be as low as 3kg / m 3 It also has a unique three-dimensional nano-network structure, a large specific surface area and a high porosity. Therefore, aerogel has excellent thermal insulation properties and is currently recognized as the solid material with the lowest thermal conductivity, with broad application prospects.

[0003] For example, by utilizing the thermal insulation properties of aerogel, aerogel is compounded with fiber felt to form a thermal insulation pad, which has a wide range of applications in fields such as aviation.

[0004] However, there are many problems in the preparation of thermal insulation pads. For example, as an inorganic chemical, silica aerogel is difficult to bond to the substrate with an organic adhesive. Therefore, the powder loss problem of silica aerogel composite thermal insulation pads has always been a pain point in the industry.

[0005] Therefore, a silica aerogel composite non-woven insulation sheet is needed to at least partially solve the above problems. Summary of the invention

[0006] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description of the Invention section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0007] In order to at least partially solve the above problems, the present application provides a silica aerogel composite non-woven insulation sheet, wherein the silica aerogel composite non-woven insulation sheet comprises:

[0008] A nonwoven fabric, comprising fibers and a binder for bonding the fibers together, wherein the binder has a hydroxyl group;

[0009] Silica aerogel, wherein the silica aerogel is composited on the non-woven fabric;

[0010] The silica aerogel composite non-woven fabric heat-insulating sheet is obtained through a sol preparation process, a gel substrate composite process, a gel reaction process and a drying process.

[0011] The sol preparation process includes: mixing and stirring the catalyst, solvent and silicon source uniformly, heating and refluxing at a first preset temperature for a first preset time, and then adding a gel accelerator after cooling and mixing uniformly to form a sol precursor.

[0012] The gel substrate composite process includes: compounding the sol precursor into the non-woven fabric,

[0013] The gel reaction process includes: allowing the non-woven fabric compounded with the sol precursor to gel at a second preset temperature for a second preset time.

[0014] According to the silica aerogel composite non-woven fabric thermal insulation sheet of the present application, the adhesive of the non-woven fabric contains hydroxyl groups which can reduce the powder loss rate of the product.

[0015] Optionally, the adhesive contains polyvinyl alcohol; and / or

[0016] The adhesive contains a reaction product of polyacrylic acid and polyol. According to the above configuration, the adhesive of the non-woven fabric contains polyvinyl alcohol and / or a reaction product of polyacrylic acid and polyol, which can effectively reduce the powder loss rate of the product.

[0017] Optionally, the binder is polyvinyl alcohol.

[0018] According to the above settings, PVA is selected as the adhesive for the non-woven fabric, which can significantly reduce the powder loss rate of the product under a wide range of conditions.

[0019] Optionally, the catalyst is hydrochloric acid, the solvent includes water and anhydrous ethanol, the silicon source is tetraethyl orthosilicate, and the gel accelerator is aqueous ammonia.

[0020] Optionally, the sol preparation process includes: mixing hydrochloric acid and anhydrous ethanol, adding tetraethyl orthosilicate and stirring for 2-5 minutes, heating the mixed solution to reflux at a temperature of 80-90°C for 3-5 hours, cooling to 15-25°C, adding ammonia water diluted with anhydrous ethanol and stirring for 15-25 minutes to obtain the sol precursor.

[0021] Optionally, the gel reaction process includes: allowing the non-woven fabric compounded with the sol precursor to gel at 30-40° C. for 20-28 hours.

[0022] Optionally, a solvent replacement process is further included between the gel reaction process and the drying process, and the solvent replacement process includes:

[0023] The gel-aged sheet is treated with anhydrous ethanol at 50-60° C. for 8-24 hours to completely replace the solvent with anhydrous ethanol.

[0024] Optionally, a hydrophobic modification process is further included between the gel reaction process and the solvent replacement process, and the hydrophobic modification process includes:

[0025] The gel-aged sheet is modified for 8 to 24 hours using a 20 to 30% volume fraction silane ethanol solution at 50 to 60°C.

[0026] Optionally, the drying process is CO2 supercritical drying.

[0027] Optionally, the drying process is carried out using a CO2 supercritical drying device having a drying kettle and a separation kettle, and the drying process includes:

[0028] The gel-aged sheet is placed in the drying kettle, and CO2 is introduced into the CO2 supercritical drying device at a flow rate of 35-40 L / h for 6-10 hours;

[0029] The temperature in the drying kettle is controlled to be 50-70°C, and the pressure in the drying kettle is controlled to be 17-18MPa, so that CO2 enters a supercritical state to replace ethanol in the gel-aged sheet;

[0030] The temperature in the separation kettle is controlled to be 30-50° C., and the pressure in the separation kettle is controlled to be 7-8 MPa, so that the CO2 and ethanol entering the separation kettle can be separated.

[0031] Optionally, the gel substrate composite process includes: pouring the sol precursor into the non-woven fabric through a pouring process.

[0032] Optionally, the mass proportion of the adhesive in the non-woven fabric is 5-30%.

[0033] Optionally, in the silica aerogel composite non-woven fabric thermal insulation sheet, the ratio of the mass of the silica aerogel to the mass of the non-woven fabric is 5%-60%.

[0034] Optionally, the silica aerogel composite non-woven insulation sheet has an air permeability of 1000-6000 mm / s.

[0035] Optionally, the silica aerogel composite non-woven fabric thermal insulation sheet has a powder loss rate of less than 1.5%.

[0036] Optionally, the thermal conductivity of the silica aerogel composite non-woven insulation sheet is less than 0.021 W / m·K.

[0037] Optionally, the thickness of the silica aerogel composite non-woven insulation sheet is 0.3-3 mm.

[0038] Optionally, the surface density of the silica aerogel composite non-woven insulation sheet is 30-300 g / m 2 .

[0039] The second aspect of the present application provides a silica aerogel composite non-woven insulation sheet, comprising:

[0040] A nonwoven fabric, comprising fibers and a binder for bonding the fibers together, wherein the binder has a hydroxyl group;

[0041] Silica aerogel, the silica aerogel is compounded on the non-woven fabric.

[0042] According to the silica aerogel composite non-woven fabric thermal insulation sheet of the present application, the adhesive of the non-woven fabric contains hydroxyl groups which can reduce the powder loss rate of the product.

[0043] Optionally, the adhesive contains polyvinyl alcohol; and / or

[0044] The adhesive contains a reaction product of polyacrylic acid and a polyol.

[0045] Optionally, the binder is polyvinyl alcohol.

[0046] Optionally, the mass proportion of the adhesive in the non-woven fabric is 5-30%.

[0047] Optionally, in the silica aerogel composite non-woven fabric thermal insulation sheet, the ratio of the mass of the silica aerogel to the mass of the non-woven fabric is 5%-60%.

[0048] Optionally, the silica aerogel composite non-woven insulation sheet has an air permeability of 1000-6000 mm / s.

[0049] Optionally, the silica aerogel composite non-woven fabric thermal insulation sheet has a powder loss rate of less than 1.5%.

[0050] Optionally, the thermal conductivity of the silica aerogel composite non-woven insulation sheet is less than 0.021 W / m·K.

[0051] Optionally, the thickness of the silica aerogel composite non-woven insulation sheet is 0.3-3 mm.

[0052] Optionally, the surface density of the silica aerogel composite non-woven insulation sheet is 30-300 g / m 2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The following drawings of the present application are used as a part of the present application for understanding the present application. The drawings show the embodiments of the present application and their descriptions, which are used to explain the principle of the present application.

[0054] In the attached figure:

[0055] Figure 1 A schematic diagram of the preparation process of a silica aerogel composite non-woven insulation sheet according to an embodiment of the present application; and

[0056] Figure 2 It is a schematic diagram of a supercritical drying device according to an embodiment of the present application. DETAILED DESCRIPTION

[0057] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present application. However, it is apparent to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some technical features well known in the art are not described.

[0058] It should be noted that the terms used here are only for describing specific embodiments, and are not intended to limit exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates that there are the features, wholes, steps, operations, elements, components and / or assemblies, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, assemblies, components and / or their combinations. It should be noted that the terms "upper", "lower", "front", "back", "left", "right", "inside", "outside" and similar expressions used herein are only for illustrative purposes, not for restriction.

[0059] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings.

[0060] The present application provides a silica aerogel composite non-woven fabric insulation sheet, which includes a non-woven fabric and a silica aerogel. The non-woven fabric includes fibers and an adhesive for bonding the fibers together, and the adhesive has a hydroxyl group. The silica aerogel is composited on the non-woven fabric. The silica aerogel composite non-woven fabric insulation sheet is obtained through a sol preparation process, a gel substrate composite process, a gel reaction process, and a drying process.

[0061] The sol preparation process includes mixing and stirring the catalyst, solvent and silicon source uniformly, heating and refluxing at a first preset temperature for a first preset time, and then adding a gel accelerator after cooling and mixing uniformly to form a sol precursor. The gel substrate composite process includes composite the sol precursor into a non-woven fabric. The gel reaction process includes gelling the non-woven fabric composited with the sol precursor at a second preset temperature for a second preset time.

[0062] According to the silica aerogel composite non-woven fabric thermal insulation sheet of the present application, the adhesive in the non-woven fabric contains hydroxyl groups, which greatly reduces the powder loss rate of the product.

[0063] As an implementation method, the adhesive may contain polyvinyl alcohol, which is a compound having a hydroxyl group. Alternatively, the adhesive may contain a reactant of polyacrylic acid and a polyol. Alternatively, the adhesive may contain polyvinyl alcohol and a reactant of polyacrylic acid and a polyol, that is, the adhesive may be a mixture containing the two.

[0064] Further preferably, the adhesive is polyvinyl alcohol, and the nonwoven fabric is a polyvinyl alcohol-based nonwoven fabric. Therefore, the silica aerogel composite nonwoven fabric insulation sheet in the present application can also be referred to as a silica aerogel composite polyvinyl alcohol-based nonwoven fabric insulation sheet.

[0065] PVA (polyvinyl alcohol) can be pure polyvinyl alcohol or industrial commercial polyvinyl alcohol. For example, it can be obtained by hydrolyzing polyvinyl acetate, and its main chemical structure is polyvinyl alcohol, but it contains a small amount of polyvinyl acetate monomer or a small amount of other monomers.

[0066] It is worth mentioning that the non-woven fabric described in the embodiment of the present application is a fiber mat formed without spinning and weaving, that is, non-woven fabric. Non-woven fabric is formed by directional or random arrangement of short fibers or long fibers to form a fiber mesh structure, and then reinforced by mechanical, thermal bonding or chemical methods. It does not have the warp and weft structure of woven fabric. The fibers can be glass fibers, carbon fibers, nylon fibers, polyester fibers, polyester fibers, polypropylene fibers or a mixture of several fibers.

[0067] The adhesive described in the embodiments of the present application refers to an adhesive used in non-woven fabrics to aggregate or bind long fibers and / or short fibers together in three-dimensional space through physical and / or chemical effects (such as intermolecular forces), i.e., "binder". It is not an adhesive used to form a "surface-to-surface" bonding relationship between bonding surfaces.

[0068] The specific preparation method of this application will be described in detail below. Figure 1The silica aerogel composite non-woven insulation sheet of the present application is obtained through a sol preparation process, a gel substrate composite process, a gel reaction process, a hydrophobic modification process, a solvent replacement process and a drying process in sequence.

[0069] In the sol preparation process, the catalyst is hydrochloric acid, the solvent includes water and anhydrous ethanol, the silicon source is tetraethyl orthosilicate, and the gel accelerator is ammonia water. The sol preparation process specifically includes: mixing hydrochloric acid and anhydrous ethanol, adding tetraethyl orthosilicate and stirring for 2-5 minutes, heating the mixed solution under reflux at a temperature of 80-90°C for 3-5 hours, cooling to 15-25°C, adding ammonia water diluted with anhydrous ethanol and stirring for 15-25 minutes, and obtaining a sol precursor.

[0070] The gel substrate composite process includes: infusing the sol precursor into the non-woven fabric through an infusion process. Preferably, the gel substrate composite process can be a vacuum infusion process.

[0071] The gel reaction process includes: making the non-woven fabric compounded with the sol precursor gel-age for 20-28 hours at 30-40°C.

[0072] The hydrophobic modification process comprises: modifying the gel-aged sheet material for 8 to 24 hours using 20 to 30% volume fraction of silane ethanol solution at 50 to 60°C.

[0073] The solvent replacement process includes: treating the gel-aged sheet with anhydrous ethanol at 50-60° C. for 8-24 hours to completely replace the solvent with anhydrous ethanol.

[0074] The drying process is preferably CO2 supercritical drying. Specifically, the drying process can be carried out using a CO2 supercritical drying device having a drying kettle and a separation kettle.

[0075] Furthermore, the drying process may include: placing the gel-aged sheet in a drying kettle, introducing CO2 into a CO2 supercritical drying device at a flow rate of 35-40L / h for 6-10h, wherein the temperature in the drying kettle is controlled to be 50-70°C, and the pressure in the drying kettle is controlled to be 17-18MPa, so that the CO2 enters a supercritical state to replace the ethanol in the gel-aged sheet, and the temperature in the separation kettle is controlled to be 30-50°C, and the pressure in the separation kettle is controlled to be 7-8MPa, so that the CO2 and ethanol entering the separation kettle can be separated.

[0076] Exemplarily, the drying process can be performed in Figure 2The process is carried out in the CO2 supercritical drying device shown in the figure. The CO2 gas cylinder provides the gas source for the storage tank, and the CO2 gas is transformed into a liquid state under the action of the refrigerator and enters the drying kettle under the action of the booster pump. Preferably, in order to fully dry the sheet, a secondary separation kettle is set to perform two separation steps.

[0077] The following will further explain this application in detail with reference to specific experimental steps:

[0078] The non-woven fabric substrate is cut into a suitable size and stacked into a desired thickness. For example, it can be cut into 25 cm × 25 cm sheets and stacked into a thickness of 0.7 cm to 1 cm. Different non-woven fabric substrates can be used as different embodiments. For example, the non-woven fabric substrate can be W125 (produced by Owens Corning, with a gram weight of 125 g / m 2 , single sheet thickness 1.11mm, adhesive contains PVA), YL-496 (produced by Owens Corning, gram weight 59.5g / m 2 , single sheet thickness 0.5mm, adhesive contains PVA), CX-59 (produced by Owens Corning, gram weight 46g / m 2 , single sheet thickness 0.4mm, adhesive contains PVA), Special NI (produced by Owens Corning, gram weight 37g / m 2 , single sheet thickness 0.34mm, adhesive contains PVA), C50A (produced by Owens Corning, weight 50g / m 2 , single sheet thickness 0.4mm, adhesive contains the reaction product of polyacrylic acid and polyol), C30A (produced by Owens Corning, gram weight 30g / m 2 , single sheet thickness 0.19mm, adhesive contains the reaction product of polyacrylic acid and polyol).

[0079] Prepare 0.1 mol / L hydrochloric acid, and mix 43g of the diluted hydrochloric acid with 2450g of anhydrous ethanol in a reactor. Then add 500g of tetraethyl orthosilicate to the reactor and stir for 3 minutes using a magnetic stirrer. After mixing evenly, heat the mixed solution at 85°C and reflux for 4h, wherein the temperature of the condenser is controlled at 5°C. Then cool the mixed solution to 20°C.

[0080] 2200 μL of 13 mol / L ammonia water was diluted with 40 g of anhydrous ethanol, and the diluted ammonia water was added to the above mixed solution at 20° C., and then stirred for 20 minutes to obtain a sol precursor.

[0081] Then, the sol precursor prepared in the above steps is infused into the cut non-woven fabric by vacuum infusion process. Then, the gel is aged at 35°C for 24 hours. Then, the gel-aged sheet is modified at 50-60°C using 20-30% volume fraction of methyltrimethoxysilane ethanol solution for 8-24 hours. Then, the gel-aged and hydrophobically modified sheet is treated with anhydrous ethanol at 50-60°C for 8-24 hours.

[0082] Then, the gel-aged sheet is placed in a drying kettle of a CO2 supercritical drying device, and CO2 is introduced into the CO2 supercritical drying device at a flow rate of 35-40L / h for 6-10 hours, wherein the temperature in the drying kettle is controlled to be 60°C, and the pressure in the drying kettle is controlled to be 17-18MPa. After all the ethanol in the sheet is replaced by supercritical CO2, the sheet is placed in a separation kettle, and the temperature in the separation kettle is controlled to be 40°C, and the pressure in the separation kettle is controlled to be 7.5MPa.

[0083] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0084] In Example 1, W125 was selected as the substrate, and an experiment of preparing a silica aerogel composite non-woven insulation sheet was carried out according to the above specific steps.

[0085] In Example 2, YL-496 was selected as the substrate, and an experiment of preparing a silica aerogel composite non-woven insulation sheet was carried out according to the above specific steps.

[0086] In Example 3, CX-59 was selected as the substrate, and an experiment of preparing a silica aerogel composite non-woven insulation sheet was carried out according to the above specific steps.

[0087] In Example 4, Special NI was selected as the substrate, and an experiment of preparing a silica aerogel composite non-woven fabric thermal insulation sheet was carried out according to the above specific steps.

[0088] In Example 5, C50A was selected as the substrate, and an experiment of preparing a silica aerogel composite non-woven insulation sheet was carried out according to the above specific steps.

[0089] In Example 6, C30A was selected as the substrate, and an experiment of preparing a silica aerogel composite non-woven insulation sheet was carried out according to the above specific steps.

[0090] In comparative example 1, C30A is selected as the substrate. The substrate is first soaked in a 0.1% PVA aqueous solution and then dried. Then, an experiment of preparing a silica aerogel composite non-woven insulation sheet is carried out according to the specific steps in the above embodiment.

[0091] In comparative example 2, C30A is selected as the substrate. The substrate is first soaked in a 0.5% PVA aqueous solution and then dried. Then, an experiment of preparing a silica aerogel composite non-woven fabric insulation sheet is carried out according to the specific steps in the above embodiment.

[0092] In comparative example 3, C30A is selected as the substrate. The substrate is first soaked in a 1.0% PVA aqueous solution and then dried. Then, an experiment of preparing a silica aerogel composite non-woven insulation sheet is carried out according to the specific steps in the above embodiment.

[0093] After the preparation of the silica aerogel composite non-woven insulation sheet is completed, it is weighed and placed in a sealed container, and then placed on an oscillating device for oscillation at a frequency of 1200 rpm for 10 minutes. After the completion, it is taken out and weighed again, and the powder loss rate is calculated.

[0094] Please refer to Table 1 for specific parameters and test results.

[0095] Table 1. Experimental comparison table of Examples 1-6 and Comparative Examples 1-3

[0096]

[0097]

[0098] Combined with the data of the above examples 1-5, both the PVA-based non-woven fabric and the polyacrylic acid-based non-woven fabric can achieve a good effect of reducing the powder loss rate.

[0099] And generally speaking, for non-woven fabrics, high air permeability means high porosity, and low air permeability means low porosity. In the actual use experience of silica aerogel composite non-woven insulation sheet, the higher the porosity, the sparser the fibers of the non-woven fabric, and the weaker its ability to carry silica aerogel particles, which leads to a higher powder loss rate.

[0100] However, combined with the data of Examples 1-4 and 5-6, it can be seen that the PVA-based nonwoven fabric can also have good powder loss rate data when the air permeability changes. The powder loss rate of the polyacrylic acid-based nonwoven fabric is affected by the air permeability: the powder loss rate of C30A with high air permeability is significantly higher than that of C50A with low air permeability.

[0101] It can be seen that PVA-based nonwoven fabrics have a wider adaptability than other systems of nonwoven fabrics and are not affected by air permeability. This makes it possible for silica aerogel composite nonwoven insulation sheets prepared from various types of PVA-based nonwoven fabrics to overcome the problem of easy powdering of aerogel insulation sheets.

[0102] Combining Example 6 with Comparative Examples 1-3, it can be seen that even if a PVA adhesive is added to a non-PVA system non-woven fabric, the powder loss rate cannot be effectively reduced, but the powder loss rate is increased. It can be seen that when PVA is used as a skeleton adhesive (binder) to adhere the fibers together in all directions in space, it has a significant improvement in reducing the powder loss rate. On the contrary, when PVA is used as a surface adhesive (adhesive), it does not have a significant improvement in reducing the powder loss rate.

[0103] In the silica aerogel composite non-woven insulation sheet of the present application, the mass proportion of the adhesive in the non-woven fabric is 5%-30%, preferably 10%-17%. In the silica aerogel composite non-woven insulation sheet, the ratio of the mass of the silica aerogel to the mass of the non-woven fabric is 5%-60%, preferably 32.1%-35.9%.

[0104] The air permeability of the silica aerogel composite non-woven insulation sheet of the present application is 1000-6000mm / s, preferably 1340-5470mm / s. The powder loss rate of the silica aerogel composite non-woven insulation sheet is less than 1.5%, preferably less than 1.07%, more preferably less than 0.46%, and further preferably 0.39%-0.46%. The thermal conductivity of the silica aerogel composite non-woven insulation sheet is less than 0.021W / m·K, preferably less than 0.02082W / m·K, more preferably 0.01971-0.02082W / m·K. The thickness of a single sheet of the silica aerogel composite non-woven insulation sheet is 0.3-3mm. The surface density of the silica aerogel composite non-woven insulation sheet of the present application is 30-300g / m 2 .

[0105] The processes and steps described in all the above preferred embodiments are only examples. Unless adverse effects occur, various processing operations can be performed in a sequence different from the sequence of the above processes. The sequence of steps in the above processes can also be increased, merged or deleted according to actual needs.

[0106] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present application. The terms used herein are only for describing specific implementation purposes and are not intended to limit the present application. The features described herein in one embodiment may be applied to another embodiment individually or in combination with other features, unless the feature is not applicable or otherwise specified in the other embodiment.

[0107] The present application has been illustrated through the above-mentioned embodiments, but it should be understood that the above-mentioned embodiments are only for the purpose of example and explanation, and the present application is not limited to the above-mentioned embodiments. According to the teachings of the present application, more variations and modifications can be made, and these variations and modifications all fall within the scope of protection claimed by the present application.

Claims

1. A silica aerogel composite nonwoven insulation sheet, characterized in that: The silica aerogel composite non-woven fabric thermal insulation sheet comprises: A nonwoven fabric, comprising fibers and a binder for bonding the fibers together, wherein the binder has a hydroxyl group; Silica aerogel, wherein the silica aerogel is composited on the non-woven fabric; The silica aerogel composite non-woven fabric heat-insulating sheet is obtained through a sol preparation process, a gel substrate composite process, a gel reaction process and a drying process. The sol preparation process includes: mixing the catalyst, solvent and silicon source After mixing evenly, heat to reflux at a first preset temperature for a first preset time, and then add the condensate after cooling. The glue accelerator is mixed evenly to form a sol precursor. The gel substrate composite process comprises: compounding the sol precursor to the In weaving, The gel reaction process comprises: making the non-woven fabric compounded with the sol precursor in the second The gel is aged for a second preset time at the preset temperature.

2. The silica aerogel composite nonwoven insulation sheet according to claim 1, characterized in that: The adhesive contains polyvinyl alcohol; and / or The adhesive contains a reaction product of polyacrylic acid and a polyol.

3. The silica aerogel composite nonwoven insulation sheet according to claim 1, characterized in that: The binder is polyvinyl alcohol.

4. The silica aerogel composite nonwoven insulation sheet according to claim 1, characterized in that: The catalyst is hydrochloric acid, the solvent includes water and anhydrous ethanol, the silicon source is tetraethyl orthosilicate, and the gel accelerator is ammonia water.

5. The silica aerogel composite nonwoven insulation sheet according to claim 4, characterized in that: The sol preparation process includes: mixing hydrochloric acid and anhydrous ethanol, adding tetraethyl orthosilicate and stirring for 2-5 minutes, heating the mixed solution under reflux at a temperature of 80-90° C. for 3-5 hours, cooling to 15-25° C., adding ammonia water diluted with anhydrous ethanol and stirring for 15-25 minutes to obtain the sol precursor.

6. The silica aerogel composite nonwoven insulation sheet according to claim 1, characterized in that: The gel reaction process comprises: allowing the non-woven fabric compounded with the sol precursor to gel and age for 20-28 hours at 30-40°C.

7. The silica aerogel composite nonwoven insulation sheet according to any one of claims 1 to 6, characterized in that: A solvent replacement process is also included between the gel reaction process and the drying process, and the solvent replacement process includes: The gel-aged sheet is treated with anhydrous ethanol at 50-60° C. for 8-24 hours to completely replace the solvent with anhydrous ethanol.

8. The silica aerogel composite nonwoven insulation sheet according to claim 7, characterized in that: A hydrophobic modification process is also included between the gel reaction process and the solvent replacement process, and the hydrophobic modification process includes: The gel-aged sheet is modified for 8 to 24 hours using a 20 to 30% volume fraction silane ethanol solution at 50 to 60°C.

9. The silica aerogel composite nonwoven insulation sheet according to claim 7, characterized in that: The drying process is CO2 supercritical drying.

10. The silica aerogel composite nonwoven insulation sheet according to claim 9, characterized in that: The drying process is carried out using a CO2 supercritical drying device having a drying kettle and a separation kettle, and the drying process comprises: The gel-aged sheet is placed in the drying kettle, and CO2 is introduced into the CO2 supercritical drying device at a flow rate of 35-40 L / h for 6-10 hours; The temperature in the drying kettle is controlled to be 50-70°C, and the pressure in the drying kettle is controlled to be 17-18MPa, so that CO2 enters a supercritical state to replace ethanol in the gel-aged sheet; The temperature in the separation kettle is controlled to be 30-50° C., and the pressure in the separation kettle is controlled to be 7-8 MPa, so that the CO2 and ethanol entering the separation kettle can be separated.

11. The silica aerogel composite nonwoven insulation sheet according to any one of claims 1 to 6, characterized in that: The gel substrate composite process comprises: pouring the sol precursor into the non-woven fabric through a pouring process.

12. The silica aerogel composite nonwoven insulation sheet according to any one of claims 1 to 6, characterized in that: The mass proportion of the adhesive in the non-woven fabric is 5-30%.

13. The silica aerogel composite nonwoven insulation sheet according to any one of claims 1 to 6, characterized in that: In the silica aerogel composite non-woven fabric thermal insulation sheet, the ratio of the mass of the silica aerogel to the mass of the non-woven fabric is 5%-60%.

14. The silica aerogel composite nonwoven insulation sheet according to any one of claims 1 to 6, characterized in that: The air permeability of the silica aerogel composite non-woven fabric thermal insulation sheet is 1000-6000 mm / s.

15. The silica aerogel composite nonwoven insulation sheet according to any one of claims 1 to 6, characterized in that: The powder loss rate of the silica aerogel composite non-woven fabric heat-insulating sheet is less than 1.5%.

16. The silica aerogel composite nonwoven insulation sheet according to any one of claims 1 to 6, characterized in that: The thermal conductivity of the silica aerogel composite non-woven fabric thermal insulation sheet is less than 0.021 W / m·K.

17. The silica aerogel composite nonwoven insulation sheet according to any one of claims 1 to 6, characterized in that: The thickness of the silica aerogel composite non-woven fabric thermal insulation sheet is 0.3-3 mm.

18. The silica aerogel composite nonwoven insulation sheet according to any one of claims 1 to 6, characterized in that: The surface density of the silica aerogel composite non-woven insulation sheet is 30-300 g / m 2 .

19. A silica aerogel composite nonwoven insulation sheet, characterized in that: The silica aerogel composite non-woven fabric thermal insulation sheet comprises: A nonwoven fabric, comprising fibers and a binder for bonding the fibers together, wherein the binder has a hydroxyl group; Silica aerogel, the silica aerogel is compounded on the non-woven fabric.

20. The silica aerogel composite nonwoven insulation sheet according to claim 19, characterized in that: The adhesive contains polyvinyl alcohol; and / or The adhesive contains a reaction product of polyacrylic acid and a polyol.

21. The silica aerogel composite nonwoven insulation sheet according to claim 20, characterized in that: The binder is polyvinyl alcohol.

22. The silica aerogel composite nonwoven insulation sheet according to any one of claims 19 to 21, characterized in that: The mass proportion of the adhesive in the non-woven fabric is 5-30%.

23. The silica aerogel composite nonwoven insulation sheet according to any one of claims 19 to 21, characterized in that: In the silica aerogel composite non-woven fabric thermal insulation sheet, the ratio of the mass of the silica aerogel to the mass of the non-woven fabric is 5%-60%.

24. The silica aerogel composite nonwoven insulation sheet according to any one of claims 19 to 21, characterized in that: The air permeability of the silica aerogel composite non-woven fabric thermal insulation sheet is 1000-6000 mm / s.

25. The silica aerogel composite nonwoven insulation sheet according to any one of claims 19 to 21, characterized in that: The powder loss rate of the silica aerogel composite non-woven fabric heat-insulating sheet is less than 1.5%.

26. The silica aerogel composite nonwoven insulation sheet according to any one of claims 19 to 21, characterized in that: The thermal conductivity of the silica aerogel composite non-woven fabric thermal insulation sheet is less than 0.021 W / m·K.

27. The silica aerogel composite nonwoven insulation sheet according to any one of claims 19 to 21, characterized in that: The thickness of the silica aerogel composite non-woven fabric thermal insulation sheet is 0.3-3 mm.

28. The silica aerogel composite nonwoven insulation sheet according to any one of claims 19 to 21, characterized in that: The surface density of the silica aerogel composite non-woven insulation sheet is 30-300 g / m 2 .

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