Aerogel composite material and normal-pressure continuous production method thereof

Abstract

The invention relates to a normal-pressure continuous production method of an aerogel composite material, which comprises the continuous and uninterrupted assembly line steps of sol and polycondensation agent preparation, unwinding, hedging negative pressure impregnation, gel or gel thickness determination, aging, solvent replacement, normal-pressure microwave drying, hot air drying, winding and the like. By setting hedging negative pressure gum dipping, the gum dipping speed, the sol filling rate and the gum dipping uniformity are guaranteed, microwave treatment is introduced in the steps of aging, replacement, drying and the like, assembly line production can be carried out at a relatively high speed, production can be carried out under normal pressure, and the prepared product has the technical effects of being uniform and stable.

Description

Technical Field

[0001] The invention relates to the technical field of aerogels, and in particular to an aerogel composite material and a normal-pressure continuous production method thereof. Background Art

[0002] Aerogel has very high porosity and very large specific surface area, as well as low density and low thermal conductivity. At present, it is mainly used by compounding catalyzed sol with fiber felt, and then immersing the catalyzed sol into the fiber felt to form an aerogel composite material through gelation, replacement, and supercritical drying.

[0003] The existing production process for aerogel composite materials is intermittent, and it is rare to form a continuous production line as a whole. This is because its impregnation, aging, replacement, etc. all require a lot of time, so it is impossible to form a continuous production line. At the same time, the existing preparation process generally requires supercritical drying for drying, which generally requires a certain pressure setting and a long drying time. Therefore, long-term impregnation, aging, replacement and high-pressure treatment bring great difficulties to the production of continuous production lines.

[0004] Chinese invention patent publication CN109574622A discloses a method for preparing a high temperature resistant silica aerogel thermal insulation felt, wherein the silica aerogel thermal insulation felt is prepared by using industrial sodium silicate as raw material, fiber coupling, and then washing with warm water to remove impurities, continuous cycle replacement of solvent ethanol, and finally drying at normal pressure. However, in the preparation process, the fiber felt is placed in a mold and then sprayed with sol to compound the sol and the fiber felt, and it is also impossible to achieve production on a continuous production line. Summary of the invention

[0005] In view of the problems existing in the above-mentioned existing aerogel preparation process, the present invention proposes a preparation method for realizing the continuous production of aerogel composite materials at normal pressure while ensuring the performance and quality of the aerogel composite materials, specifically a normal pressure continuous production device for aerogel composite materials.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the device for continuous production of aerogel composite materials at normal pressure of the present invention is:

[0007] A method for continuous production of an aerogel composite material under normal pressure, comprising the following steps:

[0008] S1, prepare sol and condensation agent, add alkyl siloxane, water, alcohol and hydrolyzing agent into stirring tank I of solution mixing part to obtain first solution, add silica sol, water and quaternary ammonium salt compound into stirring tank II of solution mixing part to obtain second solution, add the second solution into stirring tank I of the prepared first solution to obtain sol.

[0009] Water and an alkaline substance are mixed and stirred to obtain a polycondensation agent.

[0010] S2, unwinding, unwinds the substrate coil by an unwinder, unfolds the substrate coil into a transmission component and moves forward continuously.

[0011] S3, counter-vacuum dipping, the sol and polycondensing agent prepared in step S1 are respectively introduced into the mixing chamber of the counter-vacuum dipping component through relatively arranged high-pressure input ports in a counter-vacuum manner for counter-vacuum mixing; then the counter-vacuum mixed catalytic sol is introduced through the output port of the mixing chamber onto the substrate unwound by the unwinder in step S2 and introduced into the counter-vacuum dipping component, and negative pressure is set in the lower space of the substrate, and the catalytic sol discharged from the output port of the mixing chamber onto the substrate is uniformly impregnated with the substrate by the negative pressure, so as to obtain a composite substrate containing the catalytic sol after dipping treatment.

[0012] S4, gel, continuously convey the composite substrate containing the catalytic sol after the dipping treatment in step S3 to the gel thickness setting device, and perform thickness setting and gelation operations on the composite substrate containing the catalytic sol by rolling and leveling the composite substrate containing the catalytic sol and setting the gap thickness during the rolling process.

[0013] S5, aging, the composite gel obtained after the gel treatment in step S4 is continuously transported to a microwave aging tunnel component, and microwave heating is performed on the composite gel in the microwave aging tunnel component to obtain an aged composite gel.

[0014] S6, solvent replacement, the aged composite gel obtained in step S5 is continuously transported to a replacement tunnel component provided with a microwave treatment device or an ultrasonic treatment device, and water in the composite gel is replaced by a replacement liquid.

[0015] S7, normal pressure microwave drying, the composite gel obtained after the solvent replacement treatment in step S6 is continuously conveyed to a microwave drying tunnel machine, the composite gel is subjected to microwave heating in the microwave drying tunnel machine, and a dried aerogel composite material is obtained.

[0016] S8, hot air drying, the aerogel composite material obtained after microwave drying in step S7 is continuously conveyed to a hot air drying tunnel machine, and is rapidly heated and dried by the hot air being at a non-parallel angle to the traveling direction of the continuously conveyed aerogel composite material.

[0017] S9, rolling up, winding the aerogel composite material obtained after hot air drying in step S8 into a roll by a rolling device to obtain an aerogel composite material product.

[0018] Steps S2 to S9 are continuous and uninterrupted assembly line production.

[0019] Preferably, step S4 is replaced by:

[0020] S4, gelation, continuously transferring the composite substrate containing the catalytic sol after the dipping treatment in step S3 to a gelation device, and performing gelation treatment on the composite substrate containing the catalytic sol by rolling and leveling the composite substrate containing the catalytic sol.

[0021] Preferably, in step S1, alkyl siloxane, water, alcohol solvent and hydrolyzing agent are mixed and stirred in stirring tank I for 4 to 6 hours to obtain a first solution, silica sol, water and quaternary ammonium salt compound are mixed and stirred in stirring tank II for 0.5 to 4 hours to obtain a second solution, and the second solution is added to the obtained first solution in stirring tank I and mixed and stirred for 0.2 to 2 hours to obtain a sol; the stirring time after the water and the alkali are mixed is 5 to 20 minutes.

[0022] Preferably, in step S3, the counter-mixing time is 2 to 20 seconds.

[0023] Preferably, in step S4, while the thickness determination operation is being performed, gelation is achieved within 0.5 to 5 minutes.

[0024] Preferably, in step S5, the temperature of microwave heating is controlled at 55-65° C., and the time of microwave aging is 21-60 min.

[0025] Preferably, in step S6, the temperature of microwave heating or ultrasonic heating performed by the microwave treatment device or ultrasonic treatment device is controlled at 55 to 65° C., and the cyclic replacement treatment time is 20 to 58 min.

[0026] Preferably, in step S7, the temperature of microwave heating is controlled at 65-120° C., and the microwave drying time is 20-60 min.

[0027] Preferably, in step S8, the hot air is at a perpendicular angle to the traveling direction of the aerogel composite material to perform rapid heating and drying treatment.

[0028] Preferably, in step S8, the hot air temperature is controlled to be 85-180° C., and the hot air drying treatment time is 18-62 min;

[0029] Preferably, in step S2, the unwinding forward speed is 3 to 10 m / min.

[0030] Preferably, in step S3, the sol is pumped into the mixing chamber by a plunger pump, and the pressure of the sol pumping is controlled to be 0.3-10 MPa, and the condensation agent is pumped into the mixing chamber by a plunger pump, and the pressure of the condensation agent pumping is controlled to be 0.5-11 MPa; the negative pressure of the space below the substrate is -5 to -70.0 kPa.

[0031] Preferably, in step S3, the discharge port of the mixing chamber is a glue coating head provided with a slit;

[0032] Preferably, in step S4, before rolling and leveling the composite substrate containing the catalytic sol, the composite substrate containing the catalytic sol is pre-gelled in a pre-gel box by heating with hot water, the temperature of the hot water heating is 35-45°C, and the gel thickness setting device controls the thickness of the composite gel to 0.5-15mm, with a thickness accuracy of ±0.15mm.

[0033] Preferably, a liquid-sealing device is provided between step S4 and step S5, between step S5 and step S6, between step S6 and step S7, and between step S7 and step S8, the interior of the liquid-sealing device is filled with liquid, and a vertical partition with its bottom immersed in the filled liquid is provided at the inner top of the liquid-sealing device, the composite gel or aerogel composite material is continuously transported into the liquid-sealing device from the inlet of the liquid-sealing device, enters into the liquid through one end of the vertical partition and passes through the liquid below the vertical partition under the conduction of the guide roller provided in the liquid-sealing device, then leaves the liquid from the other end of the vertical partition, and is continuously transported out through the outlet of the liquid-sealing device, so as to realize the sealed isolation of the gas between the discharge end and the discharge end through the liquid-sealing device; the liquid-sealing device or the inert gas sealing device is provided between step S8 and step S9, the inert gas sealing device is a sealing device in which the part through which the aerogel composite material passes is filled with inert gas and other gases are excluded.

[0034] Preferably, the liquid in the liquid-sealing device between step S4 and step S5, between step S5 and step S6, and between step S6 and step S7 is alcohol, and the liquid in the liquid-sealing device between step S7 and step S8 is water.

[0035] An aerogel composite material, wherein the aerogel composite material is prepared by the above-mentioned normal pressure continuous production method, wherein the aerogel composite material is a fiber aerogel composite material (including an inorganic fiber aerogel composite material, an organic fiber aerogel composite material), an organic foaming aerogel composite material, and the thermal conductivity of the aerogel composite material at room temperature is 0.016-0.021 W / m·k, and the specific surface area is 320-700 m 2 / g, density is 100~250kg / m 3 .

[0036] The aerogel composite material is preferably a glass fiber aerogel composite felt, a ceramic fiber aerogel composite felt, an organic fiber aerogel composite material and a melamine foamed aerogel composite material.

[0037] The technical effects of the present invention are:

[0038] (1) By setting a counter-pressure dipping step, firstly, the sol and the polycondensing agent are respectively provided with relatively high pressure by means of a plunger pump or the like, so as to achieve counter-pressure in the mixing chamber of the counter-pressure dipping component, and efficient mixing is achieved in a very short time of counter-pressure process, and a certain kinetic energy is still retained after the counter-pressure, so that the catalytic sol can be uniformly transported to the upper surface of the substrate, and further penetrate into the interior of the substrate due to the existence of a slight impact force. More importantly, a negative pressure is provided at the lower part of the substrate, so that the further slow pressure enables the catalytic sol to further uniformly penetrate into the interior and the lower part of the substrate. By providing a negative pressure dipping device, the negative pressure generated accelerates the speed of immersing the catalytic sol flowing onto the surface of the substrate into the substrate, significantly improving the dipping speed, and controlling the amount of sol added and the dipping amount, thereby eliminating the dipping pool commonly used in the prior art. At the same time, due to the effect of gravity, the catalyzed sol continues to penetrate into the bottom of the substrate during the subsequent further transmission process, thereby achieving the technical effects of rapid dipping, continuous dipping and uniform dipping. By setting up a counter-pressure dipping method, the conveying speed of the substrate can be stably controlled at a conveying speed of 3 to 10 m / min or even higher. Further, by reasonably setting the counter-pressure and negative pressure, the depth of the catalytic sol immersed in the substrate is well matched with the conveying speed of the substrate, thereby enhancing the uniformity of the mutual immersion of the two. In the prior art, dipping is to transport the fiber felt into a container or a casting tray containing the catalytic sol, immerse the fiber felt in the catalytic sol, and coat the upper and lower surfaces of the fiber felt with the catalytic sol. However, due to the subsequent processing, the catalytic sol coated on the lower surface cannot be immersed in the fiber felt under the effect of gravity, so that the uniformity is poor. Even if the dipping and coating operations in the prior art are set within the transmission speed, the uniformity and depth of the dipping or coating cannot achieve the effect of the present invention.

[0039] (2) By arranging microwave (or ultrasonic) treatment in the aging step, the replacement step and the drying step, the composite gel is directly and rapidly heated in situ during the aging stage, and the temperature is set to 55-65°C, which significantly enhances the aging effect; in the replacement step, the composite gel and the replacement fluid are directly and rapidly heated in situ by microwave or ultrasonic, and the temperature is controlled at 55-65°C, which significantly improves the exchange rate between the replacement fluid and the water in the composite gel, and the replacement time can be significantly shortened to within 60 minutes (preferably within 30 minutes), significantly improving the production efficiency and production scale, and realizing continuous and automated production of aerogel composite materials; the drying temperature is set in the range of 65-120°C by microwave, which significantly improves the evaporation rate of the solvent on the surface of the composite gel and the migration rate of the solvent in the composite gel to the outer surface, so that the drying time can be significantly shortened, significantly improving the production efficiency and production scale, and realizing automated production of aerogel composite materials.

[0040] (3) In the prior art, even if part of the production is continuous, air seals or other forms of sealing are generally used. This is because the conveying speed of the assembly line is generally 2m / min. The present invention sets a sealing device in the form of a liquid seal, so that between each step, the gas flow is blocked by the upper part, and the composite gel or aerogel composite material is continuously passed by the lower liquid, so that the gas between each step is not connected. At the same time, a high-pressure inert gas injection air seal structure is set at the inlet and outlet of the sealing device, so that the efficient sealing of the entire assembly line is achieved. At the same time, the sealing device set by the present invention will not allow the gas after the liquid is vaporized to flow out, but will continue to condense back into the liquid, ensuring the relative stability of the liquid amount, thereby ensuring the continuity of the assembly line process and reducing the number of times the production needs to be interrupted due to the need to fill the liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The present invention is a schematic diagram of a process for a continuous production method at normal pressure according to an embodiment of the present invention.

[0042] Figure 2 This is a SEM image of the aerogel microstructure according to one embodiment of the present invention.

[0043] Figure 3 It is a comparison diagram of the distribution state of aerogel in the fiber matrix according to the embodiment of the present invention and the comparative embodiment.

[0044] in:

[0045] Figure 3 (a) is a schematic diagram of the distribution state of aerogel in a fiber matrix according to an embodiment of the present invention.

[0046] Figure 3 (b) Schematic diagram of the distribution of aerogel in the fiber matrix for comparison. DETAILED DESCRIPTION

[0047] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0048] The continuous production of the present invention is carried out using a normal pressure continuous production device, which includes a solution mixing component, an unwinding machine, a hedging negative pressure dipping component, a gel thickness determining component (optional according to actual conditions), a microwave aging tunnel component, a replacement tunnel component, a microwave drying tunnel machine, a hot air drying tunnel machine, a transmission component and a winding device.

[0049] The solution mixing component is used to prepare sol by mixing and stirring, and includes a stirring tank, a gear metering pump, and a weighing module. The stirring tank is equipped with a pH meter probe for monitoring the pH value, and the stirring tank is equipped with a temperature sensor for monitoring the temperature in the stirring tank.

[0050] The unwinding machine is used to support and unwind the substrate coil, and mainly unwinds the substrate coil through an unwinding tray to form a continuously unwound substrate.

[0051] The counter-pressure dipping component is used for performing online continuous dipping of the substrate unwound by the unwinder.

[0052] The gel thickness determining component is used to determine the thickness of the composite substrate containing the catalytic sol after dipping and to continuously gel, thereby completing the gelation process and obtaining a composite gel body.

[0053] The microwave aging tunnel component is used for continuously aging the gelled composite gel body by microwave treatment.

[0054] The replacement tunnel component is used for continuously replacing the solvent of the aged composite gel.

[0055] The microwave drying tunnel machine is used to continuously dry the composite gel after solvent replacement at normal pressure by microwave treatment.

[0056] The hot air drying tunnel machine is used to dry the microwave-dried aerogel composite material by hot air, remove the residual solvent in the aerogel composite material, and quickly dissociate the residual alcohol molecules by hot air.

[0057] The winding device is used to carry out a winding process on the aerogel composite material obtained after hot air drying.

[0058] The unwinding machine, the hedging negative pressure glue dipping component, the gel thickness setting component, the microwave aging tunnel component, the replacement tunnel component, the microwave drying tunnel machine, the hot air drying tunnel machine and the winding device are arranged in sequence, and the hedging negative pressure glue dipping component, the gel thickness setting component, the microwave aging tunnel component, the replacement tunnel component, the microwave drying tunnel machine, the hot air drying tunnel machine and the winding device are connected through the transmission component.

[0059] Example 1

[0060] like Figure 1 The atmospheric pressure continuous production method of the aerogel composite material shown comprises the following steps:

[0061] Step S1, preparing a sol, adding alkyl siloxane, water, alcohol solvent and hydrolyzing agent respectively according to the ratio requirements, mixing and stirring in a stirring tank I for 4 to 6 hours to obtain a first solution, adding silica sol, water and quaternary ammonium salt compound respectively in a stirring tank II, mixing and stirring for 0.5 to 4 hours to obtain a second solution, adding the second solution to the obtained first solution in a stirring tank I, mixing and stirring for 0.2 to 1 hour to obtain a sol.

[0062] The preparation steps of the first solution in this embodiment include: weighing alkyl siloxane, ethanol and water and mixing them evenly, then adding a hydrolyzing agent and stirring evenly to obtain a first solution. Specifically, the weight ratio is calculated according to m (alkyl siloxane): m (ethanol): m (water): m (hydrolyzing agent) = 1: (0.1-6): (0.1-6):

[0063] (0.001-0.005), in this embodiment, it is set to 1:1.67:3.19:0.0035, the weight concentration of the hydrolyzing agent is 10%, and the first solution is obtained by mixing for 4-6 hours, and in this embodiment, it is mixed for 4 hours. The alkyl siloxane includes one or more of methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, vinyltriethoxysilane, propyltrimethoxysilane or propyltriethoxysilane. In this embodiment, methyltrimethoxysilane is selected.

[0064] The steps of preparing the second solution in this embodiment include: weighing silica sol, water and quaternary ammonium salt compound and mixing them evenly to obtain a second solution. Specifically, the weight ratio is counted according to m (silica sol): m (water): m (quaternary ammonium salt compound) = 1: (0.1-6): (0.01-0.6), and this embodiment is set to 1: 2.19: 0.2, and mixed for 0.2-4 hours to obtain the second solution. In this embodiment, the mixing is 2 hours. The silica sol is one or more of acidic silica sol, neutral silica sol or alkaline silica sol; the quaternary ammonium salt compound is one or more of hexadecyl trimethyl ammonium chloride, dodecyl trimethyl ammonium chloride or tetramethyl ammonium chloride. Hexadecyl trimethyl ammonium chloride is selected in this embodiment.

[0065] The steps of preparing the sol in this embodiment include: weighing the first solution and the second solution and mixing them evenly to obtain the sol. Specifically, the volume ratio is counted according to V (first solution): V (second solution) = (1-8): (1-8), which is set to 1:2 in this embodiment. Mix for 0.2-4 hours to obtain the sol, and mix for 1 hour in this embodiment.

[0066] Prepare a polycondensation agent, which is obtained by mixing and stirring an alkaline substance and water for 5 to 20 minutes, and in this embodiment, stirring for 15 minutes. The alkaline substance is one or a combination of two of sodium hydroxide, potassium hydroxide, ammonia water, ammonium fluoride, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, ethanolamine, diethanolamine, methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, isopropanolamine, aniline, o-phenylenediamine, m-phenylenediamine or p-phenylenediamine.

[0067] Step S2, unwinding, unwinding the substrate coil, and setting the forward speed of the substrate coil to 5 m / min.

[0068] Step S3, negative pressure dipping, according to the ratio requirement, the sol and condensation agent prepared in the measured step 1 are mixed for 2-20S, the input pressure of the two substances to be hedged is controlled to 5MPa, and they are quickly immersed in the substrate, and the pressure of the negative pressure in the space below the substrate is -50kPa; the ratio requirement in this embodiment is that the sol and condensation agent prepared in step S1 are counted by volume ratio, V(sol):V(condensation agent)=(1~4):(1~4), which is set to 1:2 in this embodiment, and are quickly poured onto the substrate after being hedged and mixed at room temperature.

[0069] Step S4, gel thickness setting, after dipping, the dipped substrate is leveled under double belt roller pressure, gelled under restraining pressure, the gel time is 0.5 to 5 minutes, and the thickness of the dipped substrate is fixed by setting the gap between the rollers.

[0070] Step S5, microwave aging, after gelation, the composite gel is heated in situ with microwaves, controlled at 60°C, and aged for 30 minutes. The microwave aging treatment enhances the skeleton strength of the wet silica gel, enables more Si-O-Si bonding, and forms a more stable gel network structure of the wet gel, promotes the retention of the pore structure in the subsequent drying process, and thus improves the mechanical stability of the composite gel. The gelled wet gel can be aged within an appropriate temperature range to reduce the microporous structure of the gel, enhance the optimal pore structure, and increase the permeability and mechanical properties of the gel.

[0071] Step S6, solvent replacement, after aging, the composite gel and the replacement fluid are heated in situ by microwave or ultrasonic heating of the replacement fluid, controlled at 60°C, and the replacement is carried out for 30 minutes. Microwave in situ heating allows the water in the wet silica gel to be quickly replaced by the alcohol solvent, so as to facilitate the subsequent atmospheric pressure drying process to maintain the stability of the pore structure. The replacement step can remove the water in the gel to the greatest extent, so as to maintain the stability of the pore structure after the subsequent atmospheric pressure drying process, thereby improving the stability of the performance of the aerogel composite material.

[0072] Step S7, microwave drying, after replacing the solvent, using microwave to heat the composite gel in situ, controlling the temperature at 110° C., and drying for 30 minutes.

[0073] Step S8, drying: after drying, the aerogel composite material of step S7 is dried with hot air to remove the residual alcohol and the like in the aerogel composite material, and the temperature is controlled at 160° C. and the drying is performed for 30 minutes.

[0074] Step 10: Rolling up: After drying, the aerogel composite material is rolled up.

[0075] By testing the product obtained in Example 1, it was found that the thermal conductivity of the aerogel composite material at room temperature was 0.0186 W / mk and the specific surface area was 486 m 2 / g, density is 200kg / m 3 The obtained aerogel composite material was observed, such as Figure 2 This is a SEM photo of the aerogel microstructure of this embodiment. It can be seen from the figure that the granular structure is evenly distributed; Figure 3 (a) is a picture showing the distribution of aerogel in the fiber matrix in the product obtained in this example. It can be seen from the picture that the distribution of aerogel in the matrix is ​​basically consistent.

[0076] Comparative Example 1

[0077] This comparative example shows a comparison method without counter-pressure dipping. The other settings of this comparative example are the same as those of Example 1, except that the substrate is continuously immersed in a cavity containing the catalytic sol prepared in step S1, and the substrate is completely introduced into the cavity through multiple guide rollers. After the surface of the substrate contacts the catalytic sol, the catalytic sol is immersed in the substrate. The product obtained by this comparative example is tested to have a thermal conductivity of 0.0231 W / mk at room temperature, and a specific surface area of ​​the aerogel of 340 m 2 / g, and the obtained aerogel composite material was observed. Figure 3 (b) is a picture of the distribution state of aerogel in the fiber matrix in the product obtained in this comparative example. It can be found from the figure that the aerogel is unevenly distributed, indicating that there is a problem of insufficient local impregnation. It can be seen that in the continuous production method of the present invention, the absence of counter-pressure impregnation will have a significant adverse effect on the uniformity and application performance of the product. It also shows that the counter-pressure impregnation is closely coordinated with the overall continuous production of the present invention and the setting of other steps.

[0078] Comparative Example 2

[0079] This comparative example shows that microwave heating is not used. The other settings of this comparative example are the same as those of Example 1. The difference is that microwave or ultrasonic heating is not used in the aging, solvent replacement and normal pressure microwave drying steps. Instead, the existing hot water or resistance wire is used to heat the air for heat conduction to obtain the desired treatment results. The required replacement time is 6 hours and the drying time is 2 hours. The product obtained by testing the comparative example has a thermal conductivity of 0.0225 W / m·k at room temperature and a specific surface area of ​​352 m 2 / g,, it can be seen that the rapid continuous production set by the present invention has a close coordination relationship with the heating method (rapid heating), and if the existing heating method is used, it not only cannot meet the requirements of the rapid continuous production of the present invention, but also the performance is reduced to a certain extent, that is, the microwave or ultrasonic setting method set by the present invention is coordinated with the overall process, and simply changing the heating method not only eliminates the independent effect of the ultrasonic or microwave, but also affects the performance of the final product, thereby proving that the setting of other steps and parameters is closely coordinated, and at the same time, the microwave or ultrasonic parameters and the heating temperature setting are also closely coordinated with the specific setting of the rapidity of the present invention.

[0080] The above-mentioned embodiments and comparative examples of the present invention are all examples and do not have a limiting effect on the protection scope of the technical solution. The fact that there is no comparison of technical features does not mean that there are no outstanding substantial features, but only uses textual description to illustrate its setting method. The above-mentioned embodiments are preferred implementation methods of the present invention, but the implementation methods of the present invention are not limited to the above-mentioned embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principle of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for continuous production of an aerogel composite material at normal pressure, characterized in that: The steps include: S1, preparing a sol and a polycondensation agent, adding an alkylsiloxane, water, an alcohol and a hydrolyzing agent into a stirring tank I of a solution mixing component to obtain a first solution, adding a silica sol, water and a quaternary ammonium salt compound into a stirring tank II of a solution mixing component to obtain a second solution, and adding the second solution into the stirring tank I of the prepared first solution to obtain a sol; After mixing water and an alkaline substance and stirring, a polycondensation agent is obtained; S2, unwinding, unwinding the substrate coil by an unwinder, unfolding the substrate coil into a transmission component and continuously moving it back and forth; S3, counter-pressure dipping, the sol and the polycondensing agent prepared in step S1 are respectively input into the mixing chamber of the counter-pressure dipping component through relatively arranged high-pressure input ports in a counter-pressure manner for counter-mixing to obtain a catalytic sol; the counter-mixed catalytic sol is then transported through the output port of the mixing chamber to the substrate unwound by the unwinder in step S2 and introduced into the counter-pressure dipping component, and negative pressure is set in the space below the substrate, and the catalytic sol transported to the substrate through the discharge port of the mixing chamber by the negative pressure is uniformly impregnated with the substrate to obtain a composite substrate containing the catalytic sol after dipping; S4, gel thickness determination, continuously conveying the composite substrate containing the catalytic sol after the dipping treatment in step S3 to a gel thickness determination device, rolling and leveling the composite substrate containing the catalytic sol, and setting the gap thickness during the rolling process to determine the thickness of the composite substrate containing the catalytic sol, and achieving gelation during the thickness determination operation; S5, aging, continuously conveying the composite gel obtained after the gel treatment in step S4 to a microwave aging tunnel component, subjecting the composite gel to microwave heating in the microwave aging tunnel component, to obtain an aged composite gel; S6, solvent replacement, continuously transporting the aged composite gel obtained in step S5 to a replacement tunnel component provided with a microwave treatment device or an ultrasonic treatment device, and replacing water in the aged composite gel with a replacement liquid; S7, normal pressure microwave drying, continuously conveying the composite gel obtained after the solvent replacement treatment in step S6 to a microwave drying tunnel machine, subjecting the composite gel after the replacement treatment to microwave heating in the microwave drying tunnel machine, to obtain a dried aerogel composite material; S8, hot air drying, continuously conveying the aerogel composite material obtained after microwave drying in step S7 to a hot air drying tunnel machine, and performing rapid heating and drying treatment by making the hot air be non-parallel to the traveling direction of the continuously input aerogel composite material; S9, rolling up, using a rolling device to roll up the aerogel composite material obtained after hot air drying in step S8 to obtain an aerogel composite material roll product; Steps S2 to S9 are continuous and uninterrupted assembly line production.

2. The method for continuous production of aerogel composite materials at normal pressure according to claim 1, characterized in that: In step S1, alkyl siloxane, water, alcohol solvent and hydrolyzing agent are mixed and stirred in a stirring tank I for 4 to 6 hours to obtain a first solution, and silica sol, water and quaternary ammonium salt compound are mixed and stirred in a stirring tank II for 0.5 to 4 hours to obtain a second solution, and the second solution is added to the obtained first solution in the stirring tank I and mixed and stirred for 0.2 to 2 hours to obtain a sol; The stirring time after mixing water and alkali is 5 to 20 minutes.

3. The method for continuous production of aerogel composite materials at normal pressure according to claim 1, characterized in that: In step S3, the time of counter-mixing is 2 to 20 seconds; In step S4, while the thickness determination operation is being performed, gelation is achieved within 0.5 to 5 minutes.

4. The method for continuous production of aerogel composite materials at normal pressure according to claim 1, characterized in that: In step S5, the microwave heating temperature is controlled at 55-65° C., and the microwave aging time is 21-60 min; In step S6, the temperature of microwave heating or ultrasonic heating during heating by the microwave treatment device or ultrasonic treatment device is controlled at 55 to 65° C., and the cyclic replacement treatment time is 20 to 58 minutes; In step S7, the microwave heating temperature is controlled at 65-120° C., and the microwave drying time is 20-60 min. In step S8, the hot air is at a vertical angle to the direction of travel of the aerogel composite material to perform rapid heating and drying treatment; In step S8, the hot air temperature is controlled to be 85-180° C., and the hot air drying process time is 18-62 minutes.

5. The method for continuous production of aerogel composite materials at normal pressure according to claim 1, characterized in that: Step S4 is replaced by: S4, gelation, continuously conveying the composite substrate containing the catalytic sol after the dipping treatment in step S3 to a gel thickness setting device, and performing gelation treatment on the composite substrate containing the catalytic sol by rolling and leveling the composite substrate containing the catalytic sol.

6. The method for continuous production of aerogel composite materials at normal pressure according to claim 1, characterized in that: In step S2, the unwinding forward speed is 3 to 10 m / min.

7. The method for continuous production of aerogel composite materials at normal pressure according to claim 1, characterized in that: In step S3, the sol is transported to the mixing chamber by a plunger pump, and the pressure of the sol input is controlled to be 0.3~10MPa. The condensation agent is discharged into the mixing chamber by a plunger pump, and the pressure of the condensation agent input is controlled to be 0.5~11MPa; the negative pressure of the space below the substrate is -5~-70kPa.

8. The method for continuous production of aerogel composite materials at normal pressure according to claim 1, characterized in that: In step S3, the discharge port of the mixing chamber is provided with a glue coating head having a slit; In step S4, before rolling and leveling the composite substrate containing the catalytic sol, the composite substrate containing the catalytic sol is pre-gelled in a pre-gel box by heating with hot water. The temperature of the hot water heating is 35 to 45°C. The gel thickness setting device controls the thickness of the composite substrate containing the catalytic sol to 0.5 to 15.0 mm, and the thickness accuracy is ±0.15 mm.

9. The method for continuous production of aerogel composite materials at normal pressure according to claim 1, characterized in that: A liquid-sealing device is provided between step S4 and step S5, between step S5 and step S6, between step S6 and step S7, and between step S7 and step S8. The interior of the liquid-sealing device is filled with liquid, and a vertical partition whose bottom is immersed in the filled liquid is provided at the inner top of the liquid-sealing device. The composite gel or aerogel composite material is continuously transported to the liquid-sealing device from the inlet of the liquid-sealing device, and is immersed in the liquid through one end of the vertical partition and passes through the liquid under the vertical partition under the conduction of the guide roller provided in the liquid-sealing device, and then leaves the liquid from the other end of the vertical partition, and is continuously transported out through the outlet of the liquid-sealing device, so as to realize the sealed isolation of the gas between the input port and the output port through the liquid-sealing device; the liquid-sealing device or the inert gas sealing device is provided between step S8 and step S9, and the inert gas sealing device is a sealing device in which the part through which the aerogel composite material passes is filled with inert gas and other gases are excluded.

10. An aerogel composite material, characterized in that: The aerogel composite material is prepared by the normal pressure continuous production method according to any one of claims 1 to 9, wherein the thermal conductivity of the aerogel composite material at room temperature is 0.016 to 0.021 W / m·k, and the specific surface area is 320 to 700 m 2 / g, density is 100~250kg / m 3 .

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