A secondary modification system and method for aerogel materials

Abstract

This invention relates to a system and method for secondary modification of aerogel materials, comprising: a winding mechanism for layering and winding a wet gel to be hydrophobically modified into an aerogel; and a modification mechanism for secondary modification of the wet gel that has undergone preliminary modification during the preparation process. The winding mechanism winds the wet gel and the flow guide net of the modification mechanism onto a winding tray in an alternating winding manner. The wet gel and the flow guide net form several alternating circular layered structures in the winding state. The flow guide net is equipped with drainage channels that guide the contact mode and contact time of the modification liquid provided by the modification mechanism for secondary modification of the wet gel. By designing the drainage channels of the flow guide net, the modification efficiency and effect of the modification liquid on the wet gel are enhanced. The modification liquid is recycled through a circulation pipeline, reducing the loss of the modification liquid.

Description

Technical Field

[0001] This invention relates to the field of aerogel technology, and in particular to a system and method for secondary modification of aerogel materials. Background Technology

[0002] Aerogels are nanomaterials with a three-dimensional network structure. They possess properties such as low thermal conductivity, low density, high porosity, high specific surface area, and low dielectric constant. Aerogels exhibit excellent performance in thermal insulation, adsorption, electrochemistry, and sound insulation. Specifically, aerogels are solid gel materials with a nanoporous network structure where gas replaces liquid components, and they have broad application prospects in aerospace, defense, biomimetic medicine, energy-efficient buildings, petrochemicals, and cold chain transportation. However, because the gel structure and physical properties of aerogels deteriorate when they absorb moisture, there is a need to develop a method to prevent aerogels from absorbing moisture from the air for long-term use in industry. Therefore, a method has been proposed to prepare aerogels with long-lasting hydrophobicity by hydrophobic modification of the aerogel surface.

[0003] For example, the prior art, such as the patent document with publication number CN115417958A, discloses a method for preparing hydrophobically modified thermosetting phenolic resin and a method for preparing aerogel and aerogel-based composite materials, which relates to the field of phenolic resin-based composite materials technology. The method for preparing the hydrophobically modified thermosetting phenolic resin includes the following steps: S11: Mixing and dissolving the thermosetting phenolic resin and a solvent to obtain a solution; S12: Adding a protic acid catalyst and a modifying solution sequentially to the solution, then injecting it into a reaction vessel, and reacting at 65℃~75℃ for 10~14h. Then adding a Lewis acid catalyst, and continuing the reaction under reflux at 70~85℃ for 22~26h to obtain a reaction solution; S13: Concentrating under reduced pressure to remove the solvent from the reaction solution, followed by washing with water and drying to obtain the hydrophobically modified thermosetting phenolic resin.

[0004] For example, the prior art, such as the patent document with publication number CN110255568A, proposes a method for synthesizing and applying a double-layered amino-modified silica aerogel. The specific steps are as follows: Take 20 ml of water glass and remove sodium ions from the water glass using a cation exchange resin column; adjust the pH of the obtained silicic acid solution to 4.0-8.0 using 0.1-2.0 mol / L ammonia solution and 0.1-2.0 mol / L hydrochloric acid solution; quickly sonicate the beaker containing the silicic acid solution, and sequentially add a mixed modifier of epichlorohydrin, APTES, ethylenediamine and n-hexane in a volume ratio of 1:1:1:16 to the silicic acid solution. Under sonication, slowly shake the beaker until the solution forms a gel. Then, place the gel at 30-65℃ for 5-24 hours, and then add 28 ml of n-hexane to the gel. Under 30-65℃, continuously shake for 5-24 hours. Finally, the aerogel was dried by vacuum freeze-drying for 10-48 hours to obtain an inner and outer double-layer amine-modified silica aerogel.

[0005] In the aforementioned hydrophobic modification schemes for aerogels, most schemes focus on improving the modifying liquid used for hydrophobic modification. However, the degree of hydrophobic modification is not only related to the materials used in aerogel preparation, their proportions, and the amount and proportion of the modifying liquid, but also to the contact area and contact time between the wet gel (an intermediate product in aerogel preparation) and the modifying liquid during the hydrophobic modification process. In conventional modification processes, the modifying liquid is usually added directly to the wet gel during preparation, followed by drying and shaping. However, this method yields poor hydrophobic modification results. By continuously refining the modifying liquid, the hydrophobic modification effect of the aerogel can be further improved by modifying the contact method between the modifying liquid and the wet gel.

[0006] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the inventors studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0007] In view of the shortcomings of the prior art in terms of poor hydrophobic modification effect, the present invention provides a secondary modification system and method for aerogel materials, aiming to solve at least one or more technical problems existing in the prior art.

[0008] This invention provides a system and method for performing hydrophobic modification treatment on intermediate wet gels through multiple cyclic liquid re-liquidation during the preparation of aerogels. In the design of the technical solution of this invention, the design of the guide net and the drainage channels on the guide net enables uniform and sufficient contact between the modified liquid and all parts of the wet gel. On the basis of improving the properties and performance of the modified liquid itself, the utilization efficiency of the modified liquid is improved, the production cost is reduced, and aerogels with better hydrophobic modification effect are obtained.

[0009] To achieve the above objectives, this application proposes a secondary modification system for aerogel materials, comprising: a winding mechanism for performing a layered winding process on a wet gel to be hydrophobically modified into an aerogel; and a modification mechanism for performing secondary modification on the wet gel that has undergone preliminary modification during the preparation process.

[0010] Preferably, the winding mechanism winds the wet gel and the flow guide net from the modification mechanism onto the winding tray of the winding mechanism in an alternating winding manner. In the winding state, the wet gel and the flow guide net form several alternating circular hierarchical structures. The flow guide net is equipped with drainage channels that guide the contact mode and contact time between the modified liquid provided by the modification mechanism for secondary modification of the wet gel and the wet gel. The winding mechanism achieves the alternating winding of the wet gel and the flow guide net by driving the extension shaft on the winding tray to rotate. In the winding state, the wet gel and the flow guide net form an alternating cylindrical hierarchical structure. The modified liquid is then injected into the wet gel and the flow guide net from one end of the cylindrical hierarchical structure. The design of the flow guide channels in the flow guide net improves the utilization efficiency of the modified liquid and increases the effective time and effective contact area of ​​the modified liquid, thereby improving the modification effect.

[0011] Preferably, the winding mechanism includes a winding device for alternately winding the wet gel and the flow guide net onto a winding tray, and an unwinding device for disassembling the wet gel and the flow guide net after modification. The winding device is capable of alternately winding and wrapping the wet gel and the flow guide net, which are filled in the substrate, onto the extension shaft of the winding tray by driving the extension shaft arranged on the winding tray to rotate. The unwinding device, after the cyclic modification is completed, drives the extension shaft to rotate in the opposite direction to the winding direction to unwind the wet gel and the flow guide net.

[0012] Preferably, in the winding state, the circular bottom surface formed by the winding of the wet gel and the flow guide net is placed on the winding tray, and the cylindrical structure formed by the winding of the wet gel and the flow guide net is fitted onto the extension shaft extending from the winding tray. In particular, the extension shaft on the winding tray is specifically located at the center of the winding tray, and the extension shaft is perpendicular to the plane of the winding tray, thereby facilitating the winding of the wet gel and the flow guide net onto the winding tray.

[0013] Preferably, both the winding tray and the extension shaft have several holes on their surfaces that allow the modified liquid to flow through. The winding tray serves as the connecting base for the extension shaft, and the extension shaft is arranged orthogonally to the winding tray. Specifically, during the modification process, the extension shaft can drive the wet gel and the guide net in the entire winding state to rotate. When the modified liquid flows from one end of the wet gel and the guide net to the other end in the winding state, the centrifugal force generated by the rotation will accelerate the flow efficiency of the modified liquid between the layers of the wet gel and the guide net. Through the holes provided on the winding tray and the extension shaft, it can be fully ensured that the unused modified liquid is removed from the wet gel and the guide net and flows to the bottom of the receiving cavity. Then, the pump body located at the bottom will circulate the unused modified liquid from the bottom of the receiving cavity into the interior of the wet gel and the guide net, thereby achieving efficient utilization of the modified liquid.

[0014] Preferably, the guide net is provided with several main channels along the direction of the extension axis. The main channels can guide the modified liquid from the end of the wet gel in the winding state and the guide net away from the winding tray to the end near the winding tray.

[0015] Preferably, on several main channels, each main channel has branch channels symmetrically distributed on both sides of the main channel.

[0016] Preferably, the branch channels extend from the main channel by a predetermined distance in a manner that connects with each other before merging into the main channel, and the diameter of the branch channels is larger than the diameter of the main channel.

[0017] In this invention, the main channel of the drainage channel is divided into multiple flow paths by the branch channels, thereby enhancing the fluidity of the modified liquid in the drainage channel. This facilitates the rapid flow of the modified liquid between the wet gel layers and also allows other solvents or solutes displaced by the modification to flow out of the wet gel and the guide net for easy discharge. This prevents the modified liquid and other solvents from remaining between the layers and failing to make sufficient contact with the wet gel, which would lead to a decrease in the modification effect.

[0018] Preferably, the branch channels symmetrically distributed on both sides of the main channel are connected by several branch channels. The diameter of the branch channels is smaller than the diameter of the branch channels and / or the main channel. The main channels are spaced apart from each other, and the branch channels are distributed within the intervals between the main channels. The branch channels can further control or improve the flow rate and pressure changes of the modifier solution at each input or output node of the drainage channel. The pressure difference is used to promote the continuous and smooth flow of the modifier solution inside the drainage channel, so as to guide the modified liquid to flow continuously through and diffuse into the wet gel between the flow guide mesh layers, thereby completing the hydrophobic modification of the wet gel material.

[0019] Preferably, the wet gel held on the winding tray in the winding state and the guide net are placed in the receiving cavity of the modification mechanism. The modification liquid is drawn from the bottom of the receiving cavity by the pump and injected into the drainage channel of the guide net from the top of the receiving cavity in a preset manner.

[0020] This application also provides a method for secondary modification of aerogel materials, characterized in that a wet gel that has undergone preliminary modification is provided for preparing aerogel materials.

[0021] Furthermore, the wet gel and the guide net of the modification mechanism are wound onto the winding tray of the winding mechanism in an alternating winding manner using a winding mechanism, and placed inside the receiving cavity of the modification mechanism.

[0022] Furthermore, the modified liquid is injected from the top of the receiving cavity into the drainage channel of the guide net, and the modified liquid flowing through the wet gel and the guide net is extracted from the bottom of the receiving cavity by the pump and circulated into the drainage channel of the guide net according to the preset method for secondary modification.

[0023] Furthermore, the winding mechanism winds the wet gel and the guide net of the modification mechanism onto the winding tray of the winding mechanism in an alternating winding manner. The wet gel and the guide net form several alternating circular hierarchical structures in the winding state. The guide net is equipped with a flow channel that can guide the contact mode and contact time of the modification liquid provided by the modification mechanism for secondary modification of the wet gel.

[0024] This invention, through the design of a flow-guiding net and the flow channels within the net, ensures uniform flow of the modified liquid within the wet gel, the intermediate product in the preparation of aerogels, guaranteeing effective and sufficient contact between the modified liquid and all the wet gel. Simultaneously, it shortens the modification time, thereby improving the production efficiency of aerogel materials, effectively reducing production costs, enhancing the product's competitiveness in the industry, and this invention can be implemented in large-scale actual production. The resulting aerogel composite material exhibits extremely strong hydrophobicity, with the hydrophobic effect not easily compromised, while also possessing excellent thermal insulation properties and a flame retardant rating of 94-V0. Attached Figure Description

[0025] Figure 1 This is a simplified overall structural diagram of the secondary modification system of the present invention;

[0026] Figure 2 This is a simplified structural diagram of the flow guide net of the present invention;

[0027] Figure 3 This is a simplified structural diagram of the wet gel and the flow guide net in the wound state of the present invention;

[0028] Figure 4 This is a side view of the winding tray structure of the present invention;

[0029] Figure 5 This is a top view of the winding tray of the present invention.

[0030] List of reference numerals

[0031] 100: Wet gel; 200: Guide net; 300: Circulation pipeline; 201: Main channel; 202: Branch channel; 203: Branch branch channel; 204: Merging channel; 301: Rewinding tray; 302: Extension shaft; 303: Hole; 304: Receiving cavity; 305: Top cover; 306: Bottom cover; 307: Vent; 308: Liquid outlet; 309: Liquid injection port; 310: Pump body interface; 311: Spraying disc. Detailed Implementation

[0032] The following is in conjunction with the appendix Figure 1-5 The present invention will be described in detail below.

[0033] Example 1

[0034] To address the shortcomings of existing technologies that do not consider the contact area and contact time during the modification process between the modifying liquid and the wet gel 100, this application proposes a secondary modification system for aerogel materials, comprising: a winding mechanism for layering and winding the wet gel 100 to be hydrophobically modified into an aerogel; and a modification mechanism for performing secondary modification on the wet gel 100 that has undergone preliminary modification during the preparation process.

[0035] Preferably, such as Figure 1 and Figure 2 As shown, the winding mechanism winds the wet gel 100 and the flow guide net 200 of the modification mechanism onto the winding tray 301 of the winding mechanism in an alternating winding manner. The wet gel 100 and the flow guide net 200 form several alternately distributed circular layered structures in the winding state. The flow guide net 200 is equipped with a flow channel that can guide the contact mode and contact time between the modification liquid provided by the modification mechanism for secondary modification of the wet gel 100 and the wet gel 100. The winding mechanism drives the extension shaft 302 on the winding tray 301 to rotate, thereby achieving the staggered winding and wrapping of the wet gel 100 and the flow guide net 200. In the winding state, the wet gel 100 and the flow guide net 200 form an alternating cylindrical hierarchical structure. The modified liquid is then injected into the wet gel 100 and the flow guide net 200 from one end of the cylindrical hierarchical structure. The design of the flow guide net 200 improves the utilization efficiency of the modified liquid and increases the effective time and effective contact area of ​​the modified liquid, thereby improving the modification effect.

[0036] Specifically, the thickness of the flow guide net 200 is preferably set to 0.1-5mm, or the thickness of the flow guide net 200 is determined according to the thickness of the actual substrate used. The thickness of the flow guide net 200 is not less than 5%-20% of the thickness of the aerogel roll material, preferably 15%.

[0037] Specifically, at least one layer of flow guiding net 200 is arranged between the layers of the roll wet gel 100. Optionally, multiple layers of flow guiding net 200 can be stacked between the layers to meet the real-time thickness requirements.

[0038] Specifically, the width of the guide net 200 shall not be less than 80% of the width of the aerogel roll product.

[0039] Preferably, the guide net 200 is provided with a plurality of main channels 201 along the direction of the extension axis 302. The main channels 201 can guide the modified liquid from the end of the wet gel 100 in the winding state and the guide net 200 away from the winding tray 301 to the end near the winding tray 301.

[0040] Specifically, in this invention, such as Figure 2 As shown, a flow-guiding mesh 200 of a certain thickness is provided with several drainage channels for guiding the modifier solution to flow continuously and unobstructed between the layers of the wet gel 100. In particular, the drainage channels allow the modifier liquid to flow smoothly within the gaps between the layers of the wet gel 100, thereby achieving hydrophobic modification of the roll-shaped composite wet gel 100 material.

[0041] Preferably, on a plurality of main channels 201, each main channel 201 is provided with branch channels 202 on both sides of the main channel 201, which are symmetrically distributed based on the main channel 201.

[0042] Preferably, the branch channel 202 extends from the main channel 201 by a predetermined distance in a manner that connects with each other and then merges into the main channel 201. The diameter of the branch channel 202 is larger than the diameter of the main channel 201.

[0043] In this invention, the main channel 201 of the drainage channel is divided into multiple flow paths by the branch channel 202, thereby enhancing the fluidity of the modified liquid in the drainage channel. This facilitates the rapid flow of the modified liquid between the layers of the wet gel 100, and also facilitates the outflow of other solvents or solutes displaced by the modification from the wet gel 100 and the guide net 200 for external discharge. This prevents the modified liquid and other solvents from remaining between the layers and failing to make sufficient contact with the wet gel 100, which would lead to a decrease in the modification effect.

[0044] Preferably, the branch channels 202 symmetrically distributed on both sides of the main channel 201 are connected by a number of branch channels 203. The diameter of the branch channels 203 is smaller than the diameter of the branch channels 202 and / or the main channel 201. The main channels 201 are spaced apart from each other, and the branch channels 202 are distributed within the intervals between the main channels 201. The branch channels 203 can further control or improve the flow rate and pressure changes of the modified liquid at each input or output node of the drainage channel. The pressure difference is used to promote the continuous and smooth flow of the modified liquid inside the drainage channel, so as to guide the modified liquid to flow continuously through and diffuse into the wet gel 100 between the layers of the guide net 200, thereby completing the hydrophobic modification of the wet gel 100 material.

[0045] Specifically, the drainage channel consists of several main channels 201 arranged along the extension axis 302 and several branch channels 202 connected to the main channels 201 and symmetrically distributed on both sides of the main channels 201. Each main channel 201 is spaced at the same distance, and the branch channels 202 are mainly located within the intervals between the main channels 201. Specifically, several branch trunk channels 203 are also included between two branch channels 202 symmetrically distributed based on each main channel 201.

[0046] Preferably, two or more branch channels 202 can be provided based on the symmetrical distribution of each main channel 201. The configuration of each branch channel 202 within the same guide net 200 is always consistent, ensuring that the drainage channels in the guide net uniformly guide the modified liquid. Furthermore, for the branch channels 202 between multiple main channels 201, the branch channels 202 are always staggered. That is, for two adjacent main channels 201, only one main channel 201 is provided at the same height. For two adjacent main channels 201, the protrusions and depressions formed by the branch channels 202 are staggered, thereby minimizing the uncovered area of ​​the drainage channels on the guide net. In this configuration, the drainage channels on the guide net 200 are set into several pathways, maximizing the contact area and contact time between the modified liquid and the wet gel 100 within the drainage channels, thereby improving the modification effect.

[0047] Preferably, the branch channels 202 expand outwards on both sides of the main channel 201 and then converge and contract towards the main channel 201. Specifically, the branch channels 202 are arc-shaped channels, and the branch channels 202 symmetrically arranged on both sides of the main channel 201 are generally elliptical in shape. At the branch channels 202, the branch channels 202 on both sides and the main channel 201 together form three interconnected pathways. Among them, two branch channels 202 are curved, and the main channel 201 in the middle is straight. Specifically, on the same main channel 201, there are several such elliptical branch channels 202 and several branch channels 202 forming three-way passages with the main channel 201. Between each three-way passage, the main channel 201 will extend a certain distance on its own. At this certain distance, the three-way passages will merge into the main channel 201 for easy distinction. The passage after the three-way passages merge is called the merging channel 204. Another main channel 201 adjacent to the main channel 201 will be equipped with the same branch channels 202 and three-way passages at the height of the merging channel 204.

[0048] Preferably, the sum of the diameters of the multiple branch channels 202 and the main channel 201 within the branch channels 202 is greater than or equal to the diameter of the confluence channel 204. Alternatively, the diameter of any branch channel 202 or main channel 201 is greater than the diameter of the confluence channel 204. In this configuration, the velocity of the modified liquid flowing through the branch channels 202 is less than the velocity flowing through the confluence channel 204.

[0049] Specifically, when the modified liquid flows along the wet gel 100 layer through the drainage channel in the guide net 200, the main channel 201 of the drainage channel is divided into multiple flow paths with reduced diameters by the branch channel 202. This enhances the fluidity of the modified liquid in the drainage channel (i.e., increases the flow rate of the modified liquid), which is beneficial for the rapid flow of the modified liquid between the wet gel 100 layers. At the same time, it is also beneficial for other solvents or solutes displaced by modification to flow out of the composite wet gel 100 layer for easy discharge. This avoids the modified liquid and other solvents from remaining between the layers and failing to make sufficient contact with the wet gel 100, which would lead to a decrease in the modification effect. Therefore, this is crucial for the preparation of hydrophobic aerogel materials.

[0050] Preferably, the main channel 201, composed of multiple branch channels 202, has an ellipsoidal annular channel with a generally centrally raised shape. Further, the sides of the branch channels 202 located on both sides of the ellipsoidal annular channel have a generally streamlined structure. The main channel 201 in the middle region of the ellipsoidal annular channel is interconnected with the two or more branch channels 202 constituting the ellipsoidal annular channel, and both the branch channels 202 and the main channel 201 are connected to the confluence channel 204. In particular, the radius of curvature at the front end of the branch channel 202 on the ellipsoidal annular channel is preferably larger than the radius of curvature at its rear end. Therefore, when the modified liquid flows from the confluence channel 204 through the ellipsoidal annular channel, vortices can be formed within the drainage channel to prevent the modified liquid from stagnating within the drainage channel, thereby helping the modified liquid to flow out within the guide net 200 as much as possible.

[0051] Preferably, the ellipsoidal circulation channel formed by the branch channels 202 of the diversion channel further includes multiple branch channels 203 arranged in a manner that can connect the branch channels 202 forming the arc-shaped channel of the ellipsoidal circulation channel. In particular, the diameter of the multiple branch channels 203 can be smaller than the diameter of the multiple branch channels 202 or the merging channel 204.

[0052] Preferably, multiple branch channels 203 form a roughly "Y"-shaped branch channel between adjacent branch channels 202. Each branch channel 203 is connected to the branch channel 202 of each ellipsoidal circulation channel through a "Y"-shaped structure. Within the same ellipsoidal circulation channel, the branch channels 203 connect the ends of the "Y"-shaped structure. That is, the specific structure of the branch channels 203 is that each end has two branches connected to the branch channel 202, and the two branches at both ends are connected by a transverse channel.

[0053] In another preferred embodiment, multiple diversion branches 203 form a roughly transverse "H" shape between adjacent diversion branches 202, that is, two diversion branches 203 are connected between the same ellipsoidal circulation channel, and a vertical diversion branch 203 connecting the two transversely connected diversion branches 203 is provided in the middle part of the two transversely connected diversion branches 203.

[0054] With the above configuration, after the modified liquid is injected, it enters each branch channel 202 through the confluence channel 204 and flows in each branch channel 202 at a velocity lower than that of the modified liquid in the confluence channel 204. This allows it to flow towards the confluence channel 204 and the next ellipsoidal annular channel with two branch channels 202, first splitting and then merging through the branch channels 202. Furthermore, while the modified liquid flows in each branch channel 202, the pressure change caused by the velocity difference causes the modified liquid in the branch channels 202 to enter several branch main channels 203, and then flow back or merge back into the corresponding branch channel 202 via the branch main channels 203. In other words, the modified liquid in the branch channels 202 completes secondary splitting and merging through the smaller diameter branch main channels 203.

[0055] Preferably, the branch channels 203 in this invention are mainly for further controlling or improving the flow rate and pressure changes of the modified liquid at each input or output node of the drainage channel. The pressure difference is used to make the modified liquid flow continuously and smoothly inside the drainage channel, so as to guide the modified liquid to flow continuously through and diffuse to the wet gel 100 between the layers of the guide net 200, thereby completing the hydrophobic modification of the wet gel 100 material.

[0056] Example 2

[0057] This embodiment is a further improvement on the basis of embodiment 1. This embodiment focuses on the specific design of the winding device, unwinding device and winding tray 301 of the winding mechanism.

[0058] Preferably, the winding mechanism includes a winding device for alternately winding the wet gel 100 and the flow guide net 200 onto a winding tray 301, and an unwinding device for disassembling the wet gel 100 and the flow guide net 200 after modification. The winding device can alternately wind and wrap the wet gel 100 and the flow guide net 200 filled in the substrate onto the extension shaft 302 of the winding tray 301 by driving the extension shaft 302 arranged on the winding tray 301 to rotate. The unwinding device, after the cyclic modification is completed, drives the extension shaft 302 to rotate in the opposite direction to the winding direction to unwind the wet gel 100 and the flow guide net 200.

[0059] Specifically, the winding mechanism may include a wet gel 100 winding device, a flow guide net 200 winding device, a wet gel 100 unwinding device, and a flow guide net 200 unwinding device. The winding and unwinding of the wet gel 100 and the flow guide net 200 are both completed on the winding tray 301. Specifically, the wet gel 100 and the flow guide net 200 are alternately layered and wound circumferentially around the extension axis 302 of the winding tray 301. In other words, referring to... Figure 3A roll-shaped composite wet gel 100 material, in which unmodified or secondary modified wet gel 100 and flow guide net 200 are alternately rolled up and arranged, can be initially formed on a winding tray 301 using a wet gel 100 winding device and a flow guide net 200 winding device. This roll-shaped composite wet gel 100 material includes wet gel 100 and flow guide net 200 layers rolled up and stacked together. Alternatively, as described above, at least one layer of flow guide net 200 is laid between the wet gel 100 layers.

[0060] Preferably, in the winding state, the circular bottom surface formed by the winding of the wet gel 100 and the flow guide net 200 is placed on the winding tray 301, and the cylindrical structure formed by the winding of the wet gel 100 and the flow guide net 200 is fitted onto the extension shaft 302 extending from the winding tray 301. In particular, the extension shaft 302 on the winding tray 301 is specifically located at the center of the winding tray 301, and the extension shaft 302 is perpendicular to the plane of the winding tray 301, thereby facilitating the winding of the wet gel 100 and the flow guide net 200 onto the winding tray 301.

[0061] Preferably, such as Figure 4 and Figure 5 As shown, both the take-up tray 301 and the extension shaft 302 have several holes 303 on their surfaces that allow the modified liquid to flow through. The take-up tray 301 serves as the connecting base for the extension shaft 302, and the extension shaft 302 is arranged orthogonally to the take-up tray 301. Specifically, during the modification process, the extension shaft 302 can drive the wet gel 100 and the guide net 200 in the entire winding state to rotate. When the modified liquid flows from one end of the wet gel 100 and the guide net 200 in the winding state to the other end, the centrifugal force generated by the rotation will accelerate the flow efficiency of the modified liquid between the layers of the wet gel 100 and the guide net 200. Through the holes 303 provided on the winding tray 301 and the extension shaft 302, it can be fully ensured that the unused modified liquid is removed from the wet gel 100 and the guide net 200 and flows to the bottom of the receiving cavity 304. Then, the pump body configured at the bottom will circulate the unused modified liquid from the bottom of the receiving cavity 304 into the interior of the wet gel 100 and the guide net 200, so as to achieve efficient utilization of the modified liquid.

[0062] Specifically, the shape formed by the winding tray 301 and the extension shaft 302 appears as a "T" shape when viewed from the side.

[0063] Preferably, the wet gel 100 held on the winding tray 301 in the winding state and the guide net 200 are placed in the receiving cavity 304 of the modification mechanism. The modification liquid is drawn from the bottom of the receiving cavity 304 by the pump and injected into the drainage channel of the guide net 200 from the top of the receiving cavity 304 in a preset manner.

[0064] Preferably, the modification mechanism may include a receiving cavity 304 for storing the rolled composite wet gel 100 material formed by the alternating winding of the wet gel 100 and the guide net 200 in the wound state. Specifically, the winding tray 301 for winding the rolled composite wet gel 100 material, together with the wound rolled composite wet gel 100 material, is placed into the receiving cavity 304.

[0065] Preferably, the receiving cavity 304 has a cylindrical structure, with a detachable top cover 305 and a bottom cover 306 at each end. Specifically, the top cover 305 and bottom cover 306 of the receiving cavity 304 can be detachably connected to the tank body using sealing rings and bolts. Specifically, the diameters of the top cover 305 and bottom cover 306 of the receiving cavity 304 are slightly larger than the diameter of the receiving cavity 304 itself. When installing the top cover 305 and bottom cover 306, the sealing rings are first fitted around the openings at both ends of the receiving cavity 304, and then the top cover 305 and bottom cover 306 are connected to the upper and lower ends of the receiving cavity 304 by pressing the sealing rings at the corresponding positions, thereby ensuring that the modified liquid does not leak out during the modification process.

[0066] Specifically, a vent 307 is provided on the top cover 305 at the top of the receiving cavity 304 to connect the inside and outside of the receiving cavity 304, ensuring that the pressure inside the receiving cavity 304 is approximately the same as the external pressure when the top cover 305 and the bottom cover 306 are installed. A liquid outlet 308 is provided on the bottom cover 306 at the bottom of the receiving cavity 304. This liquid outlet 308 has a corresponding control valve. When it is necessary to discharge waste liquid or other liquids from the receiving cavity 304, the control valve of the liquid outlet 308 is opened to discharge the waste liquid.

[0067] Preferably, a pump body interface 310 is also provided on the bottom cover 306 at the bottom of the receiving cavity 304. The pump body interface 310 is mainly located in the center of the bottom cover 306, and the bottom cover 306 is bowl-shaped or other shape structure that can concentrate the liquid inside the bottom cover 306. The pump body structure is used to connect the circulating pump body. The other end of the circulating pipeline 300 connected to the circulating pump body is connected to the liquid injection port 309 of the top cover 305 of the receiving cavity 304. The modified liquid injected from the liquid injection port 309 can perform hydrophobic modification treatment on the rolled composite wet gel 100 material inside the receiving cavity 304. Through the design of the circulating pump body and the circulating pipeline 300, the modified liquid is fully utilized, saving the cost of using the modified liquid and improving production efficiency.

[0068] Specifically, a spraying disc 311 with approximately the same inner diameter as the cavity is provided inside the top cover 305 of the receiving cavity 304. The spraying disc 311 is directly connected to the injection port 309 on the top cover 305. In other words, the modified liquid injected into the injection port 309 needs to be sprayed out from the spraying disc 311 to reach the rolled composite wet gel 100 material. More specifically, the spraying disc 311 is shaped like a shower head. The modified liquid is evenly distributed from the top to the bottom of the rolled composite wet gel 100 material along the extension axis 302 through the shower head-shaped spraying disc 311, and collects at the bottom cover 306 of the receiving cavity 304. The modified liquid collected at the bottom cover 306 is then pumped by the circulation pump into the injection port 309 at the top through the circulation pipeline 300, thereby recycling the modified liquid.

[0069] Preferably, a temperature sensor can be installed inside the receiving cavity 304 to monitor the temperature inside the cavity 304 in real time. A flow controller, flow monitor, or other device can be installed on the circulation pipeline 300 to monitor and control the rate and flow rate of the modified liquid injected into the receiving cavity 304 in real time. Specifically, the flow rate of the circulation pipeline 300 and the circulation pump is preferably 1-30 cubic meters per hour.

[0070] Example 3

[0071] This application also provides a method for secondary modification of aerogel materials, characterized in that a wet gel 100 that has undergone preliminary modification for preparing aerogel materials is provided.

[0072] Specifically, the unmodified wet gel 100 can be non-hydrophobic or partially hydrophobic aerogel glass fiber needle-punched felt, non-hydrophobic or partially hydrophobic aerogel glass fiber surface felt, non-hydrophobic or partially hydrophobic aerogel pre-oxidized fiber needle-punched felt, non-hydrophobic or partially hydrophobic aerogel ceramic fiber felt, etc., and also includes non-hydrophobic or partially hydrophobic aerogel organic open-cell structure foam, such as melamine foam, polyurethane foam, etc.

[0073] Furthermore, the wet gel 100 and the guide net 200 of the modification mechanism are wound onto the winding tray 301 of the winding mechanism in an alternating winding manner and placed inside the receiving cavity 304 of the modification mechanism.

[0074] Furthermore, the modified liquid is injected from the top of the receiving cavity 304 into the drainage channel of the guide net 200, and the modified liquid flowing through the wet gel 100 and the guide net 200 is extracted from the bottom of the receiving cavity 304 by a pump and circulated into the drainage channel of the guide net 200 according to a preset method for secondary modification.

[0075] Furthermore, the winding mechanism winds the wet gel 100 and the flow guide net 200 of the modification mechanism onto the winding tray 301 of the winding mechanism in an alternating winding manner. The wet gel 100 and the flow guide net 200 form several alternately distributed circular layered structures in the winding state. The flow guide net 200 is equipped with a flow channel that can guide the contact mode and contact time of the modification liquid provided by the modification mechanism for secondary modification of the wet gel 100 with the wet gel 100.

[0076] Preferably, the modification of wet gel 100 during the preparation of aerogel materials using a high-efficiency liquid-phase hydrophobic modification method may specifically include the following steps:

[0077] Step 1: Preparation of wet gel 100

[0078] An organosilicon source, ethanol, water, and catalyst are mixed in a specific ratio to obtain precursor solution A. Precursor solution A is brought into full contact with a substrate, and air is removed from the substrate to ensure that precursor solution A completely fills the gaps within the substrate. Furthermore, the precursor solution A filled in the substrate gaps is subjected to an aging treatment to obtain wet gel 100B.

[0079] Step 2: Liquid-phase hydrophobic modification

[0080] The wet gel 100B is unwound and rewound. During the unwound and rewound process, at least one layer of flow guide net 200 is laid between the layers of wet gel 100 material. The wet gel 100 and the flow guide net 200 are simultaneously wound onto the take-up tray 301. The take-up tray 301, which is layered and wound with the wet gel 100 and the flow guide net 200, is placed in the receiving cavity 304. The take-up tray 301 is fully immersed in the receiving cavity 304 using a modification liquid to complete the aerogel modification process.

[0081] Step 3: Supercritical Drying

[0082] The hydrophobically modified wet gel 100 was subjected to supercritical drying to obtain a hydrophobic aerogel composite material.

[0083] Preferably, the ratio of the organosilicon source, ethanol, and water in step one is usually a dynamic ratio.

[0084] Preferably, the substrate described in step one can be one or more of glass fiber needle-punched felt, glass fiber surface felt, pre-oxidized fiber needle-punched felt, and ceramic fiber felt. Alternatively, the substrate can also be an organic open-cell structure foam, such as melamine foam or polyurethane foam.

[0085] Preferably, the aging treatment in step one can be aging at room temperature and pressure. Alternatively, the aging treatment in step one can be accelerated aging at a predetermined temperature.

[0086] Preferably, the liquid phase hydrophobic modification described in step two can be accomplished by the winding device, unwinding device, winding tray 301, guide net 200, liquid phase hydrophobic accommodating cavity 304 and modification circulation pump provided in the winding mechanism and modification mechanism of Examples 1 and 2.

[0087] Preferably, the guide net 200 described in step two can be one or more of nylon net, polyester net, silk net, and cotton yarn net. Further, the guide net 200 can be plain weave net, twill weave net, satin weave net, half-twisted net, or fully twisted net, etc.

[0088] Preferably, the thickness of the flow guide net 200 described in step two is determined based on the actual thickness of the substrate used. In some alternative embodiments, the flow guide net 200 described in step two can be used in multiple layers.

[0089] Preferably, the width of the guide net 200 described in step two should be no less than 85% to 95% of the width of the wet gel 100.

[0090] Preferably, the flow channel for the modified liquid in step two is drawn from the bottom of the receiving cavity 304, transferred to the top of the receiving cavity 304 by a modification pump, and then the modified liquid is uniformly flowed from the upper part to the lower part of the aerogel roll-like product through a "sprinkler" structure. Alternatively, the flow channel for the modified liquid in step two is drawn from the bottom of the receiving cavity 304, transferred to the top of the receiving cavity 304 by a modification pump, injected from the axial part of the wet gel 100, and then returned to the upper part of the wet gel 100 in a "fountain" manner so that the modified liquid is uniformly flowed from the upper part to the lower part of the wet gel 100.

[0091] Preferably, the wet gel 100 described in step two is placed in the receiving cavity 304, and its placement direction must ensure that the flow direction of the guide net 200 is consistent with the flow direction of the modified liquid to ensure the effective flow of the modified liquid.

[0092] Preferably, the modification circulation pump of the modified liquid in step two is kept running throughout the entire hydrophobic modification process to ensure that the flow channel of the modified liquid always follows the flow channel designed by the guide net 200 in Example 1. The modification time is generally 10-50 hours.

[0093] Preferably, the supercritical drying fluid used in step three is carbon dioxide. Technical solutions for supercritical drying fluids have been mentioned in existing technologies, and will not be elaborated upon here.

[0094] It should be noted that the specific embodiments described above are exemplary, and those skilled in the art can devise various solutions inspired by the disclosure of this invention. These solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and not intended to limit the scope of the claims. The scope of protection of this invention is defined by the claims and their equivalents.

Claims

1. A secondary modification system for aerogel materials, characterized in that, include: A winding mechanism is used to perform a lamination and winding process on a wet gel (100) that has been modified to become an aerogel by hydrophobic modification. A modification mechanism for performing secondary modification on the wet gel (100) that has undergone preliminary modification during the preparation process; in, The winding mechanism winds the wet gel (100) and the flow guide net (200) of the modification mechanism onto the horizontally arranged winding tray (301) of the winding mechanism in an alternating winding manner. The wet gel (100) and the flow guide net (200) form several alternating circular hierarchical structures in the winding state. The modification mechanism provides a modification liquid for secondary modification of the wet gel (100). The flow guide net (200) is equipped with a drainage channel, which can improve the contact mode and contact time between the modification liquid and the wet gel (100). In the winding state, the circular bottom surface formed by the winding of the wet gel (100) and the flow guide net (200) is placed on the winding tray (301), and the cylindrical structure formed by the winding of the wet gel (100) and the flow guide net (200) is sleeved on the extension shaft (302) extending from the winding tray (301). The winding tray (301) serves as the connecting base of the extension shaft (302). The guide net (200) is provided with a plurality of main channels (201) along the direction of the extension axis (302). The main channels (201) can guide the modified liquid from the end of the wet gel (100) in the winding state and the guide net (200) away from the winding tray (301) to the end near the winding tray (301).

2. The secondary modification system for aerogel materials according to claim 1, characterized in that, The winding mechanism includes a winding device for alternately winding the wet gel (100) and the flow guide net (200) onto the winding tray (301) and an unwinding device for disassembling the wet gel (100) and the flow guide net (200) after the modification treatment is completed.

3. The secondary modification system for aerogel materials according to claim 1, characterized in that, The winding tray (301) and the extension shaft (302) are both provided with a plurality of holes (303) on their surfaces to allow the modified liquid to flow through, and the extension shaft (302) is arranged orthogonally to the winding tray (301).

4. The secondary modification system for aerogel materials according to claim 2, characterized in that, The winding tray (301) and the extension shaft (302) are both provided with a plurality of holes (303) on their surfaces to allow the modified liquid to flow through, and the extension shaft (302) is arranged orthogonally to the winding tray (301).

5. The secondary modification system for aerogel materials according to any one of claims 1 to 3, characterized in that, On several main channels (201), each main channel (201) has branch channels (202) symmetrically distributed on both sides of the main channel (201).

6. The secondary modification system for aerogel materials according to claim 5, characterized in that, The branch channel (202) extends from the main channel (201) by a predetermined distance in a manner that is connected to each other and then merges into the main channel (201). The diameter of the branch channel (202) is larger than the diameter of the main channel (201).

7. The secondary modification system for aerogel materials according to claim 5, characterized in that, The branch channels (202) symmetrically distributed on both sides of the main channel (201) are connected by a number of branch channels (203). The diameter of the branch channels (203) is smaller than the diameter of the branch channels (202) and / or the main channel (201). The main channels (201) are spaced apart from each other, and the branch channels (202) are distributed within the intervals between the main channels (201).

8. The secondary modification system for aerogel materials according to any one of claims 1 to 3, characterized in that, The wet gel (100) held on the winding tray (301) in the winding state and the guide net (200) are placed in the receiving cavity (304) of the modification mechanism. The modification liquid is drawn from the bottom of the receiving cavity (304) to the circulation pipeline (300) connected to the main body by the pump and injected into the drainage channel of the guide net (200) from the top of the receiving cavity (304) in a preset manner.

9. A method for secondary modification of aerogel materials, characterized in that, The secondary modification method is performed using the secondary modification system described in any one of claims 1 to 8, and includes: Provides a pre-modified wet gel (100) for the preparation of aerogel materials; The wet gel (100) and the guide net (200) of the modification mechanism are wound onto the winding tray (301) of the winding mechanism in an alternating winding manner and placed inside the receiving cavity (304) of the modification mechanism. The modified liquid is injected from the top of the receiving cavity (304) into the drainage channel of the guide net (200), and the modified liquid flowing through the wet gel (100) and the guide net (200) is extracted from the bottom of the receiving cavity (304) by a pump and circulated into the drainage channel of the guide net (200) according to a preset method for secondary modification; The winding mechanism winds the wet gel (100) and the flow guide net (200) of the modification mechanism onto the winding tray (301) of the winding mechanism in an alternating winding manner. The wet gel (100) and the flow guide net (200) form several alternating circular layered structures in the winding state. The modification mechanism provides a modification liquid for secondary modification of the wet gel (100). The flow guide net (200) is equipped with a drainage channel, which can improve the contact mode and contact time of the modification liquid with the wet gel (100).

Images