A method of pre-treating a glass needle-punched felt substrate for aerogels

Abstract

The application discloses a kind of pre-treatment methods of glass needle felt substrate for aerogel, specifically comprising the following steps: first, lay multiple layers of glass fiber to form a first glass fiber layer, then evenly spray inorganic powder on top of the first glass fiber layer to form an inorganic powder layer, and then lay multiple layers of glass fiber on top of the inorganic powder layer to form a second glass fiber layer, forming a glass needle felt substrate with a sandwich structure; finally, immerse the glass needle felt substrate in an aerogel solution for soaking to obtain an aerogel glass fiber material.

Description

Technical Field

[0001] This invention relates to the field of aerogel materials technology, and more specifically to a pretreatment method for aerogel glass needle-punched felt substrate. Background Technology

[0002] Aerogel materials are composite materials, typically using glass fiber needled mat as their important physical support framework to improve their mechanical properties. Existing technologies often incorporate different types and proportions of powders or granules into aerogel materials to enhance their physical and chemical properties.

[0003] Current technologies typically involve adding powders or granules to the aerogel solution during the formulation stage, along with the addition of additives to improve dispersion. However, this process significantly increases the difficulty of mixing during production. Furthermore, the presence of solids in the solution makes it prone to clogging pipes, causing production stoppages and greatly increasing the workload and costs of unclogging pipes. Additionally, some powders or granules disperse poorly in the solution, resulting in inconsistent color and poor appearance uniformity in the aerogel product. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a pretreatment method for glass needle-punched felt substrate for aerogel, so as to solve the problems in the prior art that adding powder or particulate matter to aerogel liquid can easily lead to blockage of material conveying pipes, affect continuous production, and result in poor dispersion of powder or particulate matter in the liquid system and inconsistent product surface color.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A pretreatment method for aerogel glass needle-punched mat substrate specifically includes the following steps:

[0007] First, multiple layers of glass fiber are laid to form a first glass fiber layer. Then, inorganic powder is evenly sprayed on top of the first glass fiber layer to form an inorganic powder layer. Next, multiple layers of glass fiber are laid on top of the inorganic powder layer to form a second glass fiber layer, thus forming a glass needle-punched felt substrate with a sandwich structure. Finally, the glass needle-punched felt substrate is immersed in aerogel solution to obtain aerogel glass fiber material.

[0008] Preferably, the thickness ratio of the first glass fiber layer, the inorganic powder layer, and the second glass fiber layer is (1-3):(2-4):(1-3).

[0009] Preferably, the inorganic powder includes one or more of metal oxide powder, mineral powder, graphite powder, and silicon compound powder.

[0010] Preferably, the particle size of the inorganic powder is 2nm-200um.

[0011] Preferably, the thickness of the glass fiber is 5mm-40mm.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] 1. The pretreatment method of the present invention first lays glass fibers, then sprinkles in inorganic powder, and then lays in glass fibers again to form a three-layer sandwich structure before impregnating with aerogel adhesive. By uniformly sprinkling inorganic powder between the glass fiber layers, the filling density of the composite material can be increased, and its thermal stability and mechanical strength can be improved. The impregnation with aerogel adhesive can ensure that the entire composite system has good thermal insulation performance. This treatment method can fundamentally solve the problem of blockage in the adhesive conveying pipeline, and can also ensure that the flow rate of adhesive in the conveying pipeline is uniform and stable, thereby ensuring the gelation effect and solving the problem of abnormal product quality.

[0014] 2. The pretreatment method described in this invention can ensure that the product appearance color is completely consistent and there is no risk of excessive accumulation of powder on the product surface; moreover, since no powder or particulate matter is added to the aerogel solution, the solidification process of the aerogel solution will not be interfered with by other substances, which is very helpful for the growth and molding of the aerogel. Attached Figure Description

[0015] Figure 1 The images show cross-sectional views of the aerogel products prepared in Example 1 and Comparative Example 1; where a represents Example 1 and b represents Comparative Example 1. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the present invention are within the scope of protection of the present invention.

[0017] Unless otherwise specified in the specific circumstances, the numerical ranges listed herein include upper and lower limits, as well as all integers and fractions within that range, but are not limited to the specific values ​​listed when the range is defined.

[0018] I. A pretreatment method for aerogel glass needle-punched mat substrate

[0019] The specific steps of the pretreatment method described in this invention are as follows: First, multiple layers of glass fibers are laid to form a first glass fiber layer, using glass fiber fabric or mesh structure as the base layer of the composite material to provide structural support and enhance mechanical strength. Then, inorganic powder is uniformly sprayed on top of the first glass fiber layer to form an inorganic powder layer, allowing the inorganic powder to be evenly spread on top of the first glass fiber layer to increase the material's filling density and thermal stability. Next, multiple layers of glass fibers are laid on top of the inorganic powder layer to form a second glass fiber layer, forming a glass needle-punched felt substrate with a sandwich structure. Finally, the glass needle-punched felt substrate is immersed in an aerogel solution for soaking, allowing the aerogel solution components to penetrate and fill the gaps between the glass fibers and the inorganic powder. Subsequently, drying and supercritical or atmospheric pressure drying are performed to remove the solvent and solidify, obtaining the aerogel material.

[0020] In the actual production of aerogel materials, this invention found that existing technologies add target powders or particles during the aerogel preparation stage. However, this undoubtedly increases the difficulty of mixing in the preparation process. Due to the viscosity of the aerogel, it is very difficult to achieve uniform mixing of the target powders or particles. Even with the addition of dispersants, although the mixing difficulty can be improved to some extent, it affects the stability of the aerogel system, thus impacting aerogel growth and molding. Moreover, this mixing method also makes the aerogel with added target powders or particles prone to clogging the conveying pipes. This not only interrupts the production process but also requires workers to clear the pipes, further affecting the smoothness of the production process. Furthermore, the flow rate of the aerogel becomes very unstable after the pipes are clogged, resulting in poor gelation of the aerogel and ultimately leading to product quality problems and an increase in the number of defective products. Therefore, when initially conceiving a solution to this technical problem, the present invention attempted to address it by changing the stirring speed, adding other dispersants or additives, etc., but the results were unsatisfactory. These methods still could not fundamentally solve the problems of pipe blockage and unstable product quality. Therefore, the present invention changed its approach, starting with changing the pretreatment of the glass needle-punched felt substrate. The present invention adopts a treatment method of first laying glass fibers, then sprinkling inorganic powder, and then laying glass fibers again to form a three-layer sandwich structure. This allows the inorganic powder to be added separately from the aerogel adhesive, which can fundamentally solve the problem of pipe blockage. Subsequently, this substrate with a sandwich structure is immersed in the aerogel adhesive. Through the fluidity of the aerogel adhesive, the adhesive can fully fill the interior of the substrate while also carrying the inorganic powder to fully penetrate into the interior of the glass fiber material. By adding inorganic powder between the glass fiber layers, the filling density of the composite material can be increased, improving its thermal stability and mechanical strength; while the wetting of the aerogel adhesive ensures that the entire composite system has good thermal insulation performance. Most importantly, this pretreatment method not only achieves thorough mixing of inorganic powder and aerogel, improving the physical and chemical properties of the aerogel, but also ensures stable product quality, preventing any impact on the growth and formation of the aerogel colloid and guaranteeing a completely consistent product appearance and color. Furthermore, after laying the second glass fiber layer, it undergoes high-frequency needle punching to form a glass needle-punched mat. When the powder is evenly sprinkled into the intermediate layer of the substrate, the subsequent high-frequency needle punching process ensures that some of the powder is evenly dispersed throughout the substrate, allowing for more effective and uniform adhesion of the powder to the glass fiber surface and between layers. Because no powder is added to the adhesive, the viscosity is reduced, resulting in higher impregnation efficiency and preventing incomplete impregnation. This is especially important for samples larger than 10mm, where increased powder content and higher viscosity make thorough impregnation more difficult, potentially leading to substandard product quality.

[0021] In some embodiments, the thickness ratio of the first glass fiber layer, the inorganic powder layer, and the second glass fiber layer is (1-3):(2-4):(1-3). Depending on the product characteristics, the powder addition amount is typically controlled between 200g and 2000g / m³. 3 The amount of powder added will vary depending on the thickness of the product substrate. Under normal circumstances, the thickness of the inorganic powder layer formed after the powder is added is proportional to the overall thickness of the substrate. The powder adding process has high requirements for the powder adding mechanical system and requires regular cleaning. At the same time, selecting a suitable sieve can effectively prevent the addition of large particles from causing abnormalities.

[0022] In some embodiments, the inorganic powder includes one or more of metal oxide powder, mineral powder, graphite powder, and silicon compound powder.

[0023] In some embodiments, the particle size of the inorganic powder is 2 nm to 200 μm. The particle size of the inorganic powder should not be too small, as this can easily lead to agglomeration of the inorganic powder during adhesive impregnation; however, it should not be too large either, as this will make it difficult for the inorganic powder to penetrate into the glass fiber layer.

[0024] In some embodiments, the thickness of the single-layer glass fiber is 5mm-40mm. The thickness of the single-layer glass fiber is usually adjusted according to the overall thickness of the aerogel material, but it should not be too thin. If it is too thin, it will cause too much damage to the glass fiber during the needle punching process, while if it is too thick, the diffusion effect of inorganic powder in the single-layer glass fiber will be poor during the aerogel wetting process. The diameter of the glass fiber is usually controlled to be <10μm, or greater than 5μm and less than 10μm, because very fine fibers may pose a carcinogenic risk. To consider structural strength, this invention takes into account the longitudinal structure of the substrate, and can appropriately increase the needle punching reinforcing ribs to improve structural strength.

[0025] II. Examples and Comparative Examples

[0026] Example 1

[0027] First, multiple layers of glass fiber are laid to form the first glass fiber layer, using glass fiber fabric or mesh structure as the base layer of the composite material to provide structural support and enhance mechanical strength. Then, inorganic powder is uniformly sprayed onto the first glass fiber layer to form an inorganic powder layer, ensuring the inorganic powder is evenly distributed above the first glass fiber layer to increase the material's packing density and thermal stability. Next, multiple layers of glass fiber are laid on top of the inorganic powder layer to form the second glass fiber layer, creating a glass fiber substrate with a sandwich structure. This substrate is then subjected to high-frequency needle punching to ultimately form a glass needle-punched felt substrate with a sandwich structure. Finally, the glass needle-punched felt substrate is immersed in an aerogel solution, allowing the aerogel components to penetrate and fill the gaps between the glass fibers and inorganic powder. It is then dried using supercritical or atmospheric pressure drying to remove the solvent and cure, yielding the aerogel material. The thickness ratio of the first glass fiber layer, the inorganic powder layer, and the second glass fiber layer is 1:2:1. The thickness of a single glass fiber layer is 5 mm. The inorganic powder is calcium oxide, and the average particle size of the inorganic powder is controlled between 2 and 100 μm. The aerogel solution used is silica aerogel solution.

[0028] Example 2

[0029] The following adjustments were made based on Example 1, with the following differences: the thickness ratio of the first glass fiber layer, the inorganic powder layer, and the second glass fiber layer is 2:2:2, the thickness of a single glass fiber layer is 15 mm, the inorganic powder is artificial graphite, and the average particle size of the inorganic powder is controlled between 5 and 100 nm.

[0030] Example 3

[0031] The adjustment is based on Example 1, with the following differences: the thickness ratio of the first glass fiber layer, the inorganic powder layer and the second glass fiber layer is 3:4:3, the thickness of a single glass fiber layer is 40 mm, the inorganic powder is a mixture of iron oxide and magnesium oxide powder, and the average particle size of the inorganic powder is controlled between 2 and 15 μm.

[0032] Comparative Example 1

[0033] The raw materials used are exactly the same as those in Example 1. The difference is that the inorganic powder is first mixed with the silica aerogel liquid, and then transported to the glass fiber to impregnate it to obtain the aerogel material.

[0034] After the production lines corresponding to the example and the comparative example have each been running for one month:

[0035] The production lines corresponding to Examples 1-3 can continuously produce. Since no inorganic powder is added to the aerogel liquid, the aerogel liquid delivery pipeline of the examples has never been blocked. Moreover, the products obtained in the examples have a consistent surface color, the aerogel is thoroughly and fully impregnated, the aerogel colloid forming effect is very good, and multiple batches of products can be produced smoothly with stable product quality and no product quality abnormalities have occurred.

[0036] In contrast, after producing several batches of products, the quality of Comparative Example 1 first fluctuated, the surface color of the products became inconsistent, and the aerogel molding effect was significantly worse than that of the Example. Abnormal product quality began to appear. Subsequently, less than a month after operation, the aerogel liquid delivery pipeline became blocked, requiring a shutdown for unblocking.

[0037] A comparison of the mechanical properties of the aerogel product prepared in the examples and the qualified aerogel product prepared in Comparative Example 1 shows that the aerogel product prepared in the examples has superior mechanical properties compared to the qualified aerogel product prepared in Comparative Example 1. Figure 1 As can be seen, the aerogel product obtained in the examples exhibits more thorough wetting of the aerogel solution. The fluidity of the aerogel solution allows it to fully fill the substrate while also carrying inorganic powder deep into the glass fiber material. Adding inorganic powder between the glass fiber layers increases the filling density of the composite material, improving its thermal stability and mechanical strength. In contrast, the aerogel product prepared in Comparative Example 1 shows less thorough wetting than the examples, resulting in significantly inferior mechanical properties and thermal stability.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A pretreatment method for aerogel glass needle-punched felt substrate, characterized in that, Specifically, the steps include the following: First, multiple layers of glass fiber are laid to form a first glass fiber layer. Then, inorganic powder is evenly sprayed on top of the first glass fiber layer to form an inorganic powder layer. Next, multiple layers of glass fiber are laid on top of the inorganic powder layer to form a second glass fiber layer, forming a glass fiber substrate with a sandwich structure. Subsequently, it is subjected to high-frequency needle punching to form a glass needle-punched felt substrate with a sandwich structure. Finally, the glass needle-punched felt substrate is immersed in aerogel solution to obtain aerogel glass fiber material.

2. The pretreatment method according to claim 1, characterized in that, The thickness ratio of the first glass fiber layer, the inorganic powder layer, and the second glass fiber layer is (1~3):(2~4):(1~3).

3. The preprocessing method according to claim 1, characterized in that, The inorganic powder includes one or more of the following: metal oxide powder, mineral powder, graphite powder, and silicon compound powder.

4. The pretreatment method according to claim 1, characterized in that, The inorganic powder has a particle size of 2nm-200um.

5. The pretreatment method according to claim 1, characterized in that, The thickness of a single layer of glass fiber ranges from 5mm to 40mm.

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