A multilayer glass fiber insulation board and a process for preparing the same

Abstract

The present application relates to the technical field of heat insulation board, in particular to a kind of multilayer glass fiber heat insulation board and its preparation process.The following scheme is specifically proposed:S1: preparation of hyperdispersant, first modified nano-silica, then melt extrusion with polyethylene terephthalate by single screw extruder, to obtain resin sheet;S2: glass fiber and aramid fiber are added to dispersion liquid and mixed evenly, after dehydration, by opening, mixing cotton, carding, laying and sewing treatment, to obtain glass / aramid fiber felt;S3: resin sheet and glass / aramid fiber felt are cross-laminated, stacked to the required number of layers, after cutting, hot welding, to obtain multilayer core material, then sewing treatment, finally packaging, vacuum, to obtain multilayer glass fiber heat insulation board.Through the modification of resin sheet and the composite of fiber felt, the resin sheet and fiber felt are cross-laminated, and finally sewing treatment is carried out, to obtain the heat insulation board with excellent heat insulation performance.

Description

Technical Field

[0001] This invention relates to the field of insulation board technology, specifically to a multi-layer glass fiber insulation board and its preparation process. Background Technology

[0002] Vacuum insulation panels are a type of highly efficient heat insulation material with excellent thermal insulation performance. They are composed of a core material and a vacuum-protected surface layer, effectively preventing heat transfer caused by convection, thus significantly reducing the thermal conductivity to 1 / 10 that of traditional insulation materials. Currently, vacuum insulation panels are being used in industries such as refrigerators, refrigeration, and construction. Their excellent thermal insulation properties bring environmental and energy-saving advantages, resulting in significant economic benefits, and the market prospects for vacuum insulation panels are very broad.

[0003] However, currently produced vacuum insulation panels generally use a single material as the core, such as glass fiber, phenolic resin, or polyurethane. Single-material panels inevitably have some defects, preventing the insulation panels from achieving ideal thermal insulation performance. Furthermore, even when using multi-layered core materials, the common technique is hot-melt bonding, which, due to compatibility issues, doesn't ensure good adhesion between the materials. Over time, the bonding strength between the different materials decreases, affecting the insulation performance.

[0004] In summary, the present invention will prepare a multilayer glass fiber insulation board to solve the above-mentioned problems, so that vacuum insulation boards can be more widely used and have a better market prospect. Summary of the Invention

[0005] The purpose of this invention is to provide a multilayer glass fiber insulation board and its preparation process to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] S1: To prepare a superdispersant, first modify nano-silica, then melt-extrude it with polyethylene terephthalate using a single-screw extruder to obtain resin sheets;

[0008] Furthermore, the preparation method of the superdispersant is as follows: N-vinylacetamide, maleic anhydride and tris(2-acryloyloxyethyl)isocyanurate are added to sufficient toluene and stirred to dissolve them. The solution is then evenly divided into two portions, A and B. Solution A is heated to 50-70°C, and an appropriate amount of azobisisobutyronitrile is added to solution A. The mixture is stirred and reacted for 30-60 minutes. While maintaining the reaction temperature, solution B is added dropwise to solution A at a rate of 10-30 drops / min. After solution B has been added, the mixture is allowed to stand for 1-2 hours. Finally, the mixture is filtered, washed, and dried to obtain the superdispersant.

[0009] Furthermore, the mass ratio of N-vinylacetamide, maleic anhydride, and tris(2-acryloyloxyethyl)isocyanurate is 10:12:17, and the amount of azobisisobutyronitrile added is 0.5 to 1.2% of the mass of N-vinylacetamide.

[0010] Furthermore, the nano-silica modification process is as follows: the nano-silica is preheated to 100-110°C in an open environment and stirred at a speed of 100-200 r / min for 10-15 min; the temperature is adjusted to 80-100°C, and the superdispersant is slowly added to the nano-silica and stirred at a speed of 400-800 r / min for 10-20 min to obtain modified silica.

[0011] Furthermore, the mass ratio of the nano-silica to the superdispersant is 10:(0.5-1.2).

[0012] Furthermore, the compression ratio of the single-screw extruder is 2.5:1 to 3.5:1, and the melt extrusion temperature is 245 to 265°C.

[0013] Furthermore, the thickness of the resin sheet is 0.04–2 mm.

[0014] Furthermore, the percentage of each component in the resin sheet is as follows: polyethylene terephthalate 87-95%, modified silica 5-13%.

[0015] The superdispersant prepared above can greatly improve the compatibility between inorganic particles and resin, and prevent inorganic particles from agglomerating, thus dispersing them well in the resin material. This results in the modified resin having better thermal insulation properties. Simultaneously, amide and isocyanuric acid groups were introduced during the preparation process. Isocyanuric acid groups can effectively reduce the thermal conductivity of the resin sheet. However, since isocyanuric acid groups begin to decompose at around 270℃, the introduction of amide groups can improve the thermal stability of the superdispersant, preventing decomposition of isocyanuric acid groups during melt extrusion. This fully ensures the role of the superdispersant in the resin sheet, thereby guaranteeing the thermal insulation performance of the resin sheet. Silica is selected as the filler. Silica is an excellent refractory material with excellent thermal insulation properties and thermal stability. Nano-silica is chosen because its small particle size, large specific surface area, and numerous surface-active functional groups make it more compatible with the resin material. Under the action of the superdispersant, the overall effect is to further enhance the thermal insulation performance of the resin sheet.

[0016] S2: Glass fiber and aramid fiber are added to the dispersion and mixed evenly. After dehydration, they are opened, mixed, carded and laid into a web and sewn to obtain glass / aramid fiber felt.

[0017] Furthermore, the dispersion is composed of deionized water, thickener and superdispersant prepared in S1, with a mass ratio of 10:(0.2-0.4):(0.4-1).

[0018] Furthermore, the amount of the dispersion added is 2.5% to 5% of the mass of the glass fiber and aramid fiber.

[0019] Furthermore, the glass fiber has a length of 15–20 mm and a diameter of φ5–10 μm; the aramid fiber has a length of 8–12 mm and a diameter of φ10–20 μm; and the mass ratio of glass fiber to aramid fiber is 6:4.

[0020] Furthermore, the cotton blending is a tumbling blending process, and the blending time is 30 to 60 minutes.

[0021] Furthermore, the combed web is a cross-laid web, and each layer of web is reinforced with hydroentangling at a pressure of 200-400 MPa until the fiber web thickness reaches 0.04-5 mm, and finally dehydrated and dried at 100-110°C.

[0022] Furthermore, the sewing process involves cross-sewing with meta-aramid thread at intervals of 6-8 cm and row spacing.

[0023] The aforementioned glass / aramid fiber mat is made by blending glass fiber and aramid fiber. Glass fiber mat made from a single glass fiber is too brittle and easily broken, making subsequent sewing difficult. Furthermore, a single glass fiber material cannot produce a fiber mat with optimal thermal insulation performance. Aramid fiber has high strength and high modulus, resulting in excellent thermal insulation performance, but its compressive strength is poor, making it unsuitable for multi-layer insulation boards. Therefore, a blend of glass fiber and aramid fiber is used to achieve high thermal insulation performance and better processing performance. Since meta-aramid fiber has better thermal insulation performance than para-aramid fiber, meta-aramid fiber is used in this invention. Further processing, including opening, blending, carding, web laying, and sewing, ensures that the glass fiber and aramid fiber are more evenly dispersed, making the glass / aramid fiber mat more stable and compact, thus improving the thermal insulation performance of the fiber mat.

[0024] S3: The resin sheet and glass / aramid fiber felt are cross-layered and stacked to the required number of layers. After cutting and heat-fusion, a multi-layer core material is obtained. Then, it is sewn and finally packaged and vacuumed to obtain a multi-layer glass fiber insulation board.

[0025] Furthermore, the cross-lamination is as follows: if the first layer is a resin sheet, the second layer is a glass / aramid fiber felt, the third layer is a resin sheet, and so on, cross-lamination is performed until the required number of layers is reached.

[0026] Furthermore, the hot-melt welding is performed by heating the stacked resin sheets and glass / aramid fiber felt to 240-250°C and applying a certain pressure to compress them to 85-87% of their original thickness, thereby obtaining a multilayer core material.

[0027] Furthermore, the sewing process is as follows: using meta-aramid sewing thread, sew from one corner of the multilayer core material to the adjacent corner, and then sew the remaining adjacent corners in sequence until all four corners are sewn to the adjacent corners; then sew along the two diagonals of the multilayer core material; finally, cross-sewing is performed at a spacing of 4-5 cm.

[0028] Furthermore, the processing procedure for the multi-layer glass fiber insulation board is as follows: the sewn multi-layer core material is placed into a composite aluminum film bag, the vacuum heat sealing machine is set to a vacuum degree of 0.1 Pa, and the pressure is maintained for a delay of 5 to 10 minutes to obtain the multi-layer glass fiber insulation board.

[0029] The above-mentioned method uses a cross-laminated resin sheet and glass / aramid fiber felt, which improves the mechanical properties of the insulation core material compared to single-material lamination, and provides better selectivity and processability. The material is first heat-fused and then sewn. If only heat-fused, cracking and delamination are likely to occur as the adhesive ages, ultimately reducing insulation performance. Sewing provides some fixation for the core material, preventing severe delamination and significant impact on insulation performance even during aging. Without heat-fused bonding, the adhesion between the resin sheet and fiber felt is insufficient, inevitably leading to some degree of delamination. This results in the insulation board not achieving the ideal internal vacuum level, affecting its insulation performance.

[0030] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The present invention prepares a super-dispersant during the preparation of the resin sheet, which improves the dispersion and compatibility of inorganic particles, while introducing isocyanuric acid groups, greatly reducing the thermal conductivity of the resin sheet and enhancing its thermal insulation performance; in the preparation of the fiber felt, glass fiber and meta-aramid fiber are used in combination to obtain a fiber felt with excellent processing and thermal insulation properties; the resin sheet and fiber felt are cross-laminated to give it better mechanical properties and also make the core material more selectively processable; to prevent the performance of the insulation board from significantly declining with the aging of the adhesive, it is sewn, finally resulting in an insulation board with excellent comprehensive performance. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] In the following examples, N-vinylacetamide had a purity of 98% (CAS No.: 5202-78-8, Shanghai Yuanye Biotechnology Co., Ltd.); maleic anhydride had a purity of 99% (Hebei Guanlang Biotechnology Co., Ltd.); tris(2-acryloyloxyethyl)isocyanurate had a purity of 98% (CAS No.: 40220-08-4, catalog number: TF-27141, Henan Tianfu Chemical Co., Ltd.); toluene had a purity of 99.99% (Nanjing Runsheng Petrochemical Co., Ltd.); azobisisobutyronitrile (AIBN) had a purity of 99% (Henan Tianfu Chemical Co., Ltd.); and nano-dioxide... Silicon purity 99.5%, particle size 7-20nm (Hubei Jusheng Technology Co., Ltd.); glass fiber purity 99.5%, length 15-20mm, diameter φ5-10μm (Hubei Jusheng Technology Co., Ltd.); meta / para aramid fiber purity 99%, length 8-12mm, diameter φ10-20μm (Zhangjiagang Yudun Special Fiber Co., Ltd.); PU-40 thickener (Qingdao Enze Chemical Co., Ltd.); calcium stearate purity 99%, CAS No.: 1592-23-0 (Hebei Mojin Biotechnology Co., Ltd.).

[0033] Example 1: A manufacturing process for a multilayer glass fiber insulation board, comprising the following steps:

[0034] S1: Preparation method of superdispersant: 30 parts of N-vinylacetamide, 36 parts of maleic anhydride and 51 parts of tris(2-acryloyloxyethyl)isocyanurate were added to 100 parts of toluene and stirred to dissolve. The solution was then divided into two parts, A and B. Solution A was heated to 60°C. Then, 0.33 parts of azobisisobutyronitrile were added to solution A and the mixture was stirred for 40 min. While maintaining the reaction temperature, solution B was added dropwise to solution A at a rate of 15 drops / min. After solution B was completely added, the mixture was allowed to stand for 2 h. Finally, the mixture was filtered, washed and dried to obtain the superdispersant.

[0035] Nano silica modification process: 30 parts of nano silica were preheated to 105℃ in an open container and stirred at 100r / min for 15min; the temperature was adjusted to 90℃, and 3 parts of superdispersant were slowly added to the nano silica and stirred at 550r / min for 15min to obtain modified silica.

[0036] Finally, the modified silica and polyethylene terephthalate were melt-extruded using a single-screw extruder to obtain resin sheets. The compression ratio of the single-screw extruder was 3.0:1, and the melt extrusion temperature was 255℃.

[0037] The percentage of each component in the resin sheet is as follows: 150 parts polyethylene terephthalate and 15 parts modified silica; the thickness of the resin sheet is 1 mm.

[0038] S2: (1) Mix 20 parts of deionized water, 0.6 parts of PU-40 thickener and 1.2 parts of superdispersant evenly to obtain a dispersion;

[0039] (2) Take 120 parts of glass fiber with a length of 18mm and a diameter of φ5mm, 80 parts of meta-aramid fiber with a length of 12mm and a diameter of φ10μm, and 9 parts of dispersion liquid and mix them evenly. After dehydration, the mixture is opened and mixed with cotton for 60 minutes in sequence, and then cross-laid. Each layer of the web is reinforced with hydroentangling at a pressure of 400Mpa until the fiber web thickness reaches 3mm. Finally, it is dehydrated and dried at 105℃.

[0040] (3) Then use meta-aramid sewing thread to cross-sew at a spacing of 7cm and row spacing to obtain glass / aramid fiber mat.

[0041] S3: The first layer is a resin sheet, the second layer is a glass / aramid fiber felt, and the third layer is a resin sheet. These layers are stacked in a cross-layered manner, for a total of 11 layers. The thickness of the multi-layer core material is 23mm. It is heat-fused at 245℃ and pressure is applied to obtain a 20mm thick thermal insulation core material.

[0042] The sewing process is as follows: use meta-aramid sewing thread to sew from one corner of the multi-layer core material to the adjacent corner, and sew the remaining adjacent corners in sequence until all four corners are sewn to the adjacent corners; then sew along the two diagonals of the multi-layer core material; finally, cross-sew with a spacing of 4cm between rows.

[0043] The processing procedure for multi-layer glass fiber insulation board is as follows: the sewn multi-layer core material is placed into a composite aluminum film bag, the vacuum heat sealing machine is set to a vacuum degree of 0.1 Pa, and the pressure is maintained for 10 minutes to obtain the multi-layer glass fiber insulation board.

[0044] Example 2: A manufacturing process for a multilayer glass fiber insulation board, comprising the following steps:

[0045] S1: Preparation method of superdispersant: 30 parts of N-vinylacetamide, 36 parts of maleic anhydride and 51 parts of tris(2-acryloyloxyethyl)isocyanurate were added to 100 parts of toluene and stirred to dissolve. The solution was then divided into two parts, A and B. Solution A was heated to 50°C, and 0.15 parts of azobisisobutyronitrile were added to solution A and stirred for 30 min. While maintaining the reaction temperature, solution B was added dropwise to solution A at a rate of 10 drops / min. After solution B was completely added, the solution was allowed to stand for 1 h. Finally, the solution was filtered, washed and dried to obtain the superdispersant.

[0046] Nano silica modification process: 30 parts of nano silica were preheated to 105℃ in an open container and stirred at 100r / min for 15min; the temperature was adjusted to 80℃, and 1.5 parts of superdispersant were slowly added to the nano silica and stirred at 400r / min for 15min to obtain modified silica.

[0047] Finally, the modified silica and polyethylene terephthalate were melt-extruded using a single-screw extruder to obtain resin sheets. The compression ratio of the single-screw extruder was 2.5:1, and the melt extrusion temperature was 245℃.

[0048] The percentage of each component in the resin sheet is as follows: 150 parts polyethylene terephthalate and 15 parts modified silica; the thickness of the resin sheet is 1 mm.

[0049] S2: (1) Mix 20 parts of deionized water, 0.4 parts of PU-40 thickener and 0.8 parts of superdispersant evenly to obtain a dispersion;

[0050] (2) Take 120 parts of glass fiber with a length of 15mm and a diameter of φ10mm, 80 parts of meta-aramid fiber with a length of 8mm and a diameter of φ20μm, and mix them evenly with 5 parts of dispersion liquid. After dehydration, the mixture is opened and mixed with cotton for 30 minutes in sequence, and then cross-laid. Each layer of the web is reinforced with hydroentangling at a pressure of 200Mpa until the fiber web thickness reaches 3mm. Finally, it is dehydrated and dried at 105℃.

[0051] (3) Then use meta-aramid sewing thread to cross-sew at a spacing of 7cm and row spacing to obtain glass / aramid fiber mat.

[0052] S3: The first layer is a resin sheet, the second layer is a glass / aramid fiber felt, and the third layer is a resin sheet. These layers are stacked in a cross-layered manner, for a total of 11 layers. The thickness of the multi-layer core material is 23mm. It is heat-fused at 240℃ and pressure is applied to obtain a 20mm thick thermal insulation core material.

[0053] The sewing process is as follows: use meta-aramid sewing thread to sew from one corner of the multilayer core material to the adjacent corner, and sew the remaining adjacent corners in sequence until all four corners are sewn to the adjacent corners; then sew along the two diagonals of the multilayer core material; finally, cross-sew at a spacing of 5cm between rows.

[0054] The processing procedure for multi-layer glass fiber insulation board is as follows: the sewn multi-layer core material is placed into a composite aluminum film bag, the vacuum heat sealing machine is set to a vacuum degree of 0.1 Pa, and the pressure is maintained for 5 minutes to obtain the multi-layer glass fiber insulation board.

[0055] Example 3: A manufacturing process for a multilayer glass fiber insulation board, comprising the following steps:

[0056] S1: Preparation method of superdispersant: 30 parts of N-vinylacetamide, 36 parts of maleic anhydride and 51 parts of tris(2-acryloyloxyethyl)isocyanurate were added to 100 parts of toluene and stirred to dissolve. The solution was then divided into two parts, A and B. Solution A was heated to 70°C. Then, 0.42 parts of azobisisobutyronitrile were added to solution A and the mixture was stirred for 60 min. While maintaining the reaction temperature, solution B was added dropwise to solution A at a rate of 30 drops / min. After solution B was completely added, the mixture was allowed to stand for 2 h. Finally, the mixture was filtered, washed and dried to obtain the superdispersant.

[0057] Nano silica modification process: 30 parts of nano silica were preheated to 105℃ in an open container and stirred at 100r / min for 15min; the temperature was adjusted to 100℃, and 4.2 parts of superdispersant were slowly added to the nano silica and stirred at 800r / min for 20min to obtain modified silica.

[0058] Finally, the modified silica and polyethylene terephthalate were melt-extruded using a single-screw extruder to obtain resin sheets. The compression ratio of the single-screw extruder was 3.5:1, and the melt extrusion temperature was 265℃.

[0059] The percentage of each component in the resin sheet is as follows: 150 parts polyethylene terephthalate and 15 parts modified silica; the thickness of the resin sheet is 1 mm.

[0060] S2: (1) Mix 20 parts of deionized water, 0.8 parts of PU-40 thickener and 2 parts of superdispersant evenly to obtain a dispersion;

[0061] (2) Take 120 parts of glass fiber with a length of 20mm and a diameter of φ7mm, 80 parts of meta-aramid fiber with a length of 12mm and a diameter of φ13μm, and mix them evenly with 10 parts of dispersion liquid. After dehydration, the mixture is opened and mixed with cotton for 40 minutes in sequence, and then cross-laid. Each layer of the web is reinforced with hydroentangling at a pressure of 300Mpa until the fiber web thickness reaches 3mm. Finally, it is dehydrated and dried at 105℃.

[0062] (3) Then use meta-aramid sewing thread to cross-sew at a spacing of 7cm and row spacing to obtain glass / aramid fiber mat.

[0063] S3: The first layer is a resin sheet, the second layer is a glass / aramid fiber felt, and the third layer is a resin sheet. These layers are stacked in a cross-layered manner, for a total of 11 layers. The thickness of the multi-layer core material is 23mm. It is heat-fused at 250℃ and pressure is applied to obtain a 20mm thick thermal insulation core material.

[0064] The sewing process is as follows: use meta-aramid sewing thread to sew from one corner of the multilayer core material to the adjacent corner, and sew the remaining adjacent corners in sequence until all four corners are sewn to the adjacent corners; then sew along the two diagonals of the multilayer core material; finally, cross-sew at a spacing of 5cm between rows.

[0065] The processing procedure for multi-layer glass fiber insulation board is as follows: the sewn multi-layer core material is placed into a composite aluminum film bag, the vacuum heat sealing machine is set to a vacuum degree of 0.1 Pa, and the pressure is maintained for 10 minutes to obtain the multi-layer glass fiber insulation board.

[0066] Comparative Example 1: Calcium stearate was used instead of the superdispersant, as detailed below, with other aspects the same as in Example 1;

[0067] S1: Preheat the nano-silica to 100-110℃ with an open flame and stir at 100-200 r / min for 10-15 min; adjust the temperature to 80-100℃, slowly add calcium stearate to the nano-silica, and stir at 400-800 r / min for 10-20 min to obtain modified silica.

[0068] Comparative Example 2: When preparing the superdispersant, only maleic anhydride and tris(2-acryloyloxyethyl) isocyanurate were used for the reaction, as detailed below, with other aspects the same as in Example 1;

[0069] S1: Preparation method of superdispersant: Add 36 parts of maleic anhydride and 51 parts of tris(2-acryloyloxyethyl)isocyanurate to 100 parts of toluene, stir to dissolve, and divide the solution into two parts, A and B. Heat solution A to 60°C, then add 0.33 parts of azobisisobutyronitrile to solution A and stir for 40 min. While maintaining the reaction temperature, add solution B dropwise to solution A at a rate of 15 drops / min. After solution B is completely added, let stand for 2 h. Finally, filter, wash and dry to obtain the superdispersant.

[0070] Comparative Example 3: Glass fiber was added to the dispersion and mixed evenly. After dehydration, it was opened, mixed with cotton, combed and laid into a web and sewn to obtain glass fiber mat. Other processes were the same as in Example 1.

[0071] Comparative Example 4: Para-aramid fibers were used instead of meta-aramid fibers, as detailed below, with other aspects the same as in Example 1;

[0072] Comparative Example 5: No heat fusion welding is performed; sewing is performed directly, as detailed below. Other aspects are the same as in Example 1.

[0073] Resin sheets and glass / aramid fiber mats are cross-layered and stacked to the required number of layers. After cutting, a multi-layer core material is obtained. Then, it is sewn, packaged, and vacuum-sealed to obtain a multi-layer glass fiber insulation board.

[0074] Comparative Example 6: Using only fiberglass mat as the core material, it was stacked to a thickness of 23mm, and after cutting and heat-fusion, a multi-layer core material was obtained; then it was sewn, and finally packaged and vacuum-sealed to obtain a multi-layer fiberglass insulation board.

[0075] Performance testing: The insulation boards obtained in Examples 1-3 and Comparative Examples 1-6 were tested, and their thermal conductivity was measured as shown in the table below:

[0076]

[0077] The test results above show that Example 1 is the best; the vacuum insulation board of the present invention has a low thermal conductivity and better insulation performance compared with fiber felt insulation boards made directly from a single material; compared with Examples 1 and 2, the isocyanuric acid group in the superdispersant prepared by the present invention can significantly reduce the thermal conductivity of the core material; compared with Comparative Example 3, the composite fiber felt has better thermal conductivity and performance; compared with Comparative Example 5, the hot-melt bonding can significantly improve the adhesion between different materials, increase the vacuum degree, and thus improve the insulation performance of the insulation board.

[0078] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for the production of a multilayer glass fiber insulation board, characterized in that: The method comprises the following steps: S1: preparing a hyperdispersant by modifying nano-silica and then melt-extruding the modified nano-silica and polyethylene terephthalate through a single-screw extruder to obtain resin sheets; S2: mixing glass fibers and aramid fibers in a dispersion liquid, opening, mixing, carding, laying and sewing to obtain a glass / aramid fiber felt; S3: cross-laminating the resin sheets and the glass / aramid fiber felt, stacking to the required number of layers, cutting and hot-welding to obtain a multilayer core material, and then sewing to obtain a multilayer glass fiber insulation board after packaging and vacuumizing; In S1, the hyperdispersant is prepared by adding N-vinylacetamide, maleic anhydride and tris(2-acryloyloxyethyl) isocyanurate into sufficient toluene, stirring to dissolve, and uniformly dividing the solution into two parts A and B; heating solution A to 50-70 DEG C, adding an appropriate amount of azobisisobutyronitrile to solution A, stirring for 30-60 min, maintaining the reaction temperature, and adding solution B to solution A at a rate of 10-30 drops / min, standing for 1-2 h, and finally filtering, washing and drying to obtain the hyperdispersant; In the hyperdispersant, the mass ratio of N-vinylacetamide, maleic anhydride and tris(2-acryloyloxyethyl) isocyanurate is 10:12:17, and the amount of azobisisobutyronitrile added is 0.5-1.2% of the mass of N-vinylacetamide; In S1, the modification process of nano-silica is as follows: preheating the nano-silica, heating to 100-110 DEG C with open heating, and stirring at a speed of 100-200 r / min for 10-15 min; adjusting the temperature to 80-100 DEG C, slowly adding the hyperdispersant to the nano-silica, and stirring at a speed of 400-800 r / min for 10-20 min to obtain modified silica; In the modification process of nano-silica, the mass ratio of nano-silica to hyperdispersant is 10:(0.5-1.2); In S2, the dispersion liquid is mixed by deionized water, hyperdispersant and thickening agent, and the mass ratio of the three is 10:(0.2-0.4):(0.4-1); the amount of the dispersion liquid added is 2.5-5% of the mass of the glass fibers and aramid fibers; and the aramid fibers are meta-aramid fibers; In S3, the hot-welding is as follows: heating the stacked resin sheets and glass / aramid fiber felt to 240-250 DEG C and applying a certain pressure to compress the stacked resin sheets and glass / aramid fiber felt to 85-87% of the original thickness to obtain a multilayer core material.

2. A process for the production of a multi-layer glass fibre insulation board according to claim 1, characterized in that: In S2, the sewing process is as follows: cross-sewing with meta-aramid sewing thread at a spacing of 6-8 cm and a line spacing; and in S3, the sewing process is as follows: sewing from one corner of the multilayer core material to an adjacent corner with meta-aramid sewing thread, and sequentially sewing and connecting the remaining adjacent corners until all four corners are connected to adjacent corners; then sewing along two diagonal lines of the multilayer core material; and finally cross-sewing at a spacing of 4-5 cm and a line spacing.

3. A process for the production of a multi-layer glass fiber insulation board according to claim 1, characterized in that: In S1, the compression ratio of the single-screw extruder is 2.5:1~3.5:1, the melt extrusion temperature is 245~265℃; the thickness of the resin sheet is 0.04~2mm; the percentage of each component of the resin sheet: polyethylene terephthalate 87~95%, modified silicon dioxide 5~13%.

4. The process of claim 1, wherein: In S2, the length of the glass fiber is 15~20mm, and the diameter is φ5~10μm; the length of the aramid fiber is 8~12mm, and the diameter is φ10~20μm; the mass ratio of the glass fiber and the aramid fiber is 6:4; the cotton mixing: tumble mixing cotton for 30~60min; the carding and laying is cross-laying, and after laying one layer of the web, water jet reinforcement with a pressure of 200~400Mpa is carried out once until the thickness of the fiber web reaches 0.04~5mm, and finally dehydration and drying at 100~110℃.

5. A multi-layer glass fiber insulation panel, characterized by: A multi-layer glass fiber thermal insulation board prepared by the method of any one of claims 1~4.

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