Ceramic plate-shaped core material, vacuum insulation panel and preparation method and application of ceramic plate-shaped core material and vacuum insulation panel

Abstract

The invention relates to the technical field of building materials, and provides a ceramic plate-shaped core material, a vacuum insulation panel and a preparation method and application of the ceramic plate-shaped core material and the vacuum insulation panel. The ceramic plate-shaped core material is formed by pressing and sintering a biscuit comprising fumed silica and a toughening material; the step of pressure sintering comprises the substeps of keeping external pressure in the sintering process to increase the apparent density of the biscuit, wherein the apparent density of the plate-shaped core material is less than or equal to 0.7 g / cm < 3 >; at least part of the surface and at least part of the interior of the plate-shaped core material are provided with hole structures during pressure sintering, and the hole structures enable the plate-shaped core material to maintain an internal negative pressure environment after vacuum packaging so as to reduce the heat conductivity coefficient of the plate-shaped core material. The effective heat conductivity coefficient of the vacuum insulation panel can reach 0.004 W / (m.K) when vacuum packaging is complete, and after vacuum packaging fails, the effective heat conductivity coefficient of the core material is still as low as 0.021 W / (m.K).

Description

Technical Field

[0001] This invention relates to the field of building technology, and in particular to a ceramic plate-shaped core material, a vacuum insulation panel, its preparation method, and its application. Background Technology

[0002] Existing vacuum insulation panels for building exterior walls are generally prepared by vacuum hot-pressing and sealing microfiber core material, getter packs, and high-barrier film. The disadvantage of this type of vacuum insulation panel is that when cutting, drilling, riveting, etc., are required on-site, the vacuum disappears, and the panel thickness rebounds by more than 50%, making it incompatible with surrounding structures. Furthermore, after the vacuum disappears, the effective thermal conductivity of the panel increases from 0.005 W / (m·K) to 0.038~0.045 W / (m·K), which is not significantly better than that of ordinary rock wool products. Existing vacuum insulation panels with gas-silica core material are also susceptible to wind erosion of the internal non-metallic powder materials after the vacuum sealing film ages or fails due to puncture, resulting in the hollowing out of the exterior wall insulation layer, large-area wall detachment, and unusable materials. Therefore, this invention is proposed. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a ceramic plate-shaped core material, a vacuum insulation panel, its preparation method, and its application. This vacuum insulation panel can be cut, drilled, and riveted on-site at construction sites. When the vacuum sealing is effective, its apparent thermal conductivity is 0.004 W / (m·K). Even after cutting or drilling causes the vacuum sealing to fail, its apparent thermal conductivity remains as low as 0.021 W / (m·K), which is significantly better than existing technologies.

[0004] In a first aspect, the present invention provides a plate-shaped core material of ceramic material, which is formed by pressure sintering of a green body comprising fumed silica and a toughening material; the pressure sintering includes maintaining external pressure during the sintering process to increase the apparent density of the green body, wherein the apparent density of the plate-shaped core material is less than or equal to 0.7 g / cm³. 3 ; During the pressure sintering process, at least a portion of the surface and at least a portion of the interior of the plate-shaped core material are provided with a porous structure. The porous structure enables the plate-shaped core material to maintain an internal negative pressure environment after vacuum sealing to reduce its thermal conductivity. The toughening material is selected from one or more of quartz fiber, glass fiber, and ZnO whiskers.

[0005] According to the ceramic plate-shaped core material provided by the present invention, the pressure sintering increases the apparent density of the green body by less than or equal to 50%.

[0006] According to the plate-shaped core material of ceramic material provided by the present invention, the mass ratio of fumed silica in the green body is greater than or equal to 40%; preferably greater than or equal to 60%, preferably greater than or equal to 70%, preferably greater than or equal to 70%, preferably greater than or equal to 80%, preferably greater than or equal to 85%.

[0007] And / or, the mass percentage of toughening material in the green blank is less than or equal to 10%, preferably 5-10%.

[0008] According to the ceramic plate-shaped core material provided by the present invention, the green body further includes fly ash, and the mass ratio of the fly ash to the fumed silica is less than or equal to 1.

[0009] According to the ceramic plate-shaped core material provided by the present invention, the green body further includes a light-blocking agent; Preferably, the mass percentage of the opaque agent in the raw blank is less than or equal to 25%, and more preferably 5-25%.

[0010] According to the ceramic plate-shaped core material provided by the present invention, the water contact angle of the plate-shaped core material is greater than or equal to 150°.

[0011] According to the ceramic plate core material provided by the present invention, the pressure sintering includes maintaining an external force of greater than or equal to 30 kPa during the sintering process at a temperature of 800~1250℃ to increase the apparent density of the green body. Preferably, the temperature is 800~1100℃.

[0012] Secondly, the present invention provides a method for preparing a plate-shaped core material of ceramic material as described above, comprising: forming a green body comprising fumed silica and a toughening material by pressure sintering; wherein the pressure sintering includes maintaining external pressure during the sintering process to increase the apparent density of the green body, and the apparent density of the plate-shaped core material is less than or equal to 0.7 g / cm³. 3 ; The pressure sintering process simultaneously enables at least a portion of the surface and at least a portion of the interior of the plate-shaped core material to have a porous structure.

[0013] Thirdly, the present invention provides a vacuum insulation panel, comprising a plate-shaped core material of ceramic material as described above, or a plate-shaped core material of ceramic material prepared by the preparation method described above.

[0014] Fourthly, the present invention provides the application of the vacuum insulation panels described above in zero-carbon buildings, passive houses, cold chain logistics of fruits and vegetables, cold chain logistics vehicle panels, cold storage wall panels, and ultra-thin energy-saving refrigerator insulation layers.

[0015] This invention provides a ceramic plate-shaped core material, a vacuum insulation board, its preparation method, and its application. The process involves using fumed silica and toughening materials, pressing to obtain a green blank, followed by pressure sintering to obtain a strong and lightweight ceramic plate-shaped core material, which is then vacuum-sealed to obtain a vacuum insulation board. The vacuum insulation board of this invention achieves an effective thermal conductivity of 0.004 W / (m·K) when the vacuum sealing is intact, meeting the performance level of Type II vacuum insulation boards specified in GB / T 37608-2019 "Vacuum Insulation Boards". Even after vacuum sealing failure, the effective thermal conductivity of the core material remains as low as 0.021 W / (m·K), meeting the performance level of Class A aerogels specified in GB / T34336-2017 "Nanoporous Aerogel Composite Insulation Products". Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is the Tg-DTA curve of fly ash provided by the present invention.

[0018] Figure 2 This is a SEM image of fly ash provided by the present invention.

[0019] Figure 3 This is a magnified SEM image of fly ash provided by the present invention.

[0020] Figures 4-5 These are cross-sectional SEM images of the ceramic plate-shaped core material prepared according to Example 1A of the present invention at different magnifications.

[0021] Figure 6 This is a surface SEM image of the ceramic plate-shaped core material obtained in Example 1A of the present invention.

[0022] Figure 7 This is a cross-sectional SEM image of the ceramic plate-shaped core material obtained in Example 2A of the present invention.

[0023] Figure 8 This is a surface SEM image of the ceramic plate-shaped core material obtained in Example 2A of the present invention.

[0024] Figure 9 This is a cross-sectional SEM image of the ceramic plate-shaped core material obtained in Example 3A of the present invention.

[0025] Figure 10This is a surface SEM image of the ceramic plate-shaped core material obtained in Example 4A of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] The following is combined with Figures 1-10 The present invention describes a plate-shaped core material made of ceramic material, a vacuum insulation panel, its preparation method, and its application.

[0028] In a specific embodiment of the present invention, a plate-shaped core material of ceramic material is first provided, which is formed by pressure sintering of a green body comprising fumed silica and a toughening material; the pressure sintering includes maintaining external pressure during the sintering process to increase the apparent density of the green body, and the apparent density of the plate-shaped core material is less than or equal to 0.7 g / cm³. 3 ; During the pressure sintering process, at least a portion of the surface and at least a portion of the interior of the plate-shaped core material are provided with a porous structure. The porous structure enables the plate-shaped core material to maintain an internal negative pressure environment after vacuum sealing to reduce its thermal conductivity. The toughening material is selected from one or more of quartz fiber, glass fiber, and ZnO whiskers.

[0029] The apparent density of the plate-shaped core material described in this invention is less than or equal to 0.7 g / cm³. 3 For example, it can be 0.1 g / cm³ 3 0.2g / cm 3 0.3 g / cm 3 0.4 g / cm 3 0.5 g / cm 3 0.6 g / cm 3 0.7 cm 3 Any value or a range of data consisting of any values ​​in the range.

[0030] Preferably, the pore structure is a nanoporous structure.

[0031] Preferably, the average diameter of the quartz fiber is 1~3μm.

[0032] Preferably, the glass fiber is a high-silica glass fiber; more preferably, the average diameter of the glass fiber is 7~10μm.

[0033] Preferably, the average diameter of the ZnO whiskers is 200-300 nanometers.

[0034] In some specific embodiments, the pressure sintering increases the apparent density of the green blank by less than or equal to 50%, for example, it can be any value or a range of any values ​​among 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%.

[0035] In some specific embodiments, the mass percentage of fumed silica in the green blank is greater than or equal to 40%; preferably greater than or equal to 60%, preferably greater than or equal to 70%, preferably greater than or equal to 70%, preferably greater than or equal to 80%, and preferably greater than or equal to 85%.

[0036] In some specific embodiments, the mass percentage of toughening material in the green blank is less than or equal to 10%, for example, it can be any value or a range of any values ​​from 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, preferably 5~10%.

[0037] In some specific embodiments, the green blank further includes fly ash, and the mass ratio of the fly ash to the fumed silica is less than or equal to 1. For example, it can be any value or a range of any values ​​from 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0.

[0038] Research has found that this invention uses low-cost fly ash as a raw material to replace a portion of fumed silica, achieving a core material with excellent mechanical and thermal insulation properties, without shedding powder and at a low cost.

[0039] In some specific embodiments, the green blank also includes a light-blocking agent.

[0040] In some specific embodiments, the mass percentage of the opaque agent in the green blank is less than or equal to 25%, for example, it can be any value or a range of any values ​​among 5%, 10%, 15%, 20%, and 25%, preferably 5~25%.

[0041] In some specific embodiments, the light-blocking agent is selected from one or more of silicon carbide powder, silicon powder, titanium dioxide, carbon black, and Si-OC mesoporous microspheres (CN 202510794365.4).

[0042] To reduce costs, the silicon powder can be obtained by crushing recycled solar silicon panels to obtain silicon powder with an average particle size of 3~5μm.

[0043] For building insulation materials, according to Wien's displacement law λ=b / T (b=0.002897m·K); in summer, the outdoor temperature is as high as about 40℃, and the infrared radiation energy of the heat source at 40℃ is mainly concentrated at a wavelength of 9.25μm; in winter, the indoor temperature is about 25℃, and the infrared radiation energy of the indoor heat source radiating heat to the outdoor space is mainly concentrated at a wavelength of 9.72μm. Therefore, the preferred particle size D of silicon carbide in this invention is... 50 It is 10~12μm.

[0044] In some specific embodiments, the preform is obtained by pressing a mixture of fumed silica, a light-blocking agent, and a toughening material.

[0045] In some specific embodiments, the water contact angle of the plate-shaped core material is greater than or equal to 150°, for example, it can be any value or a range of values ​​among 150°, 155°, 160°, 165°, 170°, 175°, and 180°. In the prior art, if the core material of a vacuum insulation panel is hydrophilic, its volume expansion rate is high after absorbing water in humid or rainy weather, making it prone to delamination. The present invention uses a gas-phase CVD hydrophobic process to give the plate-shaped core material intrinsic hydrophobicity, thereby giving it excellent weather resistance when used as a building exterior wall insulation material, and the hydrophobic properties can be maintained for 50 years.

[0046] In some specific embodiments, the pressure sintering includes applying an external force of greater than or equal to 30 kPa during the sintering process at a temperature of 800~1250°C to increase the apparent density of the green blank.

[0047] In some specific embodiments, the temperature is 800~1100℃, for example, it can be any value or a data range composed of any values ​​among 800℃, 830℃, 860℃, 890℃, 920℃, 950℃, 980℃, 1010℃, 1040℃, 1070℃, and 1100℃.

[0048] In some specific embodiments, when the toughening material is selected from high silica glass fiber, the temperature is 800~950℃, for example, it can be any value or a range of values ​​among 800℃, 830℃, 860℃, 890℃, 920℃, and 950℃.

[0049] In a specific embodiment of the present invention, a method for preparing a plate-shaped core material of ceramic material as described above is also provided, comprising: forming a green body comprising fumed silica and a toughening material by pressure sintering; wherein the pressure sintering includes maintaining external pressure during the sintering process to increase the apparent density of the green body, and the apparent density of the plate-shaped core material is less than or equal to 0.7 g / cm³. 3 ; The pressure sintering process simultaneously enables at least a portion of the surface and at least a portion of the interior of the plate-shaped core material to have a porous structure.

[0050] In some specific embodiments, the method for preparing the plate-shaped core material of the ceramic material includes: A mixture of fumed SiO2, a light-blocking agent, and a toughening material yields a bulk density of 40-60 kg / m³. 3 The composition.

[0051] The composition is transferred to a pressing mold, the upper surface is smoothed, and the mold is closed and pressed. The thickness of the pressed green body is controlled by positioning pins. After pressing, an apparent density of 0.15~0.50 g / cm³ is obtained. 3 The unfinished blank.

[0052] The green blank is transferred to a silicon carbide sintering plate, and silicon carbide positioning posts are placed on the four sides of the green blank. Another silicon carbide heat spreader is then pressed onto the upper surface of the green blank. The silicon carbide heat spreader applies pressure to the green blank to the target pressure before sintering and maintains this pressure during the sintering process. The sintering procedure is as follows: the temperature is increased from room temperature to 800-1250℃ at a rate of 0.5-5℃ / min, held at this temperature for 0.5-2 hours, and then naturally cooled to room temperature, resulting in a ceramic plate-shaped core material. At least a portion of the surface and at least a portion of the interior of this plate-shaped core material possesses a nanoporous structure. This nanoporous structure allows the plate-shaped core material to maintain an internal negative pressure environment after vacuum sealing, thereby reducing its thermal conductivity.

[0053] Preferably, the target pressure is greater than or equal to 30 kPa.

[0054] The apparent density described in this invention is 0.15~0.50 g / cm³. 3 The raw blank, for example, can be 0.15 g / cm³. 3 0.20 g / cm 3 0.25 g / cm 3 0.30 g / cm 3 0.35 g / cm 3 0.40 g / cm 3 0.45 g / cm 3 0.50 g / cm 3 Any value or a range of data consisting of any values ​​in the range.

[0055] The heat preservation time of 0.5~2h mentioned in this invention can be any value or a range of values ​​among 0.5h, 1.0h, 1.5h, and 2.0h.

[0056] In a specific embodiment of the present invention, a vacuum insulation panel is also provided, comprising a plate-shaped core material of ceramic material as described above, or a plate-shaped core material of ceramic material prepared by the preparation method described above.

[0057] In some specific embodiments, the apparent thermal conductivity of the ceramic plate-shaped core material is 0.018~0.035 W / (m·K). For example, it can be any value or a range of values ​​from 0.018 W / (m·K), 0.020 W / (m·K), 0.022 W / (m·K), 0.024 W / (m·K), 0.026 W / (m·K), 0.028 W / (m·K), 0.030 W / (m·K), 0.032 W / (m·K), 0.034 W / (m·K), and 0.035 W / (m·K).

[0058] In some specific embodiments, the compressive strength of the ceramic plate core material at 5% compression is 0.40~0.65 MPa. For example, it can be any value or a range of values ​​among 0.40 MPa, 0.45 MPa, 0.50 MPa, 0.55 MPa, 0.60 MPa, and 0.65 MPa.

[0059] In some specific embodiments, the compressive strength of the ceramic plate-shaped core material at 8% compression is 0.50~1.15 MPa. For example, it can be any value or a range of values ​​from 0.50 MPa, 0.55 MPa, 0.60 MPa, 0.65 MPa, 0.70 MPa, 0.75 MPa, 0.80 MPa, 0.85 MPa, 0.90 MPa, 0.95 MPa, 1.00 MPa, 1.05 MPa, 1.10 MPa, and 1.15 MPa.

[0060] In some specific embodiments, the flexural strength of the ceramic plate-shaped core material is 0.25~0.53 MPa. For example, it can be any value or a range of values ​​from 0.25 MPa, 0.30 MPa, 0.35 MPa, 0.40 MPa, 0.45 MPa, 0.50 MPa, and 0.53 MPa.

[0061] In specific embodiments of the present invention, the application of the vacuum insulation panels described above in zero-carbon buildings, passive houses, fresh fruit and vegetable logistics, cold chain logistics vehicle panels, cold storage wall panels, and ultra-thin energy-saving refrigerator insulation layers is also provided.

[0062] In some specific embodiments, the apparent thermal conductivity of the vacuum insulation panel is no higher than 0.005 W / (m·K).

[0063] The following are the model or parameter information of some of the raw materials used in the embodiments of the present invention: Vaporized SiO2: Shandong Dongyue Chemical A200 type.

[0064] Hydrophilic fumed silica: N20 type hydrophilic fumed silica (specific surface area 200m²) produced by Evonik Specialty Chemicals (Shanghai) Co., Ltd. 2 / g, particle size 10~20nm).

[0065] Silicon carbide powder: Beijing Micro-Nano Ultrafine Materials Co., Ltd., 1200~1500 mesh.

[0066] Short-cut quartz fibers: Hubei Feilihua Quartz Glass Co., Ltd., Type A, with a diameter distribution of 1~3μm. Loose fibers are cut into 10mm×10mm fragments, and then pulped in a pulper with water added at a mass ratio of 1:199. Ammonia is added during the pulping process to make the pH value of the quartz fiber pulp ≥10. Finally, the quartz fibers are taken out of the pulp and dried in an oven at 120℃ for later use.

[0067] Fly ash: provided by Hubei Xingfa Group, its Tg-DTA curve and SEM are as follows. Figures 1-3 As shown in the figure. From the Tg-DTA curve of fly ash, it can be seen that fly ash contains approximately 3% moisture, and pretreatment at temperatures above 200℃ can completely remove the adsorbed moisture. From the SEM image of fly ash (… Figures 2-3 As can be seen, it exhibits a loose and porous structure, containing a small number of closed-cell microspheres. Detailed images of the localized loose and porous structure of fly ash are shown below. Figure 3 As shown.

[0068] ZnO whiskers: Provided by the Department of Chemical Engineering, Tsinghua University. The preparation method is referenced in: Lin, S., et al. (2025). "SDBS / SDSN-assisted alkaline dissolution-conversion of ε-Zn(OH)2 strategy for efficient synthesis of 1D ZnO with enhanced mechanicalproperty." Applied Surface Science 690.

[0069] High silica glass fiber wool: provided by Nanjing Glass Fiber Research and Design Institute Co., Ltd., with a maximum continuous operating temperature of less than or equal to 1100℃ and a fiber diameter of 7~10μm.

[0070] Ultra-fine glass fiber cotton: purchased from Chongqing Zaisheng Technology Co., Ltd., with a maximum continuous operating temperature of 450℃.

[0071] The model or parameter information of some of the devices used in the embodiments of this invention is as follows: Mechanical fusion machine: Mechano Fusion® model manufactured by Hosokawa Micron Co., Ltd., Japan.

[0072] When testing the plate-shaped core material of ceramic material of the present invention, the testing method involves: Test method for apparent thermal conductivity: GB / T 10295-2008 Determination of steady-state thermal resistance and related properties of thermal insulation materials by heat flux meter method.

[0073] Test method for compressive strength: GB / T 5486-2008 Test methods for inorganic rigid thermal insulation products.

[0074] Test method for flexural strength: GB / T 5486-2008 Test methods for inorganic rigid thermal insulation products.

[0075] Thermal insulation performance: 100mm×100mm×h (thickness / mm) samples with different numbers were placed on the heating table. The front of the heating table was kept at 600℃. After 20 minutes, the temperature of the back of the sample was recorded (hereinafter, the back temperature (℃) is used to represent the temperature of the back of the sample).

[0076] Example 1A: Plate-shaped core material made of ceramic material This embodiment provides a plate-shaped core material made of ceramic, and its preparation method is as follows: S1: Place 80 parts by weight of fumed SiO2, 15 parts by weight of silicon carbide powder, and 5 parts by weight of chopped quartz fiber into a mechanical fusion machine and stir at 800 rpm for 5 minutes to obtain a loose bulk density of 40~60 kg / m³. 3 Composition A.

[0077] S2: Transfer composition A into a pressing mold, smooth the upper surface, close the mold, and press. Control the thickness of the pressed green body using positioning pins. After pressing, obtain a green body measuring 300mm × 300mm × 10.80mm with an apparent density of 0.30g / cm³. 3 The raw blank B.

[0078] S3: Transfer the green blank B to the silicon carbide sintering plate. Place 9mm thick silicon carbide positioning posts on the four sides of the green blank B. Press another silicon carbide heat spreader plate on the upper surface of the green blank B. Refer to the appendix of CN 201510632711.5 for the sintering plate position. Figure 2 The silicon carbide heat spreader applies a pressure of 50 kPa to the green blank (B) before sintering and maintains this pressure during sintering. The sintering procedure is as follows: the temperature is increased from room temperature to 950℃ at a rate of 2℃ / min, held for 1 hour, and then naturally cooled to room temperature to obtain the ceramic plate-shaped core material. Figures 4-6It can be seen that at least part of the surface and at least part of the interior of the plate-shaped core material have nanoporous structures. The nanoporous structures enable the plate-shaped core material to maintain an internal negative pressure environment after vacuum sealing, thereby reducing its thermal conductivity.

[0079] The ceramic plate-shaped core material has a thickness of 10.00 mm and an apparent density of 0.32 g / cm³. 3 The apparent thermal conductivity is 0.021 W / (m·K), the compressive strength (5% compression) is 0.52 MPa, the compressive strength (8% compression) is 1.0 MPa, and the flexural strength is 0.45 MPa.

[0080] Examples 2A-5A: Plate-shaped core material made of ceramic material This embodiment provides a plate-shaped core material made of ceramic, and its preparation method is basically the same as that of Example 1A, except that the sintering temperature during the holding period in the sintering process is different, as shown in the table below: Table 1

[0081] Correspondingly, the structural and performance parameters of the ceramic plate-shaped core materials obtained in each embodiment are as follows: Example 2A: Thickness 9.80 mm, apparent density 0.33 g / cm³ 3 The apparent thermal conductivity is 0.022 W / (m·K), the compressive strength (5% compression) is 0.55 MPa, the compressive strength (8% compression) is 1.02 MPa, and the flexural strength is 0.47 MPa. At least a portion of the surface and at least a portion of the interior of this plate-like core material possesses a nanoporous structure, as shown in the partial structural schematic diagram below. Figures 7-8 As shown.

[0082] Example 3A: Thickness 9.50 mm, apparent density 0.34 g / cm³ 3 The apparent thermal conductivity is 0.023 W / (m·K), the compressive strength (5% compression) is 0.57 MPa, the compressive strength (8% compression) is 1.03 MPa, and the flexural strength is 0.48 MPa. At least a portion of the surface and at least a portion of the interior of this plate-like core material possess a nanoporous structure, as shown in the partial structural schematic diagram below. Figure 9 As shown.

[0083] Example 4A: Thickness is 9.20 mm, with a 10% shrinkage in both length and width directions, and an apparent density of 0.43 g / cm³. 3The apparent thermal conductivity is 0.030 W / (m·K), the compressive strength (5% compression) is 0.65 MPa, the compressive strength (8% compression) is 1.13 MPa, and the flexural strength is 0.52 MPa. At least a portion of the surface and at least a portion of the interior of this plate-like core material possess a nanoporous structure, as shown in the partial structural schematic diagram below. Figure 10 As shown.

[0084] Example 5A: The sample had a thickness of 8.20 mm, with a 10% shrinkage in both length and width directions. It was no longer a uniform block shape and had a warped surface. After machining to a flat size of 300 mm × 300 mm × 7.5 mm, the apparent density was measured to be 0.65 g / cm³. 3 The apparent thermal conductivity is 0.035 W / (m·K), the compressive strength (5% compression) is 0.60 MPa, the compressive strength (8% compression) is 0.90 MPa, and the flexural strength is 0.30 MPa.

[0085] Based on the above data, it can be seen that as the sintering temperature increases, the apparent density of the sintered green body gradually increases, and the mechanical properties of the ceramic plate-shaped core material also gradually improve. Due to the increase in apparent density, the solid-state thermal conductivity of the ceramic plate-shaped core material increases significantly. However, when the sintering temperature is raised above 1200℃, the volume shrinkage during the sintering process is severe, the surface of the fired product is no longer smooth, and the excessively high sintering temperature leads to abnormal grain growth in the core material, increasing intergranular porosity and defects. Although the apparent density of the plate increases, the mechanical strength decreases. Therefore, it is recommended to control the sintering temperature between 950~1100℃.

[0086] Furthermore, the experiment revealed that to improve sintering efficiency and reduce sintering time, a sintering procedure of 1100℃ and holding time ≤30min can be used for thin plates (thickness ≤5mm), while a sintering procedure of 950℃ and holding time ≥1h should be used for thick plates (thickness ≥10mm). For thick plates, excessively short holding times can easily lead to the formation of a hard ceramic shell in the ceramic plate-shaped core material, while the internal inorganic powder is not fully sintered.

[0087] Example 6A: Plate-shaped core material made of ceramic material This embodiment provides a plate-shaped core material made of ceramic material, the preparation method of which is basically the same as that of Example 1A, except that the amount of composition A is adjusted to 336.60g. During pressing, the thickness of the green body is controlled by the height of the positioning column, resulting in a green body B with dimensions of 300mm × 300mm × 22.0mm and an apparent density of 0.17g / cm³. 3 The height of the silicon carbide pad during sintering is 19.5 mm, and the pressure applied to the green blank by the silicon carbide heat spreader covering the upper surface during sintering is the same as in Example 1A.

[0088] The resulting ceramic plate-shaped core material has a mass of 332.80 g, dimensions of 300 mm × 300 mm × 18.49 mm, and an apparent density of 0.20 g / cm³. 3 The apparent thermal conductivity is 0.018 W / (m·K), the compressive strength is 0.40 MPa (5% compression) and 0.50 MPa (8% compression); the flexural strength is 0.25 MPa.

[0089] Example 7A: Plate-shaped core material made of ceramic material This embodiment provides a plate-shaped core material made of ceramic material, the preparation method of which is basically the same as that of Example 1A, except that the amount of composition A is adjusted to 434.7g. During pressing, the thickness of the green body is controlled by the height of the positioning pins. The green body dimensions are 300mm × 300mm × 21.0mm, and the apparent density of the green body is 0.23g / cm³. 3 The height of the silicon carbide pad during sintering is 19.5 mm, and the pressure applied to the green blank by the silicon carbide heat spreader covering the upper surface during sintering is the same as in Example 1A.

[0090] The resulting ceramic plate-shaped core material has a mass of 429.80 g, dimensions of 300 mm × 300 mm × 19.10 mm, and an apparent density of 0.25 g / cm³. 3 The apparent thermal conductivity is 0.020 W / (m·K), the compressive strength is 0.40 MPa (5% compression) and 0.50 MPa (8% compression); the flexural strength is 0.35 MPa.

[0091] Example 8A: Plate-shaped core material made of ceramic material This embodiment provides a plate-shaped core material made of ceramic material, the preparation method of which is basically the same as that of Example 1A, except that the amount of composition A is adjusted to 638.55g. During pressing, the thickness of the green body is controlled by the height of the positioning column. The green body dimensions are 300mm × 300mm × 21.5mm, and the apparent density of the green body is 0.33g / cm³. 3 The height of the silicon carbide pad during sintering is 19.5 mm, and the pressure applied to the green blank by the silicon carbide heat spreader covering the upper surface during sintering is the same as in Example 1A.

[0092] The resulting ceramic plate-shaped core material weighs 632.79 g, has dimensions of 300 mm × 300 mm × 20.09 mm, and an apparent density of 0.35 g / cm³. 3 The apparent thermal conductivity is 0.022 W / (m·K), the compressive strength is 0.60 MPa (5% compression) and 1.15 MPa (8% compression); the flexural strength is 0.53 MPa.

[0093] Example 9A: Plate-shaped core material made of ceramic This embodiment provides a plate-shaped core material made of ceramic material, the preparation method of which is basically the same as that of Example 1A, except that the amount of composition A is adjusted to 1067.04g. During pressing, the thickness of the green body is controlled by the height of the positioning pins. The green body dimensions are 300mm × 300mm × 20.80mm, and the apparent density of the green body is 0.57g / cm³. 3 The height of the silicon carbide pad during sintering is 19.5 mm, and the pressure exerted on the green blank by the silicon carbide heat spreader covering the upper surface during sintering is the same as in Example 1A.

[0094] The resulting ceramic plate-shaped core material has a mass of 1048.70 g, dimensions of 300 mm × 300 mm × 20.09 mm, and an apparent density of 0.58 g / cm³. 3 The apparent thermal conductivity is 0.025 W / (m·K), the compressive strength is 0.60 MPa (5% compression) and 1.15 MPa (8% compression); the flexural strength is 0.53 MPa.

[0095] As can be seen from the test results of Examples 6A to 9A above, the lower the density of the core material, the lower the raw material cost and the lower the solid thermal conductivity. However, the mechanical properties will also be reduced. Therefore, a suitable apparent density of the green blank can be selected to prepare a plate-shaped core material of ceramic material that achieves a balance between mechanical properties, thermal insulation properties and manufacturing cost.

[0096] Examples 10A~17A: Plate-shaped core material made of ceramic material Examples 10A-17A provide a plate-shaped core material made of ceramic material, the preparation method of which is basically the same as that of Example 1A, the only difference being: By adjusting the apparent density of the green body and the sintering process, plate-shaped core materials of ceramic materials with different apparent densities were prepared. The sample size was 100mm×100mm×(10~12)mm.

[0097] The apparent density and corresponding thermal insulation performance of the ceramic plate core materials of Test Examples 10A~17A are shown in the table below: Table 2

[0098] As can be seen from the table above, the apparent density should be 0.32 g / cm³. 3 The ceramic plate core material can balance low solid-phase heat conduction and low radiative heat transfer, achieving the best overall thermal insulation performance.

[0099] Examples 18A~22A: Plate-shaped core material made of ceramic material Examples 18A-22A provide a plate-shaped core material made of ceramic material, the preparation method of which is basically the same as that of Example 1A, except that the formulation of composition A is adjusted, as shown in the table below. Simultaneously, by adjusting the apparent density of the green body and the sintering procedure, an apparent density of 0.33 g / cm³ is prepared. 3 The ceramic plate-shaped core material samples were all 100mm×100mm×10mm in size.

[0100] The test results of the thermal insulation performance of the ceramic plate core materials of Examples 18A to 22A are shown in the table below.

[0101] Table 3

[0102] The test results show that the best heat insulation effect can be obtained when the amount of silicon carbide powder is 15wt% of the total mass of composition A.

[0103] Examples 23A-24A: Plate-shaped core material made of ceramic material Examples 23A-24A provide a plate-shaped core material made of ceramic material, the preparation method of which is basically the same as that of Example 1A, except that the formulation of composition A is adjusted, as shown in the table below. Simultaneously, by adjusting the apparent density of the green body, the apparent density of the prepared material is 0.33 g / cm³. 3 The ceramic plate-shaped core material samples were all 100mm×100mm×10mm in size.

[0104] The test results of the thermal insulation performance of the ceramic plate core materials of Examples 23A~24A are shown in the table below.

[0105] Table 4

[0106] As can be seen from the table above, using different amounts of low-cost fly ash to replace high-priced fumed silica will have a certain impact on the mechanical and thermal insulation properties of the finished product. However, when the amount of fly ash is low, such as controlling its mass ratio with fumed SiO2 to be less than or equal to 1, the cost can be significantly reduced, but the thermal insulation and mechanical properties can still meet the application requirements of vacuum insulation panels.

[0107] Examples 25A-26A: Plate-shaped core material made of ceramic material Examples 25A-26A provide a ceramic plate-shaped core material, the preparation method of which is basically the same as that of Example 1A, except that the formulation of composition A is adjusted, as shown in the table below. Simultaneously, by adjusting the apparent density of the green body and the sintering procedure, an apparent density of 0.33 g / cm³ is prepared. 3The ceramic plate-shaped core material samples were all 100mm×100mm×10mm in size.

[0108] The test results of the thermal insulation and mechanical properties of the ceramic plate core materials of Examples 25A~26A are shown in the table below.

[0109] Table 5

[0110] The data above shows that using ZnO whiskers to replace quartz fibers has no significant impact on the shrinkage rate of the green blank during sintering, the thermal insulation performance of the product, or the mechanical properties of the product.

[0111] Example 27A: Plate-shaped core material made of ceramic material This embodiment provides a plate-shaped core material made of ceramic material, which is prepared in a manner that is basically the same as that in Embodiment 1A, except that the short-cut quartz fibers are replaced with high-silica glass fiber cotton.

[0112] Example 28A: Plate-shaped core material made of ceramic material This embodiment provides a plate-shaped core material made of ceramic material, which is prepared in a manner that is basically the same as that in Embodiment 2A, except that the short-cut quartz fibers are replaced with high-silica glass fiber cotton.

[0113] Based on the analysis of the results of Examples 27A and 28A, at sintering temperatures of 950°C or less, there is no significant difference in shrinkage rate between green bodies prepared using high-silica glass fibers and those prepared using quartz fibers during the sintering process. However, when the sintering temperature is greater than or equal to 1000°C, the green bodies prepared using high-silica glass fibers experience severe shrinkage during the sintering process.

[0114] Example 29A: Plate-shaped core material made of ceramic This embodiment provides a plate-shaped core material made of ceramic material, the preparation method of which is basically the same as that of Example 1A, except that the same mass of fumed SiO2 is replaced with hydrophilic fumed silica. The results show that the two have basically the same thermal insulation performance and mechanical properties for the plate-shaped core material made of ceramic material.

[0115] Example 30A: Plate-shaped core material made of ceramic material This embodiment provides a plate-shaped core material made of ceramic, the preparation method of which is basically the same as that of Example 1A, except that: The ceramic plate-shaped core material obtained in Example 1A was further subjected to hydrophobic treatment. The hydrophobic treatment steps were as follows: the ceramic plate-shaped core material obtained in Example 1A was placed in a vacuum vapor-phase hydrophobic tank, hexamethyldisilazane vapor with a partial pressure of 10 kPa was introduced into the tank, and after sealing at 120°C for 30 minutes, it was taken out to obtain an intrinsically hydrophobic ceramic plate-shaped core material.

[0116] The intrinsically hydrophobic ceramic plate core material exhibits a weight gain of only 0.5% compared to the ceramic plate core material prepared in Example 1A, with a contact angle ≥150°C and a weight gain of ≤0.1% after immersion in water for 24 hours. Therefore, this intrinsically hydrophobic ceramic plate core material can still resist moisture and rainy weather for a long time after the outer surface vacuum seal fails.

[0117] Meanwhile, the thermal insulation and mechanical properties of the intrinsically hydrophobic ceramic plate core material were tested. The results were as follows: according to GB / T 10295-2008 Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials using a heat flow meter, its apparent thermal conductivity was 0.021 W / (m·K), compressive strength was 0.52 MPa (5% compression) and 1.0 MPa (8% compression), and flexural strength was 0.45 MPa. It can be seen that the thermal insulation and mechanical properties of this intrinsically hydrophobic ceramic plate core material did not decrease.

[0118] Comparative Example 3A: Plate-shaped core material made of ceramic material This embodiment provides a plate-shaped core material made of ceramic material, which is prepared in a manner that is basically the same as that in Example 1A, except that the short-cut quartz fibers are replaced with ultrafine glass fiber cotton.

[0119] The results show that the ultrafine glass fiber cotton has low temperature resistance and will produce large dimensional shrinkage even at a sintering temperature of 800℃.

[0120] Furthermore, the present invention uses the ceramic plate-shaped core material obtained in Examples 1A to 31A above to process and prepare a vacuum insulation panel. The following description uses some of these examples to illustrate the processing procedure. Specifically: Example 1B Vacuum Insulation Panel This embodiment provides a method for preparing a vacuum insulation panel, the steps of which are as follows: First, a vacuum insulation board core material is prepared, which is basically the same as in Example 31A, except that when pressing the blank B, a pit that can accommodate a getter pack is pressed into a predetermined position on the upper surface of the blank B. After sintering, a plate-shaped core material of ceramic material containing the pit is obtained, which is the vacuum insulation board core material.

[0121] Re-encapsulation: Place a getter pack in the recessed part of the vacuum insulation board core material, and finally place it in an STP-specific anti-expansion bag for vacuum heat sealing to obtain the vacuum insulation board.

[0122] This vacuum insulation panel can be cut, drilled, and anchored on-site. When the vacuum is maintained, its apparent thermal conductivity is 0.004 W / (m·K), and even when the vacuum fails, its apparent thermal conductivity remains at a low level of 0.021 W / (m·K). After vacuum failure, the core material retains its intrinsic waterproof properties, preventing dampness from forming in rainy or humid weather.

[0123] The test results also found that JGJ / T 416-2017 "Technical Specification for Application of Vacuum Insulation Boards for Buildings" stipulates that the thickness expansion rate of vacuum insulation boards after vacuum sealing and puncture should be ≤10%, while the thickness expansion rate of this vacuum insulation board is ≤1%. Therefore, after long-term use as an exterior wall insulation board, it is not easy for defects such as hollow insulation boards and large-area wall panel detachment to occur after the vacuum sealing fails due to aging.

[0124] According to GB 8624-2012 "Classification of Combustion Performance of Building Materials and Products", the combustion performance of this vacuum insulation panel reaches Class A.

[0125] In summary, the vacuum insulation panel of the present invention can be applied to building energy conservation fields such as zero-carbon buildings and passive houses; it can also be applied to fields such as fresh fruit and vegetable logistics, cold chain logistics vehicle panels, cold storage wall panels, and ultra-thin energy-saving refrigerator insulation layers.

[0126] 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 them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A plate-shaped core material made of ceramic, characterized in that, It is formed by pressure sintering of a green blank comprising fumed silica and toughening material; the pressure sintering includes maintaining external pressure during the sintering process to increase the apparent density of the green blank, and the apparent density of the plate-shaped core material is less than or equal to 0.7 g / cm³. 3 ; During the pressure sintering process, at least a portion of the surface and at least a portion of the interior of the plate-shaped core material are provided with a porous structure. The porous structure enables the plate-shaped core material to maintain an internal negative pressure environment after vacuum sealing to reduce its thermal conductivity. The toughening material is selected from one or more of quartz fiber, glass fiber, and ZnO whiskers.

2. The plate-shaped core material of ceramic material according to claim 1, characterized in that, The pressure sintering increases the apparent density of the green blank by less than or equal to 50%.

3. The plate-shaped core material of ceramic material according to claim 1 or 2, characterized in that, The raw preform contains 40% or more fumed silica by mass; preferably 60%, preferably 70%, preferably 70%, preferably 80%, preferably 85%; And / or, the mass percentage of toughening material in the green blank is less than or equal to 10%, preferably 5-10%.

4. The plate-shaped core material of ceramic material according to any one of claims 1 to 3, characterized in that, The green blank also includes fly ash, and the mass ratio of the fly ash to the fumed silica is less than or equal to 1.

5. The plate-shaped core material of ceramic material according to any one of claims 1 to 4, characterized in that, The green blank also includes a light-blocking agent; preferably, the mass percentage of the light-blocking agent in the green blank is less than or equal to 25%, and more preferably 5-25%.

6. The plate-shaped core material of ceramic material according to any one of claims 1 to 5, characterized in that, The water contact angle of the plate-shaped core material is greater than or equal to 150°.

7. The plate-shaped core material of ceramic material according to any one of claims 1 to 6, characterized in that, The pressure sintering includes applying an external force of greater than or equal to 30 kPa during the sintering process at a temperature of 800~1250℃ to increase the apparent density of the green blank; preferably, the temperature is 800~1100℃.

8. A method for preparing the plate-shaped core material of ceramic material according to any one of claims 1 to 7, characterized in that, include: It is formed by pressure sintering of a green blank comprising fumed silica and toughening material; the pressure sintering includes maintaining external pressure during the sintering process to increase the apparent density of the green blank, and the apparent density of the plate-shaped core material is less than or equal to 0.7 g / cm³. 3 ; The pressure sintering process simultaneously enables at least a portion of the surface and at least a portion of the interior of the plate-shaped core material to have a porous structure.

9. A vacuum insulation panel, characterized in that, Includes the plate-shaped core material of ceramic material as described in any one of claims 1 to 7, or the plate-shaped core material of ceramic material prepared by the preparation method described in claim 8.

10. The application of the vacuum insulation panel of claim 9 in zero-carbon buildings, passive houses, cold chain logistics of fruits and vegetables, cold chain logistics vehicle panels, cold storage wall panels, and ultra-thin energy-saving refrigerator insulation layers.

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