A heat-preservation and load-carrying integrated hard felt, a preparation method and application thereof

Abstract

This invention provides an integrated thermal insulation and load-bearing rigid felt, its preparation method, and its application. The preparation method first involves impregnating one surface of a composite rigid felt in resin, then curing and carbonizing the resin-impregnated surface, repeating the above steps of impregnation, curing, and carbonization to obtain an impregnated composite rigid felt. Then, the obtained impregnated composite rigid felt is graphitized to obtain the integrated thermal insulation and load-bearing rigid felt. The preparation method is simple to operate and uses composite rigid felt as the substrate, resulting in lower costs and avoiding the use of high-cost carbon fiber preforms. Furthermore, the prepared integrated thermal insulation and load-bearing rigid felt possesses excellent thermal insulation and corrosion resistance, and can replace the traditional composite structure of carbon-carbon insulation cylinders and insulation layers, making it easier to install during use.

Description

Technical Field

[0001] This invention belongs to the field of thermal insulation materials technology, specifically relating to an integrated thermal insulation and load-bearing rigid felt, its preparation method, and its application. Background Technology

[0002] Carbon-carbon composite materials are particularly suitable for use as high-temperature thermal field components and thermal insulation materials because their high-temperature resistance meets the thermal field insulation requirements of high-temperature crystal growth, and they have the characteristics of low heat capacity, energy saving, durability and no pollution. They can be widely used in high-temperature thermal fields such as solar polycrystalline silicon furnaces, monocrystalline silicon furnaces, and semiconductor furnaces.

[0003] Currently, thermal insulation cylinders for thermal field components are generally made of carbon / carbon composite materials. CN218378368U discloses a novel carbon / carbon composite insulation felt, comprising multiple sheet-like main bodies. Each main body consists of a carbon / carbon composite outer layer, a skeleton layer, a carbon / carbon composite inner layer, and a sealing strip. The skeleton layer has two corresponding snap-fit ​​structures at both ends. The carbon / carbon composite outer layer and the carbon / carbon composite inner layer each have protrusions and grooves corresponding to the two snap-fit ​​structures at both ends. After two adjacent main bodies are snapped together, the protrusions and grooves cooperate to seal the connection between the two skeleton layers. The insulation felt provided by this utility model is simpler and more reliable to install and connect, and the connection between the two main bodies can maintain a good insulation effect. CN217647811U discloses a splicing carbon / carbon insulation cylinder clamping device, including a graphite ring with a diameter larger than that of the splicing carbon / carbon insulation cylinder. At least two bolt holes are evenly spaced on the graphite ring, and each bolt hole is threaded with a graphite bolt. A graphite top block is movably connected to the graphite bolt placed inside the graphite ring to expand the contact surface between the graphite bolt and the splicing carbon / carbon insulation cylinder. This utility model provides a compact splicing carbon / carbon insulation cylinder clamping device that reduces space occupation after entering the high-temperature sintering furnace. The use of graphite material resists thermal deformation caused by high temperatures and has a long service life.

[0004] However, regardless of whether it is an integral thermal field component or a spliced ​​thermal field component, the raw material is carbon fiber preform, which has high production cost and insufficient corrosion resistance. Moreover, the insulation cylinder of carbon / carbon thermal field components generally needs to be wrapped with soft felt or set with hard felt to form thermal insulation material, making the structure very complex.

[0005] Therefore, developing a method for preparing an integrated thermal insulation and load-bearing rigid felt using low-cost rigid felt as the raw material, to replace the existing composite structure of carbon / carbon thermal field components plus thermal insulation soft / rigid felt, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an integrated thermal insulation and load-bearing rigid felt, its preparation method, and its application. The preparation method uses low-cost composite rigid felt as the raw material, resulting in a lower overall cost. Furthermore, the prepared integrated thermal insulation and load-bearing rigid felt exhibits excellent thermal insulation and corrosion resistance, meeting the requirements for use as a thermal field component.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing an integrated thermal insulation and load-bearing rigid felt, the method comprising the following steps:

[0009] (1) Impregnate one side of the composite hard felt in resin, and then cure and carbonize the resin-impregnated side of the composite hard felt. Repeat the above steps of impregnation, curing and carbonization to obtain impregnated composite hard felt.

[0010] (2) The impregnated composite hard felt obtained in step (1) is graphitized to obtain the integrated thermal insulation hard felt.

[0011] The method for preparing the integrated thermal insulation and load-bearing rigid felt provided by the present invention firstly impregnates one side of the composite rigid felt with resin, and then performs curing and carbonization treatment on the resin-impregnated side of the composite rigid felt, so that the density of the resin-impregnated side of the composite rigid felt gradually increases, thereby effectively improving the corrosion resistance and thermal insulation properties of the composite rigid felt. Then, the impregnated composite rigid felt is graphitized to obtain the integrated thermal insulation and load-bearing rigid felt.

[0012] The method for preparing the integrated thermal insulation and load-bearing rigid felt provided by this invention uses composite rigid felt as the base material, which has a lower cost and avoids the use of high-cost carbon fiber preforms. Moreover, the prepared integrated thermal insulation and load-bearing rigid felt has both excellent thermal insulation and corrosion resistance, and can replace the traditional composite structure of carbon / carbon insulation cylinder with insulation layer, making it easier to install during use.

[0013] In the preparation method provided by the present invention, the composite hard felt in step (1) can be obtained by bonding soft felt layer by layer and then impregnating and curing it, or it can be obtained by directly bonding existing hard felt layer by layer.

[0014] Preferably, the density of the rigid felt is 0.17–0.25 g / cm³. 3 For example, 0.18 g / cm³ 3 0.19g / cm 3 0.2g / cm 3 0.21g / cm 3 0.22g / cm 3 0.23g / cm 3Or 0.24g / cm 3 wait.

[0015] Preferably, the density of the soft felt is 0.1–0.15 g / cm³. 3 For example, 0.11 g / cm³ 3 0.12g / cm 3 0.13g / cm 3 Or 0.14 g / cm 3 wait.

[0016] Preferably, the soft felt is a PAN-based soft felt.

[0017] The present invention does not impose a special limitation on the thickness of the provided composite hard felt; it can be prepared according to actual needs.

[0018] Preferably, the resin in step (1) includes any one or a combination of at least two of phenolic resin, epoxy resin, furan resin or organosilicon resin, and more preferably phenolic acid resin.

[0019] Preferably, the solid content of the resin in step (1) is 35% to 75%, such as 40%, 45%, 50%, 55%, 60%, 65%, or 70%.

[0020] Preferably, the impregnation depth of the composite hard felt in the resin in step (1) is 8 to 10 mm, such as 8.2 mm, 8.4 mm, 8.6 mm, 8.8 mm, 9 mm, 9.2 mm, 9.4 mm, 9.6 mm or 9.8 mm.

[0021] Preferably, the impregnation time of the resin in step (1) is 0.5 to 6 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours or 5 hours.

[0022] Preferably, the curing temperature in step (1) is 120 to 200°C, such as 130°C, 140°C, 150°C, 160°C, 170°C, 180°C or 190°C.

[0023] Preferably, the curing time in step (1) is 0.5 to 8 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours or 7 hours.

[0024] Preferably, the carbonization temperature in step (1) is 800 to 1000°C, such as 820°C, 840°C, 860°C, 880°C, 900°C, 920°C, 940°C, 960°C or 980°C.

[0025] Preferably, the carbonization treatment time in step (1) is 1 to 3 hours, such as 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours or 2.8 hours.

[0026] Preferably, the number of repetitions in step (1) is 4 to 8 times, for example, 5, 6 or 7 times.

[0027] Preferably, the mass percentage of resin added to one side of the composite hard felt after the impregnation in a single step (1) is 10% to 50%, for example, 15%, 20%, 25%, 30%, 35%, 40%, 48%, 49%, or 50%.

[0028] Preferably, the graphitization temperature in step (2) is 1800 to 2300°C, such as 1850°C, 1900°C, 1950°C, 2000°C, 2050°C, 2100°C, 2150°C, 2200°C, or 2250°C.

[0029] Preferably, the graphitization treatment time in step (2) is 0.5 to 6 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours or 5 hours.

[0030] As a preferred technical solution, the preparation method of the integrated thermal insulation and load-bearing rigid felt includes the following steps:

[0031] (1) Impregnate one side of the composite hard felt in resin for 0.5 to 6 hours, with an impregnation depth of 8 to 10 mm. After a single impregnation, the mass percentage of resin added to the resin-impregnated side of the composite hard felt is 10 to 50%. Then, cure the resin-impregnated side at 120 to 200°C for 0.5 to 8 hours, and then carbonize it at 800 to 1000°C for 1 to 3 hours. Repeat the above steps of impregnation, curing and carbonization 4 to 8 times to obtain the impregnated composite hard felt.

[0032] (2) The impregnated composite hard felt obtained in step (1) is graphitized at 1800-2300℃ for 0.5-6h to obtain the integrated thermal insulation and load-bearing hard felt.

[0033] In a second aspect, the present invention provides an integrated thermal insulation and load-bearing rigid felt, which is prepared by the preparation method described in the first aspect.

[0034] Preferably, the thickness of the integrated thermal insulation and load-bearing rigid felt is 50-200mm, such as 70mm, 90mm, 110mm, 130mm, 150mm, 170mm or 190mm.

[0035] Preferably, the density of the resin-impregnated surface of the integrated thermal insulation and load-bearing rigid felt is 0.8–1.7 g / cm³. 3 For example, 0.9 g / cm³ 3 1g / cm 3 1.1g / cm 31.2g / cm 3 1.3g / cm 3 1.4g / cm 3 1.5g / cm 3 Or 1.6g / cm 3 wait.

[0036] It should be noted that the "resin-impregnated surface of the integrated thermal insulation and load-bearing rigid felt" mentioned above refers to the corresponding part after being impregnated with resin and cured, carbonized and graphitized.

[0037] Thirdly, the present invention provides a thermal field component, which is made of spliced ​​integrated thermal insulation and load-bearing rigid felt as described in the second aspect.

[0038] The thermal field component provided by this invention is spliced ​​from an integrated thermal insulation and load-bearing rigid felt. The final spliced ​​thermal field component can be a flat shape or a curved shape. If the spliced ​​component is a curved shape, a curved mold is used to make the rigid felt curved during the process of turning the soft felt into a hard felt.

[0039] Fourthly, the present invention provides the application of the thermal field component as described in the third aspect in a solar polycrystalline silicon furnace, a monocrystalline silicon furnace, or a semiconductor furnace.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The main advantage of the method for preparing integrated thermal insulation and load-bearing rigid felt provided by this invention is that it directly prepares integrated thermal insulation and load-bearing rigid felt using composite rigid felt as the base material. This integrated thermal insulation and load-bearing rigid felt can be directly used as a thermal field component and can replace the original two-layer insulation structure of carbon / carbon insulation cylinders combined with soft felt (or rigid felt). It also has the following three advantages:

[0042] (1) After repeatedly impregnating the composite hard felt with resin and curing and carbonizing it, a high-density hard felt structure layer is obtained. This structure layer can fully achieve the mechanical load-bearing performance level of carbon / carbon thermal field components. Using composite hard felt as the base material avoids the use of high-cost carbon fiber preforms. The cost is only 1 / 3 of the current cost of carbon / carbon insulation cylinders, which significantly reduces product cost.

[0043] (2) Existing carbon / carbon insulation cylinders with soft felt (or hard felt) are assembled structures. The process of loading the insulation cylinder into the furnace or taking it out of the high-temperature furnace is cumbersome. For example, when loading the furnace, the carbon / carbon insulation cylinder needs to be assembled first, and then the soft felt or hard felt needs to be wrapped. However, the integrated insulation and load-bearing hard felt provided by the present invention is a whole, which greatly improves the convenience of operation and avoids the impact of improper assembly on insulation performance.

[0044] (3) The integrated thermal insulation and load-bearing rigid felt prepared by the preparation method provided by this invention has both excellent thermal insulation and corrosion resistance. During use in the hot zone of a crystalline silicon furnace, traditional carbon / carbon insulation components are subject to corrosion by silicon vapor. Since the carbon fiber preform used in the carbon / carbon insulation method has a density of approximately 0.6 g / cm³, the insulation is superior. 3 Therefore, carbon / carbon composites contain a relatively high amount of carbon fibers. These carbon fibers become brittle after being corroded by silicon, leading to a decrease in the mechanical properties of the component and even load-bearing failure. In contrast, the density of the resin-impregnated surface of the integrated thermal insulation and load-bearing rigid felt provided by this invention is 0.17–0.25 g / cm³. 3 After repeated impregnation with resin and carbonization, the material contains a large amount of matrix resin carbon. The resin carbon is loosely distributed, and after being corroded by silicon, it will not cause a precipitous impact on the overall mechanical properties of the component. Therefore, its corrosion resistance is better than that of carbon / carbon components. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the impregnation of composite rigid felt in resin;

[0046] Figure 2 A schematic cross-sectional view of a conventional carbon / carbon insulation component provided for Comparative Example 1;

[0047] Among them, 1-composite rigid felt, 2-resin, 3-carbon / carbon layer, 4-rigid felt layer. Detailed Implementation

[0048] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0049] The following is some information about the raw materials involved in the specific embodiments of this invention:

[0050] Phenolic resin: solid content 70%, BR2130 type;

[0051] Epoxy resin: 50% solids content, type E51;

[0052] PAN-based soft felt: density 0.12 g / cm³ 3 .

[0053] Examples 1-8

[0054] A method for preparing an integrated thermal insulation and load-bearing rigid felt, the method comprising the following steps:

[0055] (1) Bonding multiple layers of PAN-based soft felt together and then wetting and curing them, or directly bonding multiple layers of PAN-based hard felt together to obtain composite hard felt;

[0056] (2) Impregnate one side surface of the composite rigid felt obtained in step (1) in resin (e.g. Figure 1 As shown, Figure 1 This is a schematic diagram of the composite hard felt being impregnated in resin, where 1 represents the composite hard felt, 2 represents the resin, and D represents the impregnation depth. Then, the surface of the composite hard felt impregnated with resin is cured and carbonized. The above steps of impregnating with resin, curing and carbonizing are repeated to obtain the impregnated composite hard felt.

[0057] (3) The impregnated composite hard felt obtained in step (2) is graphitized to obtain the integrated thermal insulation and load-bearing hard felt.

[0058] The parameter information involved in each step of the preparation method of the integrated thermal insulation and load-bearing rigid felt provided in Examples 1 to 8 is shown in Table 1:

[0059] Table 1

[0060]

[0061]

[0062] Comparative Example 1

[0063] A schematic diagram of the cross-sectional structure of a traditional carbon / carbon insulation component is shown below. Figure 2 As shown, it consists of an inner carbon / carbon layer 3 and an outer hard felt layer 4.

[0064] Comparative Example 2

[0065] A method for preparing an integrated thermal insulation rigid felt differs from Example 1 only in that it does not involve impregnation and curing, but is directly carbonized at 900°C for 2 hours and then graphitized at 2000°C for 3 hours to obtain the thermal insulation rigid felt.

[0066] Performance testing:

[0067] (1) Thermal insulation: A sample was taken from one side of the resin-impregnated rigid felt for thermal insulation and load bearing, and the thermal conductivity was tested using a thermal conductivity analyzer.

[0068] (2) Corrosion resistance: The thermal insulation and load-bearing integrated hard felt was made into a thermal field component, and the thickness of silicon vapor erosion was observed after 360 days of use;

[0069] (3) Compressive strength: A sample was taken from one side of the resin-impregnated rigid felt for thermal insulation and load bearing, with a sample thickness of 10 mm. The compressive strength of the sample was tested using an electronic universal testing machine.

[0070] (4) Density: A sample was taken from the surface of the integrated thermal insulation and load-bearing rigid felt impregnated with resin, and the density was tested by weighing.

[0071] The products obtained in Examples 1-8 and Comparative Examples 1-2 were tested according to the above test methods, and the test results are shown in Table 1:

[0072] Table 1

[0073]

[0074] According to the data in Table 1:

[0075] The integrated thermal insulation and load-bearing rigid material prepared by the preparation method provided in this invention has excellent thermal insulation performance, mechanical properties and corrosion resistance.

[0076] Specifically, the overall compressive strength of the integrated thermal insulation and load-bearing rigid felt provided in Examples 1-3 is above 147-163 MPa, which is significantly higher than the general strength level of traditional carbon / carbon thermal field components. Furthermore, the density of the resin-impregnated surface of the integrated thermal insulation and load-bearing rigid felt provided in Examples 1-3 is 1.49-1.61 g / cm³. 3 It can completely replace carbon / carbon components to achieve the load-bearing function; at the same time, the thermal conductivity of the resin-impregnated surface of the integrated thermal insulation and load-bearing rigid felt provided in Examples 1-3 is only 10-14 W·m. -1 ·K -1 This ensures good thermal insulation performance, while the other side maintains the thermal insulation performance of traditional soft or hard felt. In addition, under the same conditions, the integrated thermal insulation and load-bearing hard felt provided in Examples 1 to 3 is less susceptible to silicon vapor erosion, with an erosion thickness of only 16 to 25 μm, which can effectively extend the service life of the product.

[0077] Comparing Example 1 and Comparative Examples 1-2, it can be seen that the traditional carbon / carbon insulation component (Comparative Example 1) has a generally low compressive strength, and a high thermal conductivity and silicon vapor erosion thickness, indicating that its insulation and corrosion resistance are insufficient; while the composite hard felt without resin impregnation treatment has very poor compressive strength and cannot be used as a thermal field component.

[0078] Comparing the data from Examples 1 and 4-5, it can be seen that the resin impregnation depth is too shallow and cannot achieve the bearing effect; while the impregnation depth of 15mm and 10mm have the same effect, so in actual operation, it is only necessary to limit the impregnation depth to 8-10mm.

[0079] Further comparison of the data from Examples 1 and 6-7 reveals that too few impregnations will not achieve the desired load-bearing effect, while too many impregnations will not improve the effect and will instead waste time.

[0080] Finally, comparing the data from Example 1 and Example 8, it can be seen that using phenolic resin as the impregnation resin has a better densification effect than using epoxy resin as the impregnation resin.

[0081] In summary, the thermal field component made of the integrated thermal insulation and load-bearing rigid felt prepared by the preparation method provided by this invention can replace the original two-layer insulation structure of carbon / carbon insulation cylinder plus soft felt (or rigid felt), greatly improving the convenience of operation and reducing costs.

[0082] The applicant declares that this invention illustrates an integrated thermal insulation and load-bearing rigid felt, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above process steps, meaning that this invention does not necessarily rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials used in this invention, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A method for preparing an integrated thermal insulation and load-bearing rigid felt, characterized in that, The preparation method includes the following steps: (1) Impregnate one side of the composite hard felt in resin, and then cure and carbonize the resin-impregnated side of the composite hard felt. Repeat the above steps of impregnation, curing and carbonization to obtain impregnated composite hard felt. (2) The impregnated composite hard felt obtained in step (1) is subjected to graphitization treatment to obtain the integrated thermal insulation and load-bearing hard felt; The number of repetitions in step (1) is 4 to 8 times; In step (1), the impregnation depth of the composite rigid felt in the resin is 8~10 mm; The composite hard felt in step (1) is obtained by bonding multiple layers of soft felt together and then impregnating and curing them; or, the composite hard felt is obtained by bonding multiple layers of hard felt together; the density of the hard felt is 0.17~0.25 g / cm³. 3 The density of the soft felt is 0.1~0.15 g / cm³. 3 ; The density of the resin-impregnated surface of the integrated thermal insulation and load-bearing rigid felt is 0.8~1.7 g / cm³. 3 .

2. The preparation method according to claim 1, characterized in that, The resin in step (1) includes any one or a combination of at least two of phenolic resin, epoxy resin, furan resin or organosilicon resin.

3. The preparation method according to claim 2, characterized in that, The resin mentioned in step (1) is a phenolic resin.

4. The preparation method according to claim 1, characterized in that, The solid content of the resin in step (1) is 35-75%.

5. The preparation method according to claim 1, characterized in that, The resin impregnation time in step (1) is 0.5~6h.

6. The preparation method according to claim 1, characterized in that, The curing temperature in step (1) is 120~200℃.

7. The preparation method according to claim 1, characterized in that, The curing time in step (1) is 0.5~8h.

8. The preparation method according to claim 1, characterized in that, The carbonization temperature in step (1) is 800~1000℃.

9. The preparation method according to claim 1, characterized in that, The carbonization process in step (1) takes 1 to 3 hours.

10. The preparation method according to claim 1, characterized in that, After the resin impregnation in step (1) is completed, the added resin mass percentage on one side of the composite hard felt is 10~50%.

11. The preparation method according to claim 1, characterized in that, The temperature for graphitization in step (2) is 1800~2300℃.

12. The preparation method according to claim 1, characterized in that, The graphitization process in step (2) takes 0.5 to 6 hours.

13. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: (1) Impregnate one side of the composite hard felt in resin for 0.5-6 h, with an impregnation depth of 8-10 mm. After a single impregnation, the mass percentage of resin added to the resin-impregnated side of the composite hard felt is 10-50%. Then, cure the resin-impregnated side of the composite hard felt at 120-200℃ for 0.5-8 h, and then carbonize it at 800-1000℃ for 1-3 h. Repeat the above steps of impregnation, curing and carbonization 4-8 times to obtain impregnated composite hard felt. (2) The impregnated composite hard felt obtained in step (1) is graphitized at 1800~2300℃ for 0.5~6 h to obtain the integrated thermal insulation and load-bearing hard felt.

14. A thermal insulation and load-bearing integrated rigid felt, characterized in that, The integrated thermal insulation and load-bearing rigid felt is prepared using the preparation method described in any one of claims 1 to 13.

15. The integrated thermal insulation and load-bearing rigid felt according to claim 14, characterized in that, The thickness of the integrated thermal insulation and load-bearing rigid felt is 50~200 mm.

16. A thermal field component, characterized in that, The thermal field component is made of spliced ​​integrated thermal insulation and load-bearing rigid felt as described in claim 14 or 15.

17. The application of the thermal field component as described in claim 16 in a solar polycrystalline silicon furnace, a monocrystalline silicon furnace, or a semiconductor furnace.

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