Carbon-carbon thermal insulation hard felt with gradient density distribution and its application

Abstract

The present invention provides a carbon-carbon thermal insulation hard felt with a gradient density distribution and its application, and relates to the field of material technology. The carbon-carbon thermal insulation hard felt provided by the present invention is mainly prepared by sequentially subjecting soft felt to glue spray curing, stacking hot pressing, glue carbonization treatment and high-temperature treatment. The carbon-carbon thermal insulation hard felt has a gradient density distribution, and adopts phased oblique needle punching between soft felt layers to make the heat transfer channel between carbon-carbon thermal insulation hard felt layers longer and less connected, so that the carbon-carbon thermal insulation hard felt has a higher density on the inner side in the thermal field, which improves durability, and a lower density on the outer side, which plays a role in heat preservation. Without increasing production costs, the service life of the carbon-carbon thermal insulation hard felt is increased, and the thermal insulation performance is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of materials, and in particular to a carbon-carbon thermal insulation hard felt with gradient density distribution and application thereof. Background Art

[0002] At present, the general density of carbon-carbon thermal insulation felt is between 0.18-0.21g / cm³, and the thermal conductivity is between 0.2W / (m·K)-0.4W / (m·K). The performance parameter of the thermal insulation performance of carbon-carbon thermal insulation felt is reflected in the thermal conductivity. The lower the thermal conductivity of carbon-carbon thermal insulation felt, the better the thermal insulation performance. To reduce the thermal conductivity of carbon-carbon thermal insulation felt, there are two main directions: first, reduce the density of carbon-carbon thermal insulation felt, and second, reduce the heat transfer channel of carbon-carbon thermal insulation felt. Of the two directions, the second direction is prone to stratification and other problems that will lead to product scrapping, so the main improvement direction is to reduce the density of carbon-carbon thermal insulation felt.

[0003] Lowering the density of carbon-carbon thermal insulation felt will directly lead to lower strength of the carbon-carbon thermal insulation felt, thereby reducing the service life of the carbon-carbon thermal insulation felt. Therefore, in the process of improving the thermal insulation performance by reducing the density of carbon-carbon thermal insulation felt, stronger carbon fibers will be used to make the carbon-carbon thermal insulation felt, which undoubtedly greatly increases the production cost of the carbon-carbon thermal insulation felt, and through this method, the service life of the carbon-carbon thermal insulation felt is also minimally improved.

[0004] The existing carbon-carbon thermal insulation hard felt has a relatively uniform density distribution of its base as a whole. However, during installation in a thermal field, the carbon-carbon thermal insulation hard felt is installed upright in the thermal field with one side facing outward and the other side facing inward. Due to the low density of its base, the inward side is corroded by various gases inside the thermal field and burned by high temperature, and this side is more easily damaged. Therefore, the service life of the carbon-carbon thermal insulation hard felt is generally short. Moreover, due to its density limitation, the thermal conductivity cannot be further reduced, resulting in the inability to further improve the thermal insulation performance of the carbon-carbon thermal insulation hard felt.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The first purpose of the present invention is to provide a carbon-carbon thermal insulation hard felt with a gradient density distribution, so as to solve the problem that the carbon-carbon thermal insulation hard felt has a short service life and cannot be combined with high performance.

[0007] The second object of the present invention is to provide the application of the above-mentioned carbon-carbon thermal insulation hard felt in thermal insulation.

[0008] In order to achieve the above objectives, the following technical solutions are adopted:

[0009] In a first aspect, the present invention provides a carbon-carbon thermal insulation hard felt, which is mainly prepared by sequentially subjecting a soft felt to glue spray curing, stacking hot pressing, glue carbonization treatment and high temperature treatment;

[0010] The carbon-carbon thermal insulation hard felt comprises at least two groups of soft felts, and the density gradient of each group of soft felts increases from one side to the other side of the carbon-carbon thermal insulation hard felt;

[0011] Each set of soft felt includes at least 1 piece of soft felt;

[0012] Each piece of soft felt is obtained by needling 3 groups of mesh tires, and the needling angle of each group of mesh tires is 30°-60°, and the needling directions of adjacent groups of mesh tires are opposite;

[0013] Each set of mesh tires includes at least 2 pieces of carbon fiber mesh tires;

[0014] The temperature of the high temperature treatment is 2100-2300°C.

[0015] As a further technical solution, the spray curing includes: spraying phenolic resin on the surface of each soft felt, and then baking and curing.

[0016] As a further technical solution, the phenolic resin includes 0371 phenolic resin.

[0017] As a further technical solution, the stacking and hot pressing comprises: spraying phenolic resin on the upper surface of each soft felt, stacking the soft felts according to their density, and then subjecting them to hot pressing treatment to obtain a cured felt.

[0018] As a further technical solution, the phenolic resin includes 0371 phenolic resin.

[0019] As a further technical solution, the glue carbonization treatment includes: subjecting the cured felt to a carbonization treatment so as to carbonize the phenolic resin to obtain a carbon felt.

[0020] As a further technical solution, the carbon fiber web is obtained by needle punching carbon fiber chopped strands;

[0021] The length of the carbon fiber chopped strands is 75-85 mm.

[0022] As a further technical solution, the carbon fiber mesh has a gram weight of 60-80 g / m 2 .

[0023] As a further technical solution, the carbon-carbon thermal insulation hard felt includes 3 groups of soft felts, each group of soft felts includes 3 pieces of soft felts, and the soft felt densities of the 3 groups of soft felts are 0.09g / cm³, 0.14g / cm³ and 0.19g / cm³ respectively.

[0024] In a second aspect, the present invention provides the use of the above-mentioned carbon-carbon thermal insulation hard felt in thermal insulation.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The carbon-carbon thermal insulation hard felt provided by the present invention has a gradient density distribution, and adopts staged oblique needling between soft felt layers to make the heat transfer channels between the carbon-carbon thermal insulation hard felt layers longer and have fewer connections, so that the carbon-carbon thermal insulation hard felt has a higher density on the inner side in the thermal field, which improves durability, and a lower density on the outer side, which plays a thermal insulation role. Without increasing production costs, the service life of the carbon-carbon thermal insulation hard felt is increased, and the thermal insulation performance is further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is the needle punching direction of each group of mesh in the soft felt;

[0029] Figure 2 It is a soft felt structure after needle punching. DETAILED DESCRIPTION

[0030] The embodiments of the present invention will be described in detail below in conjunction with the embodiments and examples, but it will be appreciated by those skilled in the art that the following embodiments and examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified, proceed according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0031] In a first aspect, the present invention provides a carbon-carbon thermal insulation hard felt, which is mainly prepared by sequentially subjecting a soft felt to glue spray curing, stacking hot pressing, glue carbonization treatment and high temperature treatment;

[0032] The carbon-carbon thermal insulation hard felt comprises at least two groups of soft felts, and the density gradient of each group of soft felts increases from one side to the other side of the carbon-carbon thermal insulation hard felt (the density of a single piece of soft felt can be controlled by changing the needle density and the weight of a single piece of soft felt);

[0033] Each set of soft felt includes at least 1 piece of soft felt;

[0034] Each piece of soft felt is obtained by needling 3 groups of mesh tires, and the needling angle of each group of mesh tires is 30°-60°, and the needling directions of adjacent groups of mesh tires are opposite;

[0035] Each set of mesh tires includes at least 2 pieces of carbon fiber mesh tires;

[0036] The temperature of the high temperature treatment may be, for example, but not limited to, 2100°C, 2200°C or 2300°C.

[0037] It should be noted that, in the present invention, "the needling directions of adjacent groups of mesh tires are relative" means that the carbon-carbon thermal insulation hard felt includes multiple groups of mesh tires. If the needling direction of a group of mesh tires is from upper right to lower left, then the needling direction of the upper or lower layer mesh tire group adjacent to it is from upper left to lower right.

[0038] The carbon-carbon thermal insulation hard felt provided by the present invention is that without increasing the production cost, by changing the density distribution and the needling process of the carbon-carbon thermal insulation hard felt, the areas on the carbon-carbon thermal insulation hard felt are differentiated for different usage environments, thereby maintaining or even extending the service life and improving the thermal insulation performance.

[0039] In some optional implementations, the spray curing includes: spraying phenolic resin on the surface of each soft felt, and then baking and curing.

[0040] In the present invention, the spraying amount of the phenolic resin is calculated according to the preset density of the soft felt and the weight of a single piece of soft felt. The density of a single piece of soft felt is different, and the content of the phenolic resin sprayed is also different.

[0041] In some optional embodiments, the phenolic resin includes but is not limited to 0371 phenolic resin, or other phenolic resins known to those skilled in the art.

[0042] In some optional embodiments, the stacking and hot pressing comprises: spraying phenolic resin on the upper surface of each soft felt, stacking the soft felts according to their density, and then performing hot pressing to obtain a cured felt.

[0043] In some optional embodiments, the amount of phenolic resin sprayed on the upper surface of each piece of soft felt is the same.

[0044] In some optional embodiments, the phenolic resin includes but is not limited to 0371 phenolic resin, or other phenolic resins known to those skilled in the art.

[0045] In some optional embodiments, the glue carbonization treatment includes: subjecting the cured felt to a carbonization treatment to carbonize the phenolic resin to obtain a carbon felt.

[0046] In some optional embodiments, the carbon fiber web is obtained by needle punching carbon fiber chopped strands;

[0047] The length of the carbon fiber chopped strands is 75-85 mm.

[0048] In some optional embodiments, the carbon fiber mesh has a gram weight of 60-80 g / m 2 .

[0049] In some optional embodiments, the carbon-carbon thermal insulation hard felt includes 3 groups of soft felts, each group of soft felts includes 3 pieces of soft felts, and the soft felt densities of the 3 groups of soft felts are 0.09g / cm³, 0.14g / cm³ and 0.19g / cm³ respectively.

[0050] In a second aspect, the present invention provides the use of the above-mentioned carbon-carbon thermal insulation hard felt in thermal insulation.

[0051] The carbon-carbon thermal insulation hard felt provided by the invention has more excellent thermal insulation performance and can therefore be used in thermal insulation.

[0052] The present invention is further described below by means of specific examples and comparative examples. However, it should be understood that these examples are only used for more detailed description and should not be construed as limiting the present invention in any form.

[0053] Example 1

[0054] A carbon-carbon thermal insulation hard felt, the process route of which is: carbon fiber chopped - web carding and compounding - material preparation - soft felt needle punching - glue spraying and curing - hot pressing of layering - carbonization - high temperature - finished product.

[0055] The specific preparation method is as follows:

[0056] Carbon fiber chopped and web combing compound: The carbon fiber is chopped into short strands (short strand length 80±5mm), opened and combed, and needled into a web (web surface weight 70±10g / m 2 ) and prepare the web tire according to the preset soft felt density (0.14g / cm³).

[0057] Material preparation: The mesh tire cutting size is cut according to the specifications of the soft felt blank, and the number of mesh tire pieces required for a single piece of soft felt is prepared based on the weight of a single piece of soft felt.

[0058] Soft felt needle punching: Taking 0.14g / cm³ as the target density, the soft felt required for carbon-carbon thermal insulation hard felt is divided into 3 groups. The density of each group of soft felt varies from low to high. Each group of soft felt includes 3 pieces of soft felt. The density of each group of soft felt is 0.09g / cm³, 0.14g / cm³ and 0.19g / cm³.

[0059] Adjustment of soft felt needle punching process: add oblique needle punching process to the original soft felt needle punching process (one piece of soft felt needs 3 layering processes and 3 needle punching processes), divide each piece of soft felt into 3 groups during the layering process. The first group includes 3 pieces of mesh, the second group includes 4 pieces of mesh, and the third group includes 5 pieces of mesh. Figure 1 As shown, the needling angle of the first group is 30°, the needling angle of the second group is 45°, and the needling angle of the third group is 60°. The oblique needling direction of the first group is opposite to the oblique needling direction of the second group, and the third group is the same as the second group. The second group is needled on the basis of the third group, and the first group is needled on the basis of the second group. After needling, the soft felt formed is as follows Figure 2 shown.

[0060] Glue spraying and curing: After the soft felt is needle-punched, it is sprayed with glue. The soft felt is pushed into the glue spraying device and 0371 phenolic resin is sprayed on the surface of the soft felt. After the glue spraying is completed, the soft felt is pushed into the oven for baking.

[0061] Laying and hot pressing: After the soft felt is cured, each piece of soft felt in a group of soft felts is stacked according to its density, from top to bottom. 9501 phenolic resin is sprayed on the upper surface of each soft felt (the amount of 9501 phenolic resin sprayed on each layer is equal and uniform). After the 9501 resin is sprayed on the upper surface of the soft felt and the stacking is completed, the group of soft felts is sent to the press for hot pressing. After the hot pressing is completed, the soft felt becomes a cured felt.

[0062] Carbonization: The cured felt is placed in a carbonization furnace for carbonization treatment, so that the phenolic resin in the cured felt is carbonized in a high temperature environment. After carbonization, the cured felt becomes carbon felt.

[0063] High temperature: The carbon felt is placed in a high temperature furnace at 2200°C for high temperature treatment. After high temperature treatment, the carbon-carbon thermal insulation hard felt is produced with a thickness of 60mm.

[0064] Comparative Example 1

[0065] The difference from Example 1 is that the density of each soft felt is the same, which is 0.14 g / cm³, and does not have a gradient distribution structure.

[0066] Comparative Example 2

[0067] The difference from Example 1 is that each piece of soft felt is punched using a conventional needle punching process (the needle punching angle is 90°).

[0068] Test Example 1

[0069] The density, thermal conductivity and bending strength of the carbon-carbon thermal insulation hard felt provided in Example 1 and Comparative Examples 1-2 were tested.

[0070] The test samples for the three properties were taken from the upper, middle and lower positions of the carbon-carbon thermal insulation felt.

[0071] After the three performance tests were completed, the experimental data were obtained as shown in Tables 1 to 3.

[0072] Table 1 Test data of carbon-carbon thermal insulation hard felt of Example 1.

[0073] .

[0074] Table 2 Test data of carbon-carbon thermal insulation hard felt of comparative example 1.

[0075] .

[0076] Table 3 Test data of carbon-carbon thermal insulation hard felt of comparative example 2

[0077] .

[0078] The data in the above table show that this carbon-carbon thermal insulation hard felt has successfully achieved the expected design goals and realized a stepped distribution of the hard felt matrix density from one side to the other. At the same time, on the side with low density, its thermal conductivity is lower and its thermal insulation performance is better. On the side with high density, its bending strength is higher and its service life is longer.

[0079] It is proved that this carbon-carbon thermal insulation hard felt has a longer service life and better thermal insulation performance than ordinary carbon-carbon thermal insulation hard felt.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A carbon-carbon thermal insulation hard felt, characterized in that: It is mainly prepared by soft felt through spray curing, stacking and hot pressing, glue carbonization and high temperature treatment. The carbon-carbon thermal insulation hard felt comprises three groups of soft felts, and from one side to the other side of the carbon-carbon thermal insulation hard felt, the soft felt densities of the three groups of soft felts are 0.09 g / cm³, 0.14 g / cm³ and 0.19 g / cm³ respectively; Each set of soft felt includes 3 pieces of soft felt; Each piece of soft felt is obtained by needling 3 groups of mesh tires, and the needling angle of each group of mesh tires is 30°-60°, and the needling directions of adjacent groups of mesh tires are opposite; Each set of mesh tires includes at least 2 pieces of carbon fiber mesh tires; The temperature of the high temperature treatment is 2100-2300°C.

2. The carbon-carbon thermal insulation hard felt according to claim 1, characterized in that: The spray curing comprises: spraying phenolic resin on the surface of each soft felt, and then baking and curing.

3. The carbon-carbon thermal insulation hard felt according to claim 2, characterized in that: The phenolic resin includes 0371 phenolic resin.

4. The carbon-carbon thermal insulation hard felt according to claim 1, characterized in that: The stacking and hot pressing comprises: spraying phenolic resin on the upper surface of each soft felt, stacking the soft felts according to their density, and then performing hot pressing to obtain a cured felt.

5. The carbon-carbon thermal insulation hard felt according to claim 4, characterized in that: The phenolic resin includes 0371 phenolic resin.

6. The carbon-carbon thermal insulation hard felt according to claim 4 or 5, characterized in that: The glue carbonization treatment includes: performing carbonization treatment on the cured felt to carbonize the phenolic resin to obtain carbon felt.

7. The carbon-carbon thermal insulation hard felt according to claim 1, characterized in that: The carbon fiber web is obtained by needle punching carbon fiber chopped strands; The length of the carbon fiber chopped strands is 75-85 mm.

8. The carbon-carbon thermal insulation hard felt according to claim 7, characterized in that: The carbon fiber mesh has a gram weight of 60-80 g / m 2 .

9. Use of the carbon-carbon thermal insulation felt according to any one of claims 1 to 8 in thermal insulation.

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