Preparation method of composite carbon-carbon heat-insulating hard felt and composite carbon-carbon heat-insulating hard felt prepared thereby

Abstract

The application provides a preparation method of a composite carbon-carbon heat-insulating hard felt and the composite carbon-carbon heat-insulating hard felt prepared by the method, and relates to the technical field of carbon fiber heat-insulating materials. The preparation method comprises the following steps: preparation of a soft felt, preparation of a reinforcing layer, preparation of a composite layer of a buffer layer and the reinforcing layer, preparation of a carbon-carbon heat-insulating felt matrix, preparation of a composite carbon-carbon heat-insulating felt, and preparation of a composite carbon-carbon heat-insulating hard felt. The composite carbon-carbon heat-insulating hard felt prepared by the method has good impact resistance, bending resistance, erosion resistance and low porosity, and the resistance of the carbon-carbon heat-insulating hard felt to high-speed airflow erosion and corrosion during use is greatly enhanced, and the service life of the product is prolonged.

Description

Technical Field

[0001] This invention relates to the field of carbon fiber insulation materials technology, specifically to a method for preparing a composite carbon-carbon insulation rigid felt and the composite carbon-carbon insulation rigid felt prepared therefrom. Background Technology

[0002] Currently, the density of carbon-carbon thermal insulation rigid felt is generally between 0.18 and 0.21 g / cm³. 3 The porosity of carbon-carbon insulating felt ranges from 88% to 89.7%, and its thermal conductivity ranges from 0.2 to 0.4 W / mK. The thermal insulation performance of carbon-carbon insulating felt is primarily reflected in its thermal conductivity; the lower the thermal conductivity, the better the insulation performance. However, carbon-carbon insulating felt with lower thermal conductivity will have a correspondingly higher porosity. In high-temperature environments with furnace pressure, the high porosity of the surface of the carbon-carbon insulating felt leads to the permeation and deposition of production vapors, causing an increase in internal density and a decrease in insulation performance. Furthermore, the long-term erosion of the carbon filaments within the felt by steam eventually results in delamination and voids, affecting the service life of the carbon-carbon insulating felt. In addition, the current production process of traditional carbon-carbon thermal insulation rigid felt is as follows: carbon fiber short cutting - carding - web forming - needle punching reinforcement - soft felt composite - cutting and preparation - layering and hot pressing - carbonization - high temperature - finished product. That is, it is mostly made of pre-oxidized integral felt, and its reinforcement method is integral needle punching molding, with internal fibers in a three-dimensional random distribution.

[0003] If the gas contains elements such as silicon, these elements will penetrate into the carbon-carbon insulation felt under the pressure inside the furnace after use, depositing and reacting on the surface of the carbon filaments. This abnormal reaction and deposition during use will passively increase the density of the low-density carbon-carbon insulation felt, reducing its internal porosity and decreasing its insulation performance. Furthermore, the density difference between the inside and outside of the insulation felt caused by abnormal deposition will result in different coefficients of linear expansion in the inner and outer regions under high-temperature conditions, ultimately leading to delamination and detachment of the carbon-carbon insulation felt.

[0004] On the other hand, the carbon fibers and carbon in the carbon-carbon insulation felt react with the ambient gas in the furnace at high temperatures, causing the ambient gas to chemically corrode the carbon-carbon insulation felt. This reduces the structural strength of the intertwined fiber knots and the strength of the carbon fibers in the carbon-carbon insulation felt, which are formed by overall needle punching and reinforcement, resulting in abnormal powdering and delamination of the product.

[0005] If the environment in which carbon-carbon insulation products are used is mainly composed of elements such as nitrogen and argon, the high-speed flow of gas will cause high-speed erosion of the fiber entanglement points on the surface of the carbon-carbon insulation felt, which is integrally needle-punched. After long-term use, the fiber entanglement points inside the carbon-carbon insulation felt will be damaged, eventually leading to structural damage to the carbon-carbon insulation felt.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing a composite carbon-carbon thermal insulation rigid felt and the composite carbon-carbon thermal insulation rigid felt obtained therefrom. This invention provides a method for preparing a carbon fiber thermal insulation rigid felt that exhibits erosion resistance, corrosion resistance, and a long service life under high temperature and furnace pressure conditions, thereby improving the insufficient service life of traditional ordinary carbon fiber thermal insulation rigid felt under high temperature and high pressure conditions.

[0008] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0009] In a first aspect, the present invention provides a method for preparing a composite carbon-carbon thermal insulation rigid felt, the method comprising:

[0010] Preparation of soft felt: Short-cut carbon fiber filaments are opened and formed into a web to obtain a carbon fiber web; the carbon fiber web is then laid in a Z-shaped reciprocating pattern and reinforced by needle punching to obtain a surface density of 800-1300 g / m². 2 Soft felt;

[0011] Preparation of the reinforcing layer: Short carbon fiber filaments are opened and needle-punched to obtain an areal density of 150-250 g / m². 2 The reinforcing layer mesh is formed by applying a phenolic resin liquid with a carbon content of 40-45% to the surface of a single piece of the reinforcing layer mesh, followed by applying phenolic resin powder with a residual carbon content of 55-60%. The single pieces of mesh after applying the phenolic resin twice are stacked, cured, and pressed to obtain the reinforcing layer.

[0012] Preparation of composite layer: surface density of 1100-1300 g / m² 2 A phenolic resin liquid with a residual carbon content of 46-50% is applied to the surface of the soft felt to cover the reinforcing layer. After curing, a composite layer of buffer layer and reinforcing layer is obtained.

[0013] Preparation of carbon-carbon thermal insulation felt matrix: for single sheet surface density of 800-1100 g / m 2 A phenolic resin liquid with a residual carbon content of 30-35% is applied to both sides of the soft felt. After curing, a phenolic resin liquid with a residual carbon content of 46-50% is applied. The single soft felts with the applied phenolic resin are stacked, cured, and pressed to obtain a carbon-carbon thermal insulation felt matrix.

[0014] Preparation of composite carbon-carbon thermal insulation felt: A phenolic resin liquid with a residual carbon rate of 46-50% is applied to the surface of the carbon-carbon thermal insulation felt matrix, covering the composite layer, and cured to obtain composite carbon-carbon thermal insulation felt;

[0015] Preparation of composite carbon-carbon thermal insulation hard felt: The composite carbon-carbon thermal insulation felt is carbonized and subjected to high temperature treatment to obtain composite carbon-carbon thermal insulation hard felt.

[0016] Preferably, in the preparation process of the soft felt, the chopped carbon fiber filaments are selected from mixed chopped carbon filaments with a length of 40 to 120 mm.

[0017] Preferably, in the mixed chopped carbon filaments: the proportion of chopped carbon filaments with a length < 60 mm is < 50 wt%, and the proportion of chopped carbon filaments with a length > 100 mm is ≥ 10 wt%.

[0018] Preferably, in the preparation process of the soft felt, the opening step includes: stirring the chopped carbon fiber filaments to obtain a preliminary mixed carbon filament; and opening the preliminary mixed carbon filament through a multi-roller opening machine to obtain a mixed carbon filament.

[0019] Preferably, in the opening step of preparing the soft felt, the stirring speed is 65-75 rpm and the stirring time is 3-5 min; the parameters of the multi-roller opening machine include: 4-8 pairs of opening rollers, the frequency of the opening rollers is 10-20 Hz, and the frequency of the cylinder is 40-50 Hz.

[0020] Preferably, in the preparation process of the soft felt, the web-forming step includes: sending the loosened mixed carbon filaments into a cotton box through a high-speed airflow to form fiber clusters, combing them through a high-speed cylinder to form a fiber web, and peeling them off from the high-speed cylinder through negative pressure adsorption to obtain a carbon fiber web.

[0021] Preferably, in the web-forming step of preparing the soft felt, the rotation speed of the high-speed cylinder is 1200-1300 rpm; the negative pressure adsorption is provided by fans on both sides, and the frequency of the fans is 30-40 Hz.

[0022] Preferably, during the preparation of the soft felt, the areal density of the soft felt is 1100–1300 g / m³. 2 At that time, the number of reciprocating layers is 22 to 26, and the density of the needle reinforcement is 15 to 25 needles / cm. 2 .

[0023] Preferably, during the preparation of the soft felt, when the areal density of the soft felt is 800–1100 g / m³ 2 At that time, the number of reciprocating layers is 16 to 22, and the density of the needle reinforcement is 15 to 25 needles / cm. 2 .

[0024] Preferably, during the preparation of the reinforcing layer, the chopped carbon fiber filaments are selected from mixed chopped carbon filaments with a length of 40 to 120 mm.

[0025] Preferably, in the preparation process of the reinforcing layer, the opening step includes: opening and combing the short-cut carbon fiber filaments through a roller carding machine to obtain mixed carbon filaments.

[0026] Preferably, in the opening step of preparing the reinforcing layer, the parameters of the roller carding machine include: 6 to 8 sets of working rollers, a working roller linear speed of 50 to 70 m / min, and a cylinder linear speed of 1100 to 1200 m / min.

[0027] Preferably, in the preparation process of the reinforcing layer, the needle punching step includes: needle punching the loosened mixed carbon wire to obtain an areal density of 150-250 g / m². 2 The reinforced mesh tire.

[0028] Preferably, in the needle-punching step of preparing the reinforcing layer, the needle-punching density is 10-15 needles / cm. 2 .

[0029] Preferably, in the preparation process of the reinforcing layer, the step of applying a phenolic resin liquid with a carbon content of 40-45% includes: spraying the surface of the single piece of the reinforcing layer mesh and then allowing it to stand.

[0030] Preferably, in the step of preparing the reinforcing layer using a phenolic resin liquid with a carbon content of 40-45%, the viscosity of the phenolic resin liquid is <1000 cps; and the material-to-liquid ratio of the spray is 1:(1.4-1.6).

[0031] Preferably, in the step of preparing the reinforcing layer by applying a phenolic resin solution with a carbon content of 40-45%, the settling time is 0.5-2 hours.

[0032] Preferably, in the preparation process of the reinforcing layer, the step of applying phenolic resin powder with a residual carbon content of 55-60% includes: applying phenolic resin liquid to the surface of the reinforcing layer mesh under vibration conditions, and then applying phenolic resin powder with a residual carbon content of 55-60%.

[0033] Preferably, in the step of preparing the reinforcing layer by applying phenolic resin powder with a residual carbon content of 55-60%, the vibration frequency is 13-18 Hz; and the applied powder-to-material ratio is 1:(0.6-0.8).

[0034] Preferably, during the preparation of the reinforcing layer, the number of layers stacked is 4 to 10.

[0035] Preferably, during the preparation of the reinforcing layer, the curing and pressing temperature is 170-180°C, and the compression ratio of the curing and pressing is ≥6.5.

[0036] Preferably, in the preparation process of the composite layer, the step of applying a phenolic resin liquid with a residual carbon content of 46-50% includes: applying the phenolic resin liquid with a residual carbon content of 46-50% to a surface density of 1100-1300 g / m² using a pneumatic spray gun.2 The surface of the soft felt.

[0037] Preferably, during the preparation of the composite layer, the thickness of the soft felt is ≥15mm and the density is ≤0.085g / cm³. 3 The viscosity of the phenolic resin solution is ≥10000 cps; the amount of adhesive applied is 240-260 g / m³. 2 ;

[0038] Preferably, during the preparation of the composite layer, the curing temperature is 210–230°C.

[0039] Preferably, in the preparation process of the carbon-carbon thermal insulation felt matrix, the step of applying a phenolic resin liquid with a residual carbon content of 30-35% includes: applying the phenolic resin liquid with a residual carbon content of 30-35% to a surface density of 800-1100 g / m² using a spray adhesive device. 2 The soft felt has two sides.

[0040] Preferably, during the preparation of the carbon-carbon thermal insulation felt matrix, the thickness of the soft felt is ≥10mm and the density is ≤0.090g / cm³. 3 The viscosity of the phenolic resin solution is ≤400cps; the applied material-to-liquid ratio is 1:(2.4~2.6).

[0041] Preferably, during the preparation of the carbon-carbon thermal insulation felt matrix, the curing temperature is 210–230°C.

[0042] Preferably, in the preparation process of the carbon-carbon thermal insulation felt matrix, the step of applying a phenolic resin liquid with a residual carbon content of 46-50% includes: applying the phenolic resin liquid with a residual carbon content of 46-50% to the surface of the soft felt using a pneumatic spray gun.

[0043] Preferably, in the step of applying a phenolic resin solution with a residual carbon content of 46-50% to prepare the carbon-carbon insulation felt matrix, the viscosity of the phenolic resin solution is ≥10000 cps; and the amount of adhesive applied is 240-260 g / m³. 2 .

[0044] Preferably, during the preparation of the carbon-carbon thermal insulation felt matrix, the number of layers stacked is 5 to 65.

[0045] Preferably, during the preparation of the carbon-carbon thermal insulation felt matrix, the curing and pressing temperature is 210-230°C, and the compression ratio of the curing and pressing is (1.15-1.3):1.

[0046] Preferably, in the preparation process of the composite carbon-carbon insulation felt, the step of applying a phenolic resin liquid with a residual carbon content of 46-50% includes: applying the phenolic resin liquid with a residual carbon content of 46-50% to the surface of the carbon-carbon insulation felt matrix using a pneumatic spray gun.

[0047] Preferably, in the step of applying a phenolic resin solution with a residual carbon content of 46-50% in the preparation of the composite carbon-carbon insulation felt, the viscosity of the phenolic resin solution is ≥10000 cps; and the amount of adhesive applied is 240-260 g / m³. 2 .

[0048] Preferably, during the preparation of the composite carbon-carbon thermal insulation felt, the curing temperature is 210–230°C.

[0049] Preferably, the carbonization process includes:

[0050] A protective gas is introduced into the carbonization furnace. After 3 to 5 hours of this process, the temperature is raised. The corresponding process curve is set, and the total time is 29 to 30 hours to raise the temperature to 940 to 960°C. The temperature is then maintained at 940 to 960°C for 4 to 6 hours. Finally, the temperature is lowered to 60 to 80°C to stop the carbonization process.

[0051] Preferably, the high-temperature treatment procedure includes:

[0052] The high-temperature furnace is evacuated to a vacuum level below -0.1 MPa. A protective gas is introduced, and the corresponding process curve is set. The total time is 48-52 hours to raise the temperature to 2250-2350℃, and then the temperature is held at 2250-2350℃ for 18-22 hours. The high-temperature treatment is then stopped by cooling the temperature down to 60-80℃.

[0053] Secondly, the present invention provides a composite carbon-carbon thermal insulation rigid felt, the composite carbon-carbon thermal insulation rigid felt comprising a reinforcing layer, a buffer layer and a carbon-carbon thermal insulation rigid felt matrix stacked sequentially; and the composite carbon-carbon thermal insulation rigid felt is prepared by the preparation method of the composite carbon-carbon thermal insulation rigid felt described in the first aspect.

[0054] Preferably, the thickness of the reinforcing layer is 1–6.5 mm, the thickness of the buffer layer is 5–15 mm, and the thickness of the carbon-carbon thermal insulation felt substrate is 20–300 mm.

[0055] Preferably, the density of the reinforcing layer is 1.35–1.45 g / cm³. 3 The density of the buffer layer is 0.080–0.085 g / cm³. 3 The density of the carbon-carbon thermal insulation felt matrix is ​​0.15–0.17 g / cm³. 3 .

[0056] Preferably, the porosity of the reinforcing layer is 15-20%, the porosity of the buffer layer is 95-96%, and the porosity of the carbon-carbon thermal insulation felt matrix is ​​90-92%.

[0057] Preferably, the thermal conductivity of the buffer layer is 0.05 to 0.10 W / mk, and the thermal conductivity of the carbon-carbon insulating felt matrix is ​​0.17 to 0.25 W / mk.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] (1) The carbon carbon thermal insulation hard felt of the present invention has a high-density reinforcing layer structure on its surface, which has good impact resistance, bending resistance, erosion resistance and low porosity, greatly enhancing the carbon carbon thermal insulation hard felt's ability to resist high-speed airflow erosion and erosion during use and extending the product's service life.

[0060] (2) The carbon-carbon thermal insulation hard felt of the present invention has a low-density buffer layer between the reinforcing layer and the carbon-carbon thermal insulation hard felt matrix. This structure has high porosity, high specific surface area, high thermal insulation performance and elasticity. The thermal conductivity of this layer is only 0.1W / mk. The low thermal conductivity has good resistance to high temperature impact. During use, it can buffer and deform the difference in linear expansion coefficient between the surface reinforcing layer and the carbon-carbon thermal insulation hard felt matrix caused by high temperature, and reduce the probability of delamination abnormality caused by the difference in linear expansion coefficient during product use.

[0061] (3) The low-density buffer layer of the carbon carbon thermal insulation hard felt of the present invention has a high specific surface area and good adsorption performance for corrosive and reactive gases. It can effectively adsorb corrosive and reactive gases that penetrate into the carbon carbon thermal insulation hard felt matrix through the reinforcing layer during use, thus protecting the carbon carbon thermal insulation hard felt matrix and extending the service life of the product. Attached Figure Description

[0062] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0063] Figure 1 This is a schematic diagram of the structure of the composite carbon-carbon thermal insulation rigid felt described in this invention.

[0064] Among them, 1 is the reinforcing layer, 2 is the buffer layer, and 3 is the carbon-carbon thermal insulation felt substrate. Detailed Implementation

[0065] Unless otherwise defined herein, scientific and process terms used in conjunction with this invention should have the meanings commonly understood by one of ordinary skill in the art. The meaning and scope of terms should be clear; however, in any case of potential ambiguity, the definitions provided herein take precedence over any dictionary or foreign definitions. In this application, unless otherwise stated, the use of "or" means "and / or". Furthermore, the use of the term "comprising" and other forms is non-limiting.

[0066] It should be noted that specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many ways other than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0067] The embodiments and examples of the present invention will be described in detail below. However, those skilled in the art will understand that the following embodiments and examples are for illustrative purposes only and should not be considered as limiting the scope of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Unless otherwise specified, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0068] In a first aspect, the present invention provides a method for preparing a composite carbon-carbon thermal insulation rigid felt, the method comprising:

[0069] Preparation of soft felt: Short-cut carbon fiber filaments are opened and formed into a web to obtain a carbon fiber web; the carbon fiber web is then laid in a Z-shaped reciprocating pattern and reinforced by needle punching to obtain a surface density of 800-1300 g / m². 2 Soft felt;

[0070] Preparation of the reinforcing layer: Short carbon fiber filaments are opened and needle-punched to obtain an areal density of 150-250 g / m². 2 The reinforcing layer mesh is formed by applying a phenolic resin liquid with a carbon content of 40-45% to the surface of a single piece of the reinforcing layer mesh, followed by applying phenolic resin powder with a residual carbon content of 55-60%. The single pieces of mesh after applying the phenolic resin twice are stacked, cured, and pressed to obtain the reinforcing layer.

[0071] Preparation of composite layer: surface density of 1100-1300 g / m² 2 A phenolic resin liquid with a residual carbon content of 46-50% is applied to the surface of the soft felt to cover the reinforcing layer. After curing, a composite layer of buffer layer and reinforcing layer is obtained.

[0072] Preparation of carbon-carbon thermal insulation felt matrix: for single sheet surface density of 800-1100 g / m 2 A phenolic resin liquid with a residual carbon content of 30-35% is applied to both sides of the soft felt. After curing, a phenolic resin liquid with a residual carbon content of 46-50% is applied. The single soft felts with the applied phenolic resin are stacked, cured, and pressed to obtain a carbon-carbon thermal insulation felt matrix.

[0073] Preparation of composite carbon-carbon thermal insulation felt: A phenolic resin liquid with a residual carbon rate of 46-50% is applied to the surface of the carbon-carbon thermal insulation felt matrix, covering the composite layer, and cured to obtain composite carbon-carbon thermal insulation felt;

[0074] Preparation of composite carbon-carbon thermal insulation hard felt: The composite carbon-carbon thermal insulation felt is carbonized and subjected to high temperature treatment to obtain composite carbon-carbon thermal insulation hard felt.

[0075] In this invention, the preparation process of carbon-carbon thermal insulation rigid felt is as follows: carbon fiber short cutting - opening - web formation - composite reinforcement (after reinforcement, it can be cut and prepared) - reinforcing layer pressing - buffer layer shaping - adhesive spraying and curing - lay-up hot pressing - hot pressing composite - carbonization - high temperature - finished product. This preparation method yields a carbon fiber thermal insulation rigid felt that is erosion-resistant, corrosion-resistant, and has a long service life under high temperature and furnace pressure conditions, which is used to improve the insufficient service life of traditional ordinary carbon fiber thermal insulation rigid felt under high temperature and high pressure conditions.

[0076] It is important to note that the key point of this invention lies in a novel carbon-carbon thermal insulation felt product with a composite structure. This product utilizes a high-temperature composite process to add a high-density erosion-resistant reinforcing layer and a low-density, high-surface-area buffer layer to the surface of the traditional carbon-carbon thermal insulation felt. This significantly improves the service life of the carbon-carbon thermal insulation felt under special working conditions such as high temperature, high-speed airflow erosion, and corrosive steam, achieving a comprehensive service life more than six times that of traditional carbon-carbon thermal insulation felt. This novel carbon-carbon thermal insulation felt employs a multi-layered composite structure consisting of a high-density reinforcing layer, a low-density buffer layer, and a carbon-carbon thermal insulation felt matrix. The high-density reinforcing layer is manufactured using precise control over the mass ratio of phenolic resin to the reinforcing mesh, the parameters during the curing and pressing process, and a needle-free composite method for multi-layered reinforcing mesh layering. The low-density buffer layer is manufactured using precise control over the mass ratio of phenolic resin to the soft felt and the parameters during the curing and pressing process. Furthermore, this invention further improves the service life of carbon-carbon thermal insulation felt under high temperature and high pressure conditions by using a step-by-step composite processing method and controlling the composite process parameters of the carbon-carbon thermal insulation felt matrix, high-density reinforcing layer, and low-density buffer layer.

[0077] As an optional implementation, in the preparation process of the soft felt, the chopped carbon fiber filaments are selected from mixed chopped carbon filaments with a length of 40 to 120 mm (e.g., 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 110 mm, 120 mm, etc.).

[0078] As an optional implementation, in the mixed chopped carbon filaments: the proportion of chopped carbon filaments with a length <60mm is <50wt% (e.g., it can be 45wt%, 40wt%, 35wt%, 30wt%, 25wt%, 20wt%, 15wt%, 10wt%, 5wt%, 1wt%, 0wt%, etc.), and the proportion of chopped carbon filaments with a length >100mm is ≥10wt% (e.g., it can be 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt%, etc.).

[0079] In a preferred embodiment, during the preparation of the soft felt, the chopped carbon fiber filaments are selected from mixed chopped carbon filaments with a length of 40 to 120 mm.

[0080] As an optional implementation, in the preparation process of the soft felt, the opening step includes: stirring the chopped carbon fiber filaments to obtain a preliminary mixed carbon filament; and opening the preliminary mixed carbon filament through a multi-roller opening machine to obtain a mixed carbon filament.

[0081] It should be noted that the above-mentioned opening process specifically includes: placing short carbon filaments of different lengths into a mixing container, and achieving preliminary mixing of the short carbon filaments of different lengths through mechanical stirring. The preliminarily mixed carbon filaments are then poured onto the drive curtain of the opening machine, passed through a metal impurity remover, and fed into a multi-roller opening machine to achieve the opening and mixing of the short carbon filaments.

[0082] As an optional implementation, in the opening step of preparing the soft felt, the stirring speed is 65-75 rpm (e.g., 65 rpm, 66 rpm, 68 rpm, 70 rpm, 72 rpm, 74 rpm, 75 rpm, etc.), and the stirring time is 3-5 min (e.g., 3 min, 3.5 min, 4 min, 4.5 min, 5 min, etc.); the parameters of the multi-roller opening machine include: 4-8 pairs of opening rollers (e.g., 4 pairs, 6 pairs, 8 pairs, etc.), the frequency of the opening rollers is 10-20 Hz (e.g., 10 Hz, 12 Hz, 14 Hz, 16 Hz, 18 Hz, 20 Hz, etc.), and the frequency of the cylinder is 40-50 Hz (e.g., 40 Hz, 42 Hz, 44 Hz, 46 Hz, 48 Hz, 50 Hz, etc.).

[0083] It should be noted that in the opening step of preparing the soft felt, the present invention controls the mixing speed and time to achieve preliminary mixing of short carbon filaments of different lengths, which facilitates subsequent opening. Furthermore, by setting the number of logarithms of the multi-roller opening rollers, excessive tensile force on the carbon fibers can be better avoided, reducing damage to the carbon fibers. It can also make the tension of the carbon fibers more uniform during the opening process, better avoiding breakage problems caused by uneven tension. At the same time, the setting of the frequency of the opening rollers and the frequency of the cylinder in the opening machine results in a relatively stable force distribution during the opening process, which can also better maintain the integrity and length of the fibers.

[0084] As an optional implementation, in the preparation process of the soft felt, the web-forming step includes: sending the loosened mixed carbon filaments into a cotton box through a high-speed airflow to form fiber clusters, combing them through a high-speed cylinder to form a fiber web, and peeling them off from the high-speed cylinder through negative pressure adsorption to obtain a carbon fiber web.

[0085] It should be noted that the above-mentioned web formation specifically includes: after the fibers are opened by a multi-roller opener, they are fed into a cotton box by a high-speed airflow. The opened fiber clumps are lifted upwards by a conveyor curtain to a leveling roller and a drop roller. After being homogenized and metered by the leveling roller, the fiber clumps are peeled off by the drop roller and transferred to a vibrating plate. The vibrating plate causes the fiber clumps to fall and be evenly stacked on a conveyor curtain to form a continuous fiber clump. After being accurately metered by a precision metering device, the continuous fiber clumps are fed into a high-speed cylinder by a feed roller. The cylinder combs the fiber clumps at high speed to form a fiber web. The fiber web is adsorbed by a breathable curtain with negative pressure and peeled off from the high-speed cylinder. Subsequently, the carbon fiber web is sent to a reciprocating web-laying curtain via a conveyor curtain for reciprocating stacking.

[0086] As an optional implementation, in the web-forming step of preparing the soft felt, the rotation speed of the high-speed cylinder is 1200-1300 rpm (e.g., 1200 rpm, 1220 rpm, 1240 rpm, 1250 rpm, 1260 rpm, 1280 rpm, 1300 rpm, etc.); the negative pressure adsorption is provided by fans on both sides, and the frequency of the fans is 30-40 Hz (e.g., 30 Hz, 32 Hz, 34 Hz, 35 Hz, 36 Hz, 38 Hz, 40 Hz, etc.).

[0087] It should be noted that during the above-mentioned web formation process, the fiber clusters are combed by a high-speed cylinder to form a fiber web. The fiber web is then adsorbed by a breathable curtain with negative pressure and more completely stripped from the high-speed cylinder, forming a highly disordered, isotropic, continuous carbon fiber web with a certain strength.

[0088] As an optional implementation, during the preparation of the soft felt, the carbon fiber mesh is laid in a zigzag pattern and then reinforced by needle punching to obtain a surface density of 800–1300 g / m².2 (For example, it could be 800g / m 2 850g / m 2 900g / m 2 950g / m 2 1000g / m 2 1050g / m 2 1100g / m 2 1150g / m 2 1200g / m 2 1250g / m 2 1300g / m 2 Soft felt (etc.).

[0089] It should be noted that the carbon fiber mesh is sequentially passed through the feeding curtain, annular curtain, reciprocating curtain, and output clamping roller of the reciprocating web laying machine, and then repeatedly laid in a "Z" shape according to the parameter settings. By setting the number of web layers of the web laying machine, the required areal density of the product design is achieved; that is, the areal density of the soft felt is adjusted by the number of web layers. Furthermore, multiple pre-needling machines with needle plate arrangements such as top-needling, bottom-needling, and top-bottom-needling are used to repeatedly needle-punch and reinforce the completed fiber web, ultimately obtaining an areal density of 800–1300 g / m². 2 The soft felt is a carbon-carbon thermal insulation hard felt blank with different surface densities.

[0090] As an optional implementation, during the preparation of the soft felt, when the areal density of the soft felt is 1100-1300 g / m³ 2 For example, it could be 1100g / m 2 1150g / m 2 1200g / m 2 1250g / m 2 1300g / m 2 The number of repetitive layers is 22 to 26, for example, 22, 23, 24, 25, or 26 layers, and the density of the needle reinforcement is 15 to 25 needles / cm. 2 For example, it could be 15 stitches / cm 2 16 stitches / cm 2 17 stitches / cm 2 18 stitches / cm 2 19 stitches / cm 2 20 stitches / cm 2 21 stitches / cm 2 22 stitches / cm 2 23 stitches / cm 2 24 stitches / cm 2 25 stitches / cm 2 wait.

[0091] As an optional implementation, during the preparation of the soft felt, when the areal density of the soft felt is 800-1100 g / m³ 2 For example, it could be 800g / m 2 850g / m 2 900g / m 2 950g / m 2 1000g / m 2 1050g / m 2 1080g / m 2 The number of repetitive layers is 16 to 22, for example, 16, 17, 18, 19, 20, 21, or 22 layers, and the density of the needle reinforcement is 15 to 25 needles / cm. 2 For example, it could be 15 stitches / cm 2 16 stitches / cm 2 17 stitches / cm 2 18 stitches / cm 2 19 stitches / cm 2 20 stitches / cm 2 21 stitches / cm 2 22 stitches / cm 2 23 stitches / cm 2 24 stitches / cm 2 25 stitches / cm 2 wait.

[0092] As an optional implementation, during the preparation of the soft felt, the areal density obtained by needle punching reinforcement is 800–1300 g / m². 2 The soft felt can also be prepared by cutting, that is, the size of the reinforced soft felt is cut according to the size of the product blank, and the number of soft felt sheets required for carbon carbon insulation felt is prepared with weight and thickness as the target.

[0093] As an optional implementation, during the preparation of the reinforcing layer, the chopped carbon fiber filaments are selected from mixed chopped carbon filaments with a length of 40 to 120 mm (e.g., 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 110 mm, 120 mm, etc.).

[0094] As an optional implementation, in the preparation process of the reinforcing layer, the opening step includes: opening and combing the short-cut carbon fiber filaments through a roller carding machine to obtain mixed carbon filaments.

[0095] As an optional implementation, in the opening step of preparing the reinforcing layer, the parameters of the roller carding machine include: 6 to 8 sets of working rollers (e.g., 6, 7, or 8 sets), a working roller linear speed of 50 to 70 m / min (e.g., 50 m / min, 52 m / min, 54 m / min, 55 m / min, 56 m / min, 58 m / min, 60 m / min, 62 m / min, 64 m / min, 66 m / min, 68 m / min, 70 m / min, etc.), and a cylinder linear speed of 1100 to 1200 m / min (e.g., 1100 m / min, 1120 m / min, 1140 m / min, 1150 m / min, 1160 m / min, 1180 m / min, 1200 m / min, etc.).

[0096] As an optional implementation, in the preparation process of the reinforcing layer, the needle punching step includes: needle punching the loosened mixed carbon wire to obtain a surface density of 150-250 g / m². 2 (For example, it could be 150g / m 2 160g / m 2 170g / m 2 180g / m 2 190g / m 2 200g / m 2 210g / m 2 220g / m 2 130g / m 2 240g / m 2 250g / m 2 (etc.) reinforced mesh tires.

[0097] As an optional implementation, in the needle-punching step of preparing the reinforcing layer, the needle-punching density is 10-15 needles / cm. 2 (For example, it could be 10 stitches / cm) 2 11 stitches / cm 2 12 stitches / cm 2 13 stitches / cm 2 14 stitches / cm 2 15 stitches / cm 2 wait).

[0098] As an optional implementation, after the needle punching step of preparing the reinforcing layer, the completed reinforcing layer mesh can be cut into several pieces according to the preset reinforcing layer product density to complete the preparation of the reinforcing layer mesh.

[0099] As an optional implementation, in the preparation process of the reinforcing layer, the step of applying a phenolic resin liquid with a carbon content of 40-45% (e.g., 40%, 41%, 42%, 43%, 44%, 45%, etc.) includes: spraying the surface of the single piece of the reinforcing layer mesh and then letting it stand.

[0100] As an optional implementation, in the step of preparing the phenolic resin solution with an application carbon ratio of 40-45% (e.g., 40%, 41%, 42%, 43%, 44%, 45%, etc.), the viscosity of the phenolic resin solution is <1000 cps (e.g., 990 cps, 980 cps, 960 cps, 950 cps, 940 cps, 920 cps, 900 cps, 850 cps, 800 cps, 700 cps, 600 cps, 500 cps, etc.); the material-to-liquid ratio of the spray is 1:(1.4-1.6) (e.g., 1:1.4, 1:1.45, 1:1.5, 1:1.55, 1:1.6, etc.). [The phenolic resin solution with an application carbon ratio of 40-45% is referred to as phenolic resin solution one.]

[0101] As an optional implementation, in the step of preparing the reinforcing layer with a phenolic resin solution having an application carbon ratio of 40-45%, the standing time is 0.5-2 hours (e.g., 0.5 hours, 0.6 hours, 0.7 hours, 0.8 hours, 0.9 hours, 1 hour, 1.2 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.8 hours, 2 hours, etc.).

[0102] As an optional embodiment, in the preparation process of the reinforcing layer, the step of applying phenolic resin powder with a residual carbon content of 55-60% includes: under vibration conditions, applying phenolic resin liquid to one side of the reinforcing layer mesh, and then applying phenolic resin powder with a residual carbon content of 55-60% (e.g., 55%, 56%, 57%, 58%, 59%, 60%, etc.). [The aforementioned phenolic resin powder with a carbon content of 55-60% is referred to as phenolic resin powder two.]

[0103] As an optional implementation, in the step of preparing the reinforcing layer by applying phenolic resin powder with a residual carbon content of 55-60%, the vibration frequency is 13-18 Hz, for example, 13 Hz, 14 Hz, 15 Hz, 16 Hz, 17 Hz, 18 Hz, etc.; the applied powder-to-material ratio is 1:(0.6-0.8) (for example, 1:0.6, 1:0.65, 1:0.7, 1:0.75, 1:0.8, etc.).

[0104] As an optional implementation, the number of layers stacked during the preparation of the reinforcing layer is 4 to 10.

[0105] As an optional implementation, during the preparation of the reinforcing layer, the curing and pressing temperature is 170-180℃ (e.g., 170℃, 172℃, 174℃, 175℃, 176℃, 178℃, 180℃, etc.), and the compression ratio of the curing and pressing is ≥6.5 (e.g., 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, etc.).

[0106] As an optional implementation, the method for preparing the reinforcing layer includes the following steps:

[0107] Using a peristaltic pump and a resin spraying device with a gear pump, the surface of the single-layer reinforced mesh is sprayed with a phenolic resin liquid with a viscosity of <1000cps and a residual carbon content of 40-45%. After spraying, the mesh is left to stand in a container with polytetrafluoroethylene (PTFE). After standing, the container is transferred to a vibrating screen, and a second layer of phenolic resin powder with a residual carbon content of 55-60% is applied to the surface of the mesh after the first layer of phenolic resin liquid has been sprayed. After the two applications of phenolic resin are completed, the mesh is stacked sequentially, covered with a high-temperature resistant cloth with a PTFE surface, and then cured and pressed.

[0108] It should be noted that, in this invention, the surface of a single-layer reinforcing mesh is sprayed with a phenolic resin liquid (1) with a residual carbon content of 40-45%, and then, with the assistance of a vibrating screen, a phenolic resin powder (2) with a residual carbon content of 55-60% is applied to the surface of the mesh after the phenolic resin liquid (1) has been sprayed. By controlling the residual carbon content of these two phenolic resins, and by stacking and curing the mesh, a high-density reinforcing layer structure is obtained. This reinforcing layer has good impact resistance, bending resistance, erosion resistance, and low porosity, which greatly enhances the ability of carbon carbon insulation felt to resist high-speed airflow erosion and corrosion during use, and extends the product's service life.

[0109] As an optional embodiment, in the preparation process of the composite layer, the step of applying a phenolic resin liquid with a residual carbon content of 46-50% (e.g., 46%, 47%, 48%, 49%, 50%, etc.) includes: applying the phenolic resin liquid with a residual carbon content of 46-50% to a surface density of 1100-1300 g / m² using a pneumatic spray gun. 2 (For example, it could be 1100g / m 2 1120g / m 2 1140g / m 2 1150g / m 2 1160g / m 2 1180g / m 2 1200g / m 2 1220g / m 2 1240g / m 2 1250g / m2 1260g / m 2 1280g / m 2 1300g / m 2 The surface of the soft felt (etc.). [The above-mentioned phenolic resin solution with a residual carbon rate of 46-50% is referred to as phenolic resin solution three.]

[0110] As an optional implementation, during the preparation of the composite layer, the thickness of the soft felt is ≥15mm (e.g., it can be 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, etc.), and the density is ≤0.085g / cm³. 3 (For example, it could be 0.085 g / cm³) 3 0.084 g / cm 3 0.083g / cm 3 0.082g / cm 3 0.081g / cm 3 0.080g / cm 3 (etc.); the viscosity of the phenolic resin liquid is ≥10000 cps (e.g., it can be 10000 cps, 11000 cps, 12000 cps, 13000 cps, 14000 cps, 15000 cps, 16000 cps, 17000 cps, 18000 cps, 19000 cps, 20000 cps, etc.); the amount of adhesive applied is 240~260g / m³. 2 (For example, it could be 240g / m 2 242g / m 2 244g / m 2 245g / m 2 246g / m 2 248g / m 2 250g / m 2 252g / m 2 254g / m 2 255g / m 2 256g / m 2 258g / m 2 260g / m 2 wait).

[0111] As an optional implementation, during the preparation of the composite layer, the curing temperature is 210-230℃ (e.g., 210℃, 212℃, 214℃, 216℃, 218℃, 220℃, 222℃, 224℃, 225℃, 226℃, 228℃, 230℃, etc.).

[0112] As an optional implementation, the method for preparing the composite layer of the buffer layer and the reinforcing layer includes the following steps:

[0113] Select a surface density of 1100–1300 g / m³ 2 The soft felt is coated with a phenolic resin liquid of ≥10000cps and 46-50% carbon residue using a pneumatic spray gun. The phenolic resin liquid is applied only to the upper surface of the soft felt (the side closer to the reinforcing layer and the side farther from the carbon-carbon thermal insulation hard felt substrate). After the phenolic resin is applied, the cured and pressed reinforcing layer and the high-temperature resistant cloth with polytetrafluoroethylene are placed on top. The mixture is then cured at high temperature (without compression ratio) using a press to complete the composite shaping of the buffer layer and the reinforcing layer, resulting in the composite layer of the buffer layer and the reinforcing layer.

[0114] It should be noted that the present invention achieves a surface density of 1100–1300 g / m³ through the above process. 2 A phenolic resin liquid with a residual carbon content of 46-50% is applied to the soft felt and cured at high temperature without compression ratio to form a buffer layer between the reinforcing layer and the matrix. This low-density buffer layer possesses high porosity, high specific surface area, high thermal insulation performance, and elasticity. Its thermal conductivity is only about 0.1 W / mK, providing excellent resistance to high-temperature impact. During use, it can buffer and mitigate the difference in linear expansion coefficients between the surface reinforcing layer and the carbon-carbon thermal insulation felt matrix caused by high temperatures, reducing the probability of delamination caused by differences in linear expansion coefficients during product use. Furthermore, due to its high specific surface area, this low-density buffer layer has excellent adsorption properties for corrosive and reactive gases, effectively adsorbing corrosive and reactive gases that permeate into the carbon-carbon thermal insulation felt matrix through the reinforcing layer during use, thus protecting the carbon-carbon thermal insulation felt matrix and extending the product's service life.

[0115] As an optional embodiment, in the preparation process of the carbon-carbon thermal insulation felt matrix, the step of applying a phenolic resin liquid with a residual carbon content of 30-35% (e.g., 30%, 31%, 32%, 33%, 34%, 35%, etc.) includes: applying the phenolic resin liquid with a residual carbon content of 30-35% to a surface density of 800-1100 g / m² using a spraying device. 2 (For example, it could be 800g / m 2 820g / m 2 840g / m 2 850g / m 2 860g / m 2 880g / m 2 900g / m 2 920g / m 2 940g / m 2 950g / m2 960g / m 2 980g / m 2 1000g / m 2 1020g / m 2 1040g / m 2 1060g / m 2 1080g / m 2 1100g / m 2 The soft felt (etc.) has two sides. [The above-mentioned phenolic resin solution with a residual carbon content of 30-35% is referred to as phenolic resin solution four.]

[0116] As an optional implementation, during the preparation of the carbon-carbon thermal insulation felt matrix, the thickness of the soft felt is ≥10mm (e.g., 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, etc.), and the density is ≤0.090g / cm³. 3 (For example, it could be 0.090 g / cm³) 3 0.089g / cm 3 0.088g / cm 3 0.087g / cm 3 0.086g / cm 3 (etc.); the viscosity of the phenolic resin liquid is ≤400cps (e.g., it can be 400cps, 390cps, 380cps, 360cps, 350cps, 340cps, 320cps, 300cps, 280cps, 260cps, 250cps, 240cps, 220cps, 200cps, 150cps, 100cps, 50cps, etc.); the applied material-to-liquid ratio is 1:(2.4~2.6) (e.g., it can be 1:2.4, 1:2.45, 1:2.5, 1:2.55, 1:2.6, etc.).

[0117] As an optional implementation, during the preparation of the carbon-carbon thermal insulation felt matrix, the curing temperature is 210 to 230°C, for example, 210°C, 212°C, 214°C, 215°C, 216°C, 218°C, 220°C, 222°C, 224°C, 226°C, 228°C, 230°C, etc.

[0118] As an optional implementation, in the preparation process of the carbon-carbon thermal insulation felt matrix, the step of applying a phenolic resin liquid with a residual carbon content of 46-50% (e.g., 46%, 47%, 48%, 49%, 50%, etc.) includes: applying the phenolic resin liquid with a residual carbon content of 46-50% to the surface of the soft felt using a pneumatic spray gun.

[0119] As an optional implementation, in the step of applying a phenolic resin liquid with a residual carbon content of 46-50% to prepare the carbon-carbon insulation felt matrix, the viscosity of the phenolic resin liquid is ≥10000 cps (e.g., it can be 10000 cps, 11000 cps, 12000 cps, 13000 cps, 14000 cps, 15000 cps, 16000 cps, 17000 cps, 18000 cps, 19000 cps, 20000 cps, etc.); the amount of adhesive applied is 240-260 g / m³. 2 (For example, it could be 240g / m 2 242g / m 2 244g / m 2 245g / m 2 246g / m 2 248g / m 2 250g / m 2 252g / m 2 254g / m 2 255g / m 2 256g / m 2 258g / m 2 260g / m 2 wait).

[0120] As an optional implementation, during the preparation of the carbon-carbon thermal insulation felt matrix, the number of layers stacked is 5 to 65, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, etc.

[0121] As an optional implementation, during the preparation of the carbon-carbon thermal insulation felt matrix, the curing and pressing temperature is 210-230℃, for example, it can be 210℃, 212℃, 214℃, 215℃, 216℃, 218℃, 220℃, 222℃, 224℃, 226℃, 228℃, 230℃, etc., and the compression ratio of the curing and pressing is (1.15-1.3):1, for example, it can be 1.15:1, 1.16:1, 1.18:1, 1.2:1, 1.22:1, 1.24:1, 1.26:1, 1.28:1, 1.3:1, etc.

[0122] As an optional implementation, the method for preparing the carbon-carbon thermal insulation felt matrix includes the following steps:

[0123] Select a surface density of 800–1100 g / m³ 2The soft felt is treated with adhesive by spraying it into an adhesive spraying device. The device is used to spray phenolic resin liquid with a residual carbon content of 30-35% onto both sides. After the adhesive spraying is completed, the soft felt is dried in a hot air penetrating oven equipped with a radiant pre-drying device. After the soft felt is dried, phenolic resin liquid with a residual carbon content of 46-50% is applied to the surface of each soft felt using a pneumatic spray paint. After the adhesive spraying is completed, the soft felts are laid up in sequence and transferred to a press as a whole for hot pressing and curing to obtain the carbon-carbon thermal insulation felt matrix.

[0124] As an optional implementation, in the preparation process of the composite carbon-carbon insulation felt, the step of applying a phenolic resin liquid with a residual carbon content of 46-50% (e.g., 46%, 47%, 48%, 49%, 50%, etc.) includes: applying the phenolic resin liquid with a residual carbon content of 46-50% to the surface of the carbon-carbon insulation felt matrix using a pneumatic spray gun. [The aforementioned phenolic resin liquid with a residual carbon content of 46-50% is referred to as phenolic resin liquid three.]

[0125] As an optional implementation, in the step of applying a phenolic resin solution with a residual carbon rate of 46-50% in the preparation of the composite carbon-carbon insulation felt, the viscosity of the phenolic resin solution is ≥10000 cps (e.g., it can be 10000 cps, 11000 cps, 12000 cps, 13000 cps, 14000 cps, 15000 cps, 16000 cps, 17000 cps, 18000 cps, 19000 cps, 20000 cps, etc.); the amount of adhesive applied is 240-260 g / m². 2 (For example, it could be 240g / m 2 242g / m 2 244g / m 2 245g / m 2 246g / m 2 248g / m 2 250g / m 2 252g / m 2 254g / m 2 255g / m 2 256g / m 2 258g / m 2 260g / m 2 wait).

[0126] As an optional implementation, in the preparation process of the composite carbon-carbon insulation felt, the curing temperature is 210-230℃ (for example, it can be 210℃, 212℃, 212℃, 214℃, 216℃, 218℃, 220℃, 222℃, 224℃, 225℃, 226℃, 228℃, 230℃, etc.).

[0127] As an optional implementation, the preparation method of the composite carbon-carbon thermal insulation felt includes the following steps:

[0128] A phenolic resin liquid with a residual carbon content of 46-50% is applied again to the upper surface of the carbon-carbon insulation felt substrate. After the adhesive is sprayed, the lower surface of the buffer layer of the composite layer of buffer layer and reinforcing layer is bonded to the upper surface of the substrate layer. After bonding, a high-temperature resistant cloth with polytetrafluoroethylene is placed on top, and a press is used for high-temperature curing (without compression ratio) to complete the hot-pressing composite of buffer layer, reinforcing layer and carbon-carbon insulation felt substrate, thus obtaining the composite carbon-carbon insulation felt.

[0129] As an optional implementation, the carbonization process includes:

[0130] A protective gas is introduced into the carbonization furnace for 3–5 hours (e.g., 3h, 3.5h, 4h, 4.5h, 5h, etc.). The temperature is then raised to 940–960℃ (e.g., 940℃, 945℃, 950℃, 955℃, 960℃, etc.), and then held at 940–960℃ for 4–6 hours (e.g., 4h, 4.5h, 5h, 5.5h, 6h, etc.). Finally, the temperature is lowered to 60–80℃ (e.g., 60℃, 65℃, 70℃, 75℃, 80℃, etc.) to stop carbonization.

[0131] It should be noted that the curing felt is placed in a carbonization furnace for carbonization treatment, so that the phenolic resin in the curing felt is carbonized in a high-temperature environment. After carbonization treatment, the curing felt becomes carbon felt.

[0132] Preferably, the high-temperature treatment procedure includes:

[0133] The high-temperature furnace is evacuated to a vacuum level below -0.1 MPa. A protective gas is introduced, and a corresponding process curve is set. The total time is 48–52 hours (e.g., 48h, 49h, 50h, 51h, 52h, etc.). The temperature is raised to 2250–2350℃ (e.g., 2250℃, 2260℃, 2280℃, 2300℃, 2320℃, 2340℃, 2350℃, etc.). Then, it is held at 2250–2350℃ for 18–22 hours (e.g., 18h, 19h, 20h, 21h, 22h, etc.). Subsequently, the temperature is lowered to 60–80℃ (e.g., 60℃, 62℃, 64℃, 66℃, 68℃, 70℃, 72℃, 74℃, 76℃, 78℃, 80℃, etc.) and the high-temperature treatment is stopped.

[0134] Secondly, the present invention provides a composite carbon-carbon thermal insulation rigid felt, such as Figure 1 As shown, the composite carbon-carbon thermal insulation rigid felt includes a reinforcing layer 1, a buffer layer 2, and a carbon-carbon thermal insulation rigid felt matrix 3 stacked sequentially; and the composite carbon-carbon thermal insulation rigid felt is prepared by the preparation method of the composite carbon-carbon thermal insulation rigid felt described in the first aspect.

[0135] As an optional implementation, the thickness of the reinforcing layer is 1–6.5 mm, for example, it can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, etc.; the thickness of the buffer layer is 5–15 mm, for example, it can be 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, etc.; and the thickness of the carbon-carbon thermal insulation felt substrate is 20 mm. ~300mm, for example, it can be 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, 210mm, 220mm, 230mm, 240mm, 250mm, 260mm, 270mm, 280mm, 290mm, 30mm, etc.

[0136] As an optional implementation, the density of the reinforcing layer is 1.35–1.45 g / cm³. 3 For example, it could be 1.35 g / cm³ 3 1.36 g / cm 3 1.37g / cm 3 1.38g / cm 3 1.39 g / cm 3 1.40g / cm 3 1.41 g / cm 3 1.42g / cm 3 1.43 g / cm 3 1.44 g / cm 3 1.45g / cm 3 The density of the buffer layer is 0.080–0.085 g / cm³. 3 For example, it could be 0.080 g / cm³. 3 0.081g / cm 3 0.082g / cm 3 0.083g / cm 3 0.084 g / cm 3 0.085g / cm 3The density of the carbon-carbon thermal insulation felt matrix is ​​0.15–0.17 g / cm³. 3 For example, it could be 0.150 g / cm³. 3 0.152g / cm 3 0.154g / cm 3 0.156 g / cm 3 0.158g / cm 3 0.160g / cm 3 0.162 g / cm 3 0.164 g / cm 3 0.166 g / cm 3 0.168g / cm 3 0.170g / cm 3 wait.

[0137] As an optional implementation, the porosity of the reinforcing layer is 15-20%, for example, it can be 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, 20%, etc.; the porosity of the buffer layer is 95-96%, for example, it can be 95%, 95.1%, 95.2%, 95.3%, 95.4%, 95.5%, 95.6%, 95.7%, 95.8%, 95.9%, 96%, etc.; and the porosity of the carbon-carbon thermal insulation felt matrix is ​​90-92%, for example, it can be 90%, 90.2%, 90.4%, 90.6%, 90.8%, 91%, 91.2%, 91.4%, 91.6%, 91.8%, 92%, etc.

[0138] As an optional implementation, the thermal conductivity of the reinforcing layer is 0.05 to 0.10 W / mk, for example, 0.05 W / mk, 0.06 W / mk, 0.07 W / mk, 0.08 W / mk, 0.09 W / mk, 0.1 W / mk, etc., and the thermal conductivity of the carbon-carbon thermal insulation felt matrix is ​​0.17 to 0.25 W / mk, for example, 0.17 W / mk, 0.18 W / mk, 0.19 W / mk, 0.20 W / mk, 0.21 W / mk, 0.22 W / mk, 0.23 W / mk, 0.24 W / mk, 0.25 W / mk, etc.

[0139] The present invention will be further illustrated below with specific embodiments and comparative examples. However, it should be understood that these embodiments are merely for the purpose of more detailed illustration and should not be construed as limiting the present invention in any way.

[0140] Example 1

[0141] This embodiment provides a method for preparing a composite carbon-carbon thermal insulation rigid felt, the method comprising the following steps:

[0142] (A) Preparation of soft felt

[0143] Opening: Use mixed short carbon wires with a length of 60-70mm; put the mixed short carbon wires of different lengths into a mixing container and achieve preliminary mixing of short carbon wires of different lengths by mechanical stirring (70rpm, 4min); pour the mixed short carbon wires that have completed the preliminary mixing onto the drive curtain of the opening machine, pass through a metal impurity remover, and feed into a multi-roller opening machine to achieve opening and mixing of short carbon wires (6 pairs of opening rollers, opening roller parameters set to 15Hz, cylinder speed set to 47Hz);

[0144] Web Formation: After the fibers are opened by the multi-roller opener, they are sent into the cotton box by high-speed airflow. The opened fiber clumps are lifted upward by the conveying nail curtain to the leveling roller and the drop roller. After being uniformized and metered by the leveling roller, the fiber clumps are stripped by the drop roller and transferred to the vibrating plate. The vibration of the vibrating plate causes the fiber clumps to fall and be evenly stacked on the conveyor curtain to form a continuous fiber clump. After being metered by the precise metering device, the continuous fiber clumps are sent into the high-speed cylinder by the feed roller (the cylinder speed is set to 1250 rpm). The cylinder combs the fiber clumps at high speed to form a fiber web. The fiber web is adsorbed by the air curtain with negative pressure and stripped from the high-speed cylinder to form a highly disordered, isotropic, continuous fiber web with a certain strength.

[0145] Composite reinforcement: The carbon fiber mesh is fed into the reciprocating web laying curtain through the conveyor curtain. The carbon fiber mesh passes through the feeding curtain, the ring curtain, the reciprocating curtain, and the output clamping roller of the reciprocating web laying machine in sequence. It is then laid in a Z-shaped reciprocating manner according to the parameter setting value, and then needle-punched for reinforcement and cut to obtain soft felt.

[0146] The Z-shaped repetitive layering was set to 18 layers, and the needle reinforcement density was 18 needles / cm. 2 A surface density of 900 g / m³ can be obtained. 2 Soft felt;

[0147] The Z-shaped reciprocating layering was set to 24 layers, and the needle reinforcement density was 22 needles / cm. 2 A surface density of 1200 g / m³ can be obtained. 2 Soft felt.

[0148] (B) Preparation of the reinforcing layer

[0149] Preparation of the reinforced layer mesh: Mixed short-cut carbon wires with a length of 60-70 mm are placed in a roller carding machine for opening and carding (cylinder speed set to linear speed of 1150 m / min, work roll linear speed of 60 m / min, number of work rolls: 7 sets), and needle punching (needle punching density of 12 needles / cm).2 The needles are inserted upwards, perpendicular to the fiber web, to form a reinforcing mesh layer. The surface density of this mesh layer is 200 g / m². 2 ;

[0150] Pressing of the reinforcing layer: Using a peristaltic pump and a resin spraying device with a gear pump, the surface of the single-layer reinforcing mesh is sprayed with phenolic resin liquid one with a viscosity of 800 cps and a residual carbon rate of 43%, at a spraying mass ratio of 1:1.5. After spraying, it is left to stand in a container with polytetrafluoroethylene for 1 hour. After standing, the entire container is transferred to a vibrating screen (vibration frequency of 15 Hz), and phenolic resin powder two with a residual carbon rate of 57% is applied to the surface of the mesh after spraying phenolic resin liquid one, at a mass ratio of 1:0.7. After two applications of phenolic resin, the mesh is stacked sequentially, covered with a high-temperature resistant cloth with a polytetrafluoroethylene surface, and cured and pressed at a pressing temperature of 175℃ and a compression ratio of 6.5:1.

[0151] With 5 layers of mesh fabric stacked together, a single sheet thickness of 1.5 mm and a surface density of 1000 ± 50 g / m³ can be obtained. 2 The reinforcing layer.

[0152] (C) Preparation of composite layer containing buffer layer and reinforcing layer

[0153] The single sheet obtained in step (A) has a thickness of 15 mm and an areal density of 1200 g / m³. 2 Its density is 0.085 g / cm³. 3 The soft felt was coated with a phenolic resin solution with a viscosity of 12000 cps and a residual carbon rate of 47% using a pneumatic spray gun, with a spraying amount of 250 g / m². 2 Resin is applied only to the upper surface of the soft felt; after the surface resin is applied, the cured and pressed reinforcing layer and the high-temperature resistant cloth with polytetrafluoroethylene are placed on top, and high-temperature curing is performed using a press at a curing temperature of 220°C with no compression ratio, thus completing the composite shaping of the buffer layer and the reinforcing layer.

[0154] (D) Preparation of carbon-carbon thermal insulation felt matrix

[0155] Spray adhesive curing: Select a single sheet with a thickness of 10 mm and an areal density of 900 g / m³ obtained in step (A). 2 Its density is 0.090 g / cm³. 3 The soft felt is sprayed with adhesive. The soft felt is pushed into the adhesive spraying device. The total adhesive spraying ratio is soft felt to water-soluble phenolic resin liquid four = 1:2.5. The viscosity of the water-soluble phenolic resin liquid four is 300cps and the resin residual carbon content is 34%. Double-sided adhesive spraying is performed. After the adhesive spraying is completed, the soft felt is dried in a hot air (temperature of 120℃) penetrating oven with a radiant pre-drying device.

[0156] Lamination and Hot Pressing: After the soft felt is dried, a phenolic resin liquid with a viscosity of 12000 cps and a residual carbon rate of 47% is applied to the surface of each soft felt using pneumatic spraying, with a spraying amount of 250 g / m². 2 After applying phenolic resin liquid with a viscosity of 12000cps and a residual carbon rate of 47% in three spray applications, the soft felt is laid up in sequence (10 layers) and transferred as a whole to the press for hot pressing and curing. The curing temperature is 220℃ and the compression ratio is 1.2:1 to make carbon carbon insulation felt matrix.

[0157] (E) Preparation of composite carbon-carbon thermal insulation felt

[0158] Apply a third coat of phenolic resin solution with a viscosity of 12000 cps and a residual carbon content of 47% at a rate of 250 g / m² to the surface of the completed carbon-carbon insulation felt substrate. 2 After the adhesive is applied, the soft felt surface of the buffer layer and reinforcing layer composite is bonded to the upper surface of the carbon-carbon insulation felt. After the buffer layer and reinforcing layer composite is bonded to the carbon-carbon insulation felt substrate, a high-temperature resistant cloth with polytetrafluoroethylene is placed on top, and a press is used for high-temperature curing at 220°C with no compression ratio. This completes the hot-pressing bonding of the buffer layer and reinforcing layer composite with the carbon-carbon insulation felt substrate, resulting in the composite carbon-carbon insulation felt.

[0159] (F) Preparation of composite carbon-carbon thermal insulation felt

[0160] Carbonization treatment: 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; nitrogen is introduced into the carbonization furnace, and after the nitrogen is introduced for 4 hours, the temperature is raised. The corresponding process curve is set, and the total time is 29.5 hours to raise the temperature to 950℃, hold the temperature for 5 hours, and then cool down to 70℃ to obtain carbon felt.

[0161] High-temperature treatment: The carbon felt is placed in a high-temperature furnace and treated at 2300℃; the furnace is evacuated to a vacuum level of -0.1 MPa and argon gas is introduced. The corresponding process curve is set, and the total time is 50 hours. The temperature is raised to 2300℃ and held for 20 hours. Then the temperature is lowered to 70℃. The production of the carbon-carbon thermal insulation hard felt is completed.

[0162] Example 2

[0163] This embodiment provides a method for preparing a composite carbon-carbon thermal insulation rigid felt, the method comprising the following steps:

[0164] (A) Preparation of soft felt

[0165] Opening: Use mixed short carbon wires with a length of 70-90mm; put the mixed short carbon wires of different lengths into a mixing container and achieve preliminary mixing of short carbon wires of different lengths by mechanical stirring (65rpm, 5min); pour the mixed short carbon wires that have completed the preliminary mixing onto the drive curtain of the opening machine, pass through a metal impurity remover, and feed into a multi-roller opening machine to achieve opening and mixing of short carbon wires (6 pairs of opening rollers, opening roller parameters set to 16Hz, cylinder speed set to 45Hz);

[0166] Web Formation: After the fibers are opened by the multi-roller opener, they are sent into the cotton box by high-speed airflow. The opened fiber clumps are lifted upward by the conveying nail curtain to the leveling roller and the drop roller. After being homogenized and metered by the leveling roller, the fiber clumps are stripped by the drop roller and transferred to the vibrating plate. The vibration of the vibrating plate causes the fiber clumps to fall and be evenly stacked on the conveyor curtain to form a continuous fiber clump. After being metered by the precision metering device, the continuous fiber clumps are sent into the high-speed cylinder by the feed roller (the cylinder speed is set to 1200 rpm). The cylinder combs the fiber clumps at high speed to form a fiber web. The fiber web is adsorbed by the air curtain with negative pressure and stripped from the high-speed cylinder to form a highly disordered, isotropic, continuous fiber web with a certain strength.

[0167] Composite reinforcement: The carbon fiber mesh is fed into the reciprocating web laying curtain through the conveyor curtain. The carbon fiber mesh passes through the feeding curtain, the ring curtain, the reciprocating curtain, and the output clamping roller of the reciprocating web laying machine in sequence. It is then laid in a Z-shaped reciprocating manner according to the parameter setting value, and then needle-punched for reinforcement and cut to obtain soft felt.

[0168] The Z-shaped repetitive layering was set to 18 layers, and the needle reinforcement density was 18 needles / cm. 2 A surface density of 900 g / m³ can be obtained. 2 Soft felt;

[0169] The Z-shaped reciprocating layering was set to 24 layers, and the needle reinforcement density was 22 needles / cm. 2 A surface density of 1200 g / m³ can be obtained. 2 Soft felt.

[0170] (B) Preparation of the reinforcing layer

[0171] Preparation of the reinforcing layer mesh: Mixed short-cut carbon wires with a length of 70-90mm are placed in a roller carding machine for opening and carding (cylinder speed set to linear speed of 1200m / min, work roll linear speed of 70m / min, number of work rolls: 6 sets), and needle punching (needle punching density of 10 needles / cm). 2 The needles are inserted upwards, perpendicular to the fiber web, to form a reinforcing mesh layer. The surface density of this mesh layer is 180 g / m². 2 ;

[0172] Pressing of the reinforcing layer: Using a peristaltic pump and a resin spraying device with a gear pump, the surface of the single-layer reinforcing mesh is sprayed with phenolic resin liquid one with a viscosity of 800 cps and a residual carbon rate of 43%, at a spraying mass ratio of 1:1.5. After spraying, it is left to stand in a container with polytetrafluoroethylene for 1 hour. After standing, the entire container is transferred to a vibrating screen (vibration frequency of 15 Hz), and phenolic resin powder two with a residual carbon rate of 57% is applied to the surface of the mesh after spraying phenolic resin liquid one, at a mass ratio of 1:0.7. After two applications of phenolic resin, the mesh is stacked sequentially, covered with a high-temperature resistant cloth with a polytetrafluoroethylene surface, and cured and pressed at a pressing temperature of 170℃ and a compression ratio of 7.0.

[0173] With 5 layers of mesh fabric stacked together, a single sheet thickness of 1.5 mm and a surface density of 1000 ± 50 g / m³ can be obtained. 2 The reinforcing layer.

[0174] (C) Preparation of composite layer containing buffer layer and reinforcing layer

[0175] The single sheet obtained in step (A) has a thickness of 15 mm and an areal density of 1200 g / m³. 2 Its density is 0.085 g / cm³. 3 The soft felt was coated with a phenolic resin solution with a viscosity of 12000 cps and a residual carbon rate of 47% using a pneumatic spray gun, with a spraying amount of 250 g / m². 2 Resin is applied only to the upper surface of the soft felt; after the surface resin is applied, the cured and pressed reinforcing layer and the high-temperature resistant cloth with polytetrafluoroethylene are placed on top, and high-temperature curing is performed using a press at a curing temperature of 220°C with no compression ratio, thus completing the composite shaping of the buffer layer and the reinforcing layer.

[0176] (D) Preparation of carbon-carbon thermal insulation felt matrix

[0177] Spray adhesive curing: Select a single sheet with a thickness of 10 mm and an areal density of 900 g / m³ obtained in step (A). 2 Its density is 0.090 g / cm³. 3 The soft felt is sprayed with adhesive. The soft felt is pushed into the adhesive spraying device. The total adhesive spraying ratio is soft felt to water-soluble phenolic resin liquid four = 1:2.5. The viscosity of the water-soluble phenolic resin liquid four is 300cps and the resin residual carbon content is 34%. Double-sided adhesive spraying is performed. After the adhesive spraying is completed, the soft felt is dried in a hot air (temperature of 120℃) penetrating oven with a radiant pre-drying device.

[0178] Lamination and Hot Pressing: After the soft felt is dried, a phenolic resin liquid with a viscosity of 12000 cps and a residual carbon rate of 47% is applied to the surface of each soft felt using pneumatic spraying, with a spraying amount of 250 g / m².2 After applying phenolic resin liquid with a viscosity of 12000cps and a residual carbon rate of 47% in three spray applications, the soft felt is laid up in sequence (10 layers) and transferred as a whole to the press for hot pressing and curing. The curing temperature is 220℃ and the compression ratio is 1.2:1 to make carbon carbon insulation felt matrix.

[0179] (E) Preparation of composite carbon-carbon thermal insulation felt

[0180] Apply a third coat of phenolic resin solution with a viscosity of 12000 cps and a residual carbon content of 47% at a rate of 250 g / m² to the surface of the completed carbon-carbon insulation felt substrate. 2 After the adhesive is applied, the soft felt surface of the buffer layer and reinforcing layer composite is bonded to the upper surface of the carbon-carbon insulation felt. After the buffer layer and reinforcing layer composite is bonded to the carbon-carbon insulation felt substrate, a high-temperature resistant cloth with polytetrafluoroethylene is placed on top, and a press is used for high-temperature curing at 220°C with no compression ratio. This completes the hot-pressing bonding of the buffer layer and reinforcing layer composite with the carbon-carbon insulation felt substrate, resulting in the composite carbon-carbon insulation felt.

[0181] (F) Preparation of composite carbon-carbon thermal insulation felt

[0182] Carbonization treatment: 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; nitrogen is introduced into the carbonization furnace, and after the nitrogen is introduced for 4 hours, the temperature is raised. The corresponding process curve is set, and the total time is 29.5 hours to raise the temperature to 950℃, hold the temperature for 5 hours, and then cool down to 60℃ to obtain carbon felt.

[0183] High-temperature treatment: The carbon felt is placed in a high-temperature furnace and treated at 2300℃; the furnace is evacuated to a vacuum level of -0.1 MPa and argon gas is introduced. The corresponding process curve is set, and the total time is 50 hours. The temperature is raised to 2300℃ and held for 20 hours. Then the temperature is lowered to 60℃. The production of the carbon-carbon thermal insulation hard felt is completed.

[0184] Example 3

[0185] This embodiment provides a method for preparing a composite carbon-carbon thermal insulation rigid felt, the method comprising the following steps:

[0186] (A) Preparation of soft felt

[0187] Opening: Use mixed short carbon wires with a length of 50-60mm; put the mixed short carbon wires of different lengths into a mixing container and achieve preliminary mixing of short carbon wires of different lengths by mechanical stirring (75rpm, 3min); pour the mixed short carbon wires that have completed the preliminary mixing onto the drive curtain of the opening machine, pass through a metal impurity remover, and feed into a multi-roller opening machine to achieve opening and mixing of short carbon wires (6 pairs of opening rollers, opening roller parameters set to 14Hz, cylinder speed set to 48Hz);

[0188] Web Formation: After the fibers are opened by the multi-roller opener, they are sent into the cotton box by high-speed airflow. The opened fiber clumps are lifted upward by the conveying nail curtain to the leveling roller and the drop roller. After being uniformized and metered by the leveling roller, the fiber clumps are stripped by the drop roller and transferred to the vibrating plate. The vibration of the vibrating plate causes the fiber clumps to fall and be evenly stacked on the conveyor curtain to form a continuous fiber clump. After being metered by the precise metering device, the continuous fiber clumps are sent into the high-speed cylinder by the feed roller (the cylinder speed is set to 1300 rpm). The cylinder combs the fiber clumps at high speed to form a fiber web. The fiber web is adsorbed by the air curtain with negative pressure and stripped from the high-speed cylinder to form a highly disordered, isotropic, continuous fiber web with a certain strength.

[0189] Composite reinforcement: The carbon fiber mesh is fed into the reciprocating web laying curtain through the conveyor curtain. The carbon fiber mesh passes through the feeding curtain, the ring curtain, the reciprocating curtain, and the output clamping roller of the reciprocating web laying machine in sequence. It is then laid in a Z-shaped reciprocating manner according to the parameter setting value, and then needle-punched for reinforcement and cut to obtain soft felt.

[0190] The Z-shaped repetitive layering was set to 18 layers, and the needle reinforcement density was 18 needles / cm. 2 A surface density of 900 g / m³ can be obtained. 2 Soft felt;

[0191] The Z-shaped reciprocating layering was set to 24 layers, and the needle reinforcement density was 22 needles / cm. 2 A surface density of 1200 g / m³ can be obtained. 2 Soft felt.

[0192] (B) Preparation of the reinforcing layer

[0193] Preparation of the reinforcing layer mesh: Mixed short-cut carbon wires with a length of 50-60mm are placed in a roller carding machine for opening and carding (cylinder speed set to linear speed of 1100m / min, work roll linear speed of 50m / min, number of work rolls: 8 sets), and needle punching (needle punching density of 15 needles / cm). 2 The needles are inserted upwards, perpendicular to the fiber web, to form a reinforcing mesh layer. The surface density of this mesh layer is 220 g / m². 2 ;

[0194] Pressing of the reinforcing layer: Using a peristaltic pump and a resin spraying device with a gear pump, the surface of the single-layer reinforcing mesh is sprayed with phenolic resin liquid one with a viscosity of 800 cps and a residual carbon rate of 43%, at a spraying mass ratio of 1:1.5. After spraying, it is left to stand in a container with polytetrafluoroethylene for 1 hour. After standing, the entire container is transferred to a vibrating screen (vibration frequency of 15 Hz), and phenolic resin powder two with a residual carbon rate of 57% is applied to the surface of the mesh after spraying phenolic resin liquid one, at a mass ratio of 1:0.7. After two applications of phenolic resin, the mesh is stacked sequentially, covered with a high-temperature resistant cloth with a polytetrafluoroethylene surface, and cured and pressed at a pressing temperature of 180℃ and a compression ratio of 6.8.

[0195] With 5 layers of mesh fabric stacked together, a single sheet thickness of 1.5 mm and a surface density of 1100 ± 50 g / m³ can be obtained. 2 The reinforcing layer.

[0196] (C) Preparation of composite layer containing buffer layer and reinforcing layer

[0197] The single sheet obtained in step (A) has a thickness of 15 mm and an areal density of 1200 g / m³. 2 Its density is 0.085 g / cm³. 3 The soft felt was coated with a phenolic resin solution with a viscosity of 12000 cps and a residual carbon rate of 47% using a pneumatic spray gun, with a spraying amount of 250 g / m². 2 Resin is applied only to the upper surface of the soft felt; after the surface resin is applied, the cured and pressed reinforcing layer and the high-temperature resistant cloth with polytetrafluoroethylene are placed on top, and high-temperature curing is performed using a press at a curing temperature of 220°C with no compression ratio, thus completing the composite shaping of the buffer layer and the reinforcing layer.

[0198] (D) Preparation of carbon-carbon thermal insulation felt matrix

[0199] Spray adhesive curing: Select a single sheet with a thickness of 10 mm and an areal density of 900 g / m³ obtained in step (A). 2 Its density is 0.090 g / cm³. 3 The soft felt is sprayed with adhesive. The soft felt is pushed into the adhesive spraying device. The total adhesive spraying ratio is soft felt to water-soluble phenolic resin liquid four = 1:2.5. The viscosity of the water-soluble phenolic resin liquid four is 300cps and the resin residual carbon content is 34%. Double-sided adhesive spraying is performed. After the adhesive spraying is completed, the soft felt is dried in a hot air (temperature of 120℃) penetrating oven with a radiant pre-drying device.

[0200] Lamination and Hot Pressing: After the soft felt is dried, a phenolic resin liquid with a viscosity of 12000 cps and a residual carbon rate of 47% is applied to the surface of each soft felt using pneumatic spraying, with a spraying amount of 250 g / m².2 After applying phenolic resin liquid with a viscosity of 12000cps and a residual carbon rate of 47% in three spray applications, the soft felt is laid up in sequence (10 layers) and transferred as a whole to the press for hot pressing and curing. The curing temperature is 220℃ and the compression ratio is 1.2:1 to make carbon carbon insulation felt matrix.

[0201] (E) Preparation of composite carbon-carbon thermal insulation felt

[0202] Apply a third coat of phenolic resin solution with a viscosity of 12000 cps and a residual carbon content of 47% at a rate of 250 g / m² to the surface of the completed carbon-carbon insulation felt substrate. 2 After the adhesive is applied, the soft felt surface of the buffer layer and reinforcing layer composite is bonded to the upper surface of the carbon-carbon insulation felt. After the buffer layer and reinforcing layer composite is bonded to the carbon-carbon insulation felt substrate, a high-temperature resistant cloth with polytetrafluoroethylene is placed on top, and a press is used for high-temperature curing at 220°C with no compression ratio. This completes the hot-pressing bonding of the buffer layer and reinforcing layer composite with the carbon-carbon insulation felt substrate, resulting in the composite carbon-carbon insulation felt.

[0203] (F) Preparation of composite carbon-carbon thermal insulation felt

[0204] Carbonization treatment: 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; nitrogen is introduced into the carbonization furnace, and after the nitrogen is introduced for 4 hours, the temperature is raised. The corresponding process curve is set, and the total time is 29.5 hours to raise the temperature to 950℃, hold the temperature for 5 hours, and then cool down to 80℃ to obtain carbon felt.

[0205] High-temperature treatment: The carbon felt is placed in a high-temperature furnace and treated at 2300℃; the high-temperature furnace is evacuated to a vacuum degree of -0.1Mpa, and argon gas is introduced. The corresponding process curve is set, and the total time is 50h. The temperature is raised to 2300℃ and held for 20h. Then the temperature is lowered to 80℃. The production of the carbon-carbon thermal insulation hard felt is completed.

[0206] Example 4

[0207] This embodiment provides a method for preparing a composite carbon-carbon thermal insulation rigid felt, which differs from Embodiment 1 only in that a surface density of 900 g / m³ is used. 2 The soft felt was replaced with a surface density of 800 g / m². 2 The soft felt has a surface density of 1200 g / m². 2 The soft felt was replaced with a surface density of 1100 g / m². 2 The soft felt is made, and the other steps are exactly the same as in Example 1.

[0208] Example 5

[0209] This embodiment provides a method for preparing a composite carbon-carbon thermal insulation rigid felt, which differs from Embodiment 1 only in that a surface density of 900 g / m³ is used. 2 The soft felt was replaced with a surface density of 1000 g / m². 2 The soft felt has a surface density of 1200 g / m². 2 The soft felt was replaced with a surface density of 1300 g / m². 2 The soft felt is made, and the other steps are exactly the same as in Example 1.

[0210] Example 6

[0211] This embodiment provides a method for preparing a composite carbon-carbon thermal insulation rigid felt. The only difference from Embodiment 1 is that the length of the mixed chopped carbon filaments is 40-120 mm, wherein the proportion of chopped carbon filaments with a length of 40-60 mm is 60 wt%, the proportion of chopped carbon filaments with a length of 100-120 mm is 20 wt%, and the proportion of chopped carbon filaments with a length of 60-100 mm is 20 wt%. The other steps are completely the same as in Embodiment 1.

[0212] Example 7

[0213] This embodiment provides a method for preparing a composite carbon-carbon thermal insulation rigid felt. The only difference from Embodiment 1 is that the length of the mixed chopped carbon filaments is 40-120 mm, wherein the proportion of chopped carbon filaments with a length of 40-60 mm is 40 wt%, the proportion of chopped carbon filaments with a length of 100-120 mm is 5 wt%, and the proportion of chopped carbon filaments with a length of 60-100 mm is 55 wt%. The other steps are completely the same as in Embodiment 1.

[0214] Comparative Example 1

[0215] This comparative example provides a method for preparing carbon-carbon thermal insulation rigid felt. The only difference from Example 1 is that no reinforcing layer is set, and the buffer layer and the carbon-carbon thermal insulation felt substrate are directly bonded together. The other steps are the same as in Example 1.

[0216] Comparative Example 2

[0217] This comparative example provides a method for preparing carbon-carbon thermal insulation rigid felt. The only difference from Example 1 is that no buffer layer is set, and the reinforcing layer and the carbon-carbon thermal insulation felt substrate are directly bonded together. The other steps are the same as in Example 1.

[0218] Comparative Example 3

[0219] This comparative example provides a method for preparing a composite carbon-carbon thermal insulation rigid felt. The only difference from Example 1 is that in the preparation process of the reinforcing layer, the phenolic resin liquid with a residual carbon rate of 43% is replaced with phenolic resin liquid with a residual carbon rate of 34%, and the spraying mass ratio is 1:2. The other steps are the same as in Example 1.

[0220] Comparative Example 4

[0221] This comparative example provides a method for preparing a composite carbon-carbon thermal insulation rigid felt. The only difference from Example 1 is that in the preparation process of the reinforcing layer, the phenolic resin liquid with a residual carbon rate of 43% is replaced with phenolic resin liquid with a residual carbon rate of 47%, and the spraying mass ratio is 1:2. The other steps are the same as in Example 1.

[0222] Comparative Example 5

[0223] This comparative example provides a method for preparing a composite carbon-carbon thermal insulation rigid felt. The only difference from Example 1 is that, during the preparation of the reinforcing layer, a phenolic resin liquid with a viscosity of 800 cps and a residual carbon rate of 43% is applied at a spraying mass ratio of 1:2. After spraying, the solution is left to stand in a container with polytetrafluoroethylene for 1 hour. After standing, no more phenolic resin powder is applied. The other steps are the same as in Example 1.

[0224] Comparative Example 6

[0225] This comparative example provides a method for preparing a composite carbon-carbon thermal insulation rigid felt. The only difference from Example 1 is that, in the preparation process of the reinforcing layer, phenolic resin liquid one is no longer sprayed, but phenolic resin powder two is directly applied to the single-layer reinforcing mesh, and the application mass ratio is increased to 1:2. The other steps are the same as in Example 1.

[0226] Comparative Example 7

[0227] This comparative example provides a method for preparing a composite carbon-carbon thermal insulation rigid felt. The only difference from Example 1 is that, in the preparation process of the composite layer containing the buffer layer and the reinforcing layer, the phenolic resin liquid three with a residual carbon rate of 47% is replaced with phenolic resin liquid one with a residual carbon rate of 43%. The other steps are the same as in Example 1.

[0228] Comparative Example 8

[0229] This comparative example provides a method for preparing a composite carbon-carbon thermal insulation rigid felt. The only difference from Example 1 is that, in the preparation process of the composite layer containing the buffer layer and the reinforcing layer, the phenolic resin liquid with a residual carbon rate of 47% is replaced with a phenolic resin liquid with a residual carbon rate of 57%. The other steps are the same as in Example 1.

[0230] Test Example 1

[0231] Test samples: Composite carbon-carbon thermal insulation felt provided in Examples 1 to 7.

[0232] Test methods: GB / T 10295-2008 Determination of steady-state thermal resistance and related properties of thermal insulation materials by heat flow meter method, GB / T 3365-2008 Test method for porosity of carbon fiber reinforced plastics, ASTM C559-2016 Standard test method for determination of bulk density of carbon and graphite materials.

[0233] The specific test results are shown in Table 1:

[0234] Table 1

[0235]

[0236] Test Example 2

[0237] Test samples: Composite carbon-carbon thermal insulation felt provided in Examples 1-7 and Composite carbon-carbon thermal insulation felt provided in Comparative Examples 1-8.

[0238] Test methods: GB / T 33501-2017 "Test method for tensile properties of carbon / carbon composites" and GB / T 3356-2014 "Test method for bending properties of oriented fiber reinforced polymer matrix composites".

[0239] The specific test results are shown in Table 2:

[0240] Table 2

[0241]

[0242]

[0243] As shown in Table 2, the carbon-carbon thermal insulation rigid felt provided by this invention has a tensile strength of over 105 MPa, a flexural strength of over 208 MPa, and a service life of over 180 days. Examples 1-3 are preferred embodiments, providing carbon-carbon thermal insulation rigid felts with tensile strengths of over 118 MPa, flexural strengths of over 217 MPa, and a service life of over 180 days. This fully demonstrates that the multi-layer composite structure of the high-density reinforcing layer, low-density buffer layer, and carbon-carbon thermal insulation rigid felt matrix adopted in this invention, and the addition of a high-density erosion-resistant reinforcing layer and a low-density, high-specific-surface-area buffer layer to the surface of the traditional carbon-carbon thermal insulation rigid felt through high-temperature composite, greatly improves the service life of the carbon-carbon thermal insulation rigid felt under special working conditions such as high temperature, high-speed airflow erosion, and corrosive steam. The overall service life can reach more than 6 times that of traditional carbon-carbon thermal insulation rigid felt.

[0244] 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 or all of the technical features; and these modifications or substitutions 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 method for preparing a composite carbon-carbon thermal insulation rigid felt, characterized in that, The preparation method includes: Preparation of soft felt: Short-cut carbon fiber filaments are opened and formed into a web to obtain a carbon fiber web; the carbon fiber web is then laid in a Z-shaped reciprocating pattern and reinforced by needle punching to obtain a surface density of 800~1300 g / m². 2 Soft felt; Preparation of the reinforcing layer: Short carbon fiber filaments are opened and needle-punched to obtain an areal density of 150~250 g / m². 2 The reinforcing layer mesh is formed by applying a phenolic resin liquid with a residual carbon content of 40-45% to the surface of a single piece of the reinforcing layer mesh at a ratio of 1:(1.4-1.6), followed by applying phenolic resin powder with a residual carbon content of 55-60% at a ratio of 1:(0.6-0.8). The single pieces of mesh after the two applications of phenolic resin are then stacked, cured, and pressed to obtain the reinforcing layer. Preparation of composite layer: surface density of 1100~1300 g / m 2 A phenolic resin solution with a residual carbon content of 46-50% is applied to the surface of the soft felt, and the amount of adhesive applied is 240-260 g / m². 2， The reinforcing layer is covered and then cured to obtain a composite layer of buffer layer and reinforcing layer; Preparation of carbon-carbon thermal insulation felt matrix: for single sheet with a surface density of 800~1100 g / m 2 A phenolic resin liquid with a residual carbon content of 30-35% is applied to both sides of the soft felt. After curing, a phenolic resin liquid with a residual carbon content of 46-50% is applied to one side of the soft felt. The single soft felts with the phenolic resin applied are stacked, cured and pressed to obtain a carbon-carbon thermal insulation felt matrix. Preparation of composite carbon-carbon thermal insulation felt: A phenolic resin liquid with a residual carbon rate of 46-50% is applied to the surface of the carbon-carbon thermal insulation felt matrix, covering the composite layer, and cured to obtain composite carbon-carbon thermal insulation felt; Preparation of composite carbon-carbon thermal insulation rigid felt: The composite carbon-carbon thermal insulation felt is carbonized and subjected to high temperature treatment to obtain composite carbon-carbon thermal insulation rigid felt; The composite carbon-carbon thermal insulation rigid felt includes a reinforcing layer, a buffer layer, and a carbon-carbon thermal insulation rigid felt matrix stacked in sequence.

2. The method for preparing the composite carbon-carbon thermal insulation rigid felt according to claim 1, characterized in that, In the preparation process of the soft felt, the chopped carbon fiber filaments are selected from mixed chopped carbon filaments with a length of 40~120 mm; and in the mixed chopped carbon filaments: the proportion of chopped carbon filaments with a length <60 mm is <50 wt%, and the proportion of chopped carbon filaments with a length >100 mm is ≥10 wt%; And / or, in the preparation process of the soft felt, the opening step includes: stirring the chopped carbon fiber filaments to obtain a preliminary mixed carbon filament; opening the preliminary mixed carbon filament through a multi-roller opening machine to obtain a mixed carbon filament; wherein, the stirring speed is 65~75 rpm, and the stirring time is 3~5 min; the parameters of the multi-roller opening machine include: 4~8 pairs of opening rollers, the frequency of the opening rollers is 10~20 Hz, and the frequency of the cylinder is 40~50 Hz; And / or, in the preparation process of the soft felt, the web-forming step includes: feeding the loosened mixed carbon filaments into a cotton box via a high-speed airflow to form fiber clusters, combing them with a high-speed cylinder to form a fiber web, and peeling them off from the high-speed cylinder via negative pressure adsorption to obtain a carbon fiber web; wherein, the rotation speed of the high-speed cylinder is 1200~1300 rpm; the negative pressure adsorption is provided by fans on both sides, and the frequency of the fans is 30~40 Hz; And / or, during the preparation of the soft felt, when the areal density of the soft felt is 1100~1300 g / m³ 2 At that time, the number of reciprocating layers is 22 to 26, and the density of the needle reinforcement is 15 to 25 needles / cm. 2 When the areal density of the soft felt is 800~1100 g / m³ 2 At that time, the number of reciprocating layers is 16 to 22, and the density of the needle reinforcement is 15 to 25 needles / cm. 2 .

3. The method for preparing the composite carbon-carbon thermal insulation rigid felt according to claim 1, characterized in that, In the preparation of the reinforcing layer, the chopped carbon fiber filaments are selected from mixed chopped carbon filaments with a length of 40~120 mm; And / or, in the process of preparing the reinforcing layer, the opening step includes: opening and carding the chopped carbon fiber filaments through a roller carding machine to obtain mixed carbon filaments; wherein, the parameters of the roller carding machine include: 6 to 8 sets of working rollers, a working roller linear speed of 50 to 70 m / min, and a cylinder linear speed of 1100 to 1200 m / min. And / or, in the preparation process of the reinforcing layer, the needle punching step includes: needle punching the loosened mixed carbon wire to obtain an areal density of 150~250 g / m². 2 The reinforcing mesh layer; wherein the needle-punching density is 10-15 needles / cm. 2 ; And / or, in the preparation process of the reinforcing layer, the step of applying a phenolic resin liquid with a residual carbon rate of 40-45% includes: spraying the surface of the single piece of the reinforcing layer mesh and then letting it stand; wherein, the viscosity of the phenolic resin liquid is <1000cps; and the standing time is 0.5-2 h. And / or, in the preparation process of the reinforcing layer, the step of applying phenolic resin powder with a residual carbon content of 55-60% includes: applying phenolic resin liquid to the surface of the reinforcing layer mesh under vibration conditions, and then applying phenolic resin powder with a residual carbon content of 55-60%; wherein the vibration frequency is 13-18 Hz. And / or, during the preparation of the reinforcing layer, the number of stacked layers is 4 to 10; And / or, during the preparation of the reinforcing layer, the curing and pressing temperature is 170~180℃, and the compression ratio of the curing and pressing is ≥6.

5.

4. The method for preparing the composite carbon-carbon thermal insulation rigid felt according to claim 1, characterized in that, In the preparation process of the composite layer, the step of applying a phenolic resin liquid with a residual carbon content of 46-50% includes: applying the phenolic resin liquid with a residual carbon content of 46-50% to a surface density of 1100-1300 g / m² using a pneumatic spray gun. 2 The surface of the soft felt; wherein the thickness of the soft felt is ≥15 mm and the density is ≤0.085 g / cm³. 3 The viscosity of the phenolic resin solution is ≥10000 cps. And / or, the curing temperature is 210~230℃.

5. The method for preparing the composite carbon-carbon thermal insulation rigid felt according to claim 1, characterized in that, In the preparation process of the carbon-carbon thermal insulation felt matrix, the step of applying a phenolic resin liquid with a residual carbon content of 30-35% includes: applying the phenolic resin liquid with a residual carbon content of 30-35% to a surface density of 800-1100 g / m² using a spraying device. 2 The soft felt has two sides; wherein the thickness of the soft felt is ≥10 mm and the density is ≤0.090 g / cm³. 3 The viscosity of the phenolic resin solution is ≤400 cps; the applied material-to-liquid ratio is 1:(2.4~2.6). And / or, during the preparation of the carbon-carbon thermal insulation felt matrix, the curing temperature is 210~230℃; And / or, in the preparation process of the carbon-carbon thermal insulation felt matrix, the step of applying a phenolic resin liquid with a residual carbon content of 46-50% includes: applying the phenolic resin liquid with a residual carbon content of 46-50% to the surface of the soft felt using a pneumatic spray gun; wherein the viscosity of the phenolic resin liquid is ≥10000 cps; and the amount of adhesive applied is 240-260 g / m³. 2 ; And / or, during the preparation of the carbon-carbon thermal insulation felt matrix, the number of layers stacked is 5 to 65; And / or, during the preparation of the carbon-carbon thermal insulation felt matrix, the curing and pressing temperature is 210~230℃, and the compression ratio of the curing and pressing is (1.15~1.3):

1.

6. The method for preparing the composite carbon-carbon thermal insulation rigid felt according to claim 1, characterized in that, In the preparation process of the composite carbon-carbon insulation felt, the step of applying a phenolic resin liquid with a residual carbon content of 46-50% includes: applying the phenolic resin liquid with a residual carbon content of 46-50% to the surface of the carbon-carbon insulation felt substrate using a pneumatic spray gun; wherein the viscosity of the phenolic resin liquid is ≥10000 cps; and the amount of adhesive applied is 240-260 g / m³. 2 ; And / or, the curing temperature is 210~230℃.

7. The method for preparing the composite carbon-carbon thermal insulation rigid felt according to claim 1, characterized in that, The carbonization process includes: A protective gas is introduced into the carbonization furnace. After 3-5 hours of this process, the temperature is raised. The corresponding process curve is set, and the total time is 29-30 hours to raise the temperature to 940-960℃. The temperature is then maintained at 940-960℃ for 4-6 hours. Finally, the temperature is lowered to 60-80℃ to stop the carbonization process.

8. The method for preparing the composite carbon-carbon thermal insulation rigid felt according to claim 1, characterized in that, The high-temperature treatment procedure includes: The high-temperature furnace is evacuated to a vacuum level below -0.1 MPa. A protective gas is introduced, and the corresponding process curve is set. The total time is 48~52 hours to raise the temperature to 2250~2350℃, and then the temperature is held at 2250~2350℃ for 18~22 hours. The high-temperature treatment is then stopped by cooling the temperature down to 60~80℃.

9. A composite carbon-carbon thermal insulation rigid felt, characterized in that, The composite carbon-carbon thermal insulation rigid felt comprises a reinforcing layer, a buffer layer, and a carbon-carbon thermal insulation rigid felt matrix stacked sequentially; and the composite carbon-carbon thermal insulation rigid felt is prepared by the method for preparing composite carbon-carbon thermal insulation rigid felt according to any one of claims 1 to 8. The density of the reinforcing layer is 1.35~1.45 g / cm³. 3 The density of the buffer layer is 0.080~0.085 g / cm³. 3 The density of the carbon-carbon thermal insulation felt matrix is ​​0.15~0.17 g / cm³. 3 .

10. The composite carbon-carbon thermal insulation rigid felt according to claim 9, characterized in that, The thickness of the reinforcing layer is 1~6.5 mm, the thickness of the buffer layer is 5~15 mm, and the thickness of the carbon-carbon thermal insulation felt substrate is 20~300 mm. And / or, the porosity of the reinforcing layer is 15-20%, the porosity of the buffer layer is 95-96%, and the porosity of the carbon-carbon thermal insulation felt matrix is ​​90-92%; And / or, the thermal conductivity of the buffer layer is 0.05~0.10 W / mk, and the thermal conductivity of the carbon-carbon insulating felt matrix is ​​0.17~0.25 W / mk.

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