Fiber composite felt

Abstract

The invention relates to a fiber composite felt and a method for producing a curved fiber composite felt.

Description

Technical Field

[0001] This invention relates to a fiber composite felt and a method for producing a curved fiber composite felt. Background Technology

[0002] In high-temperature applications, such as furnaces used in the semiconductor, fiber optic, solar energy, and heat treatment industries, insulation materials made from carbon-based composite felts are widely favored for their superior insulation performance, chemical resistance, and long-term stability, even under harsh temperatures and severe conditions.

[0003] Composite felts used in high-temperature applications, especially carbon-based composite felts, are generally classified into soft felts and hard felts. Depending on the application, required insulation performance, the object to be insulated, and installation or replacement requirements, users can use soft felts, hard felts, or a combination of both.

[0004] Soft felt is typically made from needle-punched rayon or oxidized PAN fibers, and then heat-treated to become carbon soft felt. Its flexibility allows it to perfectly adapt to different shapes, and its ease of processing makes it suitable for a wide range of applications.

[0005] On the other hand, rigid felt is typically produced by pressing fibrous materials and carbon-based binders, followed by at least one (if not multiple) high-temperature treatment. Rigid felt assemblies are favored for their ease of installation and handling, as well as their excellent mechanical strength; however, the final shape of rigid felt is often determined by the machining process. Due to its complex geometry, the final machining of felt requires sophisticated machinery and often results in significant waste. Furthermore, the machined parts typically undergo further heat treatment, especially when their shape contains voids, which generates substantial dead volume in high-temperature furnaces, leading to high energy consumption and high costs.

[0006] In view of the above, the present invention aims to provide a fiber composite felt that overcomes the aforementioned problems of known composite materials (especially known rigid composite felts) in the prior art. Specifically, the present invention aims to provide an improved rigid felt that can be produced in a more energy-efficient and economical manner while maintaining its thermal insulation and operational performance. Summary of the Invention

[0007] This invention achieves this objective through the composite felt described in claim 1. Specifically, the invention relates to a fiber composite felt for high-temperature applications, particularly for high-temperature furnaces, having one or more surfaces, wherein the fiber composite felt comprises:

[0008] The fibrous material is preferably in a nonwoven form and / or based on short fibers;

[0009] Carbon-based matrix materials, among which,

[0010] The fiber composite felt includes one or more grooves, wherein preferably, the one or more grooves are provided and designed to allow the fiber composite felt to be bent.

[0011] The fiber composite felt of the present invention comprises a fibrous material, preferably in a nonwoven form or based on short fibers, and a carbon-based matrix material. The fiber composite felt of the present invention is a rigid felt, preferably a rigid carbon felt. It includes one or more grooves that allow the fiber composite felt to be bent. A hinge portion is formed within the felt by means of the one or more grooves, which serves as a bending device. Thus, the original rigid felt can be formed, and a complex rigid felt structure including angular and bent portions can be constructed. The hinge portion, thinned by the grooves, acts as a movable hinge or an integral hinge; for example, by bringing the sidewalls of the grooves closer together, the free volume of the grooves can be reduced. In other words, the movable hinge allows the rigid portion it connects to bend along the axis of rotation, thereby reducing the free volume of the grooves. The free volume of the groove refers to the unoccupied space or void within the groove, i.e., the space between the groove walls. It represents the amount of space within the groove that can be filled with substance or material.

[0012] In this invention, "groove" has its conventional meaning in the art, referring to any cut, slit, separation, recess, division, etc., in an object. It does not completely cut through the object, nor does it divide it into two physically distinct objects. Instead, it maintains the object as a physical entity, but causes a certain area of ​​the object to have the ability to bend at the grooved portion.

[0013] In the context of this invention, the term "carbon-based" refers to a material with a carbon content of ≥50% by weight. Preferably, the matrix comprises carbonaceous materials, carbonized materials, graphite materials, graphitized materials, or mixtures thereof. The carbon content is preferably ≥70% by weight, more preferably ≥90% by weight, and most preferably 100% by weight.

[0014] In the context of this invention, the term "carbonaceous" refers to a carbon-containing material. "Carbonization" refers to a material that has undergone carbonization treatment, a process known in the art, which typically involves pyrolysis under an inert atmosphere to form a solid residue from organic matter with an increasing carbon content.

[0015] The term "graphitization" refers to graphitized carbon or carbon materials, which is the transformation of non-graphite solid carbon into carbon materials with a near-perfect three-dimensional hexagonal crystal with long-range order.

[0016] "Non-graphite" refers to carbon or carbon materials that are mainly composed of carbon elements, in which carbon atoms have a two-dimensional long-range ordered arrangement in a hexagonal planar network, but in the third direction there is no measurable crystallographic order except for near-parallel stacking.

[0017] In this invention, the term "graphite" refers to carbon or carbon materials in which long-range order of three-dimensional hexagonal crystals can be detected by diffraction.

[0018] The "matrix material" of the composite felt of this invention is used to partially embed and connect the fibers of the fibrous material. It acts as a matrix to hold the fibers in place and to transfer and distribute stress between the fibers, thereby providing a mechanically stable rigid structure.

[0019] The fiber composite felt of the present invention is suitable for high-temperature applications, i.e., applications where the temperature exceeds 800°C, particularly up to 3000°C. The fiber composite felt is particularly suitable for high-temperature thermal insulation applications. Examples include silicon carbide, PVD, or CVD furnaces, especially HTPVD or CVD furnaces; silicon Cheklaussky crystal pulling furnaces; gallium nitride, aluminum nitride, and sapphire crystal growth furnaces; silicon and silicon carbide epitaxial furnaces; vacuum furnaces for heat treatment of metal alloys and / or ceramics; sintering and debinding furnaces; optical fiber pulling furnaces; glass preform sintering furnaces; and battery powder production furnaces.

[0020] "Fiber material" refers to a material that contains or is composed of fibers. The term "fiber" in this field typically refers to a linear, linear structure, preferably part of a more complex textile structure such as a nonwoven fabric.

[0021] The fiber material of the fiber composite felt of the present invention is preferably selected from carbon fiber (especially graphite fiber), SiC fiber, Al2O3 fiber, or a combination thereof. Preferably, the fiber material is selected from carbon fiber (especially graphite fiber). The carbon fiber (especially graphite fiber) is preferably produced by carbonizing (and graphitizing, where applicable) a rayon precursor, an oxidized PAN (polyacrylonitrile) precursor, a phenolic fiber (novoloid) precursor, or a pitch precursor.

[0022] In a preferred embodiment, the fiber composite felt of the present invention is based on long fibers, i.e., the long fiber content is ≥50% by weight, preferably ≥70% by weight, more preferably ≥85% by weight, and most preferably ≥95% by weight. In a particularly preferred embodiment, the fiber material consists of long fiber material, i.e., fiber material with a fiber length of 20 to 100 mm. Long fibers are typically used in a nonwoven form, preferably as needle-punched felt, i.e., a felt in which the fiber structure entanglement is increased by inserting the fibers from the surface into the interior of the material using a needle punch. This needle-punched structure is particularly stable.

[0023] Using long-fiber materials can significantly reduce dust generation, which can be crucial in terms of environmental and health aspects of the production process. Furthermore, long-fiber materials also offer improved mechanical properties. However, for certain applications, economical short fibers are sufficient.

[0024] Preferably, the fiber material of the fiber composite felt of the present invention is based on short fibers, i.e., the short fiber content is ≥50% by weight, preferably ≥70% by weight, more preferably ≥85% by weight, even more preferably ≥90% by weight, and most preferably ≥95% by weight. In a particularly preferred embodiment, the fiber material consists of short fiber material, i.e., fiber material with a fiber length <20 mm. In a preferred embodiment, the fiber length L of the fiber material is in the range of 0.1 mm to <20 mm, more preferably in the range of 2 mm to <20 mm, even more preferably in the range of 5 to 10 mm, and most preferably in the range of 5 to 8 mm. The fiber length can be determined by suitable methods known to those skilled in the art, such as optical microscopy.

[0025] Carbon fiber rigid felt can be divided into rigid felt based on long fibers and rigid felt based on short fibers. Long fiber materials are obtained by impregnation, pressing, curing and heat treatment of fiber materials (preferably comprising or consisting of rayon, oxidized PAN, phenolic fibers, pitch fibers or mixtures thereof) and binder materials (selected from pitch or thermosetting resins, preferably phenolic resins, epoxy resins or furan resins or carbohydrates, especially sugars, starch or cellulose).

[0026] In the first sub-step, a soft felt is produced by carbonizing and graphitizing rayon, oxidized PAN, phenolic fiber, and / or pitch fiber material felts in an inert gas atmosphere. Subsequently, the soft felt is impregnated with liquid resin, laminated, wound, pressed, and cured, and then carbonized and graphitized again in an inert gas atmosphere to obtain a hard felt.

[0027] In the production of short-fiber carbon felt, rayon fibers are carbonized, the resulting product is ground, and then mixed with a binder material selected from bitumen; thermosetting resins, preferably phenolic resins, epoxy resins, or furan resins; or carbohydrates, especially sugars, starches, or cellulose. The mixture is then heat-treated again to obtain a rigid composite felt.

[0028] This invention combines the excellent properties of rigid felt, such as extremely low thermal conductivity, low mass, and low heat capacity, with the possibility of customizing rigid structures to suit the intended use. Grooves are provided to allow the composite felt to bend and shape, while the composite felt itself is rigid due to the adhesive used in the heat treatment. This enables the manufacture of complex structures with curved or angular portions, and can be customized to the furnace environment. Therefore, a variety of insulation applications can be addressed without complex and time-consuming processing techniques. This simplifies and accelerates the production process and eliminates safety and environmental concerns. Furthermore, the flexibility in geometry allows for the production of larger rigid felts, further improving production efficiency. Another significant advantage is the reduction in cost and time in the rigid felt manufacturing process. By using rigid composite felt and shaping it into the desired form, rather than processing it, for example, from block material, furnace space can be utilized more efficiently, and more fiber composite felt can be produced with the same furnace capacity. Moreover, the transport and storage of intermediate products, such as sheet-like rigid felt, are simplified because the final form typically contains empty spaces to allow it to wrap the object to be insulated. Conversely, complex-shaped, volume-filled products (e.g., hollow polygons or cylinders) are produced in the final stages of the manufacturing process, particularly after the energy-intensive carbonization and graphitization steps (for producing rigid felt), and after the limited capacity for transporting and storing intermediate products.

[0029] The grooves allow the rigid felt to bend by reducing the free volume of the grooves. Therefore, felts that are typically designed and configured to be completely rigid can be formed without damaging brittle materials.

[0030] One or more grooves may have different shapes, preferably selected from wedge, U-shape, T-shape, prism, dovetail, rectangular, or combinations thereof. The grooves may have different widths along their extension direction (i.e., from their opening to the bottom of the groove), wherein the groove width preferably decreases linearly or stepwise along their extension direction (i.e., toward the composite felt). Wedge-shaped grooves are particularly preferred because they allow for high flexibility and ensure minimal open space when bending along the groove direction. This ensures excellent thermal insulation and mechanical properties. One or more grooves may also have different shapes, or the shape of the grooves may vary along their length. This facilitates tailoring flexibility to the specific requirements of the application.

[0031] Preferably, the composite felt includes three or more grooves on one of its surfaces, wherein the grooves are preferably equidistantly arranged in the surface. This allows for the construction of symmetrical structures with high structural stability. A particularly preferred structure is one with more than 10 grooves in one surface, wherein the grooves are equidistantly arranged in said one surface.

[0032] In another particularly preferred embodiment, the grooves are not equidistantly distributed on a surface, i.e., they are asymmetrically arranged on a surface. This arrangement enables the formation of complex fiber composite felt shapes, such as elliptical hollow cylinders.

[0033] The invention is characterized by one or more grooves that facilitate the manufacture of shaped fiber composite felts, i.e., three-dimensional objects with significant extension in all spatial directions (length, width, and height). Hollow bodies are preferred, i.e., three-dimensional objects with empty spaces or gaps within their boundaries, such as hollow cylinders. Felts in geometrical matrix forms are particularly preferred, such as cylinders, cones, hollow cylinders, polygons, or rings. Therefore, fiber composite felts with one of the above structures are preferred. Most preferably, cylinders with polygonal cross-sections are preferred, such as icosagonal, sanguisagonal, or higher polygonal cross-sections. Preferably, the number of one or more grooves is equal to or greater than the number of side surfaces of a cylinder with a polygonal cross-section. For example, for a sanguisagonal cross-section, the number of grooves is preferably 30 or more.

[0034] Typically, these complex structures begin with a simple sheet of felt with one or more grooves, for example, by machining one or more grooves in one or more surfaces, and then bending (and optionally machining) it into the desired shape. In the bending process, preferably, the free volume of the grooves is reduced, for example, by moving the sidewalls of the grooves closer together. Preferably, the stiff felt can be bent until the sidewalls of one or more grooves are in at least partial contact. More preferably, the stiff felt can be bent until the sidewalls of one or more grooves are in complete contact. This flat, flexible sheet structure is readily available within the scope of existing manufacturing capabilities, making the method of obtaining complex structures according to the present invention particularly simple and economical.

[0035] In a particularly preferred embodiment, the fiber composite felt is in the form of a board. The board extends significantly less in one spatial direction (“height”) than in the other two directions (“length” and “width”). In this document, the terms “board” and “flat board” are used interchangeably. Preferably, the board has two flat surfaces and four side surfaces, and is flexible due to one or more grooves of the invention. Preferably, the thickness T of the board is… f The thickness (i.e., the height) is in the range of 10 mm to 500 mm, more preferably in the range of 50 mm to 300 mm, even more preferably in the range of 50 mm to 200 mm, and most preferably in the range of 50 mm to 100 mm. In this document, “thickness” / “height” refers only to the portion of the plate that is not thinned by one or more grooves.

[0036] The height of one or more grooves, i.e., their maximum elongation along the height of the plate, is preferably ≥ 50% of the total height of the plate, more preferably ≥ 65%, even more preferably ≥ 80%, and most preferably ≥ 90%, but less than 100%. A higher maximum elongation enhances the flexibility of the plate, but also increases the risk of breakage and allows for the path of least resistance to heat loss. Therefore, a particularly preferred maximum elongation is 65-95%.

[0037] The composite felt of the present invention may have one or more grooves arranged in one or more flat surfaces, one or more side surfaces, or both, depending on the specific application of the composite felt. In a preferred embodiment, one or more grooves are arranged in one of the two flat surfaces of the plate-like composite felt. Providing one or more grooves in one or more flat surfaces allows the plate to bend, thereby reducing the free volume of the grooves. In this bending process, by rotating about the longitudinal axis of the groove, the rigid portions other than the hinge segments thinned by the grooves can come closer to each other.

[0038] Generally, increasing the number of grooves allows for greater complexity of the structure obtained by bending the felt. Therefore, preferably, the felt contains two, three, four, five, or significantly more grooves, such as ≥30 or ≥40, particularly preferably in one of the flat surfaces.

[0039] In another preferred embodiment of the sheet-like composite felt, the composite felt comprises two or more grooves arranged in at least two surfaces, wherein, when the felt is in sheet form, these surfaces are preferably two opposing flat surfaces of a sheet. By introducing grooves in the two flat surfaces, the sheet can be bent in opposite directions, thereby allowing the formation of a wavy structure. In another preferred embodiment, two or more grooves are arranged in at least two surfaces, wherein at least one groove is arranged in a side surface, and at least another groove is arranged in a flat surface. In yet another preferred embodiment, two or more grooves are arranged in at least two surfaces, wherein the at least two surfaces are side surfaces.

[0040] In specific applications, the surfaces of the flexible composite felt (or multiple flexible composite felts) are preferably interconnected. For this purpose, the sheet-like composite felt typically includes connecting devices, which can be form-fit, force-fit, and / or material-fit connecting devices. Form-fit connecting devices are particularly preferred, consisting of interlocking interlocking connecting elements, wherein preferably, the connecting elements are independent, i.e., elements attached to grooves. Examples of such form-fit connecting devices are selected from labyrinth or mortise joints, tenon joints, finger joints, ring or segmental joints, and dovetail joints. In the case of sheet form, the connecting elements are preferably mounted to or located on two opposing side surfaces, i.e., on the "end faces" of the cylinder when the sheet is bent into a cylindrical shape. However, the connecting elements can also be located on other side surfaces or flat surfaces.

[0041] According to another embodiment of the invention, the connecting device is designed as a rectangular groove and a tenon that mates with it, each groove and tenon having sides that are inclined relative to each other to form an undercut. By providing the inclined sides, the "mortise and tenon" connection, which was originally only suitable for absorbing lateral forces, becomes a dovetail connection with an undercut, which can absorb both lateral and tensile forces.

[0042] For example, interlocking connecting devices can be used to stabilize closed cylindrical forms, which are obtained by bending a flat composite felt 360°, thereby reducing the free volume of the groove. The connecting device can also be used to connect two or more composite felts, for example, to form closed cylindrical forms, where each bent composite felt constitutes a segment forming the cylinder.

[0043] An advantageous embodiment of the invention specifies that, when measured at 2000°C according to DIN 51936, the thermal conductivity of the fiber composite felt (e.g., cylindrical fiber composite felt) is at most 1.5 W / (m·K), preferably at most 0.8 W / (m·K). Preferably, the thermal conductivity of the cylindrical composite felt is constant along the circumference, wherein "constant" means that the difference between the maximum and minimum thermal conductivity values ​​is 20% or less of the maximum thermal conductivity value, preferably 10% or less. This is sufficient to prevent heat loss in high-temperature systems. The thermal conductivity used herein refers to the thermal conductivity in the thickness direction.

[0044] According to another preferred embodiment of the invention, the compressive strength of the felt (measured according to DIN 51910 and DIN EN ISO20504) is at least 0.3 MPa, preferably at least 0.4 MPa, more preferably at least 0.6 MPa, and / or the flexural strength (measured according to DIN ISO EN 17138 and DIN 51902) is at least 0.3 MPa, preferably at least 0.5 MPa, more preferably at least 0.8 MPa.

[0045] Fiber composite felts may include one or more additional layers, preferably arranged as overlays on one or more surfaces of the fiber composite felt. These layers can improve structural stability, protect the fibrous material from unwanted permeation, improve reflectivity for optimal composite insulation, and improve the temperature distribution and breathability of the composite felt. One or more foils, such as graphite foil, are particularly preferred. To reliably protect the surface from mechanical and corrosive damage, the composite felt may be coated with a closed layer or mesh made of carbon fiber reinforced carbon or graphite slurry coating.

[0046] Because fiber composite felts can be bent using one or more grooves, they can be formed into structures with curved and / or angular cross-sections (i.e., felt bodies). This gives the composite material high flexibility to meet applications with different geometric requirements without complex and cumbersome processing techniques. Composite felt bodies can also be obtained by joining one or more bent composite felts together.

[0047] A particularly preferred form is a hollow cylinder comprising one or more curved composite felts. The inner diameter of the hollow cylinder of the felt is D. I The outer diameter is D O ,in The ratio is preferably in the range of 0.2 to 0.98, more preferably in the range of 0.25 to 0.95, and most preferably in the range of 0.3 to 0.95. O Preferably, the range is in the range of 10 to 2000 mm; more preferably, in the range of 200 to 1500 mm; and most preferably, in the range of 300 to 1350 mm. I Preferably, the range is from 4 to 1900 mm, more preferably from 100 to 1400 mm, and most preferably from 200 to 1250 mm.

[0048] Hollow shapes, particularly hollow cylindrical shapes, are preferably obtained by bending and connecting one or more sheet-like fiber composite felts as defined above, such that at least two opposing side surfaces are in contact, and securing the structure with additional fastening devices (e.g., rigid felt rings, CFRC (carbon fiber reinforced carbon) or metal rings, or any other locking device such as sleeves, wound fibers or ropes, or by winding soft felt layers). Another option for securing the structure with fastening devices or additional fastening devices is to use interlocking connecting devices, such as those previously defined, which are preferably located at the side surfaces.

[0049] In the case of forming a hollow cylinder, bending causes the fibers to be oriented at least partially tangent to the circumference of the hollow cylinder (forming a 90° angle with the interior and center of the hollow cylinder). This results in insulation performance comparable to that of a flat plate, thus ensuring optimal insulation performance for the hollow cylinder. This contrasts sharply with hollow cylinders obtained by processing bulk materials, which typically have poorer thermal properties because the fiber orientation varies by up to 100% along the circumference, leading to changes in thermal conductivity and insulation performance.

[0050] Preferably, the fiber orientation of the fiber material is tangent to the circumference of the hollow cylinder at four or more equidistant points, wherein the distance along the circumference of these equidistant points is preferably 0.01-0.25 times the circumference of the hollow cylinder, more preferably 0.02-0.125 times the circumference. In this document, a hollow cylinder refers to a hollow cylinder obtained by bending and, where appropriate, connecting multiple sheet-like fibers. This means that the term "circumference" does not necessarily refer to a "perfect" circle, but can also be a polygonal "circumference".

[0051] The composite felt of the present invention is suitable for and can be used in a variety of high-temperature applications, such as silicon carbide, PVD, or CVD furnaces, particularly HT PVD or CVD furnaces; silicon Cheklaussky crystal pulling furnaces; gallium nitride, aluminum nitride, and sapphire crystal growth furnaces; silicon and silicon carbide epitaxial furnaces; vacuum furnaces for heat treatment of metal alloys and / or ceramics; sintering and debinding furnaces; optical fiber pulling furnaces; glass preform sintering furnaces; and battery powder production furnaces. A preferred use is as a thermal insulation material for high-temperature applications (particularly those described above). In some embodiments, the composite felt is used in or as a lining, particularly an inner lining. The inner lining can be obtained in a simple manner by providing one or more grooves in a flat fiber composite felt and then bending the felt into a circular or angular structure to suit installation as an inner lining in a chamber. This results in a seamless structure with no (or reduced) joints prone to damage and heat loss. Therefore, using the composite felt lining of the present invention simplifies the furnace, provides a structure with lower energy consumption and longer service life, and also allows for quick replacement of the insulation zone, for example, during maintenance.

[0052] Therefore, the present invention relates to the use of fiber composite felt as insulation material and / or lining, particularly as lining for high-temperature applications; especially for silicon carbide, PVD or CVD furnaces, particularly HT PVD or CVD furnaces; silicon Czeklauski crystal pulling furnaces; gallium nitride, aluminum nitride and sapphire crystal growth furnaces; silicon and silicon carbide epitaxial furnaces; vacuum furnaces for heat treatment of metal alloys and / or ceramics; sintering and debinding furnaces; optical fiber pulling furnaces; glass preform sintering furnaces and battery powder production furnaces; and corresponding furnaces or pulling machines incorporating the composite felt of the present invention as insulation material, lining and / or lining.

[0053] The present invention also relates to a component kit, i.e., a system consisting of independent but functionally interacting individual components, for producing fiber composite felts or fiber composite felt bodies having one or more grooves, said system comprising:

[0054] a. Fiber materials, such as carbon fiber materials, preferably obtained by graphitized rayon, oxidized PAN, phenolic fibers and / or pitch fibers;

[0055] b. Adhesive material selected from bitumen or thermosetting resins, preferably phenolic resins, epoxy resins or furan resins, or carbohydrates, especially sugars, starches or cellulose.

[0056] The system may also include other components, preferably selected from:

[0057] c. Fixation devices, such as rigid felt, CFRC-, Al2O3, BN, or metal rings or bandages;

[0058] d. One or more graphite foils and / or CFRC layers and / or graphite slurry coatings, preferably arranged as a covering layer on one or more surfaces of the fiber composite felt.

[0059] The present invention also relates to a component kit, namely a building block system comprising one or more fiber composite mats of the present invention and fastening devices such as those described above.

[0060] The present invention also relates to a method for producing curved fiber composite felt, preferably according to any claim, the method comprising the following steps:

[0061] (1) A flat sheet of fiber composite felt for high-temperature applications, particularly for high-temperature furnaces, having one or more surfaces, wherein the fiber composite felt comprises:

[0062] The fibrous material is preferably in a nonwoven form and / or based on short fibers;

[0063] Carbon-based matrix materials;

[0064] (2) One or more grooves are machined in one or more flat surfaces of the fiber composite felt to enable the fiber composite felt to bend;

[0065] (3) Bending the fiber composite felt to reduce the free volume of the groove, preferably by means of a bending tool to reduce the strain of the external fibers.

[0066] This bending process can be performed similarly to the Thonet bending process known in wood forming, which dates back to a patent from 1856, in which curvature is introduced into the wood using pre-forming and bending (metal) tools.

[0067] Optional:

[0068] In some embodiments, the above-described method of invention and the method in claim 15 preferably further include an initial step of producing a starting composite felt, preferably in the form of a plate, namely step (0).

[0069] (0) The following materials are mixed, pressed, cured and heat-treated to obtain a fiber composite felt, preferably in the form of a flat sheet:

[0070] a. Fiber materials, preferably comprising rayon, oxidized PAN, phenolic fibers, and / or pitch fibers; and

[0071] b. Adhesive material selected from bitumen or thermosetting resins, preferably phenolic resins, epoxy resins or furan resins, or carbohydrates, especially sugars, starches or cellulose.

[0072] For rayon, oxidized PAN, phenolic fiber, and / or pitch-based fiber materials, step (0) is typically performed in a stepwise manner. In a first sub-step, carbon fiber felt is produced by carbonizing and graphitizing the rayon, oxidized PAN, phenolic fiber, and / or pitch-based fiber material felt in an inert gas atmosphere. Subsequently, the felt is impregnated with a liquid resin, laminated, pressed, and cured, and then carbonized and graphitized again in an inert gas atmosphere.

[0073] Alternatively, the rayon fibers can be carbonized, the product ground, then mixed with phenolic resin powder, molded, pressed, and finally heat-treated to obtain the composite felt of the present invention.

[0074] The present invention also relates to products that can be obtained by the above-described method and the method specified in claim 15. Detailed Implementation

[0075] Example

[0076] The invention will now be described in more detail with the aid of manufacturing embodiments and accompanying drawings.

[0077] Manufacturing Examples

[0078] A rigid felt board measuring 1600 mm (length), 1300 mm (width), and 40 mm (height = thickness) is made of a blend of phenolic resin and carbon fiber. The fiber material is pressed with an adhesive and then subjected to high-temperature treatment at temperatures up to 3000°C to shape, cure, carbonize, and graphitize the material. The board is then pre-processed to the following dimensions: length: 500 mm, width: 320 mm, height: 30 mm.

[0079] Using a wedge milling cutter, multiple grooves are introduced into one of the two flat surfaces of the plate, such as... Figures 1 to 2As shown in a) and b). These grooves are evenly spaced along the flat surface, with each groove extending from one side surface to the other. The cut height, i.e., the groove height, exceeds the total height T of the plate. f 85%. Due to the wedge-shaped cut, the groove width decreases downwards until the sidewalls of the groove contact ( Figure 2 Detail X in a). A double-wedge-shaped, interlocking connecting device is machined into the side surface of the slender end of the sheet metal. Figure 2 Details Y and Z in a).

[0080] The plate can now be bent along the flat surface in which the grooves have been introduced to obtain a hollow cylinder. This almost completely closes the free volume between the wedge-shaped sidewalls. To achieve a complete cylinder, two such segments can be used ( Figure 4 Two semi-cylinders are connected to each other, their opposing side surfaces can now contact each other, and the closed hollow cylinder can be stabilized by two rigid felt rings, located on the two end surfaces of the hollow cylinder, respectively, as shown. Figure 5 As shown. Attached Figure Description

[0081] Figure 1 A perspective view of the flat hard felt board of the present invention is depicted, the board having a plurality of grooves equidistantly arranged along the upper flat surface, and having a double V-shaped connecting device with a shape fit machined on the side surface.

[0082] Figure 2 a) and b) describe Figure 1 The present invention provides a side view and a top view of a flat hard felt board having a plurality of grooves equidistantly arranged along an upper flat surface.

[0083] Figure 3 a) Depicts a curve with 180° Figure 1 and Figure 2 The stiff felt shown in a) and b) Figure 3 b) The magnified view shows the connection concept of the double V-shaped connection device with shape matching.

[0084] Figure 4 Depicting two pieces such as... Figure 1 and Figure 2 Top views of the hollow cylinder obtained by bending the rigid felt board shown in a) and b).

[0085] Figure 5 A perspective view of the fiber composite felt of the present invention, in the form of a hollow cylinder, is depicted, the fiber composite felt being secured by two rigid felt rings. Figure 4 It is obtained through the structure.

[0086] Figure 6 Depicting Figure 3 The curved stiff felt board is a perspective view. Figure 5 The semi-cylindrical segment of a hollow cylinder.

[0087] Figure 7 Depicting Figure 3 The rigid felt, in which a curved hollow cylindrical section is stabilized within the structure by means of two rigid felt rings as fixing devices. Attached Figure Description

[0088] Figure 1-2 A rigid felt board 1 according to the present invention is described. This board, which can be obtained according to the manufacturing embodiments described above, includes wedge-shaped grooves 3 evenly arranged along its upper surface to form a board segment with a width of S. w 6. Independent segments 2. These segments can be bent along the line of the thinning hinged region 12. The height of the groove exceeds 85% of the total height (=thickness) of the plate. Figure 3 a) shows the plate bent into a 180° semi-cylinder. Figure 3 b) The magnified view shows the connection concept of the double V-shaped connection device with shape matching.

[0089] Figure 4 The cylindrical felt body 8 is shown, which consists of two pieces such as Figure 1 and Figure 2 The rigid felt plate depicted in a) and b) is obtained by bending. It can be seen that, due to the bending, the free space between the wedge-shaped sidewalls is almost completely closed. This is achieved by contacting and connecting the connecting elements 4 arranged on the side surfaces. Figure 3 a) and b) can connect two curved stiff felts and stabilize the structure.

[0090] Figure 5 A perspective view of the fiber composite felt of the present invention is depicted. The hollow cylinder consists of two hollow cylindrical segment components and two fixing devices (i.e., rigid felt rings 13). Figure 1 The image shows one of two identical semi-cylindrical segments lying flat. Figure 3 The bending state is shown in a and 6. These longitudinal plates include a flat bottom surface with grooves arranged therein and a flat top surface without grooves. Figure 6 As shown, the flat top surface serves as the outer surface in the curved position. The plate includes two stepped shoulders, the height of which decreases partially along the longitudinal axis. These stepped shoulders secure the curved cylindrical segment to the ring 13, resulting in a structure where the ring 13 is flush with the outer flat surface of the composite felt, as shown. Figure 5 and 7 As shown. A hollow cylinder can be constructed using one or more such curved composite felts, such as... Figure 5 As shown in the example.

[0091] Figure Labels

[0092] 1. Sheet-shaped fiber composite felt

[0093] 2. Plate segments arranged between the grooves

[0094] 3 grooves

[0095] 4. Connecting elements of the connecting device

[0096] 5. Thickness T of flat composite felt f

[0097] 6. Width S of the plate segment w

[0098] 7. The length P of the plate L

[0099] 8 Hollow cylindrical fiber composite felt

[0100] 9 inner diameter D I

[0101] 10 Outer diameter D O

[0102] 11 Contact connection elements

[0103] 12. Hinge section

[0104] 13. Hard felt ring as a fixing device

[0105] 14 Semi-hollow cylindrical fiber composite felt

Claims

1. A fiber composite felt for high-temperature applications, particularly for high-temperature furnaces, having one or more surfaces, wherein the fiber composite felt comprises Fiber materials, preferably in nonwoven form and / or based on short fibers, Carbon-based matrix materials Its features are, The fiber composite felt includes one or more grooves for enabling the fiber composite felt to be bent.

2. The fiber composite felt according to claim 1, wherein the fiber material is selected from carbon fiber, particularly graphite fiber and SiC fiber; particularly carbon fiber or graphite fiber produced from rayon precursor, PAN oxide precursor, phenolic fiber precursor and / or pitch precursor.

3. The fiber composite felt according to any one of the preceding claims, wherein the fiber length L of the fiber material is in the range of 0.1 mm to <20 mm or in the range of 20 mm to 100 mm.

4. The fiber composite felt according to any one of the preceding claims, wherein the fiber composite felt is in the form of a board having two flat surfaces and four side surfaces; and wherein the one or more grooves are arranged in at least one of the two flat surfaces.

5. The fiber composite felt according to claim 4, wherein the thickness T of the board is... f Within the range of 10 mm to 200 mm.

6. The fiber composite felt according to claims 1-5, wherein the fiber composite felt comprises two side surfaces having one or more interlocking connecting devices, the interlocking connecting devices preferably being in the form of interlocking finger-shaped or double-wedge-shaped joints.

7. The fiber composite felt according to any one of the preceding claims, wherein the one or more grooves are wedge-shaped.

8. The fiber composite felt according to any one of the preceding claims, wherein the fiber composite felt comprises three or more grooves on one of its one or more surfaces, and wherein the grooves are preferably arranged at equal intervals.

9. A fiber composite felt comprising one or more fiber composite felts as described in any of the preceding claims, wherein the fiber composite felt has a hollow cylindrical form, the hollow cylinder having an inner diameter of D. I The outer diameter is D O .

10. The fiber composite felt according to claim 9, wherein... The ratio ranges from 0.3 to 0.

95.

11. The fiber composite felt according to claim 9 or 10, wherein D I The range is from 200 mm to 1250 mm.

12. The fiber composite felt according to any one of claims 9-11, wherein the hollow cylinder is obtained by bending and joining the plate-shaped fiber composite felt according to claims 4-8 such that at least two opposing side surfaces come into contact, and by fixing the structure with a fixing device such as a rigid felt or a CFRC ring.

13. The fiber composite felt according to any one of claims 9-12, wherein the fiber material has a fiber orientation that is tangent to the circumference at four points equidistantly distributed along the circumference of the hollow cylinder, wherein the distance along the circumference of the equidistantly distributed points is preferably 0.1-0.25 times the circumference.

14. The fiber composite felt according to any one of claims 9-13, wherein the fiber composite felt has a thermal conductivity of up to 1.5 W / (m·K), preferably up to 0.8 W / (m·K), when measured at 2000°C according to DIN 51936.

15. A high-temperature furnace comprising a fiber composite felt according to any one of claims 1-8 or a fiber composite felt body according to any one of claims 9-14, preferably as a lining.

16. A method for producing curved fiber composite felt, comprising the following steps: (1) A fiber composite felt for high-temperature applications, particularly for high-temperature furnaces, having one or more surfaces, wherein the fiber composite felt comprises: The fibrous material is preferably in a nonwoven form and / or based on short fibers; Carbon-based matrix materials; (2) One or more grooves are machined in one or more flat surfaces of the fiber composite felt to enable the fiber composite felt to bend; (3) Bending fiber composite felt, preferably bending fiber composite felt with the aid of bending tools.

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