Drum type friction plate with long fiber woven structure and preparation method

Abstract

The invention discloses a drum type friction plate with a long fiber woven structure and a preparation method. A continuous net-shaped fiber reinforced material is added in the preparation process of the drum-type friction plate, the continuous net-shaped fiber reinforced material is fiber woven cloth which is woven by using a continuous fiber material and has a net-shaped structure, and the structure depends on a common packaging technology of the drum-type friction plate. The preparation method comprises the following steps: alternately paving fiber woven cloth with a net-shaped structure and a friction material premix on a thin film material, folding a thin film to wrap the friction material premix and the fiber woven cloth, performing hot melting to form a closed material bag wrapping all materials, and performing hot press molding on the material bag to obtain a product, namely the drum-type friction plate with a net-shaped structure reinforcing effect. The drum-type friction plate with the long fiber woven structure has extremely high mechanical strength, the overall structural performance of a drum-type friction plate product can be guaranteed, and the drum-type friction plate product is not prone to cracking and chipping under the violent impact and harsh working conditions.

Description

Technical Field

[0001] The present application relates to the technical field of drum friction plates, and in particular to a drum friction plate with a long fiber braided structure and a preparation method thereof. Background Art

[0002] Friction pads are a key safety component of the automobile braking system and play a decisive role in the braking effect. Drum friction pads are the most commonly used friction pads for vehicles. During use, due to heavy loads, high-speed braking and poor road conditions, friction pads often crack. This phenomenon is particularly obvious at corners and rivet holes. Although the impact and bending strength of materials are usually considered during the design process of drum friction pad products, for example, fiber-reinforced materials such as glass fiber, aramid fiber, carbon fiber and other materials are added during the preparation of friction pads, the fiber-reinforced materials commonly used in the prior art are all chopped fibers, and most of the fiber lengths are less than 5 mm. Although such chopped fiber materials can also increase the strength of drum friction pads, they have a poor effect on the overall strength enhancement of the friction pads, especially the enhancement effect on special areas is not targeted.

[0003] Some researchers in the prior art have also tried to use long fiber reinforced materials to prepare friction plate products, but the long fibers are not easy to disperse in the friction plate products and do not have a fixed fiber arrangement, so the reinforcement effect of such long fiber friction plate products is poor.

[0004] Therefore, it is urgent to develop a preparation process for a friction plate with higher strength to solve the problems of the existing technology. Summary of the invention

[0005] In view of this, the purpose of the present application is to provide a drum friction plate with a long fiber woven structure and a preparation method thereof. A continuous mesh fiber reinforcement material is added to the drum friction plate during the preparation process. The continuous mesh fiber reinforcement material is a fiber woven cloth with a mesh morphological structure woven using continuous fiber material. The structure relies on the bagging process commonly used in drum friction plates. The mesh morphological structure fiber woven cloth and the friction material premix are alternately laid flat on the film material, and then the film is folded to wrap the friction material premix and the fiber woven cloth, and hot-melted to form a closed material bag covering all materials. The material bag is hot-pressed to form a product, that is, a drum friction plate with a mesh structure reinforcement effect.

[0006] In order to achieve or at least partially achieve the above objectives, the present application provides the following technical solutions:

[0007] In a first aspect, the present application provides a method for preparing a drum friction plate having a long fiber braided structure, comprising the following steps:

[0008] The first step is to prepare continuous fiber materials;

[0009] The second step is to weave the continuous fiber material to form a fiber woven cloth with a grid structure;

[0010] The third step is to mix the friction materials to form a friction material premix; the friction material comprises phenolic resin, nitrile rubber powder, antimony sulfide, synthetic graphite, calcium sulfate whisker, light calcium carbonate, zircon powder, precipitated barium sulfate, vermiculite, and basalt wool;

[0011] The fourth step is to alternately lay the friction material premix and the fiber woven cloth on the surface of the film in sequence, wherein the number of layers of the fiber woven cloth is 1 to 3, and the fiber woven cloth is located between the friction material premix; after the laying is completed, the film is folded to wrap the friction material premix and the fiber woven cloth, and hot-melt to form a closed material bag covering all materials;

[0012] The fifth step is to hot-press the material package formed in the fourth step, and cut it to obtain a drum-type friction plate with a long-fiber woven structure.

[0013] Furthermore, in the first step, the diameter of the single fiber of the continuous fiber material is 0.5-50 μm, the formed fiber bundle has 1000-24000 single fibers / bundle, and the fiber denier is 100-3000D.

[0014] Further, in the first step, the continuous fiber material includes at least one of continuous long fibers or fiber materials formed by twisting short fibers.

[0015] Furthermore, the continuous long fibers include at least one of alkali-free glass fibers, continuous carbon fibers, and aramid fibers (long fibers).

[0016] Furthermore, in the first step, the short fibers include at least one of cellulose fibers and aramid fibers (short fibers).

[0017] Furthermore, in the second step, the fiber woven cloth has a square grid structure woven at ±90° or a regular triangle grid structure woven at 0 / 60° / 120°, and the grid size has a side length of 5 to 25 mm.

[0018] Furthermore, in the third step, the components of the friction material are calculated by mass fraction as follows: 6% to 15% phenolic resin, 3% to 10% nitrile rubber powder, 3% to 8% antimony sulfide, 10% to 30% synthetic graphite, 3% to 8% calcium sulfate whiskers, 10% to 25% light calcium carbonate, 3% to 8% zircon powder, 10% to 20% precipitated barium sulfate, 3% to 8% vermiculite, and 3% to 8% basalt wool.

[0019] Furthermore, in the fourth step, the material of the film is any one of polypropylene (PP), polyethylene (PE), and polyvinyl alcohol (PVA), and the thickness of the film is 0.02 to 0.05 mm.

[0020] Furthermore, in the fourth step, the paving thickness of each layer of the friction material premix is ​​3 to 5 mm.

[0021] In a second aspect, the present application provides a drum-type friction plate with a long-fiber braided structure, which is prepared by the aforementioned method.

[0022] The present application provides a drum-type friction plate with a long fiber braided structure and a preparation method thereof, which, compared with the prior art, has at least the following beneficial effects:

[0023] 1. The drum-type friction plate with a long fiber braided structure provided in the present application has extremely high mechanical strength, which can ensure the overall structural performance of the product and is not prone to cracking or falling off when the product is subjected to severe impact or harsh working conditions.

[0024] 2. The drum-type friction plate with a long fiber woven structure provided in the present application has strong designability. During the preparation process of the drum-type friction plate, a fiber woven cloth with a mesh structure woven with continuous fiber material is added. Relying on the bagging process commonly used in drum-type friction plates, the alternatingly laid friction material premix and fiber woven cloth are wrapped with a film material, and hot-melt to form a closed material bag that covers all materials. According to actual needs, different combinations of friction materials and fiber woven cloths can be configured in the bottom layer area, middle layer area, and surface layer area of ​​the friction plate, respectively, to achieve differential fiber reinforcement effects in different areas, and can selectively enhance one or more mechanical properties of the friction plate material such as shear and stretching, taking into account both the performance and production cost of the friction plate.

[0025] 3. Certain drum-type friction plates with long fiber braided structures provided in the present application have the mixed advantages of compound fibers. In these drum-type friction plates, multiple fiber materials are twisted to obtain composite fibers, thus having the advantages of multiple fiber materials. For example, the twisting of aramid fiber and continuous carbon fiber enables the branched structure of aramid fiber to absorb more powder materials, thereby ensuring the uniformity of friction and wear of the friction plate. At the same time, the carbon fiber can provide strong tensile strength along the fiber direction, thereby ensuring the structural strength of the friction plate product. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structure of a flat drum-type friction plate with a long fiber woven structure in an embodiment of the present application, wherein; 1 is a film, 2 is a friction material premix, and 3 is a fiber woven cloth. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0028] Those skilled in the art will appreciate that, unless otherwise stated, the "said", "the", and "the aforementioned" used in the text of the present application may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present application means the presence of the features, steps, and operations, but does not exclude the presence or addition of one or more other features, integers, and steps.

[0029] In the text of this application, the terms "first", "second" and the like are used to distinguish between identical or similar items with substantially the same functions and effects. This is only for the purpose of clearly describing the technical solutions of the embodiments of this application, and shall not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0030] Based on the existing drum friction plate preparation technology, the embodiment of the present application uses a bagging process to integrate the friction material and the fiber material with a mesh woven structure to form a material bag, and then the material bag is hot-pressed and cut to form a drum friction plate. The prepared drum friction plate has extremely high mechanical strength, which can ensure the overall structural performance of the product, and is not prone to cracking and falling off when the friction plate product is subjected to severe impact and harsh working conditions.

[0031] Based on this, an embodiment of the present application provides a method for preparing a drum friction plate with a long fiber woven structure, comprising the following steps: a first step, preparing a continuous fiber material, wherein the continuous fiber material includes at least one of the fiber materials formed by twisting continuous long fibers or short fibers; a second step, weaving the continuous fiber material at a fixed angle to form a fiber woven cloth with a grid structure; a third step, mixing the friction material to form a friction material premix; the components of the friction material include phenolic resin, nitrile rubber powder, antimony sulfide, synthetic graphite, calcium sulfate whiskers, light calcium carbonate, zircon powder, precipitated barium sulfate, vermiculite, and basalt wool; a fourth step, alternately laying the friction material premix and the fiber woven cloth on the surface of the film in sequence, the number of laid layers of the fiber woven cloth is 1 to 3 layers, and the fiber woven cloth is located between the friction material premix; after the laying is completed, the film is folded to wrap the friction material premix and the fiber woven cloth, and hot-melt to form a closed material bag covering all materials; a fifth step, hot-pressing the material bag formed in the fourth step, and cutting to obtain a drum friction plate with a long fiber woven structure.

[0032] In the embodiments of the present application, the type of fiber woven cloth in each layer and the type of friction material premix in each layer can be arbitrarily combined. For example, each layer of a plurality of fiber woven cloths can be woven using a different type of continuous fiber material, and each layer of fiber woven cloth can also be woven using one or more continuous fiber materials. The component formulas of each layer of friction material premix can be the same or different, and the flat thickness of each layer of friction material premix can also be limited according to actual needs.

[0033] Figure 1 What is shown is a schematic diagram of the flat structure of a drum-type friction plate prepared in certain embodiments. As can be seen from the figure, the drum-type friction plate comprises three layers of friction material premix 2 and two layers of fiber woven cloth 3.

[0034] In certain embodiments, in the first step, the diameter of the single filament of the continuous fiber material is 0.5-50 μm, the formed fiber bundle has 1000-24000 single filaments / bundle, and the fiber denier is 100-3000D.

[0035] In certain embodiments, in the first step, the continuous long fibers include at least one of alkali-free glass fibers and continuous carbon fibers.

[0036] In some embodiments, in the first step, the short fibers include at least one of cellulose fibers and aramid fibers.

[0037] In some embodiments, in the second step, the fiber woven cloth has a square grid structure woven at ±90° or a regular triangle grid structure woven at 0 / 60° / 120°, and the grid size has a side length of 5 to 25 mm.

[0038] In some embodiments, in the third step, the components of the friction material are, by mass fraction, 6% to 15% phenolic resin, 3% to 10% nitrile rubber powder, 3% to 8% antimony sulfide, 10% to 30% synthetic graphite, 3% to 8% calcium sulfate whiskers, 10% to 25% light calcium carbonate, 3% to 8% zircon powder, 10% to 20% precipitated barium sulfate, 3% to 8% vermiculite, and 3% to 8% basalt wool.

[0039] In some embodiments, in the fourth step, the material of the film is any one of polypropylene (PP), polyethylene (PE), and polyvinyl alcohol (PVA), and the thickness of the film is 0.02 to 0.05 mm.

[0040] In certain embodiments, in the fourth step, the paving thickness of each layer of the friction material premix is ​​3-5 mm.

[0041] In some embodiments, in the fifth step, the hot pressing molding process includes: placing the material bag obtained in the fourth step into a hot pressing mold, using an upper mold temperature of 160±10°C, a lower mold temperature of 145±10°C, and a molding pressure of 150kg / cm 2 , take it out after static pressing for 10 to 20 minutes, and heat treat it at 160 to 180°C for 8 to 12 hours.

[0042] In certain embodiments, in the fifth step, in the drum-type friction plate obtained by the hot pressing, the flat thickness of the premix is ​​reduced to 2-3 mm.

[0043] Based on this, an embodiment of the present application also provides a drum friction plate, which is prepared by the aforementioned preparation method.

[0044] The technical solution of the present application and the technical effects achieved are described in detail below through more specific embodiments.

[0045] Example 1

[0046] This embodiment provides a method for preparing a drum-type friction plate with a long fiber braided structure, and the specific steps include:

[0047] (1) Alkali-free glass fiber and aramid fiber (long fiber) are selected to weave into glass fiber woven cloth and aramid fiber woven cloth respectively, wherein the weaving structure of the glass fiber woven cloth is a square grid structure with a grid side length of 10 mm, and the weaving structure of the aramid fiber woven cloth is a square grid structure with a grid side length of 5 mm;

[0048] (2) Mixing the friction material to form a friction material premix; the friction material comprises phenolic resin, nitrile rubber powder, antimony sulfide, synthetic graphite, calcium sulfate whisker, light calcium carbonate, zircon powder, precipitated barium sulfate, vermiculite, and basalt wool; using PP as the film material, laying the friction material premix and fiber woven cloth on the surface of the film in sequence to form three layers of friction material premix and two layers of fiber woven cloth, wherein the first layer of friction material premix has a thickness of 2.5 mm, the second layer of friction material premix has a thickness of 6 mm, and the third layer of friction material premix has a thickness of 7 mm; the first layer of fiber woven cloth is glass fiber woven cloth, and the second layer of fiber woven cloth is aromatic fiber woven cloth;

[0049] (3) After the flattening is completed, the film is folded to wrap the friction material premix and the fiber woven cloth, and hot-melted to form a closed material bag covering all materials; the formed material bag is put into the hot press mold for hot pressing molding, with the upper mold temperature of 160°C, the lower mold temperature of 145°C, and the molding pressure of 150kg / cm 2 After static pressing for 15 minutes, it was taken out and heat treated at 180°C for 8 hours before being cut into drum friction plates with a long fiber woven structure in a size of 410*220mm.

[0050] Example 2

[0051] This embodiment provides a method for preparing a drum-type friction plate with a long fiber braided structure, and the specific steps include:

[0052] (1) Alkali-free glass fiber and continuous carbon fiber are selected to weave into glass fiber woven cloth and carbon fiber woven cloth respectively, wherein the weaving structure of the glass fiber woven cloth is a square grid structure with a grid side length of 10 mm, and the weaving structure of the carbon fiber woven cloth is a square grid structure with a grid side length of 3.5 mm;

[0053] (2) mixing the friction material to form a friction material premix; the friction material comprises phenolic resin, nitrile rubber powder, antimony sulfide, synthetic graphite, calcium sulfate whisker, light calcium carbonate, zircon powder, precipitated barium sulfate, vermiculite, and basalt wool; using PVA as a film material, laying the friction material premix and fiber woven cloth on the surface of the film in sequence to form three layers of friction material premix and two layers of fiber woven cloth, wherein the first layer of friction material premix has a thickness of 3.5 mm, the second layer of friction material premix has a thickness of 7 mm, and the third layer of friction material premix has a thickness of 8 mm, the first layer of fiber woven cloth is a glass fiber woven cloth, and the second layer of fiber woven cloth is a carbon fiber woven cloth;

[0054] (3) After the flattening is completed, the film is folded to wrap the friction material premix and the fiber woven cloth, and hot-melted to form a closed material bag covering all materials; the formed material bag is put into the hot press mold for hot pressing molding, with the upper mold temperature of 150°C, the lower mold temperature of 135°C, and the molding pressure of 150kg / cm 2 After static pressing for 20 minutes, it was taken out and heat treated at 160°C for 10 hours before being cut into drum friction plates with a long fiber woven structure of 410*220mm in size.

[0055] Comparative Example 1

[0056] This comparative example provides a method for preparing a drum friction plate, and the specific steps thereof include:

[0057] (1) preparing the same glass fiber and aramid fiber as in Example 1, cutting them into short glass fiber and short aramid fiber with a length of 4.5 mm respectively for standby use;

[0058] (2) Mixing the friction material to form a friction material premix; the friction material comprises phenolic resin, nitrile rubber powder, antimony sulfide, synthetic graphite, calcium sulfate whisker, light calcium carbonate, zircon powder, precipitated barium sulfate, vermiculite, and basalt wool; using PP as the film material, laying the friction material premix and chopped fibers (non-woven) on the surface of the film in sequence to form three layers of friction material premix and two layers of fiber woven fabric, wherein the first layer of friction material premix has a thickness of 2.5 mm, the second layer of friction material premix has a thickness of 6 mm, and the third layer of friction material premix has a thickness of 7 mm; the first layer of chopped fiber material is chopped glass fiber material, and the second layer of chopped fiber material is chopped aramid fiber;

[0059] (3) After the flattening is completed, the film is folded to wrap the friction material premix and the chopped fiber material, and hot-melted to form a closed material bag covering all the materials; the formed material bag is put into the hot press mold for hot pressing, with the upper mold temperature of 160°C, the lower mold temperature of 145°C, and the molding pressure of 150kg / cm 2 , taken out after static pressing for 15 minutes, and cut into drum friction plates with a size of 410*220mm after heat treatment at 180℃ for 8 hours.

[0060] Comparative Example 2

[0061] This comparative example provides a method for preparing a drum friction plate, and the specific steps thereof include:

[0062] (1) preparing the same glass fiber and carbon fiber as in Example 2, cutting them into chopped glass fiber and chopped carbon fiber with a length of 4.5 mm respectively, and setting them aside;

[0063] (2) mixing the friction material to form a friction material premix; the friction material comprises phenolic resin, nitrile rubber powder, antimony sulfide, synthetic graphite, calcium sulfate whisker, light calcium carbonate, zircon powder, precipitated barium sulfate, vermiculite, and basalt wool; using PVA as a film material, laying the friction material premix and chopped fiber material (non-woven) on the surface of the film in sequence to form three layers of friction material premix and two layers of fiber woven cloth, wherein the first layer of friction material premix has a thickness of 3.5 mm, the second layer of friction material premix has a thickness of 7 mm, and the third layer of friction material premix has a thickness of 8 mm, the first layer of chopped fiber material is chopped glass fiber, and the second layer of chopped fiber material is chopped carbon fiber;

[0064] (3) After the flattening is completed, the film is folded to wrap the friction material premix and the chopped fiber material, and hot-melted to form a closed material bag covering all the materials; the formed material bag is put into the hot press mold for hot pressing molding, with the upper mold temperature of 150°C, the lower mold temperature of 135°C, and the molding pressure of 150kg / cm 2, taken out after static pressing for 20 minutes, and cut into drum friction plates with a size of 410*220mm after heat treatment at 160℃ for 10 hours.

[0065] In the drum friction plates prepared in Examples 1 and 2 and Comparative Examples 1 and 2, the components of the friction material and the fiber material, measured by mass fraction, are shown in Table 1 below:

[0066] Table 1

[0067] Component (%) Example 1 Example 2 Comparative Example 1 Comparative Example 2 Phenolic resin 12 8 12 8 Nitrile rubber powder 4 4 4 4 Antimony sulfide 4 7 4 7 Synthetic graphite 13 20 13 20 Calcium sulfate whiskers 5 3 5 3 Light calcium carbonate 15 20 15 20 Zircon powder 5 5 5 5 Precipitated barium sulfate 18 15 18 15 Vermiculite 6 5 6 5 Basalt wool 6 5 6 5 Fiberglass Woven Cloth 8 5 0 0 Carbon fiber woven cloth 0 3 0 0 Aramid woven fabric 4 0 0 0 Chopped Glass Fiber 0 0 8 5 Chopped Aramid Fiber 0 0 4 0 Chopped Carbon Fiber 0 0 0 3 total 100 100 100 100

[0068] The drum friction plates prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were tested for mechanical properties such as bending strength, impact strength and compressive strength, with the reference test standards being:

[0069] Bending strength: GB / T 5764-2011 Automobile clutch facing;

[0070] Impact strength: GBT 33835-2017 Friction material impact strength test method;

[0071] Compressive strength: GB / T 1041-2008 Plastics. Determination of compression properties.

[0072] The final mechanical properties test results are shown in Table 2 below:

[0073] Table 2

[0074] Test items Example 1 Example 2 Comparative Example 1 Comparative Example 2 Bending strength / Mpa 51.9 59.8 31.6 41.7 <![CDATA[Impact strength / J / cm 2 > 0.619 0.772 0.428 0.409 Compressive strength / Mpa 114.5 90.4 87.6 79.2

[0075] It can be seen from the results in Table 2 that the bending strength, impact strength and compressive strength of the drum friction plate product with a long fiber woven structure prepared in the embodiment are significantly improved compared with the drum friction plate prepared in the comparative example. This is because in the drum friction plate preparation method in the embodiment, the fibers are woven so that the originally disordered fibers have a specific structural arrangement, and the woven fiber structure has better overall performance under stress, is more conducive to force dispersion, avoids stress concentration, and thus greatly improves the mechanical properties of the product.

[0076] The present application is described in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the present application and its core ideas. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A method for preparing a drum friction plate with a long fiber braided structure, characterized in that: The following steps are involved: The first step is to prepare continuous fiber materials; The second step is to weave the continuous fiber material to form a fiber woven cloth with a grid structure; The third step is to mix the friction materials to form a friction material premix; the friction material comprises phenolic resin, nitrile rubber powder, antimony sulfide, synthetic graphite, calcium sulfate whisker, light calcium carbonate, zircon powder, precipitated barium sulfate, vermiculite, and basalt wool; The fourth step is to alternately lay the friction material premix and the fiber woven cloth on the surface of the film in sequence, wherein the number of layers of the fiber woven cloth is 1 to 3, and the fiber woven cloth is located between the friction material premix; after the laying is completed, the film is folded to wrap the friction material premix and the fiber woven cloth, and hot-melt to form a closed material bag covering all materials; The fifth step is to hot-press the material package formed in the fourth step, and cut it to obtain a drum-type friction plate with a long-fiber woven structure.

2. The preparation method according to claim 1, characterized in that: In the first step, the diameter of the single fiber of the continuous fiber material is 0.5-50 μm, the formed fiber bundle has 1000-24000 single fibers / bundle, and the fiber denier is 100-3000D.

3. The preparation method according to claim 1, characterized in that: In the first step, the continuous fibers include at least one of alkali-free glass fibers, continuous carbon fibers, and medium-length fibers of aramid fibers.

4. The preparation method according to claim 1, characterized in that: In the first step, the continuous fibers are formed by twisting at least one short fiber selected from cellulose fibers and aramid fibers.

5. The preparation method according to claim 1, characterized in that: In the second step, the fiber woven cloth has a square grid structure woven at ±90° or a regular triangle grid structure woven at 0 / 60° / 120°, and the grid side length is 5 to 25 mm.

6. The preparation method according to claim 1, characterized in that: In the third step, the components of the friction material are calculated by mass fraction as follows: 6% to 15% phenolic resin, 3% to 10% nitrile rubber powder, 3% to 8% antimony sulfide, 10% to 30% synthetic graphite, 3% to 8% calcium sulfate whisker, 10% to 25% light calcium carbonate, 3% to 8% zircon powder, 10% to 20% precipitated barium sulfate, 3% to 8% vermiculite, and 3% to 8% basalt wool.

7. The preparation method according to claim 1, characterized in that: In the fourth step, the material of the film is any one of polypropylene, polyethylene, and polyvinyl alcohol, and the thickness of the film is 0.02-0.05 mm.

8. The preparation method according to claim 1, characterized in that: In the fourth step, the paving thickness of each layer of the friction material premix is ​​3 to 5 mm.

9. The preparation method according to claim 1, characterized in that: In the fifth step, the hot pressing molding process includes: putting the material package obtained in the fourth step into the hot pressing machine mold, using the upper mold temperature of 160±10℃, the lower mold temperature of 145±10℃, and the molding pressure of 150kg / cm 2 , take it out after static pressing for 10 to 20 minutes, and heat treat it at 160 to 180°C for 8 to 12 hours.

10. A drum friction plate with a long fiber braided structure, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 9.

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