Composite friction powder for preparing brake pad, composite friction material and brake lining

Abstract

The invention relates to the technical field of preparation of brake pads, in particular to composite friction powder, a composite friction material and a brake lining for preparing the brake pads. The invention discloses composite friction powder for preparing a brake pad. The composite friction powder comprises the following components in parts by mass: 40-80 parts of liquid cardanol phenolic resin, 10-45 parts of inorganic filler and 5-20 parts of a curing agent. In order to solve the problems that an existing friction material is high in abrasion rate and poor in high-temperature braking stability and safety, the composite friction powder for preparing the brake pad and the composite friction material are provided, the yield of brake pad production is increased, the mechanical strength of the composite friction powder is enhanced, and the service life of the brake pad is prolonged. Therefore, the manufactured brake pad has more stable high-temperature friction coefficient and lower wear rate, and the actual service life of the brake pad is greatly prolonged.

Description

Technical Field

[0001] The present application relates to the technical field of brake pad preparation, and more specifically, to a composite friction powder, a composite friction material, and a brake lining for preparing brake pads. Background Art

[0002] In a car's braking system, brake pads are the most critical safety components, typically composed of steel plates, an adhesive insulation layer, and friction blocks. The friction blocks, composed of friction material and adhesive, are pressed against the brake disc or drum during braking, generating friction and thus decelerating the vehicle. During the friction material mixing process, the various materials in the formulation exhibit varying physical and chemical properties. This is primarily reflected in density differences between the filler and other materials, as well as poor compatibility with the binder. This results in some fillers agglomerating and sinking to the bottom. This results in uneven mixing of the friction material components, significantly increasing the defective rate of pressed brake pads. Furthermore, due to friction, the friction blocks gradually wear out, necessitating timely replacement of the brake pads. Otherwise, the steel plates will come into direct contact with the brake disc, ultimately leading to a loss of braking effectiveness and damage to the disc.

[0003] As vehicles evolve towards environmentally friendly, high-speed, and heavy-load driving, higher requirements are being placed on the stability and safety of automotive brake materials during high-temperature braking. Existing friction materials thermally decompose at operating temperatures exceeding 250°C, resulting in a significant decrease in friction coefficient and a high wear rate, seriously impacting driving safety. To meet practical application requirements, ensuring the wear resistance of friction materials in high-temperature environments, controlling wear, and reducing noise have become urgent research challenges. Summary of the Invention

[0004] In order to solve the problems of high wear rate, poor high-temperature braking stability and safety of existing friction materials, the present application provides a composite friction powder, a composite friction material and a brake lining for preparing brake pads.

[0005] In a first aspect, the present application provides a composite friction powder for preparing a brake pad, which adopts the following technical solution: a composite friction powder for preparing a brake pad, comprising the following components in parts by weight: 40-80 parts of liquid cardanol phenolic resin, 10-45 parts of inorganic filler, and 5-20 parts of curing agent; Preferably, the inorganic filler includes one or more of graphite, carbon black, barium sulfate or heavy calcium carbonate.

[0006] By adopting the above technical solution, the cardanol phenolic resin contains a unique structure of benzene rings and long-chain aliphatic groups, which gives it excellent heat resistance, elasticity, toughness, etc., and can maintain high strength and stability under high temperature conditions, thereby enhancing the stability of the friction coefficient. In addition, the long-chain alkyl group of cardanol is a hydrophobic structure with good moisture resistance and low water absorption, which also helps to improve the stability of the brake pad in a humid environment. On this basis, the addition of inorganic fillers to the composite friction powder has significantly improved wear resistance and high temperature resistance compared to directly mixing inorganic fillers into the raw materials for preparing the brake pad. By adding inorganic fillers under the condition of a curing agent, the dispersibility and compatibility of the inorganic fillers in the liquid cardanol phenolic resin can be significantly improved, and the bonding of the inorganic fillers at the interface of the liquid cardanol phenolic resin can be improved. Condition, the inorganic filler is wrapped in the liquid cashew phenolic resin through physical adsorption, surface action and other forces, effectively reducing the density of the inorganic filler and expanding its dispersibility. A more stable three-dimensional network structure composite material is formed based on the liquid cashew phenolic resin chain and the curing agent. The filler is filled in the network structure, which can effectively solve the agglomeration and sedimentation problems of the inorganic filler in the traditional brake pad friction material due to the density difference, increase the hardness and wear resistance of the material, and also improve the high temperature resistance of the material. The curing agent accelerates the cross-linking reaction and synergistically forms a more stable composite material, which improves the yield of the brake pad production and enhances the mechanical strength of the composite friction powder itself, so that the manufactured brake pad has a more stable high-temperature friction coefficient and a lower wear rate, which greatly extends the actual service life of the brake pad.

[0007] The curing agent includes one of urotropine or furfural.

[0008] The mass ratio of the liquid cardanol phenolic resin to furfural is (3-5):1.

[0009] By adopting the above technical solution, a cross-linked network structure is generated by reacting the curing agent with the hydroxyl group or phenolic hydroxyl group of the liquid cardanol phenolic resin. The liquid cardanol phenolic resin and furfural in a certain proportion range have an important regulating effect on the curing efficiency and the mechanical properties of the cured material, so that the curing agent forms a more stable cross-linked network by reacting with the phenolic hydroxyl group, and has better toughness, impact resistance and high-temperature heat resistance than the hexamine curing. Among them, excessive furfural will generate more by-products, and cause the curing speed to be too fast and the pores to increase, affecting the high-temperature resistance of the cured material.

[0010] The composite friction powder further comprises zinc stearate.

[0011] The mass ratio of the liquid cardanol phenolic resin to zinc stearate is 1:(0.05-0.11).

[0012] By adopting the above technical solution, liquid cashew phenolic resin and zinc stearate within a certain proportion range interact with each other in improving the wear resistance and high temperature resistance of brake pads. Among them, liquid cashew phenolic resin provides excellent heat resistance and wear resistance, and the entanglement of long-chain molecules of zinc stearate and liquid cashew phenolic resin is conducive to increasing the density and hardness of the composite friction powder, preventing the sedimentation of the filler, thereby improving the mechanical strength and wear resistance. The composite material of liquid cashew phenolic resin and zinc stearate exhibits a more stable friction coefficient and a lower wear rate, and has the characteristics of low noise and high thermal decomposition temperature, which can avoid the performance degradation of the brake pad material formed by it at high temperature, which helps to improve the service life and braking effect of the brake pad. If the zinc stearate content is too high, it will affect the braking effect of the brake pad, reduce the friction coefficient, and reduce the braking efficiency.

[0013] In a second aspect, the present application provides a composite friction material, which adopts the following technical solution: A composite friction material comprises composite friction powder with a percentage content of 8-15wt% for preparing brake pads.

[0014] The composite friction material also includes the following components in the following percentages: 15-18wt% modified phenolic resin, 2-4wt% potassium feldspar powder, 5-8wt% cryolite powder, 3-5wt% talc powder, 3-5wt% powdered nitrile, 10-14wt% barium sulfate, 4-7wt% ferrotitanium green, 1-3wt% glass fiber, 4-5wt% mineral fiber, and the balance is ceramic fiber.

[0015] By adopting the above technical solution, the toughness and elasticity of the composite friction powder act as a buffer during braking, reducing direct impact between the brake pad and the brake disc. Furthermore, at high temperatures, the friction powder decomposes on the brake pad surface, forming a protective layer that controls wear, enhances the wear resistance of the composite friction material, and reduces noise. Therefore, by adding the composite friction powder to the above ingredients and formulating them in a reasonable ratio to form a composite friction material, the heat and wear resistance of the composite friction material are significantly improved. Modified phenolic resin, as the primary binder, provides excellent high-temperature performance and mechanical properties. Fillers and lubricants such as potassium feldspar powder, cryolite powder, and talc powder enhance the overall strength and wear resistance of the brake pad. High-performance materials such as powdered nitrile, barium sulfate, and ferrotitanium green further enhance the wear and tear resistance of the brake pad. Glass fiber, mineral fiber, and ceramic fiber, as reinforcing fibers, enhance mechanical strength and heat resistance.

[0016] The powdered butyronitrile is molybdenum disulfide modified powdered butyronitrile.

[0017] The preparation method of molybdenum disulfide modified butyronitrile powder includes adding molybdenum disulfide to anhydrous ethanol, heating and stirring in a water bath at 70-80°C for 20-30 minutes, then dissolving hexadecyltrimethylammonium bromide in water and adding the solution, continuing heating and stirring for 18-24 hours, filtering, washing, and vacuum drying at 50°C to obtain modified molybdenum disulfide. Powdered butyronitrile is weighed and placed in an open mill for plasticization and uniformity, and then the modified molybdenum disulfide is added and kneaded for 5-10 minutes. Zinc oxide and stearic acid are then added in sequence and kneaded for 10-15 minutes. Finally, dicumyl peroxide and tetramethylthiuram disulfide are added and kneaded for 5-8 minutes. After standing for 24 hours, the mixture is placed in a flat vulcanizer for vulcanization and discharged to obtain molybdenum disulfide modified butyronitrile powder.

[0018] The mass ratio of the modified molybdenum disulfide to powdered butyronitrile is (0.1-0.4):1.

[0019] Molybdenum disulfide modified powdered nitrile is prepared by conventional preparation process. The powdered nitrile molecular chain itself has a certain elasticity, but after being blended with MoS2 modified by hexadecyltrimethylammonium bromide, the long-chain alkyl of the modified MoS2 penetrates into the nitrile molecular chain and interacts with the active sites such as cyano and double bonds on the powdered nitrile molecular chain to form a bond between the molecular chains, so that the modified MoS2 is more evenly dispersed in the nitrile, making it difficult for MoS2 particles to fall off from the matrix, and can continue to play a wear-resistant role and reduce the wear rate. The composite structure of molybdenum disulfide modified powdered nitrile can also strengthen the bonding between the components in the system, limit the excessive slip of the molecular chain, and achieve better rebound when the external force is removed. Therefore, when the friction material is applied to the brake pad, it plays a buffering role, slowing down the direct impact between the brake pad and the brake disc, and reducing the wear rate. In addition, long-chain modification is conducive to further wrapping other fillers and fibers in the composite material based on the entanglement of molecular chains with modified phenolic resin and friction powder, thereby improving the adhesion of fillers and fibers in the molecular network, thereby alleviating problems such as uneven filler density and sedimentation.

[0020] Preferably, the modified phenolic resin is a tung oil-modified phenolic resin; conventional tung oil-modified phenolic resin can be used to prepare the tung oil-modified phenolic resin of the present application.

[0021] The mass ratio of the composite friction powder to the tung oil-modified phenolic resin is 1:(1.6-1.8).

[0022] By employing the above technical solution, tung oil-modified phenolic resin, when used as a binder in composite friction materials, can better bond fillers such as inorganic fibers and composite friction powder, resulting in a more uniform and stable composite material and improving the overall performance of the composite friction material. Tung oil's long-chain unsaturated fatty acid structure helps form a more uniform and stable bonding interface, reducing thermal decomposition and thermal cracking. Furthermore, during high-temperature friction, the tung oil-modified phenolic resin generates a tar-like substance and forms a stable carbonized film, which effectively reduces contact pressure and wear. This interacts with the composite friction powder within a certain proportion to improve heat and wear resistance, stabilize the friction coefficient, and form a more stable composite friction material, thereby improving the yield rate of brake pad production. However, if the tung oil-modified phenolic resin content is too low, the composite friction material may generate more noise during use, affect the friction layer structure of the composite friction material, and increase the wear rate, leading to large fluctuations in the friction coefficient and affecting the braking performance of the brake pad.

[0023] In a third aspect, the present application provides a brake lining, the raw materials for preparing the brake lining include the above-mentioned composite friction material.

[0024] In summary, this application has the following beneficial effects: 1. Liquid cardanol phenolic resin contains a unique structure of benzene rings and long-chain aliphatic groups, which gives it excellent heat resistance, elasticity, toughness, etc., and it can maintain high strength and stability under high temperature conditions, and can improve the stability of the friction coefficient. On this basis, the addition of inorganic fillers to the composite friction powder has significantly improved wear resistance and high temperature resistance compared to directly mixing inorganic fillers into the raw materials for brake pad preparation. By adding inorganic fillers under the condition of a curing agent, the inorganic fillers are wrapped in the liquid cardanol phenolic resin through physical adsorption, surface action and other forces, effectively reducing the density of the inorganic fillers and expanding their dispersibility, effectively solving the problems of agglomeration and sedimentation of inorganic fillers in traditional brake pad friction materials caused by density differences, increasing the hardness and wear resistance of the material, improving the yield rate of brake pad production, and enhancing the mechanical strength of the composite friction powder itself, so that the brake pads have a more stable high-temperature friction coefficient and a lower wear rate, greatly extending the actual service life of the brake pads.

[0025] 2. Liquid cardanol phenolic resin and zinc stearate within a certain ratio interact with each other in improving the wear resistance and high temperature resistance of brake pads. Liquid cardanol phenolic resin provides excellent heat resistance and wear resistance, and interacts with zinc stearate to increase the density and hardness of the composite friction powder, thereby improving mechanical strength, wear resistance and shear resistance. The composite material of liquid cardanol phenolic resin and zinc stearate exhibits a higher friction coefficient and lower wear rate, as well as low noise and a higher thermal decomposition temperature, which can avoid performance degradation at high temperatures, thereby helping to increase the service life and braking effect of the brake pad. Excessive zinc stearate content will affect the braking effect of the brake pad and reduce braking efficiency.

[0026] 3. Tung oil-modified phenolic resin, as a binder in composite friction materials, can better bond fillers such as inorganic fibers and composite friction powder, resulting in a more uniform and stable composite friction material and improving its overall performance. Its interaction with the composite friction powder within a certain range of proportions improves heat resistance and wear resistance, stabilizes the coefficient of friction, and forms a more stable composite friction material, thereby improving the yield rate of brake pad production. However, too low a content of tung oil-modified phenolic resin may cause the composite friction material to generate more noise during use, affect the friction layer structure of the composite friction material, and increase the wear rate, leading to large fluctuations in the friction coefficient and affecting the braking performance of the brake pad. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the 0-500°C thermogravimetric curves of the composite friction powder in Preparation Example 1 of the present application and the cashew nut shell oil friction powder in Comparative Example 1. DETAILED DESCRIPTION

[0028] The present application is further described in detail below with reference to the embodiments.

[0029] Liquid cardanol phenolic resin was purchased from Changshu Naisu Biomaterial Technology Co., Ltd.; graphite specifications (80-100 mesh): purchased from Lingshou County Jiushun Mineral Products Co., Ltd. The relevant raw materials used in the remaining embodiments and comparative examples are all conventional products that can be purchased on the market.

[0030] Preparation Example 1 50g of liquid cardanol phenolic resin was stirred and mixed with 45g of inorganic filler for 2h, wherein the inorganic filler was graphite. The temperature was raised to 90°C, 5g of hexamethylenetetramine was added, and the mixture was stirred and reacted for 2h. The temperature was then raised to 190°C, and the mixture was stirred and reacted in vacuum at a vacuum pressure of -0.01Mpa for 4h. The mixture was cooled to room temperature and then crushed through a 20-mesh sieve to obtain a composite friction powder.

[0031] Preparation Example 2 80g of liquid cardanol phenolic resin was stirred and mixed with 10g of inorganic filler for 2h, wherein the inorganic filler was graphite. The temperature was raised to 90°C, 10g of hexamethylenetetramine was added, and the mixture was stirred and reacted for 2h. The temperature was then raised to 190°C, and the mixture was stirred and reacted in vacuum at a vacuum pressure of -0.01Mpa for 4h. The mixture was cooled to room temperature and then crushed through a 20-mesh sieve to obtain a composite friction powder.

[0032] Preparation Example 3 50g of liquid cardanol phenolic resin was stirred and mixed with 45g of inorganic filler for 2h, wherein the inorganic filler was graphite, and then 15g of furfural was added, and 5g of 94% concentrated sulfuric acid was added dropwise at 70°C. The temperature was raised to 120°C and stirred for 2h, then the temperature was raised to 210°C, and the mixture was stirred in vacuum at a vacuum pressure of -0.02Mpa for 8h. After cooling to room temperature, the mixture was crushed through a 20-mesh sieve to obtain a composite friction powder.

[0033] Preparation Example 4 50g of liquid cardanol phenolic resin was stirred and mixed with 45g of inorganic filler for 2h. The inorganic filler was barium sulfate and heavy calcium carbonate in a mass ratio of 5:3. Then 15g of furfural was added, and 5g of 94% concentrated sulfuric acid was added dropwise at 70°C. The temperature was raised to 120°C and stirred for 2h. Then the temperature was raised to 210°C. The mixture was stirred in vacuum at a vacuum pressure of -0.02Mpa for 8h. After cooling to room temperature, the mixture was crushed through a 20-mesh sieve to obtain a composite friction powder.

[0034] Preparation Example 5 50g of liquid cardanol phenolic resin was stirred and mixed with 45g of inorganic filler for 2h. The inorganic filler was graphite, barium sulfate and heavy calcium carbonate in a mass ratio of 2:5:1. Then 15g of furfural was added, and 5g of 94% concentrated sulfuric acid was added dropwise at 70°C. The temperature was raised to 120°C and stirred for 2h. Then the temperature was raised to 210°C. The mixture was stirred in vacuum at a vacuum pressure of -0.02Mpa for 8h. After cooling to room temperature, the mixture was crushed through a 20-mesh sieve to obtain a composite friction powder.

[0035] Preparation Example 6 50g of liquid cardanol phenolic resin was stirred and mixed with 45g of inorganic filler for 2h. The inorganic filler was graphite, barium sulfate and heavy calcium carbonate in a mass ratio of 2:5:1. Then 10g of furfural was added, and 5g of 94% concentrated sulfuric acid was added dropwise at 70°C. The temperature was raised to 120°C and stirred for 2h. Then the temperature was raised to 210°C. The mixture was stirred in vacuum at a vacuum pressure of -0.02Mpa for 8h. After cooling to room temperature, the mixture was crushed through a 20-mesh sieve to obtain a composite friction powder.

[0036] Preparation Example 7 50g of liquid cardanol phenolic resin was stirred and mixed with 45g of inorganic filler for 2h. The inorganic filler was graphite, barium sulfate and heavy calcium carbonate in a mass ratio of 2:5:1. Then 18g of furfural was added, and 2g of 94% concentrated sulfuric acid was added dropwise at 70°C. The temperature was raised to 120°C and stirred for 2h. Then the temperature was raised to 210°C. The mixture was stirred in vacuum at a vacuum pressure of -0.02Mpa for 8h. After cooling to room temperature, the mixture was crushed through a 20-mesh sieve to obtain a composite friction powder.

[0037] Preparation Example 8 50g of liquid cardanol phenolic resin, 45g of inorganic filler and 2.5g of zinc stearate were stirred and mixed for 2h. The inorganic filler was graphite, barium sulfate and heavy calcium carbonate with a mass ratio of 2:5:1. Then 15g of furfural was added, and 5g of 94% concentrated sulfuric acid was added dropwise at 70°C. The temperature was raised to 120°C and stirred for 2h. Then the temperature was raised to 210°C. The mixture was stirred in vacuum at a vacuum pressure of -0.02Mpa for 8h. After cooling to room temperature, the mixture was crushed through a 20-mesh sieve to obtain a composite friction powder.

[0038] Preparation Example 9 50g of liquid cardanol phenolic resin, 45g of inorganic filler and 5.5g of zinc stearate were stirred and mixed for 2h. The inorganic filler was graphite, barium sulfate and heavy calcium carbonate in a mass ratio of 2:5:1. Then 15g of furfural was added, and 5g of 94% concentrated sulfuric acid was added dropwise at 70°C. The temperature was raised to 120°C and stirred for 2h. Then the temperature was raised to 210°C. The mixture was stirred and reacted in vacuum at a vacuum pressure of -0.02Mpa for 8h. After cooling to room temperature, the mixture was crushed through a 20-mesh sieve to obtain a composite friction powder.

[0039] Preparation Example 10 50g of liquid cardanol phenolic resin, 45g of inorganic filler and 8g of zinc stearate were stirred and mixed for 2h. The inorganic filler was graphite, barium sulfate and heavy calcium carbonate in a mass ratio of 2:5:1. Then 15g of furfural was added, and 5g of 94% concentrated sulfuric acid was added dropwise at 70°C. The temperature was raised to 120°C and stirred for 2h. Then the temperature was raised to 210°C. After stirring and reacting for 8h under a vacuum pressure of -0.02Mpa, the mixture was cooled to room temperature and crushed through a 20-mesh sieve to obtain a composite friction powder.

[0040] Preparation Example 11 100g of phenol, 40g of tung oil, and 0.4g of a 50% aqueous solution of p-toluenesulfonic acid were added to a reaction kettle equipped with a stirrer, a thermometer, and a reflux condenser. The mixture was heated to 100°C with stirring, reacted for 45 minutes, cooled to 50°C, and neutralized by adding an aqueous base solution equivalent to the p-toluenesulfonic acid. Subsequently, 100g of a 37% aqueous solution of formaldehyde and 2.7g of a 37% aqueous solution of sodium hydroxide were added to the reaction system, the pH was adjusted to 8, and the mixture was reacted at 90°C with stirring for 70 minutes. The mixture was cooled to 50°C, and 10% hydrochloric acid was added to neutralize the mixture, adjusting the pH to 7. The mixture was then dehydrated under reduced pressure at 0.02 MPa to obtain a tung oil-modified phenolic resin.

[0041] Preparation Example 12 The preparation method of molybdenum disulfide modified butyronitrile powder includes the following steps: adding 18g of molybdenum disulfide to 200ml of anhydrous ethanol, heating in a water bath at 80°C with stirring for 20min, then dissolving 22g of hexadecyltrimethylammonium bromide in 100g of water and adding the solution, continuing heating and stirring for 24h, filtering, washing, and vacuum drying at 50°C to obtain modified molybdenum disulfide; weighing 10g of butyronitrile powder and putting it into an open mill for plasticization and uniformity, then adding 3g of modified molybdenum disulfide and mixing for 10min, then adding 0.05g of zinc oxide and 0.07g of stearic acid in sequence and continuing mixing for 10min, finally adding 0.04g of diisopropylbenzene peroxide and 0.06g of tetramethylthiuram disulfide, mixing for 8min, standing for 24h, putting it into a flat vulcanizer for vulcanization, and discharging to obtain molybdenum disulfide modified butyronitrile powder.

[0042] Preparation Example 13 The preparation method of molybdenum disulfide modified butyronitrile powder includes the following steps: adding 18g of molybdenum disulfide to 200ml of anhydrous ethanol, heating in a water bath at 80°C with stirring for 20min, subsequently dissolving 22g of hexadecyltrimethylammonium bromide in 100g of water and adding the solution, continuously heating and stirring for 24h, filtering, washing, and vacuum drying at 50°C to obtain modified molybdenum disulfide; weighing 10g of butyronitrile powder, placing it in an open mill for plasticization and uniformity, adding 5g of modified molybdenum disulfide and mixing for 10min, then sequentially adding 0.05g of zinc oxide and 0.07g of stearic acid, continuing to mix for 10min, and finally adding 0.04g of diisopropylbenzene peroxide and 0.06g of tetramethylthiuram disulfide, mixing for 8min, standing for 24h, placing it in a flat vulcanizer for vulcanization, and discharging to obtain molybdenum disulfide modified butyronitrile powder.

[0043] Preparation Example 14 The preparation method of molybdenum disulfide modified butyronitrile powder includes the following steps: weighing 10g of butyronitrile powder, putting it into an open mill and plasticizing it evenly, then adding 3g of molybdenum disulfide and mixing it for 10 minutes, then adding 0.05g of zinc oxide and 0.07g of stearic acid in sequence, continuing to mix it for 10 minutes, and finally adding 0.04g of dicumyl peroxide and 0.06g of tetramethylthiuram disulfide, mixing it for 8 minutes, standing it for 24 hours, and then putting it into a flat vulcanizer for vulcanization, discharging it, and obtaining the molybdenum disulfide modified butyronitrile powder.

[0044] Example 1 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of powdered nitrile, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. The material also includes 9.5g of the composite friction powder prepared in Preparation Example 1, and ceramic fiber is added to make up the total amount to 100g. The modified phenolic resin is the tung oil-modified phenolic resin prepared in Preparation Example 11.

[0045] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0046] Example 2 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of powdered nitrile, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. The material also includes 9.5g of the composite friction powder prepared in Preparation Example 2, and ceramic fiber is added to make up the total weight to 100g. The modified phenolic resin is the tung oil-modified phenolic resin prepared in Preparation Example 11.

[0047] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0048] Example 3 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of powdered nitrile, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. The material also includes 9.5g of the composite friction powder prepared in Preparation Example 3, and ceramic fiber is added to make up the total weight to 100g. The modified phenolic resin is the tung oil-modified phenolic resin prepared in Preparation Example 11.

[0049] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0050] Example 4 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of powdered nitrile, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. The material also includes 9.5g of the composite friction powder prepared in Preparation Example 4, and ceramic fiber is added to make up the total weight to 100g. The modified phenolic resin is the tung oil-modified phenolic resin prepared in Preparation Example 11.

[0051] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0052] Example 5 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of powdered nitrile, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. The material also includes 9.5g of the composite friction powder prepared in Preparation Example 5, and ceramic fiber is added to make up the total weight to 100g. The modified phenolic resin is the tung oil-modified phenolic resin prepared in Preparation Example 11.

[0053] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0054] Example 6 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of powdered nitrile, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. The material also includes 9.5g of the composite friction powder prepared in Preparation Example 6, and ceramic fiber is added to make up the total amount to 100g. The modified phenolic resin is the tung oil-modified phenolic resin prepared in Preparation Example 11.

[0055] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0056] Example 7 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of powdered nitrile, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. The material also includes 9.5g of the composite friction powder prepared in Preparation Example 7, and ceramic fiber is added to make up the total weight to 100g. The modified phenolic resin is the tung oil-modified phenolic resin prepared in Preparation Example 11.

[0057] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0058] Example 8 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of powdered nitrile, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. The material also includes 9.5g of the composite friction powder prepared in Preparation Example 8, and ceramic fiber is added to make up the total weight to 100g. The modified phenolic resin is the tung oil-modified phenolic resin prepared in Preparation Example 11.

[0059] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0060] Example 9 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of powdered nitrile, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. The material also includes 9.5g of the composite friction powder prepared in Preparation Example 9, and ceramic fiber is added to make up the total amount to 100g. The modified phenolic resin is the tung oil-modified phenolic resin prepared in Preparation Example 11.

[0061] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0062] Example 10 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of powdered nitrile, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. The material also includes 9.5g of the composite friction powder prepared in Preparation Example 10, and ceramic fiber is added to make up the total weight to 100g. The modified phenolic resin is the tung oil-modified phenolic resin prepared in Preparation Example 11.

[0063] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0064] Example 11 A composite friction material is made of the following raw materials in percentage by mass: 15g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of powdered nitrile, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. The material also includes 9.5g of the composite friction powder prepared in Preparation Example 5, and ceramic fiber is added to make up the total weight to 100g. The modified phenolic resin is the tung oil-modified phenolic resin prepared in Preparation Example 11.

[0065] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0066] Example 12 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of powdered nitrile, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. It also includes 9.5g of the composite friction powder prepared in Preparation Example 5, and ceramic fiber is added to make up to 100g.

[0067] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0068] Example 13 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of molybdenum disulfide-modified nitrile powder obtained in Preparation Example 12, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. It also includes 9.5g of the composite friction powder obtained in Preparation Example 8, and the ceramic fiber is supplemented to 100g. The modified phenolic resin is the tung oil-modified phenolic resin obtained in Preparation Example 11.

[0069] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0070] Example 14 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of molybdenum disulfide-modified nitrile powder obtained in Preparation Example 13, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. It also includes 9.5g of the composite friction powder obtained in Preparation Example 8, and the ceramic fiber is supplemented to 100g. The modified phenolic resin is the tung oil-modified phenolic resin obtained in Preparation Example 11.

[0071] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0072] Example 15 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of molybdenum disulfide-modified nitrile powder prepared in Preparation Example 14, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. It also includes 9.5g of the composite friction powder prepared in Preparation Example 8, and the ceramic fiber is supplemented to 100g. The modified phenolic resin is the tung oil-modified phenolic resin prepared in Preparation Example 11.

[0073] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0074] Example 16 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 1g of molybdenum disulfide, 3g of powdered nitrile, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. The material also includes 9.5g of the composite friction powder prepared in Preparation Example 8, and ceramic fiber is added to make up the total amount to 100g. The modified phenolic resin is the tung oil-modified phenolic resin prepared in Preparation Example 11.

[0075] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0076] Example 17 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc, 4g of molybdenum disulfide, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, and 14g of mineral fiber. It also includes 9.5g of the composite friction powder prepared in Preparation Example 8, and ceramic fiber is added to make up to 100g. The modified phenolic resin is the tung oil-modified phenolic resin prepared in Preparation Example 11.

[0077] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0078] Comparative Example 1 A composite friction material is made of the following raw materials in percentage by mass: 17.5g of modified phenolic resin, 4g of potassium feldspar powder, 7g of cryolite powder, 4g of talc powder, 4g of powdered nitrile, 13.5g of barium sulfate, 6g of ferrotitanium green, 3g of glass fiber, 14g of mineral fiber, and 9.5g of cashew nut shell oil friction powder, wherein the cashew nut shell oil friction powder comprises liquid cashew phenolic resin and graphite in a mass ratio of 1:0.9, and the ceramic fiber is supplemented to 100g. The modified phenolic resin is the tung oil-modified phenolic resin obtained in Preparation Example 11.

[0079] The above composite friction materials were mixed in proportion using a Loedige mixer for 10 minutes, pressurized at 10 MPa for 20 seconds in a pre-molding mold to obtain a preform, and the preform was hot-pressed and cured in a hot forming mold at a temperature of 165°C and a molding pressure of 30 MPa for 2 hours. After degassing, cooling and demolding, the composite friction material was obtained.

[0080] Performance testing 100 pieces of composite friction material prepared in Examples 1-17 and Comparative Example 1 were synthesized, and those with surface cracks or obvious defects were deemed scrap. The yield rate was calculated. The average yield rate for the Examples exceeded 92%, while the yield rate for the Comparative Example was only 81%. After the brake linings were made, their high-temperature resistance and friction properties were tested using the following methods: According to GB5763-1998 standard, the pressing force is 0.98Mpa, the dual materials are HT250 / and HB196, and the friction coefficient and wear rate of the embodiment and the comparative example are tested at the test temperature of 200℃ and 350℃: unit (10 -7 cm 3 / Nm); Figure 1 The thermogravimetric curves of the composite friction powder prepared in Example 1 of this application and the cashew nut shell oil friction powder of Comparative Example 1 were obtained using a DTG-60H TG / DTA thermogravimetric analyzer produced by Shimadzu, Japan. The test conditions were as follows: heating from room temperature to about 500°C in a nitrogen atmosphere at a heating rate of 15°C min -1 It can be seen intuitively that the comparative example cashew nut shell liquid friction powder has a significant weight loss process at 450°C, corresponding to the decomposition of the main structure, while the composite friction powder prepared in Preparation Example 1 has no significant weight loss process at 500°C. Therefore, the composite friction powder prepared in Preparation Example 1 has higher thermal stability, thereby enhancing the stability of the friction coefficient during high-temperature braking and reducing the wear rate.

[0081] After the examples and comparative examples were used to make brake linings, the friction coefficient and wear rate were tested at different temperatures. The composite friction material made using the composite friction powder of the present application can further improve the stability of the high-temperature friction coefficient of the brake lining, reduce the wear rate, reduce the generation of low-frequency noise, and improve the yield rate.

[0082] Comparing Example 1 and Example 3, it can be seen that the furfural curing system forms a more stable cross-linked network by reacting with phenolic hydroxyl groups and liquid cardanol phenolic resin, and has better impact resistance and high temperature stability than the urotropine curing system.

[0083] From comparative examples 3-7, it can be seen that the inorganic filler graphite, barium sulfate and heavy calcium carbonate in a specific proportion are used in the composite friction powder system of liquid cashew phenolic resin and curing agent to have excellent heat resistance, elasticity and toughness, thereby making the synthesized composite friction material have higher high-temperature braking performance and higher mechanical strength, and reducing the wear rate; among them, the liquid cashew phenolic resin and furfural have an important regulating effect on the mechanical properties and high-temperature resistance of the composite friction powder within a certain proportion range. Excessive furfural will generate more by-products, and lead to too fast curing speed and increased pores, which affect the high-temperature wear resistance of the cured material.

[0084] Comparative Example 8 and Example 13-17 show that the long-chain alkyl of modified MoS2 goes deep into the butyronitrile molecular chain, and interacts with the active sites such as the cyano group, double bonds on the powder butyronitrile molecular chain, forming a bond between molecular chains, making modified MoS2 more uniformly dispersed in butyronitrile, making MoS2 particles difficult to fall off from matrix, and playing a friction-reducing and wear-resistant effect together. This combination also improves the overall toughness of the material, so that the material can better resist the generation and expansion of cracks when subjected to friction stress, thereby improving wear resistance and reducing wear rate.

[0085] Comparative Example 5 and Examples 8-10 show that by adding zinc stearate to the composite friction powder, zinc stearate plays a stabilizing role, increases the density and hardness of the composite friction powder, thereby improving mechanical strength and wear resistance. The composite material of liquid cardanol phenolic resin and zinc stearate exhibits a higher friction coefficient and a lower wear rate, and has low noise and a high thermal decomposition temperature, which can avoid performance degradation at high temperatures and help improve the service life and braking effect of the brake pad. Excessive zinc stearate content reduces the stability of the friction coefficient, affects the braking effect of the brake pad, and reduces braking efficiency.

[0086] By comparing Example 5 with Examples 11-12, it can be seen that the tung oil-modified phenolic resin as a binder in the composite friction material can better bond fillers such as inorganic fibers and composite friction powder, thereby forming a more uniform and stable composite material and improving the overall performance of the composite friction material. The long-chain unsaturated fatty acid structure of tung oil helps to form a more uniform and stable bonding interface, reducing thermal decomposition and thermal cracking. The tung oil-modified phenolic resin and the composite friction powder within a certain proportion range interact with each other to jointly improve the heat resistance and wear resistance, stabilize the friction coefficient, form a more stable composite friction material, and thus improve the yield rate of brake pad production. If the content of tung oil-modified phenolic resin is too low, the composite friction material may generate more noise during use, affect the friction layer structure of the composite friction material, and thus increase the wear rate, resulting in large fluctuations in the friction coefficient, affecting the braking performance of the brake pad.

[0087] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A composite friction powder for preparing brake pads, characterized by: The invention comprises the following components in parts by weight: 40-80 parts of liquid cardanol phenolic resin, 10-45 parts of inorganic filler and 5-20 parts of curing agent.

2. The composite friction powder for preparing brake pads according to claim 1, characterized in that: The curing agent includes one of urotropine or furfural.

3. The composite friction powder for preparing brake pads according to claim 2, characterized in that: The mass ratio of the liquid cardanol phenolic resin to furfural is (3-5):

1.

4. The composite friction powder for preparing brake pads according to claim 1, characterized in that: The composite friction powder further comprises zinc stearate.

5. The composite friction powder for preparing brake pads according to claim 4, characterized in that: The mass ratio of the liquid cardanol phenolic resin to zinc stearate is 1:(0.05-0.11).

6. A composite friction material, characterized in that: The invention comprises the composite friction powder for preparing a brake pad according to any one of claims 1 to 5, wherein the composite friction powder has a content of 8-15 wt %.

7. The composite friction material according to claim 6, characterized in that: The composite friction material further includes the following components in the following percentages: 15-18wt% of modified phenolic resin, 2-4wt% of potassium feldspar powder, 5-8wt% of cryolite powder, 3-5wt% of talc powder, 3-5wt% of powdered nitrile, 10-14wt% of barium sulfate, 4-7wt% of ferrotitanium green, 1-3wt% of glass fiber, 4-5wt% of mineral fiber, and the balance is ceramic fiber.

8. The composite friction material according to claim 7, characterized in that: The powdered butyronitrile is molybdenum disulfide modified powdered butyronitrile.

9. A brake lining, characterized in that: The raw materials for preparing the composite friction material include the composite friction material according to any one of claims 6 to 8.

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