Friction material, brake pad and preparation method of friction material

Abstract

The invention provides a friction material, a brake pad and a preparation method of the brake pad, and relates to the technical field of brake pads. The friction material comprises the following components in percentage by weight: 8-15% of a binding agent, 5-15% of a friction increasing agent, 8-15% of a friction reducing agent, 15-25% of reinforced fibers, 20-40% of a friction performance regulator and 3-12% of a corrosion inhibitor. According to the friction material, the rust bonding problem of the brake pad can be effectively relieved, the problem that the brake pad locally falls off or the material is broken due to rust bonding is reduced, the brake pad can keep good friction performance and abrasion resistance, and the service life is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of brake pads, and particularly relates to a friction material, a brake pad and a preparation method thereof. Background Art

[0002] A pumping unit is a key device for oil extraction, usually installed outdoors, and its working conditions are usually relatively complex and harsh. If the brake pads of the pumping unit are locked with the counterpart, affected by environmental temperature and humidity, especially in rainy and snowy weather, various chemical corrosion reactions are likely to occur on the surface of the brake pads and the counterpart surface, such as oxidation corrosion and electrochemical corrosion. In the case of various corrosion reactions, rust adhesion phenomenon can occur in a short period of time, resulting in the brake pads being adhered to the surface of the counterpart, which is likely to cause the brake pads to tear or fall off, posing a great potential safety hazard. Summary of the Invention

[0003] In view of the above problems existing in the prior art, the present invention provides a friction material, a brake pad and a preparation method thereof to improve the rust adhesion problem of the brake pads and reduce the adhesion and locking phenomenon between the brake pads and the counterpart.

[0004] To achieve the above object and other related objects, in a first aspect of the present invention, there is provided a friction material, characterized in that, based on the weight percentage of the friction material, the friction material comprises the following components and the content of each component is: binder 8 - 15%, friction enhancer 5 - 15%, friction reducer 8 - 15%, reinforcing fiber 15 - 25%, friction performance regulator 20 - 40%, corrosion inhibitor 3 - 12%.

[0005] In an embodiment of the present invention, based on the weight percentage of the binder, the binder comprises the following components and the content of each component is: linear pure phenolic resin 40 - 70%, silicon-modified phenolic resin 30 - 60%, acrylic acid-modified phenolic resin 0 - 30%.

[0006] In an embodiment of the present invention, based on the weight percentage of the friction enhancer, the friction enhancer comprises the following components and the content of each component is: magnesium oxide 30 - 70%, zirconium silicate 30 - 70%.

[0007] In an embodiment of the present invention, based on the weight percentage of the friction reducer, the friction reducer comprises the following components and the content of each component is: natural graphite 50 - 70%, artificial graphite 30 - 50%.

[0008] In an embodiment of the present invention, based on the weight percentage of the reinforcing fiber, the reinforcing fiber comprises the following components and the content of each component is: aramid fiber 20 - 45%, mineral fiber 55 - 80%.

[0009] In one embodiment of the present invention, based on the weight percentage of the friction performance regulator, the friction performance regulator comprises the following components and the content of each component is as follows: potassium titanate 0-50%, antimony sulfide 10-30%, calcium carbonate 30-60%, calcium hydroxide 2-15%, and rubber powder 4-15%.

[0010] In one embodiment of the present invention, based on the weight percentage of the corrosion inhibitor, the corrosion inhibitor comprises the following components and the content of each component is as follows: sodium nitrite 50-70%, benzotriazole 20-50%, and polyethylene 0-30%.

[0011] The second aspect of the present invention provides a method for preparing a brake pad, comprising the following steps:

[0012] Mixing and blending of raw materials of the friction material: weighing the above-mentioned friction material according to the proportion and mixing it evenly;

[0013] Hot pressing and forming: putting the steel back and the friction material into a hot pressing mold for pressing and forming to obtain a brake pad blank;

[0014] Heat treatment: baking the brake pad blank at 200-250 °C for 2-4 h, and taking it out after cooling;

[0015] Post-treatment: grinding the heat-treated brake pad blank to the required size to obtain a brake pad.

[0016] In one embodiment of the present invention, the pressure of the hot pressing and forming is 6-10 MPa, the temperature of the hot pressing and forming is 140-160 °C, and the pressure holding time of the hot pressing and forming is 300-400 s.

[0017] The third aspect of the present invention provides a brake pad, which is made by the above preparation method.

[0018] The friction material of the present invention can alleviate the problem of rust adhesion of the brake pad through the cooperation of the corrosion inhibitor and the binder. Further, the binder is selected as a modified binder material to enhance the hydrophobicity of the material, achieve the problem of preventing rust adhesion, and alleviate the adhesion and locking phenomenon between the brake pad and the counterpart. The brake pad including this friction material has good friction performance and wear resistance, can extend the service life, and is applicable to pumping units. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other embodiments can also be obtained based on these drawings.

[0020] Figure 1 This is the preparation flow chart of the brake pads of the present invention in an embodiment. Specific embodiments

[0021] The following specific examples illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. It should also be understood that the terms used in the embodiments of the present invention are for the purpose of describing specific implementation manners and are not intended to limit the protection scope of the present invention. The test methods without specific conditions noted in the following embodiments are usually in accordance with conventional conditions or in accordance with the conditions recommended by each manufacturer.

[0022] When the embodiments give a numerical range, it should be understood that unless otherwise specified in the present invention, any value between the two endpoints of each numerical range and either endpoint can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention are the same as those understood by those skilled in the art of the present technology field and the records of the present invention. Any methods, devices, and materials similar or equivalent to the existing technologies in the methods, devices, and materials in the embodiments of the present invention can also be used to implement the present invention.

[0023] It should be noted that the terms such as "upper", "lower", "left", "right", "middle", and "one" cited in this specification are only for the convenience of clear narration and are not intended to limit the scope of implementation of the present invention. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope of implementation of the present invention.

[0024] The present invention provides a friction material. Calculated by weight percentage of the friction material, the friction material includes the following components and the content of each component is: binder 8-15%, friction modifier 5-15%, friction reducer 8-15%, reinforcing fiber 15-25%, friction performance regulator 20-40%, corrosion inhibitor 3-12%.

[0025] In an embodiment, calculated by weight percentage of the binder, the binder includes the following components and the content of each component is: linear pure phenolic resin 40-70%, silicon-modified phenolic resin 30-60%, acrylic acid-modified phenolic resin 0-30%.

[0026] In an embodiment, calculated by weight percentage of the friction modifier, the friction modifier includes the following components and the content of each component is: magnesium oxide 30-70%, zirconium silicate 30-70%.

[0027] In one embodiment, based on the weight percentage of the friction reducing agent, the friction reducing agent comprises the following components and the content of each component is as follows: natural graphite 50 - 70%, artificial graphite 30 - 50%.

[0028] In one embodiment, based on the weight percentage of the reinforcing fiber, the reinforcing fiber comprises the following components and the content of each component is as follows: aramid fiber 20 - 45%, mineral fiber 55 - 80%.

[0029] In one embodiment, based on the weight percentage of the friction property regulator, the friction property regulator comprises the following components and the content of each component is as follows: potassium titanate 0 - 50%, antimony sulfide 10 - 30%, calcium carbonate 30 - 60%, calcium hydroxide 2 - 15%, rubber powder 4 - 15%.

[0030] In one embodiment, based on the weight percentage of the corrosion inhibitor, the corrosion inhibitor comprises the following components and the content of each component is as follows: sodium nitrite 50 - 70%, benzotriazole 20 - 50%, polyethylene 0 - 30%.

[0031] The friction material of the present application can effectively improve the rust adhesion problem of the brake pads, reduce the problems of local shedding or material fragmentation of the brake pads caused by rust adhesion, is applicable to the brake pads for pumping units, enables the brake pads to maintain good friction performance and wear resistance, extends the service life, and can maintain good friction performance and wear resistance of the brake pads for pumping units and extend the service life.

[0032] Please refer to Figure 1 , the present application provides a preparation method for brake pads, comprising the following steps:

[0033] S1. Raw material mixing of the friction material: Weigh the friction material according to the proportion and mix it evenly;

[0034] S2. Hot pressing and forming: Put the steel back and the friction material into a hot pressing die to press and form, obtaining a brake pad blank;

[0035] S3. Heat treatment: Bake the brake pad blank at 200 - 250 °C for 2 - 4 h, and take it out after cooling;

[0036] S4. Post - treatment: Grind the heat - treated brake pad blank to the required size to obtain the brake pads.

[0037] In step S1, based on the weight percentage of the friction material, the friction material includes the following components and their contents are as follows: binder 8-15%, friction increasing agent 5-15%, friction reducing agent 8-15%, reinforcing fiber 15-25%, friction performance regulator 20-40%, corrosion inhibitor 3-12%. To ensure the uniform mixing of the friction material, each component of the friction material is weighed and placed in a high-speed mixer for mixing. Exemplarily, the rotating speed of the flying knife of the mixer is 3000 rmp, the rotating speed of the main shaft of the mixer is 300 rmp, and the stirring time is 5-10 min, such as any value in 5-10 min like 5 min, 8 min or 10 min. There is no limitation on the type of the mixer here, and a commonly used high-speed mixer in the field can be selected, such as a horizontal high-speed mixer.

[0038] In step S2, the pressure for hot pressing and forming is 6-10 MPa, such as any value in 6-10 MPa like 6 MPa, 8 MPa or 10 MPa; the temperature for hot pressing and forming is 140-160 °C, such as any value in 140-160 °C like 140 °C, 150 °C or 160 °C; the pressure holding time for hot pressing and forming is 300-400 s, such as any value in 300-400 s like 300 s, 350 s or 400 s. In some embodiments, pre-pressing is also included before hot pressing and forming the friction material and the steel back. The pre-pressing includes the following steps: after placing the friction material and the steel back in a hot pressing mold, pressing for 15-25 s under the conditions of 6-10 MPa and 140-160 °C and then exhausting the air, repeating the operation 3-4 times, and holding the pressure after the pre-pressing ends. Pre-pressing can remove air, avoid forming bubbles and voids inside the brake pad, improve the product density, not only can make the material evenly distributed in the mold, improve the forming quality and dimensional accuracy, but also can promote the combination between materials, enhance the bonding strength and improve the durability of the brake pad.

[0039] In step S3, there is no limitation on the pretreatment tool for the brake pad blank, and commonly used baking tools in the field can be used, such as an oven. After the baking ends, the temperature is naturally cooled to below 80 °C and then it is taken out to prevent the brake pad from deforming or cracking due to the thermal stress caused by the temperature difference, ensure the stability of the material performance, and at the same time avoid the high-temperature brake pad from causing harm to the operators and equipment, and facilitate subsequent processing and treatment.

[0040] This application also provides a brake pad, which is prepared by the above preparation method. The friction material of this brake pad effectively improves its rust adhesion problem, enables the brake pad to have good friction performance and wear resistance, extends the service life, and is applicable to pumping units.

[0041] The technical solution of the present invention will be described in detail through several specific embodiments. Unless otherwise specified, the raw materials and reagents used in the following embodiments are all commercially available products, or can be prepared by conventional methods in the art, and the instruments used in the embodiments can be purchased commercially.

[0042] Example 1

[0043] In this embodiment, the preparation method of the brake pad includes the following steps: (1) Weigh and mix the friction material according to the ratio of 10% binder, 14% friction modifier, 8% friction reducer, 17% reinforcing fiber, 40% friction performance regulator, and 11% corrosion inhibitor. (2) Place the steel back and the friction material into a hot pressing mold. The pressure of the hot pressing mold is 8 MPa, and the upper mold temperature, middle mold temperature, and lower mold temperature of the hot pressing mold are 150 °C, 145 °C, and 150 °C respectively. Under these conditions, after pressing for 20 s, exhaust for 10 s for pre-pressing, repeat 3 times, and then hold the pressure for 320 s to obtain a brake pad blank. (3) Place the obtained brake pad blank in an oven and bake at 200 °C for 3 h, and take it out after the temperature drops to 70 °C. (4) Grind the heat-treated brake pad blank to the required size to obtain the brake pad.

[0044] In this embodiment, based on the weight percentage of the binder, the binder includes 70% linear pure phenolic resin and 30% silicon-modified phenolic resin; based on the weight percentage of the friction modifier, the friction modifier includes 30% magnesium oxide and 70% zirconium silicate; based on the weight percentage of the friction reducer, the friction reducer includes 50% natural graphite and 50% artificial graphite; based on the weight percentage of the reinforcing fiber, the reinforcing fiber includes 20% aramid fiber and 80% mineral fiber; based on the weight percentage of the friction performance regulator, the friction performance regulator includes 35% potassium titanate, 15% antimony sulfide, 30% calcium titanate, 5% calcium hydroxide, and 15% rubber powder; based on the total weight of the corrosion inhibitor, the corrosion inhibitor includes 50% sodium nitrite and 50% benzotriazole.

[0045] Example 2

[0046] In this embodiment, the preparation method of the brake pad comprises the following steps: (1) Weigh and mix the friction material according to the ratio of 15% binder, 13% friction modifier, 12% anti-friction agent, 15% reinforcing fiber, 33% friction performance regulator, and 12% corrosion inhibitor. (2) Place the steel back and the friction material into a hot pressing mold. The pressure of the hot pressing mold is 10 MPa, and the upper mold temperature, middle mold temperature, and lower mold temperature of the hot pressing mold are 150 °C, 140 °C, and 150 °C respectively. Under these conditions, pre-press for 15 s and then exhaust for 10 s. Repeat this 3 times and then hold the pressure for 300 s to obtain the brake pad blank. (3) Place the obtained brake pad blank in an oven and bake it at 250 °C for 3 h, and take it out after the temperature drops to 70 °C. (4) Grind the heat-treated brake pad blank to the required size to obtain the brake pad.

[0047] In this embodiment, based on the weight percentage of the binder, the binder comprises 40% linear pure phenolic resin, 30% silicon-modified phenolic resin, and 30% acrylic acid-modified phenolic resin; based on the weight percentage of the friction modifier, the friction modifier comprises 40% magnesium oxide and 60% zirconium silicate; based on the weight percentage of the anti-friction agent, the anti-friction agent comprises 70% natural graphite and 30% artificial graphite; based on the weight percentage of the reinforcing fiber, the reinforcing fiber comprises 30% aramid fiber and 70% mineral fiber; based on the weight percentage of the friction performance regulator, the friction performance regulator comprises 25% antimony sulfide, 50% calcium titanate, 15% calcium hydroxide, and 10% rubber powder; based on the total weight of the corrosion inhibitor, the corrosion inhibitor comprises 60% sodium nitrite, 30% benzotriazole, and 10% polyethylene.

[0048] Example 3

[0049] In this embodiment, the preparation method of the brake pad comprises the following steps: (1) Weigh and mix the friction material according to the ratio of 8% binder, 15% friction modifier, 15% anti-friction agent, 23% reinforcing fiber, 32% friction performance regulator, and 7% corrosion inhibitor. (2) Place the steel back and the friction material into a hot pressing mold. The pressure of the hot pressing mold is 6 MPa, and the upper mold temperature, middle mold temperature, and lower mold temperature of the hot pressing mold are 160 °C, 150 °C, and 160 °C respectively. Under these conditions, pre-press for 25 s and then exhaust for 10 s. Repeat this 3 times and then hold the pressure for 400 s to obtain the brake pad blank. (3) Place the obtained brake pad blank in an oven and bake it at 250 °C for 2 h, and take it out after the temperature drops to 70 °C. (4) Grind the heat-treated brake pad blank to the required size to obtain the brake pad.

[0050] In this embodiment, based on the weight percentage of the binder, the binder includes 50% linear pure phenolic resin, 40% silicon-modified phenolic resin, and 10% acrylic acid-modified phenolic resin; based on the weight percentage of the friction-increasing agent, the friction-increasing agent includes 70% magnesium oxide and 30% zirconium silicate; based on the weight percentage of the friction-reducing agent, the friction-reducing agent includes 55% natural graphite and 45% artificial graphite; based on the weight percentage of the reinforcing fiber, the reinforcing fiber includes 45% aramid fiber and 55% mineral fiber; based on the weight percentage of the friction property regulator, the friction property regulator includes 50% potassium titanate, 10% antimony sulfide, 34% calcium titanate, 2% calcium hydroxide, and 4% rubber powder; based on the total weight of the corrosion inhibitor, the corrosion inhibitor includes 70% sodium nitrite, 20% benzotriazole, and 10% polyethylene.

[0051] Example 4

[0052] In this embodiment, the preparation method of the brake pad includes the following steps: (1) Weigh and mix the friction material according to the ratio of 12% binder, 8% friction-increasing agent, 12% friction-reducing agent, 25% reinforcing fiber, 40% friction property regulator, and 3% corrosion inhibitor. (2) Place the steel back and the friction material into a hot pressing mold. The pressure of the hot pressing mold is 10 MPa, and the upper mold temperature, middle mold temperature, and lower mold temperature of the hot pressing mold are 145 °C, 140 °C, and 145 °C respectively. Under these conditions, after pressing for 25 s, exhaust for 10 s for pre-pressing, repeat 3 times, and then hold the pressure for 350 s to obtain a brake pad blank. (3) Place the obtained brake pad blank in an oven and bake at 230 °C for 3.5 h, and take it out after the temperature drops to 80 °C. (4) Grind the heat-treated brake pad blank to the required size to obtain the brake pad.

[0053] In this embodiment, based on the weight percentage of the binder, the binder includes 40% linear pure phenolic resin and 60% silicon-modified phenolic resin; based on the weight percentage of the friction-increasing agent, the friction-increasing agent includes 35% magnesium oxide and 65% zirconium silicate; based on the weight percentage of the friction-reducing agent, the friction-reducing agent includes 60% natural graphite and 40% artificial graphite; based on the weight percentage of the reinforcing fiber, the reinforcing fiber includes 30% aramid fiber and 70% mineral fiber; based on the weight percentage of the friction property regulator, the friction property regulator includes 4% potassium titanate, 30% antimony sulfide, 60% calcium titanate, 2% calcium hydroxide, and 4% rubber powder; based on the total weight of the corrosion inhibitor, the corrosion inhibitor includes 50% sodium nitrite, 20% benzotriazole, and 30% polyethylene.

[0054] Example 5

[0055] In this embodiment, the preparation method of the brake pad includes the following steps: (1) Weigh and mix the friction material according to the ratio of 15% binder, 15% friction-increasing agent, 15% friction-reducing agent, 23% reinforcing fiber, 20% friction performance regulator, and 12% corrosion inhibitor. (2) Place the steel back and the friction material into a hot pressing mold. The pressure of the hot pressing mold is 10 MPa, and the upper mold temperature, middle mold temperature, and lower mold temperature of the hot pressing mold are 150 °C, 145 °C, and 150 °C respectively. Under these conditions, pre-press for 20 s and then exhaust for 10 s, repeat 3 times and then hold the pressure for 330 s to obtain the brake pad blank. (3) Place the obtained brake pad blank in an oven and bake at 200 °C for 4 h, and take it out after the temperature drops to 80 °C. (4) Grind the heat-treated brake pad blank to the required size to obtain the brake pad.

[0056] In this embodiment, the binder includes 40% linear pure phenolic resin, 35% silicon-modified phenolic resin, and 25% acrylic acid-modified phenolic resin; calculated by the weight percentage of the friction-increasing agent, the friction-increasing agent includes 50% magnesium oxide and 50% zirconium silicate; calculated by the weight percentage of the friction-reducing agent, the friction-reducing agent includes 40% natural graphite and 60% artificial graphite; calculated by the weight percentage of the reinforcing fiber, the reinforcing fiber includes 30% aramid fiber and 70% mineral fiber; calculated by the weight percentage of the friction performance regulator, the friction performance regulator includes 20% potassium titanate, 20% antimony sulfide, 30% calcium titanate, 15% calcium hydroxide, and 15% rubber powder; calculated by the total weight of the corrosion inhibitor, the corrosion inhibitor includes 60% sodium nitrite, 30% benzotriazole, and 10% polyethylene.

[0057] Example 6

[0058] In this embodiment, the preparation method of the brake pad includes the following steps: (1) Weigh and mix the friction material according to the ratio of 14% binder, 5% friction-increasing agent, 11% friction-reducing agent, 24% reinforcing fiber, 40% friction performance regulator, and 6% corrosion inhibitor. (2) Place the steel back and the friction material into a hot pressing mold. The pressure of the hot pressing mold is 7 MPa, and the upper mold temperature, middle mold temperature, and lower mold temperature of the hot pressing mold are 150 °C, 145 °C, and 150 °C respectively. Under these conditions, pre-press for 25 s and then exhaust for 10 s, repeat 3 times and then hold the pressure for 380 s to obtain the brake pad blank. (3) Place the obtained brake pad blank in an oven and bake at 250 °C for 2 h, and take it out after the temperature drops to 70 °C. (4) Grind the heat-treated brake pad blank to the required size to obtain the brake pad.

[0059] In this embodiment, based on the weight percentage of the binder, the binder includes 50% linear pure phenolic resin, 30% silicone-modified phenolic resin, and 20% acrylic acid-modified phenolic resin; based on the weight percentage of the friction-increasing agent, the friction-increasing agent includes 65% magnesium oxide and 35% zirconium silicate; based on the weight percentage of the friction-reducing agent, the friction-reducing agent includes 55% natural graphite and 45% artificial graphite; based on the weight percentage of the reinforcing fiber, the reinforcing fiber includes 40% aramid fiber and 60% mineral fiber; based on the weight percentage of the friction property regulator, the friction property regulator includes 10% potassium titanate, 20% antimony sulfide, 45% calcium titanate, 15% calcium hydroxide, and 10% rubber powder; based on the total weight of the corrosion inhibitor, the corrosion inhibitor includes 60% sodium nitrite, 30% benzotriazole, and 10% polyethylene.

[0060] The brake pads prepared in Examples 1 to 6 were subjected to performance tests. The pH value of the brake pads was tested according to the JASOC458-1986 test standard, the rust adhesion experiment of the brake pads was carried out according to the TL110 test standard, and the friction and wear experiment of the brake pads was carried out according to GB5763-2008. The performance evaluation criteria of the brake pads are shown in Table 1, and the performance test results of the brake pads prepared in Examples 1 to 6 are shown in Table 2:

[0061] Table 1 Performance evaluation criteria of brake pads

[0062] Specimen / Project Testing Standard Evaluation Standard pH Value JASOC458-1986 ≥9 Rust Adhesion TL110 <150N Specified Friction Coefficient GB5763-2008 Specified Friction Coefficient 0.38

[0063] Table 2 Performance test of brake pads prepared in Examples 1 to 6

[0064]

[0065]

[0066] It can be seen from Table 2 that the friction materials of the brake pads prepared in Examples 1 to 6 are alkaline, not easy to cause corrosion to the counterpart, can effectively relieve the seizure of the brake pads and the counterpart, and the friction coefficient of the brake pads is stable, which is suitable for pumping units.

[0067] The friction material of the present invention can relieve the rust adhesion problem of the brake pads through the cooperation of the corrosion inhibitor and the binder. Further, the binder is selected as a modified binder material to enhance the hydrophobicity of the material, achieve the problem of preventing rust adhesion, and relieve the adhesion seizure phenomenon between the brake pads and the counterpart. The brake pads including this friction material have good friction performance and wear resistance, can extend the service life, and are suitable for pumping units. Therefore, the present invention effectively overcomes some practical problems in the prior art and thus has high utilization value and practical significance.

[0068] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A friction material, characterized in that: The friction material comprises the following components in percentage by weight: 8-15% binder, 5-15% friction enhancer, 8-15% friction reducer, 15-25% reinforcing fiber, 20-40% friction performance regulator, and 3-12% corrosion inhibitor.

2. The friction material according to claim 1, characterized in that: The binder comprises the following components in percentage by weight: 40-70% of straight-chain pure phenolic resin, 30-60% of silicon-modified phenolic resin, and 0-30% of acrylic acid-modified phenolic resin.

3. The friction material according to claim 1, characterized in that: Calculated by weight percentage of the friction enhancer, the friction enhancer comprises the following components, and the contents of each component are: 30-70% of magnesium oxide and 30-70% of zirconium silicate.

4. The friction material according to claim 1, characterized in that: Calculated by weight percentage, the friction reducer comprises the following components and the content of each component is: 50-70% natural graphite and 30-50% artificial graphite.

5. The friction material according to claim 1, characterized in that: Calculated by weight percentage of the reinforcing fiber, the reinforcing fiber includes the following components and the content of each component is: 20-45% of aramid fiber and 55-80% of mineral fiber.

6. The friction material according to claim 1, characterized in that: The friction performance modifier comprises the following components in percentage by weight: 0-50% potassium titanate, 10-30% antimony sulfide, 30-60% calcium carbonate, 2-15% calcium hydroxide, and 4-15% rubber powder.

7. The friction material according to claim 1, characterized in that: Calculated by weight percentage, the corrosion inhibitor comprises the following components and the content of each component is: 50-70% sodium nitrite, 20-50% benzotriazole, and 0-30% polyethylene.

8. A method for preparing a brake pad, characterized in that: The steps include: Mixing of raw materials of friction material: weigh the friction material according to any one of claims 1 to 7 in proportion and mix them evenly; Hot pressing forming: placing the steel back and the friction material into a hot pressing mold for pressing and forming to obtain a brake pad blank; Heat treatment: baking the brake pad blank at 200-250° C. for 2-4 hours, and taking it out after cooling; Post-processing: Grind the heat-treated brake pad blank to the required size to obtain the brake pad.

9. The preparation method according to claim 8, characterized in that: The pressure of the hot pressing molding is 6-10 MPa, the temperature of the hot pressing molding is 140-160° C., and the holding time of the hot pressing molding is 300-400 s.

10. A brake pad, characterized in that: The brake pad is manufactured by the preparation method of the brake pad according to claim 8 or 9.

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