A friction material using modified earthy graphite as a friction performance modifier, a preparation method and application thereof

Abstract

The application discloses a kind of modified earth-like graphite as friction performance regulator's friction material, preparation method and application, belong to the technical field of friction material.The friction material includes the following components by mass fraction: phenolic resin 13-18 parts, fiber reinforced material 17-23 parts, modified earth-like graphite 5-15 parts, filler 40-60 parts;The modified earth-like graphite is prepared by the following method: (1) the earth-like graphite is crushed, grinded, and passed through 100-300 mesh screen to obtain earth-like graphite powder;(2) the earth-like graphite powder is placed in a vacuum environment and heated to 600-1000℃ for 4-6h;(3) the earth-like graphite powder treated in (2) is naturally cooled to room temperature to obtain the modified earth-like graphite.The friction material uses modified earth-like graphite as friction performance regulator, the crystallinity of the modified earth-like graphite increases, the wear resistance improves, so that the friction material has high wear resistance and stable friction coefficient, and is suitable for preparing brake products such as automobile brake pads.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of friction materials, in particular to a friction material taking modified soil-like graphite as a friction performance regulator, a preparation method and application. BACKGROUND

[0002] The friction material is a component material applied on a power machine and used for braking and transmission functions by means of friction. The friction material is usually a composite material formed by a high polymer binder, reinforced fiber material, friction performance regulator and fillers and the like in a mold through hot pressing and the like. The friction performance regulator can regulate the friction coefficient of the friction material and further regulate the friction performance of the friction material. Meanwhile, as an important component of the friction material, the friction performance regulator can also regulate the wear resistance of the whole friction material. The friction material is usually used to manufacture brake pads and other key safety components in the automobile industry, and its functional position is self-evident. In actual application, the friction coefficient and wear resistance of the friction material need to be considered.

[0003] The flake graphite sheet is thin and tough, and has excellent physical and chemical properties. The friction coefficient of the natural flake graphite is small, the lubricity is the best, the plasticity is the highest, and the wear resistance is relatively strong, and the flake graphite is one of the most common friction performance regulators of the friction material. However, in the field of manufacturing automobile brake pads, the content of the flake graphite in the friction material is difficult to adjust. If the content is too high, the friction coefficient of the friction material will sharply decrease, resulting in brake failure and causing safety accidents. If the content is too low, the wear resistance of the friction material will be insufficient, resulting in that the manufactured brake pad is quickly worn, the service period is short, the safety risk is high, and the replacement cost is high.

[0004] Therefore, it is difficult to manufacture a low-cost friction material with stable friction coefficient and high wear resistance. SUMMARY

[0005] Therefore, the application aims to provide a friction material taking modified soil-like graphite as a friction performance regulator, a preparation method and application. The soil-like graphite has a relatively stable friction coefficient. On this basis, the soil-like graphite is modified to further improve the wear resistance of the soil-like graphite. The friction material taking the modified soil-like graphite as a friction performance regulator has the characteristics of stable friction coefficient and high wear resistance, and is suitable for manufacturing brake products such as automobile brake pads.

[0006] To achieve or at least partially achieve the above-mentioned purposes, the application provides the following technical solutions.

[0007] In a first aspect, the application provides a friction material taking modified soil-like graphite as a friction performance regulator, which comprises the following components in parts by mass:

[0008] phenolic resin 13-18 parts, fiber reinforced material 17-23 parts, modified earthy graphite 5-15 parts, filler 40-60 parts;

[0009] The modified earthy graphite is prepared by the following method:

[0010] (1) crushing and grinding the earthy graphite, and passing through a 100-300 mesh sieve to obtain earthy graphite powder;

[0011] (2) placing the earthy graphite powder in a vacuum environment and heating to 600-1000°C for 4-6 hours;

[0012] (3) naturally cooling the earthy graphite powder treated in (2) to room temperature to obtain the modified earthy graphite.

[0013] In a second aspect, the application provides a preparation method of the aforementioned friction material, comprising the following steps:

[0014] (1) preparing the modified earthy graphite according to the aforementioned method;

[0015] (2) preparing phenolic resin, fiber reinforced material, modified earthy graphite, and filler according to mass parts, and mixing to form a friction material premix;

[0016] (3) hot-pressing the friction material premix obtained in (2) to obtain a friction material preform;

[0017] (4) heat-treating the friction material preform obtained in (3) to obtain a friction material with modified earthy graphite as a friction performance regulator.

[0018] In a third aspect, the application provides the use of the aforementioned friction material in the preparation of brake pads.

[0019] The friction material with modified earthy graphite as a friction performance regulator, the preparation method and the use provided by the application have at least the following beneficial effects compared with the prior art:

[0020] 1. The friction material provided by the application uses modified earthy graphite as a friction performance regulator. The crystallinity of the modified earthy graphite increases, and the wear resistance improves, so that the friction material has high wear resistance and stable friction coefficient.

[0021] 2. The preparation method of the friction material provided by the application has wide raw material sources, simple operation, low preparation cost, easy control of product performance, and is suitable for large-scale production.

[0022] 3. The friction material provided by the application is suitable for the preparation of brake products, such as automobile brake pads. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The AK Master experiment before and after the real object comparison diagram for friction material M3, wherein (a)-(d) are respectively the real object diagram of the front face before the experiment, the side face before the experiment, the front face after the experiment, and the side face after the experiment of friction material M3.

[0024] Figure 2 The AK Master experiment before and after the real object comparison diagram for friction material M6, wherein (a)-(d) are respectively the real object diagram of the front face before the experiment, the side face before the experiment, the front face after the experiment, and the side face after the experiment of friction material M6.

[0025] Figure 3 The AK Master experiment before and after the real object comparison diagram for friction material M7, wherein (a)-(d) are respectively the real object diagram of the front face before the experiment, the side face before the experiment, the front face after the experiment, and the side face after the experiment of friction material M7. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0027] It can be understood by those skilled in the art that, unless specifically stated otherwise, "the" and "that" and "the foregoing" used in the text of the present application can also include the plural form. It should be further understood that the phrase "comprising" used in the specification of the present application means that the features, steps, operations exist, but does not exclude the existence or addition of one or more other features, integers, steps.

[0028] It can be understood by those skilled in the art that, unless specific experimental steps or conditions are indicated in the examples, the operation or conditions can be carried out according to the conventional experimental steps described in the literature in the art; and the raw materials or instruments and equipment not indicated by the manufacturer are all conventional products that can be obtained by purchase.

[0029] It can be understood by those skilled in the art that, unless otherwise stated in the present application, when the examples give a numerical range, each numerical range and any number between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present application are used in the same manner as the present technical personnel's understanding of the prior art and the description of the present application, and any method, equipment and material of the prior art similar or equivalent to the method, equipment and material described in the examples of the present application can be used to realize the present application.

[0030] The existing friction material mostly uses flaky graphite as a friction performance regulator, but such friction material often cannot simultaneously have high wear resistance and stable friction coefficient, and there are problems such as safety risk, replacement cost and the like in using such friction material to prepare automobile braking products such as brake pads. Earthy graphite has high source and lower cost than flaky graphite, and has relatively stable friction coefficient but lower wear resistance than flaky graphite. The applicant has found through research that the wear resistance of modified earthy graphite obtained by grinding and heat treatment of earthy graphite is significantly improved, and on this basis, the modified earthy graphite is used as a friction performance regulator to prepare a brand-new friction material, which is verified to have good wear resistance and stable friction coefficient compared with the existing friction material, and is suitable for preparing automobile brake pads and other braking products.

[0031] Based on this, the embodiment of the present application provides a kind of friction material with modified earthy graphite as friction performance regulator, by mass parts, including the following components: phenolic resin 13-18 parts, fiber reinforced material 17-23 parts, modified earthy graphite 5-15 parts, filler 40-60 parts;The modified earthy graphite is prepared by the following method:

[0032] (1) the earthy graphite is crushed, ground, and passed through a 100-300 mesh screen to obtain earthy graphite powder;

[0033] (2) the earthy graphite powder is placed in a vacuum environment and heated to 600-1000°C for 4-6 hours;

[0034] (3) the earthy graphite powder treated in (2) is naturally cooled to room temperature to obtain the modified earthy graphite.

[0035] In the composition formula of the above friction material, the phenolic resin serves as a binder, which provides a rigid structure for the cured friction material, making the friction material easy to shape and allowing other components to be closely combined; the fiber reinforced material makes the friction material have strong tensile and bending strength; the modified earthy graphite serves as a friction performance regulator to adjust the friction coefficient of the friction material, increase the wear resistance, and improve the impact resistance; the filler is used to improve the mechanical properties of the friction material, enhance the structural strength of the friction material, and reduce the use of expensive materials and the production cost of the friction material without affecting the performance of the friction material.

[0036] In some embodiments, the fiber reinforced material is at least one of mineral wool fiber and glass fiber.

[0037] In some preferred embodiments, the fiber reinforced material is mineral wool fiber and glass fiber.

[0038] In some embodiments, the filler is at least one of barium sulfate, heavy calcium carbonate, and vermiculite powder.

[0039] In some preferred embodiments, the friction material using modified soil-like graphite as a friction performance regulator comprises, by mass fraction, the following components: phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, modified soil-like graphite 7-13 parts, and barium sulfate 52 parts.

[0040] In some more preferred embodiments, the friction material using modified soil-like graphite as a friction performance regulator comprises, by mass fraction, the following components: phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, modified soil-like graphite 9 parts, and barium sulfate 52 parts.

[0041] In some embodiments, the heating rate in the second step of preparing modified soil-like graphite is 10°C / min.

[0042] Based on this, the embodiments of the present application provide a preparation method of the aforementioned friction material, comprising the following steps: (1) preparing modified soil-like graphite according to the aforementioned method; (2) preparing phenolic resin, fiber reinforcement, modified soil-like graphite, and filler by mass fraction, and mixing to form a friction material premix; (3) hot-pressing the friction material premix obtained in (2) to obtain a friction material preform; and (4) heat treating the friction material preform obtained in (3) to obtain a friction material using modified soil-like graphite as a friction performance regulator.

[0043] In some embodiments, in the hot-pressing process in (3), the hot-pressing temperature is 120-160°C, the hot-pressing pressure is 8-25 MPa, and the hot-pressing time is 10-30 min.

[0044] In some embodiments, in the heat treatment process in (4), the heat treatment temperature is 100-160°C, and the heat treatment time is 4-8 h.

[0045] Based on this, the embodiments of the present application provide the use of the aforementioned friction material in the preparation of brake pads.

[0046] The technical solutions and technical effects of the present application are described in more detail below through more specific embodiments.

[0047] Embodiment 1

[0048] The present embodiment provides a preparation method of a friction material using modified soil-like graphite as a friction performance regulator, and the specific steps are as follows:

[0049] (1) obtaining 100-mesh modified soil-like graphite powder according to the aforementioned method;

[0050] (2) Take phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, modified earthy graphite 5 parts, and barium sulfate 52 parts by mass, mix and stir for 15 min, obtain the friction material premix, reserve;

[0051] (3) Take 220g of the friction material obtained in (2) and pour it into an 85mm x 85mm hot pressing mold, and perform hot pressing at a temperature of 130℃ and a pressure of 20Mpa, the hot pressing time is 20min, obtain the friction material preform;

[0052] (4) Put the friction material preform obtained in (3) into a muffle furnace for heat treatment, the heat treatment temperature is 150℃, the heat treatment time is 6h, and finally naturally cool to room temperature, to obtain the friction material M1 with modified earthy graphite as the friction performance regulator.

[0053] Example 2

[0054] The embodiment provides a preparation method of a friction material with modified earthy graphite as a friction performance regulator, and the specific steps are as follows:

[0055] (1) Obtain the 100 mesh modified earthy graphite powder according to the foregoing method;

[0056] (2) Take phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, modified earthy graphite 7 parts, and barium sulfate 52 parts by mass, mix and stir for 15 min, obtain the friction material premix, reserve;

[0057] (3) Take 220g of the friction material obtained in (2) and pour it into an 85mm x 85mm hot pressing mold, and perform hot pressing at a temperature of 130℃ and a pressure of 20Mpa, the hot pressing time is 20min, obtain the friction material preform;

[0058] (4) Put the friction material preform obtained in (3) into a muffle furnace for heat treatment, the heat treatment temperature is 150℃, the heat treatment time is 6h, and finally naturally cool to room temperature, to obtain the friction material M2 with modified earthy graphite as the friction performance regulator.

[0059] Example 3

[0060] The embodiment provides a preparation method of a friction material with modified earthy graphite as a friction performance regulator, and the specific steps are as follows:

[0061] (1) Obtain the 100 mesh modified earthy graphite powder according to the foregoing method;

[0062] (2) Take phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, modified earthy graphite 9 parts, and barium sulfate 52 parts by mass, mix and stir for 15 min, obtain the friction material premix, reserve;

[0063] (3) Take 220g of the friction material obtained in (2) and pour it into an 85mm x 85mm hot pressing mold, and perform hot pressing at a temperature of 130℃ and a pressure of 20Mpa, the hot pressing time is 20min, obtain the friction material preform;

[0064] (4) Put the friction material preform obtained in (3) into a muffle furnace for heat treatment, the heat treatment temperature is 150℃, the heat treatment time is 6h, and finally naturally cool to room temperature, to obtain the friction material M3 with modified earthy graphite as the friction performance regulator.

[0065] Example 4

[0066] The embodiment provides a preparation method of a friction material with modified earthy graphite as a friction performance regulator, and the specific steps are as follows:

[0067] (1) Obtain the modified earthy graphite powder of 100 mesh according to the foregoing method;

[0068] (2) Take phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, modified earthy graphite 13 parts, and barium sulfate 52 parts by mass, mix and stir for 15 min, obtain the friction material premix, reserve;

[0069] (3) Take 220g of the friction material obtained in (2) and pour it into an 85mm x 85mm hot pressing mold, and perform hot pressing at a temperature of 130℃ and a pressure of 20Mpa, the hot pressing time is 20min, obtain the friction material preform;

[0070] (4) Put the friction material preform obtained in (3) into a muffle furnace for heat treatment, the heat treatment temperature is 150℃, the heat treatment time is 6h, and finally naturally cool to room temperature, to obtain the friction material M4 with modified earthy graphite as the friction performance regulator.

[0071] Example 5

[0072] The embodiment provides a preparation method of a friction material with modified earthy graphite as a friction performance regulator, and the specific steps are as follows:

[0073] (1) Obtain the modified earthy graphite powder of 100 mesh according to the foregoing method;

[0074] (2) Take phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, modified earthy graphite 15 parts, and barium sulfate 52 parts by mass, mix and stir for 15 min, obtain the friction material premix, standby;

[0075] (3) Take 220g of the friction material obtained in (2) and pour it into an 85mmx85mm hot pressing mold, and perform hot pressing under the conditions of temperature 130℃ and pressure 20Mpa, hot pressing time 20min, obtain the friction material preform;

[0076] (4) Put the friction material preform obtained in (3) into a muffle furnace for heat treatment, heat treatment temperature is 150℃, heat treatment time is 6h, and finally naturally cool to room temperature, to obtain the friction material M5 with modified earthy graphite as the friction performance regulator.

[0077] Example 6

[0078] The embodiment provides a preparation method of a friction material with modified earthy graphite as a friction performance regulator, and the specific steps are as follows:

[0079] (1) Obtain 200 mesh modified earthy graphite powder according to the foregoing method;

[0080] (2) Take phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, modified earthy graphite 9 parts, and barium sulfate 52 parts by mass, mix and stir for 15 min, obtain the friction material premix, standby;

[0081] (3) Take 220g of the friction material obtained in (2) and pour it into an 85mmx85mm hot pressing mold, and perform hot pressing under the conditions of temperature 130℃ and pressure 20Mpa, hot pressing time 20min, obtain the friction material preform;

[0082] (4) Put the friction material preform obtained in (3) into a muffle furnace for heat treatment, heat treatment temperature is 150℃, heat treatment time is 6h, and finally naturally cool to room temperature, to obtain the friction material M6 with modified earthy graphite as the friction performance regulator.

[0083] Example 7

[0084] The embodiment provides a preparation method of a friction material with modified earthy graphite as a friction performance regulator, and the specific steps are as follows:

[0085] (1) Obtain 300 mesh modified earthy graphite powder according to the foregoing method;

[0086] (2) According to mass parts, phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, modified earthy graphite 9 parts, barium sulfate 52 parts are taken, mixed and stirred for 15 min to obtain a friction material premix, ready for use;

[0087] (3) 220 g of the friction material obtained in (2) is weighed and poured into a hot pressing mold of 85 mm x 85 mm, and hot pressing is performed under the conditions of temperature 130℃ and pressure 20Mpa, the hot pressing time is 20 min, and a friction material preform is obtained;

[0088] (4) The friction material preform obtained in (3) is placed in a muffle furnace for heat treatment, the heat treatment temperature is 150℃, the heat treatment time is 6h, and finally the natural cooling to room temperature is obtained, that is, the modified earthy graphite as a friction performance regulator is obtained. The friction material M7.

[0089] Comparative Example 1

[0090] The present comparative example provides a preparation method of a friction material, the specific steps are:

[0091] (1) The modified earthy graphite powder of 100 mesh is obtained according to the foregoing method;

[0092] (2) According to mass parts, phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, modified earthy graphite 4 parts, barium sulfate 52 parts are taken, mixed and stirred for 15 min to obtain a friction material premix, ready for use;

[0093] (3) 220 g of the friction material obtained in (2) is weighed and poured into a hot pressing mold of 85 mm x 85 mm, and hot pressing is performed under the conditions of temperature 130℃ and pressure 20Mpa, the hot pressing time is 20 min, and a friction material preform is obtained;

[0094] (4) The friction material preform obtained in (3) is placed in a muffle furnace for heat treatment, the heat treatment temperature is 150℃, the heat treatment time is 6h, and finally the natural cooling to room temperature is obtained, that is, the modified earthy graphite as a friction performance regulator is obtained. The friction material M7.

[0095] Comparative Example 2

[0096] The present comparative example provides a preparation method of a friction material, the specific steps are:

[0097] (1) The modified earthy graphite powder of 100 mesh is obtained according to the foregoing method;

[0098] (2) According to mass parts, phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, modified earthy graphite 16 parts, barium sulfate 52 parts are taken, mixed and stirred for 15 min to obtain a friction material premix, ready for use;

[0099] (3) Take 220g of the friction material obtained in (2) and pour it into a hot-pressing mold of 85mmx85mm, and hot-press it under the conditions of temperature 130℃ and pressure 20Mpa, with a hot-pressing time of 20min, to obtain a friction material preform;

[0100] (4) Put the friction material preform obtained in (3) into a muffle furnace for heat treatment, with a heat treatment temperature of 150℃ and a heat treatment time of 6h, and finally naturally cool to room temperature to obtain the friction material M9.

[0101] Comparative Example 3

[0102] The present comparative example provides a preparation method of a friction material, and the specific steps are as follows:

[0103] (1) Take phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, flake graphite 5 parts, and barium sulfate 52 parts by mass fraction, mix and stir for 15min to obtain a friction material premix, for standby use;

[0104] (2) Take 220g of the friction material obtained in (1) and pour it into a hot-pressing mold of 85mmx85mm, and hot-press it under the conditions of temperature 130℃ and pressure 20Mpa, with a hot-pressing time of 20min, to obtain a friction material preform;

[0105] (3) Put the friction material preform obtained in (2) into a muffle furnace for heat treatment, with a heat treatment temperature of 150℃ and a heat treatment time of 6h, and finally naturally cool to room temperature to obtain the friction material M10.

[0106] Comparative Example 4

[0107] The present comparative example provides a preparation method of a friction material, and the specific steps are as follows:

[0108] (1) Take phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, flake graphite 9 parts, and barium sulfate 52 parts by mass fraction, mix and stir for 15min to obtain a friction material premix, for standby use;

[0109] (2) Take 220g of the friction material obtained in (1) and pour it into a hot-pressing mold of 85mmx85mm, and hot-press it under the conditions of temperature 130℃ and pressure 20Mpa, with a hot-pressing time of 20min, to obtain a friction material preform;

[0110] (3) Put the friction material preform obtained in (2) into a muffle furnace for heat treatment, with a heat treatment temperature of 150℃ and a heat treatment time of 6h, and finally naturally cool to room temperature to obtain the friction material M11.

[0111] Comparative Example 5

[0112] The comparative example provides a preparation method of a friction material, and the specific steps are as follows:

[0113] (1) 16 parts of phenolic resin, 10 parts of mineral wool fiber, 10 parts of glass fiber, 15 parts of flake graphite, and 52 parts of barium sulfate were mixed and stirred for 15 min to obtain a friction material premix, which was used for standby;

[0114] (2) 220 g of the friction material obtained in (1) was weighed and poured into a hot-pressing mold with a size of 85 mm x 85 mm, and hot-pressing was performed at a temperature of 130°C and a pressure of 20 Mpa for 20 min to obtain a friction material preform;

[0115] (3) The friction material preform obtained in (1) was placed in a muffle furnace for heat treatment, the heat treatment temperature was 150°C, the heat treatment time was 6 h, and finally the temperature was naturally cooled to room temperature to obtain the friction material M12.

[0116] Comparative Example 6

[0117] The comparative example provides a preparation method of a friction material, and the specific steps are as follows:

[0118] (1) 16 parts of phenolic resin, 10 parts of mineral wool fiber, 10 parts of glass fiber, 15 parts of flake graphite, and 52 parts of barium sulfate were mixed and stirred for 15 min to obtain a friction material premix, which was used for standby;

[0119] (2) 220 g of the friction material obtained in (1) was weighed and poured into a hot-pressing mold with a size of 85 mm x 85 mm, and hot-pressing was performed at a temperature of 130°C and a pressure of 20 Mpa for 20 min to obtain a friction material preform;

[0120] (3) The friction material preform obtained in (1) was placed in a muffle furnace for heat treatment, the heat treatment temperature was 150°C, the heat treatment time was 6 h, and finally the temperature was naturally cooled to room temperature to obtain the friction material M12.

[0121] The friction performance of the friction materials M1-M13 prepared above was tested according to the AK Master standard, and the test items included wear thickness and friction coefficient to evaluate the wear resistance and stability of the friction coefficient of each friction material. The test results are shown in Table 1 as follows:

[0122] Table 1

[0123] Serial number Example / Comparative example Friction material number Main difference parameter Average wear thickness (mm) Average friction coefficient 1 Example 1 M1 100 mesh modified earthy graphite 5 parts 1.8653 0.346 2 Example 2 M2 100 mesh modified earthy graphite 7 parts 1.6749 0.338 3 Example 3 M3 100 mesh modified earthy graphite 9 parts 1.5116 0.324 4 Example 4 M4 100 mesh modified earthy graphite 13 parts 1.8587 0.325 5 Example 5 M5 100 mesh modified earthy graphite 15 parts 2.0093 0.310 6 Example 6 M6 200 mesh modified earthy graphite 9 parts 2.1491 0.351 7 Example 7 M7 300 mesh modified earthy graphite 9 parts 2.1958 0.401 8 Comparative example 1 M8 100 mesh modified earthy graphite 4 parts 2.2267 0.355 9 Comparative example 2 M9 100 mesh modified earthy graphite 16 parts 2.2091 0.290 10 Comparative example 3 M10 Flaky graphite 5 parts 2.2303 0.281 11 Comparative example 4 M11 Flaky graphite 9 parts 1.5435 0.194 12 Comparative example 5 M12 Flaky graphite 15 parts 1.4326 0.136 13 Comparative example 6 M13 Unmodified earthy graphite 9 parts 2.9584 0.344

[0124] From the test results of the data in Table 1, it can be seen that the average wear thickness of the friction materials M1-M7 prepared in Examples 1-7 is between 1.5116-2.1958 mm, the wear resistance is good, the average friction coefficient is between 0.310-0.401, and the fluctuation range is small. This shows that when the modified soil-like graphite in the friction material is 5-15 parts and the mesh size is between 100-300 meshes, the prepared friction material meets the requirements of high wear resistance and stable friction coefficient.

[0125] From the analysis of the average wear thickness data of the friction materials M3 and M13 prepared in Example 3 and Comparative Example 6 in Table 1, it can be seen that the friction performance modifier in M13 uses unmodified soil-like graphite, although the friction coefficient meets the requirements, but the wear resistance is poor.

[0126] From the analysis of the average wear thickness data of M1-M5 prepared in Examples 1-5 in Table 1, it can be seen that when the mass fraction of modified soil-like graphite is further reduced (7-13 parts by mass), the average wear thickness is further reduced, indicating that the wear resistance is further improved, and when the mass fraction of modified soil-like graphite is 9 parts, the average wear thickness reaches the lowest 1.5116 mm, indicating that the wear resistance is the best.

[0127] From the analysis of the wear resistance of the friction materials M3, M6, and M7 prepared in Examples 3, 6, and 7 in Table 1, it is found that M3 is better than M6 and M7, indicating that the powder particle size of modified soil-like graphite as a friction material modifier also affects the wear resistance of the final friction material. When the mesh size of the modified soil-like graphite powder is 100, the wear resistance of the prepared friction material is the best. Figures 1 to 3 The real object comparison chart before and after AK Master experiment of friction materials M3, M6, and M7, respectively.

[0128] From the analysis of the average wear thickness and friction coefficient data of the friction materials M10, M11, and M12 prepared in Comparative Examples 3-5 in Table 1, it can be seen that when the content of flake graphite in the friction material is low (5 parts by mass), the wear resistance is poor; when the mass fraction of flake graphite is increased, although the wear resistance is improved, the average friction coefficient shows a sharp downward trend, and when the mass fraction of flake graphite is 9 parts, the average friction coefficient is less than 0.2, the braking safety is low, and if this friction material is used to manufacture automobile brake pads, it is difficult to balance the wear resistance and suitable friction coefficient.

[0129] In summary, the friction material prepared in the examples of the present application has high wear resistance and stable friction coefficient, and can replace flake graphite to manufacture friction materials and other products, reducing production cost.

[0130] The application is described in detail above, and the principles and implementation manners of the application are described by applying specific examples. The above description of the examples is only used to help understand the application and the core idea. It should be pointed out that, for ordinary skilled persons in the technical field, some improvements and modifications can be made to the application without departing from the principles of the application, and these improvements and modifications also fall within the protection scope of the claims of the application.

Claims

1. A friction material using a modified earthy graphite as a friction property adjusting agent, characterized by, By mass fraction, the friction material comprises the following components: phenolic resin 13-18 parts, fiber reinforced material 17-23 parts, modified earthy graphite 5-15 parts, filler 40-60 parts; the modified earthy graphite is prepared by the following method: (1) crushing and grinding the earthy graphite, passing through a 100-300 mesh sieve to obtain earthy graphite powder; (2) placing the earthy graphite powder in a vacuum environment and heating to 600-1000 ℃ for 4-6 h; (3) naturally cooling the treated earthy graphite powder to room temperature to obtain the modified earthy graphite.

2. The friction material of claim 1, wherein The fiber reinforced material is at least one of mineral wool fiber and glass fiber.

3. The friction material of claim 1, wherein The fiber reinforced material is mineral wool fiber and glass fiber.

4. The friction material of claim 1 wherein, The filler is at least one of barium sulfate, heavy calcium carbonate and vermiculite powder.

5. The friction material of claim 1 wherein, The fiber reinforced material is mineral wool fiber and glass fiber, and the filler is barium sulfate; by mass fraction, the friction material comprises the following components: phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, modified earthy graphite 7-13 parts, and barium sulfate 52 parts.

6. The friction material of claim 5 wherein, The friction material, by mass fraction, comprises the following components: phenolic resin 16 parts, mineral wool fiber 10 parts, glass fiber 10 parts, modified earthy graphite 9 parts, and barium sulfate 52 parts.

7. The method of making the friction material of claim 1, wherein, The method comprises the following steps: (1) preparing modified earthy graphite; (2) preparing phenolic resin, fiber reinforced material, modified earthy graphite and filler by mass fraction, and mixing to form a friction material premix; (3) hot-pressing the friction material premix obtained in (2) to obtain a friction material preform; (4) heat treating the friction material preform obtained in (3) to obtain a friction material with modified earthy graphite as a friction performance regulator.

8. The preparation method according to claim 7, characterized in that, In the hot-pressing process in (3), the hot-pressing temperature is 120-160 ℃, the hot-pressing pressure is 8-25 Mpa, and the hot-pressing time is 10-30 min.

9. The preparation method according to claim 7, characterized in that, In the heat treatment process in (4), the heat treatment temperature is 100-160 ℃, and the heat treatment time is 4-8 h.

10. Use of the friction material according to any one of claims 1-6 in the preparation of brake pads.

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