Friction material with modified amorphous graphite as friction performance modifier, preparation method and application

Abstract

The invention discloses a friction material with modified amorphous graphite as a friction performance modifier, a preparation method and application, and belongs to the technical field of friction materials. The friction material comprises the following components in parts by mass: 13-18 parts of phenolic resin, 17-23 parts of a fiber reinforced material, 5-15 parts of modified amorphous graphite and 40-60 parts of filler, the modified amorphous graphite is prepared by the following method: (1) crushing and grinding amorphous graphite, and sieving with a 100-300-mesh sieve to obtain amorphous graphite powder; (2) placing the amorphous graphite powder in a vacuum environment, heating the amorphous graphite powder to 600-1000 DEG C, and keeping the temperature for 4-6 hours; and (3) naturally cooling the amorphous graphite powder treated in the step (2) to room temperature to obtain the modified amorphous graphite. The friction material adopts the modified amorphous graphite as a friction performance regulator, the crystallinity of the modified amorphous graphite is increased, and the wear resistance is improved, 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 present application relates to the technical field of friction materials, and in particular to a friction material using modified earthy graphite as a friction performance regulator, a preparation method and an application thereof. Background Art

[0002] Friction material is a component material used in power machinery that relies on friction to perform braking and transmission functions. Friction material is usually a composite material formed by hot pressing and other means in a mold through multiple components such as polymer binders, reinforcing fiber materials, friction performance modifiers, and fillers. Friction performance modifiers can adjust the friction coefficient of friction materials and further adjust the friction performance of friction materials; at the same time, as an important component of friction materials, friction performance modifiers can also adjust the overall wear resistance of friction materials. Friction materials are usually used in the automotive industry to make key safety components such as brake pads. Their functional status is self-evident. In practical applications, it is necessary to take into account both the friction coefficient and wear resistance of friction materials.

[0003] Flake graphite is thin and tough, with excellent physical and chemical properties. Natural flake graphite has a low friction coefficient, the best lubricity, the highest plasticity, and strong wear resistance. It is one of the most common friction performance regulators for friction materials. However, in the field of automobile brake pad production, the content of flake graphite in friction materials is difficult to adjust. Too high a content will cause the friction coefficient of the friction material to drop sharply, leading to brake failure and safety accidents; too low a content will lead to insufficient wear resistance of the friction material, resulting in rapid wear of the produced brake pads, short service life, high safety risks, and high replacement costs.

[0004] Therefore, making low-cost friction materials with stable friction coefficient and high wear resistance has become a difficulty to be solved. Summary of the invention

[0005] In view of this, the purpose of this application is to provide a friction material, preparation method and application using modified earthy graphite as a friction performance regulator. Earthy graphite has a relatively stable friction coefficient. On this basis, this application modifies the earthy graphite to further improve the wear resistance of the earthy graphite. The friction material using modified earthy graphite as a friction performance regulator has the characteristics of a stable friction coefficient and high wear resistance, and is suitable for use in the manufacture of brake products such as automobile brake pads.

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

[0007] In a first aspect, the present application provides a friction material using modified earthy graphite as a friction performance modifier, which comprises the following components in parts by mass:

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

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

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

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

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

[0013] In a second aspect, the present application provides a method for preparing the aforementioned friction material, comprising the following steps:

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

[0015] (2) preparing phenolic resin, fiber reinforcement material, modified earthy graphite, and filler according to parts by mass, and mixing them 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) The friction material preform obtained in (3) is subjected to heat treatment to obtain a friction material having modified earthy graphite as a friction performance modifier.

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

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

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

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

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

[0023] Figure 1 The comparison diagrams of the friction material M3 before and after the AK Master experiment, where (a) to (d) are the front view, side view, front view and side view of the friction material M3 before and after the experiment, respectively.

[0024] Figure 2 The comparison diagram of the friction material M6 before and after the AK Master experiment, where (a) to (d) are the front view, side view, front view and side view of the friction material M6 before and after the experiment, respectively.

[0025] Figure 3 The comparison diagrams of the friction material M7 before and after the AK Master experiment, where (a) to (d) are the front view, side view, front view and side view of the friction material M7 before and after the experiment, respectively. DETAILED DESCRIPTION

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

[0027] Those skilled in the art will appreciate that, unless otherwise stated, the "said", "the", and "the aforementioned" used in the text of the present application may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present application means the presence of the features, steps, and operations, but does not exclude the presence or addition of one or more other features, integers, and steps.

[0028] Those skilled in the art will appreciate that, for any specific experimental steps or conditions not specified in the examples, the experiments may be carried out according to the conventional experimental steps or conditions described in the literature in the art; any raw materials or instruments used without specifying the manufacturer are conventional products that can be purchased commercially.

[0029] Those skilled in the art will understand that, unless otherwise specified in the present application, when a numerical range is given in an embodiment, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application are consistent with the prior art mastery of those skilled in the art and the records of this application, and any methods, equipment and materials of the prior art similar or equivalent to the methods, equipment and materials described in the embodiments of this application may also be used to implement this application.

[0030] Existing friction materials mostly use flake graphite as a friction performance regulator, but this type of friction material often cannot have both high wear resistance and a stable friction coefficient. Using this type of friction material to prepare automotive brake products, such as brake pads, poses safety risks and high replacement costs. Earthy graphite has a high source, lower cost than flake graphite, and a relatively stable friction coefficient, but lower wear resistance than flake graphite. The applicant has found through research that the modified earthy graphite obtained by grinding and heat treating earthy graphite has significantly improved wear resistance. On this basis, the embodiment of the present application uses modified earthy graphite as a friction performance regulator to prepare a new friction material. It has been verified that compared with existing friction materials, this friction material has good wear resistance and a stable friction coefficient, and is suitable for preparing brake products such as automotive brake pads.

[0031] Based on this, the embodiment of the present application provides a friction material using modified earthy graphite as a friction performance regulator, which includes the following components by mass: 13 to 18 parts of phenolic resin, 17 to 23 parts of fiber reinforcement material, 5 to 15 parts of modified earthy graphite, and 40 to 60 parts of filler; the modified earthy graphite is prepared by the following method:

[0032] (1) crushing and grinding the earthy graphite, passing it through a 100-300 mesh sieve to obtain earthy graphite powder;

[0033] (2) placing the earthy graphite powder in a vacuum environment, heating it to 600-1000° C., and maintaining it 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 is used as a binder, and its solidification provides a rigid structure for the friction material, making the friction material easy to shape and tightly combining other components; the fiber reinforcement material enables the friction material to have strong tensile and bending strength; the modified earthy graphite is used 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 and enhance the structural strength of the friction material. At the same time, without affecting the performance of the friction material, it reduces the use of expensive materials and reduces the production cost of the friction material.

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

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

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

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

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

[0041] In certain embodiments, in step (2) of preparing modified earthy graphite, the heating rate is 10° C. / min.

[0042] Based on this, an embodiment of the present application provides a method for preparing the aforementioned friction material, comprising the following steps: (1) preparing modified earthy graphite according to the aforementioned method; (2) preparing phenolic resin, fiber reinforcement material, modified earthy graphite, and filler according to mass parts, and mixing them 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.

[0043] In certain embodiments, during 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 certain embodiments, during the heat treatment 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 application of the aforementioned friction material in the preparation of brake pads.

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

[0047] Example 1

[0048] This embodiment provides a method for preparing a friction material using modified earthy graphite as a friction performance modifier, and the specific steps are as follows:

[0049] (1) obtaining 100 mesh modified earthy graphite powder according to the above method;

[0050] (2) Take 16 parts of phenolic resin, 10 parts of mineral wool fiber, 10 parts of glass fiber, 5 parts of modified earthy graphite, and 52 parts of barium sulfate by mass, mix and stir for 15 minutes to obtain a friction material premix, which is set aside;

[0051] (3) Weigh 220 g of the friction material obtained in (2) and pour it into a 85 mm × 85 mm hot pressing mold, and perform hot pressing molding under the conditions of a temperature of 130° C. and a pressure of 20 MPa for 20 min to obtain a friction material preform;

[0052] (4) The friction material preform obtained in (3) is placed in a muffle furnace for heat treatment at a temperature of 150° C. for a time of 6 h, and then naturally cooled to room temperature to obtain a friction material M1 having modified earthy graphite as a friction performance regulator.

[0053] Example 2

[0054] This embodiment provides a method for preparing a friction material using modified earthy graphite as a friction performance modifier, and the specific steps are as follows:

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

[0056] (2) Take 16 parts of phenolic resin, 10 parts of mineral wool fiber, 10 parts of glass fiber, 7 parts of modified earthy graphite, and 52 parts of barium sulfate by mass, mix and stir for 15 minutes to obtain a friction material premix, which is set aside;

[0057] (3) Weigh 220 g of the friction material obtained in (2) and pour it into a 85 mm × 85 mm hot pressing mold, and perform hot pressing molding under the conditions of a temperature of 130° C. and a pressure of 20 MPa for 20 min to obtain a friction material preform;

[0058] (4) The friction material preform obtained in (3) is placed in a muffle furnace for heat treatment at a temperature of 150° C. for a time of 6 h, and then naturally cooled to room temperature to obtain a friction material M2 having modified earthy graphite as a friction performance regulator.

[0059] Example 3

[0060] This embodiment provides a method for preparing a friction material using modified earthy graphite as a friction performance modifier, and the specific steps are as follows:

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

[0062] (2) Take 16 parts of phenolic resin, 10 parts of mineral wool fiber, 10 parts of glass fiber, 9 parts of modified earthy graphite, and 52 parts of barium sulfate by mass, mix and stir for 15 minutes to obtain a friction material premix, which is set aside;

[0063] (3) Weigh 220 g of the friction material obtained in (2) and pour it into a 85 mm × 85 mm hot pressing mold, and perform hot pressing molding under the conditions of a temperature of 130° C. and a pressure of 20 MPa for 20 min to obtain a friction material preform;

[0064] (4) The friction material preform obtained in (3) is placed in a muffle furnace for heat treatment at a temperature of 150° C. for a time of 6 h, and then naturally cooled to room temperature to obtain friction material M3 with modified earthy graphite as a friction performance regulator.

[0065] Example 4

[0066] This embodiment provides a method for preparing a friction material using modified earthy graphite as a friction performance modifier, and the specific steps are as follows:

[0067] (1) obtaining 100 mesh modified earthy graphite powder according to the above method;

[0068] (2) Take 16 parts of phenolic resin, 10 parts of mineral wool fiber, 10 parts of glass fiber, 13 parts of modified earthy graphite, and 52 parts of barium sulfate by mass, mix and stir for 15 minutes to obtain a friction material premix, which is set aside;

[0069] (3) Weigh 220 g of the friction material obtained in (2) and pour it into a 85 mm × 85 mm hot pressing mold, and perform hot pressing molding under the conditions of a temperature of 130° C. and a pressure of 20 MPa for 20 min to obtain a friction material preform;

[0070] (4) The friction material preform obtained in (3) is placed in a muffle furnace for heat treatment at a temperature of 150° C. for a time of 6 h, and then naturally cooled to room temperature to obtain friction material M4 with modified earthy graphite as a friction performance regulator.

[0071] Example 5

[0072] This embodiment provides a method for preparing a friction material using modified earthy graphite as a friction performance modifier, and the specific steps are as follows:

[0073] (1) obtaining 100 mesh modified earthy graphite powder according to the above method;

[0074] (2) Take 16 parts of phenolic resin, 10 parts of mineral wool fiber, 10 parts of glass fiber, 15 parts of modified earthy graphite, and 52 parts of barium sulfate, and mix and stir for 15 minutes to obtain a friction material premix, which is set aside;

[0075] (3) Weigh 220 g of the friction material obtained in (2) and pour it into a 85 mm × 85 mm hot pressing mold, and perform hot pressing molding under the conditions of a temperature of 130° C. and a pressure of 20 MPa for 20 min to obtain a friction material preform;

[0076] (4) The friction material preform obtained in (3) is placed in a muffle furnace for heat treatment at a temperature of 150° C. for a time of 6 h, and then naturally cooled to room temperature to obtain friction material M5 with modified earthy graphite as a friction performance regulator.

[0077] Example 6

[0078] This embodiment provides a method for preparing a friction material using modified earthy graphite as a friction performance modifier, and the specific steps are as follows:

[0079] (1) obtaining 200-mesh modified earthy graphite powder according to the aforementioned method;

[0080] (2) Take 16 parts of phenolic resin, 10 parts of mineral wool fiber, 10 parts of glass fiber, 9 parts of modified earthy graphite, and 52 parts of barium sulfate by mass, mix and stir for 15 minutes to obtain a friction material premix, which is set aside;

[0081] (3) Weigh 220 g of the friction material obtained in (2) and pour it into a 85 mm × 85 mm hot pressing mold, and perform hot pressing molding under the conditions of a temperature of 130° C. and a pressure of 20 MPa for 20 min to obtain a friction material preform;

[0082] (4) The friction material preform obtained in (3) is placed in a muffle furnace for heat treatment at a temperature of 150° C. for a time of 6 h, and then naturally cooled to room temperature to obtain friction material M6 with modified earthy graphite as a friction performance regulator.

[0083] Example 7

[0084] This embodiment provides a method for preparing a friction material using modified earthy graphite as a friction performance modifier, and the specific steps are as follows:

[0085] (1) obtaining 300-mesh modified earthy graphite powder according to the aforementioned method;

[0086] (2) Take 16 parts of phenolic resin, 10 parts of mineral wool fiber, 10 parts of glass fiber, 9 parts of modified earthy graphite, and 52 parts of barium sulfate by mass, mix and stir for 15 minutes to obtain a friction material premix, which is set aside;

[0087] (3) Weigh 220 g of the friction material obtained in (2) and pour it into a 85 mm × 85 mm hot pressing mold, and perform hot pressing molding under the conditions of a temperature of 130° C. and a pressure of 20 MPa for 20 min to obtain a friction material preform;

[0088] (4) The friction material preform obtained in (3) is placed in a muffle furnace for heat treatment at a temperature of 150° C. for a time of 6 h, and then naturally cooled to room temperature to obtain friction material M7 with modified earthy graphite as a friction performance regulator.

[0089] Comparative Example 1

[0090] This comparative example provides a method for preparing a friction material, and the specific steps are as follows:

[0091] (1) obtaining 100 mesh modified earthy graphite powder according to the above method;

[0092] (2) Take 16 parts of phenolic resin, 10 parts of mineral wool fiber, 10 parts of glass fiber, 4 parts of modified earthy graphite, and 52 parts of barium sulfate by mass, mix and stir for 15 minutes to obtain a friction material premix, which is set aside;

[0093] (3) Weigh 220 g of the friction material obtained in (2) and pour it into a 85 mm × 85 mm hot pressing mold, and perform hot pressing molding under the conditions of a temperature of 130° C. and a pressure of 20 MPa for 20 min to obtain a friction material preform;

[0094] (4) The friction material preform obtained in (3) was placed in a muffle furnace for heat treatment at a temperature of 150° C. for 6 h, and then naturally cooled to room temperature to obtain friction material M8.

[0095] Comparative Example 2

[0096] This comparative example provides a method for preparing a friction material, and the specific steps are as follows:

[0097] (1) obtaining 100 mesh modified earthy graphite powder according to the above method;

[0098] (2) Take 16 parts of phenolic resin, 10 parts of mineral wool fiber, 10 parts of glass fiber, 16 parts of modified earthy graphite, and 52 parts of barium sulfate by mass, mix and stir for 15 minutes to obtain a friction material premix, which is set aside;

[0099] (3) Weigh 220 g of the friction material obtained in (2) and pour it into a 85 mm × 85 mm hot pressing mold, and perform hot pressing molding under the conditions of a temperature of 130° C. and a pressure of 20 MPa for 20 min to obtain a friction material preform;

[0100] (4) The friction material preform obtained in (3) was placed in a muffle furnace for heat treatment at a temperature of 150° C. for 6 h, and then naturally cooled to room temperature to obtain friction material M9.

[0101] Comparative Example 3

[0102] This comparative example provides a method for preparing a friction material, and the specific steps are as follows:

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

[0104] (2) Weigh 220 g of the friction material obtained in (1) and pour it into a 85 mm × 85 mm hot pressing mold, and perform hot pressing molding under the conditions of a temperature of 130° C. and a pressure of 20 MPa for 20 min to obtain a friction material preform;

[0105] (3) The friction material preform obtained in (2) was placed in a muffle furnace for heat treatment at a temperature of 150° C. for 6 h, and then naturally cooled to room temperature to obtain friction material M10.

[0106] Comparative Example 4

[0107] This comparative example provides a method for preparing a friction material, and the specific steps are as follows:

[0108] (1) Take 16 parts of phenolic resin, 10 parts of mineral wool fiber, 10 parts of glass fiber, 9 parts of flake graphite, and 52 parts of barium sulfate by mass, mix and stir for 15 minutes to obtain a friction material premix, which is set aside;

[0109] (2) Weigh 220 g of the friction material obtained in (1) and pour it into a 85 mm × 85 mm hot pressing mold, and perform hot pressing molding under the conditions of a temperature of 130° C. and a pressure of 20 MPa for 20 min to obtain a friction material preform;

[0110] (3) The friction material preform obtained in (2) was placed in a muffle furnace for heat treatment at a temperature of 150° C. for 6 h, and then naturally cooled to room temperature to obtain friction material M11.

[0111] Comparative Example 5

[0112] This comparative example provides a method for preparing a friction material, and the specific steps are as follows:

[0113] (1) Take 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 by mass, mix and stir for 15 minutes to obtain a friction material premix, and set aside;

[0114] (2) Weigh 220 g of the friction material obtained in (1) and pour it into a 85 mm × 85 mm hot pressing mold, and perform hot pressing molding under the conditions of 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 at a temperature of 150° C. for 6 h, and then naturally cooled to room temperature to obtain friction material M12.

[0116] Comparative Example 6

[0117] This comparative example provides a method for preparing a friction material, and the specific steps are as follows:

[0118] (1) Take 16 parts of phenolic resin, 10 parts of mineral wool fiber, 10 parts of glass fiber, 9 parts of unmodified earthy graphite, and 52 parts of barium sulfate, and mix and stir for 15 minutes to obtain a friction material premix, which is set aside;

[0119] (2) Weigh 220 g of the friction material obtained in (1) and pour it into a 85 mm × 85 mm hot pressing mold, and perform hot pressing molding under the conditions of 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 (2) was placed in a muffle furnace for heat treatment at a temperature of 150° C. for 6 h, and then naturally cooled to room temperature to obtain friction material M13.

[0121] The friction properties of the friction materials M1 to M13 prepared above were tested according to the AK Master standard. The test items included wear thickness and friction coefficient to consider the wear resistance and friction coefficient stability of each friction material. The test results are shown in Table 1 below:

[0122] Table 1

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

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

[0125] By analyzing 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 regulator in M13 is unmodified earthy graphite. Although the friction coefficient meets the requirements, the wear resistance is poor.

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

[0127] The wear resistance of the friction materials M3, M6 and M7 prepared in Examples 3, 6 and 7 in Table 1 was analyzed, and it was found that M3 was better than M6 and M7, indicating that the modified earthy graphite, when used as a friction material regulator, also affects the wear resistance of the final friction material. When the mesh number of the modified earthy graphite powder is 100, the wear resistance of the prepared friction material is the best. Figures 1 to 3 The actual comparison pictures of friction materials M3, M6 and M7 before and after AK Master experiment.

[0128] By analyzing the average wear thickness and friction coefficient data of friction materials M10, M11, and M12 prepared in Comparative Examples 3 to 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 proportion of flake graphite is increased, although the wear resistance is improved, the average friction coefficient shows a sharp downward trend. When the mass proportion of flake graphite is 9 parts, the average friction coefficient is lower than 0.2, and the braking safety is low. If the friction material is used to manufacture automobile brake pads, it is difficult to take into account both wear resistance and a suitable friction coefficient.

[0129] In summary, the friction material prepared in the embodiment of the present application using modified earthy graphite as a friction performance regulator has high wear resistance and a stable friction coefficient, and can replace flake graphite for manufacturing friction materials and other products, thereby reducing production costs.

[0130] The present application is described in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the present application and its core ideas. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A friction material using modified earthy graphite as a friction performance modifier, characterized in that: The invention comprises the following components by weight: 13 to 18 parts of phenolic resin, 17 to 23 parts of fiber reinforcement material, 5 to 15 parts of modified earthy graphite, and 40 to 60 parts of filler; the modified earthy graphite is prepared by the following method: (1) crushing and grinding the earthy graphite, passing it through a 100-300 mesh sieve to obtain earthy graphite powder; (2) placing the earthy graphite powder in a vacuum environment, heating it to 600-1000° C., and maintaining it for 4-6 hours; (3) The earthy graphite powder treated in (2) is naturally cooled to room temperature to obtain the modified earthy graphite.

2. The friction material according to claim 1, characterized in that: The fiber reinforcement material is at least one of mineral wool fiber and glass fiber.

3. The friction material according to claim 1, characterized in that: The fiber reinforcement material is mineral wool fiber or glass fiber.

4. The friction material according to claim 1, characterized in that: The filler is at least one of barium sulfate, heavy calcium carbonate and vermiculite powder.

5. The friction material according to claim 1, characterized in that: The fiber reinforcement material is mineral wool fiber and glass fiber, and the filler is barium sulfate. The friction material includes the following components by mass: 16 parts of phenolic resin, 10 parts of mineral wool fiber, 10 parts of glass fiber, 7-13 parts of modified earthy graphite, and 52 parts of barium sulfate.

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

7. The method for preparing the friction material according to claim 1, characterized in that: The following steps are involved: (1) preparing modified earthy graphite; (2) preparing phenolic resin, fiber reinforcement material, modified earthy graphite, and filler according to parts by mass, and mixing them to form a friction material premix; (3) hot pressing the friction material premix obtained in (2) to obtain a friction material preform; (4) The friction material preform obtained in (3) is subjected to heat treatment to obtain a friction material having modified earthy graphite as a friction performance modifier.

8. The preparation method according to claim 7, characterized in that: (3) During the hot pressing process, 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.

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

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

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