Brake pad friction material, brake pad and preparation method of brake pad

Abstract

The invention provides a brake pad friction material, a brake pad and a preparation method of the brake pad, and relates to the technical field of automobile friction brake materials. The friction material is prepared from, by weight, 3-8 parts of modified thermosetting phenolic resin, 5-9 parts of modified thermoplastic phenolic resin, 3-6 parts of aramid fiber, 7-10 parts of modified potassium titanate, 2-5 parts of stannous sulfide, 2-5 parts of synthetic graphite, 6-15 parts of mineral fiber, 6-11 parts of iron oxide red, 7-10 parts of silica powder, 2-5 parts of friction powder, 5-10 parts of kaolin, 5-8 parts of zinc-aluminum alloy fiber, 3-8 parts of steel fiber, 5-8 parts of magnesium oxide and 10-15 parts of zirconium silicate. The components of the friction material have a synergistic effect, so that the friction material has a stable friction coefficient, excellent heat conductivity and relatively low abrasion loss, and no open fire is generated under a high-speed continuous braking working condition.

Description

Technical Field

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

[0002] In recent years, driven by the global trend of the automotive industry's transition to new energy, the overall architecture of electric vehicles has undergone significant changes. Compared to traditional fuel-powered vehicles, the weight of electric vehicles of the same class has increased significantly due to the installation of power battery packs, resulting in a significant increase in braking inertia. Under existing technology, the maximum brake pad temperature exceeds 700°C at speeds exceeding 140 km / h, and exceeds 750°C at speeds exceeding 150 km / h. This increase in vehicle mass places higher demands on the braking performance of the friction brake system, particularly in terms of thermal fade control under high-speed continuous braking conditions. Summary of the Invention

[0003] In view of the above problems existing in the prior art, the present invention provides a brake pad friction material and a brake pad and a preparation method thereof, so as to improve the braking performance of the brake pad under high-speed continuous braking conditions.

[0004] To achieve the above-mentioned object and other related objects, the first aspect of the present invention provides a brake pad friction material, which is composed of the following components in parts by weight: 3-8 parts of modified thermosetting phenolic resin, 5-9 parts of modified thermoplastic phenolic resin, 3-6 parts of aramid, 7-10 parts of modified potassium titanate, 2-5 parts of stannous sulfide, 2-5 parts of synthetic graphite, 6-15 parts of mineral fiber, 6-11 parts of red iron oxide, 7-10 parts of silicon micropowder, 2-5 parts of friction powder, 5-10 parts of kaolin, 5-8 parts of zinc-aluminum alloy fiber, 3-8 parts of steel fiber, 5-8 parts of magnesium oxide, and 10-15 parts of zirconium silicate.

[0005] In one embodiment of the present invention, the modified thermosetting phenolic resin is a cashew nut shell liquid modified thermosetting phenolic resin.

[0006] In one embodiment of the present invention, the modified thermoplastic phenolic resin is a silicon-modified thermoplastic phenolic resin, and the fluidity of the modified thermoplastic phenolic resin at 125° C. is 60-90 mm.

[0007] In one embodiment of the present invention, the modified potassium titanate is graphite surface-modified potassium titanate.

[0008] In one embodiment of the present invention, the synthetic graphite is thermally modified synthetic graphite, the degree of graphitization of the synthetic graphite is 85-100%, and the synthetic graphite is a single-layer flake structure.

[0009] In one embodiment of the present invention, the mineral fiber is a thermally modified mineral fiber, and the thermal conductivity of the thermally modified mineral fiber is 0.4 to 0.8 W / (m·K).

[0010] A second aspect of the present invention provides a brake pad, comprising a steel back and a friction block made of the above-mentioned friction material, wherein the steel back is fixedly connected to the friction block.

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

[0012] Weighing and uniformly mixing modified thermoplastic phenolic resin, aramid, modified potassium titanate, stannous sulfide, synthetic graphite, mineral fiber, red iron oxide, silicon powder, friction powder, kaolin, zinc-aluminum alloy fiber, steel fiber, magnesium oxide, and zirconium silicate according to a proportion to obtain a solid mixture;

[0013] placing the solid mixture and the modified thermosetting phenolic resin in an internal mixer to obtain granular material;

[0014] Placing the granular material and the steel back in a hot pressing mold cavity for hot pressing;

[0015] The hot-pressed product is demoulded and heat-treated to obtain the brake pad.

[0016] In one embodiment of the present invention, during hot pressing, the pressing temperature is 135-155° C., the hot pressing pressure is 12-20 MPa, and the hot pressing time is 300-600 s.

[0017] In one embodiment of the present invention, during heat treatment, the product after demolding by hot pressing is first baked at a temperature of 180-200° C. for 1-3 hours under a clamping force of 10-20 kN, and then baked at a temperature of 200-220° C. for 3-6 hours.

[0018] The brake pad friction material of the present invention does not contain non-environmentally friendly components such as copper and antimony sulfide. The friction block made of it uses modified thermosetting phenolic resin and modified thermoplastic phenolic resin as adhesives, modified potassium titanate, red iron oxide, magnesium oxide and zirconium silicate as friction performance regulators, and steel fiber, zinc-aluminum alloy fiber and mineral fiber as reinforcing fibers. By regulating the ratio between the various components, the components play a synergistic role, so that the friction block has a stable friction coefficient, excellent thermal conductivity and low wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 FIG. 1 is a flow chart of the preparation of a brake pad according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the 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 the following examples and the features in the examples can be combined with each other unless they conflict. It should also be understood that the terms used in the examples of the present invention are for the purpose of describing specific embodiments, not for the purpose of limiting the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0022] When numerical ranges are given in the examples, it should be understood that unless otherwise specified herein, both endpoints of each numerical range and any value between the two endpoints may be used. Unless otherwise defined, all technical and scientific terms used herein are consistent with the prior art as understood by those skilled in the art and the description of the present invention. Any prior art methods, devices, and materials similar or equivalent to those in the examples of the present invention may 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 description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0024] The present invention provides a brake pad friction material, which is characterized in that the friction material consists of the following components in parts by weight: 3-8 parts of modified thermosetting phenolic resin, 5-9 parts of modified thermoplastic phenolic resin, 3-6 parts of aramid, 7-10 parts of modified potassium titanate, 2-5 parts of stannous sulfide, 2-5 parts of synthetic graphite, 6-15 parts of mineral fiber, 6-11 parts of red iron oxide, 7-10 parts of silicon micropowder, 2-5 parts of friction powder, 5-10 parts of kaolin, 5-8 parts of zinc-aluminum alloy fiber, 3-8 parts of steel fiber, 5-8 parts of magnesium oxide, and 10-15 parts of zirconium silicate.

[0025] In one embodiment, the modified thermosetting phenolic resin is a cashew nut shell liquid modified thermosetting phenolic resin.

[0026] In one embodiment, the modified thermoplastic phenolic resin is a silicon-modified thermoplastic phenolic resin, and the modified thermoplastic phenolic resin has a fluidity of 60 to 90 mm at 125° C., and a gel time of 55 to 95 seconds at 150° C. The flow distance and gel time of the silicon-modified thermoplastic phenolic resin are measured in accordance with Appendices A2 and A4 of GB / T 24411-2009.

[0027] In one embodiment, the modified potassium titanate is graphite surface-modified potassium titanate.

[0028] In one embodiment, the degree of graphitization of the synthetic graphite is 85-100%, and the synthetic graphite has a single-layer flake structure.

[0029] In one embodiment, the mineral fiber is a thermally modified mineral fiber, and the thermally modified mineral fiber has a thermal conductivity of 0.4 to 0.8 W / (m·K). For example, the thermally modified mineral fiber is produced by modifying the fiber surface with a coupling agent. The coupling agent reacts with functional groups on the fiber surface to enhance the bonding between the fiber and the resin matrix, thereby improving thermal conductivity and mechanical strength.

[0030] In one embodiment, the length of the mineral fiber is 0.3-0.7 mm, the length of the zinc-aluminum alloy fiber is 0.6-0.9 mm, the length of the steel fiber is 0.3-0.9 mm, and the length of the aramid fiber is 90-135 mm. For example, based on the mass percentage of the zinc-aluminum alloy, the mass percentage of zinc in the zinc-aluminum alloy fiber is 85% and the mass percentage of aluminum is 15%.

[0031] In one embodiment, the particle size of synthetic graphite is 30-100 mesh, the particle size of silica powder is 325-800 mesh, the particle size of friction powder is 40-325 mesh, the particle size of magnesium oxide is 100-200 mesh, and the particle size of red iron oxide is 800-1000 mesh. For example, when screening the particle sizes of the components, a small-mesh sieve is placed on top and a large-mesh sieve is placed on the bottom. The component between the two sieves is the component with the desired particle size. Kaolin passes through a 325-mesh sieve. Zirconium silicate passes through a 2000-mesh sieve. For example, the friction powder is made from cashew nut shell liquid.

[0032] The present invention also provides a brake pad comprising a steel backing and a friction block made of the aforementioned friction material, the steel backing being fixedly connected to the friction block. The brake pad of the present invention, through the synergistic effect between the various components of the friction material, exhibits excellent thermal conductivity, a stable coefficient of friction, and low wear. It is also less likely to generate flames under high-temperature braking, significantly extending the service life of the brake pad.

[0033] The brake pad friction material of the present invention does not contain non-environmentally friendly components such as copper and antimony sulfide. The friction block made of it uses modified thermosetting phenolic resin and modified thermoplastic phenolic resin as adhesives, modified potassium titanate, red iron oxide, magnesium oxide and zirconium silicate as friction performance regulators, and steel fiber, zinc-aluminum alloy fiber and mineral fiber as reinforcing fibers. By regulating the ratio between the various components, the components play a synergistic role, so that the friction block has a stable friction coefficient, excellent thermal conductivity and low wear.

[0034] Furthermore, the modified thermoplastic phenolic resin of the present invention uses silicon-modified thermoplastic phenolic resin, so that the friction block has excellent wear resistance under high-temperature braking conditions. The synthetic graphite uses heat-modified highly graphitized synthetic graphite, and the modified potassium titanate uses graphite surface-modified potassium titanate. The synthetic graphite and modified potassium titanate are evenly distributed in the friction material, which can construct special graphite channels and produce a bridging effect for heat transfer, greatly improving the thermal conductivity of the friction block, so that the friction block has excellent friction performance under harsh high-temperature conditions. High-purity stannous sulfide is selected as a friction modifier. Stannous sulfide belongs to the cubic crystal system and has excellent lubrication properties, which makes the friction block have a longer life. Magnesium oxide and zirconium silicate are selected as friction-increasing components. By combining magnesium oxide and zirconium silicate and adjusting the particle size of magnesium oxide and zirconium silicate, the friction block has a higher friction coefficient under different braking conditions. Kaolin can adjust and stabilize the friction coefficient of friction materials, so that it can maintain a stable friction coefficient under different working conditions, thereby improving the braking performance of the vehicle. At the same time, kaolin can also absorb heat during braking and reduce the decrease in friction coefficient caused by high temperature.

[0035] The present invention also provides a method for preparing a brake pad, comprising the following steps:

[0036] S1. Weighing and uniformly mixing modified thermoplastic phenolic resin, aramid, modified potassium titanate, stannous sulfide, synthetic graphite, mineral fiber, red iron oxide, silicon powder, friction powder, kaolin, zinc-aluminum alloy fiber, steel fiber, magnesium oxide, and zirconium silicate according to a proportion to obtain a solid mixture;

[0037] S2, placing the solid mixture and the modified thermosetting phenolic resin in an internal mixer to obtain a granular material;

[0038] S3, placing the granular material and the steel back in a hot pressing mold cavity for hot pressing;

[0039] S4. Heat-treating the hot-pressed product to obtain a brake pad.

[0040] In step S1, the weight proportions of the components in the solid mixture are as follows: 5-9 parts of modified thermoplastic phenolic resin, 3-6 parts of aramid, 7-10 parts of modified potassium titanate, 2-5 parts of stannous sulfide, 2-5 parts of synthetic graphite, 6-15 parts of mineral fiber, 6-11 parts of red iron oxide, 7-10 parts of silicon micropowder, 2-5 parts of friction powder, 5-10 parts of kaolin, 5-8 parts of zinc-aluminum alloy fiber, 3-8 parts of steel fiber, 5-8 parts of magnesium oxide, and 10-15 parts of zirconium silicate.

[0041] In step S2, the modified thermosetting phenolic resin is added in an amount of 3 to 8 parts by weight. The weight of one part of the modified thermosetting phenolic resin is equal to the weight of one part of each component in step S1. In one embodiment, after banburying the solid mixture and the modified thermosetting phenolic resin, the process further includes crushing the resulting particles. Exemplarily, the particle size of the particles is 40 to 60 mesh.

[0042] In step S3, during hot pressing, the pressing temperature is 135-155°C, for example, 135°C, 145°C, or 155°C. The hot pressing pressure is 12-20 MPa, for example, 12 MPa, 15 MPa, or 20 MPa. The hot pressing time is 300-600 seconds, for example, 300 seconds, 400 seconds, 500 seconds, or 600 seconds. The granular material is formed into a friction block through hot pressing. The friction block is located on one side of the steel backing in the thickness direction and is bonded to the steel backing.

[0043] In step S4, the hot-pressed product, after demolding, is subjected to a baking process. In some embodiments, a clamping device is used to clamp the hot-pressed product to enhance the bonding strength between the friction material and the steel backing. Exemplarily, the clamping force is 10 to 20 kN, for example, 10 kN, 15 kN, or 20 kN, or any other value within the range. The baking process includes a first baking process and a second baking process. The first baking process is performed at a temperature of 180 to 200°C, for example, 180°C, 190°C, or 200°C, for a duration of 1 to 3 hours, for example, 1 hour, 2 hours, or 3 hours. The second baking process is performed at a temperature of 200 to 220°C, for example, 200°C, 210°C, or 220°C, for a duration of 3 to 6 hours, for example, 3 hours, 5 hours, or 6 hours, or any other value within the range.

[0044] In some embodiments, after the hot-pressed product is demolded and heat-treated, the method for preparing the brake pad further includes post-processing processes such as grinding, grooving, chamfering, and spraying.

[0045] The preparation method of the brake pad of the present invention has simple process, convenient operation, and pollution-free preparation process, which is beneficial to optimizing the working environment of operators.

[0046] The technical solutions of the present invention are described in detail below through several specific examples. Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by conventional methods in the art, and the instruments used in the examples are all commercially available.

[0047] Example 1

[0048] The preparation method of the brake pad in this embodiment is as follows: (1) according to the proportion of 9 parts of modified thermoplastic phenolic resin, 6 parts of aramid, 10 parts of modified potassium titanate, 2 parts of stannous sulfide, 4 parts of synthetic graphite, 15 parts of mineral fiber, 7 parts of red iron oxide, 7 parts of silicon micropowder, 5 parts of friction powder, 7 parts of kaolin, 5 parts of zinc-aluminum alloy fiber, 5 parts of steel fiber, 5 parts of magnesium oxide, and 10 parts of zirconium silicate, the components are weighed and placed in a plowshare mixer and mixed and stirred for 12 minutes to obtain a solid mixture; (2) the modified thermosetting phenolic resin is weighed and the mixture is stirred and mixed to obtain a solid mixture; 3 parts, and the modified thermosetting phenolic resin and the solid mixture are placed in an internal mixer for internal mixing to obtain granular material; (3) the granular material is placed in the cavity of a hot pressing mold and a steel back is placed, and pressed at a temperature of 155°C and a pressure of 15 MPa for 500s; (4) the hot-pressed product is demoulded and baked at a temperature of 180°C for 3h under a clamping force of 10kN, and then baked at a temperature of 200°C for 6h for heat treatment; (5) after the heat treatment is completed, the product is ground, grooved, chamfered, and sprayed to obtain a brake pad. In this embodiment, the modified thermosetting phenolic resin is a cashew nut shell oil-modified thermosetting phenolic resin, the modified thermoplastic phenolic resin is a silicon-modified thermoplastic phenolic resin, the fluidity of the modified thermoplastic phenolic resin at 125°C is 60 mm, the modified potassium titanate is graphite surface-modified potassium titanate, the synthetic graphite is heat-modified synthetic graphite, the degree of graphitization of the synthetic graphite is 95%, the synthetic graphite is a single-layer flake structure, the mineral fiber is a heat-modified mineral fiber, and the thermal conductivity of the heat-modified mineral fiber is 0.6 W / (m·K).

[0049] Example 2

[0050] The preparation method of the brake pad in this embodiment is as follows: (1) according to the proportion of 5 parts of modified thermoplastic phenolic resin, 4 parts of aramid, 7 parts of modified potassium titanate, 5 parts of stannous sulfide, 2 parts of synthetic graphite, 6 parts of mineral fiber, 11 parts of red iron oxide, 10 parts of silicon powder, 2 parts of friction powder, 10 parts of kaolin, 5 parts of zinc-aluminum alloy fiber, 5 parts of steel fiber, 8 parts of magnesium oxide, and 11 parts of zirconium silicate, the components are weighed and placed in a plowshare mixer and mixed and stirred for 12 minutes to obtain a solid mixture; (2) the modified thermosetting phenolic resin is weighed and the mixture is stirred and mixed to obtain a solid mixture; 6 parts, and the modified thermosetting phenolic resin and the solid mixture are placed in an internal mixer for internal mixing to obtain granular material; (3) the granular material is placed in the cavity of a hot pressing mold and a steel back is placed, and pressed at a temperature of 145°C and a pressure of 15 MPa for 500s; (4) the hot-pressed product is demoulded and baked at a temperature of 180°C for 3h under a clamping force of 20kN, and then baked at a temperature of 200°C for 3h for heat treatment; (5) after the heat treatment is completed, the product is ground, grooved, chamfered, and sprayed to obtain a brake pad. In this embodiment, the modified thermosetting phenolic resin is a cashew nut shell oil-modified thermosetting phenolic resin, the modified thermoplastic phenolic resin is a silicon-modified thermoplastic phenolic resin, the fluidity of the modified thermoplastic phenolic resin at 125°C is 70 mm, the modified potassium titanate is graphite surface-modified potassium titanate, the synthetic graphite is heat-modified synthetic graphite, the degree of graphitization of the synthetic graphite is 85%, the synthetic graphite is a single-layer flake structure, the mineral fiber is a heat-modified mineral fiber, and the thermal conductivity of the heat-modified mineral fiber is 0.8 W / (m·K).

[0051] Example 3

[0052] The preparation method of the brake pad in this embodiment is as follows: (1) according to the proportion of 7 parts of modified thermoplastic phenolic resin, 5 parts of aramid, 8 parts of modified potassium titanate, 3 parts of stannous sulfide, 5 parts of synthetic graphite, 8 parts of mineral fiber, 6 parts of red iron oxide, 8 parts of silicon powder, 3 parts of friction powder, 5 parts of kaolin, 8 parts of zinc-aluminum alloy fiber, 3 parts of steel fiber, 7 parts of magnesium oxide, and 15 parts of zirconium silicate, the components are weighed and placed in a plowshare mixer and mixed and stirred for 12 minutes to obtain a solid mixture; (2) 8 parts of modified thermosetting phenolic resin are weighed and mixed and stirred to obtain a solid mixture; The modified thermosetting phenolic resin and the solid mixture are mixed in an internal mixer to obtain granular material; (3) the granular material is placed in the cavity of a hot pressing mold and a steel back is placed, and the granular material is pressed at a temperature of 135°C and a pressure of 15 MPa for 600 seconds; (4) the hot-pressed product is demoulded and baked at a temperature of 190°C for 3 hours and then baked at a temperature of 200°C for 5 hours under a clamping force of 15 kN for heat treatment; (5) after the heat treatment is completed, the product is ground, grooved, chamfered, and sprayed to obtain a brake pad. In this embodiment, the modified thermosetting phenolic resin is a cashew nut shell oil-modified thermosetting phenolic resin, the modified thermoplastic phenolic resin is a silicon-modified thermoplastic phenolic resin, the fluidity of the modified thermoplastic phenolic resin at 125°C is 90 mm, the modified potassium titanate is graphite surface-modified potassium titanate, the synthetic graphite is heat-modified synthetic graphite, the degree of graphitization of the synthetic graphite is 100%, the synthetic graphite is a single-layer flake structure, the mineral fiber is a heat-modified mineral fiber, and the thermal conductivity of the heat-modified mineral fiber is 0.4 W / (m·K).

[0053] Example 4

[0054] The preparation method of the brake pad in this embodiment is as follows: (1) according to the proportion of 6 parts of modified thermoplastic phenolic resin, 3 parts of aramid, 10 parts of modified potassium titanate, 4 parts of stannous sulfide, 5 parts of synthetic graphite, 13 parts of mineral fiber, 10 parts of red iron oxide, 8 parts of silicon micropowder, 5 parts of friction powder, 8 parts of kaolin, 6 parts of zinc-aluminum alloy fiber, 8 parts of steel fiber, 6 parts of magnesium oxide, and 13 parts of zirconium silicate, the components are weighed and placed in a plowshare mixer and mixed and stirred for 12 minutes to obtain a solid mixture; (2) the modified thermosetting phenolic resin is weighed and the mixture is stirred and mixed to obtain a solid mixture. 5 parts, and the modified thermosetting phenolic resin and the solid mixture are placed in an internal mixer for internal mixing to obtain granular material; (3) the granular material is placed in the cavity of a hot pressing mold and a steel back is placed, and pressed at a temperature of 145°C and a pressure of 20 MPa for 400s; (4) the hot-pressed product is demoulded and baked at a temperature of 200°C for 1h under a clamping force of 20kN, and then baked at a temperature of 220°C for 5h for heat treatment; (5) after the heat treatment is completed, the product is ground, grooved, chamfered, and sprayed to obtain a brake pad.

[0055] In this embodiment, the modified thermosetting phenolic resin is a cashew nut shell oil-modified thermosetting phenolic resin, the modified thermoplastic phenolic resin is a silicon-modified thermoplastic phenolic resin, the fluidity of the modified thermoplastic phenolic resin at 125°C is 80 mm, the modified potassium titanate is graphite surface-modified potassium titanate, the synthetic graphite is heat-modified synthetic graphite, the degree of graphitization of the synthetic graphite is 90%, the synthetic graphite is a single-layer flake structure, the mineral fiber is a heat-modified mineral fiber, and the thermal conductivity of the heat-modified mineral fiber is 0.7 W / (m·K).

[0056] Example 5

[0057] The preparation method of the brake pad in this embodiment is as follows: (1) according to the proportion of 6 parts of modified thermoplastic phenolic resin, 4 parts of aramid, 9 parts of modified potassium titanate, 2 parts of stannous sulfide, 3 parts of synthetic graphite, 10 parts of mineral fiber, 8 parts of red iron oxide, 7 parts of silicon powder, 2 parts of friction powder, 6 parts of kaolin, 7 parts of zinc-aluminum alloy fiber, 6 parts of steel fiber, 5 parts of magnesium oxide, and 15 parts of zirconium silicate, the components are weighed and placed in a plowshare mixer and mixed and stirred for 12 minutes to obtain a solid mixture; (2) 4 parts of modified thermosetting phenolic resin are weighed and mixed and stirred to obtain a solid mixture. The modified thermosetting phenolic resin and the solid mixture are mixed in an internal mixer to obtain granular material; (3) the granular material is placed in the cavity of a hot pressing mold and a steel back is placed, and the granular material is pressed at a temperature of 155°C and a pressure of 12 MPa for 300 seconds; (4) the hot-pressed product is demoulded and baked at a temperature of 200°C for 3 hours and then baked at a temperature of 210°C for 4 hours under a clamping force of 15 kN for heat treatment; (5) after the heat treatment is completed, the product is ground, grooved, chamfered, and sprayed to obtain a brake pad.

[0058] In this embodiment, the modified thermosetting phenolic resin is a cashew nut shell oil-modified thermosetting phenolic resin, the modified thermoplastic phenolic resin is a silicon-modified thermoplastic phenolic resin, the fluidity of the modified thermoplastic phenolic resin at 125°C is 70 mm, the modified potassium titanate is graphite surface-modified potassium titanate, the synthetic graphite is heat-modified synthetic graphite, the degree of graphitization of the synthetic graphite is 90%, the synthetic graphite is a single-layer flake structure, the mineral fiber is a heat-modified mineral fiber, and the thermal conductivity of the heat-modified mineral fiber is 0.7 W / (m·K).

[0059] In Examples 1 to 5, the particle size of the synthetic graphite was 30-100 mesh, the particle size of the silica powder was 325-800 mesh, the particle size of the friction powder was 40-325 mesh, the particle size of the magnesium oxide was 100-200 mesh, the particle size of the red iron oxide was 800-1000 mesh, and the zirconium silicate passed through a 2000 mesh sieve. Based on the mass percentage of the zinc-aluminum alloy, the mass percentage of zinc in the zinc-aluminum alloy fiber was 85% and the mass percentage of aluminum was 15%.

[0060] The brake pads prepared in Examples 1 to 5 were subjected to heat conduction tests and high-speed braking tests, respectively. The test method of the heat conduction test was in accordance with ISO 22007-2:2008 (E) standard. During the heat conduction test, four samples were taken from each example and their heat conduction coefficients were tested. The heat conduction coefficients of the four samples were averaged. The heat conduction coefficients of the brake pads are shown in Table 1. The high-speed braking test of the brake pads was carried out on a Link bench machine. The experimental steps were as follows: step 1: running-in at 80-0 km / h for 100 times; step 2: continuous braking at 135-0 km / h for 10 times; step 3: running-in at 80-0 km / h for 100 times; step 4: continuous braking at 135-0 km / h for 10 times. The friction coefficients of steps 2 and 4 were collected, and the test results are shown in Table 2. The wear of the brake pads after the high-speed braking test was tested, and the test results are shown in Table 3.

[0061] Table 1 Thermal conductivity of brake pads prepared in Examples 1 to 5 (W / (m·K))

[0062] Sample name Sample 1 Sample 2 Sample 3 Sample 4 average value Example 1 2.92 2.93 2.96 2.91 2.93 Example 2 2.48 2.54 2.59 2.49 2.525 Example 3 2.94 2.82 2.90 2.86 2.88 Example 4 3.25 3.36 3.31 3.29 3.30 Example 5 3.01 2.98 3.04 3.00 3.00

[0063] Table 2 Friction coefficient of brake pads prepared in Examples 1 to 5

[0064]

[0065]

[0066] Table 3 Wear of brake pads prepared in Examples 1 to 5

[0067]

[0068] Table 1 shows that the brake pads prepared in this application have good thermal conductivity. No open flames were generated during high-speed braking tests. Tables 2 and 3 show that the brake pads prepared in this application have good friction coefficient stability and minimal wear during high-speed braking tests.

[0069] The brake pad friction material of the present invention does not contain environmentally unfriendly components such as copper and antimony sulfide. The friction block manufactured from it uses modified thermosetting phenolic resin and modified thermoplastic phenolic resin as binders, modified potassium titanate, red iron oxide, magnesium oxide, and zirconium silicate as friction modifiers, and steel fiber, zinc-aluminum alloy fiber, and mineral fiber as reinforcing fibers. By regulating the proportions of the various components and achieving a synergistic effect, the friction block exhibits a stable friction coefficient, excellent thermal conductivity, and low wear. Therefore, the present invention effectively overcomes some practical problems in the prior art and has high utilization value and practical significance.

[0070] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A brake pad friction material, characterized in that: The friction material is composed of the following components in parts by weight: 3-8 parts of modified thermosetting phenolic resin, 5-9 parts of modified thermoplastic phenolic resin, 3-6 parts of aramid, 7-10 parts of modified potassium titanate, 2-5 parts of stannous sulfide, 2-5 parts of synthetic graphite, 6-15 parts of mineral fiber, 6-11 parts of red iron oxide, 7-10 parts of silicon micropowder, 2-5 parts of friction powder, 5-10 parts of kaolin, 5-8 parts of zinc-aluminum alloy fiber, 3-8 parts of steel fiber, 5-8 parts of magnesium oxide, and 10-15 parts of zirconium silicate.

2. The brake pad friction material according to claim 1, characterized in that: The modified thermosetting phenolic resin is cashew nut shell oil modified thermosetting phenolic resin.

3. The brake pad friction material according to claim 1, characterized in that: The modified thermoplastic phenolic resin is a silicon-modified thermoplastic phenolic resin, and the fluidity of the modified thermoplastic phenolic resin at 125° C. is 60-90 mm.

4. The brake pad friction material according to claim 1, characterized in that: The modified potassium titanate is graphite surface-modified potassium titanate.

5. The brake pad friction material according to claim 1, characterized in that: The synthetic graphite is thermally modified synthetic graphite, the degree of graphitization of the synthetic graphite is 85-100%, and the synthetic graphite is a single-layer flake structure.

6. The brake pad friction material according to claim 1, characterized in that: The mineral fiber is a thermally modified mineral fiber, and the thermal conductivity of the thermally modified mineral fiber is 0.4-0.8 W / (m·K).

7. A brake pad, characterized in that: The brake pad comprises a steel back and a friction block made of the friction material according to any one of claims 1 to 6, wherein the steel back is fixedly connected to the friction block.

8. A method for preparing a brake pad according to claim 7, characterized in that: The steps include: Weighing and uniformly mixing modified thermoplastic phenolic resin, aramid, modified potassium titanate, stannous sulfide, synthetic graphite, mineral fiber, red iron oxide, silicon powder, friction powder, kaolin, zinc-aluminum alloy fiber, steel fiber, magnesium oxide, and zirconium silicate according to a proportion to obtain a solid mixture; placing the solid mixture and the modified thermosetting phenolic resin in an internal mixer to obtain granular material; Placing the granular material and the steel back in a hot pressing mold cavity for hot pressing; The hot-pressed product is demoulded and heat-treated to obtain the brake pad.

9. The method for preparing a brake pad according to claim 8, characterized in that: During hot pressing, the pressing temperature is 135-155° C., the hot pressing pressure is 12-20 MPa, and the hot pressing time is 300-600 s.

10. The method for preparing a brake pad according to claim 8, characterized in that: During heat treatment, the product after demoulding by hot pressing is first baked at a temperature of 180 to 200° C. for 1 to 3 hours under a clamping force of 10 to 20 kN, and then baked at a temperature of 200 to 220° C. for 3 to 6 hours.

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