A high-damping base material, its preparation method and application

Abstract

The present invention discloses a high-damping base material, its preparation method and application, which relates to the technical field of braking materials. The preparation raw materials thereof include the following parts by mass: 10-40 parts of nitrile rubber, 4-10 parts of phenolic resin powder, 30-50 parts of composite reinforcing fibers, 0.5-5 parts of zinc powder, 10-40 parts of fillers, 0.6-2.3 parts of compatibilizer, and 0.2-4 parts of curing accelerator; the composite reinforcing fibers include para-aramid pulp, porous calcium silicate hydrate and metal fibers; wherein, the mass ratio of the para-aramid pulp: the porous calcium silicate hydrate: the metal fibers is 1:2-7:3-10; by mass fraction, the metal fibers are composed of 5-30% brass fibers, 3-20% aluminum fibers and the balance steel wool. The high-damping base material prepared by the present invention has the characteristics of high strength, high damping and low noise.

Description

Technical Field

[0001] The present invention belongs to the technical field of brake materials, and specifically relates to a high-damping base material, a preparation method thereof, and an application thereof. Background Art

[0002] Automobile friction plates are core components of the braking system. During braking, the stepping force is amplified through the brake pipeline to form hydraulic pressure, which pushes the friction plate into contact with the brake disc and generates friction, thereby achieving vehicle deceleration or stopping. This process belongs to dry friction. However, due to the material differences between the friction plate and the brake disc, the changes in the stepping force, the temperature differences, and the braking speed differences, brake tremors often occur, which in turn cause noise and abnormal sounds.

[0003] To solve the problem of brake noise, the industry has taken various measures: one is to develop friction plates with different material formulas, such as semi-metallic, low-metallic, and non-metallic friction plates, to reduce the noise between the friction plate and the cast iron brake disc by reducing the iron content in the metal; the second is to add damping and noise-reducing materials to the friction plate, such as nitrile rubber powder, vermiculite powder, and hollow glass beads; the third is to stick a damping rubber sheet on the steel back of the friction plate. Although these methods can reduce noise to a certain extent, they cannot completely eliminate it, and there are some risks. For example, adding too much nitrile rubber powder will cause thermal fade, too much vermiculite will increase wear, and a high proportion of hollow glass beads will make the friction coefficient too high, thus reducing the braking comfort. Summary of the Invention

[0004] In order to overcome the technical problems of brake noise and abnormal sounds, the present invention provides a high-damping base material, a preparation method thereof, and an application thereof. On the basis of not losing the friction and wear performance of the friction plate, the high-damping base material prepared by the present invention has the characteristics of high strength, high damping, and low noise.

[0005] The present invention solves the above technical problems through the following technical solutions.

[0006] The present invention provides a high-damping base material, which comprises the following raw materials for preparation in parts by mass: 10-40 parts of nitrile rubber, 4-10 parts of phenolic resin powder, 30-50 parts of composite reinforcing fiber, 0.5-5 parts of zinc powder, 10-40 parts of filler, 0.6-2.3 parts of compatibilizer, and 0.2-4 parts of curing accelerator;

[0007] Preferably, the high-damping base material comprises the following raw materials for preparation in parts by mass: 20-30 parts of nitrile rubber, 5-9 parts of phenolic resin powder, 35-46 parts of composite reinforcing fiber, 1-4 parts of zinc powder, 15-32 parts of filler, 0.6-1.8 parts of compatibilizer, and 0.2-3 parts of curing accelerator;

[0008] The brass fiber and steel wool are soaked with a silane coupling agent and then dried, and then aluminum fiber is added and mixed to obtain metal fiber;

[0009] The fiber length of the para-aramid pulp is 0.5 to 1.5 mm, preferably 0.7 to 1.4 mm;

[0010] The specific surface area of the para-aramid pulp is 5 to 13 m 2 / g;

[0011] The density of the para-aramid pulp is 1.42 to 1.46 g / cm 3 ;

[0012] By mass, the chemical composition of the steel wool includes C: 0.07 to 0.12%, Si ≤ 0.07%, Mn: 0.8 to 1.25%, S ≤ 0.03%, P ≤ 0.03%;

[0013] The tapped volume of the brass fiber is 0.5 to 0.8 mL / g;

[0014] The outer diameter of the aluminum fiber is 8 to 30 μm, preferably 20 to 30 μm;

[0015] The elongation of the aluminum fiber ≥ 2%.

[0016] The composite reinforcing fiber includes para-aramid pulp, porous calcium silicate hydrate and metal fiber; wherein, the mass ratio of the para-aramid pulp: the porous calcium silicate hydrate: the metal fiber is 1: 2 to 7: 3 to 10, preferably 1: 2 to 5: 4 to 7;

[0017] By mass fraction, the metal fiber is composed of 5 to 30% brass fiber, 3 to 20% aluminum fiber and the balance steel wool; preferably, the metal fiber is composed of 12 to 26% brass fiber, 7 to 16% aluminum fiber and the balance steel wool.

[0018] In the present invention, the phenolic resin powder is a thermosetting phenolic resin or a modified phenolic resin powder;

[0019] Among them, the modified phenolic resin powder is a rubber-modified phenolic resin powder, a silicon-modified phenolic resin powder, a cashew shell oil-modified phenolic resin powder; preferably a cashew shell oil-modified phenolic resin powder;

[0020] The cashew shell oil-modified phenolic resin powder can effectively absorb vibration and frictional energy and reduce the occurrence of noise by adjusting the porosity and thermal expansion coefficient of the friction material.

[0021] In the present invention, the particle size of the phenolic resin powder ≤ 75 μm.

[0022] In the present invention, the filler is at least one of barium sulfate, calcium carbonate, mica powder and zinc oxide.

[0023] In the present invention, the particle size of the filler ≤ 45 μm.

[0024] The composite reinforcing fibers form a rigid fiber network with an aspect ratio in the rubber matrix, which can improve the dissipation of external frictional vibration energy by the rubber matrix, reduce the vibration amplitude, and thus reduce the braking noise.

[0025] In the present invention, the compatibilizer is a maleic anhydride grafted compatibilizer or a silane coupling agent; preferably a maleic anhydride grafted compatibilizer; preferably, the maleic anhydride grafted compatibilizer is a maleic anhydride grafted ABS blend.

[0026] The maleic anhydride grafted compatibilizer can enhance the bonding force between nitrile rubber and inorganic fillers or fibers; at the same time, it can also react with phenolic resin powder to improve the interfacial adhesion between phenolic resin powder and composite reinforcing fibers; and improve the interfacial tension between the composite reinforcing fibers and the matrix, making the distribution of the composite reinforcing fibers in the matrix more uniform.

[0027] In the present invention, the curing accelerator is a hexamethylenetetramine curing accelerator.

[0028] In the present invention, the preparation raw materials of the high damping base material further include additives, and the additives are at least one of a dye, a flame retardant, and an antioxidant.

[0029] Furthermore, by mass, the additives include 0 - 7 parts of dye, 0 - 2 parts of flame retardant, and 0 - 3 parts of antioxidant.

[0030] In the present invention, the dye is carbon black, iron black, iron red, or chromium green.

[0031] In the present invention, the flame retardant is at least one of antimony trioxide, decabromodiphenylethane, aluminum dihydrogen tripolyphosphate, and zinc borate.

[0032] In the present invention, the antioxidant is an arylamine antioxidant; preferably, the antioxidant is a diarylamine antioxidant, a p-phenylenediamine antioxidant, or a p-phenylenediamine antioxidant.

[0033] The present invention provides a method for preparing the high damping base material as described above, comprising the following steps:

[0034] S1. After pre-treating brass fibers and steel wool, aluminum fibers are added and mixed to obtain metal fibers: the pre-treatment is to soak with a 5 - 10% mass fraction of silane coupling agent for 5 - 10 minutes and then dry.

[0035] S2. Plasticate nitrile rubber, and then subject the other preparation raw materials of the high damping base material to low-temperature internal mixing, calendering, and cooling to obtain a rubber block.

[0036] S3. Crush and screen the rubber block to obtain the high damping base material.

[0037] The silane coupling agent is KH550, KH560 or KH570.

[0038] The silane coupling agent can improve the corrosion resistance of metal fibers and also enhance the bonding force between metal fibers and other components.

[0039] In the present invention, both the low-temperature mixing and the plasticizing are carried out in a mixer. When performing low-temperature mixing and plasticizing, the temperature in the mixing chamber is ≤120°C;

[0040] The rotation speed of the mixer is 10 - 80 rpm, preferably 20 - 50 rpm;

[0041] The filling factor of the mixer is 0.8 - 2.5 times, preferably 1.0 - 1.5 times;

[0042] The pressing pressure of the mixer is 0.5 - 1.5 MPa, preferably 0.6 - 0.8 MPa.

[0043] In the present invention, the time for plasticizing is 5 - 20 min, preferably 5 - 10 min.

[0044] In the present invention, the time for low-temperature mixing is 5 - 30 min, preferably 10 - 20 min.

[0045] In the present invention, the roll speed for calendering is 25 - 60 rpm.

[0046] In the present invention, the roll temperature for calendering is 50 - 90°C.

[0047] In the present invention, the roll gap for calendering is 0.5 - 2 mm.

[0048] In the present invention, the cooling water temperature for cooling is 20 - 30°C.

[0049] In the present invention, the particle size of the sieve mesh for screening is ≤3 mm.

[0050] The present invention also provides the application of the high-damping base material obtained as described above or by the preparation method in friction plates. The friction plate sequentially includes a steel back, the high-damping base material, and a friction material facing from bottom to top.

[0051] In the present invention, the thickness of the steel back is 4 - 6 mm; the thickness of the high-damping base material is 2 - 2.5 mm; the thickness of the friction material facing is 8 - 15 mm.

[0052] In the present invention, the preparation of the friction plate includes the following steps: spreading the high-damping base material and the friction material facing flatly on the surface of the glue-coated steel back, and then performing hot pressing and curing to obtain the friction plate.

[0053] Furthermore, the hot pressing temperature is 130-160°C, the pressure is 30-50 MPa°C, and the time is 3-8 min.

[0054] Furthermore, the curing temperature is 200-230° C., and the curing time is 8-12 hours.

[0055] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] 1. The aramid pulp in the composite reinforcing fiber in the high damping base material of the present invention affects the friction coefficient and the wear rate. Adding too much will cause the friction coefficient to no longer change significantly, and may even reduce the surface adsorption area, increase wear, and reduce interface adhesion due to particle aggregation. Polyhydrated calcium silicate has a large specific surface area and a porous structure, which can adsorb and disperse other fillers, improve the uniformity and stability of the friction material, and enhance thermal stability. Metal fiber reinforces the hardness and toughness of the material, and improves wear resistance and thermal conductivity. It can form a non-continuous fiber network when dispersed in the rubber matrix, enhance the strength and stiffness of the matrix, absorb and dissipate vibration energy, thereby improving damping and reducing noise. By rationally matching aramid pulp, polyhydrated calcium silicate and metal fiber, the performance of the friction material can be optimized, and a balance between low noise, high stability and good wear resistance can be achieved.

[0058] 2. The steel fiber in the metal fiber provides high strength and wear resistance, the brass fiber provides corrosion resistance and thermal stability, and the aluminum fiber balances the friction coefficient and adaptability. The combination of the three makes the friction material more stable when subjected to impact, shear and centrifugal forces.

[0059] 3. The friction plate prepared by the high damping base material of the present invention has high shear strength and high damping characteristics. The shear strength at room temperature (23±5°C) is ≥6.4MPa, and in some preferred embodiments, it is 6.4~7.0MPa; the shear strength at high temperature (300±5°C) is ≥3.64MPa, and in some preferred embodiments, it is 6.4~4.0MPa. The probability of the friction pair assembled by the friction plate emitting a noise of >70Db is ≤2.3%, and in some preferred embodiments, it is 1.1~2.3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a microscopic image of the high damping base material prepared in Example 1.

[0061] Figure 2 It is a structural schematic diagram of high damping base material.

[0062] Figure 3 Schematic diagram of the structure of the friction plate prepared with high damping base material. Detailed implementation manners

[0063] To facilitate the understanding of the present invention, the present invention will be described more comprehensively and in detail below in conjunction with preferred embodiments. However, the protection scope of the present invention is not limited to the following specific embodiments.

[0064] Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0065] The nitrile rubber grade used in the following examples is LG (South Korea) Chem NBR 6250, and the nitrile rubber is a high acrylonitrile type nitrile rubber;

[0066] The cashew shell oil modified phenolic resin powder is purchased from Shandong Yonghui New Materials Co., Ltd., and the model is PF-221 or PF-222; the hexamine content of the cashew shell oil modified phenolic resin powder is 8-9%, and D95 is 250 mesh;

[0067] Antioxidants: The models are antioxidant DNP (diphenylamine antioxidant), antioxidant IPPD (p-phenylenediamine antioxidant) or antioxidant 6PPD (p-phenylenediamine antioxidant);

[0068] Para-aramid pulp is purchased from DuPont Kevlar 1F538 in the United States. The specific gravity of the para-aramid pulp is 1.45 g / cm 3 、The fiber length is 1.00 - 1.34 mm, and the fiber specific surface area is 5 - 11 m 2 / g;

[0069] Porous calcium silicate hydrate is purchased from Jiangxi Dishi Mineral Fiber Technology Co., Ltd.;

[0070] Steel wool is purchased from Dezhou Fangyuan Steel Wool Fiber Co., Ltd. D0-160. The chemical composition of the steel wool is C: 0.07 - 0.12%, Si ≤ 0.07%, Mn: 0.8 - 1.25%, S < 0.03%, P < 0.3%;

[0071] Brass fiber is purchased from Zhangjiagang Xinli Metal Co., Ltd. SB-1060. The brass fiber is crushed brass fiber, and the tapped volume is 0.5 - 0.8 mL / g;

[0072] Aluminum fiber is purchased from Jiangsu Wardesa Mold Technology Co., Ltd. The aluminum fiber is continuous micron-level metallic aluminum fiber, the aluminum fiber grade is 1060, the outer diameter of the aluminum fiber is 20 - 30 μm, and the elongation of the aluminum fiber ≥ 2%;

[0073] Compatibilizer: The maleic anhydride graft compatibilizer is purchased from Ketong Plastics KT-3, and this compatibilizer is a blend of maleic anhydride grafted ABS;

[0074] Curing accelerator: hexamine curing agent.

[0075] The microscopic images were measured by Keyence three-dimensional super-depth-of-field digital microscope VHX-X1.

[0076]

High-damping friction base material and its preparation method

[0077] Example 1

[0078] The formula of the high-damping base material in this example is as follows:

[0079] The high-damping base material is composed of the following raw materials in parts by mass: 22 parts of nitrile rubber, 5 parts of phenolic resin powder, 46 parts of composite reinforcing fiber, 1 part of zinc powder, 23 parts of filler, 3 parts of coloring agent (carbon black), 1.8 parts of compatibilizer, and 0.7 part of curing accelerator;

[0080] In this example, the phenolic resin powder is cashew shell oil modified phenolic resin powder;

[0081] In this example, the mass ratio of para-aramid pulp: porous hydrated calcium silicate: metal fiber in the composite reinforcing fiber is 1:2.5:4.2;

[0082] In this example, by mass fraction, the metal fiber is composed of 23% brass fiber, 15% aluminum fiber, and the balance steel wool;

[0083] In this example, the filler is 20 parts of barium sulfate and 3 parts of zinc chloride.

[0084] The preparation method of the high-damping friction base material in this example is as follows:

[0085] S1. Immerse the brass fiber and steel wool in an 8% mass fraction of silane coupling agent (KH560) for 6 min and then dry; after drying, add the aluminum fiber and mix to obtain the metal fiber;

[0086] S2. The rotation speed of the internal mixer is 30 rpm, the filling factor is 1.2 times, the pressing pressure is 0.6 MPa, and the temperature in the internal mixing chamber is controlled at 110 °C. If the temperature is too high, water can be added to adjust the temperature. The addition of water can make pores in the rubber compound, promoting the mutual penetration and combination of rubber and other raw materials such as fillers;

[0087] Add nitrile rubber to the internal mixer and plasticize for 10 min, then add other raw materials in the high-damping base material and carry out low-temperature internal mixing for 15 min;

[0088] Then carry out calendering on the open mill, the roll temperature is 60 °C, the roll speed is 35 rpm, the roll gap is 1.2 mm, and then cool. The cooling temperature is 25 °C and the cooling speed ratio is 1:1.17; after cooling, a rubber block is obtained.

[0089] After crushing and screening the rubber blocks, a high-damping base material is obtained, and the screening particle size is ≤ 3 mm.

[0090] The micrograph of the high-damping friction base material prepared in this example is shown in Figure 1 (The scale bar in the figure is 500 μm). The structural schematic diagram is shown in Figure 2 , Nitrile rubber serves as the matrix to provide flexibility and elasticity; Para-aramid pulp is dispersed in the nitrile rubber matrix to form a network support structure; Metal fibers are intertwined with organic fibers to form a "rigid-flexible combination" composite reinforcement system; Porous hydrated silicic acid combines with other components due to its porous and high specific surface area structure to form a heat-resistant barrier and inhibit the phenomenon of heat fade; Other powder materials such as phenolic resin powder, filler, zinc powder, etc. are evenly dispersed in the matrix, and the surface characteristics of the material are optimized through micro-filling, which can balance the friction coefficient, improve strength and damping performance.

[0091] Example 2

[0092] The difference between this example and Example 1 is:

[0093] By mass, the formulation of the high-damping base material in this example: 27 parts of nitrile rubber, 8 parts of phenolic resin powder, 38 parts of composite reinforcing fiber, 1.5 parts of zinc powder, 17 parts of filler, 1.5 parts of compatibilizer, 2.8 parts of curing accelerator;

[0094] The phenolic resin powder used in this example is thermosetting phenolic resin powder, purchased from Hangmo New Materials Co., Ltd. F2123-3.

[0095] All other steps and parameters are the same as those in Example 1.

[0096] Example 3

[0097] The difference between this example and Example 1 is:

[0098] By mass, the formulation of the high-damping base material in this example: 30 parts of nitrile rubber, 7 parts of phenolic resin powder, 35 parts of composite reinforcing fiber, 2.8 parts of zinc powder, 24 parts of filler, 1.8 parts of compatibilizer and 2.2 parts of curing accelerator;

[0099] In this example, the mass ratio of para-aramid pulp: calcium silicate hydrate: metal fiber in the composite reinforcing fiber is 1:3.5:5.4.

[0100] All other steps and parameters are the same as those in Example 1.

[0101] Example 4

[0102] The difference between this example and Example 1 is:

[0103] By mass parts, the formulation of the high-damping base material in this embodiment: 25 parts of nitrile rubber, 8 parts of phenolic resin powder, 42 parts of composite reinforcing fiber, 2.2 parts of zinc powder, 28 parts of filler, 3.7 parts of dye (carbon black), 1.1 parts of compatibilizer, and 2.3 parts of curing accelerator;

[0104] By mass fraction, the metal fiber in this embodiment is composed of 12% brass fiber, 16% aluminum fiber, and the balance steel wool.

[0105] All other steps and parameters are the same as those in Embodiment 1.

[0106] Embodiment 5

[0107] The formulation of the high-damping base material in this embodiment is as follows:

[0108] The high-damping base material is composed of the following raw materials in parts by mass: 22 parts of nitrile rubber, 5 parts of phenolic resin powder, 46 parts of composite reinforcing fiber, 1 part of zinc powder, 23 parts of filler, 3 parts of dye (carbon black), 1.8 parts of compatibilizer, 2.7 parts of antioxidant (antioxidant DNP), 1.5 parts of flame retardant (decabromodiphenylethane), and 0.8 part of curing accelerator;

[0109] In this embodiment, the filler is 20 parts of barium sulfate and 8 parts of calcium carbonate.

[0110] All other steps and parameters are the same as those in Embodiment 1.

[0111] Embodiment 6

[0112] The difference between this embodiment and Embodiment 1 lies in:

[0113] The metal fiber in this embodiment is not pretreated. S1: Directly mix brass fiber, aluminum fiber, and steel wool to obtain the metal fiber.

[0114] All other steps and parameters are the same as those in Embodiment 1.

[0115] Comparative Example 1

[0116] The difference between this comparative example and Embodiment 1 lies in:

[0117] The composite reinforcing fiber in this comparative example does not contain porous calcium silicate hydrate, and the mass ratio of aramid pulp to metal fiber in the composite reinforcing fiber is 1:4.2.

[0118] All other steps and parameters are the same as those in Embodiment 1.

[0119] Comparative Example 2

[0120] The difference between this comparative example and Embodiment 1 lies in:

[0121] The composite reinforcing fiber of this comparative example does not contain metal fiber, and the mass ratio of aramid pulp to porous hydrated calcium silicate in the composite reinforcing fiber is 1:2.5.

[0122] All other steps and parameters are the same as those in Example 1.

[0123] Comparative Example 3

[0124] The difference between this comparative example and Example 1 lies in:

[0125] The aramid pulp of the composite reinforcing fiber in this comparative example, and the mass ratio of porous hydrated calcium silicate to metal fiber in the composite reinforcing fiber is 2.5:4.2.

[0126] All other steps and parameters are the same as those in Example 1.

[0127] Comparative Example 4

[0128] The difference between this comparative example and Example 1 lies in:

[0129] The mass ratio of aramid pulp to porous hydrated calcium silicate to metal fiber in the composite reinforcing fiber of this comparative example is 5:2.5:4.2.

[0130] All other steps and parameters are the same as those in Example 1.

[0131] Comparative Example 5

[0132] The difference between this comparative example and Example 1 lies in:

[0133] By mass fraction, the metal fiber of this comparative example is composed of 33% brass fiber and the balance steel wool.

[0134] All other steps and parameters are the same as those in Example 1.

[0135] Comparative Example 6

[0136] The difference between this comparative example and Example 1 lies in:

[0137] By mass fraction, the metal fiber of this comparative example is composed of 3% brass fiber, 25% aluminum fiber and the balance steel wool.

[0138] All other steps and parameters are the same as those in Example 1.

[0139]

Friction Plate

[0140] The friction plate sequentially includes a steel back, a high-damping base material and a friction material facing from bottom to top. For the structural schematic diagram of the friction plate, see Figure 3 .

[0141] The high-damping base materials prepared in Examples 1 to 6 and Comparative Examples 1 to 6 were respectively processed into friction plates 1 to 6 and comparative friction plates 1 to 6; the preparation process of preparing the high-damping base material into a friction plate is as follows:

[0142] Friction material fabric is proportioned by mass parts. The raw materials for preparing the friction material fabric are as follows: 7 parts of solvent-free cashew resin (Kaled NX-4778), 3 parts of cashew shell oil friction powder (Kaled NX-2020-30), 2 parts of para-aramid pulp, 30 parts of potassium titanate fiber (KS-WTS-1 from Bengbu Guotai Nano Materials Co., Ltd.), 13 parts of barium sulfate, 20 parts of zirconia, and 15 parts of artificial graphite;

[0143] Pour the friction material fabric and the high-damping base material into the steel film cavity in sequence, and then place the glue-coated steel back on the surface of the high-damping base material layer. Start the hot press. The hot pressing temperature is 150 °C, the pressure is 40 MPa, and the hot pressing time is 4 min;

[0144] Then cure in an oven for 9 h, and the curing temperature is 230 °C;

[0145] The steel back thickness of the friction plate and the comparative friction plate is 6 mm, the thickness of the high-damping base material is 2 mm, and the thickness of the friction material fabric is 10 mm.

[0146] Comparative friction plate 7

[0147] The difference between this comparative friction plate and friction plate 1 is as follows:

[0148] The friction plate of this comparative example is composed of a steel back and a friction material fabric;

[0149] In the preparation process of this comparative friction plate, the high-damping base material is not used, and the obtained comparative friction plate 8 is composed of a 6-mm steel back and a 12-mm friction material fabric.

[0150]

Friction plate performance test

[0151] Test the shear strength of friction plates 1-6 and comparative friction plates 1-7. The test method refers to GB / T 22309-2023. It is required that the shear strength at room temperature (23 ± 5 °C) ≥ 2.5 MPa, and the shear strength at high temperature (300 ± 5 °C) ≥ 1.5 MPa; the test results are shown in Table 1.

[0152]

[0153] Detect the frequency-damping characteristics according to the SAE J2598-2020 standard. Detection equipment: Jurid-01 instrumen for natural frequency-damping characteristics. The DPR value (Damping rate) represents the energy dissipation ability of the material under dynamic load. The higher the DPR value, the more energy is dissipated by the material during deformation, and the better the damping performance. Materials with a high DPR value can more effectively absorb vibrations and impacts, and can also effectively reduce the noise in automotive friction braking.

[0154] Test principle:

[0155] (1)Use a shock hammer to trigger the brake pad and measure the response through a microphone or accelerometer; use an FFT analyzer to calculate the frequency response function (FRF) to obtain the resonance frequency and the corresponding amplitude.

[0156] (2)Find the resonance peak on the FRF curve and record the resonance frequency (i.e., the frequency corresponding to the peak of the resonance peak).

[0157] (3)On both sides of the resonance peak, find the frequency points where the amplitude drops by 3 dB; the frequency range between these two frequency points is called the half-power bandwidth, denoted as Δf.

[0158] (4)The damping ratio η (i.e., the DPR value) is calculated by the following formula: η = Δf / f.

[0159] (5)The above data can be directly read from the detector.

[0160] Where, Δf is the half-power bandwidth (Hz), and f is the resonance frequency (Hz).

[0161] The test result is the average value after four measurements, and the results are shown in Table 2.

[0162]

[0163]

Friction pair performance test

[0164] Combine the aforementioned friction plates 1 - 6 and the comparative friction plates 1 - 7 with a carbon-ceramic coated brake disc with a diameter of 380 mm to form carbon-ceramic friction pairs 1 - 6 and comparative friction pairs 1 - 7 respectively, and test the noise characteristics (incidence of noise > 70 Db) of the friction pairs on an inertial test bench of model Link3900 according to the standard SAEJ2521. The test results are shown in Table 3.

[0165]

[0166] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchases or can be prepared by existing methods. The above specific embodiments have further detailed the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A high-damping base material, characterized in that, The preparation raw materials include the following parts by mass: 10 to 40 parts of nitrile rubber, 4 to 10 parts of phenolic resin powder, 30 to 50 parts of composite reinforcing fiber, 0.5 to 5 parts of zinc powder, 10 to 40 parts of filler, 0.6 to 2.3 parts of compatibilizer, and 0.2 to 4 parts of curing accelerator; The composite reinforcing fiber includes para-aramid pulp, porous calcium silicate hydrate, and metal fiber; wherein, the mass ratio of the para-aramid pulp: the porous calcium silicate hydrate: the metal fiber is 1: 2 to 7: 3 to 10; By mass fraction, the metal fiber is composed of 5 to 30% brass fiber, 3 to 20% aluminum fiber, and the balance steel wool; The brass fiber and the steel wool are soaked with a silane coupling agent and then dried, and then the aluminum fiber is added and mixed to obtain the metal fiber; The fiber length of the para-aramid pulp is 0.5 to 1.5 mm; The specific surface area of the para-aramid pulp fibers is 5~13m 2 / g; By mass parts, the chemical composition of the steel wool includes C: 0.07 to 0.12%, Si≤0.07%, Mn: 0.8 to 1.25%, S≤0.03%, P≤0.03%; The tapped volume of the brass fiber is 0.5 to 0.8 mL / g; The outer diameter of the aluminum fiber is 8 to 30 μm; The elongation rate of the aluminum fiber is ≥2%; 2. The high-damping base material according to claim 1, characterized in that, Meet at least one of the following conditions ① to ④: ① The phenolic resin powder is a thermosetting phenolic resin or a modified phenolic resin powder; ② The particle size of the phenolic resin powder is ≤75 μm; ③ The filler is at least one of barium sulfate, calcium carbonate, mica powder, and zinc oxide; ④ The particle size of the filler is ≤45 μm.

3. The high-damping base material according to claim 2, wherein The modified phenolic resin powder is a rubber-modified phenolic resin powder, a silicon-modified phenolic resin powder, or a cashew shell oil-modified phenolic resin powder.

4. The high-damping base material according to claim 1, characterized in that, Meet at least one of the following conditions ① to ③: ① The compatibilizer is a maleic anhydride graft compatibilizer or a silane coupling agent; ② The curing accelerator is a hexamine curing agent; ③ The preparation raw materials of the high-damping base material may further include additives, and the additives are at least one of a dyeing agent, a flame retardant, and an antioxidant.

5. The preparation method of the high-damping base material according to any one of claims 1 to 4, characterized in that, It includes the following steps: S1. After the brass fiber and the steel wool are pretreated, the aluminum fiber is added and mixed to obtain the metal fiber: The pretreatment is to soak with a 5 to 10% mass fraction of silane coupling agent for 5 to 10 minutes and then dry; S2. The nitrile rubber is plastisized, and then the other preparation raw materials of the high-damping base material are subjected to low-temperature mixing, calendering, and cooling to obtain a rubber block; S3. The rubber block is crushed and screened to obtain the high-damping base material.

6. The preparation method of the high damping base material according to claim 5, characterized in that, Meet at least one of the following conditions ① to ③: ① Both the low-temperature mixing and the plastisizing are carried out in a mixer, and the temperature in the mixing chamber during low-temperature mixing and plastisizing is ≤120°C; ② The time of plastisizing is 5 to 20 minutes; ③ The time of low-temperature mixing is 5 to 30 minutes.

7. The preparation method of the high-damping base material according to claim 6, characterized in that, The rotation speed of the mixer is 10 to 80 rpm, and the pressing pressure of the mixer is 0.5 to 1.5 MPa.

8. The preparation method of the high-damping base material according to claim 5, characterized in that, Meet at least one of the following conditions ① to ⑤: ① The roller speed of the calendering is 25 to 60 rpm; ② The roller temperature of the calendering is 50 to 90°C; ③ The roller gap of the calendering is 0.5 to 2 mm; ④ The cooling water temperature used for cooling is 20~30°C; ⑤ The particle size of the screening is ≤3 mm.

9. Application of the high-damping base material according to any one of claims 1 to 4 or the high-damping base material prepared by the preparation method according to any one of claims 5 to 8 in a friction plate, characterized in that, The friction plate sequentially includes a steel backing, the high-damping base material, and a friction material fabric from bottom to top; The thickness of the steel backing is 4~6 mm; the thickness of the high-damping base material is 2~2.5 mm; the thickness of the friction material fabric is 8~15 mm.

10. The application of the high-damping base material in the friction plate according to claim 9, characterized in that, The preparation of the friction plate includes the following steps: spreading the high-damping base material and the friction material fabric flat on the surface of the glue-coated steel backing, and then performing hot pressing and curing to obtain the friction plate.

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