CN-121975177-A - Porous friction particle, preparation method thereof and friction material

Abstract

The invention relates to the technical field of friction materials, in particular to porous friction particles, a preparation method thereof and a friction material. The preparation method of the porous friction particles comprises the steps of S1, carrying out silane modification on PMMA microspheres, then grafting nano titanium dioxide on the surfaces to obtain surface modified pore-forming agents, S2, premixing citric acid and phenolic resin, then adding the surface modified pore-forming agents and polyacrylonitrile fibers, mixing and banburying, and then crushing to obtain a mixture, and S3, carrying out heating sintering on the mixture under the condition of gradient heating, crushing, ball milling and sieving to obtain the porous friction particles. The friction particles are porous carbon materials, the surfaces of the friction particles are provided with pores with gradient particle sizes, and the inner surfaces of the pores are adsorbed with rich nano-scale titanium dioxide, so that the friction particles have good heat dissipation and sound absorption functions, and the carbon skeleton of the friction particles also contains uniformly distributed carbon fibers, so that the friction particles have good mechanical properties.

Inventors

• TIAN JUN
• YANG BO
• HU GUOLIN
• GUO HONG

Assignees

• 成都超德创科技有限公司

Dates

Publication Date

20260505

Application Date

20260403

Claims (10)

1. 1. A method of preparing porous friction particles, comprising the steps of: S1, after PMMA microspheres are modified by silane, nano titanium dioxide is grafted on the surface of the PMMA microspheres to obtain a surface modified pore-forming agent; S2, premixing citric acid and phenolic resin, adding the surface modification pore-forming agent and polyacrylonitrile fiber, mixing, banburying and crushing to obtain a mixture; And S3, heating and sintering the mixture, crushing, ball milling and sieving to obtain the porous friction particles.
2. 2. The method of producing porous friction particles according to claim 1, wherein in step S1, the PMMA microspheres are provided with gradient particle diameters of 10 μm, 20 μm, 50 μm and 100. Mu.m.
3. 3. The method for preparing porous friction particles according to claim 1, wherein in the step S2, 5-20 parts by weight of the surface modification pore-forming agent, 30-50 parts by weight of the phenolic resin, 1-5 parts by weight of the citric acid and 5-15 parts by weight of the polyacrylonitrile fiber are calculated.
4. 4. The method of claim 1, wherein in step S2, the polyacrylonitrile fiber is subjected to a pre-oxidation treatment.
5. 5. The method for preparing porous friction particles according to claim 1, wherein in the step S2, the banburying temperature is 80-120 ℃, and the banburying time is 5-15 min.
6. 6. The preparation method of the porous friction particles according to claim 1, wherein in the step S3, the temperature rising sintering is gradient temperature rising, the gradient temperature rising speed is 5 ℃ per min, the temperature rising is carried out to 700-800 ℃, and then the sintering is carried out, and the temperature is kept for 2-5 hours.
7. 7. A porous friction particle characterized by being prepared by the preparation method of the porous friction particle according to any one of claims 1 to 6.
8. 8. A friction material comprising the porous friction particles according to claim 7, wherein the porous friction particles account for 10 to 40wt%.
9. 9. The method of preparing a friction material as claimed in claim 8, comprising the steps of: And S4, mixing and hot-pressing the porous friction particles, phenolic resin, nitrile rubber powder, superfine barium sulfate, calcined kaolin and nano silica fume powder to obtain a finished product.
10. 10. The method for preparing the friction material according to claim 9, wherein in the step S4, the phenolic resin is 15-20 parts, the nitrile rubber powder is 2-5 parts, the superfine barium sulfate is 10-20 parts, the calcined kaolin is 5-10 parts and the nano silica fume powder is 2-6 parts by weight.

Description

Porous friction particle, preparation method thereof and friction material Technical Field The invention relates to the technical field of friction materials, in particular to porous friction particles, a preparation method thereof and a friction material. Background Today, with the development of technology, the pursuit of friction materials is not limited to its basic functions, but the industry's demands for friction materials tend to be functionally diverse, rather than limited to basic friction properties. For example, there is an ongoing effort in the industry to find a friction material with low brake noise to reduce the sharp noise created between friction plates during emergency braking of a vehicle. The braking noise is noise caused by friction self-excitation vibration, the friction self-excitation vibration is generally considered as generated by instability of a system caused by interface friction, the noise is further transmitted in the air, and the inherent characteristics of the friction material determine the intensity, frequency domain characteristics and the like of the friction vibration and the noise. In the field of friction materials, at present, friction materials with cashew nut shell oil which have the effects of increasing toughness and reducing noise are dominant, and the application of the friction materials can be divided into two types, wherein one type is to generate polymer resin through polymerization reaction or modify other resins to be directly used as matrix resin of the friction materials, and the other type is to prepare friction particles which are added into the friction materials as functional regulator. The friction particles, also called friction particles and friction powder, are granular functional additive materials for improving the specific performance of the friction material, and the friction particles can improve the functional characteristics of the friction material through a simple process, so that the friction particles play a very key role in the modern friction material. The friction particles are various, and comprise organic friction particles such as cashew nut shell oil friction powder, rubber modified particles and the like, and also comprise inorganic friction particles such as graphite, alumina, quartz powder and the like, and the effects of the friction particles comprise improving heat resistance, increasing flexibility, stabilizing friction coefficient and the like. Currently, friction particles with noise reduction function, namely cashew shell oil friction powder mentioned above, have noise reduction principles of chemical toughening, porosity increase and high temperature interface protection according to Liu Bawei et al. However, the noise reduction effect is limited, and as a polymer, heat resistance is poor, thermal decomposition and carbonization occur at high temperature, and thus elasticity and heat resistance are lost, resulting in a decrease in friction performance and noise reduction. Based on this, there is a need for a friction particle that achieves high efficiency in sound absorption and noise reduction while having good compression resistance, wear resistance and heat resistance. Disclosure of Invention The invention aims to overcome the defects of the prior art and provide friction particles which at least achieve the aim of achieving high-efficiency sound absorption and simultaneously have good physical strength and heat resistance. The invention aims at realizing the following technical scheme: A method of preparing porous friction particles comprising the steps of: S1, carrying out silane modification on PMMA microspheres, and then grafting nano titanium dioxide on the surface to obtain a surface modified pore-forming agent; s2, premixing citric acid and phenolic resin, adding the surface modification pore-forming agent and polyacrylonitrile fiber, mixing and banburying, and then crushing to obtain a mixture; and S3, heating and sintering the mixture under the condition of gradient heating, crushing, ball milling and sieving to obtain the porous friction particles. In some embodiments, in step S1, the PMMA microspheres are provided with a plurality of gradient particle sizes, and the particle size range of the PMMA microspheres is 10-100 μm. In some examples, the gradient particle size includes 10 μm, 20 μm, 50 μm, and 100 μm. In some embodiments, in step S1, the silane coupling agent used for the silane modification is KH-550. In some embodiments, in the step S2, 5-20 parts by weight of the surface modified pore-forming agent, 30-50 parts by weight of phenolic resin, 1-5 parts by weight of citric acid and 5-15 parts by weight of polyacrylonitrile fiber are calculated. In some embodiments, in step S2, the polyacrylonitrile fiber is further pre-oxidized before mixing, where the pre-oxidizing temperature is 200-250 ℃ and the pre-oxidizing time is 0.5-1 h, so that the polyacrylonitrile fiber forms a heat-resistant trapezo