A biodegradable friction particle masterbatch, a friction material, and a preparation method and application thereof

Abstract

The present invention belongs to the technical field of friction materials, and discloses a biodegradable friction particle masterbatch, a friction material, and a preparation method and application thereof. The friction particle masterbatch contains polycaprolactone, polylactic acid, flaky calcium carbonate, calcium sulfate whiskers, and halloysite nanotubes. The friction material contains the friction particle masterbatch and a friction performance regulator. The present invention uses PLA, PBS, PBAT, and PCL as bonding components, modifies polycaprolactone with flaky calcium carbonate and calcium sulfate whiskers, and modifies polylactic acid with halloysite nanotubes, which can significantly improve the friction performance and wear resistance of the friction material. The prepared friction material not only has excellent comprehensive performance, but also is biodegradable, and has little environmental pollution during use and in the final degradation products.

Description

Technical Field

[0001] The present invention belongs to the technical field of friction materials, and particularly relates to a biodegradable friction particle masterbatch, a friction material, and a preparation method and application thereof. Background Art

[0002] Friction materials are a type of polymer ternary composite material, which is a physical and chemical complex. Generally, friction materials are composed of three major categories: polymer binders (resins and rubbers), reinforcing fibers, and friction property regulators, and are products made through a series of production processes.

[0003] At present, there are many friction materials on the market, including semi-metallic friction materials, NAO friction materials, powder metallurgy friction materials, and carbon fiber friction materials. Since friction materials contain phenolic resins, rubbers, metals, and various inorganic mineral materials, the toxic gases and friction dust generated during the friction process will cause air pollution, and the waste friction materials cannot be naturally degraded, which will cause long-term environmental pollution. Therefore, it is very necessary to provide an environmentally friendly friction material that does not generate toxic gases and polluting dust during use and can be degraded within a certain number of years.

[0004] Common biodegradable plastics include polylactic acid (PLA), polybutylene succinate (PBS), copolymers of butylene adipate and butylene terephthalate (PBAT), and polycaprolactone (PCL). Among them, PLA has good heat resistance but poor toughness; PBS and PBAT have good mechanical properties, good toughness, and high thermal stability, but low strength; PCL has large ductility but general heat resistance. Using them as raw materials for friction materials cannot meet the requirements of friction materials for friction performance and wear resistance.

[0005] Therefore, there is an urgent need to provide an environmentally friendly friction material that does not generate toxic gases and polluting dust during use, can be biodegradable, and has excellent friction performance. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. For this reason, the present invention provides a biodegradable friction particle masterbatch, a friction material, and a preparation method and application thereof. The friction material provided by the present invention has excellent comprehensive performance, good friction performance and wear resistance, and is biodegradable, with little environmental pollution during use and in the final degradation products.

[0007] The first aspect of the present invention provides a biodegradable friction particle masterbatch.

[0008] Specifically, a biodegradable friction particle masterbatch includes polycaprolactone (PCL), polylactic acid (PLA), flaky calcium carbonate, calcium sulfate whiskers, and halloysite nanotubes.

[0009] Preferably, by weight, the friction particle masterbatch comprises 0.5 - 5 parts of polycaprolactone (PCL), 3 - 15 parts of polylactic acid (PLA), 3 - 15 parts of flaky calcium carbonate, 20 - 30 parts of calcium sulfate whiskers, and 10 - 20 parts of halloysite nanotubes; More preferably, by weight, the friction particle masterbatch comprises 1 - 3 parts of polycaprolactone (PCL), 5 - 10 parts of polylactic acid (PLA), 5 - 10 parts of flaky calcium carbonate, 20 - 30 parts of calcium sulfate whiskers, and 10 - 20 parts of halloysite nanotubes.

[0010] Preferably, the friction particle masterbatch further comprises polybutylene succinate (PBS) and / or a copolymer of butylene adipate and butylene terephthalate (PBAT).

[0011] Preferably, the friction particle masterbatch further comprises at least one of tricalcium phosphate, montmorillonite, and diatomaceous earth. The hollow structure of diatomaceous earth can allow whiskers and organic substances in the material to insert, further enhancing the strength of the material; tricalcium phosphate and montmorillonite as fillers can improve the compatibility of each component, thereby further enhancing the heat resistance, toughness, and strength of the friction particle masterbatch.

[0012] Preferably, by weight, the friction particle masterbatch comprises 0.5 - 5 parts of polycaprolactone (PCL), 3 - 15 parts of polylactic acid (PLA), 3 - 15 parts of flaky calcium carbonate, 20 - 30 parts of calcium sulfate whiskers, 10 - 20 parts of halloysite nanotubes, 1 - 8 parts of polybutylene succinate (PBS), 1 - 8 parts of a copolymer of butylene adipate and butylene terephthalate (PBAT), 3 - 15 parts of tricalcium phosphate, 3 - 8 parts of montmorillonite, and 5 - 15 parts of diatomaceous earth.

[0013] More preferably, by weight, the friction particle masterbatch comprises 1 - 3 parts of polycaprolactone (PCL), 5 - 10 parts of polylactic acid (PLA), 5 - 10 parts of flaky calcium carbonate, 20 - 30 parts of calcium sulfate whiskers, 10 - 20 parts of halloysite nanotubes, 2 - 5 parts of polybutylene succinate (PBS), 2 - 5 parts of a copolymer of butylene adipate and butylene terephthalate (PBAT), 5 - 10 parts of tricalcium phosphate, 4 - 6 parts of montmorillonite, and 5 - 15 parts of diatomaceous earth.

[0014] The second aspect of the present invention provides a preparation method of a biodegradable friction particle masterbatch.

[0015] Specifically, a preparation method of a biodegradable friction particle masterbatch includes the following steps:

[0016] (1) Mix polycaprolactone (PCL) with flaky calcium carbonate and calcium sulfate whiskers, and knead to obtain material a;

[0017] (2) Mix poly(lactic acid) (PLA) with halloysite nanotubes and knead to obtain Material b;

[0018] (3) Mix the Material a obtained in step (1), the Material b obtained in step (2), and the remaining components, and knead to obtain the friction particle masterbatch.

[0019] In the present invention, polycaprolactone (PCL) is modified with flaky calcium carbonate and calcium sulfate whiskers, and poly(lactic acid) (PLA) is modified with halloysite nanotubes, and then kneaded to obtain the friction particle masterbatch. During the kneading of PCL, flaky calcium carbonate, and calcium sulfate whiskers, PCL fully coats the surface of the calcium sulfate whiskers and is covered in a layered manner by flaky calcium carbonate, making full use of the ductility of PCL and using flaky calcium carbonate for thermal oxidation isolation protection to improve its heat resistance; after kneading PLA and halloysite nanotubes, the halloysite nanotubes fill PLA, endowing PLA with sufficient toughness and further improving its heat resistance. The modified polycaprolactone (PCL) and poly(lactic acid) (PLA) act together to effectively improve the heat resistance, friction resistance, etc. of the friction particle masterbatch.

[0020] The third aspect of the present invention provides a biodegradable friction material.

[0021] Specifically, a biodegradable friction material includes the above-mentioned friction particle masterbatch and a friction performance regulator.

[0022] Preferably, the friction performance regulator includes graphite and / or coke. Graphite and coke can adjust the friction and wear characteristics and improve the friction resistance of the friction material.

[0023] Preferably, the friction material further includes gelatin for auxiliary bonding.

[0024] Preferably, by weight, the friction material contains 48 - 140 parts of the friction particle masterbatch, 5 - 20 parts of graphite, 5 - 20 parts of coke, and 1 - 8 parts of gelatin.

[0025] More preferably, by weight, the friction material contains 58 - 105 parts of the friction particle masterbatch, 5 - 15 parts of graphite, 5 - 15 parts of coke, and 2 - 5 parts of gelatin.

[0026] The fourth aspect of the present invention provides a preparation method of a biodegradable friction material.

[0027] Specifically, a preparation method of a biodegradable friction material includes the following steps:

[0028] Mix the friction particle masterbatch with graphite, coke, and gelatin, then put them into a mold and apply pressure to obtain a green body; then cure the green body to obtain the friction material.

[0029] Preferably, the pressurizing process is to pressurize to 400 - 600 Kg / cm 2 , and keep it for 3 - 5 minutes.

[0030] The fifth aspect of the present invention provides a brake pad.

[0031] Specifically, a brake pad contains the above-mentioned biodegradable friction material.

[0032] The bionic friction material provided by the present invention uses PLA, PBS, PBAT, and PCL as the main bonding components. First, modifiers such as tricalcium phosphate, plate-like calcium carbonate, calcium sulfate whiskers, montmorillonite, and halloysite nanotubes of bio-ceramic matrix materials are selected according to the characteristics of different polymer materials, and they are fully kneaded in a double-roll kneader at 80 - 110 °C for 30 - 50 minutes to form a composite polymer material with good comprehensive thermal and mechanical properties after blending modification, so that the polymer material and the bio-ceramic material are fully filled, and basic composite material structures with good wear resistance, damping, and strength are obtained respectively.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] (1) The friction material provided by the present invention uses PLA, PBS, PBAT, and PCL as bonding components, and uses plate-like calcium carbonate and calcium sulfate whiskers to modify polycaprolactone (PCL) respectively, and uses halloysite nanotubes to modify polylactic acid (PLA), which can significantly improve the friction performance and wear resistance of the friction material.

[0035] (2) The present invention uses biodegradable PLA, PBS, PBAT, and PCL as bonding components, uses bio-ceramics such as plate-like calcium carbonate, calcium sulfate whiskers, and halloysite nanotubes as modifying materials, cooperates with biodegradable materials of bio-ceramics such as tricalcium phosphate, montmorillonite, and diatomite, and the use of friction regulating materials such as natural graphite and petroleum coke. The prepared friction material not only has excellent comprehensive performance, but also is biodegradable, and has little environmental pollution during use and in the final degradation products. Specific Embodiments

[0036] In order to make those skilled in the art more clearly understand the technical solutions described in the present invention, the following examples are listed for illustration. It should be noted that the following examples do not limit the protection scope required by the present invention.

[0037] Unless otherwise specified, the raw materials, reagents, or devices used in the following examples can be obtained from conventional commercial channels, or can be obtained by existing known methods.

[0038] Example 1

[0039] A biodegradable friction particle masterbatch, by weight, consists of the following components:

[0040] 8 parts of PLA, 2 parts of PBS, 2 parts of PBAT, 3 parts of PCL, 5 parts of tricalcium phosphate, 8 parts of flaky calcium carbonate, 20 parts of calcium sulfate whiskers, 4 parts of montmorillonite, 13 parts of halloysite nanotubes and 10 parts of diatomite.

[0041] A preparation method of a biodegradable friction particle masterbatch, comprising the following steps:

[0042] (1) Put PCL, flaky calcium carbonate and calcium sulfate whiskers into a two-roll kneader, knead at 110 °C for 35 min, so that PCL fully coats the surface of the calcium sulfate whiskers and is covered by the flaky calcium carbonate in layers to obtain material a;

[0043] (2) Put PLA and halloysite nanotubes into a two-roll kneader, knead at 110 °C for 35 min, so that the halloysite nanotubes fill PLA to obtain material b;

[0044] (3) Mix the material a obtained in step (1), the material b obtained in step (2), as well as PBS, PBAT, tricalcium phosphate, montmorillonite and diatomite at a rotation speed of 300 rpm for 15 min, then knead in the kneader at 100 °C for 15 min, and then break after cooling to obtain the friction particle masterbatch.

[0045] A biodegradable friction material, by weight, consists of the following components: 75 parts of friction particle masterbatch, 15 parts of graphite, 15 parts of petroleum coke and 5 parts of gelatin.

[0046] A preparation method of a biodegradable friction material, comprising the following steps:

[0047] Weigh the friction particle masterbatch, graphite, petroleum coke and gelatin, add them to a high-speed mixer, mix at a rotation speed of 300 rpm for 3 min to obtain a friction material mixture; then put the friction material mixture into a hot mold, pressurize to 400 Kg / cm 2 , hold for 5 min to obtain a green body; finally, cure the green body at a curing temperature of 145 °C for 3 hours to obtain the friction material.

[0048] Example 2

[0049] A biodegradable friction particle masterbatch, by weight, consists of the following components:

[0050] 6 parts of PLA, 5 parts of PBS, 2 parts of PBAT, 3 parts of PCL, 10 parts of tricalcium phosphate, 10 parts of flaky calcium carbonate, 23 parts of calcium sulfate whiskers, 4 parts of montmorillonite, 10 parts of halloysite nanotubes and 5 parts of diatomite.

[0051] A preparation method of a biodegradable friction particle masterbatch, comprising the following steps:

[0052] (1) Put PCL, flaky calcium carbonate, and calcium sulfate whiskers into a two-roll kneader, knead at 105 °C for 45 min, so that the PCL fully coats the surface of the calcium sulfate whiskers and is covered by the flaky calcium carbonate in a layered manner to obtain material a;

[0053] (2) Put PLA and halloysite nanotubes into a two-roll kneader, knead at 110 °C for 45 min, so that the halloysite nanotubes fill the PLA to obtain material b;

[0054] (3) Mix the material a obtained in step (1), the material b obtained in step (2), PBS, PBAT, tricalcium phosphate, montmorillonite, and diatomite at a rotation speed of 300 rpm for 15 min, then knead in a kneader at 100 °C for 15 min, and then crush after cooling to obtain the friction particle masterbatch.

[0055] A biodegradable friction material, by weight, consists of the following components: 78 parts of friction particle masterbatch, 10 parts of graphite, 10 parts of petroleum coke, and 2 parts of gelatin.

[0056] A preparation method of a biodegradable friction material, comprising the following steps:

[0057] Weigh the friction particle masterbatch, graphite, petroleum coke, and gelatin, add them to a high-speed mixer, mix at a rotation speed of 300 rpm for 3 min to obtain a friction material mixture; then put the friction material mixture into a hot mold, pressurize to 600 Kg / cm 2 , keep for 3 min to obtain a green body; finally, cure the green body at a curing temperature of 145 °C for 3 hours to obtain the friction material.

[0058] Example 3

[0059] A biodegradable friction particle masterbatch, by weight, consists of the following components:

[0060] 6 parts of PLA, 3 parts of PBS, 3 parts of PBAT, 2 parts of PCL, 8 parts of tricalcium phosphate, 8 parts of flaky calcium carbonate, 30 parts of calcium sulfate whiskers, 4 parts of montmorillonite, 12 parts of halloysite nanotubes, and 5 parts of diatomite.

[0061] A preparation method of a biodegradable friction particle masterbatch, comprising the following steps:

[0062] (1) Put PCL, flaky calcium carbonate, and calcium sulfate whiskers into a two-roll kneader and knead at 100 °C for 40 min to fully coat the surface of the calcium sulfate whiskers with PCL and be covered layer by layer with flaky calcium carbonate to obtain material a;

[0063] (2) Put PLA and halloysite nanotubes into a two-roll kneader and knead at 90 °C for 40 min to fill the halloysite nanotubes into PLA to obtain material b;

[0064] (3) Mix the material a obtained in step (1), the material b obtained in step (2), as well as PBS, PBAT, tricalcium phosphate, montmorillonite, and diatomite at a rotation speed of 300 rpm for 15 min, then knead in the kneader at 100 °C for 15 min, and then crush after cooling to prepare the friction particle masterbatch.

[0065] A biodegradable friction material is composed of the following components by weight: 81 parts of friction particle masterbatch, 7 parts of graphite, 9 parts of petroleum coke, and 3 parts of gelatin.

[0066] A preparation method of a biodegradable friction material includes the following steps:

[0067] Weigh the friction particle masterbatch, graphite, petroleum coke, and gelatin, add them to a high-speed mixer, and mix at a rotation speed of 300 rpm for 3 min to obtain the friction material mixture; then put the friction material mixture into a hot mold, pressurize to 500 Kg / cm 2 , hold for 4 min to obtain a green body; finally, cure the green body at a curing temperature of 145 °C for 3 hours to prepare the friction material.

[0068] Example 4

[0069] A biodegradable friction particle masterbatch is composed of the following components by weight:

[0070] 10 parts of PLA, 4 parts of PBS, 2 parts of PBAT, 1 part of PCL, 6 parts of tricalcium phosphate, 6 parts of flaky calcium carbonate, 20 parts of calcium sulfate whiskers, 4 parts of montmorillonite, 14 parts of halloysite nanotubes, and 15 parts of diatomite.

[0071] A preparation method of a biodegradable friction particle masterbatch includes the following steps:

[0072] (1) Put PCL, flaky calcium carbonate, and calcium sulfate whiskers into a two-roll kneader and knead at 95 °C for 48 min to fully coat the surface of the calcium sulfate whiskers with PCL and be covered layer by layer with flaky calcium carbonate to obtain material a;

[0073] (2) Put PLA and halloysite nanotubes into a two-roll kneader and knead at 90 °C for 50 min to allow the halloysite nanotubes to fill PLA, obtaining Material b;

[0074] (3) Mix the Material a obtained in step (1), the Material b obtained in step (2), PBS, PBAT, tricalcium phosphate, montmorillonite, and diatomite at a rotation speed of 300 rpm for 15 min, then knead in a kneader at 100 °C for 15 min, and then crush after cooling to prepare a friction particle masterbatch.

[0075] A biodegradable friction material is composed of the following components by weight: 82 parts of friction particle masterbatch, 8 parts of graphite, 5 parts of petroleum coke, and 5 parts of gelatin.

[0076] A preparation method of a biodegradable friction material includes the following steps:

[0077] Weigh the friction particle masterbatch, graphite, petroleum coke, and gelatin, add them to a high-speed mixer, and mix at a rotation speed of 300 rpm for 3 min to obtain a friction material mixture; then put the friction material mixture into a hot mold, pressurize to 500 Kg / cm 2 , and keep it for 5 min to obtain a green body; finally, cure the green body at a curing temperature of 145 °C for 3 hours to prepare the friction material.

[0078] Example 5

[0079] A biodegradable friction particle masterbatch is composed of the following components by weight:

[0080] 12 parts of PLA, 6 parts of PBS, 6 parts of PBAT, 4 parts of PCL, 3 parts of tricalcium phosphate, 4 parts of flaky calcium carbonate, 18 parts of calcium sulfate whiskers, 8 parts of montmorillonite, 6 parts of halloysite nanotubes, and 4 parts of diatomite.

[0081] A preparation method of a biodegradable friction particle masterbatch includes the following steps:

[0082] (1) Put PCL, flaky calcium carbonate, and calcium sulfate whiskers into a two-roll kneader and knead at 100 °C for 40 min to allow PCL to fully coat the surface of the calcium sulfate whiskers and be covered by the flaky calcium carbonate in a layered manner, obtaining Material a;

[0083] (2) Put PLA and halloysite nanotubes into a two-roll kneader and knead at 90 °C for 40 min to allow the halloysite nanotubes to fill PLA, obtaining Material b;

[0084] (3) Mix the a material obtained in step (1), the b material obtained in step (2), PBS, PBAT, tricalcium phosphate, montmorillonite, and diatomaceous earth at a rotation speed of 300 rpm for 15 min, then knead at 100 °C in a kneader for 15 min, and then crush after cooling to obtain a friction particle masterbatch.

[0085] A biodegradable friction material is composed of the following components by weight: 71 parts of friction particle masterbatch, 5 parts of graphite, 18 parts of petroleum coke, and 6 parts of gelatin.

[0086] A preparation method of a biodegradable friction material includes the following steps:

[0087] Weigh the friction particle masterbatch, graphite, petroleum coke, and gelatin, add them to a high-speed mixer, and mix at a rotation speed of 300 rpm for 3 min to obtain a friction material mixture; then put the friction material mixture into a hot mold, pressurize to 500 Kg / cm 2 , and keep it for 4 min to obtain a green body; finally, cure the green body at a curing temperature of 145 °C for 3 hours to obtain the friction material.

[0088] Comparative Example 1

[0089] Comparative Example 1 provides a biodegradable friction material and its preparation method. The difference from Example 1 is that all components are directly mixed together to prepare the friction material.

[0090] Specifically, a biodegradable friction particle masterbatch is composed of the following components by weight:

[0091] 8 parts of PLA, 2 parts of PBS, 2 parts of PBAT, 3 parts of PCL, 5 parts of tricalcium phosphate, 8 parts of flaky calcium carbonate, 20 parts of calcium sulfate whiskers, 4 parts of montmorillonite, 13 parts of halloysite nanotubes, 10 parts of diatomaceous earth, 15 parts of graphite, 15 parts of petroleum coke, and 5 parts of gelatin.

[0092] A preparation method of a biodegradable friction material includes the following steps:

[0093] Weigh the above components, then add them together to a high-speed mixer, and mix at a rotation speed of 300 rpm for 3 min to obtain a friction material mixture; then put the friction material mixture into a hot mold, pressurize to 400 Kg / cm 2 , and keep it for 5 min to obtain a green body; finally, cure the green body at a curing temperature of 145 °C for 3 hours to obtain the friction material.

[0094] Comparative Example 2

[0095] The difference between Comparative Example 2 and Example 1 is that all the components used in the friction particle masterbatch in Example 1 are added into a two-roll kneader at one time, and after kneading, the friction particle masterbatch is prepared; then the friction particle masterbatch is mixed with gelatin, graphite, and coke, and cured to prepare the friction material.

[0096] Specifically, a biodegradable friction particle masterbatch is composed of the following components by weight:

[0097] 8 parts of PLA, 2 parts of PBS, 2 parts of PBAT, 3 parts of PCL, 5 parts of tricalcium phosphate, 8 parts of flaky calcium carbonate, 20 parts of calcium sulfate whiskers, 4 parts of montmorillonite, 13 parts of halloysite nanotubes, 10 parts of diatomite, 15 parts of graphite, 15 parts of petroleum coke, and 5 parts of gelatin.

[0098] A preparation method of a biodegradable friction material includes the following steps:

[0099] (1) Weigh PLA, PBS, PBAT, PCL, tricalcium phosphate, flaky calcium carbonate, calcium sulfate whiskers, montmorillonite, halloysite nanotubes, and diatomite, mix them at a rotation speed of 300 rpm for 15 min, then add them into a two-roll kneader, knead at 110 °C for 35 min, cool and crush after sufficient kneading to prepare the friction particle masterbatch;

[0100] (2) Add the friction particle masterbatch prepared in step (1), gelatin, graphite, and coke into a high-speed mixer, mix at a rotation speed of 300 rpm for 3 min to obtain the friction material mixture; then put the friction material mixture into a hot mold, pressurize to 400 Kg / cm 2 , keep it for 5 min to obtain the green body; finally, cure the green body at a curing temperature of 145 °C for 3 hours to prepare the friction material.

[0101] Comparative Example 3

[0102] Comparative Example 3 provides a biodegradable friction material and its preparation method. The difference from Example 3 is that flaky calcium carbonate and calcium sulfate whiskers are not used to modify PCL, and the remaining steps are the same as those in Example 3.

[0103] Specifically, a biodegradable friction material is composed of the following components by weight: 6 parts of PLA, 3 parts of PBS, 3 parts of PBAT, 2 parts of PCL, 8 parts of tricalcium phosphate, 8 parts of flaky calcium carbonate, 30 parts of calcium sulfate whiskers, 4 parts of montmorillonite, 12 parts of halloysite nanotubes, 5 parts of diatomite, 7 parts of graphite, 9 parts of petroleum coke, and 3 parts of gelatin.

[0104] A preparation method of a biodegradable friction material includes the following steps:

[0105] (1) Put PLA and halloysite nanotubes into a two-roll kneader and knead at 90 °C for 40 min to fill the halloysite nanotubes into PLA, obtaining Material b;

[0106] (2) Mix the Material b obtained in step (1) with PCL, flaky calcium carbonate, calcium sulfate whiskers, PBS, PBAT, tricalcium phosphate, montmorillonite, and diatomite at a rotational speed of 300 rpm for 15 min, then knead in the kneader at 100 °C for 15 min, and then crush after cooling to prepare the friction particle masterbatch.

[0107] (3) Put the friction particle masterbatch obtained in step (2), as well as graphite, petroleum coke, and gelatin, into a high-speed mixer and mix at a rotational speed of 300 rpm for 3 min to obtain the friction material mixture; then put the friction material mixture into a hot mold, pressurize to 500 Kg / cm 2 , and keep it for 4 min to obtain the green body; finally, cure the green body at a curing temperature of 145 °C for 3 hours to prepare the friction material.

[0108] Comparative Example 4

[0109] Comparative Example 4 provides a biodegradable friction material and its preparation method. The difference from Example 3 is that halloysite nanotubes are not used to modify PLA, and the remaining steps are the same as those in Example 3.

[0110] Specifically, a biodegradable friction material is composed of the following components by weight: 6 parts of PLA, 3 parts of PBS, 3 parts of PBAT, 2 parts of PCL, 8 parts of tricalcium phosphate, 8 parts of flaky calcium carbonate, 30 parts of calcium sulfate whiskers, 4 parts of montmorillonite, 12 parts of halloysite nanotubes, 5 parts of diatomite, 7 parts of graphite, 9 parts of petroleum coke, and 3 parts of gelatin.

[0111] A preparation method of a biodegradable friction material includes the following steps:

[0112] (1) Put PCL, flaky calcium carbonate, and calcium sulfate whiskers into a two-roll kneader and knead at 100 °C for 40 min to fully coat PCL on the surface of the calcium sulfate whiskers and be covered layer by layer with flaky calcium carbonate, obtaining Material a;

[0113] (2) Mix the Material a obtained in step (1) with halloysite nanotubes, PLA, PBS, PBAT, tricalcium phosphate, montmorillonite, and diatomite at a rotational speed of 300 rpm for 15 min, then knead in the kneader at 100 °C for 15 min, and then crush after cooling to prepare the friction particle masterbatch.

[0114] (3) Add the friction particle masterbatch obtained in step (2), as well as graphite, petroleum coke, and gelatin, into a high-speed mixer, and mix them at a rotation speed of 300 rpm for 3 min to obtain a friction material mixture; then put the friction material mixture into a hot mold, apply pressure to 500 Kg / cm 2 , and keep it for 4 min to obtain a green body; finally, cure the green body at a curing temperature of 145 °C for 3 hours to prepare the friction material.

[0115] Product effect test

[0116] Make the biodegradable friction materials prepared in Examples 1-5 and Comparative Examples 1-4 into brake pads, and then conduct performance tests. Test the friction performance according to the method in SAE2522, including the average friction coefficient, the first recession friction coefficient, the second recession friction coefficient, and the weight wear; test the shear strength according to the method of GB / T 22309-2008; conduct plant and animal toxicity tests according to GB / T41010-2021, evaluate the emergence rate index according to 4.5.1, and evaluate the earthworm survival rate index according to 4.5.2. The test results are shown in Table 1.

[0117] Table 1

[0118]

[0119] As can be seen from Table 1, the friction material provided by the embodiment of the present invention has stable friction coefficient, less wear, high shear strength, low toxicity to plants and animals, and little impact on the environment. When all components are directly kneaded or blended according to the methods of Comparative Examples 1 and 2, the shear strength of the material is relatively low, the wear value becomes larger, which will also significantly affect the friction coefficient and reduce the service life.

[0120] Compared with Example 3, in Comparative Example 3, PCL is not modified, and the thermal recession performance of the prepared friction material is significantly decreased, which is caused by the reduced heat resistance of PCL. Compared with Example 3, in Comparative Example 4, PLA is not modified, and the wear amount of the prepared friction material is significantly increased, and its strength is also inferior to that of Example 3. This is caused by the reduced toughness of PLA.

Claims

1. A friction particle masterbatch, characterized in that, By weight parts, the friction particle masterbatch comprises: 0.5 - 5 parts of polycaprolactone, 3 - 15 parts of polylactic acid, 3 - 15 parts of flaky calcium carbonate, 20 - 30 parts of calcium sulfate whiskers, 10 - 20 parts of halloysite nanotubes, 1 - 8 parts of polybutylene succinate, 1 - 8 parts of copolymer of butanediol adipate and butanediol terephthalate, 3 - 15 parts of tricalcium phosphate, 3 - 8 parts of montmorillonite, and 5 - 15 parts of diatomite; The friction particle masterbatch is prepared by a preparation method including the following steps: (1) Mix polycaprolactone with flaky calcium carbonate and calcium sulfate whiskers, and knead to obtain material a; (2) Mix polylactic acid with halloysite nanotubes, and knead to obtain material b; (3) Mix the material a obtained in step (1), the material b obtained in step (2), and the remaining components, and knead to obtain the friction particle masterbatch.

2. The preparation method of the friction particle masterbatch according to claim 1, characterized in that Including the following steps: (1) Mix polycaprolactone with flaky calcium carbonate and calcium sulfate whiskers, and knead to obtain material a; (2) Mix polylactic acid with halloysite nanotubes, and knead to obtain material b; (3) Mix the material a obtained in step (1), the material b obtained in step (2), and the remaining components, and knead to obtain the friction particle masterbatch.

3. A biodegradable friction material, characterized in that, Including the friction particle masterbatch as claimed in claim 1 and a friction performance regulator.

4. The friction material according to claim 3, wherein The friction performance regulator includes graphite and / or coke.

5. The friction material according to claim 4, characterized in that, The friction material further includes gelatin; by weight parts, the friction material comprises 48 - 140 parts of the friction particle masterbatch, 5 - 20 parts of graphite, 5 - 20 parts of coke, and 1 - 8 parts of gelatin.

6. The preparation method of the biodegradable friction material according to any one of claims 3-5, characterized in that, Including the following steps: Mix the friction particle masterbatch with graphite, coke, and gelatin, then put them into a mold, apply pressure to obtain a green body; then cure the green body to obtain the friction material.

7. A brake pad, characterized in that, Comprising the biodegradable friction material as claimed in any one of claims 3 - 5.

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