Preparation method of copper-free composite resin brake pad

Abstract

The present invention relates to the technical field of brake pads, and in particular to a method for preparing a copper-free composite resin brake pad. Components such as hollow microspheres, potassium titanate whiskers, fibers, phenolic resins, and fillers of the present invention are mixed and cross-overlapped to form a three-dimensional network structure. Tetrachlorobis(cyclohexylmercapto)titanium and (di-n-butyl)(vinyl) borate undergo a mercapto-olefin addition reaction, including coordination between the titanium center and the mercapto group and subsequent nucleophilic addition of the carbon-carbon double bond. The tetrachlorobis(cyclohexylmercapto)titanium complex promotes the nucleophilic attack of the mercapto group on the carbon-carbon double bond through the interaction between its metal center and the mercapto group, forming a stable thioether bond connection. A metal complex synergist containing methoxysilane, borate, urea, and diepoxytitanium functional groups improves the interfacial bonding force between the inorganic filler and the polymer matrix, enhances the mechanical properties and durability of the material, and is suitable for a variety of resin systems. The brake pad has a reinforcing effect and improves its shear strength.

Description

Technical Field

[0001] The invention relates to the technical field of brake pads, in particular to a method for preparing a copper-free composite resin brake pad. Background Art

[0002] Asbestos-free organic brake pads are a typical multi-component composite material, primarily composed of a resin binder, fiber reinforcement, fillers, and friction modifiers. The environmental and human hazards of copper-containing components and other heavy metal ingredients in brake pad formulations are a growing concern. Consequently, reducing the copper and heavy metal content in brake pad formulations and developing copper-free and low-metal brake pads has become a trend in the international automotive industry.

[0003] Chinese patent CN110905955B relates to a melamine-formaldehyde-based brake pad and its preparation method. This patent addresses the existing issues with phenolic resins used as binders in brake pads, which can release free phenols and harmful amine gases, as well as exhibit low friction coefficients and Shore hardness. This invention addresses these issues by using melamine-formaldehyde-based resin as a binder in brake pads, enabling the production of automotive brake pads.

[0004] Chinese patent CN107387617A: belongs to the field of brake pad technology, specifically discloses a high-temperature resistant and low-wear metal-free brake pad, which is made of the following components by weight: 7-23 parts of phenolic resin, 10-30 parts of friction powder, 7-23 parts of graphite, 3-9 parts of coke powder, 2-6 parts of nitrile powder, 5-15 parts of barite powder, 2-7 parts of montmorillonite nanopowder, 0.3-0.9 parts of 2,4,6-tris(dimethylaminomethyl)phenol, 7-23 parts of glass fiber, 2-8 parts of wood fiber, 10-17 parts of silicon carbide fiber, 5-15 parts of tire powder, 4-10 parts of nano-fluorite powder, 2-7 parts of nano-sepiolite powder, 3-9 parts of nano-silica aerogel powder, 2-6 parts of heavy calcium carbonate, and 5-15 parts of silane coupling agent.

[0005] Chinese patent CN107542816A: belongs to the field of brake pad technology, specifically discloses a low-noise and wear-resistant metal-free brake pad, which is made of the following components by weight: 7-23 parts of phenolic resin, 10-30 parts of friction powder, 7-23 parts of graphite, 3-9 parts of coke powder, 2-6 parts of nitrile powder, 5-15 parts of barite powder, 2-7 parts of montmorillonite nanopowder, 0.3-0.9 parts of 2,4,6-tris(dimethylaminomethyl)phenol, 7-23 parts of glass fiber, 2-8 parts of wood fiber, 10-17 parts of silicon carbide fiber, 5-15 parts of tire powder, 5-13 parts of modified kapok fiber, 3-9 parts of nano-silica aerogel powder, 2-6 parts of heavy calcium carbonate, and 5-15 parts of silane coupling agent.

[0006] However, the brake pads prepared by the above patents and similar prior arts have the following disadvantages: low shear strength, poor mechanical properties; low friction coefficient, and high wear rate. Summary of the Invention

[0007] (1) Technical issues to be solved

[0008] In order to solve the above problems in the prior art, the present invention provides a method for preparing a copper-free composite resin brake pad, which enhances the mechanical properties and durability of the brake pad material, has a reinforcing effect on the brake pad, and improves its shear strength.

[0009] (2) Technical solution

[0010] In order to achieve the above objectives, the main technical solutions adopted by the present invention include:

[0011] S1: Weigh 20-30 parts of barite, 10-20 parts of hollow microspheres, 10-20 parts of flake graphite, 1-5 parts of potassium titanate whiskers, and 10-20 parts of fiber in parts by weight, and pre-mix them in a high-speed mixer for 10-20 minutes; then add 5-10 parts of phenolic resin, 20-30 parts of filler, and 0.5-2.5 parts of metal complex synergist, and continue mixing and stirring for 10-20 minutes to obtain a mixture;

[0012] S2: sending the mixed material to a hot press for hot pressing;

[0013] S3: After hot pressing and forming, the product is placed in a drying oven for heat treatment to obtain a copper-free composite resin brake pad.

[0014] Furthermore, the fiber is one or more of aramid, glass fiber, wood fiber, silicon carbide fiber, and aluminum silicate fiber.

[0015] Furthermore, the filler is one of vermiculite, rubber powder and talc powder.

[0016] Furthermore, the temperature of the hot press is 150-170° C., the pressure is 10-20 MPa, and the time is 10-20 min.

[0017] Furthermore, the heat treatment temperature is 140-180° C. and the time is 1-3 hours.

[0018] Furthermore, the preparation mechanism of the metal complex synergist is:

[0019] 3-Mercaptopropyltrimethoxysilane reacts with (di-n-butyl)(vinyl)borate and allylphenyl urea to undergo a mercapto-olefin addition reaction; tetrachlorobis(cyclohexylmercapto)titanium reacts with (di-n-butyl)(vinyl)borate to undergo a mercapto-olefin addition reaction; the resulting metal complex synergist containing methoxysilane, borate, urea, and diepoxytitanium functional groups is used in the preparation of copper-free composite resin brake pads and facilitates the uniform mixing of phenolic resin and inorganic fillers such as potassium titanate whiskers.

[0020] Furthermore, the preparation method of the metal complex synergist is:

[0021] 20-40 parts by weight of 3-mercaptopropyltrimethoxysilane are weighed and added to a reactor, followed by the sequential addition of 500-600 parts of ethyl n-butyrate, 0.04-0.5 parts of tetrachlorobis(cyclohexylmercapto)titanium, 0.04-0.5 parts of allylphenyl urea, 30-50 parts of (di-n-butyl)(vinyl)borate, and 2-5 parts of potassium tert-butoxide. The mixture is heated to 60-70° C., stirred and reacted for 100-160 minutes, cooled, concentrated, and evaporated to remove the ethyl n-butyrate, thereby obtaining a metal complex synergist.

[0022] (3) Beneficial effects

[0023] The present invention provides a method for preparing a copper-free composite resin brake pad. Compared with the prior art, the present invention has the following significant effects:

[0024] 1. The hollow microspheres, potassium titanate whiskers, fibers, phenolic resins, fillers and other components of the present invention are mixed and cross-overlapped to form a three-dimensional network structure. Tetrachlorobis(cyclohexylmercapto)titanium and (di-n-butyl)(vinyl) borate undergo a mercapto-olefin addition reaction, including coordination between the titanium center and the mercapto group and subsequent nucleophilic addition of the carbon-carbon double bond. The tetrachlorobis(cyclohexylmercapto)titanium complex promotes the nucleophilic attack of the mercapto group on the carbon-carbon double bond through the interaction between its metal center and the mercapto group, forming a stable sulfide bond connection; the metal complex synergist containing methoxysilane, borate, urea, and diepoxy titanium functional groups improves the interfacial bonding between the inorganic filler and the polymer matrix, enhances the mechanical properties and durability of the material, and its applicability to various resin systems; it has a reinforcing effect on the brake pad and improves its shear strength;

[0025] 2. The hollow microspheres, flake graphite, and potassium titanate whiskers of the present invention can increase the friction coefficient, reduce the wear rate, and improve the wear resistance of the brake pad;

[0026] 3. The copper-free composite resin brake pad prepared by the present invention has excellent mechanical properties and friction and wear properties. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0028] Among them, the determination of shear strength, friction coefficient and wear rate shall be carried out in accordance with GB5763-2008.

[0029] Example 1

[0030] A method for preparing a copper-free composite resin brake pad, the operating steps of which are as follows:

[0031] S1: Weigh 20g of barite, 10g of hollow microspheres, 10g of flake graphite, 1g of potassium titanate whiskers, and 10g of fiber, place them in a high-speed mixer and premix them for 10 minutes; then add 5g of phenolic resin, 20g of filler, and 0.5g of metal complex synergist, and continue mixing and stirring for 10 minutes to obtain a mixture;

[0032] S2: sending the mixed material to a hot press for hot pressing;

[0033] S3: After hot pressing and forming, the product is placed in a drying oven for heat treatment to obtain a copper-free composite resin brake pad.

[0034] The fiber is aramid.

[0035] The filler is vermiculite.

[0036] The temperature of the hot press is 150° C., the pressure is 10 MPa, and the time is 10 minutes.

[0037] The heat treatment temperature is 140° C. and the time is 1 hour.

[0038] The preparation method of the metal complex synergist is:

[0039] Weigh 20 g of 3-mercaptopropyltrimethoxysilane and add it to the reactor, then add 500 g of ethyl butyrate, 0.04 g of tetrachlorobis(cyclohexylmercapto)titanium, 0.04 g of allylphenyl urea, 30 g of (di-n-butyl)(vinyl)borate, and 2 g of potassium tert-butoxide in sequence. Heat the mixture to 60 ° C and stir to react for 100 minutes, then cool, concentrate and evaporate the ethyl butyrate to obtain a metal complex synergist.

[0040] Example 2

[0041] A method for preparing a copper-free composite resin brake pad, the operating steps of which are as follows:

[0042] S1: Weigh 24 g of barite, 14 g of hollow microspheres, 14 g of flake graphite, 2 g of potassium titanate whiskers, and 14 g of fiber, place them in a high-speed mixer and premix for 15 min; then add 6 g of phenolic resin, 24 g of filler, and 1 g of metal complex synergist, and continue mixing and stirring for 15 min to obtain a mixture;

[0043] S2: sending the mixed material to a hot press for hot pressing;

[0044] S3: After hot pressing and forming, the product is placed in a drying oven for heat treatment to obtain a copper-free composite resin brake pad.

[0045] The fiber is glass fiber.

[0046] The filler is rubber powder.

[0047] The temperature of the hot press is 155° C., the pressure is 13 MPa, and the time is 15 minutes.

[0048] The heat treatment temperature is 150° C. and the time is 2 hours.

[0049] The preparation method of the metal complex synergist is:

[0050] Weigh 25 g of 3-mercaptopropyltrimethoxysilane and add it to the reactor, then add 530 g of ethyl butyrate, 0.2 g of tetrachlorobis(cyclohexylmercapto)titanium, 0.2 g of allylphenyl urea, 35 g of (di-n-butyl)(vinyl)borate, and 3 g of potassium tert-butoxide in sequence. Heat the mixture to 65 ° C and stir to react for 120 minutes, then cool, concentrate and evaporate the ethyl butyrate to obtain a metal complex synergist.

[0051] Example 3

[0052] A method for preparing a copper-free composite resin brake pad, the operating steps of which are as follows:

[0053] S1: Weigh 28g of barite, 18g of hollow microspheres, 18g of flake graphite, 4g of potassium titanate whiskers, and 18g of fiber, place them in a high-speed mixer and premix for 15 minutes; then add 9g of phenolic resin, 28g of filler, and 2g of metal complex synergist, and continue mixing and stirring for 15 minutes to obtain a mixture;

[0054] S2: sending the mixed material to a hot press for hot pressing;

[0055] S3: After hot pressing and forming, the product is placed in a drying oven for heat treatment to obtain a copper-free composite resin brake pad.

[0056] The fiber is wood fiber.

[0057] The filler is rubber powder.

[0058] The temperature of the hot press is 165° C., the pressure is 18 MPa, and the time is 15 minutes.

[0059] The heat treatment temperature is 170° C. and the time is 2 hours.

[0060] The preparation method of the metal complex synergist is:

[0061] 35 g of 3-mercaptopropyltrimethoxysilane was weighed and added to the reactor, followed by the addition of 580 g of ethyl n-butyrate, 0.4 g of tetrachlorobis(cyclohexylmercapto)titanium, 0.4 g of allylphenyl urea, 45 g of (di-n-butyl)(vinyl)borate, and 4 g of potassium tert-butoxide. The mixture was heated to 65 ° C and stirred for 140 minutes, then cooled, concentrated and evaporated to remove ethyl n-butyrate to obtain a metal complex synergist.

[0062] Example 4

[0063] A method for preparing a copper-free composite resin brake pad, the operating steps of which are as follows:

[0064] S1: Weigh 30g of barite, 20g of hollow microspheres, 20g of flake graphite, 5g of potassium titanate whiskers, and 20g of fiber, place them in a high-speed mixer and premix for 20min; then add 10g of phenolic resin, 30g of filler, and 2.5g of metal complex synergist, and continue mixing and stirring for 20min to obtain a mixture;

[0065] S2: sending the mixed material to a hot press for hot pressing;

[0066] S3: After hot pressing and forming, the product is placed in a drying oven for heat treatment to obtain a copper-free composite resin brake pad.

[0067] The fiber is silicon carbide fiber.

[0068] The filler is a kind of talcum powder.

[0069] The temperature of the hot press is 170° C., the pressure is 20 MPa, and the time is 20 minutes.

[0070] The heat treatment temperature is 180° C. and the time is 3 hours.

[0071] The preparation method of the metal complex synergist is:

[0072] 40 g of 3-mercaptopropyltrimethoxysilane was weighed and added to the reactor, followed by the addition of 600 g of ethyl n-butyrate, 0.5 g of tetrachlorobis(cyclohexylmercapto)titanium, 0.5 g of allylphenyl urea, 50 g of (di-n-butyl)(vinyl)borate, and 5 g of potassium tert-butoxide. The mixture was heated to 70 ° C and stirred for 160 minutes, then cooled, concentrated and evaporated to remove ethyl n-butyrate to obtain a metal complex synergist.

[0073] Comparative Example 1

[0074] This example is the same as Example 1 except that no metal complex synergist is added.

[0075] Comparative Example 2

[0076] This example is the same as Example 1 except that tetrachlorobis(cyclohexylmercapto)titanium is not added.

[0077] Comparative Example 3

[0078] This example is the same as Example 1 except that (di-n-butyl)(vinyl) borate is not added.

[0079] Test results

[0080]

[0081]

[0082] Through the data analysis of the above examples and comparative examples, the copper-free composite resin brake pad prepared by the present invention has high shear strength, high friction coefficient, low wear rate, and excellent mechanical properties and friction and wear properties.

[0083] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a copper-free composite resin brake pad, comprising the following steps: S1: Weigh 20-30 parts of barite, 10-20 parts of hollow microspheres, 10-20 parts of flake graphite, 1-5 parts of potassium titanate whiskers, and 10-20 parts of fiber in parts by weight, and pre-mix them in a high-speed mixer for 10-20 minutes; then add 5-10 parts of phenolic resin, 20-30 parts of filler, and 0.5-2.5 parts of metal complex synergist, and continue mixing and stirring for 10-20 minutes to obtain a mixture; S2: sending the mixed material to a hot press for hot pressing; S3: After hot pressing and forming, the brake pad is placed in a drying oven for heat treatment to obtain a copper-free composite resin brake pad; The preparation method of the metal complex synergist is: 20-40 parts by weight of 3-mercaptopropyltrimethoxysilane are weighed and added to a reactor, followed by the sequential addition of 500-600 parts of ethyl n-butyrate, 0.04-0.5 parts of tetrachlorobis(cyclohexylmercapto)titanium, 0.04-0.5 parts of allylphenyl urea, 30-50 parts of (di-n-butyl)(vinyl)borate, and 2-5 parts of potassium tert-butoxide. The mixture is heated to 60-70° C., stirred and reacted for 100-160 minutes, cooled, concentrated, and evaporated to remove the ethyl n-butyrate, thereby obtaining a metal complex synergist.

2. The method for preparing a copper-free composite resin brake pad according to claim 1, characterized in that: The fiber is one or more of aramid, glass fiber, wood fiber, silicon carbide fiber, and aluminum silicate fiber.

3. The method for preparing a copper-free composite resin brake pad according to claim 1, wherein: The filler is one of vermiculite, rubber powder and talcum powder.

4. The method for preparing a copper-free composite resin brake pad according to claim 1, wherein: The temperature of the hot press is 150-170° C., the pressure is 10-20 MPa, and the time is 10-20 minutes.

5. The method for preparing a copper-free composite resin brake pad according to claim 1, characterized in that: The heat treatment temperature is 140-180° C. and the time is 1-3 hours.

Images