CN104531070A - Softwood particle blending and modified rubber based friction material as well as preparation method and using method thereof - Google Patents

Abstract

The invention relates to a cork particle blended modified rubber-based friction material with high friction coefficient and low wear rate and a preparation process thereof. Its ingredients are 20-35wt% of silane coupling agent modified cork particles, 10-35wt% of rubber, 4-8wt% of organic resin binder, 6-10wt% of inorganic and organic reinforcing fibers, 9-9% of friction performance modifier and filler 25wt%, rubber additives 2-7wt%; the friction material uses silane coupling agent to modify the cork particles and other components in a comprehensive ratio, so that the dynamic friction coefficient of the material reaches 0.18-0.26, and the static friction coefficient reaches 0.27-0.35. The wear rate of the material is kept below 4×10 ^-8 cm ³ /J.

Description

Cork particle blending modified rubber-based friction material, preparation method and application method

technical field

The invention belongs to a rubber-based friction material and a preparation method and a use method thereof, in particular to a cork particle blended modified rubber-based friction material and a preparation method thereof, which can be used for motorcycle clutches.

Background technique

Friction material is a component material that is applied to power machinery and relies on friction performance to perform braking and transmission functions. It mainly includes brake linings and clutch surfaces. Friction materials are widely used in friction braking and transmission devices such as brakes and clutches of vehicles such as motorcycles and mechanical equipment.

According to the national standard GB/T13826-2008 of the People's Republic of China, the coefficient of dynamic friction of rubber-based friction materials for motorcycle clutches should be greater than 0.15, and the coefficient of static friction should not be less than 0.24. The traditional rubber-based friction material is composed of three major components: reinforcing fiber, rubber and resin binder, and friction modifier. There are two problems, such as high friction material wear, easy slipping, and rushing during clutch shifting; at the same time, because the pressure plate and center sleeve parts of the motorcycle clutch are made of aluminum alloy, the aluminum alloy is harder than steel during the transmission and braking process. Low, so the pair wears seriously during the working process, thus affecting the service life of the motorcycle clutch.

The Chinese patent with the publication number CN103205239A discloses a rubber-based friction material and its preparation method. Its formula contains 15% to 35% by mass of acrylic rubber; Mineral fiber or a mixture of more than one of them; 5% to 25% of multifunctional friction particles; 5% to 20% of alumina, or barite powder, or iron black, or chromite powder, or flake graphite, or Calcined petroleum coke or a mixture of one or more of them; 2% to 15% cashew nut shell oil friction powder; 2% to 15% cork particles; 2% to 15% cashew nut shell oil modified phenolic resin; 1% to 7% sulfur , or accelerator DM, or accelerator TMTD, or zinc oxide, or stearic acid, or a mixture of more than one of them. In this patent, the raw materials are mixed evenly by a high-speed mixer, and then the mixed materials are put into the internal mixer for internal mixing at 95°C to 105°C, and the rubber is mixed in the open mixer, and then the prefabricated body is put into a flat vulcanizing machine for heating. Press curing, and finally heat post-treatment to obtain rubber-based friction material. In this method, when the mixture is put into the internal mixer, the rubber component is vulcanized and cross-linked in advance due to the high temperature, resulting in high hardness and elastic modulus of the product, and the adhesion to the dual surface is not good under braking pressure. The fit of normal vulcanized products is good, the real contact area of the friction surface is small, and the friction coefficient of the material is low. In the examples, the dynamic friction coefficient is 0.17-0.18, and the static friction coefficient is 0.23-0.24. The contact of the asperities on the surface of the material can easily scratch the surface of the material, resulting in a high wear rate. In the example, the wear rate of the material reaches 8×10 ^-8 m ³ /J.

The Chinese patent with the publication number CN100572488C discloses a friction material and its preparation method. The main components of the paper-based friction material in its formula are: 20% to 50% of carbon fiber or aramid fiber, and 15% to 15% of cotton wool pulp. 20%, graphite 5%~10%, diatomaceous earth and silicon dioxide 5%~10%, friction modifier 4%~20%, cashew nut shell oil modified phenolic resin 15%~35%, colorant 0%~ 3%; The main components of the rubber cork friction material are: 60% to 80% of nitrile rubber, resin and cork, 2% to 10% of friction modifier, 5 to 10% of graphite, 1% to 5% of silicon dioxide %, diatomite 2% to 5%, alumina 1% to 5%, friction powder 2% to 5%, sepiolite 1% to 5%. The technical proposal of the patent is that a friction material includes a lining, a paper-based friction material, and a rubber cork friction material. In this patent, paper-based friction material and rubber cork-type friction material are prepared separately, and then the two are mixed and pressed on the lining at a temperature of 200-300°C, a pressure of 3-10 MPa, and a time of no more than 1 minute. The volume ratio of the paper-based friction material to the rubber cork friction material is 1:1-5, and finally cured at 140-180° C. for 2-6 hours to obtain the friction material. This method needs to prepare paper-based friction material and rubber cork friction material separately, the process cycle is long, the process is complicated, and the volume ratio control of the two materials is required to be precise. When the volume ratio of paper-based friction material and rubber cork friction material is greater than 1 : In 5 o'clock, the beneficial effect of the invention cannot be realized. According to the standard requirements of GB/T13826-2008, the coefficient of dynamic friction of this type of material must be greater than 0.15, and the coefficient of static friction must not be less than 0.24, but the measured dynamic and static coefficients of some embodiments of the patent are low, which cannot meet the above standard requirements , and at the same time, the wear rate of the friction material is relatively high, up to 6×10 ^-8 cm ³ /J.

Contents of the invention

technical problem to be solved

In order to avoid the shortcomings of the prior art, the present invention proposes a cork particle blended modified rubber-based friction material and its preparation method and use method. By increasing the mass percentage of rubber and optimizing it with other components, The invention overcomes the problems of low friction coefficient and high material wear rate of existing rubber-based friction materials.

Technical solutions

A cork particle blended modified rubber-based friction material, characterized in that the components are: silane coupling agent modified cork particle 20-35wt%, rubber 10-35wt%, organic resin binder 4-8wt%, inorganic 6-10% by weight of organic reinforcing fiber, 9-25% by weight of friction modifier and filler, and 2-7% by weight of rubber auxiliary agent; the sum of weight percentages of each component in the composition is 100%.

The silane coupling agent-modified cork particles are prepared from the cork layer of the bark part of the cork oak, with a particle size of 60 mesh, and are impregnated and modified with the silane coupling agent.

The rubber is granular solid, and one or more mixtures of nitrile rubber, fluorine rubber or styrene-butadiene rubber are used.

The organic resin binder is one or more mixtures of cashew nut shell oil modified phenolic resin, boron modified phenolic resin or nitrile rubber modified phenolic resin.

The rubber auxiliary agent is a mixture of sublimated sulfur and vulcanizing agent DCP, and then adding three or more mixtures of accelerator DM, accelerator CZ, zinc oxide, stearic acid or antioxidant MB.

The inorganic and organic reinforcing fibers are a mixture of carbon fiber and one of aramid fiber, glass fiber, calcium sulfate whisker or phenolic fiber.

The friction modifier is one or more mixtures of aluminum oxide, silicon dioxide, zinc oxide, iron powder and flake graphite.

The filler is black rubber powder, kaolin or barium sulfate.

A method for preparing any one of the cork particle blended modified rubber-based friction materials, characterized in that the steps are as follows:

Step 1: 20% to 35% of cork particles modified by silane coupling agent, 10% to 35% of rubber, 4% to 8% of organic resin binder, 6% to 10% of inorganic and organic reinforcing fibers, friction performance adjustment 9% to 25% of additives and fillers, and 2% to 7% of rubber additives are mixed, and added between the rollers of an open rubber mixer to obtain a flat preform; , time 5-7 minutes;

Step 2: The flat prefabricated body is cured by hot pressing on a flat vulcanizing machine, and the hot pressing process parameters are: temperature 160° C.; pressure 5-10 MPa.

A method for preparing a lining plate for a motorcycle clutch by using the friction material, which is characterized in that: cutting and bonding according to the specifications of the lining plate for a motorcycle clutch, putting it into a flat vulcanizing machine for hot-press forming, the hot-pressing process The parameters are: temperature 160°C; pressure 5-7MPa; follow-up heat treatment, follow-up heat treatment: the room temperature is raised to 140°C for 1 hour, then the temperature is raised to 155°C for 1 hour, and then it is naturally lowered to room temperature.

Beneficial effect

The invention proposes a cork particle blended modified rubber-based friction material and its preparation method and use method, which are modified by using high-temperature-resistant nitrile rubber, fluororubber, high-strength aramid fiber and carbon fiber, and silane coupling agent The cork particles are used together with a variety of friction modifiers and fillers of composite components to obtain a friction material with a high friction coefficient and low wear rate. The added cork particles are made from the cork layer of the cork oak bark. It has a unique cell structure that makes it have excellent properties such as light weight, good elasticity, softness, and wear resistance; the silane coupling agent can be combined with resins, rubbers, etc. The combination of organic materials and inorganic materials is a low-molecular organosilane, which can be used to modify cork particles and add them to friction materials, which can form molecular bridges between organic and inorganic components through physical or chemical reactions. The combination of the two can enhance the interface bonding between the resin, reinforcing fiber and filler in the friction material, improve the strength and toughness of the matrix, increase the dynamic and static friction coefficient, and reduce the wear rate of the material; The "bridging" effect of the coupling agent forms a "polymer alloy" structure in the friction material, which improves the bond energy, disperses and balances the stress when the material is subjected to an external force during the friction process, and prevents the crack expansion of the material, thereby achieving the toughening effect. Calcium sulfate whisker is a new type of reinforcing material, which has dual special functions of reinforcing fiber and powder filler. It has excellent properties such as heat resistance, wear resistance, and corrosion resistance. Its cost is lower than other types of whiskers. Adding whiskers The wear performance of the friction material can be improved. The heat resistance of nitrile rubber is superior to other rubbers, and it has similar solubility parameters to phenolic resins. The technical solution uses powdered rubber to simplify the mixing process and shorten the production process cycle; The production process combined with the flat vulcanizing machine simplifies the production process and improves the controllability of the production process. When the mass percentage of the nitrile rubber component is 10% to 35%, the dynamic friction coefficient of the rubber-based friction material is increased from 0.17 to 0.19 in the prior art to 0.23 to 0.26, and the static friction coefficient is increased from 0.23 to 0.26 in the prior art The ratio D/S of the coefficient of dynamic friction to the coefficient of static friction can reach 0.66-0.86, and the wear rate is reduced from 7×10 ^-8 cm ³ /J in the prior art to 3×10 ^-8 cm ³ /J.

Description of drawings

Figure 1: SEM images of the surface of the cork particle blended modified rubber-based friction material prepared in Example 2.

Figure 2: SEM images of the surface of the cork particle blended modified rubber-based friction material prepared in Example 4.

Detailed ways

Now in conjunction with embodiment, accompanying drawing, the present invention will be further described:

Example 1:

1) Weigh 4g of cashew nut shell oil modified phenolic resin, 20g of nitrile rubber, 2g of fluororubber, 16g of black rubber powder, 5g of aramid fiber, 1g of carbon fiber, 30g of cork particles, 2g of vulcanizing agent DCP, 1g of sublimated sulfur, and accelerator DM1g, accelerator CZ1g, zinc oxide 3g, aluminum oxide 3g, barite 5g, silicon dioxide 4g, iron powder 3g. Put the above raw materials into a small mixer and mix them in 3 times, each mixing time should not exceed 10 seconds, and each mixing interval should be 3 minutes until the mixing is uniform;

2) Add the mixed material from less to more between the rollers of the open rubber mixer for mixing, and mix repeatedly at room temperature for 5 minutes, thin pass more than 20 times to obtain a uniform flat preform, and the kneading is over;

3) Measure the thickness of the preform obtained in step 2) with a vernier caliper, and perform hot-press curing on a flat vulcanizing machine at 160°C and 10MPa;

4) The rubber obtained in step 3) is cut and bonded according to the size of the liner for the motorcycle clutch, and put into a flat vulcanizer for hot pressing;

5) The product obtained in step 4) was heat-treated at 140° C. for one hour, then raised to 155° C. for half an hour and heat-treated for one hour to obtain a cork particle blended modified rubber-based friction material.

The QM1000-ⅡB wet friction performance testing machine was used to test according to the GB/T13826-2008 standard, and the dynamic friction coefficient was 0.20-0.24, the static friction coefficient was 0.34-0.35, and the wear rate was less than 3×10 ^-8 cm ³ /J.

Example 2:

1) Weigh 4g of nitrile rubber modified phenolic resin, 25g of nitrile rubber, 3g of fluorine rubber, 12g of black rubber powder, 5g of aramid fiber, 1g of phenolic fiber, 28g of cork particles, 2.5g of vulcanizing agent DCP, and 1.5g of sublimated sulfur g, accelerator CZ 1g, stearic acid 1g, antioxidant MB 1g, alumina 2g, kaolin 5g, barium sulfate 4g, silicon dioxide 4g. Put the above raw materials into a small mixer and mix 3 times, each mixing time is no more than 10 seconds, and the mixing interval is 3 minutes until the mixing is uniform;

2) Gradually add the mixed material between the rollers of the open rubber mixing machine from less to more for mixing, and mix repeatedly at room temperature for 6 minutes, thin pass more than 20 times to obtain a uniform flat preform, and the kneading is over;

3) Measure the thickness of the preform obtained in step 2) with a vernier caliper, and perform hot-press curing on a flat vulcanizing machine at 160°C and 10MPa;

4) The rubber obtained in step 3) is cut and bonded according to the specifications of the liner for the motorcycle clutch, and put into a flat vulcanizing machine for hot pressing;

5) The product obtained in step 4) was heat-treated at 140° C. for one hour, then raised to 155° C. for half an hour and heat-treated for one hour to obtain a cork particle blended modified rubber-based friction material.

The QM1000-ⅡB wet friction performance testing machine was used to test according to the GB/T13826-2008 standard, and the dynamic friction coefficient was 0.19-0.23, the static friction coefficient was 0.29-0.31, and the wear rate was less than 2×10 ^-8 cm ³ /J.

Example 3:

1) Weigh 4g of cashew nut shell oil modified phenolic resin, 30g of nitrile rubber, 3g of styrene-butadiene rubber, 9g of black rubber powder, 5g of aramid fiber, 1g of carbon fiber, 2g of calcium sulfate whisker, 27g of cork particles, and 3g of vulcanizing agent DCP , sublimed sulfur 1g, stearic acid 1g, antioxidant MB 1g, accelerator CZ 1g, zinc oxide 2g, silicon dioxide 3g, flake graphite 3g, barium sulfate 3g, aluminum oxide 1g. Put the above raw materials into a small mixer and mix 3 times, the mixing time should not exceed 10 seconds each time, and the mixing interval should be 3 minutes until the mixing is uniform;

2) Gradually add the mixed material between the rollers of the open rubber mixing machine from small to large for mixing, and mix repeatedly at room temperature for 5 minutes, thin pass more than 20 times to obtain a uniform flat preform, and the kneading is over;

3) Measure the thickness of the preform obtained in step 2) with a vernier caliper and perform hot-press curing on a flat vulcanizing machine at 160°C and 10MPa;

4) The rubber obtained in step 3) is cut and bonded according to the specifications of the liner for the motorcycle clutch, and put into a flat vulcanizing machine for hot pressing;

5) The product obtained in step 4) was heat-treated at 140° C. for one hour, then raised to 155° C. for half an hour and heat-treated for one hour to obtain a cork particle blended modified rubber-based friction material.

The QM1000-ⅡB wet friction performance testing machine was used to test according to the GB/T13826-2008 standard, and the dynamic friction coefficient was 0.20-0.25, the static friction coefficient was 0.35-0.36, and the wear rate was less than 3×10 ^-8 cm ³ /J.

Example 4:

1) Weigh 4g of boron modified phenolic resin, 35g of nitrile rubber, 9g of black rubber powder, 5g of aramid fiber, 1g of carbon fiber, 28.5g of cork particles, 3.5g of vulcanizing agent DCP, 1g of accelerator CZ, 1g of accelerator DM, sublimation Sulfur 1.5g, antioxidant MB 1g, stearic acid 0.5g, alumina 1g, kaolin 2g, barite 3g, silicon dioxide 3g. Put the above raw materials into a small mixer and mix 3 times, the mixing time should not exceed 10 seconds each time, and the mixing interval should be 3 minutes until the mixing is uniform;

2) Gradually add the mixed material between the rollers of the open rubber mixing machine from less to more for mixing, and mix repeatedly at room temperature for 7 minutes, thin pass more than 20 times to obtain a uniform flat preform, and the kneading is over;

3) Measure the thickness of the preform obtained in step 2) with a vernier caliper, and perform hot-press curing on a flat vulcanizing machine at 160°C and 10MPa;

4) The rubber obtained in step 3) is cut and bonded according to the specifications of the liner for the motorcycle clutch, and put into a flat vulcanizing machine for hot pressing;

5) The product obtained in step 4) was heat-treated at 140° C. for one hour, then raised to 155° C. for half an hour and heat-treated for one hour to obtain a cork particle blended modified rubber-based friction material.

The QM1000-ⅡB wet friction performance testing machine was used to test according to the GB/T13826-2008 standard, and the dynamic friction coefficient was 0.18-0.26, the static friction coefficient was 0.29-0.33, and the wear rate was less than 3×10 ^-8 cm ³ /J.

Claims (10)

1. A cork particle blended modified rubber-based friction material, characterized in that the components are: silane coupling agent modified cork particle 20-35wt%, rubber 10-35wt%, organic resin binder 4-8wt% 6-10wt% of inorganic and organic reinforcing fibers, 9-25wt% of friction modifiers and fillers, 2-7wt% of rubber additives; the sum of the weight percentages of each component in the composition is 100%. 2. The cork particle blended modified rubber-based friction material according to claim 1, characterized in that: the silane coupling agent modified cork particle is made from the cork layer of the cork oak bark part, and the particle size is 60 For this purpose, silane coupling agent was used for impregnation modification. 3. According to claim 1 or 3, the cork particle blended modified rubber-based friction material is characterized in that: the rubber is a granular solid, and one or one of nitrile rubber, fluororubber or styrene-butadiene rubber is used a mixture of the above. 4. The cork particle blended modified rubber-based friction material according to claim 1, characterized in that: the organic resin binder is cashew nut shell oil modified phenolic resin, boron modified phenolic resin or nitrile rubber modified One or more mixtures of phenolic resins. 5. The cork particle blended modified rubber-based friction material according to claim 1, characterized in that: the rubber auxiliary agent is a mixture of sublimated sulfur and vulcanizing agent DCP, and then adding accelerator DM, accelerator CZ, zinc oxide, A mixture of three or more of stearic acid or antioxidant MB. 6. The cork particle blended modified rubber-based friction material according to claim 1, characterized in that: the inorganic and organic reinforcing fibers are one of carbon fiber, aramid fiber, glass fiber, calcium sulfate whisker or phenolic fiber mixture. 7. The cork particle blended modified rubber-based friction material according to claim 1, characterized in that: the friction performance modifier is one of alumina, silicon dioxide, zinc oxide, iron powder and flake graphite or a mixture of more than one. 8. The cork particle blended modified rubber-based friction material according to claim 1, characterized in that: the filler black rubber powder, kaolin or barium sulfate. 9. A method for preparing any one of the cork particle blended modified rubber-based friction materials according to claims 1 to 7, characterized in that the steps are as follows: Step 1: 20% to 35% of cork particles modified by silane coupling agent, 10% to 35% of rubber, 4% to 8% of organic resin binder, 6% to 10% of inorganic and organic reinforcing fibers, friction performance adjustment 9% to 25% of additives and fillers, and 2% to 7% of rubber additives are mixed, and added between the rollers of an open rubber mixer to obtain a flat preform; , time 5-7 minutes; Step 2: The flat prefabricated body is cured by hot pressing on a flat vulcanizing machine, and the hot pressing process parameters are: temperature 160° C.; pressure 5-10 MPa. 10. A method for preparing a lining plate for a motorcycle clutch using the friction material according to claim 9, characterized in that: cutting and bonding according to the size of the lining plate for a motorcycle clutch, putting it into a flat vulcanizing machine for hot pressing Forming and hot pressing process parameters are: temperature 160°C; pressure 5-7MPa; follow-up heat treatment, follow-up heat treatment: room temperature rises to 140°C for 1 hour, then heats up to 155°C for 1 hour, and then naturally drops to room temperature.