A self-lubricating ethylene propylene diene monomer rubber and its preparation method and application

Abstract

The present invention relates to a self-lubricating ethylene propylene diene monomer rubber and its preparation method and application. The components and their mass parts are as follows: ethylene propylene diene monomer rubber: 100 parts, fast extrusion carbon black: 50 - 80 parts, paraffin oil: 5 - 40 parts, ester plasticizer: 2 - 5 parts, oleic acid amide: 12 - 20 parts, zinc oxide: 4 - 6 parts, stearic acid: 1 - 3 parts, 2-mercaptobenzothiazole: 0.5 - 2 parts, zinc dibutyldithiocarbamate: 0.5 - 2 parts, tetramethylthiuram disulfide: 0.5 - 1 part, tetramethylthiuram tetrasulfide: 0.5 - 1 part, sulfur: 0.5 - 2 parts. The product of the present invention will exhibit a self-lubricating effect in a very short time. In a dynamic use environment, even when the lubricant is continuously consumed, it can still quickly, long-term, and continuously precipitate the lubricant to ensure a continuously low friction resistance effect in the dynamic environment.

Description

[0001] This application is a divisional application. The application number of the original application is: "202111035207.9", the application date is: "September 5, 2021", and the invention title is: "A self-lubricating ethylene propylene diene monomer rubber and its preparation method". Technical Field

[0002] The present invention relates to the field of ethylene propylene diene monomer rubber, and particularly to a self-lubricating ethylene propylene diene monomer rubber and a preparation method thereof. Background Art

[0003] Due to their large elasticity and deformation ability, rubber products usually exhibit a relatively high coefficient of friction. This characteristic causes rubber products to generate a large resistance to rotation and sliding when used in some dynamic environments (such as in the automotive and machinery industries, some rotating and sealed parts). As a result, it is easy to accelerate the wear of the product itself, while increasing the energy consumption required to maintain the movement and increasing the burden on the operation of the entire system.

[0004] To solve the above problems, using self-lubricating rubber to replace traditional rubber is an effective solution. However, currently, most self-lubricating rubbers are designed for easy assembly and sliding. Their lubricating effect is weak, and either they cannot take effect quickly or their duration is very short. These situations result in the original self-lubricating rubber being unable to be applied to parts that continuously slide and rotate, making the operation of the entire system compliant large and the lifespan short. Summary of the Invention

[0005] The purpose of the present invention is to provide a self-lubricating rubber that can maintain a good lubricating effect for a long time. Through reasonable proportioning ratios and reasonable selection and proportioning of lubricants, the product can maintain a good lubricating effect for a long time. In addition, through a specific processing method, the formulation can be successfully mixed. Thus, the efficient use of self-lubricating rubber is satisfied.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The present invention provides a self-lubricating ethylene propylene diene monomer rubber, and its components and mass fractions are as follows:

[0008]

[0009]

[0010] Preferably, the ester plasticizer is plasticizer Rohm and Haas TP-95.

[0011] In the present invention, ethylene propylene diene monomer rubber, fast extrusion carbon black, paraffin oil, and stearic acid are all general-purpose materials, and conventional materials on the market can be used.

[0012] In the present invention, zinc oxide is indirect method zinc oxide or active zinc oxide.

[0013] In the present invention, M, BZ, TMTD, DPTT, and S are general-purpose materials.

[0014] The preparation method of the self-lubricating ethylene propylene diene monomer (EPDM) rubber of the present invention comprises the following steps:

[0015] (1) Weigh all raw materials: among them, carbon black is weighed in two equal parts, and the rest of the raw materials are weighed separately;

[0016] (2) Put the EPDM rubber into a kneader and knead for (120 ± 20) s; put in half of the carbon black, zinc oxide, stearic acid, and oleic acid amide for kneading, and the kneading time is (300 ± 50) s; put the remaining carbon black, paraffin oil, and ester plasticizer into the kneader for kneading at the same time, knead until 115 °C - 120 °C, and discharge the rubber;

[0017] (3) Let the above-mentioned mixed rubber compound stand at room temperature for 12 - 36 h, put it into a kneader, after kneading for (30 ± 10) s, put in M, BZ, TMTD, DPTT, and S, and continue to knead until 80 °C - 100 °C, and discharge the rubber;

[0018] (4) Pass the above-mentioned mixed rubber compound through a two-roll mill for 3 - 5 times, and then cut it into sheets according to the required size.

[0019] The present invention also provides the application of the above-mentioned self-lubricating EPDM rubber in the dynamic environment of the automotive or mechanical industry.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1) The formulation system in the present invention is applicable to EPDM rubber. The ester plasticizer in the formulation plays a role in rapid lubrication: by virtue of its poor compatibility with EPDM rubber, the ester plasticizer will quickly ooze out to the surface of the product in the initial stage of product use, forming a lubricating film. At the same time, it can accelerate the oozing speed of the subsequent lubricant, playing an initial transition role. Oleic acid amide, as a persistent lubricant, has slightly better compatibility with EPDM rubber and a slower oozing speed, so it can continuously ooze out for a long time to play a lubricating role. Since oleic acid amide is solid and has a good combination with the rubber surface, but its lubricating effect is slightly worse than that of the ester plasticizer, a relatively large amount of oleic acid amide is added in the present invention to ensure sufficient lubricating effect during the use of the product. In addition, through the ratio of several materials in the present invention, an appropriate crosslinking density is formed to ensure a reasonable oozing speed of the lubricant.

[0022] 2) In the present invention, the material ratio can achieve good mixing and usage effects when kneaded according to a specific preparation method. Compared with the prior art, it has the following advantages: The product prepared from the formula in the present invention will exhibit self-lubricating effects in a very short time. In a dynamic usage environment, even when the lubricant is continuously consumed, the lubricant can still be rapidly, long-term, and continuously precipitated to ensure a continuously low friction resistance effect in the dynamic environment. Detailed implementation manners

[0023] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0024] Embodiment 1:

[0025] A self-lubricating ethylene propylene diene monomer (EPDM) rubber, the components and their mass parts are as follows:

[0026]

[0027] The above formula is kneaded according to the following process:

[0028] (1) Weigh all the raw materials: Among them, carbon black is weighed in two equal parts, and the rest of the raw materials are weighed separately;

[0029] (2) Put the EPDM rubber into a kneader and knead for 120S; put in half of the carbon black, zinc oxide, stearic acid and oleic acid amide for kneading, and the kneading time is 300S; put the remaining carbon black, paraffin oil and ester plasticizer into the kneader for kneading at the same time, knead until 120 °C, and discharge the rubber.

[0030] (3) Let the above mixed rubber compound stand at room temperature for 24h, put it into the kneader, after kneading for 30S, put in M, BZ, TMTD, DPTT, S, and continue to knead until 100 °C, and discharge the rubber.

[0031] (4) Pass the above mixed rubber compound through the roll mill 5 times and take off the sheet.

[0032] For the material in this embodiment, tested according to ASTM1894, the dynamic friction coefficient is 0.075. After aging at 100 °C for 168h, clean the surface of the specimen, and then place it at room temperature for 24h, and then test according to ASTM1894, the dynamic friction coefficient is 0.119.

[0033] The product made of the material prepared according to the formula and preparation method of the above embodiment is installed at the dynamic sealing part of the automobile cooling system valve. The initial torque is 0.7 Nm. After continuous dynamic friction for 20,000 circles, the friction rotation torque between the rubber part and the injection part is 1.2 Nm. After 40,000 circles, the friction rotation torque between the rubber part and the injection part is less than 1.8 Nm. After 70,000 circles, the friction rotation torque between the rubber part and the injection part is less than 2.8 Nm, and there is no leakage throughout the process.

[0034] Example 2:

[0035] A self-lubricating ethylene propylene diene monomer (EPDM) rubber, and its components and mass parts are as follows:

[0036]

[0037] The above formula is kneaded according to the following process:

[0038] (1) Weigh all raw materials: among them, carbon black is weighed in two equal parts, and the rest of the raw materials are weighed separately;

[0039] (2) Put the EPDM rubber into a kneader and knead for 100 s; put in half of the carbon black, zinc oxide, stearic acid and oleic acid amide for kneading, and the kneading time is 250 s; put the remaining carbon black, paraffin oil and ester plasticizer into the kneader for kneading at the same time, knead until 115 °C, and discharge the rubber.

[0040] (3) Let the above mixed rubber compound stand at room temperature for 12 h, put it into a kneader, after kneading for 20 s, put in M, BZ, TMTD, DPTT, S, and continue to knead until 80 °C, and discharge the rubber.

[0041] (4) Pass the above mixed rubber compound through a two-roll mill 3 times, and then cut it into sheets according to the required size.

[0042] For the materials in this example, tested according to ASTM1894, the dynamic friction coefficient is 0.056. After aging at 100 °C for 168 h, clean the surface of the specimen, and then place it at room temperature for 24 h, and then test according to ASTM1894, the dynamic friction coefficient is 0.092.

[0043] The product made of the material prepared according to the formula and preparation method of the above example is installed at the dynamic sealing part of the automobile cooling system valve. The initial torque is 0.6 Nm. After continuous dynamic friction for 20,000 circles, the friction rotation torque between the rubber part and the injection molded part is 0.9 Nm. After 40,000 circles, the friction rotation torque between the rubber part and the injection molded part is less than 1.4 Nm. After 70,000 circles, the friction rotation torque between the rubber part and the injection molded part is less than 2.5 Nm, and there is no leakage throughout the process.

[0044] Example 3:

[0045] A self-lubricating ethylene propylene diene monomer (EPDM) rubber, and its components and mass parts are as follows:

[0046]

[0047] (1) Weigh all raw materials: among them, carbon black is weighed in two equal parts, and the rest of the raw materials are weighed separately;

[0048] (2) Put ethylene propylene diene monomer rubber into a kneader and knead for 140 s; put in half of the carbon black, zinc oxide, stearic acid and oleic acid amide and knead. The kneading time is 350 s; put the remaining carbon black, paraffin oil and ester plasticizer into the kneader at the same time and knead until the temperature reaches 120 °C, then discharge the rubber.

[0049] (3) Let the above-mentioned mixed rubber compound stand at room temperature for 24 h, put it into a kneader, after kneading for 40 s, put in M, BZ, TMTD, DPTT, S, and continue kneading until the temperature reaches 100 °C, then discharge the rubber.

[0050] (4) Pass the above-mentioned mixed rubber compound through a roll mill 5 times, and then cut it into sheets according to the required dimensions.

[0051] The materials in this example, when tested according to ASTM1894, have a dynamic friction coefficient of 0.087. After aging at 100 °C for 168 h, clean the surface of the test specimen, and then place it at room temperature for 24 h. When tested according to ASTM1894, the dynamic friction coefficient is 0.125.

[0052] The products made of the materials prepared according to the formula and preparation method of the above example are installed at the dynamic sealing part of the valve of the automobile cooling system. The initial torque is 0.7 Nm. After continuous dynamic friction for 20,000 circles, the friction rotation torque between the rubber part and the injection molded part is 1.1 Nm. After 40,000 circles, the friction rotation torque between the rubber part and the injection molded part is less than 1.6 Nm. After 70,000 circles, the friction rotation torque between the rubber part and the injection molded part is less than 2.7 Nm, and there is no leakage throughout the process.

[0053] Example 4

[0054] A self-lubricating ethylene propylene diene monomer rubber, and its components and mass fractions are as follows:

[0055]

[0056] (1) Weigh all the raw materials: divide the carbon black into two equal parts for weighing, and weigh the rest of the raw materials separately;

[0057] (2) Put ethylene propylene diene monomer rubber into a kneader and knead for 140 s; put in half of the carbon black, zinc oxide, stearic acid and oleic acid amide and knead. The kneading time is 300 s; put the remaining carbon black, paraffin oil and ester plasticizer into the kneader at the same time and knead until the temperature reaches 120 °C, then discharge the rubber.

[0058] (3) Let the above-mentioned mixed rubber compound stand at room temperature for 24 h, put it into a kneader, after kneading for 35 s, put in M, BZ, TMTD, DPTT, S, and continue kneading until the temperature reaches 110 °C, then discharge the rubber.

[0059] (4) Pass the above-mentioned mixed rubber compound through a roll mill 5 times, and then cut it into sheets according to the required dimensions.

[0060] In this example, the coefficient of dynamic friction of the material is 0.081 when tested according to ASTM1894. After aging at 100 °C for 168 h, the surface of the sample was cleaned, and then after standing at room temperature for 24 h, the coefficient of dynamic friction was 0.117 when tested according to ASTM1894.

[0061] The product made of the material prepared according to the formula and preparation method of the above example is installed at the dynamic sealing part of the valve of the automobile cooling system. The initial torque is 0.6 Nm. After continuous dynamic friction for 20,000 circles, the friction rotation torque between the rubber part and the injection molded part is 1.0 Nm. After 40,000 circles, the friction rotation torque between the rubber part and the injection molded part is less than 1.6 Nm. After 70,000 circles, the friction rotation torque between the rubber part and the injection molded part is less than 2.6 Nm, and there is no leakage throughout the process.

[0062] Example 5

[0063]

[0064]

[0065] (1) Weigh all the raw materials: the carbon black is weighed in two equal parts, and the rest of the raw materials are weighed separately;

[0066] (2) Put the ethylene propylene diene monomer rubber into the kneader and knead for 130 s; put in half of the carbon black, zinc oxide, stearic acid and oleic acid amide for kneading, and the kneading time is 330 s; put the remaining carbon black, paraffin oil and ester plasticizer into the kneader at the same time for kneading until 115 °C, and discharge the rubber.

[0067] (3) Let the above mixed rubber compound stand at room temperature for 36 h, put it into the kneader, after kneading for 35 s, put in M, BZ, TMTD, DPTT, S, and continue to knead until 110 °C, and discharge the rubber.

[0068] (4) Pass the above mixed rubber compound through the open mill 4 times, and then cut it into sheets according to the required size.

[0069] In this example, the coefficient of dynamic friction of the material is 0.062 when tested according to ASTM1894. After aging at 100 °C for 168 h, the surface of the sample was cleaned, and then after standing at room temperature for 24 h, the coefficient of dynamic friction was 0.126 when tested according to ASTM1894.

[0070] The product made of the material prepared according to the formula and preparation method of the above embodiment is installed at the dynamic sealing part of the valve of the automobile cooling system. The initial torque is 0.6 Nm. After 20,000 circles of continuous dynamic friction, the friction rotation torque between the rubber part and the injection-molded part is 0.9 Nm. After 40,000 circles, the friction rotation torque between the rubber part and the injection-molded part is less than 1.5 Nm. After 70,000 circles, the friction rotation torque between the rubber part and the injection-molded part is less than 2.7 Nm, and there is no leakage throughout the process.

[0071] Comparative Example 1: The solution described in CN110591237A

[0072]

[0073] For the material in this embodiment, tested according to ASTM1894, the dynamic friction coefficient is 0.236. After aging at 100 °C for 168 h, the surface of the sample is cleaned, and then after standing at room temperature for 24 h, tested according to ASTM1894, the dynamic friction coefficient is 0.218.

[0074] The product made according to this solution is installed at the dynamic sealing part of the valve of the automobile cooling system, and the initial rotation torque exceeds 5 Nm.

[0075] The lubrication effect of this solution is insufficient.

[0076] Comparative Example 2: Remove the ester plasticizer in the solution of the present invention, and the formula is as follows:

[0077]

[0078] For the material in this embodiment, after being made into a sample and standing for 24 h, tested according to ASTM1894, the dynamic friction coefficient is 0.189. After aging at 100 °C for 168 h, the surface of the sample is cleaned, and then after standing at room temperature for 24 h, tested according to ASTM1894, the dynamic friction coefficient is 0.178.

[0079] The product made according to this solution is installed at the dynamic sealing part of the valve of the automobile cooling system, with an initial torque of 3.2 Nm. After 20,000 circles of continuous dynamic friction, the friction rotation torque between the rubber part and the injection-molded part is 1.8 Nm, and leakage occurs.

[0080] Without the ester lubricating grease, the initial torque of the product is too large, and the product wears after 20,000 circles of friction, resulting in leakage.

[0081] Comparative Example 3: Reduce the amount of lubricant added in the solution of the present invention, and the formula is as follows:

[0082]

[0083]

[0084] In this embodiment, the material has a dynamic friction coefficient of 0.157 when tested according to ASTM1894. After aging at 100°C for 168 hours, the surface of the test specimen is cleaned, and then after standing at room temperature for 24 hours and tested according to ASTM1894, the dynamic friction coefficient is 0.322.

[0085] The product made according to this scheme is installed in the dynamic sealing part of the automobile cooling system valve. The initial torque is 0.8 Nm. After continuous dynamic friction for 20,000 circles, the friction rotation torque between the rubber part and the injection-molded part is 1.8 Nm. After 40,000 circles, the friction rotation torque between the rubber part and the injection-molded part is less than 2.6 Nm. After 60,000 circles, the torque exceeds 5 Nm, abnormal noise appears during rotation, and leakage occurs.

[0086] The amount of lubricant added is small, and the overall lubrication effect fails to meet the requirements. Moreover, the longer it lasts, the worse the lubrication effect becomes.

[0087] In summary, by using the formula and implementation method of the above embodiment, self-lubricating rubber that can maintain a good lubrication effect for a long time can be prepared. When the product is in a dynamic use environment and the lubricant is continuously consumed, the lubricant can still be rapidly, long-term, and continuously precipitated to ensure a continuous low-friction resistance effect in the dynamic environment.

Claims

1. A self-lubricating ethylene propylene diene monomer rubber, characterized in that: Its components and their parts by mass are as follows: The ester plasticizer mentioned is Rohm and Haas TP-95 plasticizer; The self-lubricating ethylene propylene diene monomer rubber is prepared by a method including the following steps: (1) Weigh all raw materials: among them, carbon black is weighed in two equal parts, and the rest of the raw materials are weighed separately; (2) Put ethylene propylene diene monomer rubber into a kneader and knead for 120S ± 20S; put in half of the carbon black, zinc oxide, stearic acid and oleic acid amide and knead. The kneading time is 300S ± 50S; put the remaining carbon black, paraffin oil and ester plasticizer into the kneader at the same time and knead until the temperature reaches 115°C - 120°C, then discharge the rubber; (3) Let the mixed rubber compound stand at room temperature for 12h - 36h, put it into the kneader, after kneading for 30S ± 10S, put in 2-mercaptobenzothiazole, zinc dibutyldithiocarbamate, tetramethylthiuram disulfide, dipentamethylenethiuram tetrasulfide, sulfur, and continue to knead until the temperature reaches 80°C - 100°C, then discharge the rubber; (4) Pass the mixed rubber compound through a two-roll mill for 3 - 5 passes and then take off the sheet.

2. The self-lubricating ethylene propylene diene monomer rubber according to claim 1, characterized in that: Its components and their parts by mass are as follows:

3. The self-lubricating ethylene propylene diene monomer rubber according to claim 1, characterized in that: Its components and their parts by mass are as follows:

4. A self-lubricating ethylene propylene diene monomer rubber according to claim 1, characterized in that: Its components and their parts by mass are as follows:

5. The preparation method of the self-lubricating ethylene propylene diene monomer rubber according to any one of claims 1-4, characterized in that: Including the following steps: (1) Weigh all raw materials: among them, carbon black is weighed in two equal parts, and the rest of the raw materials are weighed separately; (2) Put ethylene propylene diene monomer rubber into a kneader and knead for 120S ± 20S; put in half of the carbon black, zinc oxide, stearic acid and oleic acid amide and knead. The kneading time is 300S ± 50S; put the remaining carbon black, paraffin oil and ester plasticizer into the kneader at the same time and knead until the temperature reaches 115°C - 120°C, then discharge the rubber; (3) Let the mixed rubber compound stand at room temperature for 12h - 36h, put it into the kneader, after kneading for 30S ± 10S, put in 2-mercaptobenzothiazole, zinc dibutyldithiocarbamate, tetramethylthiuram disulfide, dipentamethylenethiuram tetrasulfide, sulfur, and continue to knead until the temperature reaches 80°C - 100°C, then discharge the rubber; (4) Pass the mixed rubber compound through a two-roll mill for 3 - 5 passes and then take off the sheet.

6. Application of the self-lubricating ethylene propylene diene monomer rubber according to any one of claims 1 - 4 in the dynamic environment of the automotive or mechanical industry.

7. Application of the self-lubricating ethylene propylene diene monomer rubber according to any one of claims 1 - 4 in the dynamic sealing part of the automotive cooling system valve.

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