The oil seal is usually used to seal the lubricating oil. The purpose is to isolate the parts that need to be lubricated from the transmission parts and avoid the leakage of lubricating oil. Nitrile rubber is the most commonly used rubber raw material for oil seal products, with high cost performance. At present, many manufacturers of nitrile oil seals still use recycled nitrile rubber in the oil seals, or even completely use nitrile rubber. Among them, the nitrile oil seal formula directly determines the performance and life of the oil seal. So how to design a nitrile rubber / recycled rubber oil seal formulation to improve oil seal performance? What problems should we pay attention to?
1. Factors to consider when designing a nitrile oil seal formula
When using nitrile rubber, nitrile rubber or nitrile rubber / recycled rubber alone and using rubber to produce oil seal products, rubber product manufacturers need to combine the specific performance requirements of oil seals, mainly including oil resistance, heat resistance, wear resistance, compression and permanent Deformation, hardness, etc. ① In general, the hardness of the nitrile oil seal is better controlled at 75 Shore hardness; ② The friction temperature of the lip of the oil seal will be 20-30 ° C higher than the oil temperature, or even higher. It is necessary to improve the heat resistance of the rubber to avoid the oil seal 2LLYY0304 Early damage due to high temperature.
2.Cooperating system for improving various properties of nitrile oil seal
(1) When nitrile rubber / recycled rubber is used to produce oil seal products, the hardness of the oil seal is generally adjusted through the combination of the reinforcement system and the plasticization system. You can try to mix a variety of carbon blacks with high wear resistance, semi-reinforced carbon black, and Use carbon black together, adjust the amount of carbon black in different types of carbon black, or add or subtract plasticizers appropriately.
(2) Improving the heat aging resistance of the nitrile oil seal can be achieved by adjusting the oil seal vulcanization system. In general, the vulcanized compounds such as low-sulfur high-acid vulcanization systems, peroxide vulcanization systems, sulfur / sulfide-peroxide blend systems, and cadmium-magnesium vulcanization systems have better heat aging resistance. Nitrile rubber / recycled rubber oil seal formulations can also use magnesium methacrylate as a vulcanization aid when vulcanized with peroxide DCP to improve rubber heat resistance.
The use of white carbon in the nitrile oil seal reinforcement system can also improve the heat resistance of the compound to a certain extent.
(3) When part of the nitrile rubber is used instead of nitrile rubber to produce oil seal products, rubber product manufacturers also need to combine the indicators of oil seals with the rubber content, tensile strength and other indicators of the nitrile rubber to reasonably determine The added proportion reduces the low cost on the premise of ensuring quality.
At present, oil seals on the market include polyacrylate rubber oil seals, fluorine rubber oil seals, etc., but due to the high cost of raw materials, nitrile rubber oil seals still occupy the main market. Continuously studying the formulation technology of nitrile rubber oil seals and improving the quality of recycled nitrile rubber can expand the scope of use of nitrile rubber, increase the proportion of use, and finally give oil seal manufacturers higher market competitiveness and more objective economic benefits.