Engine lubricating oil is by no means a single-component liquid. In order to meet the multiple needs of lubrication, heat dissipation, cleaning, etc. of the engine under different working conditions, manufacturers add a variety of functional additives such as antioxidants, anti-wear agents, detergents and dispersants. These additives not only improve the comprehensive performance of lubricating oil, but also make the chemical properties of lubricating oil complex and active. In addition, during the operation of the engine, the lubricating oil will undergo a series of physical and chemical changes due to high temperature, high pressure and interaction with metal parts, which further aggravates its corrosiveness to the oil seal material.
NBR, or nitrile rubber, has a unique molecular structure that is the key to resisting the erosion of lubricating oil. The molecular chain of NBR rubber contains polar nitrile groups. This structural feature makes the affinity between NBR and oil molecules extremely low. From a chemical point of view, the affinity between substances often determines the degree of their interaction. In the contact between NBR and engine lubricating oil, due to the low affinity between nitrile groups and oil molecules, various molecules in the lubricating oil are difficult to penetrate into the molecular network of NBR rubber. This molecular-level "repulsion" effect fundamentally prevents the swelling process of the lubricant on the NBR oil seal.
Swelling is extremely common for ordinary rubber materials. When ordinary rubber oil seals come into contact with engine lubricants, the oil molecules will gradually diffuse into the molecular gaps of the rubber, causing the rubber volume to expand and soften, and then lose its original physical properties and sealing ability. But NBR wear-resistant automotive parts oil seals are completely different. Due to its strong resistance to swelling of lubricants, NBR oil seals can always maintain their shape and dimensional stability during long-term contact with lubricants. Whether in extreme environments where the lubricant temperature soars to 100°C or even higher when the engine is running at high temperature, or in complex working conditions where the engine is frequently started and stopped and the lubricant pressure fluctuates frequently, NBR oil seals can hold their ground.
In addition to resisting swelling, NBR rubber is also excellent in resistance to lubricant erosion. Additives and chemicals in engine lubricants may react chemically under high temperature and pressure to produce corrosive substances. If these corrosive substances react with the oil seal material, they will destroy the molecular structure of the oil seal and deteriorate its performance. However, the nitrile group in NBR rubber can effectively resist the attack of these corrosive substances by virtue of its own chemical stability. The presence of nitrile groups makes NBR rubber more stable in chemical properties and not easy to react chemically with the corrosive components in the lubricating oil, thus ensuring that the oil seal will not soften, deform or lose elasticity due to chemical erosion during long-term use.
The excellent oil resistance of NBR wear-resistant automotive parts oil seal directly translates into excellent sealing effect. Throughout the service life of the engine, NBR oil seals can always maintain a tight fit with key components such as crankshafts and camshafts. Whether the engine is in different operating states such as idling, high-speed driving, rapid acceleration, and rapid deceleration, NBR oil seals can adapt to the slight displacement and vibration of the journal and maintain a stable sealing pressure. This not only effectively prevents the leakage of lubricating oil, ensures the normal lubrication environment inside the engine, and ensures that all components operate smoothly under good lubrication conditions, but also greatly improves the reliability and durability of the engine.
NBR wear-resistant automotive parts oil seals have a unique molecular structure, especially the polar nitrile group in the molecular chain, which shows extraordinary oil resistance when facing complex and corrosive engine lubricants. This performance enables NBR oil seals to always maintain stable physical properties and excellent sealing effects in long-term harsh working environments, making them the only choice for crankshaft and camshaft oil seals in automobile engines, providing a solid and reliable guarantee for the efficient and stable operation of automobile engines.
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