Nitrile reclaimed rubber is made from waste nitrile rubber and used nitrile rubber products. It retains the core performance features of nitrile rubber and is mainly used in the production of various oil-resistant rubber products. Many rubber parts that come into contact with engine oil, diesel, or lubricating oil use either nitrile reclaimed rubber or a mix of nitrile rubber and nitrile reclaimed rubber, such as oil seals, oil-resistant hoses, oil-resistant conveyor belts, and oil-resistant sealing strips. So why can nitrile reclaimed rubber become a core material for oil-resistant rubber products in actual production?
1. Molecular structure characteristics of nitrile reclaimed rubber
From a molecular perspective, nitrile rubber has strong polar cyano groups on its main chain, making it the most polar type of general-purpose rubber. Nitrile reclaimed rubber retains this core structural advantage. Polar nitrile reclaimed rubber has very poor compatibility with non-polar mineral oils and fuels, so oil cannot easily penetrate the rubber, which gives it excellent resistance to non-polar oils. Its oil resistance is better than other reclaimed rubbers like chloroprene or natural rubber, meeting the basic oil resistance requirements for oil-resistant rubber products.
The electron-withdrawing effect of the cyano groups in nitrile reclaimed rubber reduces the degree of unsaturation in the molecules, making the hydrogens in allylic positions stable. This gives it good heat stability. In the production of oil-resistant rubber products like E6LYY318, it does not easily degrade or fail when exposed to high-temperature oil for long periods. It can also be blended with nitrile rubber to produce high-temperature oil-resistant products like engine oil seals and fuel hoses. The cyano groups and the trans-1,4 structure make a tight molecular structure with low gas permeability, giving it good airtightness. Its polarity also increases intermolecular forces, resulting in good wear resistance.
2. Processing advantages of nitrile reclaimed rubber
Nitrile rubber itself has narrow molecular weight distribution, high polarity, poor chain flexibility, and specific chemical structure, which leads to poor processing performance. It is difficult to plasticize and mix, generates high heat during mixing, shows significant shrinkage and expansion during calendering or extrusion, has poor self-adhesion during molding, and vulcanizes slowly.
Compared with pure nitrile rubber, nitrile reclaimed rubber has good and stable plasticity, with additives evenly dispersed. It requires much less power during mixing. It also acts as a lubricant, making sheet extrusion and molding easier for rubber mixed with it. Unvulcanized rubber with nitrile reclaimed rubber shows much smaller expansion and shrinkage than pure new rubber, resulting in more accurate shapes and dimensions—a critical factor for oil-resistant sealing products.
3. Common applications of nitrile reclaimed rubber in oil-resistant rubber products
Nitrile reclaimed rubber exhibits the basic characteristics of rubber and excellent oil resistance, making it widely used in various oil-resistant products. High to mid acrylonitrile content nitrile reclaimed rubber can be blended with nitrile rubber to produce products that directly contact oils and require high oil resistance, such as oil seals, fuel hoses, chemical container linings, gaskets, oil-resistant hoses, fuel tanks, and printing rollers. Lower acrylonitrile content nitrile and reclaimed rubber can be used for products with moderate oil resistance needs, such as low-temperature oil-resistant items and oil-resistant shock absorbers. Nitrile reclaimed rubber can also be combined with plastics, with PVC being the most common, further improving oil, ozone, and aging resistance.
Nitrile reclaimed rubber has excellent oil resistance, good heat and wear resistance, and is an ideal option to pure nitrile rubber for producing various oil-resistant products. By selecting the right nitrile reclaimed rubber and appropriately adjusting the formulation and processing parameters, more performance- and cost-competitive oil-resistant rubber products can be manufactured.
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