Introduction to oil resistant hose

Oil-resistant hose in addition to meet the basic mechanical properties as a rubber hose requirements, the outstanding is to meet the oil resistance performance requirements. Rubber oil resistance refers to the vulcanised rubber resistance to the role of oil, that is, when rubber products and a variety of oil long-term contact, the oil can penetrate into the rubber to make it expand (or volume increase), or oil media can be drawn from the vulcanised rubber soluble cooperating agent (such as plasticiser), resulting in the vulcanised rubber contraction (or volume reduction). The oils used are motor oils, hydraulic oils, engine oils, fuel oils, and other oils. The evaluation of oil resistance is usually done by using standard test oil to determine the percentage change in volume (or mass) of the vulcanised rubber in the oil, at the specified temperature and time of immersion, or the percentage change in hardness (or difference).

The oil resistance of a vulcanised rubber depends mainly on the chemical properties of the rubber, the vulcanisation system and the oil used. Oil is usually non-polar, so rubber containing polar groups such as nitrile rubber, neoprene rubber, the polarity of the two large difference, non-polar oil has good stability. Furthermore, the vulcanisation system of rubber has an important influence on the improvement of oil resistance. Generally speaking, the oil resistance increases with the increase of crosslinking density, the reduction of free volume in the network structure and the oil penetration and diffusion difficulties, thus increasing the oil resistance. In addition, with the type of crosslinking bond is also related to the peroxide vulcanisation or effective sulfur vulcanisation of the rubber (such as nitrile rubber) than with ordinary sulfur vulcanisation system of the rubber's oil resistance is better. Carbon black as a filler reinforcing agent, although there is no direct effect, but indirectly affect the oil resistance, mainly in two aspects, one is to increase the use of carbon black fraction, reducing the volume fraction of rubber in the rubber, can improve the oil resistance of the rubber, on the other hand, filler carbon black are active, and the higher the activity of the vulcanised rubber can be increased in the cross-linking density, to strengthen the bonding force between the rubber molecules, thus increasing the oil resistance The higher activity can increase the cross-linking density of vulcanised rubber, enhance the bonding force between rubber molecules, and thus increase the resistance to oil penetration and swelling ability, thus improving the oil resistance of rubber products. Therefore, from the point of view of oil resistance, the smaller the carbon black particles filled in the rubber, the higher the activity. However, in practical applications, often require oil-resistant hose is also used at the same time in higher temperature conditions, so at the same time require both oil and heat resistance, which should be a comprehensive consideration of the actual conditions of use of the product and the processing technology, often take a hard high wear-resistant carbon black and soft general purpose, fast pressure out of the semi-reinforcement and other methods of carbon black and use. Soft carbon black varieties of processing performance is also better, especially the extrusion hose, such as the use of particles in the middle, the structure of a slightly higher fast extrusion (N550) carbon black is stable product size, smooth surface, is often one of the selected varieties of carbon black.