Rubber seal prevents fluid medium from leaking from device sealed, as well as prevents outside dust, sand and air (relative to vacuum) from entering into device sealed. Such seal is small, but it plays an important role in ensuring performance of various devices and facilities, saving materials and energy and preventing environmental pollution. It is widely used in all kinds of mechanical, instrument, pipe, home appliance, vehicle and other transportation tools, as well as building industry. The rubber materials for rubber seals shall be chosen according to working conditions. For instance, oil resistant sealing products use nitrile rubber; high temperature resistance and anti-corrosion medium seals use hydrogenated butadiene-acrylonitrile rubber, fluororubber, epichlorohydrin rubber, acrylic rubber, and so on.