It has obvious advantages in reducing the noise generated during operation and improving the bearing life. The so-called coated bearing, that is, the outer ring of the bearing is coated with a layer of glue, hard glue and soft glue, the current coated material is polyurethane (PU), polyformaldehyde (POM) and polyacrylate (PA), among which the application of polyurethane (PU) is the most popular, is the most popular material in the coated bearing. It has oil resistance, impact resistance, low temperature resistance, ozone resistance, radiation resistance, high load capacity and thermal insulation performance. Widely used in precision instrument industry, transmission equipment, doors and Windows, hardware pulley and other fields.