The type of resin in the filter paper depends on the working occasion of the filter paper,  is generally divided into two basic types: thermosetting  non-thermosetting (non-thermosetting includes low-temperature curing  non-curing). It can increase the strength of the filter paper,  can be folded into corrugations to make a filter element. The molecules of thermosetting resins form a three-dimensional structure at the curing temperature. This type of resin is widely used due to its good adhesion  aging resistance, among which phenolic resin is commonly used. Non-thermosetting resin (linear structure type) only needs a little heat  no heating during processing,  is usually used under less severe conditions, such as car air filter paper. Most of these resins are polyvinyl acetate resins  acrylic resins.