HYB-20 material is a three-layer composite self-lubricating material with tetrafluoro-modified polyformaldehyde plastic as its surface layer. It is a kind of benign boundary lubricating material. Therefore, it is especially suitable for high-load and low-speed rotating motion, rocking motion and often opening and closing under load, so it is not easy to form hydrodynamic lubricating bearings, thrust gaskets and sliding. Friction parts such as block, ball seat, etc.