What kind of pipe is PPR insulation pipe

PPR insulation pipe is composed of high-density polyethylene outer protective layer, polyurethane rigid foam and PPR pipe. The rigid polyurethane foam of the PPR insulation tube fully fills the gap between the PP-R tube and the high-density polyethylene outer protective layer tube, and has a certain bonding strength, so that the PP-R tube and the high-density polyethylene outer protective layer A solid whole is formed between the pipe and the polyurethane insulation layer