PE-Xb/EVOH

PEX, in particular the B-type silane PEX in SESTA pipes, is a polyethylene derivative in which certain hydrogen atoms are replaced by chemical groups that bind the polymer macromolecules together in a process called cross-linking. Thus, whereas in polyethylene with increasing temperature the polymer chains can flow with each other and the product becomes deformable, in PEX this flow is not possible and the product remains stable.
EVOH (ethylene vinyl alcohol) is a copolymer that, even in very thin thicknesses, prevents the passage of oxygen and other gases. Coupled with PEX, it does not allow oxygen to enter the pipes and thus prevents sludge from forming and reduces the possibility of corrosion in metal equipment in heating and refrigeration circuits.
The SESTA PE-Xb/EVOH/PE-Xb multilayer pipe consists of 5 layers: PEX inside and outside bonded by two special adhesive layers to an EVOH intermediate layer. This pipe guarantees a high level of mouldability, complete oxygen barrier, total hygiene and absolute corrosion resistance.
The SESTA oxygen barrier hose can also be produced with three layers, respectively PEX, adhesive, EVOH. The characteristics are identical to those of the five-layer hose, however, the outer EVOH layer tends to deteriorate in contact with moisture.