Expanded polyethylene or EPE is non-crosslinked, closed-cell polyethylene foam made from low-density polyethylene (LDPE) resins. EPE foam has good thermal insulation properties and is also waterproof, thus it has large number of packaging applications.
It is manufactured using an extrusion process and is normally available in several forms i.e. sheets, rolls, pipes, rods, L sections, C sections and U sections with each have its own set of uses. It is most widely used in form of sheets and rolls.
References
Expanded polyethylene Wikipedia(Text) CC BY-SA