PEVA / EVA Ethylene Vinyl Acetate
EVA and PEVA are the same thing. EVA is short for ” ethylene vinyl acetate “. Somehow “polyethylene” got added as a prefix to create the acronym PEVA. Both are words for the same copolymer. PEVA / EVA is a copolymer comprised of the monomers Ethylene C2H4 and Vinyl Acetate Monomer CH2=CHOOCCH3 conjoined to make the copolymer Ethylene Vinyl Acetate, or EVA for short.
Terms such as PEVA and EVA are used loosely. The result is confusion for the consumer. Here is an example:
Vinyl Acetate monomer cannot be mechanically mixed at the extruder. It is made at specific percentages by the resin companies.
EVA is used for many applications besides film. This discussion is only about EVA as it pertains to blown film.
EVA lowers the seal initiation temperature and melting point of PE film. In low percentages, it has been used for decades for enhanced sealability for bread bags (2% EVA ), ice bags (4% EVA) and frozen food packaging (usually 6% EVA). In higher percentages, more or less 20% EVA, it is used for low melt/total batch inclusion bags. It is a common practice to say the ostensible percent of EVA is one not made by a resin company. It is a common sabotage spec.
The higher percentage EVA, the lower the melting point whether measured as DSC melting point or vicat softening point.
Higher percentage EVA’s are soft and tacky. Solar panels require a bonding layer. The resin of choice has emerged as 33% EVA. It is too sticky to make into film. It must be made by the case process.
EVA has a pungent, apple vinegar odor which can transfer to foods especially dairy products.
While EVA is considered obsolete by many for packaging applications because metallocene offers faster hot tack, demand for EVA remains strong for PVC replacement.
For more in-depth discussion of EVA and PEVA, visit our blog posts :
or watch this video to learn history of EVA and why EVA is obsolete in some respects.
