The Heat is On

“That’s not an easy change,” he reports. “Just a few percentage points of stretch during the converting process can destroy the barrier properties of coated PET, so it takes a great deal of finesse and excellent machinery to create a good microwaveable retort pouch.”

The inks and adhesives used in retort pouch applications also have to be carefully selected. “The majority of retort pouches are rotogravure printed,” notes Weaver. “Specially designed inks and adhesives are required for retort applications, primarily because of the high temperatures and pressures of processing.”