New Resin Makes Peelable Seals for Retortable Polypropylene Packages
“The new Appeel grade gives converters an easy way to tailor peel force and achieve consistent sealing and peeling performance with a preformulated masterbatch,” says Terry Kendig, senior technical development specialist of DuPont Packaging & Industrial Polymers.
Appeel 22D843 is typically blended with PP at addition rates of 20 to 40 percent by weight. The proportion of Appeel in the blend determines peel strength. Lower addition rates result in higher peel force and vice versa.
Either homopolymer or copolymer PPs can be used. The choice of PP depends on the melt index requirements of the extrusion process and performance needs. Copolymer blends have a lower seal initiation temperature while homopolymer blends may withstand higher retort temperatures. Appeel 22D843 is a PP-modified ethylene acrylate resin.
Blends of PP and the new Appeel grade can withstand sterilization conditions from 121°C for 20 minutes up to 134°C for 6 minutes with adequate counter pressure, depending on the type of PP employed.
DuPont Packaging & Industrial Polymers