Ionomers (polymers that can form cross-links between chains due to ionized functional groups) are often used for vacuum-packaged products because they have the strength needed to resist puncture and tearing when vacuum is applied. Due to material shortages for ionomer materials, processors have sought lower-cost alternatives to ionomers for food packaging.
A collaboration between ExxonMobil (Spring, Tex.; www.exxonmobil.com), Kuraray (Tokyo, Japan; www.kuraray.com), GAP s.r.l (Trecate, Italy; www.gapitaly.com) and G. Mondini S.p.A. (Cologne, Italy; www.gmondini.com) has resulted in development of a polyethylene-based polymer that exhibits properties similar to the ionomer-based packaging, but saves raw-material costs by eliminating the need for ionomers.
Source: ExxonMobil
The packaging product layers ExxonMobil’s Exceed Flow+ m0516 and Exceed Tough+ m0512 performance polyethylene products with Kuraray’s ethylene vinyl alcohol (EVOH) polymer for oxygen barrier and ExxonMobil’s ethylene-vinyl acetate (EVA) resin for stress-crack resistance and low-temperature toughness. Films of this layered polymer were made by GAP, and G. Mondini incorporated it into its vacuum-pack machines for use.
According to an ExxonMobil case study, the ionomer-free packaging film maintains critical performance characteristics for toughness, seal integrity, tear resistance and optical properties, while also achieving goals for cost-effectiveness.