key performance requirements for flexible packaging

•Sealability: to allow packages to be made at high packaging speeds and keep the product secure by preventing the package seams from failing. Sealability may be characterized by heat-seal and hot tack strength, heat-seal and hot tack initiation temperatures, seal-throughcontamination performance, caulkability, and seal integrity. Hot tack refers to the seal strength while still in the molten state. It is critically important for packages where the product drops into the package while the seal is still partly molten, but also for horizontally filled packages involving gussets where the spring-back nature of the folded film creates an opening force. Caulkability refers to the ability of the sealant material to flow, filling in gaps around folds, wrinkles, or product contaminants. 

• Machinability: to allow the packaging films to be easily run on high-speed automatic packaging equipment. Machineability is governed largely by film modulus, film thickness, seal properties, and coefficient of friction. 

• Consumer appeal: package appearance is an important factor driving product preference by consumers. Appeal is largely related to print quality and package gloss. Film thickness and modulus may also impact consumer appeal.