Tear resistance

Tear resistance is a film's ability to resist the start and spread of a tear. It keeps pouches intact through handling and shipping, yet packaging often also needs controlled tearing so consumers can open it easily.

Initiation vs. propagation

Most plastic films resist tear initiation well, which is why packs have a tear notch. Propagation resistance, the force needed to continue a tear, is measured with methods such as Elmendorf tear testing.

Direction matters

Films are stretched during manufacture, so tear behaviour differs between machine direction and transverse direction. Oriented films like BOPP and PET tear easily once notched, while PE is tougher and stretchier. Design the opening direction with this in mind.

Where it matters

• Heavy packs, where a small nick must not grow into a split
• Easy-open snacks and coffee, using notches, laser scoring or straight-tear films
• Sharp products, alongside puncture resistance

Tell your converter if you need both strength and easy opening; notch position, tear direction and layer choice can balance the two. Drop and transport tests give the most realistic answer for heavy fills.