Meaning
Polyamide films undergo mechanical stretching in two perpendicular directions to create a high strength barrier material with superior puncture resistance. Producing biaxially oriented polyamide involves heating a cast nylon sheet and pulling it to orient the polymer chains. This process increases crystalline structure and transparency.
Barrier Property
Gas transmission rates drop sharply compared to unoriented cast films when biaxially oriented polyamide is utilized. This film resists oxygen permeation and aroma loss, which protects food quality in vacuum packaging applications. High humidity levels can occasionally affect the barrier performance of the nylon base.
Flexural Strength
Durability during shipping is a primary advantage of this material. Because biaxially oriented polyamide resists pinhole formation under repeated folding, it is a preferred choice for liquids or sharp edged products. The orientation process ensures that the film does not tear easily during high speed converting or filling operations.
Shrinkage Tension
Thermal stability during secondary processing like lamination or printing remains a critical variable. Because biaxially oriented polyamide can shrink when exposed to high heat, tension control on the press must be precise. Pre-treatment or annealing steps are often applied to minimize dimensional changes during steam sterilization, ensuring the final package maintains its shape and seal integrity under stress.
