Product/package interactions were evaluated for three product/package systems: a bleach alternative laundry additive, an anti-bacterial surface cleaner, and a glass surface cleaner. The package system was comprised of high-density polyethylene bottles with induction-sealed closures. The physical environment was studied by comparing product/package systems that were exposed to simulated distribution testing with those that were not. The storage environments were ambient conditions at 73°F (23°C), and higher temperatures at 100, 120, and 140°F (38, 49, and 60°C).
Damage caused by distribution testing occurred in the bottle or in the closure component of the package. Bottle defects resulting from distribution testing were dents, abrasions, and creases. Closure defects included sheared-off closures, cracks in the closure body, or nozzle cover damage.
Product/package systems exposed to the four storage environments were inspected for failure, defined as product leaking from the package, during the six-month study. Failures were due to environmental stress cracking. Dents in the shoulder and bottom region of the bottle were the only simulated distribution defects that impacted the storage stability of the product/package systems, which often resulted in reduced shelf life. The primary location of all other failures was near the center of the bottle bottom edge, which was the thinnest region of the bottle. Bleach alternative laundry additive was the most aggressive product, while the two surface cleaners exhibited similar storage stability.
Performance criteria of the failed bottles were evaluated to study the impact of package system properties on product/package integrity. Yield strength, modulus of elasticity, and dynamic mechanical properties of failed sample-acquired bottle side panels did not change significantly from those of the control samples. Color changes were monitored by measuring interior and exterior surface yellowness indices of bottle side panels. Although observed spectrophotometrically, these changes were not detected visually.