Slow Rate Penetration of Packaging Films

A detailed evaluation of the slow rate penetration resistance measure ment was conducted on twenty-two different monolithic, coextruded, or laminated flexible barrier packaging films using five different probe geometries. No universal change in penetration resistance with penetration rate was found. Decreasing probe sharpness or severity increased the observed penetration resis tance and improved the signal-to-noise ratio. However, similar rankings of film per formance were possible regardless of probe geometry. After considering these and many other factors, it is recommended that measurement of slow rate penetration re sistance should be made using a 20 mm/min penetration rate and a 3 2 mm dia hemispherical probe with a probe:clamp diameter ratio of 10.