Package Strength

Package strength concerns the force required to separate two components of the package. Package strength testing generally refers to the package seal quality, such as the force required to separate two flexible components of a pouch, the force to separate a flexible lid and a thermoform tray or the compressive force exerted by an elastomeric closure onto a parenteral vial finish after capping. These forces may be measured in pounds per inch of width, as in the seal/peel test per ASTM F88, or in pounds per square inch, as in package burst testing methods. These tests of package strength serve to characterize and monitor package seal quality.

With a consultative approach, we offer a wide variety of testing options for package strength testing:

Burst Testing

We internally pressurize a test package and apply increased pressure until the package seal(s) bursts. The package burst strength test result (reported in pressure units) provides an indication of relative seal strength and evaluates the most likely location and mode of package failure when the package is exposed to a pressure differential. Pressure differentials leading to seal failure may occur during the sterilization processes and transportation (such as low pressure/high altitude exposure). We perform package burst tests in accordance with ASTM F2054 or ASTM F1140, with or without restraining plate fixtures.

Package Seal Strength Testing

Package seal strength testing measures the force required to peel apart two bonded materials. It applies to testing seals between two bonded, flexible materials, such as a pouch or between a flexible material and a rigid material (in the case of a Tyvek-lidded tray). The average force results indicate the seal strength between the bonded materials. The results are useful for monitoring the consistency of the sealing process over time per ASTM F88.

Leakage and Torque Testing

We test closure application torque to designate an optimum application range to prevent leakage from loose closures and component distortion or compromised seals from closure that may have been over-torqued. Application torque degrades over time due to stress relaxation and some closure “back off” that may occur as a function of time and other environmental variables. A properly designed and applied closure will retain sufficient sealing force until the package is opened. Closures that back off excessively during shipping, storage or distribution increase the risk of product leakage and may not meet CPSC standards. Vacuum leakage testing (ASTM D4991) and altitude simulation (ASTM D6653) can assist in the development process. Torque degradation studies (ASTM D2063) can help you assess how much closure retention torque may be lost after exposure to temperature cycling, compression and vibration.

Residual Seal Force Testing

We offer in-house parenteral vial capping and residual seal force testing of parenteral package systems, which are often performed in conjunction with helium leak testing or vacuum decay leak testing.

Airborne Ultrasound

We perform this nondestructive test check to assess seal quality, identifying the presence and location of seal defects such as incomplete seals, channels, wrinkles, seal contaminants or weak bonds.