Seal Strength

Seal Strength of medical packages is measured using a strain gauge test instrument such as an Instron® testing system or Chatillon®  gauge or testing instrument. One-inch wide samples are cut perpendicular to the seal and pulled apart at a constant speed (usually 12 inches/minute) when mounted in the grippers of the instrument. The force required to separate the two sealed substrates is measured and reported as x lbs/inch width. Various configurations are used depending on the application, e.g., unsupported or supported tail, and the tail can be supported at 90 or 180 degrees. Seals of medical packages are critical to sterility maintenance. Seals must remain intact, providing a hermetic seal until the package is opened. In the case of peelable seals, there is a practical maximum as well as minimum seal strength. Depending on the package size, package shape, package style, package contents, content weight, sterilization method, opening method and distribution criteria, a peelable package seal strength may vary from 0.5 lbs/inch width to ~4 lbs/inch width.

Seal Strength - unsupported tail

Non-peelable packages may have a destruct seal which may not peel at all. Seal strength may measure up to the tensile strength of the weaker of the two substrates involved.

ASTM F88/F88m-09 Standard Method for Seal Strength of Flexible Barrier Material