This standard test method is used to evaluate the strength of flexible web sealing surface materials during the heat sealing process. It is mainly used to detect the thermal tack of the heat seal area before it is chilled down to room temperature. Encasement is often affected by destructive force during the filling process. If the heat seal strength is insufficient, it may lead to Encasement rupture. This method provides an accurate measurement of heat seal strength through instrumented testing, avoiding the influence of operator technology on the test results. The standard describes two test variants, which differ in the formation of fixture separation rate and chill down Linear dispersion. This test method ensures that the heat seal strength of the material meets the mass requirements in commercial applications.