Predicting the Strongest Peelable Seal for ‘Easy-Open’ Packaging Applications

The effect of heat sealing temperature, time, and pressure on the heat sealing strength of five commercially available packaging films has been evaluated in order to obtain the strongest peelable seal for ‘easy-open’ packaging applications. The mechanical and physical properties of the seal are evaluated. An innovative method and technique to measure the heat sealing properties of different packaging materials is outlined. Inflection points on the temperature-time sealing profile were obtained and determined to be equivalent to the fusion temperature. The fusion temperatures correlated well with the highest peel strength of seals made at the experimentally determined temperatures. The highest peel seal strength has been achieved at a temperature near the fusion point, but below the melting point. The seals made above the fusion point result in weld seals. The pressure has limited effect on the sealing properties of the sealed films in the range tested for this work. The method has been found to be applicable to design of peelable heat seals for many packaging materials and seems to have promise as a method of process measurement and validation for heat seal processes. The project foresees the potential use of this method into other widely used packaging materials, and the method can be useful in the Hazard Analysis and Critical Control Point (HACCP) system for heat sealing processes.