Is there a standard method available for the validation of the effectiveness of an heat seal, e.g. permeability, long term effectiveness?

Jim Lambert

Jim,

At the bottom of the homepage of the website of our industrial partner Hawo: www.hawo.com/homepage_E.htm you can find the information you're looking for by clicking on: More about validation of heat sealing equipment.

Good luck,
Wim Renders

There are a few tests that are used for validating the performance of the seal machine.

1. The dye migration test is used to determine the integrity of the package seal. This test involves injecting dye into the package and placing the weight of the solution against the seal for a specific length of time. The package is examined for evidence of seal failure demonstrated by dye slipping through the seal.
2. Bubble emission test involves inflating the package and submerging it into a surfactant solution for a specific length of time. The package is examined for evidence of seal failure demonstrated by bubbles emerging through the seal.
3. Seal peel tensile test determines the strength of the seal at a specific place on the package. This can be helpful in setting the sealing parameters. This test involves measuring a one inch segment of the package along one of the heat seals and cutting the package so that there is at least four inches of material on each side of the heat seal. This sample is then inserted into the grips of a tensile test instrument with the heat seal centered between the two grips and the instrument initiated. The results are reported as load at yield and energy to break.

Creating a QA system for the sealing process should take into consideration

1. The volume of production.
2. Type (s) of machine.
3. Available resources for validation.

Routine daily inspection of the machine displayed temperature, printer etc. is recommended. For above mentioned tests a periodical sample of packages should be taken for one or more of tests. The sample size should be sufficient enough to represent the overall production volume.
The dye migration test is the easiest test available. I have seen it done in China, using domestic devices, like laundry lines and clips, for hanging the pouches with dye.

Yaffa Raz