Packaging Materials And Viscosity

By Robert G. McGregor, Sales Marketing Manager, Brookfield Engineering Laboratories, Inc.

What does packaging have to do with viscosity? Quality Managers worry about their food products and measure viscosity to ensure proper flow behav­ior, such as with sauces and dressings. But why concern yourself with the containers these products go into or the shipping boxes? Very simply, the adhesives, inks and coatings used for these packaging materials also require viscosity measurement and control to provide durablaettract­ ive products that will serve the food manufacturer well.

The viscosity issue is the same for all. Be it an ink or an adhesive, the consistency of the material is ensured by measuring its viscosity. A rotational benchtop viscometer is the tool of choice and provides a quick pass/fail indicator once the measurement is made. Normally a specification already exists defining the spindle, rotational speed, time of rotation, operating temperature and sample volume. If there is no spec, then one is created, based either on supplier information or from a char­ acterization test run on the ink/adhesive.

For some adhesive materials, such as hot melts, the viscosity measurement is made at elevated tern perature. The Thermosel System provides the rapid heating capability to test small sample sizes quickly and efficiently for viscosity.