For many years, the adhesives and sealants industry has used a range of standardized test methods to ensure the quality of products for industrial applications. Laboratories generally embrace these as the cornerstone of lab testing. In order to satisfy the requirements of emerging and niche markets, however, non-traditional testing can employ novel test parameters to provide pertinent data.
Distinctive data can help convince customers to allocate time and resources to trial a product in their application. Some recent examples of this inventive testing include the use of a tensiometer to measure the rate of absorption of a hot melt into wax-coated carton stock; rheological characterization to predict the potential of a water-based adhesive to clog nozzles; measurement with a hybrid rheometer to compare the range of a group of hot melts; and loop tack testing for waterborne adhesives.
The evaluation of hot-melt adhesion typically relies on the visual evaluation of fiber-tearing bonds. Little information is usually known about the depth of the bond. A bond that appears to give 100% fiber tear can actually be a very weak bond if the hot melt barely penetrates into the surface. Some of the most difficult bonds to evaluate include those on wax-coated corrugated stock, which are typical in meat or poultry packaging.