Case Study: Evaluation of hot melt adhesive performance on corrugate substrates

When faced with a choice of new hot melt adhesives for a corrugated fiberboard box application, a component manufacturer turned to Smithers Pira to help with their decision.

The Challenge

A component manufacturer was faced with a decision of new hot melt adhesives to choose for a corrugated fiberboard box application. Of course, the natural comparison of cost vs. performance came into play and the client had to ensure that performance would not degrade if they chose the lower cost option. Unfortunately, there was not a specific standard or test method that would give the answer. The experts at Smithers Pira worked in conjunction with the development team to find the best performance assessment method.

Thermoplastic hot melt adhesives are commonly used for corrugated packaging closures because of their excellent adhesion, quick set and relatively low cost.  This makes them ideal for the automated high production, high speed lines used for packaging applications.

Determining which hot melt adhesive to use for a particular application can be challenging because there are currently no standardized preparation or testing methods to determine the performance of hot melt adhesives on a particular corrugate substrate prior to pilot or productions runs. After researching the issue, Smithers Pira experts were able to develop a custom test method that utilized pieces of the TAPPI (Technical Association of the Pulp and Paper Industry) T813 standard to evaluate the performance of the hot melt adhesives in question.

The Evaluation

Single lap shear samples were fabricated in the lab utilizing two different hot melt adhesive types, Type A and Type B, on a C-flute corrugate substrate.  The two hot melt adhesives were then processed at two different temperatures (375° F and 500° F) before application onto the cardboard samples. After adhesion, the samples were conditioned in a temperature and humidity controlled chamber at three different temperatures. Finally, after conditioning, the samples were tested on a tensile tester to understand when the adhesive bond would fail with the substrate.

The Conclusion

It was found that the replacement, less expensive hot melt material actually performed better than the original hot melt in every tested condition. In addition to exhibiting better performance characteristics, Type B’s cost was 58% lower than Type A providing a large cost savings opportunity for the manufacturer.

In summary, from project initiation to receiving the final report, the manufacturer was able to work with Smithers Pira experts to apply science to their issue in just 20 days allowing for a fact based cost savings decision.  The savings gained in the exercise far outweighed the cost of testing.

Interested in how your next challenge can be resolved through science based test development? Want to test your potential packaging cost savings against the cost of technical validation? Visit Smithers Pira today to get started on your next project.

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Addendum: In the month's following the release of this article, the team at our UK distribution testing facility launched the PAPT 3 machine which permits our lab to conduct controlled testing to measure the open and setting time of hot melt adhesives. Read more about it here:

PAPT 3 Testing >