Adhesives for Minimalist Packaging

Posted on 5/7/2019 5:18:48 PM By George Ritter

In the 1990’s, as a senior chemist and laboratory director, I managed about twenty R&D scientists who supported our then-portfolio of hotmelt and waterborne adhesives for food packaging applications, including flexible packaging. My wheelhouse later expanded to ultrasonic welding and hybrid systems for the U.S. Department of Defense’s Meal, Ready-to-Eat (MRE) packaging.

Two interesting features of that hybrid system included:
 - ultrasonic technology could be used to heat the hot-melt adhesive; 
 - food particles were more effectively driven out of the joint.


That said, apart from snack food packaging and possibly meat packaging, ultrasonic welding can’t be substituted for adhesives, due to some inherent limitations in applicability. As a rule, dissimilar plastics can’t be welded, for example, which means packaging adhesives will still be necessary for many laminated structures.

In a recent article published for the Adhesives and Sealants Industry, I discussed the importance of packaging, which has enabled the distribution of food, water, and medicines in safe, reliable containers for centuries. Packaging is undeniably essential to the world’s health and well-being.

packaging photo_cropped

Like many things in life, however, packaging can become too much of a good thing: The shelf life may be brief (weeks) and the consumer’s use may end in less than an hour after the package and its contents are sold. Of the fast-moving consumer goods (FMCG) packaging category, a significant portion is single-use. End-of-life disposal is a volume issue and recycling is difficult at times, especially when the packaging has advanced structures featuring many layers of materials, each with a different but necessary purpose.

For these reasons, I am exhorting the packaging community toward a noble quest: continue to strive toward minimalist packaging design with an eye toward adhesives and materials combined into more recyclable structures.

Meanwhile, there are ways that packaging materials can be combined efficiently with a lower load on the downstream waste cycle. One method is to combine the structural film elements more efficiently using films that can be combined more readily with lower volumes of higher performing or multifunctional adhesives. And if that is to happen, how can companies run small scale test combinations using modern technologies that they may not currently be processing in their standard manufacturing facilities?

Recently, ChemQuest integrated forward into a large, modern laboratory space located in South Boston, Virginia. The ChemQuest Technology Institute (CQTI) has two major technical thrusts: 

- The facility provides a third-party neutral space for working with formulations of new adhesives, resins, and coatings;

- CQTI enables third party, neutral evaluation of potential new resin chemistries through, for example, custom synthesis, formulating, and molecular and polymer analysis. 

Chemistries and performance testing are only part of the picture for envisioning new resins systems. Processing is also key. This is where CQTI offers the unique ability to move into pilot scale process evaluation. 

So, this unique process facility enables large-scale testing of modern processing for new or existing resin systems applied by multiple available processes and cured with multiple available means, including some of the latest techniques in industry. For example: It could be possible to spray coat adhesive as a pattern onto a film, dry (if needed), laminate and cure by UV. Another option would be to apply, crosslink with heat, and then laminate. All of this work can be confidential and highly customizable to your end goals. 

If we want to stimulate more recycling and repurposing, what are the challenges facing adhesive technologies? The overall goal is to “do good, not do less bad.” This means that beyond good overall performance, new laminating and sealing adhesives must be compostable. Conversely, an adhesive may need to last longer if the package is designed to be reused, refilled and re-sterilized, or repurposed. Obviously, these are two ends of a longevity spectrum.

When I first worked in laminating adhesives, waterborne adhesives were scarce, and urethanes were virtually unknown. Most laminating was done with solvent-borne adhesives and most of those solvents were both flammable and potentially toxic. The solvents were flashed and burned. Now we are in an era of 100%-solids adhesives, crosslinkable adhesives, and systems tuned to minimize environmental impact. Packaging has come a long way in seeking to maximize performance and reduce environmental side effects. Part of that can be credited to the use of modern and innovative processing to join structures with efficient use of adhesives. Albeit there is much more work to be done in the packaging value chain to ensure a healthy planet for future generations, and adhesives technology has a central role to play.

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