Workhorse With the Goods
Adhesives are not the most elaborate or stimulating element of packaging construction, but their role is essential to overall packaging success.
July 2006 by Kate Sharon
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Adhesives are by no means a component of packaging selected on a whim. The sticky substances are an integral element in packaging projects, and differ depending on a variety of factors that are important to the structural integrity of the packaging and, ultimately, to a consumer’s experience with a product.
Even still, adhesives aren’t exactly big headline newsmakers and they beg the question, “What’s new?” According suppliers of adhesive materials, that’s a question with good answers.
The last five years have seen innovations in the raw material components that constitute adhesives. The result of these advancements has been the development of adhesives with refined and enhanced capabilities.
Better raw materials
Aqueous, ultraviolet (UV), and electron beam (EB) are three types of adhesives and all have seen improvements due to raw material developments.
Water-based adhesives have always been the safe, non-toxic, environmentally-friendly choice. However, they have always been limited in the applications for which they were suitable. Today, new raw material alternatives have changed that.
“There has been a definite improvement in adhesives, specifically in the aqueous area,” said André DiMino, president and CEO, ADM Tronics. “This is due to a wider choice of raw material stocks over the past five years, which can now be incorporated into aqueous adhesive formulations. This has given us the ability to produce aqueous adhesives for applications which previously were only satisfied by hazardous solvent-based adhesives. Performance and application enhancements have expanded these newly available raw material choices.”
In the realm of energy-curable adhesives, UV and EB, advances have also taken place in their chemistries. In the last decade, the use of UV adhesives, inks, and coatings has become prominent. What has spurred this increased utilization is partly due to the advancements made in UV curing equipment and its growing affordability, and partly due to the improved raw material compositions of UV-cured substances.
“UV adhesives have improved dramatically in the last five years as many manufacturers of UV raw materials have developed products specifically for these applications,” said Todd Dickenscheidt, Research & Development, UVitec Printing Ink. “Also, free radical cure mechanisms are being used frequently now, where before almost all UV adhesives used cationic cure mechanisms.”
According to Dickenscheidt, this is important for two main reasons: time and application. “Cationic formulations were originally used almost exclusively because they tend to give a slower cure so that your adhesive will start very tacky and then harden after setting for a period of time. Free radical mechanisms always cure in about half a second to a given degree of tackiness. The primary advantage of free radicals is that the process has more leeway since the adhesive will stay at a certain level of tackiness after curing, allowing you to apply your label, etc., at any time,” he said. “Cationic adhesives must be applied and allowed to set at very precise dwell times. Also the cationic process is affected by humidity, so that dwell times will change as the humidity goes up or down. Cationic adhesives are still useful for applications requiring a stronger bond between substrates, however, the adhesive will dry to a very hard film instead of remaining soft like the free radical adhesives. The selection of mechanisms is based on end-product requirements, as well as ease of processing and humidity control.”
Even still, adhesives aren’t exactly big headline newsmakers and they beg the question, “What’s new?” According suppliers of adhesive materials, that’s a question with good answers.
The last five years have seen innovations in the raw material components that constitute adhesives. The result of these advancements has been the development of adhesives with refined and enhanced capabilities.
Better raw materials
Aqueous, ultraviolet (UV), and electron beam (EB) are three types of adhesives and all have seen improvements due to raw material developments.
Water-based adhesives have always been the safe, non-toxic, environmentally-friendly choice. However, they have always been limited in the applications for which they were suitable. Today, new raw material alternatives have changed that.
“There has been a definite improvement in adhesives, specifically in the aqueous area,” said André DiMino, president and CEO, ADM Tronics. “This is due to a wider choice of raw material stocks over the past five years, which can now be incorporated into aqueous adhesive formulations. This has given us the ability to produce aqueous adhesives for applications which previously were only satisfied by hazardous solvent-based adhesives. Performance and application enhancements have expanded these newly available raw material choices.”
In the realm of energy-curable adhesives, UV and EB, advances have also taken place in their chemistries. In the last decade, the use of UV adhesives, inks, and coatings has become prominent. What has spurred this increased utilization is partly due to the advancements made in UV curing equipment and its growing affordability, and partly due to the improved raw material compositions of UV-cured substances.
“UV adhesives have improved dramatically in the last five years as many manufacturers of UV raw materials have developed products specifically for these applications,” said Todd Dickenscheidt, Research & Development, UVitec Printing Ink. “Also, free radical cure mechanisms are being used frequently now, where before almost all UV adhesives used cationic cure mechanisms.”
According to Dickenscheidt, this is important for two main reasons: time and application. “Cationic formulations were originally used almost exclusively because they tend to give a slower cure so that your adhesive will start very tacky and then harden after setting for a period of time. Free radical mechanisms always cure in about half a second to a given degree of tackiness. The primary advantage of free radicals is that the process has more leeway since the adhesive will stay at a certain level of tackiness after curing, allowing you to apply your label, etc., at any time,” he said. “Cationic adhesives must be applied and allowed to set at very precise dwell times. Also the cationic process is affected by humidity, so that dwell times will change as the humidity goes up or down. Cationic adhesives are still useful for applications requiring a stronger bond between substrates, however, the adhesive will dry to a very hard film instead of remaining soft like the free radical adhesives. The selection of mechanisms is based on end-product requirements, as well as ease of processing and humidity control.”
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