Recycling Compatible Adhesives

The push, performance and price

‍Mike Witte, manager, Pressure Sensitive Adhesives Business, Franklin Adhesives & Polymers, Columbus, OH, USA, discusses his recycling compatible adhesives (RCA) observations. "We are seeing more and more inquiries for adhesive products that have any kind of green attributes, and that certainly includes recycling compatibility. Historically, end users have not been willing to pay a premium for such attributes, which slowed entry of these products into the marketplace. I think this is changing as awareness grows and the ability to differentiate products by virtue of environmental friendliness gives label producers competitive advantages. I think the next steps will be to develop and promote sustainable materials for both face and adhesives; and that biodegradability will become the next target for both," he says.

Franklin Adhesives & Polymers has gained RCA certification in part as a result of the division's joint research project with the University of Minnesota, which was funded by the US Department of Energy, to reduce or eliminate residual adhesive from waste paper during recycling. "Residual adhesive adheres to papermaking equipment during the manufacture of paper from recycling paper, leading to machine down time and specs or tears in the final paper products. We focus on developing green adhesives and the university research team wanted to test our pressure sensitive adhesives for recycling compatibility. They found that three of the formulas we provided them are easily removed from paper during re-pulping," Witte says.

Franklin offers two FPL-certified recycling compatible adhesives" Covinax 324-39 and Covinax 379-05. "Covinax 324-39 is a vinyl acrylic co-polymer for general-purpose permanent pressure sensitive adhesives on tapes and labels. It is used for corrugated substrates, polyolefin films, glass and metals and is easily converted into rolls or sheets without sticky edge problems. These formulas can be transfer-coated on most rod, gravure or roll coaters.

"FPL-certified Covinax 379-05 is an acrylic adhesive for permanent pressure sensitive applications, including pharmaceutical label applications requiring adhesion to curved or irregularly shaped surfaces. The balance between peel and shear strength also renders this formulas easily convertible to rolls or sheets. It is specifically designed to be transfer-coated on slot die coaters and can be used on most rod or roll coaters, "Witte says, adding, "In our case, the products that are recycling compatible are very cost effective; no development costs were incurred to achieve recycling compatibility."