Fiber-based products, in particular paper and cardboard, play an important part in the packaging and printing industries. In addition, their bio-based origin and high recycling rates provide tangible sustainability benefits. Many fiber-based product designs, in particular in the area of packaging, would not be possible without adhesives, which are used in, for example, corrugation, bag and box making, and labelling.
FEICA recently published a paper outlining the place of adhesives in paper recycling. It considers how existing design guidelines for fiber-based products are viewed with regards to adhesives and the treatment of adhesives in test methods and assessment schemes. It also gives recommendations on the way to approach adhesives in paper and fiber-based recycling.
Adhesives in Paper Recycling
Adhesives are generally required to be compatible with the recycling process for the target material, rather than being the target material of the recycling. The two possible pathways that adhesives can take during paper recycling are removal or incorporation into the recycled paper.
If adhesive applications are not (fully) removed before or during papermaking, adhesive fragments may become part of the recycled paper. The key criteria for the acceptability of their presence in the formed paper are the optical appearance of the paper and its potential stickiness. If the formed paper exhibits stickiness, defects in the paper reel or processing issues such as reel breaks, may occur. The impact of adhesive particles in both cases may depend in part on the size of the adhesive application within the packaging item.
Over recent years, several guidelines have been published in Europe that aim to describe design-for-recycling principles for fiber-based products. Different guidelines stress various aspects of recycling involving adhesives. For example, some guidelines recommend the minimization of applied adhesive. Other guidelines prefer solubility of the adhesive in water. Several address the “softness” of adhesives, ultimately with a view to the presence or absence of tack of the adhesive application or adhesive fragments during recycling processes.
The recommendations in these guidelines are often made without consideration of the adhesive technology and application in detail, as, for example, removability is most relevant for hotmelt adhesive applications of a sufficient size, whereas solubility is more relevant for smaller or thinner adhesive applications, such as water-based adhesives. All the approaches may be of use where packaging design and recycling technology match.
FEICA Recommendations
To further develop design guidelines in terms of clarity, applicability and benefit to the quality of paper recycling, while recognizing the importance of adhesives in fiber-based product manufacture, FEICA offers its recommendations in its Guidance Paper.
For more information and to download the paper, visit www.feica.eu.
