Inks, Coatings, and Adhesives

Studied the sustainability considerations relevant to inks, coatings, and adhesives used in packaging.

Completed

Team Objectives:

  • Create an informational resource that provides high level information about various inks, coatings, and adhesives used in packaging
  • Add Inks, coatings, and adhesives to more of the discussions about sustainable packaging
  • Recognize a  defined Collaborative within the SPC that can serve as a resource to address questions and concerns about inks, coatings, and adhesives.

Inks, coatings, and adhesives can play a major role in enhancing or disrupting the sustainability attributes of packaging. This group seeks to broaden the conversation about sustainable packaging to include these important components. As a first phase, the Collaborative has limited its focus to applications on Rigid Polyethylene Terephthalate (PET Bottle), Oriented Polypropylene (OPP Flexible Film), and Solid Bleached Sulphate (carton) substrates.

Key Findings:

All ink, coating, and adhesive applications must be assessed on an individual basis. Formulations and applications vary widely and are continually evolving in order to meet regulatory requirements and product design changes.  Various innovations are also being driven by changes in equipment, leading to improved efficiencies while maintaining and balancing existing specifications.  Therefore, discussions at a high level do not consider specific variables that may influence business decisions.

Concerns with inks, coatings, and adhesives tend to be around recyclability (ease of removal, potential spotting, pigment and other contaminants, etc.); human and environmental health impacts throughout manufacturing, application, and use; and ensuring that these formulations help to successfully deliver products with adequate protection and information. The application  method, chemical composition, application conditions – including specific combination of formulations applied, and substrate composition can all have significant impacts on ease of removal in recycling and reuse.  Application thickness has a significant impact on recyclability. In general, a thicker application is more problematic than lighter applications, but this is not the case in all instances. Factors influencing application methods and formulation types include equipment availability, environmental restrictions, regulatory practices, product categories, expected typical run length or variability in design, and other economic considerations (capital expense, formulation expense, etc.).

The work of this Collaborative is intended to advance the discussion of sustainable packaging to include considerations for inks, coatings, and adhesives as opposed to providing information that drives purchasing decisions.

Inks: Many inks are comprised of four components colorants, vehicles, solvents,  and additives .  In the recycling process,  some inks can bleed or dissolve during agitation in hot water, which can discolor collected material. This could be related to properties of the colorant selected, or it may be due to the ink vehicle selected.  This type of contamination may also vary by the equipment available at the recycling facility and specific recycling conditions utilized, such as variations in deinking equipment if applied.

Coatings: In some regards, coatings could be generalized as inks without colorants or as inks with non-pigmented fillers in other instances.  The vehicle percentage is typically greater in coatings and the additives selected can serve a different purpose, but in a high level discussion, coatings can be thought to comprise of non-pigmented fillers, a vehicle, and additives.  While coatings are used to protect the aesthetics, branding, and messaging of a product, some formulations’ bonds result in material losses if effectively removed in the recycling process, or can become contaminants (spotting or discoloration) if not removed.  Variability in application thickness and application conditions along with physical properties of the individually formulated coatings can significantly impact end of life impacts for all formulations.

Adhesives: Packaging accounts for one of the largest markets for adhesives. Label adhesives  should be water soluble or dispersible at temperatures between 140 °F to 180 °F in order to be  removed in conventional washing and separation systems used to process recovered polymers.  If not removed, they may become contaminants and/or cause discoloration. Adhesives with densities similar to water are difficult to remove, particularly when processing recovered paper products.

About the group

The Collaborative on Inks, Coatings, and Adhesives is a group of SPC member companies (listed below) that have come together under a topic of interest. Group participants contributed to the development of this resource through monthly conference calls, collaborative resource development, and by being an initial review panel.

Eric DesRoberts: GreenBlue

Frank Clementi: Cork Industries

Anna Low: OIA Global Logistics – Creative Packaging Solutions

Mike Sajdak: INX International Ink Co.

Chuck Williams: Avery Dennison

Ken Wolfe: Avery Dennison

Mark Jones: Danimer Scientific LLC

Jim McWilliams: Cork Industries

Sridevi Narayan-Sarathy: PepsiCo

Weilong Chiang: PepsiCo

Ken Alston: MBDC

Gary Robinson: Billerudkorsnas

Thomas Fu: LBP Manufacturing

Ian Bucklow: Crown Holdings