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Label Improvements Often Depend on Adhesive

Posted on 10/24/2016 11:56:22 AM By Hallie Forcinio
  

The adhesive heavily influences the performance and sustainability of label structures. Chemical formulas and substrate/adhesive compatibility also impact properties such as clarity, moisture resistance, machinability and tolerance to hot and cold temperatures.

Today’s formulas are “greener.” For example, formaldehyde has been eliminated from many pressure-sensitive adhesives, and a growing number of formulas comply with the EU’s REACH (Regulation, Evaluation, Authorization, and Restriction of Chemicals) regulation. Removable adhesives are destined for applications where residue-free removal is desirable, such as informational labels on appliances. Labels with enhanced heat tolerance are specified for electrical and electronic items.

Acrylic formulas on film substrates combine good tack and open time so any misapplied labels can be removed cleanly, and the container can be relabeled with minimal rework. This reduces waste. These pressure-sensitive adhesives resist building up on equipment such as label applicators, presses and diecutters, thereby minimizing downtime associated with cleaning. Many of the resulting label structures are classified as food-grade and are compatible with a variety of inks and printing processes including ultraviolet (UV), solvent and water flexographic, UV and solvent screen, and UV letterpress.

Newer hot-melt labeling adhesives such as H.B. Fuller’s HL-2960 hot melt formula offer similar features as well as aggressive tack, bleed resistance and a broader application temperature window.

To enhance sustainability, greener adhesive formulas, which offer lower levels of volatile organic compounds and toxic chemicals, are combined with downgauged label substrates. Ultra-thin facestock cuts costs and conserves resources.

Recyclability is another major consideration. Since adhesives and label materials can contaminate the polyethylene terephthalate (PET) recycling stream, products such as Avery Dennison’s CleanFlake label portfolio and UPM Raflactac’s polypropylene label stocks with its RW85C wash-off adhesive are structured for residue-free separation during the washing process. The resulting PET flake is cleaner and can be turned into new food-grade containers.[KDG3] [HF4]  Container-to-container recycling minimizes downcycling of post-consumer PET into carpet fibers or pallet strapping, landfill waste and consumption of virgin PET. 

These recycling-friendly labels have passed testing guidelines set by the Association of Postconsumer Plastics Recyclers (APR). Any label destined for a PET container should be tested to ensure the ink, substrate and adhesive combination do not result in contaminated, low-quality flake. APR provides extensive resources to help brand owners specify and test recycling-friendly packaging. Downloadable content may be accessed via The APR Design Guide for Plastics Recyclability on the APR website[KDG5] [HF6] . Other materials may be found on www.adhesives.org.