The growing use of shrink and stretch sleeve labels on plastic bottles is a dual-edged sword for PET recyclers.
“The labels are a mixed blessing for PET reclaimers,” said Dave Cornell, technical director of the Association of Postconsumer Plastic Recyclers. “[They] are free of adhesive ... but new problems are created such as proper identification of the bottle resin, removal of the label from the bottle” and the clumping of the label material at recyclers.
Those challenges have prompted Washington-based APR to issue a critical guidance document to assist PET bottle manufacturers in testing their labels to make sure they do not impede recycling.
“The vast majority of PET reclaimers report that the labels are a serious problem for recycling [and] a serious economic detriment,” said APR President Steve Alexander.
“Clumping is a serious issue,” said Cornell. “The labels do not readily come off the PET bottles” with the pre-wash systems many recyclers now use, he said.
APR's new protocol includes quantitative measurement related to the clumping of label material residue. It is the denser shrink sleeve labels that tend to cause the problems of clumping.
“Labels that sink in water after hot-water washing are labels that cause serious trouble,” Alexander said. “If it sinks, it is bad. We are optimistic that this enhanced protocol provides packaging designers the clear guidance to mitigate this contamination problem.”
Cornell also pointed out that PET bottles with shrink labels create problems for material recovery facilities because “the automatic sorting machines often cannot see through the labels to correctly identify the PET resin.”