The company claims that this can be a problem for items with a long shelf life and can affect the taste of products, particularly if they are in liquid form, over time.
The patent (No 6,472,056) covers ultraviolet light/electron beam (UV/EB) laminated labels for use on pharmaceutical and food grade products.
"Prior to this invention the migration of adhesive components was found to be an issue for UV laminated pressure sensitive paper labels used on high-density polyethylene (HDPE) containers stored for long periods under non-refrigerated conditions,"according to the company.
One monomer that was linked to taste and odour problems was HDODA. While it is a fairly simple matter to remove HDODA from a UV laminating adhesive, it was found that many types of common monomers used to replace HDODA could also migrate through polyolefin containers.
Northwest Coatings' new monomer technology is highly resistant to migration through the containers but also provide excellent bonding and very low odour characteristics. This approach is already being used in a family of Northwest Coatings UV and EB laminating adhesive products including 15615LA.
The adhesive technology can be applied equally to rigid and flexible laminate packaging, according to the patent.