Andy Kerr, international technical support specialist for API Foils says: “It would seem that the world recession has created a need for cheaper materials and less protective coatings, and from this we have seen a proliferation of problems with corrosion.”
According to the UK-headquartered company – part of the API Group, and a worldwide supplier of metallic, pigment, holographic and cold foils – cases of corrosion on metallised labels and decorative packaging have “increased significantly” since 2010.
“If the correct combination of materials and conditions are not met then any metallic foil will be susceptible to corrosion,” the company says.
Most corrosive reactions are said to result from substances on the substrate reacting with the aluminium layer as a result of an “insufficient protective adhesive layer”, and the effects are “easily visible”, due to the fine nature of the aluminium layer.
Kerr says there has been a “golden era” during which cases of foil corrosion have been rare. “We now have a great many customers who have never seen corrosion nor had any experience of it,” he says.
“We therefore have an important job to do in educating our customers and the end user to prevent this costly but fully avoidable type of damage and degradation.”
Measures suggested by API Foils to help avoid the problem of corrosion include using the most stable grade of aluminium; coating black inks and paper with a sealant or varnish prior to blocking; ensuring the substrate is not excessively wet; keeping the substrate free from salts; and using a pH neutral adhesive.
