In the packaging industry, a wrapper is a multi-layered structure that is usually formed by sticking flexible films with a thin layer of glue. Each of these layers has its own unique properties and plays a specific role in product packaging.

One of the most common methods of laminating different types of polymer films (transparent, shell, metallized) with each other, even with aluminum, is the use of two-component polyurethane adhesives without solvents, under the necessary pressure and temperature; which includes an active resin component with functional groups and a relatively low molecular weight hardener with a specific percentage composition.