Flexible packaging are predominately based on urethane and acrylic chemistry. Backbone options create unique performance properties. Changes in composition determine whether it will be solvent or solventless adhesive.
Flexible packaging for foods and other consumer goods has been around for a long time and now is essential for efficient distribution, protection and economics. Today’s packaging could not exist in its myriad forms and functionalities without, amongst many other components, the integral part played by flexible packaging adhesives.
There are many isocyanates available for industrial use, but only a limited number approved by food laws useful for packaging adhesive. The two general classes of isocyanates are aromatic and aliphatic. Aromatic isocyanates are faster reacting, depending on their chemical structure. In the aliphatic class, typical ones include isophorone diisocyanate, and hexamethylene diisocyanate, other aliphatic material are used for more specialized adhesive applications.
The aliphatic isocyanates are much more costly than aromatic. They bring different, often unique and safer chemistry for elevated temperature packaging. In some applications, only the aliphatic isocyanate is permitted by food law regulation.
