Adhesive lamination is the process in which two or more flexible packaging webs are fused together using a bond agent. These webs are comprised of films, papers or aluminum foils. To bond the webs, a solventless adhesive is applied to the printed substrate. It is then pressed against the second substrate and heated to create a fuse. This results in a multi-layer laminate. Lamination is an essential step in the flexible packaging process. There are many functions of lamination including:
- To create bespoke barrier properties that protect products from external elements such as light, moisture and gas.
- To sandwich the ink and protect packaging designs.
- To improve the strength of the material making it more resistant to tearing.
The lamination process is technical and requires highly skilled operators to run. Each morning operators perform QC checks on adhesives in order to avoid the potential of delamination. This includes coating weight and mixing ratio tests. Once a job is printed, it is loaded onto the laminator and checked into the system. After consulting with the job docket, operators will load the second web material into the machine. This material is tested to ensured it is loaded correctly and has been corona treated prior to being received from the supplier. After conducting pre-checks on the materials and adhesives for the lamination process begins.
Before entering the laminator, solventless glue and hardener are pulled from individual barrels into a vat. They are heated to 45 degrees in order to create a reaction. The adhesive and hardener are pulled into the laminator and mixed in a glue tray. The printed reel is corona treated to remove any oils and ensure the material is susceptible to the adhesive mix. A nib roller evenly coats the material with glue. Both webs are pulled through the machine and meet on a heated drum causing them to fuse together. The laminated material immediately goes through a chiller to cool down and avoid any shrinkage. The finished laminate is then wound onto a core. During this process operators will conduct routine checks for bond strength and visual checks for even coverage of the adhesive.
