Process Spotlight: Lamination
With low minimum order quantities, quick speed to market and the ability to create bespoke packaging solutions tailored to specific product needs, it’s not surprising that digitally printed flexible packaging is the first choice for many retail brands. That being said, there is a lot that goes into producing our award-winning packaging. From design to quality control, this series will give an in-depth insight into the process of producing digitally printed flexible packaging.
Following on from our blog post highlighting the digital print process, we’re going to give you a breakdown of the lamination and curing processes which are an integral part of creating bespoke flexible packaging solutions. Flexible packaging is unique in that the materials used to make up a piece of packaging can vary depending on the barrier requirements of the product. For example, if a product is sensitive to light, including a foil barrier will provide high levels of UV protection. Material structure is typically recommended by our experienced sales team and agreed upon at the order stage but in production, lamination is where the bespoke structure is created.
What is lamination
Laminating is the process in which two or more flexible packaging webs are fused together using a bonding agent. These webs are comprised of films, papers or aluminium 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
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 DYN tested to ensure 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 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.
Once the reel has been laminated the operator logs details of the job into the system and labels the reel for traceability. This information includes time, date and batch numbers. The non-printed material is recovered, labelled and brought back to the warehouse. The laminated reel is taken to the curing room and placed in a numbered bay. The curing room is temperature-controlled so the material will stay between 30 and 35 degrees for 24 hours before continuing on its way through the flexible packaging production process.
At the end of each day, the laminator is thoroughly cleaned by its operator. This process can take anywhere from 45 to 60 minutes to complete. Every part of the machine that houses adhesive must be cleaned thoroughly using acetate. This includes hoses, rollers and the glue tray. Routine cleaning of the laminator ensures it runs as efficiently as possible and produces food-grade laminates with excellent bond strength
If your brand is looking to invest in quality packaging, our team will guide you through the entire process, providing recommendations on increased sustainability, helping to improve efficiencies and adding expert and award-winning value to your end product.