You knew that birds migrate for the winter, but did you know that the ink on the outside of your packaging could also be migrating?
Unfortunately, the same ink that created your gorgeous packaging can also seep through and make your food or beauty products unsafe to use. That’s why it’s so important for you to know what ink migration is and how to prevent it in your packaging.
What is ink migration?
Put simply, ink migration occurs when the ink on the outside of your package bleeds through to the inside of your packaging and comes into contact with your product. As you might imagine, no one likes the taste of ink, and they don’t want to put it on their skin, either. While some packaging has a separate, inner layer that protects the product inside, more products are being encased in only one layer of packaging. While that’s better for the environment, it means that ink migration is even more of a concern than it used to be.
Different types of migration
There are three different types of migration that commonly occur with food and beauty packaging.
In diffusion migration, some types of ink are able to migrate from the printed side of your packaging onto the unprinted side and come into contact with the product inside. This occurs because of the chemical characteristics and molecular size of the inks and how they interact with the materials you are using for your packaging.
In set-off migration, the ink migrates from the printed side of one package to another package in a stack. This is common when cups are stacked together or when a press is running so quickly that it sends sheets that aren’t completely dried to be stacked on top of other sheets.
Gas phase migration
Gas phase migration happens when food is heated in its original packaging. The steam and temperature changes cause the migration to occur.
There are a number of things that affect ink migration:
- The material of your packaging
- The ink printers use to print your packaging
- The process printers use to print and cure the ink
- The temperature and storage time
Migration and packaging material
Packaging materials like stainless steel, ceramic, and glass, do not allow migration from one side of the packaging to the other. That’s because the pore sizes of the materials are so small that they prevent migrants from coming through.
However, materials like paper, cardboard, and plastic have larger pores that are more likely to let migrants through to the other side. If you choose to use paper, cardboard or plastic for your packaging, you must be more careful that you choose low-migration inks. You can also prevent migration by adding a layer of packaging between your outer package and the food.
Low-migration inks and adhesives
Manufacturers are making new inks and coatings that are low-migration while also producing a high level of quality. These inks have larger molecules, so it’s more difficult for them to bleed through your packaging. They are also formulated to cure with UV radiation, which makes them safer and more predictable to print with.
Many green printers only used vegetable or soy-based ink, which is more cost effective and better for the environment in addition to being safer for your food packaging. Vegetable-based ink has low levels of Volatile Organic Compounds or VOCs, which are pollutants that evaporate in sunlight and are hazardous to your health and to the environment.
The amount of ink is also a concern when it comes to ink migration. If your design requires less ink, you may not need to worry about low-migration inks as much.
If you are using adhesives on your packaging, make sure that you choose the right ones, because adhesives can also migrate.
How printing and ink curing (drying) affect migration
You can’t just contact a printing company and get a pre-made low-migratory ink. Kristin Adams, the marketing manager for Collins InkJet, told packagePRINTING, “The term low-migration actually defines the selection of materials as well as the ink. So regardless of how an ink is formulated, the ink alone cannot be considered low-migration until it’s actually applied to a specific substrate (material).”
She added that printing food packaging is more complex than just using a pre-made bottle of ink. Rather, printers need to understand the type of material being used, print speeds, and the ink curing process in order to produce safe packaging. The same ink may migrate at one curing speed and not at another.
Transport and store your products carefully
After your packaging is printed, it is still at risk for ink migration. Make sure that your products are stored at the right temperature, moisture level, and ventilation to ensure that ink migration does not occur.
How do you ensure that your packaging is safe from ink migration?
Ink migration can contaminate your food or beauty product and make it unsafe to consume, so it’s essential that you take steps to ensure that your packaging is safe.
To prevent ink migration, work with a printer who specializes in packaging for products where ink migration is a concern (like food and beauty products). Some printers have testing facilities that they use to make sure that ink migration does not occur in the printing process.
Also, be certain that open communication is established between everyone in the production chain, including the printers, the manufacturers, and even the companies who are transporting and storing your products.
Are you looking for a packaging designer for your food or beauty product?
I specialize in designing packaging for food and beauty products, and I would love to work with you to create a design that reflects your brand and vision. Contact me to learn more.