Moisture barrier coating for paper board food packaging

Polymeric moisture barrier coating

“In the old days, everything used to be better,” is not something you’ll often hear in packaging circles. And that shouldn’t come as a surprise, because the assumption is wrong. Though some methods of preserving food in warehouses and stores are still used effectively, we have come a long way to safely maintain freshness of edible products for a longer period of time than previously possible. Still, it is also true that some of those older methods are on the rise again, be it with the added bonus of modern science to keep it all safer and more reliable. One packing method in particular has never really left: the paper/barrier coating combination. But the next step in coating paper board is a shift towards something new: a water-based acrylic coating that can be recycled.

The application of moisture barrier coatings goes back centuries

You’d be right into thinking that using barrier coatings to protect food must be a very old technique. Indeed, the age-old oiled or waxed paper has been around since at least the Middle Ages. People found out that using a sheet of paper and applying a thin coat of beeswax or vegetable oil helped to prevent moisture and odors from passing through the paper. Obviously, it also kept out sand, dirt and flies. Generally used to pack meat or fish, or bread at some point, it was a very cheap and versatile packing material. So much so, that it was able to fight off its demise into the dim and dusty land of packing methods of old. Many people still use it on a regular bases in their kitchen and it doesn’t seem to go extinct any time soon, though not from lack of trying by “team plastic”.

Development of greener paper and board coatings

We see an ever-growing demand for environmentally friendly packaging, both for food and non-food. Manufacturers are pressed to consider alternatives for all of their current plastic packaging materials. Sustainable paper and paperboard packaging is currently very much on the uprise. Though paper in itself can be very eco-friendly, some treatments can nullify their ‘green’ properties. Bleached wax paper is becoming a no-go, and so are the petroleum wax impregnated types. Traditional beeswax or vegetable oil paper seems to be a better choice, but these come with their own downsides. In comes the coated paper board. This was basically taking the wax paper idea and giving it a spin by using a modern coating.

Moisture barrier coating

Diligent scientists have recently come up with water-based coatings that have the same water vapor repelling properties as multilayer plastic film laminates, which do not hinder the repulpability of the paperboard: Acrylic coatings for paper. When the package is also printed with a biodegradable ink, the recyclability is even further enhanced. Paper board with traditional coatings can be recycled, but the result may then contain mineral oil levels up to and over 19 mg/kg, according to research. When that material is reused for food packaging, traces of the mineral oil can migrate into the packed food. It’s clear that this is not a line of direction we want to continue on. A huge advantage of the paper board with the new acrylic water-based coating is that after recycling it is still food safe. The right water-based acrylic coating should keep food-based moisture in, while repelling water and bacteria or other types of pollution on the outside of the package. This allows for a more sustainable method to protect our product from both foreign contamination or leakage.

Using moisture barrier coating in your process

Curious about this packaging innovation? Give it a try. We would be happy to help you incorporate this coating into your process and determine the right amount for your product. One or more coatings may need to be applied, depending on the desired layer thickness and barrier properties. If you want to know more about this product and its qualities, contact us for more information.

Frequently asked questions

What is a moisture barrier coating?

A moisture barrier coating is a protective layer applied to a substrate that reduces or blocks the transfer of moisture and water vapor. It helps maintain product integrity by preventing humidity from entering or escaping the material, especially in packaging applications.

How does a moisture barrier coating work?

A moisture barrier coating works by forming a continuous film on the surface of a material. This film limits the diffusion of water vapor through the substrate, significantly lowering the water vapor transmission rate (WVTR) and improving moisture resistance.

Which materials can moisture barrier coatings be applied to?

Moisture barrier coatings can be applied to a wide range of substrates, including paper, paperboard, cardboard, films, and certain textiles. They are commonly used in packaging where moisture control is critical to product quality and shelf life.

What are the advantages of water-based moisture barrier coatings?

Water-based moisture barrier coatings offer improved sustainability, lower VOC emissions, and better recyclability compared to solvent-based alternatives. They are often food-safe and designed to maintain the repulpability of paper-based packaging materials.

Can moisture barrier coatings replace plastic laminations?

In many applications, moisture barrier coatings can replace plastic laminations by providing effective moisture protection while keeping packaging mono-material or fiber-based. This supports recycling goals and reduces reliance on multi-layer plastic structures.

How do moisture barrier coatings differ from other barrier coatings?

Moisture barrier coatings are specifically designed to block water vapor, while other barrier coatings may focus on oxygen, grease, aroma, or chemical resistance. Each type targets different performance requirements depending on the application.