Flexible packaging offers many benefits, including lighter-weight packaging solutions for reduced cost and a lower carbon footprint. At the same time, multi-layer flexible packaging solutions today are not generally amenable to recycling and, therefore, are often single-use and not considered sustainable. The packaging industry is committed to addressing this issue, and functional coatings might be a key to the solution.

The global market for flexible packaging is, according to market research firm Grand View Research, expanding at a compound annual growth rate (CAGR) of nearly 4.7% from a value of $221.82 billion in 2016. Flexible packaging is used most widely in the food and beverage industries, but also has applications in the pharmaceutical and medical, cosmetic and personal care, pet food, consumer goods, and industrial sectors. Coatings, including acrylics, epoxies, and polyurethanes, among others, are used to enhance the appearance and/or functionality of flexible packaging solutions. The global market for flexible plastic packaging coatings was valued by Transparency Market Research at $1.53 billion in 2017 and is forecast to expand at a CAGR of 4.0% from 2018 to 2026.

Flexible packaging offers brands a lightweight and more durable option through the shipping process and minimizes costs associated with production, returns, and shipping, according to Arica Drake, global marketing manager, Flexible Packaging at Michelman. “As e-commerce continues to grow, there is no denying the importance of safe and effective packaging. E-commerce brands are leveraging flexible packaging by using a wide range of material options, shipping more product with less weight, and protecting products from exposure to oxygen and moisture,” she says.

In addition, flexible packaging is being used to enhance the consumer experience. “Through the use of different haptics coatings, brand owners can use packaging to not only protect and safeguard their products, but also to communicate their brand messages,” Drake observes. These coatings range from matte finishes to different textures including soft touch, velvet feel, sandy or course feel, and various combinations. As such, haptics coatings can provide packaging differentiation with different visuals and textures and be utilized to convey messages that denote premium, natural, or “good for you” products, she notes.

Through the use of different haptics coatings, brand owners can use packaging to not only protect and safeguard their products, but also to communicate their brand messages.

The key challenge with flexible packaging is its lack of recyclability, at least for current multi-layer technologies. “Currently,” comments Drake, “recycling flexible packaging is difficult due to the multiple layers of different materials used to achieve packaging performance.” Most new regulatory developments stem from the desire to improve the sustainability of packaging. Drake points to many new material-use bans, and in particular those targeting single-use plastics. Other initiatives require the use of recycled content in flexible packaging. While some of these initiatives are official bans or requirements, others are goals for future years, according to Drake. She notes that many companies are signing on to the Ellen MacArthur Foundation’s New Plastics Economy Global Commitment, which has targets including:

  • Elimination of problematic or unnecessary plastic packaging and movement away from single-use to reusable packaging models;
  • Innovation to ensure 100% of plastic packaging can be easily and safely reused, recycled, or composted by 2025; and
  • Circulation of the plastic that has already produced throughout the economy by significantly increasing the amounts of plastics reused or recycled and made into new packaging or other products.

As flexible packaging manufacturers seek solutions for improving sustainability, they are frequently turning to coatings. Coatings are being developed to replace some of the layers of polymers traditionally used in flexible packaging, providing needed functionality while having minimal impact on recyclability, according to Drake. For instance, she notes that a polyester film with an applied coating can go through the polyester recycle-stream successfully, while a polyester film extruded to a polyethylene layer cannot.

Performance requirements vary depending on the product being packaged. Food and beverage coatings should be compliant with U.S. FDA regulations (or similar organizations’ regulations in other countries), while all coatings used in the medical segment have requirements for sterilization processes, for instance. Within the food sector, different products often have different requirements. Packaging for a fresh meat product will have different functionality needs than packaging for a confectionary product, according to Drake. “Fresh meat generally needs coatings that provide an oxygen barrier to prevent bacteria growth, a moisture barrier to keep the meat moist in the package, and excellent clarity to allow the consumer to inspect the meat before purchasing. A confectionary package might not need a strong oxygen barrier, but may need a moisture barrier to prevent the product from becoming soggy. It may also require a coating that can be sealed at low temperatures, because many confectionery products contain chocolate, which is very sensitive to heat,” she explains.

Coatings are being developed to replace some of the layers of polymers traditionally used in flexible packaging, providing needed functionality while having minimal impact on recyclability.

New flexible packaging solutions with mono-material structures that are recyclable are being developed by flexible packaging producers. Coatings are playing a vital role in these structures by adding functionality that might be missing due to the elimination of other polymer layers. “A full polyolefin pouch, for instance, is recyclable with other polyolefin materials. However, while polyolefin materials provide a good moisture barrier, they are considered very breathable. For oxygen-sensitive products, therefore, an oxygen barrier coating can be applied to the structure to add that functionality without affecting the recyclability,” Drake observes. She adds that polyolefin materials are not very heat-resistant during package production, creating the possibility of material distortion, which can negatively impact appearance. “Here again,” she says, “a coating can be used to give the structure heat resistance while still maintaining recyclability.” These types of developments are available today, but Drake believes additional improvements in technology will be introduced over the coming years so that sustainable packaging will be able to meet or exceed the performance and economic needs of current packaging.

Michelman offers a wide range of water-based coatings designed specifically for the flexible packaging market. These coatings include primers, barrier coatings, overprint varnishes, and heat-seal coatings. Recently, the company introduced a clear, water-based, high-oxygen-barrier coating designed for use on plastic packaging films. According to Drake, the coating is very durable, can withstand flex cracking, and can be combined with metallization and other barrier coating processes for protective and enhanced oxygen barrier performance. Michelman is also working on a portfolio of haptics coatings that will be launched in 2019, including a variety of matte and gloss finishes, soft touch and sandy coarse feels, and an anti-skid coating.

CoatingsTech | Vol. 16, No. 3 | March 2019