Aquapak Polymers’ soluble barrier polymer found effective as plastic-replacement in fiber packs

06 May 2021 --- Research by UK-based Aquapak Polymers has found the company’s Hydropol resin can act as a “recycle-ready,” fully soluble adhesive to replace plastic in fiber packaging.

The research comes as a growing number of packaging manufacturers turn to fiber-based materials in the face of increasingly stringent plastics regulations, but remain reliant on hard-to-recycle plastics to add functionality.

This combination results in large amounts of paper packaging being rejected from recycling streams as the materials cannot be easily separated. 

Aquapak’s CTO, Dr. John Williams, tells PackagingInsights findings solutions to these issues is essential. 

“Industry is facing financial and environmental penalties because most current complex packaging cannot be recycled technically or economically. It is imperative material constructions maintain functionality but allow recycling – Hydropol is the enabler to do this.”

Road to commercialization 
Hydropol is a fully soluble, bio-digestible barrier polymer that can be adhesive or extrusion coated onto paper. The polymer can bring many benefits to fiber-based packaging, including oil and grease resistance together with a high gas barrier.

A pouch of Hydropol resin pellets.The solution has also been shown to increase some paper strength properties (tear, burst, puncture and tensile strength), allowing coated or laminated papers to be heat-sealed for “form, fill and seal” fiber packaging applications.

While already commercially available, Williams asserts it will take more time and research to broaden the scope of applications for the material. 

“As we widen our potential application, then like all specialty polymers, there is a learning curve for the converters to enable processing of the Hydropol,” he notes.

“We have full technology transfer guidance, but new applications take time to ensure scale-up capability. It is not only ensuring the running of the polymer, but all the regulatory and test data has to be collected to ensure compliance.”

Aquapak is currently working on combinations with existing materials and emerging bio-based and cellulosics to “give a whole new spectrum of functional, circular economy polymers,” continues Williams. 

“We have our internal R&D working with 11 external universities on characterization, crystallinity control, heat seal and end of life to enhance and develop this material further.”Paper coated with Hydropol.

Saving paper, saving money
The study results confirm that most laminating adhesives can disrupt the recycling loop by locking in valuable fiber and, in some cases, result in more than a quarter of fiber associ­ated with some laminated adhesive packs being lost from the paper recycling process. 

Aquapak Polymers explains that using non-repulpable laminating adhe­sives could consign paper and board packaging to the “Don’t Re­cycle” category – an undesirable outcome for producers, brands and retailers turning to paper fiber-based packaging as the “green” alternative to plastic.

In terms of cost, Hydropol is comparable in many applications to “the current failing solutions and emerging bio-based systems, which often lack functionality or scale,” says Williams.

“Comparing it as a specialty polymer to a commodity like polyethanol (PE) is one-dimensional, since if the target is to replace PE with a circular economy solution, then that solution comes with an added cost – essentially, are you serious about it or not?”

By Louis Gore-Langton