Novel coating formulation for recyclable paper for food packaging
A novel coating formulation combining water-soluble hyperbranched polyester and modified nanoclay to enhance water vapor barrier properties of paper while preserving recyclability for sustainable food packaging applications.
Overview
Paper packaging offers a sustainable alternative for food products, but its poor water vapor barrier properties limit its use for wet or moisture-sensitive foods. Traditional protective coatings solve this problem but prevent paper recycling, undermining the sustainability advantage. This research proposes a novel coating formulation that enhances the water vapor barrier of paper without sacrificing recyclability, enabling truly circular food packaging solutions.
The coating is composed of modified nanoclay combined with a water-soluble hyperbranched polyester. The hyperbranched polyester, with its large number of end groups, effectively anchors nano-kaolinite treated with dodecyl amine, creating a robust barrier layer that can be removed during standard paper recycling processes.
Technical specifications
Key features:
- Water-soluble hyperbranched polyester prepared from multifunctional monomers and modified for water solubility, enabling easy removal during recycling
- Modified nanoclay (kaolinite intercalated with solvents and dodecyl amine) for enhanced barrier performance
- Coating formulation combining the water-soluble polymer with nanoclay at optimized ratios
- Applied as a surface coating on paper sheets to improve vapor barrier properties
- Designed to maintain mechanical properties and grease resistance of the base paper
The approach builds on prior work demonstrating that polymer coatings with nanoclay can dramatically reduce water vapor transmission rates. The hyperbranched polyester architecture provides multiple anchoring points for the nanoclay, creating a tortuous path that slows vapor transmission while remaining water-soluble for recyclability.
Technology readiness level
This technology is at an early research stage (TRL 2-3). The research team has established the hypothesis basis through prior work on nanoclay exfoliation using hyperbranched polyamide amine. The future validation plan includes: (1) synthesis of water-soluble hyperbranched polyester, (2) intercalation of kaolinite with dodecyl amine, (3) preparation and optimization of the coating formulation, and (4) coating of paper sheets and evaluation of vapor barrier properties. The estimated timeline is one year, contingent on access to required materials and paper testing facilities. Funding is needed to acquire materials and perform testing.
About National Research Council
Consiglio Nazionale delle Ricerche (CNR) is Italy’s national public research organization, a large multi‑disciplinary network of institutes distributed across the country and coordinated from Rome. Its model places researchers in regional campuses and co‑located laboratories next to universities, hospitals, and industry, enabling rapid collaboration and access to shared core facilities, testbeds, and prototyping. Companies engage through framework agreements, contract research, joint labs, and researcher secondments, with dedicated liaison staff to streamline engagements. Research is supported by competitive funding from the European Commission, Italian national ministries, and regional programs. A technology transfer office advances IP protection, licensing, and spin‑out formation.
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