Laminated and silanated recyclable paper for food packaging applications

Overview

This project develops a fully recyclable paper-based barrier material for food packaging that can replace conventional multi-layer plastic films. The approach combines a smooth, low-porosity cellulose film with a thin silica-based glass-like coating to block water vapor transmission. During recycling, the cellulose layer dissolves back into pulp while the silica layer breaks apart into nanoparticle fillers, allowing the material to be reintroduced into standard paper recycling streams without contaminating the process.

The technology addresses a critical sustainability challenge in the food packaging industry, where multi-material plastic laminates are difficult to recycle and contribute significantly to packaging waste. By using cellulose and silica, both abundant and non-toxic materials, this solution offers a path toward truly circular packaging materials with performance comparable to conventional plastics.

Technical specifications

Core technology:

• A smooth cellulose-based film produced by extruding a dope solution into an acid bath through a slit, yielding defect-free films with near-zero porosity
• Film thickness range of 10–30 µm, made from chemically modified kraft fibers or office waste paper
• Film densities up to 1.4 g/cm³, approaching the density of pure cellulose
• A silica-based coating applied via silanation that forms a thin, glass-like hydrophobic layer

Current performance characteristics:

• Tensile strength of 60–150 MPa, comparable to many plastics
• Elongation at break of 2–15%
• Young's modulus of 3–6 GPa
• Oxygen barrier properties expected to be similar to conventional plastics
• Current water vapor transmission rate of approximately 300 g/m²/day — too high for packaging applications, requiring a 2–3 order of magnitude reduction through the silica coating

Recyclability:

• Cellulose layer dissolves during repulping and returns to the paper recycling stream
• Silica layer fragments into nanoparticles that act as inert fillers within the recycled paper

Technology readiness level

This technology is at an early-to-mid stage of development. Proof-of-concept work has already demonstrated the ability to produce defect-free cellulose films with near-zero porosity and has characterized their mechanical and barrier properties. The key remaining challenge is achieving a sufficient reduction in water vapor transmission rate through the silica coating.

A proposed one-year validation project will optimize key parameters including the extent of cellulose carboxylation, cellulose layer thickness, drying conditions, and the choice and extent of silanization agent. Both batch laminates and a continuous lamination process — combining wet paper substrates with wet cellulose layers followed by drying and silanization — will be developed and tested. Estimated project cost is $100K. Upon successful demonstration, the technology would advance toward pilot-scale production and eventual commercial deployment in food packaging applications.