Recyclable silsesquioxane/siloxane hybrid vapor barrier coatings for paper packaging

Overview

This technology offers a recyclable, high-performance vapor barrier coating for paper-based packaging and other cellulose-fiber substrates. The coatings are based on phenyl-rich silsesquioxane/siloxane hybrid polymers that provide water vapor and oxygen exclusion at levels competitive with conventional multilayer barrier films, while remaining compatible with paper recycling streams. A patent-pending fluoride-catalyzed depolymerization process enables the coating to be broken back down to its starting materials, supporting circular-economy objectives and reducing reliance on petroleum-derived barrier films.

The solution targets packaging converters, brand owners, and manufacturers seeking to replace non-recyclable barrier laminates with a single-component, recyclable coating applied through standard printing and converting methods.

Technical specifications

Core technology:

• Phenyl-rich silsesquioxane/siloxane hybrid polymers engineered as vapor exclusion layers
• Target water vapor transmission rate of 0.26 cc/m² and oxygen transmission rate of 2.75 cc/m²
• Application thickness range of 5–15 microns

Application methods:

• Compatible with flexographic printing and co-extrusion processes
• Also demonstrated via dip, roll, spray, and wipe coating methods
• Tunable cure technologies, including photo-cure systems

Performance characteristics:

• Slightly hydrophobic surface with tunable water contact angles between 92° and 110°
• Improved compatibility with wood fiber substrates compared to typical silicones
• Environmental stability demonstrated against water submersion, sunlight, and acid exposure
• Environmental stability validated over a one-year period
• Designed for flexibility sufficient to support folding operations

Recycling pathway:

• Patent-pending fluoride-catalyzed depolymerization returns the coating to starting materials
• Applicable to bulk silicones containing both methyl and phenyl groups
• Enables recovery of coating material from coated substrates

Planned enhancements:

• Viscosity tuning across a 200–600 cp range for diverse converting equipment
• 2–6% elongation through siloxane elastomer components for improved flexibility
• Incorporation of aminoalkylsilane and epoxysilane adhesive groups for metal can-closing adhesion
• Exploration of dynamic covalent and hydrogen bonding chemistries for recycled-content formulations

Technology readiness level

The coating technology has been demonstrated at laboratory scale, with multiple application methods validated on stones, metals, wood, plastics, and other substrates. Environmental stability has been confirmed over one year of testing, and the fluoride-catalyzed depolymerization recycling process has been demonstrated on bulk silicone systems. The current stage focuses on adapting the formulations specifically for paper substrates and optimizing viscosity, flexibility, and adhesion properties. The research team estimates an additional 9–12 months to complete validation of the paper-specific coating performance and recycling workflow. The technology is positioned for collaborative development with packaging industry partners to advance toward pilot-scale demonstration.