Rubber composite coatings for high-performance paper barrier applications

Overview

This technology centers on uncrosslinked rubber latex composites formulated with mineral and cellulosic fillers to create high-performance barrier coatings for paper substrates. By combining the hydrophobic nature of rubber with the platelet morphology of fillers such as silicates, clays, silica, calcium carbonate, and cellulosic materials, the coatings deliver complementary barriers against water vapor, oxygen, grease, and oil. The result is a flexible, tough coating layer that seals paper pores and enhances mechanical performance. A key sustainability advantage is that the uncrosslinked rubber can be recovered during re-pulping and reused in other rubber applications such as conveyor belts, o-rings, or tire formulations, supporting circular economy goals in the paper and packaging industry.

Technical specifications

Key features:

• Aqueous rubber latex systems including styrene-butadiene, nitrile, and deproteinated natural rubber, with solids content around 60 wt%
• Mineral and cellulosic fillers including silica, clays, calcium carbonate, and cellulosic fillers at optimized loading levels
• Target solid loadings greater than 40 wt% in the coating formulation
• Dry coating thickness of 10 to 25 microns, with demonstrated performance at approximately 20 microns (about 13 g/m²)
• Improved wet strength and modulus while maintaining flexibility and fold resistance
• Effective sealing of paper substrate pores to enhance barrier properties against oil, oxygen, grease, and water vapor
• Recoverable rubber component during re-pulping for reuse in conveyor belts, o-rings, or tire formulations

Technology readiness level

The technology has progressed beyond early concept validation. The research team has successfully demonstrated natural rubber latex and polysaccharide composite paper coatings, showing notable improvements in wet strength, modulus, barrier performance, and fold resistance at optimized filler concentrations. The next phase of validation will extend these results by evaluating multiple rubber latex types and mineral filler combinations, optimizing filler loading and dispersion, and tuning barrier and mechanical properties. Additional work will focus on confirming the recoverability of the rubber coating during re-pulping processes to ensure recyclability and reuse in downstream rubber applications.