Use of waxes and rubbers to create SUPD-compliant coated packaging

The Single-Use Plastics Directive, or SUPD came into force on 3 July 2021 in the European Union in 2021. The main goal of the SUPD is to reduce the amount of plastic waste in the environment, especially the marine environment. SUPD restricts material choice in cotton bud sticks, cutlery, plates, straws, stirrers, sticks for balloons, cups, food and beverage containers. Synthetic polymers and oxo-degradable plastics are forbidden. This work was performed to create and assess SUPD-compliant natural options available to replace these plastics. Waxes and rubbers are some of the most common naturally available materials which impart water vapor and oxygen barrier properties. Different waxes - rice bran, carnauba, rapeseed, beeswax and rubbers - caoutchouc, guayule and chicle - and their combinations were tested in different ratios. They were coated on paperboard using different techniques like dispersion coating, hot melting coating in single and multilayer forms and their barrier properties were measured. The key target of this research was to identify the best options which can provide barrier properties, heat sealability and good printability. Out of the various options tested, rice bran wax provided a good moisture barrier whereas rubber helped in providing heat-sealability and a printable surface. A water vapor transmission rate (WVTR) in the range of 3-5 gm/m2/24 hr at 23 °C and 50% relative humidity was achieved with a multilayer product.