In 2020, INEOS Styrolution developed the idea of binding biomass like cork granules with Styroflex, a unique styrene-based material with very high flow at compounding temperatures above 150°C[2]. Two years later, the company began to explore if Styroflex can indeed act as a binder for cork granules. Ultimately, a solution was found with the help of a ring extruder (above image, left to right: various stages of cork production with Styroflex).

Styroflex is a styrene-butadiene block copolymer (SBC) with the properties of a thermoplastic elastomer (S-TPE) that is suitable for extrusion (including both blown and cast film) and injection molding. The product demonstrates high resiliency, toughness, optical clarity and process stability. In film applications, Styroflex provides excellent stretch recovery, puncture resistance, superior transparency as well as high oxygen and moisture permeability. Key applications for Styroflex include medical tubes, stretch hoods, impact-modified compounds and flexible films.

Styroflex is currently cleared for a range of food contact applications, however, further testing is being planned for the cork binder application to ensure all food safety requirements are met. .

Stefan Meier, Business Development Manager at INEOS Styrolution, stated: “The amazing properties of Styroflex make it the material of choice for a very broad range of applications. I look forward to popping a Styroflex cork on a lovely bottle of wine in the future.”

[1] SBC: styrene butadiene copolymer
[2] See Order-Disorder Temperature of Styroflex in: N. Niessner at Global TPE Summit Barcelona, December 2015