Honeycomb technology expert EconCore has developed new cores for laminated sandwich panels made with Sabic’s Noryl GTX resin, a blend of polyphenylene ether (PPE) and polystyrene. The new honeycomb core presents higher heat performance, better dimensional stability, and lower water absorption compared with honeycomb structures made with traditional thermoplastics. These properties enable the new core material to be used in demanding applications such as certain automotive, e-mobility, and photovoltaic components. Furthermore, combining this new honeycomb core with thermoplastic composite skins to produce an all-thermoplastic sandwich panel can facilitate recycling in combination with polyamide skins. The performance attributes and enhanced sustainability can open new market and application opportunities for EconCore honeycombs made with Noryl GTX resin.
“We turned to Sabic for expert assistance in enhancing our honeycomb cores with high-performance thermoplastics to expand our product’s use in a range of applications and overcome the limitations of incumbent [PP] materials,” said Tomasz Czarnecki, Chief Operations Officer, EconCore. “Our many years of collaboration with Sabic and the company’s broad materials portfolio gave us high confidence in the success of this initiative. We have been very impressed with Noryl GTX resin’s ease of use in conversion and appreciated the fact that it works well in our existing equipment. We believe its well-balanced properties will allow honeycomb cores to be used more widely in transportation, clean energy, and e-mobility applications,” said Czarnecki.
High-heat performance and dimensional stability
The new honeycomb structures deliver higher heat performance, greater dimensional stability, and lower water absorption than alternative materials such as polyamide, according to EconCore. Thanks to this high performance, the cores may also demonstrate good compatibility with thermoset composite skins. Because the honeycomb exhibits high load-bearing capacity, even at temperatures up to 180°C, it may also be a good candidate for lamination with thermoset prepregs in processing environments where high curing temperatures are typically applied. The honeycomb also potentially can be used for applications where sandwich panels must deliver high performance at elevated temperatures.
EconCore honeycombs are produced from a single, continuous thermoplastic sheet using the company’s patented technology. In this unique process, the material is extruded and in-line formed into the honeycomb structure without the need for secondary operations. Specifically, this involves a sequence of extrusion and thermoforming steps to transform the extruded film into a half-hexagonal web that is directly folded into a thermoplastic honeycomb structure.
The high efficiency of this continuous process minimizes production costs, making the product very competitive economically. Furthermore, the technology allows for integration of the skin lamination step in-line with the honeycomb core production, providing opportunities for effective, continuous manufacturing of value-added laminated sandwich panels.
Expanded design possibilities
EconCore’s technology also offers expanded freedom to design and produce a range of honeycomb cell sizes, core thicknesses, and densities. The company has licensed its integrated technology for production of lightweight honeycomb panels in specific configurations to several leaders in the industrial packaging, automotive, transportation, and building and construction industries.
Sabic’s Noryl GTX resin provides up to 240°C (465°F) heat resistance during processing, with conductive grades that may be used in powder-coated automotive body panels. Compared to polyamide, Noryl GTX PPE resin has lower water absorption and a lower density, reducing part weight. This material offers excellent impact performance and stiffness across a wide temperature range. Sabic is also currently developing a new grade with extreme low-temperature impact performance for potential use in honeycomb cores for electric vehicle (EV) battery protection.