Spur offers Hardex structural foam core as alternative to low-weight cores in sandwich composites

Spur (Zlín, Czech Republic) is a family-owned, polymers and plastics processing company that produces Hardex XPP (extruded polypropylene) Performance foam core, which can be used for composite sandwich structures offering high mechanical properties with low weight such as floors and interiors in automotive, trucks and recreational vehicles (RVs), as well as furniture and profiles in the construction industry and a variety of marine applications. This is due to its high strength-to-weight and water resistance. Its insulation properties are also valued in structural insulation panels (SIPs). To learn more, watch the Spur webinar hosted by CompositesWorld on May 24, 2023, “Thermoplastic Foam Cores for Composites: Light, Productive, Recyclable XPP.”

Spur’s history reaches back to 1934, though the entity as it stands today was founded in 1992. Its focus is on the future, developing the latest technology including automation and recycling. Spur upcycles 600,000 kg of material per year, purchases 1,000t of additional recyclate (such as PET flakes from bottles) and is a supply partner in the award-winning Better Shelter project, improving the lives of thousands of refugees worldwide.

Spur puts forward its Hardex XPP closed-cell foam materials as an alternative to other closed-cell cores for composite sandwich structures. Hardex XPP materials are fully recyclable and can also comprise significant recycled content. They offer high resistance to moisture and chemicals, impact toughness and thermal insulation. Ultraviolet radiation (UV) resistance and enhanced resistance to fire can be added on request.

Spur says its material can be cut and processed similarly to wood materials and joined using screws, nails and glues — or adhesives can be eliminated by using fusion welding, hot air welding r ultrasonic welding. Functional and aesthetic surfaces can be similarly attached. Hardex XPP can be used with temperatures up to 150°C and is thermoformable. It can be heat laminated to polypropylene (PP) composite skins, resulting in a monomaterial panel without glue or adhesives that is easily upcycled — as Spur already performs on a daily basis. The production speed of this panel is usually 2-10 times higher compared to similar panels glued by the more traditional method of reactive adhesives. Examples of PP composite skins include glass fiber/PP used, for example, by mobility companies for lightweight, low-cost, composite body panels.

Spur reports that its Hardex XPP Performance foam cores offer slightly better mechanical properties than PS and PET foam cores or PP honeycombs in comparable densities.

Hardex XPP Performance materials are available in densities from 40 to 200 kg/m³ and with thickness from 3 to 100 mm. Standard panel size is the same as with most closed cell foams: 1,220 × 2,440 mm.