MATERIALS | THERMOPLASTIC ELASTOMERS


know-how to enable combinations with the lowest carbon footprint and highest recyclability,” said Klas Dannäs, sustainability director at Hexpol TPE.


Automotive focus In addition, Hexpol has collaborated with materials supplier Almaak on 2K ‘adhesion-synchronised materials’ for the automotive sector. Here, TPEs are used for two-shot or overmoulding


Hexpol and Almaak tested adhesion between a number of ETP and TPE grades


soft-touch overlays onto rigid substrates for function- al, ergonomic or aesthetic reasons. The adhesion of standard TPE is limited to olefin-based substrates like polypropylene, which have limited heat and rigidity. However, chemically modified TPEs can adhere to a wider range of engineering thermoplastics. Almaak’s products include PC, ABS and various


Source: Hexpol


Sticking together Swedish compounders Hexpol and Polykemi have collaborated on a project to make two-component (2K) consumer products. Making a material selection can be a compli-


cated task when designing consumer products, with many properties to balance, and the choice is more complex when including eco-design princi- ples. Choosing two materials for a 2K part does not double the difficulty, but squares it, say the part- ners. To help with this, the two have teamed up to enable combinations based on properties and sustainability targets. This involved combining Polykemi’s Materi-


alsmart and Hexpol TPE’s Sustainable Materials Lab to create tested solutions. “Making an informed choice is key when decarbonising and making the consequences clear is the first step on this journey,” said Henrik Palokangas, sustainability specialist at Polykemi. The partners have provided cradle-to-gate


Product Carbon Footprints (PCFs) and calculated the Global Warming Potential (GWP) per kg of material. The PCF data shows that switching away from a fossil-based ABS from Polykemi, overmoulded with a fossil-based TPE from Hexpol – to a recycled PP and TPE with bio-circular attributed content – can deliver a 77% reduction in CO2-e. This combination can also bring advantages when considering end-of-life and recycling compatibility, said the partners. Combinations using mechanically recycled ABS and bio-circular attributed TPE were also tested, which gave a 57% reduction in CO2-e compared to the fully fossil-based equivalents. The TPE has bio-circular attributed content via the mass balance principle from seond-generation feedstocks. “This project is about taking our collective


22 INJECTION WORLD | September/October 2024


nylons, which have been adhesion tested with Hexpol’s range of TPEs. Automotive applications include interior, exterior and technical parts including trim, console and interior carrier, elec- tronic housing and noise and vibration dampening. “TPEs for multi-component processes need to be adhesion synchronised with substrates, espe- cially polar technical thermoplastics,” said Thomas Köppl, group product manager at Hexpol TPE. For example, PBT is increasingly used for


electromobility applications but has difficulty adhering to TPE – with glass fibre reinforcement and flame-retardant additives making it even more challenging. “Our collaboration delivers tested material


combinations that ensure chemical compatibility and adhesion performance,” he added. The combinations have been tested to the VDI 2019 standard, which measures the adhesion between materials. TPE is moulded onto the thermoplastic and peeled off at a 90° angle. The required adhesion peel force is measured and describes the adhesion quality. Even for substrates which make bonding difficult, such as PBT, it is possible to get a good adhesion if the substrate and TPE are compatible, said Hexpol. As an example, Dryflex UV 65.01B220 TPE achieves an adhesion peel force of 3.3 N/mm on Anjacom PBT 455-GF30.


Recycled TPVs Teknor Apex has developed a new series of Sarlink thermoplastic vulcanizates (TPVs) with up to 40% recycled content. Its Sarlink RX 3100B TPVs contain post-industrial recycled (PIR) content, to ensure high processability and performance. The series was developed to help automotive


brands achieve sustainability targets, by incorporat- ing up to 40% PIR, depending on the hardness. The grades can be processed in multiple ways, includ-


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