Technology focus: Advanced processing properties
17 Jul 2026
New Struktol additive said to enhance performance of rubber extrusion and moulding compounds
Stow, Ohio – Struktol Company of America, part of the Schill+Seilacher group, has launched a new processing additive developed for applications in both natural rubber (NR) and synthetic rubber.
Engineered as a blend of fatty acid derivatives, predominantly zinc soaps, Strukol EF 44A is designed to enhance mixing and flow across a wide range of elastomers, stated the additives technology specialist.
Comprising fatty acid derivatives with different polarities, the additive is said to enhance flow and handling of compounds including those based on NR, SBR, and EPDM – though excluding halogenated materials.
According to Struktol, the product enables compounders to achieve “smoother mixing, improved flow, and more efficient production in diverse rubber formulations.”
For extrusion, EF 44A is said to support smoother throughput and better finished-part consistency via improved processability, while moulders – transfer and injection – can benefit from enhanced mould-filling and mould-release performance.
Moreover, by improving dispersion of fillers, especially mineral fillers, the product “supports more uniform compound characteristics and more reliable end-product performance,” continued Struktol.
EF 44A is also said to act as a cure activator and allow for reduced dosage of stearic acid: helping formulators to simplify recipes and potentially lower the need for separate additive inputs within the compound.
Supplied in pastille form, the additive has a dropping point of 91–101°C, a specific gravity of 1.10, and a maximum zinc content of 9.0%. Recommended dosage is 1-3phr.
