Lanxess, a leading global manufacturer of synthetic rubber, will showcase a broad range of products for the rubber transformation, automotive, tyre, and civil construction industries, among others at the Expobor 2014, Latin America’s largest rubber fair, held in late April at Expo Center Norte, in São Paulo.
At this year’s edition of Expobor, Lanxess Keltan Elastomers business unit will present an innovative curing technology for EPDM rubber. According to Lanxess’s rubber experts, zeolite can be used as a new co-activator for resol curing, enabling both high cure speed and high curing efficiency. Resol curing opens up an alternative approach of EPDM rubber processing besides established sulphur vulcanisation and peroxide curing which are the main crosslinking technologies for EPDM rubber.
So far, resol curing could be designated as the “work horse” for the dynamic vulcanisation of EPDM/PP-based thermoplastic vulcanisates (TPVs). However, for thermoset vulcanisation of EPDM it is hardly used, because it is considered to be too slow and suffers from marching cure.
Dr Niels van der Aar, Head of Technical Service & Application Development at Keltan Elastomers, explains: “Although emphasis of our studies is on the activation of various resol curing systems for EPDM rubber, it is also shown that this novel way of activation is applicable for resol cure of other types of rubber, including (X)IIR, CR, (H)NBR, BR, SBR and NR.”
Depending on the particular resol curing system and rubber under investigation, the cure rate is strongly increased. This means a reduction of scorch and vulcanisation times up to 75%. Furthermore, the final degree of crosslinking is clearly enhanced – almost up to the double value.
“Resol curing can now be considered as a realistic alternative to sulphur and peroxide curing systems making curing at lower temperatures possible and giving, for example, improved heat aging properties,” says van der Aar. “Finally, it will also be shown that zeolite activation is effective not only for the thermoset vulcanisation of EPDM, but also for the dynamic vulcanisation of EPDM-based TPVs, enabling a reduction of the resol content and, thus, improving the TPV colour characteristics.”