Rubber chemistry expertise remains a key mainstay of the Lanxess Rhein Chemie Additives business unit. This is demonstrated through its comprehensive portfolio of processing promoters for silica tire compounds. The available processing promoters can be divided up into neutral, basic and acidic mixtures.
Vulcanization times in the mixing process can be adjusted according to the choice of pH value. The neutral processing promoters, Rhenofit STA/S, a dry liquid, and GE 2340 hardly influence the vulcanization time. Lanxess’s acidic grade Aflux 37, supplied as pastilles, delays vulcanization, whereas the basic grade GE 2434 reduces cure time.
Processing promoters’ purpose is to reduce the compound’s viscosity and to distribute fillers as homogeneously as possible in the rubber compound. Mixing and processing times, energy consumption, surface quality, dimensional stability and mold fouling can be optimized through the use of Lanxess’s processing promoters. Aflux 37 and GE 2340 exhibit an output of 200% or more in extrusion.
To simulate injection molding rheovulcameter measurements were performed. On the left side of the picture you can see the resulting injection-molded pieces. In the table on the right the volumes of the injection-molded pieces are listed according to their values. The reference is set to 100%. Aflux 37, GE 2340 and Rhenofit STA/S have volumes of more than 200%.
Other than the significant reduction in viscosity, most physical properties of the vulcanizates are not affected through the use of Aflux 37, GE 2340 and Rhenofit STA/S.
Nevertheless, these additives can also help shape the tire’s performance. For example, their use reduces energy losses measured according to the Payne effect, and leads to a reduction of tan δ at 60°C, which results in lower rolling resistance.
March 22, 2016