Distributive Mixing Characteristics of Batch Internal Mixers

Abstract

Abstract The distributive mixing characteristics of three internal mixers are examined: a Parrel BR Banbury (1.6 L), a Farrel F40 Banbury (40 L), and a Francis Shaw K1 Intermix (5.5 L). The former two machines have two-wing tangential rotors while the latter has intermeshing rotors. The distribution of sulfur in mixed batches of an EPDM compound and an SBR compound, as measured by curemeter tests on samples taken from random locations within each batch, is used to quantify distributive mixing. The dominant influence on sulfur distribution is total rotor revolutions and a maximum of 20 rotor revolutions is adequate for distribution of powder sulfur in each mixer. The effects on distribution of rotor speed, rubber compound rheology, and mixer size are insignificant.