Abstract
Fluctuation of torque just after feeding natural rubber (NR) blocks into an oval-type twin-rotor mixer is discussed. A wedge-type model mixer was designed specially to simulate breaking behavior of NR between rotor and chamber. NR blocks of various thicknesses were contorted and finally broken in the model mixer. Two types of breaking phenomena were observed. One was instantaneous breaking of relatively thick blocks. The other was intermittent breaking of relatively thin blocks. These phenomena were mainly associated with the elastic deformation of the material. By considering these two types of breaking, the torque fluctuation measured during operation of the mixer was analyzed. It was clarified that the first peak of torque was originated from the first breaking of the block in the thickest state.
