Mixing and shearing roller-mill

A mixing and shearing roller-mill for plasticisable material comprising first and second rotatable, tempered rolls, each said roll defining a longitudinal axis, said rotation being effected about said longitudinal axis, drive means for each said roll for rotating said rolls at different speeds relative to one another, each said roll having an axial length and a diameter, said axial length being at least four times greater than said diameter, each said roll including an external surface, said external surface defining grooved portions, the transition regions between said surface and each said groove being sharp-edged, each said groove being inclinedly disposed at an acute angle relative to said roll axis, said grooves on said first roll having an opposite hand to said grooves on said second roll, each said roll defining first and second axial end regions and a central region intermediate said end regions, said material feed means disposed in said first end region and material discharge means disposed in said second end region, the number and depth of said grooves increasing from said first end region to said central region and decreasing from said central region to said second end region, said rolls jointly defining a roll nip therebetween and adjustable feed and discharge means for feeding and discharging different types of material and additives axially disposed along said roll nip.