Method of and an apparatus for finely dividing inelastic materials

Abstract

A method for the fine grinding of inelastic material, in particular polymers as polytetrafluoroethylene, polyethylene, polypropylene, polyamide, organic chemicals and plastic metals, and of materials which are transferred into a state of inelastic behavior before or during grinding by application of heat and/or application and conversion of mechanical energy into heat is disclosed wherein the material to be ground is first urged by compression loading into recesses which are formed in the working face of grinding tools applying the compression loading or pressed into cavities of a bulk of grinding bodies, e.g. balls, preferably after previously mixing the material to be ground with the grinding bodies, the recesses or cavities having a size in accordance with the fineness to be obtained. During or after this procedure residual material which still connects the so formed sub-particles is destroyed by movement of the sub-particles relative to each other. The sub-particles are removed from the recesses or cavities. Apparatuses for carrying out the method are described, among which is a two-roller press the working surface of at least one of its rollers is provided with the recesses the size(s) of which correspond(s) or is related to the size(s) of the sub-particles to be obtained. If a mixture of grinding bodies and material to be ground is to be compressed by a two-roller press the size of the recesses for the formation of compacts, is a multiple of the size of the grinding bodies and the material to be ground. A ram press or a screw or worm press can be used in connection with a mixture of grinding bodies and material to be ground.