an apparatus is disclosed for comminuting a colored pigment bar and mixing the comminuted pigment with an uncolored plastic material to form a colored plastic material which is subsequently molded or extruded into a colored plastic article . the apparatus features a rotating , discontinuous cutting blade to minimize static electricity formation so as to allow more thorough mixing of the pigment with the uncolored material . a storage mechanism is also disclosed to store the colored pigment bars and bring them into contact with the cutting blade .