Method of producing milling adjuvants and/or dispersive agents, by physicochemical separation; adjuvants and agents thus obtained; and uses of same

A method of producing a milling adjuvant or dispersing agent, comprising:

• a) introducing a water-soluble separand material into a separation apparatus having one or more organic or mineral membranes, said membrane being optionally borne on a support;
• and
• b) separating the water-soluble separand material into a plurality of permeate and retentate phases containing different molecular weight fractions of said separand material, by differences therebetween in hydrodynamic volume in a continuous or batch process;
• wherein at least one of said retentate contains said milling adjuvant or dispersing agent;
• wherein said water-soluble separand material is selected from the group consisting of a vinyl polymer, vinyl copolymer, acrylic polymer, acrylic copolymer, polycondensate polymer and polycondensate copolymer;
• wherein said water soluble separand material has at least one acidic functional group, and is either partially or completely neutralized by means of a neutralizing agent;
• and
• further wherein said milling adjuvant or dispersing agent obtained exhibits a molecular weight distribution curve obtained by aqueous gel permeation chromatography with refractometric detection, wherein, a second infection pick in said curve, corresponding to a shoulder, has an attenuation of at least 3% based on the introduced water-soluble separand material, irrespective of a dry matter content of the water-soluble separand material introduced into the separation apparatus.