Patent ID: 6132617
Filing Date: 2000-10-17
Classification: C01P,C08F,C09C,C09D,C09K,E21B

Abstract:
A milling adjuvant or dispersing agent, produced by a process, comprising:a) introducing a water-soluble separand material in an aqueous medium into a separation apparatus having one or more organic or mineral membranes, said one or more membranes being optionally borne on a support; andb) 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 phases is a retentate phase and 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;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 inflection peak in said curve, corresponding to a shoulder, has an of attenuation of 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;and wherein said acidic functional group of said water-soluble separand material is partially-, fully neutralized or unneutralized.