Stable, pumpable, solvent-free polyampholyte latices, their preparation and use in paper

Abstract From the Canadian patent

Stable, pumpable solvent-free polyampholyte latices characterized by their colloidal nature as well as by a solids content of about 10 to 40% by weight and a RVF Brookfield bulk viscosity of up to 20,000 cps at 25°C 20 RPM are, prepared by polymerizing 10-30 mole % of a cationic monomer 5-30 mole, % of an anionic monomer, 15-35 mole % of a hydrophobic monomer and, 5-70 mole % of a non-ionic hydrophilic monomer. The monomer amounts are selected so as to provide a copolymer having a charge density of about 15 to 60 mole % and charge ratio of between about 0.33 and 6. The polymerization is carried out without the use of solvents. The performance of the latices as pigment retention and drainage …