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

摘要

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 centipoises at 25° C. and 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 aids is unexpectedly good.