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AssigneeNational Starch and Chemical Corporation
InventorsCarmine P. Iovine, Dilip K. Ray-Chaudhuri
Estimating the term…
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.degree. 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.
A stable, pumpable, solvent-free polyampholyte latex, characterized 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.degree. C. and 20 RPM, which comprises water and an amphoteric copolymer colloidally dispersed therein, said copolymer characterized by a charge density of 15 to 60 mole % and a cationic to anionic molar charge ratio between about 0.33 and 6 and derived from:
A stable, pumpable, solvent-free polyampholyte latex comprising water and an amphoteric copolymer colloidally dispersed therein, said latex characterized 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.degree. C. and at 20 RPM and said copolymer characterized by a total charge density of about 15 to 60 mole % and a cationic to anionic molar charge ratio between about 0.33 and 6, said latex prepared by a process comprising the step of polymerizing at 30.degree. to 100.degree. C., in the presence of water and a free radical initiator and optionally a chelating agent, about 10 to 30 mole % of at least one cationic monomer, about 5 to 30 mole % of at least one anionic monomer, about 15 to 35 mole % of at least one hydrophobic monomer, and about 5 to 70 mole % of at least one non-ionic hydrophilic monomer, said monomer percentages totaling 100 mole %.
In a method for making paper, the step which comprises adding, as a paper-making aid, to the paper-making pulp at any stage prior to forming a web, a stable, pumpable, solvent-free polyampholyte latex characterized, before any optional dilution thereof, 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.degree. C. and 20 RPM, said latex comprising water and an amphoteric copolymer colloidally dispersed therein, said copolymer characterized by a total charge density of 15 to 60 mole % and a cationic to anionic molar charge ratio between about 0.33 and 6 and derived from at least one cationic monomer present in a total amount from about 10 to 30 mole %, at least one anionic monomer present in a total amount from about 5 to 30 mole %, at least one hydrophobic monomer present in a total amount from about 15 to 35 mole %, and at least one non-ionic hydrophilic monomer present in a total amount from about 5 to 70 mole %, said monomer percentages totaling 100 mole %;
Dependencies are inferred from the claim text.