Amphoteric latexes containing pH independent and pH dependent bound charges
AssigneeThe Dow Chemical Company
InventorsDale M. Pickelman, Larry D. Yats
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Abstract
A selectively stable latex has discrete polymer particles which have present as bound charges both a pH independent charge (such as sulfonium) and a pH dependent charge of opposite polarity of the pH independent charge (such as carboxyl), wherein the two charges are present in such proportion that the latex is stable in at least one pH range and controllably unstable in at least one pH range. The latexes of the invention are extremely useful in the preparation of fibrous composites such as highly-filled composite paper and fine printing paper.
Claims7
A selectively stable latex comprising discrete polymer particles which have present as bound charges both
- (a) a pH independent charge present at a charge density of about 0.8 to about 0.4 meq/g;
- and
- (b) a pH dependent charge, of opposite polarity of the pH independent charge;
- wherein the two charges are provided by an addition polymerizable monomer and are present in such proportion that the net charge density is about 0.02 to about 0.2 meq/g and the latex is stable in at least one pH range and controllably unstable in at least one pH range.
Dependencies are inferred from the claim text.