Hydrophilic ampholytic polymer

A hydroplilic ampholytic copolymer which is compatible with both anionic and cationic materials, the copolymer being formed by copolymerizing:

• 0.05 to 20 mol percent of an anionic monomer;
• 10 to 45 mol percent of a non-quaternized cationic monomer;
• 35 to 95 mol percent of a non-ionic hydrophilic monomer in a sufficient quantity to provide the copolymer with a glass transition temperature of above about 50° C.;
• 0.5 to 10 mol percent of a hydrophobic monomer;
• and,
• 0 to 1.5 mol percent of a cross-linking monomer.

A method of preparing a hydrophilic ampholytic polymeric copolymer comprising copolymerizing:

• 0.05 to 20 mol percent of an anionic monomer having at least one carboxy-functional group;
• 10 to 45 mol percent of a non-quaternized cationic monomer having at least one amino-functional group;
• 45 to 90 mol percent of a non-ionic hydrophilic monomer;
• 0.5 to 10 mol percent of a hydrophobic monomer;
• and
• 0 to 1.5 mol percent of a cross-linking monomer,
• wherein the monomers are selected so as to provide the copolymer with a glass transition temperature of above about 50° C. and the non-quaternized cationic monomer to the anionic monomer ratio is from about 2:1 to about 16:1.