| abstract |
The present invention relates to sulfonated, thiol and hydroxy functional polyurethane polymers consisting of (i) to (iv): (i) a polyurethane backbone; (ii) at least one SO 3 M group suspended in the polyurethane backbone, which has a SO 3 M equivalent of about 2,000 to about 100,000, wherein M is H + , NR 4 + , where R is H or an alkyl group Li + , Na + , K + , and mixtures thereof); (iii) at least two crosslinkable hydroxy groups suspended in the polyurethane backbone (the polyurethane backbone has a hydroxy equivalent weight of about 500 to about 50,000); And (iv) at least one SH group suspended in the polyurethane backbone. The present invention also relates to vinyl / polyurethane copolymers which are particularly useful as binders for magnetic recording media and methods for their preparation. The present invention also relates to unsulfonated liol and hydroxy functional polyurethane graft copolymers and dispersions prepared therefrom. |