Carboxylic acid functional polyurethane polymers and blends thereof used in magnetic recording media
AssigneeMinnesota Mining and Manufacturing Company
InventorsJames G. Carlson, Nelson T. Rotto, Jeffrey T. Anderson, Carol-Lynn Spawn, Albena V. Blagev
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Abstract
The invention provides novel macromonomer and carboxyl functional polyurethanes having a high carboxyl content. The invention further provides dispersions, coatings and magnetic recording media comprising these polyurethanes, or blends or copolymers of these polyurethanes with quaternary ammonium compounds. The invention further provides novel dispersions, coatings and magnetic recording media comprising combinations of carboxyl functional polyurethanes having a high carboxyl content with quaternary ammonium polymers.
Claims18
A dispersion comprising:
- (a) one or more of carboxyl polyurethane polymers comprising the reaction product of a mixture comprising:
- (i) one or more polyisocyanates;
- (ii) a carboxylic acid functional polyol(s);
- (iii) optionally one or more polyols, wherein the polyols(s) of element (iii) are defined to exclude components of element(s) (a)(ii);
- wherein the number of isocyanate-reactive groups present in the mixture prior to reaction exceeds the number of isocyanate groups and wherein at least about 0.2 meq of carboxylic acid group are present on the carboxyl polyurethane polymer per gram of carboxyl polyurethane polymer;
- (b) a polymeric quaternary ammonium compound(s) having a number average molecular weight of at least about 500;
- (c) one or more pigments selected from the group consisting of magnetic pigments, non-magnetic pigments, and mixtures thereof;
- and
- (d) an organic solvent;
- and
- (e) optionally a polyisocyanate curative.
A coating comprising a dispersion comprising:
- (a) one or more of carboxyl polyurethane polymers comprising the reaction product of a mixture comprising:
- (i) one or more polyisocyanates:
- (ii) a carboxylic acid functional polyol(s);
- (iii) optionally one or more polyols, wherein the polyols(s) of element (iii) are defined to exclude components of element(s) (a)(ii);
- wherein the number of isocyanate-reactive groups present in the mixture prior to reaction exceeds the number of isocyanate groups and wherein at least about 0.2 meq of carboxylic acid group are present on the carboxyl polyurethane polymer per gram of carboxyl polyurethane polymer,
- (b) a polymeric quaternary ammonium compound(s) having a number average molecular weight of at least about 500;
- (c) one or more pigments selected from the group consisting of magnetic pigments non-magnetic pigments, and mixtures thereof, and
- (d) an organic solvent;
- and
- (e) optionally a polyisocyanate curative, dried of solvent.
Dependencies are inferred from the claim text.