Carboxylic acid functional polyurethane polymers and blends thereof used in magnetic recording media
AssigneeImation Corp.
InventorsJames G. Carlson, Jeffrey T. Anderson, Ramesh C. Kumar, Alvin M. Berg
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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 magnetic recording medium comprising:
- (a) a substrate, and
- (b) a coating on at least one side of the substrate comprising:
- (1) a carboxyl polyurethane polymer comprising the reaction product of a mixture including:
- (A) a polyisocyanate, and
- (B) a mono-carboxylic acid functional polyol, wherein the carboxylic acid functional group is directly bonded to the backbone of the polyol though a carbon-carbon bond
- (C) wherein the number of isocyanate-reactive groups present in the mixture prior to reaction exceeds the number of isocyanate groups, and greater than 0.2 meq of the carboxylic acid groups are present on the carboxyl polyurethane polymer per gram of carboxyl polyurethane polymer,
- (2) a nonhalogenated vinyl copolymer including:
- (A) 5 to 40 parts by weight (meth)acrylonitrile,
- (B) 30 to 80 parts by weight nonhalogenated, nondispersing, vinyl monomer,
- (C) 5 to 30 parts by weight nonhalogenated, hydroxy functional, vinyl monomer, and
- (D) 0.25 to 10 parts by weight of a nonhalogenated, vinyl monomer bearing a dispersing group, and
- (3) a pigment.
A magnetic recording medium comprising:
- (a) a substrate, and
- (b) a coating on at least one side of the substrate comprising:
- (1) a carboxyl polyurethane polymer comprising the reaction product of a mixture including:
- (A) a polyisocyanate, and
- (B) a mono-carboxylic acid functional polyol, wherein the carboxylic acid functional group is directly bonded to the backbone of the polyol though a carbon-carbon bond
- (C) wherein the number of isocyanate-reactive groups present in the mixture prior to reaction exceeds the number of isocyanate groups, and greater than 0.2 meq of the carboxylic acid groups are present on the carboxyl polyurethane polymer per gram of carboxyl polyurethane polymer,
- (2) a nonhalogenated vinyl copolymer including:
- (A) 5 to 40 parts by weight (meth)acrylonitrile,
- (B) 30 to 80 parts by weight nonhalogenated, nondispersing, vinyl monomer,
- (C) at least 1 to less than 5 parts by weight nonhalogenated, hydroxy, functional, vinyl monomer, and
- (D) 0.25 to 10 parts by weight of a nonhalogenated, vinyl monomer bearing a dispersing group, and
- (3) a pigment.
Dependencies are inferred from the claim text.