CARBOXYLIC-ACID FUNCTIONAL POLYURETHANE POLYMERS AND THEIR USE IN MAGNETIC RECORDING MEDIA

摘要

The invention provides novel polyurethanes which can be used in magnetic media binders applications. The polyurethanes comprise multidentate chelating functional groups pendant from the polymer backbone, which groups are produced by esterification of backbone hydroxyl moieties with cyclic dicarboxylic acid anhydrides which also bear an additional polar functional group such as those selected from the group consisting of -H, -OH, -COOM, -SO3M, -SH, -CH2COOM, -SCH2COOM, -P(=O)(OM)2, -OP(=O)(OM)2, and the like. Examples of anhydrides useful in preparation of the polyurethanes include anhydrides of citric acid, mercaptosuccinic acid, dimercaptosuccinic acid and nitrilotriacetic acid. The polyurethanes, which are optionally radiation curable, show high affinity for magnetic pigments, and blends of the polyurethanes with vinyl resins afford excellent binders for magnetic recording media.