Abstract: This invention concerns a radiation-curable, magnetic coating material and a magnetic recording medium made with the coating, which is characterized in that a water-soluble or water-dispersed resin having at least one radiation-curable, unsaturated double is contained as a vehicle. The vehicle may also contain a water-soluble or water-dispersible resin, or mixtures thereof free from such an unsaturated double bond. The invention provides a magnetic recording medium with improved durability, softness, flexibility, and heat resistance.

Abstract: This invention provides a magnetic recording medium with excellent electromagnetic characteristics and running durability. According to the invention, a magnetic powder is kneaded with a cross-linkable or polymerizable resin binder, together with a phosphoric ester having a polymerizable, unsaturated double bond or bonds, the resulting coating material is applied to a substrate, and then the coating is cross-linked or polymerized. The addition of the phosphoric ester in place of an ordinary dispersing agent improves the mechanical properties of the magnetic coating and the durability and running quality of the magnetic recording medium.

Abstract: In a magnetic recording medium made by applying a non-magnetic undercoat and a magnetic top coat on a base, the undercoat comprises a radiation-curable coating material which contains a compound with a molecular weight of not less than 400, having one type of double bond selected from among acrylic, allylic, and maleic double bonds, the undercoat being formed by exposure to radiation. Specifically, the undercoating material contains at least two types of compounds selected from (A) those having a molecular weight of over 5000, preferably over 8000 and having two or more double bonds selected as above, (B) those having a molecular weight of 400 or more but less than 500, preferably in the range of 600 to 3000, and two or more double bonds selected as above, and (C) those having a molecular weight of less than 400 and one or more double bonds selected from among acrylic, allylic, maleic, and styrenic double bonds.