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.

Abstract: A photocurable resin composition comprising a photopolymerizable photosensitizing compound (A) together with or without a photopolymerizable photosensitizing compound (B), the compound (A) being prepared by esterifying with acrylic or methacrylic acid or the like a resin having an OH equivalent of 150 - 500 produced by esterification of a dialkylaminobenzoic acid, a polybasic acid or, if desired, a fatty acid having at least 9 carbon atoms, with a polyhydric alcohol, and the compound (B) being prepared by repeating the aforesaid process for preparing the compound (A) except that a carboxyl group-containing benzophenone derivative is substituted for the dialkylaminobenzoic acid.

Abstract: Ultraviolet light curable coating compositions comprising (1) a monomer and/or prepolymer containing at least one radically crosslinkable ethylenically unsaturated double bond and (2) a photopolymerization initiator containing (a) 4,4'-bis(diethylamino)benzophenone and (b) a lower alkyl ester of p- or o-benzoylbenzoic acid or a derivative thereof in a weight ratio of (a) to (b) of 1 : 1 to 1 : 10.

Abstract: A photosensitive coating composition comprising (1) a prepolymer containing radically cross-linkable ethylenically unsaturated double bonds and (2) a sensitizer which comprises predominantly a mixture of (a) benzophenone, halogenated benzophenone or a combination thereof and (b) 4,4'-bis(diethylamino)benzophenone in a weight ratio of about 1:2 to 10:1.