Patent ID: 6245711
Filing Date: 2001-06-12
Classification: B41M

Abstract:
A thermosensitive recording material comprisingA) a base sheet,B) a thermosensitive coating comprising thermosensitive components on only one surface of said base sheet andC) a latent image on the surface of the base sheet, opposite the thermosensitive coating, wherein said latent image comprisesa) a polymer binder obtained by a U.V., visible light or electron beam initiated free radical cure of at least one monomer and at least one oligomer within a security ink which has a viscosity less than 500 cps at 25.degree. C. and comprises 0-25 wt % of an aqueous based solvent with from 0-1 wt % organic solvent, wherein said monomers and oligomers are free of ketone functional groups, primary or secondary amine functional groups and hydroxy functional groups;b) at least one photoinitiator in an amount eitherless than 10 wt %, based on the weight of the security ink, where said photoinitiator is free of ketone functional groups, primary or secondary amine functional groups and hydroxy functional groups orless than 1 wt %, based on the weight of the security ink, where said photoinitiator contains ketone functional groups, primary or secondary amine functional groups or hydroxy functional groups which degrade the thermosensitive components of the thermosensitive coating;wherein said latent image is waterproof and eitheri) forms a pseudo watermark,ii) additionally comprises a pigment or dye with variable light absorption and/or transmission properties, oriii) provides a combination of i) and ii).