POLYMER COLOURING AGENTS, COATING COMPOSITIONS AND THERMOGRAPHIC OFFSET PLATES Russian patent published in 2012 - IPC C09D151/06 B41C1/10 C09B69/10 C09D5/32 B41M5/36 

FIELD: chemistry.

SUBSTANCE: the invention relates to polymer colouring agents used in coating compositions to protect the image forming layer of the offset plates. Described are a new water-soluble polymer colouring agent with the absorption band ranging from about 300 nm to about 600 nm, and a coating composition for a thermographic offset plate which comprises: (a) the said polymer colouring agent with the absorption band ranging from about 300 nm to about 600 nm, and (b) organic microparticles which contain cross-linked copolymers of acrylate ot methylacrylate and styrole, 2-hydroxymethylacrylate, methacrylate, poly(oxyethylene)methacrylate or a linear or branched alkylmethacrylate; or inorganic nanoparticles containing silicone oxide or aluminium oxide. Described is the thermographic offset plate for reverse printing, containing (a) water receptive plate, (b) a layer positioned on the plate which forms the image in the near-infrared region, and (c) the coating layer which is positioned on the image-forming layer and contains the said coating composition.

EFFECT: reduction or elimination of background filling of the offset plates in the conditions of white light, elimination of the need to use separating paper when packaging offset plates.

7 cl, 10 dwg, 13 ex