Process for preparing an overcoated photopolymer printing plate
First Claim
1. In a process for preparing flexographic photopolymerizable elements which comprises passing into the nip of a calender a mass of a hot photopolymerizable composition comprising an elastomeric binder, an ethylenically unsaturated compound having at least one terminal ethylenic group, and a photoinitiator or photoinitiator system, and, while hot, calendering the photopolymerizable composition between a support and a multilayer cover element to form a photopolymerizable layer therebetween, the improvement wherein the multilayer cover element consists essentially of a flexible cover film and a layer of an elastomeric composition and optionally between the flexible cover film and the layer of elastomeric composition a flexible polymeric film, the layer of elastomeric composition being adjacent to the photopolymerizable layer and being photosensitive or becoming photosensitive during or after calendering by contact with the photopolymerizable layer, said layer of elastomeric composition comprising an elastomeric polymeric binder and optionally a second polymeric binder and a nonmigratory dye or pigment and, in addition, when said layer of elastomeric composition is photosensitive one or more ethylenically unsaturated monomeric compounds and/or photoinitiator or initiator system.
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Abstract
Process for preparing flexographic photopolymer elements by passing into the nip of a calender a photopolymer composition mass comprising elastomeric binder, monomeric compound, and photoinitiator and calendering the photopolymer composition either between (1) a support and multilayer cover element consisting essentially of a flexible cover film, optionally a flexible polymeric film, e.g., polyamide, and a layer of elastomeric composition which is photosensitive or becomes photosensitive during or after calendering, or between (2) two supports, one of which is removed prior to contact, e.g., by lamination or pressing, with the multilayer cover element. The flexographic photopolymer elements are useful for flexographic printing, e.g., dry-offset, letterpress printing.
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Citations
18 Claims
- 1. In a process for preparing flexographic photopolymerizable elements which comprises passing into the nip of a calender a mass of a hot photopolymerizable composition comprising an elastomeric binder, an ethylenically unsaturated compound having at least one terminal ethylenic group, and a photoinitiator or photoinitiator system, and, while hot, calendering the photopolymerizable composition between a support and a multilayer cover element to form a photopolymerizable layer therebetween, the improvement wherein the multilayer cover element consists essentially of a flexible cover film and a layer of an elastomeric composition and optionally between the flexible cover film and the layer of elastomeric composition a flexible polymeric film, the layer of elastomeric composition being adjacent to the photopolymerizable layer and being photosensitive or becoming photosensitive during or after calendering by contact with the photopolymerizable layer, said layer of elastomeric composition comprising an elastomeric polymeric binder and optionally a second polymeric binder and a nonmigratory dye or pigment and, in addition, when said layer of elastomeric composition is photosensitive one or more ethylenically unsaturated monomeric compounds and/or photoinitiator or initiator system.
Specification