E.i. Dupont De Nemours and Company

Robert R Gruetzmacher

Stanley H Munger

Peter F Warfield

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.

Process for preparing an overcoated photopolymer printing plate

Process for providing improved solvent resistant surfaces of relief flexographic printing plates prepared by imagewise exposure and liquid development of the unexposed areas of a layer of a photosensitive elastomeric composition comprising a polymer of a conjugated diolefin hydrocarbon, and a monomeric compound wherein, after drying, the developed surface is in either order (1) postexposed to actinic radiation, and (2) contacted for about 15 seconds to 40 minutes with an aqueous treatment solution of an alkali monopersulfate, e.g., 2KHSO.sub.5.KHSO.sub.4.K.sub.2 SO.sub.4 and a bromide salt, e.g., potassium bromide.

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Chadds Ford, PA, United States of America

Robert R Gruetzmacher