Dupont (uk) Limited

Vickers, Inc.

Agfa-gevaert

Afga-gevaert Nv

Michael John Pratt

John R Wade

Rodney M Potts

Jianrong Ren

Allen P Gates

Andrew E Matthews

David E Murray

John Kynaston Davies

Maria De Lurdes Dos Santos Cristiano

Robert Alexander Walker Johnstone

Sharon Dowd

William A King

Robert A Johnstone

Keith M Fletcher

David I Smith

Organic photoprecursors of amines are provided for use in photosensitive imaging systems, finding particular application in the preparation of lithographic printing plates. Said photoprecursors generate free amines on exposure to long wavelength UV or visible radiation, have high solubility in organic solvents, and include photolabile 2-nitrobenzyl functional groups. Methods for the synthesis of the photoprecursors are described, and the use of the said photoprecursors for the production of printing plates using both positive working and negative working techniques are discussed.

Photoactive materials applicable to imaging systems

A radiation sensitive material comprises particles including a water-insoluble heat-softenable core surrounded by a shell which is soluble or swellable in aqueous medium. The material also includes a radiation sensitive component which, on exposure to radiation, causes the solubility characteristics of the material to change. The material may be positive- or negative-working and may be coated onto a substrate from aqueous media to form a radiation sensitive plate which, after image-wise exposure, can be developed in aqueous media and then heated to cause the particles to coalesce and form a durable printing image.

Radiation-sensitive materials

Colorants, polymeric binder resins, photoinitiators, photosensitizers, color-change agents, anti-halation agents, stabilizers, and other active hydrogen-containing components of radiation sensitive compositions for lithographic printing plate production and the like are reacted with a polyethylenically unsaturated monoisocyanate compound of the formula ##STR1## wherein Y is the residue of a monohydroxyl compound of formula YOH and Y contains at least two ethylenically unsaturated double bonds. In this way the components are bonded to the image on exposure.

Photopolymerisable components of radiation sensitive compositions

Radiation-sensitive materials comprising a layer having core-shell

A radiation-sensitive plate comprises a substrate coated with a radiation-sensitive composition including a component having groups imparting solubility in aqueous solutions and a component having functional groups capable of reacting with a silane compound. The surface of the composition is modified by reaction with a silane compound. The plate gives rise to images of improved ink receptivity and can be developed in aqueous developer liquids after image-wise exposure.

Lithographic printing plates containing functional groups capable of

Polyunsaturated diazonium compounds suitable for use in negative working radiation sensitive compositions are provided. They may be produced by reacting an aromatic diazonium compound of the formula

Process for preparing a polyunsaturated diazonium compounds

Polyunsaturated diazonium compounds

A radiation sensitive plate comprises a substrate coated with a photopolymerisable composition. The composition comprises a polymerisable compound containing ethylenic unsaturation, a perester photoinitiator and optionally an optical sensitiser. The substrate may be a sheet of grained and anodised aluminum and the plate is useful in the production of lithographic printing plates.

Radiation sensitive plates

A radiation sensitive plate comprises a substrate coated with a photopolymerizable composition. The composition comprises a polymerizable compound containing ethylenic unsaturation, a perester photoinitiator and optionally an optical sensitiser. The substrate may be a sheet of grained and anodized aluminum and the plate is useful in the production of lithographic printing plates.

Perester compounds suitable for causing the polymerisation of addition polymerisable compounds on exposure to radiation have the general formulae ##STR1##

Perester compounds

Radiation sensitive material suitable for the production of radiation sensitive plates for lithographic printing plate manufacture is based on a polymer including a plurality of structural units represented by the formula: ##STR1## in which, R represents H or CH.sub.3 ; each R.sub.1, which may be the same or different represents H or alkyl; R.sub.2 represents a single bond or a substituted or unsubstituted divalent radical; Ar represents a substituted or unsubstituted divalent radical derived from an aromatic or heteroaromatic compound; X represents O, S or NH; A represents an anion; Y represents a carbonyl oxy or aromatic radical; and n is an integer equal to or greater than 1.

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Ilkley, United Kingdom

Michael John Pratt