Radiation-sensitive composition useful for making lithographic printing plates includes a polyfunctional oxazole, thiazole or selenazole sensitizer and a coinitiator

摘要

Radiation-sensitive composition comprises an ethylenically unsaturated monomer, oligomer or polymer capable of radical polymerization; a polyfunctional oxazole, thiazole or selenazole sensitizer; and a selected coinitiator that forms radicals with the sensitizer. Radiation-sensitive composition comprises an ethylenically unsaturated monomer, oligomer or polymer capable of radical polymerization; a polyfunctional oxazole, thiazole or selenazole sensitizer of formula (I); and a coinitiator that forms radicals with the sensitizer and is selected from metallocenes, 1,3,5-triazine derivatives with 1-3 trichloromethyl or tribromomethyl groups, peroxides, hexaarylbiimidazoles, oxime ethers, oxime esters, N-arylglycines and their derivatives, thiols, N-aryl, S-aryl and O-aryl polycarboxylic acids, onium salts, alkyl triaryl borates, benzoin ethers, benzoin esters, trihalomethyl aryl sulfones, amines, Dialkylaminobenzoate esters, aromatic sulfonyl halides, imides, diazo sulfonates, 9,10-dihydroanthracene derivatives, acylphosphine oxides, diacylphosphine oxides and alpha-hydroxy or alpha-amino acetophenones. X : O, S or Se; m, n, p, q : 0 or positive integers; pi 1, pi 2, pi 3unsaturated units with conjugated pi-electron systems forming a conjugated pi-electron system with the oxazole, thiazole or selenazole rings; R 1>-R 3>H, halo, alkyl, aralkyl, NR 4>R 5> or OR 6>; R 4>-R 6>alkyl, aryl or aralkyl. Independent claims are also included for: (1) radiation-sensitive element comprising a support coated with a composition as above; (2) forming an image on a radiation-sensitive element as above by irradiating the element imagewise with UV radiation of wavelength greater than 300 nm and removing unirradiated regions of the coating with an aqueous alkaline developer; (3) image-bearing element produced as above; (4) producing a radiation-sensitive element by applying a composition as above onto a pretreated supporf and drying the product. [Image].