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Abstract

Process for the production of lithographic printing plates comprising (a) providing a lithographic substrate with a hydrophilic surface; (b) applying a negative working radiation-sensitive composition onto the hydrophilic surface, wherein the composition comprises: (i) one or more types of monomers and/or oligomers and/or polymers, each comprising at least one ethylenically unsaturated group accessible to a free-radical polymerization, (ii) at least one sensitizer which in the presence of at least one coinitiator and upon exposure to radiation of a wavelength of 300 to <480 nni or >750 to 1,100 nm initiates the free-radical polymerization of component (i); and (iii) at least one binder with acidic functional groups and is substantially not sensitive to the wavelength range of 480 to 750 nm; (c) image-wise exposure of the resulting negative working lithographic printing plate precursor to radiation selected from the wavelength range of 300 to <480 nm or >750 to 1,100 nm depending on the sensitizer or initiator system used; and (d) removing the non-irradiated areas by means of a treatment with an alkaline developer with a pH value in the range of 9 to 14 comprising (i) water, (ii) one or more alkali hydroxides in an amount sufficient for adjusting a pH value in the range of 9 to 14; and (iii) 1 to 30 wt.-% of at least one compound of formula (I) wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently selected from C.sub.1-C.sub.12 alkyl groups and aryl groups, X is selected from --CH.dbd.CH--, --C.ident.C--, formula (II), formula (III), and formula (IV), n+m results in a value of 2 to 30 and p+q results in a value of 0 to 30, wherein in the case of p+q.noteq.0 the ethylene oxide and propylene oxide units are present as blocks or randomly distributed.

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First Claim