Diazo based imaging element containing hydrolysed polyvinyl alcohol and metal-free phthalocyanine

摘要

The present invention provides an imaging element comprising on a hydrophilic base a light-sensitive layer containing polyvinyl alcohol hydrolyzed to at least an extent of 95% by weight, a cationic surfactant and a diazo resin and/or a diazonium salt characterized in that the light-sensitive layer comprises metal-free phthalocyanine. The present invention also provides a method for obtaining an imaging element as defined in any of the claims 1 to 6 by preparing a dispersion of metal-free phthalocyanine in water in the presence of a cationic surfactant in an amount ranging from 0.24 g/l to 24 g/l; preparing a light-sensitive composition by mixing said dispersion, polyvinyl alcohol hydrolyzed to at least an extent of 95% by weight and a diazo resin and/or a diazonium salt and coating said light-sensitive composition on a hydrophilic base, characterized in that said dispersion comprises polyvinyl alcohol hydrolyzed to at least an extent of 95% by weight in an amount ranging from 4.0 g/l to 200 g/l./!