US 4,307,171 A · Negative-working diazo type photoreproduction having improved D-min and line acuity

Abstract

Negative-working diazography material is comprised of (i) at least one hexafluorophosphate diazonium salt adapted to photolytically cleave into an acid catalyst, (ii) at least one acid labile enolic, preferably arylenolic blocked-coupler adapted to be converted in the presence of acid to an active azo-coupling component, and (iii) an effective amount of at least one additive such as benzotriazole, urea, thiourea and derivatives thereof. The additives are believed to react with the acid released during imaging to the extent that migration thereof into the areas which have not been exposed to light is reduced or eliminated. The reduction in the migration of the liberated acid improves the D-min and line acuity of the image obtained from the formulation and the presence of the additive provides a means for decreasing the photo speed of the formulation.

Claims27

Dependent claims

A negative-working light-sensitive diazography formulation comprising (i) at least one light-sensitive hexafluorophosphate salt of a diazonium compound adapted to photolytically cleave into an acid catalyst;

(ii) at least one acid labile arylenolic blocked-coupler adapted to be converted in the presence of acid to an active azo-coupling species;
and (iii) an effective amount of at least one additive selected from the group of compounds represented by the structural formulae:
##STR70## wherein X and Y are selected from the group consisting of hydrogen, chlorine and methyl provided at least X or Y is hydrogen;
and ##STR71## wherein R and R', which can be the same or different, are selected from the group consisting of alkyl of from 1 to about 5 carbons;
hydrogen;
or together constitute a cyclic hydrocarbon group of from about 2 to about 8 carbons;
and X is selected from the group consisting of oxygen and sulfur;
said effective amount being sufficient to improve the line acuity of images obtainable from said formulation.

5 more elements

Dependencies are inferred from the claim text.

Negative-working diazo type photoreproduction having improved D-min and line acuity

Life of this patent

Negative-working diazo type photoreproduction having improved D-min and line acuity

Life of this patent

Abstract

Claims27