Imperial Metal & Chemical Company

E.i. Dupont De Nemours and Company

Witco Chemical Corporation

Richardson Graphics Company

Luigi Amariti

Llandro C Santos

Carl Bernstein

Konstantinos Arvanitis

A developer is disclosed for lithographic printing elements. The developer is single phase and contains an aliphatic cyclic carbonate, water, and optional ingredients.

Single-phase developers for lithograpic printing elements

Emulsion developers for diazo-sensitized printing plates are disclosed which are characterized by an oil phase containing a partially water-soluble aliphatic cyclic carbonate having the formula: ##STR1## where n is an integar from 0-2, and Z is selected from hydrogen, C.sub.1 -C.sub.3 alkyl, hydroxyl alkyl or chloroalkyl, chlorine, hydroxy or phenyl. The preferred carbonate is propylene carbonate.

Developer including an aliphatic cyclic carbonate in the oil phase

Photopolymeric polyurethanes are provided which have a polymeric backbone including recurring urethane or urea groups or both and which have unsaturated hydrocarbon groups attached to this backbone. These photopolymers are combined with a solvent and have a selected and controlled molecular weight and viscosity. The photopolymeric polyurethane solutions are especially useful in providing plates that have a layer including a photopolymer, particularly plates for printing or photoresists that have a photopolymeric layer over a layer of light sensitive diazonium composition.

Photosensitive plates with diazonium composition layer and polyurethane

A developer is provided for lithographic plates or the like having a layer including a diazonium material, which developer enhances the effectiveness of the photolysis to which the plate had been subjected, with the result that the exposure time needed for the plate is substantially reduced. The developer, which thus enhances the apparent photospeed of the plate, includes an insolubilizing reactant that reacts with diazonium groups of diazonium materials on the plate that were not removed by photolysis during exposure in order to decrease the solubility of the diazonium material.

Method for enhancing apparent photospeed of diazonium plates by using

Plates such as those used in lithographic printing and photoresists such as those used in preparing printed circuit boards and the like are provided with a photopolymerizable photosensitive diazo resin that is unusually stable. The diazo resin is laid down from a stabilized diazonium composition that is an emulsion including the selected diazo resin, a purine derivative, especially a theophylline derivative, preferably in combination with a salt of a low molecular weight alkyl sulfonic acid or other supplementary stabilizer component.

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Bloomingdale, IL, United States of America

Luigi Amariti