Stable diazo material developable by heat, steam or water - with developer system layer contg. guanidine or bi:guanide deriv. salt of volatile acid over photosensitive layer

摘要

Heliographic prod. developable by heat, steam or water, comprises a developer system contained in a layer superposed on the photosensitive layer and contg. at least one substd. guanidine or biguanide deriv. partially converted to salt form with one or more volatile acids, or a mixt. of these salts with a salt of a volatile acid and an amino-alcohol, an amino-diol or an aminotrial, together with development accelerators. The photosensitive layer may contain salts which raise the pH when mixed with the products in the first layer during development, but also serving as repellents which reduce the penetration of the upper layer into the lower layer during its application. The guanidine and biguanide salts are insol. in the organic solvents used to make the coating solns. so that storage diazotype materials can be made. The salts remain neutral during storage but rapidly release alkaline substances on the application of heat, steam or water during development. They have low hygroscopicity at ambient temp. so that the materials are not sensitive to atmospheric moisture during storage.