Positive-working radiation-sensitive mixture and copying material produced therefrom comprising an .alpha.-carbonyl-.alpha.-sulfonyl diazomethane, a water-insoluble binder and an acid cleavable compound

A positive-working radiation-sensitive mixture consisting essentially of, in admixture:

• a) a compound which forms an acid on irradiation, in an amount sufficient to cleave compound b),
• b) a compound having at least one C--O--C or C--O--Si bond which can be cleaved by the acid formed by compound a), said mixture comprising an amount of compound b) sufficient to render the mixture soluble or at least swellable in aqueous-alkaline solution when the acid formed from compound a) upon irradiation cleaves compound b), and
• c) a water-insoluble binder which is soluble of at least swellable in aqueous alkaline solutions, said binder being present in an amount sufficient to form a uniform film when a layer of the positive-working radiation-sensitive mixture is coated on a substrate, wherein compound (a) is an .alpha.- carbonyl-.alpha.-sulfonyldiazomethane derivative of the formula I ##STR4## in which R.sup.1 and R.sup.2, independently of one another, denote an alkyl-, cycloalkyl-, aryl- or heteroaryl radical any of which may be optionally-substituted.