Abstract: This invention relates to a radiation-sensitive copying composition which comprises (a) a compound which forms an acid under the influence of actinic radiation, and (b) an organic polymeric compound which contains recurrent acetal or ketal groupings in its main chain and whose solubility in a liquid developer is increased by the action of an acid, each .alpha.-carbon atom of the alcoholic constituent of the acetal or ketal grouping of the organic polymeric compound being aliphatic. The invention also relates to a process for the production of relief images using a radiation-sensitive copying composition.

Abstract: A device for cathodic corrosion protection such as for hot water tanks having a passive anticorrosive layer on the inner wall of the tank. The cathodic corrosion protection employs the use of an external current anode. The device includes a holder which bears the external current anode and a reference electrode. The holder is adapted to be inserted into a single opening in the tank wall. A potentiostat employs the external current anode and reference electrode so as to establish a predetermined potential between reference electrode and the tank by regulating the current flowing through the external current anode to the tank. This provides the desired corrosion protection. Two embodiments of the device are described.

Abstract: This invention relates to an improvement in a light-sensitive copying material, the copying layer of which comprises a water-soluble, curable binder and a diazonium salt polycondensation product of recurring units of the general types (A-N.sub.2 X) and (B) which are linked to one another by intermediate members which have two bonds and are derived from a carbonyl compound capable of undergoing a condensation reaction, wherein A is the radical of a compound which contains at least two isocyclic or heterocyclic aromatic rings and is able to undergo a condensation reaction, at least at one point in the molecule, with formaldehyde in an acid medium, B is the radical of a compound which is free of diazonium groups and is able to undergo a condensation reaction, at least at one point in the molecule, with formaldehyde in an acid medium, and X is the anion of an acid which forms a water-soluble salt with the condensation product, the improvement being that fish glue is the water-soluble, curable binder.

Abstract: This invention relates to a radiation-sensitive copying composition comprising a compound (1) which splits-off an acid upon irradiation and a compound (2) having at least one group selected from the group consisting of a carboxylic ortho acid ester group and a carboxylic acid amide acetal group, which composition, upon irradiation, forms an exposure product having a higher solubility in a liquid developer than the non-irradiated composition.

Abstract: A light-sensitive layer transfer material and such layer disposed on a carrier, for use in screen-printing stencils, printed circuit boards, integrated circuits, intaglio printing plates, relief printing plates, proof prints and the like, which comprises an alkali-soluble phenolic resin, such as phenol-formaldehyde novolacs, an ester or an amide of an o-naphthoquinone-diazide sulphonic acid, such as the p-cumyl phenyl ester of 1,2-naphthoquinone-2-diazide-4-sulphonic acid, etc., and an acrylic resin, such as a polymer of an alkyl ester of acrylic acid or methacrylic acid.

Abstract: This invention relates to a light-sensitive copying composition for the preparation of screen printing stencils comprising a condensation product of an aromatic diazonium compound in admixture with a hydrophilic hardenable binder, the condensation product containing at least one unit each of the general types A(-D).sub.