Abstract: The invention relates to a recording material for the production of offset printing plates, having a web- or plate-form support, a radiation-sensitive layer on the front of the support and a continuous, pigment particle-free layer on the back of the support. The back layer essentially consists of an organic polymeric material having a glass transition temperature Tg of at least 45° C., and its surface has a Bekk smoothness of from 5 to 800 s. It also relates to a process for the production of this recording material.

Abstract: The invention relates to a dummy plate for offset printing which essentially consists of a plate, foil or band-shaped, mechanically cally and/or electrochemically roughened, anodically oxidized and hydrophilized aluminium support and a non-light-sensitive, water-soluble layer applied thereto, where the layer comprises at least one copolymer which has monomer units having pendant groups of the formulae —CO—NH— and/or —CO—N< and whose solubility in water at a temperature of 25° C. is at least 50 g/l, and at least one acidic compound and/or a salt thereof. Due to the coating, the surface remains permanently hydrophilic. The dummy plate can be used in the printing machine without pretreatment. During printing, the layer is completely removed by the fountain solution after a short time without the paper web and the rubber blanket cylinder sticking to one another during proof printing.

Abstract: The invention relates to a recording material for the production of offset printing plates, having a web- or plate-form support, a radiation-sensitive layer on the front of the support and a continuous, pigment particle-free layer on the back of the support. The back layer essentially consists of an organic polymeric material having a glass transition temperature Tg of at least 45° C., and its surface has a Bekk smoothness of from 5 to 800 s. It also relates to a process for the production of this recording material.

Abstract: A positive-working, radiation-sensitive mixture which contains an organic, polymeric binder which is insoluble in water but soluble or at least swellable in aqueous alkaline solution and at least one IR-absorbing dye, is described. A daylight-insensitive recording material which can be provided with an image using IR radiation and has a substrate and a layer comprising the mixture is also disclosed. After imagewise exposure, in particular to IR laser beams, and development with an aqueous alkaline solution, an offset printing plate can be formed therefrom.

Abstract: This invention relates to a process for preparing printing plates which are used in offset printing. The process produces a plate which comprises a substrate film in which a thin durable hydrophilic layer has been applied thereto. In the process, the substrate film is first microroughened by pressure blasting so that the surface roughness, R.sub.A, is in the range 0.3 to 1.5 .mu.m. Subsequently, a durable, firmly adhering hydrophilic layer is applied to substrate by plasma-spraying an oxide powder with a particle size of 1 to 40 .mu.m onto the substrate. This process produces a plate whose surface is not greasy or grainy.

Abstract: A support material for photosensitive substances, useful in the production of offset-printing plates, is disclosed. The support material comprises mechanically, chemically or electrochemically roughened aluminum or an aluminum alloy in the form of a sheet, a foil or a web, and which is coated on at least one side with a hydrophilic polymer which comprises (a) at least 2 mol% of units having acidic side groups and (b) at least 2 mol% of units having basic side groups which are capable of being protonated.

Abstract: The invention relates to a hydrophilic copolymer having the general structure:. . . --(A).sub.m -- . . . --(B).sub.n -- . . . --(C).sub.o -- . . . --(D).sub.p -- . . .in whichA is at least one polymerizable monomer having an acidic side group,B is at least one polymerizable monomer having a basic side group,C is at least one polymerizable monomer having a non-polar, non-hydrophilic side group, andD is at least one polymerizable monomer capable of increasing the hydrophilic character of monomer A or to form a chelate with monomer A,m, n, o and p are the monomer contents of monomers A, B, C and D, respectively, in mol %, with m+n+o+p=100 mol %, with the proviso that m and n are each.gtoreq.2 mol % and p is .gtoreq.1 mol %,wherein the copolymer is a linear copolymer having a random structure of the monomers. The copolymer is useful as a hydrophilizing agent for lithographic and offset printing plates, and as a binder in light-sensitive lithographic layers.

Abstract: The invention relates to a hydrophilic copolymer having the general structure: ##STR1## in which R.sup.1 denotes H, CH.sub.3 or C.sub.2 H.sub.5,R.sup.2 denotes an alkyl or cycloalkyl radical having 1 to 17 carbon atoms,R.sup.3 denotes CH.sub.3, C.sub.2 H.sub.5 or C.sub.3 H.sub.7,m is 2, 3 or 4 andn, o, p denote the fractions of the monomer units having acidic side groups, neutral, non-ionizable monomer units and monomer units having basic side groups respectively, in mol %, with n+o+p =100 mol %, with the proviso that n and p are each .gtoreq.5 mol %,wherein the copolymer is a linear copolymer having a random structure of monomer units. The copolymer is useful as a hydrophilizing agent for lithographic and offset printing plates.

Abstract: The invention relates to a thermally crosslinkable hydrophilic copolymer have the general structure:. . . --(A).sub.m --. . . --(B).sub.n --. . . --(C).sub.o --. . . --(D).sub.p --. . .in whichA is at least one polymerizable monomer having an acidic side group,B is at least one polymerizable monomer having a basic side group,C is at least one polymerizable monomer having a non-polar, non-hydrophilic side group, andD is N-butoxymethylmethacrylamide,m, n, o and p are the monomer contents of monomers A, B, C and D, respectively, in mol %, with m+n +o+p=100 mol %, with the proviso that the sum of m+n=about 5 to 90 mol %, m and n are each .gtoreq.2 mol % and p is .gtoreq.1 mol %,wherein the copolymer is a linear copolymer having a random structure of the monomers. The copolymer is useful as a hydrophilizing agent for lithographic and offset printing plates.

Abstract: The invention relates to a hydrophilic copolymer having the general structure: ##STR1## in which R.sup.1 denotes H, CH.sub.3 or C.sub.2 H.sub.5,R.sup.2 denotes an alkyl or cycloalkyl radical having 1 to 17 carbon atoms,R.sup.3 denotes CH.sub.3, C.sub.2 H.sub.5 or C.sub.3 H.sub.7,m is 2, 3 or 4 andn, o, p denote the fractions of the monomer units having acidic side groups, neutral, non-ionizable monomer units and monomer units having basic side groups respectively, in mol %, with n+o+p=100 mol %, with the proviso that n and p are each .gtoreq.2 mol %,wherein the copolymer is a linear copolymer having a random structure of monomer units. The copolymer is useful as a hydrophilizing agent for lithographic and offset printing plates.

Abstract: A process for roughening aluminum or alloys thereof for printing plate supports, wherein an electrochemical roughening is performed by means of alternating current in an acidic electrolyte including sulfate ions and chloride ions, the chloride ions being in the form of aluminum chloride. In a preceding or subsequent rougheniong stage, mechanical roughening and/or electrochemical roughening by means of alternating current in an electrolyte is carried out. The electrolyte can include hydrochloric acid and aluminum ions, nitric acid and aluminum ions or sulfuric acid and chloride ions.

Abstract: A process is disclosed for the electrochemical roughening of aluminum for use in printing plate supports, which is carried out by means of an electrolyte containing sulfate ions and aluminum chloride; preference is given to sulfuric acid and aluminum chloride. Printing plate supports roughened by the process according to the present invention show a particularly uniform, pit-free and overall roughening structure.

Abstract: This invention relates to a single-stage process for imaging an electrically conductive substrate by the action of electric current, wherein the substrate is brought into contact with an electrically conductive solution of an organic substance, a direct voltage is applied between the substrate and at least one electrode, and the organic substance is deposited imagewise by current impulses, at a current density from 0.01 to 100 A/dm.sup.2. The organic substances used preferably comprise polymers.

Abstract: A process is disclosed for the selective additive correction of voids in copying layers, in which electrically conductive aqueous solutions of an organic compound are deposited in the void, with direct current connection between conductive substrate and at least one electrode, and with a current density in the range from 0.01 to 100 A/dm.sup.2. The process is preferably carried out using organic polymers with substrates composed of metal, for example, aluminum, in grained and anodized form.

Abstract: A process in disclosed for the multiple graining of aluminum or aluminum alloys for use in printing plate supports. In the process, mechanical graining is followed by graining with a direct current in a nitrate-containing electrolyte. Optionally, the graining is followed by an anodizing treatment.

Abstract: A process for electrochemically modifying support materials of aluminum or aluminum alloys, which have been grained in a multi-stage process is disclosed. These support materials can be used in the production of offset printing plates. The support material is mechanically grained in a stage I, subjected to an intermediate treatment in a stage II, electrochemically grained in a stage III, subjected to an intermediate treatment in a stage IV and anodically oxidized in a stage V. The intermediate treatment in stages II and/or IV are carried out by an electrochemical process using a direct current. The anodizing stage may be followed by a hydrophilizing stage VI.

Abstract: In a process for reducing halations during the imagewise irradiation of a reproduction layer exposed through a planar image original, at least one lubricant either is contained in the layer or is interposed between the layer and the image original. Suitable lubricants include organic polysiloxanes, hydrocarbon polymers, polyaryl esters, and alkanoic acids or alkenoic acids having at least 9 carbon atoms. Excluded are lubricants comprising copolymers of dimethyl dichlorosilane, ethylene oxide and propylene oxide, provided they are located in the reproduction layer.

Abstract: Printing forms or metallized images can be prepared electrophotographically by a process comprising the electrostatic chargeup, imagewise exposure and tonering of a photoconductor layer applied to an electroconductive base material, followed by fixing of the tonered image areas, removal of the photoconductive layer in the non-image areas by decoating and, where appropriate, etching of the bared base material surface. A recording material is used that comprises a photoconductive layer containing at least one organic n-conducting pigment in a concentration between 10 and 50 percent by weight and an organic p-conducting photoconductor in a concentration of 0 to 20 percent by weight, based on the layer weight, together with a binder which is soluble or dispersible in aqueous-alkaline solution. The decoating is carried out with an aqueous-alkaline decoater solution, which preferably contains alkali metal hydroxides and/or phosphates.

Abstract: The present invention relates to a process for the electrochemical graining of aluminum or aluminum alloys useful for printing plate supports, in which process an acid electrolyte containing .beta.-diketo compounds is employed; preferred are hydrochloric or nitric acid with an acetylacetone admixture. The printing plate supports grained by the process possess a particularly uniform, pit-free and overall graining structure.

Abstract: Disclosed is a process for the electrochemical roughening of aluminum or aluminum alloys useful for printing plate supports, in which an electrolyte containing chloride ions and ammonium ions, preferably hydrochloric acid and ammonium chloride, respectively, is employed. Also disclosed is a printing plate support roughened by the above process which possesses a particularly uniform graining structure.