Abstract: A process for the production of a photosensitive recording material for producing relief printing plates is described, in which a photosensitive layer is laminated with a composite element comprising a protective cover sheet, a release layer and, if required, a further layer, wherein the surface of the uppermost layer of the composite element or the surface of the photosensitive layer is subjected to a corona treatment immediately before contact. As a result of the corona treatment, the adhesion of the applied layer is substantially increased.

Abstract: Flexible printing plates are produced from printing plates consisting essentially of a dimensionally stable substrate (1) and a recording layer (2) by a process in which the printing plate is produced alternatively either by photochemical or by mechanical structuring, and in the case of photochemical structuring the photosensitive recording layer (2) is exposed imagewise and the unexposed parts of the recording layer (2) are washed out with a developer and in the case of mechanical structuring the originally photosensitive, uniformly exposed recording layer (2) is cut imagewise and the nonprinting parts of the recording layer (2) are peeled off from the substrate (1).The printing plates produced by this process are suitable for the production of products printed by the flexographic method and for lacquering products printed by the offset method.

Abstract: Flexible printing plates are produced from printing plates consisting essentially of a dimensionally stable substrate (1) and a recording layer (2) by a process in which the printing plate is produced alternatively either by photochemical or by mechanical structuring, and in the case of photochemical structuring the photosensitive recording layer (2) is exposed imagewise and the unexposed parts of the recording layer (2) are washed out with a developer and in the case of mechanical structuring the originally photosensitive, uniformly exposed recording layer (2) is cut imagewise and the nonprinting parts of the recording layer (2) are peeled off from the substrate (1).The printing plates produced by this process are suitable for the production of products printed by the flexographic method and for lacquering products printed by the offset method.

Abstract: A novel, improved continuous process for the production of a photosensitive recording element is described, whose photopolymerizable recording layer (A) consists of two or more individual strata (a.sub.n) lying one on top of the other and firmly bonded to one another. The individual strata (a.sub.n) may be of the same or roughly the same composition or of different compositions. In the novel, improved continuous process, the mixtures (a.sub.n) used for the production of the individual strate (a.sub.n) are prepared separately from one another and melted and, as separate molten material streams (a.sub.n), are combined even before entering the nip of a calender, without the said streams mixing as a result of turbulence. During, before or directly after they have been combined, the molten material streams (a.sub.n) are formed into molten sheet-like structures (a.sub.n) lying one on top of the other, without the said streams mixing as a result of turbulence. Thereafter, the molten sheet-like structures (a.sub.

Abstract: A light-sensitive recording element useful for preparing photopolymer flexographic relief printing plates, comprising at least one photopolymerizable recording layer having a thickness of from 0.1 to 7 mm and made up of:from 20 to 99.499% by weight of at least one polymeric binder which may be random ethylene-propylene-alkadiene terpolymers having an ethylene content of from 40 to 80% by weight and a double bond content of from 2 to 20 olefinic double bonds per 1,000 carbon atoms;from 0.001 to 10% by weight of at least one photopolymerization initiator,from 0.5 to 50% by weight of at least one monomer which is compatible with the binder and has at least one photopolymerizable olefinic double bond, andfrom 0.001 to 2% by weight of at least one inhibitor of thermally initiated polymerization and from 0.0001 to 5% by weight of at least one antioxidant as assistants.

Abstract: Multilayer, photosensitive recording materials which can be developed with aqueous media contain one or more layers of a mixture which is crosslinkable by photopolymerization, soluble or dispersible in aqueous media and based on polymer containing hydroxyl and/or amide groups, as binders, compatible photopolymerizable monomers and photopolymerization initiators, which mixture contains from 0.1 to 10% by weight, based on its total amount, of an aldehyde of the general formula I ##STR1## where R is hydrogen, hydroxyl, C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.6 -alkoxy, C.sub.6 -C.sub.10 -aryl or C.sub.6 -C.sub.10 -aryloxy.

Abstract: Photopolymerizable laminates suitable for producing printing plates have on a dimensionally stable base at least one intermediate layer and on top thereof a photopolymerizable relief-forming layer, the intermediate layer containing aryl glycidyl (meth)acrylate in an at least partially polymerized state.

Abstract: A photosensitive recording material for the production of printing plates, relief plates or resist images comprises a photocurable relief-forming layer (RL) which is applied onto a dimensionally stable base and consists of(a) a water-soluble or water-dispersible polyvinyl alcohol derivative containing from 1 to 12 mole % of olefinically unsaturated photopolymerizable or photocrosslinkable side groups, in particular of .alpha.,.beta.-olefinically unsaturated carboxylic acids, not more than 30 mole % of hydroxyl groups which are esterified and/or etherified with other non-olefinic radicals, and not less than 65 mole % of free hydroxyl groups and(b) one or more photopolymerization initiators, with or without(c) conventional non-photopolymerizable assistants and/or additives.

Abstract: A sheet-like structure is produced from a vinyl alcohol polymer by a method wherein, in a self-cleaning multi-screw extruder, the polymer is mixed with a small amount of water, the mixture is melted, homogenized, devolatilized and finally extruded as a melt, and the extrudate is shaped in a conventional manner into the sheet-like structure.

Abstract: Multi-layer photopolymer elements, which are suitable for the production of relief printing plates and contain photosensitive polyvinyl alcohol/monomer layers which can be developed with water, can be improved in respect of their production, drying and shelf life by the application of a thin layer of a highly hydrolyzed low molecular weight polyvinyl alcohol.

Abstract: Photopolymerizable compositions for the manufacture of relief printing plates, especially relief plates for making mats, comprising an alcohol-soluble linear polyamide, a photoinitiator and a mixture of (a) a diether or triether obtained from 1 mole of an aliphatic diol or triol and from 2 to 3 moles of N-hydroxymethylacrylamide or N-hydroxymethylmethacrylamide and (b) an unsaturated ester-urethane obtained from 1 mole of toluylene diisocyanate and 2 moles of a hydroxyalkyl acrylate or methacrylate, (a) and (b) being mixed in specific ratios.

Abstract: A process and apparatus for the production of exposed printing plates consisting of a resin layer and a support, said resin layer being prepared from a fluid photopolymerizable material which is introduced into a mold having at least one transparent wall which is covered with an image-bearing transparency, and being exposed through said image-bearing transparency, which causes photopolymerization of the exposed areas of the resin layer and bonds these areas to the support which is provided with an adhesive layer.

Abstract: A process for the manufacture of thin layers based on polyurethane elastomers. A liquid reaction mixture essentially consisting of (A) polyesters, polyethers, polyester urethanes or polyether urethanes, all of which contain at least two hydroxyl groups in the molecule, and diisocyanates or (B) prepolymers obtained from the hydroxyl-containing compounds mentioned under (A) above with an excess of diisocyanates, said prepolymers containing at least two isocyanate groups in the molecule, and at least one of the compounds mentioned under (A) above which are capable of reacting with isocyanates, to which reaction mixture a minor quantity of substantially compatible monomers having at least two photocrosslinkable C--C multiple bonds and optionally a photopolymerization initiator have been added, is applied to a substrate to form a coating thereon, which coating is then gelled by irradiation and finally thermocured.

Abstract: The invention relates to relief plates for flexographic printing comprising a relatively soft elastomeric base (U) having a modulus of elasticity of from 10 to 200 kg/cm.sup.2 and a thickness of from 0.5 to 6 mm and, firmly bonded thereto, a thin, relatively hard, difficultly soluble intermediate layer Z having a modulus of elasticity of from 1 .times. 10.sup.3 to 2.1 .times. 10.sup.6 kg/cm.sup.2 and a thickness of from 5 to 500 .mu. and, firmly bonded to said intermediate layer Z, a relief layer P' consisting of a photocrosslinked elastomeric mixture having a modulus of elasticity of from 30 to 2000 kg/cm.sup.2 and a thickness of from 200 to 300 .mu., the modulus of elasticity of the photocrosslinked relief layer P' being the same as or higher than that of the base U and the neutral surface of the relief plate lying in or near the intermediate layer Z. The invention also relates to photosensitive laminates for the production of such plates.