Abstract: A novel photosensitive recording element having a dimensionally stable substrate (A), a photopolymerizable relief-forming recording layer (B), which may consist of two or more individual layers (B), and an optically transparent top layer (C) firmly adhering to the surface of (B) is used for the production of a flexographic relief printing plate. Imagewise exposure of the photopolymerizable relief-forming recording layer (B) of the novel photosensitive recording element to actinic light results in a difference between the solubilities of its exposed and unexposed parts, so that its unexposed parts can be washed out (developed) with a solvent. On the other hand, the optically transparent top layer (C) of the novel photosensitive recording element is insoluble or nonswellable in the relevant solvent. The imagewise exposed novel photosensitive recording element can nevertheless be developed in one operation with the aid of an emulsion of the water-in-oil or oil-in-water type.

Abstract: A new liquid cleaner composition is provided for the mild and gentle removal of polymeric materials from sufaces without leaving any residues. The said new cleaner composition is an emulsion of the water-in-oil type comprising an aqueous phase finely dispersed in a continuous phase selected from the group consisting of nonflammable, fire-retardant, high-boiling, and fire-retardant and high-boiling organic phases, the volume ratio of the finely dispersed aqueous phase to the continuous organic phase being in the range of from 90:10 to 10:90. The new liquid cleaner composition can contain alcohols, surface-active agents and further useful additives. The new liquid cleaner composition is most preferably used in the process for preparing photopolymerized flexographic relief printing plates as the developer for washing out the non-irradiated and thus non-photopolymerized areas of the imagewise irradiated relief-forming recording layers of the said flexographic relief printing plates.

Abstract: A novel optically transparent polymer alloy comprisesA) at least one elastomer which contains ethylene and propylene as copolymerized units andB) at least one elastomer which contains ethylene and (meth)acrylic acid as copolymerized units,and is used as a molding material or for the production of molding materials, moldings, films, coatings, adhesives and photosensitive recording elements.

Abstract: A flexographic printing plate which is resistant to ozone cracking and where the flexible recording layer has an anisotropy factor AF of <1.5 is produced from a photosensitive mixture consisting of A) one or more elastomeric binders,B) a mixture ofB1) from 5 to 20% by weight of one or more photopolymerizable organic compounds which are compatible with (A) and contain two or more olefinic double bonds andB2) from 1 to 15% by weight of one or more monoolefinically unsaturated organic compounds which are compatible with (A) and whose homopolymer has a glass transition temperature which is below room temperature,C) from 0.1 to 10% by weight of one or more photoinitiators andD) from 0 to 27% by weight of conventional assistants and additives,the anisotropy factor AF of the flexible recording layer being defined as the ratio of the moduli of elasticity at 100% elongation of strips measuring 2.times.

Abstract: The present invention relates to an improved process for preparing a photopolymerized flexographic relief printing plate or a photoresist from a photosensitive element comprising a photopolymerizable layer consisting essentially of(A) at least one polymer as the binder,(B) at least one photopolymerizable monomer compatible with said binder (A) and(C) one photoinitiator, by(i) imagewise exposing said photopolymerizable layer of said element to actinic light and(ii) washing out the unexposed, non-photopolymerized parts of said layer with a developer, thereby obtaining a photopolymerized flexographic relief printing plate or a photoresist.The improvement of said process comprises: washing out the non-photopolymerized parts of the irradiated photopolymerizable layer with the developer which consists essentially of at least one hydrogenated petroleum fraction having a flashpoint above 45.degree. C. and a boiling range of from 160.degree. to 220.degree. C.

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: In a process for preparing a photopolymer printing plate, relief plate or photoresist from a photosensitive recording element containingA) a photopolymerizable relief-forming layer which can be developed with liquid developer after imagewise exposure to actinic light,B) a top layer which consists of polymers forming films of high tensile strength, adheres firmly to the photopolymerizable relief-forming layer (A) and is soluble or swellable in the liquid developers andC) a cover sheet which can readily be peeled off from the top layer (B),comprising peeling off the cover sheet (C) from the top layer (B), imagewise exposing to actinic light and developing the relief-forming layer (A), the formation of an electrostatic charge on top of the photosensitive recording element being prevented by incorporating into the element a top layer (B) containing specific tertiary amines and/or amides and/or specific quaternary ammonium salts.

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: In a photosensitive recording material comprising(A) a photopolymerizable relief-forming layer which can be developed with liquid developer after imagewise exposure to actinic light,(B) a top layer which consists of polymers forming films of high tensile strength, adheres firmly to the photopolymerizable relief-forming layer (A) and is soluble or swellable in the liquid developers and(C) a cover sheet which can readily be peeled off from the top layer (B),the top layer (B) contains specific tertiary amines and/or amides and/or specific quaternary ammonium salts of the type defined in more detail in the claims.Photopolymerized printing plates, relief plates or photoresists are produced by a process in which this recording material is used.

Abstract: A flexographic printing plate which is resistant to ozone cracking and where the flexible recording layer has an anisotropy factor AF of <1.5 is produced from a photosensitive mixture consisting of(A) one or more elastomeric binders,(B) a mixture of(B1) from 5 to 20% by weight of one or more photopolymerizable organic compounds which are compatible with (A) and contain two or more olefinic double bonds and(B2) from 1 to 15% by weight of one or more monoolefinically unsaturated organic compounds which are compatible with (A) and whose homopolymer has a glass transition temperature which is below room temperature,(C) from 0.1 to 10% by weight of one or more photoinitiators and(D) from 0 to 27% by weight of conventional assistants and additives,the anisotropy factor AF of the flexible recording layer being defined as the ratio of the moduli of elasticity at 100% elongation of strips measuring 2.times.

Abstract: Relief plates crosslinked by photopolymerization are produced by exposing layers which are crosslinkable by photopolymerization imagewise to actinic light and washing out the noncrosslinked parts of the layers with a developer, by a process in which the developer used contains, as an essential component, a branched or straight-chain, monoolefinically, diolefinically or triolefinically unsaturated acryclic or saturated or monoolefinically, diolefinically or triolefinically unsaturated cyclic aliphatic hydrocarbon, alcohol or ketone of 8 to 15 carbon atoms.