Abstract: A letterpress printing method is disclosed wherein a printing plate, having plastic surface with a critical surface tension in the range of approximately 18-35 mN/m, is engraved or otherwise provided with raised ink-bearing impression sites and the printing plate is used for printing in a letterpress printing machine. As examples, the plastic surface of the printing plate may comprise a fluoropolymer, polytetrafluoroethylene or a copolymer of tetrafluoroethylene and hexafluoropropylene. The low surface tension is shown to enhance the printing quality in this environment.

Abstract: A process for manufacturing a planographic printing plate using a photosensitive planographic printing plate comprising a conductive support and provided thereon, a photoconductive layer containing an alkali soluble resin, a photoconductor and a photosolubilizable photosensitive compound comprises the steps of forming an electrophotographic latent image on the photoconductive layer, developing the latent image with liquid developer to form a toner image layer, uniformly exposing overall to actinic light the entire photoconductive layer, and removing the photoconductive layer where no toner image layer has been formed, the transmission density of the toner image layer to the actinic light being not less than 0.6, and the transmission density per unit thickness of the toner image layer to the actinic light being not less than 0.03 dm.sup.2 /g.

Abstract: Photocurable elements which are useful for preparing flexographic printing plates are provided which comprise a printing layer and a contiguous base layer, the printing layer comprising about 40 to 95 parts by weight of an elastomeric block copolymer, about 5 to 60 parts by weight of a second elastomeric polymer which is incompatible with the block copolymer, a photopolymerizable monomer, and a photoinitiator. The printing layer preferably also comprises an actinic radiation scattering and absorbing pigment.Also provided are relief printing plates prepared from the photocurable elements. The printing plates have a tack-free surface having excellent ink transfer properties, abrasion resistance, and solvent resistance. A high level of exposure latitude may also be provided in the photocurable elements of the invention.

Abstract: A photopolymer useful in preparing water-developable, solid printing plates is prepared by preparing a urethane prepolymer by reacting polyoxyalkylene diols or polyester diols, or a mixture thereof, with an excess of diisocyanate, followed by chain extending the resulting prepolymer mixture with an alkyldialkanolamine, then reacting the chain-extended product with a hydroxyalkyl(meth)acrylate. The resulting photopolymer is suitably formulated with additional photoactive (meth)acrylate monomers or oligomers and photoinitiator for casting or extrusion on a substrate to form a flexographic printing plate. Following UV exposure of the plate through a negative, unexposed areas can be removed by washing with a slightly acidic aqueous medium, to give a plate with a desirable relief image. The use of the aqueous washout solution as opposed to organic solvents minimizes pollution problems.

Abstract: A photosensitive resin composition suitable for producing a virgin flexographic printing plate, a process for the production thereof and a virgin flexographic printing plate. The photosensitive resin composition comprises (1) a photosensitive microgel obtained by emulsion-polymerizing (a) a compound having an .alpha., .beta.-ethylenically unsaturated double bond in the presence, as an emulsifier, of (b) a compound containing a tertiary ammonium salt to prepare (A) fine microgel particles and reacting the (A) fine microgel particles with (B) a compound having an epoxy group to react with the tertiary ammonium salt and at least one .alpha., .beta.-ethylenically unsaturated double bond per molecule, (2) a compound having an .alpha., .beta.-ethylenically unsaturated double bond, and (3) a rubber or thermoplastic elastomer.

Abstract: The invention relates to a process for producing flexographic printing reliefs by:(a) forming at least one photopolymerizable layer on a support, said layer being crosslinkable by photopolymerization;(b) imagewise exposing the layers to actinic radiation; and(c) removing the noncrosslinked portions of the layers with developer solvents;wherein the improvement comprises using developer solvents which have at least one component selected from the group consisting of: (a) diethylene glycol dialkyl ethers wherein the alkyl group has 1-5 carbon atoms; (b) acetic acid esters of alcohols selected from the group consisting of saturated alcohols having 6-10 carbon atoms and alkoxy substituted saturated alcohols having 6-10 carbon atoms; (c) carboxylic acid esters of acids having 6-10 carbon atoms and alcohols having 1-6 carbon atoms; and (d) esters of alkoxy substituted carboxylic acids wherein the acid has from 2-4 carbon atoms, the alkoxy substituent has from 1-4 carbon atoms, and alcohols having 1-4 carbon atoms.

Abstract: A photopolymer useful in preparing water-developable, solid printing plates is prepared by preparing a urethane prepolymer by reacting polyoxyalkylene diols or polyester diols, or a mixture thereof, with an excess of diisocyanate, followed by chain extending the resulting prepolymer mixture with an alkyldialkanolamine, then reacting the chain-extended product with a hydroxyalkyl(meth)acrylate. The resulting photopolymer is suitably formulated with additional photoactive (meth)acrylate monomers or oligomers and photoinitiator for casting or extrusion on a substrate to form a flexographic printing plate. Following UV exposure of the plate through a negative, unexposed areas can be removed by washing with a slightly acidic aqueous medium, to give a plate with a desirable relief image. The use of the aqueous washout solution as opposed to organic solvents minimizes pollution problems.

Abstract: The present invention relates to a letterpress for transferring on which a dot-like fine form plate surface is formed closely resembling a photoimage, and to a method of transferring by use of the letterpress for transferring. The letterpress is formed by exposing a photosensitive resin through a photofilm to a parallel light to harden the film of the photosensitive resin corresponding to the lightscreening area of the photofilm. The area of the photo resin other than the hardened film is then removed by rinsing with water to form the letterpress which has a convex corresponding to the light-penetrating area of the photofilm. The convex is then directly coated with various dyes and press printed on and transferred to a transfer material, or the convex is coated with a photosensitive resin and press printed on a transfer material.

Abstract: A flexographic printing plate comprising in the following order: a flexible substrate, a photohardenable composition, and a colloidal vanadium oxide antistatic layer. The antistatic layer provides protection from static induced defects until and after the flexographic plate is processed.

Abstract: Flexographic photosensitive printing plates are made with formulations comprising block polymers having an architecture of BA, CBA or CBCA, where A is poly(vinylpyridine), B is poly(butadiene) or poly(isoprene) and C is styrene. The polymers may be quaternized or neutralized with an organic acid. When made with quaternized polymers, the plates after imaging with UV may be developed in aqueous solutions. The block polymers offer further advantages as to ease of synthesis, safety and improved resolution.

Abstract: A radiation-sensitive mixture suitable for producing relief patterns comprises(a) a water-insoluble but alkali-soluble polymeric binder,(b) an organic compound whose solubility in an alkaline developer is increased by the action of acid and which contains at least one acid-cleavable group and additionally a group which forms a strong acid on irradiation, and additionally(c) an organic compound which reacts with water or stronger nucleophiles at up to 120.degree. C.

Abstract: A photoresin printing plate having a Shore A hardness at 20.degree. C. of 25 to 60, an impact resilience at 20.degree. C. of 35% or more as measured by a falling ball method and a surface tack at 20.degree. C. of 40 g/cm or less has been found not only to be capable of providing prints having an image of high precision but also to be capable of releasing the paper dust or the like, which has adhered to the printing plate, in a short period of time during the printing operation, so that it did not become necessary to interrupt the printing operation in order to clean the printing plate, which leads to an efficient production of the prints.

Abstract: A method and associated apparatus for forming an image replication medium on a surface of a printing plate or cylinder in which the surface is initially coated with a layer of photopolymer liquid. Thereafter, selected areas of the layer of liquid coated on the surface are hardened by exposure to a beam produced by a computer controlled laser to provide a surface cylinder having an image replication medium with a desired pattern.

Abstract: A photosensitive resin printing plate which can provide printed matter with good ink coverage and little dot gain, and a plate making apparatus used therefor.

Abstract: A photocured resin relief plate comprising a relief layer comprising base layer A and top layer B formed by photocuring and arranged in this order, in which the thickness of the relief layer at a highlight portion constituting a pattern having a dot percent of 7% or less is smaller than the thickness of the relief layer at a portion other than the highlight portion. The photocured resin relief plate can be obtained by imagewise light exposure of a multilayer photosensitive resin layer comprising a lower layer of a liquid photosensitive resin layer having minimum insolubilization light exposure value Q.sub.A and an upper layer of a liquid photosensitive resin layer having minimum insolubilization light exposure value Q.sub.B, wherein Q.sub.B is not smaller than 23 millijoules/cm.sup.2 and not smaller than 5 times Q.sub.A.

Abstract: A photosensitive printing element having an IR ablatable layer and at least one barrier layer as set forth within and a process for making a flexographic printing plate from such an element are disclosed.

Abstract: A seamless, trilaminate, photopolymer cylindrical printing plate useful in a variety of printing processes, including the flexographic, letter press, dry-offset, intaglio, and gravure processes, capable of millions of printing runs with minimal degradation. The seamless, photopolymer, cylindrical printing plate has a seamless trilaminate cylindrical sleeve with a constant cross-sectional diameter and a longitudinal axis, a clear matte sealant layer completely covering the seamless trilaminate cylindrical sleeve, a bonder layer completely covering the clear matte sealant layer, and a photopolymer layer completely covering the bonder layer. A pigmented primer layer may completely cover the matte sealant layer and be completely covered by the bonder layer. A hardening layer and an anti-oxidant layer may completely cover the photopolymer layer. A method of manufacturing the seamless, trilaminate, photopolymer cylindrical printing plate is also provided.

Abstract: A method for laser engraving photopolymer printing plates is provided. Prior to the laser engraving step (30), the photopolymer material is totally cured, followed by removal of a release layer disposed on the material. The laser engraving step (30) which follows removal of the release layer produces a plurality of tacky particulates (120) which adhere to the surface layer of the photopolymer material (100) adjacent the ablated regions (110). The particulates (120) are removed in a solvent washing step (40) to provide clean sharp edges (115) adjacent the ablated regions (110). Subsequent to removal of the photopolymer residue (120) the engraved printing plate is finished, by either chemical or light finishing methods.

Abstract: A photoresin relief printing plate comprising a support and a photoresin relief portion disposed thereon, said relief portion having a thickness of not greater than 8 mm and comprising an upper photoresin layer and a lower photoresin layer, wherein said upper photoresin layer has a thickness of at least 2 .mu.m and a Young's modulus of not greater than 650 kg/cm.sup.2 and said lower photoresin layer has a thickness which is greater than the Young's modulus of said upper photoresin layer and a thickness which is greater than the Young's modulus of said upper photoresin layer. The photoresin relief printing plate exhibits not only excellent inking and ink transferability even in solid images, but also excellently less broadening of printed images and excellent image reproducibility, even if the printing operation is performed using an ordinary relief printing machine having poor machine accuracy.

Abstract: In a novel, improved process for the production of photopolymeric flexographic relief printing plates from photosensitive recording elements which containA) a dimensionally stable substrate andB) at least one photopolymerizable recording layer havingb.sub.1) at least one elastomeric polymer as a binder,b.sub.2) at least one photopolymerizable monomer which is compatible with the binder (b.sub.1) andb.sub.3) at least one photopolymerization initiator,by(1) imagewise exposure of the photopolymerizable recording layer (B) to actinic light and(2) washout (development) of the unexposed and therefore nonphotopolymerized parts of the imagewise exposed recording layer (B) with an organic developer with formation of a relief layer,the organic developers used are 3-methoxy-n-butyl acetate and/or n-butyl glycolate.

Abstract: A light-curable elastomeric mixture is described, containinga) an elastomeric binder or binder mixture,b) a low molecular-weight compound which is polymerizable by a free-radical mechanism, is compatible with said binder or binder mixture, has at least one ethylenically unsaturated end group and has a boiling point above 100.degree. C. at normal pressure, andc) a compound or combination of compounds which is capable of initiating the polymerization of compound (b) under the action of actinic light,wherein said elastomeric binder is a block copolymer, soluble or dispersible in water or in an aqueous solution, having a structure selected from the group consisting of A--B, B--A--B, C--A--B, C--A--C--B, B--C--A--C--B, A.sub.n XB.sub.n, (A--B).sub.x X, C.sub.n X(A--B).sub.n, (C--A).sub.n XB.sub.n, (C--A--B).sub.n X, C.sub.n X(A--C--B).sub.n, (C--A).sub.n X(C--B).sub.n, (C--A--C).sub.n XB.sub.n, (C--A--C--B).sub.n X, B.sub.n XA.sub.n XB.sub.n, X(B--A--B).sub.n X, (B--C).sub.n XA.sub.n X(C--B).sub.n, B.sub.

Abstract: Disclosed is a photosensitive elastomer composition comprising (1) a thermoplastic block copolymer comprising at least one monovinyl substituted aromatic hydrocarbon polymer block and at least one conjugated diene polymer block, wherein a monovinyl substituted aromatic hydrocarbon content (A) is 10 to 35% by weight, and the vinyl content (V) of a conjugated diene is 20 to 50%, and the (A) and the (V) satisfy the formula: 40.ltoreq.(A)+(V).ltoreq.70; (2) an ethylenically unsaturated compound component; and (3) a photopolymerization initiator.

Abstract: A method for producing a photocured image structure, comprising providing a selectively photocured elastomer composition layer having a photocured image portion and an uncured portion, and contacting the selectively photocured elastomer composition layer with a developer comprising a specific ester and optionally a specific alcohol in a specific volume ratio, to wash-out the uncured portion and develop the photocured image portion, thereby obtaining the photocured image structure. By this method, not only is the swelling of the image structure minimized but also the danger of relief breakage and orange peel formation is eliminated, so that an excellent photocured image structure can be produced by a simple operation.

Abstract: In a novel process for the production of a flexographic relief printing plate from a photosensitive recording element which containsA) a dimensionally stable substrate andB) at least one photopolymerizable recording layer havingb.sub.1) at least one elastomeric polymer as a binder,b.sub.2) at least one photopolymerizable monomer which is compatible with the binder (b.sub.1) andb.sub.3) at least one photopolymerizable initiator, by(1) imagewise exposure of the photopolymerizable recording layer (B) to actinic light and(2) washout (development) of the unexposed and therefore nonphotopolymerized parts of the imagewise exposed recording layer (B) with an organic developer with formation of a relief layer,wherein the organic developer contains from 1 pphm (1 part per 100,000,000) to 3% by weight, based on its total amount, of at least one antistatic agent.

Abstract: A positive radiation-sensitive mixture is disclosed which contains a compound which forms an acid under the action of high-energy radiation, and an acid-cleavable compound, wherein the compound which forms an acid contains aliphatically bound halogen (chlorine or bromine) and has a pK.sub.a value of less than about 12 or is a derivative of a compound having such a pK.sub.a value which can be converted into the free compound by acid catalysis. A positive recording material and a process for recording high-energy radiation using the material are also disclosed. The mixture, and in particular the recording material produced therefrom, has relatively high sensitivity and improved resolution and, in addition, does not exhibit image fogging after development.

Abstract: Negative-acting flexographic printing plates display enhanced performance when backside irradiated with ionizing radiation instead of longer wavelength ultraviolet radiation. A better defined floor and more readily controlled floor is produced on the final printing plate.

Abstract: An improved method for selectively curing a liquid photosensitive resin by masking exposure is provided, wherein rough, uneven or irregular contact is provided directly or indirectly between the masking film and the substrate. Due to this feature, no interfacial cohesion occurs between the lower surface of the masking film facing the substrate and the upper surface of the substrate facing the masking film. Thus, there are no air pockets formed between the two surfaces. Therefore, there is no danger that the substrate will be caused to protrude into the resin layer so that the ultimate printing plate would have an undesirable local decrease in thickness. As a result, by the method of the present invention, a printing plate having a high degree of uniformity in thickness, can be obtained with reproducibility.

Abstract: A photopolymerizable printing element comprising a photopolymerizable layer and an elastomeric layer applied thereon wherein said elastomeric layer further comprises at least one thermoplastic, elastomeric block copolymer and at least one polymer with a structural unit containing a maleic acid half ester group. The element produces flexographic printing plates having improved printing performance with aqueous and alcoholic printing inks.

Abstract: A radiation-sensitive mixture is disclosed which contains as essential constituentsa) at least one thermoplastic, elastomeric block copolymer of the formulae(A-B).sub.m -A, (B-A).sub.m+a -B, (A-B).sub.m+1 or (A-B).sub.o Y,in whichA is a thermoplastic, nonelastomeric polymer block having a glass transition temperature of 25.degree. C. or above andB is an elastomeric polymer block having a glass transition temperature of 10.degree. C. or below,Y is Sn or Si,m is an integer from 1 to 10, ando is 2 if y is Sn, or 4 if y is Si,b) at least one ethylenically polyunsaturated compound, andc) a photopolymerization initiator,wherein at least one of the ethylenically polyunsaturated compounds corresponds to the formula I ##STR1## where R is a straight-chain or branched alkyl radical,X is a straight-chain alkylene or cycloalkylene, it being possible for individual methylene groups to be substituted by --O--, --S--, carbonyl or carbonyloxy groups, and n is 1 to 5.

Abstract: A photopolymerizable printing element comprising a photopolymerizable layer and an elastomeric layer coated thereon wherein said elastomeric layer contains at least one thermoplastic, elastomeric block copolymer and at least one reaction product of an epoxide resin with a rosin derivative. The element produces flexographic printing plates having improved printing results with aqueous and alcoholic printing inks.

Abstract: Disclosed is a photosensitive resin composition which has improved water developability and storage stability. The composition comprises(I) crosslinked resin particles prepared by a post-emulsion method from(a) a base resin having a glass transition temperature (Tg) of 0.degree. C. or less and a polymerizable double bond,(b) a monomer which, when polymerized, provides a resin in which Tg is 20.degree. C. higher than that of the base resin, or a resin in which Tg is 20.degree. C. higher than that of the base resin,(c) a polyvinyl compound, and(d) a polymerization initiator(II) a photopolymerizable unsaturated monomer, and(III) a photopolymerization initiator.

Abstract: A method and composition for developing a relief image formed by exposing a portion of a photopolymerizable layer to actinic radiation and removing the portion of the photopolymerizable layer not exposed to actinic radiation by washing the unexposed portion with a developer composition comprising a monoterpene, N-methylpyrrolidone and, optionally, an aromatic alcohol. A nonionic surfactant can also be included in the developer composition.

Abstract: The present invention relates to a letterpress for transferring on which a dot-like fine form plate surface is formed closely resembling a photoimage, and to a method of transferring by use of the letterpress for transferring. The letterpress is formed by exposing a photosensitive resin through a photofilm to a parallel light to harden the film of the photosensitive resin corresponding to the lightscreening area of the photofilm. The area of the photo resin other than the hardened film is then removed by rinsing with water to form the letterpress which has a convex corresponding to the light-penetrating area of the photofilm. The convex is then directly coated with various dyes and press printed on and transferred to a transfer material, or the convex is coated with a photosensitive resin and press printed on a transfer material.

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: Negative-acting photohardenable compositions are useful in flexographic printing plate manufacture without the use of solvent development. Unhardened composition is softened and absorbed by an absorbent sheet. Absorbed composition can be removed from the sheet and recycled.

Abstract: A water-developable photosensitive resin plate suitable for the manufacture of a relief printing plate having high resistance to water-based inks, high resilience and excellent form stability, which comprises:(A) a copolymer comprising units of (i) an aliphatic conjugated diene monomer (ii) and .alpha., .beta.-ethylenically unsaturated carboxylic acid and (iii) a polyfunctional vinyl monomer, optionally with (iv) a monofunctional vinyl monomer, the content of the aliphatic conjugated diene monomer (i), the .alpha., .beta.-ethylenically unsaturated carboxylic acid (ii), the polyfunctional vinyl monomer (iii) and the monofunctional vinyl monomer (iv) being respectively from about 5 to 95 mol %, from about 1 to 30 mol %, from about 0.1 to 10 mol % and 0 to 70 mol % based on the combination of those monomeric components;(B) a basic nitrogen atom-containing compound;(C) an ethylenically unsaturated monomer; and(D) a photopolymerization initiator.

Abstract: A method is provided for producing relief images having improved image fidelity and resolution. The method comprises positioning an image bearing negative transparency closely adjacent and substantially parallel to a layer of a photocurable material; positioning on the other side of the negative from the photocurable material and in substantially parallel relationship thereto at least one louver having a plurality of open cells, each cell extending through the louver along an axis perpendicular to the negative and having reflective side surfaces contoured to reflect and redirect rays of radiant energy incident thereon to a direction more normal to the negative surface; and passing radiant energy which is capable of curing the photocurable material through the louver and the negative and onto and through the photocurable material for a time sufficient to form a latent relief image in the photocurable material.

Abstract: A photosensitive elastomeric composition and process of using the composition to prepare flexographic printing plates having substantially improved solvent resistance are described.

Abstract: A continuous process for the manufacture of photopolymer plates having a precise and constant thickness in which the components of the photopolymer layer are melted in a screw extruder, the melt is conveyed to the sheet die by means of a gear pump and then into a roll gap of a calender, wherein the melt leaving the sheet die does not form a rotating bead in the calender gap downstream therefrom. The photopolymer plates prepared in this manner have high homogeneity of the components of the photopolymerizable mixture, have a highly precise and constant thickness, are transparent, do not tend to form specks and guarantee a long shelf life.

Abstract: In a novel process for the production of a flexographic relief printing plate from a photosensitive recording element which containsA) a dimensionally stable substrate andB) at least one photopolymerizable recording layer havingb.sub.1) at least one elastomeric polymer as a binder,b.sub.2) at least one photopolymerizable monomer which is compatible with the binder (b.sub.1) andb.sub.3) at least one photopolymerization initiator,by(1) imagewise exposure of the photopolymerizable recording layer (B) to actinic light and(2) washout (development) of the unexposed and therefore nonphotopolymerized parts of the imagewise exposed recording layer (B) with an organic developer with formation of a relief layer,the organic developer used contains, based on its total amount, from 10% to 95% by volume of at least one mineral oil fraction from which aromatics have been removed and which has a boiling range of 150.degree. to 260.degree. C. and a flashpoint above 45.degree. C.

Abstract: The present invention relates to a presensitized plate for use in making a lithographic plate requiring no dampening water and comprising, on a support, a light-sensitive resin layer and a silicone rubber layer, in this order, wherein the silicone rubber layer is crosslinked by addition reaction of an .fwdarw.SiH group with a --CH.dbd.CH-- group and wherein the light-sensitive resin layer comprises: (1) a monomer or oligomer having at least one photopolymerizable or photo-crosslinkable and olefinically unsaturated double bond, (2) an organic solvent-soluble polyurethane resin having a glass transition temperature of 20.degree. C. or below and being capable of forming a film, and (3) a photopolymerization initiator. According to the present invention, the PS plate has excellent image-forming properties and printing properties.

Abstract: A relief printing plate whose photopolymerized relief layer has a non-tacky surface is produced by (1) imagewise exposure of a photopolymerizable relief-forming recording layer which contains one or more polymeric binders containing acid groups, (2) washing out (development) of the unexposed and therefore non-photopolymerized parts of the imagewise exposed relief-forming recording layer with a developer and (3) aftertreatment of the resulting photopolymerized relief layer with a basic aftertreatment solution.

Abstract: The invention describes a developing solvent for layers which are crosslinkable by photopolymerization and contain a binder based on an elastomeric polymer, a photopolymerizable monomer compatible therewith and a photoinitiator. The developing solvent comprises a phenol ether of the general formula I ##STR1## wherein R.sup.1 denotes (C.sub.1 -C.sub.6)n-alkyl or iso-alkyl, cycloalkyl or (C.sub.6 -C.sub.12)-aryl andR.sup.2 denotes hydrogen, (C.sub.1 -C.sub.6)n-alkyl or iso-alkyl or --OR.sup.1, and a relatively high-boiling alcohol.Compared with solvents of the prior art, the developing solvent of the present invention is non-toxic, can quickly be removed from the layer and has a high capacity for layer components.

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: Disclosed is a water-developable photosensitive resin composition capable of hot melt molding, which comprises:(i) a water soluble or water dispersible polyvinyl alcohol prepared by saponifying a copolymer of a vinyl ester and another copolymerizable monomer, which has a saponification degree of the vinyl ester unit of 50 to 70 mol % and a hot melt flow starting temperature of 60.degree. to 130.degree. C.,(ii) a polymerizable monomer, and(iii) a photopolymerization initiator.

Abstract: A process for substantially improving dimensional stability in photopolymeric flexographic relief printing plates wherein the surface of the printing plate is post-exposed to a high intensity radiation source having broad wavelength emission in the 200 to 700 nm range.

Abstract: A photosensitive element adapted for the preparation of colored images is disclosed. The photosensitive element comprises: a photosolubilizable layer consisting essentially of an acid-labile polymer and a photosolubilizing agent; an elastomeric layer; and a support. It can be processed by aqueous solvents, preferably ordinary tap water.

Abstract: A presensitized plate for use in making a lithographic printing plate requiring no dampening water comprises a substrate provided thereon with in order: (1) a photopolymerizable light-sensitive layer which comprises a monomer or an oligomer having at least one photopolymerizable olefinically unsaturated double bond, an organic solvent-soluble polyurethane resin or polyamide resin which is solid at room temperature and has film-forming ability and a photopolymerization initiator; (2) a crosslinked silicone rubber layer; and (3) a transparent cover coat layer, wherein the photopolymerization initiator comprises dialkylaminoarylcarbonyl compounds and at least one member selected from the group consisting of xanthones, thioxanthones, acrydones, benzophenones which do not carry a dialkylamino group, benzanthrones and anthraquinones and the transparent cover coat layer is formed from a biaxially oriented polypropylene film having a thickness ranging from 6 to 22 .mu.

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 dry PS plate comprises a substrate provided thereon with in order a primer layer, a light-sensitive layer and a silicone rubber layer wherein the primer layer comprises at least one compound selected from the group consisting of those having urethane or/and urea bonds and is adhered to the substrate with a functional group containing silane coupling agent represented by the following general formula: ##STR1## wherein n is an integer ranging from 1 to 3; X represents an alkyl group, a vinyl group or an organic group having a functional group showing affinity to or capable of being bonded to the compound included in the primer layer; R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; and Y represents an organic group which generates a hydroxyl group through hydrolysis or a hydroxyl group.