CA2047302A1 - Photopolymerizable printing plate for flexographic printing - Google Patents
Photopolymerizable printing plate for flexographic printingInfo
- Publication number
- CA2047302A1 CA2047302A1 CA002047302A CA2047302A CA2047302A1 CA 2047302 A1 CA2047302 A1 CA 2047302A1 CA 002047302 A CA002047302 A CA 002047302A CA 2047302 A CA2047302 A CA 2047302A CA 2047302 A1 CA2047302 A1 CA 2047302A1
- Authority
- CA
- Canada
- Prior art keywords
- photopolymerizable
- elastomeric
- equal
- layer
- polystyrene
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/027—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds
- G03F7/032—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds with binders
- G03F7/033—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds with binders the binders being polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. vinyl polymers
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- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Spectroscopy & Molecular Physics (AREA)
- General Physics & Mathematics (AREA)
- Photosensitive Polymer And Photoresist Processing (AREA)
- Manufacture Or Reproduction Of Printing Formes (AREA)
Abstract
TITLE
PHOTOPOLYMERIZABLE PRINTING
PLATE FOR FLEXOGRAPHIC PRINTING
ABSTRACT
A photopolymerizable printing element comprising a photopolymerizable layer and an elastomeric layer, wherein the elastomeric layer contains, as a binder, one or more thermoplastic, elastomeric block copolymers made up of at least one polystyrene block and at least one polybutadiene, polyethylene, and/or polypropylene block.
The polystyrene content of the binder or binder mixture is 10 to 35 percent by weight, the solution viscosity of the block copolymers for a 5.23% solution in toluene is greater than or equal to 5 mm2/s and the melt index, measured according to ASTM D 1238 P is less than or equal to 10 g/10 min.
PHOTOPOLYMERIZABLE PRINTING
PLATE FOR FLEXOGRAPHIC PRINTING
ABSTRACT
A photopolymerizable printing element comprising a photopolymerizable layer and an elastomeric layer, wherein the elastomeric layer contains, as a binder, one or more thermoplastic, elastomeric block copolymers made up of at least one polystyrene block and at least one polybutadiene, polyethylene, and/or polypropylene block.
The polystyrene content of the binder or binder mixture is 10 to 35 percent by weight, the solution viscosity of the block copolymers for a 5.23% solution in toluene is greater than or equal to 5 mm2/s and the melt index, measured according to ASTM D 1238 P is less than or equal to 10 g/10 min.
Description
s~z~ ;i3~
PHOTOPOLYMERIZABLE PRINTING
PLATE FOR FLEXOGRAPHIC PRINTING
FIELD QF TH~ INVENTION
This invention relates ~o flexographic printing plates and more particularly to photopolymerizable printing elements comprising a photopolymerizable layer and an elastomeric layer ~oated thereon, wherein the elastomeric layer contains, as a binder, at least one or more thermoplastic, elastomeric block copolymers, made up of at least one polystyrene block and, at least one polybutadiene, polyethylene, and/or polypropylene block.
BACKGROUND OF THE INVENTION
Photopolymerizable recording materials are known for use in the manufacture of printing plates for flexographic printing, in which the printing plate is produced by exposing imagewise a light-sensitive layer and removing the unexposed areas of the layer. Examples of such recording materials are disclosed in DE-C 3 22 15 090 ~U.S. Patent Nos. 4,323,636, 4,323,637, 4,369,246 and 4,423,135), U.S. Patent No. 4,266,005, U.S. Patent No. 4,320,lR8, U.S. Patent No. 4,126,4~6, and U.S. Patent No. 4,430,417. Such photopolymerizable ~5 printing plates usually comprise a support, optionally an adhesive or other support coating, a photopolymerizable layer containing at least one polymeric binder, at least one ethylenically unsaturated monomer addition-polymerizable by actinic radiation, a photoinitiator or photoinitiator system, and a cover layer. Typically, a flexible, tear-resistant polymeric film is interposed between the photopolymerizable layer and the cover layer. The polymeric film serves as a protective layer in that it enables adhesion-free placement of the negative transparency for exposure of 6~ ~ ~ ' 1 Si, J ,Y
the printing plate. It also allows for good, bubble-free contact between the transparency and the printing plate. Examples of such protective layers are disclosed in U.S. Patent No. 9,423,135 and DE-C 23 37 6~5 tU.S.
Patent No. 3,895,949).
Photopolymerizable printing plates can be prepared from any one of several methods. However, a preferred method utili~es a calendering process whereby a previously extruded, photopolymerizable composition is fed into the nip of a calender and is calendered between a support and a cover element, thus forming between them a photopolymerizable layer.
Another method for preparing photopolymerizable printing plates is disclosed in EP-~1 00 84 851 ~U.S.
Patent Nos. 4,427,759 and 4,460,675) which teach a process for preparing a multilayer, photopolymerizable printing element comprising a flexible, tear-resistant polymer layer and a photopolymerizable layer, wherein between said layers is an elastomeric layer having an elastomeric binder, optionally a second binder, optionally a dye, optionally one or more monomers, and optionally a photoinitiator.
Positioning the image transparency on the elastomeric layer is possible provided the cover layer, which is removed before exposure, contains a special silicone layer which partially remains on the elastomeric layer. However, this process is bothersome and is feasible only for special cover layers and elastomeric intermediate layers. Moreover, the use of such silicone layers presents disadvantages in washoff development, because the silicones are insoluble in the developer solution and cause adhesion among the washoff brushes.
Another disadvantage of the photopolymerizable printing plates described above is that the flexi~le polymer layer required for adhesion-free, bubble-free placement of the negative complicates development of the exposed plates. The different solution behavior of the flexible polymer layer compared to the components of the photopolymerizable layer requires an additional development step, such as prior removal of the polymer layer, treatment with a special solvent, or additives in the actual developer solution. Many of these protective layers also swell in the developer solvent and can be removed only by intensive mechanical treatment.
In addition, each printing plate requires a polymeric protective layer coordinated specifically with its photopolymerizable layer. Thus, the composition of the polymer layer must be adapted to each photopolymerizable printing plate. This generates significant development and storage costs for the various types of layers. For this reason, and because of the additional process steps required in making and coating the polymer layer onto the photopolymerizable layer, production costs for printing plates are increased and the entire production process becomes more time-consuming. Furthermore, the basic incompatibility of the usual protective layers of polyamide films and the elastomeric block copolymers frequently employed as 2S binders in flexographic plates leads to permanent problems of delamination between the protective layer and the photopolymerizable layer.
Accordingly, the object of the present invention is to eliminate the above-cited d~fficultieq and disadvan~ages and make available a photopolymerizable printing plate whose surface is not tacky, so that direct placement of an image transparency on the printing plate is possible without damaging or spotting the transparency. At the same time, good bubble-free contact must be assured between the image transparency r~ ;~ 3 ~
and printing plate. The printing plate should also be easier and less expensive to produce and process.
Furthermore, conventional washoff development with current solvents should be possible without additives.
The ozone stability of the printing plates should also be increased. Concurrently, oth~er properties of the photopolymerizable printing plates should not be affected adversely. For example, a decrease in photosensitivity should be avoided and the flexographic printing plates should not swell as a result of the printing inks, because such swelling causes undesirable dot growth and thus, flawed printing.
~ urprisingly, the aforementioned objectives are achieved by using a photopolymerizable printing element comprising ~a) a support, (b) a photopolymerizable layer containing at least one elastomeric binder, at least one ethylenically unsaturated monomer addition-polymerizable by actinic radiation, a photoinitiator or photoinitiator system, ~c) an elastomeric layer containing at least one thermoplastic, elastomeric block copolymer, and (d) a cover sheet.
SUMMARY OE THE INVEN~IQ~
The invention relates to a photopolymerizable printing element comprising:
(a) a support;
(b) a photopolymerizable layer having at least one elastomeric binder, at least one ethylenically unsaturated monomer addition-polymerizable by actinic radiation, and a photoinitiator or photoinitiator system;
(c) an elastomeric layer having at least one thermoplastic, elastomeric block copolymer; and (~) a cover sheet, wherein the elastomeric layer (c) further comprises as a binder, one or more thermoplastic, elastomeric block -copolymers, made up o~ at least one polystyrene block and at least one polybutadiene, polyethylene, and/or polypropylene block, the binder or binder mixture having a polystyrene content of 10 to 35 percent by weight, a solution viscosity for a 5.23~ solution in toluene greater than or equal to 5 mm2/s, and a melt index less than or equal to 10 g/10 min.
Another aspect of the invention relates to a process for preparing a photopolymerizable printing element.
A further aspect of the invention relates to a process for preparing a coating solution for the elastomeric layer (c) of the photopolymerizable printing element.
The invention also relates to a process for preparing flexographic printing plates.
DETAI~ED ~SÇRIPTION OF THE INVENTION
The photopolymerizable printing element of the invention utilizes an elastomeric layer (c1 containing a binder of one or more thermoplastic, elastomeric block copolymers made up of at least one polystyrene block and at least one polybutadiene, polyethylene, and/or polypropylene block, wherein the polystyrene content of the binder or binder mixture is 10 to 35 percent by weight, the solution viscosity of the block copolymer for a 5.23% solution in toluene is greater than or equal to 5 mm2/s, and the melt index measured according to ASTM D 1238 P is less than or equal to 10 g/10 min.
The elastomeric layer adheres well to the photopolymerizable layer so that delamination problems do not ar~se. Printing plates for flexographic printing prepared from the invention show good printing properties compared to plates prepared from conventional printing elements. The surface of the printing plate is resistant to flexographic printing inks, even in large r~
printing runs. Surface swelling is not observed and print quality is uniformly good.
A particular advantage is that the printing plates of the invention show good flexibility. In addition, the surface is not brittle, and the printing plates do not crease under high bearing pressure.
The use of only one developer solvent enables simpler and more reliable quality control in washoff development of the exposed printing plates.
Furthermore, the washoff rate is increased compared to conventional printing plates that have a polyamide layer.
The thermoplastic, elastomeric block copolymers in the elastomeric layer (c) of the claimed invention are made up of at least one polystyrene block and at least one polybutadiene, polyethylene, and/or polypropylene block. Polystyrene/polybutadiene or polystyrene/polybutadiene/polystyrene block copolymers are preferred, particularly radial block copolymers, such as, for example, ~polystyrene/polybutadiene)4Si.
The polystyrene content of the binder or binder mixture of the elastomeric layer (c) is 10 to 35 percent by weight, preferably 15 to 30 percent by weight.
In addition, the block copolymers essential to the invention have a solution viscosity, measured as a 5.23%
soiution in toluene, of greater than or equal to 5 mm2is, particularly greater than or equal to 10 mm2/s, and a melt index, measured according to ASTM D 1238 P 5 kg/190C, of less than or equal to 10 g/10 min, particularly less than or equal to 2 g/10 min.
Particularly preferred binders for the elastomeric layer (c) are radial (polystyrene/polybutadiene~4Si blocX copolymers having a polystyrene content of 18 to 23 percent by weight, a solution viscosity of greater than or equal to 15 mm2/s and a melt index of less than or equal to 1.5 g/min.
A particularly advantageous embodiment of the present invention uses, in addition to the block copolymers described, a polymer having a turbidity of less than or equal to 20~, preferably less than or equal to 1~% measured accordin~ to ASTM D 1003 and a Rockwell hardness of greater than or equal to 50, preferably greater than or equal to 80 measured according to ASTM D
785. The content of this polymer in the elastomeric layer (c) is preferably between 1.5:1 to 1:1.5; 1:1 mixtures are especially preferred. Examples of such polymers are copolymers of acrylonitrile, butadiene, and methyl methacrylate or those also containing styrene.
The acrylonitrile content should be between 5 to 35 percent by weight, preferably between 5 to 20 percent by weight. In particular, a methyl methacrylate/acrylonitrile/butadiene/styrene tetrapolymer (96/9/14/31) with a turbidity of 10% and a Rockwell hardness of 103 is suitable.
Furthermore, conventional additives such as, for example, dyes, fillers, plasticizers, solvents, etc., can be used in the elastomeric layer.
The printing quality of aqueous and alcoholic printing plates may be improved by adding 5-30 percent by weight, preferably 15-25 percent by weight, of a polymer with the following structural unit A:
~CH2--CRl~
CO-O~CH2~m~CR2R3~nO-CO-CR4=CR5-COOH
wherein R1 is selected from the group consisting of H
and CH3, R2 and R3 can be the same or different and are ~5 selected from the group consist~ng of H and subst~tuted or unsubstituted alkyl or aryl groups, R4 and Rs can be ~ ~3 ~ 7 ~ J~,~ J
the same or different and are selected from the group consisting of H and substituted or unsubstituted alkyl groups, and m and n have values from 0 to 10, whereby the sum of m and n can equal 2 to 20.
The same effect can also be achieved by adding 5-30, preferably 15-25 percent by weight of a reaction product of an epoxide resin with an adduct, partially esterified with polyols, of unsaturated mono and/or polycarboxylic acids or their anhydridss with rosins.
The elastomeric layer (c) should be between 0.01 to 0.5 mm, preferably 0.025 to 0.12 mm, thick.
The layer can be applied by coating from solvents, such as toluene, acetone, methylene chloride, perchloroethylene, methyl ethyl ketone, methyl isobutyl ketone or mixtures, etc., or by extrusion coating directly onto the cover sheet ~d), for example, a polyethylene terephthalate sheet. Rather than dissolve the tetrapolymer with other components to prepare the coating solution for the elastomeric layer (c), a significant improvement in coating quality can be achieved by dissolving separately beforehand in the solvent and this solution is prefiltered and added to a solution of the usual coatin~ components.
The photopolymerizable layer (b) of the invention contains at least one elastomeric binder. Examples of suitable block copolymers are described in DE-C3 22 15-090 (U.S. Patent Nos. 4,323,636, 4,323,637, 4,369,296 and 4,g23,135), U.S. Patent No. 4,320,188, and U.S. Patent No. 4,162,919. Preferred block copolymers are of the A/B/A type having an elastomeric block, for example, polybutadiene or polyisoprene, between two thermoplastic blocks, for example, polystyrene.
Especially preferred are linear and radial block copolymers with polystyrene end blocks, such as, for example, polystyrene/polyisoprene/polystyrene, (polystyrene/polybutadiene)4Si or (polystyrene/polyisoprene)4Si.
The average molecular weight of the block copolymers should be between 80,000 and 300,000, and preferably between 100,000 and 250,000. The polystyrene portion should be 10 to 40 percent by weight, and preferably 15 to 30 percent by we:ight.
In addition, the photopolymerizable layer (b) contains at least one ethylenically unsaturated monomer addition-polymerizable by actinic radiation. This can include monomers with one ethylenically unsaturated group as well as those with several ethylenically unsaturated groups. The monomers can be used alone or in combination with one another. Monomer mixtures of monounsaturated acrylates and/or methacrylates and polyunsaturated acrylates and/or methacrylates are preferred. Such monomer mixtures are described in DE-C1 37 49 243 (U.S. Serial No. 07/274,464). Examples include octyl acrylate, isodecyl acrylate, isodecyl methacrylate, 2-hexyloxyethyl acrylate, 1,4-butanediol diacrylate, l,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, and trimethylol propane triacrylate.
The photopolymerizable layer ~b) also contains a photoinitiator or photoinitiator system. Suitable photoinitiators include, for example, ~-methyl benzoin, benzophenone, benzil dimethyl ketal or ethyl anthxaquinone/4,4'-bis-(dimethylamino)benzophenone. The photopolymerizable layer ~b) can also contain other additives, such as, for example, fillers, dyes, antioxidants and plas~icizers like those cited in EP-Bl 00 84 851 (U.S. Patent Nos. 4,4~7,759 and 4,460,675). Preferred plasticizers include those based on polystyrene or polybutadiene, at 0-30 percent by weight and having an average molecular weight between 1,000 and 10,000.
, ' -The photopolymerizable layer (b) generally contains 65-95 percent by weight binder, 5-30 percent by welght monomer or monomer mi~ture and 0.5 to 5 percent by weight initiator.
In practicing the inventiont suitable support layers include, for e~ample, alurninum, steel or synthetic resin sheets. Polyester sheets, optionally provided with an adhesive layer and/or an antihalation layer, are preferred. Polyethylene terephthalate sheets `
are particularly suitable.
The photopolymerizable printing elements of the invention are prepared preferably by the process described in EP-Bl 00 89 851 (U.S. Patent Nos. 4,427,759 and 4,960,675). A previously extruded photopolymerizable composition is fed into the nip of a calender and calendered between a support and a cover element consisting of a cover sheet (d) and the layer (c) of the invention. Thus, a photopolymerizable layer bounded on one side by the support and on the other side by the elastomeric layer ~c) of the cover element is formed.
The photopolymerizable printing element thus prepared is cooled and optionally pre exposed with actinic light thro~gh the support. The cover sheet is then removed, and an image-bearing txansparency is placed on the photopolymerizable printing element. The element is subsequently exposed to actinic light through the transparency. The non-crosslinked areas of the photopolymerizable layer (b) and of the elastomeric layer (c) are removed by washing of~ with a developer solvent. Organic solvents, such as chlorinated hydrocarbons, are particularly suitable developers. For example, l,1,1-trichloroethane, or saturated or aromatic hydrocarbons. The solvents disclosed in German Patent Application P 3B 28 551.7 are preferred. The solvent .
L.,~ ~ r.~
can be applied in any manner for development, for example, by drenching, immersing, spraying, or applying by roller. Removal of the non-crosslinked areas is facilitated by brushes. After development, the plate is dried at 40 to 75C. The resulting printing plate can be post-exposed and/or treated in any sequence, for example, with a solution containing a free halogen, to produce a non-tacky suLface.
The following examples serve to illustrate the 0 practice of the present invention.
EXAMPLES
In the following examples, percents and parts are by weight, unless otherwise stated.
COMPARATIVE EXAMPL~ 1 Polystyrene/polyisoprene/67.4%
polystyrene block copolymer 15% polystyrene, Brookfield viscosity 1600 mPa-s (25% in toluene) Methyl methacrylate/acrylo-31.3%
nitrile/butadiene/styrene tetrapolymer 46/9/14/31 Acid blue (C.I. 13390) 1.3%
A multilayer cover element was prepared as follows:
The dye and the tetrapolymer were kneaded together at 116C and then extruded and granulated. This mixture and the remaining components of elastomeric layer (c) were processed into a 15% solution in me~hylene chloride. The resulting coating solution was applied, by means of an extrusion slit coater with a 0.38 mm slit width, onto an uncoated polyethylene terephthalate support, as described in Example 1 of EP-B1 00 84 851 (U.S. Patent Nos. 4,427,759 and 4,460,675). The coated support was then dried, and provided with a silicone-f.l ~ 7 ~ ~g 1 l ~
coated polyethylene terephthalate protective layer. Thedry layer thickness was 0.051 mm.
A flexographic printing element was prepared as follows: The following photopolymerizable mixture was prepared, as in Example 1 of EP-B1 00 84 851, in a twin-crew extruder, extruded, and cale~dered between a polyethylene terephthalate support and the elastomeric layer (c) of the above-described cover element, after the polyethylene terephthalate protective layer was removed.
Par~s
PHOTOPOLYMERIZABLE PRINTING
PLATE FOR FLEXOGRAPHIC PRINTING
FIELD QF TH~ INVENTION
This invention relates ~o flexographic printing plates and more particularly to photopolymerizable printing elements comprising a photopolymerizable layer and an elastomeric layer ~oated thereon, wherein the elastomeric layer contains, as a binder, at least one or more thermoplastic, elastomeric block copolymers, made up of at least one polystyrene block and, at least one polybutadiene, polyethylene, and/or polypropylene block.
BACKGROUND OF THE INVENTION
Photopolymerizable recording materials are known for use in the manufacture of printing plates for flexographic printing, in which the printing plate is produced by exposing imagewise a light-sensitive layer and removing the unexposed areas of the layer. Examples of such recording materials are disclosed in DE-C 3 22 15 090 ~U.S. Patent Nos. 4,323,636, 4,323,637, 4,369,246 and 4,423,135), U.S. Patent No. 4,266,005, U.S. Patent No. 4,320,lR8, U.S. Patent No. 4,126,4~6, and U.S. Patent No. 4,430,417. Such photopolymerizable ~5 printing plates usually comprise a support, optionally an adhesive or other support coating, a photopolymerizable layer containing at least one polymeric binder, at least one ethylenically unsaturated monomer addition-polymerizable by actinic radiation, a photoinitiator or photoinitiator system, and a cover layer. Typically, a flexible, tear-resistant polymeric film is interposed between the photopolymerizable layer and the cover layer. The polymeric film serves as a protective layer in that it enables adhesion-free placement of the negative transparency for exposure of 6~ ~ ~ ' 1 Si, J ,Y
the printing plate. It also allows for good, bubble-free contact between the transparency and the printing plate. Examples of such protective layers are disclosed in U.S. Patent No. 9,423,135 and DE-C 23 37 6~5 tU.S.
Patent No. 3,895,949).
Photopolymerizable printing plates can be prepared from any one of several methods. However, a preferred method utili~es a calendering process whereby a previously extruded, photopolymerizable composition is fed into the nip of a calender and is calendered between a support and a cover element, thus forming between them a photopolymerizable layer.
Another method for preparing photopolymerizable printing plates is disclosed in EP-~1 00 84 851 ~U.S.
Patent Nos. 4,427,759 and 4,460,675) which teach a process for preparing a multilayer, photopolymerizable printing element comprising a flexible, tear-resistant polymer layer and a photopolymerizable layer, wherein between said layers is an elastomeric layer having an elastomeric binder, optionally a second binder, optionally a dye, optionally one or more monomers, and optionally a photoinitiator.
Positioning the image transparency on the elastomeric layer is possible provided the cover layer, which is removed before exposure, contains a special silicone layer which partially remains on the elastomeric layer. However, this process is bothersome and is feasible only for special cover layers and elastomeric intermediate layers. Moreover, the use of such silicone layers presents disadvantages in washoff development, because the silicones are insoluble in the developer solution and cause adhesion among the washoff brushes.
Another disadvantage of the photopolymerizable printing plates described above is that the flexi~le polymer layer required for adhesion-free, bubble-free placement of the negative complicates development of the exposed plates. The different solution behavior of the flexible polymer layer compared to the components of the photopolymerizable layer requires an additional development step, such as prior removal of the polymer layer, treatment with a special solvent, or additives in the actual developer solution. Many of these protective layers also swell in the developer solvent and can be removed only by intensive mechanical treatment.
In addition, each printing plate requires a polymeric protective layer coordinated specifically with its photopolymerizable layer. Thus, the composition of the polymer layer must be adapted to each photopolymerizable printing plate. This generates significant development and storage costs for the various types of layers. For this reason, and because of the additional process steps required in making and coating the polymer layer onto the photopolymerizable layer, production costs for printing plates are increased and the entire production process becomes more time-consuming. Furthermore, the basic incompatibility of the usual protective layers of polyamide films and the elastomeric block copolymers frequently employed as 2S binders in flexographic plates leads to permanent problems of delamination between the protective layer and the photopolymerizable layer.
Accordingly, the object of the present invention is to eliminate the above-cited d~fficultieq and disadvan~ages and make available a photopolymerizable printing plate whose surface is not tacky, so that direct placement of an image transparency on the printing plate is possible without damaging or spotting the transparency. At the same time, good bubble-free contact must be assured between the image transparency r~ ;~ 3 ~
and printing plate. The printing plate should also be easier and less expensive to produce and process.
Furthermore, conventional washoff development with current solvents should be possible without additives.
The ozone stability of the printing plates should also be increased. Concurrently, oth~er properties of the photopolymerizable printing plates should not be affected adversely. For example, a decrease in photosensitivity should be avoided and the flexographic printing plates should not swell as a result of the printing inks, because such swelling causes undesirable dot growth and thus, flawed printing.
~ urprisingly, the aforementioned objectives are achieved by using a photopolymerizable printing element comprising ~a) a support, (b) a photopolymerizable layer containing at least one elastomeric binder, at least one ethylenically unsaturated monomer addition-polymerizable by actinic radiation, a photoinitiator or photoinitiator system, ~c) an elastomeric layer containing at least one thermoplastic, elastomeric block copolymer, and (d) a cover sheet.
SUMMARY OE THE INVEN~IQ~
The invention relates to a photopolymerizable printing element comprising:
(a) a support;
(b) a photopolymerizable layer having at least one elastomeric binder, at least one ethylenically unsaturated monomer addition-polymerizable by actinic radiation, and a photoinitiator or photoinitiator system;
(c) an elastomeric layer having at least one thermoplastic, elastomeric block copolymer; and (~) a cover sheet, wherein the elastomeric layer (c) further comprises as a binder, one or more thermoplastic, elastomeric block -copolymers, made up o~ at least one polystyrene block and at least one polybutadiene, polyethylene, and/or polypropylene block, the binder or binder mixture having a polystyrene content of 10 to 35 percent by weight, a solution viscosity for a 5.23~ solution in toluene greater than or equal to 5 mm2/s, and a melt index less than or equal to 10 g/10 min.
Another aspect of the invention relates to a process for preparing a photopolymerizable printing element.
A further aspect of the invention relates to a process for preparing a coating solution for the elastomeric layer (c) of the photopolymerizable printing element.
The invention also relates to a process for preparing flexographic printing plates.
DETAI~ED ~SÇRIPTION OF THE INVENTION
The photopolymerizable printing element of the invention utilizes an elastomeric layer (c1 containing a binder of one or more thermoplastic, elastomeric block copolymers made up of at least one polystyrene block and at least one polybutadiene, polyethylene, and/or polypropylene block, wherein the polystyrene content of the binder or binder mixture is 10 to 35 percent by weight, the solution viscosity of the block copolymer for a 5.23% solution in toluene is greater than or equal to 5 mm2/s, and the melt index measured according to ASTM D 1238 P is less than or equal to 10 g/10 min.
The elastomeric layer adheres well to the photopolymerizable layer so that delamination problems do not ar~se. Printing plates for flexographic printing prepared from the invention show good printing properties compared to plates prepared from conventional printing elements. The surface of the printing plate is resistant to flexographic printing inks, even in large r~
printing runs. Surface swelling is not observed and print quality is uniformly good.
A particular advantage is that the printing plates of the invention show good flexibility. In addition, the surface is not brittle, and the printing plates do not crease under high bearing pressure.
The use of only one developer solvent enables simpler and more reliable quality control in washoff development of the exposed printing plates.
Furthermore, the washoff rate is increased compared to conventional printing plates that have a polyamide layer.
The thermoplastic, elastomeric block copolymers in the elastomeric layer (c) of the claimed invention are made up of at least one polystyrene block and at least one polybutadiene, polyethylene, and/or polypropylene block. Polystyrene/polybutadiene or polystyrene/polybutadiene/polystyrene block copolymers are preferred, particularly radial block copolymers, such as, for example, ~polystyrene/polybutadiene)4Si.
The polystyrene content of the binder or binder mixture of the elastomeric layer (c) is 10 to 35 percent by weight, preferably 15 to 30 percent by weight.
In addition, the block copolymers essential to the invention have a solution viscosity, measured as a 5.23%
soiution in toluene, of greater than or equal to 5 mm2is, particularly greater than or equal to 10 mm2/s, and a melt index, measured according to ASTM D 1238 P 5 kg/190C, of less than or equal to 10 g/10 min, particularly less than or equal to 2 g/10 min.
Particularly preferred binders for the elastomeric layer (c) are radial (polystyrene/polybutadiene~4Si blocX copolymers having a polystyrene content of 18 to 23 percent by weight, a solution viscosity of greater than or equal to 15 mm2/s and a melt index of less than or equal to 1.5 g/min.
A particularly advantageous embodiment of the present invention uses, in addition to the block copolymers described, a polymer having a turbidity of less than or equal to 20~, preferably less than or equal to 1~% measured accordin~ to ASTM D 1003 and a Rockwell hardness of greater than or equal to 50, preferably greater than or equal to 80 measured according to ASTM D
785. The content of this polymer in the elastomeric layer (c) is preferably between 1.5:1 to 1:1.5; 1:1 mixtures are especially preferred. Examples of such polymers are copolymers of acrylonitrile, butadiene, and methyl methacrylate or those also containing styrene.
The acrylonitrile content should be between 5 to 35 percent by weight, preferably between 5 to 20 percent by weight. In particular, a methyl methacrylate/acrylonitrile/butadiene/styrene tetrapolymer (96/9/14/31) with a turbidity of 10% and a Rockwell hardness of 103 is suitable.
Furthermore, conventional additives such as, for example, dyes, fillers, plasticizers, solvents, etc., can be used in the elastomeric layer.
The printing quality of aqueous and alcoholic printing plates may be improved by adding 5-30 percent by weight, preferably 15-25 percent by weight, of a polymer with the following structural unit A:
~CH2--CRl~
CO-O~CH2~m~CR2R3~nO-CO-CR4=CR5-COOH
wherein R1 is selected from the group consisting of H
and CH3, R2 and R3 can be the same or different and are ~5 selected from the group consist~ng of H and subst~tuted or unsubstituted alkyl or aryl groups, R4 and Rs can be ~ ~3 ~ 7 ~ J~,~ J
the same or different and are selected from the group consisting of H and substituted or unsubstituted alkyl groups, and m and n have values from 0 to 10, whereby the sum of m and n can equal 2 to 20.
The same effect can also be achieved by adding 5-30, preferably 15-25 percent by weight of a reaction product of an epoxide resin with an adduct, partially esterified with polyols, of unsaturated mono and/or polycarboxylic acids or their anhydridss with rosins.
The elastomeric layer (c) should be between 0.01 to 0.5 mm, preferably 0.025 to 0.12 mm, thick.
The layer can be applied by coating from solvents, such as toluene, acetone, methylene chloride, perchloroethylene, methyl ethyl ketone, methyl isobutyl ketone or mixtures, etc., or by extrusion coating directly onto the cover sheet ~d), for example, a polyethylene terephthalate sheet. Rather than dissolve the tetrapolymer with other components to prepare the coating solution for the elastomeric layer (c), a significant improvement in coating quality can be achieved by dissolving separately beforehand in the solvent and this solution is prefiltered and added to a solution of the usual coatin~ components.
The photopolymerizable layer (b) of the invention contains at least one elastomeric binder. Examples of suitable block copolymers are described in DE-C3 22 15-090 (U.S. Patent Nos. 4,323,636, 4,323,637, 4,369,296 and 4,g23,135), U.S. Patent No. 4,320,188, and U.S. Patent No. 4,162,919. Preferred block copolymers are of the A/B/A type having an elastomeric block, for example, polybutadiene or polyisoprene, between two thermoplastic blocks, for example, polystyrene.
Especially preferred are linear and radial block copolymers with polystyrene end blocks, such as, for example, polystyrene/polyisoprene/polystyrene, (polystyrene/polybutadiene)4Si or (polystyrene/polyisoprene)4Si.
The average molecular weight of the block copolymers should be between 80,000 and 300,000, and preferably between 100,000 and 250,000. The polystyrene portion should be 10 to 40 percent by weight, and preferably 15 to 30 percent by we:ight.
In addition, the photopolymerizable layer (b) contains at least one ethylenically unsaturated monomer addition-polymerizable by actinic radiation. This can include monomers with one ethylenically unsaturated group as well as those with several ethylenically unsaturated groups. The monomers can be used alone or in combination with one another. Monomer mixtures of monounsaturated acrylates and/or methacrylates and polyunsaturated acrylates and/or methacrylates are preferred. Such monomer mixtures are described in DE-C1 37 49 243 (U.S. Serial No. 07/274,464). Examples include octyl acrylate, isodecyl acrylate, isodecyl methacrylate, 2-hexyloxyethyl acrylate, 1,4-butanediol diacrylate, l,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, and trimethylol propane triacrylate.
The photopolymerizable layer ~b) also contains a photoinitiator or photoinitiator system. Suitable photoinitiators include, for example, ~-methyl benzoin, benzophenone, benzil dimethyl ketal or ethyl anthxaquinone/4,4'-bis-(dimethylamino)benzophenone. The photopolymerizable layer ~b) can also contain other additives, such as, for example, fillers, dyes, antioxidants and plas~icizers like those cited in EP-Bl 00 84 851 (U.S. Patent Nos. 4,4~7,759 and 4,460,675). Preferred plasticizers include those based on polystyrene or polybutadiene, at 0-30 percent by weight and having an average molecular weight between 1,000 and 10,000.
, ' -The photopolymerizable layer (b) generally contains 65-95 percent by weight binder, 5-30 percent by welght monomer or monomer mi~ture and 0.5 to 5 percent by weight initiator.
In practicing the inventiont suitable support layers include, for e~ample, alurninum, steel or synthetic resin sheets. Polyester sheets, optionally provided with an adhesive layer and/or an antihalation layer, are preferred. Polyethylene terephthalate sheets `
are particularly suitable.
The photopolymerizable printing elements of the invention are prepared preferably by the process described in EP-Bl 00 89 851 (U.S. Patent Nos. 4,427,759 and 4,960,675). A previously extruded photopolymerizable composition is fed into the nip of a calender and calendered between a support and a cover element consisting of a cover sheet (d) and the layer (c) of the invention. Thus, a photopolymerizable layer bounded on one side by the support and on the other side by the elastomeric layer ~c) of the cover element is formed.
The photopolymerizable printing element thus prepared is cooled and optionally pre exposed with actinic light thro~gh the support. The cover sheet is then removed, and an image-bearing txansparency is placed on the photopolymerizable printing element. The element is subsequently exposed to actinic light through the transparency. The non-crosslinked areas of the photopolymerizable layer (b) and of the elastomeric layer (c) are removed by washing of~ with a developer solvent. Organic solvents, such as chlorinated hydrocarbons, are particularly suitable developers. For example, l,1,1-trichloroethane, or saturated or aromatic hydrocarbons. The solvents disclosed in German Patent Application P 3B 28 551.7 are preferred. The solvent .
L.,~ ~ r.~
can be applied in any manner for development, for example, by drenching, immersing, spraying, or applying by roller. Removal of the non-crosslinked areas is facilitated by brushes. After development, the plate is dried at 40 to 75C. The resulting printing plate can be post-exposed and/or treated in any sequence, for example, with a solution containing a free halogen, to produce a non-tacky suLface.
The following examples serve to illustrate the 0 practice of the present invention.
EXAMPLES
In the following examples, percents and parts are by weight, unless otherwise stated.
COMPARATIVE EXAMPL~ 1 Polystyrene/polyisoprene/67.4%
polystyrene block copolymer 15% polystyrene, Brookfield viscosity 1600 mPa-s (25% in toluene) Methyl methacrylate/acrylo-31.3%
nitrile/butadiene/styrene tetrapolymer 46/9/14/31 Acid blue (C.I. 13390) 1.3%
A multilayer cover element was prepared as follows:
The dye and the tetrapolymer were kneaded together at 116C and then extruded and granulated. This mixture and the remaining components of elastomeric layer (c) were processed into a 15% solution in me~hylene chloride. The resulting coating solution was applied, by means of an extrusion slit coater with a 0.38 mm slit width, onto an uncoated polyethylene terephthalate support, as described in Example 1 of EP-B1 00 84 851 (U.S. Patent Nos. 4,427,759 and 4,460,675). The coated support was then dried, and provided with a silicone-f.l ~ 7 ~ ~g 1 l ~
coated polyethylene terephthalate protective layer. Thedry layer thickness was 0.051 mm.
A flexographic printing element was prepared as follows: The following photopolymerizable mixture was prepared, as in Example 1 of EP-B1 00 84 851, in a twin-crew extruder, extruded, and cale~dered between a polyethylene terephthalate support and the elastomeric layer (c) of the above-described cover element, after the polyethylene terephthalate protective layer was removed.
Par~s
2,2-dimethoxy-2-phenyl acetophenone 1.4 Hexamethylene glycol diacrylate 5.3 Hexamethylene glycol dimethacrylate 3.7 2,6-di-tert-butyl-p-cresol 0.166 Hydroquinone 0.001 Red dye ~C.I. 109) 0.003 Hydroxyethyl methacrylate 0.13 Polystyrene/polyisoprene/polystyrene 82.3 block copolymer (15~ polystyrene molecular weight 150,000) a-methyl styrene/vinyl toluene resin 6 Microcrystalline hydrocarbon wax After cooling, overall backside exposure through the support, and removal of the polyethylene terephthalate cover layer, an image-bearing transparency was placed on the printing plate surface, and the printing plate was exposed through the transparency with actinic radiation for 6 minutes. The image transparency could be removed only with great difficulty from the tacky surface of the printing plate; large areas of the surface layer remained adhered to the image transparency, which became useless. Printing tests could not be conducted with this printing plate, because the printing surface was too severely damaged. The photopolymerized printing plate was developed by washoff with tetrachloroethylene, removing the unexposed areas of the photopolymerizable layer (b) and of the elastomeric layer (c). As in Example 1 of EP-Bl 00 84 851, the flexographic prlnting plate was then dried, treated with aqueous hypochlorite solution and post-exposed.
Composition of elastomeric layer c) Radial (polystyrene/polybutadiene)4Si 98.2%
block copolymer solution viscosity 19 mm2/s ~5.23~ in toluene), melt index <0.5 g/10 min - ~according to ASTM D 1238 P) A copper phthalocyanine dispersed 1.2 in didecyl phthalate (C.I. 74160) A 17% solution in methylene chloride was processed as in Example 1 to make elastomeric layer (c). A
printing plate was prepared and processed as described in Example 1. Photosensitivity, exposure latitude and development behavior corresponded to current state-of-the-art printing plates. The printing plate was outstanding for improved`stability to ozone. The surface of the photopolymerizable printing plate was not tacky, so that the exposure transparency could be removed without difficulty after exposure. It was completely undamaged and clean, and suitable for repeat use. The surface of the resulting flexographic printing plate was completely intact, showed no crease formation and no swelling with the printing inks utilized.
7 ~ f'.~
E~:~
Composition of ela~tomeric layer c) Radial (polystyrene/polybutadiene)4Si 50%
block copolymer 20~ polystyrene, solution viscosity 19 mm2/s ~5.23%
in toluene), melt index <0.5 g/10 min (according to ASTM D 1238 P) Methyl methacrylate/acrylonitrilet 49%
butadiene/styrene tetrapolymer, ~6/9/14/31, turbidity 10~ (according to ASTM D 1003), Rockwell hardness 103 (according to ASTM 785) A copper phthalocyanine dispersed 1%
in didecylphthalate 15 The tetrapolymer was dissolved in toluene/methyl ethyl ketone (4:1) and the solution was filtered. A 20%
coating solution was prepared from this solution and the remaining components. Preparation of the elastomeric layer and all other processing steps followed as in Example 2. Photosensitivity, exposure latitude, and development behavior corresponded to current state-of-the-art printing plates. The printing plate was outstanding for improved stability to ozone. The surface of the photopolymerizable printing plate was not tacky, so that the exposure transparency could be removed without difficulty after exposure. It was completely undamaged and clean, and suitable for repeat use. The surface of the resulting flexographic printing plate was completely intact, showed no crease formation and no swelling with the printing inks utilized.
~AMPLE 4 ~nmnosition of~ stomeric la~er ~L
Radial ~polystyrene/polybutadiene)4Si 45.2 block copolymer 20% polystyrene, solution viscosity 19 mm2/s (5.23% in toluene), melt index ~0.5 g/10 min (accordin~ to AST~ D 1238 P) Methyl methacrylate/acrylonitr:ile/ 45.2 butadiene/styrene 46/9/14/31, turbidity 10% (according to ~STM D 1003), Rockwell hardness 103 (according to ASTM 785)~
A copper phthalocyanine dispersed 0.6%
in didecyl phthalate (C.I. 74160) Acrylic acid-modified rosin 5.0%
partially esterified with glycerin (acid number 220-250, viscosity about 17 mPa-s at 20C, 50% in ethanol) Bisphenol A/epichlorohydrin 4.0%
epoxide resin [epoxide equivalent weight 182-199 g, ~iscosity 9-14 Pa-s at 25C (according to ASTM D 495)]
The preparation of the coating solution, of the elastomeric layer and all other processing steps followed as in Example 2. Photosensitivity, exposure latitude, and development behavior corresponded to current state-of-the-art printing plates. The printing plate was outstanding for improved stability to ozone.
The surface of the photopolymerizable printing plate was not tacky, so that the exposure transparency could be removed without difficulty after exposure. It was completely undamaged and clean, and suitable for repeat use. The surface of the resulting fléxographic printing 2 ~ ~ 7 ~ . J r.J
plate was completely intact, showed no crease formation and no swelling with the printing inks utilized.
Composition of elastomeric layer c) Radial (polystyrene/polybutadiene)4Si 98.2%
block copolymer solution viscosity 19 mm2/s ~5.23~ in toluene), melt index <0.5 g/10 min - ~according to ASTM D 1238 P) A copper phthalocyanine dispersed 1.2 in didecyl phthalate (C.I. 74160) A 17% solution in methylene chloride was processed as in Example 1 to make elastomeric layer (c). A
printing plate was prepared and processed as described in Example 1. Photosensitivity, exposure latitude and development behavior corresponded to current state-of-the-art printing plates. The printing plate was outstanding for improved`stability to ozone. The surface of the photopolymerizable printing plate was not tacky, so that the exposure transparency could be removed without difficulty after exposure. It was completely undamaged and clean, and suitable for repeat use. The surface of the resulting flexographic printing plate was completely intact, showed no crease formation and no swelling with the printing inks utilized.
7 ~ f'.~
E~:~
Composition of ela~tomeric layer c) Radial (polystyrene/polybutadiene)4Si 50%
block copolymer 20~ polystyrene, solution viscosity 19 mm2/s ~5.23%
in toluene), melt index <0.5 g/10 min (according to ASTM D 1238 P) Methyl methacrylate/acrylonitrilet 49%
butadiene/styrene tetrapolymer, ~6/9/14/31, turbidity 10~ (according to ASTM D 1003), Rockwell hardness 103 (according to ASTM 785) A copper phthalocyanine dispersed 1%
in didecylphthalate 15 The tetrapolymer was dissolved in toluene/methyl ethyl ketone (4:1) and the solution was filtered. A 20%
coating solution was prepared from this solution and the remaining components. Preparation of the elastomeric layer and all other processing steps followed as in Example 2. Photosensitivity, exposure latitude, and development behavior corresponded to current state-of-the-art printing plates. The printing plate was outstanding for improved stability to ozone. The surface of the photopolymerizable printing plate was not tacky, so that the exposure transparency could be removed without difficulty after exposure. It was completely undamaged and clean, and suitable for repeat use. The surface of the resulting flexographic printing plate was completely intact, showed no crease formation and no swelling with the printing inks utilized.
~AMPLE 4 ~nmnosition of~ stomeric la~er ~L
Radial ~polystyrene/polybutadiene)4Si 45.2 block copolymer 20% polystyrene, solution viscosity 19 mm2/s (5.23% in toluene), melt index ~0.5 g/10 min (accordin~ to AST~ D 1238 P) Methyl methacrylate/acrylonitr:ile/ 45.2 butadiene/styrene 46/9/14/31, turbidity 10% (according to ~STM D 1003), Rockwell hardness 103 (according to ASTM 785)~
A copper phthalocyanine dispersed 0.6%
in didecyl phthalate (C.I. 74160) Acrylic acid-modified rosin 5.0%
partially esterified with glycerin (acid number 220-250, viscosity about 17 mPa-s at 20C, 50% in ethanol) Bisphenol A/epichlorohydrin 4.0%
epoxide resin [epoxide equivalent weight 182-199 g, ~iscosity 9-14 Pa-s at 25C (according to ASTM D 495)]
The preparation of the coating solution, of the elastomeric layer and all other processing steps followed as in Example 2. Photosensitivity, exposure latitude, and development behavior corresponded to current state-of-the-art printing plates. The printing plate was outstanding for improved stability to ozone.
The surface of the photopolymerizable printing plate was not tacky, so that the exposure transparency could be removed without difficulty after exposure. It was completely undamaged and clean, and suitable for repeat use. The surface of the resulting fléxographic printing 2 ~ ~ 7 ~ . J r.J
plate was completely intact, showed no crease formation and no swelling with the printing inks utilized.
Claims (8)
1. A photopolymerizable printing element comprising:
(a) a support;
(b) a photopolymerizable layer having at least one elastomeric binder, at least one ethylenically unsaturated monomer addition-polymerizable by actinic radiation, and a photoinitiator or photoinitiator system;
(c) an elastomeric layer having at least one thermoplastic, elastomeric block copolymer; and (d) a cover sheet, wherein the elastomeric layer (c) further comprises as a binder, one or more thermoplastic, elastomeric block copolymers, made up of at least one polystyrene block and at least one polybutadiene, polyethylene and/or polypropylene block, the binder or binder mixture having a polystyrene content of 10 to 35 percent by weight, a solution viscosity for a 5.23% solution in toluene greater than or equal to 5 mm2/s, and a melt index less than or equal to 10 g/10 min.
(a) a support;
(b) a photopolymerizable layer having at least one elastomeric binder, at least one ethylenically unsaturated monomer addition-polymerizable by actinic radiation, and a photoinitiator or photoinitiator system;
(c) an elastomeric layer having at least one thermoplastic, elastomeric block copolymer; and (d) a cover sheet, wherein the elastomeric layer (c) further comprises as a binder, one or more thermoplastic, elastomeric block copolymers, made up of at least one polystyrene block and at least one polybutadiene, polyethylene and/or polypropylene block, the binder or binder mixture having a polystyrene content of 10 to 35 percent by weight, a solution viscosity for a 5.23% solution in toluene greater than or equal to 5 mm2/s, and a melt index less than or equal to 10 g/10 min.
2. The photopolymerizable printing element of Claim 1, wherein the elastomeric layer (c) contains a polystyrene/polybutadiene or polystyrene/
polybutadiene/polystyrene block copolymer having a polystyrene content of 15 to 30 percent by weight, a solution viscosity of greater than or equal to 10 mm2/s, and a melt index less than or equal to 2 g/10 min.
polybutadiene/polystyrene block copolymer having a polystyrene content of 15 to 30 percent by weight, a solution viscosity of greater than or equal to 10 mm2/s, and a melt index less than or equal to 2 g/10 min.
3. The photopolymerizable printing element of Claim 1 or 2, wherein the elastomeric layer (c) contains a radial (polystyrene/polybutadiene)4Si block copolymer having a polystyrene content of 18 to 23 percent by weight, a solution viscosity of greater than or equal to 15 mm2/s, and a melt index less than or equal to 1.5 g/10 min.
17 9. The photopolymerizable printing element of Claim 1 or 2, wherein the elastomeric layer (c) contains 30 to 70 percent by weight of a polymer having a turbidity of less than or equal to 20% and a Rockwell hardness of greater than or equal to 50.
5. The photopolymerizable printing element of Claim 4, wherein the elastomeric layer (c) contains 40 to 60 percent by weight of a polymer having a turbidity of less than or equal to 12% and a Rockwell hardness of greater than or equal to 80.
6. A process for preparing a coating solution for the elastomeric layer of Claim 5 comprising:
(a) dissolving the polymer in a solvent;
(b) filtering the polymer/solvent solution, and (c) adding the remaining components to the polymer solution of (b).
(a) dissolving the polymer in a solvent;
(b) filtering the polymer/solvent solution, and (c) adding the remaining components to the polymer solution of (b).
7. A process for preparing photopolymerizable printing elements comprising feeding into the nip of a calender a photopolymerizable composition containing at least one elastomeric binder, at least one ethylenically unsaturated monomer addition-polymerizable by actinic radiation and a photoinitiator or a photoinitiator system, calendering the composition between a support (a) and a multilayer cover element to form the photopolymerizable layer (b) between them, wherein the multilayer cover element comprises an elastomeric layer (c) containing at least one thermoplastic, elastomeric block copolymer and a cover sheet (d), wherein the elastomeric layer (c) further comprises, as a binder, one or more thermoplastic, elastomeric block copolymers made up of at least one polystyrene block and at least one polybutadiene, polyethylene, and/or polypropylene block, wherein the polystyrene content of the binder or the binder mixture is 10 to 35 percent by weight, the solution viscosity of the block copolymers for a 5.23%
solution in toluene is greater than or equal to 5 mm2/s, and the melt index is less than or equal to 10 g/10 min.
solution in toluene is greater than or equal to 5 mm2/s, and the melt index is less than or equal to 10 g/10 min.
8. A process for preparing flexographic printing plates comprising:
(a) exposing imagewise the photopolymerizable printing element of Claim 1; and (b) removing the unexposed areas of the photopolymerizable layer (b) and of the elastomeric layer (c) by washoff with developer solvents.
(a) exposing imagewise the photopolymerizable printing element of Claim 1; and (b) removing the unexposed areas of the photopolymerizable layer (b) and of the elastomeric layer (c) by washoff with developer solvents.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4022978.5 | 1990-07-19 | ||
| DE4022978A DE4022978C1 (en) | 1990-07-19 | 1990-07-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2047302A1 true CA2047302A1 (en) | 1992-01-20 |
Family
ID=6410598
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002047302A Abandoned CA2047302A1 (en) | 1990-07-19 | 1991-07-17 | Photopolymerizable printing plate for flexographic printing |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0467136B1 (en) |
| JP (1) | JP2607775B2 (en) |
| CA (1) | CA2047302A1 (en) |
| DE (2) | DE4022978C1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6355395B1 (en) | 1998-12-23 | 2002-03-12 | Basf Drucksysteme Gmbh | Photopolymerizable printing plates with top layer for producing relief printing plates |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1031303A (en) * | 1994-09-29 | 1998-02-03 | Nippon Zeon Co Ltd | Photosensitive composition and photosensitive rubber plate |
| DE19703917A1 (en) * | 1997-02-03 | 1998-08-06 | Du Pont Deutschland | Flexographic printing forms for corrugated cardboard printing |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1099435A (en) * | 1971-04-01 | 1981-04-14 | Gwendyline Y. Y. T. Chen | Photosensitive block copolymer composition and elements |
| US4427759A (en) * | 1982-01-21 | 1984-01-24 | E. I. Du Pont De Nemours And Company | Process for preparing an overcoated photopolymer printing plate |
| JPS60181740A (en) * | 1984-02-28 | 1985-09-17 | Asahi Chem Ind Co Ltd | Photosensitive elastomer composition for flexographic printing |
| US4622088A (en) * | 1984-12-18 | 1986-11-11 | E. I. Du Pont De Nemours And Company | Process for preparing photopolymer flexographic element with melt extrusion coated elastomeric surface layer |
| DE3744243C2 (en) * | 1987-12-24 | 1995-12-07 | Du Pont Deutschland | Improved photopolymerizable recording materials |
-
1990
- 1990-07-19 DE DE4022978A patent/DE4022978C1/de not_active Expired - Fee Related
-
1991
- 1991-06-29 DE DE59108907T patent/DE59108907D1/en not_active Expired - Lifetime
- 1991-06-29 EP EP91110805A patent/EP0467136B1/en not_active Expired - Lifetime
- 1991-07-17 CA CA002047302A patent/CA2047302A1/en not_active Abandoned
- 1991-07-19 JP JP3179243A patent/JP2607775B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6355395B1 (en) | 1998-12-23 | 2002-03-12 | Basf Drucksysteme Gmbh | Photopolymerizable printing plates with top layer for producing relief printing plates |
Also Published As
| Publication number | Publication date |
|---|---|
| DE59108907D1 (en) | 1998-01-29 |
| JPH04271351A (en) | 1992-09-28 |
| JP2607775B2 (en) | 1997-05-07 |
| EP0467136A1 (en) | 1992-01-22 |
| DE4022978C1 (en) | 1991-08-08 |
| EP0467136B1 (en) | 1997-12-17 |
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