Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C1/00—Forme preparation
  • B41C1/006—Forme preparation the relief or intaglio pattern being obtained by abrasive means, e.g. by sandblasting
• • 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
  • G03F7/20—Exposure; Apparatus therefor
  • G03F7/2002—Exposure; Apparatus therefor with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image
  • G03F7/2014—Contact or film exposure of light sensitive plates such as lithographic plates or circuit boards, e.g. in a vacuum frame
  • G03F7/2016—Contact mask being integral part of the photosensitive element and subject to destructive removal during post-exposure processing
  • G03F7/202—Masking pattern being obtained by thermal means, e.g. laser ablation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C1/00—Forme preparation
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/02—Printing inks
  • C09D11/10—Printing inks based on artificial resins
  • C09D11/101—Inks specially adapted for printing processes involving curing by wave energy or particle radiation, e.g. with UV-curing following the printing
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/50—Sympathetic, colour changing or similar inks
• • 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

Definitions

• Stolt et al. in US Patent Publication 2010/0143841 disclose a method to increase solid ink density printing capability for a relief printing form through digital patterning of image areas of the precursor.
• Stolt et al. disclose applying a pattern to all image feature areas in halftone data that is used to produce an image mask, which is then used to convert the precursor into a relief printing form.
• the printing form carries a relief image that resolves the pattern in the surface of the relief features, and provides solid relief features to maintain or increase printed solid ink densities.
• a problem with this method is that it is still essentially an analog workflow since a phototool is created that is then contacted by lamination with the photopolymerizable layer of the precursor.
• an infrared ablation layer that is ablatable by infrared radiation and opaque to non-infrared actinic radiation, the infrared ablation layer comprising (i) at least one infrared absorbing material; (ii) a radiation opaque material, wherein (i) and (ii) can be the same or different; and (iii) at least one second binder; and, a pattern layer disposed between the photopolymerizable layer and the infrared laser radiation ablation layer, wherein the pattern layer comprises a plurality of features in which each feature has an area between 5 to 750 square microns and is composed of an ink that is opaque to actinic radiation and transparent to infrared radiation, and further wherein the mask comprises actinic radiation opaque areas and open areas, and the features of the pattern layer remain in the open areas;
• FIG. 5a through 5e are reproductions of a microscope image of a printing surface of each Test Relief Printing Plate that were prepared from Test Printing Plate Precursor of Tests 1 through 5, respectively, as described in Example 1. All microscope images were taken with a Zeiss Axio Observer Z1 M microscope, in reflectance mode.
• Print microcell pattern refers to a composite of features that together form a pattern that is printed for inclusion at some stage of production of the photosensitive element of the present invention.
• a printed microcell pattern in which a plurality of features is printed with a particular ink for incorporation into a photosensitive element is distinguished from a microcell pattern that is
• photosensitive encompasses any system in which the photosensitive composition is capable of initiating a reaction or reactions, particularly photochemical reactions, upon response to actinic radiation.
• chain propagated polymerization of a monomer and/or oligomer is induced by either a condensation mechanism or by free radical addition polymerization. While all photopolymerizable mechanisms are contemplated, the compositions and processes of this invention will be described in the context of free-radical initiated addition polymerization of monomers and/or oligomers having one or more terminal ethylenically unsaturated groups.
• FIG. 1 depicts one embodiment of a photosensitive element 10 of the present invention that is a printing form precursor 10 used for preparing printing forms.
• the printing form precursor 10 includes a support 12, at least one layer of a photosensitive composition 14 that is on or adjacent the optional support 12, a digital layer 16 adjacent to a side 18 of the photosensitive layer 14 that is opposite the support 12, and one embodiment cell pattern layer 20 that is disposed between the photosensitive layer 14 and the digital layer 16.
• the photosensitive layer 14 is a layer of a photopolymerizable composition.
• the cell pattern layer 20 In order to render the cell pattern layer 20 useful for its intended purpose which is to create a pattern of very small image elements, so-called microcells, on a print surface of a relief printing form, the cell pattern layer that is a printed microcell pattern is oriented between a source of actinic radiation and a surface of the photosensitive layer that will ultimately become the printing surface of the resulting relief printing form. In most embodiments of the photosensitive element, the cell pattern layer is a printed microcell pattern that is disposed between the digital layer and the photopolymerizable layer.
• the cell pattern layer is a printed microcell pattern that is disposed on a side of the digital layer that is opposite the photopolymerizable layer, i.e., the digital layer is between the photopolymerizable layer and the cell pattern layer.
• the cell pattern layer is a printed microcell pattern is disposed in or on a separate cover element, such as a barrier layer coversheet,
• the cell pattern layer 20 includes a plurality of features each having an area of 5 to 750 square microns and separated from adjacent features with spacing on average of 5 to 30 micron as determined by a geometric centroid of each feature.
• Each feature of the pattern is a two-dimensional shape (based on a planar view) that is not limited, and can have a convex perimeter, or a non- convex perimeter.
• Non-limiting examples of features with two-dimensional shapes having a convex perimeter include circles, squares, and rectangles.
• the plurality of features can be applied directly or indirectly to a layer of the photosensitive element to form the cell pattern layer by printing with the ink that in most embodiments is opaque to actinic radiation and transparent to infrared radiation.
• the ink that is used to print the features of the cell pattern layer is transparent to, i.e., does not absorb, infrared radiation, particularly at the wavelength/s of infrared laser radiation that is used to form the mask of the digital layer, so that the features of the cell pattern layer are not removed by, or disturbed, or modified by, the impinging laser radiation.
• digital methods use the laser radiation to create from the digital layer a mask image that can be formed in situ on or disposed above the photopolymerizable layer of the printing form precursor.
• digital methods use the laser radiation to create from the digital layer a mask that is formed on a digital element that is separate from the photopolymerizable layer, and subsequently the digital element with the mask is applied to the photopolymerizable layer forming the printing form precursor.
• the photosensitive element will not initially include the digital layer.
• a separate element bearing the digital layer will form an assemblage with the photosensitive element (that in this embodiment includes primarily the photopolymerizable layer and the optional support) such that the digital layer is adjacent the surface of the photosensitive element opposite the support, which is typically is the photopolymerizable layer. If present, a coversheet associated with the photosensitive element typically is removed prior to forming the assemblage.
• the cell pattern layer is printed onto the surface of the photopolymerizable layer that is opposite the support.
• the separate element includes at least the digital layer on a polymeric film, and may include one or more other layers, such as ejection layers or heating layers, to aid in the digital exposure process.
• the photosensitive element includes film (of separate element), the cell pattern layer, the digital layer forming a mask, the photopolymerizable layer, and optional support.
• the film of the separate element may remain with the assemblage, and be present during imagewise exposure of the photosensitive layer.
• Materials constituting the digital layer and structures incorporating the digital layer are not particularly limited, provided that the digital layer can be imagewise exposed to form the in-situ mask on or adjacent the
• polypropylene oxide ethylcellulose, hydroxyethyl cellulose, cellulose acetate butyrate, ethylene-propylene-diene terpolymers, copolymers of ethylene and vinyl acetate, copolymers of vinyl acetate and vinyl alcohol, copolymers of vinyl acetate and pyrrolidone, polyvinyl acetate, polyethylene wax, polyacetal, polybutyral, polyalkylene, polycarbonates, polyester elastomer, copolymers of vinyl chloride and vinyl acetate, copolymers of styrene and butadiene,
• the elastomeric capping layer may also function as a second embodiment of the barrier layer.
• suitable materials for the release layer are well known in the art, and include polyamides, polyvinyl alcohol, hydroxyalkyl cellulose, copolymers of ethylene and vinyl acetate, amphoteric interpolymers, and combinations thereof.
• the element includes an adhesive layer between the support and the support
• the photosensitive element includes at least one photopolymerizable layer that can be of a bi- or multi- layer construction. Further, the photosensitive element may include an elastomeric capping layer on the at least one
• composition is coated onto a polymeric film, such as polyester film, to form the digital layer on the film; and the digital layer on the film is applied by lamination to the surface of the photopolymenzable layer having the printed microcell pattern layer.
• a polymeric film such as polyester film
• the method for making the printing form comprises the steps of providing the photopolymerizable printing precursor having a cell pattern layer disposed between the digital layer and the photopolymerizable layer as described above; imagewise exposing the digital layer of the precursor to infrared laser radiation to selectively ablate or remove the digital layer and form an in-situ mask having open areas in which one or more features, (typically a plurality of features) of the cell pattern layer are uncovered; imagewise exposing the precursor to actinic radiation through the in-situ mask to create exposed portions (i.e., polymerized portions) and unexposed portions (i.e., unpolymerized portions) of the photopolymerizable layer; and treating the exposed precursor to remove the unexposed portions to form a relief surface suitable for printing.
• the photosensitive element is encased or substantially encased within the closed exposure chamber, such that the closed exposure chamber has an internal environment that is different during exposure from an environment external to the closed exposure chamber.
• the internal environment in the closed exposure chamber is a particular environment of a gas or gases, i.e., inert gas, and a concentration of oxygen between 190,000 ppm and 100 ppm.
• the closed exposure chamber encloses the photosensitive element in the internal environment during exposure so as to control or maintain the oxygen concentration in the exposure chamber.
• the closed exposure chamber can be a separate enclosure appended within or mounted to an existing exposure apparatus, or can be incorporated into the frame of an exposure apparatus, or can be formed from an existing structure integrated in an exposure apparatus, such as a housing.
• each cell pattern unit includes black blocks which represent areas of the digital layer (of the 45DPR precursor) that will be removed or ablated by infrared laser radiation; and, clear or white blocks which represent areas of the digital layer that will remain on the precursor.
• Each cell pattern unit has a percent mask transparency value which is obtained by dividing the total number of black blocks by the total number of blocks in the pattern. The mask transparency value is one easy way of distinguishing patterns, but it is not all inclusive.
• a relief printing plate was prepared for printing each of the five cell patterns as follows.
• the coversheet was removed from the 45DPR precursor.
• the precursor was mounted on a drum of an Esko CDI Advance 5080 digital imager unit (from Esko-Graphics, a Danaher company (Gent, Belgium)), that was equipped with Optics 40, High Resolution Optics and Pixel+ imager at 4000 pixels per inch, and an in-situ mask was formed on the precursor by laser ablating the infrared ablatable layer by repeating one of the particular cell pattern units as described in FIG. 3a through FIG. 3e.
• the CDI digital imager used laser energy of 3.8 Joules/cm 2 , and Pixel+ amplitude of 210.
• the precursor was placed in a CYREL® 3000 ETL-D exposure unit and exposed to ultraviolet radiation at 365 nm at about 16 milliWatts/cm 2 in a chamber having nitrogen gas environment for imagewise exposure through the in-situ mask for a time that was sufficient to imagewise cure the
• FIG. 4a through FIG. 4e Reproduced microscopic images of each of the five different cell patterns after printing on a laser ablatable layer are shown in FIG. 4a through FIG. 4e.
• the printed patterns shown in FIG. 4a, FIG. 4b, and FIG. 4c were all faithfully reproduced on the laser imaging layer.
• the printed pattern shown in FIG. 4d and FIG. 4e was not well reproduced since the ink tended to run together resulting in the patterns shown.
• Test Coversheet by the lamination process described.
• Each of the Test Coversheets having the infrared-sensitive ablation layer on a support, and a particular cell pattern printed with an ink that is UV-opaque and IR-transparent on the infrared- sensitive ablation layer was laminated to a Lamination Plate using the method described above.
• the final structure of the Test Printing Plate Precursor was, in order, a polyester film support, a photopolymerizable layer, a layer of printed cell pattern, an infrared-sensitive laser ablatable layer used to form mask, and a removable polyester film support as a protective coversheet.
• the photopolymerizable layer Exposure in the controlled environment of nitrogen gas and oxygen concentration of 3% was sufficient to form desired shape of the raised elements, such as flat-topped highlight dots, and form the microcell pattern on the print surface of the relief printing plate without the extra time and control required to assure complete inert gas environment of nitrogen. Similar to the preparation of the 45DPR printing plates to print the cell pattern, the Plate Precursor was then exposed to ultraviolet radiation through the support, washout developed in solvent solution, dried, post-exposed and light finished as described above, but in accordance with the standard practices for a DSR plate, to produce Test Relief Printing Plate having a relief surface.
• Test Relief Printing Plates were used to print the solids onto a substrate.
• Each Test Relief Printing Plate was mounted onto a PCMC Avanti Central Impression flexographic printing press, and Sun Process GS Cyan CRVFS5134539/K525 solvent-based printing ink was used to print onto a Bemis 20" wide, 1 .5 mil Film (White LLDPE Mono (MA1 1 -A104-EO) as the substrate.
• a new cell pattern was created on the infrared-sensitive laser ablatable layer by sequential printing of two different repeating cell pattern units, instead of the steps as described in Example 1 of designing and storing as an image file in a digital imager unit a cell pattern unit as shown in FIG. 3g that would be used in forming a digital mask on the precursor.
• the sequential printing of two different repeating cell pattern units should have created or substantially created as the cell pattern unit that is shown in FIG. 3g.
• the Digital Coversheet of Test 6 was printed on an infrared-sensitive laser ablatable layer was the combination of the repeating cell pattern unit as shown in FIG. 3b and the repeating cell pattern unit as shown in FIG. 3c.
• This Digital Coversheet of Test 6 was prepared by first printing with ink by the printing plate that was made with the repetition of cell pattern unit of FIG. 3b onto the laser ablatable layer of the infrared-sensitive element web; and, then printing with ink by the printing plate that was made with the repetition of cell pattern unit of FIG. 3c onto the previously printed cell pattern layer.
• mis-registration of the two different cell patterns and web stretch resulted in a semi-random pattern as shown in the reproduction of the microscopic image taken of the Digital
• Example 2 demonstrated that significant increases in solid ink density can be made by printing with a particular ink an image on a laser ablatable layer, which is then incorporated into the digital printing form precursor, and utilized in the method to prepare a relief printing form for flexographic printing from the precursor.
• the printed image should be transparent to near infrared radiation that is used by the digital imager in the ablation process that forms the in-situ mask so as not to be removed by ablation; and, should be sufficiently opaque to ultraviolet radiation in order to produce the fine microcell structures on the printing surface of the relief printing form that result in increased solid ink density upon printing.
• a new cell pattern unit was designed as shown in FIG. 3i, and used by the digital imager unit to form an in-situ mask for the 45DPR precursor, which was prepared into a printing plate and used to print the cell pattern onto a surface of an infrared-sensitive laser ablatable layer and form a Digital Coversheet of Test 2 for Example 3.
• the CDI digital imager used laser energy of 3.2 Joules/cm 2 , and Pixel+ amplitude of 120.

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• Physics & Mathematics (AREA)
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• General Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Optics & Photonics (AREA)
• Manufacturing & Machinery (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
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• Materials Engineering (AREA)
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• Printing Plates And Materials Therefor (AREA)

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• 2016
  • 2016-05-26 US US15/165,469 patent/US10668711B2/en active Active
  • 2016-05-27 KR KR1020177037359A patent/KR102616599B1/ko active Active
  • 2016-05-27 WO PCT/US2016/034563 patent/WO2016196257A2/en not_active Ceased
  • 2016-05-27 EP EP16728514.7A patent/EP3304206B1/en active Active
  • 2016-05-27 CN CN201680043541.XA patent/CN107850857B/zh active Active
  • 2016-05-27 JP JP2017563021A patent/JP6901410B2/ja active Active
• 2020
  • 2020-04-24 US US16/858,474 patent/US11465402B2/en active Active
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  • 2022-09-07 US US17/939,588 patent/US11858252B2/en active Active

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