Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
  • B41N3/00—Preparing for use and conserving printing surfaces
  • B41N3/03—Chemical or electrical pretreatment
  • B41N3/036—Chemical or electrical pretreatment characterised by the presence of a polymeric hydrophilic coating
• • 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
  • G03F7/16—Coating processes; Apparatus therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C1/00—Forme preparation
  • B41C1/10—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme
  • B41C1/1008—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme by removal or destruction of lithographic material on the lithographic support, e.g. by laser or spark ablation; by the use of materials rendered soluble or insoluble by heat exposure, e.g. by heat produced from a light to heat transforming system; by on-the-press exposure or on-the-press development, e.g. by the fountain of photolithographic materials
  • B41C1/1016—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme by removal or destruction of lithographic material on the lithographic support, e.g. by laser or spark ablation; by the use of materials rendered soluble or insoluble by heat exposure, e.g. by heat produced from a light to heat transforming system; by on-the-press exposure or on-the-press development, e.g. by the fountain of photolithographic materials characterised by structural details, e.g. protective layers, backcoat layers or several imaging layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C2201/00—Location, type or constituents of the non-imaging layers in lithographic printing formes
  • B41C2201/02—Cover layers; Protective layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C2201/00—Location, type or constituents of the non-imaging layers in lithographic printing formes
  • B41C2201/14—Location, type or constituents of the non-imaging layers in lithographic printing formes characterised by macromolecular organic compounds, e.g. binder, adhesives
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C2210/00—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation
  • B41C2210/04—Negative working, i.e. the non-exposed (non-imaged) areas are removed
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C2210/00—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation
  • B41C2210/08—Developable by water or the fountain solution
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C2210/00—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation
  • B41C2210/22—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation characterised by organic non-macromolecular additives, e.g. dyes, UV-absorbers, plasticisers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C2210/00—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation
  • B41C2210/24—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation characterised by a macromolecular compound or binder obtained by reactions involving carbon-to-carbon unsaturated bonds, e.g. acrylics, vinyl polymers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
  • Y10T428/24479—Structurally defined web or sheet [e.g., overall dimension, etc.] including variation in thickness
  • Y10T428/24612—Composite web or sheet
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/27—Web or sheet containing structurally defined element or component, the element or component having a specified weight per unit area [e.g., gms/sq cm, lbs/sq ft, etc.]
  • Y10T428/273—Web or sheet containing structurally defined element or component, the element or component having a specified weight per unit area [e.g., gms/sq cm, lbs/sq ft, etc.] of coating
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31551—Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
  • Y10T428/31609—Particulate metal or metal compound-containing
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31725—Of polyamide

Definitions

• This invention relates to hydrophilic substrates having a unique interlayer and to imageable elements such as negative-working lithographic printing plate precursors having the noted hydrophilic substrate.
• the invention also relates to methods of using these imageable elements.
• Radiation-sensitive compositions are routinely used in the preparation of imageable materials including lithographic printing plate precursors.
• Such compositions generally include a radiation-sensitive component, an initiator system, and a binder, each of which has been the focus of research to provide various improvements in physical properties, imaging performance, and image characteristics.
• Recent developments in the field of printing plate precursors concern the use of radiation-sensitive compositions that can be imaged by means of lasers or laser diodes, and more particularly, that can be imaged and/or developed on-press.
• Laser exposure does not require conventional silver halide graphic arts films as intermediate information carriers (or "masks") since the lasers can be controlled directly by computers.
• High-performance lasers or laser- diodes that are used in commercially-available image-setters generally emit radiation having a wavelength of at least 700 run, and thus the radiation-sensitive compositions are required to be sensitive in the near-infrared or infrared region of the electromagnetic spectrum.
• other useful radiation-sensitive compositions are designed for imaging with ultraviolet or visible radiation.
• Patent Application Publications 2003/0118939 West et al.
• 2005/0008971 Mitsubishi et al.
• 2005/0204943 Mikino et al.
• EP l,079,276A Lifka et al.
• EP 1,182,033 A Fejimaki et al.
• EP 1,449,65OA Goto.
• lithography has generally been carried out using a polymeric or metal substrate (or "support”) such as a substrate comprising an aluminum or aluminum alloy support of various metallic compositions.
• the surface of the metal sheet is generally roughened by surface graining in order to ensure good adhesion to a layer, usually an imageable layer, that is disposed thereon and to improve water retention in non-imaged regions during printing.
• a layer usually an imageable layer
• Various aluminum support materials and methods of preparing them are described in U.S. Patents 5,076,899 (Sakaki et al.) and 5,518,589 (Matsura et al.).
• a continuous web of raw aluminum can be treated, for example, using a sequence of known steps.
• steps may include taking the continuous aluminum web through a degreasing section of a manufacturing machine to remove oils and debris from the aluminum web, an alkali etching section , first rinsing section, graining section (that can include mechanical or electrochemical graining, or both), second rinsing section, post-graining acidic- or alkali-etching section, third rinsing section, anodization section using a suitable acid to provide an anodic oxide coating, fourth rinsing section, post-treatment section, final or fifth rinsing section, and drying section, before either being rewound or passed on to coating stations for application of imageable layer formulations.
• the aluminum web is treated to form an aluminum oxide layer on its surface so it will exhibit a high degree of mechanical abrasion resistance necessary during the printing process.
• This oxide layer is already hydrophilic to some degree, which is significant for having a high affinity for water and for repelling printing ink.
• the oxide layer is so reactive that it can interact with components of the imageable layer in the imageable element.
• the oxide layer may partially or completely cover the aluminum substrate surface.
• the oxide layer is covered with a hydrophilic protective layer (also known in the art as a "seal”, “sublayer”, or “interlayer”) to increase its hydrophilicity before one or more imageable layer formulations are applied.
• a hydrophilic protective layer can be applied by immersing the web in the post-treatment solution or by spraying the solution onto the web (with optional recovery tank, filter, and fluid delivery system).
• a suitable interlayer may also ensure that during development, the soluble regions of the imageable layer are easily removed from the substrate, leaving no residue and providing clean hydrophilic backgrounds.
• the hydrophilic interlayer can also protect the aluminum oxide layer against corrosion during development with highly alkaline developers and from dye penetration from the imageable layer.
• hydrophilic interlayers are prepared from formulations including poly( vinyl phosphonic acid) (PVPA), vinyl phosphonic acid/acrylic acid (VP A/ AA) copolymers, and poly(acrylic acid) (PAA) as described for example in U.S. Patent 4,153,461 (Berghauser et al.) and EP 0 537 633Bl (Elsaesser et al.).
• PVPA poly( vinyl phosphonic acid)
• VP A/ AA vinyl phosphonic acid/acrylic acid
• PAA poly(acrylic acid)
• U.S. Patent 4,427,765 (Mohr et al.) describes the use of a water- soluble organic polymer having acidic functional groups (such as phosphorous or sulfonic acid groups) with a salt of a divalent metal cation.
• acidic functional groups such as phosphorous or sulfonic acid groups
• Various organic polymers and metal cations are described that are believed to form a complex of polymer and metal cation.
• U.S. Patent 5,314,787 (Elsaesser et al.) describes the treatment of aluminum substrates with a hydrophilic polymer solution followed by treatment with a solution containing divalent or polyvalent metal cations.
• U.S. Patent 7,214,468 (Takahashi et al.) describes the use of flexible supports having a hydrophilic layer comprised of metal oxide sols. Reactive functional groups have also been added to aluminum and polymer supports as described in U.S. Patent 5,807,659 (Nishimiya et al.) and EP Publication 1,495,866 Al (Mitsumoto et al.). An intermediate layer comprising a polymer derived from a phosphate-substituted methacrylate is described in EP Publication 1 ,788,429 (Loccufier et al.).
• a hydrophilic layer on the metal support of lithographic elements described in EP Publication 1,791,699 contains a phosphono- substituted siloxane.
• EP Publication 1,787,166 (Strehmel et al.) describes the use of phosphate-containing compounds in interlayers.
• U.S. Patent 7,049,048 (Hunter et al.) describes an interlayer material on an aluminum support in lithographic elements that includes a copolymer having acidic groups and silyl groups that are substituted with three alkoxy or phenoxy groups.
• hydrophilic substrates having hydrophilic interlayer compositions that provide desired adhesion to overlying imageable layers even under humid conditions.
• the present invention provides a substrate comprising a metal or polymer support having thereon an interlayer comprising a trialkoxysilyl polyethylene glycol acrylate having the following Structure (I): (OR 6 ) 3
• R 1 and R 2 are independently hydrogen or Ci to C 6 alkyl, Ci to C 6 alkenyl, Ci to C 6 alkoxy, Ci to C 6 acyl, Ci to C 6 acyloxy, phenyl, halo, or cyano groups, or R 1 and R 2 together can form a cyclic group,
• R 3 is hydrogen, or a Ci to C 6 alkyl, phenyl, halo, or cyano group
• R 4 and R 5 are independently hydrogen or methyl groups
• R 6 is hydrogen or a Ci to Ci 2 alkyl group
• Xi is -O- or -NR- wherein R is hydrogen or an alkyl or aryl group
• X 2 is -NR'- wherein R' is hydrogen or an alkyl or aryl group, m is an integer of from 15 to 200, and n is an integer of from 1 to 12.
• This invention also provides a negative-working imageable element comprising a substrate having disposed thereon an imageable layer that becomes more insoluble in a processing solution after exposure to imaging radiation (such as infrared imaging radiation), and the imageable element further comprises, between the substrate and the imageable layer: an interlayer comprising the trialkoxysilyl polyethylene glycol acrylate represented by Structure (I) identified above.
• the imageable elements of this invention are negative- working, on-press developable imageable elements comprising the substrate of this invention that has thereon an imageable layer comprising: a radically polymerizable component, an initiator composition capable of generating free radicals sufficient to initiate polymerization of free radically polymerizable groups upon exposure to imaging infrared radiation, a primary polymeric binder that has a backbone to which are attached pendant poly(alkylene oxide) side chains, cyano groups, or both, and is optionally present in the form of discrete particles, and an infrared radiation absorbing compound, the imageable element further comprising between the substrate and the imageable layer, an interlayer comprising a trialkoxysilyl polyethylene glycol acrylate defined by Structure (I) described herein.
• This invention also provides a method comprising: A) imagewise exposing the imageable element of this invention using infrared imaging radiation to produce exposed and non-exposed regions, and
• imageable elements of this invention are on-press developable negative- working printing plate precursors that are developed only in the presence of a fountain solution, lithographic printing ink, or a combination thereof.
• the imageable elements comprise an infrared radiation absorbing dye, a primary polymeric binder that is in the form of discrete particles having an average particle size of from 10 to 500 nm, and is present in the imageable layer in an amount of at least 10% and up to 90% based on the total imageable layer dry weight
• the initiator composition comprises an iodonium compound, or the combination of a diaryliodonium cation and a boron-containing anion, wherein the diaryliodonium cation is represented by the following Structure (IB):
• Ri, R 2 , R 3 , and R* are independently alkyl, aryl, alkenyl, alkynyl, cycloalkyl, or heterocyclyl groups, or two or more of Ri, R 2 , R 3 , and R 4 can be joined together to form a heterocyclic ring with the boron atom, such rings having up to 7 carbon, nitrogen, oxygen, or nitrogen atoms, in the interlayer, the trialkoxysilyl polyethylene glycol acrylate having
• Structure (I) has R 1 and R 2 that are independently hydrogen or a Ci to C 4 alkyl group or phenyl group, R 3 that is hydrogen or a Ci to C 3 alkyl or phenyl group, R 6 that is a Ci to C 4 alkyl group, X 1 is -O- or -NH-, X 2 that is -NH- or -NCH 3 -, m that is an integer of from 20 to 70, and n that is an integer of from 2 to 6, and a substrate that comprises a sulfuric acid-anodized aluminum- containing support upon which the interlayer is disposed.
• the method of this invention can be used to provide an on-press developed lithographic printing plate.
• the interlayer composition used in the practice of this invention provides hydrophilicity to the substrate for various uses and particularly for lithographic elements that include an imageable layer disposed thereon.
• the interlayer provides improved adhesion to overlying imageable layer(s) without adversely affecting other desired properties in the element. It is believed that the compound shown in Structure (I) provides improved developer solubility and layer stability because of the presence of the urea linkage.
• interlayer we intend a layer that is disposed on the metal or polymer support (described below) in various ways. The art may also consider this interlayer as a "sublayer” and we mean those terms to be the same thing in the practice of this invention. Moreover, unless otherwise indicated, percentages refer to percents by dry weight.
• “Graft” polymer or copolymer refers to a polymer having a side chain that has a molecular weight of at least 200.
• polymer refers to high and low molecular weight polymers including oligomers and includes homopolymers and copolymers.
• copolymer refers to polymers that are derived from two or more different monomers.
• backbone refers to the chain of atoms (carbon or heteroatoms) in a polymer to which a plurality of pendant groups are attached.
• a backbone is an "all carbon" backbone obtained from the polymerization of one or more ethyl enically unsaturated polymerizable monomers.
• other backbones can include heteroatoms wherein the polymer is formed by a condensation reaction or some other means.
• the interlayer composition used in the practice of this invention comprises a trialkoxysilyl polyethylene glycol acrylate having the following Structure (I):
• R 1 and R 2 are independently hydrogen or Ci to C 6 alkyl (substituted or unsubstituted, linear or branched), Cj to C 6 alkenyl (substituted or unsubstituted, linear or branched), Ci to C 6 alkoxy (substituted or unsubstituted, linear or branched), Ci to C 6 acyl (substituted or unsubstituted, linear or branched), Ci to C 6 acyloxy (substituted or unsubstituted, linear or branched), substituted or unsubstituted phenyl, halo, or cyano groups, or R 1 and R 2 together can form a substituted or unsubstituted cyclic group, for example having 3 to 7 atoms in the ring.
• R 1 and R 2 are independently hydrogen or a Ci to C 4 alkyl group (substituted or unsubstituted) or a substituted or unsubstituted phenyl group. More specifically, R 1 and R 2 can be independently hydrogen or substituted or unsubstituted methyl groups.
• R 3 is hydrogen, or a Ci to C 6 alkyl (substituted or unsubstituted, linear or branched), substituted or unsubstituted phenyl, halo, or cyano group.
• R 3 can be hydrogen or a Ci to C 3 alkyl (substituted or unsubstituted) or a substituted or unsubstituted phenyl group. More typically, R 3 is hydrogen or a substituted or unsubstituted methyl group.
• R 4 and R 5 are independently hydrogen or substituted or unsubstituted methyl groups.
• R 6 is hydrogen or a Ci to C 12 alkyl group (substituted or unsubstituted, linear or branched, including benzyl groups).
• R 6 is a Ci to C 4 alkyl group (substituted or unsubstituted), such as a substituted or unsubstituted methyl or ethyl group.
• Xi is -O- or -NR- wherein R is hydrogen or a substituted or unsubstituted alkyl having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 or 10 carbon atoms in the ring.
• R is hydrogen or a substituted or unsubstituted alkyl having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 or 10 carbon atoms in the ring.
• Xi can be -O- or -NH-, or more typically, -NH-.
• X 2 is -NR'- wherein R' is hydrogen or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 or 10 carbon atoms in the ring.
• R' is hydrogen or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 or 10 carbon atoms in the ring.
• X 2 can be -NH- or -NCH 3 -, or more typically, -NH-.
• m is an integer of from 15 to 200 or typically from 20 to 70 or from 25 to 60
• n is an integer of from 1 to 12 or from 2 to 6, or from 2 to 4.
• the interlayer composition comprises a reaction product of Jeffamine (meth)acrylamide with 3-isocyanatopropyl triethoxysilane.
• Other useful interlayer compositions include surfactants such as that present in the commercial product Masurf ® 1520 that can be obtained from Mason Chemical Company.
• the dry interlayer coverage on the metal or polymeric support is generally at least 0.0001 and up to 0.1 g/m 2 and typically from 0.007 to 0.07 g/m 2 .
• the coverage may be lower if the interlayer formulation is applied to the support by a dip and rinse process and it may be higher if the interlayer formulation is applied to the support by using a slot coater (for example from 0.03 to 0.06 g/m 2 ).
• the substrate has a hydrophilic surface, or at least a surface that is more hydrophilic than the applied imageable layer compositions on the imaging side.
• the substrate comprises a support that can be composed of any polymeric or metal support material that is conventionally used to prepare imageable elements such as lithographic printing plates.
• the support can be any self-supporting material including polymeric films (such as polyester, polyethylene, polycarbonate, cellulose ester polymer, and polystyrene films), glass, ceramics, metal sheets or foils, or stiff papers (including resin-coated and metallized papers), or a lamination of any of these materials (such as a lamination of an aluminum foil onto a polyester film).
• Metal supports include sheets or foils of aluminum, copper, zinc, titanium, and alloys thereof.
• Both polymeric film and metal supports are modified on one or both flat surfaces with the interlayer composition described above.
• One useful substrate is composed of an aluminum-containing support that may be treated using techniques known in the art, including roughening of some type by physical (mechanical) graining, electrochemical graining, or chemical graining, usually followed by acid anodizing.
• the aluminum support can be roughened by physical or electrochemical graining and then anodized using phosphoric or sulfuric acid and conventional procedures.
• a useful substrate is an electrochemically grained and sulfuric acid anodized aluminum support that has been treated or coated with the interlayer composition described above.
• Sulfuric acid anodization of the aluminum support generally provides an oxide weight (coverage) on the surface of from 1.5 to 5 g/m 2 and more typically from 3 to 4.3 g/m 2 .
• Phosphoric acid anodization generally provides an oxide weight on the surface of from 1.5 to 5 g/m 2 and more typically from 1 to 3 g/m 2 .
• the surface of the aluminum-containing support can be electrochemically grained using the procedure and chemistry described in U.S. Patent Publication No. 2008/0003411 (Hunter et al.) that is also cited herein.
• the roughened aluminum-containing support is subjected to alternating current preferably in an electrolytic solution containing a suitable strong acid such as hydrochloric, nitric acid, or mixtures thereof.
• the acidic concentration of the electrolytic solution is generally from 0.4% and typically from 0.7% to 2% for hydrochloric acid, or from 0.2% and typically from 0.4% to 2.5% for nitric acid.
• Optional additives can be present in the electrolytic solution as corrosion inhibitors or stabilizers including but not limited to, metal nitrates and chlorides (such as aluminum nitrate and aluminum chloride), monoamines, diamines, aldehydes, phosphoric acid, chromic acid, boric acid, lactic acid, acetic acid, and oxalic acid.
• metal nitrates and chlorides such as aluminum nitrate and aluminum chloride
• the thickness of the substrate can be varied but should be sufficient to sustain the wear from printing and thin enough to wrap around a printing form.
• Useful embodiments include a treated aluminum foil having a thickness of at least 100 ⁇ m and up to and including 700 ⁇ m.
• the supports used to prepare as substrates have the desired tensile strength, elasticity, crystallinity, conductivity, and other physical properties that are conventional in the lithographic art, which properties can be achieved using known treatments such as heat treatment, cold or hot fabrication processes, or other methods conventional in the art of aluminum alloy fabrication for lithographic substrate preparation.
• the substrates can be prepared as continuous webs or coiled strips to provide substrates as continuous webs that can be cut into desired sheets at a later time.
• the backside (non-imaging side) of the substrate may be coated with antistatic agents and/or slipping layers or a matte layer to improve handling and "feel" of the imageable element.
• the substrate can also be a cylindrical surface having the radiation- sensitive composition applied thereon, and thus be an integral part of the printing press. The use of such imaging cylinders is described for example in U.S. Patent 5,713,287 (Gelbart).
• the interlayer composition can be applied to the substrate as a solution or dispersion in a coating liquid using any suitable equipment and procedure.
• the interlayer can be formed by dipping the support into a 0.01-10% (weight) warm to hot (30 to 9O 0 C) aqueous solution of the interlayer composition for 10 to 30 seconds.
• the interlayer composition can be applied by conventional methods such as spin coating, knife coating, gravure coating, die coating, slot coating, bar coating, wire rod coating, roller coating, dipping, or extrusion hopper coating.
• the composition can also be applied by spraying onto a suitable support (such as an on-press printing cylinder).
• Useful solvents for dissolving the compounds of Structure (I) to form an interlayer composition include water, alcohols, ketones, and water/alcohol mixtures.
• the resulting solutions can also include fluorosurfactants.
• Specific interlayer formulations and a method of application are described in the Examples below, but one skilled in the art would readily know how to adapt known processes to apply the interlayer formulations in manufacturing.
• Imageable Elements can be used in photomask lithography, chemically amplified resists, imprint lithography, microelectronic and microoptical devices, printed circuit boards, and particularly lithographic printing plate precursors.
• the present invention is directed to negative-working imageable elements in which a single infrared radiation-sensitive imageable layer is disposed on and adhered to the substrate of this invention.
• the exposed regions become less soluble in developing or processing solutions while the non-exposed regions are removable in those solutions.
• the IR radiation-sensitive composition includes one or more free radically polymerizable components, each of which contains one or more free radically polymerizable groups that can be polymerized using free radical initiation.
• free radically polymerizable components can contain one or more free radical polymerizable monomers or oligomers having one or more addition polymerizable ethylenically unsaturated groups, crosslinkable ethylenically unsaturated groups, ring-opening polymerizable groups, azido groups, aryldiazonium salt groups, aryldiazosulfonate groups, or a combination thereof.
• crosslinkable polymers having such free radically polymerizable groups can also be used.
• Suitable ethylenically unsaturated components that can be polymerized or crosslinked include ethylenically unsaturated polymerizable monomers that have one or more of the polymerizable groups, including unsaturated esters of alcohols, such as acrylate and methacrylate esters of polyols. Oligomers or prepolymers, such as urethane acrylates and methacrylates, epoxide acrylates and methacrylates, polyester acrylates and methacrylates, polyether acrylates and methacrylates, and unsaturated polyester resins can also be used.
• the free radically polymerizable component comprises carboxy groups.
• Useful free radically polymerizable components include free- radical polymerizable monomers or oligomers that comprise addition polymerizable ethylenically unsaturated groups including multiple acrylate and methacrylate groups and combinations thereof, or free-radical crosslinkable polymers.
• Free radically polymerizable compounds include those derived from urea urethane (meth)acrylates or urethane (meth)acrylates having multiple polymerizable groups.
• a free radically polymerizable component can be prepared by reacting DESMODUR ® NlOO aliphatic polyisocyanate resin based on hexamethylene diisocyanate (Bayer Corp., Milford, Conn.) with hydroxyethyl acrylate and pentaerythritol triacrylate.
• Useful free radically polymerizable compounds include NK Ester A-DPH (dipentaerythritol hexaacrylate) that is available from Kowa American, and Sartomer 399 (dipentaerythritol pentaacrylate), Sartomer 355 (di-trimethylolpropane tetraacrylate), Sartomer 295 (pentaerythritol tetraacrylate), and Sartomer 415
• the IR radiation-sensitive composition may include polymeric materials that include side chains attached to the backbone, which side chains include one or more free radically polymerizable groups (such as ethylenically unsaturated groups) that can be polymerized (crosslinked) in response to free radicals produced by the initiator composition (described below). There may be at least two of these side chains per molecule.
• the free radically polymerizable groups (or ethylenically unsaturated groups) can be part of aliphatic or aromatic acrylate side chains attached to the polymeric backbone. Generally, there are at least 2 and up to 20 such groups per molecule, or typically from 2 to 10 such groups per molecule.
• Such free radically polymerizable polymers can also comprise hydrophilic groups including but not limited to, carboxy, sulfo, or phospho groups, either attached directly to the backbone or attached as part of side chains other than the free radically polymerizable side chains.
• Useful commercial products that comprise polymers that can be used in this manner include Bayhydrol ® UV VP LS 2280, Bayhydrol ® UV VP LS 2282, Bayhydrol ® UV VP LS 2317, Bayhydrol ® UV VP LS 2348, and Bayhydrol ® UV XP 2420, that are all available from Bayer MaterialScience, as well as LaromerTM LR 8949, LaromerTM LR 8983, and LaromerTM LR 9005, that are all available from BASF.
• the one or more free radically polymerizable components can be present in the imageable layer in an amount of at least 10 weight % and up to 80 weight %, and typically from 20 to 50 weight %, based on the total dry weight of the imageable layer.
• the weight ratio of the free radically polymerizable component to the total polymeric binders is generally from 5:95 to 95:5, and typically from 10:90 to 90:10, or even from 30:70 to 70:30.
• the IR radiation-sensitive composition also includes an initiator composition that includes one or more initiators that are capable of generating free radicals sufficient to initiate polymerization of all the various free radically polymerizable components upon exposure of the composition to imaging radiation.
• the initiator composition is generally responsive to infrared imaging radiation corresponding to the spectral range of at least 700 nm and up to and including 1400 nm (typically from 750 to 1250 nm). Initiator compositions are used that are appropriate for the desired imaging wavelength(s).
• the initiator composition can include one or more iodonium cations and one or more boron-containing anions at a molar ratio of at least 1.2:1 and up to 3.0: 1 , and typically from 1.4: 1 to 2.5: 1 or from 1.4: 1 to 2.0: 1.
• iodonium cations are well known in the art including but not limited to, U.S. Patent Application Publication 2002/0068241 (Oohashi et al.), WO 2004/101280 (Munnelly et al.), and U.S. Patents 5,086,086 (Brown-Wensley et al.), 5,965,319 (Kobayashi), and 6,051,366 (Baumann et al.).
• a useful iodonium cation includes a positively charged iodonium, (4- methylphenyl)[4-(2-methylpropyl)phenyl]- moiety and a suitable negatively charged counterion.
• iodonium salt is available as Irgacure ® 250 from Ciba Specialty Chemicals (Tarrytown, NY) that is (4-methylphenyl)[4-(2-methylpropyl)phenyl]iodonium hexafluorophosphate and is supplied in a 75% propylene carbonate solution.
• the iodonium cations can be paired with a suitable number of negatively-charged counterions such as halides, hexafluorophosphate, thiosulfate, hexafluoroantimonate, tetrafluoroborate, sulfonates, hydroxide, perchlorate, others readily apparent to one skilled in the art.
• the iodonium cations can be supplied as part of one or more iodonium salts, and as described below, the iodonium cations can be supplied as iodonium borates also containing suitable boron-containing anions.
• the iodonium cations and the boron-containing anions can be supplied as part of salts that are combinations of Structures (IB) and (IBz) described below, or both the iodonium cations and boron-containing anions can be supplied from different sources.
• the iodonium borate salts since such salts generally supply a 1 : 1 molar ratio of iodonium cations to boron- containing anions, additional iodonium cations must be supplied from other sources, for example, from iodonium salts described above.
• the imageable layer (and element) can comprise a mixture of iodonium cations, some of which are derived from an iodonium borate (described below) and others of which are derived from a non-boron-containing iodonium salt (described above).
• the molar ratio of iodonium derived from the iodonium borate to the iodonium derived from the non-boron-containing iodonium salt can be up to 5:1 and typically up to 2.5: 1.
• diaryliodonium cations that are represented by the following Structure (IB):
• X and Y are independently halo groups (for example, fluoro, chloro, or bromo), substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms (for example, methyl, chloromethyl, ethyl, 2-methoxyethyl, n-propyl, isopropyl, is ⁇ butyl, n-butyl, t-butyl, all branched and linear pentyl groups, 1-ethylpentyl, 4- methylpentyl, all hexyl isomers, all octyl isomers, benzyl, 4-methoxybenzyl,/?- methylbenzyl, all dodecyl isomers, all icosyl isomers, and substituted or unsubstituted mono-and poly-, branched and linear haloalkyls), substituted or unsubstituted alkyloxy having 1 to 20 carbon atoms
• X and Y are independently substituted or unsubstituted alkyl groups having 1 to 8 carbon atoms, alkyloxy groups having 1 to 8 carbon atoms, or cycloalkyl groups having 5 or 6 carbon atoms in the ring, and more preferably, X and Y are independently substituted or unsubstituted alkyl groups having 3 to 6 carbon atoms (and particularly branched alkyl groups having 3 to 6 carbon atoms).
• X and Y can be the same or different groups
• the various X groups can be the same or different groups
• the various Y groups can be the same or different groups.
• symmetric compounds are preferred (that is, they have the same groups on both phenyl rings).
• two or more adjacent X or Y groups can be combined to form a fused carbocyclic or heterocyclic ring with the respective phenyl groups.
• the X and Y groups can be in any position on the phenyl rings but typically they are at the 2- or 4-positions on either or both phenyl rings.
• the sum of the carbon atoms in the X and Y substituents generally is at least 6, and typically at least 8, and up to 40 carbon atoms.
• one or more X groups can comprise at least 6 carbon atoms, and Y does not exist (q is 0).
• one or more Y groups can comprise at least 6 carbon atoms, and X does not exist (p is 0).
• one or more X groups can comprise less than 6 carbon atoms and one or more Y groups can comprise less than 6 carbon atoms as long as the sum of the carbon atoms in both X and Y is at least 6.
• p and q are independently 0 or integers of 1 to 5, provided that either p or q is at least 1. Typically, both p and q are at least 1, or each of p and q is 1.
• the carbon atoms in the phenyl rings that are not substituted by X or Y groups have a hydrogen atom at those ring positions.
• Useful boron-containing anions are organic anions having four organic groups attached to the boron atom. Such organic anions can be aliphatic, aromatic, heterocyclic, or a combination of any of these. Generally, the organic groups are substituted or unsubstituted aliphatic or carbocyclic aromatic groups.
• useful boron-containing anions can be represented by the following Structure (IB Z ):
• R 1 , R 2 , R 3 , and R 4 are independently substituted or unsubstituted alkyl groups having 1 to 12 carbon atoms (such as methyl, ethyl, n-propyl, isopropyl, n- butyl, isobutyl, t-butyl, all pentyl isomers, 2-methylpentyl, all hexyl isomers, 2- ethylhexyl, all octyl isomers, 2,4,4-trimethylpentyl, all nonyl isomers, all decyl isomers, all undecyl isomers, all dodecyl isomers, methoxymethyl, and benzyl) other than fluoroalkyl groups, substituted or unsubstituted carbocyclic aryl groups having 6 to 10 carbon atoms in the aromatic ring (such as phenyl, />-methylphenyl, 2,4
• two or more OfR 1 , R 2 , R 3 , and R 4 can be joined together to form a heterocyclic ring with the boron atom, such rings having up to 7 carbon, nitrogen, oxygen, or nitrogen atoms. None of the R 1 through R 4 groups contains halogen atoms and particularly fluorine atoms.
• R 1 , R 2 , R 3 , and R 4 are independently substituted or unsubstituted alkyl or aryl groups as defined above, and more typically, at least 3 of Ri, R 2 , R 3 , and R 4 are the same or different substituted or unsubstituted aryl groups (such as substituted or unsubstituted phenyl groups).
• all of R 1 , R 2 , R 3 , and R 4 can be the same or different substituted or unsubstituted aryl groups, or all of the groups are the same substituted or unsubstituted phenyl group.
• Z " can be a tetraphenyl borate wherein the phenyl groups are substituted or unsubstituted (for example, all are unsubstituted phenyl groups).
• Some representative iodonium borate compounds include but are not limited to, 4-octyloxyphenyl phenyliodonium tetraphenylborate, [4-[(2- hydroxytetradecyl)-oxy]phenyl]phenyliodonium tetraphenylborate, bis(4-t- butylphenyl)iodonium tetraphenylborate, 4-methylphenyl-4'- hexylphenyliodonium tetraphenylborate, 4-methylphenyl-4'- cyclohexylphenyliodonium tetraphenylborate, bis(t-butylphenyl)iodonium tetrakis(pentafluorophenyl)borate, 4-hexylphenyl-phenyliodonium tetraphenylborate, 4-methylphenyl-4'-cyclohexylphenyliodon
• diaryliodonium borate compounds can be prepared, in general, by reacting an aryl iodide with a substituted or unsubstituted arene, followed by an ion exchange with a borate anion. Details of various preparatory methods are described in U.S. Patent 6,306,555 (Schulz et al.), and references cited therein, and by Crivello, J.Polymer ScL, Part A: Polymer Chemistry, 37, 4241-4254 (1999).
• the boron-containing anions can also be supplied as part of infrared radiation absorbing dyes (for example, cationic dyes) as described below. Such boron-containing anions generally are defined as described above with Structure (IBz).
• the iodonium cations and boron-containing anions are generally present in the imageable layer in a combined amount of at least 1 % and up to and including 15%, and typically at least 4 and up to and including 10%, based on total dry weight of the imageable layer.
• the optimum amount of the various initiator components may differ for various compounds and the sensitivity of the radiation-sensitive composition that is desired and would be readily apparent to one skilled in the art.
• the imageable layer may also include heterocyclic mercapto compounds including mercaptotriazoles, mercaptobenzimidazoles, mercaptobenzoxazoles, mercaptobenzothiazoles, mercaptobenzoxadiazoles, mercaptotetrazoles, such as those described for example in U.S. Patent 6,884,568 (Timpe et al.) in amounts of at least 0.5 and up to and including 10 weight % based on the total solids of the radiation-sensitive composition.
• heterocyclic mercapto compounds including mercaptotriazoles, mercaptobenzimidazoles, mercaptobenzoxazoles, mercaptobenzothiazoles, mercaptobenzoxadiazoles, mercaptotetrazoles, such as those described for example in U.S. Patent 6,884,568 (Timpe et al.) in amounts of at least 0.5 and up to and including 10 weight % based on the total solids
• Useful mercaptotriazoles include 3-mercapto-l,2,4-triazole, 4-methyl-3 -mercapto- 1,2,4- triazole, 5-mercapto- 1 -phenyl- 1 ,2,4-triazole, 4-amino-3 -mercapto- 1 ,2,4,-triazole, 3-mercapto-l ,5-diphenyl-l ,2,4-triazole, and 5-(p-aminophenyl)-3-mercapto-l ,2,4- triazole.
• Some useful initiator compositions include the following combinations: iodonium cations supplied from non-boron containing iodonium salts only and boron-containing anions separately supplied from other salts including cationic infrared dyes, iodonium cations supplied from both non-boron containing iodonium salts and iodonium borates and boron-containing anions from only the iodonium borates, or iodonium cations supplied from both non-boron containing iodonium salts and iodonium borates and boron-containing anions from both iodonium borates and other sources (such as cationic IR dyes).
• the radiation-sensitive composition generally includes one or more radiation absorbing compounds such as infrared radiation absorbing compounds that absorb imaging radiation, or sensitize the composition to imaging radiation having a X m3x in the IR region of the electromagnetic spectrum noted above (for example from 700 to 1400 run).
• one or more radiation absorbing compounds such as infrared radiation absorbing compounds that absorb imaging radiation, or sensitize the composition to imaging radiation having a X m3x in the IR region of the electromagnetic spectrum noted above (for example from 700 to 1400 run).
• the infrared radiation absorbing dye can be present in the radiation-sensitive composition in an amount generally of at least 0.5% and up to and including 10% and typically at least 1 and up to and including 10%, based on total dry weight of the imageable layer.
• the particular amount needed for this purpose would be readily apparent to one skilled in the art, depending upon the specific compound used.
• the imageable layer also includes a primary polymeric binder that generally has a molecular weight of at least 2,000 and up to and including 1,000,000, at least 10,000 and up to and including 200,000, or at least 10,000 and up to and including 100,000.
• the primary polymeric binder(s) can comprise at least 10 and up to 80 weight % (typically from 15 to 40 weight %), based on the total dry weight of the radiation-sensitive composition (or imageable layer).
• the polymeric binders may be homogenous, that is, dissolved in the coating solvent, or they may exist as discrete particles.
• Useful primary polymeric binders include but are not limited to, (meth)acrylic acid and acid ester resins [such as (meth)acrylates], polyvinyl acetals, phenolic resins, polymers derived from one or more (meth)acrylates, (meth)acrylonitriles, styrene, N-substituted cyclic imides or maleic anhydrides, including those described in EP 1,182,033 (Fujimaki et al.) and U.S.
• Patents 6,309,792 Hauck et al.
• 6,352,812 Shiazu et al.
• 6,569,603 Fluukawa et al.
• 6,893,797 Munnelly et al.
• Also useful are the vinyl carbazole polymers described in U.S. Patent 7,175,949 (Tao et al.), and the polymers having pendant vinyl groups as described in U.S. Patent 7,279,255 (Tao et al.).
• the imageable layer includes one or more primary polymeric binders that are present in the form of discrete particles having an average particle size of from 10 to 500 nm, and typically from 150 to 450 nm, and generally distributed uniformly within that layer.
• the particulate polymeric binders exist at room temperature as discrete particles, for example in an aqueous dispersion. However, the particles can also be partially coalesced or deformed, for example at temperatures used for drying coated imageable layer formulations. Even in this environment, the particulate structure is not destroyed.
• Such polymeric binders generally have a molecular weight (M n ) of at least 30,000 and typically at least 50,000 to 100,000, or from 60,000 to 80,000, as determined by refractive index.
• Some useful primary polymeric binders include polymeric emulsions or dispersions of polymers having pendant poly(alkylene oxide) side chains that can render the imageable elements as "on-press" developable.
• Such primary polymeric binders are described for example in U.S. Patents 6,582,882 (Pappas et al.) and 6,899,994 (noted above) and U.S. Patent Application Publication 2005/0123853 (Munnelly et al.). These primary polymeric binders are present in the imageable layer as discrete particles.
• Other useful primary polymeric binders have hydrophobic backbones and comprise both of the following a) and b) recurring units, or the b) recurring units alone: a) recurring units having pendant cyano groups attached directly to the hydrophobic backbone, and b) recurring units having hydrophilic pendant groups comprising poly(alkylene oxide) segments.
• These primary polymeric binders comprise poly(alkylene oxide) segments such as poly(ethylene oxide) or poly(propylene oxide) segments.
• These polymers can be graft copolymers having a main chain polymer and poly(alkylene oxide) pendant side chains or segments or block copolymers having blocks of (alkylene oxide)-containing recurring units and non(alkylene oxide)-containing recurring units. Both graft and block copolymers can additionally have pendant cyano groups attached directly to the hydrophobic backbone.
• the alkylene oxide constitutional units are generally C 1 to C 6 alkylene oxide groups, and more typically Ci to C 3 alkylene oxide groups.
• the alkylene portions can be linear or branched or substituted versions thereof.
• such recurring units can comprise pendant groups comprising cyano, cyano-substituted alkylene groups, or cyano- terminated alkylene groups.
• Recurring units can also be derived from ethylenically unsaturated polymerizable monomers such as acrylonitrile, methacrylonitrile, methyl cyanoacrylate, ethyl cyanoacrylate, or a combination thereof.
• cyano groups can be introduced into the polymer by other conventional means. Examples of such cyano-containing polymeric binders are described for example in U.S. Patent Application Publication 2005/003285 (Hayashi et al.).
• such primary polymeric binders can be formed by polymerization of a combination or mixture of suitable ethylenically unsaturated polymerizable monomers or macromers, such as: A) acrylonitrile, methacrylonitrile, or a combination thereof, B) poly(alkylene oxide) esters of acrylic acid or methacrylic acid, such as poly(ethylene glycol) methyl ether acrylate, poly(ethylene glycol) methyl ether methacrylate, or a combination thereof, and
• monomers such as acrylic acid, methacrylic acid, styrene, hydroxystyrene, acrylate esters, methacrylate esters (such as methyl methacrylate and benzyl methacrylate), acrylamide, methacrylamide, or a combination of such monomers.
• the amount of the poly(alkylene oxide) segments in such primary polymeric binders is from 0.5 to 60 weight % and typically from 2 to 50 weight %.
• the amount of (alkylene oxide) segments in the block copolymers is generally from 5 to 60 weight % and typically from 10 to 50 weight %. It is also likely that the primary polymeric binders having poly(alkylene oxide) side chains are present in the form of discrete particles.
• the primary polymeric binder is generally present in the radiation-sensitive composition in an amount of at least 10% and up to 90%, and typically from 10 to 70 %, based on the total imageable layer dry weight.
• These binders may comprise up to 100% of the dry weight of all polymeric binders (primary polymeric binders plus any secondary polymeric binders).
• Additional polymeric binders may also be used in the imageable layer in addition to the primary polymeric binders.
• Such polymeric binders can be any of those known in the art for use in negative- working radiation-sensitive compositions other than those mentioned above.
• the secondary polymeric binder(s) may be present in an amount of from 1.5 to 70 weight % and typically from 1.5 to 40%, based on the dry coated weight of the imageable layer, and it may comprise from 30 to 60 weight % of the dry weight of all polymeric binders.
• the secondary polymeric binders can also be particulate polymers that have a backbone comprising multiple (at least two) urethane moieties.
• Such polymeric binders generally have a molecular weight (M n ) of at least 2,000 and typically at least 100,000 to 500,000, or from 100,000 to 300,000, as determined by dynamic light scattering.
• M n molecular weight
• These polymeric binders generally are present in the imageable layer in particulate form, meaning that they exist at room temperature as discrete particles, for example in an aqueous dispersion. However, the particles can also be partially coalesced or deformed, for example at temperatures used for drying coated imageable layer formulations. Even in this environment, the particulate structure is not destroyed.
• the average particle size of these polymeric binders is from 10 to 300 nm and typically the average particle size is from 30 to 150 nm.
• the particulate secondary polymeric binder is generally obtained commercially and used as an aqueous dispersion having at least 20% and up to 50% solids. It is possible that these polymeric binders are at least partially crosslinked among urethane moieties in the same or different molecules, which crosslinking could have occurred during polymer manufacture. This still leaves the free radically polymerizable groups available for reaction during imaging.
• the secondary polymeric binders may be homogenous, that is, dissolved in the coating solvent, or may exist as discrete particles.
• Such secondary polymeric binders include but are not limited to, (meth)acrylic acid and acid ester resins [such as (meth)acrylates], polyvinyl acetals, phenolic resins, polymers derived from styrene, N-substituted cyclic imides or maleic anhydrides, such as those described in EP 1,182,033Al (Fujimaki et al.) and U.S.
• Patents 6,309,792 Hauck et al.
• 6,352,812 Shiazu et al.
• 6,569,603 Fluukawa et al.
• 6,893,797 Munnelly et al.
• Also useful are the vinyl carbazole polymers described in U.S. Patent 7,175,949 (Tao et al.), and the polymers having pendant vinyl groups as described in U.S. Patent 7,279,255 (Tao et al.).
• Additional useful secondary polymeric binders are particulate poly(urethane-acrylic) hybrids that are distributed (usually uniformly) throughout the imageable layer. Each of these hybrids has a molecular weight of from 50,000 to 500,000 and the particles have an average particle size of from 10 to 10,000 nm (preferably from 30 to 500 nm and more preferably from 30 to 150 nm). These hybrids can be either "aromatic” or “aliphatic” in nature depending upon the specific reactants used in their manufacture. Blends of particles of two or more poly(urethane-acrylic) hybrids can also be used. Some poly(urethane-acrylic) hybrids are commercially available in dispersions from Air Products and Chemicals, Inc.
• Hybridur ® 540, 560, 570, 580, 870, 878, 880 polymer dispersions of poly(urethane-acrylic) hybrid particles generally include at least 30% solids of the poly(urethane- acrylic) hybrid particles in a suitable aqueous medium that may also include commercial surfactants, anti-foaming agents, dispersing agents, anti-corrosive agents, and optionally pigments and water-miscible organic solvents.
• the imageable layer can also include a spirolactone or spirolactam colorant precursor.
• a spirolactone or spirolactam colorant precursor Such compounds are generally colorless or weakly colored until the presence of an acid causes the ring to open providing a colored species, or more intensely colored species.
• useful spirolactone and spirolactam colorant precursors include compounds represented by the following Structure (CF):
• CF wherein X is -O- or -NH-, R 5 and R 6 together form a carbocyclic or heterocyclic fused ring.
• the carbocyclic fused ring can be saturated or unsaturated and is typically 5 to 10 carbon atoms in size. Typically, 6-membered benzene fused rings are present. These rings can be substituted or unsubstituted.
• R and R are independently substituted or unsubstituted carbocyclic groups that are either saturated (aryl groups) or unsaturated (cycloalkyl groups). Typically, they are substituted or unsubstituted aryl groups having 6 or 10 carbon atoms in the ring.
• R 7 and R 8 can also be independently 5- to 10-membered, substituted or unsubstituted heterocyclic groups (such as pyrrole and indole rings). Alternatively, R 7 and R 8 together can form a substituted or unsubstituted carbocyclic or heterocyclic ring as previously defined.
• More useful colorant precursors can be represented by the following Structure (CF-I):
• Y is a nitrogen atom or methine group and R 7 and R 8 are as described above.
• Compounds wherein Y is a methine group are particularly useful.
• Examples of useful colorant precursors include but are not limited to, Crystal Violet Lactone, Malachite Green Lactone, 3-(N,N-diethylamino)-6- chloro-7-( ⁇ -ethoxyethylamino)fluoran, 3-(N,N,N-triethylamino)-6-methyl-7- anilinofluoran, 3-(N,N-diethylamino)-7-chloro-7-o-chlorofluoran, 2-(N-phenyl-N- methylamino)-6-(N-/j-tolyl-N-ethyl)aminofluoran, 2-anilino-3-methyl-6-(N-ethyl- p-toluidino)fluoran, 3,6-dimethoxyfluoran, 3-(N,N-diethylamino)-5-methyl-7- (N,N-dibenzylamino)fluoran, 3-(N-cyclohexyl-N-methyla
• the colorant precursor described above can be present in an amount of at least 1 and up to 10 weight %, and typically from 3 to 6 weight %, based on the total dry imageable layer weight.
• the radiation-sensitive composition (imageable layer) can further comprise one or more phosphate (meth)acrylates, each of which has a molecular weight generally greater than 200 and typically at least 300 and up to and including 1000.
• phosphate (meth)acrylate we also mean to include “phosphate methacrylates” and other derivatives having substituents on the vinyl group in the acrylate moiety.
• Representative phosphate (meth)acrylates include but are not limited to, ethylene glycol methacrylate phosphate (available from Aldrich Chemical Co.), a phosphate of 2-hydroxyethyl methacrylate that is available as Kayamer PM-2 from Nippon Kayaku (Japan), a phosphate of a di(caprolactone modified 2-hydroxyethyl methacrylate) that is available as Kayamer PM-21 (Nippon Kayaku, Japan), and polyethylene glycol methacrylate phosphates that are available as Phosmer M, Phosmer MH, Phosmer PE, Phosmer PEH, Phosmer PP, and Phosmer PPH from Uni-Chemical Co., Ltd. (Japan).
• the phosphate (meth)acrylate can be present in the radiation- sensitive composition in an amount of at least 0.5 and up to and including 20% and typically at least 0.9 and up to and including 10%, based on total dry composition weight.
• the imageable layer can also include a "primary additive” that is a poly(alkylene glycol) or an ether or ester thereof that has a molecular weight of at least 200 and up to and including 4000.
• This primary additive can be present in an amount of at least 2 and up to and including 50 weight %, based on the total dry weight of the imageable layer.
• Useful primary additives include, but are not limited to, one or more of polyethylene glycol, polypropylene glycol, polyethylene glycol methyl ether, polyethylene glycol dimethyl ether, polyethylene glycol monoethyl ether, polyethylene glycol diacrylate, ethoxylated bisphenol A di(meth)acrylate, and polyethylene glycol mono methacrylate.
• the primary additive may be "non-reactive" meaning that it does not contain polymerizable vinyl groups.
• the imageable layer can also include a "secondary additive" that is a poly( vinyl alcohol), a poly( vinyl pyrrolidone), poly( vinyl imidazole), or polyester in an amount of up to and including 20 weight % based on the total dry weight of the imageable layer.
• a "secondary additive" that is a poly( vinyl alcohol), a poly( vinyl pyrrolidone), poly( vinyl imidazole), or polyester in an amount of up to and including 20 weight % based on the total dry weight of the imageable layer.
• color developers we mean to include monomelic phenolic compounds, organic acids or metal salts thereof, oxybenzoic acid esters, acid clays, and other compounds described for example in U.S. Patent Application Publication 2005/0170282 (Inno et al.).
• phenolic compounds include but are not limited to, 2,4-dihydroxybenzophenone, 4,4'-isopropylidene-diephenol (Bisphenol A), p-t-butylphenol, 2,4,-dinitrophenol, 3,4-dichlorophenol, 4,4'-methylene-bis(2,6'-di-t-butylphenol),/?-phenylphenol, 1 , 1 -bis(4-hydroxyphenyl)cyclohexane, 1 , 1 -bis(4-hydroxyphenyl)-2-ethylhexene, 2,2-bis(4-hydroxyphenyl)butane, 2,2'-methylenebis(4-t-butylphenol), 2,2'- methylenebis( ⁇ -phenyl-p-cresol)thiodiphenol, 4,4'-thiobis(6-t-butyl-m- cresol)sulfonyldiphenol, /7-butylphenol-formalin condensate
• useful organic acids or salts thereof include but are not limited to, phthalic acid, phthalic anhydride, maleic acid, benzoic acid, gallic acid, o-toluic acid, p-toluic acid, salicylic, 3-t-butylsalicylic, 3,5-di-3-t- butylsalicylic acid, 5- ⁇ -methylbenzylsalicylic acid, 3,5-bis( ⁇ - methylbenzyl)salicylic acid, 3-t-octylsalicylic acid, and their zinc, lead, aluminum, magnesium, and nickel salts.
• oxybenzoic acid esters examples include but are not limited to, ethyl /7-oxybenzoate, butyl /?-oxybenzoate, heptylp- oxybenzoate, and benzyl />-oxybenzoate.
• Such color developers may be present in an amount of from 0.5 to 5 weight %, based on total imageable layer dry weight.
• the imageable layer can also include a variety of optional compounds including but not limited to, dispersing agents, humectants, biocides, plasticizers, surfactants for coatability or other properties, viscosity builders, pH adjusters, drying agents, defoamers, preservatives, antioxidants, development aids, rheology modifiers or combinations thereof, or any other addenda commonly used in the lithographic art, in conventional amounts.
• Useful viscosity builders include hydroxypropyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and poly( vinyl pyrrolidones).
• the imageable elements can be formed by suitable application of a radiation-sensitive composition as described above to the substrate of this invention to form an imageable layer.
• This substrate can be treated or coated in various ways as described below prior to application of the radiation-sensitive composition to improve hydrophilicity.
• the element can include what is conventionally known as an overcoat (such as an oxygen impermeable topcoat) applied to and disposed over the imageable layer for example, as described in WO 99/06890 (Pappas et al.).
• Such overcoat layers can comprise a water-soluble polymer such as a poly( vinyl alcohol), poly( vinyl pyrrolidone), poly(ethyleneimine), or poly( vinyl imidazole), copolymers of two or more of vinyl pyrrolidone, ethyleneimine, and vinyl imidazole, and mixtures of such polymers, and generally have a dry coating weight of at least 0.1 and up to and including 4 g/m 2 in which the water-soluble polymer(s) comprise at least 90% and up to 100% of the dry weight of the overcoat.
• this overcoat is not present, and the imageable layer is the outermost layer of the imageable element.
• the radiation-sensitive composition can be applied to the substrate as a solution or dispersion in a coating liquid using any suitable equipment and procedure, such as spin coating, knife coating, gravure coating, die coating, slot coating, bar coating, wire rod coating, roller coating, or extrusion hopper coating.
• the composition can also be applied by spraying onto a suitable support (such as an on-press printing cylinder).
• a suitable support such as an on-press printing cylinder.
• the radiation-sensitive composition is applied and dried to form an imageable layer and an overcoat formulation is applied to that layer.
• Illustrative of such manufacturing methods is mixing the radically polymerizable component, primary polymeric binder, initiator composition including iodonium cation and borate anion, infrared radiation absorbing compound, and any other components of the radiation-sensitive composition in a suitable organic solvent or mixtures thereof [such as methyl ethyl ketone (2- butanone), methanol, ethanol, 1 -methoxy-2-propanol, /so-propyl alcohol, acetone, ⁇ -butyrolactone, /i-propanol, tetrahydrofuran, and others readily known in the art, as well as mixtures thereof], applying the resulting solution to a substrate, and removing the solvent(s) by evaporation under suitable drying conditions.
• a suitable organic solvent or mixtures thereof such as methyl ethyl ketone (2- butanone), methanol, ethanol, 1 -methoxy-2-propanol, /so-propyl alcohol,
• the coating weight of the imageable layer is generally at least 0.1 and up to and including 5 g/m 2 or at least 0.5 and up to and including 3.5 g/m 2 .
• Layers can also be present under the imageable layer, on the substrate, to enhance developability or to act as a thermal insulating layer.
• the underlying layer should be soluble or at least dispersible in the processing solution and typically have a relatively low thermal conductivity coefficient.
• the various layers may be applied by conventional extrusion coating methods from melt mixtures of the respective layer compositions. Typically such melt mixtures contain no volatile organic solvents.
• Intermediate drying steps may be used between applications of the various layer formulations to remove solvent(s) before coating other formulations. Drying steps at conventional times and temperatures may also help in preventing the mixing of the various layers.
• the imageable element can be enclosed in water-impermeable material that substantially inhibits the transfer of moisture to and from the imageable element as described in U.S. Patent 7,175,969 (noted above) that is cited herein by reference.
• the imageable element is exposed to a suitable source of imaging or exposing radiation, such as near-infrared or infrared radiation, depending upon the radiation absorbing compound present in the radiation- sensitive composition, at a wavelength of from 700 to 1500 run.
• imaging can be carried out using imaging or exposing radiation, such as from an infrared laser at a wavelength of at least 700 ran and up to and including 1400 run and typically at least 750 ran and up to and including 1250 ran. Imaging can be carried out using imaging radiation at multiple wavelengths at the same time if desired.
• the laser used to expose the imageable element is usually a diode laser, because of the reliability and low maintenance of diode laser systems, but other lasers such as gas or solid-state lasers may also be used.
• the combination of power, intensity and exposure time for laser imaging would be readily apparent to one skilled in the art.
• high performance lasers or laser diodes used in commercially available imagesetters emit infrared radiation at a wavelength of at least 800 ran and up to and including 850 nm or at least 1060 and up to and including 1120 nm.
• the imaging apparatus can function solely as a platesetter or it can be incorporated directly into a lithographic printing press. In the latter case, printing may commence immediately after imaging and development, thereby reducing press set-up time considerably.
• the imaging apparatus can be configured as a flatbed recorder or as a drum recorder, with the imageable member mounted to the interior or exterior cylindrical surface of the drum.
• An example of an useful imaging apparatus is available as models of Kodak ® Trendsetter platesetters available from Eastman Kodak Company (Burnaby, British Columbia, Canada) that contain laser diodes that emit near infrared radiation at a wavelength of 830 nm.
• imaging sources include the Crescent 42T Platesetter that operates at a wavelength of 1064 nm (available from Gerber Scientific, Chicago, IL) and the Screen PlateRite 4300 series or 8600 series platesetter (available from Screen, Chicago, IL).
• Additional useful sources of radiation include direct imaging presses that can be used to image an element while it is attached to the printing plate cylinder.
• An example of a suitable direct imaging printing press includes the Heidelberg SM74-DI press (available from Heidelberg, Dayton, OH).
• Imaging with infrared radiation can be carried out generally at imaging energies of at least 30 mJ/cm 2 and up to and including 500 mJ/cm 2 , and typically at least 50 and up to and including 300 mJ/cm 2 depending upon the sensitivity of the imageable layer.
• thermoresistive head thermal printing head
• thermal printing described for example in U.S. Patent 5,488,025 (Martin et al.).
• Thermal print heads are commercially available (for example, a Fujitsu Thermal Head FTP-040 MCSOOl and TDK Thermal Head F415 HH7-1089).
• Imaging of the imageable element produces an imaged element that comprises a latent image of imaged (exposed) and non-imaged (non-exposed) regions.
• Developing the imaged element with a suitable developer or processing solution removes predominantly only the non-exposed regions of the various layers and reveals the hydrophilic surface of the substrate.
• the imageable elements are "negative-working" (for example, negative-working lithographic printing plate precursors).
• the exposed (or imaged) regions accept ink while the substrate in the non-exposed (or non-imaged) regions repels ink.
• Development can be carried out for a time sufficient off-press to remove the non-imaged (non-exposed) regions of the imaged element, but not long enough to remove the exposed regions.
• non-imaged (non-exposed) regions of the imageable layer are described as being “soluble” or “removable” in the developer or processing solution because they are removed, dissolved, or dispersed within the developer or processing solution more readily than the imaged exposed) regions.
• soluble also means “dispersible”.
• Useful developers for off-press development include organic solvent-containing alkaline developers that generally have a pH below 12 and are generally single-phase solutions of one or more organic solvents that are miscible with water, such as 2-ethylethanol and 2-butoxyethanol.
• Representative solvent- containing alkaline developers include ND-I Developer, 955 Developer, 956
• the developer is applied to the imaged element by rubbing or wiping the outer layer with an applicator containing the developer.
• the imaged element can be brushed with the developer or the developer may be applied by spraying the outer layer with sufficient force to remove the exposed regions.
• the imaged element can be immersed in the developer, hi all instances, a developed image is produced, particularly in a lithographic printing plate having a hydrophilic aluminum-containing substrate of this invention.
• the imaged element can be rinsed with water and dried in a suitable fashion.
• the dried element can also be treated with a conventional gumming solution (preferably gum arabic).
• a postbake operation can be carried out, with or without a blanket or floodwise exposure to UV or visible radiation.
• the imaged and developed element can be baked in a postbake operation to increase run length of the resulting printing plate. Baking can be carried out, at from 220 0 C to 240 0 C for from 7 to 10 minutes, or at 120 0 C for 30 minutes. Alternatively, a blanket UV or visible radiation exposure can be carried out, without a postbake operation.
• a lithographic ink and fountain solution can be applied to the printing surface of the imaged element for printing.
• the exposed (non-removed) regions of the outermost layer take up ink and the hydrophilic surface of the substrate revealed by the imaging and development process takes up the fountain solution.
• the ink is then transferred to a suitable receiving material (such as cloth, paper, metal, glass, or plastic) to provide a desired impression of the image thereon.
• a suitable receiving material such as cloth, paper, metal, glass, or plastic
• an intermediate "blanket” roller can be used to transfer the ink from the imaged member to the receiving material.
• the imaged members can be cleaned between impressions, if desired, using conventional cleaning means and chemicals.
• the imaged elements can be processed off-press using a single processing solution that both "develops" the imaged precursors by removing predominantly only the non-exposed regions (development) and also provides a protective layer or coating over the entire imaged and developed surface.
• the processing solution can behave somewhat like a gum that is capable of protecting the lithographic image on the printing plate against contamination or damage (for example, from oxidation, fingerprints, dust, or scratches).
• the processing solution is an aqueous solution that generally has a pH greater than 2 and up to 11.5, and typically from 6 to 11, or from 6 to 10.5, as adjusted using a suitable amount of an acid or base.
• this single processing solution can be applied to the imaged precursor by rubbing, spraying, jetting, dipping, immersing, coating, or wiping the outer layer with the single processing solution or contacting the imaged precursor with a roller, impregnated pad, or applicator containing the single processing solution.
• the imaged element can be brushed with the processing solution, or the processing solution can be poured onto or applied by spraying the imaged surface with sufficient force to remove the exposed regions using a spray nozzle system as described for example in [0124] of EP 1, 788,431A2 (noted above).
• the imaged element can be immersed in the single processing solution and rubbed by hand or with an apparatus.
• the single processing solution can also be applied in a processing unit (or station) as a component of a suitable apparatus that has at least one roller for rubbing or brushing the precursor while the single processing solution is applied.
• a processing unit or station
• the exposed regions of the imaged layer may be removed from the substrate more completely and quickly.
• Residual single processing solution may be removed (for example, using a squeegee or nip rollers) or left on the resulting printing plate (and dried) without any rinsing step. It is desirable that processing be carried out using processor systems and apparatus that allow the processing solution to reside on the imaged precursor for sufficient time of interaction between the processing solution and the precursor imaged coatings before mechanical means (such as brush or plush rollers) are used.
• the imaged negative- working imageable element can be developed "on-press" as described in more detail below.
• a post-exposure baking step is omitted.
• On- press development avoids the use of alkaline developing solutions typically used in conventional processing apparatus.
• the imaged element is mounted on press wherein the unexposed regions in the imageable layer are removed by a suitable fountain solution, lithographic printing ink, or a combination of both, when the initial printed impressions are made.
• Typical ingredients of aqueous fountain solutions include pH buffers, desensitizing agents, surfactants and wetting agents, humectants, low boiling solvents, biocides, antifoaming agents, and sequestering agents.
• a representative example of a fountain solution is Varn Litho Etch 142W + Varn PAR (alcohol sub) (available from Varn International, Addison, IL).
• the fountain solution is taken up by the non-imaged regions, that is, the surface of the hydrophilic substrate revealed by the imaging and development steps, and ink is taken up by the imaged (non-removed) regions of the imaged layer.
• the ink is then transferred to a suitable receiving material (such as cloth, paper, metal, glass, or plastic) to provide a desired impression of the image thereon.
• a suitable receiving material such as cloth, paper, metal, glass, or plastic
• an intermediate “blanket” roller can be used to transfer the ink from the imaged member to the receiving material.
• the imaged members can be cleaned between impressions, if desired, using conventional cleaning means.
• Byk ® 336 is a surfactant that is available from Byk Chemie (Wallingford, CT).
• Blue 63 is a spirolactone leuco dye from Yamamoto Chemicals (Japan) having the following structure:
• Graft Polymer A was a graft copolymer of acrylonitrile/styrene/poly(ethylene glycol), 70/20/10 used at a 24% solids in n- propanol/water (76/24). This polymer is described as Copolymer 10 in U.S. Patent 7,261 ,998 (Hayashi et al.).
• Initiator A is bis(4-t-butylphenyl) iodonium tetraphenylborate.
• IR Dye A is a cyanine infrared radiation absorbing dye having the following structure:
• Irgacure ® 250 is iodonium, (4-methylphenyl)[4-(2- methylpropyl)phenyl]-, hexafluorophosphate that is available from Ciba Specialty Chemicals (Tarrytown, NY).
• Klucel E is a hydroxypropyl cellulose material that is available from Hercules Inc. (Wilmington, DE).
• Masurf ® 1520 is a fluorosurfactant that was obtained from Mason Chemicals (Arlington Heights, IL).
• MEHQ represents hydroquinone monomethyl ether (also known as 4-methoxyphenol).
• MEK represents methyl ethyl ketone.
• Oligomer A is a urethane acrylate prepared by reacting
• DESMODUR ® NlOO an aliphatic polyisocyanate resin based on hexamethylene diisocyanate from Bayer Corp., Milford, CT
• hydroxyethyl acrylate and pentaerythritol triacrylate 800 wt. % solution in 2-butanone
• Sartomer SR494 is ethoxylated pentaerythritol tefraacrylate that was obtained from Sartomer Company, Inc. (Exton, PA).
• Sipomer PAM-100 is an ethylene glycol methacrylate phosphate having 4-5 ethylene glycol units that was obtained from Rhodia (Cranbury, NJ).
• SLE-A is a polyethylene glycol) diacid (MW-600).
• SLE-B is an l-[N-[poly(3-allyloxy-2-hydroxypropyl)]-2- aminoethyl]-2-imidazlidinone.
• Step 2 The intermediate from Step 1 (52.8 g, 0.022 equivalents), 50.0 g of
• MEK dried over molecular sieve
• 0.05 g of MEHQ were charged into a four- neck 250 ml flask, equipped with a heating mantle, temperature controller, mechanical stirrer, condenser, pressure equalized addition funnel, and nitrogen inlet.
• the reaction mixture was heated to 30 0 C and 4.95 g of 3-(triethoxysilyl) propyl isocyanate (0.02 equivalents) was added in ten minutes. Reaction mixture was maintained at 30 0 C for two hours. Completion of the reaction was determined by the disappearance of the isocyanate infrared absorption band at 2275cm "1 .
• MEK was removed under vacuum (100 mm) and heat (45 0 C). About 55 g of sticky material was obtained that was subsequently dissolved in water (10% wt solution) for further use. The 10% aqueous solution was clear.
• Step 2 The intermediate from Step 1 (35.5 g, 0.033 equiv.), 59.2 g of
• Step 2 The intermediate from Step 1 (56.9 g, 0.0275 equivalents), 63.4 g of MEK (dried over molecular sieve), 0.05 g of MEHQ, and 0.315 g OfD 22 (Dibutyl Tin Dilaurate) were charged into a four-neck 250 ml flask, equipped with a heating mantle, temperature controller, mechanical stirrer, condenser, pressure equalized addition funnel, and nitrogen inlet. The reaction mixture was heated to 60 0 C and 6.18 g of 3-(triethoxysilyl) propyl isocyanate (0.025 equivalents) were added over twenty minutes. The reaction mixture was maintained at 60 0 C for 3 hours.
• Step 2 The intermediate of Step 1 (51.8 g, 0.033 equivalents), 110.6 g of
• reaction mixture was cooled to room temperature. Triethylamine hydrochloride salt was removed and 0.056 g of MEHQ was added. MEK was removed under vacuum (100 mm) and heat (45 0 C) to provide 105 g of an intermediate.
• Step 2 The intermediate from Step 1 (58.8 g, 0.055 equivalents), 71.2 g of
• Substrate U an aluminum lithographic substrate without an interlayer.
• a 0.30 mm thick aluminum sheet was alkaline cleaned, electrochemically grained with hydrochloric acid, etched in a caustic solution, anodized in sulfuric acid, and thoroughly rinsed and dried using conventional procedures.
• the resultant non- post-treated Substrate U had a D nUn of about 0.36 (K), oxide weight of about 2.5 g/m 2 , and a Ra roughness of about 0.58 ⁇ m.
• the oxide layer had a thickness of about 1 ⁇ m.
• the Substrate U was found to repel ink when tested on commercial ABDick printing press.
• Substrate Example 1 Preparation of Substrate A (IC-A interlayer on Substrate U): This example illustrates the preparation of Substrate A.
• An interlayer coating formulation was prepared by dissolving IC-A (4.55 g, 10% in water) and Masurf ® 1520 (1.36 g, 1% in water) in isopropyl alcohol (4.18 g) and water (89.91 g). This formulation was slot coated onto a sample of Substrate U described above and was dried on a rotating drum at about 200 0 F (93.3°C) for 80 seconds to provide a thin interlayer with a coating weight of about 0.06 g/m 2 . The resulting substrate was found to repel ink when tested on a commercial ABDick printing press.
• Substrate Example 2 Preparation of Substrate Al (IC-Al interlayer on Substrate U):
• This example illustrates the preparation of Substrate A.
• An interlayer coating formulation was prepared by dissolving IC-Al (4.55 g, 10% in water) and Masurf ® 1520 (1.36 g, 1% in water) in isopropyl alcohol (4.18 g) and water (89.91 g). This formulation was coated onto a sample of Substrate U described above and was dried on a rotating drum at about 200 0 F (93.3°C) for 80 seconds to provide a thin interlayer with a coating weight of about 0.06 g/m 2 . The resulting substrate was found to repel ink when tested on a commercial ABDick printing press.
• Comparative Substrate Example 2 Preparation of Substrate B (an IC-B interlayer on Substrate U): This example illustrates the preparation of Substrate B.
• a coating formulation was prepared by dissolving IC-B (4.55 g, 10% in water) and Masurf ® 1520 (1.36 g, 1% in water) in isopropyl alcohol (4.18 g) and water (89.91 g). This formulation was slot coated onto as sample of Substrate U that is described above, and was dried on a rotating drum at about 93.3 0 C for 80 seconds to provide a thin interlayer with a dry coating weight of about 0.06 g/m 2 . The resulting substrate was found to repel ink when tested on a commercial ABDick printing press.
• Comparative Substrate Example 3 Preparation of Substrate C (an IC-C inter layer on Substrate U): This example illustrates the preparation of Substrate C.
• a coating formulation was prepared by dissolving IC-C (4.55 g, 10% in water) and Masurf ® 1520 (1.36 g, 1% in water) in isopropyl alcohol (4.18 g) and water (89.91 g). This formulation was slot coated onto a sample of Substrate U that is described above, and was dried on a rotating drum at about 93.3 0 C for 80 seconds to provide a thin interlayer with a dry coating weight of about 0.06 g/m 2 . The resulting substrate was found to repel ink when tested on a commercial ABDick printing press.
• Comparative Substrate Example 4 Preparation of Substrate D (an IC-D interlayer on Substrate U):
• a coating formulation was prepared by dissolving IC-D (4.55 g, 10% in water) and Masurf ® 1520 (1.36 g, 1% in water) in isopropyl alcohol (4.18 g) and water (89.91 g). This formulation was slot coated onto a sample of Substrate U that is described above, and was dried on a rotating drum at about 93.3 0 C for 80 seconds to provide a thin interlayer with a dry coating weight of about 0.06 g/m 2 . The resulting substrate was found to repel ink when tested on a commercial ABDick printing press.
• a coating formulation was prepared by dissolving IC-E (4.55 g, 10% in water) and Masurf ® 1520 (1.36 g, 1% in water) in isopropyl alcohol (4.18 g) and water (89.91 g). This formulation was slot coated onto a sample of Substrate U that is described above, and was dried on a rotating drum at about 93.3°C for 80 seconds to provide a thin interlayer with a dry coating weight of about 0.06 g/m 2 . The resulting substrate accepted ink when tested on a commercial ABDick printing press, and was removed for further testing.
• the imageable layer coating composition shown below in TABLE I was prepared to give a 4.5% w/w solution in a solvent mixture of 70% n- propanol, 20% MEK, and 10% water.
• the composition was applied to samples of Substrate A using a slot coater at 2.5 craVft 2 (26.9 cm 3 /m 2 ) and dried to give a dry imageable layer coverage of 1.0 g/m 2 .
• the coating drum temperature was 82.2 0 C and the duration was 80 seconds.
• an on-press developable imageable element (lithographic printing plate precursor) was obtained. Samples of the imageable elements were treated under various conditions in order to accelerate the effects of plate ageing.
• the imageable elements were wrapped in interleaving and foil and then treated for 5 days at 48°C (dry aging test).
• the imageable elements were hung in a humidity chamber for 5 days at 38°C and 80% relative humidity (humidity aging test)
• the imageable elements were placed at room temperature in dark (inside a cardboard box) for 5-10 days (natural aging test).
• the imageable elements (A) in this example exhibited very good development (background clean) after both dry aging and humidity aging tests. In a press run length test, the imageable elements (A) provided
• the imageable layer coating composition shown below in TABLE I was prepared to give a 4.5% w/w solution in a solvent mixture of 70% n- propanol, 20% MEK, and 10% water.
• the composition was applied to samples of Substrate Al using a slot coater at 2.5 cm 3 /ft 2 (26.9 cmVm 2 ) and dried to give a dry imageable layer coverage of 1.0 g/m 2 .
• the coating drum temperature was 82.2 0 C and the duration was 80 seconds. After cooling to room temperature, an on-press developable imageable element (lithographic printing plate precursor) was obtained.
• Samples of the imageable elements were treated under various conditions in order to accelerate the effects of plate ageing.
• the imageable elements were wrapped in interleaving and foil and then treated for 5 days at 48°C (dry aging test).
• the imageable elements were hung in a humidity chamber for 5 days at 38°C and 80% relative humidity (humidity aging test).
• the imageable elements were placed at room temperature in dark (inside a cardboard box) for 5-10 days (natural aging test).
• the imageable elements (Al) in this example exhibited very good development (background clean) after both dry aging and humidity aging tests. hi a press run length test, the imageable elements (Al) provided 17,000 good impressions on a Komori press using a wear ink containing 1.5% calcium carbonate, after exposing at 150 mJ/cm 2 at 15 watts on the Kodak ® Trendsetter 3244x platesetter.
• Each of the imageable layer coating compositions shown below in TABLE I was prepared to give a 4.5% w/w solution in a solvent mixture of 70% n-propanol, 20% MEK, and 10% water.
• Each of the compositions was applied to samples of Substrates U, B, C and D respectively, using a slot coater at 2.5 Cm 3 ZfT 2 (26.9 cm 3 /m 2 ) and dried to give a dry imageable layer coverage of 1.0 g/m 2 .
• the coating drum temperature was 82.2 0 C and the duration was 80 seconds. After cooling to room temperature, four imageable elements (lithographic printing plate precursors) were obtained.
• Imageable elements (U) and (D) in this example showed very poor development (strong background retaining) after both dry aging and humidity aging tests.
• the imageable elements (B) and (C) in this example showed good development (background clean) after both dry aging test and humidity aging test.
• the imageable elements (B) and (C) provided only 15,000 and 10,000 good impressions, respectively, on a Komori press with a wear ink containing 1.5% calcium carbonate, after exposing at 150 mJ/cm 2 at 15 watts on a Kodak ® Trendsetter 3244x platesetter.

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