EP1826022B1 - Procédé pour la production d'un support pour plaque d'impression lithographique - Google Patents

Procédé pour la production d'un support pour plaque d'impression lithographique Download PDF

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Publication number
EP1826022B1
EP1826022B1 EP06110469A EP06110469A EP1826022B1 EP 1826022 B1 EP1826022 B1 EP 1826022B1 EP 06110469 A EP06110469 A EP 06110469A EP 06110469 A EP06110469 A EP 06110469A EP 1826022 B1 EP1826022 B1 EP 1826022B1
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EP
European Patent Office
Prior art keywords
group
acid
pps
printing plate
coating
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Expired - Fee Related
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EP06110469A
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German (de)
English (en)
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EP1826022A1 (fr
Inventor
Paola Campestrini
Herman Terryn
Thanasis Dimogerontakis
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Agfa NV
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Agfa Graphics NV
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Priority to EP06110469A priority Critical patent/EP1826022B1/fr
Priority to DE602006003856T priority patent/DE602006003856D1/de
Priority to PCT/EP2007/051274 priority patent/WO2007099024A1/fr
Priority to US12/280,261 priority patent/US20090084683A1/en
Priority to CN200780006955.6A priority patent/CN101389488B/zh
Publication of EP1826022A1 publication Critical patent/EP1826022A1/fr
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    • 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
    • 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
    • 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
    • B41N1/00—Printing plates or foils; Materials therefor
    • B41N1/04—Printing plates or foils; Materials therefor metallic
    • B41N1/08—Printing plates or foils; Materials therefor metallic for lithographic printing
    • B41N1/083—Printing plates or foils; Materials therefor metallic for lithographic printing made of aluminium or aluminium alloys or having such surface layers
    • 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
    • B41N3/034—Chemical or electrical pretreatment characterised by the electrochemical treatment of the aluminum support, e.g. anodisation, electro-graining; Sealing of the anodised layer; Treatment of the anodic layer with inorganic compounds; Colouring of the anodic layer
    • 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
    • B41C1/1025—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 using materials comprising a polymeric matrix containing a polymeric particulate material, e.g. hydrophobic heat coalescing particles
    • 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
    • B41C2210/02—Positive working, i.e. the exposed (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
    • B41C2210/04—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
    • B41C2210/06—Developable by an alkaline 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
    • B41C2210/08—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
    • B41C2210/10—Developable by an acidic 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
    • 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
    • B41C2210/26—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 not involving carbon-to-carbon unsaturated bonds
    • B41C2210/262—Phenolic condensation polymers, e.g. novolacs, resols
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
    • B41M5/36—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using a polymeric layer, which may be particulate and which is deformed or structurally changed with modification of its' properties, e.g. of its' optical hydrophobic-hydrophilic, solubility or permeability properties
    • B41M5/366—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using a polymeric layer, which may be particulate and which is deformed or structurally changed with modification of its' properties, e.g. of its' optical hydrophobic-hydrophilic, solubility or permeability properties using materials comprising a polymeric matrix containing a polymeric particulate material, e.g. hydrophobic heat coalescing particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
    • B41M5/36—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using a polymeric layer, which may be particulate and which is deformed or structurally changed with modification of its' properties, e.g. of its' optical hydrophobic-hydrophilic, solubility or permeability properties
    • B41M5/368—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using a polymeric layer, which may be particulate and which is deformed or structurally changed with modification of its' properties, e.g. of its' optical hydrophobic-hydrophilic, solubility or permeability properties involving the creation of a soluble/insoluble or hydrophilic/hydrophobic permeability pattern; Peel development

Definitions

  • the present invention relates to a method for making a lithographic printing plate support and to a method for making a heat- and/or light sensitive, lithographic printing plate comprising said support.
  • Lithographic printing presses use a so-called printing master such as a printing plate which is mounted on a cylinder of the printing press.
  • the master carries a lithographic image on its surface and a print is obtained by applying ink to said image and then transferring the ink from the master onto a receiver material, which is typically paper.
  • ink as well as an aqueous fountain solution (also called dampening liquid) are supplied to the lithographic image which consists of oleophilic (or hydrophobic, i.e. ink-accepting, water-repelling) areas as well as hydrophilic (or oleophobic, i.e. water-accepting, ink-repelling) areas.
  • driographic printing the lithographic image consists of ink-accepting and ink-abhesive (ink-repelling) areas and during driographic printing, only ink is supplied to the master.
  • Printing masters are generally obtained by the image-wise exposure and processing of an imaging material called plate precursor.
  • plate precursor an imaging material
  • heat-sensitive printing plate precursors have become very popular in the late 1990s.
  • thermal materials offer the advantage of daylight stability and are especially used in the so-called computer-to-plate method wherein the plate precursor is directly exposed, i.e. without the use of a film mask.
  • the material is exposed to heat or to infrared light and the generated heat triggers a (physico-)chemical process, such as ablation, polymerization, insolubilization by cross linking of a polymer, heat-induced solubilization, or by particle coagulation of a thermoplastic polymer latex.
  • a (physico-)chemical process such as ablation, polymerization, insolubilization by cross linking of a polymer, heat-induced solubilization, or by particle coagulation of a thermoplastic polymer latex.
  • Thermal processes which enable plate making without wet processing are for example based on ablation of one or more layers of the coating. At the exposed areas the surface of an underlying layer is revealed which has a different affinity towards ink or fountain than the surface of the unexposed coating; the image (printing) and non-image or background (non-printing) areas are obtained.
  • Another type of printing plates based on thermal processes requiring no wet processing step are for example plates based on switching - i.e. plates of which the surface is irreversibly changed from a hydrophilic surface to a hydrophobic surface or vice versa upon exposure to heat and/or light.
  • switching - i.e. plates of which the surface is irreversibly changed from a hydrophilic surface to a hydrophobic surface or vice versa upon exposure to heat and/or light.
  • switchable polymer systems are based on different working mechanism such as for example masking/demasking of a polar group or destruction/ generation of charge.
  • the most popular thermal plates form an image by a heat-induced solubility difference in an alkaline developer between exposed and non-exposed areas of the coating.
  • the coating typically comprises an oleophilic binder, e.g. a phenolic resin, of which the rate of dissolution in the developer is either reduced (negative working) or increased (positive working) by the image-wise exposure.
  • the solubility differential leads to the removal of the non-image (non-printing) areas of the coating, thereby revealing the hydrophilic support, while the image (printing) areas of the coating remain on the support.
  • Typical examples of such plates are described in e.g.
  • Negative working plate precursors which do not require a pre-heat step may contain an image-recording layer that works by heat-induced particle coalescence of a thermoplastic polymer latex, as described in e.g. EP-As 770 494 , 770 495 , 770 496 and 770 497 .
  • EP-As 770 494 , 770 495 , 770 496 and 770 497 disclose a method for making a lithographic printing plate comprising the steps of (1) image-wise exposing an imaging element comprising hydrophobic thermoplastic polymer particles dispersed in a hydrophilic binder and a compound capable of converting light into heat, (2) and developing the image-wise exposed element by applying fountain and/or ink.
  • US 5,728,503 provides a grained and anodized aluminum support for a light sensitive printing plate having a substantially uniform topography comprising peaks and valleys and surface roughness parameters Ra (0.10-0.5 ⁇ m), Rt (0-6 ⁇ m), Rp (0-4 ⁇ m) and Rz (0-5 ⁇ m ).
  • EP 1,400,351 discloses a lithographic printing plate precursor containing an aluminum support and a photosensitive layer containing an alkali-soluble resin and an infrared absorber, wherein the photosensitive layer has a coating weight of 0.5 to 3 g/m 2 and a thickness distribution with a maximum relative standard deviation of 20%.
  • WO 02/01291 discloses a lithographic plate comprising on a roughened substrate a substantially conformal radiation-sensitive layer; i.e. the surface of the radiation-sensitive layer has peaks and valleys substantially corresponding to the major peaks and valleys of the microscopic surface of the roughened substrate. Tackiness, block resistance and press durability of the plate are improved.
  • Us 6,912,956 discloses a printing plate material comprising a substrate having a center line average surface roughness Ra of 0.2 to 1.0 ⁇ m and an oil-retention volume A2 of 1 to 10, and provided thereon a component layer onto which an image is capable of being recorded by imagewise exposure with an infrared laser.
  • US 4,545,866 discloses electrochemically graining the surface of an aluminum support with an electrolytic solution comprising 1000 to 40000 ppm of nitric acid and 50 to 4000 ppm of sulfuric acid.
  • EP 036,672 discloses electrolytically etching of aluminum in an aqueous electrolytic solution containing hydrochloric acid and citric acid or malic acid at a bath temperature of 10 to 40 °C.
  • US 4,671,859 and US 4,376,124 disclose a process for the electrochemical graining of aluminum in which an electrolyte composition containing ⁇ -ketones is employed.
  • US 4,482,434 discloses the roughening of aluminum by applying an electrolyte solution under the action of an alternating current having a frequency in the range from 0.3 to 15 Hz.
  • the use of aluminum substrates as supports for lithographic printing plates requires that they undergo several treatments such as for example graining and anodizing.
  • Lithographic supports are roughened or grained to improve the adhesion of an imaging layer to the support and anodizing may be carried out to improve the abrasion resistance and water retention of the support.
  • the type of grains obtained, especially their size and distribution over the surface, highly influence the lithographic behaviour of the related printing plate.
  • the pits on the aluminum surface have to be deep enough to provide sufficient adhesion of the coating layer, they should be evenly distributed over the surface and they should be uniform in size. The pits size and distribution should provide a good balance between adhesion properties of the coating at the image areas (i.e.
  • a method for making a lithographic printing plate which comprises the steps of: (i) providing a printing plate precursor as described above; (ii) exposing the obtained printing plate precursor to heat and/or light and (iii) optionally processing said exposed precursor with an aqueous liquid.
  • the lithographic printing plate support according to the method of the present invention is an aluminum support.
  • the surface of the aluminum support is grained and anodized aluminum.
  • the support may be a sheet-like material such as a plate or it may be a cylindrical element such as a sleeve which can be slid around a print cylinder of a printing press.
  • the aluminum is preferably anodized by means of anodizing techniques employing sulphuric acid and/or a sulphuric acid/phosphoric acid mixture.
  • anodizing techniques employing sulphuric acid and/or a sulphuric acid/phosphoric acid mixture.
  • the aluminium support By anodising the aluminium support, its abrasion resistance and hydrophilic nature are improved.
  • the microstructure as well as the thickness of the Al 2 O 3 layer are determined by the anodising step, the anodic weight (g/m 2 Al 2 O 3 formed on the aluminium surface) varies between 1 and 8 g/m 2 .
  • Methods of anodizing are known in the art and are for example disclosed in GB 2,088,901 .
  • graining By graining (or roughening) the aluminium support, both the adhesion of the printing image and the wetting characteristics of the non-image areas are improved. According to the present invention, it was surprisingly found that graining the aluminum support in an electrolyte solution comprising an effective concentration of a benzoic acid derivative or a sulphonic acid derivative, results in a surface with uniformly distributed, fine pits. The graining morphology of the surface was determined following a newly developed threshold procedure which is disclosed further in the description.
  • the surface of the support is grained using an aqueous electrolyte solution comprising an effective concentration of a benzoic acid derivative or a sulphonic acid derivative and preferably at least one of the following chemicals: HNO 3 , HCl and/or H 3 PO 4 .
  • the electrolyte solution contains HCl and an effective concentration of a benzoic acid derivative or a sulphonic acid derivative.
  • the effective concentration of the benzoic acid derivative or the sulphonic acid derivative is at least 0.0001 mol/1.
  • concentration varies between 0.0001 mol/l and 0.2 mol/l, more preferably between 0.0001 mol/l and 0.1 mol/l, most preferably between 0.001 mol/l and 0.05 mol/l.
  • the concentration of HCl, HNO 3 and/or H 3 PO 4 in the electrolyte solution preferably varies between 1 g/l and 50 g/l; more preferably between 5 g/l and 30 g/l; most preferably between 7 g/l and 20 g/l.
  • a preferred benzoic acid derivative includes a benzoic acid such as ortho-, meta- or para-substituted benzoic acid or di- or tri-substituted benzoic acid, a phtalic acid, isophtalic acid, terephtalic acid, salicylic acid, benzoic anhydride, 1- naphtoic acid or 2- naphtoic acid; or salts or esters thereof and each of which may be substituted.
  • Suitable salts are for example sodium, potassium or ammonium salts.
  • a suitable ester is for example an optionally substituted alkyl benzoic acid wherein the alkyl group represents a straight, branched or cyclic alkyl group having up to 10 carbon atoms.
  • the benzoic acid derivative is an optionally substituted benzoic acid.
  • the substituents optionally present on the benzoic acid derivatives are selected from a halogen, a nitro group, a straight, branched or cyclic alkyl group having up to 10 carbon atoms, a hydroxyl group, an amino group, a sulphonic acid group, a methoxygroup, or combinations thereof.
  • a preferred sulphonic acid derivative includes a benzenesulphonic acid, benzenedisulphonic acid, pyridine sulphonic acid, naphthalene sulphonic acid, naphthalene disulphonic acid, alkyl sulphonic acid, alkylene sulphonic acid and quinoline sulphonic acid; or salts or esters thereof; and each of which may be substituted.
  • Suitable salts are for example sodium, potassium or ammonium salts.
  • a suitable ester is for example an optionally substituted alkyl ester of a sulphonic acid such as an optionally substituted alkyl benzenesulphonic acid or a pyridine alkyl sulphonic acid; wherein the alkyl group represents a straight, branched or cyclic alkyl group having up to 10 carbon atoms.
  • the sulphonic acid derivatives may be mono- (ortho, meta or para), di- or tri-substituted.
  • the substituents optionally present on the sulphonic acid derivatives include a halogen, an amino group, a nitro group, a hydroxyl group, a methoxygroup, a carboxylic acid group, an optionally substituted straight, branched or cyclic alkyl group having up to 10 carbon atoms, or combinations thereof.
  • the sulphonic acid derivative is an optionally substituted benzenesulphonic acid.
  • the graining may be carried out using alternating current at a voltage ranging for example from 5V to 50V, preferably from 20V to 40V for a period ranging from 5 to 120 seconds.
  • the current density ranges from 50 A/dm 2 to 200 A/dm 2 , more preferably from 80 A/dm 2 to 150 A/dm 2 .
  • the current charge preferably ranges from 300 C/dm 2 to 1500 C/dm 2 , more preferably from 500 C/dm 2 to 1050 C/dm 2 .
  • the electrolyte temperature may be at any suitable temperature but preferably ranges from 20°C to 55°C, more preferably from 30°C to 45°C.
  • the grained and anodized aluminum substrate of the present invention may be post-treated to further improve the hydrophilic properties of its surface.
  • the aluminum oxide surface may be silicated by treatment with a sodium silicate solution at elevated temperature, e.g. 95°C.
  • a phosphate treatment may be applied which involves treating the aluminum oxide surface with a phosphate solution that may further contain an inorganic fluoride.
  • the aluminum oxide surface may be rinsed with an organic acid and/or salt thereof, e.g. carboxylic acids, hydrocarboxylic acids, sulphonic acids or phosphonic acids, or their salts, e.g. succinates, phosphates, phosphonates, sulphates, and sulphonates.
  • a citric acid or citrate solution is preferred. This treatment may be carried out at room temperature or may be carried out at a slightly elevated temperature of about 30°C to 50°C.
  • a further interesting treatment involves rinsing the aluminum oxide surface with a bicarbonate solution. Still further, the aluminum oxide surface may be treated with polyvinylphosphonic acid, polyvinylmethylphosphonic acid, phosphoric acid esters of polyvinyl alcohol, polyvinylsulphonic acid, polyvinylbenzenesulphonic acid, sulfuric acid esters of polyvinyl alcohol, and acetals of polyvinyl alcohols formed by reaction with a sulfonated aliphatic aldehyde. It is further evident that one or more of these post treatments may be carried out alone or in combination.
  • the graining morphology of the surface was determined according to the following newly developed threshold procedure.
  • three dimensional images are recorded of the substrate which characterize the graining morphology surface or the roughness properties of the surface of said substrate. From these images several parameters that describe various aspects of the surface-morphology can be calculated. Tthe Bearing Ratio Analysis technique (see for example Wyko Surface Profilers Technical Reference Manual, September 1999, from Veeko, Metrology Group (pages 3-3 to 3-11 ) or US 2004/0103805 ), has been used for calculating these parameters.
  • the three dimensional images or surface profiles can be obtained by using a white-light interferometer from Veeco (NT3300, commercially available from Veeco Metology Group, Arizona, USA).
  • the histogram of the surface profile also called Amplitude Distribution Function (ADF) gives the probability that the profile of the surface has a certain height z at any xy position. In other words, the ADF gives the probability that a point on the surface profile at a randomly selected position xy, has a height of approximately z.
  • the bearing ratio curve is the mathematical integral of the ADF and each point on the bearing ratio curve has the physical significance of showing what fraction of a profile lies above a certain height. In other words, the bearing ratio curve shows the percentage of intercepted material by a plane parallel to the surface plane, versus the depth of that plane into the surface.
  • the heights C and D at the surface profile are determined in the R k -construction by identyfying the minimum secant slope.
  • the minimum secant slope is obtained by sliding a 40% window (of the 0 to 100% axis in Figure 3 ) across the bearing ratio curve (6). This window intersects the curve at two points, i.e. points A and B and the goal is to find the position where the slope between the two points is minimised.
  • a line (7) through points A and B is drawn and the intercepts on the ordinates at bearing ratio 0% and 100% yield respectively points C and D.
  • a new threshold procedure based on the parameters defined in the R k construction has been defined which enables to evaluate the pit size distribution.
  • Figure 4 For the evaluation of the pit size distribution, first of all the three dimensional interferometer image is thresholded at height D ( Figure 4).
  • Figure 4 is in fact a cross-section at height D of the aluminium surface and shows the pits at this height.
  • the gray-scale of Figure 4 relates to the depth of the pits and their distribution throughout the cross-section. Each pixel has a depth value that enables to create the grey-scale image.
  • the threshold enables to identify and separate objects, i.e. pits.
  • the pits are separated from each other using a convex-components analysis.
  • the area, depth, and volume of each single pit can then be calculated using appropiate software such as Matlab.
  • the area of a pit is calculated on the tresholded image by multiplying the number of pixels belonging to a pit with the physical area of one pixel. From these values the mean and standard deviation of the pit area, depth and volume at the threshold height can be calculated.
  • the pit depth obtained from this threshold procedure is corrected to the real depth by adding R k ( Figure 5 ).
  • the volume of the pit is also corrected by adding the volume of a cylinder having as area the calculated area of the pit (at level D) and as height Rk ( Figure 5 ).
  • the pits with a depth lower than R k + R pk are not identified as pits by this image analysis.
  • this threshold procedure enables to compare the size distribution of the deep pits of different substrates.
  • a method for making a lithographic printing plate precursor comprising the steps of providing a support as discussed in detail above, applying a coating solution comprising at least one heat- or light-sensitive imaging layer onto said support and than drying the obtained precursor.
  • the precursor can be negative or positive working, i.e. can form ink-accepting areas at exposed or at non-exposed areas respectively.
  • negative or positive working i.e. can form ink-accepting areas at exposed or at non-exposed areas respectively.
  • the imaging mechanism of thermal printing plate precursors can be triggered by direct exposure to heat, e.g. by means of a thermal head, or by the light absorption of one or more compounds in the coating that are capable of converting light, more preferably infrared light, into heat.
  • a first suitable example of a thermal printing plate precursor is a precursor based on heat-induced coalescence of hydrophobic thermoplastic polymer particles which are preferably dispersed in a hydrophilic binder, as described in e.g. EP 770 494 ; EP 770 495 ; EP 770 497 ; EP 773 112 ; EP 774 364 ; EP 849 090 , EP 1614538 , EP 1614539 EP 1614540 and unpublished European patent applications EP 05105378.3 , EP 05109781.4 , EP 05109782.2 , EP 05108920.9 and unpublished patent application PCT/EP2005/054585 .
  • the thermal printing plate precursor comprises a coating comprising an aryldiazosulfonate homo- or copolymer which is hydrophilic and soluble in the processing liquid before exposure to heat or UV light and rendered hydrophobic and less soluble after such exposure.
  • aryldiazosulfonate polymers are the compounds which can be prepared by homo- or copolymerization of aryldiazosulfonate monomers with other aryldiazosulfonate monomers and/or with vinyl monomers such as (meth)acrylic acid or esters thereof, (meth)acrylamide, acrylonitrile, vinylacetate, vinylchloride, vinylidene chloride, styrene, ⁇ -methyl styrene etc.
  • Suitable aryldiazosulfonate monomers are disclosed in EP-A 339393 , EP-A 507008 and EP-A 771645 and suitable aryldiazosulfonate polymers are disclosed in EP 507,008 , EP 960,729 , EP 960,730 and EP1,267,211 .
  • a further suitable thermal printing plate is positive working and relies on heat-induced solubilization of an oleophilic resin.
  • the oleophilic resin is preferably a polymer that is soluble in an aqueous developer, more preferably an aqueous alkaline developing solution with a pH between 7.5 and 14.
  • Preferred polymers are phenolic resins e.g. novolac, resoles, polyvinyl phenols and carboxy substituted polymers. Typical examples of these polymers are described in DE-A-4007428 , DE-A-4027301 and DE-A-4445820 .
  • the amount of phenolic resin present in the first layer is preferably at least 50% by weight, preferably at least 80% by weight relative to the total weight of all the components present in the first layer.
  • the oleophilic resin is preferably a phenolic resin wherein the phenyl group or the hydroxy group is chemically modified with an organic substituent.
  • the phenolic resins which are chemically modified with an organic substituent may exhibit an increased chemical resistance against printing chemicals such as fountain solutions or press chemicals such as plate cleaners.
  • EP-A 0 934 822 examples include EP-A 1 072 432 , US 5 641 608 , EP-A 0 982 123 , WO 99/01795 , EP-A 02 102 446 , EP-A 02 102 444 , EP-A 02 102 445 , EP-A 02 102 443 , EP-A 03 102 522 .
  • the coating may comprise a second layer that comprises a polymer or copolymer (i.e. (co)polymer) comprising at least one monomeric unit that comprises at least one sulfonamide group.
  • This layer is located between the layer described above comprising the oleophilic resin and the hydrophilic support.
  • a (co)polymer comprising at least one monomeric unit that comprises at least one sulfonamide group' is also referred to as "a sulphonamide (co)polymer”.
  • the sulphonamide (co)polymer is preferably alkali soluble.
  • the sulphonamide group is preferably represented by -NR-SO 2 -, -SO 2 -NR- or -SO 2 -NRR' wherein R and R' each independently represent hydrogen or an organic substituent.
  • Sulfonamide (co)polymers are preferably high molecular weight compounds prepared by homopolymerization of monomeric units containing at least one sulfonamide group or by copolymerization of such monomeric units and other polymerizable monomeric units.
  • Examples of monomeric units containing at least one sulfonamide group include monomeric units further containing at least one polymerizable unsaturated bond such as an acryloyl, allyl or vinyloxy group. Suitable examples are disclosed in U.S. 5,141,838 , EP 1545878 , EP 909,657 , EP 0 894 622 and EP 1,120,246 .
  • Examples of monomeric units copolymerized with the monomeric units containing at least one sulfonamide group include monomeric units as disclosed in EP 1,262,318 , EP 1,275,498 , EP 909,657 , EP 1,120,246 , EP 0 894 622 and EP 1,400,351 .
  • EP-A 933 682 Suitable examples of sulfonamide (co)polymers and/or their method of preparation are disclosed in EP-A 933 682 , EP-A 982 123 , EP-A 1 072 432 , WO 99/63407 and EP 1,400,351 .
  • a highly preferred example of a sulfonamide (co)polymer is a homopolymer or copolymer comprising a structural unit represented by the following general formula (I): wherein:
  • the structural unit represented by the general formula (I) has preferably the following groups:
  • sulphonamide (co)polymers are polymers comprising N-(p-aminosulfonylphenyl) (meth)acrylamide, N-(m-aminosulfonylphenyl) (meth)acrylamide and/or N-(o-aminosulfonylphenyl) (meth)acrylamide.
  • a particularly preferred sulphonamide (co)polymer is a polymer comprising N-(p-aminosulphonylphenyl) methacrylamide wherein the sulphonamide group comprises an optionally substituted straight, branched, cyclic or heterocyclic alkyl group, an optionally substituted aryl group or an optionally substituted heteroaryl group.
  • the layer comprising the sulphonamide (co)polymer may further comprise additional hydrophobic binders such as a phenolic resin (e.g. novolac, resoles or polyvinyl phenols), a chemically modified phenolic resin or a polymer containing a carboxyl group, a nitrile group or a maleimide group.
  • additional hydrophobic binders such as a phenolic resin (e.g. novolac, resoles or polyvinyl phenols), a chemically modified phenolic resin or a polymer containing a carboxyl group, a nitrile group or a maleimide group.
  • the dissolution behavior of the coating of the latter embodiment in the developer can be fine-tuned by optional solubility regulating components. More particularly, development accelerators and development inhibitors can be used. In the embodiment where the coating comprises more than one layer, these ingredients can be added to the first layer, to the second layer and/or to an optional other layer of the coating.
  • Development accelerators are compounds which act as dissolution promoters because they are capable of increasing the dissolution rate of the coating.
  • cyclic acid anhydrides, phenols or organic acids can be used in order to improve the aqueous developability.
  • the cyclic acid anhydride include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endoxy-4-tetrahydro-phthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, alpha -phenylmaleic anhydride, succinic anhydride, and pyromellitic anhydride, as described in U.S. Patent No.
  • Examples of the phenols include bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4'-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4',4"-trihydroxytriphenylmethane, and 4,4',3",4"-tetrahydroxy-3,5,3',5'-tetramethyltriphenyl-methane, and the like.
  • Examples of the organic acids include sulphonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphates, and carboxylic acids, as described in, for example, JP-A Nos. 60-88,942 and 2-96,755 .
  • organic acids include p-toluenesulphonic acid, dodecylbenzenesulphonic acid, p-toluenesulfinic acid, ethylsulfuric acid, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, 3,4,5-trimethoxybenzoic acid, 3,4,5-trimethoxycinnamic acid, phthalic acid, terephthalic acid, 4-cyclohexene-1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, and ascorbic acid.
  • the amount of the cyclic acid anhydride, phenol, or organic acid contained in the coating is preferably in the range of 0.05 to 20% by weight, relative to the coating as a whole.
  • Polymeric development accelerators such as phenolic-formaldehyde resins comprising at least 70 mol% meta-cresol as recurring monomeric units are also suitable development accelerators.
  • the coating also contains developer resistance means, also called development inhibitors, i.e. one or more ingredients which are capable of delaying the dissolution of the unexposed areas during processing.
  • developer resistance means also called development inhibitors
  • the dissolution inhibiting effect is preferably reversed by heating, so that the dissolution of the exposed areas is not substantially delayed and a large dissolution differential between exposed and unexposed areas can thereby be obtained.
  • the compounds described in e.g. EP-A 823 327 and WO97/39894 are believed to act as dissolution inhibitors due to interaction, e.g. by hydrogen bridge formation, with the alkali-soluble resin(s) in the coating.
  • Inhibitors of this type typically comprise at least one hydrogen bridge forming group such as nitrogen atoms, onium groups, carbonyl (-CO-), sulfinyl (-SO-) or sulfonyl (-SO 2 -) groups and a large hydrophobic moiety such as one or more aromatic rings.
  • hydrogen bridge forming group such as nitrogen atoms, onium groups, carbonyl (-CO-), sulfinyl (-SO-) or sulfonyl (-SO 2 -) groups and a large hydrophobic moiety such as one or more aromatic rings.
  • Suitable inhibitors improve the developer resistance because they delay the penetration of the aqueous alkaline developer into the coating.
  • Such compounds can be present in the first layer and/or, if present, in the second layer as described in e.g. EP-A 950 518 , and/or in a development barrier layer on top of said layer, as described in e.g. EP-A 864 420 , EP-A 950 517 , WO 99/21725 and WO 01/45958 .
  • the solubility of the barrier layer in the developer or the penetrability of the barrier layer by the developer can be increased by exposure to heat or infrared light.
  • inhibitors which delay the penetration of the aqueous alkaline developer into the coating include the following:
  • the above mentioned inhibitor of type (b) and (c) tends to position itself, due to its bifunctional structure, at the interface between the coating and air and thereby forms a separate top layer even when applied as an ingredient of the coating solution of the first and/or of the optional second layer.
  • the surfactants also act as a spreading agent which improves the coating quality.
  • the separate top layer thus formed seems to be capable of acting as the above mentioned barrier layer which delays the penetration of the developer into the coating.
  • the inhibitor of type (a) to (c) can be applied in a separate solution, coated on top of the first, optional second and/or other layers of the coating.
  • a solvent in the separate solution that is not capable of dissolving the ingredients present in the other layers so that a highly concentrated water-repellent or hydrophobic phase is obtained at the top of the coating which is capable of acting as the above mentioned development barrier layer.
  • first or optional second layer and/or other layer may comprise polymers that further improve the run length and/or the chemical resistance of the plate.
  • examples thereof are polymers comprising imido (-CO-NR-CO-) pendant groups, wherein R is hydrogen, optionally substituted alkyl or optionally substituted aryl, such as the polymers described in EP-A 894 622 , EP-A 901 902 , EP-A 933 682 and WO 99/63407 .
  • the coating of the heat-sensitive printing plate precursors described above preferably also contains an infrared light absorbing dye or pigment which, in the embodiment where the coating comprises more than one layer, may be present in the first layer, and/or in the second layer, and/or in an optional other layer.
  • Preferred IR absorbing dyes are cyanine dyes, merocyanine dyes, indoaniline dyes, oxonol dyes, pyrilium dyes and squarilium dyes. Examples of suitable IR dyes are described in e.g. EP-As 823327 , 978376 , 1029667 , 1053868 , 1093934 ; WO 97/39894 and 00/29214 .
  • Preferred compounds are the following cyanine dyes:
  • the concentration of the IR-dye in the coating is preferably between 0.25 and 15.0 %wt, more preferably between 0.5 and 10.0 %wt, most preferably between 1.0 and 7.5 %wt relative to the coating as a whole.
  • the coating may further comprise one or more colorant(s) such as dyes or pigments which provide a visible color to the coating and which remain in the coating at unexposed areas so that a visible image is obtained after exposure and processing.
  • dyes are often called contrast dyes or indicator dyes.
  • the dye has a blue color and an absorption maximum in the wavelength range between 600nm and 750 nm.
  • the dye absorbs visible light, it preferably does not sensitize the printing plate precursor, i.e. the coating does not become more soluble in the developer upon exposure to visible light.
  • contrast dyes are the amino-substituted tri- or diarylmethane dyes, e.g.
  • the contrast dye(s) may be present in the first layer, and/or in the optional second and/or other layers.
  • the heat-sensitive plate precursor can be image-wise exposed directly with heat, e.g. by means of a thermal head, or indirectly by infrared light, preferably near infrared light.
  • the infrared light is preferably converted into heat by an IR light absorbing compound as discussed above.
  • the heat-sensitive lithographic printing plate precursor is preferably not sensitive to visible light, i.e. no substantial effect on the dissolution rate of the coating in the developer is induced by exposure to visible light. Most preferably, the coating is not sensitive to ambient daylight.
  • the printing plate precursor can be exposed to infrared light by means of e.g. LEDs or a laser.
  • the light used for the exposure is a laser emitting near infrared light having a wavelength in the range from about 750 to about 1500 nm, more preferably 750 to 1100 nm, such as a semiconductor laser diode, a Nd:YAG or a Nd:YLF laser.
  • the required laser power depends on the sensitivity of the plate precursor, the pixel dwell time of the laser beam, which is determined by the spot diameter (typical value of modern plate-setters at 1/e 2 of maximum intensity : 5-25 ⁇ m), the scan speed and the resolution of the exposure apparatus (i.e. the number of addressable pixels per unit of linear distance, often expressed in dots per inch or dpi; typical value : 1000-4000 dpi).
  • ITD plate-setters for thermal plates are typically characterized by a very high scan speed up to 500 m/sec and may require a laser power of several Watts.
  • An XTD platesetter equipped with one or more laserdiodes emitting in the wavelength range between 750 and 850 nm is an especially preferred embodiment for the method of the present invention.
  • the known plate-setters can be used as an off-press exposure apparatus, which offers the benefit of reduced press down-time.
  • XTD plate-setter configurations can also be used for on-press exposure, offering the benefit of immediate registration in a multi-color press. More technical details of on-press exposure apparatuses are described in e.g. US 5,174,205 and US 5,163,368 .
  • the precursor can be developed by means of a suitable processing liquid, such as an aqueous alkaline solution, whereby the non-image areas of the coating are removed; the development step may be combined with mechanical rubbing, e.g. by using a rotating brush. During development, any water-soluble protective layer present is also removed.
  • a suitable processing liquid such as an aqueous alkaline solution
  • any water-soluble protective layer present is also removed.
  • the heat-sensitive printing plate precursors based on latex coalescence can also be developed using plain water or aqueous solutions, e.g. a gumming solution.
  • the gum solution is typically an aqueous liquid which comprises one or more surface protective compounds that are capable of protecting the lithographic image of a printing plate against contamination or damaging. Suitable examples of such compounds are film-forming hydrophilic polymers or surfactants.
  • the gum solution has preferably a pH from 4 to 10, more preferably from 5 to 8.
  • Preferred gum solutions are described in EP 1,342,568 .
  • printing plate precursors can after exposure directly be mounted on a printing press and be developed on-press by supplying ink and/or fountain to the precursor.
  • EP 1614538 More details concerning the development step can be found in for example EP 1614538 , EP 1614539 , EP 1614540 and WO/2004071767 .
  • UV-sensitive coatings can be used in the methods of the present invention.
  • Typical examples of such plates are the UV-sensitive "PS" plates and the so-called photopolymer plates which contain a photopolymerizable composition that hardens upon exposure to light.
  • a conventional, UV-sensitive "PS" plate is used. Suitable examples of such plates, that are sensitive in the range of 300-450 nm (near UV and blue light), have been discussed in EP 1,029,668 A2 . Positive and negative working compositions are typically used in "PS" plates.
  • the positive working imaging layer preferably comprises an o-naphtoquinonediazide compound (NQD) and an alkali soluble resin.
  • NQD o-naphtoquinonediazide compound
  • Particularly preferred are o-naphthoquinone-diazidosulphonic acid esters or o-naphthoquinone diazidocarboxylic acid esters of various hydroxyl compounds and o-naphthoquinone-diazidosulphonic acid amides or o-naphthoquinone-diazidocarboxylic acid amides of various aromatic amine compounds.
  • Two variants of NQD systems can be used: one-component systems and two-component systems.
  • Such light-sensitive printing plates have been widely disclosed in the prior art, for example in U.S. 3,635,709 , J.P. KOKAI No. 55-76346 , J.P. KOKAI No. Sho 50-117503 , J.P. KOKAI No. Sho 50-113305 , U.S. 3,859,099 ; U.S. 3,759,711 ; GB-A 739654 , US 4,266,001 and J.P. KOKAI No. 55-57841 .
  • the negative working layer of a "PS" plate preferably comprises a diazonium salt, a diazonium resin or an aryldiazosulfonate homo- or copolymer.
  • Suitable examples of low-molecular weight diazonium salts include: benzidine tetrazoniumchloride, 3,3'-dimethylbenzidine tetrazoniumchloride, 3,3'-dimethoxybenzidine tetrazoniumchloride, 4,4'-diaminodiphenylamine tetrazoniumchloride, 3,3'-diethylbenzidine tetrazoniumsulfate, 4-aminodiphenylamine diazoniumsulfate, 4-aminodiphenylamine diazoniumchloride, 4-piperidino aniline diazoniumsulfate, 4-diethylamino aniline diazoniumsulfate and oligomeric condensation products of diazodiphenylamine and formaldeh
  • diazo resins examples include condensation products of an aromatic diazonium salt as the light-sensitive substance. Such condensation products are described, for example, in DE-P-1 214 086 .
  • the light- or heat-sensitive layer preferably also contains a binder e.g. polyvinyl alcohol.
  • the diazo resins or diazonium salts Upon exposure the diazo resins or diazonium salts are converted from water soluble to water insoluble (due to the destruction of the diazonium groups) and additionally the photolysis products of the diazo may increase the level of crosslinking of the polymeric binder or diazo resin, thereby selectively converting the coating, in an image pattern, from water soluble to water insoluble.
  • the unexposed areas remain unchanged, i.e. water-soluble.
  • Such printing plate precursors can be developed using an aqueous alkaline solution as described above.
  • the light sensitive printing plate is based on a photo-polymerisation reaction and contains a coating comprising a photocurable composition comprising a free radical initiator (as disclosed in for example US 5,955,238 ; US 6,037,098 ; US 5,629,354 ; US 6,232,038 ; US 6,218,076 ; US 5,955,238 ; US 6,037,098 ; US 6, 010, 824 ; US 5,629,354 ; DE 1,470,154 ; EP 024,629 ; EP 107,792 ; US 4,410,621 ; EP 215,453 ; DE 3,211,312 and EP A 1,091,247 ) a polymerizable compound (as disclosed in EP1,161,4541 , EP 1349006 , W02005/109103 and unpublished European patent applications EP 5,111,012.0 , EP 5,111,025.2 , EP 5110918.9 and EP 5, 110,961.9 ) and
  • sensitizers such as sensitizers, co-initiators, adhesion promoting compounds, colorants, surfactants and/or printing out agents may optionally be added.
  • These printing plates can be sensitized with blue, green or red light (i.e. wavelength range between 450 and 750 nm), with violet light (i.e. wavelength range between 350 and 450 nm) or with infrared light (i.e. wavelength range between 750 and 1500 nm) using for example an Ar laser (488 nm) or a FD-YAG laser (532 nm), semiconductor lasers InGaN (350 to 450 nm), an infrared laser diode (830 nm) or a Nd-YAG laser (1060 nm).
  • blue, green or red light i.e. wavelength range between 450 and 750 nm
  • violet light i.e. wavelength range between 350 and 450 nm
  • infrared light i.e. wavelength range between 750 and 1500
  • a photopolymer plate is processed in alkaline developer having a pH > 10 (see above) and subsequently gummed.
  • the exposed photopolymer plate can also be developed by applying a gum solution to the coating whereby the non-exposed areas are removed. Suitable gumming solutions are described in WO/2005/111727 .
  • the imaged precursor can also be directly mounted on a press and processed on-press by applying ink and/or fountain solution.
  • the protective layer generally comprises at least one water-soluble binder, such as polyvinyl alcohol, polyvinylpyrrolidone, partially hydrolyzed polyvinyl acetates, gelatin, carbohydrates or hydroxyethylcellulose, and can be produced in any known manner such as from an aqueous solution or dispersion which may, if required, contain small amounts - i.e. less than 5% by weight based on the total weight of the coating solvents for the protective layer - of organic solvents.
  • the thickness of the protective layer can suitably be any amount, advantageously up to 5.0 ⁇ m, preferably from 0.1 to 3.0 ⁇ m, particularly preferably from 0.15 to 1.0 ⁇ m.
  • the coating may further contain additional ingredients such as surfactants, especially perfluoro surfactants, silicon or titanium dioxide particles or polymers particles such as matting agents and spacers.
  • surfactants especially perfluoro surfactants, silicon or titanium dioxide particles or polymers particles such as matting agents and spacers.
  • any coating method can be used for applying two or more coating solutions to the hydrophilic surface of the support.
  • the multi-layer coating can be applied by coating/drying each layer consecutively or by the simultaneous coating of several coating solutions at once.
  • the volatile solvents are removed from the coating until the coating is self-supporting and dry to the touch.
  • the residual solvent content may be regarded as an additional composition variable by means of which the composition may be optimized. Drying is typically carried out by blowing hot air onto the coating, typically at a temperature of at least 70°C, suitably 80-150°C and especially 90-140°C. Also infrared lamps can be used.
  • the drying time may typically be 15-600 seconds.
  • a heat treatment and subsequent cooling may provide additional benefits, as described in WO99/21715 , EP-A 1074386 , EP-A 1074889 , WO00/29214 , and WO/04030923 , WO/04030924 , WO/04030925 .
  • the printing plates thus obtained can be used for conventional, so-called wet offset printing, in which ink and an aqueous dampening liquid are supplied to the plate.
  • Another suitable printing method uses so-called single-fluid ink without a dampening liquid.
  • Suitable single-fluid inks have been described in US 4,045,232 ; US 4,981,517 and US 6,140,392 .
  • the single-fluid ink comprises an ink phase, also called the hydrophobic or oleophilic phase, and a polyol phase as described in WO 00/32705 .
  • thermo-resist for forming a pattern on a substrate by direct imaging techniques, e.g. in a PCB (printed circuit board) application as described in US 2003/0003406 A1 .
  • a 0.3mm thick AA1050 aluminium sheet was first degreased in NaOH (25 g/1) at 70°C for 10 seconds and washed in deionised water at room temperature for 5 seconds. Afterwards the sheet was neutralised in a diluted HCl solution with a pH ⁇ 2 at room temperature for 10 seconds and washed again in deionised water at room temperature for 5 seconds. Finally the aluminum sheet was potentiostatically (constant voltage) grained at 37°C using a charge density of 720 C/dm 2 and a current density of 120 A/dm 2 . The graining process was carried out in 12.5 g/l HCl solution. The obtained substrate is the comparative lithographic support PPS-0.
  • the invention lithographic supports PPS-1 to PPS-10 were obtained by adding the additives summarized in Table 1 at two different concentrations (0.0034 M, and 0.034 M).
  • Table 1 invention printing plate supports.
  • Printing plate support (PPS) Extra additive Concentration M PPS-1a Benzoic acid 0.0034 PPS-1b Benzoic acid 0.034 PPS-2a 3-aminobenzoic acid 0.0034 PPS-2b 3-aminobenzoic acid 0.034 PPS-3a 4-aminobenzoic acid 0.0034 PPS-3b 4-aminobenzoic acid 0.034 PPS-4a 3-amino-4-hydroxybenzoic acid 0.0034 PPS-4b 3-amino-4-hydroxybenzoic acid 0.034 PPS-5a 4-sulfobenzoic acid 0.0034 PPS-5b 4-sulfobenzoic acid 0.034 PPS-6a Benzene-sulphonic acid 0.0034 PPS-6b Benzene-sulphonic acid 0.034 PPS-7a An
  • a 0.3mm thick AA1050 aluminium was first degreased in NaOH (25 g/l) at 70°C for 10 seconds and washed in deionised water at room temperature for 5 seconds. Afterwards it was neutralised in a diluted HCl solution (pH ⁇ 2) at room temperature for 10 seconds and washed again in deionised water at room temperature for 5 seconds. Finally it was potentiostatically (constant voltage) grained at 37°C using 960 C/dm 2 and 120 A/dm 2 as charge and current density, respectively. The graining process was carried out in 12.5 g/l HCl solution. The obtained substrate is the comparative lithographic support PPS-11.
  • the invention lithographic supports PPS-12 to PPS-21 were obtained by adding to the graining solution containing 12.5 g/l HCl the additives summarized in Table 1 at three different concentrations (0.00034M, 0.0034M, and 0.034M).
  • Table 3 invention printing plate supports PPS 12 - PPS 21.
  • a 0.3mm thick AA1050 aluminium was first degreased in NaOH (25g/l) at 70°C for 10 seconds and washed in deionised water at RT for 5 seconds. Afterwards it was neutralised in a diluted HCl solution (pH ⁇ 2) at room temperature for 10 seconds and washed again in deionised water at RT for 5 seconds. Finally it was galvanostatically (constant current) grained at 37°C using 960C/dm2 and 120A/dm2 as charge and current density, respectively. The graining process was carried out in 12.5 g/l HCl solution. The obtained substrate is the comparative lithographic support PPS-22.
  • invention lithographic supports PPS-23 to PPS-26 are obtained by adding to the graining solution containing 12.5 g/l HCl the additives summarized in Table 5 at a concentration of 0.034M.
  • Table 5 invention printing plate supports PPS 23 - PPS 26.

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Claims (13)

  1. Un procédé pour la production d'un support d'une plaque d'impression lithographique, comprenant les étapes ci-après :
    (i) la mise à disposition d'un support aluminium,
    (ii) le grainage du support dans une composition d'électrolyte de grainage et
    (iii) l'anodisation du support grainé,
    caractérisé en ce que la composition d'électrolyte contient un dérivé d'acide benzoïque ou un dérivé d'acide sulfonique dans un rapport efficace.
  2. Procédé selon la revendication 1, caractérisé en ce que le rapport efficace du dérivé d'acide benzoïque ou du dérivé d'acide sulfonique se situe entre 0,0001 moles/l et 0,2 moles/l.
  3. Procédé selon la revendication 1, caractérisé en ce que le rapport efficace du dérivé d'acide benzoïque ou du dérivé d'acide sulfonique se situe entre 0,001 moles/l et 0,05 moles/l.
  4. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que le dérivé d'acide benzoïque est choisi parmi la liste composée d'acide benzoïque éventuellement substitué, d'acide phtalique éventuellement substitué, d'acide isophtalique éventuellement substitué, d'acide téréphtalique éventuellement substitué, d'acide salicylique éventuellement substitué, d'anhydride benzoïque éventuellement substitué, d'acide 1-naphtoïque éventuellement substitué, d'acide 2-naphtoïque éventuellement substitué ou de sels ou esters de ceux-ci.
  5. Procédé selon les revendications 1, 2 ou 3, caractérisé en ce que le dérivé d'acide sulfonique est choisi parmi la liste composée d'acide benzène-sulfonique éventuellement substitué, d'acide benzène-disulfonique éventuellement substitué, d'acide pyridine-sulfonique éventuellement substitué, d'acide naphtalène-sulfonique éventuellement substitué, d'acide naphtalène-disulfonique éventuellement substitué, d'acide alkyle-sulfonique éventuellement substitué, d'acide alkylène-sulfonique éventuellement substitué, d'acide quinoline-sulfonique éventuellement substitué ou de sels ou esters de ceux-ci.
  6. Un procédé pour la production d'un précurseur de plaque d'impression lithographique, comprenant les étapes ci-après :
    (i) la mise à disposition d'un support selon le procédé selon l'une quelconque des revendications précédentes,
    (ii) l'application sur le support d'un revêtement contenant au moins une couche formatrice d'image thermosensible ou photosensible et
    (iii) le séchage du précurseur ainsi obtenu.
  7. Procédé selon la revendication 6, caractérisé en ce que le revêtement contient un agent absorbant les rayons infrarouges et deux couches formatrices d'image thermosensibles, à savoir :
    (i) une première couche contenant une résine oléophile thermosensible
    (ii) et une deuxième couche appliquée entre la première couche et le support hydrophile et contenant un polymère comprenant au moins une unité monomère contenant au moins un groupe sulfonamide.
  8. Procédé selon la revendication 7, caractérisé en ce que l'unité monomère contenant au moins un groupe sulfonamide répond à la formule (I) suivante :
    Figure imgb0006
     où :
    R1 représente un atome d'hydrogène ou un groupe hydrocarbure contenant jusqu'à 12 atomes de carbone,
    R2 et R3 représentent, indépendamment l'un de l'autre, un atome d'hydrogène ou un groupe hydrocarbure,
    X1 représente une liaison simple ou un groupe de liaison bivalent,
    Y1 représente un groupe sulfonamide bivalent répondant à la formule -NRj-SO2- ou à la formule SO2-NRk-, où Rj et Rk représentent, indépendamment l'un de l'autre, un atome d'hydrogène, un groupe alkyle éventuellement substitué, un groupe alkanoyle éventuellement substitué, un groupe alkényle éventuellement substitué, un groupe alkynyle éventuellement substitué, un groupe cycloalkyle éventuellement substitué, un groupe hétérocyclique éventuellement substitué, un groupe aryle éventuellement substitué, un groupe hétéroaryle éventuellement substitué, un groupe aralkyle éventuellement substitué ou un groupe hétéroalkyle éventuellement substitué, ou un groupe répondant à la formule -C(=N)-NH-R2, où R2 représente un atome d'hydrogène, un groupe alkyle éventuellement substitué ou un groupe aryle éventuellement substitué, et
    Z1 représente un groupe terminal ou un groupe de liaison bivalent, trivalent ou tétravalent dans lequel les 1 à 3 liaisons résiduelles de Z1 sont liées à Y1.
  9. Procédé selon les revendications 7 ou 8, caractérisé en ce que le revêtement comprend en outre une couche d'arrêt de développement appliquée sur la première couche et la deuxième couche et contenant un composé choisi parmi le groupe suivant :
    - un polymère ou copolymère hydrophobe,
    - un composé bifonctionnel contenant un groupe polaire et un groupe hydrophobe ou
    - un copolymère séquencé bifonctionnel contenant un bloc polaire et un bloc hydrophobe.
  10. Procédé selon la revendication 9, caractérisé en ce que le copolymère séquencé bifonctionnel contient un bloc d'un oxyde de polyalkylène ou un bloc d'un oxyde d'oligoalkylène et un bloc hydrophobe, tel qu'un groupe hydrocarbure à longue chaîne, un groupe polysiloxane ou un groupe oligosiloxane et/ou un groupe hydrocarbure perfluoré.
  11. Procédé selon la revendication 10, caractérisé en ce que la quantité du copolymère séquencé bifonctionnel varie entre 0,5 et 25 mg/m2 par rapport au grammage de la couche.
  12. Procédé selon la revendication 6, caractérisé en ce que la couche formatrice d'image thermosensible contient un agent absorbant les rayons infrarouges, des particules d'un polymère hydrophobe thermoplastique et un liant hydrophile.
  13. Un procédé pour la production d'une plaque d'impression lithographique, comprenant les étapes ci-après :
    (i) la mise à disposition d'un précurseur d'une plaque d'impression tel que défini dans le procédé selon les revendications 6 à 12,
    (ii) l'exposition du précurseur d'une plaque d'impression à de la chaleur et/ou à de la lumière et
    (iii) le cas échéant, le développement du précurseur exposé en utilisant un liquide aqueux.
EP06110469A 2006-02-28 2006-02-28 Procédé pour la production d'un support pour plaque d'impression lithographique Expired - Fee Related EP1826022B1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
EP06110469A EP1826022B1 (fr) 2006-02-28 2006-02-28 Procédé pour la production d'un support pour plaque d'impression lithographique
DE602006003856T DE602006003856D1 (de) 2006-02-28 2006-02-28 Verfahren zur Herstellung eines lithographischen Druckplattenträgers
PCT/EP2007/051274 WO2007099024A1 (fr) 2006-02-28 2007-02-09 Procede permettant de fabriquer un support de plaque d'impression lithographique
US12/280,261 US20090084683A1 (en) 2006-02-28 2007-02-09 Method for making a lithographic printing plate support
CN200780006955.6A CN101389488B (zh) 2006-02-28 2007-02-09 制作平版印刷印版载体及印版前体的方法

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP06110469A EP1826022B1 (fr) 2006-02-28 2006-02-28 Procédé pour la production d'un support pour plaque d'impression lithographique

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EP1826022B1 true EP1826022B1 (fr) 2008-11-26

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DE602006004839D1 (de) * 2006-02-28 2009-03-05 Agfa Graphics Nv Positiv arbeitende Lithografiedruckformen
DE602006009919D1 (de) 2006-08-03 2009-12-03 Agfa Graphics Nv Flachdruckplattenträger
US8793873B2 (en) * 2010-06-07 2014-08-05 Memjet Technology Ltd. Method of providing printhead assembly having complementary hydrophilic and hydrophobic surfaces
EP2489512B1 (fr) * 2011-02-18 2013-08-28 Agfa Graphics N.V. Précurseur de plaque d'impression lithographique
CN102841502B (zh) * 2012-09-21 2014-06-04 成都星科印刷器材有限公司 一种热敏ctp版材用成像液
EP2871057B1 (fr) 2013-11-07 2016-09-14 Agfa Graphics Nv Précurseur de plaque d'impression lithographique thermosensible à action négative
EP3157310A1 (fr) 2015-10-12 2017-04-19 Agfa Graphics Nv Feuille d'entrée de perforation de cartes électriques telles que des cartes de circuit imprimé
CN117187746A (zh) * 2017-11-14 2023-12-08 大日本印刷株式会社 金属板的制造方法和蒸镀掩模的制造方法

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WO2007099024A1 (fr) 2007-09-07
CN101389488B (zh) 2011-04-13
US20090084683A1 (en) 2009-04-02
DE602006003856D1 (de) 2009-01-08
EP1826022A1 (fr) 2007-08-29
CN101389488A (zh) 2009-03-18

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