Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C1/00—Forme preparation
  • B41C1/10—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
  • 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
  • B41C2210/06—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
  • B41C2210/14—Multiple imaging layers
• • 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
  • B41C2210/20—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation characterised by inorganic additives, e.g. pigments, salts
• • 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

Definitions

• the invention relates to a recording material with a substrate and a radiation-sensitive layer that absorbs IR radiation Component contains and after exposure to infrared radiation in one aqueous-alkaline developer becomes soluble or at least swellable.
• the Material is insensitive to white light. It is particularly suitable for Manufacture of printing forms for offset printing.
• the radiation-sensitive layer in the ultraviolet and / or visible range is sensitive.
• the layer with radiation of the corresponding wavelength passes through it illustrated and then developed. Newer procedures come without such a film template.
• infrared lasers especially infrared laser diodes
• recording materials are needed, which in IR range, i.e. in the range from about 700 to 1,100 nm.
• the present invention thus relates to a recording material with a substrate and a radiation-sensitive, water-insoluble Layer containing an IR radiation absorbing component and after Exposure to infrared radiation soluble in an aqueous alkaline developer or at least becomes swellable.
• the recording material is characterized in that that there is a cover layer on the radiation-sensitive layer located that is opaque to white light, but to radiation in the IR range is permeable and can be removed with water or an aqueous solution.
• the cover layer also makes the scratch-sensitive of the radiation-sensitive Layer greatly reduced.
• the Top layer that are components of the radiation-sensitive layer, the possibly detached under the influence of the IR laser beams in the Remove the radiation device. Especially for inner drum imagesetters Contamination of the laser optics can lead to problems.
• "White Light” means daylight or light from incandescent lamps, fluorescent tubes and others Illuminants that emit ordinary white light. Under “Radiation in the IR range” is intended here - as is generally the case - radiation with a Wavelength of 700 to 1,100 nm can be understood.
• the top layer generally contains at least one water-soluble, organic, polymeric binder and at least one component, the radiation absorbed in the UV / VIS range.
• This component preferably has one Absorption maximum in the range from 300 to 500 nm, especially in the range of 350 to 450 nm.
• UV / VIS absorbers can also be used, but must first be dispersed with a water-soluble binder. That to disperse
• the binder used is preferably identical to the rest Binder in the top layer.
• the proportion of UV / VIS absorber is generally 5 to 50 wt .-%, preferably 20 to 30 wt .-%, each based on the total weight of the non-volatile components of the top layer.
• the optical density of the cover layer is preferably 2.2 to 2.5.
• suitable binders for the top layer are polyvinyl alcohols, polyvinyl pyrrolidones, partially saponified polyvinyl acetates, which also contain vinyl ether or may contain vinyl acetal units, gelatin, carbohydrates, Cellulose derivatives (e.g. hydroxyethyl cellulose), gum arabic, polyethylene oxides, Polyvinyl ether, poly (meth) acrylates and corresponding mixed polymers. Polyvinyl alcohols are particularly preferred.
• the top layer still minor amounts of surfactants, surfactants, inert Contain particles and / or plasticizers.
• the thickness of the top layer is generally up to 5 ⁇ m, preferably 0.5 to 2.5 ⁇ m. It should be chosen so that the IR-sensitive layer underneath can still be imaged without problems.
• a top layer was also known from EP-A 0 354 475, which protects the underlying photopolymerizable layer from oxygen and at the same time acts as an optical filter. It contains a dye that Absorbs light with a wavelength of 300 to 700 nm, but within this area has an absorption gap. The gap is chosen that they are the emission range of the light source used for imaging equivalent.
• the well-known top layer is then together with the non-irradiated areas of the photopolymerizable layer through the Developer solution removed.
• the composition of the IR-sensitive layer is not particularly critical. However, it must be insoluble in water at least to the extent that it is removed the top layer is practically not attacked.
• Carbon black pigments such as those described in WO 96/20429, are particularly suitable as IR-absorbing components, because they absorb over a wide IR wavelength range. When used, therefore, both Nd-YAG lasers, which operate at a wavelength of 1064 nm, and inexpensive laser diodes, which operate at 830 nm, can be used. Carbon black pigments with an average primary particle diameter of less than 80 nm are preferred. According to DIN 53206, the term “primary particles” refers to the smallest particles (individual particles) from which pulverulent substances are built up. They are recognizable as individual individuals by electron microscopy. Suitable carbon blacks are flame, furnace or channel blacks.
• the surface determined by the method of Brunauer, Emmett and Teller is generally more than 10 m 2 / g.
• Particularly suitable carbon blacks are oxidized on their surface, which creates acidic units.
• the soot particles can be dispersed with a binder in generally known devices.
• the mixture of pigment and binder can be predispersed in a dissolver and then finely dispersed in a ball mill.
• the organic solvents used can differ from the actual coating solvents, but they are preferably identical.
• Particularly suitable solvents are propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), ethyl lactate, butanone, ⁇ -butyrolactone, tetrahydrofuran and mixtures thereof.
• PGME propylene glycol monomethyl ether
• PMEA propylene glycol monomethyl ether acetate
• ethyl lactate butanone
• ⁇ -butyrolactone tetrahydrofuran and mixtures thereof.
• surfactants and thickeners which are soluble in aqueous alkaline solutions are particularly preferred.
• other heat-absorbing substances such as squarylium, cyanine, merocyanine or pyrylium compounds, can also be present in the layer sensitive to IR radiation.
• the proportion of the IR-absorbing component is generally 0.5 to 30% by weight, preferably 2 to 15% by weight, in each case based on the total weight of the nonvolatile constituents of the
• the IR radiation-sensitive layer also contains a polymeric binder.
• binders having acidic groups whose pK a value is less than. 13 include, for example, polycondensates as obtained from the reaction of phenols or sulfamoyl- or carbamoyl-substituted aromatics with aldehydes or ketones.
• phenols can also be substituted phenols, such as resorcinol, cresol, xylenol or trimethylphenol, in addition to phenol.
• the aldehyde is preferably formaldehyde. Reaction products of diisocyanates with diols or diamines are also suitable as long as they have acidic units of the type mentioned.
• polymers with units of vinyl aromatics, N-aryl- (meth) acrylamides or aryl- (meth) acrylates these units each also having one or more carboxyl groups, phenolic hydroxyl groups, sulfamoyl or carbamoyl groups.
• the polymers can additionally contain units from other monomers which have no acidic groups.
• (meth) acrylate stands for "acrylate and / or methacrylate”.
• the proportion of the binder is generally 2 to 98% by weight, preferably 50 to 85% by weight, in each case based on the total weight of the nonvolatile constituents of the layer.
• the UVNIS-sensitive component is preferably an onium salt.
• a combination of an acid-forming compound and a compound which can be cleaved by the acid thermally or photochemically generated from this compound is also particularly suitable.
• Preferred acid-cleavable compounds are polymers with hydrophilic, acidic groups (especially carboxy and phenolic hydroxyl groups), some or all of which are masked with hydrophobic, acid-labile groups. After the acid-catalyzed elimination of the hydrophobic groups, the solubility of the polymer in aqueous alkaline developers is again greatly increased.
• the hydrophobic, acid-labile groups are, for example, tert -alkoxycarbonyloxy, benzyloxycarbonyloxy and alkoxyalkyl ester groups of the formula -CO-O-CR 1 R 2 -OR 3 , in which R 3 is a (C 1 -C 18 ) alkyl group and R 1 and R 2 independently of one another represent a hydrogen atom or a (C 1 -C 18 ) alkyl group with the proviso that at least one of the radicals R 1 and R 2 is a hydrogen atom.
• R 3 is a (C 1 -C 18 ) alkyl group
• R 1 and R 2 independently of one another represent a hydrogen atom or a (C 1 -C 18 ) alkyl group with the proviso that at least one of the radicals R 1 and R 2 is a hydrogen atom.
• Tert -butoxycarbonyloxy and tetrahydropyranyloxycarbonyl groups are particularly preferred.
• acid-cleavable groups such as tert -butoxycarbonyloxy groups.
• acid-labile groups gaseous decomposition products can be formed when they are split off.
• acid generators are diazonium, phosphonium, sulfonium and iodonium salts of strong acids. The counter ion in these salts is preferably hexafluorophosphate, hexafluoroantimonate or perfluoroalkanesulfonate.
• Diazo compounds especially esters or amides of 1,2-naphthoquinone-2-diazide-4- or -5-sulfonic acid. These include in particular esters of 1,2-naphthoquinone-2-diazid-4- or -5-sulfonic acid and a compound with at least one, preferably at least three phenolic hydroxyl groups.
• Hydroxyl groups such as 2,3,4-trihydroxy-benzophenone, 2,3,4-trihydroxy-3'methyl-, propyl or isopropyl benzophenone, 2,3,4,4'-tetrahydroxy benzophenone, 2,3,4,2 ', 4'-pentahydroxy-benzophenone, 2,3,4,2', 3 ', 4'-hexahydroxybenzophenone and 5,5'-diacyl-2,3,4,2 ', 3', 4'-hexahydroxy-diphenylmethane.
• Hydroxyl groups such as 2,3,4-trihydroxy-benzophenone, 2,3,4-trihydroxy-3'methyl-, propyl or isopropyl benzophenone, 2,3,4,4'-tetrahydroxy benzophenone, 2,3,4,2 ', 4'-pentahydroxy-benzophenone, 2,3,4,2', 3 ', 4'-hexahydroxybenzophenone and 5,5'-diacyl-2,3,4,2 ', 3
• Hydroxy components that can be used for the esterification are also condensation products from pyrogallol and aldehydes or ketones as well as condensation products from alkylated phenols and formaldehyde.
• the layer can also contain a mixture of several radiation-sensitive components.
• the proportion of the UVNIS-sensitive component is generally 1 to 50% by weight, preferably 5 to 30% by weight, in each case based on the total weight of the non-volatile components of the layer.
• the radiation-sensitive layer can also have further, in such layers contain common additives in minor amounts.
• common additives include indicator dyes (e.g. dialkylaminoazobenzenes), photochemical acid generators (e.g. trifluoromethanesulfonates or hexafluorophosphates of diazodiphenylamines), surfactants (preferred fluorine-containing surfactants or silicone surfactants), polyalkylene oxides for control the acidity of the acidic groups and / or low molecular weight compounds with acidic units to increase the development speed.
• indicator dyes e.g. dialkylaminoazobenzenes
• photochemical acid generators e.g. trifluoromethanesulfonates or hexafluorophosphates of diazodiphenylamines
• surfactants preferred fluorine-containing surfactants or silicone surfactants
• polyalkylene oxides for control the acidity of the acidic groups and / or low molecular weight
• the support in the recording material according to the invention is preferably an aluminum foil or plate.
• a composite of is also suitable an aluminum and a polyester film.
• the aluminum surface is preferred mechanically and / or electrochemically roughened and anodically oxidized.
• You can also with a suitable, usually polymeric Compound, be hydrophilized. Connections are well suited for this purpose with phosphonic acid or phosphonate units, especially polyvinylphosphonic acid.
• the actual roughening can be degreased, optionally also a further mechanical and / or chemical roughening be upstream.
• Suitable coating solvents are the above-mentioned, generally customary organic solvents, as can also be used in the dispersion of the carbon black.
• the IR radiation-sensitive layer generally has a layer weight of 0.5 to 5.0 g / m 2 , preferably 1.0 to 3.0 g / m 2 , corresponding to about 0.5 to 5.0 ⁇ m, preferred about 1.0 to 3.0 ⁇ m.
• the top layer is then applied from an aqueous solution or dispersion, which may also contain small amounts of organic solvents, ie less than 5% by weight, based on the total weight of the coating solvents for the top layer.
• the present invention finally also relates to a method for producing a printing form for offset printing from the recording material according to the invention.
• the recording material is first irradiated imagewise with infrared radiation and then developed in a conventional aqueous alkaline developer at a temperature of 20 to 40 ° C.
• the water-soluble top layer is also removed during development.
• the cover layer is removed with water before or after imaging with IR rays, but before development.
• External or inner drum imagesetters with laser diodes (emission maximum 830 nm) or Nd-YAG lasers (emission maximum 1064 nm) are particularly suitable for imaging with infrared rays.
• the developer generally has a ratio of SiO 2 to alkali oxide of at least 1. This ensures that the aluminum oxide layer of the carrier is not damaged.
• Preferred alkali oxides are Na 2 O and K 2 O, and mixtures thereof.
• the developer can contain further components, such as buffer substances, complexing agents, defoamers, organic solvents in small amounts, corrosion inhibitors, dyes, surfactants and / or hydrotropes. The development mostly takes place in machine processing plants.
• UV / VIS and IR sensitized recording material UV sensitization with diazo compound
• a coating dispersion was made from 20.0 pbw an ester of 1 mol of 2,3,4-trihydroxy-benzophenone and 1.5 mol of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride, 20.0 pbw Carbon black dispersion of the composition given below, 3.0 pbw 2,4-dihydroxy-benzophenone, 57.0 pbw Cresol / xylenol / formaldehyde novolak (®Alnovol SPN 400, 43.5% in propylene glycol monomethyl ether acetate), 455.0 pbw Propylene glycol monomethyl ether (PGME) and 455.0 pbw Tetrahydrofuran.
• PGME Propylene glycol monomethyl ether
• the soot dispersion consisted of 10.0 pbw Carbon black (®Printex 25), 10.0 pbw Cresol / xylenol / formaldehyde novolak (®Alnovol SPN 400, 45.3% in PGMEA), 28.8 pbw PGME and 0.01 pbw Silicone oil.
• the coating solution was roughened into a hydrochloric acid solution Anodized sulfuric acid and hydrophilized with polyvinylphosphonic acid Aluminum foil applied. After drying at 100 ° C. for 2 minutes, the Layer thickness 2 ⁇ m.
• the development was the same for both imagewise irradiated recording materials. It was carried out in a conventional processing plant at a throughput speed of 0.4 m / min at a temperature of 28 ° C. using an aqueous potassium silicate developer, the K 2 SiO 3 (normality: 0.8 mol / l in water) and 0.2% by weight .-% O, O'-bis-carboxymethyl-polyethylene glycol-1000 and 0.4 wt .-% pelargonic acid contained. A point resolution of 2 to 98% of a 60s grid was achieved with both recording materials. The background of the picture was free of fog. With the offset printing plates produced in this way, more than 100,000 flawless prints could be produced.
• Samples of the recording material were used to determine the daylight sensitivity before or after thermal imaging, but in any case before development, exposed to (UV-containing) daylight for different lengths of time. With a photometer (spectral sensitivity: 300 to 450 nm) the energy was determined which acted on the material. It was cheating about 2 mJ per square centimeter per minute. If only the material 1 min in daylight was already evident after the development Losses in the peak area, after 4 minutes in daylight the material had no more resistance and was also in the unirradiated areas of Developers attacked.
• UVNIS and IR-sensitized recording material UV sensitization by combining acid generator and polymer with acid-cleavable groups
• a plate made of electrochemically roughened and then anodized aluminum was coated with a dispersion by spin coating 6.7 pbw Poly (4-hydroxy-styrene) in which 30% of the hydroxyl groups were converted into tert-butoxycarbonyloxy groups and 15% into 2,3-dihydroxy-propoxy groups (as described in the unpublished DE 197 29 067.1), 0.5 pbw 4- para- toluenmercapto-2,5-diethoxy-benzenediazonium hexafluorophosphate, 0.01 pbw Silicone oil as a surface improver, 17.0 Gt Carbon black dispersion (as in example 1), 42.0 pbw Propylene glycol monomethyl ether and 34.0 pbw Tetrahydrofuran.
• the layer weight was 1.8 to 2.2 g / m 2 .
• the recording material thus produced was thermally imaged with an Nd-YAG laser (wavelength 1064 nm; power: 10 mW). In the irradiated areas, parts of the layer were detached by the gas evolution, which led to contamination of the irradiation device. The material was then developed in a developer at 28 ° C. for 1 min 5.5 pbw Sodium silicate nonahydrate, 3.4 pbw Trisodium phosphate dodecahydrate, 0.4 pbw Monosodium phosphate (anhydrous) and 90.7 pbw demineralized water.
• the top layers thus obtained were each applied to the recording material from Example 1 and dried at 100 ° C. for 2 minutes. The weight of the dried cover layer was then about 2 to 3 g / m 2 . The material thus obtained was then - as described in Example 1 a) - imaged with IR rays. The subsequent development was also carried out according to Example 1.
• the printing plates obtained in this way were equivalent to those from Example 1 in all their essential properties, particularly in terms of quality and durability.
• Example 1 b To carry out a conventional exposure - as described in Example 1 b) To be able to, the top layer was previously with ordinary tap water washed. The printing plates obtained after development showed practically no difference from those from Example 1 b).
• a coating solution according to Example 3c or 3f was applied to the recording material according to Example 2 and dried. After drying for 2 minutes at 100 ° C., the weight of the outer layers thus produced was again 2 to 3 g / m 2 . In contrast to comparative example 2, no constituents detached from the layer during IR irradiation.
• Example 1 without top layer
• Example 3c with top layer
• the size of the test disk was measured must be acting force so that after the development visible scratches in the image layer are recognizable.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Thermal Sciences (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Photosensitive Polymer And Photoresist Processing (AREA)
• Printing Plates And Materials Therefor (AREA)

Applications Claiming Priority (2)

Publications (3)

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• 1997
  • 1997-09-08 DE DE19739299A patent/DE19739299A1/de not_active Withdrawn
• 1998
  • 1998-09-02 EP EP98116561A patent/EP0900652B1/de not_active Expired - Lifetime
  • 1998-09-02 DE DE59804861T patent/DE59804861D1/de not_active Expired - Fee Related
  • 1998-09-08 JP JP10254363A patent/JPH11149162A/ja not_active Withdrawn
  • 1998-09-08 US US09/149,044 patent/US6165685A/en not_active Expired - Fee Related

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