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
• • 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]
  • Y10T428/31678—Of metal
  • Y10T428/31692—Next to addition polymer from unsaturated monomers

Definitions

• the invention relates to a mechanically and / or electrochemically roughened and optionally anodically oxidized carrier material made of aluminum or its alloys with a hydrophilic layer of at least one polymer with basic and acidic groups and a radiation-sensitive recording material with a carrier and a radiation-sensitive layer from which offset printing plates are produced can.
• Carrier materials for offset printing plates are provided with a light-sensitive layer (copying layer), with the help of which a printing image is generated by photomechanical means. After the printing image has been produced, the support carries the printing image areas and at the same time forms the hydrophilic image background for the lithographic printing process in the non-image areas (non-image areas).
• the carrier material is additionally hydrophilized, because otherwise it would not accept enough water.
• the hydrophilizing agent must be sensitive to the particular light Layer should be coordinated to avoid undesirable reactions and not to impair the adhesion.
• the known hydrophilization methods have more or less major disadvantages.
• the photosensitive layers After treatment with alkali silicates, which lead to good developability and hydrophilicity, the photosensitive layers must deteriorate after a long period of storage.
• carrier materials with water-soluble polymers, their good solubility - especially in aqueous-alkaline developers, as they are mainly used to develop positive-working layers - leads to a marked weakening of the hydrophilizing effect.
• Highly light-sensitive layers which are used for imaging with lasers (EP-A 0 364 735) and which are a polymer binder, a free-radically polymerizable compound with at least one polymerizable group and a photo-reducible dye, a trihalomethyl compound which can be cleaved by radiation and are particularly susceptible to the formation of color fog a metallocene compound included as photoinitiators. There are therefore particularly high demands on the hydrophilic carrier material, so that no constituents of the layer remain at the non-image areas.
• the carrier material is coated with a homopolymer of acrylamidoisobutylenephosphonic acid or a copolymer of acrylamidoisobutylenephosphonic acid and acrylamide or with a salt of this homo- or copolymer with an at least divalent metal cation.
• the coating has the advantage that the finished printing plates show good hydrophilicity at the non-image areas and have a reduced color haze.
• EP-A 0 490 231 describes the treatment of printing plate supports with polyethyleneimines which contain structural elements of the type - (CH2-CH2-N (X) -) n - or with polyvinylamines, the structural elements of Type - (CH2-CH (NY1Y2) -) n - contain, where X, Y1 and Y2 are optionally C-substituted sulfomethyl groups or phosphonomethyl groups. But even with this method, optimal results are not yet achieved.
• the object is achieved by a mechanically and / or electrochemically roughened and optionally anodically oxidized support material made of aluminum or its alloys with a hydrophilic layer of at least one polymer with basic and acidic groups, characterized in that the layer is followed by a further hydrophilic layer which contains at least one compound with at least one phosphono group.
• the basic groups in the polymer of the first hydrophilic layer are preferably primary, secondary or tertiary amino groups, the acidic groups are preferably carboxy, phosphono or sulfo groups.
• the secondary and tertiary amino groups can also be part of the main polymer chain.
• the sulfomethylated or phosphonomethylated polyethyleneimines and polyvinylamines described in EP-A 0 490 231 are particularly preferred for this first hydrophilic layer.
• These polymers can also contain units from other monomers contain, for example units from substituted amino acrylates, vinyl pyrrolidones or vinyl imidazoles. Polymers with units of dialkylaminoalkyl (meth) acrylate and (meth) acrylic acid are also particularly preferred.
• the polymers in the first layer are neither strongly acidic nor strongly alkaline. Their pH is approximately in the range from 4 to 9, preferably 4.5 to 7.5.
• the compounds with at least one phosphono group used for the further hydrophilic layer are clearly acidic. They generally have a pH of less than 4, preferably 1 to 3, in aqueous solution. These compounds are also preferably polymeric, the polyvinylphosphonic acid described in US Pat. No. 4,153,461 being particularly suitable.
• the sequence of the hydrophilizing layers is surprisingly of crucial importance for the quality of the product. There is no proven explanation for this, but there are hypothetical ideas. It is believed that the layer of at least one polymer with acidic and basic groups creates adsorption sites to which the connection with at least one phosphono group then attaches to a greater extent than would be the case without this activation. This is plausible insofar as various surface-sensitive methods such as energy dispersive X-ray (EDX), Auger electron spectroscopy, electron spectroscopy for chemical analysis (ESCA) and secondary ion mass spectroscopy (SIMS) can be used to demonstrate that only with this order of the layers, a particularly large amount of the active ingredients is drawn onto the surface of the carrier.
• the Hydrophilic layers can be continuous or discontinuous.
• part of the present invention is also a method for producing the carrier materials.
• the two hydrophilizing layers can be applied by spraying on the corresponding solutions or by immersing them in such solutions.
• the concentration of the hydrophilizing compounds in these solutions can vary within wide limits. However, solutions with a concentration of 0.1 to 50 g / l, preferably 0.3 to 5 g / l, have proven to be particularly advantageous.
• the material can be rinsed off to remove the unnecessary hydrophilizing agent. Drying between the two stages is not necessary, but it also does no harm. Coating can be done at temperatures from 20 to 95 ° C, but temperatures from 30 to 65 ° C are preferred.
• the material to be coated is generally sprayed or immersed for 1 s to 5 min. It is disadvantageous if the treatment time is shorter than 1 s, but not if it is more than 5 min.
• the second hydrophilic layer is applied in generally the same way as the first.
• the spray or immersion solutions used have approximately the same concentration.
• the coated carrier is expediently dried at temperatures from 100 to 130 ° C.
• the determination of the weight of the applied hydrophilic coating is problematic since even small amounts of the product show a clear hydrophilizing effect.
• the hydrophilizing agents also adhere relatively strongly to the surface of the carrier material.
• the amount applied is in any case below 0.5 mg / dm2, in particular below 0.25 mg / dm2.
• the minimum amount is about 0.02 mg / dm2.
• the quantities given apply individually to each of the two levels.
• modified polyethyleneimine and the modified polyvinylamine and processes for their preparation are described in EP-A 0 490 231. They are generally made from polyethyleneimines and polyvinylamines by phosphonomethylation and / or sulfomethylation.
• the carrier materials according to the invention can then be coated with various light-sensitive mixtures.
• all mixtures are suitable which produce layers which, after imagewise exposure, subsequent development and / or fixing, give a positive or negative image.
• the material suitable as a printing plate retains its excellent hydrophilicity and practically no longer shows any color fog.
• the present invention therefore also relates to a recording material with a support made of aluminum or its alloys and a radiation-sensitive layer, which is characterized in that the support is hydrophilized as described above.
• 0.3 mm thick bright rolled aluminum (DIN material no. 3.0255) was degreased with a 2% aqueous NaOH pickling solution at a temperature of 50 to 70 ° C.
• the electrochemical roughening of the surface was then carried out with alternating current in an electrolyte containing HNO 3.
• the R z value of the surface roughness was then 6 ⁇ m.
• the subsequent anodic oxidation was carried out in an electrolyte containing sulfuric acid.
• the oxide layer weight was about 3.0 g / m2.
• 0.3 mm thick bright rolled aluminum (DIN material no. 3.0515) was degreased with a 2% aqueous NaOH pickling solution at a temperature of 50 to 70 ° C.
• the surface was electrochemically roughened using alternating current in an electrolyte containing hydrochloric acid.
• the R z value of the surface roughness was then 6 ⁇ m.
• the subsequent anodic oxidation was carried out in an electrolyte containing sulfuric acid.
• the oxide layer weight was about 2.0 g / m2.
• 0.2 mm thick bright rolled aluminum (DIN material no. 3.0255) was degreased with a 2% aqueous NaOH pickling solution at a temperature of 50 to 70 ° C and then mechanically roughened with cutting grains (e.g. quartz powder or aluminum oxide). The R z value of the surface roughness was then 4 ⁇ m. The subsequent anodic oxidation was carried out in an electrolyte containing phosphoric acid. The oxide layer weight was about 0.9 g / m2.
• This carrier corresponds to that of type 2, with the only difference that it has been anodized up to an oxide layer weight of 1.5 g / m 2.
• a carrier of type 2 was hydrophilized in accordance with Table 1 and consisting of a positive working diazo layer 5.00% by weight cresol-xylenol-formaldehyde novolak resin with a hydroxyl number of 420 according to DIN 53783/53240 and a weight average according to GPC of 6000 (polystyrene standard), 1.20% by weight of ester from 1.5 mol of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride and 1 mol of 2,3,4-trihydrorybenzophenone, 0.15% by weight of 1,2-naphthoquinone-2-diazide-4-sulfonyl chloride, 0.05% by weight victoria pure blue (CI 44045) and ad 100% by weight of a solvent mixture of methyl ethyl ketone and propylene glycol monomethyl ether (40/60) Mistake.
• the coated support was dried at 125 ° C for 1 min.
• the film weight was 2.4 g / m2.
• a matting solution (a 20% aqueous solution of a terpolymer of vinylsulfonic acid, ethyl acrylate and styrene) was then sprayed electrostatically onto the radiation-sensitive layer in such a way that the mean height of the elevations was 4 ⁇ m.
• the plates were contacted in a vacuum contact copier frame by evacuation with a test assembly, exposed with a 5kW metal halide-doped mercury vapor lamp at a distance of 110 cm so that an open step 4 resulted in the UGRA offset test wedge after development, which led to high exposure Film edge removal corresponds.
• developer type 2 O'-bis-carboxymethyl-polyethylene glycol-1000 of 0 , 6 wt .-%
• a type 4 printing plate support was subjected to the four different post-treatments mentioned in Table 1 and provided with a negative working layer of the following composition: 2.5% by weight of a copolymer of methacrylic acid / methyl methacrylate / glycerol monomethacrylate (20/30/50) with an average molecular weight M w of 24,000 (GPC), 0.5% by weight of a diazonium salt polycondensation product of 1 mol of 4-anilino-2-methoxy-benzene diazonium sulfate and 1 mol of 4,4'-bismethoxymethyl-diphenyl ether, precipitated as mesitylene sulfonate, 0.09% by weight victoria pure blue FGA (Basic Blue 81), 0.07% by weight of benzenephosphonic acid, 0.1% by weight of a silica gel filler with an average grain size of 3 ⁇ m and ad 100 wt .-% of a solvent mixture of t
• the coated supports were dried at 120 ° C. in the drying tunnel.
• the dry layer weight was 1.4 g / m2.
• the reproduction layer was exposed for 35 s under a negative original with a 5 kW metal halide lamp and developed with the following solution at 23 ° C. in a developing machine with a rub-out element at 1.4 m / min: 5% by weight sodium lauryl sulfate, 2% by weight phenoxyethanol, 1 wt .-% sodium metasilicate x 5H2O and 92% by weight of water
• the occurrence of residual layer fog is investigated after a developer load of 4 m2 per liter developer.
• hydrophilization E of the carrier according to the invention also proved to be more advantageous here.
• a type 3 support was hydrophilized according to Table 1 and coated with the following solution: 3.1% by weight of 2,5-bis (4-diethylamino-phenyl) -1,3,4-oxadiazole, 3.1% by weight of a copolymer of styrene and maleic anhydride with a softening point of 210 ° C., 0.02% by weight (R) rhodamine FB (CI 45 170), ad 100 wt .-% ethylene glycol monomethyl ether. and then dried in a continuous drying oven at 120 ° C.
• the layer was negatively charged in the dark with a corona to 450 V, the charged plate was exposed imagewise in a repro camera and then with an electrophotographic suspension developer from a dispersion of 0.6% by weight of magnesium sulfate and a solution of 1.4% by weight.
• % Pentaerythritol resin ester developed in 98 wt .-% of an isoparaffin mixture with a boiling range of 185 to 210 ° C.
• the toner was fixed and the plate at 24 ° C in a solution 10% by weight ethanolamine, 10% by weight propylene glycol monophenyl ether, 2% by weight K2HPO4, ad 100 wt .-% water decoated at a processing speed of 1.4 m / min.
• the plate was then rinsed off with a powerful jet of water to remove the remainder of the stripper.
• the occurrence of residual layer veil was investigated after a stripper load of 10 m2 per liter of stripper with an image proportion of 25%.
• a type 1 support was hydrophilized according to Table 1 and a solution of the following composition was spin-coated so that a layer weight of 2.5 g / m 2 was obtained in each case: 10.7% by weight of the terpolymer solution given in Example 3, 5.3% by weight of triethylene glycol dimethacrylate, 0.15% by weight orasol blue (CI 50 315), 0.15% by weight eosin, alcohol-soluble (CI 46 386), 0.11% by weight of 2,4-bis-trichloromethyl-6- (4-styrylphenyl) -s-triazine, 0.23% by weight of dicyclopentadienyl-titanium-bis-pentafluorophenyl, 42% by weight of butanone and ad 100% by weight of butyl acetate.
• the plate was then coated with a layer of polyvinyl alcohol, exposed and developed.
• Examples 6 to 34 (Table 6/7) are intended to show the superiority of the supports according to the invention over the supports of Comparative Examples V1 to V52 hydrophilized according to Tables 1, A to D.
• the recording materials produced according to the conditions given in the tables were examined as follows:
• color veils are visible from a measured value of around 0.8. In any case, they represent a cosmetic defect in the printing plate and can therefore lead to complaints by the buyers. Should the color veil become very intense, this is an indication of a large amount of layer residues in the non-image areas, which can possibly lead to unwanted printing (toning), especially if, as is often desired, little dampening solution is dosed. An exact value of the color veil for this case cannot be given.
• the non-image area of a printing plate was treated with a commercially available correction agent.
• the brightnesses were then measured, once in the corrected and once in the uncorrected area. here too the difference dL * was formed. If it is significantly different from 0, that is to say in the range from 0.5 to 1, the correction means has either been able to remove layer residues from the surface or has even attacked and damaged the surface of the non-image area itself.
• the non-image area of a printing plate was coated with ink using a rubber hand roller, placed in water and the time required for the water to detach the ink from the non-image area. This time must not exceed 30 s for a well hydrophilic carrier.
• Carriers of types 1 and 2 were anodized and treated with an aqueous solution of a polyvinylphosphonic acid in an immersion bath for 5 seconds.
• the conditions are given in Table 3.
• the plates were coated with the solution given in Example 1, exposed and developed with a developer of types 1 or 2 in the above-mentioned developing device VA86.
• Table 3 shows that the printing plates not produced according to the invention in the non-image areas have a sufficiently good hydrophilicity (insofar as they have been determined), but either have a clear color haze or suffer an attack by the correction agent, which leads to discoloration in the non-image areas, or both appearances.
• the recording materials according to Table 4 were produced with a type 2 support and treated with a phosphonomethylated polyimine according to EP-A 0 490 231. This polymer had a molecular weight M w of about 80,000.
• Table 4 No. temperature concentration brightness Color veil Correction contrast Hydrophilicity ° C g / l L * dL * 1 dL * 2 s V13 22 2.0 78.93 2.08 1.75 5 V14 30th 2.0 78.94 0.96 1.28 15 V15 40 2.0 78.95 0.86 1.13 5 V16 50 2.0 79.02 0.53 0.80 5 V17 60 2.0 79.00 0.41 0.76 5 V18 22 1.0 78.97 2.31 1.88 5 V19 30th 1.0 79.01 0.67 0.96 5 V20 40 1.0 78.44 0.57 1.08 5 V21 50 1.0 79.00 0.51 0.62 15 V22 60 1.0 78.96 0.25 0.57 15 V23 22 0.5 79.05 2.06 0.98 5 V24 30th 0.5 79
• V26 has good values, but does not fit into the course of the other samples and must therefore be rated as an outlier. This type of carrier treatment cannot be carried out in a statistically controlled manner and is not suitable for a safe production process.
• Carriers of type 2 in Table 6 and of type 4 in Table 7 were first immersed in an aqueous solution of the phosphonomethylated polyimine and then - after a rinsing step - in an aqueous solution of polyvinylphosphonic acid for 5 s. Diving times of up to a few minutes have the same effect. However, a minimum immersion time of 1 s per bath must be observed. Table 6 No.
• Negative numerical values mean that not only the photosensitive layer was removed during the development process, but the surface of the support was additionally cleaned, which is to be regarded as positive.
• the hydrophilicity is as good as in the other cases.

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• 1994
  • 1994-07-01 DE DE19944423140 patent/DE4423140A1/de not_active Withdrawn
• 1995
  • 1995-06-19 US US08/492,148 patent/US5637441A/en not_active Expired - Fee Related
  • 1995-06-21 ES ES95109599T patent/ES2113696T3/es not_active Expired - Lifetime
  • 1995-06-21 EP EP19950109599 patent/EP0689941B1/fr not_active Expired - Lifetime
  • 1995-06-21 DE DE59501625T patent/DE59501625D1/de not_active Expired - Fee Related
  • 1995-07-03 BR BR9503065A patent/BR9503065A/pt not_active Application Discontinuation
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