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
  • B41N3/038—Treatment with a chromium compound, a silicon compound, a phophorus compound or a compound of a metal of group IVB; Hydrophilic coatings obtained by hydrolysis of organometallic compounds
• • 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

Definitions

• the invention relates to plate; foil or ribbon-shaped carrier materials for offset printing plates based on aluminum with a hydrophilic coating, a process for the production of these materials and the use of the materials in the production of offset printing plates.
• Backing materials for offset printing plates are provided either by the consumer directly or by the manufacturer of precoated printing plates on one or both sides with a light-sensitive layer (copying layer), with the aid of which a printing image is generated photomechanically.
• the support carries the printing image areas and at the same time forms the hydrophilic background for the lithographic printing process in the non-image areas (non-image areas).
• Aluminum, steel, copper, brass or zinc, but also plastic films or paper can be used as the base material for such layers. These raw materials are processed through suitable operations such as e.g. Grain, matt chrome plating, surface oxidation and / or application of an intermediate layer are converted into layer supports for offset printing plates.
• Aluminum, which is probably the most frequently used base material for offset printing plates today, is roughened on the surface by known methods by dry brushing, wet brushing, sandblasting, chemical and / or electrochemical treatment. In order to increase the abrasion resistance, the roughened substrate can also be subjected to an anodization step to build up a thin oxide layer.
• the carrier materials in particular anodically oxidized carrier materials based on aluminum, are subjected to a further treatment step to improve the layer adhesion, to increase the hydrophilicity and / or to facilitate the developability of the light-sensitive layers before the application of a light-sensitive layer for example the following methods:
• the use of salts of these compounds is also mentioned, but is not specified in detail.
• DE-AS 10 91 433 discloses the hydrophilization of printing plate support materials based on metals with film-forming organic polymers such as polymethacrylic acids or sodium carboxymethyl cellulose or - hydroxyethyl cellulose in aluminum supports or a mixed polymer of methyl vinyl ether and maleic anhydride in magnesium supports.
• water-soluble polyfunctional amino-urea-aldehyde synthetic resins or sulfonated urea-aldehyde synthetic resins are first used, which are in a water-insoluble state on the metal support be cured.
• a) an aqueous dispersion of a modified urea-formaldehyde resin, an alkylated methylol-melamine resin or one of the following is first used on the support to produce a hydrophilic layer on printing plate support materials Melamine-formaldehyde-polyalkylene polyamine resin applied, b) an aqueous dispersion of a polyhydroxy or Polycarboxy compound such as sodium carboxymethyl cellulose, and finally the substrate c) thus coated is treated with an aqueous solution of a Zr, Hf, Ti or Th salt.
• the hydrophilic layer on a printing plate support material according to DE-PS 21 07 901 is formed from a water-insoluble hydrophilic acrylate or methacrylate homopolymer or copolymer with a water absorption of at least 20% by weight.
• the layer weight of the hydrophilic adhesive layer on cellulose ether is 0.2 to 1.1 mg / dm 2 , and the same layer weight is also given for the water-soluble salts.
• the mixture of cellulose ether and salt is applied to the support in aqueous solution, optionally with the addition of an organic solvent and / or a surfactant.
• hydrophilizing agents for printing plate support materials according to US Pat. No. 4,049,746 contain salt-like reaction products from water-soluble polyacrylic resins with carboxyl groups and polyalkyleneimine-urea-aldehyde resins.
• hydrophilic colloids such as hydroxyethyl cellulose, polyacrylamide, polyethylene oxide, polyvinyl pyrrolidone, starch or gum arabic are described as hydrophilizing agents for anodized aluminum printing plate supports.
• the object of the invention is therefore to modify the hydrophilicity of support materials for offset printing plates in such a way that they are equally suitable as supports for positive, negative or electrophotographic light-sensitive layers without the aforementioned disadvantages of known modification methods occurring.
• the invention is based on the known plate, foil or tape-shaped carrier materials for offset printing plates based on chemically, mechanically and / or electrochemically roughened aluminum, optionally having an aluminum oxide layer produced by anodic oxidation, or one of its alloys with a hydrophilic coating of at least one hydrophilic organic polymers on at least one surface of the carrier material.
• the carrier materials according to the invention are then characterized in that the hydrophilic organic polymer is a complex reaction product of a) a water-soluble organic polymer with acidic, phosphorus or sulfur-containing functional groups and b) a salt of an at least divalent metal cation.
• the complex reaction products 1 to 3, preferably 2, coordination sites of the metal cation are occupied by the functional groups of the polymer, which probably acts as a chelating ligand.
• the water-soluble polymers used to prepare the complex reaction products are, in particular, polvinylphosphonic acid, polyvinylmethylphosphinic acid, a phosphoric acid ester of polyvinyl alcohol, polyvinylsulfonic acid, polyvinylbenzenesulfonic acid, a sulfuric acid ester of polyvinyl alcohol or an acetal of polyvinyl alcohol and a sulfonated aliphatic aldehyde.
• polyvinylmethylphosphinic acid these compounds are known from the literature.
• polyvinylmethylphosphinic acid is described for the first time in the simultaneously filed patent application P 31 26 627.4 (internal name Hoe 81 / K 038) entitled "Polyvinylmethylphosphinic acid, process for its preparation and its use”; it is produced by polymerizing vinylmethylphosphinic acid or its salts in the presence of radicals, by the action of electromagnetic radiation or by heating.
• the metal cations are generally used in the form of their salts with mineral acid anions or as acetates; the divalent, trivalent or tetravalent, in particular the divalent, are preferred.
• the cations are in particular V S + -, Bi3 + -, At 3 + -, Fe 3 + -, Zr 4 + -, Sn4 + -, Ca2 + -, Ba2 + -, Sr2 + -, Ti3 + -, Co2 + -, Fe2 + -, Mn 2 + -, Ni2 + -, Cu 2 + -, Zn 2 + - or Mg 2 + -tonen.
• the metal cation is usually present both in aqueous solution and in the solid state as an octahedral complex, preferably two of the six coordination sites being occupied by the functional groups of the polymer and the four remaining coordination sites by anions of the salt used, Hydroxyl ions, amine ligands and, to an overwhelming extent, water or completely filled with water.
• these products are soluble in more or less acidic media and are precipitated quantitatively when the acidic solution is neutralized with alkali hydroxide or ammonia; they are insoluble in neutral or alkaline aqueous and in the usual organic solvents.
• the products can be precipitated by neutralizing the reaction solution with dilute alkali hydroxide or ammonia solutions, the unreacted starting products remaining in the solution.
• the yields of these reactions are over 90%.
• the salt forms with a monovalent cation such as sodium or ammonium salt instead of the described acid forms of the polymers.
• reaction products should be predominantly in acidic solutions; when aqueous alkali hydroxide or ammonia solutions are added, a large number of ligand exchange reactions are possible on such complexes. Since the functional groups of the polymers used to synthesize the complex reaction products can themselves interact with the metal cation as bidentate ligands, the following complex structures are also possible as reaction products:
• Such chelate complexes arise in particular if the polymer solution is slowly added to an excess of the metal salt.
• the isolated and dried complex reaction products are preferably in 0.1 to 10%, in particular 0.5 to 3%, mineral acids, preferably phosphoric acid, in concentrations of 0.05 to 5%. , especially in concentrations of 0.1 to 1%.
• the treatment of these substrates with the solutions of the complex reaction products is expediently carried out by dipping formats or by passing the substrate tape through a bath of these solutions. Temperatures of 20 ° to 95 ° C., preferably 25 ° to 60 ° C., have been found and residence times of 2 seconds to 10 minutes, preferably from 10 seconds to 3 minutes, are the most favorable for practical use. An increase in the bath temperature favors the chemisorption of the polymer-metal complexes on the substrate. This makes it possible to reduce the dwell times considerably, particularly in the case of continuous strip treatment.
• the immersion treatment is then expediently followed by a rinsing step with water, primarily with tap water.
• This rinsing process can serve on the one hand to remove excess treatment solution from the support, on the other hand the acidic treatment solution on the support is shifted so strongly towards the neutral point by dilution with water that the dissolved complexes can precipitate in the pores of the substrate and thus on the substrate Carriers are firmly fixed.
• the substrate treated in this way is then expediently dried at temperatures of 110 ° to 130 ° C.
• the treatment of the aluminum substrate can also be carried out as a two-stage process.
• the substrate is immersed, for example, in a 0.2 to 10%, preferably 0.5 to 5%, aqueous solution of the starting polymer.
• the substrate can then be transferred to a second bath without prior rinsing or drying, which contains a 0.1% to saturated, preferably 0.5 to 10% aqueous salt solution with the polyvalent metal ions listed above.
• the rinsing and drying is carried out as in the one-step process.
• the complex reaction products described above are formed on the substrate during the treatment.
• This process variant can also be used to apply the complex reaction products of trivalent metal ions, which are sparingly soluble in strongly acidic media, to the substrate.
• the support materials according to the invention thus produced can then be coated with various light-sensitive layers for the production of offset printing plates.
• the aluminum support materials for printing plates which are very common in practice, are generally mechanically (e.g. by brushing and / or with abrasive treatments), chemically (e.g. by etching agents) or electrochemically (e.g. B. roughened by AC treatment in aqueous HCI or HN0 3 solutions).
• Aluminum printing plates with electrochemical roughening are used in particular for the present invention.
• the process parameters in the roughening stage are in the following ranges: the temperature of the electrolyte between 20 and 60 ° C, the active ingredient (acid, batch) concentration between 5 and 100 g / I, the current density between 15 and 130 A / dm 2 , the residence time between 10 and 100 sec and the electrolyte flow rate on the surface of the workpiece to be treated between 5 and 100 cm / sec; AC is usually used as the type of current, but modified types of current such as AC with different amplitudes of the current strength are also possible for the anode and cathode currents.
• the average roughness depth R z of the roughened surface is in the range from about 1 to 15 ⁇ m, in particular in the range from 4 to 8 ⁇ m.
• the roughness depth is determined in accordance with DIN 4768 in the version from October 1970, the roughness depth R z is then the arithmetic mean of the individual roughness depths of five adjacent individual measuring sections.
• the individual roughness depth is defined as the distance between two parallels to the middle line that touch the roughness profile at the highest or lowest point within the individual measurement sections.
• the individual measuring section is the fifth part of the length of the part of the roughness profile which is used directly for evaluation and is projected perpendicularly onto the middle line.
• the middle line is the line parallel to the general direction of the roughness profile from the shape of the geometrically ideal profile, which divides the roughness profile so that the sum of the material-filled areas above it and the material-free areas below it are equal.
• Direct current is preferably used for the anodic oxidation, however alternating current or a combination of these types of current (eg direct current with superimposed alternating current) can also be used.
• the layer weights of aluminum oxide range from 1 to 10 g / m 2 , corresponding to a layer thickness of approximately 0.3 to 3.0 ⁇ m.
• all layers are suitable as light-sensitive layers which, after exposure, optionally with subsequent development and / or fixation, provide an imagewise surface from which printing can take place. They are either applied by the manufacturer of presensitized printing plates or directly by the consumer on one of the usual carrier materials.
• Negative-working condensation products from aromatic diazonium salts and compounds with active carbonyl groups preferably condensation products from diphenylamine diazonium salts and formaldehyde, which are described, for example, in DE-PS 596 731, 1 138 399, 1 138 400, 1 138 401, 1 142 871, 1 154 123 U.S. Patents 2,679,498 and 3,050,502 and British Patent 712,606.
• Negative mixed condensation products of aromatic diazonium compounds for example according to DE-OS 20 24 244, which each have at least one unit of the general types A (-D) and B connected by a double-bonded intermediate member derived from a condensable carbonyl compound.
• A is the remainder of a compound containing at least two aromatic carbocyclic and / or heterocyclic nuclei, which is capable of condensing with an active carbonyl compound in an acidic medium at at least one position.
• D is a diazonium salt group attached to an aromatic carbon atom of A; n is an integer from 1 to 10; and B is the remainder of a compound free of diazonium groups and capable of condensing with an active carbonyl compound in an acidic medium at at least one position on the molecule.
• Positive-working layers according to DE-OS 26 10 842 which contain a compound which releases acid upon irradiation, a compound which has at least one C-O-C group which can be split off by acid (e.g. an orthocarboxylic acid ester group or a carboxylic acid amide acetal group) and optionally a binder
• the monomers used here are, for example, acrylic and methacrylic acid esters or reaction products of diisocyanates with partial esters of polyhydric alcohols, as described, for example, in US Pat. Nos. 2,760,863 and 3,060,023 and DE-OSes 20 64 079 and 23 61 041.
• photoinitiators are u. a. Benzoin, benzoin ethers, multinuclear quinones, acridine derivatives, phenazine derivatives, quinoxaline derivatives, quinazoline derivatives or synergistic mixtures of different ketones.
• soluble organic polymers can be used as binders, e.g. B. polyamides, polyesters, alkyd resins, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, gelatin or cellulose ether.
• Negative working layers according to DE-OS 30 36 077, which as a photosensitive compound Contain diazonium salt polycondensation product or an organic azido compound and as a binder a high molecular weight polymer with pendant alkenylsulfonyl or cycloalkenylsulfonylurethane groups.
• photoconductive layers such as z. B. in DE-PS 11 17 391.15 22 497.15 72 312.23 22 046 and 23 22 047 are described, applied to the carrier materials produced according to the invention, whereby highly light-sensitive, electrophotographic printing plates are formed.
• offset printing plates obtained from the carrier materials according to the invention are converted into the desired printing form in a known manner by imagewise exposure or irradiation and washing out of the non-image areas with a developer, preferably an aqueous developer solution.
• a developer preferably an aqueous developer solution.
• Example 1 0.2 M 1, based on a vinylphosphonic acid unit, of the polyvinylphosphonic acid is dissolved in 600 ml of water at 25.degree. 0.2 M 1 CO (NO 3 ) 2 dissolved in 200 ml water is then slowly added dropwise to this solution; after the addition has ended, the mixture is stirred for a further hour. The reaction solution is then neutralized by slowly adding dilute aqueous NaOH solution, during which the cobalt complex precipitates quantitatively as a viscous, rubbery, violet-colored precipitate. This precipitate is filtered off, washed with water and then washed with methanol and dried at 60 ° C in a drying cabinet, the excess C 0 2 + ions remain in the filtrate.
• the other polymers can also be reacted with at least divalent metal cations in the same way.
• a bright rolled aluminum strip with a thickness of 0.3 mm is degreased with an aqueous alkaline 2% pickling solution at an elevated temperature of around 50 ° to 70 ° C.
• the electrochemical roughening of the aluminum surface is carried out with alternating current and in an electrolyte containing HN0 3 , a surface roughness having an Rz value of 6 ⁇ m being obtained.
• the subsequent anodic oxidation is carried out in accordance with the process described in DE-OS 28 11 396 in an electrolyte containing sulfuric acid Oxide weight is 3.0 g / m2.
• the aluminum strip prepared in this way is then passed through a 25 ° C. bath from a 0.5% solution (in 2% H 3 PO 4 ) of the polymer-metal complex composed of polyvinylphosphonic acid and CO 2 + ions.
• the residence time in the bath is 30 seconds.
• the excess solution is then removed with tap water in a rinsing step and the strip is dried with hot air at temperatures between 100 ° and 130 ° C.
• the printing plate produced in this way can be developed quickly and free of fog.
• the non-image areas are characterized by a very good ink-repelling effect.
• the contact angle measurement compared to a drop of water gave a value of 18 ° for the stripped material, the print run was 200,000.
• the printing forms received are free of copying and printing technology.
• the non-image areas have a very good ink-repellent effect, which manifests itself in the fast free running of the printing form in the printing press.
• the print run is 120,000.
• Example 5 An electrochemically roughened (R, -3 .mu.m) and anodized aluminum sheet is post-treated and coated in accordance with Example 5.
• the printing plates produced in this way are distinguished by the same advantages as indicated in Example 5.
• the printing form thus produced is distinguished by a significantly improved ink-repelling effect of the non-image areas.
• Example 2 An aluminum sheet which had been electrochemically roughened and anodized in accordance with Example 2 was immersed in a 1% strength aqueous solution of polyvinylphosphonic acid at 50 ° C. for 30 seconds. When removing the The excess solution is scraped off the surface of substrate from the bath. Then the still moist substrate in a 2% aqueous solution of Al (N0 3 ) 3rd 9 H 2 0 immersed for 30 sec at room temperature, it is rinsed with tap water and dried with hot air (100 to 130 ° C). The substrate treated in this way is then coated with the light-sensitive solution described in Example 3, exposed and developed.
• the printing plate produced in this way can be developed quickly and free of fog, the non-image areas are characterized by a very good ink-repelling effect.
• the contact angle measurement compared to a drop of water gave a value of 10 ° on the non-image areas.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Printing Plates And Materials Therefor (AREA)
• Reinforced Plastic Materials (AREA)
• Manufacture Or Reproduction Of Printing Formes (AREA)
• Treating Waste Gases (AREA)
• Detergent Compositions (AREA)
• Laminated Bodies (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)

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Publications (2)

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• 1981
  • 1981-07-06 DE DE19813126636 patent/DE3126636A1/de not_active Withdrawn
• 1982
  • 1982-06-21 ZA ZA824358A patent/ZA824358B/xx unknown
  • 1982-06-22 CA CA000405713A patent/CA1178857A/en not_active Expired
  • 1982-06-23 US US06/391,131 patent/US4427765A/en not_active Expired - Lifetime
  • 1982-06-28 EP EP82105718A patent/EP0069320B1/de not_active Expired
  • 1982-06-28 AT AT82105718T patent/ATE20327T1/de not_active IP Right Cessation
  • 1982-06-28 DE DE8282105718T patent/DE3271644D1/de not_active Expired
  • 1982-07-02 FI FI822366A patent/FI822366L/fi not_active Application Discontinuation
  • 1982-07-05 ES ES513734A patent/ES513734A0/es active Granted
  • 1982-07-05 BR BR8203904A patent/BR8203904A/pt not_active IP Right Cessation
  • 1982-07-05 AU AU85587/82A patent/AU556302B2/en not_active Ceased
  • 1982-07-06 JP JP57116332A patent/JPS5816893A/ja active Granted
• 1983
  • 1983-10-25 ES ES526743A patent/ES526743A0/es active Granted

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