EP0190643B1 - Hydrophilized suppport material for lithographic printing plates, their production and use - Google Patents

Description

The invention relates to plate, film 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. Carrier materials for offset printing plates are either directly from the consumer or. provided by the manufacturer of pre-coated printing plates on one or both sides with a light-sensitive layer (copying layer), with the help of which a printing image is generated in a photomechanical way. After the printing image has been produced, 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).

• -Die nach der Belichtung relativ löslicheren Teile der lichtempfindlichen Schicht müssen durch eine Entwicklung leicht zur Erzeugung der hydrophilen Nichtbildstellen rückstandsfrei vom Träger zu entfernen sein.
• -Der in den Nichtbildstellen freigelegte Träger muß eine große Affinität zu Wasser besitzen, d. h. stark hydrophil sein, um beim lithographischen Druckvorgang schnell und dauerhaft Wasser aufzunehmen und gegenüber der fetten Druckfarbe ausreichend abstoßend zu wirken.
• -Die Haftung der lichtempfindlichen Schicht vor, bzw. der druckenden Teile der Schicht nach der Belichtung muß in einem ausreichenden Maß gegeben sein.

The following requirements must therefore be placed on a layer support for light-sensitive material for the production of lithographic plates:

• The parts of the photosensitive layer which are relatively more soluble after exposure must be easy to remove from the support without residue by development to produce the hydrophilic non-image areas.
• The carrier exposed in the non-image areas must have a high affinity for water, ie it must be highly hydrophilic in order to absorb water quickly and permanently during the lithographic printing process and to be sufficiently repellent to the bold printing ink.
• The adhesion of the light-sensitive layer before or the printing parts of the layer after exposure must be sufficient.

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.

In practice, the support materials, in particular anodically oxidized support materials based on aluminum, are often 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:

In DE-C 907 147 (= US-A 2 714 066), DE-B 14 71 707 (= US-A 3 181 461 and US-A 3 280 734) or DE-A 25 32 769 (= US Pat. No. 3,902,976) describes processes for the hydrophilization of printing plate support materials based on optionally anodically oxidized aluminum, in which these materials are treated with aqueous sodium silicate solution without or with the use of electric current.

From DE-A 11 34 093 (= US-A 3 276 868) and DE-C 16 21 478 (= US-A 4 153461) it is known to use polyvinylphosphonic acid or copolymers based on vinylphosphonic acid, acrylic acid and vinyl acetate Hydrophilization of printing plate support materials based on anodized aluminum, if necessary. The use of salts of these compounds is also mentioned, but is not specified in detail.

The use of complex fluorides of titanium, zircon or hafnium according to DE-B 13 00 415 (= US-A 3 440 050) also leads to additional hydrophilization of aluminum oxide layers on printing plate support materials.

In addition to these particularly well-known hydrophilization methods, the use of the following polymers in this field of application has also been described, for example:

DE-B 10 56 931 describes the use of water-soluble, linear copolymers based on alkyl vinyl ethers and maleic anhydrides in light-sensitive layers for printing plates. Of these copolymers, those in which the maleic anhydride component has not been reacted with, or more or less completely, with ammonia, an alkali metal hydroxide or an alcohol are particularly hydrophilic.

DE-B 10 91 433 discloses the hydrophilization of printing plate support materials based on metals with film-forming organic polymers such as polymethacrylic acid or sodium carboxymethyl cellulose or hydroxyethyl cellulose in the case of aluminum supports or a mixed polymer of methyl vinyl ether and maleic anhydride in the case of magnesium supports.

For the hydrophilization of printing plate support materials made of metals according to DE-B 11 73 917 (= GB-A 907 718), 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.

According to DE-B 12, a hydrophilic layer on printing plate carrier materials is produced 00 847 (= US Pat. No. 3,232,783) initially a) an aqueous dispersion of a modified urea-formaldehyde resin, an alkylated methylol-melamine resin or a melamine-formaldehyde-polyalkylene polyamine resin, then b) an aqueous dispersion Dispersion of a polyhydroxy or polycarboxy compound such as sodium carboxymethyl cellulose, and finally the base c) thus coated is treated with an aqueous solution of a Zr, Hf, Ti or Th salt.

DE-B 12 57 170 (= US-A 2 991 204) describes a copolymer as a hydrophilizing agent for printing plate support materials which, in addition to acrylic acid, acrylate, acrylamide or methacrylamide units, also contains Si-trisubstituted vinylsilane units.

DE-A 14 71 706 (= US-A 3 298 852) discloses the use of polyacrylic acid as a hydrophilizing agent for printing plate support materials made of aluminum, copper or zinc.

The hydrophilic layer on a printing plate support material according to DE-C 21 07 901 (= US-A 3 733 200) is formed from a water-insoluble hydrophilic acrylate or methacrylate homopolymer or copolymer with a water absorption of at least 20% by weight.

DE-B 23 05 231 (= GB-A 1 414 575) describes a hydrophilization of printing plate support materials in which a solution or dispersion of a mixture of an aldehyde and a synthetic polyacrylamide is applied to the support.

DE-A 23 08 196 (= US-A 3 861 917) describes the hydrophilization of roughened and anodized aluminum printing plate supports with ethylene or methyl vinyl ether-maleic anhydride copolymers, polyacrylic acid, carboxymethyl cellulose, sodium poly (vinylbenzene-2, 4-disulfonic acid) or polyacrylamide.

DE-B 23 64 177 (= US-A 3 860 426) describes a hydrophilic adhesive layer for aluminum offset printing plates, which is arranged between the anodized surface of the printing plate support and the light-sensitive layer and, in addition to a cellulose ether, a water-soluble Zn- , Ca, Mg, Ba, Sr, Co or Mn salt contains. 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.

For sealing anodically oxidized aluminum surfaces according to US Pat. No. 3,672,966, aqueous solutions of acrylic acid, polyacrylic acid, polymethacrylic acid, polymaleic acid or copolymers of maleic acid with ethylene or vinyl alcohol are used after their sealing to avoid seal deposits.

The hydrophilizing agents for printing plate support materials according to US Pat. No. 4,049,746 contain salt-like reaction products of water-soluble polyacrylic resins with carboxyl groups and polyalkyleneimine-urea-aldehyde resins.

GB-A 1 246 696 describes hydrophilic colloids such as hydroxyethyl cellulose, polyacrylamide, polyethylene oxide, polyvinyl pyrrolidone, starch or gum arabic as hydrophilizing agents for anodized aluminum printing plate supports.

From JP-A 64/23 982 a hydrophilization of metal printing plate supports with polyvinylbenzenesulfonic acid is known.

• -Komplexionen aus zwei- oder mehrwertigen Metallkationen und Liganden wie Ammoniak, Wasser, Ethylendiamin, Stickstoffoxid, Harnstoff oder Ethylendiamintetraacetat nach der DE-A 28 07 396 (= US-A 4 208 212),
• -Eisencyanid-Komplexe wie K_4[Fe(CN)_s] oder Na_3[Fe(CN)e] in Anwesenheit von Heteropolysäuren wie Phosphormolybdänsäure oder ihren Salzen und von Phosphaten nach der US-A 3 769 043 oder und US-A 4 420 549 oder
• -Eisencyanid-Komplexe in Anwesenheit von Phosphaten und Komplexbildnern wie Ethylendiamintetraessigsäure für elektrophotographische Druckplatten mit Zinkoxidoberfläche nach der NL-A 68 09 658 (= US-A 3 672 885).

. The use of metal complexes of this type for hydrophilizing printing plate support materials which have low molecular weight ligands has also become known from the prior art, for example:

• Complex ions of divalent or polyvalent metal cations and ligands such as ammonia, water, ethylenediamine, nitrogen oxide, urea or ethylenediaminetetraacetate according to DE-A 28 07 396 (= US-A 4 208 212),
• Iron cyanide complexes such as K _{4 [} Fe (CN) _s] or Na _{3 [} Fe (CN) e] in the presence of heteropolyacids such as phosphomolybdic acid or its salts and phosphates according to US Pat. No. 3,769,043 or US Pat. No. 4 420 549 or
• Iron cyanide complexes in the presence of phosphates and complexing agents such as ethylenediaminetetraacetic acid for electrophotographic printing plates with a zinc oxide surface according to NL-A 68 09 658 (= US Pat. No. 3,672,885).

EP-A 0 069 320 (= US-A 4 427 765) describes a process in which salts of polyvinylphosphonic acids, polyvinylsulfonic acids, polyvinylmethylphosphinic acids and other polyvinyl compounds are used as aftertreatment agents.

US Pat. No. 4,214,531 uses a process for treating image-bearing offset printing plates with polyacrylamide or a mixture of polyacrylamide and polyacrylic acid.

SU-A 647 142 uses a copolymer of acrylamide and vinyl monomers for the hydrophilization of offset printing plates.

In DE-C 26 15 075 (= GB-A 1 495 895) a polyacrylamide is used for the same purpose.

DE-C 10 91 433 describes a process for the aftertreatment of offset printing plate supports with polymers of methacrylic acid, methyl vinyl ether and maleic anhydride.

Acrylamide for the treatment of printing plate supports is also mentioned in DE-A 25 40 561.

For the same purpose, in particular to improve the shelf life of printing plates, DE-A 29 47 708 describes u.a. Ni salt solutions of acrylamide and acrylic acid as well as acrylamide and vinyl pyrrolidone.

• -So muß nach der Behandlung mit Alkalisilikaten, die zu guter Entwickelbarkeit und Hydrophilie führen, eine gewisse Verschlechterung der Lagerfähigkeit von darauf aufgebrachten lichtempfindlichen Schichten hingenommen werden.
• -Die Komplexe der Ubergangsmetalle begünstigen zwar prinzipiell die Hydrophilie von anodisch oxidierten Aluminiumoberflächen, sie haben jedoch den Nachteil, sehr leicht in Wasser löslich zu sein, so daß sie beim Entwickeln der Schicht mit wäßrigen Entwicklersystemen, die neuerdings in zunehmendem Maße Tenside und/oder Chelatbildner enthalten, die eine große Affinität zu diesen Metallen besitzen, leicht entfernt werden können. Dadurch wird die Konzentration der Übergangsmetallkomplexe auf der Oberfläche mehr oder weniger stark reduziert, was zu einer Abschwächung der hydrophilen Wirkung führen kann.
• -Bei der Behandlung von Trägern mit wasserlöslichen Polymeren führt deren gute Löslichkeit besonders in wäßrig-alkalischen Entwicklern, wie sie überwiegend zum Entwickeln von positiv arbeitenden lichtempfindlichen Schichten verwendet werden, ebenfalls zur deutlichen Abschwächung der hydrophilierenden Wirkung.
• -Bei Säuregruppen enthaltenden Polymeren macht sich negativ bemerkbar, daß freie anionische Säurefunktionen mit den Diazokationen von negativ arbeitenden lichtempfindlichen Schichten in Wechselwirkung treten können, so daß nach dem Entwickeln auf den Nichtbildstellen ein deutlicher Farbschleier durch zurückgehaltene Diazoverbindungen zurückbleibt.
• -Auch die Kombination eines Gemisches aus einem wasserlöslichen Polymeren wie einem Celluloseether und einem wasserlöslichen Metallsalz führt, da die Schichtgewichte und damit die Schichtstärke relativ hoch gewählt wird (siehe DE-B 23 64 177), zu einer verminderten Schichthaftung, die sich beispielsweise darin äußern kann, daß beim Entwickeln Teile der Entwicklerflüssigkeit Bildstellen unterwandem.

However, all of the methods described above have more or less major disadvantages, so that the carrier materials produced in this way often no longer meet the current requirements of offset printing:

• Thus, after treatment with alkali silicates, which lead to good developability and hydrophilicity, a certain deterioration in the shelf life of photosensitive layers applied thereon must be accepted.
• The complexes of the transition metals favor the hydrophilicity of anodically oxidized aluminum surfaces in principle, but they have the disadvantage of being very easily soluble in water, so that when the layer is developed with aqueous developer systems, they increasingly become surfactants and / or chelating agents contain, which have a great affinity for these metals, can be easily removed. As a result, the concentration of the transition metal complexes on the surface is reduced to a greater or lesser extent, which can weaken the hydrophilic effect.
• When treating carriers with water-soluble polymers, their good solubility, particularly in aqueous alkaline developers, as are predominantly used for developing positive-working light-sensitive layers, also leads to a marked weakening of the hydrophilizing effect.
• In the case of polymers containing acid groups, it has a negative effect that free anionic acid functions can interact with the diazo cations of negative-working photosensitive layers, so that after development on the non-image areas a clear color haze remains due to retained diazo compounds.
• The combination of a mixture of a water-soluble polymer such as a cellulose ether and a water-soluble metal salt also leads to a reduced layer adhesion, which is expressed, for example, because the layer weights and thus the layer thickness are chosen to be relatively high (see DE-B 23 64 177) can that parts of the developer liquid undermine image areas during development.

The object of the invention is therefore to produce support materials for offset printing plates with good hydrophilization properties that they are equally suitable as supports for positive, negative or electrophotographic photosensitive layers without reducing the shelf life, reactions between the hydrophilizing agent and the photosensitive layer occur or that Shift liability is reduced.

The invention is based on a plate, film or tape-shaped carrier material for offset printing plates consisting of optionally pretreated aluminum or one of its alloys, which has a hydrophilic coating of a phosphonic acid compound on at least one side.

The characteristic feature is that the hydrophilic coating consists of a) a polymer of acrylamidoisobutylenephosphonic acid or b) a copolymer of acrylamide and acrylamidoisobutylenephosphonic acid or c) a salt of a) or b) with at least one divalent metal cation.

In the copolymeric salts, 1 to 3, preferably 2, coordination sites of the metal cation are occupied by the functional groups of the polymer.

To prepare the reaction products of variants c), 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 ^{5 + -} , Bis + -, A13 + -, Fe3 ^{+ -} , Zr4 ^{+ -} , Sn4 ^{+ -} , Ca2 + -, Ba2 + ^- , Sr ^{2 + -} , ^T J3 + -, Co2 ^{+ -} , Fe2 ^{+ -} , Mn2 + -, Ni2 + -, Cu2 ^{+ -} , Zn2 + ^- or Mg ^{2 + -} ions.

These reaction products can be prepared in a simple manner in aqueous solution at temperatures from 20 to 100 _° C., preferably at 25 to 40 _° C. The metal salt is slowly added dropwise to the aqueous polymer solution, dissolved in water or, if necessary, dissolved in dilute mineral acid. This leads to the immediate conversion of the reaction components to the previously described products. The rapid onset of reaction is shown - depending on the metal cation used - in the immediately changing color of the solution or through the formation of precipitation.

For purification, 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%. Instead of the acid forms of the polymers described, it is also possible to use their salt forms with a monovalent cation such as sodium or ammonium salt.

wobei insbesondere

• M =Zentralion
• im Falle von 2-wertigen Metallkationen A = B = H₂0 oder im Falle von 3-wertigen Metallkationen A = H₂0 und
• B = N0₃-, Cl-, HS0₄-, H₂P0₄-, CHsCOO-, OH- oder ähnliche Anionen bedeuten.

The chemical structure of the polymer-metal complexes according to the invention can be represented as follows:

being in particular

• M = central ion
• in the case of divalent metal cations A = B = H ₂ 0 or in the case of trivalent metal cations A = H ₂ 0 and
• B = N0 ₃ -, Cl-, HS0 ₄ -, H ₂ P0 ₄ -, CHsCOO-, OH- or similar anions.

Such complexes arise in particular when the polymer solution is slowly added to an excess of the metal salt.

For the treatment of the aluminum surface for the production of the support materials for offset printing plates according to the invention, the aqueous solutions of the copolymers are used in concentrations of 0.02 to 5%, preferably in concentrations of 0.1 to 1%.

For the treatment of the substrates for the production of the support materials for offset printing plates according to the invention with the salts of the copolymers, the isolated and dried 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%, dissolved.

The treatment of these substrates with the solutions 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 of 25 to 60 _° C. and residence times of 2 seconds to 10 minutes, preferably of 10 seconds to 3 minutes, are found to be the most favorable for practical use. An increase in the bath temperature accelerates the chemisorption of the copolymers and 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 advantageously followed by a rinsing step with water. The thus treated substrate is then advantageously dried at of 110 to 130 _° C.

The treatment of the aluminum substrate with the salts of the copolymers can also be carried out as a two-stage process. In the first step, the substrate is immersed, for example, in a 0.01 to 10%, preferably 0.1 to 5%, aqueous solution of the starting polymer. The substrate can then be transferred without prior rinsing or drying into a second bath 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. In the two-stage treatment, the reaction products described above are formed on the substrate during the treatment. This process variant can also be used to apply the reaction products of trivalent metal ions, which are sparingly soluble in strongly acidic media, to the substrate.

Determining the weight of the applied hydrophilic coating is problematic since even small amounts of the applied product have clear effects and are anchored relatively strongly in and on the surface of the carrier material. However, it can be assumed that the amount applied is well below 0.1 mg / dm ² , in particular below 0.08 mg / dm ² .

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.

• -"Reinaluminium" (DIN-Werkstoff Nr. 3.0255), d. h. bestehend aus z 99,5% AI und den folgenden zulässigen Beimengungen von (maximale Summe von 0,5%) 0,3% Si, 0,4% Fe, 0,03% Ti, 0,02% Cu, 0,07% Zn und 0,03% Sonstigem, oder
• -"AI-Legierung 3003" (vergleichbar mit DIN-Werkstoff Nr.3.0515), d. h. bestehend aus ≧ 98,5% Al, den Legierungsbestandteilen 0 bis 0,3% Mg und 0,8 bis 1,5% Mn und den folgenden zulässigen Beimengungen von 0,5% Si, 0,5% Fe, 0,2% Ti, 0,2% Zn, 0,1% Cu und 0,15% Sonstigem.

Suitable substrates for the production of the carrier materials according to the invention include those made of aluminum or one of its alloys. These include, for example:

• - "Pure aluminum" (DIN material no. 3.0255), ie consisting of z 99.5% AI and the following admissible admixtures of (maximum sum of 0.5%) 0.3% Si, 0.4% Fe, 0 , 03% Ti, 0.02% Cu, 0.07% Zn and 0.03% other, or
• - "AI alloy 3003" (comparable to DIN material No. 3.0515), ie consisting of ≧ 98.5% Al, the alloy components 0 to 0.3% Mg and 0.8 to 1.5% Mn and the following admissible admixtures of 0.5% Si, 0.5% Fe, 0.2% Ti, 0.2% Zn, 0.1% Cu and 0.15% other.

However, the method according to the invention can also be applied to other aluminum alloys.

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 HCl or ENT solutions). Aluminum printing plates with electrochemical roughening are used in particular for the present invention.

In general, the process parameters in the roughening stage are in the following ranges: the temperature of the electrolyte between 20 and 60 _° C, the active substance (acid, salt) 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 Rz of the roughened surface is in the range from about 1 to 15 μm, in particular in the range from 4 to 8 μm.

The roughness depth is determined in accordance with DIN 4768 (as of 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, which touch the roughness profile at the highest or lowest point within the individual measuring 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 in such a way that the sum of the material-filled areas above it and the material-free areas below it are equal.

• -Das Gleichstrom-Schwefelsäure-Verfahren, bei dem in einem wäßrigen Elektrolyten aus üblicherweise ca. 230 g H₂S0₄ pro 1 Liter Lösung bei 10 bis 22 °C und einer Stromdichte von 0,5 bis 2,5 A/dm² während 10 bis 60 min anodisch oxidiert wird. Die Schwefelsäurekonzentration in der wäßrigen Elektrolytlösung kann dabei auch bis auf 8 bis 10 Gew.-% H₂S0₄ (ca. 100 g/I H₂S0₄) verringert oder auch auf 30 Gew.-% (365 g/I H₂S0₄) und mehr erhöht werden.
• -Die "Hartanodisierung" wird mit einem wäßrigen H₂S0₄ enthaltenden Elektrolyten einer Konzentration von 166 g/I H₂S0₄ (oder ca. 230 g/l H₂S0₄) bei einer Betriebstemperatur von 0 bis 5 °C, bei einer Stromdichte von 2 bis 3 A/dm², einer steigenden Spannung von etwa 25 bis 30 V zu Beginn und etwa 40 bis 100 V gegen Ende der Behandlung und während 30 bis 200 min durchgeführt.

After the electrochemical roughening process, an anodic oxidation of the aluminum then follows in a further process step, which may be used, in order to improve, for example, the abrasion and adhesion properties of the surface of the carrier material. The usual electrolytes such as H ₂ S0 ₄ , HsP04, H ₂ C ₂ 0 ₄ , amidosulfonic acid, sulfosuccinic acid, sulfosalicylic acid or mixtures thereof can be used for anodic oxidation. Reference is made, for example, to the following standard methods for the use of aqueous electrolytes containing H ₂ S0 ₄ for the anodic oxidation of aluminum (see, for example, M. Schenk, material aluminum and its anodic oxidation, Francke Verlag - Bem, 1948, page 760; Practical electroplating, Eugen G. Leuze Verlag - Saulgau, 1970, page 395 ff and pages 518/519; W.Hübner and CTSpeiser, The practice of anodic oxidation of aluminum, Aluminum Verlag - Düsseldorf, 1977, 3rd edition, pages 137 ff ):

• -The DC-sulfuric acid process, in which in an aqueous electrolyte from usually about 230 g H ₂ S0 ₄ per 1 liter of solution at 10 to 22 ° C and a current density of 0.5 to 2.5 A / dm ² during Is anodized for 10 to 60 min. The sulfuric acid concentration in the aqueous electrolyte solution can also be reduced to 8 to 10% by weight H ₂ S0 ₄ (approx. 100 g / IH ₂ S0 ₄ ) or to 30% by weight (365 g / IH ₂ S0 ₄ ) and more can be increased.
• -The "hard anodization" is carried out with an aqueous electrolyte containing H ₂ S0 _{4 with} a concentration of 166 g / IH ₂ S0 ₄ (or about 230 g / l H ₂ S0 ₄ ) at an operating temperature of 0 to 5 ° C, at a Current density of 2 to 3 A / dm ² , a rising voltage of about 25 to 30 V at the beginning and about 40 to 100 V towards the end of the treatment and carried out for 30 to 200 min.

In addition to the methods for the anodic oxidation of printing plate support materials already mentioned in the previous paragraph, the following methods can also be used, for example: the anodic oxidation of aluminum in an aqueous H ₂ S0 _4- containing electrolyte, the Al ³⁺ ion content of which is more than 12 g / 1 is set (according to DE-A 28 11 396 = US-A 4 211 619), in an aqueous electrolyte containing H ₂ S0 ₄ and H ₃ P0 ₄ (according to DE-A 27 07 810 = US-A 4,049,504) or in an aqueous electrolyte containing H ₂ S0 ₄ , H _s P0 ₄ and Al ^{3 +} ions (according to DE-A 28 36 803 = US Pat ^. No. 4,229,226).

Direct current is preferably used for anodic oxidation, however alternating current or a combination of these types of current (e.g. direct current with superimposed alternating current) can also be used will. The layer weights of aluminum oxide range from 1 to 10 g / m ² , corresponding to a layer thickness of about 0.3 to 3.0 (lm.

In principle, 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.

• positiv arbeitende, o-Chinondiazid-, bevorzugt o-Naphthochinondiazid-Verbindungen, die beispielsweise in den DE-C 854 890,865109,879 203,894 959,938 233,1109 521,1144 705,1118 606,1120 273 und 1 124 817 beschrieben werden;
• negativ arbeitende Kondensationsprodukte aus aromatischen Diazoniumsalzen und Verbindungen mit aktiven Carbonylgruppen, bevorzugt Kondensationsprodukte aus Diphenylamindiazoniumsalzen und Formaldehyd, die beispielsweise in den DE-C 596 731,1138 399,1138 400,1138 401,1142 871,1154123, den US-A 2 679 498 und 3 050 502 und der GB-A 712 606 beschrieben werden; negativ arbeitende, Mischkondensationsprodukte aromatischer Diazoniumverbindungen, beispielsweise nach der DE-A 20 24 244, die mindestens je eine Einheit der allgemeinen Typen A(-D)_n und B verbunden durch ein zweibindiges, von einer kondensationsfähigen Carbonylverbindung abgeleitetes Zwischenglied aufweisen. Dabei sind diese Symbole wie folgt definiert: A ist der Rest einer mindestens zwei aromatische carbo- und/oder heterocyclische Kerne enthaltenden Verbindung, die in saurem Medium an mindestens einer Position zur Kondensation mit einer aktiven Carbonylverbindung befähigt ist. D ist eine an ein aromatisches Kohlenstoffatom von A gebundene Diazoniumsalzgruppe; n ist eine ganze Zahl von 1 bis 10 und B der Rest einer von Diazoniumgruppen freien Verbindung, die in saurem Medium an mindestens einer Position des Moleküls zur Kondensation mit einer aktiven Carbonylverbindung befähigt ist;
• positiv arbeitende Schichten nach der DE-A 26 10 842, die eine bei Bestrahlung Säure abspaltende Verbindung, eine Verbindung, die mindestens eine durch Säure abspaltbare C-O-C-Gruppe aufweist (z.B. eine Orthocarbonsäureestergruppe oder eine Carbonsäureamidacetalgruppe) und gegebenenfalls ein Bindemittel enthalten;
• negativ arbeitende Schichten aus photopolymerisierbaren Monomeren, Photoinitiatoren, Bindemitteln und gegebenenfalls weiteren Zusätzen. Als Monomere werden dabei beispielsweise Acryl- und Methacrylsäureester oder Umsetzungsprodukte von Diisocyanaten mit Partialestern mehrwertiger Alkohole eingesetzt, wie es beispielsweise in den US-A 2 760 863 und 3 060 023 und den DE-A 20 64 079 und 23 61 041 beschrieben wird. Als Photoinitiatoren eignen sich u.a. Benzoin, Benzoinether, Mehrkernchinone, Acridinderivate, Phenazinderivate, Chinoxalinderivate, Chinazolinderivate oder synergistische Mischungen verschiedener Ketone. Als Bindemittel können eine Vielzahl löslicher organischer Polymere Einsatz finden, z. B. Polyamide, Polyester, Alkydharze, Polyvinylalkohol, Polyvinylpyrrolidon, Polyethylenoxid, Gelatine oder Celluloseether;
• negativ arbeitende Schichten gemäß der DE-A 30 36 077, die als lichtempfindliche Verbindung ein Diazoniumsalz-Polykondensationsprodukt oder eine organische Azidoverbindung und als Bindemittel ein hochmolekulares Polymeres mit seitenständigen Alkenylsulfonyl- oder Cycloalkenylsulfonylurethan-Gruppen enthalten.

In addition to the layers containing silver halides used in many fields, various others are also known, as are described, for example, in "Light-Sensitive Systems" by Jaromir Kosar, John Wiley & Sons Verlag, New York 1965: the colloid layers containing chromates and dichromates (Kosar, Chapter 2); the layers containing unsaturated compounds in which these compounds are isomerized, rearranged, cyclized or crosslinked during exposure (Kosar, Chapter 4); the layers containing photopolymerizable compounds, in which monomers or prepolymers optionally polymerize during exposure by means of an initiator (Kosar, chapter); and the layers containing o-diazo-quinones such as naphthoquinonediazides, p-diazo-quinones or diazonium salt condensates (Kosar, Chapter 7). The suitable layers also include the electrophotographic layers, ie those which contain an inorganic or organic photoconductor. In addition to the light-sensitive substances, these layers can of course also contain other constituents such as resins, dyes or plasticizers. In particular, the following light-sensitive compositions or compounds can be used in the coating of the carrier materials produced by the process according to the invention:

• positive-working, o-quinonediazide, preferably o-naphthoquinonediazide compounds, which are described, for example, in DE-C 854 890,865109,879 203,894 959,938 233,1109 521,1144 705,1118 606,1120 273 and 1 124 817;
• 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-C 596 731,1138 399,1138 400,1138 401,1142 871,1154123, US Pat. No. 2,679,498 and 3,050,502 and GB-A 712 606; Negative working, mixed condensation products of aromatic diazonium compounds, for example according to DE-A 20 24 244, which each have at least one unit of the general types A (-D) _n and B connected by a double-bonded intermediate member derived from a condensable carbonyl compound. These symbols are defined as follows: 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 diazonium group-free compound 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-A 26 10 842, which contain a compound which cleaves off on irradiation, a compound which has at least one COC group which can be cleaved off by acid (for example an orthocarboxylic acid ester group or a carboxylic acid amide acetal group) and optionally a binder;
• Negative working layers of photopolymerizable monomers, photoinitiators, binders and optionally other additives. 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-A 20 64 079 and 23 61 041. Suitable photoinitiators include benzoin, benzoin ethers, multinuclear quinones, acridine derivatives, phenazine derivatives, quinoxaline derivatives, quinazoline derivatives or synergistic mixtures of various ketones. A variety of 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-A 30 36 077, which contain a diazonium salt polycondensation product or an organic azido compound as a photosensitive compound and a high molecular weight polymer with pendant alkenylsulfonyl or cycloalkenylsulfonylurethane groups as a binder.

It is also possible to use photo-semiconducting layers such as e.g. in DE-C 11 17 391, 15 22 497.15 72 312, 23 22 046 and 23 22 047 are described, to which carrier materials are applied, which results in highly light-sensitive, electrophotographic layers.

The coated 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. Surprisingly, offset printing plates, the base carrier materials of which have been treated according to the invention, have a significantly lower color haze and improved hydrophilicity compared to plates which have been treated with homopolymeric acrylamide, with polymeric vinylphosphonic acid or only with hot water. Also the liability of the photosensitive Layer on the surface of the support was better in the samples treated according to the invention than in the comparison samples.

Examples A for the production of a roughened and anodized printing plate support

A1: A bright rolled aluminum strip (DIN material No. 3.0255) with a thickness of 0.3 mm is degreased with an aqueous alkaline 2% pickling solution at an elevated temperature of about 50 to 70 _° C. The electrochemical roughening of the aluminum surface is carried out with alternating current and in an electrolyte containing ENT; this results in a surface roughness with an Rr value of 6 µm. The subsequent anodic oxidation is carried out in an electrolyte containing sulfuric acid in accordance with the process described in DE-A 28 11 396; the oxide weight is about 3.0 g / _m 2.

A carrier produced in this way is designated by the number 1 in Tables 2 and 3.

The aluminum strip prepared in this way is then passed through a 60 _° C. bath from a 0.5% solution which contains one of the polymers according to the invention or one of the comparison substances (N1 to NV13). The compositions of these solutions are listed in Table 1. 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. A2: A bright rolled aluminum strip (DIN material no. 3.0515) 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 takes place with alternating current and in an electrolyte containing hydrochloric acid; a surface roughness with an Rz value of 6 11 m is obtained. The subsequent anodic oxidation is carried out in an electrolyte containing sulfuric acid in accordance with the process described in DE-A 28 11 396; the oxide weight is about 3.0 g / m ² .

A carrier produced in this way is designated in Table 2 and 3 with the number 2.

The aluminum strip prepared in this way is then passed through a 50 _° C. bath from a 0.5% solution which contains one of the polymers according to the invention or one of the comparison substances (N1 to NV13). The compositions of these solutions are listed in Table 1.

A3: A bright rolled aluminum strip (DIN material No. 3.0255) with a thickness of 0.2 mm is degreased with an aqueous alkaline 2% pickling solution at an elevated temperature of around 50 to 70 _° C. The carrier is then brushed using cutting agents. This results in a surface roughness with an Rr value of 4 11 m. The subsequent anodic oxidation takes place according to DE-C 16 71 614 (= US-A 3 511 661) in an electrolyte containing phosphoric acid. The oxide weight is 0.9 g / m2. The aluminum strip processed in this way is cut into sheets measuring 50 x 45 cm.

A carrier produced in this way is designated by the number 3 in Tables 2 and 3.

The carriers prepared in this way are immersed in a 60 _° C. bath of an aqueous solution of 0.4% of one of the polymers listed in Table 1 under N1 to NV13. The residence time in the bath is 60 seconds. The excess solution is then removed with deionized water in a rinsing step and the carrier is air-dried.

Example B for the preparation of the reaction products (polymer-metal complexes)

0.2 mol, based on a phosphonic acid unit, of the polymer listed in Table 1 under N3 is dissolved in 600 ml of water. 0.2 mol of Co (NO ₃ ) ₂ dissolved in 200 ml of water are 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. The cobalt complex precipitates quantitatively as a tough, rubbery, violet-colored precipitate. This precipitate is filtered off, washed with water and then with methanol and dried at 60 _° C. in a drying cabinet; the excess Co ^{2 +} ions remain in the filtrate. In the same way, the polymers can also be reacted with other, at least divalent, metal cations.

The carrier materials described under A1 to A3, each treated with 13 different solutions, gave a total of 39 post-treated carriers. They are listed in Table 2 together with the measurement results explained below.

In addition to the immersion treatment described under A1 to A3, some carriers were subjected to an electrochemical aftertreatment, which is described below.

Example C for electrochemical treatment

Carriers from Example A2 are immersed in a 0.2% solution of preparations N1 to NV12 (Table 1) at 40 _° C. The carriers are switched as an anode and treated with direct current at 10 V for 20 seconds. The current drops from initially 3 A / dm ² to 0.2 A / dm ² during this treatment. The excess solution is then removed with deionized water in a rinsing step and the supports are air-dried. Table 3 lists the carriers thus produced and the results of the measurements described below.

The following measurements were carried out on each of the carrier materials obtained according to the examples:

Testing of the alkali resistance of the surface (according to US Pat. No. 3,940,321, columns 3 and 4, lines 29 to 68 and lines 1 to 8): The measure of the alkali resistance of an aluminum oxide layer is the dissolution rate of the layer in seconds in an alkaline zincate solution. The layer is more alkali-resistant the longer it takes to dissolve it. The layer thicknesses should be roughly comparable, since of course they also represent a parameter for the dissolution rate. A drop of a solution of 500 ml of distilled H ₂ O, 480 g of KOH and 80 g of zinc oxide is placed on the surface to be examined and the period of time until the appearance of metallic zinc is determined, which can be recognized by the blackening of the examination site. This "zinc certificate" is mentioned in column 4 of Table 2.

Testing the hydrophilicity of the carrier materials produced according to the invention

The test is carried out using wetting angle measurements against a drop of water. The angle is determined between the carrier surface and a tangent placed through the point of contact of the drop; it is generally between 0 _° and 90 _° . The smaller the angle, the better the wetting. The information in column 5 of Table 2 relates to these contact angle measurements.

Examples D for coating the support with light-sensitive materials

• 6,6 Gew.-Teile Kresol-Formaldehyd-Novolak (mit dem Erweichungsbereich 105_° - 120_°C nach DIN 53 181),
• 1,1 Gew.-Teile des 4-(2-Phenyl-prop-2-yl)-phenylesters der Naphthochinon-(1,2)-diazid-(2)-sulfonsäure-(4),
• 0,6 Gew.-Teile 2,2'-Bis-(naphthochinon-(1,2)-diazid-(2)-suifonyioxy-(5))-dinaphthyi-(1,1 ')-methan,
• 0,24 Gew.-Teile Naphthochinon-(1,2)-diazid-(2)-sulfochlorid-(4),
• 0,08 Gew.-Teile Kristallviolett,
• . 91,36 Gew.-Teile Lösemittelgemisch aus 4 Vol.-Teilen Ethylenglykolmonomethylether, 5 Vol.-Teilen Tetrahydrofuran und 1 Vol.-Teil Butylacetat.

D1: A piece of each of the carriers described in the carrier examples A1 to A3 is coated with the following solution:

• 6.6 parts by weight of cresol-formaldehyde novolak (with a softening range of 105 _° - 120 _° C according to DIN 53 181),
• 1.1 parts by weight of the 4- (2-phenyl-prop-2-yl) phenyl ester of naphthoquinone (1,2) diazide (2) sulfonic acid (4),
• 0.6 part by weight of 2,2'-bis (naphthoquinone- (1,2) -diazide- (2) -suifonyioxy- (5)) -dinaphthyi- (1,1 ') -methane,
• 0.24 part by weight of naphthoquinone- (1,2) -diazide- (2) -sulfochloride- (4),
• 0.08 part by weight of crystal violet,
• . 91.36 parts by weight of solvent mixture of 4 parts by volume of ethylene glycol monomethyl ether, 5 parts by volume of tetrahydrofuran and 1 part by volume of butyl acetate.

• 5,3 Gew.-Teile Natriummetasilikat x 9 H₂0
• 3,4 Gew.-Teile Trinatriumphosphat x 12 H₂0
• 0,3 Gew.-Teile Natriumdihydrogenphoshat (wasserfrei),
• 91,0 Gew.-Teile Wasser.

The coated supports are dried in the drying tunnel at temperatures up to 120 _° C. The printing plates thus produced are exposed under a positive template and developed with a developer of the following composition:

• 5.3 parts by weight of sodium metasilicate x 9 H ₂ 0
• 3.4 parts by weight of trisodium phosphate x 12 H ₂ 0
• 0.3 parts by weight of sodium dihydrogen phosphate (anhydrous),
• 91.0 parts by weight of water.

The printing forms obtained are assessed optically with regard to any dye residues (blue fog) still present in the non-image areas. The result is shown in column 6 of table 2.

• 16,75 Gew.-Teileneiner 8 %igen Lösung des Umsetzungsproduktes eines Polyvinylbutyrals mit einem Molekulargewicht von 70 000 bis 80 000, bestehend aus 71 Gew.-% Vinylbutyral-, 2 Gew.-% Vinylacetat- und 27 Gew.-% Vinylalkohol-Einheiten, mit Propenylsulfonylisocyanat.
• 2,14 Gew.-Teilen 2,6-Bis-(4-azido-benzal)-4-methyl-cyclohexanon,
• 0,23 Gew.-Teilen (^R)Rhodamin 6 GDN extra und
• 0,21 Gew.-Teilen 2-Benzoylmethylen-1-methyl-ß-naphthothiazolin in
• 100 Vol.-Teilen Ethylenglykolmonomethylether und
• 50 Vol.-Teilen Tetrahydrofuran

D2: A piece of each of the supports described in support examples A1 to A3 is provided with the following negative-working photosensitive layer:

• 16.75 parts by weight of an 8% solution of the reaction product of a polyvinyl butyral with a molecular weight of 70,000 to 80,000, consisting of 71% by weight of vinylbutyral, 2% by weight of vinyl acetate and 27% by weight of vinyl alcohol. Units, with propenylsulfonyl isocyanate.
• 2.14 parts by weight of 2,6-bis- (4-azido-benzal) -4-methyl-cyclohexanone,
• 0.23 parts by weight of ( ^R ) Rhodamine 6 GDN extra and
• 0.21 part by weight of 2-benzoylmethylene-1-methyl-ß-naphthothiazoline in
• 100 parts by volume of ethylene glycol monomethyl ether and
• 50 parts by volume of tetrahydrofuran

The carriers are dried as described under 3.

• 5 Gew.-Teile Natriumlaurylsulfat
• 1 Gew.-Teil Natriummetasilikat x 5 H₂O
• 94 Vol.-Teile Wasser

The dry layer weight is 0.75 g / m ^2. The reproduction layer is exposed under a negative original for 35 seconds with a metal halide lamp of 5 kW output. The exposed layer is made using a plush pad with a developer solution of the following composition

• 5 parts by weight of sodium lauryl sulfate
• 1 part by weight sodium metasilicate x 5 H ₂ O
• 94 parts by volume of water

developed.

The non-image areas of the printing forms obtained are assessed optically with regard to any remaining layers. The result of this assessment in comparison to the prior art (NV12) is shown in column 7 of table 2.

The characters in Table 2 mean

• - worse than the prior art of the comparative example of the NV12 solution
• o as good as the state of the art of the comparative example of solution NV12,
• + better than the prior art of the comparative example of the NV12 solution.

• 10 Gew.-Teile 2,5-Bis-(4'-diethylaminophenyl)-1,3,4-oxdiazol,
• 10 Gew.-Teile eines Mischpolymerisats aus Styrol und Maleinsäureanhydrid mit einem Erweichungspunkt von 210°C,
• 0,02 Gew.-Teile (^R)Rhodamin FB (C. I. 45 170),
• 300 Gew.-Teile Ethylenglykolmonomethylether.

D3: An anodized support prepared according to Example 15 in Table 2 is coated with the following solution to produce an electrophotographically operated offset printing plate:

• 10 parts by weight of 2,5-bis- (4'-diethylaminophenyl) -1,3,4-oxdiazole,
• 10 parts by weight of a copolymer of styrene and maleic anhydride with a softening point of 210 ° C.
• 0.02 part by weight ( ^R ) of Rhodamine FB (CI 45 170),
• 300 parts by weight of ethylene glycol monomethyl ether.

The carriers are dried as described under 3.

• 35 Gew.-Teilen Natriummetasilikat x 9 H₂0,
• 140 Vol.-Teilen Glycerin,
• 550 Vol.-Teilen Ethylenglykol und
• 140 Vol.-Teilen Ethanol

The layer is negatively charged to about 400 V in the dark by means of a corona. The charged plate is exposed imagewise in a repro camera and then developed with an electrophotographic suspension developer which also contains a dispersion of 3.0 parts by weight of magnesium sulfate in a solution of 7.5 parts by weight of pentaerythritol resin ester in 1200 parts by volume of an isoparaffin mixture represents a boiling range of 185 to 210 _° C. After removing the excess developer liquid, the developer is fixed and the plate is poured out into a solution for 60 seconds

• 35 parts by weight of sodium metasilicate x 9 H ₂ 0,
• 140 parts by volume of glycerin,
• 550 parts by volume of ethylene glycol and
• 140 parts by volume of ethanol

submerged. The plate is then rinsed off with a powerful jet of water, removing the areas of the photoconductor layer which are not covered with toner. The plate is then ready for printing. The non-image areas of the plate show good hydrophilicity and show no signs of attack even after exposure to alkaline solutions. Several tens of thousands of good prints can be achieved with the printing form.

Table 2 shows that the products according to the invention are better than the prior art in many properties, but not worse in none.

Table 3 shows that the electrochemically aftertreated supports have correspondingly good values as in Table 2, the values for the zincate test in particular being still improved. In addition to the tests described above, which were carried out with all supports, supports which had been prepared according to Examples 1 to 3 of Table 2, as described under D1, were coated with a positive-working photosensitive layer and printing forms were produced by exposure and development. With this, printing tests were undertaken which delivered up to 210,000 perfect prints. A printing form which was produced analogously with a carrier of comparative example NV12 (Table 2) showed poorer freewheeling behavior. After 170,000 prints, fine halftone dots were no longer reproduced correctly.

Claims (14)

1. A support material in the form of plates, sheets or webs for offset printing plates, composed of aluminum, which may have been pretreated, or its alloys, carrying on at least one side a hydrophilic coating of a phosphonic acid compound, wherein the hydrophilic coating comprises

a) a polymer of acrylamidoisobutylenephosphonic acid or

b) a copolymer of acrylamide and acrylamidoisobutylenephosphonic acid or

c) a salt of a) or b) with an at least divalent metal cation.

2. The support material as claimed in claim 1, wherein the acrylamide/acrylamidoisobutylenephosphonic acid monomer ratio of the copolymers of b) or c) is 1:99 to 99:1.

3. The support material as claimed in claim 2, wherein the monomer ratio is 3:97 to 90:10.

4. The support material as claimed in any of claims 1 to 3, wherein the metal cation of the coating c) is a V5+, Bi3+, AI3+, FE3+, Zr4+, Sn4+, Ca2+, Ba2+, Sr2+, Ti3+, Co2+, Fe2+, Mn2⁺, Ni2+, Cu2+. Zn2+ or Mg2+ ion.

5. The support material as claimed in any of claims 1 to 4, wherein the coating comprises mixtures of the products a) and/or b) and/or c).

6. The support material as claimed in any of claims 1 to 5, wherein the aluminum has been pickled.

7. The support material as claimed in any of claims 1 to 6, wherein the aluminum has been roughened.

8. The support material as claimed in any of claims 1 to 7, wherein the aluminum has been anodically oxidized.

9. The support material as claimed in any of claims 6 to 8, wherein the aluminum has a peak-to-valley height R_z of 3 to 10 µm.

10. The support material as claimed in claim 8 or 9, wherein the oxide layer of the aluminum is 0.3 to 3.0 µm thick.

11. A process for the preparation of a support material for offset printing plates as claimed in any of claims 1 to 10, which comprises coating the aluminum or its alloys with the dissolved products a) to c) or mixtures thereof in a concentration of 0.02 to 5.0% by weight in an aqueous solution, which may be acidic, by a dipping or electrochemical treatment and then drying the layer.

12. A process for the preparation of a support material as claimed in any of claims 1 to 10, which comprises, for the preparation of a coating c), treating the aluminum or its alloys first with a 0.01 to 10.0% solution of the polymers a) and/or b) and then with a 0.1% to saturated, preferably aqueous solution of a salt with the cations V5⁺, Bi3+, A13+, Fe3⁺, Zr4⁺, Sn4⁺, Ca2+, Ba2+, Sr2+, Ti3+, Co2+. Fe2+, M_n2+, Ni2+, CU2+, Zn2⁺, or Mg2⁺ ion and drying the layer produced from the reaction products.

13. The process for the preparation of a support material as claimed in claim 11 or 12, which comprises pickling and/or anodically oxidizing the aluminum or its alloys before the coating with the hydrophilic compound.

14. The use of a support material as claimed in any of claims 1 to 10 for coating with light-sensitive substances.