EP0069319B1 - Lithographic plate support materials with hydrophilic properties, processes for their manufacture and their use - Google Patents

Description

Hydrophilized substrates for offset printing plates, a process for their production and their use.

The invention relates to plate, film or ribbon-shaped support 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. 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 löslicher gewordenen 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 have become 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 great affinity for water, ie 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 by suitable operations such as. B. grain, matt chrome plating, surface oxidation and / or application of an intermediate layer in layer support 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 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.

In DE-PS907147 (= US-PS 2 714 066), DE-AS 14 71 707 (= US-PS 3 181 461 and US-PS 3 280 734) or DE-OS 25 32 769 (= US- PS 3 902 976) describes processes for the hydrophilization of printing plate support materials based on optionally anodized aluminum, in which these materials are treated with aqueous sodium silicate solution without or with the use of electric current.

From DE-PS 11 34 093 (= US-PS 3 276 868) and DE-PS 16 21 478 (= US-PS 4 153 461) it is known polyvinyl phosphonic acid or copolymers based on vinyl phosphonic acid, acrylic acid and vinyl acetate for the hydrophilization of printing plate support materials based on optionally anodized aluminum. 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-AS 13 00 415 (= US Pat. No. 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 area of application has also been described, for example.

DE-AS 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-AS 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-AS 11 73 917 (= GB-PS 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.

To produce a hydrophilic layer on printing plate support materials, according to DE-AS 1200847 (= US Pat. No. 3,232,783), a) an aqueous dispersion of a modified urea-formaldehyde resin, an alkylated methylol-melamine resin or a melamine resin Formaldehyde-polyalkylene polyamine resin applied, thereon b) an aqueous dispersion of a polyhydroxy or polycarboxy compound such as sodium carboxymethyl cellulose, and finally the base thus coated c) is treated with an aqueous solution of a Zr, Hf, Ti or Th salt.

DE-AS 1257170 (= US Pat. No. 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 vinylisilane units.

DE-OS 1471 706 (= US Pat. No. 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-PS 21 07 901 (= US Pat. No. 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.

According to DE-OS 22 11 553 (= US Pat. No. 3,900,370), a process is used to compact anodized aluminum surfaces in which a solution is used at a temperature of at least 90 ° C. and a pH of 5 to 6.5 is applied which contains water-soluble phosphonic acids which form complexes with divalent metals or their salts (such as 1-hydroxyethane-1,1-diphosphonic acid or aminotrimethylenephosphonic acid) and Ca ^{2 +} ions; these solutions can also contain dextrins.

DE-AS 23 05 231 (= GB-PS 1 414575) 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.

DE-OS 23 08 196 (= US Pat. No. 3,861,917) discloses hydrophilizing 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-A-2364 177 (= US Pat. No. 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.

This patent application also refers to polyacrylamide adhesive layers with zinc acetate as prior art, the weight ratio of zinc acetate to polyacrylamide being approximately 1: 1. At the same time, however, attention is drawn to the fact that such plates have a tendency to tone if they are not used immediately after production, which could also be demonstrated by the comparative example given there.

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.

The 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.

GB-PS 1 246696 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-OS 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-OS 28 07 396 (= US-PS 4 208 212),
• - Eisencyanid-Komplexe wie K_4[FE(CN)_6] oder Na₃[Fe(CN)₆] in Anwesenheit von Heteropolysäuren wie Phosphormolybdänsäure oder ihren Salzen und von Phosphaten nach der US-PS 3 769 043 oder
• - Eisencyanid-Komplexe in Anwesenheit von Phosphaten und Komplexbildnern wie Ethylendiamintetraessigsäure für elektrofotografische Druckplatten mit Zinkoxidoberfläche nach der NL-OS 68 09 658 (= US-PS 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-OS 28 07 396 (= US Pat. No. 4,208,212),
• - Iron cyanide complexes such as K _{4 [} FE (CN) _6] or Na ₃ [Fe (CN) ₆ ] in the presence of heteropolyacids such as phosphomolybdic acid or its salts and of phosphates according to US Pat. No. 3,769,043 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-OS 68 09 658 (= US Pat. No. 3,672,885).

• - So muß nach der Behandlung mit Alkalisilikaten, die zu guter Entwickelbarkeit und Hydrophilie führen, eine gewisse Verschlechterung der Lagefähigkeit von darauf aufgebrachten lichtempfindlichen Schichten hingenommen werden.
• - Die Komplexe der Übergangsmetalle begünstigen zwar prinzipiell die Hydrophilie von anodisch oxidierten Aluminiumoberflächen, sie haben jedoch den Nachteil, sehr leicht in Wasser löslich zu seinm so daß sie beim Entwickeln der Schicht mit wäßrigen Entwicklersystemenm die neuerdings in zunehmendem Maß Tenside und/oder Chelatbildner enthalten, die eine große Affinität zu diesen Metallen besitzen, leicht entfernt werden können. Dadurch wird die Konzentration der Ubergangsmetallkomplexe 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 Carbonsäuregruppen enthaltenden Polymeren macht sich negativ bemerkbar, daß freie Carboxylatfunktionen mit den Diazokationen von negativ arbeitenden lichtempfindlichen Schichten in Wechselwirkung treten können, so daß nach dem Entwickeln mit organische Lösemittel enthaltenden Entwicklern auf den Nichtbildstellen ein deutlicher Gelbschleier 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 (s. DE-AS 23 64 177), zu einer verminderten Schichthaftung, die sich beispielsweise darin äußern kann, daß beim Entwickeln Teile der Entwicklerflüssigkeit Bildstellen unterwandern.

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:

• - So after treatment with alkali silicates, which leads to good developability and hydrophilicity lead to a certain deterioration in the positionability of photosensitive layers applied thereon.
• 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 now increasingly contain surfactants and / or chelating agents, that 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 lead to a weakening of the hydrophilic effect.
• - In the treatment of carriers with water-soluble polymers, their good solubility, particularly in aqueous alkaline developers, such as are used predominantly for developing positive-working light-sensitive layers, also leads to a marked weakening of the hydrophilizing effect.
• - In the case of polymers containing carboxylic acid groups, it has a negative effect that free carboxylate functions can interact with the diazocations of negative-working photosensitive layers, so that after development with developers containing organic solvents, a clear yellow haze remains on the non-image areas 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, since the layer weights and thus the layer thickness is chosen to be relatively high (see DE-AS 23 64 177), to a reduced layer adhesion, which can be found therein, for example can express that parts of the developer liquid infiltrate image areas during development.

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 carboxylate, carboxamide and / or carboximide substituents as functional groups and b) a salt of an at least divalent metal cation and the amount of complex-type reaction product is less than 0.1 mg per dm2 of substrate surface. In 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 functions as a chelating ligand.

The water-soluble polymers used to prepare the complex reaction products are, in particular, polyacrylic acid, a copolymer based on polyacrylic acid, polyacrylamide, a copolymer based on polyacrylamide, a hydrolyzed or partially or completely subjected to ammonolysis with NH ₃ based on ethylene or vinyl methyl ether and maleic anhydride or carboxyalkyl cellulose (with alkyl groups from C ₁ to C ₃ , in particular carboxymethyl cellulose) or their mixed ethers such as carboxymethyl hydroxyethyl cellulose.

To prepare the complex reaction products, 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 V5 + -Bi3 + ^- , Al ^{3 + -} , Fe ^{3 + -} , Zr ^{4 + -} , Sn ^{4 + -} , Ca ^{2 + -} , Ba2 + ^- , Sr ^{2 + -} , Ti ^{3 + -} , Co ²⁺ -, Fe ^{2 + -} , Mn ^{2 + -} , Ni ^{2 + -} , C _u ^{2 + -} , Zn ^{2 + -} or Mg ^{2 + -} ions.

In the complex reaction products according to the invention, 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 predominantly water or completely filled with water. Depending on the metal cation, 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.

These complex 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. In the case of the copolymers containing maleic anhydride building blocks, higher temperatures (for example of more than 80 ° C.) are first required for the hydrolysis of the copolymers. 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 evident - depending on the used metal cation - in the immediately changing color of the solution or through precipitation. The driving force of these reactions is presumably the chelation effect (see, for example, FA Cotton and G. Wilkinson, “Inorganic Chemistry” 3rd edition, Verlag Chemie - Weinheim, 1974, pages 689/690). 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

• X = COO^e, M = Zentralion
• im Falle von 2-wertigen Metallkationen
• A = B = H₂0 oder
• im Falle von 3-wertigen Metallkationen
• A = H₂O und
• B = NO₃ ^-, CI-, HS0_4-, H₂P0₄₇, CH₃COO^-, OH- oder ähnliche Anionen

bedeuten. Im Falle von X = CONH₂ wird die Ladung des Zentralions M durch 2 bzw. 3 Liganden B abgesättigt.The chemical structure of the polymer-metal complexes according to the invention can be represented as follows:

being in particular

• X = COO ^e , 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 O and
• B = NO ₃ ^- , CI-, HS0 _4- , H ₂ P0 ₄₇ , CH ₃ COO ^- , OH- or similar anions

mean. In the case of X = CONH ₂ , the charge of the central ion M is saturated by 2 or 3 ligands B.

The structure given 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. In the following scheme, the range of variation of these exchange reactions is illustrated using the example of the Co ²⁺ complex of the ethylene / maleic acid copolymers:

This scheme does not claim to be complete, since in addition to the exchange reactions indicated, the metal salt anions still present in the reaction solution can also be incorporated into the coordination sphere of the metal ion or changes in the oxidation state of the metal ion can occur. Similar to the example of the Co2 + complex, all other complex reaction products according to the invention also react in a manner specific to the individual metal cation and / or complex.

For the treatment of the substrates for the production of the support materials for offset printing plates according to the invention, 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%, dissolved.

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 of 25 ° to 60 ° C. and residence times of 2 seconds to 10 minutes, preferably of 10 seconds to 3 minutes, have proven to be 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-step process. In the first step, 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. In the two-step treatment, the complex reaction products described above are formed on the substrate during the treatment. This variant of the method allows complex reaction products which are difficult to dissolve even in strongly acidic media to be applied to the substrate.

Determining the weight of the applied hydrophilic coating from the complex reaction product is problematic since even small amounts of the applied product show 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 .

To determine the layer weight, for example, an aluminum foil (e.g. made of electrochemically roughened and anodized aluminum with a thickness of 0.03 mm) can be weighed and then post-treated in the manner described above. After drying, weight increases in the range of approximately 4 to 8 mg / m ² (0.04 to 0.08 mg / dm ² ) are then determined, depending on the type of complex reaction product.

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 ≥ 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 ≥ 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 permissible. Additions of 0.5% Si, 0.5% Fe, 0.2% Ti, 0.2% Zn, 0.1% Cu and 0.15% other.

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. by 'AC treatment in aqueous HCI or HN0 ₃ solutions) roughened. 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 / l, 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 μm, in particular in the range from 4 to 8 μm.

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, which touch the roughness profile at the highest or lowest point within the Elnzel 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 ones Areas under it are the same.

• - Das Gleichstrom-Schwefelsäure-Verfahren, bei dem in einem wäßrigen Elektrolyten aus üblicherweise ca. 230 g H₂SO₄ pro 1 I 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 H₂S0₄/1) verringert oder auch auf 30 Gew.-% (365 g H₂SO₄/l) und mehr erhöht werden.
• - Die « Hartanodisierung wird mit einem wäßrigen, H₂S0₄ enthaltenden Elektrolyten einer Konzentration von 166 g H₂S0₄/1 (oder ca. 230 g H₂SO₄/l) 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 , H ₃ P0 ₄ , 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, BM Schenk, material aluminum and its anodic oxidation, Francke Verlag - Bern, 1948, page 760; Practical electroplating, Eugen G. Leuze Verlag - Saulgau, 1970, page 395 ff and pages 518/519; W. Hübner and CT Speiser, The practice of anodic oxidation of aluminum, Aluminum Verlag - Düsseldorf, 1977, 3rd edition, pages 137 ff):

• - The direct current sulfuric acid process, in which in an aqueous electrolyte from usually approx. 230 g H ₂ SO ₄ per 1 I solution at 10 ° to 22 ° C and a current density of 0.5 to 2.5 A / dm ² is anodized for 10 to 60 min. The sulfuric acid concentration in the aqueous electrolyte solution can also be reduced to 8 to 10 wt .-% H to ₂ S0 ₄ (100 g of H ₂ S0 _4/1), or even to 30 wt .-% (365 g H ₂ SO ₄ / l) and more can be increased.
• - The "hard-anodizing is with an aqueous H ₂ S0 ₄ electrolyte containing a concentration of 166 g H ₂ S0 _4/1 (or about 230 g H ₂ SO ₄ / l), 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 for 30 to 200 min.

In addition to the methods for anodic oxidation of. Printing plate carrier materials. For example, the following processes can also be used: the anodic oxidation of aluminum in an aqueous electrolyte containing H ₂ SO ₄ , the Al ³⁺ ion content of which is adjusted to values of more than 12 g / l (according to DE-OS 2811 396 = US-PS containing in an aqueous H ₂ S0 ₄ and H ₃ P0 ₄ electrolyte 4,211,619), (according to DE-OS 2,707,810 = US-PS 4 049 504) or in an aqueous H ₂ SO _4, H ₃ P0 ₄ and Al ^{3 + -} containing electrolytes (according to DE-OS 2 836 803 = US Pat ^. No. 4,229,226). 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 µm.

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.

In addition to the layers containing silver halides used in many fields, various others are also known, such as e.g. As described 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 polymerize, if appropriate by means of an initiator during exposure (Kosar, Chapter 5); and the layers containing o-diazo-quinones such as naphthoquinonediazides, p-diazo-quinones or diazonium salt condensates (Kosar, Chapter 7). Suitable layers also include the electrophotographic layers, i.e. H. those containing an inorganic or organic photoconductor. In addition to the light-sensitive substances, these layers can of course also other components such. B. contain resins, dyes or plasticizers. In particular, the following photosensitive 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-PS 854 890, 865 109, 879 203, 894 959, 938 233, 1 109 521, 1 144 705, 1 118 606, 1 120 273 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-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 2 024 244, 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 condensation with an active carbonyl compound in at least one position in an acid medium. D is a diazonium salt group attached to an aromatic carbon atom of A; n is an integer from 1 to 10; and B the remainder of a compound free of diazonium groups, which in acid Medium at at least one position of the molecule is capable of condensation with an active cabonyl compound.

Positive-working layers according to DE-OS 26 10 842, which contain a compound which splits off acid when irradiated, 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, if appropriate, 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. 2760863 and 3060023 and DE-OSes 20 64 079 and 23 61 041. As photoinitiators are u. a. Benzoin, benzoin ethers, multinuclear quinones, acridine derivatives, phenazine derivatives, quinoxaline derivatives, quinazoline derivatives or synergistic mixtures of different 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-OS 3 036 077, 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 can also be photoconductive layers such as z. B. in DE-PSen 11 17 391, 15 22 497, 15 72 312, 2322046 and 23 22 047 are described, applied to the support materials produced according to the invention, whereby highly light-sensitive, electrophotographic printing plates are formed.

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 support materials of which were treated according to the invention with the complex reaction products, are distinguished from those plates in which the same base material was treated with the corresponding polymers without a reaction with metal cations, by considerably improved hydrophilicity of the non-image areas and by an increased practical sensitivity to light ( better layer adhesion).

• - Durch die auch im getrockneten Zustand an das Metallion der Polymer-Metall-Komplexe gebundenen Wassermoleküle besitzen die erfindungsgemäß behandelten Druckformen in den Nichtbildstellen eine sehr gute Affinität zu Wasser (Hydrophilie). Daraus resultiert beim Druckvorgang eine gute farbabstoßende Wirkung, was zum schnellen Freilaufen der Platten in der Druckmaschine führt.
• - Aufgrund der Verankerung der Polymerketten in Kanälen und Poren des Aluminiumoxids sowie der zusätzlichen Wechselwirkung der Metallfunktionen mit dem Aluminiumoxid und der Unlöslichkeit der Polymer-Metall-Komplexe in organischen Lösemitteln, sowie in neutralen und alkalisch-wäßrigen Medien haften die erfindungsgemäß auf den Basisträger aufgebrachten Substanzen sehr gut auf dem Träger, so daß die ursprüngliche Polymer-Metall-Komplex-Konzentration auf dem Träger und somit die Hydrophilie des Trägers auch nach dem Entwicklungsvorgang und während des Druckvorgangs weitgehend erhalten bleibt. Dadurch wird das Auftreten von Tonerscheinungen während des Druckvorgangs und nach Maschinenstillständen weitgehend vermieden.
• - Durch Wechselwirkungen der Metallfunktionen der erfindungsgemäß auf den Basisträger aufgebrachten Polymer-Metall-Komplexe mit funktionellen Gruppen der anschließend aufgebrachten lichtempfindlichen Schichten wird eine erhöhte Haftung dieser Schichten auf dem Träger erzielt. Dies zeigt sich in der erhöhten praktischen Lichtempfindlichkeit von negativ arbeitenden Schichten, sowie in Steigerungen der Druckauflage bei allen Arten von verwendeten lichtempfindlichen Schichten.

It can be seen that the metal functions incorporated in the polymer have the following advantageous effects on the properties of lithographic plates:

• - Because the water molecules are bound to the metal ion of the polymer-metal complexes even in the dried state, the printing forms treated according to the invention have a very good affinity for water (hydrophilicity) in the non-image areas. This results in a good ink-repellent effect during the printing process, which leads to the free running of the plates in the printing press.
• - Due to the anchoring of the polymer chains in channels and pores of the aluminum oxide and the additional interaction of the metal functions with the aluminum oxide and the insolubility of the polymer-metal complexes in organic solvents, as well as in neutral and alkaline aqueous media, the substances applied to the base support according to the invention adhere very good on the support, so that the original polymer-metal complex concentration on the support and thus the hydrophilicity of the support is largely retained even after the development process and during the printing process. This largely prevents the appearance of toner during the printing process and after machine downtimes.
• - Interaction of the metal functions of the polymer-metal complexes applied to the base support in accordance with the invention with functional groups of the subsequently applied light-sensitive layers results in increased adhesion of these layers to the support. This is reflected in the increased practical photosensitivity of negatively working layers, as well as in increases in the print run for all types of photosensitive layers used.

In the above description and the following examples,% data always mean% by weight, unless stated otherwise. Parts by weight relate to parts by volume in the ratio of g to cm ³ . The following methods for determining parameters were also used in the examples.

The hydrophilicity of the carrier materials produced according to the invention is tested using wetting angle measurements in relation to a drop of water placed on it, the angle between the carrier surface and a tangent through the point of contact of the drop being determined, it is generally between 0 and 90 degrees. The smaller the angle, the better the wetting.

Testing 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 rate at which the layer dissolves in an alkaline zincate solution is used as a measure of the alkali resistance of an aluminum oxide layer. The layer is the more alkali-resistant the longer it is used Resolution needs. 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.

Production of complex reaction products (polymer-metal complexes) example 1

0.2 mol, based on a vinyl methyl ether maleic anhydride unit, of the copolymer of vinyl methyl ether and maleic anhydride is dissolved in 600 ml of water at 85 ° to 100 ° C. The anhydride groups are hydrolyzed to the free acids. 0.2 mol of Co (NOg) 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. After the reaction solution has cooled to room temperature, it is neutralized by slowly adding dilute aqueous NaOH solution, during which the cobalt complex precipitates quantitatively as a viscous, rubbery pink-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, other polymers containing maleic anhydride units can be reacted with at least divalent metal cations.

Example 2

To produce further polymer-metal complexes, the copolymer used in Example 1 is dissolved in dilute aqueous NH ₃ solution, the maleic anhydride functions being hydrolyzed to amide or half-amide groups. The further reaction with the metal cation is carried out according to Example 1.

Example 3

To prepare the polymer-metal complexes of polyacrylic acid or polyacrylamide, the procedure according to Example 1 is followed, with only the first hydrolysis step being omitted; H. working at 25 ° C.

Production of offset printing plates Example 4

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 R _z value of 6 μm being obtained. The subsequent anodic oxidation is carried out in accordance with the process described in DE-OS 2811 396 in an electrolyte containing sulfuric acid; the oxide weight is 3.0 g / m ² .

The aluminum strip prepared in this way is then passed through a bath heated to 60 ° C. from a 0.5% solution (in 2% H ₃ PO ₄ ) of the polymer-metal complex composed of the copolymer of vinyl methyl ether and maleic anhydride and Al ^{3 + -} ion guided. The residence time in the bath is 20 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.

• 0,7 Gew.-Teile des Polykondensationsproduktes aus 1 Mol 3-Methoxy-diphenylamin-4-diazo- niumsulfat und 1 Mol 4,4'-Bis-methoxymethyl-diphenylether, ausgefällt als Mesitylensulfonat,
• 3,4 Gew.-Teile 85 %ige Phosphorsäure,
• 3,0 Gew.-Teile eines modifizierten Epoxidharzes, erhalten durch Umsetzen von 50 Gew.-Teilen eines Epoxidharzes mit einem Molgewicht unterhalb 1 000 und 12,8 Gew.-Teilen Benzoesäure in Ethylenglykolmonomethylether in Gegenwart von Benzyltrimethylammoniumhydroxid,
• 0,44 Gew.-Teile feingemahlenes Heliogenblau G (C. I. 74 100),
• 62,0 Vol.-Teile Ethylenglykolmonomethylether,
• 30,6 Vol.-Teile Tetrahydrofuran und
• 8.0 Vol.-Teile Ethylenglykolmethyletheracetat.

To produce lithographic printing plates, this support is coated with the following solution and dried:

• 0.7 part by weight of the polycondensation product of 1 mol of 3-methoxy-diphenylamine-4-diazo-niumsulfate and 1 mol of 4,4'-bis-methoxymethyl-diphenyl ether, precipitated as mesitylene sulfonate,
• 3.4 parts by weight of 85% phosphoric acid,
• 3.0 parts by weight of a modified epoxy resin obtained by reacting 50 parts by weight of an epoxy resin with a molecular weight below 1,000 and 12.8 parts by weight of benzoic acid in ethylene glycol monomethyl ether in the presence of benzyltrimethylammonium hydroxide,
• 0.44 part by weight of finely ground heliogen blue G (CI 74 100),
• 62.0 parts by volume of ethylene glycol monomethyl ether,
• 30.6 parts by volume of tetrahydrofuran and
• 8.0 parts by volume of ethylene glycol methyl ether acetate.

After exposure through a negative mask, a solution of

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 18 ° for the stripped material, the print run was 200,000.

Example 5

• 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),

An aluminum strip treated in accordance with Example 4 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),

The coated tape is 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:

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.

Examples 6 to 24 and comparative examples V 1 to V 6

• 1) Die Ausprüfung der Entwickelbarkeit wurde anhand der in den Beispielen 4 und 5 eingesetzten lichtempfindlichen Schichten (B 4 bzw. B 5) durchgeführt.
• 2) Die Auswertung der Spalten « Entwickelbarkeit und « farbabstoßende Wirkung » wurde im Vergleich zu dem als Stand der Technik geltenden Beispiel V 6 (gemäß DE-PS 1 621 478) durchgeführt. Dabei bedeuten :
  
  

An electrochemically roughened and anodized aluminum sheet according to Example 4 is immersed for 30 seconds at room temperature in one of the phosphoric acid polymer-metal complex solutions (0.5%) listed below, dried and a sample with the light-sensitive layer from Example 4 and a sample coated with the light-sensitive layer from Example 5. The results of the carrier tests (wetting angle measurement against water, zinc acetate test) and of the copy are compiled in the following table in comparison to samples which were treated with the unreacted starting polymers. The print runs of the plates produced according to the examples according to the invention correspond to the runs of comparative example V 6. In the table:

• 1) The developability was tested on the basis of the light-sensitive layers used in Examples 4 and 5 (B 4 and B 5, respectively).
• 2) The evaluation of the columns “Developability and“ Ink-repelling effect ”was carried out in comparison to Example V 6, which is considered to be state of the art (according to DE-PS 1 621 478). Mean:
  
  

(See table on page 12 ff.) Example 25

An electrochemically roughened flat (R _z = 3 μm) and anodized aluminum sheet is aftertreated and coated in accordance with Example 13. The printing plates produced in this way are distinguished by the same advantages as indicated in Example 13.

Example 26

An aluminum support, which is roughened by brushing with an aqueous abrasive suspension, is after-treated according to Example 23 and coated with the following solution:

The development is done with the following solution:

With the same copying properties, as on a carrier treated according to DE-PS 11 34093 with polyvinylphosphonic acid. The printing form thus produced is characterized by a significantly improved ink-repelling effect of the non-image areas.

Example 27

An aluminum sheet treated according to Example 4 is coated with the following solution:

getaucht. Die Platte wird dann mit einem kräftigen Wasserstrahl abgespült, wobei die nicht mit Toner bedeckten Stellen der Photoleiterschicht entfernt werden. Die Platte ist dann druckfertig. Die so hergestellte Flachdruckform besitzt in den Nichtbildbereichen eine sehr gute farbabstoßende Wirkung.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 is obtained by dispersing 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 with a boiling range of 185 to 2.10 ° C was obtained. After removing the excess developer liquid, the plate is poured out into a solution for 60 seconds

submerged. The plate is then rinsed off with a powerful jet of water, removing the areas of the photoconductor layer not covered with toner. The plate is then ready for printing. The planographic printing plate thus produced has a very good ink-repellent effect in the non-image areas.

Example 28

An aluminum strip produced according to Example 18 is made with a solution

beschichtet. Das Trockengewicht beträgt 0,75 g/m².26.75 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 propenyl sulfonyl isocyanate.

coated. The dry weight is 0.75 g / m ² .

behandelt, wobei die Nichtbildstellen entfernt werden. Die freigelegten Trägerflächen besitzen einer sehr gute farbabstoßende Wirkung, was sich im schnellen Freilaufen der Druckplatte in der Druckmaschine manifestiert. Die Auflagenleistung der Platte in einer Bogenoffsetmaschine beträgt 170 000 Bogen.The light-sensitive layer is exposed under a negative original for 35 seconds using a metal halide lamp with a power of 5 kW. The exposed layer is made using a plush pad with a developer solution of the following composition.

treated, the non-image areas are removed. The exposed carrier surfaces have a very good ink-repellent effect, which is manifested in the fast free running of the printing plate in the printing press. The circulation of the plate in a sheetfed offset press is 170,000 sheets.

Example 29

An aluminum sheet which had been electrochemically roughened and anodically oxidized according to Example 4 was immersed for 30 seconds at 65 ° C. in a 1% strength aqueous solution of the copolymer of ethylene and maleic anhydride hydrolyzed at 80 ° C. When the substrate is removed from the bath, the excess solution is scraped off the surface. Subsequently, the still moist substrate is immersed in a 2% aqueous solution of Al (NO ₃ ) ₃ .9H ₂ 0 for 30 seconds 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 5, exposed and developed. The properties of the printing plate produced in this way correspond to that of a material produced according to Example 5.

Claims (13)

1. A plate-, foil- or strip-shape support material for offset printing plates, which material is based on chemically, mechanically and/or electrochemically grained aluminum or on one of its alloys, which optionally has an aluminum oxide layer produced by anodic oxidation, and which material has a hydrophilic coating of at least one hydrophilic organic polymer on at least one surface of the support material, wherein the salt-type hydrophilic organic polymer is a complex product obtained from reacting a) a water-soluble organic polymer - except for cellulose ethers - having carboxylate substituents, carboxylic acid amide substituents and/or carboxylic acid imide substituents as functional groups, with b) a salt of an at least divalent metal cation, and the quantity of the complex reaction product per 1 dm² of support material surface is less than 0.1 mg.

2. The support material for offset printing plates as claimed in claim 1, wherein one to three coordination sites of the metal cation are occupied by the functional groups of the polymer.

3. The support material for offset printing plates as claimed in claim 1 or 2, wherein the water-soluble organic polymer is polyacrylic acid ; a copolymer based on polyacrylic acid ; polyacrylamide ; a copolymer based on polyacrylamide ; a hydrolysed copolymer based on ethylene or vinylmethyl ether and maleic acid anhydride ; a copolymer which has been partly or completely subjected to an ammonolysis with NH₃ and is based on ethylene or vinylmethyl ether and maleic acid anhydride ; ore one of the salts of these polymers with a monovalent cation.

4. The support material for offset printing plates, as claimed in any of claims 1 to 3, wherein the metal cation is di-, tri- or tetravalent.

5. The support material for offset printing plates as claimed in any of claims 1 to 4, wherein the metal cation is a Bi3+, AI³⁺, Fe³⁺, Zr⁴⁺, Sn⁴⁺, Ca2+, Ba2+, Sr²⁺, Ti3+, C₀ ²⁺, Fe²⁺, Mn²⁺, Ni2⁺, Cu2+, Zn²⁺ or Mg²⁺ ion.

6. A process for manufacturing the support material for offset printing plates, as claimed in any of claims 1 to 5, which comprises applying a solution of the complex reaction product in aqueous acids to at least one surface of the support material, rinsing with water, and drying the support material thus modified.

7. The process as claimed in claim 6, wherein the complex reaction product is dissolved in a concentration of 0.05 to 5 % by weight in 0.1 to 10 % by weight strength aqueous acids.

8. The process as claimed in claim 6 or 7, wherein the complex reaction product is dissolved in a concentration of 0.1 to 1 % by weight in 0.5 to 3 % by weight strength aqueous acids.

9. The process as claimed in any of claims 6 to 8, wherein the acid used is phosphoric acid.

10. A process for manufacturing the support material for offset printing plates as claimed in any of claims 1 to 5, wherein the complex reaction product of the components a) and b) is formed on the support material, followed by rinsing with water.

11. The process as claimed in claim 10, which comprises dipping the support material in subsequent steps in an aqueous solution of component a) and an aqueous solution of component b).

12. The process as claimed in claim 11, wherein the first aqueous solution contains from 0.2 to 10 % by weight of component a) and the second aqueous solution contains from 0.1 % by weight to the point of saturation of component b).

13. The use of the support material as claimed in any of claims 1 to 5, in the preparation of offset printing plates having a light-sensitive layer.