EP0468313A1 - Plate-, foil- and web-shaped support material for offset printing plates, process for its production and use thereof - Google Patents

Abstract

The invention relates to a support material based on aluminium which bears a hydrophilic coating which consists of a copolymer of a monomer carrying basic groups with a monomer which carries acidic groups and optionally a monomer having neutral groups or salts of the copolymer with a metal cation which is at least divalent. The material which has been rendered hydrophilic serves as a support for photosensitive substances for the production of printing plates.

Description

The invention relates to plate, film or tape-shaped carrier material for offset printing plates, consisting of pretreated aluminum or one of its alloys, which has a hydrophilic coating of a polymer containing acid side groups on at least one side, a process for producing a carrier material and the use of a carrier material .

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 löslicheren Teile der lichtempfindlichen Schicht müssen durch eine Entwicklung leicht zur Erzeugung der hydrophilen Nichtbildstellen rückstandsfrei vom Träger zu entfernen sein.
• - Der an 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 druckende Teil der Schicht nach der Belichtung muß in einem ausreichenden Maß gegeben sein, um eine hohe Druckauflage zu garantieren.

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 at 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 part of the layer after exposure must be sufficient to guarantee a high print run.

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 processing measures, e.g. Grain, matt chrome plating, surface oxidation and / or application of an intermediate layer, transferred 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 such as dry brushing, wet brushing, sandblasting, chemical and / or electrochemical treatment or a combination thereof. 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 der DE-C 907 147 (= US-A 2,714,066), der DE-B 14 71 707 (= US-A 3,181,461 und US-A 3,280,734) oder der DE-A 25 32 769 (= US-A 3,902,976) werden Verfahren zur Hydrophilierung von Druckplattenträgermaterialien auf der Basis von gegebenenfalls anodisch oxidiertem Aluminium beschrieben, in denen diese Materialien ohne oder mit Einsatz von elektrischem Strom mit wäßriger Natriumsilikat-Lösung behandelt werden.

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-A 3,902,976) Process 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-A 11 34 093 (= US-A 3,276,868) and DE-C 16 21 478 (= US-A 4,153,461) it is known to use polyvinylphosphonic acid or copolymers based on vinylphosphonic acid, acrylic acid and vinyl acetate for the hydrophilization of printing plate support materials to be used on the basis of 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-B 13 00 415 (= US-A 3,440,050) also leads to additional hydrophilization of aluminum oxide layers on printing plate support materials.

• In der DE-B 10 56 931 wird der Einsatz von wasserlöslichen, linearen Mischpolymeren auf der Basis von Alkyl-vinylethern und Maleinsäureanhydriden in lichtempfindlichen Schichten für Druckplatten beschrieben. Besonders hydrophil sind von diesen Mischpolymeren solche, bei denen die Maleinsäureanhydridkomponente nicht oder mehr oder weniger vollständig mit Ammoniak, einem Alkalihydroxid oder einem Alkohol zur Reaktion gebracht wurde.

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-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 cured in a water-insoluble state on the metal support.

According to DE-B 12 00 847 (= US-A 3,232,783), a) an aqueous dispersion of a modified urea-formaldehyde resin, an alkylated methylol-melamine resin or a melamine-formaldehyde is firstly used to produce a hydrophilic layer on printing plate support materials -Polyalkylenpolyamin-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-B 12 57 170 (= 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 vinylsilane units.

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

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) 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-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 in order 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 made from 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.

EP-B 0 149 490 describes compounds for hydrophilization which, in addition to amino groups, additionally contain carboxyl or carboxylate groups, sulfo groups or hydroxyl groups, is based on monomers and describes a molecular weight of 1000 as the upper limit.

• - 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 K₄(Fe(CN)₆) oder Na₃(Fe(CN)₆) 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 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) 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 and 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 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.

DE-A 26 15 075 (= GB-A 1,495,895) 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.

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, und die Auflage einer so nachbehandelten Druckplatte sinkt drastisch.
• - Die Komplexe der Übergangsmetalle 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 ohne Verankerungsmöglichkeiten 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.
• - Monomere, hydrophile Verbindungen, wie z.B. in der EP-B 149 490 beschrieben, haben ganz allgemein den Nachteil, daß sie während des Entwicklungs- bzw. Druckprozesses relativ schnell von der freigelegten Nichtbildstellenoberfläche weggewaschen werden und ihre hydrophile Wirkung verlieren, da nicht genügend Verankerungsstellen in der Oberfläche gegeben sind.
• - 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 werden (siehe DE-B 23 64 177), zu einer verminderten Kopierschichthaftung, 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 with regard to developer strength, water flow, free-running behavior and resistance to contact:

• - After the treatment with alkali silicates, which lead to good developability and hydrophilicity, a certain deterioration in the shelf life of the photosensitive layers applied thereon has to be accepted, and the support of such a post-treated printing plate drops drastically.
• - The complexes of the transition metals favor the hydrophilicity of anodized aluminum surfaces in principle, but they have the disadvantage of being very easily soluble in water, so that when developing the layer with aqueous developer systems, they are increasingly used as 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 lead to a weakening of the hydrophilic effect.
• - In the treatment of supports with water-soluble polymers without anchoring options, their good solubility, particularly in aqueous alkaline developers, as they are mainly used for developing positive-working light-sensitive layers, also leads to a marked weakening of the hydrophilizing effect.
• Monomeric, hydrophilic compounds, as described, for example, in EP-B 149 490, have the general disadvantage that they are washed away relatively quickly from the exposed non-image area surface during the development or printing process and lose their hydrophilic effect since insufficient anchorage points are given in the surface.
• - 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 copy layer adhesion, for example because the layer weights and thus the layer thickness are chosen to be relatively high (see DE-B 23 64 177) can express that parts of the developer liquid infiltrate image areas during development.

The object of the invention is therefore to produce support materials for offset printing plates with good hydrophilization properties, which are suitable as supports for positive, negative or electrophotographic photosensitive layers without reducing their shelf life, reactions between the hydrophilizing agent and the photosensitive layer or reducing the layer adhesion becomes.

The invention is based on a plate, film or tape-shaped carrier material for offset printing plates, consisting of mechanically, chemically or electrochemically roughened and optionally anodized aluminum or one of its alloys, which has a hydrophilic coating of a polymer containing acid side groups on at least one side.

The solution to the problem is that the hydrophilic polymer with repeating units contains, in addition to the acidic side groups, basic groups capable of protonation.

The further development of the carrier material results from the features of claims 2 to 19.

The mixed polymer consists of at least 2 mol% of units with a basic side group, optionally nonionic units, and at least 2 mol% of units with an acidic side group capable of salt formation - preferably with a divalent or higher-valent metal cation.

Suitable monomer units with basic side groups are compounds which contain aliphatic or aromatic amino groups, in particular tertiary amino groups, for example dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate and vinylpyridine.

Vinyl compounds can be used as non-ionic components, e.g. Acrylic acid esters such as ethyl, propyl, butyl, hexyl and decyl acrylate as well as the corresponding methacrylic acid esters and styrene, isoprene and butadiene.

The acidic components include Carboxylic, sulfonic and phosphonic acids, e.g. Acrylic, methacrylic, vinylphosphonic, vinylsulfonic, maleic, itaconic, vinylbenzoic, vinylnaphthoeic, vinylphenylsulfonic, vinylphenylphosphonic and cinnamic acids.

The ratio of the monomer units can be varied within a wide range. For example, the molar ratios of the acidic to the basic monomer units can be varied from 2:98 to 98: 2. However, a ratio of about 1: 1 (equimolar) is particularly preferred. For this purpose, non-ionic, neutral groups can also be used in the copolymer to adjust the solubility.

The acidic groups ensure good adhesion to the (anodized) aluminum substrate; The basic groups effect an additional hydrophilization of the non-image areas and an improvement in adhesion by interaction with layer components in the image areas in the acidic wash water. Because the groups are anchored to a polymer structure, there are numerous anchoring points to the layer and to the support, and the risk of a loss of effectiveness during the printing process is greatly reduced. The average molecular weight is at least 1,000, preferably between 5,000 and 50,000, but polymers with an even higher average molecular weight than 50,000 can also be used with technical advantage. The copolymers are preferably dissolved in water with the addition of acids or alkalis, so that a pH between 1 and 13, preferably between 3 and 10, is set. The compounds described can also be used in the form of their metal or ammonium salts, the salts of divalent and higher-valent metals being particularly preferred.

To prepare metal salts of the copolymers, 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 of the coating are in particular V5 + Bi ³⁺ -, A1 ³⁺ -, Fe ³⁺ -, Zr ⁴⁺ -, Sn ⁴⁺ - Ca ²⁺ -, Ba ²⁺ -, Sr ²⁺ -, Ti ³⁺ -, Co ²⁺ -, Fe ²⁺ -, Mn ²⁺ -, Ni ²⁺ -, Cu ²⁺ -, Ce ⁴⁺ -, Z _n ^{2 + -} 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, dissolved in water or, if necessary, dissolved in dilute mineral acid, is slowly added dropwise to the aqueous polymer solution. This leads to the immediate conversion of the reaction components to the previously described products. The rapid onset of the reaction can - depending on the metal cation used - be shown by the color change of the solution occurring immediately or by 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.

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 0.001 to 10%, preferably in concentrations of 0.1 to 1%.

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 from 20 to 95 ° C., preferably from 40 to 80 ° C., and residence times from 1 s to 10 min, preferably from 2 s to 1 min, 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 substrate treated in this way is then expediently dried at from 110 to 130.degree. The pH is adjusted between 1 to 13, preferably to a pH of 3 to 10, and in particular to a value of 4 to 8.

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 because 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 clearly below 1 mg / dm ² , in particular below 0.8 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 Hr. 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, 0,02 % 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 Mr. 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 admissible admixtures of 0.5% Si, 0.5% Fe, 0.2% Ti, 0.02% 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. 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 / I, the current density between 15 and 130 A / dm ² , the dwell time between 10 and 100 s and the electrolyte flow rate on the surface of the workpiece to be treated between 5 and 100 cm / s; 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 2 to 7 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 so 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 H2 S04 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/1 H₂S0₄ (oder ca. 230 g/I 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 SO ₄ , H ₃ PO ₄ , H ₂ C ₂ O ₄ , amidosulfonic acid, sulfosuccinic acid, sulfosalicylic acid or mixtures thereof, can be used for the 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 - 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 usually from about 230 g H2 S04 per 1 liter of solution at 10 to 22 ° C and a current density of 0.5 to 2.5 A / dm ² for 10 to Is anodized for 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 H ₂ S0 _4- containing electrolyte with a concentration of 166 g / 1 H ₂ S0 ₄ (or approx. 230 g / IH ₂ S0 ₄ ) at an operating temperature of 0 to 5 C, at a current density from 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 processes for the anodic oxidation of printing plate support materials already mentioned in the previous paragraph, the following processes can also be used, for example: the anodic oxidation of aluminum in an aqueous electrolyte containing H ₂ S0 ₄ , the Al ³⁺ - ion content is set to values of more than 12 g / l (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 and A1 ³ 'ions (according to DE-A 28 36 803 = US-A 4,229,226).

Direct current is preferably used for the anodic oxidation, however alternating current or a combination of these types of current (for example 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.

• positiv arbeitende, o-Chinondiazid-, bevorzugt o-Naphthochinondiazid-Verbindungen, die beispielsweise in den DE-C 854 890, 865 109, 879 203, 894 959, 938 233, 1 109 521, 1 144 705, 1 118 606, 1 120 273 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, 1 138 399, 1 138 400, 1 138 401, 1 142 871, 1 154 123, 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, die eine bei Bestrahlung Säure abspaltende Verbindung, eine Verbindung, die mindestens eine durch Säure abspaltbare C-O-C-Gruppe aufweist (z.B. eine Orthocarbonsäureestergruppe, eine Carbonsäureamidacetalgruppe oder eine Acetalgruppe) und gegebenenfalls ein Bindemittel enthalten; negativ arbeitende Schichten aus photopolymerisierbaren Monomeren, Photoinitiatoren, Bindemitteln und gegebenenfalls weiteren Zusätzen. Als Monomeren werden dabei beispielsweise Acryl- und Methacrylsäureester oder Umsetzungsprodukte von Di-isocyanaten mit Partialestern mehrwertiger Alkohole eingesetzt, wie es beispielsweise in den US-A 2,670,863 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 Polymeren 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 5); and the layers containing o-diazoquinones, such as naphthoquinonediazides, p-diazoquinones 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, 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-C 596 731, 1 138 399, 1 138 400, 1 138 401, 1 142 871, 1 154 123 US-A 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 residue of a diazonium group-free compound capable of condensing with an active carbonyl compound in at least one position of the molecule in an acid medium;
• positive working layers which contain a compound which releases acid upon irradiation, a compound which has at least one COC group which can be split off by acid (for example an orthocarboxylic acid ester group, a carboxamide amide acetal group or an 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 di-isocyanates with partial esters of polyhydric alcohols, as described, for example, in US Pat. Nos. 2,670,863 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, for example polyamides, polyesters, alkyd resins, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide, gelatin or cellulose ethers;
• Negative working layers according to DE-A 30 36 077, which contain a diazonium salt polycondensation product or an organic azido compound as the photosensitive compound and a high molecular weight polymer with pendant alkenylsulfonyl or cycloalkenylsulfonylurethane groups as the 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, are applied to the support materials, whereby highly light-sensitive, electrophotographic layers 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 carrier materials of which have been treated according to the invention, show a significantly lower color haze and improved hydrophilicity compared to those plates which have been treated with high polymer acrylic acid, with polymeric vinylphosphonic acid or only with hot water. The adhesion of the light-sensitive layer to the surface of the support was also better in the samples treated according to the invention than in the comparison samples.

Examples for the production of a roughened and anodized printing plate carrier

• 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 around 50 to 70 ° C. The electrochemical roughening of the aluminum surface takes place with alternating current and in an electrolyte containing HN0 ₃ ; a surface roughness with an R _z value of 6 _μm 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 by the number 1 in Tables 2 and 3. The aluminum strip prepared in this way is then passed through a bath at 60 ° C. from a 0.5% solution, which is one of the polymers according to the invention or one of the comparison substances (A to C), which is brought to a pH with H ₃ PO ₄ or NaOH. Value from 5 to 6 were set. The compositions of these solutions are listed in Table 1. The dwell time in the bath is 30 s. 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 R _z value of 6 μm 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 is one of the polymers according to the invention or one of the comparison substances (A to C), which is brought to a pH with H ₃ PO ₄ or NaOH. Value between 5 and 6 were set. 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. Then the carrier is brushed using cutting granules. A surface roughness with an R _z value of 4 _μm is obtained. The subsequent anodic oxidation is carried out according to the process described in DE-C 16 71 614 (= = US-A 3,511,661) in an electrolyte containing phosphoric acid. The oxide weight is 0.9 g / m ^2. The aluminum strip processed in this way is cut into sheets 50 x 45 cm in size. A carrier produced in this way is designated in Table 2 with the number 3. The carriers prepared in this way are placed in a 60 ° C. bath of an aqueous solution of 0.4% of one of the aftertreatment agents listed in Table 1 under A to N, which is adjusted to a pH between 5 and 6 using H ₃ PO ₄ or NaOH was submerged. The dwell time in the bath is 60 s. The excess solution is then removed with deionized water in a rinsing step and the carrier is air-dried.
  
  

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.

Instead of the immersion treatment described under AI to A3, some carriers were subjected to an electrochemical aftertreatment, which is described below.

Electrochemical treatment

Carriers from Example A2 are immersed in a 0.2% solution of preparations A to N (Table 1) at 40 ° C. The carriers are switched as an anode and treated with 10 volt direct current for 20 s. The excess solution is then removed with deionized water in a rinsing step and the supports are air-dried. Table 3 shows the supports 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 the alkali resistance of the surface

The dissolution rate of the layer in an alkaline zincate solution in seconds is a measure of the alkali resistance of an aluminum oxide layer. 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. This method is described, for example, in US Pat. No. 3,940,321, columns 3 and 4, lines 29 to 68 and lines 1 to 8.

Testing the hydrophilicity of the carrier materials

The test is carried out using wetting angle measurements against a drop of water. The angle is determined between the carrier surface under the drop 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.

Coating the supports with light-sensitive materials:

• 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 to 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) -sulfonyloxy- (5)) -dinaphthyl- (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 Natriumdihydrogenphosphat (wasserfrei)
• 91,0 Gew.-Teile Wasser.

The coated substrates are dried in the dryer 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.

• D2: Ein Stück eines jeden der in den Träger-Beispielen A1 bis A3 beschriebenen Träger wird mit der folgenden negativ arbeitenden lichtempfindlichen Schicht versehen:
• 16,75 Gew.-Teile einer 8%igen Losung 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.-Teile 2,6-Bis-(4-azido-benzal)-4-methylcyclohexanon,
• 0,23 Gew.-Teile (^R)Rhodamin 6 GDN extra und
• 0,21 Gew.-Teile 2-Benzoylmethylen-1-methyl-ß-naphthothiazolin in
• 100 Vol.-Teile Ethylenglykolmonomethylether und
• 50 Vol.-Teile Tetrahydrofuran

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.

• 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 propenyl sulfonyl isocyanate.
• 2.14 parts by weight of 2,6-bis- (4-azido-benzal) -4-methylcyclohexanone,
• 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 point D1.

• 5 Gew.-Teile Natriumlaurylsulfat
• 1 Gew.-Teil Natriummetasilikat x 5 H₂0
• 94 Vol.-Teile Wasser
• entwickelt.

The dry layer weight is 0.75 g / m ^2. The reproduction layer is exposed under a negative original for 35 s with 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

• 5 parts by weight of sodium lauryl sulfate
• 1 part by weight of sodium metasilicate x 5 H ₂ 0
• 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 (A) is in column 7 of Table 2.

• - schlechter als der Stand der Technik gemäß dem Vergleichsbeispiel der Lösung A
• o gleich gut wie der Stand der Technik gemäß dem Vergleichsbeispiel der Lösung A
• + besser als der Stand der Technik gemäß dem Vergleichsbeispiel der Lösung A.
• D3: Ein gemäß Beispiel 15 der Tabelle 2 hergestellter, anodisch oxidierter Träger wird zur

The characters in Table 2 mean

• - worse than the prior art according to the comparative example of solution A.
• o as good as the prior art according to the comparative example of solution A.
• + better than the prior art according to the comparative example of solution A.
• D3: An anodized support prepared according to Example 15 in Table 2 becomes

• 10 Gew.-Teile 2,5-Bis-(4'-diethylaminophenyl)-1,3,4-oxadiazol,
• 10 Gew.-Teile eines Mischpolymerisats aus Styrol und Maleinsäureanhydrid mit einem Erweichungspunkt von 210 C,
• 0,02 Gew.-Teile ^(R)Rhodamin FB (C.1.45 170),
• 300 Gew.-Teile Ethylenglykolmonomethylether

Production of an electrophotographic offset printing plate coated with the following solution:

• 10 parts by weight of 2,5-bis- (4'-diethylaminophenyl) -1,3,4-oxadiazole,
• 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 (C.1.45 170),
• 300 parts by weight of ethylene glycol monomethyl ether

The carriers are dried as described under point D1.

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

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 Nichtbildstellen der Platte zeigen eine gute Hydrophilie und lassen auch nach der Einwirkung alkalischer Lösungen keine Zeichen eines Angriffs erkennen. Es lassen sich mit der Druckform mehrere zehntausend Drucke erzielen.

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 s

• 35 parts by weight of sodium metasilicate x 9 H ₂ 0,
• 140 parts by weight of glycerol,
• 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 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 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 none worse than this 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 on all supports, supports which had been prepared according to Examples 1 to 3 of Table 2, as described in Example D1, were coated with a positive-working photosensitive layer and printing forms were produced by exposure and development. With this, printing attempts were undertaken which delivered flawless prints up to a print run of 210,000. A printing form which was produced in an analogous manner with a carrier of Comparative Example A (Table 2) showed poorer freewheeling behavior. After 170,000 prints, fine halftone dots were no longer reproduced correctly.

Claims (19)

1. plate, film or tape-shaped carrier material for offset printing plates, consisting of mechanically, chemically or electrochemically roughened and optionally anodized aluminum or one of its alloys, which carries on at least one side a hydrophilic coating of a polymer containing acid side groups, characterized in that the hydrophilic polymer contains at least 2 mol% units with acidic side groups and, in addition to the acidic side groups, at least 2 mol% units with basic groups capable of protonation. 2. Support material according to claim 1, characterized in that the hydrophilic polymer is a copolymer of a monomer unit provided with basic groups and a monomer unit carrying acid groups. 3. Support material according to claim 2, characterized in that the basic group-bearing monomer contains an amino group. 4. Support material according to claim 3, characterized in that the amino group contains at least one alkyl or aryl group 5. Support material according to claim 2, characterized in that the acid-bearing monomer contains a carboxyl group. 6. A carrier material according to claim 2, characterized in that the monomer carrying acid groups contains a sulfonic acid group. 7. A carrier material according to claim 2, characterized in that the monomer carrying acid groups contains a phosphonic acid group. 8. A carrier material according to claim 1, characterized in that the copolymer contains, in addition to the acidic and basic side groups, additional units without an acid / base effect. 9. Carrier material according to claim 1, characterized in that the copolymer has an average molecular weight of at least 1,000. 10. A carrier material according to claim 9, characterized in that the copolymer has an average molecular weight of 5,000 to 50,000. 11. A carrier material according to claim 9, characterized in that the copolymer has a molecular weight of more than 50,000. 12. Support material according to claim 1, characterized in that the monomer ratio of the basic monomer units present in the copolymer to the acidic monomer units is in the range from 2:98 to 98: 2. 13. Support material according to claim 12, characterized in that the molar ratio of the basic to the acidic monomer units is equimolar. 14. Support material according to claim 13, characterized in that the molar ratio of the ionic to the non-ionic monomer units ranges from 4:96 to 100: 0. 15. Support material according to claim 1, characterized in that the acid side groups are present as metal salts with metal cations. 16. Support material according to one of claims 1 to 15, characterized in that the metal cation of the coating is a V ⁵⁺ - Bi ³⁺ -, Al ³⁺ -, Fe ³⁺ -, Zr ⁴⁺ -, Sn ⁴⁺ -, Ca ²⁺ -, Ba ²⁺ -, Sr ²⁺ -, Ti ³⁺ - Co ²⁺ - Fe ²⁺ -, Ce ⁴⁺ -, Mn ²⁺ - Ni ²⁺ -, Cu ^{2 + -,} Zn Is ^{2 + -} or Mg ²⁺ -lon. 17. A method for producing a support material for offset printing plates according to one of claims 1 to 16, characterized in that the aluminum or one of its alloys with the dissolved copolymers in a concentration of 0.02 to 5.0 wt .-% in aqueous, optionally acidic solution coated by dipping or electrochemical treatment and the layer is then dried. 18. A method for producing a carrier material according to one of claims 1 to 17, characterized in that the aluminum or one of its alloys first with a 0.01 to 10.0% solution of the polymers according to the invention and then with a 0.1% ige to saturated, preferably aqueous solution of a salt with the cations V ⁵⁺ , Bi3 +, Al ³⁺ , Fe ³⁺ , Zr ⁴⁺ , Sn ⁴⁺ , Ca ²⁺ , Ba ²⁺ , S _r ²⁺ , Ti ³⁺ , C _o ²⁺ , Fe ²⁺ , Mn ²⁺ , Ni ²⁺ , Cu ²⁺ , Ce ⁴⁺ , Zn ²⁺ or Mg ^{2+ are} treated and the layer produced from the reaction products is dried. 19. Use of a carrier material according to one of claims 1 to 16 for coating with light-sensitive substances.