EP0160920A2 - One-step electrochemical image-forming process for reproduction sheets - Google Patents

Abstract

In the method for image formation for reproduction layers which may be sensitive to radiation, the image on the multilayer material is produced with at least one electrically conductive layer and the reproduction layer by the action of electrical current via at least one needle-shaped electrode in the presence of an aqueous electrolyte solution, as a result of which the layer parts which result in the non-image areas can be removed by the electrochemical treatment. In particular, an electrolyte solution is used which has a pH in the range from 2.0 to 10.0 and contains at least one salt in a concentration of 0.1% by weight up to the saturation limit of the solution on the respective salt. In addition, the electrolyte solution can also contain a surfactant in a concentration of 0.1 to 5% by weight.

Description

The invention relates to a one-stage imaging and development or stripping process for reproduction layers in an aqueous electrolyte solution.

Reproduction layers sensitive to radiation (light) are used, for example, in the production of offset printing forms or photoresists (both hereinafter referred to as copying materials), ie they are generally applied to a layer support by the consumer or by the industrial manufacturer. Metals such as zinc, magnesium, chromium, copper, brass, steel, silicon, aluminum or combinations of these metals, plastic films, paper or similar materials are used as layer supports in these copying materials. These substrates can be coated with the radiation-sensitive reproduction layer without a modifying pretreatment, but preferably after carrying out a surface modification such as mechanical, chemical and / or electrochemical roughening, oxidation and / or treatment with hydrophilizing agents (e.g. in the case of substrates for offset printing plates) . In addition to at least one radiation-sensitive compound, the usual radiation-sensitive reproduction layers usually also contain an organic binder (resins or the like) and, if appropriate, also plasticizers, pigments, dyes, wetting agents, sensitizers, adhesive agents medium, indicators and other common tools. These reproduction layers are developed after their irradiation (exposure) in order to produce an image from them, for example a printing form or a photoresist is thus obtained; in the case of electrophotographic working layers, the development corresponds to the stripping. In the context of the present invention, however, the term “reproduction layers” is also to be understood as meaning those which do not contain a radiation-sensitive compound but contain the remaining components listed, ie in particular an organic binder.

EP-A 0 073 445 (= ZA-A 82/5879) describes a process for developing irradiated reproduction layers in which the non-image-forming parts of the layer are removed with an aqueous electrolyte solution by electrochemical treatment. In particular, a solution is used which has a pH of 2.0 to 10.0 and contains at least one salt in a concentration of 0.1% up to the saturation limit of the solution on the respective salt. In addition, the electrolyte can also contain a surfactant in a concentration of 0.1 to 5%. At. However, this process requires separate irradiation before the development stage.

• - aus der DE-C 24 33 448 (= US-A 4 086 853) der Einsatz eines elektrisch-empfindlichen Aufzeichnungsblattes mit a) einer hydrophoben Unterschicht (z. B. aus Polyester), b) einer darauf angeordneten elektrisch-leitenden, durch Stromeinwirkung mittels eines Stifts örtlich entfernbaren, hydrophilen Schicht (z. B. aus Aluminium) und c) einer Schicht, die nach der Stromeinwirkung von der Schicht gemäß b) ablösbar ist (z. B. aus einem Cellulosederivat, einem Weichmacher und einem Pigment),
• - aus der DE-A 25 14 682 (= GB-A 1 490 732) der Einsatz eines elektrisch-empfindlichen Aufzeichnungsmaterials mit a) einer elektrisch-leitenden, durch Stromeinwirkung nicht entfernbaren, oleophilen Schicht (z. B. aus Aluminium) und b) einer darauf angeordneten, durch Stromeinwirkung mittels eines Stifts örtlich entfernbaren, oleophoben Schicht aus Silikonkautschuk und
• - aus der EP-A 0 030 642 ein Verfahren zur Herstellung : einer Druckform aus einem flächigen Material mit a) einer hydrophoben Trägerschicht (z. B. aus Polyester), b) einer hydrophilen, elektrisch-leitenden Zwischenschicht (z. B. aus Aluminium) und c) einer abschließenden, dielektrischen Schutzschicht (z. B. aus AI₂0₃) durch Elektroerosion, wobei durch Einwirkung von Elektroden sowohl die Schicht c) als auch b) entfernt werden.

Methods are also known from the prior art, in which a printing form is also used without an irradiation and / or development step and thus also without the use of the otherwise usual reproduction layers containing a radiation-sensitive compound, for example

• - From DE-C 24 33 448 (= US-A 4 086 853) the use of an electrically sensitive recording sheet with a) a hydrophobic underlayer (for example made of polyester), b) an electrically conductive layer arranged thereon Impact of electricity by means of a stick of a locally removable, hydrophilic layer (e.g. made of aluminum) and c) a layer which can be removed from the layer according to b) after exposure to electricity (e.g. of a cellulose derivative, a plasticizer and a pigment) ,
• - from DE-A 25 14 682 (= GB-A 1 490 732) the use of an electrically sensitive recording material with a) an electrically conductive, oleophilic layer which cannot be removed by the action of current (for example made of aluminum) and b ) an oleophobic layer of silicone rubber which is arranged thereon and can be removed locally by the action of a pin and
• - From EP-A 0 030 642 a process for the production: a printing form made of a flat material with a) a hydrophobic carrier layer (e.g. made of polyester), b) a hydrophilic, electrically conductive intermediate layer (e.g. made of Aluminum) and c) a final, dielectric protective layer (z. B. from Al ₂ 0 ₃ ) by electroerosion, wherein both the layer c) and b) are removed by the action of electrodes.

Although these processes already lead to printing forms, they cannot be used to achieve long print runs; in addition, the materials effective as hydrophilic or hydrophobic or oleophobic or oleophilic points on the printing form result in severe practical restrictions, for example with regard to the printing press, the chemicals and printing inks to be used and / or the paper.

It is therefore an object of the present invention to develop a method for electrochemical image formation on a flat support which can be carried out in one stage using commercially available reproduction layers on customary support materials. In addition, the method should make it possible for digitally available information to be applied directly to a material to be used later as printing form without a detour via irradiation (imaging), so that the otherwise customary imaging and development stages coincide.

The invention is based on a method for electrochemical imaging on a multilayer sheet material with at least one electrically conductive layer by the action of electric current via at least one needle-shaped electrode. The process according to the invention is then characterized in that a) the multilayered sheet material has a reproduction layer which may contain at least one radiation-sensitive compound, b) at least one needle-shaped electrode from acts on the side of the multilayer sheet material that carries the reproduction layer, and c) both the electrode (s) and the multilayer sheet material are arranged in interaction with an aqueous electrolyte solution.

In this method, the layer parts resulting from the non-image areas are removed by the electrochemical treatment. The aqueous electrolyte solution generally has a pH in the range from 1 to 14, in particular from 2.0 to 10.0, and in addition to the main constituent contains water as a dissociated compound, in particular at least one salt of an organic or inorganic acid in a concentration from 0.1% by weight to the saturation limit of the solution on the respective salt. These salt solutions can also be in the form of a buffer system and then, in addition to the salt content, also contain weak acids (such as acetic acid) or weak bases (such as ammonia); it can also be expedient to shift the pH of the salt solutions by adding acids or bases, but the pH values stated above should not be exceeded or undershot. As the dissociated compound, the aqueous electrolyte can also contain acids (such as acetic acid or boric acid) in the specified pH range instead of the salts preferably used.

The salts which can be used in the aqueous electrolyte in the process according to the invention include, in particular, those which as cations Li ⁺ , Na ⁺ , K ⁺ , NH ₄ ⁺ , A1 ³⁺ , Fe ²⁺ , Fe ³⁺ , V ⁵⁺ , Ca ²⁺ , Mg ²⁺ , Sr ²⁺ or Ba ²⁺ and as anions SO ₄ ^2- , S ₂ O ₃ SCN ^- , CO ₃ ^2- , CH ₃ COO ^- , NO ₃ ^‾ , NO ₂ ^‾ , PO ₄ ^3- , BO ₂ ^-, polyphosphates, polyborates, F ^- , C1 ^- , Br ^- , BF ₄ ^- , N ₃ ^-, VO ₃ ^-, anions of alkyl sulfates (sulfuric acid monoalkyl ester anions) from C ₇ to C ₁₆ or their contain corresponding hydrogen salts.

To make the process according to the invention more uniform and faster, the aqueous electrolyte solution can also contain a surfactant which is different from the dissociated compounds listed above and is preferably added in a concentration of 0.1 to 5% by weight. Both nonionic and anionogenic or cationogenic surfactants can be used; however, they should be of a slightly lubricating type, especially when the process according to the invention is carried out in processing machines. Suitable surfactants have for example found: alkali metal or ammonium salts of the monoalkyl sulfate having alkyl groups of C7 is C _16, ethoxylated alcohols and phenols, ethoxylated fatty amines, or block polymers based on alkylene oxides (especially based on ethylene oxide and propylene oxide).

According to the method according to the invention, it is possible to differentiate image-wise different types of non-irradiated reproduction layers in moderate solutions which do not contain any organic solvent or other large amounts of environmentally harmful auxiliaries. The resolution that can be achieved corresponds to that of conventional radiation and developments that are not to be used electrochemically.

Since the pH of an unbuffered aqueous Elektrol ^y tlö- chemical changes due to solution (electro) at its components during the execution of the method according to the invention change, is recommended for multiple use of the aqueous electrolyte solution, the use of an additional buffer system.

The concentration of the dissociated compound in the aqueous electrolyte solution can be between 0.1% by weight, in particular 1% by weight, and the respective saturation concentration of the dissociated compound; in general, concentrations of up to 5% by weight are sufficient. If the concentration of the aqueous electrolyte is less than 0.1% by weight, the conductivity of the solution is usually too low, so that the resulting current density becomes too low to achieve rapid development. The temperature of the aqueous electrolyte can range from room temperature to the boiling point of the electrolyte system, but a temperature of 20 ° to 70 is preferred _. C complied with. It is generally not necessary to mix the aqueous electrolyte while the process according to the invention is being carried out.

The method according to the invention is carried out with direct current or alternating current of different frequency and modulation, and pulsed direct current can also be used will. The current density can in principle also be outside a range from 1 to 100 A / dm ² , but this range is preferred, since otherwise the heating of the aqueous electrolyte solution becomes too strong and / or the duration or quality of the image formation can be adversely affected . The current density increases at the beginning of the electrochemical imaging, remains at a level for a certain time and increases again slightly towards the end of the treatment.

During electrochemical imaging, hydrogen is generally released at the cathode by discharging H ⁺ (H ₃ O ⁺ ) ions. It is assumed that this causes the pH to increase locally and causes the image-differentiating detachment. Due to the occasionally high pH value, the support of the reproduction layer can be attacked in places in some aqueous electrolyte solutions; however, the actual image formation is not affected by this, and this attack can - if necessary at all - be reduced by adding corrosion inhibitors. Inadequate wetting of the reproduction layer by the aqueous electrolyte solution can occasionally lead to the appearance of layer residues in the areas which are actually free of layers (non-image areas), but this can be achieved by using a surfactant suitable for the reproduction layer in question or briefly "soaking" the plate with the aqueous electrolyte solution the actual electrochemical imaging are avoided.

The term "needle-shaped electrode" is to be understood as an elongated body made of a material which is as inert as possible (ie which does not degrade during the process according to the invention), such as graphite, gold or platinum, and which has the smallest possible tip in order to achieve the best possible resolution and To achieve the finest image or non-image points. This electrode or these electrodes are guided as close as possible over the flat material to be imaged.

A plurality of needle-shaped electrodes can also be used to image larger areas; this can also be possible to accelerate the method. Like just one electrode, these electrodes are controlled by a device which contains the image information in digitized form (for example a "computer-to-plate" system). The counter electrode is the electrically conductive layer of the multilayer sheet material. The aqueous electrolyte solution must be arranged in relation to the multilayer sheet material and the needle-shaped electrode (s) in such a way that, in interaction with the two bodies acting as electrodes, it can bring about an imagewise differentiation in the reproduction layer, for example by immersing the body in the solution. In the process according to the invention, the reproduction layers include not only the usual (see below) known radiation-sensitive layers, but also those of comparable composition, but none contain radiation sensitive compound; that is to say, reproduction layers are to be understood as layers which enable an imagewise differentiation in the method according to the invention.

In a preferred embodiment of the method according to the invention, the reproduction layer to be treated, which is part of the multilayer sheet material with at least one electrically conductive layer, is contacted by immersion with the aqueous electrolyte solution. An edge of the flat material should protrude from the surface of the electrolyte bath, a power connection can then be attached to this part. Another way of supplying power is to make contact via the material back, which has no reproduction layer. The needle-shaped electrode should, in particular, be arranged at a uniform distance from the flat material, so that a uniform current density can be set at any point on the flat material to be imaged. The advantage of the method is that the size of the non-image points can be controlled by varying the current density and time. The control pulses can, for. B. come directly from a computer-to-plate system. The uncoated back of the flat material to be treated should preferably be in contact with a non-conductive material in order to avoid unnecessary consumption of electrical energy. Another possibility is in the insulation of the back of the material, whereby the plate is guided in tight grooves in the electrolyte bath container. Likewise, the needle-shaped electrode (s) should suitably be largely insulated.

The reproduction layer to be treated is present, in particular, as part (radiation-sensitive layer) of an offset printing plate or as a resist (photoresist layer) applied to a carrier material; it generally contains a polymeric binder which dissolves under the action of the electrical current from the needle-shaped electrode and releases the underlying part of the flat material. However, coatings based on a polymeric binder which do not contain any radiation-sensitive compound are also understood to be covered by the invention, but are preferably used as radiation-sensitive layers. Electrically conductive carrier materials are suitable as carrier materials, which include, for example, those based on zinc, chromium, magnesium, copper, brass, steel, silicon, aluminum or combinations of these metals. These can be provided with a suitable reproduction layer without a special modifying pretreatment, but this coating is preferably carried out only after a surface modification such as mechanical, chemical or electrochemical roughening, oxidation and / or treatment with hydrophilizing agents (in particular in the case of supports for offset printing plates).

The particularly suitable substrates for the production of offset printing plates include those made of aluminum or one of its alloys, which for example have a content of more than 98.0% by weight, in particular more than 98.5% by weight, of Al and proportions of Si , Fe, Ti, Cu, Zn, Mn and / or Mg.

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. roughened by AC treatment in aqueous HCl or HN0 ₃ solutions). 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 1.5 to 10 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 aluminum strip can be pre-cleaned before roughening; it includes, for example, treatment with aqueous NaOH solution with or without degreasing agent and / or complexing agents, trichlorethylene, acetone, methanol or other commercially available aluminum stains. The roughening or, in the case of several roughening stages, also between the individual stages, a removal treatment can additionally be carried out, in particular a maximum of 2 g / m ² be removed (up to 5 g / m ² between the stages); In general, aqueous solutions of alkali metal hydroxide or aqueous solutions of alkaline salts or aqueous acid solutions based on HN0 ₃ , H ₂ SO ₄ or H ₃ PO ₄ are used as abrasive solutions. In addition to an abrasive treatment stage between the roughening stage and a subsequent anodizing stage, non-electrochemical treatments are also known which essentially have only a rinsing and / or cleaning effect and, for example, for removing deposits formed during roughening ("Schmant") or simply for removal serve from leftovers; For example, dilute aqueous alkali hydroxide solutions or water are used for these purposes.

After the roughening process or processes, an anodic oxidation of the aluminum can then optionally follow in a further process step to be used, for example in order to improve 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; in particular, H ₂ S0 ₄ and H ₃ P0 _{4 are used} alone, in a mixture and / or in a multi-stage anodizing process. 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.

The stage of anodic oxidation of the aluminum support material can also be followed by one or more post-treatment stages. Aftertreatment is understood to mean in particular a hydrophilizing chemical or electrochemical treatment of the aluminum oxide layer, for example immersion treatment of the material in an aqueous polyvinylphosphonic acid solution according to DE-C 16 21 478 (= GB-A 1 230 447), an immersion treatment in an aqueous alkali silicate Solution according to DE-B 14 71 707 (= US-A 3 181 461) or an electrochemical treatment (anodization) in an aqueous alkali silicate solution according to DE-A 25 32 769 (= US-A 3 902 976). These post-treatment stages serve in particular to additionally increase the hydrophilicity of the aluminum oxide layer, which is often sufficient, while at least the other known properties of this layer are retained.

Reproduction layers sensitive to radiation (light) are to be understood in principle as those which - in the otherwise customary methods which, however, are not required according to the invention - provide an image-like area after irradiation (exposure), optionally with subsequent development and / or fixation that can be printed.

• positiv-arbeitende, o-Chinondiazide, insbesondere o-Naphthochinondiazide wie Naphthochinon-(1,2)-diazid-(2)-sulfonsäureester oder -amide, die nieder- oder höhermolekular sein können, als lichtempfindliche Verbindung enthaltende Reproduktionsschichten, 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, 1 124 817 und 2 331 377 und den EP-A 0 021 428 und 0 055 814 beschrieben werden;
• negativ-arbeitende Reproduktionsschichten mit Kondensationsprodukten 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 enthaltende Reproduktionsschichten, beispielsweise nach der DE-C 20 65 732, die Produkte mit mindestens je einer Einheit aus a) einer kondensationsfähigen aromatischen Diazoniumsalzverbindung und b) einer kondensationsfähigen Verbindung wie einem Phenolether oder einem aromatischen Thioether, verbunden durch ein zweibindiges, von einer kondensationsfähigen Carbonylverbindung abgeleitetes Zwischenglied wie einer Methylengruppe aufweisen;
• positiv-arbeitende Schichten nach der DE-A 26 10 842, der DE-C 27 18 254 oder der DE-A 29 28 636, die eine bei Bestrahlung Säure abspaltende Verbindung, eine monomere oder polymere Verbindung, die mindestens eine durch Säure abspaltbare C-0-C-Gruppe aufweist (z. B. eine Orthocarbonsäureestergruppe oder eine Carbonsäureamidacetalgruppe) und gegebenenfalls ein Bindemittel enthalten;
• negativ-arbeitende Schichten aus photopolymerisierbaren

In addition to the layers containing silver halides used in many fields, various others are also known, such as e.g. B. in "Light-Sensitive Systems" by Jaromir Kosar, John Wiley & Sons Verlag, New York 1965 are described: 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-diazo-quinones such as naphthoquinonediazides, p-diazo-quinones or diazonium salt condensates (Kosar, Chapter 7). The suitable layers also include the electrophotographic layers, ie those which contain an inorganic or organic photoconductor. In addition to the radiation-sensitive substances, these layers can of course also other components such. B. contain resins, dyes or plasticizers. In particular, the following radiation-sensitive masses or compounds can be used in the reproduction layers:

• positive-working, o-quinonediazides, in particular o-naphthoquinonediazides such as naphthoquinone- (1,2) -diazid- (2) -sulfonic acid esters or amides, which can be of low or higher molecular weight, as a photosensitive compound-containing reproduction layers, for example in the DE-C 854 890, 865 109, 879 203, 894 959, 938 233, 1 109 521, 1 144 705, 1 118 606, 1 120 273, 1 124 817 and 2 331 377 and EP-A 0 021 428 and 0 055 814;
• negative working reproduction layers with 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;
• Reproductive layers containing negative-working, mixed condensation products of aromatic diazonium compounds, for example according to DE-C 20 65 732, the products with at least one unit each of a) a condensable aromatic diazonium salt compound and b) a condensable compound such as a phenol ether or an aromatic thioether, connected by have a double bonded intermediate derived from a condensable carbonyl compound such as a methylene group;
• positive-working layers according to DE-A 26 10 842, DE-C 27 18 254 or DE-A 29 28 636, which contain a compound which cleaves off under irradiation, a monomeric or polymeric compound which has at least one C-cleavable by acid -0-C group (z. B. an orthocarboxylic acid ester group or a carboxylic acid amide acetal group) and optionally contain a binder;
• negative working layers made of photopolymerizable

• 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.

Monomers, photoinitiators, binders and optionally other additives; the monomers used are, for example, acrylic and methacrylic acid esters or reaction products of diisocyanates with partial esters of polyhydric alcohols, as described, for example, in US Pat. Nos. 2,760,863 and 3,060,023 and DE-A 20 64 079 and 23 61 041;

• Negative-working layers according to DE-A 30 36 077, which contain a diazonium salt polycondensation product or an organic azido compound as a photosensitive compound and a high molecular weight polymer with pendant alkenylsulfonyl or cycloalkenylsulfonylurethane groups as a binder.

It can also be photoconductive layers such as z. B. in DE-C 11 17 391, 15 22 497, 15 72 312, 23 22 046 and 23 22 047 can be used.

The layers described above and containing at least one radiation-sensitive compound can also be used in the process according to the invention, provided that they contain at least one binder, without the presence of the radiation-sensitive compound. The following organic polymers which are soluble in the aqueous electrolyte solution are particularly suitable: polyamides, polyesters, alkyd resins, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide, polyacetals, gelatin and / or cellulose ethers.

The thickness of the reproduction layer can range from approximately 0.1 μm to approximately 1 mm or more.

In the cases in which the reproduction layers contain radiation-sensitive compounds which result in a negative working system, it is advisable to reexpose or reheat the flat material from the side of the reproduction layer; in the case of a positive working system, no special post-exposure is carried out. Of the radiation-sensitive reproduction layers, the positive working ones are preferred in the method according to the invention. In order to achieve an even longer print run, after carrying out the image generation according to the invention, increasing the mechanical and / or chemical stability of the image areas, it is possible to "burn in", i. H. a thermal or comparable post-treatment of the flat material.

With the method according to the invention, it is thus possible to combine the imaging and development method for reproduction layers, which is otherwise carried out in two stages, in one stage.

In the following examples and the description above, the percentages are by weight, unless otherwise stated. Parts by weight relate to parts by volume like g to cm ³ . The reproductive layers to be treated are on conductive supports and are - unless otherwise stated wrote - connected as a cathode in a DC circuit, the needle-shaped electrode (s) then as an anode (s). Unless otherwise stated, the electrolyte temperature is 25 to 30 ° C., the distance of the material to be treated from the counterelectrode is kept as short as possible without causing a short circuit. The course of the current density can generally be represented as follows: the current density initially rises to a certain value during a few msec, remains at this level for a few msec and can increase slightly again towards the end of the electrolytic development. If no special comments are given, the treated materials are practical.

example 1

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

The following positive-working photosensitive solution is applied to an electrochemically roughened and anodized aluminum foil by flow coating with a slot die:

• 6.6 parts by weight of cresol-formaldehyde novolak (with a softening range of 105 - 120 ° C according to DIN 53 181)
• 1.1 parts by weight of the 4- (2-phenyl-prop-2-yl) phenyl ester of naphthoquinone- (1,2) -diazide- (2) -sulfonic acid- (4)
• 0.6 parts 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 a 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

After drying, this plate is imaged in an aqueous solution containing 3% lithium sulfate and 1% sodium octyl sulfate (sodium salt of sulfuric acid monooctyl ester) at pH 3.5 with a needle electrode with a voltage which changes depending on the non-image point size .

Example 2

• 1,15 Gew.-Teile des Veresterungsproduktes aus 1 Mol 2,3,4-Trihydroxybenzophenon und 2 Mol Naphthochinon-(1,2)-diazid-(2)-5-sulfonsäurechlorid
• 7,15 Gew.-Teile eines Phenol-Formaldehyd-Novolaks (mit 14 % phenolischen OH-Gruppen und einem Erweichungspunkt von 110 - 120 °C nach DIN 53 181)
• 0,64 Gew.-Teile 2,2'-Bis-fnaphthochinon-(1,2)-diazid-(2)-sulfonyloxy-(5)1-dinaphthyl-(1,1')-methan
• 0,15 Gew.-Teile Kristallviolett
• 0,08 Gew.-Teile Sudangelb GGN (C. I. 11021)
• 92,25 Gew.-Teile Gemisch aus 40 Vol.-Teilen Ethylenglykolmonomethylether und 50 Vol.-Teilen Tetrahydrofuran

An aluminum foil mechanically roughened with steel brushes is coated with the following solution and then in the drying tunnel at temperatures up to 100 _. C dried:

• 1.15 parts by weight of the esterification product from 1 mol of 2,3,4-trihydroxybenzophenone and 2 mol of naphthoquinone- (1,2) -diazid- (2) -5-sulfonic acid chloride
• 7.15 parts by weight of a phenol-formaldehyde novolak (with 14% phenolic OH groups and a softening point of 110-120 ° C according to DIN 53 181)
• 0.64 parts by weight of 2,2'-bis-naphthoquinone- (1,2) -diazide- (2) -sulfonyloxy- (5) 1-dinaphthyl- (1,1 ') - methane
• 0.15 part by weight of crystal violet
• 0.08 part by weight Sudangelb GGN (CI 11021)
• 92.25 parts by weight of a mixture of 40 parts by volume of ethylene glycol monomethyl ether and 50 parts by volume of tetrahydrofuran

This plate is electrochemically imaged with a needle electrode in an aqueous solution containing 3% lithium sulfate and 1% sodium octyl sulfate at a pH of 7.5 at about 60 V depending on the spot size.

Example 3

• 14,00 Gew.-Teilen eines Mischpolymerisats aus Methylmethacrylat und Methacrylsäure mit einem mittleren Molekulargewicht von 40000 und einer Säurezahl von 90 bis 115
• 14,00 Gew.-Teilen 1,1,1-Trimethylol-ethan-triacrylat
• 2,00 Gew.-Teilen 1,6-Dihydroxy-ethoxy-hexan
• 0,50 Gew.-Teilen 9-p-Hydroxyphenylacridin
• 130,00 Gew.-Teilen Ethylenglykolmonoethylether

wird auf eine elektrochemisch aufgerauhte, anodisch oxidierte und mit einer wäßrigen Polyvinylphosphonsäure-Lösung hydrophilierte Aluminiumfolie aufgetragen, getrocknet und in einer wäßrigen Lösung mit einem Gehalt an 3 % Lithiumsulfat und 1 % Natrium-octylsulfat bei einem pH-Wert von 3,5 bei ca. 10 V abhängig von der Punktgröße elektrochemisch mit einer Nadelelektrode bebildert und dann bei 220 °C während 5 min getrocknet.A negative working photosensitive solution consisting of

• 14.00 parts by weight of a copolymer of methyl methacrylate and methacrylic acid with an average molecular weight of 40,000 and an acid number of 90 to 115
• 14.00 parts by weight of 1,1,1-trimethylol ethane triacrylate
• 2.00 parts by weight of 1,6-dihydroxy-ethoxy-hexane
• 0.50 part by weight of 9-p-hydroxyphenylacridine
• 130.00 parts by weight of ethylene glycol monoethyl ether

is applied to an electrochemically roughened, anodic oxi dated and coated with an aqueous polyvinyl phosphonic acid solution aluminum foil, dried and electrochemically in an aqueous solution containing 3% lithium sulfate and 1% sodium octyl sulfate at a pH of 3.5 at about 10 V depending on the point size Imaged with a needle electrode and then dried at 220 ° C for 5 minutes.

Example 4

• 26,75 Gew.-Teile einer 8 %igen Lösung des Umsetzungsproduktes eines Polyvinylbutyrals (mit einem Molekulargewicht von 70000 bis 80000, bestehend aus 71 % Vinylbutyral-, 2 % Vinylacetat- und 27 % Vinylalkohol-Einheiten) mit Propenylsulfonylisocyanat
• 2,14 Gew.-Teile 2,6-Bis-(4-azido-benzol)-4-methylcyclohexanon
• 0,23 Gew.-Teile Rhodamin 6 GDN extra
• 0,21 Gew.-Teile 2-Benzoylmethylen-1-methyl-B-naphtho- thiazolin
• 100 Vol.-Teile Ethylenglykolmonomethylether
• 50 Vol.-Teile Tetrahydrofuran.

The following negative-working light-sensitive layer is applied to an electrochemically roughened, anodically oxidized and foil-hydrophilized with an aqueous polyvinylphosphonic acid solution:

• 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% vinyl butyral, 2% vinyl acetate and 27% vinyl alcohol units) with propenylsulfonyl isocyanate
• 2.14 parts by weight of 2,6-bis (4-azido-benzene) -4-methylcyclohexanone
• 0.23 parts by weight of Rhodamine 6 GDN extra
• 0.21 part by weight of 2-benzoylmethylene-1-methyl-B-naphthothiazoline
• 100 parts by volume of ethylene glycol monomethyl ether
• 50 parts by volume of tetrahydrofuran.

The electrochemical point-like imaging takes place in an aqueous solution containing 1.5% lithium carbonate and 1% sodium octyl sulfate at a pH of 8 with about 60 V. After rubbing out and drying at 220 ° C., a printing form which is sufficient for practical use is obtained.

Example 5

• 10,00 Gew.-Teilen 2-Vinyl-5-(4'-diethylaminophenyl)-4-(2'-chlorphenyl)-oxazol
• 10,00 Gew.-Teilen eines Mischpolymerisats aus Styrol und Maleinsäureanhydrid (mit einem Erweichungspunkt von 210°C)
• 0,02 Gew.-Teilen Rhodamin FB (C. I. 45 170)
• 300,00 Gew.-Teilen Ethylenglykolmonomethylether

wird auf eine elektrochemisch aufgerauhte, anodisch oxidierte und mit einer wäßrigen Polyvinylphosphonsäure-Lösung hydrophilierte Aluminiumfolie aufgetragen. Die getrocknete Platte kann dann in einer 1,5 %igen wäßrigen Lithiumcarbonat-Lösung mit einem Gehalt an 1 % Natriumoytylsulfat mit 60 V während 8 bis 12 sec bei einem pH-Wert von 8 und einer Temperatur von 50°C nach einer vorhergehenden nichtelektrolytischen Standzeit in der Lösung von 30 sec bildmäßig, rasterförmig mit der Nadelelektrode elektrochemisch entschichtet werden.An electrophotographic working layer consisting of:

• 10.00 parts by weight of 2-vinyl-5- (4'-diethylaminophenyl) -4- (2'-chlorophenyl) oxazole
• 10.00 parts by weight of a copolymer of styrene and maleic anhydride (with a softening point of 210 ° C.)
• 0.02 part by weight of Rhodamine FB (CI 45 170)
• 300.00 parts by weight of ethylene glycol monomethyl ether

is applied to an electrochemically roughened, anodically oxidized aluminum foil and hydrophilized with an aqueous polyvinylphosphonic acid solution. The dried plate can then in a 1.5% aqueous lithium carbonate solution containing 1% sodiumoytyl sulfate at 60 V for 8 to 12 seconds at a pH of 8 and a temperature of 50 ° C after a previous non-electrolytic service life in the solution of 30 sec, electrochemically decoated in a grid pattern with the needle electrode.

Example 6

The electrophotographically working layer from Example 5 is applied to an aluminum support which has been mechanically roughened by dry brushing and processed further according to the instructions in Example 5. The imagewise stripping takes place in the same electrolyte under the same conditions, but without a previous non-electrochemical exposure phase.

Example 7

• 1,0 Gew.-Teile Polykondensationsprodukt aus 1 Mol 3-Methoxy-diphenylamin-4-diazoniumsulfat und 1 Mol 4,4'-Bis-methoxymethyl-diphenylether, ausgefällt als Salz der Mesitylensulfonsäure,
• 1,8 Gew.-Teile nichtplastifiziertes Harnstoffharz (mit einer Viskosität in 65 %iger Lösung in Butanol/Xylol bei 20^*C von ca. 6000 mPa.s und einer Säurezahl unterhalb 3)
• 0,4 Gew.-Teile Kristallviolett
• 98,0 Gew.-Teile Ethylenglykolmonomethylether

An electrochemically roughened, anodically oxidized aluminum support which has been hydrophilized with an aqueous solution of polyvinylphosphonic acid is coated with the following negative-working light-sensitive solution:

• 1.0 part by weight of polycondensation product of 1 mol of 3-methoxy-diphenylamine-4-diazonium sulfate and 1 mol of 4,4'-bis-methoxymethyl-diphenyl ether, precipitated as the salt of mesitylenesulfonic acid,
• 1.8 parts by weight of non-plasticized urea resin (with a viscosity in 65% solution in butanol / xylene at 20 ^* C of approx. 6000 mPa.s and an acid number below 3)
• 0.4 part by weight of crystal violet
• 98.0 parts by weight of ethylene glycol monomethyl ether

The electrochemical image treatment is carried out in an aqueous solution containing 3% sodium phosphate and 3% of an ethoxylated isotridecyl alcohol with 8 ethylene oxide units at a pH of 7 by applying about 20 V depending on the point size (the pH is adjusted with H ₃ P0 ₄ ). The plate is imaged and then dried at 220 ° C or hardened by post-exposure. The print run of a plate treated in this way is 80,000 prints.

Example 8

• 25,0 Gew.-Teilen Bis-(5-ethyl-5-butyl-1,3-dioxan-2-yl)-ether des 2-Ethyl-2-butyl-1,3-propan- diols
• 71,0 Gew.-Teilen eines Kresol-Formaldehyd-Novolaks
• 0,7 Gew.-Teilen Kristallviolett-Base
• 3,0 Gew.-Teilen 2-(Acenaphth-5-yl)-4,6-bis-trichlormethyl-s-triazin
• 900,0 Gew.-Teilen Ethylenglykolmonomethylether

wird auf eine elektrochemisch aufgerauhte und anodisch oxidierte Aluminiumfolie aufgetragen. Nach dem Trocknen kann die Folie in einer wäßrigen Lösung mit einem Gehalt an 3 % Lithiumsulfat mit 1 % Natrium-octylsulfat mit etwa 15 bis 20 V Spannung bei einem pH-Wert von 3,5 elektrochemisch bebildert werden.A positive working light sensitive solution consisting of:

• 25.0 parts by weight of bis (5-ethyl-5-butyl-1,3-dioxan-2-yl) ether of 2-ethyl-2-butyl-1,3-propanediol
• 71.0 parts by weight of a cresol-formaldehyde novolak
• 0.7 parts by weight of crystal violet base
• 3.0 parts by weight of 2- (acenaphth-5-yl) -4,6-bis-trichloromethyl-s-triazine
• 900.0 parts by weight of ethylene glycol monomethyl ether

is applied to an electrochemically roughened and anodized aluminum foil. After drying, the film can be electrochemically imaged in an aqueous solution containing 3% lithium sulfate with 1% sodium octyl sulfate with a voltage of about 15 to 20 V at a pH of 3.5.

Example 9

The plate from Example 3 is electrochemically treated in 6% aqueous sodium lauryl sulfate solution at a pH of 4.

Example 10

• 1,6 Gew.-Teile des Veresterungsproduktes aus 1 Mol 2,3,4-Trihydroxy-benzophenon und 2 Mol Naphthochinon-(1,2)-diazid-(2)-5-sulfonsäurechlorid
• 0,9 Gew.-Teile 2,2'-Bis-[naphthochinon-(1,2)-diazid-(2)-sulfonyloxy-(5) ]-dinaphthyl- (1,1 )-methan
• 6,4 Gew.-Teile Kresol-Formaldehyd-Novolak (mit dem Erweichungspunkt von 105° - 120°C nach DIN 53 181)
• 90,1 Gew.-Teile Gemisch aus 4 Vol.-Teilen Ethylenglykolmonomethylether, 5 Vol.-Teilen Tetrahydrofuran und 1 Vol.-Teil Essigsäurebutylester

An aluminum foil mechanically roughened and anodically oxidized by dry brushing is coated with a positive-working light-sensitive solution consisting of the following components:

• 1.6 parts by weight of the esterification product from 1 mol of 2,3,4-trihydroxy-benzophenone and 2 mol of naphthoquinone- (1,2) -diazid- (2) -5-sulfonic acid chloride
• 0.9 part by weight of 2,2'-bis- [naphthoquinone- (1,2) -diazide- (2) -sulfonyloxy- (5)] -dinaphthyl- (1,1) -methane
• 6.4 parts by weight cresol-formaldehyde novolak (with a softening point of 105 ° - 120 ° C according to DIN 53 181)
• 90.1 parts by weight of a 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

This coated film is octyl sulfate sodium in an aqueous solution containing 3% ammonium phosphate and 1% at a pH value of 7.5 (with H ₃ PO _4, a ^g e-asserted) electrochemically treated.

Example ¹ 1

• 6,6 Gew.-Teile Kresol-Formaldehyd-Novolak (mit dem Erweichungsbereich von 105° - 120°C nach DIN 53 181)
• 0,08 Gew.-Teile Kristallviolett
• 91,36 Gew.-Teile Gemisch aus 4 Vol.-Teilen Ethylenglykolmonomethylether, 5 Vol.-Teilen Tetrahydrofuran und 1 Vol.-Teil Essigsäurebutylester

The following solution, which contains no radiation-sensitive compound, is applied to an electrochemically roughened and anodized aluminum foil by flow coating with a slot die:

• 6.6 parts by weight of cresol-formaldehyde novolak (with a softening range of 105 ° - 120 ° C according to DIN 53 181)
• 0.08 part by weight of crystal violet
• 91.36 parts by weight of a 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

After drying, this plate is imaged in an aqueous solution containing 3% lithium sulfate and 1% sodium octyl sulfate (sodium salt of monoocyte sulfuric acid) at pH 3.5 with a needle electrode with a voltage which changes depending on the point size.

Example 12

• 7,15 Gew.-Teile eines Phenol-Formaldehyd-Novolaks (mit 14 % phenolischen OH-Gruppen und einem Erweichungspunkt von 110' - 120°C nach DIN 53 181)
• 0,15 Gew.-Teile Kristallviolett
• 0,08 Gew.-Teile Sudangelb GGN (C. I. 11021)
• 92,25 Gew.-Teile Gemisch aus 40 Vol.-Teilen Ethylenglykolmonomethylether und 50 Vol.-Teilen Tetrahydrofuran

An aluminum foil mechanically roughened with steel brushes is coated with the following solution containing no radiation-sensitive compound and then dried in the drying tunnel at temperatures up to 100 ° C:

• 7.15 parts by weight of a phenol-formaldehyde novolak (with 14% phenolic OH groups and a softening point of 110 '- 120 ° C according to DIN 53 181)
• 0.15 part by weight of crystal violet
• 0.08 part by weight Sudangelb GGN (CI 11021)
• 92.25 parts by weight mixture of 40 parts by volume ethylene glycol colmonomethyl ether and 50 parts by volume of tetrahydrofuran

This plate is electrochemically imaged with a needle electrode in an aqueous solution containing 3% lithium sulfate and 1% sodium octyl sulfate at a pH of 7.5 at about 60 V depending on the spot size.

Example 13

• 10,00 Gew.-Teilen eines Mischpolymerisats aus Styrol und Maleinsäureanhydrid (mit einem Erweichungspunkt von 210°C)
• 300,00 Gew.-Teilen Ethylenglykolmonomethylether

wird auf eine elektrochemisch aufgerauhte, anodisch oxidierte und mit einer wäßrigen Polyvinylphosphonsäure-Lösung hydrophilierte Aluminiumfolie aufgetragen. Die getrocknete Platte kann dann in einer 1,5 %igen wäßrigen Lithiumcarbonat-Lösung mit einem Gehalt an 1 % Natriumoytylsulfat mit 60 V während 8 bis 12 sec bei einem pH-Wert von 8 und einer Temperatur von 50°C nach einer vorhergehenden nichtelektrolytischen Standzeit in der Lösung von 30 sec bildmäßig, rasterförmig mit der Nadelelektrode elektrochemisch entschichtet werden.A non-electrophotographic working layer consisting of:

• 10.00 parts by weight of a copolymer of styrene and maleic anhydride (with a softening point of 210 ° C.)
• 300.00 parts by weight of ethylene glycol monomethyl ether

is applied to an electrochemically roughened, anodically oxidized aluminum foil and hydrophilized with an aqueous polyvinylphosphonic acid solution. The dried plate can then in a 1.5% aqueous lithium carbonate solution containing 1% sodiumoytyl sulfate at 60 V for 8 to 12 seconds at a pH of 8 and a temperature of 50 ° C after a previous non-electrolytic service life in the solution of 30 sec, electrochemically decoated in a grid pattern with the needle electrode.

Example 14

The layer from example 13 is applied to an aluminum support which has been mechanically roughened by dry brushing and processed further as described in example 13. The imagewise stripping takes place in the same electrolyte under the same conditions, but without a previous non-electrochemical exposure phase.

Examples 15 to 65

One of the materials previously described is electrochemically treated in the solution shown in the following table. The conditions are also shown in the table.

Example 66

• 2,00 Gew.-Teile eines Styrol/Maleinsäureanhydrid-Mischpolymerisates (1:1, Molekulargewicht 50000), welches mit Hydroxyethylmethacrylat umgesetzt ist
• 2,00 Gew.-Teile eines Diurethans aus 2 Mol Glycerindimethylacrylat und 1 Mol Hexamethylendiisocyanat
• 0,70 Gew.-Teile 9-Phenyl-acridin
• 0,07 Gew.-Teile Samaronmarineblau
• 32,00 Gew.-Teile Butanon
• 12,00 Gew.-Teile Essigsäurebutylester
• 12,00 Gew.-Teile Ethylenglykolmonomethylether

An electrochemically roughened, anodized aluminum foil which has been hydrophilized with an aqueous polyvinylphosphonic acid solution is coated with the following negative-working light-sensitive solution:

• 2.00 parts by weight of a styrene / maleic anhydride copolymer (1: 1, molecular weight 50,000), which is reacted with hydroxyethyl methacrylate
• 2.00 parts by weight of a diurethane from 2 moles of glycerol dimethyl acrylate and 1 mole of hexamethylene diisocyanate
• 0.70 parts by weight 9-phenyl acridine
• 0.07 part by weight of Samaron navy blue
• 32.00 parts by weight of butanone
• 12.00 parts by weight of butyl acetate
• 12.00 parts by weight of ethylene glycol monomethyl ether

After drying, the electrochemical treatment is carried out in an aqueous solution containing 3% ammonium sulfate and 1% sodium octyl sulfate at a pH of 4 and at about 40 V.

Example 67

The plate of Example 66 is electrochemically treated in an aqueous solution containing 3% sodium nitrate and 3% ethoxylated isotridecyl alcohol with 8 ethylene oxide units at a pH of 4.

Example 68

• 10,00 Gew.-Teile 2,5-Bis-(4'-diethylaminophenyl)-1,3,4- oxdiazol
• 10,00 Gew.-Teile eines Mischpolymerisats aus Styrol und Maleinsäureanhydrid (mit einem Erweichungspunkt von 210°C)
• 0,02 Gew.-Teile Rhodamin FB (C. I. 45170)
• 300,00 Gew.-Teile Ethylenglykolmonomethylether.

An electrochemically roughened and anodized aluminum foil is coated with an electrophotographically working solution consisting of the following components:

• 10.00 parts by weight of 2,5-bis (4'-diethylaminophenyl) -1,3,4-oxdiazole
• 10.00 parts by weight of a copolymer of styrene and maleic anhydride (with a softening point of 210 ° C.)
• 0.02 part by weight of Rhodamine FB (CI 45170)
• 300.00 parts by weight of ethylene glycol monomethyl ether.

The imagewise stripping takes place electrochemically in an aqueous solution containing 3% ammonium phosphate and 3% of an ethoxylated isotridecyl alcohol with 8 ethylene oxide units at a pH of 8.

Example 69

• 0,25 Gew.-Teile Polyvinylacetat (Viskosität von 2200 mPa·s nach Höppler in 20 %iger Essigsäureethylester-Lösung bei 20°C)
• 0,75 Gew.-Teile Polyvinylacetat (40 mPa·s)
• 4,00 Gew.-Teile Phenol-Formaldehyd-Novolak (Erweichungspunkt von 110° bis 120°C nach DIN 53 181)
• 1,00 Gew.-Teile Kondensationsprodukt aus Cyclohexanon und Formaldehyd (Erweichungspunkt von 75° bis 90°C)
• 3,00 Gew.-Teile 4-(2-Phenyl-prop-2-yl)-phenylester der Naphthochinon-(1,2)-diazid-(2)-sulfonsäure-(4)
• 0,20 Gew.-Teile Kristallviolett
• 88,80 Gew.-Teile Ethylenglykol
• 2,00 Gew.-Teile dest. H₂0

und kann in einer wäßriger Lösung mit einem Gehalt an 3 % Lithiumsulfat und 1 % Natrium-octylsulfat bei einem pH-Wert von 3 elektrochemisch behandelt werden.A chrome-plated copper foil is coated with the following negative working, light-sensitive solution:

• 0.25 part by weight of polyvinyl acetate (viscosity of 2200 mPas according to Höppler in 20% ethyl acetate solution at 20 ° C)
• 0.75 part by weight of polyvinyl acetate (40 mPas)
• 4.00 parts by weight of phenol-formaldehyde novolak (softening point from 110 ° to 120 ° C according to DIN 53 181)
• 1.00 parts by weight of condensation product from cyclohexanone and formaldehyde (softening point from 75 ° to 90 ° C)
• 3.00 parts by weight of 4- (2-phenyl-prop-2-yl) -phenyl ester of naphthoquinone- (1,2) -diazide- (2) -sulfonic acid- (4)
• 0.20 parts by weight of crystal violet
• 88.80 parts by weight of ethylene glycol
• 2.00 parts by weight of dist. H ₂ 0

and can be electrochemically treated in an aqueous solution containing 3% lithium sulfate and 1% sodium octyl sulfate at pH 3.

Example 70

• 4 Gew.-Teile eines Kresol-Formaldehyd-Novolaks (Schmelzbereich 105° - 120°C nach DIN 53 181)
• 1 Gew.-Teil Bis-naphthochinon-1,2-diazid-5-sulfonsäureester des 4,4'-Bishydroxyphenylvalerian- säure-2-ethoxyethylesters
• 40 Gew.-Teile Methylethylketon

A dry brushed aluminum foil is provided with a liquid photoresist layer consisting of the following components:

• 4 parts by weight of a cresol-formaldehyde novolak (melting range 105 ° - 120 ° C according to DIN 53 181)
• 1 part by weight of bis-naphthoquinone-1,2-diazide-5-sulfonic acid ester of 4,4'-bishydroxyphenylvaleric acid 2-ethoxyethyl ester
• 40 parts by weight of methyl ethyl ketone

After drying, the electrochemical treatment is carried out in an aqueous solution containing 3% lithium sulfate and 1% sodium octyl sulfate at a pH of 3.

Examples 71-102

One of the materials previously described is electrochemically treated in the solution shown in the following table. The conditions are also shown in the table.

Claims (7)

1. A method for electrochemical imaging on a multilayer sheet material with at least one electrically conductive layer by the action of electrical current via at least one needle-shaped electrode, characterized in that a) the multilayer sheet material has a reproduction layer which may contain at least one radiation-sensitive compound, b) at least one needle-shaped electrode acts from the side of the multilayer sheet material which carries the reproduction layer, and c) both the electrode (s) and the multilayer sheet material are arranged in interaction with an aqueous electrolyte solution. 2. The method according to claim 1, characterized in that the pH of the aqueous electrolyte solution is in the range from 2.0 to 10.0. 3. The method according to claim 1 or 2, characterized in that the aqueous electrolyte solution contains at least one salt of an organic or inorganic acid in a concentration of 0.1% by weight up to the saturation limit of the solution on the respective salt. 4. The method according to any one of claims 1 to 3, characterized characterized in that the aqueous electrolyte solution contains a surfactant in a concentration of 0.1 to 5 wt .-%. 5. The method according to any one of claims 1 to 4, characterized in that the electrochemical treatment is carried out with a direct or alternating current with a current density of 1 to 100 A / dm and at a temperature of 20 ° to 70 ° C. 6. The method according to any one of claims 1 to 5, characterized in that the reproduction layer contains at least one radiation-sensitive compound and is present as part of an offset printing plate or as a photoresist applied to a carrier material. 7. The method according to claim 6, characterized in that the reproduction layer is a positive-working layer.