DE2517812A1 - METHOD OF MANUFACTURING PRINTING PLATE CARRIERS FROM ALUMINUM - Google Patents

Description

PATENT LAWYERS ^. GRÜNECKER

DlF ¹ L -INQ.

H. KINKELDEY

DR.-INQ.

W. STOCKMAIR

DR.-INQ. AeE (OALTECH)

K. SCHUMANN

DR. REH. NAT. · DIPL.-PHYS.

P. H. JAKOB

DlPl INQ.

G. BEZOLD

DR. RER. NAT. ■ DIPU.-CHEM.

MUNICH E. K. WEIL

FUJI PHOTO PILM CO., LTD. ' ^{DR RER OEC ΙΝβ} No. 210, Nakanuma, - ■ Lindau

Mlnauii Ashigara-Shi, _{8 MUNICH 22} Kanagawa, Japan maximiuanstrasse ₄₃

April 22, 1975 P 9132-GVku

Process for the production of printing plate supports made of aluminum

The invention relates to a method for producing printing plate supports made of aluminum.

Aluminum is widely used as a carrier for printing plates, especially planographic printing plates, because it is easy to is cheap, easy to process and dimensionally stable. Undergoes an aluminum sheet of anodic oxidation in a suitable electrolyte, such as sulfuric acid, chromic acid, Oxalic acid or phosphoric acid, an aluminum oxide layer forms on the surface of the aluminum sheet. Since the alumina layer has a number of fine pores, it has high water absorbency and possesses excellent abrasion resistance. Nevertheless, aluminum supports having an anodic oxide layer have hitherto been used No application found for the production of flat printing plates, since light-sensitive coating compounds are poor adhere to the aluminum oxide and ^ due to the interaction

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TELEPHONE (089) 232082 TELEX O5-2938O TELESPiAMME MONAPAT

between the alumina and the photosensitive Layer, its sensitivity, developability and stability will be compromised over time. For these reasons, it has been difficult for the Planographic printing processes use aluminum plates that have an anodic oxide layer with high water absorption capacity and have good abrasion resistance.

To overcome these difficulties have already been various procedures proposed. For example, U.S. Patent No. 3,511,661 shows one suitable for planographic printing Aluminum carrier known on which an anodic oxide layer is produced by electrolysis in phosphoric acid has been. Such anodic oxide layers obtained by electrolysis in phosphoric acid have excellent properties Adhesiveness for photosensitive compositions, but their abrasion resistance is suitable for use as a carrier too low in planographic printing. The anodic oxidation in phosphoric acid also has the technical part that due to the low conductivity of phosphoric acid very high voltages are required. In addition, phosphoric acid is expensive and dangerous to use due to the high voltage used.

Anodic oxide layers can also be produced on aluminum plates by electrolysis in sulfuric acid, however Although this economically advantageous process produces coatings with good abrasion resistance, the panels are nevertheless not suitable as a carrier for the planographic printing process. Light-sensitive materials, for example, do not adhere well on the aluminum plate, furthermore, the anodic oxide layer absorbs moisture from the air, so that the pores clogged and the properties of the layer surface are changed over time.

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From DT-OS 2 251 710 and BE-PS 797 180 is a Process for the production of carrier plates for the flat printing process described, in which the adhesion light-sensitive materials on the layer surface and the stability of the layer can be improved by removing the anodic oxide layer produced in sulfuric acid treated with phosphoric acid on the aluminum plate. However, the process is slow and not very efficient perform. The use of the expensive phosphoric acid also makes the process unsuitable for mass production. Further, the properties of the layer surface are determined by the aluminum ion concentration in the phosphoric acid treatment solution influenced, so that carriers with certain properties are difficult to produce in a targeted manner permit.

The object of the invention is therefore to provide a new method for Manufacture of cheap printing plate supports, which in addition to good adhesion for photosensitive Coating compositions have excellent abrasion resistance and a surface with largely hydrophilic properties.

The invention relates to a method for the production of printing plate supports made of aluminum, which is characterized is that on the surface of a plate made of aluminum or an aluminum alloy, an anodic Oxide layer generated and this either with a basic solution or with at least one egg and / or Dibasic acid-containing solution treated, so that about 5 to 70 percent by weight of the oxide layer is removed again will. If necessary, the plate can then be used Further surface treatment can be used to improve the hydrophilic properties.

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The aluminum plates used in the method of the invention consist, for example, of pure aluminum or aluminum alloys. Suitable alloy components are e.g. silicon, copper, manganese, magnesium, chromium, zinc, lead, Bismuth and nickel. Special aluminum alloys are listed in the following table. The amount of the alloy components is given in percent by weight, the best is aluminum.

aluminum Si Cu Mn Mg Cr Zn alloy 0.4 - - 0.6 - - 2S - - 1.2 - - - 3S - 4.5 0.6 - - 24S - - - 2.5 0.25 - 52S 0.6 0.25 - 1.0 0.25 - 61S - 1.60 - 2.50 0.30 5.60 75S

The alloys can still contain negligible amounts of impurities as well as iron or titanium.

Since the surface of the aluminum plates is contaminated with e.g. fats and oils, rust and dust, it must e.g. 'Chemical route, for example with the help of a solvent or a lye, e.g. according to the one in "Einzoku Hyomen Gizyutsu Binran "(Handbook of Metal Surface Technology), JYikkan Kogyo Shimbun, p. 186 to 210 described method can be degreased and cleaned. The plate can then optionally still be roughened, e.g. by blasting with glass beads, coarse sand, fine sand or brushing after the process the JA-OS 33 411/1973 or by electrolytic

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Eauhen according to the procedure of JA-AS 28 123/1973 and of GB-PS 896 563 can be further cleaned. This roughening treatment is not absolutely necessary, but sandblasted planographic printing plates have a higher one Water absorption capacity as plates with a smooth surface and give good prints. The rough. can optionally Another treatment with an aluminum etching solution can be followed to remove the non-image areas of dirt to free, as described in JA-OS 49 501/1973 is.

Aqueous solutions, for example, are suitable as additive solutions for aluminum Solutions of sodium hydroxide, potassium hydroxide, sodium triphosphate, Sodium aluminate, mixtures of sodium silicate and the alkalis mentioned and mixtures of sodium carbonate and the alkalis mentioned. The aluminum plate is usually treated for 10 seconds to 30 minutes at a liquid temperature of 50 to 90 C in I bis 20 percent strength by weight aqueous solutions of the alkalis mentioned. The etching treatment is not absolutely necessary, however, it is preferably used when the photosensitive coating material tends to be in the non-image areas to stick.

Aluminum plates which, after chemical cleaning or bonding, an Itz treatment according to JA-OS 49 501/1973 are preferably in 70% nitric acid dipped to get a cleaner aluminum surface.

An oxide layer is then produced by anodic oxidation on the aluminum plate treated in this way. As an electrolyte are suitable in the method of the invention, e.g. aqueous or non-aqueous solutions of phosphoric acid, chromic acid,

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Oxalic acid, sulfamic acid, sulfuric acid, benzenesulfonic acid or mixtures of two or more of these acids. The anodic oxide layer is created on the aluminum surface by switching the aluminum plate as an anode and passing a current through the electrolyte. The electrolysis conditions depend primarily on the type of electrolyte used. The electrolyte concentration is usually about 1 to 80 percent by weight, the bath temperature about 5 "to 70 ^° C., the current density about 0.5 to A / dm, the voltage about 1 to 100 volts and the electrolysis time about 30 seconds to 50 minutes The preferred electrolysis conditions are listed below:

electrolyte Electrical
lysis
focus
tration
(Wt. -90 Electrical
lysis
tempe-
rature Current density
(A / dm ² ) tension
(Volt) Electric
lysis time
(min) sulfur
acid
Oxalic acid
phosphorus
acid
Chromic acid OO OO
IN-CVI VD KN
Il Il
vv CM CM 5-65
20-60
20-60
30-60 0.5-30
0.5-20
0.5-20
0.5-10 1-50
10-70
10-60
10-60 1-30
5-40
1-30
"1-50

The properties of the anodic oxide layer obtained depend on the electrolyte used and the other electrolysis conditions. In J. Electrochem. Soc, Vol. 9 (1953) » P. 415 to 419 is e.g. the dependence of the pore diameter or the number of pores of the anodic oxide layer obtained from the electrolyte used and the electrolysis conditions described:

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Table 1

electrolyte bath
tempera
door
(° C) Bath-
span
tion
(V) Pores
by
knife Pores
number
(x 10 ⁹ / m ² ) 4% 24 20th 330 121 Phosphoric acid 40 50 60 2? 2 % 24 20th 170 230 Oxalic acid 40 75 60 37 3% 38 20th 240 140 Chromic acid 40 52 60 27 15% 10 15th 120 498 sulfuric acid 20th 334 30th 179

The basic solutions used in the process of the invention are usually aqueous solutions of basic substances are used, but solutions in other solvents can also be used be used. Any water-miscible solvents are suitable for this purpose, but with hydroxyl groups containing organic solvents, such as methanol, ethanol, or glycol monomethyl ether, are preferred. The pH of the Ba-'sic Solution is, for example, above about 10 and preferably above about 11. Suitable basic compounds are e.g. Hydroxides, salts of strong bases with weak acids and compounds containing amino groups and their mixtures. Specific examples are sodium hydroxide, potassium hydroxide, lithium hydroxide, barium hydroxide, calcium hydroxide, magnesium hydroxide, Sodium aluminate, sodium triphosphate, sodium diphosphate, Potassium triphosphate, potassium diphosphate, sodium carbonate, Sodium silicate, sodium acetate, ammonia, triethanolamine,

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Diethanolamine, monoethanolamine, morpholine or their mixtures. The treatment solution can also e.g. Metal salts or scale inhibitors, each in an amount of, for example, from 0 to about 5 percent by weight, or surfactants, e.g., in an amount from 0 to about 0.5 weight percent.

The treatment with the basic solutions mentioned takes place under conditions that depend, among other things, on the electrolyte used to produce the anodic oxide layer and the specific basic treatment solution. In general, the concentration of the basic solution is about 0.1 to 80 percent by weight, preferably about 1 to 50 percent by weight, the treatment temperature about 5 to 95 ° C., preferably about 15 to 70 ^° C., and the treatment time about 1 second to 10 minutes, preferably about 2 seconds to 5 minutes.

For the preparation of solutions of monobasic and / or dibasic acids one usually uses water, but it is also possible to use water other solvents can be used. Any solvents miscible with water are suitable for this purpose, whereby Organic solvents containing hydroxyl groups], such as Methanol, ethanol or glycol monomethyl ether are preferred. For example, the pH of the acid solutions is below about 2, preferably below about 1.5- Suitable monobasic acids are e.g. hydrochloric acid, hypochlorous acid, hypobromous acid, hypoiodous acid, chlorous acid, bromous acid, iodine Acid, bromic acid, iodic acid, hydrofluoric acid, permanganic acid, Nitric acid, acetic acid, perchloric acid, formic acid and chloric acid. Suitable dibasic acids are e.g. sulfuric acid, Oxalic acid, chromic acid, carbonic acid, sulphurous acid, silicic acid and fluorozirconic acid. These acids can either as such or as mixtures of two or more

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Acids applied. The treatment solutions can in addition, for example, metal salts, anti-scaling agents or surfactants in the above mentioned concentrations.

The conditions used in the treatment with solutions of monobasic and / or dibasic acids depend on the type of electrolyte used to produce the anodic oxide layer and the acids used in each case. In general, however, the acid concentration is about 0.5 to 100 weight percent, preferably about 1 to 50 percent by weight, the treatment temperature is about 10 to 95 ° C, preferably about 15 to 80 ⁰ C, and the treatment time from about 1 second to 10 minutes, preferably about 2 seconds to 5 minutes.

The treatment can be carried out in any way, in which case the anodic oxide layer must be brought into contact with the treatment solution mentioned. This can be done e.g. Spraying the treatment solution onto the anodic oxide layer by dipping the one provided with the anodic oxide layer Aluminum in the treatment solution or by applying the treatment solution to the anodic oxide layer. the Dipping method is preferred here in terms of uniform and effective treatment.

In this way, the anodic oxide layer on the carrier can be partially removed. An aluminum support for planographic printing plates, whose anodic oxide layer has excellent adhesiveness to photosensitive agents, arises especially when you add about 5 to 70 percent by weight, preferably about 10 to 50 percent by weight, des Total weight of the anodic oxide layer removes. When removing greater than about 70 percent by weight of the anodic

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Oxide layer loses its characteristic hardness, so that the carrier obtained in this way is no longer suitable for use in the planographic printing process. On the other hand, lets if less than about 5 percent by weight of the anodic oxide layer is removed, no significant effect is achieved.

Preferred treatment solutions for the anodic oxide layer of aluminum are basic solutions, in particular of sodium hydroxide, potassium hydroxide, sodium carbonate and sodium triphosphate.

Since the surface of the aluminum plates treated according to the invention has a high water absorption capacity and good adhesiveness opposed to light-sensitive agents, the plates can be used directly as supports in printing processes. If necessary, however, a further surface treatment can also be added. For treating the surface e.g. aqueous solutions of alkali metal silicates such as sodium silicate, potassium fluorozirconate or Phosphoric acid glasses; See U.S. Patents 3,181,461, 2,714,066 and 2 946 683. Furthermore, for example, Grurx jacket coatings made of hydrophilic Polymers are applied, e.g. from polyvinylbenzenesulfonic acid, Polyacrylic acid, carboxymethyl cellulose, polyacrylamide, polyvinyl alcohol, polyvinylpyrrolidone or polyethylene-halein, acid anhydride copolymers. Solutions of the hydrophilic polymers in, for example, are suitable for applying these coatings Water, organic solvents or their mixtures. Suitable organic solvents are, for example, alcohols, such as Methanol, ethanol or propanol, ketones such as acetone and methyl ethyl ketone, glycol monoethers and monoether esters such as Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene glycol monomethyl ether acetate, dimethylformamide and dimethyl sulfoxide. Organic solvents with a

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Water contents from 0 "to 50 percent by volume are preferred. The hydrophilic polymers are preferably in one

Amount of about 5 to 150 mg / m applied. The different Surface treatment methods can be used individually or used in combination.

As photosensitive compositions for coating the inventive Printing plate supports are, for example, organic or inorganic light-sensitive agents, light-sensitive ones Synthetic resins as well as the photoresists previously used for plate production, which polymerize during exposure, crosslink, dimerize, depolymerize or decompose and their solubilities change in the process. Specific Examples of such photosensitive agents are:

1. masses with a content of light-sensitive iron (III) salts, which supply iron (II) ions when exposed to light, such as ammonium iron citrate, ammonium iron oxalate and sodium iron oxalate, as well as hydrophilic polymers such as gelatin and glue.

2. Masses with a content of hydrophilic polymers, such as gelatin, isinglass, gum arabic, polyvinyl alcohol, Polyacrylamide, carboxymethyl cellulose, hydroxyethyl cellulose or ■ polyvinyl methyl ether-maleic anhydride copolymers, and tetrazonium salts of diamino compounds such as p-aminodiphenylamine, benzidine, dianisidine and toluidine, or a diazo resin produced by the condensation of p-diazodiphenylamine and paraformaldehyde has been.

3. Masses with a content of diazo resin which is produced by condensation a diazo compound such as p-diazodiphenylamine and paraformaldehyde; see US-PS

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649 373, 3 046 121, 3 046 122 and 3 046 123.

* ■. Compositions containing azides, such as sodium 4,4'-diazidostirbene-2,2'-disulfonate, sodium 1,5-diazidonaphthalene-3,7-disulfonate, sodium 3'-azido-4-azidobenzalacetophenone-2 sulfonate, sodium 4,4 ¹ -diazidostilbene-cC-carbonate, sodium-di- (4-azido-2'-hydroxybenzal) -acetone-2-sulfonate, sodium-4-azidobenzalacetophenone-2-sulfonate and sodium 4,4'-diazidodiphenyl-3,3'-disulfonate and polymers such as polyacrylamide, polyvinylpyrrolidone, polyacrylic acid, gelatin, casein, albumin, gum arabic, carboxymethyl cellulose, hydroxyethyl cellulose or soluble nylon.

5. masses containing azides, such as 4,4'-diazidostilbene, 4,4'-diazidochalcone or 4,4'-diazidodibenzalacetone, cyclized rubber, synthetic rubber or organic soluble polymers.

6. Compositions containing quinonediazides, such as naphthoquinone-1,2-diazidosulfonic acid or their esters, as well as alkali-soluble synthetic resins.

7. Compounds which dimerize when exposed to actinic radiation, such as polyvinyl cinnamate, polyvinyl cinnamoyl ethyl ether. _t Polyethylcinnamate-acrylate and its copolymers, polyethylcinnamate-methacrylate and its copolymers, poly-p-vinylphenylcinnamate and its copolymers, polyvinylbenzalacetophenone and its derivatives, polyvinylcinnamylidene acetate and its derivatives, acrylic acid-allyl prepolymers, and also derivatives of acrylic acid-allyl prepolymers of polyesters and its derivatives Polyalcohols; See, for example, U.S. Patent 3,030,208.

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8. Compounds that act on irradiation with actinic Polymerize radiation, such as that disclosed in U.S. Patent 2,760 and 5,060,025 known compounds having two or more terminal ethylene groups, such as ethylene glycol diacrylate and dimethacrylate, propylene glycol diacrylate and dimethacrylate, diethylene glycol diacrylate and dimethacrylate, Triethylene glycol diacrylate and dimethacrylate, dipropylene glycol diacrylate and dimethacrylate, trimethylol ethane triacrylate and trimethacrylate, trimethylol propane triacrylate and trimethacrylate, tetramethylol methane tetraacrylate and tetramethacrylate, methylenebisacrylamide and 1,6-hexamethylene bisacrylamide.

The above compounds which dimerize or polymerize on exposure to actinic radiation can optionally, for example, with binders, sensitizers, thermal polymerization inhibitors, colorants or Add plasticizers to ground. Suitable binders are, for example, in addition to those described in JA-AS 8 495/1960 and 5 095/1970 Compounds including vinyl ester polymers and copolymers, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyrate, Polyvinyl acetate, such as polyvinyl butyral and polyvinyl formal, and alkyd resins such as saturated or unsaturated polyglycerol phthalates and polyglycerol maleates. Such Synthetic resins, for example, facilitate the flowability of light-sensitive, sensitive Hating and thus processing them into thin layers «

Sensitizers suitable for the purposes of the invention are described, for example, in U.S. Patents 2,610,120, 2,6-0,285, 2,670,286, 2,670,287, 2 690 966, 2 752 501, 2 855 656, 2 956 878, 5 025 100, 5 066 117, 5 141 770, 5 175 787, 5 557 8J1, 5 409 595, 5 418 295, 5 455 110, 5 475 617, 5 561 969, 5 575 929, 5 582 527, 5 647 470, 5 721 566 and 5 757 519.

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Preferred sensitizers here are, for example, anthracene, phenanthrene, chrysene, o-nitroanisole, (i-nitro styrene, p-nitrodiphenyl-5-fiiro-2-aminotoluene, 4-nitroaniline, 2,4,6-trinitroaniline, 4-l-nitro-2 -chloraniline, anthrone, 1-cyano-2-keto-J-methyl-G-bromo-J-azobenzanthrone, 2-keto-3-methyl-1,3-diazobenzanthrone, 1,2-benzanthraquinone, ß-chloroanthraquinone, dibenzalacetone , Malachite green, benzoin, benzoin methyl ether, benzoin ethyl ether, 9,10-inthraquinone, 1-chloroanthraquinone, 9j10-phenanthraquinone, leuko-triphenylmethane, 2-benzoylmethylene-1-methyl-ß-naphthothiazoline, ^ - ^ itrochinaphthene, 1, 2-benzalanthraquinone, ρ, ρ'-tetraethyldiaminodiphenyl ketone, ρ, ρ'-dimethylaminobenzophenone and ^z ^ -l! Titro-2-chloroaniline. The sensitizer is preferably used in an amount of about 0.5 to 15 weight percent, in particular about 2 to β percent by weight, based on the weight of the dimerizing or polymerizing compound, is used.

Preferred colorants are, for example, pigments such as merocyanine blue (CI. 74160), Carmine 6B (CI. 15850) and Ehodamin B Lake (CI. 4517Ο), as well as dyes such as Oilblue BO (CI. 7 ^ 350). The amount of colorant used depends, for example, on the amount of coating material, but is generally about 1 to 50 percent by weight, preferably about 2 to 15 percent by weight, of the photosensitive agent.

As the plasticizer suitable, for example phthalic esters such as dibutyl phthalate, diheptyl phthalate and dioctyl phthalate _r Glykolester as Glykoläthylphthalyläthylester, Glykolbutylphthalylbutylester and Dicaprinsäuretriäthylenglykolester, aliphatic dicarboxylic acid esters such as dioctyl adipate, diisopropyl adipate, dibutyl sebacate and dioctyl azelate, organophosphate, as sphat Tributylpho, tri (chi or ethyl) phosphate, Tricresyl phosphate and i-triphenyl phosphate. The plasticizer is usually

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wise in an amount of about 5 "to 60 percent by weight, preferably about 15 to 40 percent by weight of the photosensitive Applied by means "

Colorants may optionally be added to the photosensitive agent to improve printability, with spiropyrans being preferred. Specific examples of such coloring agents are 6'-nitro-1,3,3-trimethyl-spiro (indoline-2,2 '-2' H-chromene), 8 '-formyl-1,3,3-trimethyl-spiro (indoline-2 , 2'-2'H-chromene), 6 ¹ , 8'-dichloro-1,3,3-trimethylspiro- (indoline-2,2 '-2' H-chromene and 8'-methoxy-6 '-nitro -1,3,3-trimethylspiro (indoline-2,2'-2'H-chromene) The colorant is usually used in an amount of about 0.5 to 20 percent, preferably about 1 to 8 percent, by weight of the photosensitive agent .

Furthermore, the photosensitive layer can also contain polymerization inhibitors, such as hydroquinone, p-methoxyphenol and 4,4'-thiobis (3-methyl-6-tert-butylphenol) can be added.

Of the above-mentioned photosensitive agents, the agents of classes 4, 7 and 8 are preferred, the compounds Classes 7 and 8 are particularly preferred.

In general, the photosensitive agents are dissolved in water and / or organic solvents, based on the invention produced carrier applied and dried, whereby a photosensitive planographic printing plate is formed.

The photosensitive agent is usually used in an amount of about 0.1 to 3 * 5 g / m, preferably about 0.5 to

2.5 g / m ·> applied. The photosensitive planographic printing plates coated in this way are exposed imagewise to a suitable radiation source, for example a carbon arc, a xenon lamp, a mercury lamp, a volfram lamp

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or a metal halide lamp, and then developed. If the planographic printing plate is to be used as an It intaglio printing plate, the entire plate surface is coated with a varnish after the imagewise exposure and development, and the varnish is then removed again in the image areas.

Since the planographic printing plate carrier produced according to the invention have excellent adhesiveness for photosensitive agents and good abrasion resistance, they are at Can be used in flat printing machines for a long time. In addition, the inventive method has the advantage that it is cheap to carry out and little of the aluminum ion concentration in the removal of the anodic oxide layer used treatment solution is influenced.

The examples illustrate the invention. All parts, percentages and ratios are by weight if nothing other is indicated.

Examples 1 to 3

One after the one in JA-OS 33 411/1973 with the help of a brush and sand roughened aluminum 2S plate is used for 20 seconds 55 ° C immersed in a 10% aqueous sodium hydroxide solution and then flushed. The aluminum surface obtained has a gray hue. Then you immerse the aluminum plate GO seconds "at room temperature (20 ° C) in 70% nitric acid and rinse then, creating a bright aluminum surface. With the obtained aluminum plate as the anode and lead as the cathode is then electrolysed for 3 minutes in 20% sulfuric acid at 30 C and a direct current density of 2 A / dm

anodic oxide layer (3.0 g / m) generated. The plates produced in this way are used in the following experiments. About half of the aluminum plate is immersed in a

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trium hydroxide, sodium triphosphate or sodium aluminate containing aqueous solution and treated under the conditions given in Table 2. For comparison, will a plate treated with phosphoric acid. The numbers in brackets mean the treatment time (see).

Table 2

Example treatment
solution Tempe
rature Percentage removed
anodic oxide layer 33.3 % 50.0 % d. 1 2% sodium
hydroxide 20th 16.7% (26) (40) 66.7? * 2 2 % sodium
triphos
phat 40 (12) (28) (42) (52) 3 sodium aluminum
nat (20 % NaOH;
7 % Al) 25th (16) (10) (16) (56) Comparison
example (6) (20) 1 5% phosphorus
acid 60 (45) (70) 2 5% phosphorus
acid' 40 (24) - - (92) - - (^ 150)

The results show that at low temperatures and low concentrations with basic solutions much higher Treatment speeds can be achieved than in the known treatment with phosphoric acid.

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The photosensitive mixture of an ester of an acetone-pyrogallol condensate and naphthoquinonediazide (2) -5-sulfonic acid described in Example 1 of JA-AS 28 403/1968 is then applied to each of the aluminum plates treated above with the aid of a centrifugal disk and then applied for 2 minutes dried at 100 ^{° C.} The amount of coating is 2.5 g / m ² .

Amount (g) ester from acetone-pyrogallol condensate

5.0

Naphthoquinonediazide (2) -5-sulfonic acid m-cresol-formaldehyde resin (average molecular weight: 2500) * 10.0

Oil Blue (CI. 74-350) 0.01

Methyl ethyl ketone 70.0

Amyl acetate 65.0

The planographic printing plate obtained is exposed with KLIfe of a 30 A carbon sheet for 40 seconds at a distance of 70 cm through an original positive. Then dipping the plate for 1 min at 30 ⁰ C in a 3% aqueous Katriumsilikatlösung and then developing the plate by gently rubbing the surface with an absorbent cotton fabric with a 3% aqueous sodium silicate solution is impregnated. The planographic printing plate obtained, 16.7% of the anodic oxide layer of which has been removed, is installed in a printing machine (Multilith 1250) and used for printing. In the areas not subjected to the treatment of! Table 2, 5% of the

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Halftone dots already from the thirty thousandth sheet of paper, while with the printing plate produced according to the invention the same print quality is achieved with the eighty thousandth sheet of paper as at the beginning. Similar results are obtained with carriers in which 33.3%, 50 % and 66.7% of the anodic oxide layer have been removed, respectively.

Beismele 4 to 6

Example 1 a roughened according Aluminium2S plate is immersed for 30 seconds at 40 ⁰ C in a 10% aqueous sodium hydroxide solution and then rinsed. A gray aluminum surface is obtained. The aluminum plate is then immersed in 70% concentrated nitric acid at room temperature (20 ° C.) for 60 seconds. A light aluminum surface is created. With the aluminum plate obtained as the anode and a stainless steel cathode, electrolysis is then carried out for 3 minutes at 30 ° C. in 20% strength sulfuric acid with a current density of 2.5 A / dm *. An aluminum plate with an anodic oxide layer (3.5 g / m 2) is obtained, one half of which is subjected to the following treatment:

Table 3

example 2% Treatment
solution tempera-
door ( ⁶ C) Percentage removed
d. anodic oxide layer 33.3 % 50.0 % 66.7 % 2% 16.7% (26) (40) (52) 4th sodium
hydroxide 20th (12) (28) (42) (56) VJl Sodium-
triphosphate 40 (16) (10) (16) (20) 6th Sodium aluminate
(25 " % NaOH; 7% Al ) 25 (6)

The numbers in brackets indicate the diving times (see).

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Each of the aluminum plates is then heated to 65 ° C for 20 seconds into an aqueous sodium silicate solution of the following composition dipped and then rinsed.

Amount (g)

40 % aqueous sodium silicate solution 250

Water 4000.

With the help of a centrifugal disc, 100 ml / m 2 of the following solution are used as a primer at barely any temperature applied to the plates and then dried.

Polyynyl pyrrolidone ("K-90", the General

Aniline & Film Corporation) 0.5 g

Methanol 1000 ml

The following photosensitive mixture is then applied with the aid of a centrifugal disk and dried for 2 minutes at 100 ^° C.

Amount (g)

Condensate from 1,4-di-ß-hydroxyethoxy-

cyclohexane and p-phenylenediacrylic acid 10.0

(average molecular weight: 8000)

5-nitroacenaphthene 1.0

Dibutyl phthalate. 4.0

Phthalocyanine Blue 2.0

Monochlorobenzene 300

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The amount of coating is 1.7 g / m »based on the Dry weight. The resulting photosensitive planographic printing plate is then exposed to a JO A arc lamp for 30 seconds exposed through an original negative at a distance of 70 cm. Then one develops by lightly rubbing the surface with an absorbent cotton fabric, the is soaked with the following developer.

Amount (ml)

4-2T-butyrolactone 1000

Glycerin 100

Methyl abietate 10

hydrogenated tree resin ("Stabelite Resin")

Hercules Powder Co.) 1

"Zonyl A" wetting agent from DuPont) 10.2

distilled water 100

85 % phosphoric acid 25

Dissolve in the areas not treated according to the invention During development, the image areas can be removed from the aluminum surface by lightly rubbing the cotton fabric away. In contrast, the image areas on the surface treated according to the invention can be removed even with strong Do not rub off the aluminum surface during development. The printing plate carrier treated according to Table 3 is finally installed in a printing machine (Multilith 1250) and used for printing. Also at eighty thousandth sheet of paper you can still achieve the same print quality as at the beginning.

Examples 7 and 8

With a roughened aluminum plate of Example 1 as an anode and as a cathode lead is an electrolysis for 4 minutes at 54 ⁰ C in a v / ässrigen solution of 0.25 mol / l oxalic acid

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and 0.25 mol / l potassium oxalate having a direct current density performed by 2 i / dm. An anodic oxide layer is created (3.2 g / m). The aluminum plate obtained is then treated under the conditions shown in Table 4. The Numbers in brackets indicate dive times (see).

Table 4

Example treatment
solution tempera
tur ( ⁰ C) Percentage removed
d. anodic oxide layer 33% 50% 67 % 7 2% sodium
hydroxide
8 2% matrium
tripho sphat .20
40 13% (80)
(81) (124)
(125) (178)
(171) (38)
(38)

The aluminum plate obtained is then treated according to Example 4 with sodium silicate, with a primer and a photosensitive mixture coated, exposed and finally developed.

Areas not treated with an aqueous sodium hydroxide or sodium triphosphate solution will peel , the image areas during development, while they adhere firmly and in the areas treated according to the invention are strongly pronounced.

The printing plate carrier treated according to the invention is installed in a printing machine (Multilith 1250) and used for Printing used. Even with the forty thousandth sheet, the same print quality is achieved as at the beginning.

509844/1021

Examples 9 and 10

The photosensitive mixture from Example 1 is applied to one treated by the method of Examples 7 and 8 Aluminum plate applied and dried. The photosensitive planographic printing plate obtained is then made according to Example 1 exposed and developed. In the not with a watery one Sodium hydroxide or sodium triphosphate solution treated In areas, the image areas come off during development, while they are in the areas treated according to the invention are not damaged even when rubbing vigorously with a cotton cloth soaked in water.

Examples 11 and 12

With an aluminum 2S plate roughened according to Example 1 electrolysis is carried out for 10 minutes in a 3% aqueous chromic acid solution at 38 ° C. as the anode and lead as the cathode

ο
carried out with a current density of 1 A / dm. An anodic oxide layer is created (3.5 g / m). About half of the aluminum plate obtained is subjected to a treatment under the conditions specified in Table 5 and then treated in accordance with Example 4 with sodium silicate, coated with a primer and a photosensitive mixture, exposed and finally developed. The numbers in brackets indicate the diving times (see).

Table 5

Example treatment
solution "Tempe
rature
CG) Percentage removed
the anodic oxide layer 27% 46 % 67.5% 11 2% sodium
hydroxide
12 2% sodium
aluminate (25%
NaOH, 7% Al) 40
25th 13% (310)
(185) (461)
(281) (623)
(375) : 155)
: 93)

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In those not with a drip-filled sodium triphosphate or sodium aluminate solution on treated areas the image areas can only be removed by vigorous rubbing, while in the areas treated according to the invention good pictures achieved xverden. The printing plate is installed in a printing machine (Multilith 1250) and used for printing use. Even with the twenty thousandth sheet, the same print quality is achieved as at the beginning.

Examples 15 and 14

An aluminum plate is roughened according to Example 1 and subjected to anodic oxidation. The dependence of the removed anodic oxide layer amount on the aluminum ion concentration in the treatment solution for the anodic oxide layer is investigated. The amount of anodic oxide layer removed is determined at an aluminum ion concentration of 0%, 0.5% and 0.6. The other conditions are given in Table 6. The aluminum ion concentrations are increased by adding Al (OH) ₇ . adjusted to the treatment solution.

Table 6

Example treatment
conditions Temp. Treat
lung
time V
ν see) Aluminum ions
concentration (%) 0.5 0.6 Treatment
solution 25th
40
70 10
^ 5
20th 0
(At first) (1.0)
(0.8)
(0.58) (9.9)
(o, 7)
(0.15) 15 sodium aluminate
(25% NaOH; 7%
Al)
14 sodium tri-
pho sphat
15 5% phosphorus
acid M)
Ci, o)
M)

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The numbers in brackets indicate the amount of anodic oxide layer removed (g / m).

Even with an increase in the aluminum ion concentration, no decrease in the amount of the anodic oxide layer removed by the aqueous sodium aluminate solution can be observed. In contrast, with a phosphoric acid solution containing 0.6% aluminum, only 15 % of the layer amount is removed that is achieved in the absence of aluminum ions. The amount removed by the aqueous sodium triphosphate solution drops to about 70 % at an aluminum ion concentration of 0.6%, but this result is far better than that for phosphoric acid. The aluminum plate obtained is then coated with a photosensitive mixture according to Example 9 and developed. In the case of the plates treated with sodium aluminate or sodium triphosphate solution, the image areas adhere firmly to the support even with vigorous rubbing, while they are firmly adhered to the support treated with a phosphoric acid solution containing 0.3 and 0.6% aluminum ions, respectively, by vigorous rubbing of development.

Examples 15-17

An aluminum2S plate roughened with a brush using the method of JA-OS 33 4-11 / 1973 is immersed in a 10% aqueous sodium hydroxide solution at 55 C for 20 seconds and then rinsed. A gray aluminum surface is created. The aluminum plate is then immersed in 70% nitric acid at room temperature for 60 seconds and then rinsed. A light aluminum surface is created. With the aluminum plate obtained as the anode and lead as the cathode, electrolysis is then carried out for 3 minutes in 20% strength sulfuric acid at 30 ^° C. with a direct current density of 2 A / dm. An oxide layer forms on the roughened surface

(3 »0 g / a). The aluminum plate thus obtained is then in

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Sulfuric acid, chromic acid or oxalic acid immersed. To the For comparison, the treatment is carried out with phosphoric acid. The treatment conditions are summarized in Table 7.

Table 7

Example treatment
conditions Temp.
C ⁸ G) Conc
trio
(Weight η
%: removed amount of
anodic ^ oxide layer
(g / m ² ) 1.0 1.5 2.0 Treatment
solution 65 5 0.5 (186) (234) (360) 15 sulfuric acid 65 5 (76) (248) (344) (416) 16 chromic acid 65. 5 (132) (186) (266) (328) 17 oxalic acid (106) Comparison
example 60 5 (45) (70) (92) 4 phosphoric acid (24) 33.3% 50.0% 66.0% percent removed
set of anodic
Oxide layer 16.7%

The numbers in brackets indicate the treatment time (see).

On those treated with sulfuric acid, chromic acid or oxalic acid Aluminum plates and the aluminum plate treated with phosphoric acid becomes the photosensitive mixture of Example 1 applied and dried for 2 minutes at 100 ° C. the

Coating amount is 2.5 g / m

The planographic printing plates obtained are then exposed through an original positive for 40 seconds at a distance of 70 cm using a 30 A arc lamp. The exposed plates are for 20 seconds at 30 ⁰ C in a 3% aqueous sodium

509844/1021

dipped in silicate solution and developed in this way.

The planographic printing plates obtained, from which 16.7% of the anodic oxide layer has been removed, are installed together in a printing machine (Multilith 1250) and used for printing. In the areas not treated with the acids mentioned, 5 % of the halftone dots disappear from the thirty thousandth sheet, while in the case of the substrates treated according to the invention with sulfuric acid or oxalic acid, even with the eighty thousandth sheet, the same print quality is achieved as at the beginning. The same results are achieved with supports from which the anodic oxide layer has been removed to 33.3 ° / 50% or 66 %. The supports treated according to the invention are superior to the supports treated with phosphoric acid in a known manner in terms of lightness, so that the image areas after development stand out clearly from the non-image areas. Furthermore, treatment with the cheap dibasic acids such as chromic acid, oxalic acid and sulfuric acid improves the properties of the anodic oxide layer on the aluminum surface, so that the aluminum plate can be used as a support for planographic printing.

Examples 18 and 19

An aluminum plate roughened and anodically oxidized according to Example 1 is in hydrofluoric acid or fluorozirconic acid submerged. For comparison, an aluminum plate is immersed in phosphoric acid. The treatment conditions and the ablated Amounts of the anodic oxide layer are shown in Table 8. The numbers in brackets indicate the processing time (see).

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Table 8

Treatment
conditions
example removed amount of
anodic oxide layer
(g / m ² ) Temp.
( ⁰ C) Conc
tration
(Wt%) > 0.5 1.0 1.5 2.0 Treatment
solution 15th
20th 2
5 (2.6)
(17.4) (3.2)
(35.0) (8.2)
(52.6) (11.0)
(72) 18 hydrogen fluoride
acid
19 fluorozirconic acid Comparison
example 60
25th 5
5 (23) (45) (65) (92) 5 phosphoric acid
6 phosphoric acid 5 min

The results show that with hydrofluoric acid and Fluorozirconic acid far faster treatment rates can be achieved than with phosphoric acid, although the treatment temperature and concentration are lower than in the case of use of phosphoric acid.

Those treated with hydrofluoric acid and fluorozirconic acid, respectively Aluminum plates are coated with the photosensitive mixture from Example 1, then according to Example 1 exposed and finally developed. Printing plates of great durability are obtained.

Examples 20 to 25

A 3S aluminum plate roughened according to Example 1 is immersed in a 20% aqueous sodium triphosphate solution for 60 seconds at 70 ° C dipped and then rinsed. The aluminum plate is then immersed for 1 minute at room temperature

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70% nitric acid and then rinses it. A light aluminum surface is created. With the aluminum plate obtained as the anode and lead as the cathode, electrolysis is carried out in 20% strength sulfuric acid at 30 ^° C. for 3 minutes

ρ '

carried out with a direct current density of 2 A / dm. It

an anodic oxide layer is created (3.2 g / m). The received About half of the aluminum plate is immersed in the following treatment solutions under the conditions shown in Table 9;

Table 9

Treatment - Temp. more worn Proζent 33% 50% 66.7% Example conditions ( ⁰ C) set of anodic
Oxide layer handling 65 (166) (234) (580) solution 65 17% (196) (256) (298) 20th (34.0) (52.6) (72) 20 5% sulfuric acid 65 (76) (248) (344) (416) 21 5% oxalic acid 65 (96) (180) (240) (360) 22 5% fluorozirconic acid (17 ^) 23 5% chromic acid 15th (132) (5.2) (8.2) (11.0) 24 3% nitric acid (92) 25 2% hydrogen fluoride acid (2.6)

"The numbers in brackets mean the treatment time (see).

Each of the aluminum plates is then photosensitive using a slinger with the following Mixture coated and then dried for 2 minutes at 100 ° C

net. The amount of coating is 1.5 g / m 2.

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lot

Polyvinylpyrrolidone ("K-90", the General

Aniline & Film Corporation) 4.5

Hydroxypropylmethyl cellulose ("Methose

60 SH "from SMnetsu Kagaku Kogyo Co., Ltd.) 0.25

Sodium 4,4'-diazido stilbene-2,2'-disulfonate 0.25

Crystal Violet (C.I .. 42 555) 0.05

Cyclohexane 5> 0

Ή , N-dimethylformamide 20.0

The photosensitive printing plate obtained then becomes 15th Seconds using a 30 Α arc lamp at a distance 70 cm exposed through an original positive. After this The printing plate is rinsed with water at tree temperature by firmly rubbing the coating layer with one with water soaked cotton cloth. In the areas treated according to Table 9, the image adheres well and withstands the development treatment stood, while there was no residue of the photosensitive mixture in the unexposed areas remains behind. On the other hand, in the untreated areas, the coating film is already peeling on the image areas when rubbing gently with the water-soaked cotton cloth.

An absorbent cotton cloth * ri.rd with a varnish for soaked the lithographic print ("Lack S" from Hansegen Co.). The varnish is then applied to the one developed above Open the plate by rubbing it with the cotton cloth. Then a printing ink ("RC 42-100, from Kalle AG) is applied to the paint layer. The so received

509844/1021

tene aluminum plate is then immersed for 2 minutes in an aqueous solution of 25.5 ° / ° phosphoric acid and 0.5% sulfuric acid at room temperature and then treated with a brush. The photosensitive layer obtained on the basis of the development described above and the lacquer and ink layers applied to it are removed here, while the lacquer layer applied directly to the aluminum plate and the ink layer applied to it remain as image areas. The printing plate produced in this way is installed in a printing machine (Multilith 1250) and used for printing. Even after the forty thousandth sheet, the same print quality is achieved as at the beginning.

Examples 26 to 31

An aluminum 2S plate roughened according to Example 1 is immersed in 10% aqueous sodium hydroxide solution at 40 ° C for 30 seconds dipped and then rinsed to obtain a gray aluminum surface. Then the aluminum plate is immersed 60 seconds at room temperature in 70% nitric acid, whereby a light aluminum surface is created. With the aluminum plate obtained as the anode and a stainless steel cathode Electrolysis is carried out for 3 minutes in 20% sulfuric acid carried out at 30 ° C with a direct current density of 2.5 A / dm. An oxide layer is created on the aluminum plate, (3.5 g / m) - The aluminum plate obtained becomes about half of those in Tables 10 and 11 Conditions immersed in the following treatment solutions. The numbers in brackets mean the treatment time (see).

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- 32 Table 10

Treatment
Example solution Temp. removed percentage of
anodic oxide layer 28.6% 71.4% 85.7% 26 5% chromic acid 65 14.3% (246) (430) (720) (132)

Table 11

Treatment
Example solution Temp.
( ⁰ C) removed percentage of
anodic oxide layer 33% (270) 66.7% 65 17% (180) (382) (360) 27 5% sulfuric acid 65 (84) (248) (62.4) (506) 28 5% oxalic acid 20th (122) (40.2) (322) (82.2) 29 5% fluorozirconic acid 65 (18.0) (206) (9.4) (486) 30 3% nitric acid 15th (102) (6.2) (13.0) 31 2% hydrogen fluoride
acid (3.0)

Each of the aluminum plates obtained is then immersed in an aqueous sodium silicate solution of the following composition at 65 ° C. for 20 seconds immersed and finally rinsed:

lot

40% aqueous sodium silicate solution
water

250 4000

50984 4/1021

Each of the plates is then coated with the aid of a centrifugal disk at room temperature at 100 ml / m 2 of the following greasing agent:

Polyvinylpyrrolidone ("K-90", the General

Aniline & GiIm Corp.) x 0.5 g

Methanol 1000 ml

The primer layer is then applied with the help of a centrifugal disk the following photosensitive mixture applied and dried for 2 minutes at 100 ° C:

lot

Condensate from 1, ^ - di-ß-hydroxyethoxycyclohexane and p-phenylenediacrylic acid (average molecular weight: 8000) 10.0

5-nitroacenaphthene 1.0

Dibutyl phthalate. 4.0

Phthalocyanine Blue 2.0

Monochlorobenzene ■ - 300

The amount of coating is now 1.7 g / m 2. The received open planographic printing plate is then used for 30 seconds Using a 30 Α arc lamp, exposed through an original negative at a distance of 70 cm and then rubbed with it an absorbent cotton cloth that can be used with is soaked in the following developer:

509844/1021

Amount (κ.)

4- butyrolactone 1000

Glycerin 100

Methyl abietate 10

hydrogenated tree resin ("Stabelite Resin")

Hercules Powder Co.) 1

Wetting agent ("Zonyl" from DuPont) 10.2

distilled water 100

85% phosphoric acid 25

In the surface areas not treated with the acids mentioned the Bimbezirke are already removed during development by lightly rubbing with the cotton cloth. In contrast, the image areas on the surface treated according to the invention can be removed even by vigorous rubbing do not remove while developing.

Each of the printing plates is then installed in a printing machine (Multi-Iith 1250) and used for printing. With all carriers, with the exception of the carrier in which 85.7 % of the anodic oxide layer has been removed, the same print quality is achieved with the eight thousandth sheet as at the beginning.

In the case of the printing plate carrier, its anodic oxide layer too 85 * 7% has been worn away on the whole Observe the scratches on the surface while pressing. This means that the anodic oxide layer is

509844/1021

preferably not more than about 70% are removed target.

Examples 32 and 33

With an aluminum plate roughened according to Example 1 as the anode and lead as the cathode, electrolysis is carried out for 4 minutes in an aqueous solution of 0.25 mol / l oxalic acid and 0.25 mol / l potassium oxalate at 54 ^° C. with a direct current density of 2 A / dm carried out. This creates an anodic oxide layer (3.2 g / m). Half of the obtained aluminum plate is then immersed in nitric acid or oxalic acid. The treatment conditions are summarized in Table 12. The numbers in brackets indicate the treatment time (see).

Table 12

Example treatment
iieispiei _solution Temp.
( ⁰ C) removed percentage of
anodic oxide layer 33% 50% 67% 32 3% nitric acid
33 5% oxalic acid 65
65 13% (208)
(200) (354)
(300) (460)
(400) (104)
(100)

The aluminum plate is then made according to Example 26 with sodium silicate treated with a primer and a photosensitive mixture coated, exposed and finally developed. In those not subjected to immersion treatment The image areas can be identified by lightly rubbing the aluminum support with an absorbent Remove the cotton cloth soaked in the developer.

509844/1021

In contrast, the image areas in the areas treated in the above manner adhere firmly to the aluminum surface.

The printing plate obtained in this way is installed in a printing machine (Multilith 1250) and used for printing. Even after the forty thousandth sheet, the same print quality is achieved as at the beginning.

Examples 34 and 55

The aluminum plates produced in Examples 32 and 33 are according to Example 20 with a photosensitive Mixture coated, dried, exposed and finally developed. In those not subjected to immersion treatment In areas, the image areas are removed during development, while they are in the areas treated according to the invention even when rubbing vigorously with a water-soaked one Adhere the cotton cloth firmly.

Examples 36 to 58

With an aluminum 2S plate roughened according to Example 1 as the anode and lead as the cathode, electrolysis is carried out for 10 minutes in a 3% aqueous chromic acid solution at 38 ° C. with a direct current density of 1 A / dm. The result is an anodic oxide layer (3 »5 g / ^m ) - about half of the aluminum plate obtained is treated with an acid under the conditions specified in Table 13 and then treated with sodium silicate according to Example 26, coated with a primer and a light-sensitive mixture, exposed and finally developed.

509844/1021

Table 13

Treatment solution Temp,
cm removed percentage of
anodic oxide layer 27% 46% 67.5% 2% hydrogen fluoride
acid
5% chromic acid
5% sulfuric acid 15th
60
65 13% (25)
(34-0)
(500) (50)
(562)
(850) (74)
(850)
(1250) (15)
(170)
(250)

The numbers in brackets indicate the diving times (see).

In the areas not subjected to the immersion treatment, the areas of the image are only removed by vigorous rubbing during the development, while good images are obtained in the areas treated according to the invention. The aluminum plates are in a printing machine (Multilith 1250) built in and used for printing. Even after the twenty thousandth sheet, the same print quality is achieved as at the beginning.

' Examples 39 and 40

A smooth aluminum 3S plate is placed in dipped into a 20% aqueous sodium triphosphate solution and then rinsed. The aluminum plate is then immersed in 70% nitric acid at room temperature and rinsed then. The aluminum surface treated in this way is free of oil and dirt. With the obtained aluminum plate as an anode and lead as cathode, electrolysis is carried out for 7 minutes in a 20% phosphoric acid solution at 35 ° ^ with a direct current

509844/1021

density of 2 A / dm. An anodic oxide layer is created (2.9 g / m ² ). About half of the plate obtained is then treated with an acid under the conditions given in Table 14. Then treated to the aluminum plate according to Example 26 with sodium silicate, it is coated with a primer and a light-sensitive mixture, and drying the coating obtained 30 minutes at 110 ⁰ C. The photosensitive J obtained? Laughing printing plate is then exposed according to Example 26 and entxo.ekelt. The image areas adhere firmly to the entire plate, but the development speed in the areas not subjected to the immersion treatment mentioned is only slow and coating residues remain in the unexposed areas. In the case of the acid immersion treatment, a larger amount of the oxide layer is removed, while at the same time the development speed is higher and fewer coating residues remain.

Table 14

Treatment solution Temp.
⁰ C) Percentage removed
the anodic oxide layer 27% 50% 65% 2% hydrofluoric acid
3% fluorozirconic acid 15th
20th 13% (6.6)
(30.4) (13.6)
(61.4) (17.4)
(49.0) (13.2)
(14.2)

The numbers in brackets mean the treatment time (see).

509844/1021

Between hydrofluoric acid and fluorozirconic acid there is no difference in the speed of development and the formation of coating residues.

Examples 41 and 42

As in Examples 18 and 19, aluminum plates are roughened and then roughened with hydrofluoric acid, fluorozirconic acid or phosphoric acid treated. The aluminum plates whose

anodic oxide layer of 0.5, 1.0 or 1.5 g / ^m 2 has been removed again, are then coated with the following photosensitive mixture:

lot

Polyvinylpyrrolidone ("K-90", the

General Aniline & Film Corp.) 4.5

Hydroxypropyl methylcellulose

Shinetsu's "Metolose 60 SH 4000"

Kagaku Eogyo Co.) 0.25

Sodium 4,4'diazidostilbene-2,2'-di-

sulfonate 0.25

Crystal Violet (CI. 42 555) 0.05

Methyl glycol 16

■ ethylene chloride 8

The amount of coating is 1.5 g / m, based on the Dry weight.

The resulting photosensitive printing plates are then placed at a distance of 15 seconds using a 30 A arc lamp 70 cm exposed through a positive. After rinsing

50984 kl 10 21

the plates are thoroughly cleaned with water at room temperature Rubbing developed with a cotton cloth soaked in water. This is done with the help of an absorbent Cotton fabric is a commercially available lithography and I-printing varnish ("Lack S" from Hansgen Co ») applied. The paint layer is finally coated with a printing ink ("EC 42-100" from Kalle AG) using a sponge. The plate is then immersed for 2 minutes in an aqueous solution of 2.55% phosphoric acid and 0.5% sulfuric acid and removes the varnish and coloring layers in the image areas with the help of a brush.

The printing plates produced in this way are installed in a printing machine (Harrisaurelia 125) and used for printing. If you reduce the amount of water added while pressing, the unexposed ones will also smear Areas of the plate treated with phosphoric acid, while this was not observed in the case of the plate treated according to the invention is. In the case of the printing plate supports produced according to the invention, printing ink and wetting liquid can thus be used Apply (water) lightly in a balanced ratio.

509844/1021

Claims (5)

Claims \ 1 »Process for the production of printing plate supports made of aluminum, characterized in that
that an anodic oxide layer is produced on the surface of a plate made of aluminum or an aluminum alloy and this is treated either with a basic solution or with a solution containing at least one monobasic and / or dibasic acid, so that about 5 to 70 percent by weight of the oxide layer is removed again will. 2. The method according to claim 1, characterized in that the treated plate is optionally subjected to a further surface treatment to improve the hydrophilic properties. 3 · The method according to claim 1, characterized in that g e k e η η ζ eichnet that the anodic oxide layer at an electrolyte concentration of about 1 to 80 percent by weight, onex * bath temperature of about 5 "to 70 ° C, one ο
Generates current density of about 0.5 to 60 A / dm, a voltage of about 1 to 100 volts and an electrolysis time of about 30 seconds to 50 minutes. 4. Vex * drive according to claim 1, characterized g e k e η η ζ ei c h η e t that the treatment of the anodic oxide layer with an approximately 0.1 to 80 percent by weight basic solution for about 1 second to 10 minutes at a temperature of about 5 "to 95 ° C. 5. The method according to claim 1, characterized in that the treatment of the anodic 509844/1021 - Oxide layer with an approximately 0.5 to 100 percent by weight Acid solution for about 1 second to 10 minutes at a temperature of about 10 to 95 ° G. 509844/1021