JPH0692195B2 - Treated anodized aluminum support and lithographic printing plate containing same - Google Patents

Description

Description: FIELD OF THE INVENTION This invention relates to support materials used in lithographic (lithographic) printing plates and has improved press sensitivity.
And a lithographic printing plate made of a support material exhibiting an extended shelf life.

[Prior art]

One important feature of any presensitized lithographic printing plate is its ability to stably retain and exert reproducible photographic speed performance during its manufacture and its subsequent use. Yet another important property is the ability of the printing plate to repel ink from non-image areas initially and throughout the useful life of the printing plate.

U.S. Pat. No. 4,492,616 describes a method of treating an aluminum oxide layer by treating the metal surface with an aqueous alkali metal silicate solution and an aqueous solution containing alkaline earth metal ions.

U.S. Pat.No. 3,860,426 describes a lithographic printing plate having a hydrophilic cellulose subbing layer containing a water soluble salt of a metal to reduce plate scumming in areas where the printing layer is removed. There is. Although these printing plates are widely commercially accepted, they must exhibit reproducibility of speed performance between when the printing plate was manufactured and when it was used under all storage and handling conditions encountered. Has not been found. In addition, the printing industry has demanded more pressing requirements for pressure sensitivity in an effort to minimize change and wear.

Thus, lithographic printing plates need to exhibit improved pressure sensitivity and extended shelf life.

[Structure of Invention]

The present invention comprises an anodized aluminum plate having an anode layer, a silicate layer in contact with the anode layer and a metal salt layer in contact with the silicate layer, wherein the metal salt layer comprises:
A metal having the formula MX, where M is a metal selected from the group consisting of zinc, magnesium, nickel and chromium, and X is an anion selected from the group consisting of acetates, chlorides and borates. A lithographic printing plate support material comprising a salt is provided.

The lithographic printing plate according to the present invention comprises a) an anodized aluminum plate having an anode layer, a silicate layer in contact with the anode layer and a metal salt layer in contact with the silicate layer, wherein the metal salt layer is of the formula MX (wherein M Is a metal selected from the group consisting of zinc, magnesium, nickel and chromium,
X is a riffgraphic printing plate support material consisting of a metal salt having an anion selected from the group consisting of acetates, chlorides and borates and b) a radiation sensitive layer. The lithographic printing plate of the present invention exhibits improved pressure sensitivity and extended shelf life.

The support material consists of aluminum or aluminum alloy plates. Suitable aluminum alloys are alloys with zinc, silicon, chromium, copper, manganese, magnesium, lead, bismuth, nickel, iron or titanium, which alloys may contain negligible amounts of impurities.

The surface of the aluminum plate is preferably chemically cleaned such as degreasing with a solvent or an alkaline agent in order to expose a clean surface free from oils, rusts and dusts that are usually present on the aluminum surface. Preferably the surface is polished.
Suitable polishing methods include glass bead polishing, ball polishing, sandblasting, brush polishing and electrolytic polishing.
Following the polishing operation, the support can be treated with an aluminum etchant and a desmutting acid bath.

Then an anodized layer is formed on the aluminum plate. This layer is referred to herein as the anode layer.
An electric current is applied to a support immersed as a cathode in a solution containing one or more acids selected from phosphoric acid, sulfuric acid, oxalic acid, boric acid, chromic acid, sulfamic acid and benzenesulfonic acid. Thus, the anodized layer is formed on the surface of the support.

After anodization, the surface of the anodized aluminum plate is contacted with a silicate agent such as an alkali metal silicate, calcium silicate, silicic acid, colloidal silica or polymeric silicic acid to silicate the plate. The silicate treatment makes the anodized surface hydrophilic. Preferably,
The support is treated with an aqueous solution of silicate agent. The silicate agent is preferably present in a concentration of about 0.5% to about 10% and the temperature of the solution is 20 ° C to 100 ° C, most preferably 60 ° C to 1%.
It is 00 ° C. The optimal immersion time of the plate in the solution is the solution temperature,
Depends on silicate agent concentration and end use of the lithographic version. A dipping time of 15-80 seconds has been found to be particularly advantageous.

After silicate making the plate, the silicate plate is made into the formula MX
Wherein M is a metal selected from the group consisting of zinc, magnesium, nickel and chromium, and X is an anion selected from the group consisting of acetate, chloride and borate. Contact. Thus, perhaps often a substantially monolayer thin treatment or layer of metal salt is provided. In some cases, metal salt molecules appear to be unevenly deposited on the surface. This layer is 10-50
mg / m ^2, preferably present at a coverage of 20-40 mg / m ^2. Metal salts that are particularly useful include water-soluble salts of zinc, magnesium, nickel and chromium. These salts are formed by methods known in the art. Useful salts include
Includes acetates, chlorides and borates. The support is immersed in a water bath containing the metal salt, preferably at a concentration of 0.1% to 45%. Higher concentrations are limited only by the solubility of the metal salt. The preferred metal salt bath concentration is 1% to 10%, most preferably 2% to 5%. The metal salt layer may consist essentially of the metal salts described above. The bath can be operated from room temperature to the boiling point, but temperatures of 32 ° C to 82 ° C are preferred. Excellent results are achieved with bath temperatures of 49 ° C to 71 ° C. The immersion time of the plate in the bath depends on the concentration and the temperature. It has been found that soaking times of 10 seconds to 5 minutes are acceptable under many conditions. Preferably, the immersion time is between 15 seconds and 3 minutes, thus the treatment can be a continuous process.

The lithographic printing plate support material of the present invention, if desired,
It may be coated with a thin coating of hydrophilic material which acts as a subbing layer. The hydrophilic coating serves to improve the water receptivity of the non-printed areas of the treated plate. Preferably, the hydrophilic coating is coated on the support treated as described above. The hydrophilic coating is coated in a subbing amount by a known technique. In particular, it is advantageous to use water-soluble permanently hydrophilic substances which can be coated from aqueous dispersions. Solutions containing polyacrylamide are particularly advantageous for this purpose, as are solutions containing carboxymethylcellulose, polyvinylphosphonic acid, sodium silicate and combinations thereof. Other polymers useful in forming the hydrophilic intermediate layer include polyvinyl alcohol, copolymers of maleic anhydride and ethylene, vinyl acetate,
Includes styrene or vinyl methyl ether, polyacrylic acid, hydroxymethyl cellulose and polyvinylpyrrolidone.

The lithographic printing plate according to the invention comprises a) an anodized aluminum plate having an anode layer, a silicate layer in contact with the anode layer and a metal salt layer in contact with the silicate layer,
The metal salt layer is of the formula MX (wherein M is a metal selected from the group consisting of zinc, magnesium, nickel and chromium, and X is an anion selected from the group consisting of acetate, chloride and borate). A) a lithographic printing plate support material consisting of a metal salt having a) and b) a radiation sensitive layer.
After the metal salt coating has dried, the radiation-sensitive coating is placed on its surface. The radiation-sensitive coating is placed directly on the lithographic printing plate support material or preferably on one or more subbing layers. A wide variety of radiation-sensitive materials suitable for forming images for use in lithographic printing processes can be used. Almost all radiation-sensitive layers are suitable and, after exposure, if necessary, then developed and / or
Or fused to provide an imagewise distribution area that can be used for printing.

Radiation sensitizers useful in the present invention are well known in the art and are described in Research Disclosure, publication 17643, parag.
silver halide as described in raph XXV, Dec., 1978 and references therein; US Pat. No. 4,141,73.
No. 3 (issued February 27, 1979 to Guild) and quinonediazides (polymerizable and non-polymerizable) as described in the references therein; US Pat. No. 3,511,611 (May 1970)
Issued to Rauner et al. 2) and a photosensitive polycarbonate as described in the references therein; US Pat.
342,601 (issued on September 19, 1967 to Houle et al.) And the diazonium salts, diazo resins, cinnamalumaronates and their functional equivalents and others described therein and U.S. Pat. No. 4,139,390. (Issued February 13, 1979 to Rauner et al.) And the references therein and the photosensitive polyesters, polycarbonates and polysulfonates.

Particularly useful radiation sensitive materials are polymer backbones.
a photosensitive group as an essential part of e) Are photo-crosslinkable polymers such as polyesters containing. For example, a preferred photocrosslinkable polymer is a polyester prepared from one or more compounds represented by the formula:

(In the formula, R ² is one or more kinds, alkyl having 1 to 6 carbon atoms, aryl having 6 to 12 carbon atoms, aralkyl having 7 to 20 carbon atoms, and having 1 to 6 carbons. An atom of alkoxy, nitro, amino, acryl, carboxyl, hydrogen or halogen, selected to provide at least one condensation position, R ³ is hydroxy, alkoxy of 1 to 6 carbon atoms, halogen or a compound. Is oxy when it is an acid anhydride.) A preferred compound is p-phenylenediacrylic acid or its functional equivalent. These and other useful compounds are described in US Pat. No. 3,030,208 (1962
Issued to Schellenberg et al. On Apr. 17, 2014; US Pat. No. 3,702,
765 (issued November 14, 1972 to Laakso); and U.S. Pat. No. 3,622,320 (issued November 23, 1971 Allen).

Wherein R ³ is as defined above and R ⁴ is alkylidene of 1 to 4 carbon atoms, aralkylidene of 7 to 16 carbon atoms or 5- to 6-membered heterocycle. Particularly useful compounds of (B) are cinnamylidene malonic acid, 2-butenylidene malonic acid, 3-pentenylidene malonic acid, 0
-Nitrocin namylidene malonic acid, naphthyl allylidene malonic acid, 2-furfurylidene ethylidene malonic acid and their functional equivalents. These and other useful compounds are described in US Pat. No. 3,674,745 (Phili, July 4, 1972).
Published in pot et al.).

(Wherein R ³ is as defined above and R ⁵ is hydrogen or methyl.) Particularly useful compounds of formula (C) are trans, trans-muconic acid, cis, trans-muconic acid,
Cis, cis-muconic acid, α, α'-cis, trans-dimethylmuconic acid, α, α'-cis, cis-dimethylmuconic acid and functional equivalents thereof. These and other useful compounds are described in US Pat. No. 3,615,434 (October 2, 1971).
Issued on 6th McConkey)).

(Wherein R ³ is as defined above and Z represents the atom necessary to form an unsaturated bridged or unbridged carbocyclic nucleus of 6 to 7 carbon atoms.) The nucleus may be substituted or unsubstituted. Particularly useful compounds of formula (D) are 4-cyclohexene-1,2-dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid, hexachloro-5 [2: 2: 1] -bicycloheptene-2,3- Dicarboxylic acids and their functional equivalents. These and other useful compounds are described in Canadian Patent 824,096 (September 1969).
Issued on March 30th to Mench et al.).

(In the formula, R ³ is as defined above, R ⁶ is hydrogen, 1 to 12
Is alkyl of 6 carbon atoms, cycloalkyl of 5 to 12 carbon atoms or aryl of 6 to 12 carbon atoms. ) R ⁶ may be optionally substituted with substituents such as halogen, nitro, aryl, alkoxy, aryloxy, etc., which do not interfere with the condensation reaction. The carbonyl groups are attached to the cyclohexadiene nucleus in the meta or para position, preferably the para position. Particularly useful compounds of formula (E) are 1,3-cyclohexadiene-1,4-dicarboxylic acid, 1,3-cyclohexadiene-1,3-dicarboxylic acid, 1,5-cyclohexadiene-1, 4-dicarboxylic acid and functional equivalents thereof. These and other useful compounds are described in Belgian Patent No. 754,892 (October 1, 1970).
Issued on the 5th).

Radiation-sensitive coatings can be prepared by dispersing the radiation-sensitive composition or polymer in any suitable solvent or combination of solvents used in the art.

Radiation sensitivity can be stimulated by including a sensitizer therein in the coating composition. Suitable sensitizers include 1-carbentoxy-2-keto-3-methyl-
Anthurons such as 2-azabenzanthrone and benzanthrone; nitro sensitizers; triphenylmethane; quinones; cyanine dye sensitizers; naphthone sensitizers such as 6-methoxybeta-2-freel-2-acrylonaphthone; 2,6
-Pyrylium or thiapyrylium such as -bis (p-ethoxy-phenyl) -4- (pn-amyloxyphenyl) -thiapyrylium perchlorate and 1,3,5-triphenylpyrylium fluoroborate; furanone; 4-
Picoline-N-oxide; anthraquinones such as 2-chloroanthraquinone; 2-benzoylcarbetoxymethylene-1-methyl-beta naphthothiazole and methyl 2
Thiazoles such as-(n-methylbenzothiazolilidene) dithioacetate; methyl 3-methyl-2-benzothiazolidene dithioacetate; 3-ethyl-2-benzoylmethylene-naphtho [1,2-d] -thiazoline, Thiazolines such as benzothiazoline, (2-benzoylmethylene) -1-methyl-beta-naphthothiazoline; 1,2-
Dihydro-1-ethyl-2-phenacylidenenaphtho [1,
2-d] -thiazole; and naphthothiazoline; quinolizone, Michler's ketone; and Michler's thioketone.

In addition to the sensitizer, numerous other additives may be present in the coating composition, ultimately forming part of the lithographic plate. For example, dyes or pigments may be included to provide a colored image to aid recognition. Other components which may be advantageously included in the coating composition are materials which are intended to improve film formation, coatability, adhesion of the coating to the support, mechanical strength and stability.

The lithographic printing plates of the present invention can be exposed to the imagewise pattern of actinic radiation by conventional methods, for example through transparencies or stencils. Suitable radiation sources include carbon arc lamps, mercury vapor lamps, fluorescent lamps, tungsten filament lamps, photographic lamps, lasers and the like.

The exposed lithographic printing plate can be developed using conventional developers and developing techniques. For example, when developing a lithographic printing plate containing the above radiation-sensitive polyester,
The developer composition is applied to the surface of the plate for a time sufficient to remove the polymer from the non-image areas of the plate. The slow mechanical action helps remove the polymer composition from these areas.
Thus, wiping is a useful method of applying the developer composition to the board. The developer composition is typically used at room temperature, but can be used at elevated temperatures up to about 32 ° C.
A second application can be applied after the first application of the developer composition, followed by one or two applications of the desensitizing composition. The plate is then dried.

〔Example〕

The present invention will be further described in the following examples, but it goes without saying that the scope of the present invention is not limited to these examples.

Example 1 and Comparative Examples AB Aluminum plates were immersed in a caustic solution to remove oil and stains from the surface. The surface was polished with a brush and a slurry of abrasive. The loose residue was removed by etching in caustic solution followed by a nitric acid desmutting bath. The aluminum plate was anodized in phosphoric acid electrolyte.

The board of Comparative Example A was coated with a thin layer of polyacrylamide at a coverage of 14 mg / m ² . The plate is U.S. Pat.No. 3,030,208,
It was coated with a radiation-sensitive coating as described in Hydroxyethoxycyclohexane and p-phenylene diethoxy acrylate condensate.

The plate of Comparative Example B was prepared and anodized as described above.
The anodized support was treated in a 2% solution of PQ-D sodium silicate sold by PQ Corporation.
The SiO ₂ to Na ₂ O ratio was 2: 1. The support was immersed for 45 seconds in a bath having a temperature of 82 ° C. Wash the support, dry,
Coated with polyacrylamide and radiation sensitive layer as described above.

The plate of Example 1 was prepared and anodized as described above,
It was treated in a 2% solution of PQ-D sodium silicate in a 86 ° C. bath for 30 seconds. The plate was immersed in a water bath containing 2% zinc acetate for 30 seconds. The bath temperature was 65 ° C. The support was washed, dried and coated with polyacrylamide and radiation sensitive layer as described above.

Dried plate with 14 steps
film) containing a tablet) and exposed to a radiation source rich in UV light. The exposed plate was treated with a negative developer, a lithographic plate finish and dried. Developers and finishes are those described in Examples 1-8 of U.S. Pat. No. 4,419,437.

The pressure sensitivity and shelf life of the printing plate were measured as follows. The shelf life of the printing plate was determined by comparing the change in log E speed of the coated plate using a step tablet after incubation (incubation) at 49 ° C for 2 weeks with the speed of a new printing plate that was not incubated. It was determined by measuring. The pressure sensitivity test involves measuring the speed at which the printing plate repels or drops ink from the non-image areas and places the plate on a printing press. The press is started so that the plate receives the entire ink charge in both the image and non-image areas,
That is, no dampening system is applied. A mitigation system is then applied and the printing is made such that ink falls from the non-image areas. This operation is repeated 10 times with holding for 5 minutes. The results reported are calculated from the 11th hold for the last hour and are determined from background ink density measurements taken from the first 20 sheets. The results show the commercially available Kodak Polymatic ^TM Litho
Reported in comparison to Plates performance.

Comparative Example B shows a significant improvement in pressure sensitivity over the non-silicated version of Comparative Example A. However, the unexposed radiation-sensitive layer of Comparative Example B showed insolubilization of the layer due to reaction with the silicate present on the support, rendering the plate useless and unable to be removed by the developer.

Example 1 of the present invention shows that the printing plate subjected to the process of the present invention exhibits improved pressure sensitivity and excellent plate stability.

Examples 2-3 Effects of bath temperature Printing plates were prepared and tested as in Example 1 except that the temperature of the zinc acetate bath was as follows.

The results show that increasing bath temperature improves stability.

Examples 4 to 8 Effect of Bath Concentration The printing plate was immersed in a 49 ° C. bath for 25 seconds, and the concentration of the zinc acetate bath was changed as follows.
Plates were prepared and tested.

The results show that storage stability reaches a maximum at bath concentrations of about 2%.

Examples 9 to 16 Effects of bath components A printing plate was prepared and tested in the same manner as in Example 1 except that the following bath components were evaluated by the following concentrations, bath temperatures and plate immersion times.

The unexposed radiation-sensitive layers of Examples 10 and 11 could not be removed by the developer. The result is that zinc chloride requires a higher bath temperature than zinc acetate to exert stability,
It has been shown that zinc acetate is a preferable salt from the viewpoint of its excellent performance as a reagent for improving the stability of the plate.

Example 17 Effect of Radiation Sensitive Layer Except that the radiation sensitive composition was a positive-acting copolymer of alkyl acrylate, acryloyloxyalkyl quinone diazide acid ester and acryloyloxyalkyl carboxylate repeat units as described in U.S. Pat. A printing plate was prepared as described in Example 1. The silicated plate was contacted with a 3.0% zinc acetate bath at 60 ° C for 28 seconds. The printing plate of this example was properly exposed and processed using the appropriate lithographic developer and finish. An acceptable printing plate was provided in this way.

A printing plate prepared according to this example but not silicated was unacceptable. The silicate version prepared according to this example but not subjected to the zinc acetate treatment could not be used under some handling conditions.

Example 18 Effect of anodizing electrolyte An aluminum plate supplied by Anocoil Corporation was polished with a wire brush and anodized in sulfuric acid electrolyte. The diazo resin sold by Western as Western Wipe-on resin was coated on the anodized plate to a resin coverage of 75 mg / m ² . The solution was coated without water. Ol
An in 10G surfactant was used as a coating aid. The resulting printing plate was exposed to a metal halide light source through a step tablet having 14 steps. The exposed printing plate was treated with tap water. The printing plate was hand inked with rub-up ink to provide a visible image, washed and dried. This printing plate gained speed gain after incubation showing instability.

The aluminum plate anodized as described above was silicated as in Comparative Example B by immersion in a solution of sodium silicate. The plate was coated, exposed and processed as described above in this example. This printing plate could not be post-treated after incubation as the diazo resin coating showed very poor stability.

Anocoil as described above except that the silicate stage was followed by treatment in a zinc acetate solution as in Example 1.
An aluminum printing plate was prepared. The printing plate had very little speed gain after incubation, but was cleanly processed before and after incubation, indicating a very stable printing plate.

Effects It is an advantageous technical effect of the present invention that the lithographic printing plates comprising the metal salt layers described herein exhibit improved pressure sensitivity and extended shelf life.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-59-59897 (JP, A) JP-A-56-21126 (JP, A) JP-A-49-96803 (JP, A)

Claims (2)

[Claims] 1. An anodized aluminum plate having an anode layer,
A silicate layer in contact with the anode layer and a metal salt layer in contact with the silicate layer, wherein the metal salt is of the formula MX, wherein M is a metal selected from the group consisting of zinc, magnesium, nickel and chromium. And X is an anion selected from the group consisting of acetate, chloride and borate)
A lithographic printing plate support material comprising: 2. A support material comprising a radiation-sensitive layer, an anodized aluminum plate having an anode layer, a silicate layer in contact with the anode layer and a metal salt layer in contact with the silicate layer, the metal salt having the formula MX. Wherein M is a metal selected from the group consisting of zinc, magnesium, nickel and chromium, and X is an anion selected from the group consisting of acetate, chloride and borate. And lithographic printing version.