JPH0528198B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an aluminum alloy support that is used for lithographic printing after being subjected to anodizing treatment and coating with a photosensitive material.More specifically, the present invention relates to an aluminum alloy support that is used for planographic printing after being subjected to anodizing treatment and coating with a photosensitive material. The present invention relates to an aluminum alloy support and a method for producing the same, which provide a lithographic printing plate that has excellent stain resistance in non-image areas and does not exhibit streaks. (Prior Art) A lithographic printing plate is prepared by subjecting an aluminum alloy plate or the like as a lithographic printing plate support to surface treatments such as roughening treatment and anodic oxidation film treatment, and then applying a photosensitive substance thereto. This lithographic printing plate is then subjected to plate-making processes such as exposure and development to form a printing plate with image areas formed thereon, and after being wrapped around a cylindrical copper plate of a printing machine, dampening that has adhered to the non-image areas is removed. Lithographic printing is performed by depositing ink on the image in the presence of water, transferring the ink to a rubber blanket, and then printing onto paper. Conventionally, such aluminum alloy plates for lithographic printing plates are suitable for electrochemical roughening treatment, and are aluminum alloys containing 0.35 to 1% by weight of Fe (hereinafter, weight% is abbreviated as %) and 0.2% or less of Si. Aluminum alloy plate (Japanese Unexamined Patent Application Publication No. 1989-1989) which was homogenized, hot-rolled, and then cold-rolled by 40 to 80%.
28874), Fe 0.1~1.0%, Si 0.02~0.15%,
Aluminum alloy plate with Cu 0.003% or less
-221254), and others.
Aluminum alloy plates containing predetermined amounts of Fe and Si are disclosed in JP-A-58-42493 and JP-A-59-67349. (Problems to be Solved by the Invention) If the above-mentioned conventional aluminum alloy plate for lithographic printing plates is used, a uniformly roughened surface can be obtained by electrochemical roughening treatment. However, with these aluminum alloy plates, streaks (streak-like unevenness) occur during the surface roughening process, which significantly impairs the aesthetic appearance, or when printing a large number of copies (more than tens of thousands of copies), ink may adhere to non-image areas. However, it was not possible to overcome the problems of stains occurring on the printed matter. Among these, when hot rolling conditions are not appropriate, coarse recrystallized grains (~100 μm or more) are generated between hot rolling passes, and their outlines remain even after the final cold rolling, resulting in electrolytic surface roughening treatment. This is thought to be because fibrous streaks (streak-like unevenness) extending in the rolling direction appear at the time of rolling. In addition, the presence of certain intermetallic compounds causes the formation of unhealthy areas in the anodic oxide film, and the difference in potential between the aluminum matrix and the non-image area causes corrosion, which causes stains. be. Therefore, it is an object of the present invention to obtain a uniform, finely roughened surface by electrochemical surface roughening treatment, to prevent the occurrence of streaks (streak-like unevenness), and to prevent stains in non-image areas during printing. An object of the present invention is to provide an aluminum alloy plate for a lithographic printing plate in which almost no carbon is generated. (Means for Solving the Problems) As a result of intensive research to overcome the above-mentioned drawbacks of the conventional aluminum alloy plates, the inventors of the present invention have determined that the amounts of Fe, Si, and Cu in the aluminum alloy are within a predetermined range. The inventors have found that an aluminum alloy plate in which the amount of elemental Si in the metal structure is regulated to a certain amount or less can achieve the above object, and based on this knowledge, the present invention has been made. . That is, in the present invention, Fe 0.05 to 1%, Si 0.2%
Hereinafter, an aluminum alloy support for a lithographic printing plate, which is an Al alloy plate consisting of 0.05% or less of Cu, the balance Al and unavoidable impurities, and has 0.012% or less of elemental Si distributed in its metal structure. After soaking an aluminum alloy ingot consisting of Fe 0.05-1%, Si 0.2% or less, Cu 0.05% or less, and the balance Al and inevitable impurities, an average cooling rate of 50
℃/hour or less to a temperature of 430℃ or less, or
Or, hold at a temperature of 350 to 450℃ for 30 minutes or more, then hot-roll, or after hot-rolling, cold-roll and intermediate annealing, and then add final cold-rolling with an area reduction of 50% or more. This provides a method for producing an aluminum alloy support for a lithographic printing plate, characterized in that the amount of elemental Si distributed in the metal structure of a cold rolled plate is 0.012% or less. First, the alloy composition used in the present invention will be explained. In the alloy composition, Fe is in the range of 0.05 to 1%. Fe has the effect of making the electrolytically roughened surface uniform.
Fe combines with other elements in aluminum alloys,
It is an element that forms Al-Fe-based amorphous compounds,
Al-Fe-based amorphous compounds are effective in refining recrystallized grains and forming uniformly fine electrolytically rough surfaces. There is little uniform fine effect on the planarized surface,
Moreover, if the content exceeds 1%, the electrolytically roughened surface will become non-uniform due to the formation of coarse compounds. Si should be 0.2% or less. Si is included as a normal impurity, and if it exceeds 0.2%, the uniformity of the rough surface is impaired, and the precipitation of elemental Si, which will be described later, is likely to occur, resulting in staining of non-image areas. The reason for limiting Cu to 0.05% or less is that it is considered an impurity.
This is because if the Cu content exceeds 0.05%, pits formed by electrochemical surface roughening treatment tend to become coarse, and the stain resistance of non-image areas of the printing plate decreases. In addition, the amount of elemental Si distributed in the metal structure of the final cold-rolled sheet was limited to 0.012% or less because elemental Si remains in the anodized film due to anodizing treatment and forms film defects. This is because this becomes the starting point for stains in non-image areas during printing, and by regulating the amount of elemental Si to 0.012% or less, stains in non-image areas are less likely to occur, resulting in extremely excellent printability. It has been discovered that it can be made into a printed version. Impurities contained in the aluminum alloy constituting the lithographic printing plate support in the present invention include:
The object of the present invention will not be impaired if the impurities are at the same level as those contained in commercially available Al ingots.
That is, Mn 0.05% or less, Cr 0.05% or less, Zn 0.05%
If it is below, there is no particular problem. In addition, when manufacturing ingots, Ti and B, which are usually used as crystal refining agents, contain less than 0.05% Ti and B
Addition of 0.01% or less is effective in uniformly refining the alloy structure. As described above, in manufacturing the lithographic printing plate support of the present invention, an aluminum alloy ingot having the above composition is subjected to a soaking treatment to dissolve impurities and a part of Fe in solid solution. Intermediate compounds are uniformly and finely dispersed. This soaking process is 500
It is desirable to carry out the reaction at a temperature of ~620°C for 3 hours or more. This is then heated for 50 minutes until reaching a temperature below 430℃.
Cooling at an average cooling rate of less than or equal to °C/hour, or
By holding the ingot at a temperature of 350 to 450°C for 30 minutes or more, the Si atoms contained in the ingot are precipitated as Al-Fe-Si intermetallic compounds, thereby reducing the amount of elemental Si precipitated in subsequent steps. Furthermore, since this Al-Fe-Si intermetallic compound acts as a nucleus for recrystallization between hot rolling passes, it has the effect of refining recrystallized grains and is extremely effective in preventing the occurrence of streaks. Thereafter, hot rolling is carried out in a conventional manner, or cold rolling and intermediate annealing are performed after hot rolling. The hot rolling temperature is preferably 450 to 200°C. Hot rolling start temperature is 450℃
If it exceeds this, the recrystallized grains between hot rolling passes will become coarse, 100 μm or more, and streaks are likely to occur. Intermediate annealing after hot rolling, which is performed as necessary, is 350 ~
2 to 5 hours at 500℃ or in a continuous annealing furnace
It is desirable to carry out the heating at 400 to 550°C for 120 seconds or less. The plate thus obtained is finally cold rolled so that the reduction in area is 50% or more. In this final cooling rolling, intermetallic compounds are dispersed and the crystal structure becomes uniform. If the area reduction rate is less than 50%, the intermetallic compound will not be sufficiently dispersed and the crystal structure will be non-uniform, making it impossible to obtain a uniformly roughened surface in the surface roughening treatment. The cold-rolled plate thus obtained has an elemental Si content of 0.012% or less in its metal structure,
A uniformly roughened surface is obtained by electrolytic surface roughening treatment, and a lithographic printing plate with no streaks and extremely excellent stain resistance in non-image areas during printing is obtained. Note that, in order to impart appropriate ductility to this final cold-rolled sheet and improve its fatigue strength, temper annealing may be performed under the following conditions in which precipitation of elemental Si does not occur. Temperature annealing is suitably carried out at 70 to 180°C for 30 minutes or more in a normal batch furnace.
It is not very effective if it is below 70℃ or for less than 30 minutes.
At temperatures above 180°C, elemental Si will precipitate, impairing the stain resistance of non-image areas. Temperature annealing may be performed in a continuous annealing furnace characterized by rapid temperature rise and short heating time, and in this case, it is appropriate to heat at 150 to 400°C for 120 seconds or less. The effect is insufficient below 150℃, 400℃
If the temperature exceeds 120°C, the board will become too soft and the temperature will exceed 120°C.
If the heating time is longer than seconds, productivity will be poor. Next, a method for surface treating a lithographic printing plate support according to the present invention will be explained in detail. The graining methods used in the present invention include an electrochemical graining method in which graining is performed electrochemically in a hydrochloric acid or nitric acid electrolyte, a wire brush graining method in which the aluminum surface is scratched with a metal wire, and an aluminum surface using an abrasive ball and an abrasive agent. Mechanical graining methods such as the ball grain method, which grains the surface, and the brush grain method, which grains the surface using a nylon brush and abrasive, can be used, and any of the above graining methods can be used alone or in combination. You can also do it. Aluminum grained in this way is
Chemically etched with acid or alkali. When an acid is used as an etching agent, it takes time to destroy the fine structure and structure, which is disadvantageous in industrial application of the present invention, but this can be improved by using an alkali as an etching agent. The alkaline agent suitably used in the present invention includes caustic soda, soda carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide, etc., and the preferred ranges of concentration and temperature are 1 to 50% each. %, 20 to 100°C, and conditions such that the amount of Al dissolved is 5 to 20 g/m ² are preferable. After etching, pickling is performed to remove any dirt (smut) remaining on the surface. The acids used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and hydroborofluoric acid. In particular, for smut removal treatment after electrochemical surface roughening treatment, it is preferable to contact with 15 to 65% by weight sulfuric acid at a temperature of 50 to 90°C as described in JP-A-33-12739. and the alkali etching method described in Japanese Patent Publication No. 48-28123. The aluminum plate treated as described above can be used as a support for a lithographic printing plate, but it is preferable to further perform treatments such as anodization coating treatment and chemical conversion treatment as necessary. The anodic oxidation treatment can be performed by a method conventionally used in this field. Specifically, when a direct or alternating current is passed through aluminum in an aqueous or non-aqueous solution of sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, etc. or a combination of two or more of these, the aluminum support An anodic oxide film can be formed on the surface. The treatment conditions for anodic oxidation vary depending on the electrolyte used, so they cannot be determined unconditionally.
Generally, the concentration of electrolyte is 1~80%, and the temperature of the electrolyte is 5~70%.
°C, current density 0.5~60 ampere/ ^dm2 , voltage 1~
A range of 100V and electrolysis time of 10 to 100 seconds is appropriate. Among these anodic oxide film treatments, the method of anodizing at high current density in sulfuric acid used in the invention described in British Patent No. 1412768 and the method described in U.S. Patent No. 3511661 are particularly A method of anodizing using phosphoric acid as an electrolytic bath is preferred. The aluminum plate to be anodized may be further treated by dipping in an aqueous solution of an alkali metal silicate, such as sodium silicate, as described in U.S. Pat. As described in Patent No. 3860426, hydrophilic cellulose (e.g.,
A subbing layer of carboxymethyl cellulose, etc.) may also be provided. On the lithographic printing plate support according to the present invention,
A photosensitive lithographic printing plate can be obtained by providing a photosensitive layer conventionally known as a photosensitive layer of a PS plate,
The lithographic printing plate obtained by plate-making this has excellent performance. The compositions used in the photosensitive layer include the following. Photosensitive layer consisting of a diazo resin and a binder Reaction of a diazonium salt disclosed in the specifications of U.S. Pat. Condensation product of diphenylamine-p-diazonium salt and formaldehyde (so-called photosensitive diazo resin)
is preferably used. Other useful condensed diazo compounds are Japanese Patent Publications Nos. 49-48001, 49-45322, and 49-45322.
It is disclosed in various publications such as No. 49-45323. These types of photosensitive diazotized compounds are usually obtained in the form of water-soluble inorganic salts and can therefore be coated from an aqueous solution. Alternatively, these water-soluble diazo compounds can be reacted with an aromatic or resinous compound having one or more phenolic hydroxyl groups, sulfonic acid groups, or both by the method disclosed in Japanese Patent Publication No. 47-1167. It is also possible to use substantially water-insoluble photosensitive diazo resins which are reaction products. It can also be used as a reaction product with hexafluorophosphate or tetraroborate as described in JP-A-56-121031. In addition, diazo resins described in British Patent No. 1312925 are also preferred. Photosensitive layer made of an o-quinonediazide compound A particularly preferred o-quinonediazide compound is an o-quinonediazide compound.
Naphthoquinone diazide, for example, U.S. Patent No.
No. 2766118, No. 2767092, No. 2772972, No. 2859112, No. 2907665, No. 3046110,
Same No. 3046111, Same No. 3046115, Same No. 3046118,
Same No. 3046119, Same No. 3046120, Same No. 3046121,
Same No. 3046122, Same No. 3046123, Same No. 3061430,
Same No. 3102809, Same No. 3106465, Same No. 3635709,
It is described in numerous publications including the specifications of the same No. 3647443, and these can be suitably used. Azide compound and binder (photosensitive layer made of a polymer compound) For example, the specifications of British Patent No. 1235281 and British Patent No. 1495861, and JP-A-51-32331, British Patent No. 51-
In addition to the composition comprising an azide compound and a water-soluble or alkali-soluble polymer compound described in JP-A No. 36128, JP-A-50-5102, JP-A-50-84302,
Included are compositions comprising an azide group-containing polymer and a polymer compound as a binder, as described in Publications No. 50-84303 and No. 53-12984. Other photosensitive resin layers For example, polyester compounds disclosed in JP-A-52-96696, British Patent No. 112277,
Publication No. 1313309, Publication No. 1341004, Publication No. 1341004, Publication No. 1341004, Publication No.
Polyvinyl cinnamate resins described in specifications such as No. 1377747, U.S. Patent No. 4072528 and the same
The photopolymerizable photopolymer compositions described in each specification of No. 4072527 are included. The amount of photosensitive layer provided on the support is about 0.1 to about 7 g/m ² ,
Preferably it is in the range of 0.5 to 4 g/m ² . After the PS plate is image exposed, a resin image is formed by processing including development using conventional methods. For example, in the case of a PS plate having the photosensitive layer made of a diazo resin and a binder, after image exposure, the unexposed portions of the photosensitive layer are removed by a developer to obtain a lithographic printing plate. In the case of a PS plate having a photosensitive layer, after image exposure, the exposed portion is removed by developing with an alkaline aqueous solution to obtain a lithographic printing plate. (Example) Hereinafter, a more detailed explanation will be given based on an example. Example 1 Aluminum alloys No. 1 to No. 1 with the compositions shown in Table 1.
No. 12 was melted and cast, both sides were faceted to obtain an ingot with a thickness of 350 mm and a length of 2000 mm, which was soaked at a temperature of 560°C for 10 hours. This was heated and held at a temperature of 430℃ for 1 hour, then hot rolled at a temperature of 430℃ to 260℃ to a plate thickness of 4.0mm, and then further cold rolled to a plate thickness of 0.3mm (area reduction rate 92.5%). In this way, an aluminum alloy plate for lithographic printing plates was manufactured. Next, No. 1 to No. 12 aluminum alloy rolled plates and
No. 13 (plate thickness 0.30 mm JIS1050-H18 aluminum alloy) and No. 14 (plate thickness 0.30 mm JIS 1100-H16 aluminum alloy) were grained with a rotating nylon brush in a suspension of pumice stone and water, and then treated with caustic soda.
Using a 20% aqueous solution, the amount of aluminum dissolved is 5
It was etched so that it became g/ ^m2 . After thoroughly washing with running water, pickling was carried out with a 25% nitric acid aqueous solution, and the substrate was prepared by washing with water. The thus prepared substrate was subjected to alternating current electrolysis at a current density of 20 A/dm ² or more in an electrolytic bath containing 1.5% nitric acid as described in JP-A-54-146234. Subsequently, the surface was cleaned by immersion in a 50℃ aqueous solution of 15% sulfuric acid for 3 minutes, and then 20%
3 in an electrolytic solution containing sulfuric acid as the main component at a bath temperature of 30℃.
An oxide film of g/m ² was provided. The following photosensitive layer was provided on the sample prepared in the above manner so that the dry coating amount was 2.5 g/m ² . Ester compound of naphthoquinone-1,2-diazido-5-sulfonyl chloride, pyrogallol, and acetone resin (described in the Examples of US Pat. No. 3,635,709)...0.75g Cresol novolak resin...2.00g Oil Blue #603 (Orient Chemical)
...0.04g Ethylene dichloride ...16g 2-methoxyethyl acetate ...12g The photosensitive lithographic printing plate obtained in this way was brought into close contact with the transparent positive, and a PS light (Toshiba metal halide lamp MU2000-2-OL type 3KV was used) After exposure for 30 seconds with a 5% sodium silicate aqueous solution (sold by Fuji Photo Film Co., Ltd.), the sample No. .1 to No.14 were created. Tests were conducted on the uniformity of the electrolytically etched rough surfaces of Samples No. 1 to No. 14 prepared as described above, and the occurrence of stains and streaks in non-image areas. The results are shown in Table 1. (Test method) (1) Uniformity of electrolytically etched rough surface The surface condition was observed using a scanning electron microscope, and the uniformity of pits was evaluated. expressed. (2) Status of streak occurrence Visually observe the electrolytically etched rough surface, and mark 〇 if no streaks have occurred, mark △ if streaks have occurred in some areas, and mark × if streaks have occurred entirely. Ta. (3) Stain on non-image area After printing 100,000 copies using KOR offset printing machine,
The stain in the non-image area was evaluated, and excellent results were marked with ◯, good results with △ marks, and poor results with × marks. In addition, the amount of elemental Si in the metal structure is based on Japanese Patent Application Laid-open No. 60-
Quantitative analysis was performed using the analytical method described in No. 82642. As is clear from Table 1, the amount of elemental Si distributed inside all of the printing aluminum alloy plates No. 1 to No. 7 obtained by the method of the present invention is 0.012% or less,
It can be seen that all characteristics are satisfied in terms of uniformity of the electrolytically etched rough surface, stain resistance of non-image areas during printing, and streak resistance, and are superior to conventional JIS 1050 and 1100. On the other hand, aluminum alloy plates No. 8 to 12 with comparative alloy compositions outside the composition range of the aluminum alloy plates of the present invention have uniformity of the rough surface even when the amount of elemental Si distributed inside is 0.012% or less. It can be seen that some of the characteristics of dirt in the non-image area are inferior.

[Table] Example 2 The alloy ingot No. 2 in Table 1 in Example 1 was
After performing soaking treatment at a temperature of 550°C for 8 hours and cooling it under various cooling conditions shown in Table 2, it was hot rolled to a plate thickness of 4.5 mm, and further cold rolled to a plate thickness of 2.0 mm. , 20 at a temperature of 480℃ by continuous annealing furnace
An aluminum alloy plate for printing plates was produced by intermediate annealing for seconds and then cold rolling to a plate thickness of 0.3 mm. These were surface treated in the same manner as in Example 1,
Plate making was performed under the same conditions to create samples Nos. 15 to 24. The same tests as in Example 1 were conducted on these samples, and the results are shown in Table 2.

[Table] As is clear from Table 2, after soaking the ingot, it is cooled to a temperature of 430°C or less at an average cooling rate of 50°C/hour or less, and then hot rolled, cold rolled,
Intermediate annealing and cold rolling printing plate No. 15 according to the present invention
~19 has an elemental Si content of 0.012% distributed in the metal structure
It can be seen below that the uniformity of the rough surface, the stain resistance of the image area, and the streak resistance are excellent. On the other hand, the amount of elemental Si distributed in the metal structure is
It can be seen that in comparison printing plates Nos. 20 to 24 with a concentration exceeding 0.012%, that is, aluminum alloy plates for printing plates in which the cooling conditions after the soaking treatment were not corrected, stains in non-image areas were not improved and streaks also occurred. Example 3 Using the alloy ingot No. 2 in Table 1 in Example 1, it was soaked at 540°C for 8 hours, and then
After being held under the conditions shown in the table, it was hot rolled to a thickness of 3.5 mm, and then cold rolled to a thickness of 0.3 mm.
This was subjected to surface treatment in the same manner as in Example 1, and sample No.
Created 25-33. The same tests as in Example 1 were conducted on these, and the results are shown in Table 3.

[Table] As is clear from Table 3, after soaking treatment 350 ~
Printing plates No. 25 to 29 according to the present invention, which were kept at a temperature of 450°C for 30 minutes or more, all had an elemental Si content of 0.012% or less, and were excellent in uniformity of rough surfaces, staining in non-image areas, and streak resistance. I understand that. On the other hand, in comparison printing plates No. 30 to 33, in which the ingot retention conditions after soaking treatment are different, the elemental Si distributed in the metal structure exceeds 0.012%, indicating that the stain in the non-image area is not improved. . (Effects of the Invention) As described above, the lithographic printing plate support of the present invention has excellent rough surface uniformity, is less likely to cause stains in the non-image areas of printed matter, and can prevent the occurrence of streaks. It has remarkable effects as a lithographic printing plate that also has the following characteristics.

Claims (1)

[Claims] 1. An Al alloy plate consisting of 0.05 to 1% Fe, 0.2% or less Si, 0.05% or less Cu, and the balance being Al and inevitable impurities, wherein the elemental Si distributed in the metal structure is
An aluminum alloy support for a lithographic printing plate, characterized in that the content is 0.012% or less (wherein, % indicates weight %). 2 After soaking an aluminum alloy ingot consisting of Fe 0.05-1%, Si 0.2% or less, Cu 0.05% or less, and the balance Al and inevitable impurities, an average cooling rate of 50
℃/hour or less to a temperature of 430℃ or less, or
Or, hold at a temperature of 350 to 450℃ for 30 minutes or more, then hot-roll, or after hot-rolling, cold-roll and intermediate annealing, and then add final cold-rolling with an area reduction of 50% or more. A method for producing an aluminum alloy support for a lithographic printing plate, characterized in that the amount of elemental Si distributed in the metal structure of a cold-rolled plate is 0.012% or less (wherein, % indicates weight %) or less.