JPH0473394B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to a lithographic printing plate formed by roughening and anodizing, and further coating a photosensitive substance. The present invention relates to a method for producing an aluminum alloy support for a lithographic printing plate, which has excellent fatigue strength, has a uniformly roughened surface by electrochemical roughening treatment, and has a beautiful appearance with no streaks. (Prior Art) Conventionally, aluminum plates or aluminum alloy plates (hereinafter referred to collectively as aluminum plates) have been widely used as supports for lithographic printing, and as a typical printing plate, roughened There is a so-called PS board, which is made by coating a photosensitive material on an aluminum plate that has undergone surface treatments such as anodic oxidation coating and drying. Such aluminum plates for lithographic printing include JIS 1050 (pure Al with a purity of 99.5% by weight or more), JIS
1100 (Al-0.05~0.20wt% Cu alloy), JIS 3003
Aluminum plates having a thickness of 0.1 to 0.8 mm, such as [Al-0.05 to 0.20 wt% Cu-1.5 wt% Mn alloy (hereinafter, when expressing the composition, weight % is simply abbreviated as %)] are commercially available. Also, JP-A No. 58-42745, No. 59
There are aluminum plates disclosed in No. -133355, No. 60-5861, No. 60-63346, etc. Among these, aluminum alloy plates are generally lightweight, have excellent surface treatment properties, processability, and corrosion resistance, and have a hydrophilic surface, so they are used as supports for lithographic printing.
It is a particularly suitable material. This aluminum alloy plate has a surface mechanical method,
The surface is roughened by a surface roughening method using one or a combination of chemical methods, electrochemical methods, and then preferably subjected to anodizing treatment, and then finished by applying a photosensitizer to the surface. It will be done. The aluminum alloy plate coated with this photosensitizer is then subjected to plate-making processes such as exposure and development to form a printing plate with image areas formed, which is then wrapped around the cylindrical plate cylinder of a printing machine and adhered to the non-image areas. It is well known that the method is based on a mechanism in which ink is deposited on the printed area in the presence of dampening water, transferred to a rubber blanket, and printed on the paper surface. Therefore, aluminum alloy plates for printing plates are required to have the following basic properties. (1) In order to uniformly adhere the photosensitizer and improve adhesion, a uniformly roughened surface can be easily obtained, especially through electrochemical roughening treatment. (2) Due to electrochemical roughening treatment, streak structures (streak-like unevenness) do not occur and a beautiful appearance is achieved. (3) The plate is attached by bending both ends and wrapping it around the plate so that it is inserted into the groove of the cylindrical plate cylinder.Printing is carried out by applying ink to the plate rotating at high speed and then pressing it against a rubber blanket to transfer the ink. For,
The bent part is constantly subjected to repeated stress, and must have excellent fatigue resistance and tensile strength to withstand this. (4) The water retention capacity of the surface is sufficiently high to prevent staining of non-image areas. (Problems to be Solved by the Invention) However, in recent years, there has been a demand for aluminum alloy printing plates with higher standards in terms of the above characteristics. That is, as described in Japanese Patent Application Laid-Open No. 60-5861, in recent lithographic printing, the stress applied to printing plates increases due to high speed, long-run printing, etc., and they tend to easily fatigue. If the strength of the printing plate is insufficient, the parts fixed to the plate cylinder may be deformed or damaged, causing problems such as printing misalignment, or the plate may break due to repeated stress, resulting in poor tensile strength and fatigue strength. Further improvement is expected in this respect. In addition, as large numbers of copies are printed, requirements are becoming stricter in terms of stains in non-image areas, and it is necessary to improve the corrosion resistance of aluminum plates to prevent stains (for example, (See No. 1983-215727). Furthermore, when the above-mentioned electrochemical surface roughening treatment (for example, see JP-A-54-63902) is applied, streak-like unevenness called streaks may occur, impairing the aesthetic appearance and lowering the commercial value of the printing plate. many. This is because coarse recrystallized grains of 100 μm or more are generated between hot rolling passes, and their contours remain even after the final cold rolling, resulting in electrochemical surface roughening as a fibrous structure extending in the rolling direction. It appears through processing. However, the above-mentioned conventional aluminum plates have advantages and disadvantages as shown in the table below, and do not satisfy the above requirements.

[Table] (Means for solving the problems) The present inventors have conducted extensive research to overcome the drawbacks of conventional aluminum alloy planographic printing plate supports, and have found that Mg, Fe, Si, An aluminum alloy ingot containing a predetermined amount of Cu is subjected to predetermined soaking treatment, hot rolling, annealing, and then cold rolling,
By annealing and rapid cooling in a continuous annealing furnace, followed by final cold rolling, or by further temper annealing after final cold rolling, it is possible to obtain an aluminum alloy sheet that satisfies all of the above required properties. I found it. The present invention has been made based on this knowledge. That is, in the present invention, Mg0.35~0.9%, Fe0.05~
After soaking an aluminum alloy consisting of 0.5% Si, 0.2% Si or less, Cu 0.05% or less, and the balance Al and inevitable impurities, it is hot rolled and the hot rolled plate is
℃ for 30 minutes or more, then cold rolled, then heated in a continuous annealing furnace at a temperature of 460℃ or higher for less than 10 minutes, then cooled to 100℃ or less within 1 minute, and further reduced in area by 50% or more. A method for producing an aluminum alloy support for a lithographic printing plate, which is characterized by subjecting it to final cold rolling, and Mg0.35-0.9%, Fe0.05-0.5%, Si0.2
% or less, Cu 0.05% or less, and the remainder Al and unavoidable impurities.
Hot rolled and the hot rolled plate at a temperature of 300~520℃
After annealing for 30 minutes or more, cold rolling, then heating in a continuous annealing furnace at a temperature of 460℃ or higher for less than 10 minutes, then 100℃
After cooling within one minute to
Provided is a method for producing an aluminum alloy support for a lithographic printing plate, which comprises performing temper annealing at a temperature of 120 to 250°C for 30 minutes or more, or in a continuous annealing furnace at a temperature of 150 to 420°C for 120 seconds or less. It is something to do. First, each component in the aluminum alloy used in the present invention will be explained. Mg should be in the range of 0.35 to 0.9%. Mg is mostly
It dissolves in Al and improves tensile strength and fatigue strength without impairing the uniformity of the roughened surface created by electrochemical roughening treatment. If it is less than 0.35%, the tensile strength is low;
If it exceeds 0.9%, the uniformity of the rough surface will be impaired. Fe is in the range of 0.05 to 0.5%. Fe has the effect of making the electrolytically roughened surface uniform. Fe is an element that combines with other elements in aluminum alloys to form Al-Fe or Al-Fe-Si eutectic compounds, and these eutectic compounds are effective in refining recrystallized grains. At the same time, there is an effect of forming a uniformly fine electrolytically rough surface. If the Fe content is less than 0.05%, the effect of finer recrystallized grains and uniform fineness of the electrolytically roughened surface will be small, and if the Fe content exceeds 0.5%, the electrolytically roughened surface will be adversely affected due to the formation of coarse compounds. Becomes non-uniform. 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 stains in non-image areas are likely to occur. Cu shall be 0.05% or less. Cu is included as a normal impurity, and when it exceeds 0.05%, the uniformity of the rough surface is impaired and stains in non-image areas are likely to occur. Unavoidable impurities in the alloy used in the present invention include Mn, Cr, Zn, etc., and their content is 0.05
There is no problem if it is less than %. Furthermore, in the present invention, it is preferable to add Ti and B to refine the ingot structure. The amount added is
Suitable values are Ti 0.05% or less and B 0.01% or less. Next, a method of processing the above aluminum alloy will be explained. First, the molten metal with the above composition is cast in the usual manner and soaked (preferably at 450-600℃ for 3 hours or more).
Then, hot rolling is performed. It is desirable that hot rolling be carried out at a temperature of 500 to 200°C. This hot rolled plate is 300 ~
Anneal at a temperature of 520℃ for more than 30 minutes to completely recrystallize. At this time, the temperature is less than 300℃ or the time is 30℃.
If the temperature is less than 520°C, recrystallization will be insufficient, and if it exceeds 520°C, the crystal grains will become coarse, which is inappropriate. Next, after cold rolling (preferably 20% or more), heating to a temperature of 460°C or more in a continuous annealing furnace,
After holding for 10 minutes or less, rapidly cool to a temperature below 100℃ within 1 minute. This heating causes Mg, Si,
Alloying elements such as Cu are re-dissolved and can improve the uniformity of the roughened surface and the strength in electrochemical roughening treatment. At the same time, this heating generates fine recrystallization (grain size of 30 μm or less). The recrystallization annealing treatment performed immediately after hot rolling and the main recrystallization treatment performed in a continuous furnace after cold rolling are performed to completely eliminate the outline of coarse grains generated between hot rolling passes. In other words, by obtaining fine recrystallized grains with completely random orientation,
This is to eliminate any streak structure in the cold rolled plate. The reason why the heating conditions using the continuous furnace were specified as described above is as follows. In other words, at temperatures below 460°C, the re-solid solution effect of alloying elements is not sufficient, and 1
If the holding time exceeds 10 minutes, the recrystallized grains will grow coarsely, impairing the uniformity of the rough surface. The purpose of cooling to a temperature of 100° C. or lower within 1 minute is to suppress the generation of precipitates such as elemental Si that impair the stain resistance of the non-image area as much as possible. The plate thus obtained is cold rolled so that the reduction in area is 50% or more. In this final cold rolling, the Al-Fe-based and Al-Fe-Si-based eutectic compounds are dispersed, and the crystal structure becomes uniform. This area reduction rate
If it is less than 50%, the compound will be insufficiently dispersed and the crystal structure will be non-uniform, making it impossible to obtain a uniformly roughened surface in surface roughening treatment. The cold-rolled sheet thus obtained can sufficiently achieve the purpose of the present invention as it is, but if the fatigue strength is to be further improved, it may be subjected to temper annealing as described below. is valid. That is, in a batch furnace 120
At a temperature of ~250℃, more than 30 minutes, preferably 60-300℃
Rapid temper annealing is performed for 120 seconds or less, preferably for 5 to 60 seconds, at a temperature of 150 to 420°C in a continuous annealing furnace. If the temperature of the above-mentioned temper annealing conditions is less than 120℃ when using a batch furnace or the treatment time is less than 30 minutes, sufficient fatigue strength improvement effect will not be obtained, and if it exceeds 250℃, recrystallization phenomenon will occur. , tensile strength and fatigue strength decrease. When performing temper annealing in a continuous annealing furnace, a sufficient fatigue strength improvement effect cannot be obtained at temperatures below 150℃, and temperatures exceeding 420℃ or
If the treatment time exceeds 120 seconds, the tensile strength and fatigue strength will decrease. The aluminum alloy plate for lithographic printing plates of the present invention manufactured as described above is subjected to surface roughening treatment to meet JIS standards.
It has a uniform pit shape and appropriate surface roughness equivalent to 1050 aluminum alloy, has excellent water retention and stain resistance in non-image areas, and has tensile strength and fatigue strength equivalent to or higher than JIS 3003 aluminum alloy. Above, it has a beautiful appearance with no streaks observed at all. 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 the grain is electrochemically grained 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 a polishing ball and a polishing agent. Mechanical graining methods such as the ball grain method, which grains the surface, and the brush grain method, which grains the surface with 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, 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. A condensation product of diphenylamine-p-diazonium salt and formaldehyde (so-called photosensitive diazo resin) is preferably used. Other useful condensed diazo compounds are listed in Japanese Patent Publication No. 49-48001,
It is disclosed in the publications No. 49-45322 and No. 49-45323. These types of photosensitive diazo compounds are usually obtained in the form of water-soluble inorganic salts and can therefore be coated from 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. 1167/1983. It is also possible to use substantially water-insoluble photosensitive diazo resins which are reaction products. Also, JP-A-56-
It can also be used as a reaction product with hexafluorophosphate or tetraroborate as described in JP 121031. In addition, diazo resins described in British Patent No. 1312925 are also preferred. Photosensitive layer made of o-quinonediazide compound Particularly preferred o-quinonediazide compound is o-quinonediazide compound.
- naphthoquinone diazide compounds, such as U.S. Patent Nos. 2766118, 2767092,
No. 2772972, No. 2859112, No. 2907665,
Same No. 3046110, Same No. 3046111, Same No. 3046115
No. 3046118, No. 3046119, No. 3046119, No. 3046118, No. 3046119, No.
No. 3046120, No. 3046121, No. 3046122,
Same No. 3046123, Same No. 3061430, Same No. 3102809
No. 3106465, No. 3635709, No. 3635709, No. 3106465, No. 3635709, No.
It is described in numerous publications including the specifications of 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 Japanese Patent Publication No. 50-5102 and Japanese Patent Application Laid-open No. 50-50-
Included are compositions comprising an azide group-containing polymer and a polymer compound as a binder, as described in Publications No. 84302, 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
No. 1313309, No. 1341004,
Included are polyvinyl cinnamate resins described in U.S. Pat. No. 1,377,747 and other specifications, and photopolymerizable photopolymer compositions described in U.S. Pat. The amount of photosensitive layer provided on the support is approximately
It ranges from 0.1 to about 7 g/ ^m2 , preferably from 0.5 to 4 g/ ^m2 . 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,
Unexposed portions of the photosensitive layer are removed by development to obtain a lithographic printing plate. Also has a photosensitive layer
In the case of a PS plate, after image exposure, the exposed portion is removed by developing with an alkaline aqueous solution to obtain a lithographic printing plate. (Examples) Hereinafter, the present invention will be explained in more detail based on Examples. Example 1 Aluminum alloys No. 1 to No. 1 with the compositions shown in Table 1.
No. 12 was melted and cast, and both sides were face-milled to obtain an ingot with a thickness of 350 mm and a length of 2000 mm, which was soaked at a temperature of 550°C for 10 hours. This was hot rolled at a temperature of 450 to 250℃ to a plate thickness of 4.5mm, and then heated to 420mm in a batch furnace.
The sample was annealed for 4 hours at a temperature of 20°C to completely recrystallize it (heating rate 50°C/hour, cooling rate 20°C/hour). After cold rolling this to a plate thickness of 1.8 mm (area reduction rate of 60%),
After annealing at 500°C for 10 seconds in a continuous annealing furnace to completely recrystallize the material, it was rapidly air cooled to 100°C for 12 seconds. This was further subjected to final cold rolling to a thickness of 0.3 mm (area reduction rate: 83.3%) to obtain an aluminum alloy plate for lithographic printing. Next, No. 1 to No. 12 aluminum alloy rolled plates and
No.13 (0.30mm JIS 1050-H18 aluminum alloy plate), No.14 (0.30mm JIS 1100-H16 aluminum alloy plate), and No.15 (0.30mm JIS 3003-H14 aluminum alloy plate) with pumice stones. After graining with a rotating nylon brush in a water suspension,
Etching was performed using a 20% aqueous solution of caustic soda so that the amount of aluminum dissolved was 5 g/m ² . After thoroughly washing with running water, pickling with 25% nitric acid aqueous solution,
The substrate was prepared by washing with water. The substrate prepared in this manner is subjected to a current density in an electrolytic bath containing 0.5 to 2.5% nitric acid as described in Japanese Patent Application Laid-open No. 146234/1983.
AC electrolysis was performed at 20 A/dm ² or higher. Continued 15%
After cleaning the surface by immersing it in a 50°C aqueous solution of sulfuric acid for 3 minutes, an oxide film of 3 g/m ² was formed in an electrolytic solution containing 20% sulfuric acid as a main component at a bath temperature of 30°C. The photosensitive layer described below was provided on the sample prepared in this 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 thus obtained was brought into close contact with the transparent positive image and exposed from a distance of 1 m using a PS light (Toshiba metal halide lamp MU2000-2-OL type 3KV). The film was exposed for 30 seconds using a light source (sold by Fuji Photo Film Co., Ltd.), and then developed by immersing it in a 5% by weight aqueous sodium silicate solution for about 1 minute.
Samples No. 1 to No. 15 were prepared by washing with water and drying. Tests were conducted on the uniformity of the electrolytically etched rough surfaces, stains in non-image areas, fatigue strength, and static strength of Samples No. 1 to No. 15 thus prepared. The test method is as follows. The results are shown in Table 1. (Test method) (1) Uniformity of electrolytically etched rough surface The surface condition was observed with a scanning electron microscope and the uniformity of pits was evaluated. expressed. (2) Smudges in non-image areas After printing 100,000 copies using the offset printing machine KOR, the smudges in non-image areas were evaluated. Excellent ones are marked with ○, good ones are marked with △, and poor ones are marked with ×. expressed. (3) Fatigue strength Cut out a test piece with a width of 20 mm and a length of 100 mm from each sample, fix one end to a jig, bend the other end upward at an angle of 30°, return it to its original position, and The number of times until breakage was measured, with 1 time being counted as one time. (4) Static strength A JIS No. 5 test piece was prepared from the sample, and the tensile strength, 0.2% yield strength, and elongation rate were measured by a tensile test. (5) Status of streak occurrence Visually observe the surface after electrolytic etching, and mark ○ if no streaks have occurred at all, mark △ if streaks have occurred partially, and mark × if streaks have occurred over the entire surface. Represented by a mark.

【table】

[Table] As is clear from Table 1, the aluminum alloy plates No. 1 to No. 7 for printing plates obtained by the method of the present invention have uniformity of the electrolytically etched rough surface, streak property, and non-image area during printing. It satisfies all properties in terms of stain resistance, fatigue strength, and tensile strength, and exceeds the conventional JIS
It can be seen that it is better than 1050, 1100 and 3003. In contrast, aluminum alloy plates No. 8 to 12 with comparative alloy compositions outside the composition range of aluminum alloy plates in the method of the present invention have poor uniformity of the rough surface, staining of non-image areas during printing, fatigue strength, and tensile strength. It can be seen that these characteristics are inferior. In other words, No. 8, which has a low Mg content, has good rough surface uniformity and good staining in non-image areas during printing, but has poor tensile strength.
Samples No. 9 to No. 11 with high contents of Mg, Si, and Fe had good fatigue strength and tensile strength, but were poor in rough surface uniformity and staining of non-image areas during printing. In addition, No. 12, which has a large amount of Cu, has poor uniformity of the rough surface and poor stain resistance in non-image areas during printing. Example 2 Using the alloy ingot No. 2 in Table 1 in Example 1, soaking treatment was performed at a temperature of 560°C for 8 hours,
This was hot rolled at 480 to 300°C to a plate thickness of 5.0 mm.
Furthermore, annealing, cold rolling, annealing/cooling in a continuous furnace, final cold rolling, and temper annealing were performed under various conditions shown in Table 2. The aluminum alloy plate for printing plates produced in this way was subjected to surface treatment in the same manner as in Example 1,
Plate making was performed under the same conditions to create samples Nos. 16 to 28. The same tests as in Example 1 were conducted on these samples, and the results are shown in Table 2.

【table】

[Table] As is clear from Table 2, the aluminum alloy plates No. 16 to No. 21 for printing plates produced by the method of the present invention have good uniformity of the electrolytically etched rough surface, streak resistance, and stain resistance in non-image areas. It has excellent fatigue strength and tensile strength. In contrast, No. 22, which is not annealed after hot rolling.
In No. 23, where the annealing conditions were not met, leakage occurred. In addition, No. 24, No. 25, and No. 26, which were not heated and cooled in a continuous furnace, were inferior in either the uniformity of the rough surface or the staining of the non-image area. In addition, No. 27, which is out of temper annealing conditions, has poor fatigue and tensile strength, and No. 28, which has a low area reduction, has poor strength and rough surface uniformity. (Effects of the Invention) As described above, the support for a lithographic printing plate obtained by the method of the present invention has excellent uniformity of the rough surface, is resistant to staining in non-image areas, and can prevent the occurrence of streaks. Furthermore, since it has excellent fatigue strength and tensile strength, it has the remarkable effect of making it possible to provide a lithographic printing plate that has both of these properties. Further, in the present invention, after final cold rolling,
Furthermore, a support for a lithographic printing plate with particularly high fatigue strength can be obtained by applying annealing to a predetermined temperature.

Claims (1)

[Claims] 1 Mg0.35-0.9%, Fe0.05-0.5%, Si0.2% or less, Cu0.05% or less (the above percentages indicate weight%),
After soaking an aluminum alloy consisting of the remaining Al and unavoidable impurities, it is hot-rolled, and the hot-rolled plate is annealed at a temperature of 300 to 520°C for 30 minutes or more, then cold-rolled, and then in a continuous annealing furnace. 10 at temperatures above 460℃
1. A method for producing an aluminum alloy support for a lithographic printing plate, which comprises heating for less than 1 minute, cooling to 100° C. or less within 1 minute, and then final cold rolling with an area reduction of 50% or more. 2 Mg0.35-0.9%, Fe0.05-0.5%, Si0.2% or less, Cu0.05% or less (the above percentages indicate weight%),
After soaking an aluminum alloy consisting of the remaining Al and unavoidable impurities, it is hot-rolled, and the hot-rolled plate is annealed at a temperature of 300 to 520°C for 30 minutes or more, then cold-rolled, and then in a continuous annealing furnace. 10 at temperatures above 460℃
After being heated for less than 1 minute, cooled to 100℃ or less within 1 minute, and then subjected to final cold rolling with an area reduction of 50% or more, and then further heated in a batch furnace at a temperature of 120 to 250℃.
150 to 420 for more than 30 minutes or in a continuous annealing furnace
1. A method for producing an aluminum alloy support for a lithographic printing plate, characterized by subjecting it to thermal annealing at a temperature of 120 seconds or less at a temperature of ℃.