JPS63135294A - Aluminum alloy substrate for lithographic plate and production thereof - Google Patents

Abstract

PURPOSE:To obtain a uniform electrolytic roughened surface with a little quantity of charge electricity and to improve a lithographic plate in plate wear and resistance to stains on non-image areas in printing, by using an aluminum alloy containing Fe, Mg, Sn, Si, and Cu in specific ratios with the content of simple Si less than a specific amount. CONSTITUTION:The composition of an aluminium alloy substrate for lithographic plate is determined as follows: 0.05-0.5% of Fe, 0.7-5% of Mg, 0.01-0.2% of Sn, 0.2% or less of Si, and 0.05% or less of Cu are contained, the remainder is made of Al and an unavoidable impurities, and simple Si is contained 0.012% or less. The impurities of 0.05% or less of Mn, 0.05% or less of Cr, and 0.05% or less of Zn contained in the aluminum alloy cause no particular problem. A uniform roughened surface can be formed by applying electrochemical surface- roughening treatment to the substrate with a little quantity of electricity. In addition, a lithographic plate making use of the substrate is superior in resistance to stains on non-printing areas in printing as well as in plate wear and strength.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is used for a lithographic printing plate formed by subjecting the surface of a roughened aluminum alloy plate to an anodic oxidation film treatment and further coating a photosensitive substance. It is related to supports that can be electrochemically roughened with a small amount of electricity, has excellent stain resistance in non-image areas during printing, and has excellent strength and printing durability. The present invention relates to an aluminum alloy support that provides an excellent lithographic printing plate and a method for manufacturing the same.

(Prior Art) Conventionally, as a lithographic printing plate, an aluminum plate coated with a photosensitive substance has been used, which has been subjected to surface treatments such as roughening treatment and anodized coating treatment. The most widely used of these is the so-called 23 plate, which is coated with a photosensitive material in advance and is ready for printing immediately.

A printing plate is obtained by subjecting such a lithographic printing plate to plate-making processes such as image exposure, development, water washing, and lacquer application, but the undissolved photosensitive layer due to this development process forms an image area, and the photosensitive layer is removed. The exposed portion of the aluminum surface underneath is hydrophilic, so it becomes a water receiving area and forms a non-image area.

As a support for such lithographic printing plates, aluminum plates are generally used, which are lightweight and have excellent surface treatment properties, workability, and corrosion resistance. Conventional materials used for this purpose include JIS
1050 (Pure Al with a purity of 99.5% by weight or more), J
IS 1100 (Al-0.05~0.20% by weight
Cu alloy) JIS 3003 (A l -0.05 ~
There are aluminum alloy plates having a thickness of 0.1 to 0.811 m, such as 0.20 wt% Cu-1,5 wt% Mn alloy). The surface of this aluminum alloy plate is roughened by a mechanical method, a chemical method, an electrochemical method, or a combination of two or more steps, and then preferably anodized. used.

Specifically, an aluminum lithographic printing plate subjected to mechanical roughening treatment, chemical etching treatment, and anodic oxide film treatment described in JP-A-48-49501, or JP-A-51-61304. Aluminum lithographic printing plates were subjected to chemical etching treatment and anodic oxide film treatment as described in the publication, and electrochemical treatment, post-treatment, and anodic oxide film treatment were performed as described in JP-A-54-146234. Aluminum lithographic printing plate, Special Publication 1977-
Aluminum lithographic printing plate subjected to electrochemical treatment, chemical etching treatment, and anodic oxide film treatment described in Japanese Patent Publication No. 28123, and mechanical roughening treatment described in Japanese Patent Application Laid-Open No. 54-63902. Aluminum lithographic printing plates are known which have been sequentially subjected to chemical etching treatment, electrochemical roughening treatment, and the like. By appropriately selecting the photosensitive layer coated on such a support, lO
It is possible to obtain an aluminum lithographic printing plate that can withstand printing of up to 10,000 sheets.

In particular, when electrochemical surface roughening treatment is applied to aluminum alloy plates, lithographic printing plates with good printing durability, tone reproducibility, and water retention can be obtained, and the rough surface morphology can also be controlled. Because it is easy and suitable for mass production, it is widely used industrially.

Conventionally, in addition to the JIS 1050 alloy plate mentioned above, aluminum alloy plates suitable for electrochemical surface roughening treatment include ■F
e0.35 to 1% by weight (hereinafter, weight% is abbreviated as %)
, Aluminum alloy plate prepared by homogenizing an aluminum alloy containing 0.2% Si or less, followed by hot rolling and 40 to 80% cold rolling (Japanese Patent Application Laid-Open No. 55-28874), ■Fe
0.1-1.0%, Si 0.02-0.15%,
Aluminum alloy plates containing 0.003% or less of Cu (Japanese Patent Application Laid-open No. 58-221254) have been proposed, and aluminum alloy plates containing a predetermined amount of Fe and Si have been proposed in Japanese Patent Application Laid-Open No. 58-42493 and the same. No. 59-67349.

(Problems to be Solved by the Invention) When the above-mentioned conventional aluminum alloy plate for lithographic printing plates is used, a uniformly roughened surface can be obtained by electrochemical surface roughening treatment.

However, with the rise in electricity costs in recent years, there has been a desire to reduce the amount of electricity input during electrochemical surface roughening treatment to save energy and cost.

However, when the amount of electricity applied to the above-mentioned conventional aluminum alloy plate is reduced, the surface is not sufficiently roughened and some unetched areas remain, reducing the adhesion with the photosensitive material, which reduces the printing life of the aluminum lithographic printing plate. The drawback was that the power deteriorated.

In addition, when printing a large number of copies (more than the number of copies), the conventional aluminum alloy support loses its parent property due to local corrosion, and ink adheres to the non-image area and stains the printed matter. There was a problem that something happened. This local corrosion is caused by the fact that the presence of elemental Si inside the aluminum alloy plate impairs the integrity of the film due to anodizing treatment, and that the presence of elemental Si inside the aluminum alloy plate impairs the integrity of the film, and that the relationship between elemental Si and matrix (aluminum) It turned out that this was caused by a local battery reaction occurring due to the potential difference. The above conventional JIS
In the case of 1050 alloy plates and the like, elemental Si is likely to be generated using normal manufacturing methods, so that stains may occur in non-image areas, especially when printing a large number of copies.

Furthermore, as printing speeds have increased with the advancement of printing technology, the stress applied to printing plates that are mechanically fixed to both ends of the plate cylinder of a printing press tends to increase. Therefore, if the tensile strength of the printing plate is insufficient, this fixed portion may be deformed or damaged, causing problems such as printing misalignment, and often making printing impossible. Conventional JIS 1050 alloy plates have low tensile strength and are prone to such failures, and 3003
Although alloy plates and the like have sufficient tensile strength, they have poor electrolytic surface roughening properties and have the drawback of easily staining non-image areas.

Therefore, the object of the present invention is to be able to form a uniformly roughened surface by performing electrochemical surface roughening treatment with a small amount of electricity, to improve stain resistance of non-image areas during printing, and to improve printing durability and strength. An object of the present invention is to provide an aluminum alloy support that provides an excellent lithographic printing plate.

(Means for Solving the Problems) The above object of the present invention is to reduce Fe 0.05 to 0.5%, Mg
0.7-5%, Sn 0.01-0.2%, Si0.
2% or less, Cu, 0.05% or less, the balance consists of Al and unavoidable impurities, and elemental Si is 0.012%
This was achieved by using an aluminum alloy support for lithographic printing plates, which is characterized in that it is less than %.

The reason why the composition of the support is limited as described above in the present invention is as follows.

Fe is an element that combines with other elements in aluminum alloys to form A-cross-Fe system or Al-Fe-Si system eutectic compounds, and these eutectic compounds are effective in refining recrystallized grains. If the content is less than 0.05%, the effect of refining recrystallized grains and uniformly refining the electrolytically roughened surface will be small, or 0.05%.
If the content exceeds 5%, the electrolytically roughened surface will become non-uniform due to the formation of coarse compounds.

Mg has the effect of improving strength without adversely affecting electrochemical roughening treatment. If it is less than 0.7%, the effect is not sufficient, and if it exceeds 5%, the strength will be too high.
Not only will it be difficult to attach it to the plate cylinder, but the stain resistance of non-image areas will also be poor.

Sn is added in order to accelerate the electrolytic etching rate in the electrochemical surface roughening treatment and to obtain a uniform, finely roughened surface having an appropriate surface roughness with a small amount of electricity. Sn is mostly dissolved in solid solution and partially forms a fine intermetallic compound of Mg-3n type. It is estimated that this solid solution Sn has the effect of accelerating the etching rate and improving the uniformity of etching due to the Mg-5n-based fine intermetallic compound. However, if it exceeds 0.2%, Sn will exist as a simple substance, which will actually impair the uniformity of the rough surface.

The content of Si is 0.2% or less. Si is contained 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 why Cu is limited to 0.05% or less is because C is an impurity.
This is because if u exceeds 0.05%, the pits generated by electrochemical surface roughening treatment tend to become coarse and the stain resistance of non-image areas also deteriorates.

In addition, the amount of elemental Si in the final cold-rolled plate was set to 0.01
The reason for limiting the content to 2% or less is that elemental Si remains in the anodic oxide film after anodizing treatment and forms film defects, which become the starting point for staining in non-image areas during printing. By regulating the amount of elemental Si, which is present in non-solid solution and does not impair the properties, to 0.012% or less, it is possible to obtain a printing plate with extremely excellent printability that is less likely to cause stains in non-image areas. This is what I discovered.

The object of the present invention will not be impaired if the impurities contained in the aluminum alloy constituting the lithographic printing plate support in the present invention are at the level of impurities contained in commercially available Al ingots.

That is, Mn 0.05% or less, Cr 0.05% or less, ZnO
There is no particular problem if it is 605% or less.

In addition, when manufacturing ingots, Ti and B, which are usually used as crystal refining agents, contain less than 0.05% of Ti and 0.0% of B.
Addition of 1% or less is effective in making the alloy structure uniform and fine.

The production of the aluminum alloy support for lithographic printing plates of the present invention includes Fe 0.05-0.5%, Mg 0.7-5%, S
n0. Old ~0.2%, Si0.2% or less, CuO805
% or less, the remainder AI and unavoidable impurities are soaked and then cooled to a temperature of 430°C or less at an average cooling rate of 50°C/hour or less, or 350 to 450°C. After holding at a temperature of 30 minutes or more, hot rolling or after hot rolling, cold rolling and intermediate annealing are performed, followed by final cold rolling with an area reduction rate of 50% or more. This can be done by controlling the content to 0.012% or less.

In manufacturing this lithographic printing support, an aluminum alloy ingot having the above composition is subjected to soaking treatment to dissolve impurities and a portion of Fe into a solid solution, and a portion of the intermetallic compound of Fe is uniformly and finely dispersed. let This scorching heat treatment is 500-6
It is desirable to carry out the treatment at a temperature of 20°C for 3 hours or more. This is then cooled at an average cooling rate of 50°C/hour or less until it reaches a temperature of 430°C or less, or
By holding the ingot at a temperature of 30 minutes or more, the Si atoms contained in the ingot are precipitated as an Al1-Fe-5i intermetallic compound, thereby reducing the amount of elemental Si precipitated in subsequent steps. Furthermore, since this Al-Fe-3i gold metal 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. At this time, a part of Sn combines with Mg and becomes Mg Sn
Since it precipitates uniformly as a fine intermetallic compound, it has the effect of improving the uniformity of electrochemical surface roughening treatment, as described above.

Thereafter, hot rolling is carried out in a conventional manner, or cold rolling and intermediate annealing are performed after hot rolling. Hot rolling temperature is 450-200
It is appropriate to carry out the test at ℃. Hot rolling start temperature 450°
When C is exceeded, the recrystallized grains between hot rolling passes become coarse, 1100p or more, and streaks are likely to occur in the final cold rolled sheet. Intermediate annealing after hot rolling, if necessary, is 35
It is preferable to perform the annealing at 0 to 500°C for 2 to 5 hours or in a continuous annealing furnace at 400 to 550°C for 120 seconds or less.

The plate thus obtained is finally cold-rolled to have an area reduction of 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, resulting in a non-uniform crystal structure, and a uniform roughened surface will not be obtained in the surface roughening treatment.

In addition, in order to impart appropriate ductility to this final cold-rolled plate and improve fatigue strength, precipitation of elemental Si does not occur.
Temperature annealing may be performed under the following conditions. Temperature annealing is performed at 70 to 180°C at 30°C in a normal batch furnace.
It is appropriate to do this for more than a minute. It is not very effective at temperatures below 70°C or for less than 30 minutes, and at temperatures above 180°C, single S
i precipitation occurs, 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-time heating, in which case the temperature is 150 to 400°C and 120°C.
It is appropriate to heat it for less than a second. If the heating time is less than 150°C, the effect will be insufficient, if it exceeds 400°C, the plate will become too soft, and if the heating time is longer than 120 seconds, the productivity will be poor.

The cold-rolled plate thus obtained contains 0.012% or less of elemental Si inside. If this cold-rolled plate is electrochemically roughened, a uniformly roughened surface can be obtained with a small amount of electricity. Using this roughened aluminum alloy plate as a support, it has excellent stain resistance in non-image areas during printing.
Furthermore, it is possible to obtain a lithographic printing plate with excellent strength and printing durability.

Next, the method for surface treatment of the aluminum alloy support for lithographic printing plates of the present invention will be explained in detail.

The graining method (surface roughening treatment method) for producing the aluminum alloy support of the present invention is preferably an electrochemical graining method in which the aluminum surface is grained electrochemically in a hydrochloric acid or nitric acid electrolyte. Mechanical graining methods such as the wire brush grain method, which uses a fully bent wire to grain the aluminum surface, the pole grain method, which grains the aluminum surface using a polishing method and an abrasive, and the brush grain method, which grains the surface with a nylon brush and abrasive. These graining methods can also be used alone or in combination.

Aluminum grained in this way.

If necessary, it is chemically etched with acid or alkali. When an acid is used as an etching agent, it takes a very long time to destroy the fine structure, which is disadvantageous when applying the present invention industrially, or it 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, aluminate sorter, metasilicate sorter, sodium phosphate, potassium hydroxide, lithium hydroxide, etc., and the preferred range of concentration and temperature is 1 to 50% for each. ,
The temperature is 20-100℃, and the amount of dissolved Al is 5-20g/r.
Preferably, the conditions are such that n'.

After etching, pickling is performed to remove any dirt (smuft) remaining on the surface. The acid used is nitric acid,
Sulfuric acid, phosphoric acid, chromic acid, sulfuric acid, hydrofluoric acid, etc. are used. In particular, the smut removal treatment after the electrochemical surface roughening treatment is preferably performed at a temperature of 50 to 90'C as described in JP-A-33-12739.
Method of contacting with 65% by weight sulfuric acid and Japanese Patent Publication No. 48-2
This is an alkali etching method described in Japanese Patent No. 8123.

Although the aluminum plate treated as described above can be used as a support for a lithographic printing plate, 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 direct or alternating current is passed through aluminum in an aqueous or non-aqueous solution using sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, etc. or a combination of two or more of these acids, aluminum is supported. It is possible to form an anodic oxide film on the body surface.

The processing conditions for anodic oxidation vary depending on the electrolytic solution used, so they cannot be determined unconditionally, but generally the electrolytic solution concentration is 1 to 80%, the solution temperature is 5 to 70°C, and the current density is 0.
A range of 5 to 60 amperes/dm', a voltage of 1 to 100 V, and an electrolysis time of 10 to Zoo seconds is appropriate.

Among these anodic oxide coating treatments, the British Patent No. 1,
No. 412,768, the invention uses a method of anodizing in sulfuric acid at high current density, and U.S. Pat. A method of anodizing as a bath is preferred.

The anodized aluminum plate is further covered by U.S. Patent No. 2,
Alkali metal silicates, as described in the specifications of No. 714,066 and No. 3,181°461;
For example, woody cellulose containing water-soluble metal salts (such as zinc acetate) may be treated by methods such as immersion in an aqueous solution of sodium silicate, or as described in U.S. Pat. No. 3,860,426. A subbing layer (eg, carboxymethyl cellulose) may also be provided.

A photosensitive layer conventionally known as a photosensitive layer of a PS plate can be provided on the support for a lithographic printing plate according to the present invention to obtain a photosensitive lithographic printing plate.

The lithographic printing plate obtained by plate-making this material has excellent properties.

The composition of the photosensitive layer includes the following.

■Photosensitive layer consisting of diazo resin and binder Diazonium salt and reactive carbonyl group such as aldol or acetal disclosed in U.S. Patent Nos. 2,063,631 and 1,667,415 A condensation product (so-called photosensitive diazo resin) of diphenylamine-p-diazonium salt, which is a reaction product with an alit mixture containing formaldehyde, is preferably used. Other useful condensed diazo compounds are listed in Japanese Patent Publication No. 49-48001.
No. 49-45322, No. 49-45323, etc.

These types of photosensitive diazo compounds are usually obtained in the form of water-soluble inorganic salts and can therefore be applied by aqueous coating.

Or these water-soluble diazo compounds are
A substantially water-insoluble photosensitive product obtained by reacting with an aromatic or aliphatic compound having one or more phenolic hydroxyl groups, sulfonic acid groups, or both by the method disclosed in Publication No. 7 Polymeric diazo resins can also be used. It can also be used as a reaction product with hexafluorophosphorus #salt or tetrafluoroborate as described in JP-A-56-121031. In addition, diazo resins described in British Patent No. 1,312,925 are also preferred.

(2) Photosensitive layer made of 0-quinonediazide compound Particularly preferred 0-quinonediazide compounds are 〇-naphthoquinone cyasito compounds, such as U.S. Pat. No. 2,766.118, U.S. Pat. 972
No. 2,859,112, No. 2,907,66
No. 5, No. 3,046,110, No. 3゜046.1
No. 11, No. 3,046,115, J3, 046
, No. 118, No. 3,046.119, No. 3,0
No. 46,120, No. 3.046,121, No. 3
, 046゜122, 3,046,123, 3.061,430, 3,102,809, 3,106,465, 3,635.709 ,
It is described in many publications including the specification of the same No. 3,647,443, and these can be used suitably.

■Acid compound and binder (photosensitive layer consisting of a polymer compound) For example, British Patent No. 1,235,281, British Patent No. 1,49
In addition to the compositions comprising an azide compound and a water-soluble or alkali-soluble polymer compound described in the specifications of No. 5,861 and JP-A-51-32331 and JP-A-51-36128, JP-A-Sho. No. 50-5102, 50-
No. 84302, No. 50-84303, No. 53-129
Included are compositions comprising a polymer containing an azide group and a polymer compound as a binder, as described in each publication of No. 84.

■Other photosensitive resin layers For example, polyester compounds disclosed in JP-A-52-96696, British Patent No. 112.277, British Patent No. 1,313,309, British Patent No. 1,341,004.
Polyvinyl cinnamate-based resins described in specifications such as No. 1, No. 1,377,747, and U.S. Patent No. 4.07
The photopolymerizable photopolymer compositions described in the specifications of No. 2,528 and No. 4,072,527 are included. The amount of publication layer provided on the support is approximately 0.1
~7 g/rn', preferably o, 5-4 g/rn'
is within the range of

After the PS plate is exposed to an image, a resin image is formed by a conventional process including development. For example, in the case of a PS plate having the photosensitive layer (1) made of a diazo resin and a binder, after image leakage, the photosensitive layer in the unexposed area is removed by development to obtain a lithographic printing plate. In the case of a pS plate having a photosensitive layer (1), after image exposure, the exposed portion is removed by developing with an alkaline aqueous solution to obtain a lithographic printing plate.

After the development treatment, the printing plate is subjected to appropriate post-treatments as desired.

In post-processing, the most relevant process is burning for enhancement of image parts. Regarding burning, for example, JP-A-52-6205, JP-A-51-34001
No., Special Publication No. Sho 55-28062, Special Publication No. Sho 57-3
Although it is described in Japanese Patent No. 938 and US Pat. No. 4,191,570, burning is basically a process of placing a developed printing plate in an atmosphere with a temperature of 1.50 to 350°C. The image part of the image is sintered and hardened.

In this case, before or after burning, for example, use boric acid or borium! It is preferred to provide the print with an aqueous solution of a salt, anionic surfactant or other compound having a specific chemical structure.

Thereby, various harmful effects caused by burning can be prevented. The burning temperature is related to the burning effect as well as the processing time, and if the processing time is about 3 to 10 minutes, it will be 180℃.
It can be carried out at a temperature of ~300°C.

(Example) Hereinafter, the present invention will be explained in more detail based on Examples.

Example 1 Aluminum alloys No. 1 to No. 1 with the composition shown in Table 1
12 was melted and cast, and both sides were faceted to a thickness of 350III1.
1. An ingot with a length of 2000 mm was prepared and soaked at a temperature of 560°C for 10 hours. This was heated and held at a temperature of 430°C for 1 hour, then hot rolled at a temperature of 430°C to 260°C to a plate thickness of 4.0m11, and then further plated to a thickness of 0.
The aluminum alloy plate for lithographic printing was produced by cold rolling to a thickness of 3 mm (area reduction rate: 92.5%).

Next, No. 1 to No. 12 aluminum alloy rolled plates and No. 13 (plate thickness 0.30 + am JIS1050-H
18 aluminum alloy), No. 14 (plate thickness 0-30m
The aluminum alloy (JISl100-H16 aluminum alloy) was grained using a rotating nylon brush in a suspension of hamstone and water, and then etched using a 20% aqueous solution of caustic soda so that the amount of aluminum dissolved was 5 g/rn'. After thoroughly washing with running water, the substrate was prepared by washing with water after pickling with a 25% nitric acid aqueous solution.

The cold-rolled plate obtained in this way has less than 0.012% of elemental Si present inside, and a uniform roughened surface can be obtained with a small amount of electricity in electrochemical roughening treatment, and during printing. It is suitable as a support for lithographic printing plates because it has excellent stain resistance in non-image areas, as well as excellent strength and printing durability.

The substrate prepared in this way was
According to the method described in Publication No. 3, the voltage at the anode was 10.4 V,
Using an asymmetrical sinusoidal alternating waveform current with a cathode surface voltage of 7.1 V, the anode special electricity quantity (Qa) and cathode electricity ff1 (Qc
) so that the ratio Q c / Q a is 0.45.
．． Electrolytic etching (electrochemical surface roughening treatment) was performed in a 7% nitric acid aqueous solution with various amounts of electricity input. Continuation 1
After cleaning the surface by immersing it in a 50°C aqueous solution of 5% sulfuric acid for 3 minutes, an oxide film of 3 g/rrf was formed in an electrolytic solution containing 20% sulfuric acid as a main component at a bath temperature of 30°C.

The following photosensitive layer was provided on the thus prepared sample at a coating amount of 2.5 g/rrr' during dry explosion.

Ester compound of naphthoquinone-1,2-diazido-5-sulfonyl chloride, pyrogallol, and acetone resin (as described in the Examples of U.S. Pat. No. 3,635,709) --1--0.75g cresol Novolauk resin - 2,00 g Oil Flu #603 (manufactured by Orient Chemical Co., Ltd.) - 04 g Ethylene cyclolito - 1-16 g 2-methoxyethyl acetate - 12 g Thus obtained Place the photosensitive lithographic printing plate in close contact with the transparent print and use the Ps light (Toshiba metal halide lamp MU2000-2-OL53K) from a distance of 1 m.
After exposure for 30 seconds with a V light source (light collected by Fuji Photo Film Co., Ltd.), the film was developed by immersing it in a 5% by weight sodium silicate aqueous solution for about 1 minute, washing with water,
Dried samples No. 1 to No.

14 was created.

Samples (printing plates) No. 1 to No. created in this way
, No. 14 was tested for the uniformity of the electrolytically etched rough surface, the stain resistance of the non-image area, and the tensile strength. The results are shown in Table 2.

(Test method) (1) Uniformity of the electrolytically etched rough surface The surface condition was observed using a scanning electronic WJ microscope, and the uniformity of pits was evaluated. Those with many defective etched areas are marked with △ and ×.

(2) Contamination in non-image areas After printing 100,000 copies using an offset printing machine KOR using a sample with an anode input electricity amount of 200 coulombs/dgo, the contamination in non-image areas was evaluated, and an excellent mark was given. , Good ones marked △,
Inferior items are indicated with an x mark.

(3) #Printing power After printing 10,000 copies in the same way as in (2), evaluate the sharpness of the printed matter: clear with no blurring (○), good (△), unclear (×) It was marked.

(4) Tensile Strength A JIS No. S tensile test piece was taken, and a tensile test was conducted to measure the strength.

The amount of elemental Si was quantitatively analyzed by the analysis method described in JP-A-60-82642.

As is clear from Table 2, all of the printing aluminum alloy plates No. 1 to No. 7 obtained by the method of the present invention have an internally distributed elemental Si content of 0.012% or less, which is higher than conventional JIS 1050. -HlB or 1100-HlB
It has better stain resistance and tensile strength in non-image areas.

Moreover, while JIS 1050-HlB requires an amount of electricity input at the time of anode of 200 coulombs/drn' to obtain a uniform rough surface, No.
1 to N007, a uniformly roughened surface can be obtained at 50 to 75 coulombs/drn', surface roughening can be performed by electrolytic etching with an input electricity amount of 100 to 100%, and printing durability is also good.

On the other hand, it can be seen that in No. 8, in which Sn was not added, the stain resistance of the non-image area was good, or a large amount of electricity was required to obtain a uniform rough surface. Furthermore, No. 9 to No. 12, in which the alloy composition is out of the range of the present invention, are poor in any of the stain resistance, tensile strength, rough surface uniformity, and printing durability of the non-image area.

Example 2 The alloy ingot of No. 2 in Table 1 in Example 1 was 55
A soaking process was carried out for 8 hours at a temperature of 0°C, and this was
After cooling under various cooling conditions shown in the table, hot rolling to a thickness of 4.5 mm, further cold rolling to a thickness of 2.0 mm, and then annealing in a continuous annealing furnace at a temperature of 480'C for 20 minutes. After intermediate annealing for a second, the aluminum alloy plate was cold rolled to a thickness of 0.3 mm to produce an aluminum alloy plate for printing plates.

These were subjected to surface treatment in the same manner as in Example 1, and plate making was performed under the same conditions to create Samples Nos. 15 to 24. The amount of electricity input at the time of anode was 75 coulombs/drn'.

The same test as in Example 1 was conducted on these samples,
The results are shown in Table 3.

As is clear from Table 3, after soaking the ingot, 43
Printing plates No. 15 to 19 according to the present invention were cooled at a temperature of 0° C. or less at an average cooling rate of 50° C./hour or less, and then hot-rolled, cold-rolled, intermediate annealed, and cool-rolled. It can be seen that the amount of elemental Si distributed in the area is 0.012% or less, and the uniformity of the rough surface and the stain resistance of the non-image area are excellent.

On the other hand, the amount of elemental Si distributed inside is 0.012%.
It can be seen that stains in non-image areas are not improved in comparative printing plate Nos. 20 to 24, that is, in aluminum alloy plates for printing plates in which the cooling conditions after soaking treatment are out of range.

Example 3 Using the alloy ingot of No. 12 in Table 1 in Example 1,
This was soaked at 540°C for 8 hours, held under the conditions shown in Table 4, hot rolled to a thickness of 3.5 mm, and then cold rolled to a thickness of 0.3 ms. did. This was subjected to surface treatment in the same manner as in Example 1, and samples No. 25 to 33 were obtained.
It was created.

The same tests as in Example 1 were conducted on these, and the results are shown in Table 4.

/''7/'/' As is clear from Table 4, after soaking treatment 350-450
Printing plate N according to the present invention kept at a temperature of 'C for more than 30 minutes
It can be seen that the amount of elemental Si in all samples 0 and 25 to 29 is 0.012% or less, which means that the uniformity of the rough surface and the stain resistance of the non-image area are excellent.

On the other hand, in comparison printing plates Nos. 30 to 33, which do not meet the ingot retention conditions after soaking, the amount of elemental Si distributed inside exceeds 0.012%, and stains in non-image areas are not improved.

(Effects of the Invention) As described above, the aluminum alloy support for lithographic printing plates of the present invention can obtain a uniform electrolytically roughened surface even with a small amount of electricity when performing surface roughening treatment, so it is energy-saving and cost-saving effective. It is large, has excellent printing durability, excellent stain resistance in non-image areas during printing, and is also excellent in strength, so it has all of these characteristics and is extremely effective as a support for lithographic printing plates. be.

Procedural amendment (c) 5 March 26, 1988 Commissioner of the Patent Office Kuro 1) Mr. Akio
71. Indication of the case 1985 Patent Application No. 282590 2. Name of the invention Aluminum alloy support for lithographic printing plates and its manufacturing method 3. Person making the amendment Relationship to the case Patent applicant address 2 Marunouchi, Chiyoda-ku, Tokyo Chome 6-1 Name: Furukawa Aluminum Industries Co., Ltd. Midoriya 2nd Building 7th floor; Date of amendment order: February 4, 1985 (shipped: February 24, 1988); Number of inventions increased by amendment: 0 , Target of amendment Insert "3. Detailed description of the invention" between lines 5 and 6 on page 2 of the description of the amendment, in the "Detailed description of the invention" column of the description.

Claims (2)

[Claims] (1) Fe0.05-0.5% by weight, Mg0.7-5% by weight, Sn0.01-0.2% by weight, Si0.2% by weight
An aluminum alloy support for a lithographic printing plate, characterized in that the following contains 0.05% by weight or less of Cu, the remainder consisting of Al and unavoidable impurities, and 0.012% by weight or less of elemental Si. (2) Fe0.05-0.5% by weight, Mg0.7-5% by weight, Sn0.01-0.2% by weight, Si0.2% by weight
Below, after soaking an aluminum alloy ingot consisting of Cu 0.05% by weight or less and the remainder Al and unavoidable impurities, 4
Cooling to a temperature of 30°C or less at an average cooling rate of 50°C/hour or less, or holding at a temperature of 350 to 450°C for 30 minutes or more, then hot rolling or after hot rolling, cold rolling and intermediate 1. A method for producing an aluminum alloy support for a lithographic printing plate, comprising annealing and final cold rolling with an area reduction of 50% or more to reduce elemental Si to 0.012% by weight or less.