JPH0311635B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a support used in 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. The present invention relates to a support for a lithographic printing plate that can obtain a uniformly roughened surface by electrochemical surface roughening treatment and has excellent fatigue strength, thermal softening properties, and printability, and a method for producing the same. [Prior Art] Conventionally, planographic printing plates widely used are so-called aluminum plates that have been subjected to surface treatments such as roughening treatment and anodic oxidation coating, on which a photosensitive substance is applied and dried. Image exposure, phenomena,
This is a printing plate obtained by performing a plate-making process such as washing and lacquering. The undissolved photosensitive layer resulting from this development process forms an image area, and the area where the photosensitive layer is removed and the underlying aluminum surface is exposed is hydrophilic, so it becomes a water receiving area and does not form a non-image area. This is a well-known fact. Generally, aluminum plates are used as supports for lithographic printing plates, which are lightweight and have excellent surface treatment properties, workability, and corrosion resistance. pure
Al), JIS1100 (Al-0.05~0.20 wt% Cu alloy),
JIS3003 (Al-0.05~0.20wt%Cu-1.5wt%Mn
This is an aluminum alloy plate with a thickness of 0.1 to 0.8 mm, such as aluminum alloy), and the surface is roughened by one or a combination of mechanical, chemical, and electrochemical methods. The surface is roughened, and then preferably subjected to anodic oxidation treatment. Specifically, an aluminum lithographic printing plate subjected to mechanical roughening treatment, chemical etching treatment, and anodized film treatment described in JP-A-48-49501, or JP-A-51-61304. An aluminum lithographic printing plate that has been subjected to chemical etching treatment and anodized film treatment as described in the publication,
Aluminum lithographic printing plates subjected to electrochemical treatment, post-treatment, and anodic oxide film treatment described in JP-A-54-146234, electrochemical treatment described in JP-A-48-28123, Aluminum lithographic printing plates that have been subjected to chemical etching treatment and anodic oxidation film treatment, or aluminum lithographic printing plates that have been subjected to the treatment described in Japanese Patent Publication No. 48-28123 after mechanical roughening treatment are known. . By appropriately selecting the photosensitive layer coated on such a support, it is possible to obtain up to 100,000 sheets of clear printed matter. However, there is a desire to obtain more printed matter from one printing plate (improvement of printing durability).
In such cases, after exposing and developing the PS plate using an aluminum alloy plate as a support in the usual way,
An effective method is to strengthen the image area by heat treatment at high temperatures (so-called burning treatment).
This method is described in detail in Japanese Patent Publication No. 44-27243 and Japanese Patent Publication No. 44-27244. The heating temperature and time for such a burning process depend on the type of resin forming the image, but
The usual range was 3 to 7 minutes at a temperature of 200 to 280°C. [Problems to be Solved by the Invention] In recent years, there has been a desire for a burning treatment at a higher temperature and for a shorter time in order to improve printing durability and shorten the burning treatment time.
However, when the conventionally used aluminum alloy plates are heated to a high temperature of 280°C or higher, the aluminum recrystallizes, resulting in an extremely low strength and a loss of stiffness, making the plates extremely difficult to handle. This results in disadvantages such as the inability to set the plate on the printing machine and the inability to register the colors of the plate in multicolor printing, and therefore a stable aluminum alloy plate with high heat resistance is desired. On the other hand, today, as printing speeds have increased due to advances in printing technology, the stress applied to the printing plate, which is mechanically fixed to both ends of the plate cylinder of the printing press, has increased, so if the strength is insufficient, this fixed part may be It often becomes deformed or damaged, causing problems such as printing misalignment, or the plate breaks (grip breakage) due to repeated stress applied to the folded portion of the printing plate, making printing impossible. Conventional JIS1050 aluminum alloy plates can obtain uniform roughness and appropriate surface roughness through electrochemical roughening treatment, and stains in non-image areas during printing are less likely to occur, but fatigue resistance and heat softening resistance are inferior. . In addition, conventional JIS3003 aluminum alloy plates have sufficient fatigue strength and heat softening resistance, but electrochemical roughening treatment does not provide a uniform or appropriate surface roughness, and furthermore, during printing, A drawback was that non-image areas were easily smeared. The present inventor has developed an aluminum alloy plate for printing plates which can obtain a uniform rough surface by roughening treatment and has excellent fatigue strength, and a method for manufacturing the same, as described in Japanese Patent Application Laid-open No. 58-42745. developed, Mg0.05～
An aluminum alloy ingot consisting of 0.30% by weight, 0.03 to 0.30% by weight of Si, 0.15 to 0.40% by weight of Fe, and the balance being Al and normal impurities is soaked and hot rolled to give an area reduction of 70%. After applying the above cold rolling,
A method for manufacturing an aluminum alloy plate for printing plates was proposed, which is characterized by performing low-temperature annealing at a temperature of 150 to 250°C for one hour or more. However, in recent years, the quality required for printing plates has improved, and specifically, it is desired that non-image areas become less stained during printing, and further improvements in this respect are required. In order to prevent stains in non-image areas during printing, it is important to improve the water retention of non-image areas, and for this purpose roughening treatment,
In particular, it is necessary to obtain better uniformity of the roughened surface than in the past by electrochemical surface roughening treatment. [Means for Solving the Problems] Accordingly, the object of the present invention is to provide a printing plate with sufficient fatigue strength and heat softening resistance, and to provide a uniform roughness by surface roughening treatment, particularly electrochemical surface roughening treatment. It is an object of the present invention to provide a support for a lithographic printing plate, which has a suitable surface roughness and is less likely to cause stains in non-image areas during printing.
As a result of various studies regarding this, the present inventors found that
Mg0.05~0.3wt%, Si0.02~0.3wt%, Fe0.1~
0.4% by weight, less than 0.05% by weight of Cu, and the remainder consists of Al and normal impurities, and single Si distributed inside.
By setting the amount of 0.005% by weight or less,
It has been found that this product has the ability to achieve the above objectives. The above support has Mg0.05-0.3% by weight and Si0.02-0.3
After soaking an aluminum alloy ingot consisting of 0.1 to 0.4 wt% Fe, 0.05 wt% or less Cu, and the balance Al and normal impurities, the average cooling rate is 50°C/hour or less to a temperature of 430°C or less. After cooling at a high speed or holding at a temperature of 350-450℃ for more than 30 minutes,
Hot rolling or hot rolling followed by cold rolling and intermediate annealing, followed by final cold rolling with an area reduction of 70% or more, followed by tempering in a continuous annealing furnace at a temperature of 250 to 400°C for 120 seconds or less. Made by tempering. [Function] The reason why the composition of the support is limited as described above in the present invention is as follows. Mg is added for the purpose of improving the strength and thermal fatigue resistance without adversely affecting plate surface roughening treatment and printing suitability, and Mg is mostly dissolved in Al to improve strength and fatigue resistance. This is because if the content is less than 0.05% by weight (hereinafter, % by weight is simply referred to as %), the effect will be small, and if it exceeds 0.3%, the uniformity of the roughened surface in the surface roughening treatment will deteriorate. Fe is added to further improve fatigue strength, forming intermetallic compounds, refining crystal grains, and making the structure uniform, but if it is less than 0.1%, the effect is small, and if it is less than 0.4%
This is because if it exceeds this, the uniformity of the rough surface in the roughening treatment and the printability will deteriorate. Si 0.02~0.3%
The reason for this limitation is that if it is less than 0.02%, the strength will decrease, and if it exceeds 0.3%, the uniformity of the roughened surface after electrochemical roughening will deteriorate and elemental Si will be likely to precipitate. 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 was reduced to 0.005%.
The reason for limiting the amount of elemental Si to the following is that elemental Si remains in the anodic oxide film due to anodizing treatment and becomes the starting point for staining in non-image areas during printing, so the amount of elemental Si present is restricted to 0.005% or less. By doing so, it is possible to obtain a printing plate that is less likely to be smudged in non-image areas and has extremely excellent printability. Impurities contained in the aluminum alloy constituting the lithographic printing plate support in the present invention include:
The purpose of the present invention will not be impaired if the impurities are contained in Al ingots that are usually commercially available. That is, there is no particular problem if Mn is 0.05% or less, Cr is 0.05% or less, and Zn is 0.05% or less. In addition, when manufacturing ingots, Ti and B, which are usually used as crystal refining agents, contain less than 0.03% of Ti and 0.01% of B.
The following additions are 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 soaking treatment to dissolve Mg and impurities in solid solution, as well as a part of Fe. The intermetallic compounds are uniformly and finely dispersed. This soaking treatment is preferably carried out at a temperature of 500 to 620°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
Alternatively, 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 an Al-Fe-Si intermetallic compound, and then used as a single substance in the subsequent process.
Reduces the amount of Si precipitation. Thereafter, hot rolling is carried out in a conventional manner, or cold rolling and intermediate annealing are performed after hot rolling. It is appropriate to carry out hot rolling at a temperature of 450 to 200°C, and if necessary, intermediate annealing after hot rolling is performed at 300 to 450°C for 2 to 5 hours or in a continuous annealing furnace at 400 to 550°C for 120 hours. It is desirable to do this in less than a second. The plate thus obtained is finally cold rolled so that the reduction in area is 70% or more. In this final cold rolling, intermetallic compounds are dispersed and the crystal structure becomes uniform. If the area reduction rate is less than 70%, 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 thus obtained rolled plate is rapidly annealed in a continuous annealing furnace at a temperature of 250 to 400°C, preferably 270 to 350°C for 120 seconds or less. Temper annealing under these conditions gives the rolled plate appropriate mechanical properties.
In other words, by providing appropriate strength and elongation and improving heat softening resistance, and at the same time suppressing the precipitation of elemental Si as much as possible, a uniform pit shape and appropriate surface roughness can be obtained by roughening the surface. This is to improve water retention and stain resistance of non-image areas during printing. If the so-called quality annealing conditions are lower than 250℃ or higher than 400℃, or if the treatment time exceeds 120 seconds, sufficient fatigue resistance and heat softening resistance will not be obtained, and pits will occur due to surface roughening due to precipitation of elemental Si. The shape also becomes non-uniform, and the water retention and stain resistance of non-image areas decrease. The support for the lithographic printing plate of the present invention produced in this way has a more uniform pit shape and appropriate surface roughness than JIS1050 aluminum alloy due to the surface roughening treatment, and has good water retention and stain resistance in non-image areas. In addition to improved properties, products with excellent fatigue resistance and heat softening resistance can be obtained. 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 that electrochemically grains the grain in a hydrochloric acid or nitric acid electrolyte, a wire brush graining method that scratches the aluminum surface with a metal wire, and an abrasive ball and abrasive agent that polishes the aluminum surface. Mechanical graining methods such as the ball grain method, which sands the surface, and the brush grain method, which sands 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 a very long time to destroy the microstructure, which is disadvantageous when applying the present invention industrially, but this can be improved by using an alkali as an etching agent. . The alkaline agents preferably used in the present invention include 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% for each. , 20~100℃
Conditions are preferable such that the amount of Al dissolved is 5 to 20 g/m ² . 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 hydrofluoric 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 current or alternating current is passed through aluminum in an aqueous or non-aqueous solution such as sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sumiphalic acid, benzenesulfonic acid, etc. or a combination of two or more of these, aluminum supports. 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 anodized aluminum plate 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 US Pat. No. 3,860,426, a subbing layer of hydrophilic cellulose (such as carboxymethylcellulose) containing a water-soluble metal salt (such as zinc acetate) 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 composition of the photosensitive layer includes 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 condensable compound of the product 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 and Japanese Patent Publication No. 49-49.
-45322, 49-45323, etc. These types of photosensitive diaso 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 aliphatic 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 tetrafluoroborate 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. Binder of azide compound (photosensitive layer made of a polymer compound) For example, the specifications of British Patent No. 1235281 and British Patent No. 1495861, and Japanese Patent Application Laid-Open No. 1983-32331, British Patent No.
In addition to the composition comprising an azide compound and an aqueous solution or an alkali-soluble polymer compound described in Japanese Patent Application Laid-open 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 0.1
to about 7 g/m ² , preferably from 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 phenomenon 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. After the development treatment, the printing plate is subjected to appropriate post-treatment as desired. In post-processing, the most relevant process is burning for enhancement of image parts. Regarding burning, for example, JP-A No. 52-6205,
JP 51-34001, JP 55-28062, JP 57-3938, and U.S. Patent No. 4191570
Although it is described in the specification of the issue, basically, burning is a process in which a developed printing plate is placed in an atmosphere with a temperature of 150 to 350°C, and the image part of the plate is sintered.
It is to harden. In this case, it is preferable to supply the print with an aqueous solution of, for example, boric acid, a borate salt, an anionic surfactant, or another compound having a specific chemical structure, before or after burning. Thereby, various harmful effects caused by burning can be prevented. The burning temperature is related to the burning effect along with the processing time, and the processing time is 3~
It can be carried out at a temperature of 180 to 300°C for about 10 minutes. The present invention will be explained in more detail with reference to Examples below. Note that % indicates weight % unless otherwise specified. 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 pressure of 350 mm and a length of 2000 mm, which was soaked at a temperature of 560°C for 10 hours. This was heat treated at a temperature of 420℃ for 3 hours, then hot rolled at a temperature of 420 to 250℃ to a thickness of 4.5mm, and then further thick-rolled to a thickness of 0.3mm (area reduction rate of 93.3%). did. These were continuously passed through an annealing furnace and subjected to temper annealing at 300°C for 30 seconds to produce an aluminum alloy plate for lithographic printing plates. Next, No. 1 to No. 12 aluminum alloy rolled plates and
No. 13 (plate thickness 0.30mm JIS1050-H18 aluminum alloy), No. 14 (plate thickness 0.30mm JIS1100-H16 aluminum alloy), No. 15 (plate thickness 0.30mm JIS3003-H14 aluminum alloy) in a suspension of pumice stone and water. After graining with a rotating nylon brush, 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 was carried out with a 25% nitric acid aqueous solution, and the substrate was prepared by washing with water. The substrate prepared in this way was processed as described in Japanese Patent Application Laid-open No. 146234/1983.
Current density 20A/in an electrolytic bath containing 0.5-2.5% nitric acid
AC electrolysis was carried out at dm ² or more. Continued with 15% sulfuric acid
After cleaning the surface by immersing it in a 50℃ aqueous solution for 3 minutes, it was placed in an electrolytic solution containing 20% sulfuric acid as a main component at a bath temperature of 30℃.
An oxide film of 3 g/m ² was provided. The following photosensitive layer 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) Cresol novolak resin 2.00 g 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 and exposed to a PS light [equipped with a Toshiba metal halide lamp MU2000-2-OL type 3KW light source] from a distance of 1m. After exposure for 30 seconds with a 5% sodium silicate aqueous solution (sold by Fuji Photo Film Co., Ltd.), the samples were developed by immersing them in a 5% sodium silicate aqueous solution for about 1 minute, washed with water, and dried. Created 15. Tests were conducted on the uniformity of the electrolytically etched rough surfaces, stains in non-image areas, fatigue strength, and thermal softening properties of Samples No. 1 to No. 15 prepared in this way, and 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) Dirt in non-image areas The stains in non-image areas were evaluated using the offset printing machine KOR, and those with particularly excellent marks are ◎, and those with excellent marks are ○.
Good results are indicated by △ marks, and poor results are indicated by × marks. (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) Thermal Softening Properties The sample was heated at 300° C. for 7 minutes in a Burnig Processor 1300 [Burnig Processor manufactured by Fuji Photo Film Co., Ltd. with a 12 KW heat source]. After cooling, a JIS No. 5 test piece was created and subjected to a tensile test.
The 0.2% proof stress value was measured. The amount of elemental Si was quantitatively analyzed using the analysis method described in the Analytical Chemistry Handbook.

[Table] Plate board

JIS1100−H16 14 0.01 0.13 0.53
0.12 〃 〃 0.025 ×
JIS3003−H14 15 0.00 0.24 0.59
0.13 0.99 〃 0.038 ×

[Table] Plate board

JIS1100−H16 14 ×
230 190 15.2 7.0
JIS3003−H14 15 ×
680 490 14.8 13.5
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 all have a uniformity of the electrolytically etched rough surface depending on the amount of elemental Si distributed inside them at 0.005%. , satisfies all characteristics in terms of stain resistance of non-image areas during printing, fatigue resistance strength, and heat softening resistance, and exceeds conventional JIS1050,
It can be seen that it is superior to 1100 and 3003.
On the other hand, in 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, the amount of elemental Si distributed inside was
It can be seen that even if the content is 0.005% or less, the uniformity of the rough surface, staining of non-image areas during printing, fatigue strength, and heat softening resistance are poor. That is, 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 fatigue strength and heat resistance, and No. 9, which has a high Mg, Si, and Fe content. No. 11 had good fatigue strength and heat resistance, but was poor in the uniformity of the rough surface and in the staining of non-image areas during printing. Also contains a lot of Cu
No. 12 had 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 600°C for 8 hours,
It was then cooled to a temperature of 410°C at an average cooling rate of 20°C/hour. This was hot rolled at 400 to 300°C to a thickness of 3.0 to 8.5 mm, then cold rolled under various conditions shown in Table 2 (○ marks in the table indicate intermediate annealing), followed by temper annealing and printing. An aluminum alloy plate for plates was manufactured. 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 27. For comparison, a plate was made using the conventional JIS1050 (component No. 13 in Table 1) under the conditions shown in Table 2, and plate making was performed in the same manner as above to prepare sample No. 28. These samples were subjected to the same tests as in Example 1, and the results are shown in Table 2.

【table】

[Table] As is clear from Table 2, after hot working, the area reduction rate is 70
% or more, and then tempered in a continuous annealing furnace at a temperature of 250 to 400°C for 120 seconds or less so that the amount of elemental Si is 0.005% or less. Printing plates No. 16 to No. 21 were manufactured under conventional temper annealing conditions (annealing in a batch furnace) in terms of rough surface uniformity, non-image areas and stains during printing (No. 26, No. 21). 27) and the JIS1050 printing plate (No. 28), which has a conventional composition and was manufactured under conventional temper annealing conditions, and has a fatigue strength of more than 60,000 cycles, and also has excellent thermal softening after burning at 300℃ for 7 minutes. Looking at the characteristics, all had a yield strength of 12 kg/mm ² or more. Note that No. 16 to No. 19 are cases without intermediate annealing.
No. 20 and No. 21 are cases in which intermediate annealing was applied, and the results were good in both cases. On the other hand, in No. 22, which has a low area reduction rate, the amount of elemental Si distributed inside exceeds 0.005%, and although the fatigue strength and heat resistance are good, the uniformity of the rough surface and the staining of non-image areas during printing are poor. In No. 23 to No. 25, in which the temperature and time of the temper annealing conditions are outside the range of the present invention, the amount of elemental Si distributed inside exceeds 0.005%, causing problems with the uniformity of the rough surface and during printing. The stains in the non-image area are caused by the conventional printing plate.
Equivalent to JIS1050, but inferior in both fatigue strength and heat resistance. Example 3 The public gold ingot No. 2 in Table 1 in Example 1 was
After soaking at a temperature of 550°C for 8 hours and cooling under various cooling conditions shown in Table 3, hot rolling to a plate thickness of 4.5 mm, and further cold rolling to a plate thickness of 3.0 mm. , 20 at a temperature of 480℃ by continuous annealing furnace
It was intermediately annealed for seconds and then cold rolled to a thickness of 0.3 cm. This was subjected to final annealing at a temperature of 300° C. for 15 seconds in a continuous annealing furnace to produce an aluminum alloy plate for printing plates. These were subjected to surface treatment in the same manner as in Example 1,
Plate making was performed under the same conditions to create samples Nos. 29 to 40. For comparison, the conventional JIS1050 (No.13 in Table 1)
A plate was also made under the conditions shown in Table 3 for (components), and plate making was performed in the same manner as above to prepare sample No. 41. The same tests as in Example 1 were conducted on these samples, and the results are shown in Table 3.

[Table] As is clear from Table 3, 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,
Printing plates No. 29 to 35 according to the present invention, which were subjected to intermediate annealing, cold rolling, and continuous annealing, had a large amount of elemental Si distributed inside.
It can be seen that at 0.005% or less, the uniformity of the rough surface, staining of the image area, and fatigue strength are excellent. In contrast, the amount of elemental Si distributed inside is 0.005
It can be seen that stains in the image area are not improved in comparative printing formats No. 36 to 40, in which the cooling conditions after the soaking treatment are outside the range. Example 4 Using the alloy ingot of No. 2 in Table 1 in Example 1, it was soaked, held under the conditions shown in Table 4, hot rolled, and then prepared in Example 3.
In the same manner as above, the plate thickness was 0.3 mm, and the final annealing (300℃・15
2), and surface treated in the same manner as in Example 1 to prepare samples Nos. 42 to 50. For comparison, the conventional JIS1050 (component No. 13 in Table 1) is also
A plate was made under the conditions shown in the table and plate-making was performed in the same manner to prepare sample No. 51. The same tests as in Example 1 were conducted on these, and the results are shown in Table 4.

[Table] As is clear from Table 4, after soaking treatment 350 ~
All of the printing plates No. 42 to 46 according to the present invention, which were held at a temperature of 450°C for 30 minutes or more, had an elemental Si content of 0.005% or less,
It can be seen that the uniformity of the rough surface, the staining of non-image areas, and the fatigue strength are excellent. On the other hand, in comparative printing plates Nos. 47 to 50, in which the ingot retention conditions after the soaking treatment were not met, the amount of elemental Si distributed inside exceeded 0.005%, indicating that stains in non-image areas were not improved. In this way, the lithographic printing plate support of the present invention is different from the conventional one.
A lithographic printing plate that has excellent rough surface uniformity equivalent to or better than 1050 aluminum plate, and is resistant to staining of non-image areas of printed matter and has sufficient fatigue strength and heat softening properties. It has a remarkable effect.

Claims (1)

[Claims] 1 Mg0.05-0.3% by weight, Si0.02-0.3% by weight,
A lithographic printing plate support comprising 0.1 to 0.4% by weight of Fe, 0.05% by weight or less of Cu, the balance Al and normal impurities, and the amount of elemental Si distributed inside is 0.005% by weight or less. body. 2 Mg0.05-0.3% by weight, Si0.02-0.3% by weight,
After soaking an aluminum alloy ingot consisting of 0.1 to 0.4% Fe, 0.05% Cu or less, and the balance Al and normal impurities, it is cooled to a temperature of 430℃ or less at an average cooling rate of 50℃/hour or less. or 350-450℃
After holding at the temperature of 1. A method for producing a support for a lithographic printing plate, characterized in that the amount of elemental Si distributed inside is reduced to 0.005% by weight or less by thermal annealing at a temperature of ~400°C for 120 seconds or less.