JPH09201649A - Production of aluminum alloy plate for planographic printing plate substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cast plate having uniform and fine cast structure and use the plate as an Al alloy plate for planographic printing plate substrate by specifying injection pressure of supplied molten metal at the tip part of a nozzle thereby supplying molten metal. SOLUTION: The molten Al alloy composed of <=0.8wt.% Fe, <=1.0wt.% S, <=0.2wt.% Cu and the balance Al with inevitable impurities is continuously cast into the cast plate having <=30mm thickness. Then the cast plate is cold- rolled and as necessary, is intermediate-annealed, and further is final-cold-rolled. In this case, the molten Al alloy is supplied into the space between movable molds 4, 5 from the horizontal direction, or while being tilted upward from the lower side to the horizontal direction or from just below side by the casting nozzle 2. The molten metal is supplied at >=0.6kPa injection pressure at the tip part of the nozzle 2.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an aluminum alloy plate for a lithographic printing plate support. More specifically, when the alloy plate is produced by a continuous casting and rolling method,
The present invention relates to a manufacturing method which enables use as an aluminum alloy plate for a lithographic printing plate support by improving the continuous casting conditions.

[0002]

2. Description of the Related Art Generally, as a method for producing an aluminum alloy sheet, a slab made by casting a molten aluminum alloy by a semi-continuous casting method is subjected to homogenizing heat treatment, and then hot rolling and cold rolling (annealing if necessary). Alternatively, the molten aluminum alloy is continuously supplied between the movable molds (the water-cooled drums 4 and 5 shown in FIG. 2 or the water-cooled belts 8 and 9 shown in FIG. 5) to obtain a cast plate having a plate thickness of 30 mm or less, which is then formed. Is cold-rolled (if necessary, may be annealed before, during, or afterwards) to obtain a plate material having desired size and performance, so-called continuous casting rolling method (hereinafter referred to as continuous casting rolling method)
Is common.

However, the aluminum alloy plate used for the lithographic printing plate support is formed into a plate by the above-mentioned process and then subjected to surface treatment such as chemical etching, electrochemical etching and anodic oxidation in the process of working as a lithographic printing plate. The homogeneity of the metallurgical structure of the material has a great influence on the surface quality. That is, if the metal structure varies, the appearance after the surface treatment becomes non-uniform in the form of strips or spots, which causes not only poor appearance but also poor printing due to uneven etching pits. Non-uniformity of the cast structure is one of the causes of the variation in the metal structure.

For example, the cast structure of the slab cast by the semi-continuous casting method generally changes its structure such as a chill layer, a coarse cell layer and a fine cell layer as it moves from the casting surface to the inside. Here, the combined portion of the chill layer and the coarse cell layer is generally called a frame and has an unstable metal structure, which adversely affects the surface quality. Therefore, it is generally scraped off by chamfering. The aluminum alloy sheet is manufactured by this method by subjecting the slab thus face-milled to homogenizing heat treatment and hot rolling, and then cold rolling (annealing if necessary) to obtain a predetermined sheet.

Further, the continuous casting and rolling method is a very effective method in which the homogenizing heat treatment of the ingot and the hot rolling step are omitted, and the yield and energy efficiency are improved, and the cooling rate of the molten metal is increased. Since the alloy components are easily forced to form a solid solution and the second phase particles are likely to become fine, an aluminum plate generally excellent in impact resistance, formability and fatigue strength can be obtained. It is said that an aluminum plate having a surface treatment such as an aluminum alloy support has an advantage that an aluminum plate having excellent gloss and corrosion resistance can be obtained (for example, JP-A-58-224136).

However, in this continuous casting and rolling method, since the mold moves continuously with respect to the molten metal supplied according to the basic principle of its manufacturing, the contact between the molten metal and the movable mold during casting is unstable. For this reason, there is a problem that the solidification rate of the molten metal tends to vary, which causes the cast structure to be non-uniform. A typical example of this is what is commonly called a "ripple mark" or "level line".
This is a defect that the casting structure is periodically changed at a pitch of several mm in the longitudinal direction of the cast coil, and this defect causes uneven surface treatment in the final product, resulting in poor appearance. Similar to the semi-continuous casting method, it is difficult to remove the non-uniform portion of the cast structure by chamfering because the plate thickness is thin at about 30 mm or less and it is usually difficult for this structure change even within the plate thickness of several mm. Since it affects the depth or even the central part of the plate thickness depending on the case, it is not a realistic method considering the yield.

As described above, the continuous casting and rolling method is more attractive than the semi-continuous casting method in terms of production efficiency and characteristics, but it is difficult to remove this portion due to nonuniform casting structure. For this reason, it has been generally said that it is not appropriate to apply it to the production of an aluminum plate, which is subjected to a surface treatment such as an aluminum alloy plate for a support for a lithographic printing plate and is required to have a uniform appearance after the treatment. It was a public opinion.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, specifically, a planographic plate subjected to surface treatment such as chemical etching, electrochemical etching and anodic oxidation. In the production of an aluminum alloy plate for a printing plate support by the continuous casting and rolling method, the casting conditions for obtaining a casting plate having a uniform and fine casting structure suitable for the production of this alloy plate were found. An object of the present invention is to provide a manufacturing method that can be used as an aluminum alloy plate.

[0009]

The present invention for solving the above-mentioned problems is a method for producing an aluminum alloy plate for a lithographic printing plate support by a continuous casting and rolling method, wherein Fe is 0.8 w.
t% or less, Si 1.0 wt% or less, Cu 0.2 wt
% Or less, with the balance being Al and unavoidable impurities, an aluminum alloy melt is continuously cast into a cast plate having a thickness of 30 mm or less, which is cold-rolled, intermediate-annealed, and finally cold-rolled. During continuous casting on the casting plate, the molten aluminum alloy is supplied between the movable molds by a casting nozzle between the movable molds, from the horizontal direction or inclined downward from above with respect to the horizontal direction, or from directly below, and the nozzle of the supplied molten metal. The method for producing an aluminum alloy plate for a lithographic printing plate support is characterized in that the jet pressure at the tip is supplied at 0.6 kPa or less. In the present invention, the supply of the molten aluminum alloy between the movable molds is more preferably inclined from the lower side to the upper side with respect to the horizontal direction or from directly below. Further, in the present invention, it is more desirable to supply the molten metal at a nozzle tip pressure of 0.4 kPa or less.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. First, among the constituent elements of the present invention, the Al alloy composition will be described. Fe in the alloy composition is 0.8 wt%
The range is as follows. It is preferably 0.5 wt% or less, more preferably 0.4 wt% or less. Fe has the function of making the electrolytically roughened surface uniform. Fe is an element that forms an Al-Fe-based and Al-Fe-Si-based intermetallic compound in combination with other elements in the aluminum alloy. Among these intermetallic compounds, the intermetallic compound of 1 to 20 μm is It has the effect of refining the crystal grains and the effect of forming a uniform and fine electrolytic rough surface. However, the reason for setting Fe in the above range is that when the content exceeds 0.8 wt%, it is 20 μm.
This is because the electrolytically roughened surface becomes non-uniform due to the formation of a coarse compound exceeding m.

Si is 1.0 wt% or less. It is preferably 0.5 wt% or less, more preferably 0.2 wt% or less. Si is usually contained as an impurity and is 1.0 wt%
If it exceeds the range, defects in which microscopically insufficient etching spots are scattered in the electrolytic roughening treatment, so-called unetched portions, tend to appear, which is not preferable. Therefore, Si is set in the above range.

Cu is 0.2 wt% or less. The reason why Cu is limited to 0.2 wt% or less is that when Cu exceeds 0.2 wt% as an impurity, the recesses (pits) generated by the electrochemical graining treatment are likely to become coarse, and the non-image as a printing plate is not formed. This is because the corrosion resistance of the part decreases. Preferably 0.15% wt or less, more preferably 0.1 wt
% Or less is good.

Other impurities include Mn, Cr, etc. contained in ordinary aluminum ingots, but if these are about 0.05 wt% or less, there is no particular problem. Further, as optional additional elements, each of Ti.
The content of 1 wt% or less is effective for refining the solidification structure during casting.

Next, manufacturing conditions after casting will be described. In casting the aluminum alloy in the present invention,
A continuous casting and rolling method is used in which a molten metal is directly cast into a cast plate having a thickness of 30 mm or less. The reason why the plate thickness is 30 mm or less is that, as described above, in the continuous casting and rolling method, the cooling rate of the molten metal can be increased, so that the alloy components are easily forced to form a solid solution, and the second phase particles However, it is easy to become fine, and thus various merits are obtained as a material property, but if the plate thickness exceeds 30 mm, a cooling rate sufficient for forced solid solution cannot be obtained, and the intermetallic compound becomes coarse, which is not preferable. Further, if it is too thick, the number of times of rolling in the lower step increases, which is not economical. Therefore, the thinner the thickness, the better, but preferably 15 mm or less, more preferably 1
0 mm or less is preferable.

The continuous casting in the continuous casting and rolling method which is the object of the present invention is carried out by the Hunter method using the twin drums 4 and 5 shown in FIG. 2, the 3C method, and the Hesley using the twin belts 8 and 9 shown in FIG. However, the present invention is not limited to these specific methods.

The continuous casting and rolling method of the present invention is shown in FIGS.
This will be described with reference to FIG. FIG. 1 is a plan view showing an example of manufacturing a continuous casting plate 6 with a movable mold device including twin drums 4 and 5. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, and is an explanatory view of supplying the molten metal from the horizontal direction to the movable molds 4 and 5 by the casting nozzle 2. FIG. 3 shows a twin drum 4,
FIG. 6 is an explanatory diagram of supplying the molten metal to the movable molds 4 and 5 with the casting nozzle 2 inclining from the lower side to the upper side with respect to the horizontal direction in the movable mold apparatus according to No. 5. FIG. 4 is an explanatory diagram of the movable mold apparatus including the twin drums 4 and 5, in which the molten metal is supplied to the movable molds 4 and 5 from directly below by the casting nozzle 2. FIG. 5 shows the rollers 10 to 10.
It is explanatory drawing which shows an example which manufactures the continuous casting plate 6 with the movable mold device by the twin belts 8 and 9 driven by 13.

First, an aluminum alloy melt 3 adjusted to a desired alloy composition is temporarily stored in a molten metal pool (usually called a head box etc.) 1 from a melting and holding furnace (not shown) through a trough, and then a casting nozzle 2 It is led to the movable molds (drums) 4 and 5 or the movable molds (belts) 8 and 9 which are water-cooled. In addition, 21 is a molten metal conduit of a nozzle, 22 is a tip of a nozzle, and 6 is a cast plate. There are the following two major purposes for temporarily collecting the molten metal in the pool 1. That is, the melt surface height of the pool 1 relative to the level of the casting nozzle tip 22 (hereinafter referred to as "molten head"; This is for adjusting the ejection pressure of the molten metal from the tip 22 of the casting nozzle.

In this regard, if the temperature of the molten metal in the puddle 1 is too high, sufficient solidification cannot be achieved until the molten metal comes into contact with the mold and desorbs, so that a perfect cast plate 6 cannot be obtained, and conversely. If the temperature is too low, the molten metal will solidify inside the casting nozzle before reaching the movable molds 4 and 5, and casting will be impossible. Therefore, it is desirable to maintain the temperature at an appropriate level. Usually, to make this temperature constant means to make the molten metal temperature at the tip 22 of the casting nozzle constant, and the molten metal 3 becomes
It must be set depending on the heat radiation condition etc. from reaching the casting nozzle tip 22 from
C., preferably 685 to 720.degree.

Further, in relation to the above, in the present invention, the molten metal jet pressure from the tip 22 of the casting nozzle 2 is 0.6 kPa.
The molten metal head 7 is adjusted so as to be as follows. In the continuous casting and rolling method, when the molten metal is supplied to the mold, when the molten metal is supplied to the mold from above, the molten metal 3 may be made to flow by a drop due to gravity, but the molten metal 3 which is the object of the present invention is supplied to the movable molds 4 and 5. In this case, the pressure for jetting the molten metal from the casting nozzle must be generated by supplying from the horizontal direction or inclined from the lower side to the upper side with respect to the horizontal direction or from just below. In the present invention, the molten metal 3 is supplied to the movable molds 4 and 5 not from above, but from the horizontal direction or inclined from below to above the horizontal direction or from directly below the molten metal injection pressure. Is easy to adjust. It is more preferable that the molten metal 3 is supplied to the movable molds 4 and 5 inclining from the lower side to the upper side with respect to the horizontal direction or from directly below for the above reason. Normally, this molten metal ejection pressure is adjusted by attaching the molten metal head 7 to promote the supply of molten metal. This molten metal ejection pressure is usually set high in order to avoid insufficient supply of the molten metal as long as the molten metal goes around the casting nozzle or does not damage the casting nozzle and other members. It was about 1 kPa.

In the present invention, however, a high molten metal ejection pressure is effective in preventing the molten metal supply shortage, but an excessively high pressure fluctuates the contact position between the movable molds 4 and 5 and the molten metal. It has been found that this is a reverse effect to obtain a uniform cast structure. When the ejection pressure is high, the tip 22 of the casting nozzle and the movable molds 4, 5
The molten metal is periodically swollen into the air gap, which changes the contact position between the movable mold and the molten metal to cause a change in the casting structure, which appears as a ripple mark. However, when the ejection pressure is low, the molten metal moves in accordance with the movement of the movable molds 4 and 5, so that the contact position between the movable mold and the molten metal is always kept constant, and as a result, a uniform casting structure in which ripple marks do not appear is formed. Become.

FIG. 6 shows the relationship between the molten metal ejection pressure at the tip 22 of the casting nozzle and the presence or absence of the appearance of ripple marks (uniformity of the casting structure) which led to the present invention. The molten Al alloy used was within the range of the present invention (Fe 0.3 wt.
%, Si 0.07 wt%, Cu 0.006 wt%, balance A
l). 7 (a) and 7 (b) are external photographs of these cast plates. (A) is a good product (ripple pressure 0.25 kPa) in which ripple marks do not appear, and (b) is
Indicates the appearance of ripple mark (melt spouting pressure 1.0
kPa). The arrow in the external appearance photograph (b) indicates the position where the ripple mark appears. For these reasons, in the present invention, the molten metal head 7 is lowered and the molten metal ejection pressure is made as small as possible. Specifically, the molten metal ejection pressure is 0.6k
It is desirable that the pressure is Pa or less, preferably 0.4 kPa or less.

Other casting conditions such as casting speed, mold cooling temperature, mold gap, etc. may be set in consideration of the desired product size, characteristics, facility capacity, etc., and are defined in the present invention. is not.

The cast plate 6 cast as described above may be rolled immediately after that if necessary, or may be wound around a coil as it is. After that, it is rolled to a desired size by cold rolling, but if necessary, before, in the middle,
After that, it is annealed once to several times to obtain a predetermined plate or strip. Further, performing alkali cleaning during the cold rolling is effective in removing oxide films and other surface foreign matters formed on the surface of the cast plate during continuous casting and rolling,
A more uniform rough surface can be obtained.

When the aluminum alloy plate for a lithographic printing plate support is used as a lithographic printing plate support, various surface treatments such as chemical etching, electrolytic etching and anodizing treatment are carried out. It is necessary that the appearance is uniform without occurrence of the above-mentioned ripple marks, streaks, etc., that a uniform rough surface is obtained, etc., and the aluminum alloy for a lithographic printing plate support according to the present invention produced as described above. The plate, as will be apparent from the examples described later,
It is excellent in the above-mentioned characteristics and can be sufficiently used as a lithographic printing plate support.

Next, the aluminum alloy plate for a lithographic printing plate support of the present invention is used as a lithographic printing plate support (PS plate, Pre-s).
Optimized Printing Plate)
Various surface treatment methods in the case of actually using the above will be described in detail. The plate surface is sharpened electrochemically in hydrochloric acid or nitric acid electrolyte, electrochemically sharpened with aluminum, the aluminum surface is scratched with a metal wire using the wire brush grain method, and the aluminum surface is sanded with abrasive balls and an abrasive. A mechanical graining method such as a ball graining method for graining or a brush graining method for graining the surface with a nylon brush and an abrasive can be used, and any of the above graining methods can be used alone or in combination. The aluminum alloy plate treated 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 industrially disadvantageous, but it can be improved by using an alkali as the etching agent.

Alkali agents preferably used include caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide and the like, and the preferable ranges of concentration and temperature are 1 to 50, respectively.
wt% is 20 to 100 ° C., and the amount of Al dissolved is 5 to 2
It is preferable that the condition be 0 g / m ² . After the etching, acid cleaning is performed to remove stains (smut) remaining on the surface. The acids used are nitric acid, sulfuric acid, phosphoric acid,
Chromic acid, hydrofluoric acid, and hydrofluoric acid are used. In particular, for the smut removal treatment after the electrochemical graining treatment, preferably 15 to 65 wt% of the temperature of 50 to 90 ° C. as described in JP-A-53-12739.
Of contacting with sulfuric acid of JP-A-48-28123
This is the method of alkali etching described in the publication.

The aluminum alloy plate treated as described above can be used as a support for a lithographic printing plate, but it is desirable to further subject it to anodizing treatment, caustic treatment and the like, if necessary. The anodizing treatment can be performed by a method conventionally performed in this field. Specifically, when a direct current or an alternating current is applied to aluminum in sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, etc., or an aqueous solution or a non-aqueous solution containing a combination of two or more thereof, the surface of the aluminum support It is possible to form an anodized film on. The conditions of anodic oxidation cannot be unconditionally determined because they vary depending on the electrolytic solution used, but generally the electrolytic solution concentration is 1 to 8
0 wt%, liquid temperature 5 to 70 ° C., current density 0.5 to 60 amperes / dm ² , voltage 1 to 100 V, electrolysis time 10 to 10
A range of 0 seconds is appropriate.

Among these anodic oxide film treatments,
A method of anodizing at high current densities in nitric acid used in the invention described in British Patent No. 1,412,768 and described in US Pat. No. 3,511,661. The method of anodic oxidation using phosphoric acid as an electrolytic bath is preferable. Anodized aluminum plates are further described in US Pat. Nos. 2,714,066 and 3,18.
Treatment with an alkali metal silicate such as those described in US Pat. No. 1,461, for example, by dipping in an aqueous solution of sodium silicate, or in US Pat. No. 3,860,
An undercoat layer of hydrophilic cellulose (eg, carboxymethylcellulose) containing a water-soluble metal salt (eg, zinc acetate) can also be provided, as described in US Pat.

A photosensitive layer conventionally known as a photosensitive layer can be provided on the lithographic printing plate support according to the present invention to obtain a photosensitive lithographic printing plate (PS plate). The lithographic printing plate thus obtained has excellent performance. The composition of the photosensitive layer includes the following. 1. Photosensitive layer comprising diazo resin system and binder US Pat. Nos. 2,063,631 and 1,667,
No. 415, which is a reaction product of a diazonium salt and an organic condensing agent having a reactive carbonyl group such as aldol and acetal, which is a condensation product of diphenylamine-p-diazonium salt and formaldehyde (so-called A photosensitive diazo resin) is preferably used. Other useful condensed diazo compounds are JP-B-48-4.
No. 8001 and No. 49-45322 are disclosed. These types of photosensitive diazo compounds are usually obtained in the form of water-soluble inorganic salts and can therefore be coated from aqueous solutions. Further, these water-soluble diazo compounds are reacted with an aromatic or fatty acid group compound having one or more phenolic hydroxyl groups, sulfonic acid groups or both by the method disclosed in JP-B-47-1167, It is also possible to use a substantially water-soluble photosensitive diazo resin which is a reaction product. In addition, JP-A-56-1
The diazo resin as described in 21031 is also preferable.

2. Photosensitive Layer Consisting of o-Quinonediazide Compound A particularly preferred o-quinonediazide compound is an o-naphthoquinonediazide compound, for example, US Pat.
No. 66,118, No. 2,767,092, No. 2,
772,972, 2,859,112, 2,907,665, 3,046,110, 3,046,111, 3,046,115,
No. 3,046,118, No. 3,046,119
No. 3,046,120 No. 3,046,12
No. 0, No. 3,046,121, No. 3,046,1
No. 22, No. 3,046,123, No. 3,061,
No. 430, No. 3,102,809, No. 3,10
No. 6,465, No. 3,635,709, No. 3,6
It is described in many publications including No. 47,443, and any of them can be preferably used.

3. Photosensitive layer comprising azide compound and binder (polymer compound) For example, British Patent Nos. 1,235,281 and 1,4
95,861, JP-A-51-32331 and JP-A-51
No. 36128, and a composition comprising an azide compound and a water-soluble or alkali-soluble polymer compound, as well as JP-A-50-5102 and 50-84302.
No. 50-84303, No. 53-12984, and a composition comprising a polymer containing an azide group and a polymer compound as a binder.

4. Other photosensitive resin layers For example, polyester compounds disclosed in JP-A-52-96696, British Patents 112,277, 1,313,309, 1,431,004, and Polyvinyl cinnamate resins described in No. 1,377,747 and the like, and photopolymerizable photopolymers described in US Pat. Nos. 4,072,528 and 4,072,527. A composition is included.

The amount of the photosensitive layer formed on the support is about 0.1 to 7 g / m ² , preferably 0.5 to 4 g / m ² .
It is in the range of m ² . After the PS plate is imagewise exposed, a resin image is formed by a process including a conventional development. For example, the photosensitive layer 1. comprising a diazo resin and a binder. In the case of the PS plate having the composition (1), the photosensitive layer in the unexposed portion is removed by development after image exposure to obtain a lithographic printing plate. Further, the photosensitive layer 2. In the case of the PS plate having the composition (1), the exposed portion is removed by developing with an aqueous alkali solution after image exposure to obtain a lithographic printing plate.

[0034]

【Example】

(Example 1) The molten aluminum alloy having the composition shown in Table 1 was used as an example of the present invention, a comparative example, and a conventional example as shown in FIGS.
A cast plate having a plate thickness of 7 mm and a cast plate having a thickness of 10 mm was obtained by the hunter method using the twin drum shown in FIG. Comparative example (N
o. As 16), a cast plate having a plate thickness of 35 mm was obtained by the Hesley method using a twin belt shown in FIG. In performing these castings, the molten metal ejection pressure from the tip 22 of the casting nozzle 2 is changed by adjusting the height of the molten metal head 7 in the molten metal pool (head box) 1, the present invention example and the comparative example, It is a conventional example. Here, the ejection pressure of the molten metal 3 is monitored by a pressure sensor set at the tip 22 of the nozzle tip, and it is also confirmed that this value is almost the same as the pressure calculated by the molten metal weight corresponding to the molten metal head 7. It was Also, the inclination of the casting nozzle 2 was changed variously.
These conditions are shown in Table 1. Casting conditions other than the above are as follows. -Plate width of cast plate: 1300 mm-Melting temperature: 700 ° C-Casting speed: 1000 mm / min. -Cooling rate: 300 to 700 ° C / sec. These cast plates 6 were cold-rolled and partially annealed under the conditions shown in Table 1 and then cold-rolled to 0.3 m.
m aluminum alloy plate was manufactured.

[0035]

[Table 1]

Next, these rolled aluminum alloy plates were grained with a rotating nylon brush in a suspension of pumice and water, and then a 20 wt% aqueous solution of caustic soda was used to dissolve aluminum to 5 g / m ^2. It was chemically etched. 25wt after thoroughly washing this with running water
% Nitric acid aqueous solution and then washed with water to prepare a substrate. The substrate prepared in this manner is disclosed in JP-A-54-146234.
As described in Japanese Patent Laid-Open Publication No. JP-A No. 2003-242242, electrolytic etching was performed in an electrolytic solution containing 1.5 wt% of nitric acid with an alternating current having a current density of 20 A / dm ² . Subsequently, the surface was washed by immersing it in a 50% aqueous solution of 15% sulfuric acid for 3 minutes, and then an anodic oxide coating of 3 g / m ² was provided at a bath temperature of 30 ° C. in an electrolytic solution containing 20 wt% of sulfuric acid as a main component. Regarding the aluminum alloy plate created as described above, the presence or absence of appearance of ripple marks after each of the above surface treatments, the uniformity of the appearance and the uniformity of the rough surface,
The evaluation was made as follows.

The evaluation method is as follows. (1) Presence or absence of appearance of ripple mark The surface condition after anodization was visually observed. (2) Uniformity of Appearance after Chemical Etching The appearance was judged to be excellent ⊚, good ∘, slightly inferior Δ, and inferior × when the appearance uniformity after etching with caustic soda was excellent. (3) Uniformity of electrolytically etched rough surface The surface condition was observed with a scanning electron microscope to evaluate the uniformity of the pits. Excellent ones are indicated by a circle, good ones by a triangle mark, and poor ones by a x mark. It was (4) Uniformity of appearance after anodizing treatment Excellent in uniformity of appearance after anodizing treatment ◎, good ○, slightly poor Δ, poor ×
The judgment was made as follows. (5) Occurrence of streak The surface condition after anodic oxidation is visually observed, and those with no streak defects are indicated by a circle, slight ones are indicated by a triangle, and marked ones are indicated by a cross. It was The test results are shown in Table 2.

[0038]

[Table 2]

As is clear from Table 2, the aluminum alloy plate produced under the conditions of the present invention has no surface defects,
It was also confirmed that it was excellent in uniformity of appearance and uniformity of rough surface, and that it could be used as an aluminum alloy plate for a lithographic printing plate support.

(Example 2) In order to perform a printing durability test, the sample No. 1 in Example 1 and Table 1 was used. The aluminum alloy plate of No. 2 was chemically etched, electrolytically etched, and anodized under the same conditions as in Example 1, and then the photosensitive layer having the following composition was applied at a coating amount of 2.5 g / m ² when dried. It was provided so that Ester compound of naphthoquinone-1,2-diazido-5-sulfonyl chloride with hirogalol and acetone resin (described in US Pat. No. 3,635,709) 0.75 g cresol novolac resin 2.00 g oil blue # 630 (Orient Chemical) 0.04 g Ethylene dichloride 16 g 2-Methoxyethyl acetate 12 g

The photosensitive lithographic printing plate thus obtained was brought into close contact with a transparent positive image and a PS light (having a light source of Toshiba Metal High Ride Lamp MU2000-2-0L type 3KW, from Fuji Photo Film Co., Ltd.) from a distance of 1 m. (Commercially available), exposed for 30 seconds, immersed in a 5% aqueous solution of sodium silicate for 1 minute for development, washed with water and dried to prepare a sample. When a 100,000-sheet printing test was conducted on this sample, it was confirmed that there was no problem in printing durability.

[0042]

As is clear from the above description, according to the present invention, an aluminum alloy plate for a lithographic printing plate support, which is subjected to surface treatment such as chemical etching, electrochemical etching and anodization, is subjected to continuous casting and rolling. Even if produced, a cast plate having a uniform and fine cast structure suitable for producing this alloy plate can be obtained, and it can be used as an aluminum alloy plate for a lithographic printing plate support. It has a remarkable effect.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of manufacturing a continuous casting plate with a movable mold device using twin drums.

FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1 and is an explanatory view of supplying molten metal from a horizontal direction to a movable mold by a casting nozzle.

FIG. 3 is an explanatory view of supplying molten metal to a movable mold with a casting nozzle inclining from the lower side to the upper side with respect to the horizontal direction.

FIG. 4 is an explanatory view of supplying molten metal from directly below to a movable mold by a casting nozzle.

FIG. 5 is an explanatory view showing an example of manufacturing a continuous casting plate by a movable mold device using a twin belt.

FIG. 6 is an explanatory diagram showing a relationship between a molten metal ejection pressure and the presence or absence of appearance of ripple marks (uniformity of casting structure).

FIG. 7 is a photograph showing the appearance of the surface of a cast plate, in which (a) is good and (b) is a ripple mark.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hot water pool (head box) 2 Casting nozzle 21 Molten metal conduit 22 Nozzle tip 3 Molten metal 4, 5 Drum (movable mold) 6 Casting plate 7 Melt head 8, 9 Belt (movable mold) 10-13 Roller

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[Procedure amendment]

[Submission date] May 22, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction contents]

FIG. 6 shows the relationship between the molten metal ejection pressure at the tip 22 of the casting nozzle and the presence / absence of ripple mark appearance (uniformity of the casting structure) which led to the present invention. The molten Al alloy used was within the range of the present invention (Fe 0.3 wt.
%, Si 0.07 wt%, Cu 0.006 wt%, balance A
l). 7 (a) and 7 (b) show the surface of these cast plates.
Microscopic study of Keller-etched metal surface texture
A mirror image is shown. (A) is a good one in which ripple mark does not appear (molten metal ejection pressure 0.25 kPa),
(B) shows the appearance of ripple marks (molten metal jet pressure 1.0 kPa). The arrow in the optical micrograph (b) indicates the position where the ripple mark appears. For these reasons, in the present invention, the molten metal head 7 is lowered and the molten metal ejection pressure is made as small as possible. Specifically, it is desirable that the molten metal ejection pressure be 0.6 kPa or less, preferably 0.4 kPa or less. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 22, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction contents]

FIG. 7 is an optical micrograph showing a metal surface structure of a cast plate .
In, (a) shows the favorable, (b) is obtained by the generation of the ripple marks.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction contents]

FIG. 7

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B41N 1/08 B41N 1/08 C22C 21/02 C22C 21/02 C22F 1/043 C22F 1/043 ( 72) Inventor Hidemitsu Matsumoto 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Hirokazu Sakaki 4000 Kawasakiri, Yoshida-cho, Harahara Group, Shizuoka Prefecture Fuji Shashin Film Co., Ltd. ( 72) Inventor Yoshinori Hotta 4,000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Fuji Shashin Film Co., Ltd.

Claims (1)

[Claims] 1. A method for producing an aluminum alloy plate for a lithographic printing plate support by a continuous casting and rolling method, wherein Fe is 0.8.
wt% or less, Si 1.0 wt% or less, Cu 0.2 w
An aluminum alloy melt containing t% or less and the balance of Al and unavoidable impurities is continuously cast into a cast plate having a thickness of 30 mm or less, which is cold-rolled, optionally annealed, and finally cooled. In the manufacturing method of hot rolling, during continuous casting into the casting plate, the molten aluminum alloy is cast between the movable molds by a casting nozzle, and is fed from below or above the horizontal direction or from below to the horizontal direction, or from below.
And, the jet pressure of the supplied molten metal at the nozzle tip is 0.6k.
A method for producing an aluminum alloy plate for a lithographic printing plate support, which is characterized by supplying Pa or less.