JPS6126746A - Aluminum alloy for lithographic printing plate - Google Patents

Abstract

PURPOSE:To obtain an Al alloy for a lithographic printing plate having superior handleability and discriminating property of wettability by adding specified amounts of Fe, Si, Cu, Mn, Mg and Ti to Al and specifying the ratio of Si/Fe. CONSTITUTION:The composition of an Al alloy is composed of, by weight, 0.05-0.7% Fe, 0.01-0.3% Si, <=0.1% Cu, <=0.3% Mn, 0.5-1.5% Mg, 0.003-0.5% Ti and the balance Al with inevitable impurities, and the ratio of Si/Fe is regulated to <=1. The resulting Al alloy is cold rolled to 0.05-0.3mm. thickness, and the surface of the cold rolled plate having >=16kg/mm.<2> yield strength is electrolytically roughened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to an aluminum alloy for lithographic printing plates, and more particularly to an aluminum alloy for lithographic printing plates that has excellent handling properties and water wetness determination properties.

[Prior Art] Conventionally, Al050, A
1100, equivalent to A 3003 is used, and for the electrolytic surface roughening method, A]0 is used because of the ease of electrolytic surface roughening.
50 equivalent material is used. However, as the trend toward thinner walls has become stronger in recent years, thinner pure aluminum plates are more likely to cause problems such as bending, bending, and plate elongation during printing. In response to this problem, the present inventor developed a high-strength aluminum alloy for printing plates that could be subjected to electrolytic surface roughening treatment, and filed a patent application in 1708-1985.
The application has been completed as No. 03.

In this applied invention, high strength was sufficiently achieved, and there were few problems in terms of ease of handling of the plate, lifespan, etc., but due to the high strength, the content is The rough surface after electrolysis due to the ingredients becomes too fine and tends to have a gray appearance.Furthermore, this rough surface is anodized to improve the adhesion and water retention required for printing properties. It was found that this gray tendency was promoted when

Normally, lithographic printing plates are made by coating a roughened and anodized aluminum plate surface with photosensitive paint, removing the parts other than the necessary parts using an odo-etch process, and moistening the areas from which the photosensitive paint has been removed with water during printing. It is used as such. When a rough surface after anodizing is moistened with water, it becomes more gray due to the refractive index of light, and when it dries, the gray becomes weaker and whitish, so this is usually used to reduce the degree of water wetting. Judging.

Therefore, in order to determine water wetness, it is necessary to make the rough surface color tone after anodization white, and improvement in this point is desired in the above-mentioned high-strength materials.

[Problem to be Solved by the Invention 1] As a result of intensive research to investigate the causes of the problems in the prior art described above, the present inventor has found that the surface roughness that has been obtained up to now in the electrolytic surface roughening method -Contrary to the idea of color tone, we found that gray tones are stronger on extremely fine rough surfaces, and furthermore, even on electrolytically roughened surfaces and brush-polished rough surfaces that have a white tone, we found that the types and content of elements contained in In some cases, it has been discovered that due to the combination of defects generated during anodization and the rough surface of the base, a gray tone appears and the ability to determine water wetness is reduced.Based on these findings, the present inventor conducted further research, and as a result, They succeeded in developing an aluminum alloy for lithographic printing plates that has excellent water-wetting properties, high strength, and excellent handling properties.

[Means for solving the problems 1 The aluminum alloy for lithographic printing plates according to the present invention has (1)
Fe0.05-0.70wt%, Si 0.01~
0.30wt%, Cu≦0.1u+j%, Mn≦0.3
wt%, Mg0.5-1.5wt%, Ti 0.003
A first invention is an aluminum alloy for lithographic printing plates, which contains 0.05 wt%, S i / Fe ≦ 1.0, and the remainder consists of Al and unavoidable impurities, ) Fe 0.05-0.70wt%, Si 0
．． 01-0.30wt%, Cu≦0.1wt%, Mn≦
0.3IIIt%, Mg0.5-1,5+++t%, T
An aluminum alloy containing 0.003-0.05 wt% of i, Si/Fe≦1.0, and the balance consisting of Al and inevitable impurities, and characterized in that the ingot structure is a granular crystal structure. A second invention is an aluminum alloy for lithographic printing plates,
Furthermore, (3) Fe0.05-0.70wt%, Si0
．． 01-0.30wt%, Cu≦0.1wt%, MnS
2.3wt%, Mg 0.5-1.5%, Ti 0
．． 003~0.05wt%, Si/Fe≦1.0, and the balance is Al and unavoidable impurities, and the plate thickness after cold rolling is 0.05~0.30. The third invention is an aluminum alloy for lithographic printing plates, which has a yield strength of 16 kg/mm" or more at this plate thickness and is further subjected to electrolytic surface roughening treatment. It is.

In addition, on the surface of aluminum alloy for lithographic printing plates after electrolytic roughening, the number of peaks with a height of 0.2 μm or more is 60 to 1.
It is preferable to set it as 50/mm2.

The aluminum alloy for lithographic printing plates according to the present invention will be described in detail below.

First, the contained components and component ratios will be explained.

Fe is an element that is included to improve strength, refine recrystallized grains, and form crystallized substances to serve as an etching starting point during electrolytic surface roughening. If the content exceeds 0.70 wt%, the electrolytically rough surface becomes too fine and tends to exhibit a gray tone, and furthermore, even the brush polished rough surface tends to exhibit a gray tone after anodization. Therefore, the Fe content is 0.0
5-0.70wt%.

Si is an element that is included to adjust the etching start point during electrolytic surface roughening by forming Al-Fe-8i crystallized substances, and if the content is less than 0.01 wt%, the amount of Al-Fe compounds decreases. If the content exceeds 0.30 wt% and Si/Fe is 1.0 or more, AlF
There is solid solution Si that does not form e-3i type compounds, and unetched areas tend to appear during electrolytic roughening, and even if the surface is white during electrolytic roughening or brush polishing, it becomes grayish after anodizing. It becomes easier. Therefore, the Si content is 0
．． 01 to 0.30 wt%, and Si/Pe≦1.
Set to 0.

Cu is an effective element for improving strength and etching effect, and if the content exceeds 0.1 wt%, the electrolytically rough surface becomes too fine and tends to take on a gray color. Therefore,
The Cu content is 0.1 wt% or less.

Mn is an effective element for improving strength, handling, and adjusting the starting point of etching during electrolytic surface roughening.If the content exceeds 0.3 wt%, the electrolytically roughened surface becomes too fine and turns gray. It becomes easier to present. Therefore, the Mn content is 0.3
It should be less than wt%.

Mg is an important element for improving strength and stabilizing the electrolytically roughened surface.If the content is less than 0.5Illt%, this effect will be small, and if the content exceeds 1.5wt%, the electrolytically roughened surface will be During oxidation, the rough surface becomes too fine, resulting in a gray tone.
)easy. Therefore, the Mg content is set to 0.5 to 1.5%.

The inclusion of Ti for refining the ingot structure is necessary for uniform dispersion of crystallized materials, and the content must be 0,003 wt% or more, and the Ti content must not exceed 0.05 wt%. If this happens, the effect of i-clump refinement will be reduced, and any more content will be wasteful, and will tend to cause aggregation of Al--Ti particles, and will tend to form linear defects during surface roughening.

Therefore, the T1 content is set to 0.003 to 0.051%.

Note that a Ti-B alloy can also be used instead of Ti.

When casting a molten aluminum alloy having the above-described components and ratios, Mg0. It is desirable to remove Al-T1 particle (or Ti-8 particles when a Ti-B alloy is used) aggregates by filtering.

The obtained ingot is subjected to processes such as homogenization treatment, hot rolling, cold rolling, and intermediate annealing to obtain a plate thickness of 0.05 to 0.30 mm.

In ordinary Al050 equivalent materials, unetched areas tend to remain during electrolytic roughening depending on the manufacturing process, but with the rolled aluminum alloy plate for lithographic printing plates according to the present invention, such a phenomenon does not occur in normal industrial manufacturing processes. If the soaking conditions are within the range of 450 to 600'CXI to 48 hours, there will be fewer problems in the manufacturing process, and there will be less influence from intermediate annealing conditions, and cold open rolling will improve handling. Therefore, it is necessary to have a proof stress of 16 kg/mm2 or more.

[Example 1] Next, an example of an aluminum alloy for lithographic printing plates according to the present invention will be described.

Example 1 After filtering a molten aluminum alloy having the ingredients and proportions shown in Table 1 using a conventional method,
The ingot was formed into an ingot with a thickness of 00 to 600 mm. Note that only Comparative Example 7 does not use the ingot structure as a granular product structure.

These ingots are subjected to face milling, homogenization heating, hot rolling, cold opening rolling,
Intermediate annealing and cold rolling were performed to give a thickness of 0.24n+n+. Note that the finishing tempering was from H14 to H18.

These aluminum alloy plates were subjected to electrolytic roughening treatment or brush roughening treatment, and further anodic oxidation treatment, and their performance was evaluated.

(1) Electrolytic surface roughening treatment conditions Pre-treatment conditions 3% NaOH 150°C x 30sec-*Water washing → 30%)
(No, R, TX30sec→Water washing electrolysis condition 1.6%HNO3, 20℃ 60 A/dm2X 20sec, (50Hz AC)
Desmut 3% NaOH 150° C. x 30 sec→neutralization washing (2) Anodizing treatment conditions 15% H2SO4, 25° C. 6 A/dn+2X 40 sec Table 2 shows the color tone, shape of the electrolytically roughened surface, and overall evaluation at each stage.

As is clear from Table 2, the aluminum alloy for lithographic printing plates according to the present invention is superior to the comparative examples in all respects, and is also superior in overall evaluation.

Example 2 A molten aluminum alloy having the components and proportions shown in Table 3 was filtered according to a conventional method and then cast to a thickness of 500 mm. This ingot was soaked at 590°C for 4 hours in Comparative Example 2, and soaked at 540°C for 4 hours in other cases.
．． Hot rolled to a thickness of 5mm, then cold rolled to a thickness of 1mm, and then rolled at 360°C to a thickness of 1mm.
Annealing was performed for 2 hours, and cold rolling was further performed to a thickness of 0.20 mm.

This plate was evaluated for color tone and mechanical properties after electrolytic surface roughening treatment → anodization treatment, brush roughening treatment → anodic oxidation, and the results are shown in Table 4.

(1) Electrolytic surface roughening treatment Pretreatment conditions 3% NaOH, 50°C x 30 sec-* Neutralization and water washing.

Electrolyte quality 3% HCl + 0.2% H2So4.25°C.

100 A/dm2X 20 sec, 50 Hz AC.

Desmut 3% NaOH 150°C x 305ec-+neutralized water washing. 1
(2) Brush polishing (The principle diagram is shown in Figure 2.) Brush conditions Brush: 0.2m+nφ, 19 strands twisted, 30mm
length, made of nylon.

Brush roll: Outer diameter 320IIIIIIlφ.

・Brushing condition rotation speed 600 rpm Plate feeding (Al alloy plate) 30m/min reduction (+
), 3 mm (length when the Al alloy plate is rolled down by the brush roll 2 between the rubber rolls 2) Plate tension (F) 2 kg/mm2・Abrasive An abrasive mainly composed of SiO2 is mixed with water. The concentration is 30%.

・Post-processing 3% NaOH at 150°C for 30 seconds → Neutralization and washing with water.

(3) Anodizing treatment The same treatment as in Example 1 was performed.

Table 4 shows that the aluminum alloy for lithographic printing plates according to the present invention is significantly superior in terms of water wetness determination and strength compared to the comparative examples.

Example 3 An aluminum alloy having the components and proportions shown in Table 5 was melted by a normal method, and after casting, it was 0.19 m.
A mt plate was subjected to electrolytic surface roughening treatment, and then the surface roughness and color tone were evaluated.

The results are shown in Table 6.

As is clear from Table 6, the aluminum alloy for lithographic printing plates according to the present invention has a white color tone, excellent water wetness determination property, and strong potash coating adhesion, compared to the comparative example.
It can be seen that it is significantly superior overall.

Note that the electrolytic surface roughening treatment conditions are the same as in Example 1.

The number of ridges of 0.2 μm or more in rough surface evaluation was determined using a roughness meter at a vertical magnification of 10,000 and a horizontal magnification of 100.

Example 4 Aluminum and aluminum alloy molten metal having the components and component ratios shown in Table 7 were filtered according to a conventional method to form an ingot with a thickness of 400 mm. After heating this ingot under the soaking conditions shown in Table 8, 2.8m+nN
The specimens were hot rolled to a thickness of 0.7 mm, then heated under the intermediate annealing conditions shown in Table 8, and then cold rolled to a thickness of 0.1.5 mm.

As is clear from Table 8, the aluminum alloy for lithographic printing plates according to the present invention has a good electrolytically roughened surface shape even if the manufacturing process is quite different, whereas the comparative example has a good electrolytically roughened surface shape depending on the manufacturing process. This causes problems in terms of etching stability during electrolytic surface roughening treatment.

Note that the pretreatment conditions and desmut of the electrolytic surface roughening treatment conditions are the same as in Example 2.

Electrolytic conditions 1.6%HNO3, 25°C1 100A/dm2X 15sec, 50Hz AC.

[Effects of the Invention 1] As explained above, the aluminum alloy for lithographic printing plates according to the present invention has the above structure,
This is an aluminum alloy that has excellent surface roughening properties, handling properties, and water wetness determination properties for planographic printing plates.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the repeated bending test method, and FIG. 2 is an explanatory diagram of the brush polishing method.

Claims (4)

[Claims] (1) Fe0.05~0.70wt%, Si0.01~
0.30wt%, Cu≦0.1wt%, Mn≦0.3w
t%, Mg0.5-1.5wt%, Ti0.003-0
．． 1.05 wt% of Si/Fe≦1.0, and the remainder consists of Al and inevitable impurities. (2) Fe0.05~0.70wt%, Si0.01~
0.30wt%, Cu≦0.1wt%, Mn≦0.3w
t%, Mg0.5-1.5wt%, Ti0.003-0
．． An aluminum alloy for lithographic printing plates, which contains Si/Fe≦1.0, the balance being Al and unavoidable impurities, and the ingot structure is a granular crystal structure. (3) Fe0.05~0.70wt%, Si0.01~
0.30wt%, Cu≦0.1wt%, Mn≦0.3w
t%, Mg0.5-1.5wt%, Ti0.003-0
．． 05 wt%, Si/Fe≦1.0, and the balance is Al and unavoidable impurities, and the plate thickness after cold rolling is 0.05 to 0.30 m.
An aluminum alloy for lithographic printing plates, characterized in that it has a yield strength of 16 kg/mm^2 or more at this plate thickness, and is further subjected to electrolytic surface roughening treatment. (4) The lithographic printing plate according to claim 3, wherein the number of peaks with a height of 0.2 μm or more on the surface after electrolytic roughening is 60 to 150/mm^2. Aluminum alloy.