JPH0368939B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an aluminum alloy base plate used as a support for offset printing or a support for lithographic printing (hereinafter referred to as an aluminum alloy base plate for printing). Conventionally, aluminum alloy base plates for printing have generally been JIS standard A1050P with a plate thickness of approximately 0.1 to 0.5 mm.
Rolled plates such as A1100P or A3003P were used. These printing blanks are usually produced by removing the surface of the ingot obtained by semi-continuous casting by face milling, applying homogenization treatment as necessary, and then heating it to a predetermined temperature to heat it. Rolled and then cold-rolled at a working rate of 20 to 95% to obtain an intermediate thickness, or directly cast a coil with a thickness of 12 mm or less by continuous casting without going through the hot rolling process. Cold rolled to an intermediate thickness, then intermediate annealed to the intermediate thickness plate, followed by final cold rolling at a reduction rate of 20-95% to obtain the required mechanical properties. It is manufactured by When actually using such a printing aluminum alloy base plate for printing, the surface of the base plate is first processed by one or more of mechanical, chemical, and electrochemical methods, or by a combination of two or more methods. After the surface is roughened by the process described above, it is preferably subjected to an anodizing treatment, then a photosensitive agent is applied and exposed, and plate making processing such as development is performed, and then the strength of the photosensitive film is improved to improve printing durability. Heat treatment at 250-300℃ for a short time (this is called burning treatment)
The ink is then wrapped around the cylindrical plate cylinder of a printing press, the ink is deposited on the image area in the presence of dampening water, and the ink is transferred to a rubber blanket and printed on the paper surface. The printing aluminum alloy base plate used as described above is required to have the following properties (A), (B), and (C). (A) It is possible to form unevenness uniformly through surface roughening treatment, there is no unevenness after surface roughening, and the surface has an appropriate color tone. The ability to roughen the surface uniformly and appropriately in this manner is hereinafter referred to as "surface treatability." (B) There is little decrease in strength due to burning treatment. Hereinafter, such performance will be referred to as "burning property". (C) No ink stains will occur in non-image areas during printing. This is hereinafter referred to as "ink stain resistance." Among these characteristics, if the surface treatment properties of (A) are poor, the color tone after roughening may become whitish or too dark, and in some cases, color unevenness may occur. Product value decreases. In addition, since the unevenness after roughening has a great effect on printing durability and image clarity, it is fundamentally important for printing plates to have good surface treatment properties and uniform unevenness after roughening. It is a condition. When the surface roughening treatment is carried out by electrolytic etching, it is natural that the condition of the roughened surface changes variously depending on the electrolytic conditions and the type of etching solution, but the phenomenon is caused by the electrochemical interaction between the aluminum surface and the electrolytic solution. Since it is a reaction, it goes without saying that the contribution of the material itself and its properties (surface treatment properties) cannot be ignored.
However, in conventional printing aluminum alloy base plates, the surface treatment properties for roughening have not been deeply studied, and the reality is that they cannot necessarily be said to have sufficient surface treatment properties. On the other hand, regarding the burning property of (B), a PS plate with an aluminum alloy plate as a support was exposed in the usual way.
It is reported in Japanese Patent Publication No. 44-27243 that it is effective to strengthen the image area by heat treatment at high temperature (so-called burning treatment) after development.
It is described in detail in Special Publication No. 44-27244,
The heating temperature and time of this burning process depend on the type of resin forming the image, but
A temperature range of 200 to 280°C for 3 to 7 minutes is customary. However, in recent years, it has become desirable to perform the burning process at a higher temperature in order to improve printing durability and shorten the burning process time. However, when the conventionally used aluminum alloy plate is heated to a high temperature of 280°C or higher, a recrystallization phenomenon occurs, resulting in an extremely low strength and loss of stiffness, making it extremely difficult to handle the plate. There are disadvantages such as the inability to set the plate on the machine and the inability to register the colors of the plate in multicolor printing. Therefore, there is a strong desire to develop an aluminum alloy plate with high heat resistance that can withstand burning treatment at high temperatures, that is, an aluminum alloy base plate for printing with excellent burning properties. Furthermore, regarding (C) ink staining, printing plates must basically avoid ink from adhering to non-image areas during printing and staining the printed matter. According to research conducted by the present inventors, it has been found that the main cause of this ink stain during printing is localized corrosion caused by the reaction of the printing plate with dampening water. This invention was made against the background of the above-mentioned circumstances, and has the above-mentioned three characteristics, namely, surface treatability,
The object of the present invention is to provide an aluminum alloy base plate for printing that is excellent in all aspects of burning property and ink staining property. In order to achieve the above-mentioned purpose, the present inventors conducted extensive experiments and studies on the chemical composition of aluminum alloy blanks that affect the above-mentioned properties and the intermediate annealing conditions during the blank manufacturing process, and found that the surface treatment The Si layer, Cu content, and Mg content in the material affect the
The inventors discovered that the amount of Si in the material and the intermediate annealing temperature have a strong influence on the burning property, and the amount of Si has a strong influence on the ink staining property, leading to the creation of this invention. In other words, first of all, regarding surface treatment properties, the higher the amount of Si in the material, the more uniformly rough the surface can be obtained.
It is influenced by the difference between the Si content and the Mg content, that is, the (Cu−Mg) content, and the higher the (Cu−Mg) content, the lower the Si
It has been found that the range in which a good rough surface can be obtained is expanded depending on the amount. On the other hand, regarding burnability, it was found that the lower the amount of Si in the material and the higher the intermediate annealing temperature, the less the decrease in strength after burning treatment. Furthermore, regarding ink stain resistance, it was found that the smaller the amount of Si in the material, the better the ink stain resistance. And from these findings,
In the condition range of (Cu-Mg)≧0, there is a Si amount range that simultaneously satisfies the three properties of surface treatment properties, burning properties, and ink stain resistance (however, the Si amount range depending on the Cu-Mg amount and intermediate annealing temperature). discovered that it exists and completed this invention. Specifically, the printing aluminum alloy base plate of the present invention is heated to an aluminum alloy material of 300 to 550°C.
A rolled plate obtained by cold rolling at a processing rate of 20 to 95% after intermediate annealing for 24 hours or less, with an alloy composition of Si 0.08% or less, Fe 0.05 to 1.0%, Cu 0.03%. Below, Ti is 0.10% or less, Mg is 0.03% or less as impurities, and the remainder is unavoidable impurities and Al.
Si amount (Si%), Cu amount (Cu%), Mg amount (Mg%)
And depending on the intermediate annealing temperature T (℃), the following (1),
The surface treatment property, the burning property, and the ink stain resistance are within the range that satisfies the formula (2), and the difference between the Cu content and the Mg content is within the range that satisfies the following formula (3). This is an aluminum alloy base plate for printing with excellent three properties. (Si%)≧0.08−4 {(Cu%)−(Mg%)} ……(1) (Si%≦2T/625−1.28 ……(2) 0≦{(Cu%)−(Mg%) }≦0.03 ...(3) Further, the aluminum alloy base plate for printing of the present invention will be explained in detail. First, regarding surface treatment properties, as mentioned above, the higher the amount of Si in the material, the more difficult it will be after roughening treatment. The unevenness of the surface becomes uniform, and the amount of Si for this purpose is influenced by the difference between the amount of Cu and the amount of Mg, that is, the amount of (Cu−Mg),
The larger the amount of (Cu-Mg), the more uniform the unevenness can be obtained even when the amount of Si is lower. As a result of detailed experiments by the present inventors, in order to obtain excellent surface treatment properties, the amount of Si in the material must be adjusted according to the amount of (Cu-Mg).
It has been found that it is necessary to satisfy equation (1). The range of Si content and the range of intermediate annealing temperature T in equation (1) are shown using the case where the (Cu-Mg) content is 0.01% as an example. becomes. In the region below this straight line AB, the unevenness of the roughened surface after the roughening treatment becomes irregular, making it impossible to form a uniform roughened surface. Note that the position of this straight line AB changes depending on the amount of (Cu−Mg) according to equation (1), and especially as the amount of (Cu−Mg) increases, the position of the straight line AB changes.
AB goes down. Next, the amount of Si and the intermediate annealing temperature are related to the burning property, and the lower the amount of Si and the higher the intermediate annealing temperature, the less the decrease in strength after the burning process. According to detailed experiments by the present inventors, when the amount of Si satisfies the range of equation (2) above in relation to the intermediate annealing temperature T (°C), the strength decrease after the burning process can be effectively reduced. It has been found that this can be suppressed to an extent that causes no problems. If the range of this equation (2) is illustrated, it is the area to the right of the straight line CD in FIG. In the region to the left of this straight line CD, the strength decreases significantly after the burning treatment, and for example, after the burning treatment at 270° C. for 7 minutes, the 0.2% yield strength becomes 5 Kg/mm ² or less, which is not preferable. Furthermore, regarding ink stain resistance, the lower the amount of Si in the material, the less ink stain in non-image areas. According to detailed experiments conducted by the present inventors, it has been found that in order to obtain good ink stain resistance, the amount of Si in the material needs to be 0.08% or less. This region where Si is 0.08% or less is the region below the straight line EF in FIG. If the Si content is more than 0.08%, ink will adhere to non-image areas during printing, making printed matter more likely to become stained. Furthermore, the intermediate annealing temperature T is as explained later.
It needs to be within the range of 300 to 550°C, and this range is the area on the right side of the straight line GH and the left side of the straight line IJ in FIG. After all, if we summarize the above conditions with respect to Figure 1, the diagonally shaded area surrounded by the four straight lines AB, CD, EF, and IJ, that is, the area within the range of P ₁ - _{P 2} - _{P 3} - P ₄ , is Satisfies the three properties mentioned above, namely surface treatment properties, burning properties, and ink staining properties.
The range of Si content and intermediate annealing temperature. In addition, as mentioned above, the position of the straight line AB increases or decreases depending on the amount of (Cu−Mg) according to equation (1), and (Cu−Mg)
If the amount decreases to 0%, the straight line AB will coincide with the straight line EF. Therefore, in order for the region _P1 - _P2 - _P3 - _P4 to actually exist, the amount of (Cu-Mg) needs to be 0% or more. On the contrary, (Cu−
As the amount of Mg) increases, the straight line AB will move downward,
The area that satisfies the three characteristics will expand. However, as will be described later, the maximum amount of Cu is 0.03% and the minimum amount of Mg is 0%, so the maximum amount of (Cu-Mg) is 0.03%.
Therefore, the amount of (Cu-Mg) was specified to be in the range of 0.03 to 0% as shown in equation (3). Note that (Cu−
If the amount of Mg) is 0.03% or less, burning property,
It has no effect on ink staining properties. Furthermore, the reasons for limiting the components other than Si among the material components of the printing aluminum alloy base plate of the present invention will be explained. If Fe is less than 0.05%, surface treatment properties are poor and mechanical properties are also insufficient. On the other hand, if Fe exceeds 1.0%, the ink stain resistance deteriorates and the color tone after surface roughening treatment becomes too dark, which is not preferable. Therefore, Fe is 0.05 ~
It was set within the range of 1.0%. Ti is added to make the crystal grains of the ingot uniform and fine, but if it exceeds 0.10%, its effect will be saturated and it will only unnecessarily increase costs, so it should be limited to 0.10% or less. did. Note that as a means for adding Ti for this purpose, it is more effective to use an Al-Ti-B mother alloy than to use an Al-Ti mother alloy. In this case, B is contained, but it is preferable to suppress the B content to 0.02% or less in order to prevent the generation of linear defects due to TiB ₂ particles. Cu is added to improve surface treatment properties, but if added in excess of 0.03%, ink staining properties deteriorate, so the upper limit of Cu was set at 0.03%. Mg, which is an impurity, deteriorates surface treatment properties, but if Mg is within 0.03%, it coexists with an appropriate amount of Cu and does not deteriorate surface treatment properties.
If Mg exceeds 0.03%, surface treatment properties deteriorate even if it coexists with Cu, so Mg needs to be regulated to 0.03% or less. Other impurities that are unavoidably contained in trace amounts do not particularly adversely affect surface treatment properties, ink staining properties, and burning properties. Next, to explain the manufacturing process conditions of the printing aluminum alloy base plate of the present invention, the process conditions before the intermediate annealing process do not particularly affect surface treatment properties, burning properties, and ink stain resistance, and therefore are normal. You should adopt this method. In other words, in the process up to intermediate annealing, the surface of the semi-continuously cast ingot is removed by face milling, then homogenized if necessary, and heated to a predetermined temperature before hot rolling. The coil is hot-rolled and then cold-rolled at a processing rate of 20 to 95%, or a continuously cast coil with a thickness of 12 mm or less is directly cast and then cold-rolled without going through the hot-rolling process. adopt. After reaching the intermediate thickness in this way, it is subjected to intermediate annealing at 300 to 550°C for up to 24 hours, followed by final cold rolling at a working rate of 20 to 95% to obtain the necessary mechanical strength. administer. The reasons for limiting the intermediate annealing conditions are as follows. That is, the intermediate annealing temperature is 300
At temperatures below 550°C, sufficient recrystallization does not occur, making it unsuitable for casting annealing.On the other hand, at temperatures above 550°C, secondary recrystallization occurs, causing the recrystallized grains to become significantly coarser and causing unevenness due to surface oxidation. Blisters occur and the plate becomes unsuitable as a printing plate. Note that the intermediate annealing temperature is actually regulated also by the relationship with the amount of Si in the material as described above. On the other hand, the intermediate annealing time is set to a maximum of 24 hours because if it exceeds 24 hours, the annealing effect will be saturated and it will only be economically disadvantageous. The effects of this invention will be clarified with examples below. Examples Various inventive alloys and comparative alloys shown in sample numbers 1 to 11 in Table 1 were melted and semi-continuously cast to 450
It was cast into a slab of mm x 1200 mm x 3500 mm. After facing the slab by 7mm on each side,
Homogenization treatment at 550°C for 12 hours followed by 500°C
Hot rolling was started, and a hot-rolled plate with a thickness of 5 mm was completed. Next, after cold rolling to a thickness of 1.2 mm, this was intermediately annealed in a stationary annealing furnace at each temperature shown in Table 2. The temperature increase rate during this stationary annealing is approximately 50
°C/Hr, and the holding time after reaching the annealing temperature was 2 hours. Next, the coil after this intermediate annealing is made into a plate with a plate thickness.
A base plate for offset printing was obtained by cold rolling to 0.3 mm. The Si content and intermediate annealing temperature of these samples 1 to 11 are plotted with x marks in FIG. In FIG. 2, the line A-P ₄ -P ₃ -B indicates the lower limit of the amount of Si (0.04%) according to the above formula (1) when the amount of (Cu-Mg) is 0.01%, and the line A'-P _4′−
P ₃ '-B indicates the lower limit of the amount of Si (0.02%) according to the above formula (1) when the amount of (Cu-Mg) is 0.015%. After roughening the surface of each blank plate obtained in this example mechanically by brushing, it was pre-etched in a 10% NaOH aqueous solution at 50°C for 1 minute, followed by alternating current etching at 35°C using a nitric acid-based etching solution. The surface was roughened electrochemically by electrolysis. Thereafter, a 1 μm thick anodic oxide film was formed by anodizing in a 15% H ₂ SO ₄ bath, and then a photosensitizer was applied to produce a PS plate for offset printing.
After the prescribed exposure and development treatment, 280℃ x 7
Burning treatment was applied. Using the original plate thus obtained, a 100,000-copy printing test was conducted in the presence of dampening water. Table 2 also shows the results of investigating the performance of these invention alloys and comparative alloys. Regarding the surface treatment properties, it was checked whether the roughness of the roughened surface after the electrochemical surface roughening treatment was uniform, and the results were classified as ○: good, and ×: poor. The strength after burning is
It is shown as the 0.2% proof stress value after burning treatment at 280°C for 7 minutes. Regarding ink stain resistance, we checked the stains in the non-image area after printing 100,000 copies, ○...Good, ×
...Distinguished by defect.

【table】

【table】

[Table] As shown in Table 2, in the case of aluminum alloy base plates for printing within the scope of this invention (sample number 1,
2 and 3) are clearly superior in all aspects of surface treatment properties, burning properties, and ink staining properties. On the other hand, among the comparative example alloys (sample numbers 4 to 11), sample numbers 4, 5, 8, 10, and 11 do not satisfy formula (1) above in relation to the amount of Si in (Cu-Mg), so In addition, sample numbers 7, 8, 9, and 10 have poor yield strength after burning treatment because the amount of Si does not satisfy the above formula (2) in relation to the intermediate annealing temperature. , 10, 11
Since the Si content exceeds 0.08%, the ink stain resistance is poor. Therefore, it can be seen that in order to satisfy all of the surface treatment properties, burning properties, and ink staining properties, it is necessary to satisfy all the conditions of the present invention. In the above embodiments, intermediate annealing was performed by stationary batch annealing, but it is also possible to perform annealing by passing the coil through a heating furnace maintained at a high temperature while unwinding it. Of course, intermediate annealing using a continuous annealing method may be applied. As is clear from the above description, the printing aluminum alloy base plate of the present invention has excellent surface treatment properties for surface roughening treatment, and can form irregularities evenly and evenly through surface roughening treatment. It is possible to obtain an appropriate color tone through surface roughening treatment, and it also has excellent burning properties, resulting in less decrease in mechanical strength after burning treatment, which improves printing durability and shortens burning treatment time. This makes it possible to perform a burning process at high temperatures for a short time, and it also has excellent ink stain resistance.
It was possible to effectively prevent printed matter from staining due to ink adhesion to non-image areas during printing, and when printing with a printing plate using this base plate, good printed matter could be obtained. Therefore, the printing aluminum alloy base plate of the present invention is extremely useful as a support for offset printing or a support for lithographic printing.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the Si content (wt%) in the aluminum alloy material of the present invention and the condition range of intermediate annealing temperature (°C), and Fig. 2 shows the Si content and condition range of each alloy of the examples. 2 is a diagram showing intermediate annealing temperatures plotted on a diagram similar to FIG. 1; FIG.

Claims (1)

[Scope of Claims] 1. In an aluminum alloy base plate for printing obtained by subjecting an aluminum alloy material to intermediate annealing at 300 to 550°C for 24 hours or less and then cold rolling at a processing rate of 20 to 95%, the alloy of the material The composition is less than 0.08% Si (weight%, same below), less than 0.05 to 1.0% Fe, less than 0.03% Cu,
Ti 0.10% or less, Mg 0.03% or less as impurities,
The remainder is considered as inevitable impurities and Al, and the amount of Si (Si%) is as follows (1) depending on the amount of Cu (Cu%), the amount of Mg (Mg%), and the intermediate annealing temperature T (℃),
It is within the range that satisfies formula (2), and the amount of Cu and Mg
An aluminum alloy base plate for printing, characterized in that the difference in quantity is within a range that satisfies the following formula (3). (Si%)≧0.08−4 {(Cu%)−(Mg%)} ……(1) (Si%)≦2T/625−1.28 …(2) 0≦{(Cu%)−(Mg% )｝≦0.03 ……(3)