JP2009030129A - Aluminum alloy plate for planographic printing plate, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy plate for a planographic printing plate having excellent uniformity in appearance after roughening treatment and stain resistance, and also having excellent thermal softening resistance. <P>SOLUTION: The aluminum alloy plate for a planographic printing plate is composed of an aluminum alloy having a composition containing 0.1 to 0.5% Fe, 0.01 to 0.20% Si, 0.005 to 0.07% Cu, 0.10 to 0.25% Mg, 0.003 to 0.03% Ti and 0.0005 to <0.004% Zr, and the balance Al with inevitable impurities, and in which the amount of simple substance Si is ≤0.02%. The average length of crystal grains in a direction perpendicular to the rolling direction is ≤100 μm, and further, heat treatment temperature at which a proof stress difference before and after heat treatment in a product plate reaches 1/2 of a proof stress difference between that before heat treatment and that after heating at 500°C for 10 min is ≥240°C. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an aluminum alloy plate used for a lithographic printing plate formed by anodizing the surface of a roughened aluminum alloy plate and further applying a photosensitive material. The present invention relates to an aluminum alloy plate for a lithographic printing plate excellent in uniformity in appearance after surface treatment and ink stain resistance in non-image areas, and excellent in heat-resistant softening properties, and a method for producing the same.

  In general, a lithographic printing plate is usually used by applying a photosensitive substance on a support obtained by subjecting the surface of aluminum or an aluminum alloy to a surface treatment such as a roughening treatment or an anodized film treatment. Among such lithographic printing plates, what is usually widely used is a so-called PS plate in which a photosensitive material is previously applied on a support and is ready to be baked.

  When such a lithographic printing plate is actually used as a printing plate, plate making processes such as image exposure, development, washing, and lacquer are applied. Here, the undissolved photosensitive layer formed by the development process forms an image portion, and the portion where the photosensitive layer is removed and the alumite layer under the photosensitive layer is hydrophilic becomes a water receiving portion because of hydrophilicity, and forms a non-image portion. The printing plate made in this way is wound around a rotating cylindrical plate cylinder of a printing press, and ink is deposited on the image area in the presence of fountain solution, transferred to a rubber blanket, and printed on the paper surface. Will be printed.

  Conventionally, JIS1050, JIS1100, JIS3003, etc. are mainly used as aluminum and aluminum alloys (hereinafter collectively referred to as aluminum alloys) for such applications. Usually, these aluminum alloy plates are roughened by a roughening method using a mechanical method, a chemical method, an electrochemical method, or a combination of two or more, and then preferably an anode. Used with oxidation treatment.

  By the way, in recent years, for the purpose of improving printing durability, it has been widely practiced to reinforce the image area by subjecting the lithographic printing plate to exposure and development processing by a usual method and then heat treatment (burning treatment) at high temperature. Yes. The burning treatment is usually performed under the conditions of a heating temperature of 200 to 290 ° C. and a heating time of 3 to 9 minutes. However, in order to prevent the strength of the aluminum alloy plate from being reduced during such burning treatment, It is desired that the burning property is excellent.

  In addition, printing plates are required to be able to print more clearly, and there is a strong demand to be able to print a larger number of copies using the same printing plate. It is particularly important that no ink smear occurs in the image area.

  As measures for satisfying these requirements, the appearance uniformity after heat roughening and heat softening resistance are already resolved by prescribing various temperatures in hot rolling and the average cooling rate after hot rolling. Proposals have been made (see, for example, Patent Document 1).

  On the other hand, there is also a proposal for solving the appearance uniformity after the surface roughening treatment by adjusting the distribution of AlFe-based intermetallic compound particles that are metastable phases (see, for example, Patent Document 2).

  Furthermore, by applying specific hot rolling conditions to the aluminum alloy material with the added amount of various elements adjusted to control the crystal grain size, the appearance uniformity after the surface roughening treatment, heat softening resistance, repetitiveness Proposals for solving the bending fatigue strength have also been made (see, for example, Patent Document 3).

  In addition, proposals have been made to solve the appearance uniformity and heat-softening resistance after the roughened surface by adjusting the addition amount of various elements (see, for example, Patent Document 4).

In addition, there is an example in which roughening uniformity is solved by adjusting intermetallic compound particles in the metastable layer (see, for example, Patent Document 5).
Japanese Patent Laid-Open No. 10-306355 JP 2002-088434 A JP 2004-250794 A JP 2005-015912 A JP-A-2005-002429

  Among the conventional proposals as described above, in the proposal shown in Patent Document 1, it is difficult to obtain sufficient heat-softening property only by controlling each temperature in hot rolling. It has been found that it is difficult to make crystal grains fine only by controlling the speed, and the appearance uniformity after the surface roughening treatment is not sufficient.

  In the case of the proposal shown in Patent Document 2, it cannot be said that the appearance uniformity after the roughening treatment is necessarily good only by controlling the metastable phase particles, and further improvement is necessary. .

  Furthermore, in the case of the proposal shown in Patent Document 3, there is a region that is not hot-rolled and recrystallized on the plate surface. In this case, streaks occur on the roughened surface, and the appearance is uniform. There is a problem inferior to

  In the case of the proposal shown in Patent Document 4, since the Mn content of the aluminum alloy is large, an Al—Mn-based coarse compound is likely to be generated, and in this case, a large drop mark of the Al—Mn-based coarse compound is generated. There is a problem that the appearance uniformity after the roughening treatment is inferior.

  In addition, in the proposal shown in Patent Document 5, the alloy composition is adjusted, and at the same time, the control of the metastable phase intermetallic compound particles is not performed. Although this method is carried out at a low temperature, this method results in an insufficient amount of solid solution of Fe, so that the difference in proof stress before and after the heat treatment specified in the present invention cannot be satisfied, and the heat softening property is inferior. It will be enough. That is, the heat treatment temperature at which the difference in yield strength before and after the heat treatment when the heat treatment is performed at a certain temperature is 1/2 or more of the difference in yield strength before and after the heating at 500 ° C. is that the heat treatment temperature is 240 ° C. or more. However, the actual situation is that the strength reduction during the burning treatment becomes large and sufficient heat-softening property cannot be ensured.

  The present invention has been made against the background of the above circumstances, without impairing the performance required for ordinary lithographic printing plates, such as uniformity of appearance after roughening treatment and ink stain resistance of non-image areas. An object of the present invention is to provide an aluminum alloy plate for a lithographic printing plate that has good softening properties and is less likely to be reduced in strength by a burning treatment.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that the above-described problems can be solved by strictly adjusting the content of a trace amount of additive elements such as Zr. The present invention has been completed based on such findings.

  That is, the aluminum alloy plate for a lithographic printing plate according to the first aspect of the present invention comprises Fe 0.1 to 0.5%, Si 0.01 to 0.20%, Cu 0.005 to 0.07%, Mg 0.10 to 0.25. %, Ti 0.003 to 0.03%, Zr 0.0005% or more, less than 0.004%, the balance being an aluminum alloy plate made of Al and inevitable impurities, and the amount of simple Si in the plate is The average length of the crystal grains in the direction perpendicular to the rolling direction is not more than 100 μm and the proof stress YSO before heating when the plate is heated at 500 ° C. for 10 minutes and heating The difference between the proof stress value YSA after that is ΔYSA (= YSO−YSA), and the proof stress value YSO before the heat treatment and the proof stress value YSB after the heat treatment when the heat treatment is performed for 10 minutes at a certain temperature on the plate. The difference between the above and the difference is ΔYSB (= YSO−YSB), and the heat treatment temperature that satisfies the expression (1) is 240 ° C. or more.

  The aluminum alloy plate for a lithographic printing plate according to the second aspect of the present invention comprises Fe 0.1 to 0.5%, Si 0.01 to 0.20%, Cu 0.005 to 0.07%, Mg 0.10 to 0.25. %, Ti 0.003-0.03%, Zr 0.0005% or more, less than 0.004%, Mn 0.001-0.01%, Zn 0.001-0.01%, the balance being Al and inevitable An aluminum alloy plate made of impurities, the amount of elemental Si in the plate is 0.02% or less, and the average length of crystal grains in the direction perpendicular to the rolling direction is 100 μm or less, and the plate The difference between the proof stress value YSO before heating and the proof stress value YSA after heating when heated at 500 ° C. for 10 minutes is ΔYSA (= YSO−YSA), and heat treatment is held for 10 minutes at the temperature on the plate. Done The difference between the proof stress value YSO before the heat treatment and the proof stress value YSB after the heat treatment is ΔYSB (= YSO−YSB), and the heat treatment temperature satisfying the formula (1) is 240 ° C. or more. It is.

  On the other hand, the method for producing an aluminum alloy plate for a lithographic printing plate according to claim 3 is as follows: Fe 0.1-0.5%, Si 0.01-0.20%, Cu 0.005-0.07%, Mg 0.10 0.25%, Ti 0.003-0.03%, Zr 0.0005% or more, less than 0.004%, with the balance being aluminum alloy consisting of Al and inevitable impurities, heat to the ingot In performing the hot rolling, the reduction amount in the final rolling pass is 3 mm or more, the hot rolling up temperature is in the range of 280 to 360 ° C., and the hot rolling up plate thickness is in the range of 1.0 to 4.0 mm. The obtained hot-rolled sheet is then cold-rolled to a product sheet thickness without intermediate annealing, and the average length of crystal grains in a direction perpendicular to the rolling direction is 100 μm or less and single Si amount is 0.02% or less In addition, the difference between the proof stress value YSO before heating and the proof stress value YSA after heating when heated at 500 ° C. for 10 minutes is ΔYSA (= YSO−YSA), and the heat treatment is held for 10 minutes at the temperature on the plate. The difference between the proof stress value YSO before the heat treatment and the proof stress value YSB after the heat treatment is ΔYSB (= YSO−YSB), and the heat treatment temperature satisfying the formula (1) is 240 ° C. or more. To do.

  Moreover, the manufacturing method of the aluminum alloy plate for planographic printing plates of the invention of Claim 4 is Fe0.1-0.5%, Si0.01-0.20%, Cu0.005-0.07%, Mg0.10-0. 0.25%, Ti 0.003-0.03%, Zr 0.0005% or more, less than 0.004%, Mn 0.001-0.01%, Zn 0.001-0.01%, the balance being Al In addition, when an aluminum alloy made of inevitable impurities is used as a raw material and the hot rolling is performed on the ingot, the amount of reduction in the final rolling pass is 3 mm or more, the hot rolling up temperature is in the range of 280 to 360 ° C., hot The rolled up sheet thickness is controlled to be within a range of 1.0 to 4.0 mm, and the obtained hot-rolled sheet is then cold-rolled to the product sheet thickness without intermediate annealing, and the rolling direction Average length of grains perpendicular to The difference between the proof stress YSO before heating and the proof stress YSA after heating when heated at 500 ° C. for 10 minutes is ΔYSA (= YSO−YSA). And the difference between the proof stress value YSO before the heat treatment and the proof stress value YSB after the heat treatment when the heat treatment is performed for 10 minutes at a certain temperature on the plate is defined as ΔYSB (= YSO−YSB). ) The heat treatment temperature that satisfies the formula is 240 ° C. or higher.

  The aluminum alloy plate for a lithographic printing plate according to the first and second aspects of the present invention is excellent in the uniformity of the appearance after the roughening treatment, and at the same time, is excellent in the ink stain resistance of the non-image area. The heat resistance softening property is excellent, the strength is not significantly lowered by the burning treatment, and therefore, the lithographic printing plate support has extremely good performance and commercial value.

  Moreover, according to the manufacturing method of the invention of Claim 3 and Claim 4, the aluminum alloy plate for lithographic printing plates which has the above outstanding performance and commercial value can be obtained reliably and stably, and it is only that. In addition, by omitting the intermediate annealing after the hot rolling, it is possible to reduce the number of processes and reduce the cost by saving energy.

  The present invention will be described in detail below.

  First, the reasons for limiting the component composition of the aluminum alloy used in the present invention will be described.

Fe: 0.1 to 0.5%
If the amount of Fe is less than 0.1%, the crystal grain size at the time of recrystallization becomes coarse, and the pits generated by the roughening treatment become non-uniform, resulting in uneven surface quality on the appearance after the roughening treatment. Occurs and the appearance becomes uneven. On the other hand, if the amount of Fe exceeds 0.5%, a large amount of Al-Fe-based and Al-Fe-Si-based coarse compounds are generated, and the pits after the surface roughening treatment become non-uniform. Appearance non-uniformity after crystallization treatment occurs. Therefore, the amount of Fe is set in the range of 0.1 to 0.5%. More preferably, the amount of Fe is in the range of 0.12 to 0.29%.

Si: 0.01-0.20%
If the amount of Si is less than 0.01%, the pits after the surface roughening treatment will be non-uniform, resulting in surface unevenness after the surface roughening treatment, and the appearance will be non-uniform. On the other hand, if the amount of Si exceeds 0.20%, a large amount of Al-Fe-Si-based coarse compounds are produced, and the pits after the surface roughening treatment become non-uniform, resulting in surface quality unevenness after the surface roughening treatment. In addition, the appearance becomes non-uniform, and further, precipitation of simple substance Si, which will be described later, is likely to occur, so that ink stains in non-image areas are also likely to occur. Therefore, the Si amount is set in the range of 0.01 to 0.20%. Preferably, the Si amount is in the range of 0.03 to 0.15%.

Cu: 0.005-0.07%
Cu is an element that greatly affects the electrolytic graining property. If the amount of Cu is less than 0.005%, the pits after the surface roughening treatment become non-uniform, and the appearance becomes non-uniform as described above. On the other hand, even if the amount of Cu exceeds 0.07%, the pits after the surface roughening treatment become non-uniform, and the color tone after the surface roughening treatment becomes too blackish, thereby impairing the commercial value. Therefore, the amount of Cu is set within a range of 0.005 to 0.07%. In addition, Preferably Cu amount shall be in the range of 0.005-0.05%.

Mg: 0.10 to 0.25%
Mg is an element that promotes recrystallization and is mostly dissolved in aluminum to improve heat softening resistance. Moreover, since Mg precipitates as Mg ₂ Si, it also serves to reduce the amount of elemental Si. If the Mg content is less than 0.10%, these effects cannot be sufficiently obtained. On the other hand, if the Mg content exceeds 0.25%, the pits after the surface roughening treatment become non-uniform and the appearance is also non-uniform. Become.

Zr: 0.0005% or more and less than 0.004% Zr improves the cathode dissolution efficiency during the electrolytic surface roughening treatment, and is a rough surface due to a subtle shape difference of etch pits formed by the surface roughening treatment. This has the effect of suppressing the occurrence of striped patterns on the surface. If the amount of Zr is less than 0.0005%, it is difficult to sufficiently obtain this effect. On the other hand, if the amount of Zr is 0.004% or more, it will precipitate as Al ₃ Zr in the process of casting and rolling, causing streaks. If streaks occur, the pits after the roughening process become non-uniform and the appearance uniformity is impaired. Therefore, the amount of Zr is set in the range of 0.0005% or more and less than 0.004%. A more preferable Zr amount is in the range of 0.001 to 0.003%.

Ti: 0.003 to 0.03%
Ti is an element having a great influence on the electrolytic graining property and also having a great influence on the structure of the aluminum alloy ingot. If the amount of Ti is less than 0.003%, the pits after the surface roughening treatment become non-uniform, and the crystal grains of the ingot are not refined and become a coarse crystal grain structure. A band-shaped streak is generated, and the strip-shaped streak remains after the roughening treatment, which is not preferable as a support for a lithographic printing plate. On the other hand, if the amount of Ti exceeds 0.03%, not only the above effect is saturated, but also a coarse Al-Ti compound is formed, and the compound is distributed in a streak pattern on the rolled plate. Defects occur, resulting in defects in the photosensitive layer, making it difficult to print cleanly. Therefore, the Ti amount is set in the range of 0.003 to 0.03%. A more preferable Ti amount is in the range of 0.005 to 0.03%.

In general, in an aluminum alloy plate, Ti may be added in combination with a small amount of B in order to refine the ingot crystal structure and prevent texture and streak of the rolled plate. Even in an aluminum alloy, it is permissible to add a small amount of B together with Ti. However, if the amount of B is less than 1 ppm, the above effect cannot be obtained. On the other hand, if the amount of B exceeds 50 ppm, not only the addition effect of B is saturated, but also linear defects due to coarse TiB ₂ particles tend to occur. When B is added, the amount of B added is preferably in the range of 1 to 50 ppm.

  In addition to the above elements, basically, Al and inevitable impurities may be used. In the case of the aluminum alloy plate for lithographic printing plates according to the invention of claim 2, in addition to the above elements, Mn, Zn It shall contain. The reason for these additions is as follows.

Mn: 0.001 to 0.01%
Mn has an effect of making the electrolytic rough surface uniform, and in order to obtain this effect sufficiently, it is necessary to add 0.001% or more of Mn. On the other hand, if the amount of Mn exceeds 0.01%, a large amount of Al-Fe-Mn-based or Al-Fe-Mn-Si-based coarse compound is generated, and the pits after the surface roughening treatment become non-uniform. . Therefore, the range of the amount of Mn is set to 0.001 to 0.01%.

Zn: 0.001 to 0.01%
Most of Zn is dissolved in the aluminum matrix, and the effect of adjusting the potential difference between the aluminum matrix and the intermetallic compound and making the electrolytic rough surface uniform is exhibited. If the Zn content is less than 0.001%, such a potential difference adjusting effect cannot be obtained. On the other hand, if the Zn content exceeds 0.01%, the entire surface is dissolved during the electrolytic roughening, and a nonuniform electrolytic rough surface is formed. Therefore, the Zn content is set in the range of 0.001 to 0.01%.

  In the aluminum alloy plate for a lithographic printing plate of the invention of claim 1, Mn and Zn are not defined as the component elements, but the aluminum alloy plate for a lithographic printing plate of the invention of claim 1 is also defined in claim 2. Of course, it is allowed to contain Mn and Zn as impurities less than the specified Mn amount (0.001 to 0.01%) and Zn amount (0.001 to 0.01%).

  In the aluminum alloy plate for a lithographic printing plate according to the present invention, in addition to the component elements as described above, inevitable impurities are usually included. As the inevitable impurities, the amount of impurities equivalent to JIS 1050 (total of others) 0.05% or less), the characteristics of the aluminum alloy plate for a lithographic printing plate are not impaired.

  Furthermore, in the aluminum alloy plate for lithographic printing plates according to the present invention, the amount of elemental Si contained in the product plate needs to be 0.02% or less. That is, the simple Si remains in the anodized film after the anodizing treatment to form a film defect, and this defect becomes a starting point for occurrence of stains in the non-image area during printing, and causes deterioration in stain resistance. Therefore, it is necessary to regulate the amount of simple Si to 0.02% or less.

  Moreover, in the aluminum alloy plate for a lithographic printing plate according to the present invention, as the crystal grain size condition, the average length of crystal grains in the direction perpendicular to the rolling direction on the surface needs to be within a range of 100 μm or less. If the average length of the crystal grains in the direction perpendicular to the rolling direction is larger than 100 μm, surface quality unevenness occurs after the surface roughening treatment, and the appearance becomes non-uniform. Such control of the crystal grain size can be carried out by controlling hot rolling conditions described later.

In the aluminum alloy plate for a lithographic printing plate of the present invention, as an index of heat-resistant softening properties, the difference in proof strength before and after heating when heated at 500 ° C. for 10 minutes is used as a reference (reference proof stress difference) for 10 minutes. It defines that the heat treatment temperature at which the difference in proof stress before and after the heat treatment is ½ of the above-mentioned standard proof stress value is 240 ° C. or higher. That is, the difference between the proof stress value YSO before heating and the proof stress value YSA after heating when the plate is heated at 500 ° C. for 10 minutes is defined as ΔYSA (= YSO−YSA) and is in the plate. The difference between the proof stress value YSO before the heat treatment and the proof stress value YSB after the heat treatment when the heat treatment is held for 10 minutes at the temperature is ΔYSB (= YSO−YSB).
ΔYSB ≧ ΔYSA × 1/2 (1)
It is necessary that the heat treatment temperature that satisfies the above is 240 ° C. or higher. By satisfying such a condition, it is possible to suppress the strength reduction to a level that does not substantially hinder the burning treatment. . If the heat treatment temperature satisfying the above formula is less than 240 ° C., the strength decrease during the burning treatment becomes large, and it cannot be said that the heat resistance softening property is sufficient.

  Here, controlling the heat treatment temperature satisfying the above formula (1) to be 240 ° C. or higher appropriately sets the range of the amount of Mg that fulfills the function of improving the heat-resistant softening characteristics by dissolving the majority in the matrix. It is possible to achieve this by making the amount of solid solution of Fe and Mg as small as possible by adjusting to the above and appropriately controlling the hot rolling conditions described later.

  Next, the manufacturing method of this invention is demonstrated.

  First, the molten aluminum alloy adjusted to the component composition range as described above is cast according to a conventional method such as a DC casting method, and the resulting ingot is subjected to a homogenization treatment as necessary, as described later. Hot rolling in accordance with various conditions, and then cold rolling without intermediate annealing to obtain a product plate having a required thickness. Here, the conditions for the homogenization treatment are 550 ° C. in order to make the intermetallic compound a stable phase and increase the amount of Fe solid solution, thereby suppressing a decrease in yield strength before and after heating and improving heat-resistant softening characteristics. It is preferable to maintain the temperature within a range of over 600 ° C. for 1 hour or longer (usually within 10 hours).

  The start temperature of hot rolling is not particularly limited as long as it is a temperature at which a hot rolling up temperature as described later can be secured, but it is usually 400 to 550 ° C. Regarding hot rolling conditions after the start of hot rolling, the ascending temperature is in the range of 280 to 360 ° C., the amount of reduction in the final pass is 3 mm or more, and the ascending plate thickness is in the range of 1.0 to 4.0 mm. There is a need. The reasons for setting these conditions are as follows.

Hot rolling up temperature: 280-360 ° C
If the hot rolling ascending temperature is lower than 280 ° C., the unrecrystallized structure remains without being recrystallized in the hot rolled sheet cross section, and the base plate strength becomes too high. In this case, unrecrystallized portions remain on the surface of the hot-rolled plate, streaks may occur as an appearance after the roughening treatment, and the appearance may be uneven. The amount of precipitation increases, and as a result, the solid solution amount of Fe and Mg also decreases, and the heat softening resistance also decreases. On the other hand, when the hot rolling ascending temperature is higher than 360 ° C., the recrystallized grains become coarse, and in this case also, the appearance after the roughening treatment becomes non-uniform. Therefore, in order to appropriately cause recrystallization to prevent occurrence of non-uniform appearance and to obtain an appropriate strength, it is necessary to set the hot rolling ascending temperature within a range of 280 to 360 ° C. The hot rolling up temperature is preferably in the range of 290 to 350 ° C. even within the above range.

Hot rolled up plate thickness: 1.0 to 4.0 mm
When the hot rolled sheet obtained by hot rolling is cold rolled to a predetermined product sheet thickness, the thickness of the hot rolled sheet (hot rolled up sheet thickness) is from 1.0 mm. If it is small, the strength of the base plate due to work hardening in cold rolling cannot be sufficiently increased, resulting in insufficient strength, and a predetermined heat-resistant softening property cannot be obtained. On the other hand, if the hot rolled up plate thickness is larger than 4.0 mm, the base plate strength becomes too high due to work hardening by cold working when the predetermined product plate thickness is obtained by cold rolling. There is a possibility that the aluminum alloy is cut when it is wound around the plate cylinder.

Rolling amount of the final rolling pass in hot rolling: 3 mm or more If the rolling amount of the final pass is less than 3 mm, sufficient strain cannot be given, and therefore it becomes difficult to recrystallize after hot rolling, An unrecrystallized structure remains on the plate surface, and the appearance after the roughening treatment becomes non-uniform. In this case, even if recrystallization is performed, coarse crystal grains are generated, and the appearance after the surface roughening treatment is similarly uneven. The upper limit of the amount of reduction in the final hot rolling pass is not particularly limited, but is preferably 10 mm or less.

  After hot rolling, it may be wound into a coil according to a conventional method and then finished to the required product thickness by cold rolling without annealing. Here, in the state in which the coil is wound by hot rolling, recrystallization is caused by self-annealing by the self-holding heat of the hot-rolled sheet as described above, so it is necessary to perform annealing for recrystallization again. Absent. The conditions for cold rolling are not particularly limited, and may be determined according to the required product plate strength and plate thickness. Usually, the rolling rate may be 60 to 98%.

  In order to actually use the thus obtained lithographic printing plate aluminum alloy plate (product plate) as a lithographic printing plate support, surface treatment for roughening or the like is performed. The surface treatment method is not particularly limited, and may follow a conventional method. A typical surface treatment method will be described below.

  Surface treatment methods for surface roughening include electrochemical surface roughening treatment using electrochemical graining in hydrochloric acid or nitric acid electrolyte, wire brush grain method, grinding ball with metal wire. Any of the above rough surfaces can be used, such as a ball grain method in which the aluminum surface is grained with an abrasive and an abrasive, or a mechanical graining method such as a brush grain method in which the surface is roughened with a nylon brush and an abrasive. The conversion methods can be used alone or in combination.

In general, the aluminum alloy plate thus roughened is chemically etched with acid or alkali as a second step of roughening. When an acid is used as an etching agent, it takes a long time to destroy the fine structure, which is industrially disadvantageous, but it can be improved by using an alkali as the etching agent. As the alkali agent for etching, caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide, etc. can be used, and the preferred ranges of concentration and temperature are respectively It is preferable that the conditions be 1 to 50%, 20 to 100 ° C., and the conditions that the dissolution amount of Al during etching is 5 to 20 g / m ² .

  After the etching, acid cleaning is usually performed to remove dirt (smut) remaining on the surface. Examples of the acid used for the acid cleaning include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid. In particular, for removing smut after the electrochemical surface roughening treatment, a method of contacting with 15 to 65% by weight of nitric acid at a temperature of 50 to 90 ° C. as described in JP-A-53-12739 is preferable. In addition, there is an alkali etching method described in Japanese Patent Publication No. 48-28123.

The aluminum alloy plate treated as described above can be used as a support for a lithographic printing plate, but it is usually desirable to perform further treatments such as anodizing treatment and caustic treatment. The anodizing treatment can be performed by a method conventionally used in this field. Specifically, by flowing direct current or alternating current through an aluminum alloy plate in an aqueous solution or non-aqueous solution of sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, etc., or a combination of two or more thereof. An anodized film can be formed on the surface. The conditions for anodization vary depending on the electrolyte used, and are not generally determined. In general, however, the electrolyte concentration is 1 to 80%, the solution temperature is 5 to 70 ° C., and the current density is 0.5 to 60 A / day. dm ² , voltage 1 to 100 V, and electrolysis time 10 to 100 seconds are appropriate.

  In finishing the aluminum alloy plate support for a lithographic printing plate obtained as described above into a PS plate, a photosensitive layer or an intermediate layer and a photosensitive layer may be applied and dried according to a conventional method.

No. in Table 1 1-No. The alloy having each component composition shown in No. 18 was made into an ingot having a thickness of 600 mm by the DC casting method. 17, no. No. 18 other than No. 18 1-No. No. 16 was subjected to a homogenization treatment held at 560 ° C. for 3 hours, then started hot rolling at 450 ° C., rolled under the hot rolling conditions shown in Table 2, and thereafter subjected to cold annealing without intermediate annealing. The product was rolled to a final plate thickness of 0.3 mm by hot rolling to obtain a product plate (aluminum alloy plate for planographic printing plates). Alloy No. No homogenization treatment was performed for No. 17, and alloy no. For No. 18, homogenization was performed under the conditions of 450 ° C. × 3 hours, and the other conditions were the same as described above. Furthermore, about the product board, the heat processing temperature with which the proof stress difference before and behind heat processing satisfy | fills said Formula (1) was measured with the following method.
(1) After processing the product plate into a JIS No. 5 test piece, a test piece without heat treatment, and a test piece subjected to heat treatment for 10 minutes at 200 ° C. to 500 ° C. at each temperature every 10 ° C. Each was subjected to a tensile test.
(2) The difference between the proof stress value (YSO) measured without heat treatment and the proof stress value (YSA) measured after heat treatment at 500 ° C. for 10 minutes was defined as ΔYSA (= YSO−YSA).
(3) The difference between the proof stress value (YSO) measured without heat treatment and the proof stress value (YSB) measured after heat treatment held at each temperature of 10 ° C. within the range of 200 to 450 ° C. for 10 minutes is expressed as ΔYSB ( = YSO-YSB).
(4) Compared with ΔYSB and ΔYSA, the temperature when ΔYSB ≧ ΔYSA / 2 was examined. The temperature is a heat treatment temperature that satisfies the equation (1).

  Further, the amount of simple substance Si of the product plate was measured by the analysis method described in JP-A-60-82642.

  Further, the average length of crystal grains in the direction perpendicular to the rolling direction on the product plate surface was examined as follows. That is, after etching the plate surface by the Barker method, a 25-fold photograph was taken under a microscope under polarized light, and the cross line method was used.

  These values are shown in Table 2.

Further, each product plate (aluminum alloy plate for lithographic printing plate) obtained as described above is subjected to alkali etching and desmutting treatment, and then 1% by using a power source having an electrolytic waveform in which polarities are alternately exchanged. Electrolytic roughening was performed by electrolytic etching in nitric acid with an anode electricity quantity of 150 C / dm ² . After washing this in a sulfuric acid bath, the presence or absence of streak generation, uniformity in appearance, and heat softening resistance were evaluated according to the following procedures (1) to (3).
(1) Presence or absence of streak generation The appearance after the surface roughening treatment was visually observed.
(2) Appearance uniformity The appearance after the roughening treatment is visually observed over the entire length of the product plate coil. The product with the rough surface is uniform over the entire length of the product plate coil, and the surface roughness is inferior. X.
(3) Heat softening resistance Regarding the product plate, those having a heat treatment temperature satisfying the above formula (1) of 240 ° C. or higher were evaluated as “○” and those having a heat treatment temperature lower than 240 ° C. as “X”.

Furthermore, after the electrolytic surface roughening treatment was performed as described above, anodization treatment was performed in a 25% sulfuric acid electrolytic bath at a liquid temperature of 25 ° C. under the condition of a current density of 1.5 A / dm ^2. A 5 μm anodic oxide film was formed. A photosensitive layer having the following composition was provided on the surface of the film after the anodizing treatment so that the coating amount upon drying was 2.5 g / m ² .

Composition of photosensitive layer:
Ester compound of naphthoquinone-1,2-diad-5-sulfonyl chloride, pyrogallol, acetone resin ... 0.75g
Cresol noholac resin ... 2.00g
Oil Blue # 603 (Orient Chemical) ... 0.04g
Ethylene dichloride ... 16g
2-methoxyethyl acetate ... 12g

The lithographic printing plate having the photosensitive layer formed in this way was image-exposed for 60 seconds from a distance of 1 m with a 3 kw metal halide lamp, and then the SiO ₂ / Na ₂ O molar ratio was 1.2 and the SiO ₂ content was 1. Developed with 5% sodium silicate aqueous solution, washed with water and dried, and then 200,000 copies were printed using an offset rotary press, and the stain resistance (ink stain resistance of non-image areas) was evaluated as follows. The results are shown in Table 3. That is, after printing 200,000 copies with a printing machine, the non-image portion was checked for stains. Good ones with no stains were marked with ○, ones with slight stains were marked with Δ, and ones with frequent stains were marked with ×.

  As shown in Table 3, No. 4 within the scope of the present invention. 1-No. In the case of No. 7, it was found that none of the streaks occurred, the uniformity of the rough surface was good, and the stain resistance and heat softening resistance were excellent.

  On the other hand, no. 8-No. In 18 comparative examples, any one or more performance was inferior.

  That is, no. In Example 8, since the hot rolling up temperature is low, the processed structure remains on the plate surface, streaks occur, and the Mg content is high, so the uniformity of the roughened surface is poor. It was.

  No. In the example 9, since the Fe content is small and the hot rolling temperature rises off and the hot rolling final pass reduction is small, the recrystallized grains grow and the grain size increases, and the Zr Since there was little content, the striped pattern generate | occur | produced on the roughening process surface and the uniformity of the roughening surface was inferior.

  Furthermore, no. In the example of 10, since the Si content is large and the Mg content is small, a large amount of simple substance Si is precipitated, the stain resistance is inferior, and an Al-Fe-Si based coarse intermetallic compound is generated, The uniformity of the roughened surface was inferior. Moreover, since there was little Mg content, heat-resistant softening property was inferior.

  No. In the example 11, since the Fe content was high, the Si content was small, and the reduction amount in the final hot rolling pass was small, sufficient strain was not given, and as a result, the crystal grains became coarse and the rough surface The uniformity of the chemical surface was inferior. Moreover, since the hot rolled up plate thickness was thin, sufficient heat-resistant softening property could not be obtained.

  No. In Example 12, since the contents of Cu and Mn were large, the uniformity of the roughened surface was inferior. Further, since the hot rolled up plate thickness was large, the crystal grains were extended by cold rolling and streaks were generated. In addition, since the Mg content is large, the strength of the base plate is too high, and the plate is cut when wound around the cylindrical plate cylinder.

  No. In Example 13, since the amount of Cu added was small and the Ti content was large, the uniformity of the roughened surface was poor. In addition, since the hot rolling up temperature was low, the processed structure remained on the plate surface and streaks were generated.

No. In Example 14, since the Mg content was small, a large amount of simple substance Si was precipitated. As a result, the soil resistance was inferior and the heat softening resistance was also inferior. Further, since the Zr content was large, Al ₃ Zr was precipitated and streaks were generated. Furthermore, since there was much Zn content, the whole surface melt | dissolved during the electrolytic surface roughening process, and the uniformity of the roughened surface was inferior.

No. In Example 15, since the Si content was large, a large amount of simple Si was precipitated, and as a result, the stain resistance was poor. Moreover, combined with the fact that Al ₃ Zr was precipitated due to the high Zr content and that the Fe content was not able to sufficiently refine the ingot structure due to the low Ti content, A streak occurred. In addition, the combination of the fact that the recrystallized grain size was increased due to the low Fe content and the fact that the Si content was high and an Al—Fe—Si based coarse intermetallic compound was produced, The uniformity of the surface has been inferior. The fact that the entire surface was dissolved during the electrolytic surface roughening treatment due to the large Mn content was also a cause of poor uniformity of the roughened surface.

No. In Example 16, since the Si content was large, a large amount of simple Si was precipitated, resulting in poor stain resistance. Further, since the Zr content was large and Al ₃ Zr was precipitated, streaks were generated. Furthermore, since the hot rolling ascending temperature deviated to a higher level, the recrystallized grains grew and the crystal grain size increased, resulting in poor uniformity of the roughened surface.

  No. In Example 17, since the Cu content is small and the Ti content is large, the uniformity of the roughened surface is inferior, and since the hot rolling up temperature is low, there is a processed structure on the plate surface, streaks. Occurred.

  No. Even in the example 18, since the Cu content is small and the Ti content is large, the uniformity of the roughened surface is inferior, and the homogenization treatment temperature is low, so the Fe solid solution amount is reduced, and as a result, the heat softening resistance Was inferior.

Claims (4)

Fe 0.1-0.5% (mass%, the same shall apply hereinafter), Si 0.01-0.20%, Cu 0.005-0.07%, Mg 0.10-0.25%, Ti 0.003-0.03 %, Zr 0.0005% or more and less than 0.004%, the balance being an aluminum alloy plate made of Al and inevitable impurities, and the amount of elemental Si in the plate is 0.02% or less, and The average length of crystal grains in the direction perpendicular to the rolling direction is 100 μm or less, and the difference between the proof stress value YSO before heating and the proof stress value YSA after heating when the plate is heated at 500 ° C. for 10 minutes is ΔYSA (= YSO−YSA) and the difference between the proof stress value YSO before the heat treatment and the proof stress value YSB after the heat treatment when the heat treatment is performed for 10 minutes at a certain temperature on the plate is ΔYSB (= YSO−YSB) As, wherein the heat treatment temperature to the following equation (1) is satisfied is 240 ° C. or higher, aluminum alloy strip for lithographic printing plates.
ΔYSB ≧ ΔYSA × 1/2 (1) Fe 0.1-0.5%, Si 0.01-0.20%, Cu 0.005-0.07%, Mg 0.10-0.25%, Ti 0.003-0.03%, Zr 0.0005% or more , Less than 0.004%, Mn 0.001 to 0.01%, Zn 0.001 to 0.01%, the balance being an aluminum alloy plate made of Al and unavoidable impurities, and simple substance Si in the plate The amount is 0.02% or less, the average length of the crystal grains in the direction perpendicular to the rolling direction is 100 μm or less, and the proof stress YSO before heating when the plate is heated at 500 ° C. for 10 minutes. And YSA (= YSO-YSA) as the difference between the proof stress value after heating and the proof stress value after heating, the proof stress value YSO before the heat treatment and the proof stress value after the heat treatment when the heat treatment is performed for 10 minutes at a certain temperature on the plate. With YSB The aluminum alloy plate for a lithographic printing plate is characterized in that the heat treatment temperature at which the following formula (1) is satisfied is 240 ° C. or higher, where ΔYSB (= YSO−YSB).
ΔYSB ≧ ΔYSA × 1/2 (1) Fe 0.1-0.5%, Si 0.01-0.20%, Cu 0.005-0.07%, Mg 0.10-0.25%, Ti 0.003-0.03%, Zr 0.0005% or more When the hot rolling is performed on the ingot, the reduction amount in the final rolling pass is 3 mm or more when hot rolling is performed using an aluminum alloy containing less than 0.004%, the balance being Al and inevitable impurities. Control the temperature so that the ascending temperature is within the range of 280 to 360 ° C. and the hot rolled ascending sheet thickness is within the range of 1.0 to 4.0 mm, and then subject the obtained hot-rolled sheet to intermediate annealing. And cold rolled to the product sheet thickness, the average length of the crystal grains in the direction perpendicular to the rolling direction is 100 μm or less, the amount of elemental Si is 0.02% or less, and heated at 500 ° C. for 10 minutes. Proof stress YSO before heating The difference between the proof stress value YSA after that is ΔYSA (= YSO−YSA) and the proof stress value YSO before the heat treatment and the proof stress value YSB after the heat treatment when the heat treatment is performed for 10 minutes at a certain temperature on the plate. A method for producing an aluminum alloy plate for a lithographic printing plate, wherein the difference in the above is ΔYSB (= YSO−YSB), and the heat treatment temperature that satisfies the following formula (1) is 240 ° C. or higher.
ΔYSB ≧ ΔYSA × 1/2 (1) Fe 0.1-0.5%, Si 0.01-0.20%, Cu 0.005-0.07%, Mg 0.10-0.25%, Ti 0.003-0.03%, Zr 0.0005% or more Less than 0.004%, 0.001% to 0.01% Mn, 0.001% to 0.01% Zn, the balance being Al and inevitable impurities made of an aluminum alloy, hot against the ingot In rolling, the reduction amount in the final rolling pass is 3 mm or more, the hot rolling up temperature is in the range of 280 to 360 ° C., and the hot rolling up plate thickness is in the range of 1.0 to 4.0 mm. The obtained hot-rolled sheet is then cold-rolled to a product sheet thickness without intermediate annealing, and the average length of crystal grains in the direction perpendicular to the rolling direction is 100 μm or less and single Si The amount is 0.02% or less, and The difference between the proof stress value YSO before heating and the proof stress value YSA after heating when heated at 00 ° C. for 10 minutes is ΔYSA (= YSO−YSA), and heat treatment is performed for 10 minutes at the temperature on the plate. The difference between the proof stress value YSO before heat treatment and the proof stress value YSB after heat treatment is ΔYSB (= YSO−YSB), and the heat treatment temperature satisfying the following formula (1) is 240 ° C. or higher. The manufacturing method of the aluminum alloy plate for lithographic printing plates.
ΔYSB ≧ ΔYSA × 1/2 (1)