JP2007062217A - Support for lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the support for a lithographic printing plate employing an aluminum alloy plate obtained by continuous casting, which is manufactured inexpensively in a short period of time, has a uniform surface appearance, and, at the same time, to which uniform electrolytic surface roughening is applied. <P>SOLUTION: This support for the lithographic printing plate is obtained by applying at least surface roughening including electrochemical surface roughening with a nitric acid-containing aqueous solution to the aluminum alloy plate, which includes 0.10-0.40 mass% of Fe, 0.03-0.12 mass% of Si, ≤0.003 mass% of Cu, 0.001-0.02 mass% of Ti and the remainder of Al and unavoidable impurities, is cast by the continuous casting and obtained by applying cold rolling, intermediate annealing ranging from 280°C to 490°C and finishing cold rolling in the order named, under the condition that the nitric acid concentration of the aqueous solution is set to be ≤10 g/L. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate support using an aluminum alloy plate cast by a continuous casting method.

Photosensitive lithographic printing plate precursors widely used for offset printing are generally subjected to various surface treatments such as electrochemical roughening treatment on aluminum alloy plates (rolled plates) with a thickness of 0.1 to 0.5 mm. A lithographic printing plate support obtained by application is used.
As an aluminum material used for the aluminum alloy plate, a JIS1000 material or a JIS3000 material is often used. Regarding the composition of the aluminum material, the present inventor proposed a method for ensuring the uniformity of the electrochemical surface roughening treatment (electrolytic surface roughening treatment) using a material having an aluminum purity of 99.7% by mass or more. (See Patent Document 1). In addition to the composition of the aluminum material, the present inventors have also proposed a method for improving the uniformity of the electrolytic surface roughening treatment by defining the annealing conditions in the production process of the aluminum alloy plate (for example, (See Patent Documents 2 to 4.)

As a method for producing an aluminum alloy sheet, a slab obtained by casting a molten aluminum alloy (hereinafter also referred to as “Al molten metal”) by a semi-continuous casting method is subjected to homogenization heat treatment, hot rolling, cold rolling, and as necessary. A method for obtaining an aluminum alloy sheet by annealing is generally employed. On the other hand, various continuous casting methods have been proposed in which an aluminum alloy plate is directly cast into a plate shape using a driving mold for the purpose of continuously producing an aluminum alloy plate in a simpler process.
As a continuous casting method using such a driving mold, for example, a method using a pair of belt-shaped driving molds typified by the Husley method, or a method using a pair of roll-shaped driving molds typified by the Hunter method and the 3C method It has been known. The Hunter method is a method in which a pair of cooling rolls are disposed at an angle of about 15 ° from the vertical direction, and an aluminum alloy plate is cast obliquely upward. The 3C method is a method in which a pair of cooling rolls are arranged vertically and an aluminum alloy plate is cast in the horizontal direction.
The continuous casting method using these driving molds has the advantage that the equipment can be made compact and the investment cost is low. Among them, the method using a roll-shaped drive mold is excellent in that respect.

  In the method using a roll-shaped driving mold, molten Al is supplied between a pair of cooling rolls via a molten metal supply nozzle, and solidification and rolling of the molten Al are performed in one step by the cooling roll. Specifically, the method using a roll-shaped drive mold is described in, for example, Patent Documents 5 to 10.

Japanese Patent No. 3148057 US Pat. No. 5,711,827 US Pat. No. 5,779,824 US Pat. No. 5,525,168 U.S. Pat. No. 2,790,216 Canadian Patent 619,491 Specification Japanese Patent Publication No.51-15968 JP 51-89827 A JP 58-209449 A JP-A-1-215441

The obtained cast plate is subjected to cold rolling for making it thin and intermediate annealing for making the crystal structure fine and adjusting the strength.
This intermediate annealing is effective for refining crystal grains continuously and at a high temperature for a short time. However, an apparatus (continuous annealing furnace) for continuously performing the intermediate annealing is generally large and has high equipment costs. Therefore, when the intermediate annealing equipment is combined with continuous casting equipment, the equipment costs are low and the compact batch-type intermediate annealing equipment (batch) is used to take advantage of the compact equipment and low investment cost. In many cases, an annealing furnace is used.

However, when a batch type intermediate annealing apparatus is used, the crystal grains tend to be coarse. Moreover, it is known that the batch type intermediate annealing apparatus is inferior in the uniformity of the electrolytic surface roughening treatment.
On the other hand, the present inventor has proposed a method for improving the uniformity of the electrolytic surface roughening treatment by increasing the intermediate annealing temperature (see JP-A-8-92709). In order to achieve this, a batch-type intermediate annealing apparatus that can withstand many dynamic heat costs and high temperatures is required, and is not necessarily optimal in terms of cost.

  Further, as a method for producing a lithographic printing plate precursor, generally, a surface of a sheet-like or coil-like aluminum alloy plate is subjected to a roughening treatment and an anodizing treatment to obtain a lithographic printing plate support, There is known a method in which a photosensitive solution is applied on a support and dried to form an image recording layer, and if necessary, cut to a desired size. This lithographic printing plate precursor is subjected to a development process after image printing to form a lithographic printing plate.

In this method, in order to improve the adhesion between the image recording layer and the support, an electrolytic surface-roughening treatment in an acidic solution is effective, and after the anodizing treatment, a surface treatment or an undercoat solution is applied. It is also effective to do.
When the roughening treatment including the electrolytic roughening treatment is performed, minute irregularities (pits) are generated on the surface of the support. Conventionally, by making the diameter uniform and large, and by increasing the depth, the adhesion between the image recording layer and the support is strengthened in the image area. The recording layer does not peel off, and a large amount of fountain solution can be retained on the surface in the non-image area, so that a lithographic printing plate precursor excellent in printability can be obtained. It has been. For example, from such a viewpoint, it is effective to improve the shape and uniformity of the electrolytic roughening pits.
In addition, the surface of the lithographic printing plate precursor that is exposed and developed to become a non-image portion is exposed to the surface of the support that has been subjected to the roughening treatment and anodizing treatment, so that the uniformity of the appearance of the support surface is also provided. It becomes extremely important.

  Therefore, the present invention is a lithographic printing plate support using an aluminum alloy plate obtained by a continuous casting method, can be manufactured at a low cost in a short time, the surface appearance is uniform, and A first object is to provide a lithographic printing plate support that has been subjected to a uniform electrolytic surface-roughening treatment.

  In addition, the lithographic printing plate precursor is subjected to exposure and development to form a lithographic printing plate, which is then attached to a printing machine and used for printing. Nowadays, exposure, development and attachment to a printing machine are automatically performed. In many cases, conveyance is performed automatically between the exposure machine and the developing machine and between the developing machine and the printing machine. At that time, it is an essential condition that the lithographic printing plate precursor and the lithographic printing plate are reliably conveyed. If transport is not performed reliably, printing productivity will be adversely affected.

In addition, the planographic printing plate precursor is usually stored in a stacked state with paper called interleaving paper sandwiched between them in order to protect the image recording layer. In order to automatically transport the lithographic printing plate precursor to the exposure machine, it is necessary to reliably separate the slip sheet and the lithographic printing plate precursor. Adversely affect printing productivity.
Specifically, the slip sheet on the lithographic printing plate precursor is first removed by suction with a slip sheet adsorption-type removal device, and then the lithographic printing plate precursor below is placed in the exposure device with a suction cup type transport device. However, there is a possibility that the next slip sheet under the planographic printing plate precursor is transported together. This is because, when air is difficult to enter between the back side of the lithographic printing plate precursor and the next slip sheet during transport, the slip sheet is transported by adhering to the back surface of the lithographic printing plate precursor.

  Further, when the aluminum alloy plate is manufactured by the continuous casting method, there is a problem that it is difficult to control the cross-sectional profile of the plate being manufactured, compared to the conventional DC casting method and hot rolling method. Insufficient control of the cross-sectional profile of the plate will result in insufficient control of the thickness in the direction perpendicular to the rolling direction of the plate (hereinafter also referred to as the “width direction”). As a result, the aluminum alloy plate is conveyed by nip rolls. May cause a conveyance failure.

  In addition, when producing a lithographic printing plate precursor using an aluminum alloy plate obtained by a continuous casting method by an existing production facility for producing a lithographic printing plate precursor using an aluminum alloy plate obtained by a DC casting method, Since the cross-sectional profiles of the aluminum alloy plates are different, it may cause a conveyance failure. Specifically, the aluminum alloy plate obtained by the DC casting method has a thick center in the width direction, whereas the aluminum alloy plate obtained by the continuous casting method is flat in the width direction or in the width direction. Since the center is thin, it may cause a conveyance failure when conveyed by a nip roll.

  Accordingly, the present invention is a lithographic printing plate support using an aluminum alloy plate obtained by a continuous casting method, and is excellent in transportability and interleaf separation when used as a lithographic printing plate precursor or a lithographic printing plate. A second object is to provide a lithographic printing plate support.

The present inventor sets the composition of the aluminum alloy plate cast by the continuous casting method to a specific range, sets the temperature of the intermediate annealing to 280 to 490 ° C., and further applies a roughening treatment to the aluminum alloy plate. By applying an electrochemical surface roughening treatment using a nitric acid aqueous solution having a nitric acid concentration of 10 g / L or less, it can be manufactured at a low cost in a short time, and the surface appearance is uniform and uniform electrolysis. The inventors found that a lithographic printing plate support having been subjected to a roughening treatment was obtained, and completed the lithographic printing plate support of the first aspect of the present invention.
Further, the inventor sets the composition of the aluminum alloy plate cast by the continuous casting method to a specific range, sets the temperature of the intermediate annealing to 280 to 490 ° C., and further subjects the aluminum alloy plate to a roughening treatment. In this case, the surface opposite to the surface subjected to the roughening treatment (that is, the back surface) is subjected to an alkali etching treatment with an aluminum dissolution amount of 1 to 10 g / m ² , and in the rolling direction and the width direction of the back surface. By making the average surface roughness within a specific range, it has been found that a lithographic printing plate support having excellent transportability and interleaf separation when obtained as a lithographic printing plate precursor or a lithographic printing plate can be obtained. The lithographic printing plate support of the second aspect was completed.

That is, the present invention provides the following (1) to (5).
(1) Fe: 0.10 to 0.40 mass%, Si: 0.03 to 0.12 mass%, Cu: 0.003 mass% or less, Ti: 0.001 to 0.02 mass% The balance is made of Al and unavoidable impurities, and is cast by a continuous casting method.In the aluminum alloy plate obtained by performing cold rolling, intermediate annealing at a temperature of 280 to 490 ° C., and finish cold rolling in this order, At least a support for a lithographic printing plate obtained by performing a surface roughening treatment including an electrochemical surface roughening treatment using an aqueous solution containing nitric acid,
A lithographic printing plate support (the lithographic printing plate support according to the first aspect of the present invention), wherein the aqueous solution has a nitric acid concentration of 10 g / L or less.
(2) The said aluminum alloy plate is Fe: 0.10-0.20 mass%, Si: 0.03-0.06 mass%, Cu: 0.003 mass% or less, Ti: 0.001-0. The lithographic printing plate support according to (1) above, comprising 02% by mass, the balance comprising Al and inevitable impurities.
(3) The said aluminum alloy plate is Fe: 0.24-0.36 mass%, Si: 0.06-0.10 mass%, Cu: 0.003 mass% or less, Ti: 0.001-0. The lithographic printing plate support according to (1) above, comprising 02% by mass, the balance comprising Al and inevitable impurities.
(4) Fe: 0.10-0.40 mass%, Si: 0.03-0.12 mass%, Cu: 0.003% or less, Ti: 0.001-0.02 mass% The balance is made of Al and unavoidable impurities, and is cast by a continuous casting method.In the aluminum alloy plate obtained by performing cold rolling, intermediate annealing at a temperature of 280 to 490 ° C., and finish cold rolling in this order, At least a support for a lithographic printing plate obtained by subjecting to a roughening treatment,
The surface of the aluminum alloy plate opposite to the surface subjected to the roughening treatment is subjected to an alkali etching treatment with an aluminum dissolution amount of 1 to 10 g / m ² and an average surface roughness in the rolling direction. R _a is 0.15 to 0.35, an average surface roughness in the direction perpendicular to the rolling direction R _a is 0.20 to 0.40, the lithographic printing plate support (second of the present invention A support for a lithographic printing plate of an embodiment).
(5) On the surface of the aluminum alloy plate opposite to the surface subjected to the roughening treatment, a plurality of ridges having substantially equal intervals are formed in a direction perpendicular to the rolling direction. The support for a lithographic printing plate as described in (4) above, wherein the interval between the ridges is in the range of 3 to 10 mm.

The lithographic printing plate support according to the first aspect of the present invention is a lithographic printing plate support using an aluminum alloy plate obtained by a continuous casting method, and can be produced at low cost in a short time. The surface appearance is uniform, and a uniform electrolytic surface roughening treatment is applied.
The lithographic printing plate support according to the second aspect of the present invention is a lithographic printing plate support using an aluminum alloy plate obtained by a continuous casting method, and includes a lithographic printing plate precursor and a lithographic printing plate. It has excellent transportability and interleaf separation.

  Hereinafter, the lithographic printing plate support according to the first aspect of the present invention and the lithographic printing plate support according to the second aspect (hereinafter, both are also referred to as the “lithographic printing plate support according to the present invention”). Will be described in detail. In the present invention, a support for a lithographic printing plate corresponding to both the first aspect and the second aspect is preferable.

[Support for lithographic printing plate]
<Aluminum alloy plate>
The aluminum alloy plate (hereinafter also simply referred to as “aluminum plate”) used for the lithographic printing plate support of the present invention is Fe: 0.10 to 0.40 mass%, Si: 0.03 to 0.12. Cu: 0.003% by mass or less, Cu: 0.001 to 0.02% by mass, the balance is made of Al and inevitable impurities, cast by a continuous casting method, cold rolling, temperature It is an aluminum alloy plate obtained by performing intermediate annealing at 280 to 490 ° C. and cold rolling in this order.

<Composition>
Si is an element contained as an inevitable impurity in an Al ingot, which is a raw material, in an amount of about 0.03 to 0.1% by mass, and is often intentionally added in a small amount to prevent variation due to a difference in raw materials. Si exists as a solid solution in aluminum, or as an intermetallic compound or a single precipitate.
In the present invention, the amount of Si is 0.03 to 0.12% by mass.

Fe has an effect of increasing the mechanical strength of the aluminum alloy, and greatly affects the strength of the support. In particular, it is preferably added intentionally because it has a great effect of improving heat-softening resistance.
If the Fe content is too small, the mechanical strength is too low, and it becomes easy to cause plate breakage when a lithographic printing plate is attached to a plate cylinder of a printing press. Further, when printing a large number of copies at high speed, the plate is likely to be cut out similarly. On the other hand, when the Fe content is too high, the strength becomes higher than necessary, and when the lithographic printing plate is attached to the plate cylinder of a printing press, the fitness is inferior, and the plate is easily cut during printing. Moreover, when there is too much content of Fe, it will become easy to produce a crack in the middle of rolling.
Fe has a small amount of solid solution in aluminum, and most of it exists as an intermetallic compound.
In the present invention, the amount of Fe is 0.10 to 0.40 mass%.

In the aluminum alloy plate used in the present invention, Fe: 0.10 to 0.40 mass%, Si: 0.03 to 0.12 mass%, and among them, Fe: 0.10 to 0.20 mass% %, Si: 0.03-0.06% by mass, and Fe: 0.24-0.36% by mass, Si: 0.06-0.10% by mass.
When the combination of the amount of Fe and the amount of Si is one of the above two combinations, the electrolytic surface roughening treatment is performed uniformly. In particular, the mass ratio of Fe to Si (Fe / Si) is preferably in the range of 3-4. The reason for this is not clear, but Fe and Si may become intermetallic compounds. In particular, when manufactured by a continuous casting method, a compound of Fe and Si (for example, α-AlFeSi, β-AlFeSi) is formed. This is considered to be caused by an increase or decrease in the amount of Fe and Si that dissolve relatively. In particular, as the amount of Fe and Si compounds increases, the amount of dissolved Si decreases, and as a result, the pit generation potential decreases, particularly during electrochemical surface roughening using an aqueous solution containing nitric acid, It is considered that the pit formation start points on the surface are excessively increased, adjacent pits are integrated, and it becomes difficult to form independent substantially hemispherical pits. Similarly, part of Fe forms a compound with the above-mentioned Si according to the addition amount, and the rest exists as a solid solution in Al or as an intermetallic compound. When the solid solution amount of Fe is small, the uniformity of the electrolytic surface roughening treatment is lowered as in the case of Si. The reason why it is preferable in the region where the amount of Fe is 0.10 to 0.20% by mass and two regions of 0.24 to 0.36% by mass is not clear, but the amount of Fe solid solution that increases or decreases depending on the total amount added However, it is considered that in these two regions, combined with the above-described solid solution amount of Si, there is an effect of improving the uniformity of the electrolytic surface roughening treatment. The surface quality can be improved by improving the uniformity of the electrolytic surface roughening treatment.

Cu is an important element in controlling the electrolytic surface roughening treatment. Cu is an element that is very easily dissolved, and part of it is an intermetallic compound.
In the present invention, it is preferable to produce small and uniform pits during the electrolytic surface roughening treatment, so Cu is made 0.003 mass% or less.
The lower limit of the amount of Cu is not particularly limited, but high-purity Al ingots are expensive. From the viewpoint of the cost of Al ingots, 0.0001% by mass or more is preferable.

The aluminum alloy plate contains 0.001 to 0.02% by mass of Ti, which is an element for refining crystal grains, in order to prevent cracking during casting.
Further, since B is preferably added as a compound with Ti as a crystal grain refining material, the aluminum alloy plate can contain B in a range of 0.0002 to 0.005 mass%. B does not affect the electrolytic roughening property.

Even if Ti and B are added separately, there is an effect of refining the crystal grains. However, TiB ₂ which is a compound of Ti and B becomes a nucleus of crystal growth, so when there are many TiB ₂ particles, Since many crystal nuclei are formed and many fine crystals are present as a result, surface treatment unevenness caused by coarse crystal grains is suppressed in surface treatment when making a lithographic printing plate support. can do. Therefore, it is preferable to add TiB ₂ . The mother alloy containing TiB _2, for example, Ti (5 wt%) - B (1 wt%), the balance wire-like mother alloy consisting of Al and unavoidable impurities and the like typically.

TiB ₂ alone is usually very small particles of 1 to 2 μm, but sometimes aggregates to become coarse particles of 100 μm or more, and in that case, the coarse particles cause surface treatment unevenness. Therefore, it is preferable to provide a stirring means in the filtration step and / or the supply step described later.

The balance of the aluminum alloy plate is made of Al and inevitable impurities. Examples of inevitable impurities include Mg, Mn, Zn, Cr, Zr, V, Zn, and Be. These can each be contained in a range of 0.05% by mass or less.
Most of the inevitable impurities are contained in the Al ingot. If the inevitable impurities are contained in, for example, a metal having an Al purity of 99.7% by mass, the effects of the present invention are not impaired. For inevitable impurities, see, for example, F. The amount of impurities described in Mondolfo's “Aluminum Alloys: Structure properties” (1976) and the like may be contained.

<Continuous casting>
The aluminum alloy plate containing the above-described components used in the present invention is cast from a molten Al containing the above-described components by a continuous casting method.
As the continuous casting method, a twin roll method (hunter method), a method using a cooling roll typified by the 3C method, a twin belt method (Hazley method), a cooling belt or a cooling block typified by Al-Swiss Caster II type is used. The method is carried out industrially. When the continuous casting method is used, it solidifies at a cooling rate of 100 to 1000 ° C./second. Since the continuous casting method generally has a higher cooling rate than the DC casting method, the solid solubility of the alloy components in the aluminum matrix can be increased.
Regarding the continuous casting method, the techniques proposed by the applicant of the present application are disclosed in JP-A-3-79798, JP-A-5-201166, JP-A-5-156414, JP-A-6-262203, and JP-A-6-122949. JP-A-6-210406 and JP-A-6-26308. In the present invention, these methods can be used.

  When continuous casting is performed, for example, if a method using a cooling roll such as a Hunter method is used, a cast plate having a thickness of 1 to 10 mm can be directly cast continuously, and the hot rolling step is omitted. The advantage of being able to In addition, when a method using a cooling belt such as the Husley method is used, a cast plate having a thickness of 10 to 50 mm can be cast. Generally, a hot rolling roll is arranged immediately after casting and continuously rolled. Thus, a continuous cast and rolled plate having a thickness of 1 to 10 mm is obtained.

  Hereinafter, as an example of the continuous casting method, molten aluminum is supplied between a pair of cooling rolls via a molten metal supply nozzle, and the aluminum alloy sheet is rolled by solidifying the molten aluminum alloy by the pair of cooling rolls. A specific description will be given by taking a method of forming.

<Cleaning process>
Prior to the continuous casting step, the Al molten metal prepared to contain the above-described components can be subjected to a cleaning treatment. Examples of the cleaning treatment include flux treatment, degassing treatment using argon gas, chlorine gas, etc. in order to remove unnecessary gas such as hydrogen in the molten Al. The cleaning treatment can be performed according to a conventional method.
The cleaning treatment is not essential, but is preferably performed to prevent defects due to foreign matters such as non-metallic inclusions and oxides in the molten Al and defects due to gas dissolved in the molten Al.

  Regarding filtering of the molten metal, JP-A-6-57432, JP-A-3-162530, JP-A-5-140659, JP-A-4-231425, JP-A-4-276031, JP-A-5-312661 and JP-A-5-311261 are disclosed. 6-136466 and the like. Further, the degassing of the molten metal is described in JP-A-5-51659, Japanese Utility Model Laid-Open No. 5-49148, and the like. The applicant of the present application has also proposed a technique relating to degassing of molten metal in Japanese Patent Application Laid-Open No. 7-40017. In the present invention, these methods can be used.

<Crystal grain refinement process>
Ti and / or B can be dissolved in a melting furnace, but it is preferable to add a master alloy containing TiB ₂ in a flow path downstream from the melting furnace.

<Filtration process>
Prior to the continuous casting step, it is preferable to perform a filtration step of filtering the molten Al using a filter tank. Thereby, impurities mixed in the Al molten metal, contaminants remaining in the melting furnace, the molten metal flow path, and the like can be removed. Moreover, the outflow of the coarse particles of TiB ₂ described above can also be suppressed. For this purpose, it is preferable to dispose the filter tank downstream from the position where TiB ₂ is added to the molten Al.
About a filtration process and the filter tank used for it, what is described in patent 3549080 is preferable.

<Supply process>
In the present invention, a supply step of supplying the molten aluminum alloy after the filtration step to the molten metal supply nozzle from the filter tank via the flow channel is performed, and the supply step is formed on the bottom surface of the flow channel. It is preferable that the stirring means provided in the recess stir the molten aluminum alloy. This prevents the coarse particles of TiB _{2 from} aggregating again at the stagnation part of the molten metal after passing through the filtration step.

<Melting nozzle>
The Al molten metal discharged from the molten metal supply nozzle comes into contact with the surface of the cooling roll and starts to solidify. Here, when the molten Al moves from the tip of the molten metal supply nozzle to the surface of the cooling roll, a meniscus of the molten Al is formed. When this meniscus vibrates, the contact point with the cooling roll vibrates, and as a result, a portion having a different solidification history is generated on the surface, and the crystal structure is uneven and segregation of trace elements is likely to occur. This failure is called a ripple mark, and when subjected to cold rolling, intermediate annealing and finish cold rolling, surface treatment as a lithographic printing plate support tends to cause surface treatment unevenness.
On the other hand, when the tip end of the nozzle has an acute angle with respect to the discharge direction of the molten metal, at least one position where the Al molten metal detaches from the tip of the nozzle. It is preferable because the ripple mark can be reduced. For example, the method described in JP-A-10-58094 can be preferably used.

In order to reduce the amplitude when the meniscus vibrates, it is preferable to reduce the distance between the tip of the nozzle and the surface of the cooling roll. Therefore, ideally, the tip of the nozzle and the surface of the cooling roll are always in contact with each other, the angle of the lower (preferably lower and upper) outer surfaces described above being acute with respect to the discharge direction of the molten metal. The state which is carrying out is preferable.
Specifically, for example, among the members constituting the molten metal supply nozzle, the upper plate member that comes into contact with the Al molten metal from the upper surface and the lower plate member that comes into contact with the Al molten metal from the lower surface are respectively movable in the vertical direction. Preferably, an embodiment in which the upper plate member and the lower plate member are respectively pressed by the pressure of the Al molten metal and pressed against the surface of the adjacent cooling roll is preferable. For example, the mode described in JP 2000-117402 A can be suitably used.
As a result, the tip of the molten metal supply nozzle is always in contact with the cooling roll, and as a result, the shape of the molten metal meniscus is maintained in a constant state. You can get a body.

Even if the meniscus of the molten Al is stabilized in this way, if the flow of the molten Al in the molten metal supply nozzle is not uniform, the continuously cast aluminum alloy plate tends to be nonuniform. Therefore, it is necessary to make the molten metal flow uniform in the molten metal supply nozzle. However, since the gap between the pair of cooling rolls is as small as several mm to 10 mm, the nozzle that supplies the molten metal to the thin nozzle also has a very thin structure. Thus, the space through which the molten Al inside the nozzle passes is also narrowed. Therefore, the stagnation of the Al molten metal in the nozzle immediately leads to non-uniform Al molten metal flow.
In order to prevent stagnation of the Al melt inside the nozzle, the pre-melt supply nozzle has a median diameter of 5 to 20 μm and a mode diameter of 4 to 12 μm in advance on the inner surface in contact with the Al melt. It is preferable to apply a release agent containing aggregate particles. Examples of the release agent that does not easily cause stagnation of the molten Al include a release agent that uses zinc oxide, boron nitride (BN), or the like as an aggregate. Among these, a release agent using boron nitride as an aggregate is preferable. For example, the method described in JP-A-11-192537 can be preferably used.

<Cooling roll>
A cooling roll is not specifically limited, For example, conventionally well-known things, such as a cooling roll of iron core-shell structure, can be used. When using a core-shell structured cooling roll, the cooling capacity of the surface of the cooling roll can be increased by passing cooling water through a channel provided between the core and shell. Further, by further reducing the solidified aluminum, the thickness of the aluminum alloy plate can be accurately adjusted to a desired thickness.
If the aluminum solidified on the surface of the chill roll is left as it is, it may be easily fixed to the chill roll, and it may not be easy to cast stably and continuously. Therefore, in the present invention, it is preferable that a release agent is applied to the surface of the pair of cooling rolls. As a mold release agent, what is excellent in heat resistance is preferable, For example, what contains carbon graphite is mentioned suitably. The method of application is not particularly limited, and for example, a method of spray-coating a suspension of carbon graphite particles (preferably an aqueous suspension) is preferable. Spray coating is preferred because it can supply the release agent to the cooling roll in a non-contact manner.

Here, if the thickness of the applied release agent is different in the width direction and / or the circumferential direction of the cooling roll, it affects the speed of heat transfer to the cooling roll and leads to nonuniform crystal grains. In the present invention, it is preferable to make the thickness of the applied release agent uniform.
Specifically, for example, a method in which a wiper made of a refractory material or a heat-resistant cloth is brought into contact with the surface of the cooling roll at a constant pressure is preferable. Further, when there is no risk of direct contact with the molten metal, a cloth such as cotton can be used to make it uniform.

  Moreover, since the mold release agent is captured by a uniformizing means such as a wiper or moved to the surface of a continuously cast aluminum alloy plate, it is preferable to periodically supply it to the surface of the cooling roll.

Further, when the molten metal supply nozzle contacts the cooling roll in the width direction unevenly, the release agent on the surface of the cooling roll is partially scraped off, resulting in an inadequate thickness of the release agent on the roll surface. It tends to be uniform, and in turn tends to make crystal grains non-uniform. The non-uniformity of the crystal grains leads to streaky appearance failure such as streak when the planographic printing plate support is used.
Therefore, in the present invention, it is preferable that the outer edge of the mouth of the molten metal supply nozzle does not contact the cooling roll or contacts only at the tip thereof.

<Cold rolling process>
A cold rolling process is performed after a continuous casting process. The cold rolling process is a process of reducing the thickness of the aluminum alloy plate obtained in the continuous casting process. Thereby, an aluminum alloy plate is made into desired thickness.
The cold rolling process can be performed by a conventionally known method.

<Intermediate annealing process>
After the cold rolling step, an intermediate annealing step is performed. The intermediate annealing step is a step of performing a heat treatment on the aluminum alloy plate in the cold rolling step.
Originally, the continuous casting process can cool and solidify aluminum very rapidly, unlike the conventional method using a fixed mold. As a result, the crystal grains in the aluminum alloy plate obtained through continuous casting can be remarkably refined as compared with the conventional method using a fixed mold. However, as it is, the size of the crystal grains is still large, and after the finish cold rolling, when the surface of the lithographic printing plate is further subjected to a roughening treatment, the appearance failure due to the size of the crystal grains (surface Uneven processing) is likely to occur.
Therefore, after accumulating processing strain in the cold rolling process described above, by performing the intermediate annealing process, the dislocation accumulated in the cold rolling process is released, recrystallization occurs, and the crystal grains are further refined Will be able to. Specifically, the crystal grains can be controlled by the processing rate in the cold rolling process and the heat treatment conditions in the intermediate annealing process (in particular, the temperature, time, and heating rate).

In the present invention, intermediate annealing is performed at 280 to 490 ° C. Thereby, refinement | miniaturization of a crystal grain can be accelerated | stimulated and by extension generation | occurrence | production of the appearance failure (surface treatment nonuniformity) resulting from the magnitude | size of a crystal grain can be suppressed.
The intermediate annealing time is preferably 5 to 40 hours.
The temperature raising rate of the intermediate annealing is preferably 1 to 60 ° C./min.
In the present invention, a batch type annealing furnace can be used, and a continuous annealing furnace can also be used. A batch-type annealing furnace is preferable in that the equipment cost is low and it is compact.

<Finish cold rolling process>
A finishing cold rolling process is performed after an intermediate annealing process. The finish cold rolling step is a step of reducing the thickness of the aluminum alloy sheet after the intermediate annealing. The thickness after the finish cold rolling step is preferably 0.1 to 0.5 mm.
The cold rolling process can be performed by a conventionally known method. For example, it can be performed by the same method as the cold rolling step performed before the intermediate annealing step described above.

Here, in the present invention, in the finish cold rolling, the distance in the width direction is almost in the range of 3 to 10 mm by the method of making the lubricant less than the standard amount or the method of making the reduction ratio 80% or more. A plurality of ridges with equal intervals (hereinafter also referred to as “equal pitch pattern”) can be formed. This protrusion (chattering) is about 1% of the plate thickness at the maximum, and looks like a pattern.
During the production of a lithographic printing plate support, by carrying out an alkali etching treatment, the surface of the surface opposite to the surface on which the roughening treatment is performed and the image recording layer is provided is made to manifest this protrusion, and the transportability In addition, a lithographic printing plate precursor having excellent slip sheet separation can be obtained.

<Flatness correction process>
In the present invention, it is preferable to perform the flatness correction step after the finish cold rolling step and before the roughening treatment step. The flatness correcting step is a step of correcting the flatness of the aluminum alloy plate.
The flatness correction step can be performed by a conventionally known method. For example, it can be performed using a correction device such as a roller leveler or a tension leveler.
The flatness correction step may be performed after the aluminum alloy plate is cut into a sheet shape, but it is preferably performed in a continuous coil state in order to improve productivity.

<Slit process>
Moreover, in order to process the plate width into a predetermined width, a slitting process through a slitter line can be performed. A slit process can be performed by a conventionally well-known method.

<Oil film formation process>
Moreover, in order to prevent generation | occurrence | production of the damage | wound by friction between aluminum alloy plates, a thin oil film can be provided on the surface of an aluminum alloy plate. The oil used for the oil film may be volatile or non-volatile, and can be appropriately selected and used.

<Refining process>
The aluminum alloy plate used in the present invention is preferably subjected to H18 tempering as defined in JIS.

<Properties>
The aluminum alloy plate used in the present invention preferably has an average crystal grain width of 50 to 150 μm and an average length of 300 to 900 μm.
Within the above range, even if a batch-type annealing furnace in which crystal grains tend to be large is used, uneven surface quality is unlikely to occur.

  The aluminum alloy plate used in the present invention preferably has a tensile strength of 140 to 160 MPa. Within the above range, it is difficult for plate breakage to occur during printing.

The aluminum alloy plate used in the present invention preferably has a 0.2% proof stress of 100 to 120 MPa after being held at 270 ° C. for 7 minutes.
If it is within the above range, it is usually attached to the plate cylinder because the rigidity of the lithographic printing plate precursor for bending is moderate even after performing a burning treatment which is often performed at 200 ° C. or more, particularly around 240 to 270 ° C. Can be bent without problems. Therefore, it is difficult for plate breakage to occur during printing.
In the present invention, “0.2% yield strength” refers to a load when the permanent elongation is 0.2% in a tensile test. For example, it can be determined according to the provisions of JIS Z2241-1993.
Heating is performed using an apparatus that can uniformly heat the entire surface. Examples of such a heating device include a radiant heating device. Specifically, a PLANO PS burning processor 1300 manufactured by Fuji Photo Film Co., Ltd. can be cited as a radiant heating device.

<Roughening treatment>
The lithographic printing plate support of the first aspect of the present invention is obtained by subjecting the above-described aluminum alloy plate to a surface roughening treatment including an electrochemical surface roughening treatment using an aqueous solution containing at least nitric acid. It is done.
The lithographic printing plate support according to the second aspect of the present invention is obtained by subjecting the above-described aluminum alloy plate to at least a roughening treatment.
In the production of the lithographic printing plate support of the present invention, various steps other than those described above may be included. For example, an electrochemical surface roughening treatment in an aqueous solution containing nitric acid or hydrochloric acid, an etching treatment in an alkaline aqueous solution, a desmut treatment in an acidic aqueous solution, or the like may be included once or a plurality of times.

Specifically, for example, etching treatment in an alkaline aqueous solution (hereinafter also referred to as “first alkaline etching treatment”), desmutting treatment in an acidic aqueous solution (hereinafter also referred to as “first desmutting treatment”), nitric acid or Electrochemical roughening treatment in an aqueous solution containing hydrochloric acid (hereinafter also referred to as “first electrochemical roughening treatment”), etching treatment in an alkaline aqueous solution (hereinafter referred to as “second alkaline etching treatment”). And a method of performing desmutting treatment in an acidic aqueous solution (hereinafter also referred to as “second desmutting treatment”) and anodizing treatment in this order.
In addition, for example, a first alkali etching treatment, a first desmutting treatment, a first electrochemical roughening treatment, a second alkali etching treatment, a second desmutting treatment, and an electrochemical roughening in an aqueous solution containing hydrochloric acid. Treatment (hereinafter also referred to as “second electrochemical roughening treatment”), etching treatment in an alkaline aqueous solution (hereinafter also referred to as “third alkaline etching treatment”), desmutting treatment in an acidic aqueous solution (hereinafter referred to as “second electrochemical etching treatment”). A method of performing the third desmut treatment ”) and anodizing treatment in this order is preferable.
Further, after the anodizing treatment, a sealing treatment, a hydrophilization treatment, or a sealing treatment and a subsequent hydrophilization treatment are also preferable.
Moreover, a mechanical surface roughening process can also be performed before a 1st alkali etching process. Thereby, the amount of electricity used for the first electrochemical surface roughening treatment can be reduced.

  Hereinafter, each step of the surface treatment will be described in detail.

<Mechanical roughening>
Examples of the mechanical surface roughening treatment include, for example, a wire brush grain method in which the aluminum surface is scratched with a metal wire, a ball grain method in which the aluminum surface is grained with a polishing ball and an abrasive, JP-A-6-135175 and JP-B-50. The brush grain method in which the surface is grained with a nylon brush and an abrasive described in Japanese Patent No. 40047 can be used.
Moreover, the transfer method (transfer roll method) which press-contacts an uneven surface to an aluminum plate can also be used. That is, in addition to the methods described in JP-A-55-74898, JP-A-60-36195, and JP-A-60-20396, transfer is performed several times. The method described in JP-A-6-24168 and JP-A-6-24168 characterized in that the surface is elastic is also applicable.
Among these, the transfer roll method is preferable because it can easily cope with the speedup of the manufacturing process of the support for a lithographic printing plate. As described above, the transfer roll method preferably performs the transfer in the cold rolling for adjusting to the final plate thickness or the finish cold rolling for finishing the surface shape after the final plate thickness adjustment.

Hereinafter, the brush grain method used as the mechanical surface roughening process will be described.
The brush grain method generally uses a roller-shaped brush in which a large number of brush hairs such as synthetic resin hair made of synthetic resin such as nylon (trade name), propylene, and vinyl chloride resin are implanted on the surface of a cylindrical body. In this method, the surface is roughened by rubbing one or both of the surfaces of the aluminum plate while spraying a slurry liquid containing an abrasive on a rotating roller brush. Instead of the roller brush and the slurry liquid, a polishing roller which is a roller having a polishing layer on the surface can be used.

When using a roller-like brush, the flexural modulus is preferably 10,000 to 40,000 kgf / cm ² , more preferably 15,000 to 35,000 kgf / cm ² , and the bristle strength is preferably Brush hair of 500 gf or less, more preferably 400 gf or less is used. The diameter of the brush bristles is generally 0.2 to 0.9 mm. The length of the brush bristles can be appropriately determined according to the outer diameter of the roller brush and the diameter of the trunk, but is generally 10 to 100 mm.
In the present invention, it is preferable to use a plurality of brushes, specifically, 3 or more are preferable, and 4 or more are more preferable. By adjusting the number of brushes, the wavelength component of the recesses formed on the aluminum plate surface can be adjusted.

  The load of the drive motor that rotates the brush is preferably 1 kW plus or more, more preferably 2 kW plus or more, and even more preferably 8 kW plus or more with respect to the load before the brush roller is pressed against the aluminum plate. By adjusting the load, the depth of the recess formed on the aluminum plate surface can be adjusted. The rotation number of the brush is preferably 100 rotations or more, and more preferably 200 rotations or more.

A well-known thing can be used as a polishing agent. For example, abrasives such as pumice stone (pumice stone), silica sand, aluminum hydroxide, alumina powder, silicon carbide, silicon nitride, volcanic ash, carborundum, and gold sand; a mixture thereof can be used. Of these, pumiston and silica sand are preferable. Quartz sand is harder and less fragile than Pamiston, so it has excellent roughening efficiency. In addition, aluminum hydroxide is suitable when an excessive load is applied and the particles are damaged, so that it is not desired to generate deep recesses locally.
The median diameter of the abrasive is preferably from 2 to 100 μm, more preferably from 20 to 60 μm, from the viewpoint of excellent surface roughening efficiency and the ability to narrow the graining pitch. By adjusting the median diameter of the abrasive, the depth of the recess formed on the aluminum plate surface can be adjusted.

For example, the abrasive is suspended in water and used as a slurry. In addition to the abrasive, the slurry liquid may contain a thickener, a dispersant (for example, a surfactant), a preservative, and the like. The specific gravity of the slurry liquid is preferably 0.5-2.
As an apparatus suitable for the mechanical surface roughening treatment, for example, an apparatus described in JP-B-50-40047 can be exemplified.

  As for details of an apparatus for performing a mechanical surface roughening process using a brush and an abrasive, for example, the one proposed by the applicant of the present application in Japanese Patent Application Laid-Open No. 2002-211159 can be used.

  In the present invention, an aluminum plate having a concavo-convex pattern formed on the surface by transfer may be used instead of a mechanical surface roughening treatment using a brush and an abrasive, or both surface roughening may be used in combination. Good.

<First alkali etching treatment>
An alkali etching process is a process which melt | dissolves a surface layer by making the aluminum plate mentioned above contact an alkaline solution.

The first alkali etching treatment performed before the first electrochemical roughening treatment was performed by forming a uniform recess in the first electrochemical roughening treatment and performing a mechanical roughening treatment. In this case, the uneven shape formed by the mechanical surface roughening treatment should be smoothed. If the mechanical surface roughening treatment was not performed, the rolling oil on the surface of the aluminum plate (rolled aluminum), dirt, It is performed for the purpose of removing a natural oxide film or the like.
In the first alkali etching treatment, the etching amount of the surface to be subjected to the electrochemical roughening treatment later is preferably 0.1 g / m ² or more, more preferably 0.5 g / m ² or more. more preferably, more preferably at 1 g / m ² or more, but preferably not more 10 g / m ² or less, more preferably at 8 g / m ² or less, further not less 5 g / m ² or less preferable. When the etching amount is 0.5 g / m ² or more, uniform pits can be generated in the first electrochemical surface roughening treatment, and the occurrence of processing unevenness can be prevented. When the etching amount is 10 g / m ² or less, the amount of alkaline aqueous solution used is reduced, which is economically advantageous.

The etching amount of the surface opposite to the surface subjected to the roughening treatment of the aluminum alloy plate is preferably 5% by mass or more of the etching amount of the surface subjected to the electrochemical roughening treatment. The content is more preferably at least mass%, more preferably at most 50 mass%, and even more preferably at most 30 mass%. It is excellent in the balance with the removal effect of the rolling oil of the back surface of an aluminum plate, and economical efficiency as it is the said range.
The same applies to a second alkali etching process and a third alkali etching process to be described later.

In the lithographic printing plate support according to the second aspect of the present invention, the etching amount of the surface (back surface) opposite to the surface to be roughened of the aluminum alloy plate is 1 to 10 g / m ² . is there. Thereby, the average surface roughness of a back surface can be made into the suitable range mentioned later.
In the lithographic printing plate support of the second aspect of the present invention, when the alkali etching treatment is performed a plurality of times, the total etching amount may be in the above range.

  Examples of the alkali used in the alkaline solution include caustic alkali and alkali metal salts. Specifically, examples of caustic alkali include caustic soda and caustic potash. Examples of the alkali metal salt include alkali metal silicates such as sodium metasilicate, sodium silicate, potassium metasilicate, and potassium silicate; alkali metal carbonates such as sodium carbonate and potassium carbonate; sodium aluminate and alumina. Alkali metal aluminates such as potassium acid; alkali metal aldones such as sodium gluconate and potassium gluconate; dibasic sodium phosphate, dibasic potassium phosphate, primary sodium phosphate, primary potassium phosphate, etc. An alkali metal hydrogen phosphate is mentioned. Among these, a caustic alkali solution and a solution containing both a caustic alkali and an alkali metal aluminate are preferable from the viewpoint of high etching rate and low cost. In particular, an aqueous solution of caustic soda is preferable.

In the first alkali etching treatment, the concentration of the alkaline solution is preferably 30 g / L or more, more preferably 300 g / L or more, and preferably 500 g / L or less, 450 g / L. The following is more preferable.
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 1 g / L or more, more preferably 50 g / L or more, and preferably 200 g / L or less, more preferably 150 g / L or less. Such an alkaline solution can be prepared using, for example, water, a 48 mass% sodium hydroxide aqueous solution, and sodium aluminate.

In the first alkali etching treatment, the temperature of the alkali solution is preferably 30 ° C. or higher, more preferably 50 ° C. or higher, and preferably 80 ° C. or lower, and 75 ° C. or lower. Is more preferable.
In the first alkaline etching treatment, the treatment time is preferably 1 second or longer, more preferably 2 seconds or longer, more preferably 30 seconds or shorter, and more preferably 15 seconds or shorter. preferable.

When the aluminum plate is continuously etched, the aluminum ion concentration in the alkaline solution increases and the etching amount of the aluminum plate varies. Therefore, the composition management of the etching solution is preferably performed as follows.
That is, a matrix of conductivity, specific gravity, and temperature, or a matrix of conductivity, ultrasonic propagation velocity, and temperature corresponding to the matrix of caustic soda concentration and aluminum ion concentration is prepared in advance, and the conductivity and specific gravity are prepared. The liquid composition is measured according to the temperature and temperature, or the electrical conductivity, the ultrasonic wave propagation speed, and the temperature, and caustic soda and water are added so that the control target value of the liquid composition is reached. Then, the amount of the etching solution increased by adding caustic soda and water is overflowed from the circulation tank, thereby keeping the amount of the solution constant. As caustic soda to be added, 40 to 60% by mass for industrial use can be used.
As the conductivity meter and the specific gravity meter, it is preferable to use those that are temperature-compensated. As the specific gravity meter, a differential pressure type is preferably used.

  Examples of the method of bringing the aluminum plate into contact with the alkaline solution include, for example, a method in which the aluminum plate is passed through a tank containing the alkaline solution, a method in which the aluminum plate is immersed in a tank containing the alkaline solution, The method of spraying on the surface of a board is mentioned.

  Among these, a method in which an alkali solution is sprayed on the surface of an aluminum plate is preferable. Specifically, a method of spraying an etching solution in an amount of 10 to 100 L / min per spray tube from a spray tube having φ2 to 5 mm holes at a pitch of 10 to 50 mm is preferable. It is preferable to provide a plurality of spray tubes.

After the alkali etching treatment is completed, it is preferable to drain the liquid with a nip roll, and further perform the water washing treatment for 1 to 10 seconds, and then drain the liquid with a nip roll.
The water washing treatment is preferably carried out using an apparatus for washing with a free-falling curtain-like liquid film, and further using a spray tube.

  Moreover, as a spray tube used for the water-washing process, for example, a spray tube having a plurality of spray tips in the width direction of the aluminum plate in which spray water spreads in a fan shape can be used. The distance between spray tips is preferably 20 to 100 mm, and the amount of liquid per spray tip is preferably 0.5 to 20 L / min. It is preferable to use a plurality of spray tubes.

<First desmut treatment>
After the first alkali etching treatment, it is preferable to perform pickling (first desmutting treatment) in order to remove dirt (smut) remaining on the surface. The desmut treatment is performed by bringing an aluminum plate into contact with an acidic solution.

  Examples of the acid used include nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid. Of these, nitric acid and sulfuric acid are preferable. Specifically, for example, an overflow waste solution of a nitric acid aqueous solution used in nitric acid electrolysis described later and a sulfuric acid aqueous solution waste solution used in an anodic oxidation treatment step described later can be suitably used.

  In the composition management of the desmut treatment liquid, a method of managing by conductivity and temperature, a method of managing by conductivity, specific gravity and temperature, and a conductivity and superconductivity corresponding to a matrix of acidic solution concentration and aluminum ion concentration. Either of the methods managed by the propagation speed of sound waves and temperature can be selected and used.

  In the first desmutting treatment, it is preferable to use an acidic solution containing 1 to 400 g / L acid and 0.1 to 5 g / L aluminum ions.

  The temperature of the acidic solution is preferably 20 ° C. or more, more preferably 30 ° C. or more, and preferably 70 ° C. or less, more preferably 60 ° C. or less.

  In the first desmutting treatment, the treatment time is preferably 1 second or longer, more preferably 4 seconds or longer, and preferably 60 seconds or shorter, more preferably 40 seconds or shorter. .

Examples of the method of bringing the aluminum plate into contact with the acidic solution include, for example, a method of passing the aluminum plate through a bath containing the acidic solution, a method of immersing the aluminum plate in a bath containing the acidic solution, and an acidic solution containing aluminum. The method of spraying on the surface of a board is mentioned.
Among these, a method in which an acidic solution is sprayed on the surface of an aluminum plate is preferable. Specifically, a method of spraying an etching solution in an amount of 10 to 100 L / min per spray tube from a spray tube having φ2 to 5 mm holes at a pitch of 10 to 50 mm is preferable. It is preferable to provide a plurality of spray tubes.

After the desmutting process is completed, it is preferable to drain the liquid with a nip roll, and further perform the water washing process for 1 to 10 seconds, and then drain the liquid with a nip roll.
The water washing treatment is the same as the water washing treatment after the alkali etching treatment. However, the amount of liquid per spray tip is preferably 1 to 20 L / min.

  In the first desmutting treatment, when the overflow waste solution of the nitric acid aqueous solution used in the subsequent nitric acid electrolysis is used as the desmutting treatment solution, the surface of the aluminum plate is not subjected to the draining with a nip roll and the water washing treatment after the desmutting treatment. It is preferable to handle the aluminum plate up to the nitric acid electrolysis step while spraying a desmut treatment solution as necessary so that it does not dry.

<First electrochemical surface roughening treatment>
The first electrochemical surface roughening treatment is an electrochemical surface roughening treatment in an aqueous solution containing nitric acid or hydrochloric acid. In the first aspect of the present invention, an electrochemical surface roughening treatment is performed in an aqueous solution containing nitric acid.
By performing the first electrochemical roughening treatment and the second electrochemical roughening treatment described later in this order, a grain shape with a highly uniform uneven structure is formed on the surface of the aluminum plate. As a result, stain resistance and printing durability can be improved. The average roughness R _a of the first electrochemical graining treatment after the aluminum plate surface is preferably 0.2 to 1.0 [mu] m.

<Nitric acid electrolysis>
When the electrochemical surface roughening treatment (nitric acid electrolysis) in an aqueous solution containing nitric acid is performed as the first electrochemical surface roughening treatment, a suitable uneven structure can be formed on the surface of the aluminum plate.

As the aqueous solution containing nitric acid, an aqueous solution used for electrochemical surface roughening using ordinary direct current or alternating current can be used. For example, nitric acid having nitrate ions such as aluminum nitrate, sodium nitrate, and ammonium nitrate in an aqueous solution of nitric acid having a concentration of 1 to 100 g / L (10 g / L or less in the lithographic printing plate support according to the first aspect of the present invention). At least one of the compounds can be added and used in a range from 1 g / L to saturation.
Moreover, the element contained in aluminum alloy plates, such as iron, copper, manganese, nickel, titanium, magnesium, and silicon, may melt | dissolve in the aqueous solution containing nitric acid. Hypochlorous acid or hydrogen peroxide may be contained in an amount of 1 to 100 g / L.
Specifically, aluminum nitrate is dissolved in an aqueous nitric acid solution having a nitric acid concentration of 5 to 15 g / L (10 g / L or less in the lithographic printing plate support according to the first aspect of the present invention) to obtain an aluminum ion concentration of 3 A liquid adjusted to be ˜7 g / L is preferable.

  In the lithographic printing plate support according to the first aspect of the present invention, the concentration of nitric acid in the aqueous solution containing nitric acid is 10 g / L or less. Thereby, even if it is a case where a batch type intermediate annealing apparatus is used, an electrochemical roughening process becomes uniform and surface quality nonuniformity becomes difficult to produce. Therefore, the lithographic printing plate support of the first aspect of the present invention can be produced at low cost in a short time, has a uniform surface appearance, and is subjected to a uniform electrolytic surface roughening treatment. . Specifically, without depending on an expensive continuous annealing apparatus or high-temperature batch annealing conditions, even if the crystal grains are somewhat large, the appearance failure is suppressed and a uniform electrolytic surface-roughening treatment is realized.

  The temperature of the aqueous solution containing nitric acid is preferably 20 ° C. or higher, and preferably 55 ° C. or lower.

  Pits having an average opening diameter of 1 to 10 μm can be formed by nitric acid electrolysis. However, when the amount of electricity is relatively large, the electrolytic reaction is concentrated, and honeycomb pits exceeding 10 μm are also generated.

To obtain such a grain, the total amount of electricity furnished to anode reaction on the aluminum plate up until the electrolysis reaction is completed is preferably at 150C / dm ² or more, at 170C / dm ² or more more preferably, but preferably not 600C / dm ² or less, more preferably 500C / dm ² or less. The current density at this time is preferably from 20 to 100 A / dm ² at the peak value of the current in the case of using the alternating current, preferably in the case of using a DC is 20 to 100 A / dm ^2.

<Hydrochloric acid electrolysis>
When performing the electrochemical surface roughening treatment (hydrochloric acid electrolysis) in an aqueous solution containing hydrochloric acid as the first electrochemical surface roughening treatment,

As the aqueous solution containing hydrochloric acid, those used for electrochemical surface roughening treatment using ordinary direct current or alternating current can be used. For example, nitric acid compounds capable of generating nitrate ions such as aluminum nitrate, sodium nitrate, ammonium nitrate in an aqueous hydrochloric acid solution having a concentration of 1-30 g / L, preferably 2-10 g / L, and / or aluminum chloride, sodium chloride, ammonium chloride, etc. At least one of the hydrochloric acid compounds capable of generating the chloride ion can be added and used in the range from 1 g / L to saturation.
Moreover, the aqueous solution containing hydrochloric acid can also contain the compound which forms a complex with copper in the ratio of 1-200 g / L.
Furthermore, the element contained in aluminum alloy plates, such as iron, copper, manganese, nickel, titanium, magnesium, and silicon, may melt | dissolve in the aqueous solution containing hydrochloric acid. Hypochlorous acid or hydrogen peroxide may be contained in an amount of 1 to 100 g / L.

Specifically, an aluminum salt (for example, aluminum chloride, AlCl ₃ .6H ₂ O) is dissolved in a hydrochloric acid aqueous solution having a hydrochloric acid concentration of ₂ to 10 g / L to make the aluminum ion concentration 3 to 7 g / L, preferably 4 to The liquid adjusted so that it may become 6 g / L is preferable.
When electrochemical surface roughening treatment is performed using such a hydrochloric acid aqueous solution, the surface shape by the surface roughening treatment becomes uniform, even if a low-purity aluminum alloy plate or a high-purity aluminum alloy plate is used, Processing unevenness due to the surface roughening treatment does not occur, and it is possible to achieve both excellent printing durability and stain resistance when using a lithographic printing plate.

  The temperature of the aqueous solution containing hydrochloric acid is preferably 20 ° C or higher, more preferably 30 ° C or higher, more preferably 55 ° C or lower, and even more preferably 50 ° C or lower.

As an additive, an apparatus, a power source, a current density, a flow rate, and a temperature in an aqueous solution containing hydrochloric acid, those known as those used for electrochemical surface roughening can be used.
As the power source, AC or DC is used, but AC is preferable.

Since hydrochloric acid itself has a strong ability to dissolve aluminum, fine irregularities can be formed on the surface by applying a slight current. The fine irregularities have an average opening diameter of 0.01 to 0.4 μm and are uniformly generated on the entire surface of the aluminum plate.
Further, when the amount of electricity is increased (total amount of electricity (anode reaction) is 150 to 2000 C / dm ² ), pits having an average opening diameter of 0.01 to 0.4 μm on the surface and having an average opening diameter of 1 to 30 μm Is generated. In order to obtain such a grain, the total amount of electricity involved in the anode reaction of the aluminum plate at the time when the electrolytic reaction is completed is preferably 10 C / dm ² or more, and more preferably 50 C / dm ² or more. Is more preferably 100 C / dm ² or more. But preferably not more 2000C / dm ² or less, more preferably 600C / dm ² or less.
The current density is preferably ²⁰ to 100 A / dm ² at the peak value of the current.

  When hydrochloric acid electrolysis is performed on the aluminum alloy plate under the above-mentioned conditions with a large amount of electricity, large undulations and fine irregularities can be formed simultaneously, and the large undulations can be made more uniform by the second alkali etching process described later. Thus, the stain resistance can be improved.

  The first electrochemical surface roughening treatment using an aqueous solution containing nitric acid or hydrochloric acid is performed by, for example, the electrochemical grain method described in Japanese Patent Publication No. 48-28123 and British Patent No. 896,563 ( Electrolytic grain method). This electrolytic grain method uses a sinusoidal alternating current, but it may be performed using a special waveform as described in JP-A-52-58602. Further, the waveform described in JP-A-3-79799 can also be used. JP-A-55-158298, JP-A-56-28898, JP-A-52-58602, JP-A-52-152302, JP-A-54-85802, JP-A-60-190392, JP-A-58-120531, JP-A-63-176187, JP-A-1-5889, JP-A-1-280590, JP-A-1-118489, JP-A-1-148592, and JP-A-1-17896. JP-A-1-188315, JP-A-1-1549797, JP-A-2-235794, JP-A-3-260100, JP-A-3-253600, JP-A-4-72079, JP-A-4-72098, The methods described in JP-A-3-267400 and JP-A-1-141094 can also be applied. In addition to the above, it is also possible to perform electrolysis using an alternating current having a special frequency that has been proposed as a method of manufacturing an electrolytic capacitor. For example, it is described in US Pat. Nos. 4,276,129 and 4,676,879.

Various electrolyzers and power sources have been proposed, including US Pat. No. 4,203,637, JP-A-56-123400, JP-A-57-59770, JP-A-53-12738, JP 53-32821, JP 53-32222, JP 53-32823, JP 55-122896, JP 55-13284, JP 62-127500, JP Those described in JP-A-1-52100, JP-A-1-52098, JP-A-60-67700, JP-A-1-230800, JP-A-3-257199 and the like can be used.
Further, JP-A-52-58602, JP-A-52-152302, JP-A-53-12738, JP-A-53-12739, JP-A-53-32821, JP-A-53-32822, JP 53-32833, JP 53-32824, JP 53-32825, JP 54-85802, JP 55-122896, JP 55-13284, JP 48-28123, JP-B-51-7081, JP-A-52-13338, JP-A-52-133840, JP-A-52-133844, JP-A-52-133845, JP-A-53-149135 And those described in JP-A No. 54-146234 and the like.

As the conductivity meter and the specific gravity meter, it is preferable to use those that are temperature-compensated. As the specific gravity meter, a differential pressure type is preferably used.
Samples taken from the electrolyte for use in measuring the liquid composition are used for measurement after being controlled at a constant temperature (eg, 40 ± 0.5 ° C.) using a heat exchanger different from the electrolyte. However, it is preferable in that the accuracy of measurement is increased.

  The AC power supply wave used for the electrochemical surface roughening treatment is not particularly limited, and a sine wave (sine wave), a rectangular wave, a trapezoidal wave, a triangular wave, or the like is used.

An AC duty ratio of 1: 2 to 2: 1 can be used. However, as described in Japanese Patent Laid-Open No. 5-195300, the duty ratio is used in an indirect power feeding method in which no conductor roll is used for aluminum. Is preferably 1: 1.
An AC frequency of 0.1 to 120 Hz can be used, but 50 to 70 Hz is preferable in terms of equipment. If it is lower than 50 Hz, the carbon electrode of the main electrode is likely to be dissolved, and if it is higher than 70 Hz, it is likely to be affected by the inductance component on the power supply circuit and the power supply cost is increased.

  As the electrolytic cell, electrolytic cells used for known surface treatments such as a vertical type, a flat type, and a radial type can be used, but a radial type electrolytic cell as described in JP-A-5-195300 is particularly preferable. . The electrolytic solution passing through the electrolytic cell may be parallel to the traveling direction of the aluminum web or may be a counter.

  In addition, in the electrochemical surface roughening treatment using direct current, an electrolytic solution used for the normal electrochemical surface roughening treatment using direct current can be used. Specifically, the same electrolyte solution used for the electrochemical surface roughening treatment using the alternating current can be used.

The DC power supply wave used for the electrochemical surface roughening treatment is not particularly limited as long as the current does not change in polarity. Smoothed continuous direct current is preferred.
The electrochemical surface roughening treatment using direct current can be performed by any of a batch method, a semi-continuous method and a continuous method, but is preferably performed by a continuous method.

  The apparatus used for the electrochemical surface roughening treatment using direct current applies a direct current voltage between alternately arranged anodes and cathodes, and passes through the aluminum plate at a distance from the anodes and the cathodes. If it can be made, it will not be specifically limited.

An electrode is not specifically limited, The conventionally well-known electrode used for an electrochemical roughening process can be used.
As the anode, for example, a valve metal such as titanium, tantalum, or niobium is plated or clad with a platinum group metal; the valve metal is coated with a platinum group metal oxide or sintered. Aluminium; stainless steel. Among these, a valve metal obtained by cladding platinum is preferable. The life of the anode can be further extended by a method such as water-cooling by passing water through the electrode.
As the cathode, for example, a metal that does not dissolve when the electrode potential is negative can be selected and used from the Boolean Bay diagram. Among these, carbon is preferable.

  The arrangement of the electrodes can be appropriately selected according to the wave structure. In addition, by changing the length of the aluminum plate between the anode and the cathode in the traveling direction, changing the passage speed of the aluminum plate, changing the flow rate of the electrolyte, the liquid temperature, the liquid composition, the current density, etc. Can be adjusted. In addition, in the case of using an apparatus in which the anode tank and the cathode tank are separated from each other, the electrolysis conditions of each treatment tank can be changed.

After the first electrochemical surface roughening treatment is completed, it is preferable to drain the liquid with a nip roll, and further perform the water washing treatment for 1 to 10 seconds and then drain the liquid with a nip roll.
The washing treatment is preferably carried out using a spray tube. As the spray tube used for the water washing treatment, for example, a spray tube having a plurality of spray tips in the width direction of the aluminum plate in which fan water spreads in a fan shape can be used. The distance between spray tips is preferably 20 to 100 mm, and the amount of liquid per spray tip is preferably 1 to 20 L / min. It is preferable to use a plurality of spray tubes.

<Second alkali etching treatment>
The second alkali etching process performed between the first electrochemical surface roughening process and the second electrochemical surface roughening process is to dissolve the smut generated by the first electrochemical surface roughening process; And it is performed for the purpose of dissolving the edge part of the pit formed by the 1st electrochemical roughening process. As a result, the edge portion of the large pit formed by the first electrochemical surface roughening process is melted and the surface becomes smooth, and the ink is less likely to be caught on the edge portion. Therefore, the lithographic printing plate precursor having excellent stain resistance Can be obtained.
Since the second alkali etching process is basically the same as the first alkali etching process, only different points will be described below.

In the second alkali etching treatment, the concentration of the alkali solution is preferably 30 g / L or more, more preferably 300 g / L or more, and preferably 500 g / L or less, 450 g / L. The following is more preferable.
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 1 g / L or more, more preferably 50 g / L or more, and preferably 200 g / L or less, more preferably 150 g / L or less. Such an alkaline solution can be prepared using, for example, water, a 48 mass% sodium hydroxide aqueous solution, and sodium aluminate.

In the second alkali etching treatment, the etching amount is preferably at 0.05 g / m ² or more, more preferably 0.1 g / m ² or more, and it is at 4g / m ² or less Preferably, it is 3.5 g / m ² or less. When the etching amount is 0.05 g / m ² or more, in the non-image portion of the lithographic printing plate, the edge portion of the pit generated by the first electrochemical roughening treatment becomes smooth, and the ink is difficult to get caught. Excellent stain resistance. On the other hand, when the etching amount is 4 g / m ² or less, the unevenness generated by the first electrochemical surface roughening treatment becomes large, so that the printing durability is excellent.

<Second desmut treatment>
After the second alkali etching treatment, it is preferable to perform pickling (second desmut treatment) in order to remove dirt (smut) remaining on the surface. The second desmut process can be performed in the same manner as the first desmut process.

In the second desmut treatment, nitric acid or sulfuric acid is preferably used.
In the second desmutting treatment, it is preferable to use an acidic solution containing 1 to 400 g / L acid and 0.1 to 8 g / L aluminum ions.
When using sulfuric acid, specifically, use a solution prepared by dissolving aluminum sulfate in a sulfuric acid aqueous solution having a sulfuric acid concentration of 100 to 350 g / L so that the aluminum ion concentration becomes 0.1 to 5 g / L. Can do. Moreover, the overflow waste liquid of the electrolyte solution used for the anodizing process mentioned later can also be used.

In the second desmut treatment, the treatment time is preferably 1 second or more, more preferably 4 seconds or more, and preferably 60 seconds or less, more preferably 20 seconds or less. .
In the second desmutting treatment, the temperature of the aqueous acid solution is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, and preferably 70 ° C. or lower, preferably 60 ° C. or lower. More preferred.

<Second electrochemical roughening treatment>
The second electrochemical roughening treatment is an electrochemical roughening treatment using alternating current or direct current in an aqueous solution containing hydrochloric acid. In the present invention, only the first electrochemical surface roughening treatment described above may be performed, but by combining this second electrochemical surface roughening treatment, a more complicated uneven structure is formed on the surface of the aluminum plate. Thus, the printing durability can be improved.

The second electrochemical roughening treatment is basically the same as the hydrochloric acid electrolysis performed as the first electrochemical roughening treatment described above.
In the second electrochemical roughening treatment, the total amount of electricity that the aluminum plate takes part in the anodic reaction is preferably 10 to 200 C / dm ² when the electrochemical roughening treatment is completed. Among these, in order not to greatly break the rough surface formed by the first electrochemical surface roughening treatment, 10 to 100 C / dm ² is preferable, and 50 to 80 C / dm ² is more preferable.

<Third alkali etching treatment>
The third alkali etching treatment performed after the second electrochemical roughening treatment is performed by dissolving the smut generated by the second electrochemical roughening treatment, and by the second electrochemical roughening treatment. This is performed for the purpose of dissolving the edge portion of the formed pit. Since the third alkali etching process is basically the same as the first alkali etching process, only different points will be described below.

In the third alkali etching treatment, the etching amount is preferably at 0.05 g / m ² or more, more preferably 0.1 g / m ² or more, is 0.3 g / m ² or less Of 0.25 g / m ² or less is more preferable. When the etching amount is 0.05 g / m ² or more, in the non-image portion of the lithographic printing plate, the edge portion of the pit generated by the second electrochemical surface roughening process becomes smooth, and the ink is not easily caught. Excellent stain resistance. On the other hand, when the etching amount is 0.3 g / m ² or less, the unevenness generated in the first electrochemical surface roughening treatment and the second electrochemical surface roughening treatment becomes large, and thus the printing durability is excellent. Become a thing.

In the third alkali etching treatment, the concentration of the alkali solution is preferably 30 g / L or more, and in order not to make the unevenness caused by the second electrochemical roughening treatment too small, 100 g / L or less is preferable, and 70 g / L or less is more preferable.
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 1 g / L or more, more preferably 3 g / L or more, and preferably 50 g / L or less, more preferably 8 g / L or less. Such an alkaline solution can be prepared using, for example, water, a 48 mass% sodium hydroxide aqueous solution, and sodium aluminate.

In the third alkali etching treatment, the temperature of the alkaline solution is preferably 25 ° C or higher, more preferably 30 ° C or higher, and preferably 60 ° C or lower, and 50 ° C or lower. Is more preferable.
In the third alkali etching treatment, the treatment time is preferably 1 second or longer, more preferably 2 seconds or longer, more preferably 30 seconds or shorter, and more preferably 10 seconds or shorter. preferable.

When the first alkali etching treatment, nitric acid electrolysis, second alkali etching treatment, second electrochemical surface roughening treatment and third alkali etching treatment are performed in combination, the total amount of electricity in the anode reaction in nitric acid electrolysis is 65 to 500 C. / Dm ² , 0.1 g / m ² or more of aluminum is chemically dissolved, and in the second electrochemical roughening treatment, the total amount of electricity in the anode reaction is 25 to 100 C / dm ^2, and the third alkali etching In the treatment, 0.03 g / m ² or more of aluminum is preferably chemically dissolved. If the aluminum alloy base plate of the present invention is roughened with this combination, a lithographic printing plate support excellent in stain resistance and printing durability can be obtained.

<Third desmut processing>
After the third alkali etching treatment, pickling (third desmutting treatment) is preferably performed to remove dirt (smut) remaining on the surface. Since the third desmut process is basically the same as the first desmut process, only the differences will be described below.
In the third desmutting treatment, it is preferable to use an acidic solution containing 5-400 g / L acid and 0.5-8 g / L aluminum ions. In the case of using sulfuric acid, specifically, a solution prepared by dissolving aluminum sulfate in a sulfuric acid aqueous solution having a sulfuric acid concentration of 100 to 350 g / L to adjust the aluminum ion concentration to 1 to 5 g / L is preferable.

In the third desmut treatment, the treatment time is preferably 1 second or longer, more preferably 4 seconds or longer, and preferably 60 seconds or shorter, more preferably 15 seconds or shorter. .
In the third desmut process, when the same type of electrolyte as that used in the subsequent anodic oxidation process is used as the desmut process liquid, the draining with a nip roll and the water washing process can be omitted after the desmut process.

<Anodizing treatment>
The aluminum plate treated as described above can be further anodized. The anodizing treatment can be performed by a method conventionally used in this field. In this case, for example, in a solution having a sulfuric acid concentration of 50 to 300 g / L and an aluminum concentration of 5% by mass or less, an anodized film can be formed by energizing an aluminum plate as an anode. As a solution used for the anodizing treatment, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid and the like can be used alone or in combination of two or more.

Under the present circumstances, the component normally contained at least in an aluminum plate, an electrode, tap water, groundwater, etc. may be contained in electrolyte solution. Furthermore, the 2nd, 3rd component may be added. Examples of the second and third components here include Na, K, Mg, Li, Ca, and Ti.
Metal ions such as Al, V, Cr, Mn, Fe, Co, Ni, Cu and Zn; cations such as ammonium ions; nitrate ions, carbonate ions, chloride ions, phosphate ions, fluoride ions, sulfurous acid Examples include anions such as ions, titanate ions, silicate ions, and borate ions, which may be contained at a concentration of about 0 to 10,000 ppm.

The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined unconditionally. In general, however, the electrolyte concentration is 1 to 80% by mass, the solution temperature is 5 to 70 ° C., and the current density is 0.5. ˜60 A / dm ² , voltage 1 to 100 V, and electrolysis time 15 seconds to 50 minutes are appropriate and adjusted so as to obtain a desired anodic oxide film amount.

  Further, JP-A-54-81133, JP-A-57-47894, JP-A-57-51289, JP-A-57-51290, JP-A-57-54300, JP-A-57-136596, JP-A-58-107498, JP-A-60-200366, JP-A-62-136696, JP-A-63-176494, JP-A-4-17697, JP-A-4-280997, JP-A-6-280997 The methods described in JP-A-207299, JP-A-5-24377, JP-A-5-32083, JP-A-5-125597, JP-A-5-195291 and the like can also be used.

  Of these, as described in JP-A-54-12853 and JP-A-48-45303, it is preferable to use a sulfuric acid solution as the electrolytic solution. The sulfuric acid concentration in the electrolytic solution is preferably 10 to 300 g / L (1 to 30% by mass), more preferably 50 to 200 g / L (5 to 20% by mass), and the aluminum ion concentration. Is preferably 1 to 25 g / L (0.1 to 2.5% by mass), more preferably 2 to 10 g / L (0.2 to 1% by mass). Such an electrolytic solution can be prepared, for example, by adding aluminum sulfate or the like to dilute sulfuric acid having a sulfuric acid concentration of 50 to 200 g / L.

  The composition management of the electrolyte is conducted using the same method as in the case of nitric acid electrolysis described above, and the conductivity, specific gravity and temperature, or conductivity and ultrasonic wave propagation corresponding to the matrix of sulfuric acid concentration and aluminum ion concentration. It is preferable to control by speed and temperature.

  The liquid temperature of the electrolytic solution is preferably 25 to 55 ° C, more preferably 30 to 50.

When anodizing is performed in an electrolytic solution containing sulfuric acid, direct current may be applied between the aluminum plate and the counter electrode, or alternating current may be applied.
When a direct current is applied to the aluminum plate, the current density is preferably from 1 to 60 A / dm ^2, and more preferably 5 to 40 A / dm ^2.
In the case of continuous anodizing treatment, at the beginning of anodizing treatment, so that current is concentrated on a part of the aluminum plate and so-called “burning” (part where the film becomes thicker than the surroundings) does not occur. It is preferable to increase the current density to 30 to 50 A / dm ² or higher as the anodic oxidation process proceeds with a current flowing at a low current density of 5 to 10 A / m ² .
By performing anodizing treatment under such conditions, a porous film having many pores called micropores can be obtained. Usually, the average pore diameter is about 5 to 50 nm, and the average pore density is 300. ˜800 / μm ² or so.

The amount of the anodized film is preferably 1 to 5 g / m ² . If it is less than 1 g / m ² , the plate is likely to be scratched. On the other hand, if it exceeds 5 g / m ² , a large amount of power is required for production, which is economically disadvantageous. The amount of the anodized film is more preferably 1.5 to 4 g / m ² . Moreover, it is preferable to carry out so that the difference in the amount of the anodized film between the center portion of the aluminum plate and the vicinity of the edge portion is 1 g / m ² or less.

  As electrolysis apparatuses used for anodizing treatment, those described in JP-A-48-26638, JP-A-47-18739, JP-B-58-24517, JP-A-2001-11698, etc. Can be used.

<Sealing treatment>
In this invention, you may perform the sealing process which seals the micropore which exists in an anodic oxide film as needed. The sealing treatment can be performed according to a known method such as boiling water treatment, hot water treatment, steam treatment, sodium silicate treatment, nitrite treatment, ammonium acetate treatment and the like. For example, even if the sealing treatment is carried out by the apparatus and method described in JP-B-56-12518, JP-A-4-4194, JP-A-5-20296, JP-A-5-179482, etc. Good.

<Hydrophilic treatment>
A hydrophilization treatment may be performed after the anodizing treatment or the sealing treatment. Examples of the hydrophilization treatment include treatment with potassium fluorozirconate described in US Pat. No. 2,946,638 and phosphomolybdate described in US Pat. No. 3,201,247. Treatment, alkyl titanate treatment described in British Patent 1,108,559, polyacrylic acid treatment described in German Patent 1,091,433, German Patent 1,134, No. 093 and British Patent No. 1,230,447, polyvinylphosphonic acid treatment, Japanese Patent Publication No. 44-6409, phosphonic acid treatment, US Pat. No. 3,307,951 Phytic acid treatment described in the specification of JP, No. 58-16893 and JP-A No. 58-18291 Treatment with a salt of a molecular compound and a divalent metal, as described in US Pat. No. 3,860,426, hydrophilic cellulose (eg, zinc acetate) containing a water-soluble metal salt (eg, zinc acetate) Carboxymethyl cellulose) is provided with a primer layer, and a water-soluble polymer having a sulfo group described in JP-A-59-101651.

Further, phosphates described in JP-A No. 62-019494, water-soluble epoxy compounds described in JP-A No. 62-033692, and JP-A No. 62-097892 Phosphoric acid modified starch, diamine compounds described in JP-A-63-056498, inorganic or organic acids of amino acids described in JP-A-63-130391, JP-A-63-145092 Organic phosphonic acids containing carboxy group or hydroxy group, compounds having amino group and phosphonic acid group described in JP-A-63-165183, and JP-A-2-316290 Specific carboxylic acid derivatives, phosphate esters described in JP-A-3-215095, JP-A-3-261592 Compounds having one amino group and one oxygen acid group of phosphorus described in the report, aliphatic or aromatic phosphonic acids such as phenylphosphonic acid described in JP-A-5-246171, Treatment by undercoating using a compound containing an S atom such as thiosalicylic acid described in JP-A-1-307745, a compound having a group of phosphorus oxyacids described in JP-A-4-282737, etc. Can be mentioned.
Further, coloring with an acid dye described in JP-A-60-64352 can also be performed.

  Hydrophilicity can also be achieved by soaking in an aqueous solution of an alkali metal silicate such as sodium silicate or potassium silicate, or by applying a hydrophilic vinyl polymer or hydrophilic compound to form a hydrophilic primer layer. It is preferable to carry out the treatment.

Hydrophilization treatment with an aqueous solution of an alkali metal silicate such as sodium silicate and potassium silicate is described in US Pat. No. 2,714,066 and US Pat. No. 3,181,461. It can be performed according to methods and procedures.
Examples of the alkali metal silicate include sodium silicate, potassium silicate, and lithium silicate. The aqueous solution of alkali metal silicate may contain an appropriate amount of sodium hydroxide, potassium hydroxide, lithium hydroxide or the like.
The aqueous solution of alkali metal silicate may contain an alkaline earth metal salt or a Group 4 (Group IVA) metal salt. Examples of the alkaline earth metal salt include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate; sulfates; hydrochlorides; phosphates; acetates; oxalates; Examples of Group 4 (Group IVA) metal salts include titanium tetrachloride, titanium trichloride, potassium fluoride titanium, potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium tetrachloride. Is mentioned. These alkaline earth metal salts and Group 4 (Group IVA) metal salts are used alone or in combination of two or more.

The amount of Si adsorbed by the alkali metal silicate treatment can be measured with a fluorescent X-ray analyzer, and the amount of adsorption is preferably about 1.0 to 15.0 mg / m ² .
By this alkali metal silicate treatment, the effect of improving the dissolution resistance to the alkaline developer on the surface of the lithographic printing plate support is obtained, and the dissolution of the aluminum component into the developer is suppressed, and the developer fatigue It is possible to reduce the occurrence of development residue due to the above.

<Drying>
After obtaining the lithographic printing plate support as described above, it is preferable to dry the surface of the lithographic printing plate support before providing the image recording layer. Drying is preferably performed after the final treatment of the surface treatment, after washing with water and draining with a nip roll.
The drying temperature is preferably 70 ° C or higher, more preferably 80 ° C or higher, preferably 110 ° C or lower, more preferably 100 ° C or lower.
The drying time is preferably 1 second or more, more preferably 2 seconds or more, and preferably 20 seconds or less, more preferably 15 seconds.

<Management of liquid composition>
In the present invention, it is preferable to manage the composition of various processing solutions used for the surface treatment described above by the method described in JP-A-2001-121837. Prepare a large number of treatment liquid samples with various concentrations in advance, measure the propagation speed of ultrasonic waves at two liquid temperatures, create a matrix data table, It is preferable to measure the propagation speed of the light in real time and control the concentration based on the measurement. In particular, in the desmutting treatment, when an electrolytic solution having a sulfuric acid concentration of 250 g / L or more is used, it is preferable to control the concentration by the method described above.
In addition, it is preferable that each electrolyte solution used for an electrolytic roughening process and an anodic oxidation process is 100 ppm or less of Cu concentration. If the Cu concentration is too high, Cu is deposited on the aluminum plate when the line is stopped, and Cu deposited when the line is operated again may be transferred to a pass roll, which may cause processing unevenness.

<Surface shape of the back surface of the support>
In the second lithographic printing plate support of the embodiment of the present invention, the average surface roughness R _a in the rolling direction is 0.15 to 0.35, the average surface roughness R _a in the width direction is 0.20 ~ 0.40. As a result, the transportability and interleaf separation of the planographic printing plate precursor and the planographic printing plate are excellent. As a result, a decrease in printing productivity can be prevented.

[Lithographic printing plate precursor]
The lithographic printing plate support of the present invention can be provided with an image recording layer to form a lithographic printing plate precursor. A photosensitive composition is used for the image recording layer.
Examples of the photosensitive composition suitably used in the present invention include a thermal positive photosensitive composition containing an alkali-soluble polymer compound and a photothermal conversion substance (hereinafter, this composition and an image recording layer using the same). ), A thermal negative photosensitive composition containing a curable compound and a photothermal conversion substance (hereinafter also referred to as “thermal negative type”), a photopolymerizable photosensitive composition (hereinafter referred to as “thermal positive type”). , Also referred to as “photopolymer type”), negative photosensitive composition containing diazo resin or photocrosslinking resin (hereinafter also referred to as “conventional negative type”), and positive photosensitive composition containing quinonediazide compound. Product (hereinafter also referred to as “conventional positive type”), a photosensitive composition that does not require a special development step (hereinafter referred to as “the conventional positive type”). As the referred to as "non-treatment type".), And the like.
Of these, a thermal positive type, a thermal negative type, a photopolymer type, and an unprocessed type which are laser direct-drawing type image recording layers are preferable, and a thermal positive type and a photopolymer type are more preferable. Hereinafter, these suitable photosensitive compositions will be described.

<Thermal positive type>
<Photosensitive layer>
The thermal positive type photosensitive composition contains an alkali-soluble polymer compound and a photothermal conversion substance. In the thermal positive type image recording layer, the photothermal conversion substance converts the energy of light such as infrared lasers into heat, which effectively eliminates the interaction that reduces the alkali solubility of alkali-soluble polymer compounds. To do.

Examples of the alkali-soluble polymer compound include a resin containing an acidic group in the molecule and a mixture of two or more thereof. In particular, a phenolic hydroxy group, sulfonamide group (in -SO ₂ NH-R (wherein, R represents a hydrocarbon group.)), Active imino group _{(-SO 2 NHCOR, -SO 2 NHSO} 2 R, -CONHSO A resin having an acidic group such as ₂ R (wherein R has the same meaning as described above) is preferable in terms of solubility in an alkali developer.
In particular, a resin having a phenolic hydroxy group is preferable in that it has excellent image-forming properties when exposed to light such as an infrared laser, and examples thereof include phenol-formaldehyde resins, m-cresol-formaldehyde resins, p-cresol-formaldehyde resins, m- / p-mixed cresol-formaldehyde resin, phenol / cresol (any of m-, p- and m- / p-mixed) mixed-formaldehyde resin (phenol-cresol-formaldehyde co-condensation resin) and other novolak resins Are preferable.
Furthermore, the polymer compound described in JP-A No. 2001-305722 (particularly [0023] to [0042]), and the repetition represented by the general formula (1) described in JP-A No. 2001-215893 Preferred examples also include polymer compounds containing units, and polymer compounds described in JP-A No. 2002-311570 (particularly [0107]).

  Preferable examples of the photothermal conversion substance include pigments or dyes having a light absorption region in the infrared region having a wavelength of 700 to 1200 nm in terms of recording sensitivity. Examples of the dye include azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes (for example, , Nickel thiolate complex). Among these, cyanine dyes are preferable, and cyanine dyes represented by the general formula (I) described in JP 2001-305722 A are particularly preferable.

The thermal positive type photosensitive composition may contain a dissolution inhibitor. As the dissolution inhibitor, for example, dissolution inhibitors described in JP-A-2001-305722, [0053] to [0055] are preferably exemplified.
In addition, in the thermal positive type photosensitive composition, as a additive, a sensitivity modifier, a printing agent for obtaining a visible image immediately after heating by exposure, a compound such as a dye as an image colorant, a coating property In addition, it is preferable to include a surfactant for improving the processing stability. For these, compounds described in JP-A-2001-305722, [0056] to [0060] are preferable.
The photosensitive composition described in detail in Japanese Patent Application Laid-Open No. 2001-305722 is also preferably used in other respects.

Further, the thermal positive type image recording layer is not limited to a single layer but may have a two-layer structure.
As an image recording layer having a two-layer structure (multilayer image recording layer), a lower layer (hereinafter referred to as “A layer”) having excellent printing durability and solvent resistance is provided on the side close to the support, and a positive layer is provided thereon. A type provided with a layer having excellent image formability (hereinafter referred to as “B layer”) is preferable. This type has high sensitivity and can realize a wide development latitude. The B layer generally contains a photothermal conversion substance. Preferred examples of the photothermal conversion substance include the dyes described above.
As the resin used in the A layer, a polymer having a monomer having a sulfonamide group, an active imino group, a phenolic hydroxy group or the like as a copolymerization component is preferably used because it has excellent printing durability and solvent resistance. . As the resin used for the B layer, an alkaline aqueous solution-soluble resin having a phenolic hydroxy group is preferably exemplified.
In addition to the resin, the composition used for the A layer and the B layer can contain various additives as necessary. Specifically, various additives as described in [0062] to [0085] of JP-A-2002-3233769 are preferably used. Further, the additives described in [0053] to [0060] of JP-A-2001-305722 described above are also preferably used.
About each component which comprises A layer and B layer, and its content, it is preferable to make it describe in Unexamined-Japanese-Patent No. 11-218914.

<Intermediate layer>
An intermediate layer is preferably provided between the thermal positive type image recording layer and the support. As the component contained in the intermediate layer, various organic compounds described in [0068] of JP-A No. 2001-305722 are preferably exemplified.
Further, an intermediate layer containing a polymer having a monomer having an acid group and a monomer having an onium group described in JP-A-2001-108538 is also preferably used. This intermediate layer is also suitably used for image recording layers other than the thermal positive type.

<Others>
As a method for producing a thermal positive type image recording layer and a plate making method, methods described in detail in JP-A No. 2001-305722 can be used.

<Thermal negative type>
The thermal negative photosensitive composition contains a curable compound and a photothermal conversion substance. The thermal negative type image recording layer is a negative photosensitive layer in which a portion irradiated with light such as an infrared laser is cured to form an image portion.
<Polymerized layer>
As one of the thermal negative type image recording layers, a polymerization type image recording layer (polymerization layer) is preferably exemplified. The polymerization layer contains a photothermal conversion substance, a radical generator, a radical polymerizable compound that is a curable compound, and a binder polymer. In the polymerization layer, infrared light absorbed by the light-to-heat conversion substance is converted into heat, the radical generator is decomposed by this heat to generate radicals, and the radical polymerizable compound is polymerized in a chain by the generated radicals and cured. .

As a photothermal conversion substance, the photothermal conversion substance used for the thermal positive type mentioned above is mentioned, for example. Specific examples of particularly preferred cyanine dyes include those described in JP-A-2001-133969, [0017] to [0019].
Preferred examples of the radical generator include onium salts. In particular, onium salts described in JP-A-2001-133969, [0030] to [0033] are preferable.
Examples of the radical polymerizable compound include compounds having at least one terminal ethylenically unsaturated bond, preferably two or more.
As the binder polymer, a linear organic polymer is preferably exemplified. Preferred examples include linear organic polymers that are soluble or swellable in water or weak alkaline water. Among them, a (meth) acrylic resin having an unsaturated group such as an allyl group or an acryloyl group or a benzyl group and a carboxy group in the side chain is preferable in that it has an excellent balance of film strength, sensitivity, and developability. .
As the radical polymerizable compound and the binder polymer, those described in detail in [0036] to [0060] of JP-A No. 2001-133969 can be used.

  The additive described in [0061] to [0068] of JP-A No. 2001-133969 is contained in the thermal negative photosensitive composition (for example, a surfactant for improving coatability). Is preferred.

  As a method for producing the polymerization layer and a plate making method, methods described in detail in JP-A No. 2001-133969 can be used.

<Acid cross-linked layer>
Further, as one of the thermal negative type image recording layers, an acid cross-linked image recording layer (acid cross-linked layer) is also preferably exemplified. The acid cross-linking layer comprises a photothermal conversion substance, a thermal acid generator, a compound that cross-links with an acid that is a curable compound (cross-linking agent), and an alkali-soluble polymer compound that can react with the cross-linking agent in the presence of an acid. contains. In the acid cross-linking layer, infrared light absorbed by the photothermal conversion substance is converted into heat, the heat acid generator is decomposed by this heat to generate an acid, and the generated acid reacts with the cross-linking agent and the alkali-soluble polymer compound. And harden.

Examples of the photothermal conversion substance include the same substances as those used for the polymerization layer.
Examples of the thermal acid generator include thermal decomposition compounds such as photoinitiators for photopolymerization, photochromic agents for dyes, and acid generators used in microresists.
Examples of the crosslinking agent include an aromatic compound substituted with a hydroxymethyl group or an alkoxymethyl group; a compound having an N-hydroxymethyl group, an N-alkoxymethyl group or an N-acyloxymethyl group; and an epoxy compound.
Examples of the alkali-soluble polymer compound include a novolak resin and a polymer having a hydroxyaryl group in the side chain.

<Photopolymer type>
The photopolymerization type photosensitive composition contains an addition polymerizable compound, a photopolymerization initiator, and a polymer binder.
As the addition polymerizable compound, an ethylenically unsaturated bond-containing compound capable of addition polymerization is preferably exemplified. The ethylenically unsaturated bond-containing compound is a compound having a terminal ethylenically unsaturated bond. Specifically, for example, it has a chemical form such as a monomer, a prepolymer, and a mixture thereof. Examples of monomers include esters of unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, maleic acid) and aliphatic polyhydric alcohol compounds, amides of unsaturated carboxylic acids and aliphatic polyvalent amine compounds. Is mentioned.
Moreover, as an addition polymerizable compound, a urethane type addition polymerizable compound is also preferably exemplified.

As the photopolymerization initiator, various photopolymerization initiators or a combination system (photoinitiation system) of two or more kinds of photopolymerization initiators can be appropriately selected depending on the wavelength of the light source to be used. For example, an initiation system described in JP-A-2001-22079, [0021] to [0023] is preferably exemplified.
The polymer binder not only functions as a film-forming agent for the photopolymerization type photosensitive composition, but is soluble or swellable in alkaline water because it is necessary to dissolve the image recording layer in an alkaline developer. An organic high molecular polymer is used. As such an organic polymer, those described in JP-A-2001-22079, [0036] to [0063] are preferably exemplified.

  In the photopolymer type photopolymerization type photosensitive composition, additives described in JP-A-2001-22079, [0079] to [0088] (for example, a surfactant for improving coatability) , Colorants, plasticizers, thermal polymerization inhibitors).

Further, it is preferable to provide an oxygen-blocking protective layer on the photopolymer type image recording layer in order to prevent the action of inhibiting the polymerization of oxygen. Examples of the polymer contained in the oxygen barrier protective layer include polyvinyl alcohol and copolymers thereof.
Furthermore, it is also preferable to provide an intermediate layer or an adhesive layer as described in [0124] to [0165] of JP-A-2001-228608.

<Conventional negative type>
The conventional negative-type photosensitive composition contains a diazo resin or a photocrosslinking resin. Among these, a photosensitive composition containing a diazo resin and an alkali-soluble or swellable polymer compound (binder) is preferable.
Examples of the diazo resin include a condensate of an aromatic diazonium salt and an active carbonyl group-containing compound such as formaldehyde; a condensate of p-diazophenylamines and formaldehyde and a hexafluorophosphate or a tetrafluoroborate. Organic solvent-soluble diazo resin inorganic salts which are reaction products of In particular, a high molecular weight diazo compound containing 20 mol% or more of a hexamer described in JP-A-59-78340 is preferable.
Examples of the binder include a copolymer containing acrylic acid, methacrylic acid, crotonic acid, or maleic acid as an essential component. Specifically, a multi-component copolymer of monomers such as 2-hydroxyethyl (meth) acrylate, (meth) acrylonitrile, (meth) acrylic acid as described in JP-A-50-118802, Examples thereof include multi-component copolymers composed of alkyl acrylate, (meth) acrylonitrile and unsaturated carboxylic acid as described in JP-A-56-4144.

  The conventional negative type photosensitive composition has, as an additive, a printing agent, dye, and flexibility and abrasion resistance described in JP-A-7-281425, [0014] to [0015]. It is preferable to contain a plasticizer for imparting, a compound such as a development accelerator, and a surfactant for improving coating properties.

  Under the conventional negative type photosensitive layer, an intermediate layer containing a polymer compound having a component having an acid group and a component having an onium group as described in JP-A-2000-105462 is provided. Is preferred.

<Conventional positive type>
The conventional positive-type photosensitive composition contains a quinonediazide compound. Among these, a photosensitive composition containing an o-quinonediazide compound and an alkali-soluble polymer compound is preferable.
Examples of the o-quinonediazide compound include esters of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride and phenol-formaldehyde resin or cresol-formaldehyde resin, described in US Pat. No. 3,635,709. And esters of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride and pyrogallol-acetone resin.
Examples of the alkali-soluble polymer compound include phenol-formaldehyde resin, cresol-formaldehyde resin, phenol-cresol-formaldehyde co-condensation resin, polyhydroxystyrene, N- (4-hydroxyphenyl) methacrylamide copolymer, A carboxy group-containing polymer described in JP-A-7-36184, an acrylic resin containing a phenolic hydroxy group as described in JP-A-51-34711, and described in JP-A-2-866 Examples thereof include acrylic resins having a sulfonamide group and urethane resins.

  Conventional positive type photosensitive compositions include compounds such as sensitivity modifiers, printing agents, dyes and the like described in JP-A-7-92660, [0024] to [0027] as additives. It is preferable to contain a surfactant for improving the coating property as described in [0031] of Kaihei 7-92660.

  Under the conventional positive type photosensitive layer, it is preferable to provide an intermediate layer similar to the intermediate layer suitably used for the above-described conventional negative type.

<Non-treatment type>
Examples of the non-processing type photosensitive composition include a thermoplastic fine particle polymer type, a microcapsule type, and a sulfonic acid-generating polymer-containing type. These are all heat-sensitive types containing a photothermal conversion substance. The photothermal conversion substance is preferably the same dye as that used in the above-described thermal positive type.

The thermoplastic fine particle polymer type photosensitive composition is obtained by dispersing a hydrophobic and heat-meltable fine particle polymer in a hydrophilic polymer matrix. In the image recording layer of the thermoplastic fine particle polymer type, the hydrophobic fine particle polymer is melted by heat generated by exposure and is fused to form a hydrophobic region, that is, an image portion.
As the fine particle polymer, those in which fine particles melt and coalesce with heat are preferable, and those having a hydrophilic surface and capable of being dispersed in a hydrophilic component such as dampening water are more preferable. Specifically, Research Disclosure No. 33303 (January 1992), JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, and JP-A-9-171250, and European Patent Application Publication No. 931,647. Preferred examples thereof include thermoplastic fine particle polymers. Of these, polystyrene and polymethyl methacrylate are preferred. Examples of the fine particle polymer having a hydrophilic surface include those in which the polymer itself is hydrophilic; those in which a hydrophilic compound such as polyvinyl alcohol and polyethylene glycol is adsorbed on the surface of the fine particle polymer to make the surface hydrophilic.
The fine particle polymer preferably has a reactive functional group.

  As a microcapsule type photosensitive composition, a compound having a heat-reactive functional group as described in JP-A No. 2000-118160 or JP-A No. 2001-277740 is included. A microcapsule type is preferable.

  Examples of the sulfonic acid generating polymer used in the sulfonic acid generating polymer-containing photosensitive composition include sulfonic acid ester groups, disulfone groups, and sec- or tert-sulfonamides described in JP-A No. 10-282672. Examples thereof include polymers having a group in the side chain.

  By incorporating a hydrophilic resin into the unprocessed photosensitive composition, not only on-press developability is improved, but also the film strength of the photosensitive layer itself is improved. Examples of the hydrophilic resin include those having a hydrophilic group such as hydroxy group, carboxy group, hydroxyethyl group, hydroxypropyl group, amino group, aminoethyl group, aminopropyl group, carboxymethyl group, and hydrophilic sol-gel conversion system. A binder resin is preferred.

  The unprocessed type image recording layer does not require a special development step and can be developed on a printing press. As a method for producing an unprocessed image recording layer and a plate-making printing method, methods described in detail in JP-A No. 2002-178655 can be used.

<Back coat>
In this way, the back surface of the lithographic printing plate precursor obtained by providing various image recording layers on the lithographic printing plate support of the present invention is scratched on the image recording layer when overlaid as necessary. In order to prevent this, a coating layer made of an organic polymer compound can be provided.

[Plate making method (lithographic printing plate production method)]
The lithographic printing plate precursor using the lithographic printing plate support of the present invention is converted into a lithographic printing plate by various treatment methods according to the image recording layer.
Examples of the actinic ray light source used for image exposure include a mercury lamp, a metal halide lamp, a xenon lamp, and a chemical lamp. Examples of the laser beam include helium-neon laser (He-Ne laser), argon laser, krypton laser, helium-cadmium laser, KrF excimer laser, semiconductor laser, YAG laser, and YAG-SHG laser.

After the above exposure, if the image recording layer is one of a thermal positive type, a thermal negative type, a conventional negative type, a conventional positive type, and a photopolymer type, it is exposed and then developed using a developer to obtain a lithographic printing plate. It is preferable to obtain.
The developer is preferably an alkaline developer, and more preferably an alkaline aqueous solution substantially free of an organic solvent.
Moreover, the developing solution which does not contain alkali metal silicate substantially is also preferable. As a method of developing using a developer substantially not containing an alkali metal silicate, a method described in detail in JP-A No. 11-109637 can be used.
A developer containing an alkali metal silicate can also be used.

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.
1-1. Production of aluminum alloy plate (Part 1)
Each component of the amount shown in Table 1 is contained, and the balance is continuously cast by a twin roll type continuous casting apparatus (manufactured by Hunter Engineering Co.) using an Al molten metal composed of Al and inevitable impurities. After performing the intermediate rolling and further performing the intermediate annealing under the conditions shown in Table 1, the thickness is adjusted to 0.3 mm by finish cold rolling, and the flatness is further corrected to obtain an aluminum alloy plate (Al plate). ) 1-14 were obtained. In addition, in the aluminum alloy plate 12, intermediate annealing was not performed.

1-2. Evaluation of aluminum alloy plate The aluminum alloy plates 1 to 14 obtained above were evaluated for the size and strength of crystal grains as follows.
(1) Size of crystal grains The surface of the aluminum alloy plate was buffed to give a mirror surface. The buffing was performed by performing a rough finish using an abrasive having a particle diameter of 1 μm, and then performing a finish using an abrasive having a particle diameter of 0.05 μm.
Subsequently, the surface of the buffed aluminum alloy plate was subjected to chemical etching for 45 seconds at room temperature using a hydrofluoric acid aqueous solution having a concentration of 10% by mass to visualize crystal grains.
Thereafter, a photograph of the crystal grains was taken at a photographic magnification of 15 times using a polarizing microscope (manufactured by Olympus), and the width (length in the direction perpendicular to the rolling direction) and length of the crystal grains in the obtained photograph ( The average value of the length in the rolling direction) was measured using image analysis software.
The results are shown in Table 2.

(2) Strength A sample was cut out from an aluminum alloy plate so as to have an effective width of 20 mm, a tensile test in the rolling direction was performed using an autograph (manufactured by Shimadzu Corporation), a stress at break was measured, and a tensile strength was measured. It was.
In addition, after performing a heat treatment at 270 ° C. for 7 minutes using a salt bath, a tensile test was performed in the same manner as described above, and the load when the permanent elongation was 0.2% was measured. % Proof stress.
The results are shown in Table 2.

1-3. Production of lithographic printing plate support (Examples 1 to 10 and Comparative Examples 1 to 4)
A first alkali etching treatment is performed on the surfaces of the aluminum alloy plates 1 to 14 obtained above using a sodium hydroxide aqueous solution having a concentration of 20% by mass and a temperature of 70 ° C., followed by an electrochemical surface roughening treatment. About 3 μm of the surface of the surface was dissolved, and 4 g / m ^{2 of the} opposite surface was dissolved. Thereafter, a first desmut treatment was performed using an aqueous nitric acid solution having a concentration of 1 mass% and a temperature of 35 ° C.
Then, using an aqueous nitric acid solution having a concentration of 7 g / L and a temperature of 35 ° C., an electrochemical rough surface so that the amount of electricity applied to the aluminum alloy plate during the anode reaction is 160 C / dm ² at an alternating current of 60.0 Hz. The chemical treatment was performed.
Then, the 2nd desmut process was performed using the sulfuric acid aqueous solution of density | concentration 25 mass% and temperature 60 degreeC, and the support body for lithographic printing plates was obtained.

1-4. Observation of surface of lithographic printing plate support The grain shape of the surface of the lithographic printing plate support obtained above was observed. Specifically, using a scanning electron microscope (T5500, manufactured by Hitachi Electronics Co., Ltd.), an SEM photograph was taken at a photographic magnification of 2000 times. Based on the SEM photograph, the pit uniformity on the surface of the lithographic printing plate support And surface unevenness (roughness seen on the surface due to crystal grains) was visually evaluated.
The uniformity of pits was evaluated according to the following five levels. If it is more than Δ, there is no practical problem.
○: The shape is round and uniform, the pit ridgeline is clear, and there is no unetched part (pit generation insufficient part) ○ △: The shape is slightly broken, but the shape is uniform and the pit ridgeline is slightly unclear △: The shape is round and uniform, and the pit ridgeline is clear, but the unetched portion exists. △ ×: The shape is broken, uneven, and the pit ridgeline is Unclear x: The shape is greatly collapsed, non-uniform, and there is no pit ridgeline. Also, surface irregularities were evaluated in five grades: ○, ○ △, △, △ ×, × from the side with less roughness. . If it is more than Δ, there is no practical problem.
The results are shown in Table 3.

As is apparent from Tables 2 and 3, the lithographic printing plate support (Examples 1 to 10) of the first aspect of the present invention has a crystal grain width and length in a suitable range, The pits are uniform and surface quality unevenness is suppressed. Among these, when the relationship between the Fe amount and the Si amount is in a suitable range (Examples 1 to 6), the pit uniformity is particularly excellent.
Further, since the lithographic printing plate support of the first aspect of the present invention (Examples 1 to 10) has a tensile strength and a 0.2% proof stress after heating within suitable ranges, the plate breaks during printing. Hard to occur.
On the other hand, when there was too much Cu amount (comparative example 1), the unetched part existed and the surface quality nonuniformity had generate | occur | produced. When the intermediate annealing was not performed (Comparative Example 2), the crystal grains were large and surface unevenness occurred. When the temperature of the intermediate annealing was too low (Comparative Example 3), crystal grains were large, pits were not uniform, and surface quality unevenness occurred. When the amounts of Fe and Si were too small (Comparative Example 4), the pits were not uniform and surface unevenness occurred.

2-1. Production of aluminum alloy sheet (Part 2)
(Examples 11-14)
Aluminum alloy plates (Al plates) 15 to 18 are obtained in the same manner as the aluminum alloy plates (Al plates) 1 to 4 except that the supply amount of rolling oil is reduced by 20% in the final cold rolling pass. It was.

  The obtained aluminum alloy plates 15 to 18 and “aluminum 1 to 4 and 11 to 14 obtained in preparation of aluminum alloy plate (Part 1) were subjected to the evaluation of the following aluminum alloy plates.

2-2. Production of lithographic printing plate support (Part 2)
(Examples 11-14)
By the method similar to Examples 1-10 and Comparative Examples 1-4, the 1st alkali etching process, the 1st desmut process, and the electrochemical roughening process were carried out to the surface of the aluminum alloy plates 15-18 obtained above. And the 2nd desmut process was performed and the support body for lithographic printing plates was obtained.

2-3. Evaluation of Support for Lithographic Printing Plate For the lithographic printing plate supports obtained in Examples 1 to 4 and 11 to 14 and Comparative Examples 1 to 4, an equal pitch pattern on the back surface and an average surface on the back surface are as follows. Roughness was evaluated.
(1) Equi-pitch pattern on the back side It was visually observed whether or not an equi-pitch pattern (protrusions with substantially equal intervals of 3 to 10 mm pitch parallel to the width direction) was present on the back side of the support for a lithographic printing plate. .
The results are shown in Table 4.

(2) Average surface roughness of the back surface The average surface roughness (R _a ) in the width direction and the rolling direction was measured for the back surface of the lithographic printing plate support. Measurement of the average surface roughness, stylus roughness meter (Surfcom575, manufactured by Tokyo Seimitsu Co., Ltd.) subjected to two-dimensional roughness measurement, the measured 5 times an average roughness R _a as defined in ISO4287, the average The value was the average surface roughness.
The results are shown in Table 4.

2-4. Production of lithographic printing plate precursors A lithographic printing plate support obtained in Examples 1 to 4 and 11 to 14 and Comparative Examples 1 to 4 is provided with a thermal positive type image recording layer as follows, and lithographic printing is performed. An original plate was produced.

<Hydrophilic treatment>
The lithographic printing plate support was hydrophilized. Specifically, the lithographic printing plate support was immersed in a 1% by weight aqueous solution of sodium silicate No. 3 (temperature 30 ° C.) for 10 seconds to perform alkali metal silicate treatment (silicate treatment). Then, the water washing by the spray using well water was performed. The amount of Si on the surface of the aluminum alloy plate measured with a fluorescent X-ray analyzer was 3.6 mg / m ² .

<Formation of undercoat layer>
Next, an undercoat layer was provided. Specifically, an undercoat solution having the following composition was applied onto a lithographic printing plate support after the alkali metal silicate treatment, and dried at 80 ° C. for 15 seconds to form a coating film of an undercoat layer. The coating amount of the coating film after drying was 15 mg / m ² .

<Undercoat liquid composition>
・ 0.3 g of a polymer represented by the following formula I
・ Methanol 100g
・ Water 1g

<Formation of image recording layer>
Further, a thermosensitive layer coating solution 1 having the following composition is applied to a lithographic printing plate support provided with an undercoat layer using a wire bar and dried at 140 ° C. for 50 seconds to form a lower layer of the image recording layer. I let you. The coating amount after drying of the lower layer (heat-sensitive layer coating amount) was 0.85 g / m ² . Subsequently, the heat-sensitive layer coating solution 2 having the following composition was applied using a wire bar and dried at 140 ° C. for 1 minute to form an upper layer of the image recording layer. The total coating amount after drying of the lower layer and the upper layer (coating amount of the heat-sensitive layer) was 1.1 g / m ² .
In this manner, a heat-sensitive layer (multi-layer type thermal positive type image recording layer) was formed to obtain a lithographic printing plate precursor.

<Composition of coating solution 1 for heat-sensitive layer>
N- (4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate (molar ratio 36/34/30, weight average molecular weight 50,000) 1.920 g
・ M, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 4000) 0.213 g
-0.032 g of cyanine dye A represented by the following formula A
・ 0.008 g of p-toluenesulfonic acid
・ Tetrahydrophthalic anhydride 0.19g
・ Bis-p-hydroxyphenylsulfone 0.126 g
・ 2-methoxy-4- (N-phenylamino) benzenediazonium ・ hexafluorophosphate 0.032 g
-0.078 g of a dye in which the counter anion of Victoria Pure Blue BOH is a 1-naphthalenesulfonic acid anion
・ Fluorine-based surfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.02g
・ Γ-butyrolactone 13.18g
・ Methyl ethyl ketone 25.41g
・ 1-methoxy-2-propanol 12.97g

<Composition of coating solution 2 for heat-sensitive layer>
-Phenol / m, p-cresol novolak (phenol / m / p ratio = 5/3/2, weight average molecular weight 4,000) 0.274 g
-Cyanine dye A represented by the above formula A 0.029 g
-0.14g of 30 mass% methyl ethyl ketone solution of the polymer represented by the following formula B
-Quaternary ammonium salt represented by the following formula C 0.004 g
・ Sulphonium salt represented by the following formula D 0.065 g
・ Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.004g
・ Fluorine-based surfactant (Megafac F-782, manufactured by Dainippon Ink & Chemicals, Inc.) 0.020 g
・ Methyl ethyl ketone 10.39g
・ 1-methoxy-2-propanol 20.98g

2-5. Evaluation of lithographic printing plate precursor The lithographic printing plate precursor obtained above was evaluated for interleaving paper separation property, conveyance belt conveyance property and nip roll conveyance property as follows.
(1) Interleaving paper separation From a state in which 40 lithographic printing plate precursors are laminated with a paper called interleaving paper sandwiched between them, first, a slip paper on the lithographic printing plate precursor is removed using a TrendSetter manufactured by Creo. Then, the sheet was adsorbed and removed by a slip-sheet adsorption type removing device, and then the lithographic printing plate precursor below was conveyed into the exposure device by a suction cup type conveying device. This operation was continuously performed for 10 lithographic printing plate precursors, and it was examined whether or not there was a problem that the next slip sheet under the lithographic printing plate precursor was conveyed together.
The results are shown in Table 4. The case where there was no defect in which the next slip sheet under the lithographic printing plate precursor was conveyed together was indicated by ○, and the case where there was a defect was indicated by ×.

(2) Conveyance of Conveying Belt Using a belt conveyability tester in which belts having a width of 50 mm (manufactured by Clarino Co., Ltd.) were arranged at intervals of 200 mm, the conveyability of the belt was examined. Specifically, 10 lithographic printing plate precursors were evaluated for the presence or absence of deviation in the direction of travel while the lithographic printing plate precursor moved 3 m.
The results are shown in Table 4. A case where the tip position of the lithographic printing plate precursor did not deviate by 2 mm or more in the direction perpendicular to the conveying direction was indicated by ◯, and a case where there was a deviation by 2 mm or more was indicated by x.
The results are shown in Table 4.

(3) Nip roll transportability A pair of rubber nip roll testers with a diameter of 30 mm was used to examine the transportability during nip. Specifically, 10 lithographic printing plate precursors were evaluated for the presence or absence of a shift in the traveling direction from when the lithographic printing plate precursor started to be sandwiched between nip rolls until it came out.
The results are shown in Table 4. The case where the tip position of the lithographic printing plate precursor did not deviate by 1 mm or more in the direction perpendicular to the conveying direction was indicated by ◯, and the case where there was a deviation by 1 mm or more was indicated by x.
The results are shown in Table 4.

As is apparent from Table 4, the lithographic printing plate support (Examples 1 to 4 and 11 to 14) of the second aspect of the present invention has interleaving paper separation properties, conveyance belt conveyance properties, and nip roll conveyance properties. Excellent. Among them, when the average surface roughness (R _a ) on the back surface is large (Example 4), the interleaf separation property is excellent. Also, if you have an equal pitch pattern on the back surface (Examples 11-14) also, although an equal pitch pattern itself is not the degree of pitch that affect average surface roughness (R _a), the average surface roughness (R _a) Excellent interleaving paper separation regardless of size.
On the other hand, when the average surface roughness ( _Ra ) of the back surface was too small (Comparative Examples 1 to 4), the interleaf separation property, the conveyance belt conveyance property, and the nip roll conveyance property were inferior.

3-1. Production of lithographic printing plate support (Part 3)
(Examples 15 and 16 and Comparative Examples 5 and 6)
Examples 1 to 10 and Comparative Examples 1 to 4 except that the concentration of the aqueous nitric acid solution used in the electrochemical roughening treatment was changed as shown in Table 5 on the surface of the aluminum alloy plate 1 obtained above. By the same method, the first alkali etching treatment, the first desmutting treatment, the electrochemical surface roughening treatment and the second desmutting treatment were carried out to obtain a lithographic printing plate support.

3-2. Observation of the surface of a lithographic printing plate support (Part 2)
The grain shape of the surface of the lithographic printing plate support obtained above was observed. Specifically, the pit uniformity and surface quality unevenness on the surface of the lithographic printing plate support were visually evaluated by the same method as described above.
The results are shown in Table 5.

As is apparent from Table 5, the lithographic printing plate support (Examples 15 and 16) of the first aspect of the present invention has uniform pits and suppressed surface quality unevenness.
On the other hand, when the concentration of nitric acid in the aqueous solution used for nitric acid electrolysis was too high (Comparative Examples 5 and 6), unetched portions existed or the pit uniformity was inferior, resulting in uneven surface quality.

Claims (5)

Fe: 0.10-0.40% by mass, Si: 0.03-0.12% by mass, Cu: 0.003% by mass or less, Ti: 0.001-0.02% by mass, the balance being An aluminum alloy plate made of Al and inevitable impurities, cast by a continuous casting method, and obtained by performing cold rolling, intermediate annealing at a temperature of 280 to 490 ° C., and finish cold rolling in this order, at least nitric acid A support for a lithographic printing plate obtained by performing a roughening treatment including an electrochemical roughening treatment using an aqueous solution containing
A lithographic printing plate support, wherein the aqueous solution has a nitric acid concentration of 10 g / L or less.   The aluminum alloy plate is Fe: 0.10 to 0.20 mass%, Si: 0.03 to 0.06 mass%, Cu: 0.003 mass% or less, Ti: 0.001 to 0.02 mass% The lithographic printing plate support according to claim 1, wherein the balance comprises Al and inevitable impurities.   The aluminum alloy plate is Fe: 0.24-0.36 mass%, Si: 0.06-0.10 mass%, Cu: 0.003 mass% or less, Ti: 0.001-0.02 mass% The lithographic printing plate support according to claim 1, wherein the balance comprises Al and inevitable impurities. Fe: 0.10-0.40% by mass, Si: 0.03-0.12% by mass, Cu: 0.003% by mass or less, Ti: 0.001-0.02% by mass, the balance being An aluminum alloy sheet made of Al and inevitable impurities, cast by a continuous casting method, and obtained by performing cold rolling, intermediate annealing at a temperature of 280 to 490 ° C., and finish cold rolling in this order, is at least rough. A support for a lithographic printing plate obtained by surface treatment,
The surface of the aluminum alloy plate opposite to the surface subjected to the roughening treatment is subjected to an alkali etching treatment with an aluminum dissolution amount of 1 to 10 g / m ² and an average surface roughness in the rolling direction. R _a is 0.15 to 0.35, the average surface roughness R _a in the direction perpendicular to the rolling direction is 0.20 to 0.40, the lithographic printing plate support.   On the surface of the aluminum alloy plate opposite to the surface subjected to the roughening treatment, a plurality of ridges having substantially equal intervals are formed in a direction perpendicular to the rolling direction. The lithographic printing plate support according to claim 4, wherein the distance is in the range of 3 to 10 mm.