JP4607692B2 - Method for producing support for lithographic printing plate - Google Patents

Description

  The present invention relates to a method for producing a lithographic printing plate support using an aluminum alloy plate.

As a method for producing an aluminum alloy plate, a slab obtained by casting a molten aluminum alloy by a semi-continuous casting method is subjected to homogenization heat treatment, followed by hot rolling, cold rolling, and annealing as necessary to obtain an aluminum alloy plate. Is generally adopted. On the other hand, various continuous casting methods have been proposed in which a molten aluminum alloy 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 rollers is 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 rollers are arranged vertically and an aluminum alloy plate is cast in the horizontal direction.
The method using these drive molds has the advantage that the equipment can be made compact. Among them, the method using a roll-shaped drive mold is excellent in that respect.

  In the method using a roll-shaped drive mold, molten aluminum alloy (hereinafter also referred to as “Al molten metal”) is supplied between a pair of cooling rollers via a molten metal supply nozzle, and the cooling roller causes the molten Al to solidify. Rolling is performed in one step. The method using a roll-shaped drive mold is specifically described in, for example, Patent Documents 1 to 6.

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

However, as a result of the study by the present inventors, when a support for a lithographic printing plate is produced using an aluminum alloy plate obtained by these methods, there arises a problem that surface treatment unevenness occurs on the surface and electrochemical roughening treatment. It has been found that there is a problem that uniformity is lowered.
Accordingly, an object of the present invention is to provide a method for producing a support for a lithographic printing plate which does not cause uneven surface treatment and is excellent in the uniformity of electrochemical surface roughening.

As a result of earnest research to achieve the above object, the present inventor has found that when the amount of aluminum dissolved in the alkali etching treatment increases, surface treatment unevenness of the surface is likely to occur, and this occurs in the continuous casting process. It has been found that non-uniformity such as coarsening of the crystal structure, segregation of additive elements, mixing of impurities and condensation is easily manifested by alkali etching treatment.
In addition, the present inventor is effective in preventing the surface treatment unevenness of the surface not to generate such non-uniformity in the continuous casting process, and even if non-uniformity occurs, the subsequent electrochemical It has been found that by improving the uniformity of the roughening treatment, it is possible to reduce surface treatment unevenness that has occurred.
Furthermore, in order to improve the uniformity of the electrochemical surface roughening treatment, the inventor controls the amounts of Fe, Si, and Cu elements in the Al molten metal within a specific range, and their It was found that it is important to control the amount of each element in the aluminum matrix within a specific range.
The present inventor has completed the present invention based on these findings.

According to a first aspect of the present invention, an aluminum alloy molten metal is supplied between a pair of cooling rollers via a molten metal supply nozzle, and rolled while the molten aluminum alloy is solidified by the pair of cooling rollers. Forming a continuous casting process;
A cold rolling step for reducing the thickness of the aluminum alloy plate obtained in the continuous casting step;
An intermediate annealing step of performing a heat treatment on the aluminum alloy plate in the cold rolling step;
A finish cold rolling step for reducing the thickness of the aluminum alloy sheet after the intermediate annealing;
The surface of the aluminum alloy plate after the finish cold rolling step is subjected to a roughening treatment including at least an alkali etching treatment and a subsequent electrochemical roughening treatment to obtain a lithographic printing plate support. A roughening treatment step,
The angle of the lower outer surface of the tip of the molten metal supply nozzle is an acute angle with respect to the discharge direction of the molten aluminum alloy, and among the members constituting the molten metal supply nozzle, the aluminum alloy An upper plate member that is in contact with the molten metal from the upper surface and a lower plate member that is in contact with the molten aluminum alloy from the lower surface are respectively movable in the vertical direction, and the upper plate member and the lower plate member are each of the aluminum alloy. A method for producing a support for a lithographic printing plate satisfying one or both of being pressed by the pressure of a molten metal and being pressed against the surface of the adjacent cooling roller,
The aluminum alloy melt contains 95% by mass or more of Al, 30 to 5000 ppm Fe, 300 to 2000 ppm Si, and 1 to 500 ppm Cu,
The finish cold said aluminum alloy plate after rolling, a solid solution amount of Fe 20ppm or more, a solid solution amount of Si is 20ppm or more state, and are dissolved amount Cu is more than 70 wt% of the total amount of Cu,
In the continuous casting process, the pair of cooling rollers is coated with a release agent containing carbon graphite on the surface thereof, and then a wiper is brought into contact with the surface of the cooling roller at a constant pressure to apply the release agent. Provided is a method for producing a support for a lithographic printing plate, in which the thickness of the mold is made uniform and the outer edge of the mouth of the molten metal supply nozzle does not contact the cooling roller or contacts only at the tip thereof.

According to a second aspect of the present invention, an aluminum alloy molten metal is supplied between a pair of cooling rollers via a molten metal supply nozzle, and rolled while the molten aluminum alloy is solidified by the pair of cooling rollers. Forming a continuous casting process;
A cold rolling step for reducing the thickness of the aluminum alloy plate obtained in the continuous casting step;
An intermediate annealing step of performing a heat treatment on the aluminum alloy plate in the cold rolling step;
A finish cold rolling step for reducing the thickness of the aluminum alloy sheet after the intermediate annealing;
The surface of the aluminum alloy plate after the finish cold rolling step is subjected to a roughening treatment including at least an alkali etching treatment and a subsequent electrochemical roughening treatment to obtain a lithographic printing plate support. A roughening treatment step,
A release agent containing aggregate particles having a particle size distribution with a median diameter of 5 to 20 μm and a mode diameter of 4 to 12 μm is applied in advance to the inner surface of the molten metal supply nozzle in contact with the molten aluminum alloy. A method for producing a lithographic printing plate support,
The aluminum alloy melt contains 95% by mass or more of Al, 30 to 5000 ppm Fe, 300 to 2000 ppm Si, and 1 to 500 ppm Cu,
The finish cold said aluminum alloy plate after rolling, a solid solution amount of Fe 20ppm or more, a solid solution amount of Si is 20ppm or more state, and are dissolved amount Cu is more than 70 wt% of the total amount of Cu,
In the continuous casting process, the pair of cooling rollers is coated with a release agent containing carbon graphite on the surface thereof, and then a wiper is brought into contact with the surface of the cooling roller at a constant pressure to apply the release agent. Provided is a method for producing a support for a lithographic printing plate, in which the thickness of the mold is made uniform and the outer edge of the mouth of the molten metal supply nozzle does not contact the cooling roller or contacts only at the tip thereof.

According to a third aspect of the present invention, an aluminum alloy molten metal is supplied between a pair of cooling rollers via a molten metal supply nozzle, and the aluminum alloy molten metal is rolled and solidified by the pair of cooling rollers. Forming a continuous casting process;
A cold rolling step for reducing the thickness of the aluminum alloy plate obtained in the continuous casting step;
An intermediate annealing step of performing a heat treatment on the aluminum alloy plate in the cold rolling step;
A finish cold rolling step for reducing the thickness of the aluminum alloy sheet after the intermediate annealing;
The surface of the aluminum alloy plate after the finish cold rolling step is subjected to a roughening treatment including at least an alkali etching treatment and a subsequent electrochemical roughening treatment to obtain a lithographic printing plate support. A roughening treatment step,
In the continuous casting process, the pair of cooling rollers is coated with a release agent containing carbon graphite on the surface thereof, and then a wiper is brought into contact with the surface of the cooling roller at a constant pressure to apply the release agent. A method for producing a support for a lithographic printing plate, wherein the thickness of the mold is made uniform, and the outer edge of the mouth of the molten metal supply nozzle does not contact the cooling roller or contacts only at the tip thereof,
The aluminum alloy melt contains 95% by mass or more of Al, 30 to 5000 ppm Fe, 300 to 2000 ppm Si, and 1 to 500 ppm Cu,
The support for a lithographic printing plate, wherein the aluminum alloy sheet after the finish cold rolling has a solid solution Fe amount of 20 ppm or more, a solid solution Si amount of 20 ppm or more, and a solid solution Cu amount of 70% by mass or more of the total Cu amount. A method for manufacturing a body is provided.

The method for producing a lithographic printing plate support of the present invention may correspond to two or more of the first to third aspects. Among these, it is preferable to correspond to any of the first to third aspects.

  According to the present invention, there can be obtained a lithographic printing plate support having no surface treatment unevenness and having excellent electrochemical surface roughening treatment uniformity.

  Hereinafter, the method for producing a lithographic printing plate support of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings. Since the first to fourth aspects of the method for producing a lithographic printing plate support of the present invention have common steps, they will be described simultaneously.

[Method for producing support for lithographic printing plate]
<Continuous casting process>
In the method for producing a lithographic printing plate support of the present invention, first, a continuous casting step is performed. The continuous casting step is a step of supplying an aluminum alloy molten metal between a pair of cooling rollers via a molten metal supply nozzle, and rolling the aluminum alloy molten metal with the pair of cooling rollers to form an aluminum alloy plate. It is.

<Al molten metal>
The Al molten metal used in the continuous casting process contains 95% by mass or more of Al, 30 to 5000 ppm of Fe, 300 to 2000 ppm of Si, and 1 to 500 ppm of Cu.

<Si>
Si is an element contained as an inevitable impurity in an Al ingot, which is a raw material of the Al molten metal, in an amount of about 300 to 1000 ppm. In many cases, Si is intentionally added in a small amount to prevent variation due to a difference in raw materials. A part of the added amount is dissolved in Al.
In the present invention, the amount of Si in the molten Al is 300 to 2000 ppm. In general, the stability of the electrochemical roughening treatment can be improved by setting the Si amount to a certain value or more. However, in the present invention, the lower limit of the Cu solid solution amount is set according to the total Cu amount. Even with a small amount of Si solid solution, the uniformity of the electrochemical surface roughening treatment is excellent. In the present invention, the amount of Si is 300 ppm or more, preferably 500 ppm or more.
If the amount of Si is too large, it becomes easier to form a compound with Fe, which affects the amount of solid solution of Fe. In addition, if the amount of Si is too large, the amount of single Si increases, and when anodizing is performed after the surface roughening treatment, defects in the anodized film are likely to occur due to the single Si, and water retention of the defective portion Inferior, and the paper is easily smeared during printing. Therefore, in the present invention, the Si content is 2000 ppm or less, preferably 1500 ppm or less.

<Fe>
Fe has an effect of increasing the mechanical strength of the aluminum alloy, and greatly affects the strength of the support. In particular, the effect of improving the heat softening property is great. Further, it has been conventionally considered that there is not much influence on the electrochemical surface roughening treatment, but if the amount of Fe solid solution is too small, it may show a problem that the pits generated by the electrochemical surface roughening treatment are deformed. is there.
In the present invention, the amount of Fe is 30 ppm or more, preferably 1000 ppm or more. As a result, the pits generated by the electrochemical surface roughening treatment become uniform, and the heat softening resistance is excellent.
Conventionally, it has been pointed out that if the amount of Fe is too large, the strength becomes unnecessarily high, and when attaching a lithographic printing plate to the plate cylinder of a printing press, it is inferior in fitness and tends to cause plate breakage during printing. However, the present inventor has found that it is effective to make it 5000 ppm or less from the viewpoint of making the uniformity of the electrochemical roughening treatment excellent. This is because if the amount of Fe is large, an intermetallic compound containing Fe drops during the surface roughening treatment, and the uniformity of the electrochemical surface roughening treatment decreases.
In the present invention, the Fe content is 5000 ppm or less, preferably 4000 ppm or less.

<Cu>
Cu is an important element in controlling the electrochemical surface roughening treatment. Cu is an element that is very easily dissolved, and part of it is an intermetallic compound. In the present invention, the Cu content is set to 1 ppm or more, preferably 10 ppm or more, in order to make the electrochemical surface roughening process more uniform in the above-described Fe content and Si content ranges.
If the amount of Cu is too large, the diameter of the pits generated by the electrochemical surface roughening treatment in the nitric acid solution becomes too large, and the uniformity of the diameter decreases, so that the stain resistance is particularly poor.
The present inventors can make pits having a diameter of 0.5 μm or less generated by electrochemical surface roughening treatment in a hydrochloric acid-containing liquid by making the amount of Cu in a specific range, and a support. It has been found that the rate of increase in surface area can be increased. Since the contact area with the image recording layer can be increased by increasing the surface area increase rate, the adhesion between the support and the image recording layer is improved, and the printing durability and cleaner printing durability are excellent. It becomes. Further, the stain resistance when the planographic printing plate is obtained is excellent.
In the present invention, the amount of Cu is 500 ppm or less, preferably 350 ppm or less.

The molten Al can contain an element for refining crystal grains in order to prevent cracking during casting. For example, Ti can be contained in a range of 500 ppm or less. Moreover, B can be contained in the range of 200 ppm or less.
Specifically, it is preferable to add a master alloy containing TiB ₂ to the molten Al. Thereby, the crystal grain at the time of continuous casting tends to become fine, and when it is used as a lithographic printing plate support, it is possible to suppress the occurrence of surface treatment unevenness due to coarse crystal grains in the surface treatment step. 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. However, TiB ₂ alone is usually a very small particle of 1 to 2 μm, but may aggregate to become a coarse particle of 100 μm or more, and in that case, the coarse particle causes the 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 molten Al is made of Al and inevitable impurities. Examples of inevitable impurities include Mg, Mn, Zn, Cr, Zr, V, Zn, and Be. Each of these can be contained in a range of 500 ppm 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, L.A. F. The amount of impurities described in Mondolfo's “Aluminum Alloys: Structure properties” (1976) and the like may be contained.

<Cleaning process>
The Al melt is prepared to contain 95% by mass or more of Al, 30 to 5000 ppm Fe, 300 to 2000 ppm Si, and 1 to 500 ppm Cu, and then 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.

<Filtration process>
In the 1st aspect of this invention, the filtration process which filters the said aluminum alloy molten metal using a filter tank is performed before the said continuous casting process. In the second to fourth aspects of the present invention, this filtration step is preferably performed. 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 first aspect of 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. Stirring means provided in a recess formed on the bottom surface stirs the molten aluminum alloy. In the second to fourth aspects of the present invention, when a filtration step is performed, it is preferable to perform this supply step and perform such agitation. 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.

FIG. 1 is a schematic diagram illustrating an example of a configuration from a melting furnace to a casting apparatus.
In the melting furnace 12, the Al metal is melted and Fe, Si and Cu are added to obtain an Al molten metal having a desired composition. As a method for adding Fe, Si and Cu, for example, an Al—Fe (25 mass%) master alloy, an Al—Si (25 mass%) master alloy, an Al—Cu (25 mass%) master alloy, etc. The method of adding is mentioned.
The molten Al 22 held in the melting furnace 12 is supplied to the molten metal supply nozzle 16 of the casting apparatus 10 via the flow path 14. A recess 30 is formed on the bottom surface in the middle of the flow path 14, and a gas discharge part 43 is provided in the recess 30 as a stirring means.

FIG. 2 is a schematic diagram showing an example of a recess provided with stirring means.
When casting is continued for a long time, impurities having a large specific gravity settle on the bottom of the concave portion 30 and TiB ₂ particles in the Al molten metal are trapped in the upper portion of the concave portion 30 and are likely to be primarily retained. Further, as the casting continues for a long time, the amount of TiB ₂ that stays increases, so that the aggregation of TiB ₂ easily occurs. Therefore, as shown in FIG. 2, a gas that does not react with the Al molten metal 22 such as argon gas is discharged as fine bubbles 46 from the gas discharge portion 43 made of a porous material such as ceramic into the recess 30, and the inside of the recess 30. The molten Al 22 is stirred. This prevents stagnation from occurring.
FIG. 3 is a schematic view showing another example of a recess provided with stirring means. As shown in FIG. 3, a gas that does not react with the molten Al 22 such as argon gas is released as fine bubbles 46 from the rotary rotor 45 to the concave portion 30, and the molten Al 22 in the concave portion 30 is stirred. This prevents stagnation from occurring.
These are described in detail in JP-A No. 2000-24762.
Since the retention during casting for a long time may occur in all of the recesses where stagnation is likely to occur, this stirring means is preferably performed in the recesses immediately before the molten metal supply nozzle.

<Melting nozzle>
The molten Al discharged from the molten metal supply nozzle comes into contact with the surface of the cooling roller 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 roller, a meniscus of the molten Al is formed. When the meniscus vibrates, the contact point with the cooling roller 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.
In the second aspect of the present invention, the angle of the lower outer surface of the tip of the molten metal supply nozzle is an acute angle with respect to the discharge direction of the molten aluminum alloy, and the molten metal supply nozzle Among the members constituting the upper plate member that contacts the molten aluminum alloy from the upper surface and the lower plate member that contacts the molten aluminum alloy from the lower surface are respectively movable in the vertical direction, the upper plate member and the Each of the lower plate members is pressed by the pressure of the molten aluminum alloy and satisfies one or both of being pressed against the surface of the adjacent cooling roller. In the first, third and fourth aspects of the present invention, it is preferable to satisfy one or both of the above.
When the angle of the lower outer surface of the tip of the molten metal supply nozzle is an acute angle with respect to the discharge direction of the molten aluminum alloy, the position where the Al molten metal is detached from the tip of the nozzle is stabilized in one place. Easy to reduce the ripple mark. For example, the method described in JP-A-10-58094 can be preferably used.
Moreover, it is more preferable that the angle of the upper outer surface of the tip of the molten metal supply nozzle is an acute angle with respect to the discharge direction of the molten aluminum alloy.

  Also, the shape of the molten metal supply nozzle is preferably such that the outer edge of the mouth is in contact with the cooling roller, and the escape portion that avoids contact with the cooling roller is recessed on the outer periphery of the mouth of the molten metal supply nozzle. One. Such a configuration is preferable in that only the tip of the melt supply nozzle is always in contact with the cooling roller, and the stability of the melt at the tip is increased.

FIG. 5 is a schematic diagram illustrating a preferred example of the shape of the molten metal supply nozzle and the positional relationship with the cooling roller. In FIG. 5, only the nozzle plate and the cooling roller on the upper end side of the nozzle are shown, but the nozzle plate and the cooling roller on the lower end side of the nozzle have the same positional relationship.
In FIG. 5, the outer edge of the mouth of the molten metal supply nozzle 16 contacts the cooling roller 18, and an escape portion (chamfered portion) 8 that avoids contact with the cooling roller 18 is recessed on the outer periphery of the molten metal supply nozzle 16. Yes. That is, the molten metal supply nozzle 16 is in contact with the cooling roller 18 only at the tip portion T. The escape portion (chamfered portion) is preferably provided over the entire width of the molten metal supply nozzle 16.
By adopting such a structure, there is no gap as a space where the molten metal meniscus portion fluctuates, so that an aluminum alloy plate that does not cause an appearance failure can be obtained, and for lithographic printing plates in which the appearance failure is further suppressed. A support can be obtained.

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 roller. Therefore, ideally, the tip of the nozzle whose cooling surface is always in contact with the above-described lower (preferably lower and upper) outer surface angle is always acute with respect to the discharge direction of the molten metal. The state which is doing 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, the upper plate member and the lower plate member are each pressed by the pressure of the molten Al and pressed against the surface of the adjacent cooling roller. 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 roller, and as a result, the shape of the molten metal meniscus is maintained in a constant state, so that the appearance failure such as ripple marks is further suppressed. You can get a body.

FIG. 6 is a schematic view showing another example of the molten metal supply nozzle having a movable tip. FIG. 6A is a plan view, and FIG. 6B is a side view.
The molten metal supply nozzle 16B shown in FIG. 6 fixes the upper plate member 40 and the lower plate member 42 with the bar member 92, so that the tips of the upper plate member 40 and the lower plate member 42 have the bar member 92 as a fulcrum. It can move slightly according to the pressure of the molten Al. Therefore, the tips of the upper plate member 40 and the lower plate member 42 can be brought into contact with the cooling roller by the pressure of the molten Al, respectively.

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. Moreover, it is necessary to prevent the Al molten metal from partially solidifying in the molten metal supply nozzle. 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 rollers is as small as about several mm to 10 mm, the nozzle for supplying the molten metal 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 molten Al in the nozzle, it is preferable that the inner surface of the nozzle has low wettability with the molten Al. For this purpose, it is preferable that the inner surface of the nozzle is made of a material having low wettability with respect to the molten Al and has appropriate unevenness. Japanese Patent Application Laid-Open No. 10-225750 describes a method for defining the roughness of the nozzle inner surface.
Specifically, in the third aspect of the present invention, 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 molten aluminum alloy. A release agent containing aggregate particles having a particle size distribution is applied. In the first, second and fourth aspects of the present invention, it is preferable to apply such a release agent. 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 roller>
A cooling roller is not specifically limited, For example, conventionally well-known things, such as an iron core-shell structure cooling roller, can be used. When using a cooling roller having a core / shell structure, the cooling ability of the surface of the cooling roller can be enhanced 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 cooling roller is left as it is, it is likely to adhere to the cooling roller, and it may not be easy to cast stably and continuously. Therefore, in the fourth aspect of the present invention, a release agent is applied to the surfaces of the pair of cooling rollers. In the first to third aspects of the present invention, a release agent is preferably applied. 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 preferable in that the release agent can be supplied in a non-contact manner to the cooling roller.

Here, if the thickness of the applied release agent is different in the width direction and / or the circumferential direction of the cooling roller, the speed of heat transfer to the cooling roller is affected, leading to nonuniform crystal grains. In the fourth aspect of the present invention, the thickness of the applied release agent is made uniform. In the first to third aspects of the present invention, when the release agent is applied to the surface of the pair of cooling rollers, 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 roller at a constant pressure is preferably exemplified. 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.

  The release agent is preferably supplied to the surface of the cooling roller periodically in order to be captured by a homogenizing means such as a wiper or to move to the surface of a continuously cast aluminum alloy plate.

In addition, if the molten metal supply nozzle contacts the cooling roller in the width direction unevenly, the release agent on the surface of the cooling roller 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.
Accordingly, in the fourth aspect of the present invention, the outer edge of the mouth of the molten metal supply nozzle does not contact the cooling roller or contacts only at the tip thereof. In the first to third aspects of the present invention, it is preferable that the outer edge of the mouth of the molten metal supply nozzle does not contact the cooling roller or contacts only at the tip thereof.
Among these, it is more preferable to make contact only at the tip in terms of reducing the ripple mark.

<Casting>
Casting is performed by supplying the Al molten metal between a pair of cooling rollers via the molten metal supply nozzle, and rolling the Al molten metal with the pair of cooling rollers to form an aluminum alloy plate.
As shown in FIG. 1, in the casting apparatus 10, the Al molten metal 22 is supplied between the pair of cooling rollers 18 via the molten metal supply nozzle 16. The molten aluminum 22 is solidified and rolled by the cooling roller 18 to form an aluminum alloy plate 36. The thickness of the obtained aluminum alloy plate 36 is preferably thinner in terms of the efficiency of cold rolling, and is usually 1 to 10 mm.

  FIG. 4 is a schematic diagram illustrating an example of a positional relationship among the cooling roller, the molten metal supply nozzle, the aluminum alloy plate, the Al molten metal, and the molten meniscus portion. In FIG. 4, the Al molten metal 22 passes through the molten metal supply nozzle 16 composed of a pair of nozzle plates 4 a and 4 b and a side plate (not shown), and is provided with a clearance C and rotates in the direction of the arrow V. An aluminum alloy plate is cast between the pair of cooling rollers 18 of D and in the direction of arrow a. The Al molten metal 22 has a curvature corresponding to the diameter of the nozzle outlet and the cooling roller, and the upper and lower surfaces spread in the vertical direction in the defined gap to form the molten meniscus portion 3. In the Al molten metal 22 in contact with the cooling roller 18, heat moves toward the center of each of the pair of cooling rollers 18, so that a crystal structure grows in the same direction as the heat transfer. Further, the thickness t of the cast aluminum alloy plate is a value substantially equal to the clearance C of the cooling roller 18 or a value obtained by adding the elastic deformation of the casting apparatus and the aluminum alloy plate to the clearance C.

<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.
FIG. 7 is a schematic diagram showing an example of a cold rolling mill used for cold rolling. The cold rolling mill 50 shown in FIG. 7 applies pressure to the aluminum alloy plate 36 conveyed between the feeding coil 52 and the winding coil 54 by a pair of rolling rollers 56 that are respectively rotated by support rollers 58. And cold rolling.

<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. In the intermediate annealing step, the solid solution amount of each element of Fe, Si and Cu in the aluminum alloy plate is controlled. Details will be described below.
Originally, the continuous casting process can cool and solidify aluminum very rapidly, unlike the conventional method using a fixed mold. As a result, the solid solution amount of each element of Fe, Si, and Cu in the aluminum alloy plate obtained through continuous casting is increased as compared with the conventional method using a fixed mold. In addition, the size of the intermetallic compound precipitated in the aluminum alloy plate obtained through continuous casting is smaller than that of a conventional method using a fixed mold.
On the other hand, when heated for a long time in the intermediate annealing step, each element once dissolved may precipitate, and the amount of the solid solution may be drastically reduced. As a result, it becomes impossible to secure a predetermined amount of solid solution, which will be described later, and the surface shape generated by the electrochemical surface roughening treatment becomes extremely unstable and non-uniform, resulting in non-uniformity of the aluminum alloy plate after the surface treatment. It may not be possible to suppress uneven surface treatment. Furthermore, if the surface shape becomes unstable or non-uniform, the printing performance also decreases.

As described above, in the present invention, various methods for suppressing surface treatment unevenness can be used in the continuous casting process.
However, with these methods alone, the crystal structure before the roughening treatment described later appears to be uniform, but after the roughening treatment, an uneven history of the crystal structure is likely to be manifested, especially when the amount of alkali etching is large. It was.
In the present invention, in the continuous casting process of an aluminum alloy plate, a method for suppressing various non-uniformities that cause surface treatment unevenness is used. In addition, in the intermediate annealing process, each element of Fe, Si, and Cu is used. By controlling the solid solution amount, the uniformity in the electrochemical surface roughening treatment described later is made excellent, and it is possible to suppress the occurrence of surface treatment unevenness due to the manufacturing process of the aluminum alloy plate. .

  In this invention, it is one of the preferable aspects that an intermediate annealing process is performed at the temperature of 300-560 degreeC for 2 to 20 hours by a batch annealing system. Thereby, suppression of precipitation of each dissolved element and re-solution of each precipitated element are promoted. As a result, the solid solution amount of each element is ensured. Moreover, in order to prevent the coarsening of a crystal grain, it is preferable that the temperature of the intermediate annealing process of this aspect is 560 degrees C or less, and it is preferable that time is 20 hours or less.

  Moreover, it is one of another preferable aspects that an intermediate annealing process is performed by the continuous annealing system at the temperature of 500-600 degreeC for 1 second-5 minutes. Thereby, suppression of precipitation of each dissolved element and re-solution of each precipitated element are promoted. As a result, the solid solution amount of each element is ensured. Moreover, in order to prevent the coarsening of a crystal grain, it is preferable that the temperature of the intermediate annealing process of this aspect is 600 degrees C or less, and it is preferable that time is 5 minutes or less.

<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.

In the present invention, the aluminum alloy sheet after the finish cold rolling step has a solid solution Fe amount of 20 ppm or more, a solid solution Si amount of 20 ppm or more, and a solid solution Cu amount of 70% by mass or more of the total Cu amount. As described above, the solid solution amount of each element of Fe, Si, and Cu can be performed by the intermediate annealing step.
When the solid solution amount of each element of Fe, Si and Cu is within the above range, the uniformity of the electrochemical surface roughening treatment is excellent. The amount of solid solution Fe is preferably 25 ppm or more. The amount of dissolved Si is preferably 50 ppm or more. The amount of solid solution Cu is preferably 70% by mass or more of the total amount of Cu. Moreover, it is preferable that the amount of solid solution Cu is 100 ppm or more, and it is preferable that it is 500 ppm or less.

<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.

  FIG. 8 is a schematic diagram illustrating an example of a correction device. The straightening device 70 shown in FIG. 8 improves the flatness while applying tension to the aluminum alloy plate 36 conveyed between the feeding coil 82 and the winding coil 84 at the leveler unit 80 including the work roll 86. . Thereafter, the sheet width is adjusted to a predetermined width by the slitter 88.

<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.

<Roughening treatment process>
After the finish cold rolling process, after performing a flatness correction process and / or a slit process as desired, a roughening process process is performed. In the roughening treatment step, the surface of the aluminum alloy plate after the finish cold rolling step is subjected to a roughening treatment including at least an alkali etching treatment and a subsequent electrochemical roughening treatment to obtain a planographic printing plate. It is the process of obtaining the support body for use.
As the roughening treatment, generally one or a combination of two or more of mechanical roughening treatment, chemical roughening treatment and electrochemical roughening treatment is used.
In the present invention, two processes of an alkali etching process and a subsequent electrochemical surface roughening process are essential as the surface roughening process, but other processes may be included.
Hereinafter, various processes that can be included in the roughening process will be described.

<Mechanical roughening>
The mechanical roughening treatment is usually performed for the purpose of setting the surface of the aluminum alloy plate to an average surface roughness of 0.35 to 1.0 μm. As the mechanical roughening treatment, for example, methods described in JP-A-6-135175 and JP-B-50-40047 can be used. The mechanical surface roughening treatment is preferably performed before the electrochemical surface roughening treatment (or the first electrochemical surface roughening treatment when the electrochemical surface roughening treatment is performed a plurality of times).
As the mechanical roughening treatment, a method using a rotating nylon brush roll having a bristle diameter of 0.2 to 0.9 mm and a slurry of an abrasive supplied to the surface of the aluminum alloy plate is preferable. Moreover, the system which sprays a slurry liquid and the system using a wire brush can also be used. Moreover, the system which transfers the surface shape of the rolling roll which provided the unevenness | corrugation to an aluminum alloy plate can also be used. This method is superior to a method using a brush or an abrasive in that a locally deep portion is hardly generated.
In addition, when making average surface roughness into less than 0.35 micrometer, a mechanical roughening process is not normally performed.

<Chemical etching process>
The chemical etching process is a process of chemically etching the surface of the aluminum alloy plate in an alkaline aqueous solution or an acidic aqueous solution. In the present invention, an alkali etching process using an aqueous alkali solution having excellent dissolution efficiency is performed. As the alkali etching treatment, a conventionally known method can be used. In the present invention, an alkali etching treatment is performed before the first electrochemical surface roughening treatment.
The alkali etching treatment is performed for the purpose of obtaining a surface having smooth undulations by dissolving the uneven edge portions generated by the mechanical roughening treatment described above. As a result, a lithographic printing plate having excellent stain resistance can be obtained.
Further, the alkali etching treatment is performed for the purpose of removing foreign matters such as rolling oil remaining on the surface of the aluminum alloy plate when the mechanical surface roughening treatment is not performed.

Examples of the alkaline aqueous solution used for the alkali etching treatment include an aqueous solution containing one or more of caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide and the like. . In particular, an aqueous solution mainly composed of sodium hydroxide (caustic soda) is preferable. The alkaline aqueous solution may contain 0.5 to 10% by mass of alloy components contained in the aluminum alloy plate as well as aluminum.
The concentration of the alkaline aqueous solution is preferably 1 to 50% by mass, and more preferably 1 to 30% by mass.
The alkaline etching treatment is performed by treating the aqueous alkali solution at a temperature of preferably 20 to 100 ° C., more preferably 40 to 80 ° C., preferably 1 to 120 seconds, more preferably 2 to 60 seconds.

The amount of aluminum dissolved in the alkali etching treatment after the mechanical surface roughening treatment is preferably 1 to ²⁰ g / m ² on the surface subjected to the surface roughening treatment. Excessive alkali etching treatment is not preferable because it tends to cause surface treatment unevenness due to the mother crystal in which the aluminum alloy plate is present, and therefore, the aluminum dissolution amount is preferably 1 to 13 g / m ² . More preferably from 2 to 13 g / m ^2.
When the mechanical surface roughening treatment is not performed, the aluminum dissolution amount is preferably ¹ to 6 g / m ² on the surface subjected to the surface roughening treatment.
As described above, it is possible to completely remove impurities in the vicinity of the surface layer of the aluminum alloy plate by setting the aluminum dissolution amount to 1 g / m ² or more on the surface of the aluminum alloy plate subjected to the roughening treatment. And uniform electrochemical roughening treatment can be performed.
The amount of aluminum dissolved on the surface of the aluminum alloy plate not subjected to the roughening treatment, that is, the back surface, is preferably 1 g / m ² or more.

<Electrochemical roughening treatment>
The electrochemical roughening treatment is a treatment for electrochemically roughening the surface of the aluminum alloy plate through an alternating current or a direct current using an aluminum alloy plate as an electrode in an acidic aqueous solution. A conventionally well-known method can be used as an electrochemical roughening process.
The electrochemical surface roughening treatment is performed for the purpose of generating crater-like or honeycomb-like pits having an average diameter of about 0.05 to 20 μm on the surface of the aluminum alloy plate at an area ratio of 30 to 100%. By the electrochemical surface roughening treatment, the stain resistance (dirt resistance) and the printing durability of the non-image area of the planographic printing plate are improved.

As the acidic aqueous solution used for the electrochemical surface roughening treatment, those used for the electrochemical surface roughening treatment using a normal alternating current or direct current can be used. Among these, an acidic aqueous solution containing nitric acid or an acidic aqueous solution containing hydrochloric acid is preferable.
As the acidic aqueous solution containing nitric acid, for example, at least one nitric acid compound having nitric acid ions such as aluminum nitrate, sodium nitrate, and ammonium nitrate is added from 0.01 g / L to an aqueous nitric acid solution having a nitric acid concentration of 1 to 100 g / L. It can be added and used at a concentration up to saturation. In the acidic aqueous solution containing nitric acid, a metal contained in an aluminum alloy such as iron, copper, manganese, nickel, titanium, magnesium, or silicon may be dissolved.

Examples of the acidic aqueous solution containing hydrochloric acid include 0.01 g / L of at least one hydrochloric acid compound having hydrochloric acid ions such as aluminum chloride, sodium chloride, and ammonium chloride in an aqueous hydrochloric acid solution having a hydrochloric acid concentration of 1 to 100 g / L. Can be added and used at a concentration from saturation to saturation. In the acidic aqueous solution containing hydrochloric acid, a metal contained in an aluminum alloy such as iron, copper, manganese, nickel, titanium, magnesium, or silicon may be dissolved.
After performing an electrochemical roughening treatment mainly composed of nitric acid, an alkali etching treatment and a desmut treatment are performed, and an electrochemical roughening treatment mainly comprising hydrochloric acid is performed as a second electrochemical roughening treatment. You may go.

  As described above, when the amount of aluminum dissolved in the alkali etching treatment is large, the total amount of electricity during the anode reaction in the electrochemical surface roughening treatment is increased to increase the total amount of electricity for the lithographic printing plate caused by the mother crystal generated during casting. Unevenness of surface treatment of the support can be prevented. Moreover, if the total amount of electricity during the anode reaction in the electrochemical surface roughening treatment is too large, the effect of reducing the surface treatment unevenness of the surface is reduced, but the effect is increased by setting the above range. be able to.

Further, the electrochemical surface roughening treatment can be a combination of two or more treatments. For example, first, the first electrochemical surface roughening treatment is performed using an electrolytic solution mainly containing nitric acid, then alkali etching and desmutting are performed, and then the second electrolytic solution containing mainly hydrochloric acid is used. The electrochemical surface roughening treatment may be performed. In this case, a finer concavo-convex structure formed by the second electrochemical roughening process can be superimposed on the concavo-convex formed by the first electrochemical roughening process.
Similarly, both the first and second electrochemical roughening treatments use hydrochloric acid, and the conditions are changed. Similarly, the second electric surface is formed inside the irregularities formed by the first electrochemical roughening treatment. A finer concavo-convex structure formed by chemical roughening treatment can also be superimposed.
In any case, the second electrochemical surface roughening treatment is preferably performed using hydrochloric acid so that the total amount of electricity during the anode reaction on the surface is 30 to 80 C / dm ² or more.

  Between the first and second electrochemical surface roughening treatments, it is preferable to sandwich alkali etching and desmutting as described above, but they may be omitted.

The total amount of electricity during the anode reaction on the surface of the aluminum alloy plate subjected to the surface roughening treatment in the electrochemical surface roughening treatment is preferably 50 C / dm ² or more. Within the above range, it is possible to more reliably suppress the occurrence of surface treatment unevenness on the surface of the lithographic printing plate support.
The average current density during the anode reaction in the electrochemical surface roughening treatment is preferably 5 A / dm ² or more. Within the above range, the dispersibility of the pits in the electrochemical surface roughening process is good.

<Electropolishing treatment or second chemical etching treatment>
The electropolishing process is an electrolysis process using an aluminum alloy plate as an electrode in an acidic aqueous solution. As the electropolishing treatment, a conventionally known method can be used.
The electrolytic polishing process or the second chemical etching process is performed by removing the smut component mainly composed of aluminum hydroxide generated by the above-described electrochemical surface roughening process, and smoothing the edge portion of the generated pit. It is carried out for the purpose of improving the stain resistance when used as a printing plate.
Dissolution of the aluminum alloy plate in electropolishing treatment or second chemical etching treatment is preferably 0.05-5 g / m ^2, and more preferably 0.1 to 3 g / m ^2.
After the first and second and subsequent alkali etching treatments, desmut treatment using an acidic solution is preferably performed.

<Anodizing process>
In the present invention, it is preferable to perform an anodizing treatment step after the roughening treatment step. The anodizing treatment is performed to increase the wear resistance of the surface of the aluminum alloy plate.
The anodizing treatment can be performed by a method conventionally used in this field. For example, an anodized film can be formed by energizing an aluminum plate as an anode in a solution having a sulfuric acid concentration of 50 to 300 g / L and an aluminum concentration of 5% by mass or less. The solution used for the anodizing treatment is not particularly limited as long as it can form an oxide film on the aluminum alloy plate, and examples thereof include sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixture thereof. . The concentration of the electrolyte is appropriately determined depending on the type of the electrolyte.
The conditions of the anodizing treatment cannot be determined unconditionally because they vary depending on the electrolytic solution used. In general, the electrolytic solution concentration is 1 to 80% by mass, the liquid temperature is 5 to 70 ° C., and the current density is 1 to 60 A. / Dm ² , a voltage of 1 to 100 V, and an electrolysis time of 10 to 300 seconds are appropriate and adjusted so as to obtain a desired anodic oxide film amount.

<Hydrophilic treatment process>
In the present invention, it is preferable to perform a hydrophilization treatment step after the anodization treatment step. The hydrophilic treatment is a treatment for making the surface of the lithographic printing plate support hydrophilic.
The hydrophilization treatment is described in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734, and 3,902,734. There are alkali metal silicate (eg, aqueous sodium silicate) methods. In this method, an aluminum alloy plate is immersed in an aqueous sodium silicate solution or electrolytically treated.
Further, potassium fluoride zirconate described in Japanese Patent Publication No. 36-22063, and U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689,272. A method of treatment with polyvinylphosphonic acid as described in each specification can also be used.

[Lithographic printing plate precursor]
The lithographic printing plate support obtained as described above is provided with an image recording layer to form a lithographic printing plate precursor.
The image recording layer is not particularly limited, and a conventionally known one can be used. For example, a conventional photosensitive layer that is exposed in combination with a lith film, a thermal type thermosensitive layer that can directly form an image using a laser, an unprocessed type image recording layer that does not require development processing after laser exposure, and a printing press after laser exposure. Examples thereof include an image recording layer that can be developed. The image recording layer may be a negative type or a positive type.

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.
1. Preparation of Al molten metal The components of Fe, Si, and Cu in the amounts shown in Table 1 are contained, and the remainder is prepared as Al molten metal composed of Al and inevitable impurities, and Ti is shown in Table 1. Al—Ti (5% by mass) -B (1% by mass) alloy wire was added so that the amount was 1 to prepare Al melts 1 to 9. The molten Al 2 was obtained without adding Ti.

2. Production of lithographic printing plate support (Part 1)
(Examples 1-31 and Comparative Examples 1-16)
As shown in Table 2, after cleaning the Al molten metal obtained above, the following steps are used to filter, continuous casting, cold rolling, intermediate annealing, finishing A cold rolling step, a surface roughening treatment step and an anodizing treatment step were successively carried out to obtain a lithographic printing plate support.

(1) Filtration process Al molten metal was filtered using the filter tank. A ceramic filter was used as the filter of the filter tank. In Comparative Examples 4, 8, 12 and 16, no filtration step was performed.

(2) Continuous casting process An aluminum alloy plate was continuously cast using the apparatus shown in FIG. Specifically, first, the molten aluminum is passed from the melting furnace through a filter tank (not shown) except for Comparative Examples 4, 8, 12 and 16, and further, the flow having the stirring means shown in FIG. It supplied to the molten metal supply nozzle via the path (Comparative Examples 4, 8, 12 and 16 have no stirring means) (supply process). Next, the molten aluminum was supplied between the pair of cooling rollers via the molten metal supply nozzle, and rolled while solidifying the molten aluminum with the pair of cooling rollers to form an aluminum alloy plate (casting process).
The stirring means was provided in the hot water pool (concave portion) immediately before the molten metal supply nozzle. Stirring was performed by rotating a rotary carbon rotor (diameter 50 mm) at 150 rpm while supplying Ar gas at a rate of 3 L / min through a hole penetrating the rotor shaft center.

As the molten metal supply nozzle, among the constituent members, an upper plate member that contacts the Al molten metal from the upper surface and a lower plate member that contacts the Al molten metal from the lower surface are respectively movable in the vertical direction, and the upper plate member and the lower plate A melt supply nozzle having a pressurization structure or a nozzle without such a pressurization structure was used, in which each member was pressed by the pressure of the Al melt and pressed against the surface of the adjacent cooling roller.
The positional relationship between the outer edge of the molten metal supply nozzle and the cooling roller was as shown in Table 2. In the table, A is that the outer edge of the mouth of the molten metal supply nozzle is in contact with the cooling roller only at its tip, and C is that the outer edge of the mouth of the molten metal supply nozzle is in contact with the cooling roller at its tip and other parts. Represents that
The release agent used for the median and mode diameter aggregates shown in Table 2 was applied to the inner surface of the molten metal supply nozzle in contact with the molten Al. The aggregate having a median diameter of 15 μm and a mode diameter of 8 μm was boron nitride (BN), and the aggregate having a median diameter of 5 μm and a mode diameter of 3 μm was zinc oxide (ZnO).
A release agent containing carbon graphite was intermittently spray-coated on the surface of the cooling roller, and the thickness of the applied release agent was made uniform with a wiper except for Comparative Examples 4, 8, 12 and 16. .

(3) Cold rolling process The aluminum alloy plate obtained in the continuous casting process was cold rolled to a thickness of 2 mm.

(4) Intermediate annealing process Intermediate annealing was performed by heating the aluminum alloy plate after the cold rolling process at the temperature shown in Table 2 for 10 hours. Thereby, the solid solution amount of each element of Fe, Si, and Cu was controlled.

(5) Finish cold rolling process The aluminum alloy plate after the intermediate annealing process was made into a thickness of 0.3 mm by finish cold rolling.
The amount of solid solution of each element of Fe, Si and Cu in the aluminum alloy sheet after the finish cold rolling step was as shown in Table 2.

(6) Roughening treatment step As shown in Table 2, any of the roughening treatments 1 to 4 described later was applied to the aluminum alloy plate after the finish cold rolling step.

(I) Surface roughening treatment 1
The roughening treatment 1 was performed by continuously performing the following treatments (a) to (i).

(A) Mechanical roughening treatment A roller rotating while supplying a suspension (specific gravity 1.12) of an abrasive (pumiston, average particle size 35 μm) and water as a polishing slurry to the surface of the aluminum alloy plate The surface was mechanically roughened with a nylon brush. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.48 mm. The nylon brush was planted so as to be dense by making holes in a stainless steel tube having a diameter of 300 mm (the brush hair density was 450 / cm ² ). Three rotating brushes were used. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkali etching treatment The aluminum alloy plate was subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 25% by mass, an aluminum ion concentration of 7% by mass, and a temperature of 70 ° C., thereby dissolving 7 g / m ^{2 of the} aluminum plate. Then, water washing by spraying was performed.

(C) Desmut treatment Desmut treatment by spraying was performed for 4 seconds with a 25% by weight aqueous solution of sulfuric acid having a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was continuously performed using an AC voltage of 60.0 Hz. The electrolytic solution at this time was a 1% by mass aqueous nitric acid solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 35 ° C. An electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode, using a trapezoidal rectangular wave alternating current with a time TP of 0.8 msec until the current value reached a peak and a duty ratio of 1: 1. Ferrite was used for the auxiliary anode.
The current density was 25A / dm ² at the peak current, the quantity of electricity of the aluminum plate was 180C / dm ² as the total quantity of electricity when the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode.
Then, water washing by spraying was performed.

(E) Alkali etching treatment The aluminum alloy plate was subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 25% by mass, an aluminum ion concentration of 7% by mass, and a temperature of 70 ° C., thereby dissolving 3 g / m ^{2 of the} aluminum plate. Then, water washing by spraying was performed.

(F) Desmut treatment Desmut treatment by spraying was performed for 10 seconds with a 25% by weight aqueous solution of sulfuric acid at a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an AC voltage of 60.0 Hz. The electrolytic solution at this time was a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions), and a liquid temperature of 50 ° C. An electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode, using a trapezoidal rectangular wave alternating current with a time TP of 0.8 msec until the current value reached a peak and a duty ratio of 1: 1. Ferrite was used for the auxiliary anode.
The current density was 25A / dm ² at the peak current, the quantity of electricity of the aluminum plate was 63C / dm ² as the total quantity of electricity when the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode.
Then, water washing by spraying was performed.

(H) Alkaline etching treatment An aluminum alloy plate is subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 5 mass%, an aluminum ion concentration of 0.5 mass%, and a temperature of 35 ° C., and the aluminum plate is dissolved by 0.2 g / m ^2. did. Then, water washing by spraying was performed.

(I) Desmut treatment A desmut treatment by spraying was performed for 3 seconds with a 25% by weight aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), and then washing with water by spraying was performed.

(II) Surface roughening treatment 2
In the surface roughening treatment 2, the above steps (a) and (f) to (h) are not performed, the amount of dissolved aluminum is set to 5 g / m ² in the above step (b), and the amount of electricity in the above (d) is determined by the aluminum plate being an anode. The total amount of electricity at the time is 255 C / dm ² , the temperature of the aqueous solution is 30 ° C. in the above (e), the aluminum dissolution amount is 0.3 g / m ² , and the concentration of the aqueous solution is 15 mass in the above (i). %, Except that the temperature was 30 ° C.

(III) Surface roughening treatment 3
The surface roughening treatment 3 was performed by the same method as the surface roughening treatment 1 except that the steps (f) to (h) were not performed.

(IV) Roughening treatment 4
The surface roughening treatment 4 uses a 1 mass% hydrochloric acid aqueous solution (containing 0.5 mass% of aluminum ions), a liquid temperature of 35 ° C. in place of the nitric acid aqueous solution in the above (d), and the amount of electricity is aluminum. The same method as in the surface roughening treatment 2 was performed except that the total amount of electricity when the plate was an anode was 450 C / dm ² .

(7) Anodizing treatment step The aluminum alloy plate after the roughening treatment step was anodized using an anodizing apparatus to obtain a support for a lithographic printing plate.
As the electrolytic solution, an aqueous solution having a sulfuric acid concentration of 15% by mass (including 0.5% by mass of aluminum ions) and a temperature of 35 ° C. was used. Then, water washing by spraying was performed. The final oxide film amount was 2.7 g / m ² .

3. Evaluation of lithographic printing plate support About the lithographic printing plate support obtained above, surface treatment unevenness, uniformity of electrochemical roughening treatment, and resistance to lithographic printing plate are as follows. The printability was evaluated.
(1) Surface treatment unevenness Surface treatment unevenness is chatter marks (horizontal stripe-like treatment unevenness generated perpendicular to the traveling direction of the aluminum alloy plate), black stripes (black stripe-like surface treatment unevenness), crystal stripes (long gray ( 100 mm or more) streaky surface treatment unevenness), streaks (short gray (100 mm or less) streaky surface treatment unevenness), and cosmetics (thin white scratch-like streaks), and each was visually evaluated for sensory evaluation. For each unevenness, the evaluation was made in five stages: ○, ○ Δ, Δ, Δx, and x, from those with less unevenness to those with large unevenness. Δ is the practical limit.
The results are shown in Table 3.

(2) Uniformity of electrochemical roughening treatment The surface of the lithographic printing plate support was observed at a magnification of 2000 times using SEM, and sensory evaluation was performed on the uniformity of the electrochemical roughening treatment. Evaluation was made into five steps, from the higher uniformity to the less uniform, ○, ○ △, Δ, Δx, and x.
The results are shown in Table 3.

(3) Printing durability when used as a lithographic printing plate Each lithographic printing plate support obtained above was provided with a thermal positive type image recording layer as follows to obtain a lithographic printing plate precursor. Before providing the image recording layer, an undercoat layer was provided as described later.

An undercoat solution having the following composition was applied onto a lithographic printing plate support 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>
・ The following polymer compound 0.3g
・ Methanol 100g
・ Water 1g

Furthermore, a heat-sensitive layer coating solution having the following composition was prepared, and the coating amount after drying the heat-sensitive layer coating solution (heat-sensitive layer coating amount) on a lithographic printing plate support provided with an undercoat layer was 1.8 g / m. ² was applied and dried to form a heat sensitive layer (thermal positive type image recording layer) to obtain a lithographic printing plate precursor.

<Thermosensitive layer coating solution composition>
Novolak resin (m-cresol / p-cresol = 60/40, weight average molecular weight 7,000, containing 0.5% by mass of unreacted cresol) 0.90 g
・ Ethyl methacrylate / isobutyl methacrylate / methacrylic acid copolymer (molar ratio 35/35/30) 0.10 g
-Cyanine dye A 0.1 g represented by the following structural formula
・ Tetrahydrophthalic anhydride 0.05g
・ 0.002 g of p-toluenesulfonic acid
-Ethyl violet counter ion with 6-hydroxy-β-naphthalenesulfonic acid 0.02 g
・ Fluorosurfactant (Megafac F-780F, manufactured by Dainippon Ink and Chemicals, solid content: 30% by mass) 0.0045 g (solid content conversion)
・ Fluorosurfactant (Megafac F-781F, manufactured by Dainippon Ink & Chemicals, Inc., solid content: 100% by mass) 0.035 g
・ Methyl ethyl ketone 12g

Next, the obtained lithographic printing plate precursor was imaged using a TrendSetter manufactured by Creo at a drum rotation speed of 150 rpm and a beam intensity of 10 W.
Thereafter, using a PS processor 940H manufactured by Fuji Photo Film Co., Ltd., charged with an alkali developer having the following composition, the solution temperature was maintained at 30 ° C. and development was performed for 20 seconds to obtain a lithographic printing plate.

<Alkali developer composition>
・ D-Sorbit 2.5% by mass
-Sodium hydroxide 0.85 mass%
・ Polyethylene glycol lauryl ether (weight average molecular weight 1,000)
0.5% by mass
・ Water 96.15% by mass

The resulting lithographic printing plate was printed on a Lithrone printing machine manufactured by Komori Corporation using DIC-GEOS (N) black ink manufactured by Dainippon Ink & Chemicals, Inc. The printing durability was evaluated based on the number of printed sheets when visually recognized.
The results are shown in Table 3. The meanings of the symbols in Table 3 are as follows.
◎: 70,000 or more ○: 60,000 or more and less than 70,000 ○ ○: 50,000 or more and less than 60,000 △: 40,000 or more and less than 50,000 △: 30,000 More than 40,000 sheets ×: less than 30,000 sheets

As is apparent from Tables 1 to 3, the lithographic printing plate support produced by the method corresponding to any of the first to fourth aspects of the lithographic printing plate support production method of the present invention. (Examples 1-31) have no surface treatment unevenness on the surface, are excellent in the uniformity of the electrochemical surface-roughening treatment, and are excellent in printing durability when used as a lithographic printing plate. It was.
On the other hand, when the amount of each element of Fe, Si and Cu in the molten Al is too large (Comparative Examples 3, 7, 11 and 15), the Fe, Si and Cu of the aluminum alloy sheet after the finish cold rolling step When the amount of the solid solution of each element is too small (Comparative Examples 1, 2, 4 to 6, 8 to 10, 12 to 14 and 16), and in the continuous casting process of the aluminum alloy plate, it causes surface treatment unevenness. When the method of suppressing various nonuniformities was not used (Comparative Examples 4, 8, 12 and 16), various surface treatment unevenness, uniformity of electrochemical surface roughening treatment, and lithographic printing plate It was inferior to one or more printing durability.

4). Production of lithographic printing plate support (Part 2)
(Examples 32 and 33 and Comparative Examples 17-20)
As shown in Table 4, after performing the cleaning process on the Al molten metal obtained above, the filtration process, the continuous casting process, the cold rolling process, the intermediate annealing process, and the finishing by the methods shown below A cold rolling step, a surface roughening treatment step and an anodizing treatment step were successively carried out to obtain a lithographic printing plate support.

(1) Filtration process Al molten metal was filtered using the filter tank. A ceramic filter was used as the filter of the filter tank. In Comparative Examples 18 and 20, the filtration step was not performed.

(2) Continuous casting process An aluminum alloy plate was continuously cast using the apparatus shown in FIG. Immediately before the molten metal in the holding furnace ceased, casting was continued without interruption on the way by additionally supplying molten aluminum from a melting furnace not shown. Specifically, first, the molten Al is passed from the melting furnace through a filter tank (not shown) except for Comparative Examples 18 and 20, and further, a flow path having a stirring means shown in FIG. 17, 18, 19, and 20 were supplied to the molten metal supply nozzle via a stirring means (supply step). Next, the molten aluminum was supplied between the pair of cooling rollers via the molten metal supply nozzle, and rolled while solidifying the molten aluminum with the pair of cooling rollers to form an aluminum alloy plate (casting process). Here, a sample obtained by casting about 100 tons (90 to 110 tons) from the start of casting was used.
The stirring means was provided in the hot water pool (concave portion) immediately before the molten metal supply nozzle. Stirring was performed by rotating a rotary carbon rotor (diameter 50 mm) at 150 rpm while supplying Ar gas at a rate of 3 L / min through a hole penetrating the rotor shaft center.

As the molten metal supply nozzle, the nozzle without the pressure structure described above was used.
The positional relationship between the outer edge of the molten metal supply nozzle and the cooling roller was set to a clearance of 0.5 mm.
The mold release agent was not applied to the inner surface of the molten metal supply nozzle in contact with the molten Al.
No release agent containing carbon graphite was applied to the surface of the cooling roller.

(3) Cold rolling process The aluminum alloy plate obtained in the continuous casting process was cold rolled to a thickness of 2 mm.

(4) Intermediate annealing process The intermediate annealing was performed by heating the aluminum alloy plate after a cold rolling process at 550 degreeC for 10 hours. Thereby, the solid solution amount of each element of Fe, Si, and Cu was controlled.

(5) Finish cold rolling process The aluminum alloy plate after the intermediate annealing process was made into a thickness of 0.3 mm by finish cold rolling.
The amount of solid solution of each element of Fe, Si and Cu in the aluminum alloy sheet after the finish cold rolling process was as shown in Table 4.

(6) Roughening treatment step The above-described roughening treatment 3 was applied to the aluminum alloy plate after the finish cold rolling step.

(7) Anodizing treatment step The aluminum alloy plate after the roughening treatment step was anodized using an anodizing apparatus to obtain a support for a lithographic printing plate.
As the electrolytic solution, an aqueous solution having a sulfuric acid concentration of 15% by mass (including 0.5% by mass of aluminum ions) and a temperature of 35 ° C. was used. Then, water washing by spraying was performed. The final oxide film amount was 2.7 g / m ² .

5. Evaluation of lithographic printing plate support (Part 2)
About the lithographic printing plate support obtained above, the black stripes of the surface treatment unevenness were visually evaluated. The evaluation was made into four stages of ○, Δ ×, ×, and XX from those with few black stripes to those with many. ○ is practically no problem.
The results are shown in Table 4.

As is apparent from Table 4, the black plank does not occur in the planographic printing plate support (Examples 32 and 33) produced in the first aspect of the planographic printing plate support production method of the present invention. It was.
In contrast, black streaks occurred when the filtration step was not performed (Comparative Examples 18 and 20) and when the filtration step was not performed (Comparative Examples 17 and 19).
As a result of analyzing the generated black streak with EPMA (electron beam microanalyzer, 8800M, manufactured by JEOL Ltd.), both Ti and B compounds were detected. In the case of using the Al molten metal 3 (Comparative Examples 17 and 18), when an alloy wire of Al—Ti (5 mass%)-B (1 mass%) is added for crystal refinement, it is coarse. It is considered that the TiB compound (presumed to be TiB ₂ ) segregated and became black stripes. In addition, when the molten Al 2 was used (Comparative Examples 19 and 20), black streaks were generated despite the fact that Ti was not supplied. It is presumed that TiB ₂ particles that settled at the bottom of the flow channel were mixed during casting.

6). Production of lithographic printing plate support (Part 3)
(Examples 34 and 35 and Comparative Examples 21 and 22)
As shown in Table 5, after performing the cleaning treatment on the Al molten metal obtained above, in the following manner, continuous casting process, cold rolling process, intermediate annealing process, finish cold rolling The lithographic printing plate support was obtained by continuously performing the steps, the surface roughening treatment step and the anodizing treatment step. In addition, the filtration process was not performed before the continuous casting process.

(1) Continuous casting process An aluminum alloy plate was continuously cast using the apparatus shown in FIG. Specifically, first, Al molten metal was supplied from the melting furnace to the molten metal supply nozzle (supply process). At this time, stirring was not performed. Next, the molten aluminum was supplied between the pair of cooling rollers via the molten metal supply nozzle, and rolled while solidifying the molten aluminum with the pair of cooling rollers to form an aluminum alloy plate (casting process).

As shown in Table 5, as the molten metal supply nozzle, the upper plate member that contacts the Al molten metal from the upper surface and the lower plate member that contacts the Al molten metal from the lower surface are movable in the vertical direction. The upper plate member and the lower plate member are each pressurized by the pressure of the Al molten metal and pressed against the surface of the adjacent cooling roller, and there is no molten metal supply nozzle having a pressure structure or such a pressure structure. A nozzle was used.
The positional relationship between the outer edge of the molten metal supply nozzle and the cooling roller was set to a clearance of 0.5 mm.
The mold release agent was not applied to the inner surface of the molten metal supply nozzle in contact with the molten Al.
No release agent containing carbon graphite was applied to the surface of the cooling roller.

(2) Cold rolling process The aluminum alloy plate obtained in the continuous casting process was cold rolled to a thickness of 2 mm.

(3) Intermediate annealing process Intermediate annealing was performed by heating the aluminum alloy plate after the cold rolling process at 550 ° C for 10 hours. Thereby, the solid solution amount of each element of Fe, Si, and Cu was controlled.

(4) Finish cold rolling process The aluminum alloy plate after the intermediate annealing process was made into a thickness of 0.3 mm by finish cold rolling.
The amount of solid solution of each element of Fe, Si and Cu in the aluminum alloy sheet after the finish cold rolling process was as shown in Table 5.

(5) Roughening treatment step The aforementioned roughening treatment 3 was applied to the aluminum alloy plate after the finish cold rolling step.

(6) Anodizing treatment step The aluminum alloy plate after the roughening treatment step was anodized using an anodizing apparatus to obtain a support for a lithographic printing plate.
As the electrolytic solution, an aqueous solution having a sulfuric acid concentration of 15% by mass (including 0.5% by mass of aluminum ions) and a temperature of 35 ° C. was used. Then, water washing by spraying was performed. The final oxide film amount was 2.7 g / m ² .

7). Evaluation of lithographic printing plate support (Part 3)
The lithographic printing plate support obtained above was subjected to visual sensory evaluation of the ripple mark of uneven surface treatment. In the evaluation, “◯” indicates a small number of ripple marks and “×” indicates a large number of ripple marks. ○ is practically no problem.
The results are shown in Table 5.

As is apparent from Table 5, the lithographic printing plate support (Examples 34 and 35) produced by the second aspect of the method for producing a lithographic printing plate support of the present invention has no ripple mark. It was.
On the other hand, when a melt supply nozzle without a pressurizing structure was used (Comparative Examples 21 and 22), ripple marks were generated.

8). Manufacture of lithographic printing plate support (Part 4)
(Examples 36 and 37 and Comparative Examples 23 and 24)
As shown in Table 6, after the cleaning treatment was performed on the Al molten metal obtained above, the continuous casting process, the cold rolling process, the intermediate annealing process, and the finish cold rolling were performed in the following manner. The lithographic printing plate support was obtained by continuously performing the steps, the surface roughening treatment step and the anodizing treatment step. In addition, the filtration process was not performed before the continuous casting process.

(1) Continuous casting process An aluminum alloy plate was continuously cast using the apparatus shown in FIG. Specifically, first, Al molten metal was supplied from the melting furnace to the molten metal supply nozzle (supply process). At this time, stirring was not performed. Next, the molten aluminum was supplied between the pair of cooling rollers via the molten metal supply nozzle, and rolled while solidifying the molten aluminum with the pair of cooling rollers to form an aluminum alloy plate (casting process).

As the molten metal supply nozzle, the nozzle without the pressure structure described above was used.
The positional relationship between the outer edge of the molten metal supply nozzle and the cooling roller was set to a clearance of 0.5 mm.
The mold release agent used for the median diameter and mode diameter aggregates shown in Table 6 was applied to the inner surface of the molten metal supply nozzle in contact with the molten Al. The aggregate having a median diameter of 15 μm and a mode diameter of 8 μm was boron nitride (BN), and the aggregate having a median diameter of 5 μm and a mode diameter of 3 μm was zinc oxide (ZnO).
No release agent containing carbon graphite was applied to the surface of the cooling roller.

(2) Cold rolling process The aluminum alloy plate obtained in the continuous casting process was cold rolled to a thickness of 2 mm.

(3) Intermediate annealing process Intermediate annealing was performed by heating the aluminum alloy plate after the cold rolling process at 550 ° C for 10 hours. Thereby, the solid solution amount of each element of Fe, Si, and Cu was controlled.

(4) Finish cold rolling process The aluminum alloy plate after the intermediate annealing process was made into a thickness of 0.3 mm by finish cold rolling.
Table 6 shows the solid solution amounts of the Fe, Si and Cu elements in the aluminum alloy sheet after the finish cold rolling process.

(5) Roughening treatment step The aforementioned roughening treatment 3 was applied to the aluminum alloy plate after the finish cold rolling step.

(6) Anodizing treatment step The aluminum alloy plate after the roughening treatment step was anodized using an anodizing apparatus to obtain a support for a lithographic printing plate.
As the electrolytic solution, an aqueous solution having a sulfuric acid concentration of 15% by mass (including 0.5% by mass of aluminum ions) and a temperature of 35 ° C. was used. Then, water washing by spraying was performed. The final oxide film amount was 2.7 g / m ² .

9. Evaluation of lithographic printing plate support (Part 4)
The lithographic printing plate support obtained above was subjected to visual sensory evaluation of crystal stripes of surface treatment unevenness. The evaluation was made in three stages: ○, Δ ×, and X, from the smallest crystal streak to the larger one. ○ is practically no problem.
The results are shown in Table 6.

As is apparent from Table 6, the lithographic printing plate support (Examples 36 and 37) produced by the third aspect of the lithographic printing plate support production method of the present invention does not generate crystal streaks. It was.
On the other hand, when the aggregate of the release agent applied to the inner surface of the molten metal supply nozzle in contact with the Al molten metal had a median diameter of 5 μm and a mode diameter of 3 μm (Comparative Examples 23 and 24), crystal streaks occurred.

10. Manufacture of lithographic printing plate support (Part 5)
(Examples 38 and 39 and Comparative Examples 25 to 28)
As shown in Table 7, after the cleaning treatment was performed on the Al molten metal obtained above, the continuous casting process, the cold rolling process, the intermediate annealing process, and the finish cold rolling were performed in the following manner. The lithographic printing plate support was obtained by continuously performing the steps, the surface roughening treatment step and the anodizing treatment step. In addition, the filtration process was not performed before the continuous casting process.

(1) Continuous casting process An aluminum alloy plate was continuously cast using the apparatus shown in FIG. Specifically, first, Al molten metal was supplied from the melting furnace to the molten metal supply nozzle (supply process). At this time, stirring was not performed. Next, the molten aluminum was supplied between the pair of cooling rollers via the molten metal supply nozzle, and rolled while solidifying the molten aluminum with the pair of cooling rollers to form an aluminum alloy plate (casting process).

As the molten metal supply nozzle, the nozzle without the pressure structure described above was used.
The positional relationship between the outer edge of the molten metal supply nozzle and the cooling roller was as shown in Table 7. In the table, A is that the outer edge of the mouth of the melt supply nozzle is in contact with the cooling roller only at the tip, B is that the outer edge of the mouth of the melt supply nozzle is not in contact with the cooling roller, and C is the melt supply nozzle. This means that the outer edge of the mouth is in contact with the cooling roller at the tip and other parts.
The mold release agent was not applied to the inner surface of the molten metal supply nozzle in contact with the molten Al.
On the surface of the cooling roller, a release agent containing carbon graphite was intermittently spray-applied. Except for Comparative Examples 26 to 28, the thickness of the applied release agent was made uniform with a wiper.

(2) Cold rolling process The aluminum alloy plate obtained in the continuous casting process was cold rolled to a thickness of 2 mm.

(3) Intermediate annealing process Intermediate annealing was performed by heating the aluminum alloy plate after the cold rolling process at 550 ° C for 10 hours. Thereby, the solid solution amount of each element of Fe, Si, and Cu was controlled.

(4) Finish cold rolling process The aluminum alloy plate after the intermediate annealing process was made into a thickness of 0.3 mm by finish cold rolling.
The amount of solid solution of each element of Fe, Si and Cu in the aluminum alloy sheet after the finish cold rolling process was as shown in Table 7.

(5) Roughening treatment step The aforementioned roughening treatment 3 was applied to the aluminum alloy plate after the finish cold rolling step.

(6) Anodizing treatment step The aluminum alloy plate after the roughening treatment step was anodized using an anodizing apparatus to obtain a support for a lithographic printing plate.
As the electrolytic solution, an aqueous solution having a sulfuric acid concentration of 15% by mass (including 0.5% by mass of aluminum ions) and a temperature of 35 ° C. was used. Then, water washing by spraying was performed. The final oxide film amount was 2.7 g / m ² .

11. Evaluation of lithographic printing plate support (Part 5)
The lithographic printing plate support obtained above was subjected to visual sensory evaluation for streaks and cosmesji of surface treatment unevenness. In the evaluation, for each non-uniformity, the case where there was little non-uniformity was rated as ◯, and the case where there was a large amount was x. ○ is practically no problem.
The results are shown in Table 7.

As is apparent from Table 7, the lithographic printing plate support (Examples 38 and 39) produced by the fourth aspect of the lithographic printing plate support production method of the present invention produced streaks and jerseys. There wasn't.
On the other hand, when the outer edge of the mouth of the molten metal supply nozzle is in contact with the cooling roller at the tip and other portions (Comparative Examples 25 and 28), a rust is generated and the release applied to the cooling roller. When the thickness of the agent was not uniformized with a wiper (Comparative Examples 26 to 28), streaks occurred.

It is a schematic diagram which shows an example of a structure from a melting furnace to a casting apparatus. It is a schematic diagram which shows the example of the recessed part provided with the stirring means. It is a schematic diagram which shows another example of the recessed part provided with the stirring means. It is a schematic diagram which shows the example of the positional relationship of a cooling roller, a molten metal supply nozzle, an aluminum alloy plate, Al molten metal, and a molten metal meniscus part. It is a schematic diagram which shows the suitable example of the shape of a molten metal supply nozzle, and its positional relationship with the cooling roller. It is a schematic diagram which shows another example of the molten metal supply nozzle whose front-end | tip is a movable structure. It is a schematic diagram which shows the example of the cold rolling mill used for cold rolling. It is a schematic diagram which shows the example of a correction apparatus.

Explanation of symbols

3 Melt meniscus portion 4a, 4b Nozzle plate 10 Casting device 12 Melting furnace 14 Flow path 16, 16B Molten metal supply nozzle 18 Cooling roller 22 Al molten metal 30 Recess 36 Aluminum alloy plate 40 Upper plate member 42 Lower plate member 43 Gas discharge portion 45 Rotor 46 Air bubbles 50 Cold rolling mill 52, 82 Sending coil 54, 84 Winding coil 56 Rolling roller 58 Support roller 70 Straightening device 80 Leveler part 86 Work roll 88 Slitter 92 Bar member C Clearance D Cooling roller diameter T Tip t Thickness of aluminum alloy plate

Claims (6)

A continuous casting step of supplying an aluminum alloy molten metal between a pair of cooling rollers via a molten metal supply nozzle, and forming an aluminum alloy plate by rolling while solidifying the molten aluminum alloy by the pair of cooling rollers;
A cold rolling step for reducing the thickness of the aluminum alloy plate obtained in the continuous casting step;
An intermediate annealing step of performing a heat treatment on the aluminum alloy plate in the cold rolling step;
A finish cold rolling step for reducing the thickness of the aluminum alloy sheet after the intermediate annealing;
The surface of the aluminum alloy plate after the finish cold rolling step is subjected to a roughening treatment including at least an alkali etching treatment and a subsequent electrochemical roughening treatment to obtain a lithographic printing plate support. A roughening treatment step,
The angle of the lower outer surface of the tip of the molten metal supply nozzle is an acute angle with respect to the discharge direction of the molten aluminum alloy, and among the members constituting the molten metal supply nozzle, the aluminum alloy An upper plate member that is in contact with the molten metal from the upper surface and a lower plate member that is in contact with the molten aluminum alloy from the lower surface are respectively movable in the vertical direction, and the upper plate member and the lower plate member are each of the aluminum alloy. A method for producing a support for a lithographic printing plate satisfying one or both of being pressed by the pressure of a molten metal and being pressed against the surface of the adjacent cooling roller,
The aluminum alloy melt contains 95% by mass or more of Al, 30 to 5000 ppm Fe, 300 to 2000 ppm Si, and 1 to 500 ppm Cu,
The finish cold said aluminum alloy plate after rolling, a solid solution amount of Fe 20ppm or more, a solid solution amount of Si is 20ppm or more state, and are dissolved amount Cu is more than 70 wt% of the total amount of Cu,
In the continuous casting process, the pair of cooling rollers is coated with a release agent containing carbon graphite on the surface thereof, and then a wiper is brought into contact with the surface of the cooling roller at a constant pressure to apply the release agent. A method for producing a lithographic printing plate support , wherein the thickness of the mold is made uniform, and the outer edge of the mouth of the molten metal supply nozzle does not contact the cooling roller or contacts only at the tip thereof . A continuous casting step of supplying an aluminum alloy molten metal between a pair of cooling rollers via a molten metal supply nozzle, and forming an aluminum alloy plate by rolling while solidifying the molten aluminum alloy by the pair of cooling rollers;
A cold rolling step for reducing the thickness of the aluminum alloy plate obtained in the continuous casting step;
An intermediate annealing step of performing a heat treatment on the aluminum alloy plate in the cold rolling step;
A finish cold rolling step for reducing the thickness of the aluminum alloy sheet after the intermediate annealing;
The surface of the aluminum alloy plate after the finish cold rolling step is subjected to a roughening treatment including at least an alkali etching treatment and a subsequent electrochemical roughening treatment to obtain a lithographic printing plate support. A roughening treatment step,
A release agent containing aggregate particles having a particle size distribution with a median diameter of 5 to 20 μm and a mode diameter of 4 to 12 μm is applied in advance to the inner surface of the molten metal supply nozzle in contact with the molten aluminum alloy. A method for producing a lithographic printing plate support,
The aluminum alloy melt contains 95% by mass or more of Al, 30 to 5000 ppm Fe, 300 to 2000 ppm Si, and 1 to 500 ppm Cu,
The finish cold said aluminum alloy plate after rolling, a solid solution amount of Fe 20ppm or more, a solid solution amount of Si is 20ppm or more state, and are dissolved amount Cu is more than 70 wt% of the total amount of Cu,
In the continuous casting process, the pair of cooling rollers is coated with a release agent containing carbon graphite on the surface thereof, and then a wiper is brought into contact with the surface of the cooling roller at a constant pressure to apply the release agent. A method for producing a lithographic printing plate support , wherein the thickness of the mold is made uniform, and the outer edge of the mouth of the molten metal supply nozzle does not contact the cooling roller or contacts only at the tip thereof . A continuous casting step of supplying an aluminum alloy molten metal between a pair of cooling rollers via a molten metal supply nozzle, and forming an aluminum alloy plate by rolling while solidifying the molten aluminum alloy by the pair of cooling rollers;
A cold rolling step for reducing the thickness of the aluminum alloy plate obtained in the continuous casting step;
An intermediate annealing step of performing a heat treatment on the aluminum alloy plate in the cold rolling step;
A finish cold rolling step for reducing the thickness of the aluminum alloy sheet after the intermediate annealing;
The surface of the aluminum alloy plate after the finish cold rolling step is subjected to a roughening treatment including at least an alkali etching treatment and a subsequent electrochemical roughening treatment to obtain a lithographic printing plate support. A roughening treatment step,
In the continuous casting process, the pair of cooling rollers is coated with a release agent containing carbon graphite on the surface thereof, and then a wiper is brought into contact with the surface of the cooling roller at a constant pressure to apply the release agent. A method for producing a support for a lithographic printing plate, wherein the thickness of the mold is made uniform, and the outer edge of the mouth of the molten metal supply nozzle does not contact the cooling roller or contacts only at the tip thereof,
The aluminum alloy melt contains 95% by mass or more of Al, 30 to 5000 ppm Fe, 300 to 2000 ppm Si, and 1 to 500 ppm Cu,
The support for a lithographic printing plate, wherein the aluminum alloy sheet after the finish cold rolling has a solid solution Fe amount of 20 ppm or more, a solid solution Si amount of 20 ppm or more, and a solid solution Cu amount of 70% by mass or more of the total Cu amount. Body manufacturing method. Wherein the molten aluminum alloy, the mother alloy containing TiB ₂ is added, the process for producing a lithographic printing plate support according to any one of claims 1 to 3. 5. A filtration step of filtering the aluminum alloy molten metal using a filter tank before the continuous casting step is provided, and the filter tank is disposed downstream from a position where the mother alloy containing TiB ₂ is added. The manufacturing method of the support body for lithographic printing plates as described in 1 above . The molten aluminum alloy contains 250 to 350 ppm of Cu,
The surface roughening treatment step, the surface of the aluminum alloy plate after the finish cold rolling step, mechanical surface roughening treatment, alkali etching treatment, desmut treatment, electrochemical surface roughening treatment, alkali etching treatment, The method for producing a lithographic printing plate support according to any one of claims 1 to 5, which is a roughening treatment step in which desmutting treatment, electrochemical roughening treatment, alkali etching treatment, and desmutting treatment are performed in this order. .

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