JP2001271133A - Substrate for planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum alloy substrate for planographic printing plate excellent in printing durability, ink stain resistance and surface quality. SOLUTION: This substrate is obtained by subjecting an aluminum alloy sheet containing, by mass, 0.2 to 0.5% Fe, 0.04 to 0.20% Si, 0.005 to 0.040% Cu, 0.010 to 0.040% Ti, 0.001 to 0.020% Mg and 0.005 to 0.2% Ni, and Al as rest with inevitable impurities to a surface roughening treatment including an electrochemical surface roughening treatment. In the substrate, the relation among Ni content [Ni], Cu content [Cu] and average surface roughness [Ra] (μm) satisfies the following inequality (1): [Ni]/10+[Ra]/100<=[Cu] (1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate support, and more particularly to a lithographic printing plate support excellent in printing durability, stain resistance and surface quality.

[0002]

2. Description of the Related Art A photosensitive lithographic printing plate having an aluminum plate as a support is widely used for offset printing. The lithographic printing plate precursor is generally manufactured by roughening the surface of an aluminum plate, further performing anodizing treatment, applying a photosensitive liquid, and drying to form a photosensitive layer. The lithographic printing plate precursor is exposed to an image and then developed with a developer, and the exposed portion is removed in the positive type lithographic printing plate precursor, and the non-exposed portion is removed in the negative type lithographic printing plate precursor. The plate is made into a lithographic printing plate. afterwards,
The lithographic printing plate has its surface coated with ink and is subjected to printing. In this way, in the lithographic printing plate precursor, the physical properties of the photosensitive layer are changed by exposure,
We are making plates.

Conventionally, as a method for roughening an aluminum alloy plate, a mechanical roughening method such as ball grain or brush grain, and an electrochemical roughing method using electrolytic solution mainly containing hydrochloric acid, nitric acid or the like are used. A surface roughening (hereinafter also referred to as “electrolytic surface roughening”) method, a chemical surface roughening method of etching with an acid solution, and the like are known. In recent years, the rough surface obtained by the electrolytic surface roughening method has uniform pits and excellent printing performance. Therefore, it is possible to roughen the surface by combining the electrolytic surface roughening method and other surface roughening methods. It has become mainstream.

[0004] For example, a “waviness-like” or “wrinkle-like” rough surface having an average surface roughness Ra of about 0.30 to 1.0 μm is formed on an aluminum alloy plate by electrolytic surface roughening treatment, and the diameter of the surface is further increased to 0. "Honeycomb-like" and "crater-like" pits having a depth of about 2 to 20 m and a depth of about 0.05 to 1 m are formed. In the case where the “undulation” or “wrinkle” rough surface due to the electrolytic surface roughening treatment is not uniform, it is preferable to combine mechanical or chemical surface roughening treatment because the uniformity increases.

[0005] The problem in the case where the surface roughening by the surface roughening process is non-uniform (the diameter and depth of the pits are non-uniform) is described by a schematic diagram showing the cross-sectional structure of a conventional lithographic printing plate precursor 10 (FIGS. 1 and 2). This will be described using 2). The lithographic printing plate precursor 10 is a laminate having an aluminum alloy plate support 12 on which pits (irregularities) p are formed and a photosensitive layer 14 laminated thereon. When the depth of the pit p in the exposure direction is non-uniform (FIG. 1A), for example, when a deep pit p ′ is exposed, halation (non-uniform scattering of light) occurs (FIG. b)), the unexposed portion also changes its physical properties similarly to the exposed portion (FIG. 1 (c)). As a result, "fogging" may occur in the printed image. Also, as shown in FIG. 2, when a wide area including the pit p and the pit p ′ is exposed, the exposure is insufficient at the bottom of the pit p ′ farther from the light source (FIG. 2B). A non-exposed portion may occur in the portion (FIG. 2C). As a result, although the portion where the photosensitive layer is removed originally becomes a non-image, it partially shows the characteristics of the image portion and is likely to be a starting point of the occurrence of stains during printing.

Although not shown in FIGS. 1 and 2, if the undulations are uneven, the adhesion between the photosensitive layer 14 and the support 12 also decreases. Along with this, the printing durability of the lithographic printing plate after plate making is reduced. In addition, the photosensitive layer 1 of a direct-drawing lithographic printing plate (lithographic printing plate for laser plate making), which has attracted attention in recent years,
No. 4 has higher sensitivity to the adhesion to the substrate than the photosensitive layer of a lithographic printing plate precursor requiring a plate making film at the time of plate making, and it is desired to improve printing durability. Also, when making a plate using a laser, exposure defects are more likely to occur,
The uniformity of the undulations is extremely important.

As described above, the unevenness of the rough surface of the lithographic printing plate, which greatly affects the printing performance such as the printing durability of the lithographic printing plate precursor, is made uniform by changing the alloy composition of the aluminum alloy plate. There are many suggestions. For example, conventionally, as an electrolytic surface roughening method, 0.05 to 1% by weight of Fe and 0.01 to 1% by weight of Si have been used.
By adding 0.05 to 0.1% by weight of Cu to the aluminum alloy support containing 0.15% by weight, generation of minute streaks is suppressed, and uniformity of the rough surface by electrolytic etching is ensured. A method has been proposed (JP-A-11-99763).

Further, Fe in the aluminum alloy support is
Is regulated to 0.05 to 1% by weight, Si to 0.015 to 0.2% by weight, Cu to 0.001% by weight or less, and elemental Si distributed in the metal structure to 0.015% by weight or more. Thus, a method has been proposed for obtaining a support having excellent roughness uniformity, fatigue strength and burning characteristics by electrolytic etching (Japanese Patent Application Laid-Open No. 11-99764).

Further, Fe in the aluminum alloy support is
0.05 to 1% by weight, 0.015 to 0.2% by weight of Si, 0.001 to 0.05% by weight of Cu, and 0.015% by weight of elemental Si distributed in the metal structure. By controlling as described above, a method has been proposed for obtaining a support having no streak and excellent in roughness uniformity, fatigue strength, and burning characteristics by electrolytic etching (Japanese Patent Laid-Open No. 11-99765).

In addition, Fe in the aluminum alloy support
0.20 to 0.6% by weight, Si 0.03 to 0.15
% Of Ti and 0.005 to 0.05% by weight or less, and a part or all of the elements form an intermetallic compound. 1000 to 8000 pieces /
By restricting to ² mm, a method of forming pits without unetched portions by electrolytic roughening treatment in a short time and uniformly forming roughened pits even when the pits are shallow are proposed. (Japanese Patent Laid-Open No. 11-115333)
No.).

Further, Fe in the aluminum alloy support is
0.20 to 0.6% by weight, Si 0.03 to 0.15
Wt%, 0.005 to 0.05 wt% Ti, and N
i is 0.005 to 0.20% by weight, and part or all of the elements form an intermetallic compound, the intermetallic compound contains Al, and further contains 20 to 30% by weight of Fe, Si 0.3-0.8% by weight, and 0.3% Ni
There has been proposed a method for uniformly forming roughened pits by regulating the content of pits to 10 to 10% by weight (Japanese Patent Application Laid-Open No. 9-279272).

In addition, Fe in the aluminum alloy support
0.20 to 0.6% by weight, Si 0.03 to 0.15
% By weight, 0.005 to 0.05% by weight of Ti, 0.005 to 0.20% by weight of Ni, and 0.005 to 0.
05% by weight, and 0.005 to 0.020% by weight of V
A method of uniformly forming a roughened pit by regulating the contents of Ti, Ga and V so as to satisfy a predetermined relational expression has been proposed (JP-A-9-27927).
No. 4).

Further, Fe in the aluminum alloy support is
Is 0.05 to 1% by weight, Si is 0.01 to 0.2% by weight, Cu is 0.001% by weight or less, and N
0.003 to 0.1% by weight of one or two of i and Cr
There has been proposed a method of obtaining a support having excellent uniformity of the rough surface by electrolytic etching by containing the same (JP-A-11-99760).

However, JP-A-11-115333, JP-A-11-99764, and JP-A-11-99
765, JP-A-9-279272, JP-A-9-279274 and JP-A-11-99760
As in the case of Japanese Patent Publication No.
When Cu is not contained, or when the content is 0.
If the amount is less than 001% by weight, deep electrolytic surface roughening pits cannot be obtained, resulting in poor printing durability and stain resistance.

Conversely, as in the case of Japanese Patent Application Laid-Open No. H11-99763, Cu is contained in the aluminum alloy support in a content of 0.1%.
When it is contained in a large amount of not less than 05% by weight, the electrolytic surface roughening cannot be carried out uniformly, and a portion of insufficient surface roughening called unetched tends to occur, and there is a disadvantage that the stain resistance is particularly poor.

Furthermore, these supports have the disadvantage that, due to the occurrence of the above-described insufficiently roughened portions, minute glossy portions are formed on the surface, and the surface quality is poor.

[0017]

SUMMARY OF THE INVENTION The present invention solves the disadvantages of the aluminum alloy support for a lithographic printing plate containing Fe, Si, Cu, Ti and Mg as essential components, which has been proposed previously, and which has not existed in the past. An object of the present invention is to provide an aluminum alloy support for a lithographic printing plate which is excellent in printing durability, stain resistance and surface quality.

[0018]

Means for Solving the Problems In the aluminum alloy support containing Fe, Si, Cu, Ti and Mg as essential components as proposed above, the present inventor further requires a specific amount of Ni as an essential component, and By adjusting the contents of Cu and Ni in a specific range according to the value of the average surface roughness Ra after the surface roughening treatment, large and deep roughened pits can be made uniform and minute gloss Since no portion remains, it was found that a lithographic printing plate support excellent in printing durability, stain resistance and surface quality was obtained, and the present invention was completed.

That is, according to the present invention, Fe is contained in the range of 0.2 to 0.1.
5% by mass, 0.04 to 0.20% by mass of Si, 0.005 to 0.040% by mass of Cu, 0.010% by mass of Ti
An aluminum alloy plate containing 0.040% by mass, 0.001 to 0.020% by mass of Mg, and 0.005 to 0.2% by mass of Ni, with the balance being Al and unavoidable impurities, A lithographic printing plate support that has been subjected to a surface roughening treatment including a surface roughening (electrolytic surface roughening) treatment, wherein the Ni content: [Ni] (% by mass) and the Cu content: [Cu]
The present invention provides a lithographic printing plate support characterized in that (mass%) and average surface roughness Ra: [Ra] (μm) satisfy the following formula (1). [Ni] / 10 + [Ra] / 100 ≦ [Cu] (1)

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The lithographic printing plate support of the present invention comprises:
Made of aluminum alloy. The essential alloy components are Al,
Fe, Si, Cu, Ti, Mg and Ni.

Fe combines with other elements in the aluminum alloy to form an Al-Fe eutectic compound. A
The l-Fe eutectic compound makes the recrystallized grains finer and forms a uniform electrochemically rough surface. However, when the Fe content is less than 0.2% by mass, a uniform rough surface cannot be obtained. In addition, uniformity of pits is reduced due to insufficient electrochemical treatment (electrolysis). On the other hand, when the content exceeds 0.5% by mass, a coarse compound is formed and the electrolytic surface roughening becomes uneven. Therefore, the content of Fe is 0.2 to 0.5% by mass. Fe has the effect of increasing the mechanical strength of an aluminum alloy. If the Fe content is less than 0.2% by mass, the mechanical strength is too low, and the lithographic printing plate is cut off when mounted on a plate cylinder of a printing press. Easily occur. On the other hand, when the content exceeds 0.5% by mass, the strength becomes higher than necessary, and when the lithographic printing plate is attached to a plate cylinder of a printing press, the fitness is poor, and the plate tends to be cut during printing. Not preferred. When the strength of the support is emphasized, the Fe content should be 0.2 to
It is preferably 0.4% by mass. However, in the case of a printing plate used for proof printing, these restrictions on fitness and strength are not always important, and thus can be slightly changed from the above range.

Si forms a solid solution in Al or Al-Fe
-Si-based intermetallic compounds or Si-only precipitates are present. Si dissolved in Al acts to make the electrochemically rough surface uniform and to mainly make the depth of the electrolytic surface roughening pits uniform. By the way, Si is contained as an inevitable impurity in the Al metal as a raw material, and in some cases, the Si content may already be 0.03% by mass or more. Therefore, a content of less than 0.03% by mass is not realistic, and a small amount is often intentionally added in order to prevent variations due to differences in raw materials. However, Si
If the content is less than 0.04% by mass, the above-mentioned effect does not appear, and high-purity Al metal is required, and it becomes expensive.
It is not realistic from this point either. Conversely, when the Si content is 0.2
If the amount exceeds 0% by mass, there is a problem that severe ink stains are deteriorated when printing. Here, severe ink stain is a point-like condition that appears on printed paper, etc. as a result of the fact that when printing is interrupted many times, the ink tends to adhere to the non-image area surface of the lithographic printing plate. Or it refers to annular dirt. Therefore, the Si content is 0.04 to 0.20% by mass, preferably 0.05 to 0.10% by mass.

Cu is a very important element in controlling the electrolytic surface roughening, and makes uniform the pits and mainly the diameter of the electrolytic surface roughened pits. Pit uniformity is essential for obtaining excellent printability. Cu content is 0.
If the content is less than 005% by mass, the resistance of the surface oxide film when forming the pits electrochemically becomes too small, so that uniform pits cannot be formed. On the other hand, if the content exceeds 0.040% by mass, the resistance of the surface oxide film when forming the pits becomes excessively large, so that coarse pits are easily generated. Therefore, the Cu content is 0.005 to 0.040.
%, Preferably 0.01 to 0.02% by mass.

Conventionally, Ti has been included in order to refine the crystal structure during casting. If the Ti content exceeds 0.040% by mass, the resistance of the surface oxide film becomes too low in the electrolytic surface roughening treatment, so that a problem that uniform pits are not formed occurs. On the other hand, when the content is 0.0
If it is less than 10% by mass, since the crystal structure at the time of casting is not refined, even after finishing to a thickness of 0.1 to 0.5 mm through various steps, a trace of a coarse crystal structure at the time of casting remains, There is a problem that a remarkable defect occurs in the appearance. In the present invention, 0.010 to 0.040 mass%, preferably 0.020 to 0.030 mass% is added as an Al-Ti alloy or an Al-B-Ti alloy.

Mg has the effect of making the recrystallized structure of Al finer and the effect of improving mechanical strength such as tensile strength, fatigue strength, bending strength and heat-softening resistance. Mg is an important component that also has the effect of making the pits uniform during electrolytic surface roughening. When the Mg content is less than 0.001% by mass, the pit dispersion becomes poor, and when the Mg content exceeds 0.020% by mass, the pit dispersion also becomes poor. Therefore, M
The g content is 0.001 to 0.020 mass%, preferably 0.005 to 0.020 mass%, more preferably 0.05 mass%.
08 to 0.020% by mass.

Ni has the effect of making the pits uniform and fine during electrolytic surface roughening. If the Ni content is less than 0.005% by mass, the effect of uniformly reducing pits is insufficient. Therefore, the Ni content is 0.005 to 0.2% by mass, preferably 0.10 to 0.20% by mass.

The above-mentioned contents of Cu and Ni are not only within the above-mentioned predetermined ranges, but also satisfy the relationship represented by the above equation (1) according to the average surface roughness Ra after the surface roughening treatment. It must be in the range. By satisfying the relationship represented by the above formula (1), the resulting lithographic printing plate support has excellent printing durability, stain resistance, and surface quality. The reason will be described below.

As described above, Cu and Ni are both components having a function of controlling the pits, but Cu controls the diameter of the roughened pits, and Ni is a component that controls the finely roughened pits. It is controlled by forming it uniformly. Although the lithographic printing plate support of the present invention has been subjected to electrolytic surface roughening treatment, it is preferably subjected to mechanical surface roughening treatment before the electrolytic surface roughening treatment as described later. Since the mechanical surface roughening treatment generally gives a large undulation component to the surface of the support, if the mechanical surface roughening treatment is performed before the electrolytic surface roughening treatment, the average surface roughness Ra becomes large. Become
If the mechanical surface roughening treatment is not performed, the average surface roughness Ra decreases.

Based on this, the present inventors have obtained the following findings regarding the Cu content, the Ni content, and the average surface roughness Ra. When the average surface roughness Ra is relatively large, for example, when the average surface roughness Ra is 0.50 to 1.0 μm, the surface area of the aluminum alloy plate becomes large due to a large undulation component, so that it is necessary to form many large pits, To achieve this, the Cu content is increased and the Ni content is reduced. When the average surface roughness Ra is relatively small, for example, when it is 0.30 to 0.50 μm, it is not necessary to form many large pits because the surface area of the aluminum alloy plate is small because the undulation component is small, Conversely, the Cu content may be small in order to prevent generation of pits that are too large.

The inventor of the present invention has obtained the above-mentioned knowledge, and further has a Cu content, a Ni content, and an average surface roughness for achieving excellent printing durability, stain resistance, and surface quality. The inventors have found the relationship of the following formula (1) with the Ra and have completed the present invention. [Ni] / 10 + [Ra] / 100 ≦ [Cu] (1) Here, [Ni] and [Cu] represent Ni content and Cu content in the lithographic printing plate support, respectively, as “% by mass”. Anonymous number expressed as a unit, [Ra] is
It represents an absolute number when the average surface roughness Ra is expressed in units of “μm”. In the present invention, the average surface roughness R
a is a value obtained by the following equation (2) when the roughness curve is represented by y = f (x). In the present invention, the cutoff value λ _C for obtaining the roughness curve is 0.8 mm.

[0031]

(Equation 1)

In the lithographic printing plate support of the present invention, since each component is within a predetermined range and the above-mentioned formula (1) is satisfied, the pits are large, deep and uniform, and the adhesion to the photosensitive layer is improved. Excellent printing durability. Also, the pit is big,
Because it is deep, it has good water retention and excellent stain resistance. Furthermore, since the pits are uniform and there are no roughened portions, the surface quality is excellent.

In the present invention, the Al purity is at least 99.0% by mass, preferably at least 99.4% by mass. Therefore, the content obtained by subtracting the Al purity (content) and the specific content of the essential alloy component is the content of the inevitable impurities. The mechanical strength of an aluminum alloy depends on the Al purity. Generally, the lower the Al purity, the lower the flexibility of the aluminum alloy. Therefore, if the purity is too low, there arises a problem that the mountability of the lithographic printing plate support on a printing press becomes poor.

In order to use an aluminum alloy as a plate material, for example, the following method can be adopted. First, a molten aluminum alloy adjusted to a predetermined alloy component is subjected to a cleaning treatment and cast according to a conventional method. In the cleaning treatment, a flux treatment, a degassing treatment using an Ar gas, a Cl gas, or the like to remove unnecessary gases such as hydrogen in the molten metal,
Processing is performed using a so-called rigid media filter such as a ceramic tube filter or a ceramic foam filter, a filter using alumina flakes or alumina balls as a filter material, a glass cloth filter, or a combination of degassing and filtering.

Then, the molten aluminum alloy is cast by any one of a casting method using a fixed mold typified by a DC casting method and a casting method using a drive mold typified by a continuous casting method. In the case of DC casting, the plate thickness is 300 to 800
Since a 1 mm ingot is produced, 1 to 30 mm, preferably 1 to 10 mm of the surface layer is cut by facing in a conventional manner. Thereafter, a soaking process is performed as necessary. When performing the soaking treatment, heat treatment is performed at 450 to 620 ° C. for 1 to 48 hours so that the intermetallic compound is not coarsened. When the time is less than 1 hour, the effect of the soaking treatment may be insufficient.

Thereafter, hot rolling and cold rolling are performed to obtain a rolled aluminum alloy plate. The starting temperature of hot rolling is suitably from 350 to 500C. Before or after, or during, the cold rolling, an intermediate annealing treatment may be performed. The conditions were 280 using a batch annealing furnace.
６００600 ° C. for 2-20 hours, preferably 350-500
At 2 ° C. for 2 to 10 hours or 40 ° C. using a continuous annealing furnace.
6 minutes or less at 0-600 ° C, preferably 450-550 ° C
For 2 minutes or less. 10 using a continuous annealing furnace
Heating at a rate of temperature rise of not less than ° C./sec can also make the crystal structure fine. Predetermined thickness, for example, 0.1 to 0.5
The flatness of the aluminum alloy plate finished in mm may be further improved by a straightening device such as a roller leveler or a tension leveler. Further, in order to process the sheet into a predetermined width, the sheet is usually passed through a slitter line.

The aluminum alloy plate is then subjected to a surface roughening treatment so as to be used as a lithographic printing plate support. The aluminum alloy plate of the present invention is subjected to a surface roughening treatment including an electrolytic surface roughening treatment, but may be subjected to only the electrolytic surface roughening treatment, and may be subjected to an electrolytic surface roughening treatment and a mechanical surface roughening treatment. Alternatively, it may be performed in combination with a chemical surface roughening treatment. Among them, it is preferable to combine the electrolytic surface roughening treatment and the mechanical surface roughening treatment, and it is particularly preferable to perform the electrolytic surface roughening treatment after the mechanical surface roughening treatment.

The electrolytic surface roughening treatment is suitable for producing a lithographic printing plate having excellent printability, since it is easy to provide fine irregularities (pits) on the surface of the aluminum alloy plate. The electrolytic surface-roughening treatment is performed in an aqueous solution mainly containing nitric acid or hydrochloric acid, using direct current or alternating current.

The average diameter is about 0.2 to
Craters or honeycomb-shaped pits of 20 μm can be formed on the surface of the aluminum alloy plate at an area ratio of 30 to 100%. The pits have an effect of improving the resistance of the non-image portion of the printing plate to stain (stain resistance) and the printing durability. In addition, the undulating rough surface having an average surface roughness Ra of 0.35 to 1.0 μm is usually formed at the same time by the electrolytic surface roughening treatment. In the electrolytic surface roughening treatment, an amount of electricity necessary for providing sufficient pits on the surface, that is, the product of the current and the conduction time is an important condition in the electrolytic surface roughening treatment. Forming a sufficient pit with a smaller amount of electricity is preferable from the viewpoint of energy saving. In the present invention, the conditions for the electrolytic surface-roughening treatment are not limited and can be performed under general conditions, but in any case, the required amount of electricity can be greatly reduced.

The mechanical surface-roughening treatment is generally performed by forming a “waviness-like” or “wrinkle-like” rough surface having a length of about 10 to 2000 μm and a height of about 1 to 10 μm on the surface of the aluminum alloy plate. Form. The average surface roughness Ra in this case is usually
0.35 to 1.0 μm, preferably 0.40 to 0.80
μm. Mechanical roughening is capable of producing "undulating" rough surfaces more efficiently than electrochemical roughening. The average surface roughness Ra is a factor indicating the undulation state of the support surface. As the average surface roughness Ra increases, the unevenness becomes larger and the water retention becomes better. Since water retention affects the entanglement of halftone dots in the stain resistance, the average surface roughness Ra ultimately affects the stain resistance. The conditions for the mechanical surface-roughening treatment in the present invention are not particularly limited, but they can be carried out according to the method described in JP-B-50-40047. The shape and size of the formed pits are almost the same as those in the case of the electrolytic surface roughening treatment. Also, the chemical surface roughening treatment is not particularly limited, and can be performed according to a known method, and undulations and pits similar to those in the case of the mechanical surface roughening treatment are formed.

Following the surface roughening treatment, an anodic oxidation treatment is performed to enhance the wear resistance of the surface of the aluminum alloy plate. The electrolyte used in this case may be any as long as it forms a porous oxide film. Generally, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixture thereof is used. The concentration of the electrolyte is appropriately determined depending on the type of the electrolyte. The conditions of the anodizing treatment vary considerably depending on the electrolyte and are therefore difficult to specify, but generally the concentration of the electrolyte is 1 to 80% by mass and the liquid temperature is 5 to 70%.
° C, current density 1-60A / dm ² , voltage 1-100V,
The electrolysis time may be 10 to 300 seconds.

Further, in order to improve the stain performance at the time of printing, after performing electrolytic surface roughening treatment and water washing, light etching treatment with an alkali solution, washing with water, desmutting with sulfuric acid, and washing with water are performed. Then, DC electrolysis may be performed in sulfuric acid to form an anodic oxide film. Further, if necessary, a hydrophilization treatment using a silicate or the like may be performed.

As described above, the lithographic printing plate support of the present invention is obtained. However, since the support has high uniformity of pits, the lithographic printing plate using the same has excellent printing performance. To prepare a lithographic printing plate, a photosensitive agent may be applied to the surface and dried to form a photosensitive layer. The photosensitive agent is not particularly limited, and those usually used for photosensitive lithographic printing plates can be used. Then, by printing the image using a lith film, and performing a developing process and a gumming process, a printing plate that can be attached to a printing machine can be obtained.
If a photosensitive layer having high sensitivity is provided, an image can be directly printed using a laser.

Any photosensitive agent may be used as long as its solubility or swelling property in a developing solution before and after exposure changes. The representative ones are listed.

(1) Photosensitive layer composed of o-quinonediazide compound The positive photosensitive compound includes o-quinonediazide compounds represented by o-naphthoquinonediazide compounds. As the o-naphthoquinonediazide compound, there are described 1,2- (2) -phthalocyanine compounds described in JP-B-43-28403.
Esters of diazonaphthoquinone sulfonic acid chloride with a pyrogallol-acetone resin are preferred. Also preferred are the esters of 1,2-diazonaphthoquinone sulfonic acid chloride and phenol-formaldehyde resin described in U.S. Pat. Nos. 3,046,120 and 3,188,210. Other known o-naphthoquinonediazide compounds can also be used.

Particularly preferred o-naphthoquinonediazide compounds are compounds obtained by reacting a polyhydroxy compound having a molecular weight of 1,000 or less with 1,2-diazonaphthoquinonesulfonic acid chloride. 1,2-diazonaphthoquinonesulfonic acid chloride is added at a ratio of 0.2 to 1.2 equivalents to 1 equivalent of the hydroxyl group of the polyhydroxy compound,
In particular, it is preferable to react at a ratio of 0.3 to 1.0 equivalent. As the 1,2-diazonaphthoquinonesulfonic acid chloride, 1,2-diazonaphthoquinone-5-sulfonic acid chloride is preferable, but 1,2-diazonaphthoquinone-4-sulfonic acid chloride can also be used.

The o-naphthoquinonediazide compound is 1,
A mixture of 2-diazonaphthoquinone sulfonic acid chlorides having various substituent positions and introduced amounts is obtained, and the ratio of all hydroxyl groups converted to 1,2-diazonaphthoquinone sulfonic acid ester to the mixture (completely esterified) Is preferably 5 mol% or more, particularly preferably 20 to 90 mol%.

Further, as the photosensitive compound which acts positively without using the o-naphthoquinonediazide compound, for example, a polymer having an o-nitrocarbinol ester group described in JP-B-56-2696 can be used. It is. Further, a compound that generates an acid by photolysis,
-CO-C- group or -CO-S dissociated by acid
A combination system with a compound having an i-group can also be used. For example, a combination of a compound that generates an acid by photolysis with an acetal or an O, N-acetal compound (Japanese Patent Application Laid-Open No. 48-90303), a combination with an orthoester or amide acetal compound (Japanese Patent Application Laid-Open No.
120714) and a combination with a polymer having an acetal or ketal group in the main chain (JP-A-53-133).
No. 429), a combination with an enol ether compound (JP-A-55-12995), a combination with an N-acylimino carbon compound (JP-A-55-126236).
No.), a combination with a polymer having an orthoester group in the main chain (JP-A-56-17345), a combination with a silyl ester compound (JP-A-60-10247)
And a combination with a silyl ether compound (JP-A-6
0-37549, JP-A-60-112446) and the like.

The proportion of the positive photosensitive compound (including the above-mentioned combination system) in the photosensitive composition of the photosensitive layer is preferably from 10 to 50% by mass, more preferably from 15 to 40% by mass.

Although the o-quinonediazide compound alone can constitute the photosensitive layer, it is preferably used together with a resin soluble in alkaline water as a binder.
Novolak resins are examples of resins soluble in alkaline water, such as phenol-formaldehyde resin and m-
Cresol-formaldehyde resin, p-cresol-
Formaldehyde resin, m- / p-mixed cresol-formaldehyde resin, phenol / cresol mixture (m
-, P-, m- / p-mixtures)-cresol-formaldehyde resin such as formaldehyde resin, phenol-modified xylene resin, polyhydroxystyrene, polyhalogenated hydroxystyrene,
Acrylic resin containing a phenolic hydroxyl group as disclosed in Japanese Patent Application Laid-Open No. 2-866.
Various alkali-soluble polymers such as an acrylic resin having a sulfonamide group and a urethane resin described in Japanese Patent Application Laid-Open Publication No. H11-209,036 can be contained. The alkali-soluble polymer preferably has a weight average molecular weight of 500 to 20,000 and a number average molecular weight of 200 to 60,000.

The alkali-soluble polymer contained 7% of the total composition.
0% by mass or less is contained. Further, U.S. Pat.
As described in Japanese Patent No. 3,279, the polycondensation of a phenol having an alkyl group having 3 to 8 carbon atoms as a substituent such as a t-butylphenol-formaldehyde resin and an octylphenol-formaldehyde resin with formaldehyde. It is preferable to use the obtained resin in combination because the oil sensitivity of the image is improved.

The photosensitive composition contains a cyclic acid anhydride for enhancing the sensitivity, a printing-out agent for obtaining a visible image immediately after exposure, a dye as an image coloring agent, and other fillers. Can be. Cyclic anhydrides are disclosed in U.S. Pat.
No. 115,128, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy- 無水⁴ -tetrahydrophthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride Chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like. The cyclic acid anhydride is used in an amount of 1 to 15 relative to the weight of the total composition.
By making the content by mass%, the sensitivity can be increased up to about three times. As a printing-out agent for obtaining a visible image immediately after exposure, a combination of a photosensitive compound that releases an acid upon exposure and an organic dye capable of forming a salt can be exemplified.

More specifically, o-type compounds described in JP-A-50-36209 and JP-A-53-8128 are disclosed.
Combinations of naphthoquinonediazide-4-sulfonic acid halogenides and salt-forming organic dyes and JP-A-53-3623
No. 3, JP-A-54-74728, JP-A-SHO60
-3626, JP-A-61-143748,
JP-A-61-151644, JP-A-63-584
No. 40, a combination of a trihalomethyl compound and a salt-forming organic dye. Dyes other than the above-mentioned salt-forming organic dyes can also be used as colorants for images. Suitable dyes, including salt-forming organic dyes, are oil-soluble dyes and basic dyes.

Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 6
03, Oil Black BY, Oil Black BS, Oil Black T-505 (all are manufactured by Orient Chemical Industries, Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (C
I42535), rhodamine B (CI45170B),
Malachite green (CI42000), methylene blue (CI52015) and the like can be mentioned. Dyes described in JP-A-62-293247 are particularly preferred.

The photosensitive composition is applied to a support by dissolving in a solvent in which the above-mentioned components are dissolved. Examples of the solvent include ethylene dichloride, cyclohexanone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, 1-methoxy-2-propanol,
Methoxy-2-propyl acetate, toluene, methyl acetate, methyl lactate, ethyl lactate, dimethyl sulfoxide, dimethylacetamide, dimethylformamide,
Examples include water, N-methylpyrrolidone, tetrahydrofurfuryl alcohol, acetone, diacetone alcohol, methanol, ethanol, isopropanol, diethylene glycol, dimethyl ether and the like. These can be used in combination.

The component (solid content) in the solution is 2 to 5
0% by mass. Although the amount of application varies depending on the application, for example, in the case of a photosensitive lithographic printing plate, a solid content of 0.5 to 3.0 g / m ² is generally preferred. The photosensitivity increases as the coating amount decreases, but the physical properties of the photosensitive film decrease.

The photosensitive composition contains a surfactant, for example, a fluorine-based surfactant as described in JP-A-62-170950, in order to improve coatability. The preferred content is 0.01 to 1 of the total photosensitive composition.
% By mass, preferably 0.05 to 0.5% by mass.

(2) Photosensitive Layer Consisting of Diazo Resin and Binder Negative-acting photosensitive diazo compounds are described in US Pat. No. 2,063,631 and US Pat.
No. 7,415, the condensation product of diphenylamine-p-diazonium salt, which is a reaction product of a diazonium salt with an organic condensing agent having a reactive carbonyl group such as aldol or acetal, and formaldehyde ( A so-called photosensitive diazo resin) is preferably used.

Other useful condensed diazo compounds are described in JP-B-49
-48001, JP-B-49-45322,
It is described in JP-B-49-45323 and the like. Since this type of photosensitive diazo compound is usually obtained in the form of a water-soluble inorganic salt, it can be applied as an aqueous solution. Further, a water-soluble diazo compound is reacted with an aromatic or aliphatic compound having one or more phenolic hydroxyl groups, sulfonic acid groups or both by a method described in JP-B-47-1167, and The product, a substantially water-insoluble photosensitive diazo resin, can also be used.

The content of the diazo resin is 5 to 5 in the photosensitive layer.
The content is preferably 0% by mass. When the content is reduced, the photosensitivity naturally increases, but the stability with time decreases. The optimum diazo resin content is about 8-20% by weight. On the other hand, as the binder, those containing a hydroxyl group, an amino group, a carboxyl group, an amide group, a sulfonamide group, an active methylene group, a thioalcohol group, or an epoxy group, from which various polymers can be used, are preferable.

Specifically, British Patent No. 1,350,52
No. 1,460,978 and US Pat. No. 4,12.
Polymers containing hydroxyethyl (meth) acrylate units as the main repeating unit as described in US Pat. No. 3,276, polyamide resins described in US Pat. No. 3,751,257, British Patent 1st, 0th
Phenolic resins described in U.S. Pat. No. 74,392, and polyvinyl acetal resins such as, for example, polyvinyl formal resins and polyvinyl butyral resins, linear polyurethanes described in U.S. Pat. No. 3,660,097. Resins, phthalated resins of polyvinyl alcohol, epoxy resins obtained from bisphenol A and epichlorohydrin, polymers containing amino groups such as polyaminostyrene and polyalkylamino (meth) acrylate, cellulose acetate, cellulose alkyl ether, cellulose acetate phthalate, etc. Cellulose derivatives are included.

The composition comprising a diazo resin and a binder further comprises a pH indicator as described in GB 1,041,463, US Pat.
It can contain additives such as phosphoric acid and dyes described in US Pat. No. 6,646.

The thickness of the photosensitive layer is 0.1 to 30 μm, more preferably 0.5 to 10 μm. The amount of the photosensitive layer provided on the support (solid content) is from about 0.1 to about 7 g / m ^2, preferably 0.5-4 g / m ^2. After the lithographic printing plate is image-exposed, a resin image is formed by a process including development by a conventional method. For example, in the case of a positive photosensitive lithographic printing plate having a photosensitive layer (A), after image exposure, U.S. Pat. No. 4,259,434 and JP-A-3-903.
By developing with an alkaline aqueous solution as described in JP-A-88-88, the exposed portion of the photosensitive layer is removed to obtain a lithographic printing plate.

In the case of a negative photosensitive lithographic printing plate having a photosensitive layer (B) composed of a diazo resin and a binder,
After image exposure, development is performed with a developing solution as described in, for example, US Pat. No. 4,186,006, whereby the unexposed photosensitive layer is removed to obtain a lithographic printing plate. Further, JP-A-5-2273 or JP-A-Hei-4
In the case of a negative photosensitive lithographic printing plate described in JP-A-219759, development can be performed with an aqueous solution of an alkali metal silicate as described in the publication.

[0065]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. 1. Production of lithographic printing plate support (Examples 1 to 8 and Comparative Examples 1 to 8) 0.28% by mass of Fe, 0.08% by mass of Si, and 0.030% by mass of Ti
An aluminum alloy plate containing 0.012% by mass of Mg and Mg and containing Cu and Ni at the ratios shown in Table 1 was produced. About the obtained aluminum alloy plate, about Examples 1-4 and comparative examples 1-4, process A shown in Table 2 was performed, and Examples 5-8 and comparative example 5
For Nos. To 9, the treatment B shown in Table 2 was performed to obtain a lithographic printing plate support.

The conditions of each process in processes A and B are as follows:
It is as follows. The surface roughening treatment with a brush uses three No. 8 brushes (material: nylon, brush bristle diameter: 0.5 mm) and a pamistone suspension at a rotational speed of 250 rpm.
Performed for 0.5 seconds. The alkali etching treatment was performed using a solution having a caustic soda concentration of 26% by mass, an aluminum ion concentration of 6.5% by mass, and a liquid temperature of 65 ° C. as an etching solution. The electrolytic surface-roughening treatment was performed with an alternating current using a solution having a sulfuric acid concentration of 1% by mass and an aluminum ion concentration of 0.5% by mass as an electrolytic solution. The anodic oxidation treatment was performed by using a 15% by mass sulfuric acid solution as an electrolytic solution with a direct current.

The average surface roughness Ra of the obtained lithographic printing plate support was about 0.6 μm for Examples 1-4 and Comparative Examples 1-4, and about 0.6 μm for Examples 5-8 and Comparative Examples 5-9. Was about 0.3 μm. The average surface roughness Ra
Is based on JIS B0601-1994,
With a cut-off value λ _C = 0.8 mm, a measuring length of 3.0 m was measured using a surface roughness meter ([Surfcom], manufactured by Tokyo Seimitsu).
m, vertical magnification 10000 times, horizontal direction magnification 50 times,
The measurement was performed at a measurement speed of 0.3 mm / sec.

2. Evaluation of Surface Quality The surface quality of the obtained lithographic printing plate support was evaluated by the following method. The evaluation was performed by visually performing a sensory evaluation on a small number of fine glossy portions on the surface. If there is no minute glossy part on the surface, it is ○, and if it is very large, it is ×, and in the middle, ○ △, △, △ ×
And a pass level of ○ △ or higher.

3. Preparation of photosensitive lithographic printing plate The lithographic printing plate support obtained in each of Examples and Comparative Examples was coated with a photosensitive agent composition having the following composition at a coating amount of 2.5 after drying.
g / m ^2, and then applied and dried to form a photosensitive layer to obtain each photosensitive lithographic printing plate. <Photosensitizer composition> Esterified product of naphthoquinone-1,2-diazide-5-sulfonyl chloride, pyrogallol, and acetone resin (described in Example 1 of US Pat. No. 3,635,709) 0 0.75 g cresol novolak resin 2.00 g Oleyl Blue # 603 (manufactured by Orient Chemical Industries) 0.04 g ethylene dichloride 16 g 2-methoxyethyl acetate 12 g

4. Printing Test The obtained photosensitive lithographic printing plate was exposed through a transparent positive film for 50 seconds with a 3 kW metal halide lamp through a transparent positive film in a vacuum printing frame, and then exposed to a 5.26% by mass aqueous solution of sodium silicate (SiO _2). / Na ₂ O =
1.74 (molar ratio, pH 12.7). After the development, the film was sufficiently washed with water, gummed, and printed by a conventional procedure.

5. Evaluation of printing durability and stain resistance Printing durability and stain resistance were evaluated by the following methods. (1) Printing durability Depending on the number of prints until the solid image portion starts to fade faintly,
It was evaluated on a five-point scale. : 100,000 or more sheets △: 95,000 to less than 100,000 sheets ：: 90,000 to less than 95,000 sheets ×: 85,000 to less than 90,000 sheets ×: 85,000 Less than

(2) Stain Resistance Stain resistance was evaluated based on blanket stain and entanglement of halftone dots. Blanket stain The stain condition of the blanket after printing 1,000 sheets was visually observed and evaluated on a five-point scale. From the one with less dirt, ○,
○ △, △, △ ×, ×. Entanglement of halftone dots The printing test similar to the above was performed by gradually reducing the amount of dampening solution, and the ink began to adhere between the halftone dots with respect to the halftone portion having an area ratio of 50%. Five levels were evaluated based on the amount of dampening water. From the one where the amount of dampening water where ink started to adhere is small,
○, ○ △, △, △ ×, ×. Depending on the printing site,
In some cases, printing is performed with an amount smaller than the standard dampening solution. In such a case, it is preferable that ink does not adhere between the halftone dots. One.

Table 1 shows the results of the surface quality, printing durability and stain resistance of each lithographic printing plate support. Comparative Examples 1 to 9
, The underlined part falls outside the scope of the present invention. In the lithographic printing plate support of the present invention, the Cu content and the Ni content are adjusted so as to satisfy the above formula (1) in accordance with the average surface roughness Ra. And the surface has little unetched (unsatisfactory surface roughening), and as a result, is excellent in all of the surface quality, printing durability and stain resistance (evaluated by blanket stains and halftone dots). (Examples 1 to 8). On the other hand, when the Cu content is less than the range of the present invention, the printing durability and the tangling of halftone dots are inferior (Comparative Examples 1, 5 and 6). In addition, when the Cu content and the Ni content do not satisfy the above formula (1), the printing durability, blanket stain, and halftone dot entanglement are inferior, and the surface quality is also inferior (Comparative Examples 2 to 4). 4 and 7).
Comparative Example 8 satisfies the expression (1), but the pits could not be uniform because the Ni content was outside the range of the present invention.
Inferior to blanket dirt. Further, Comparative Example 9 is based on the formula (1)
However, since the Cu content is too large, the pits become too coarse, resulting in poor surface quality, blanket stain and halftone dot entanglement.

[0074]

[Table 1]

[0075]

[Table 2]

[0076]

The lithographic printing plate support of the present invention has large, deep and uniform pits obtained by the electrolytic surface roughening treatment, and therefore has excellent adhesion to the photosensitive layer and excellent printing durability. . Further, since the pits are large and deep, the water retention is good and the stain resistance is excellent. Furthermore, since the pits are uniform and there are no roughened portions, the surface quality is excellent.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one example of an interface between a support of a conventional lithographic printing plate precursor and a photosensitive layer. (A) shows before exposure, (b) shows during exposure, and (c) shows after exposure.

FIG. 2 is a cross-sectional view schematically showing another example of the interface between the support of the conventional lithographic printing plate precursor and the photosensitive layer. (A) shows before exposure, (b) shows during exposure, and (c) shows after exposure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Conventional lithographic printing plate precursor 12 Support 14 Photosensitive layer p pit p 'Non-uniform pit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H025 AB03 DA18 DA20 DA36 EA01 2H096 AA07 CA03 CA20 2H114 AA04 AA11 AA14 AA27 BA01 DA04 DA73 EA03 EA08 FA06 GA09

Claims (1)

[Claims] (1) 0.2-0.5% by mass of Fe and 0.1% of Si.
04 to 0.20 mass%, 0.005 to 0.040 Cu
% By mass, 0.010 to 0.040% by mass of Ti, 0.001 to 0.020% by mass of Mg, and 0.00% of Ni.
A lithographic printing plate support obtained by subjecting an aluminum alloy plate containing 5 to 0.2% by mass and a balance of Al and inevitable impurities to a surface roughening treatment including an electrochemical surface roughening treatment. , Ni content: [Ni] (% by mass), Cu content: [Cu] (% by mass), and average surface roughness Ra: [R
a] (μm), wherein the support satisfies the following formula (1): [Ni] / 10 + [Ra] / 100 ≦ [Cu] (1)