JP2002211158A - Method for manufacturing support for lithographic printing plate and alkali etching treating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a support for a lithographic printing plate for suppressing reductions in a liquid fatigue and a thickness of an aluminum plate without bringing about a problem in an appearance of a rear surface even when any aluminum plate is used. SOLUTION: The method for manufacturing the support for the lithographic printing plate comprises an alkali etching step. In this case, an etching amount of the rear surface of the support is 1.5 g/m2 or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a lithographic printing plate support used for offset printing and the like, and an alkaline etching apparatus.

[0002]

2. Description of the Related Art A lithographic printing plate support is usually obtained by subjecting an aluminum plate to a surface roughening treatment and an anodic oxidation treatment. The pits formed on the surface of the aluminum plate by the surface roughening treatment are uniformly removed. In general, an alkali etching process is performed for the purpose of, for example, performing an etching process. The alkali etching treatment is usually performed by spraying an aqueous solution of an alkali such as caustic soda on the surface of an aluminum plate subjected to a surface roughening treatment. FIG. 1 is a schematic sectional view showing an example of an alkali etching treatment apparatus. As shown in FIG. 1, in a conventional alkaline etching apparatus 100, an alkaline aqueous solution is sprayed on a surface by a spray 102 while an aluminum plate 1 passes between several rolls 101 arranged in zigzag. You.

[0003]

However, the alkaline aqueous solution sprayed on the front surface wraps around from the both ends of the aluminum plate 1 to the back surface, and further accumulates in the space 103 between the lower roll 101 and the aluminum plate 1. The entire back surface of the aluminum plate 1 is also etched by the alkaline aqueous solution. When the back surface is etched in this manner, particularly, when using an aluminum plate obtained by a continuous casting method or an aluminum plate obtained by a DC casting method or the like and omitting intermediate annealing or soaking treatment, In some cases, appearance problems such as streaks and unevenness may occur on the back surface. Further, when the back surface is etched, the liquid fatigue of the etching solution may become too large, or the thickness of the aluminum plate may be greatly reduced. Therefore, the present invention does not cause the above-described problem of the appearance of the back surface regardless of the type of aluminum plate used, and
An object of the present invention is to provide a method of manufacturing a lithographic printing plate support in which liquid fatigue and a decrease in the thickness of an aluminum plate are suppressed, and an alkali etching apparatus suitably used in the method.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventor has found that if the amount of etching on the back surface is set to a specific amount or less, the appearance of the above-mentioned back surface can be improved regardless of the type of aluminum plate used. It has been found that the problem described above does not occur, and that liquid fatigue and reduction in the thickness of the aluminum plate are suppressed, and the present invention has been completed. That is, the present invention provides a method for producing a lithographic printing plate support having an alkali etching step, wherein the amount of etching on the back surface is 1.5 g / m ² or less. .

[0005] The present invention also provides an alkali etching apparatus in which the amount of etching on the back surface is 1.5 g / m ² or less.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. <Aluminum plate (rolled aluminum)> The aluminum plate used in the present invention is a dimensionally stable metal containing aluminum as a main component, and is made of aluminum or an aluminum alloy. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and a trace amount of a different element, or a plastic film or paper on which aluminum or an aluminum alloy is laminated or vapor-deposited can be used. Further, a composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in JP-B-48-18327 can also be used.

In the following description, various substrates made of aluminum or an aluminum alloy mentioned above are collectively used as an aluminum plate. The foreign elements that may be included in the aluminum alloy include silicon, iron, manganese,
There are copper, magnesium, chromium, zinc, bismuth, nickel, titanium and the like, and the content of the foreign element in the alloy is 10% by mass or less.

In the present invention, it is preferable to use a pure aluminum plate. However, since pure aluminum is difficult to produce due to refining technology, it may contain a slightly different element. As described above, the composition of the aluminum plate used in the present invention is not specified, and a conventionally known and used material, for example, JIS A105
0, JIS A1100, JIS A3103, JIS
A3005, JISA3004, Internationally registered alloy 31
An aluminum alloy plate such as 03A can be used as appropriate. Of these, JIS A1050 and JIS A
Table 1 shows the composition of 3005. Further, in the present invention, an aluminum alloy plate having a large content of a different element as in Example 1 shown in Table 1 can be used.

[0009]

[Table 1]

The method for producing an aluminum plate may be either a continuous casting method or a DC casting method, and an aluminum plate which does not include the DC casting intermediate annealing or the soaking treatment can be used. As will be described later, according to the method for producing a lithographic printing plate support of the present invention, an aluminum plate obtained by a continuous casting method, an aluminum plate obtained by a DC casting method, etc. Even if the surface treatment is omitted, no problem in appearance such as stripes or unevenness occurs on the back surface of the resulting lithographic printing plate support. In the final rolling, an aluminum plate having irregularities by lamination rolling, transfer, or the like can be used. Also,
The thickness of the aluminum plate used in the present invention is 0.1 m.
m to about 0.6 mm. This thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, and the desire of the user.

The method for producing a lithographic printing plate support of the present invention includes a step of subjecting the aluminum plate to an alkali etching treatment, and further includes various steps such as a surface roughening treatment and an anodic oxidation treatment. Alternatively, the order of the various steps is not particularly limited. Hereinafter, preferred embodiments of the present invention will be described.

<Roughening (Graining)> The aluminum plate is grained to a more preferable shape. Examples of the graining method include mechanical graining (mechanical graining treatment), chemical etching, electrolytic grains, and the like as disclosed in JP-A-56-28893.
Furthermore, an electrochemical graining method (electrochemical graining treatment, electrolytic graining treatment) for electrochemical graining in hydrochloric acid electrolyte or nitric acid electrolyte, or scratching the aluminum surface with a metal wire A mechanical graining method such as a brush grain method, a ball grain method of sanding the aluminum surface with a polishing ball and an abrasive, and a brush grain method of sanding the surface with a nylon brush and an abrasive can be used. These graining methods can be used alone or in combination.

<Mechanical Surface Roughening Treatment> The mechanical surface roughening treatment is performed, for example, by a method described in Japanese Patent Application Laid-Open No. 6-135175 and Japanese Patent Publication No. 50-40047. It is advantageous to perform mechanical surface roughening treatment with a rotating nylon brush roll having a hair diameter of 0.2 to 0.9 mm and a slurry liquid supplied to the surface of the aluminum plate. A method of spraying a slurry liquid, a method of using a wire brush, a method of transferring the surface shape of a roll provided with irregularities to an aluminum plate, or the like may be used.

In the mechanical surface roughening treatment, first, prior to the brush graining, if necessary, a degreasing treatment for removing rolling oil on the surface of the aluminum plate, for example, a surfactant, an organic solvent, an alkaline A degreasing treatment with an aqueous solution or the like may be performed. Subsequently, using one type or at least two types of brushes having different hair diameters,
While supplying the polishing slurry liquid to the aluminum plate surface,
Perform brush graining. The brush used first in the brush graining is referred to as a first brush, and the brush used last is referred to as a second brush. At the time of the graining, as shown in FIG. 2, the roller-like brushes 2 and 4 and the two support rollers 5, 6, 7, and 8 are arranged with the aluminum plate 1 interposed therebetween. The two support rollers 5, 6 and 7, 8 are arranged such that the shortest distance between their outer surfaces is equal to that of the roller brush 2.
And aluminum plates 1 are arranged so as to be smaller than the outer diameters of the rollers 4 and 4, respectively. The aluminum plate 1 is pressed by the roller-like brushes 2 and 4, and is pressed between the two support rollers 5, 6 and 7, 8. It is preferable that the surface of the aluminum plate is polished by transporting the aluminum plate at a constant speed, supplying the polishing slurry liquid 3 onto the aluminum plate, and rotating the roller brush.

As the brush used in the present invention, a brush-like material such as nylon, polypropylene, animal hair, steel wire or the like is implanted in a roller-shaped base with a uniform hair length and a flocking distribution, and a small hole is formed in the base. A brush hair bundle is implanted, and a channel roller type is preferably used. Among them, a preferable material is nylon, and a preferable hair length after flocking is 10 to 200 mm.
The preferred hair diameter is 0.24-0.83 mm, more preferably 0.295-0.6 mm. The cross-sectional shape of the hair is preferably a circle. If the hair diameter is less than 0.24 mm, the stain performance in the shadow part may be deteriorated,
If it exceeds 0.83 mm, the blanket cylinder may become dirty. The material of the bristle is preferably nylon, and nylon 6, nylon 6.6, nylon 6,10, etc. are suitably used. Tensile strength, abrasion resistance, dimensional stability by water absorption, bending strength, heat resistance Nylon 6/10 is most preferable in terms of properties, recoverability and the like.

The number of brushes is preferably 1 to 10, more preferably 1 to 6. The brush roller may be a combination of brush rollers having different bristle diameters as described in JP-A-6-135175. A support roller having a rubber or metal surface and having a good straightness is used. The rotation direction of the brush rollers is preferably performed in a forward direction with respect to the transport direction of the aluminum plate, as shown in FIG.

Known abrasives can be used for the abrasive used in the present invention. For example, abrasives such as pumice stone, silica sand, aluminum hydroxide, alumina powder, volcanic ash, carborundum, diamond sand, or a mixture thereof can be used. Among them, the average particle size is 5 to 150 μm, the specific gravity is 1.05 to
Abrasives of 1.3 are preferred.

<Electrochemical surface-roughening treatment> The electrochemical surface-roughening treatment is an aqueous solution mainly containing hydrochloric acid or nitric acid for the purpose of obtaining unevenness having a uniform size and a uniform distribution without overlapping. It is performed using alternating current or direct current. As the aqueous solution mainly composed of hydrochloric acid, one used for electrochemical surface roughening treatment using a normal alternating current can be used, and aluminum chloride, sodium chloride, ammonium chloride, hypochlorite is added to an aqueous solution of hydrochloric acid of 1 to 100 g / L. A chlorine compound having a chloride ion such as sodium acid can be used by adding it in an amount of 1 g / L or more and up to saturation. Further, in the aqueous solution mainly composed of hydrochloric acid, metals contained in aluminum alloys such as iron, copper, manganese, nickel, titanium, magnesium and silica may be dissolved. Temperature is 20-50 ° C
And more preferably 30 to 40 ° C.

FIG. 3 shows a trapezoidal wave which is an example of an alternating current used for the electrochemical surface roughening treatment in the present invention. The time (TP) from the time when the current reaches 0 to the peak is preferably 0.5 to 2 msec. If it is shorter than 0.5 msec, processing irregularities such as chatter marks generated perpendicularly to the traveling direction of the aluminum plate are likely to occur. If the TP is longer than 2 msec, the electrolytic treatment in a nitric acid solution typified by ammonium ions or the like in the electrolytic solution used for the electrochemical graining treatment is susceptible to the spontaneously increasing trace components. This makes it difficult to perform a uniform roughening process. As a result, the stain performance tends to decrease. A duty ratio of trapezoidal wave alternating current of 1: 2 to 2: 1 can be used.
In the indirect power supply system using no conductor roll for aluminum as described in Japanese Patent Publication No. 300, a duty ratio of 1: 1 is preferable. The frequency of trapezoidal wave AC is 50 ~
The frequency is preferably 150 Hz, more preferably 60 to 120 Hz.

This electrolytic surface roughening treatment is described in JP-A-1-141.
An electrochemical graining treatment using a direct current as described in JP-A-0994 may be used. In the DC surface roughening treatment, an electrochemical surface roughening treatment is performed in an acidic aqueous solution using a DC voltage. In order to perform electrochemical graining treatment using a DC voltage in an acidic aqueous solution, an electrolytic solution is filled with an acidic aqueous solution, and an anode and a cathode are alternately arranged in the acidic aqueous solution. A DC voltage is applied between the anode and the cathode, and the aluminum plate is passed through the anode and the cathode at an arbitrary interval.

As the acidic aqueous solution, those used for electrochemical surface roughening treatment using a normal alternating current can be used. For example, there are aqueous solutions mainly containing hydrochloric acid, nitric acid and the like. Among these, an aqueous solution mainly containing nitric acid is preferable. In the case of an aqueous solution mainly containing nitric acid, a nitrate compound containing nitrate ions such as aluminum nitrate, sodium nitrate and ammonium nitrate can be used. Also, aluminum salt,
It is preferable to mix one or more of ammonium salts and the like in an amount of 1 to 150 g / L. The ammonium ions also increase spontaneously by electrolytic treatment in an aqueous nitric acid solution. In addition, iron, copper,
Metals contained in aluminum alloys such as manganese, nickel, titanium, magnesium and silica may be dissolved. Further, ammonium ions, nitrate ions and the like may be added.

The concentration of the acidic aqueous solution is preferably at least 1.0 g / L and up to a saturated concentration.
g / L is more preferable. When the concentration is less than 1.0 g / L, the conductivity of the liquid becomes poor, and the electrolytic voltage may increase. If the concentration exceeds 100 g / L, a problem may occur in the corrosion resistance of the equipment. Further, the temperature of the acidic aqueous solution is preferably from 30 to 55 ° C, and is preferably from 35 to 50 ° C.
Is more preferable. When the temperature is lower than 30 ° C.,
The conductivity of the solution may be deteriorated, and the electrolytic voltage may increase. If the temperature exceeds 55 ° C., a problem may occur in the corrosion resistance of the equipment. The cathode is, for example, platinum, stainless steel,
Carbon, titanium, tantalum, niobium, zirconium,
Hafnium or an alloy thereof can be used. When titanium is used as a cathode, its surface is coated with a platinum-based metal, and then, at 400 to 10,000 ° C., 3
By performing the heat treatment for 0 to 60 minutes, a cathode having corrosion resistance can be obtained. The surface of the cathode is preferably as close as possible to a mirror surface in order to prevent an increase in electrolytic voltage due to precipitation of hydroxide.

The DC voltage in the present invention means not only a continuous DC voltage but also a commercial AC rectified by a diode, a transistor, a thyristor, a GTO or the like, a rectangular pulse DC, or the like. A voltage that does not change its polarity. In particular, a continuous DC voltage having a ripple rate of 10% or less is preferable. Current density is 20-200
A / dm ² , preferably 50 to 120 A / dm ²
More preferably, it is ² . The amount of electricity applied to the aluminum plate by the electrochemical surface roughening treatment is 10 to 1000 C / dm.
It is preferably from ^2, and more preferably 40~600C / dm ^2.

In the electrochemical surface-roughening treatment using a DC voltage, the anode and the cathode may each be constituted by one member or by combining a plurality of electrode pieces.
Since it can be manufactured easily and inexpensively, and the current distribution can be made uniform, it is preferable to configure a combination of a plurality of electrode pieces. When manufacturing by combining a plurality of electrode pieces, for example, a plurality of electrode pieces are arranged in parallel at a predetermined interval, or a plurality of electrode pieces are arranged in parallel via an insulator of about 1 to 5 mm. The shape of such an electrode piece is not particularly limited, and may be a square bar shape or a round bar shape. As the insulator, a material having both electric insulation and chemical resistance is preferable, and vinyl chloride, rubber, Teflon (registered trademark), FRP, or the like is used. Anode and cathode length L
(M) shows the passing speed of the aluminum plate as V
(M / sec), 0.05 V to 5 V (m)
It is preferred that

As the anode, an electrode obtained by plating or cladding a platinum-based electrode such as platinum on a valve metal such as titanium, tantalum or niobium, or a ferrite electrode can be used. Since it is difficult to manufacture a long electrode for a ferrite electrode, two or more electrodes are butt-connected or overlap-connected. However, since the joints may cause processing unevenness, the electrodes may be arranged along the traveling direction of the aluminum plate. Are arranged in a staggered manner so that the positions of the joints do not overlap the same position in the direction perpendicular to the traveling direction. The distance between the anode and the aluminum plate is preferably 10 to 50 mm, more preferably 15 to 30 mm.

An apparatus used for electrochemical graining treatment using a direct current uses a graining method in which a pair or more of anodes and cathodes are alternately arranged in an acidic aqueous solution and an aluminum plate is passed over the anodes and cathodes. It is advantageous.

An apparatus used for the electrochemical surface roughening treatment using a DC voltage in the present invention will be described with reference to the drawings. FIG.
In the roughening apparatus using a DC voltage shown in (1), an electrolytic cell for performing anodic electrolytic treatment on an aluminum plate is provided first, and then an electrolytic cell for performing cathodic electrolytic treatment on an aluminum plate is provided. In the apparatus shown in FIG. 5, an anode for performing cathodic electrolysis of an aluminum plate and a cathode for performing anodization of an aluminum plate are provided in one electrolytic cell.

Next, an apparatus used for electrochemical surface roughening treatment using an AC voltage in the present invention will be described with reference to the drawings. FIG. 6 shows a preferred radial type apparatus for performing electrochemical surface roughening treatment using alternating current in the present invention. In FIG. 6, 11 is an aluminum plate, and 12 is a radial drum roller supporting the aluminum plate. The aluminum plate runs while maintaining a constant clearance with main poles 13a and 13b made of carbon and an auxiliary anode 18 made of ferrite, platinum or the like provided to prevent dissolution of carbon as the main pole. Clearance is usually 3-50m
About m is appropriate. The ratio between the processing lengths of the main electrode and the auxiliary electrode and the length ratio between the main electrodes 13a and 13b differ depending on the required electrolysis conditions. The ratio of the length of the main poles 13a and 13b is 1: 2.
To 2: 1 range, but as much as possible 1: 1
It is preferable that Main pole 13a or 13
b and the processing length of the auxiliary anode 18 are 1: 1 to 1: 0.
It is preferably 1. Further, in order to suppress unevenness in the processing of horizontal stripes generated perpendicularly to the direction of movement of the aluminum plate, which is called chatter mark, low current density processing is performed as described in JP-B-63-16000. Is preferably provided at the head of the electrodes 13a and 13b. Since it is difficult to make the main pole 13 to bend (bend) along the radial drum roller 12, Japanese Patent Laid-Open No.
As described in Japanese Patent Application Laid-Open No. 195300, it is customary to arrange an insulator called a insulator with a thickness of 1 to 5 mm.

The current flowing through the auxiliary electrode is controlled by the rectifier or the switching element to a desired current value from the power supply and is divided. The rectifiers 19 are preferably thyristors 19a and 19b, and can control the current flowing through the auxiliary anode 18 at the firing angle. By distributing the current to the auxiliary anode, the dissolution of the carbon electrode of the main electrode can be suppressed, and the roughened shape in the electrochemical roughening step can be controlled. The current ratio of the current flowing through the carbon electrode to the current flowing through the auxiliary anode is preferably from 0.95: 0.05 to 0.7: 0.3.

The liquid flow may be parallel or counter to the progress of the aluminum plate, but the counter is less likely to cause processing unevenness. The electrolytic solution 14 enters the electrolytic solution supply port 15, enters the cavity via the distributor so as to be uniformly distributed over the entire width of the radial drum roller 12, and is ejected from the slit 16 into the electrolytic solution passage 17. You. As shown in FIG. 7, two or more electrolytic devices shown in FIG. 6 may be used side by side.

<Alkali Etching Treatment> The aluminum plate thus grained is chemically etched with alkali. Alkali etching treatment,
In order to remove rolling oil, dirt and natural oxide film on the surface of the aluminum plate (rolled aluminum),
For the purpose of dissolving the edge portion of the unevenness generated by the mechanical surface roughening and obtaining a surface having a smooth undulation, and quickly removing the smut component generated by the electrochemical surface roughening treatment. The purpose is to control the average diameter of the roughened pits to 0.3 to 1.0 μm.

The details of the alkali etching treatment are described in US Pat. No. 3,834,398 and the like. Examples of the alkali used for the aqueous alkali solution include sodium hydroxide, potassium hydroxide, sodium tertiary phosphate, sodium aluminate, sodium carbonate and the like, as described in JP-A-57-16918. Can be used alone or in combination. The concentration of the aqueous alkali solution is preferably from 5 to 30% by mass, and particularly preferably from 20 to 30% by mass. The concentration of aluminum dissolved in the alkaline aqueous solution is preferably 0.5 to 30% by mass. Etching with an alkaline aqueous solution is performed at a liquid temperature of 40 to 9
Preferably, the treatment is performed at 0 ° C. for 1 to 120 seconds. The amount of etching (the amount of aluminum dissolved by the etching process) is 1
３０30 g / m ² , preferably 1.5-20 g / m ²
m ² is more preferable. The alkali etching treatment is not limited to one type, and a plurality of steps can be combined. In particular, for example, when performing a roughening process a plurality of times, such as performing an electrochemical roughening process after performing a mechanical roughening process, an alkali etching process is performed after each of the roughening processes. It is preferred to do so.

In the present invention, in the above-mentioned alkali etching step, the etching amount of the back surface is set to 1.5 g / m ^2.
It is characterized as follows. When the amount of etching of the back surface is 1.5 g / m ² or less, the aluminum plate obtained by the continuous casting method or the aluminum plate obtained by the DC casting method or the like is omitted from the intermediate annealing and the soaking treatment. Even in the case of using such a material, the above-described problem of the appearance of the back surface does not occur, the liquid fatigue of the etching solution is small, and the decrease in the thickness of the aluminum plate is also small. The amount of etching on the back surface is preferably 1.0 g / m ² or less, and 0.5 g / m ² or less.
/ M ² or less. In the present invention,
In the case where the alkali etching step is performed a plurality of times, the total amount of etching is set to fall within the above range.

A method in which the etching amount of the back surface is set in the above range.
Is not particularly limited, for example, the alkali etch of the present invention
And a method using a processing device. Al of the present invention
The pot etching apparatus sets the amount of etching on the back surface to 1.
5g / m ^TwoAn alkali etching apparatus having the following configuration
You. Hereinafter, the alkaline etching apparatus of the present invention will be described with reference to the drawings.
The present invention will be specifically described with reference to
Not.

Each of the alkaline etching apparatuses of the present invention exemplified in the schematic views of FIGS. 8 and 9 includes a spray for spraying an alkaline aqueous solution on one surface of a continuously supplied metal web, and a spray of the metal web. An alkali etching treatment apparatus comprising: a coating member that covers at least both ends of the metal web in a portion on the back side of a portion where the alkali aqueous solution is sprayed.

The alkaline etching apparatus 110 shown in FIG.
In the above, the spray 111
To spray an aqueous alkaline solution. On the other hand, the back surface of the aluminum plate 1 is covered with a masking belt 112 as a covering member.
, So that the alkaline aqueous solution sprayed on the surface cannot substantially flow around. The masking belt 112 preferably covers the entire width of the aluminum plate 1, but at least the aluminum plate 1
Any material may be used as long as it covers both ends. Also, in FIG. 8, the masking belt 112 covers the entire length of the portion on the back side of the portion where the alkaline aqueous solution is sprayed, but if the etching amount on the back surface can be set to 1.5 g / m ² or less, There may be a portion that is not covered, such as an upstream portion or a downstream portion. Further, the masking belt 112 covers the upstream portion and / or the downstream portion of the portion of the aluminum plate 1 where the alkaline aqueous solution is sprayed, so that the etching is prevented by the alkaline aqueous solution scattered from the spray 111 or the alkaline aqueous solution circulating after the spraying. It is preferable in that it can be performed.

The alkaline etching apparatus 120 shown in FIG.
In the above, spray 121 is applied to the surface of aluminum plate 1.
To spray an aqueous alkaline solution. On the other hand, the back side of the aluminum plate 1
, So that the alkaline aqueous solution sprayed on the surface cannot substantially flow around. The masking roll 122 preferably covers the entire width of the aluminum plate 1, but at least the aluminum plate 1
Any material may be used as long as it covers both ends. Also, in FIG. 9, the masking roll 122 covers the entire length of the portion on the back side of the portion where the alkaline aqueous solution is sprayed, but if the etching amount on the back surface can be set to 1.5 g / m ² or less, There may be an uncoated portion in an upstream portion or a downstream portion. Further, the masking roll 122 covers the upstream portion and / or the downstream portion of the portion of the aluminum plate 1 where the alkaline aqueous solution is sprayed, so that the etching is prevented by the alkaline aqueous solution scattered from the spray 121 or the alkaline aqueous solution circulating after the spraying. It is preferable in that it can be performed.

The alkaline etching apparatus of the present invention exemplified in the schematic view of FIG. 10 is an alkaline etching apparatus in which a portion of one surface of a continuously supplied metal web except for both ends is brought into contact with an alkaline aqueous solution. . In the alkaline etching apparatus 130 of FIG. 10, the aluminum plate 1 is supplied with its surface facing down,
The surface is brought into contact with an alkaline aqueous solution filled with. Bath 1
The width of 31 is set so as to be slightly smaller than the width of aluminum plate 1, and both ends of aluminum plate 1 are arranged so as to protrude from bath 131. The alkaline aqueous solution contacts the part of the surface of the aluminum plate 1 except for the both ends, and is diffused by "wetting" to perform etching to both ends, but it is extremely unlikely that the alkaline aqueous solution goes around. The length of the bath 131 is appropriately determined according to the amount of etching of the surface. Also, although not shown, the aluminum plate is supplied with its surface facing up, and a necessary amount of an alkaline aqueous solution is supplied from above to a portion excluding both ends of the aluminum plate, and is diffused by "wetting". Alternatively, an alkaline etching apparatus for supplying an alkaline aqueous solution to both ends by leveling with a squeegee or the like is also a preferred example of the present invention.

The alkaline etching apparatus of the present invention exemplified in the schematic diagram of FIG. 11 comprises a spray for spraying an alkaline aqueous solution on one surface of a continuously supplied metal web;
A sprayer for spraying water to at least both ends of the metal web in a portion on the back side of a portion of the metal web to which the alkaline aqueous solution is sprayed. The alkaline etching apparatus 14 of FIG.
0, spray 14 on the surface of aluminum plate 1
Spray an alkaline aqueous solution according to 1. On the other hand, water is sprayed on the back surface of the aluminum plate 1 by the water spray 142 so that the alkaline aqueous solution sprayed on the surface cannot substantially flow around. The water spray 142 preferably sprays water over the entire width of the aluminum plate 1, but may be any spray that sprays water at least on both ends of the aluminum plate 1. Further, in FIG. 11, the washing spray 142 is an aqueous alkaline solution is sprayed with water over the entire length of the rear portion of the part to be sprayed, that the etching amount of the back and 1.5 g / m ² or less If possible, there may be a part where water is not sprayed in an upstream part or a downstream part.

<Electropolishing and Etching in Acidic Aqueous Solution> In the present invention, in addition to the above-described alkali etching, electrolytic polishing in an acidic aqueous solution,
Alternatively, a chemical etching treatment in an acidic aqueous solution may be performed. These treatments are for the purpose of removing rolling oil, dirt and natural oxide film on the surface of the aluminum plate (rolled aluminum), and dissolving the edge portions of the irregularities generated by the mechanical roughening, It is performed for the purpose of obtaining a surface having a smooth undulation, and further for the purpose of promptly removing the smut component generated by the electrochemical graining treatment.

For the electropolishing treatment in an acidic aqueous solution, see, for example, Fujio Mamiya: Cleaning Design, No. 21, p.
65-72 (1984) describes a formulation example of electropolishing by material. In the present invention, an aqueous solution used for a known electropolishing treatment can be used.
An aqueous solution mainly containing sulfuric acid or phosphoric acid is preferable, and an aqueous solution mainly containing phosphoric acid is more preferable.

Suitable conditions for the electropolishing treatment include a phosphoric acid concentration of 20 to 90% by mass (preferably 40 to 80% by mass), a liquid temperature of 10 to 90 ° C. (preferably 50 to 80 ° C.),
Current density 1 to 100 A / dm ² (preferably 5 to 80 A
/ Dm ² ), and the electrolysis time is from 1 to 180 seconds. Sulfuric acid, chromic acid, hydrogen peroxide, citric acid, boric acid, hydrofluoric acid, phthalic anhydride and the like may be added to the phosphoric acid aqueous solution at 1 to 50% by mass. In addition to aluminum, the alloy component contained in the aluminum alloy is 0 to 10% by mass.
It may be contained. As the current, DC, pulse DC or AC can be used, but continuous DC is preferable.

As the electrolytic treatment apparatus, those used in known electrolytic treatment such as a flat type tank and a radial type tank can be used. The direction of the flow may be either a parallel flow or a counter flow with respect to the aluminum plate, and the flow velocity is preferably 0.01 to 10000 cm / min. The distance between the aluminum plate and the electrode is 0.3 ~
It is preferably 10 cm, more preferably 0.8 to 2 cm. As a power supply method, a direct power supply method using a conductor roll may be used, or an indirect power supply method (liquid power supply method) without using a conductor roll may be used. As the electrode material and structure to be used, known materials used for electrolytic treatment can be used, but the cathode material is preferably carbon, and the anode material is ferrite,
Preferably, it is iridium oxide or platinum.

The details of the etching treatment in an acidic aqueous solution are described in US Pat. No. 3,834,398 and the like. As the acid used for the acidic aqueous solution,
As described in JP-A-57-16918, hydrofluoric acid, fluorinated zirconic acid, phosphoric acid, sulfuric acid, hydrochloric acid,
There are nitric acid and the like, and these can be used alone or in combination. The concentration of the acidic aqueous solution is preferably 0.5 to 25% by mass, particularly preferably 1 to 5% by mass. The amount of aluminum dissolved in the acidic aqueous solution is preferably 0.5 to 5% by mass. Etching with an acidic aqueous solution is preferably performed at a liquid temperature of 40 to 90 ° C. for 1 to 120 seconds. The etching amount is 1 to 30 g / m ²
And more preferably 1.5 to 20 g / m ² .

<Desmut treatment> Generally, a smut is formed on the surface of an aluminum plate by an alkali etching treatment. In this case, phosphoric acid, nitric acid, sulfuric acid, hydrochloric acid,
It is preferable to perform desmut treatment with chromic acid or a mixed acid containing two or more of these acids. The desmutting time is preferably from 1 to 30 seconds. The liquid temperature is from room temperature to 70 ° C. In the case where the alkali etching treatment is performed a plurality of times, desmutting treatment is preferably performed after each alkali etching treatment.

<Anodic Oxidation> Anodization is further applied to increase the water retention and abrasion resistance of the surface. As the electrolyte used for anodizing aluminum plate,
Any material can be used as long as it forms a porous oxide film. In general, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes can be determined as appropriate depending on the type of electrolyte. Since the anodizing treatment conditions vary depending on the electrolyte used, they cannot be specified unconditionally. In general, however, the concentration of the electrolyte is 1 to 80% by mass, the solution temperature is 5 to 70 ° C., and the current density is 1 to 60A / dm ² , voltage is 1
It is appropriate that the electrolysis time is in the range of 10 seconds to 5 minutes.

In the sulfuric acid method, the treatment is usually performed with a direct current, but an alternating current can also be used. The concentration of sulfuric acid is 5-30
%, And electrolysis at a temperature of 20 to 60 ° C. for 5 to 250 seconds. This electrolyte preferably contains aluminum ions. Further, the current density at this time is preferably ¹ to 20 A / dm ² . In the case of the phosphoric acid method, the concentration of 5 to 50 mass%, at a temperature of 30 to 60 ° C., 10 to 300 seconds, preferably being treated at a current density of 1 through 15A / dm ^2. The amount of the anodic oxide film is preferably 1.0 g / m ² or more, and 2.0 to 6.
More preferably, it is 0 g / m ² . When the amount of the anodic oxide film is less than 1.0 g / m ² , the printing durability is insufficient or the non-image portion of the lithographic printing plate is easily scratched,
So-called "scratch stains" in which ink adheres to scratches during printing are likely to occur.

<Hydrophilic treatment> After the anodic oxidation treatment, the aluminum surface is subjected to a hydrophilic treatment as required. As the hydrophilic treatment in the present invention, for example,
U.S. Pat. Nos. 2,714,066 and 3,18
There is an alkali metal silicate (for example, an aqueous solution of sodium silicate) as disclosed in 1,461, 3,280,734 and 3,902,734. In this method, the support is immersed in an aqueous solution of sodium silicate or subjected to electrolytic treatment. In addition, Japanese Patent Publication No. 36-22063
Patent No., the potassium fluoride zirconate,
U.S. Pat. Nos. 3,276,868 and 4,15
A method of treating with polyvinyl phosphonic acid as disclosed in 3,461 and 4,689,272 is used. Further, a material subjected to a sealing treatment after the electrochemical graining treatment and the anodic oxidation treatment is also preferable. Such a sealing treatment is performed by immersion in hot water and a hot aqueous solution containing an inorganic salt or an organic salt, a steam bath or the like.

The apparatus used for the electropolishing treatment in an acidic aqueous solution, the etching treatment in an acidic aqueous solution, the desmutting treatment, the washing treatment and the hydrophilizing treatment in the present invention may be immersion. For example, FIG.
A spray as shown in FIG. Further, the aluminum plate passed through the electrochemical surface roughening treatment tank, the chemical etching tank, the desmut treatment tank, the water washing treatment tank and the hydrophilic treatment tank in the present invention described above, by performing liquid removal by a nip roll, The processing can be performed uniformly in the width direction of the aluminum plate.

For the details of each process described in the above items, known conditions can be appropriately adopted. Further, the contents of Japanese Patent Application Laid-Open No. 9-109570 filed by the present applicant and other documents cited in this specification are incorporated herein by reference.

<Photosensitive layer> A conventionally known photosensitive layer is provided on the lithographic printing plate support obtained according to the present invention to obtain a photosensitive lithographic printing plate precursor. The lithographic printing plate thus obtained has excellent performance. The photosensitive substance used in the photosensitive layer is not particularly limited, and those commonly used for photosensitive lithographic printing plate precursors can be used. For example, JP-A-6-135175
Various types as described in Japanese Patent Application Laid-Open Publication No. H10-260, can be used. Before coating the photosensitive layer, the aluminum plate is provided with an organic undercoat layer (intermediate layer) as necessary.
As the organic undercoat layer used for the undercoat layer, a conventionally known organic undercoat layer can be used.
What is described in 35175 gazette can be used. The photosensitive layer may be a negative type or a positive type. Further, a heat-sensitive lithographic printing plate precursor can be obtained by providing a heat-sensitive layer on the lithographic printing plate support obtained by the present invention. The heat-sensitive layer may be negative or positive.

On the surface of the photosensitive layer provided as described above, a mat layer is provided in order to reduce the time for evacuation during contact exposure using a vacuum printing frame and to prevent printing blur. You may be. Specifically, Japanese Patent Application Laid-Open No. 50-125
No. 805, Japanese Patent Publication No. 57-6582, and No. 61-
A method of providing a mat layer as described in Japanese Patent No. 28986, a method of thermally depositing a solid powder as described in Japanese Patent Publication No. 62-62337, and the like.

[0053]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. 1. Preparation of lithographic printing plate support (Example 1) As an aluminum alloy plate, after DC casting,
An aluminum alloy plate 1 (width 1030 m) having the composition shown in Table 2 obtained by performing the soaking treatment and the intermediate annealing
m), the treatment was performed continuously as follows.

(A) Using an alkali etching treatment apparatus of the present invention shown in FIG. 8 on an aluminum plate, a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5.
Alkali etching treatment was performed by spraying at 75% by mass and a liquid temperature of 75 ° C. to dissolve 15 g / m ² of the surface of the aluminum plate. Thereafter, water washing by spraying was performed. In addition,
In the alkaline etching apparatus of the present invention shown in FIG. 8, the masking belt covered the aluminum plate over the entire width of the aluminum plate.

(B) Desmut treatment with a 1% by weight nitric acid aqueous solution (containing 0.5% by weight of aluminum ion) at a liquid temperature of 30 ° C. was carried out by spraying, followed by washing with water by spraying. As the aqueous solution mainly containing nitric acid used for the desmutting, a waste liquid of a step of performing an electrochemical surface-roughening treatment using an alternating current in a nitric acid aqueous solution described later was used.

(C) Electrochemical surface roughening treatment was continuously performed using an AC voltage. The electrolytic solution at this time was a 1% by mass aqueous solution of nitric acid (containing 0.5% by mass of aluminum ions), and the liquid temperature was 50 ° C. In the electrochemical surface-roughening treatment, the time TP until the current value reaches a peak from zero is 1 msec, the duty ratio is 1: 1, and the frequency is 60H.
z, using a trapezoidal rectangular wave alternating current, using a carbon electrode as a counter electrode. Ferrite was used for the auxiliary anode. The current density is 50 A / dm ² at the peak value of the current, and the amount of electricity is 270 C / dm 2 as the total amount of electricity when the aluminum plate is the anode.
^{Was 2} . 5% of the current flowing from the power supply was diverted to the auxiliary anode. Thereafter, water washing by spraying was performed.

(D) Using an alkaline etching apparatus of the present invention shown in FIG. 8 on an aluminum plate, a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5.
Alkali etching treatment was performed by spraying at 75% by mass and a liquid temperature of 75 ° C. to dissolve 1 g / m ² of the surface of the aluminum plate. Thereafter, water washing by spraying was performed. In the alkaline etching apparatus of the present invention shown in FIG. 8, the masking belt covered the aluminum plate over the entire width of the aluminum plate.

(E) A 15 mass% aqueous solution of sulfuric acid at a liquid temperature of 30 ° C. (containing 0.5 mass% of aluminum ions)
Desmutting treatment by spraying was performed, and then washing with water was performed by spraying. As the aqueous solution mainly containing sulfuric acid used for the desmutting, a waste liquid of a step of performing anodizing treatment using a direct current in a sulfuric acid aqueous solution described later was used.

(F) A 15% by mass aqueous solution of sulfuric acid at a liquid temperature of 35 ° C. (containing 0.5% by mass of aluminum ions)
Using a DC voltage, anodizing treatment was performed at a current density of 2 A / dm ^{2 so} that the amount of anodized film was 2.7 g / m ² .
A lithographic printing plate support was obtained.

After each treatment and washing with water, the liquid was drained with a nip roller.

(Example 2) As an aluminum alloy plate,
A planographic printing plate was prepared in the same manner as in Example 1 except that an aluminum alloy plate 2 (width 1030 mm) having a composition shown in Table 2 and obtained by performing a soaking treatment and an intermediate annealing after DC casting was used. A printing plate support was obtained.

(Example 3) As an aluminum alloy plate,
A method similar to that of Example 1 except that an aluminum alloy plate 3 (width 1030 mm) having the composition shown in Table 2 and obtained without performing the soaking treatment or the intermediate annealing after the DC casting was used. Thus, a lithographic printing plate support was obtained.

Example 4 A method similar to that of Example 3 except that the following step (g) was performed instead of the above step (a), and the following step (h) was performed instead of the above step (d). Thus, a lithographic printing plate support was obtained. (G) A caustic soda concentration of 2 was applied to an aluminum plate using the alkaline etching apparatus of the present invention shown in FIG.
Alkali etching treatment by spraying was performed at 6% by mass, an aluminum ion concentration of 6.5% by mass, and a liquid temperature of 75 ° C., thereby dissolving the surface of the aluminum plate at 15 g / m ² . Thereafter, water washing by spraying was performed. In the alkaline etching apparatus of the present invention shown in FIG. 9, the masking roll covered the aluminum plate over the entire width of the aluminum plate. (H) A caustic soda concentration of 2 was applied to an aluminum plate using the alkaline etching apparatus of the present invention shown in FIG.
Alkali etching treatment was performed by spraying at 6% by mass, an aluminum ion concentration of 6.5% by mass, and a liquid temperature of 75 ° C., thereby dissolving the surface of the aluminum plate at 1 g / m ² . Thereafter, water washing by spraying was performed. In the alkaline etching apparatus of the present invention shown in FIG. 9, the masking roll covered the aluminum plate over the entire width of the aluminum plate.

Example 5 A method similar to that of Example 3 except that the following step (i) was performed instead of the above step (a), and the following step (j) was performed instead of the above step (d). Thus, a lithographic printing plate support was obtained. (I) Using an alkali etching treatment apparatus of the present invention shown in FIG. 10, the aluminum plate was subjected to alkali etching treatment by contact at a caustic soda concentration of 26% by mass, an aluminum ion concentration of 6.5% by mass, and a liquid temperature of 75 ° C. ,
15 g / m ² of the surface of the aluminum plate was dissolved. Thereafter, water washing by spraying was performed. In the alkaline etching apparatus of the present invention shown in FIG. 10, the bath was a rectangle having a total length of 15 m and a width of 102 cm. (J) The aluminum plate was subjected to alkali etching treatment by contact at a concentration of 26% by mass of caustic soda, a concentration of 6.5% by mass of aluminum ion and a liquid temperature of 75 ° C. using the alkali etching treatment device of the present invention shown in FIG. ,
1 g / m ² of the surface of the aluminum plate was dissolved. afterwards,
Washing with a spray was performed. In the alkaline etching apparatus of the present invention shown in FIG.
It was a rectangle with a total length of 15 m and a width of 102 cm.

(Example 6) A method similar to that of Example 3 except that the following step (k) was performed instead of the above step (a), and the following step (l) was performed instead of the above step (d). Thus, a lithographic printing plate support was obtained. (K) The aluminum plate is subjected to alkali etching treatment by spraying at a concentration of 26% by mass of caustic soda, a concentration of 6.5% by mass of aluminum ions and a liquid temperature of 75 ° C. using the alkali etching treatment device of the present invention shown in FIG. Then, 15 g / m ² of the surface of the aluminum plate was dissolved. Thereafter, water washing by spraying was performed. Note that, in the alkali etching treatment apparatus of the present invention shown in FIG.
The water spray sprayed water over the entire width of the aluminum plate. (L) The aluminum plate is subjected to alkali etching treatment by spraying at a concentration of 26% by mass of caustic soda, a concentration of 6.5% by mass of aluminum ions and a liquid temperature of 75 ° C. using the alkali etching treatment apparatus of the present invention shown in FIG. Then, 1 g / m ² of the surface of the aluminum plate was dissolved. Thereafter, water washing by spraying was performed. In the alkaline etching treatment apparatus of the present invention shown in FIG. 11, the water spray sprayed water over the entire width of the aluminum plate.

Example 7 As an aluminum alloy plate,
A lithographic printing plate support was obtained in the same manner as in Example 1 except that the aluminum alloy plate 4 (width 1030 mm) having the composition shown in Table 2 and obtained by continuous casting was used.

Comparative Examples 1 to 4 Examples 1 and 2 were repeated except that the following step (m) was performed instead of the above step (a), and the following step (n) was performed instead of the above step (d). In the same manner as in Examples 3, 3 and 7, a lithographic printing plate support was obtained. (M) A caustic soda concentration of 26 was applied to an aluminum plate by using the conventional alkaline etching apparatus shown in FIG.
Mass%, aluminum ion concentration 6.5 mass%, liquid temperature 7
Perform alkali etching treatment by spraying at 5 ° C,
15 g / m ² of the surface of the aluminum plate was dissolved. Thereafter, water washing by spraying was performed. (N) A caustic soda concentration of 26 was applied to an aluminum plate using the conventional alkaline etching apparatus shown in FIG.
Mass%, aluminum ion concentration 6.5 mass%, liquid temperature 7
Perform alkali etching treatment by spraying at 5 ° C,
1 g / m ² of the surface of the aluminum plate was dissolved. afterwards,
Washing with a spray was performed.

[0068]

[Table 2]

2. Measurement of backside etching amount Test piece of 100 mm x 200 mm (same material as aluminum plate used in each example and comparative example)
Attach the gum tape to the two opposing sides of the test piece so as to protrude from the test piece.
The test piece was placed on the back surface of a 030 mm aluminum plate (web) (the test piece was placed so that the 100 mm side was parallel to the longitudinal direction of the web). Next, another gum tape was stuck on the gum tape protruding from the test piece so that the adhesive surface was on the lower side, and the remaining portion protruding was stuck on the back surface of the aluminum plate. In the same manner as in Examples 1 to 7 and Comparative Examples 1 to 4, an alkali etching treatment was performed using the aluminum plate to which the test piece was attached in this manner, and the back surface was etched based on the difference in the mass of the test piece before and after the treatment. The amount was calculated.

3. Evaluation of Backside Appearance The appearance of the backside of the lithographic printing plate support obtained in each of Examples and Comparative Examples was visually evaluated. The appearance was evaluated to the extent that streaks and unevenness had occurred.
○ △, △, △
A ranking of × was given, and a grade of ○ △ or higher was regarded as a pass level.

Table 3 shows the etching amount of the back surface and the results of the evaluation of the appearance of the back surface. According to the method for producing a lithographic printing plate support of the present invention, since the etching amount of the back surface is 1.5 g / m ² or less, the back surface of the lithographic printing plate support can be used no matter what aluminum plate is used. (Examples 1 to 7). On the other hand, the conventional method for producing a lithographic printing plate support uses an aluminum plate obtained without performing soaking treatment and intermediate annealing after DC casting (Comparative Example 3). When an aluminum plate obtained by continuous casting is used (Comparative Example 4), streaks and unevenness occur on the back surface of the lithographic printing plate support. Also,
In Comparative Examples 1 and 2, no problems such as stripes and unevenness occurred, but the liquid fatigue was large and the thickness of the aluminum plate was greatly reduced.

[0072]

[Table 3]

[0073]

According to the method for producing a lithographic printing plate support of the present invention, no problem occurs in the appearance of the back surface, no matter what aluminum plate is used, and the liquid fatigue And the decrease in the thickness of the aluminum plate is suppressed. Further, the alkali etching treatment apparatus of the present invention is suitably used for the method for producing a lithographic printing plate support of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a conventional alkaline etching apparatus.

FIG. 2 is a side view showing a concept of a brush graining process used for a mechanical surface roughening process used in the present invention.

FIG. 3 is a waveform diagram showing an example of a trapezoidal wave used in an electrochemical surface roughening treatment using an alternating current used in the present invention.

FIG. 4 is a side view showing an example of an arrangement of anode and cathode electrolytic treatment cells in a DC surface roughening treatment used in the present invention.

FIG. 5 is a side view showing an example of an electrolytic processing cell structure in which a cathode electrode and an anode electrode are arranged in one tank used in the present invention.

FIG. 6 is a side view showing an example of a radial cell in the AC surface roughening treatment used in the present invention.

FIG. 7 is a side view showing an example in which two radial type cells for AC surface roughening treatment used in the present invention are arranged in series.

FIG. 8 is a schematic sectional view showing an example of the alkali etching treatment apparatus of the present invention.

FIG. 9 is a schematic sectional view showing another example of the alkali etching treatment apparatus of the present invention.

FIG. 10 is a schematic sectional view showing another example of the alkali etching treatment apparatus of the present invention.

FIG. 11 is a schematic sectional view showing another example of the alkali etching treatment apparatus of the present invention.

FIG. 12 is a schematic view of a processing tank for performing desmutting and water washing by spraying.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Aluminum plate 2, 4 Roller brush 3 Polishing slurry liquid 5, 6, 7, 8 Supporting roller 11 Aluminum plate 12 Radial drum roller 13a, 13b Main electrode 14 Electrolytic treatment liquid 15 Electrolyte supply port 16 Slit 17 Electrolyte passage 18 Auxiliary anode 19a, 19b Thyristor 20 AC power supply 28 Cathode 29 DC power supply 30 Anode 31 Pass roll 40, 41 Main electrolytic tank 50, 51 Auxiliary anode tank 60 Processing tank 61 Spray tube 62 Nip roller 100, 110, 120, 130, 140 Alkaline etching treatment Apparatus 101 Roll 102, 111, 121, 141 Spray 103 Between roll and aluminum plate 112 Masking belt 122 Masking roll 131 Bath 142 Rinse spray

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hirokazu Sawada 4,000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Inside Fujisha Shin Film Co., Ltd. In-house F term (reference) 2H025 AB03 DA17 DA18 DA20 2H096 AA06 AA07 CA01 CA03 LA16 2H114 AA04 AA14 AA23 BA01 DA04 EA02 FA01 FA06 GA05

Claims (2)

[Claims] 1. A method for producing a lithographic printing plate support having an alkaline etching step, wherein the backside etching amount is 1.5 g / m ² or less. ^2. An alkali etching apparatus for controlling the amount of etching of the back surface to 1.5 g / m ² or less.