JPH02693B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a photosensitive lithographic printing plate, and more particularly to a method for treating an aluminum plate used as a support for a photosensitive lithographic printing plate. Conventionally, various materials have been used as supports for photosensitive planographic printing plates, but plate-like materials of aluminum and aluminum-based alloys are the most widely used supports in large quantities. be. The aluminum support is usually subjected to a treatment to roughen its surface so that the coating film of the photosensitive layer provided thereon will firmly adhere to it. Specifically, there are chemical, mechanical, or electrochemical means, or a combination thereof, and one of these processes is a mechanical graining process followed by an anodizing process. be. This combined process is a process that has been completed empirically in the past, and when a photosensitive layer is coated on it to form a lithographic printing plate, the adhesive strength between the aluminum support and the photosensitive layer ( ,
It's called "adhesion." ), and the printing plate has good printing durability, so it has been used as an excellent method for many years. However, when a photosensitive layer using an o-quinonediazide compound, which is a so-called positive working photosensitive composition, is coated on an aluminum support by such a process, when the lithographic printing plate is imagewise exposed and developed, it is removed by the development. Film fragments of the photosensitive layer remain in the pores of the anodic oxide film even in areas where they should be removed, destroying the hydrophilic properties of the porous aluminum surface and causing ink to adhere to non-image areas of the printing plate surface. As a result, printed matter often suffers from a problem called "staining." Furthermore, even if the above-mentioned background smudge does not occur, there is a problem in that the colored substances of the photosensitive layer components remain in the pores of the oxide film or are adsorbed to the pore walls and become colored, reducing the contrast of the image after development. Ta. Conventionally, the aluminum plate was anodized as described above, and then the
In some cases, hydrophilic treatment was performed using an alkali silicate as described in US Pat. In some cases, the above-mentioned coloring of non-image areas is prevented, and even if the printed matter is used as a printing plate in a printing machine, "background staining" does not occur on the printed matter, but on the other hand, the printing durability of the printing plate is affected by this hydrophilic property. A new problem arose in that the amount decreased to 40-80% of that without treatment. The inventors of the present invention have made extensive studies to solve the problems encountered in the prior art as described above, and have come up with the following invention that solves all of these problems. That is, the present invention provides a method for producing a photosensitive lithographic printing plate in which a photosensitive layer containing an o-quinonediazide compound is coated after graining and then anodizing an aluminum plate. A method for producing a photosensitive lithographic printing plate, which comprises applying water in the form of fine particles to the surface of the aluminum plates, stacking the aluminum plates and leaving them to stand, and then coating the above-mentioned photosensitive layer. . The present invention will be explained in detail below. The aluminum plate used in the present invention is
It is a plate-shaped body such as a pure aluminum plate whose main component is aluminum or an aluminum alloy containing a small amount of foreign atoms. These foreign atoms include silicon, copper, manganese,
There are magnesium, chromium, zinc, bismuth, nickel, iron, titanium, etc., and the alloy composition is as follows.
The content is at most 10% by weight or less. The preferred aluminum for the present invention is pure aluminum, but since it is difficult to manufacture a completely pure aluminum plate due to scouring technology, the aluminum should contain as few foreign atoms as possible. Furthermore, any aluminum alloy having the above-mentioned content can be said to be a material that can be applied to the present invention. As described above, the composition of the aluminum plate applied to the present invention is not specified, and conventionally known and publicly used materials can be used as appropriate. As already explained, the aluminum plate in the present invention is a plate-shaped body. This plate-shaped body may be sheet-shaped or band-shaped, and the shape of the sheet-shaped body from the top is generally rectangular, but it may have a special shape. The thickness of the aluminum plate is preferably about 0.1 mm to 0.4 mm. The above aluminum plate is subjected to graining treatment. This graining treatment is a technique that has been widely used as a primary surface treatment for aluminum materials. This is usually done by rubbing an abrasive onto the surface of the aluminum plate to be treated while supplying a liquid medium. For rubbing the abrasive, brushes, puffs, bundles of fibers, cloth, etc.
A sponge, a solid surface (sometimes the abrasive itself), a steel ball, etc. is slid or impinged onto the aluminum surface. Another method is to spray a gas or liquid together with a powdered abrasive onto the aluminum surface. Examples of abrasives include diamond, crystal, flint, granite, alundum, silica, diatomaceous earth, which are known as industrial abrasives.
Examples include sand, diamond sand, garnet, talc, pumice, dolomite, magnesium oxide, etc., and those with the desired particle size and processing are used. These grain polishing methods are known methods such as ball polishing, brush polishing, blast polishing, and buff polishing, and any of them can be applied to the present invention. After the graining treatment described above, washing with water or
Alternatively, after washing with water and undergoing chemical treatment, the aluminum plate is anodized. In this anodizing process, an aluminum plate is placed as an anode in various electrolyte solutions and electrolytically oxidized. Examples of the electrolyte include sulfuric acid, hydrochloric acid, nitric acid, oxalic acid, chromic acid, phosphoric acid, benzenesulfonic acid, sulfamic acid, boric acid, ammonium borate, ammonium carbonate, citric acid, tartaric acid, or special mixed acids. The concentration of the electrolyte is appropriately determined depending on the type of electrolyte. The processing conditions for anodic oxidation vary depending on the electrolyte used, so they cannot be specified, but in general, the electrolyte concentration is 1 to 80% by weight, the solution temperature is 5 to 70°C, Current density 0.5-60 ampere/ ^dm2 ,
A voltage of 1 to 100 V and an electrolysis time of 30 seconds to 50 minutes are suitable. More preferable processing conditions are shown in the following table.

[Table] This anodic oxidation treatment has been conventionally carried out in various decomposition processes under various conditions within the above-mentioned range, so those skilled in the art will easily be able to carry out anodization as one of the steps of the present invention. It is. The aluminum plate that has undergone the anodizing treatment is subjected to appropriate treatments such as washing with water, if desired. Water in the form of fine particles is then applied to the aluminum plate that has undergone the anodizing treatment as described above. This particulate water has a particle size of about 0.1 to 50 μm, and is produced by an ultrasonic atomization method, an air jet method, a spray method, or the like. water particle size
If it is smaller than 0.1μm, it will contact the aluminum plate surface,
It becomes difficult to adhere, and the effect of the present invention is hardly produced, and if it is larger than 50 μm, water particles easily combine with each other to form large particles, which may wet the surface of the aluminum plate and cause corrosion. The atmosphere in which this particulate water is applied to the aluminum plate is preferably a temperature of 20 to 40°C and a relative humidity of 80 to 100%, and the application time is preferably about 5 to 180 seconds. After the application of this particulate water and until the aluminum plates are stacked, the aluminum plate should be in contact with the outside air for 0 to 300 seconds, and the outside air temperature should be within the range of 10°C to 50°C. The aluminum plate to which particulate water has been applied is
After being exposed to the outside air as described above, they are stacked,
left alone. This stacking may be done by winding the aluminum plate into a roll when it is in the form of a band, or by stacking the sheets one after another when the aluminum plate is in the form of a sheet. Stacking (including winding into a roll) requires that each leaf and each wound layer be overlapped. Therefore, if the aluminum plate is in the form of a band, it is desirable that the width be the same, and if it is in the form of a sheet, it is desirable that each leaf has the same shape. The stacked aluminum plates are left alone for approximately 24 hours or more. The atmosphere in the place where it is left may be at room temperature and humidity, but some elevation is acceptable. O-
A photosensitive layer containing a quinonediazide compound is applied. The o-quinonediazide compound is a compound having at least one o-quinonediazide group, and its solubility changes upon irradiation with actinic rays. Regarding this o-quinonediazide compound,
“Light−Sensitive” by Jaromir Kosar
Systems：Chemistry and Application of
Nonsilver Halide Photographic Processes”
(John Wiley & Sons, Inc.) pages 339-352, and all of these are compounds that can be applied for the present invention. Particularly suitable are sulfonic acid esters or sulfonamides of o-quinonediazide reacted with various aromatic polyhydroxyl compounds or amines. And the ester of benzoquinone-1,2-diazide sulfonic acid chloride and polyhydroxyphenyl or the naphthoquinone-1,2-diazide sulfonic acid chloride and pyrogal-acetone resin described in Japanese Patent Publication No. 43-28403. esters are most preferred. Other relatively suitable o-quinonediazide compounds include US Pat. No. 3,046,120
There are esters of benzoquinone-1,2-diazide sulfonic acid chloride or naphthoquinone-1,2-diazide sulfonic acid chloride and phenol formaldehyde resin described in the specifications of No. 1 and No. 3188210. Although the o-quinonediazide compound constitutes the photosensitive layer by itself, it is used together with this type of resin using a resin soluble in alkaline water as a binder. Examples of resins soluble in alkaline water include novolac resins having this property, such as phenol formaldehyde resin, cresol formaldehyde resin, pt-butylphenol-formaldehyde resin, phenol-modified xylene resin, and phenol-modified xylene/meditylene resin. It is. Other useful alkaline water-soluble resins include polyhydroxystyrene, copolymers of polyhalogenated hydroxystyrenated (meth)acrylic acid and other vinyl compounds. The amount of the o-quinonediazide compound in the composition comprising the o-quinonediazide compound and the resin soluble in alkaline water is within the range of 10 to 50% by weight, and the ratio is usually about 20 to 40% by weight. be done.
In addition, the composition comprising the o-quinonediazide compound may contain a cyclic acid anhydride, a dye as an image coloring agent, and other desired extenders (fillers) to increase sensitivity.
etc. can be added as appropriate. The coating liquid for forming the photosensitive layer contains the above-mentioned components, for example, 2-methoxyethanol, 2-
Ethoxyethanol, 2-methoxyethyl acetate, 2-ethoxyethyl acetate, dimethylformamide, methanol, ethanol, n-propanol, i-propanol, methylene chloride,
Organic solvents such as esters such as ethylene dichloride, trichloroethane, monochlorobenzene, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, and methyl amyl acetate. Alternatively, it is prepared by dissolving it in a mixed solvent thereof. The amount ratio of solid components in the coating liquid is about 0.1 to about 25% by weight, more preferably about 1 to 15% by weight. The prepared coating solution can be used, for example, as a doctor coat,
The coating is applied onto the aluminum plate treated as described above by various coating means such as roller coating, gravure coating, beat coating, and dip coating. Drying of the coating liquid layer can also be done by applying conventional techniques, such as at room temperature to high temperature, for example 20°C to 150°C.
Dry in an atmosphere at a temperature within the specified range. The photosensitive layer after drying has a weight of about 0.1 to 7 g/ ^m2 ,
A more preferred amount is 0.5-4 g/ ^m2 . The photosensitive lithographic printing plate thus obtained is imagewise exposed to light from a light source containing active light for o-quinonediazide compounds, such as a carbon arc lamp, xenon lamp, mercury lamp, tungsten lamp, metal halide lamp, etc., and is developed to form a lithographic plate. It will be a printed version. The photosensitive lithographic printing plate according to the present invention has high adhesion strength between the support aluminum plate and the photosensitive layer provided thereon, has excellent printing durability, and is said to have no "background stain" on printed matter. It is an extremely useful printing plate due to its excellent performance.
Further, the manufacturing method of the present invention is industrially advantageous because it is simple in terms of equipment and operation, and can be carried out at low cost. Next, the present invention will be specifically explained based on examples. Example 1 A long strip of aluminum with a purity of 99.5% was rubbed with a nylon brush while pouring a pumice stone (400 mesh) water suspension to make the surface grainy, and then thoroughly washed with running water. did. Then, in a 10% by weight aqueous solution of sodium hydroxide (liquid temperature 50°C),
It was etched by dipping for a second, and then washed again with running water. This was introduced into a bath of 1.5% by weight nitric acid aqueous solution.
Electrolytic graining was carried out for 20 seconds under the following conditions: a liquid temperature of 20° C., a positive voltage of 13 volts, a negative voltage of 6 volts, and an alternating current with a duty cycle of 0.3. After that, in order to remove the smut generated on this surface, a 15% by weight sulfuric acid bath solution (liquid temperature
Desmat treatment was carried out by passing the sample through a temperature of 50°C for 60 seconds. Next, add a sulfuric acid electrolyte with a concentration of 250 g/l (solution temperature: 30
) into an anodizing tank containing a current density of
Anodic oxidation was performed under conditions of 20 A/dm ² to form an oxide film with a thickness of 2 μm. This is then output after going through a washing and drying process.
Exposure for approximately 20 minutes to an atmosphere of distilled water (temperature 27℃, relative humidity 95%) that has been atomized by a 1.7Hz ultrasonic oscillator (Sanyo Electric Co., Ltd. ultrasonic humidifier "CFK-400E"), and immediately Winding ivy. 24 in this rolled state
I left it for a while. Thereafter, the aluminum strip was unwound from the wound material and a coating solution having the composition shown below was applied to form a photosensitive layer. Ester compound of naphthoquinone-1,2-diazide-5-sulfonyl chloride and pyrogallol-acetone resin (Note 1) 0.75 parts Cresol novolak resin 2.00 parts Tetrahydrophthalic anhydride 0.15 parts "Oil Blue-#603" (Note 2) ) 0.04 parts Orthoquinone diazide-4-sulfonic acid chloride 0.04 parts Ethylene dichloride 16 parts 2-methoxyethyl acetate 12 parts Note 1: As described in the examples in US Pat. No. 3,635,709. Note 2: Blue dye manufactured by Orient Chemical Co., Ltd. The coating weight of the photosensitive layer after drying was 2.5 g/m ² . The photosensitive lithographic printing plate created in this way is
PS light (product name, exposure equipment manufactured by Fuji Photo Film Co., Ltd., using metal halide lamp (output 2KW))
60 by placing it 1m away from the light source.
After exposure for seconds, use a developer with the following composition (solution temperature: 23℃).
℃). Sodium metasilicate 90 parts JIS No. 3 Sodium silicate 4 parts Water 1000 parts After development, the plate surface was observed with the naked eye to determine the presence or absence of coloring in the non-image area. Furthermore, this printing plate was attached to a "Heidelberg KOR-O" printing machine and printed, and the number of printed sheets and the presence or absence of scumming were examined. Table 1 shows the respective results. In order to clarify the effects of the present invention, a comparative example was prepared in the above example, except that the exposure to the atomized distilled water atmosphere in the above example was not carried out, and the other conditions were the same as in the example. carried out. The results are shown in Table 1 in parallel with those of the Examples.

[Table] From the results shown in Table 1, it was clear that the effects of the present invention were remarkable.

Claims (1)

[Claims] 1. In a method for producing a photosensitive lithographic printing plate in which a photosensitive layer containing an o-quinonediazide compound is coated after graining and then anodizing an aluminum plate, the aluminum plate subjected to the anodizing treatment is 1. A method for producing a photosensitive lithographic printing plate, which comprises applying water in the form of fine particles to the surface, stacking the aluminum plates and leaving them to stand, and then coating the above photosensitive layer.