JPH0571936B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for preserving a photosensitive printing plate, and particularly to a method for preserving a double-sided photosensitive printing plate without reducing vacuum adhesion. [Prior art] Conventionally, when exposing a photosensitive printing plate to light through an original image, the photosensitive printing plate and the original image are placed between a rubber sheet and a pressure bonding glass in order to completely adhere the original image to the surface of the photosensitive layer of the photosensitive printing plate. A method was used in which they were placed one on top of the other, and a vacuum was created between the rubber sheet and the bonded glass to bring them into close contact. In order to shorten the time required for vacuuming and adhesion, for example, as described in JP-A-51-111102, a photosensitive layer is provided with a minute pattern consisting of a coated area and a non-coated area. A printed version is known. Furthermore, Japanese Patent Application Laid-Open No. 12974/1983 discloses a method of powdering a solid powder and fixing it onto a photosensitive printing plate using heat. Furthermore,
JP-A-57-34558 discloses a method of spraying an aqueous solution in which a resin is dissolved or dispersed onto the surface of a photosensitive layer and drying the solution. However, in photosensitive printing plates provided with such fine pattern layers, solid powder layers, etc. (hereinafter referred to as "matte layers"), the height of the convex portions of the matte layers decreases due to pressure, and As a result, there was a drawback that vacuum adhesion deteriorated. For example, recently, with the mass production of photosensitive printing plates, a photosensitive printing plate with a photosensitive layer on one side and a matte layer on the top layer is wound up into a coil, and then it is processed at high speed. A processing method of cutting and packaging is being implemented. This winding is performed under high tension in order to prevent the coil from slipping (unwinding). Therefore, the closer to the center of the winding coil, the greater pressure is applied to the surface of the photosensitive printing plate, crushing the convex portions of the matte layer, and as a result, the vacuum adhesion deteriorates. In addition, users who use a large amount of photosensitive printing plates may want to perform photosensitive printing without any interleaving paper in order to avoid the hassle of removing interleaving sheets for each sheet to protect the photosensitive layer and perform automatic plate making. We hope to supply a large number of plates. However, if a large number of photosensitive printing plates with a photosensitive layer on one side and a matte layer on the top layer are stacked together without interleaf paper and left for a long time, the weight of the lower plate will increase. Furthermore, since a large amount of pressure is applied to firmly tighten the plate so that it does not move, the convex portion of the mat layer is crushed, resulting in a decrease in vacuum adhesion. The reason why the convex parts of the mat layer are crushed by pressure and the vacuum adhesion deteriorates as a result is that the resin forming the convex parts of the mat layer is soft. It is also thought that the large convex portions, which greatly contribute to vacuum adhesion, are selectively crushed. Therefore, in order to prevent a decrease in vacuum adhesion or variations from plate to plate, the convex parts of the mat layer should be made of a hard material, or the height distribution of the convex parts should be made as narrow as possible, and the pressure should be increased. It can be seen that the influence of pressure can be reduced by distributing it to as many convex parts as possible. The present inventor has already formed a matte layer on the surface of a photosensitive printing plate, and then applies pressure to the matte layer in advance to reduce the height of the convex portions of the matte layer and average it out. We have found a method for preventing the decrease and fluctuation of vacuum adhesion (Japanese Patent Application Laid-Open No. 60-205544). However, with this method, it is necessary to stably produce a matte layer that has sufficient vacuum adhesion even after being crushed under pressure.
When crushing with a metal roll, there is a drawback that if the metal roll is scratched or foreign matter adheres to it, the photosensitive layer will be scratched. By the way, due to the recent demand for resource saving, double-sided photosensitive printing plates in which photosensitive layers are provided on both sides of a support have become popular. Furthermore, such a photosensitive printing plate with a matte layer on the surface of both photosensitive layers has been put into practical use (FPP-
B) is disclosed in JP-A-57-34558 and Example 1 thereof. However, these products are made by forming a matte layer on both sides, then layering interleaf paper and cutting it into sheets without rolling it up, and packaging a small amount (50 sheets or less). There has never been a case where a large amount of paper was stacked without interleaving paper. This is because even though double-sided photosensitive printing plates have become popular, their usage is still small.
This is because high-speed processing and large-volume supply were not required. [Object of the Invention] An object of the present invention is to provide a storage method that can supply double-sided photosensitive printing plates at high speed and in large quantities, with little deterioration or fluctuation in vacuum adhesion. [Structure of the Invention] As mentioned above, the inventor of the present invention has investigated various ways to reduce the influence of pressure by distributing the pressure on the mat layer to as many convex parts as possible, and as a result, the inventor has developed a method of distributing the pressure on the mat layer to as many convex parts as possible and reducing the influence of the pressure. photosensitive printing plate with
Rolling over 1000m or 500m without interleaving paper
The inventors have discovered that even when stacking more than one sheet, the vacuum adhesion does not deteriorate much, and the present invention has been completed. The present invention involves storing a photosensitive printing plate, which has a photosensitive layer and a matte layer on both sides of a long support, by winding it for 1000 meters or more, or stacking 500 sheets or more without stacking interleaf sheets after cutting. This is a method for preserving photosensitive printing plates, which is characterized by: Hereinafter, the method for manufacturing the photosensitive printing plate used in the present invention will be explained in detail. The photosensitive printing plate material used in the present invention includes:
Any support may be used as long as the support is made of a metal such as aluminum, iron, or zinc, and if necessary, both surfaces are subjected to surface treatment and then photosensitive layers for flat plates or convex plates are provided on both sides. Such photosensitive printing plate materials are described in detail in many literatures and patent specifications, and photosensitive planographic printing plates include pre-sensitized plates.
Plate (abbreviated as PS version) is commercially available. Various supports for such photosensitive lithographic printing plates are known, and details thereof are described in British Patent Publication No. 2030309A. It takes advantage of the fact that the solubility or swelling property of these photosensitive layers in a developer changes before and after exposure, and there are various combinations of photosensitive material and developer. For example, photosensitive materials include diazo resins, o-quinone diazide compounds, photosensitive azide compounds, photopolymerizable compounds, and photosensitive resins. These details are also explained in detail in the above-mentioned publication. The thickness of the photosensitive layer is generally 0.17 dry weight per side.
g/m ² , preferably 0.5 to 3 g/m ² . Examples of developing solutions suitable for photosensitive layers made of these photosensitive materials include organic solvents containing various additives, aqueous alkaline solutions, and aqueous surfactant solutions. The photosensitive printing plate used in the present invention has matte layers formed on both sides. The matte layer forming method applicable to the present invention includes a method of making the photosensitive layer uneven (a method of making the photosensitive layer uneven during coating, a method of internally adding a matting agent, a method of making the photosensitive layer uneven when drying),
There are various methods such as making the top layer that does not contain a photosensitive material uneven (a resin layer containing a matting agent, a matte layer consisting of a coated area and a non-coated area), but these methods have a negative effect on vacuum adhesion and other performances. To a lesser extent, a method of forming a matte layer consisting of coated and non-coated parts is advantageously used. Particularly preferred is one in which the applied portion is removed during development. Copolymers containing the following monomer units (a), (b), and (c) are particularly preferred as resins used in this method, from the viewpoint of strong adhesion to the photosensitive layer and hardness. Are better. (a) at least one monomer unit selected from the group consisting of alkyl acrylates whose alkyl residues have 2 to 10 carbon atoms and alkyl methacrylates whose alkyl residues have 4 to 10 carbon atoms; . (b) At least one monomer unit selected from the group consisting of styrenes, acrylonitriles, methyl methacrylate and ethyl methacrylate. (c) Acrylic acid, methacrylic acid, maleic acid, itaconic acid, monomers having sulfonic acid groups, such as p-styrene sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, ethylene sulfonic acid, alkali metal salts thereof, and At least one monomer unit selected from the group consisting of ammonium salts. The monomer unit (a) is a component that imparts adhesion to the surface of the photosensitive layer, and specific examples include ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n- Amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-decyl acrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate,
Included are 2-ethylhexyl methacrylate, n-octyl methacrylate, n-decyl methacrylate, and the like. The monomer unit (b) is a component that imparts resistance to pressure, and specific examples thereof include styrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, 2,
4,5-trimethylstyrene, 2,4,6-trimethylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, 3,5-diethylstyrene, 2,4,5-triethylstyrene, p-n -butylstyrene, m-sec-butylstyrene, m-tert-butylstyrene, p-hexylstyrene, p-n-heptylstyrene, p-
2-Ethylhexylstyrene, o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, 2,3-dichlorostyrene, 2,4-dichlorostyrene, 2 , 5-dichlorostyrene, 2,6-dichlorostyrene, 3,
4-dichlorostyrene, 3,5-dichlorostyrene, 2,3,4,5,6-pentachlorostyrene, m-trifluoromethylstyrene, o-cyanostyrene, m-cyanostyrene, m-nitrostyrene, p- Nitrostyrene, p-dimethylaminostyrene, acrylonitrile, α-chloroacrylonitrile, α-bromoacrylonitrile, α
-trifluoromethylacrylonitrile, α-trifluoromethylcarboxyacrylonitrile,
Includes methyl methacrylate, ethyl methacrylate, etc. The above monomer unit (c) is a component that improves solubility in a developer, and specific examples thereof include acrylic acid, sodium acrylate, potassium acrylate, ammonium acrylate, methacrylic acid,
Sodium methacrylate, potassium methacrylate, ammonium methacrylate, maleic acid, sodium maleate, potassium maleate, ammonium maleate, itaconic acid, sodium itaconate, potassium itaconate, ammonium itaconate and the aforementioned sulfonic acid-containing monomers and their Contains salt. In such copolymers, the monomer units
The amounts of (a), (b) and (c) are 10-70% by weight and 20% by weight, respectively.
-80% by weight and ranges from 6 to 50% by weight are preferred. As the amount of monomer unit (a) decreases below 10% by weight, the adhesion of the copolymer to the surface of the photosensitive layer decreases, while as the amount exceeds 70% by weight, the pressure resistance of the copolymer decreases. Sexuality decreases. Also,
As the amount of monomer unit (b) becomes less than 20% by weight, the hardness of the copolymer decreases and the pressure resistance decreases, while as the amount becomes more than 80% by weight, the copolymer's hardness decreases. The solubility in the developer decreases, and the adhesion to the photosensitive layer also decreases. Furthermore, as the amount of the monomer unit (c) becomes less than 6% by weight, the solubility of the copolymer in a developer deteriorates, while as the amount becomes more than 50% by weight, the copolymer becomes brittle, and the photosensitive layer becomes weaker. The adhesion force to the surface also decreases. Therefore, particularly preferred monomer units
The amounts of (a), (b) and (c) are 15 to 50% by weight, respectively;
40-70% by weight and 10-25% by weight. The above copolymer is produced by solution polymerizing in an organic solvent, evaporating to dryness, and turning it into a fine powder in a pulverizer.
A part of the acrylic acid- or methacrylic acid-, maleic acid-, itaconic acid- and sulfonic acid-containing monomer (c) can be obtained as a sodium salt, potassium salt, or ammonium salt as an aqueous solution of the copolymer. Alternatively, in the same manner as the usual latex synthesis method, raw monomers may be emulsified in water with a surfactant and then emulsion polymerized using a polymerization initiator such as potassium persulfate to obtain an aqueous dispersion. . The copolymer may also contain fillers. Examples of the filler include silicon dioxide, zinc oxide, titanium oxide, zirconium oxide, glass particles, alumina, and polymer particles (eg, particles of polymethyl methacrylate, polystyrene, phenolic resin, etc.). Two or more of these can be used in combination. Methods for coating these resins to form a matte layer include a method in which fine powder of the resin is fixed to the photosensitive layer using heat or a solvent (Japanese Patent Application Laid-Open No. 12974/1983), and a method in which the resin is dissolved or dispersed. A method of spraying and drying an aqueous liquid
34558), but from the viewpoint of safety, manufacturing stability, cost, etc., the matting methods described in JP-A-57-34558 (air spray method, airless spray method, electrostatic air spray method) , electrostatic atomization, electrostatic coating method, etc.) are preferred, and electrostatic atomization and electrostatic coating method, which has a high adhesion rate, is particularly preferred. In the present invention, the height of the mat of the photosensitive printing plate used should be high in order to improve vacuum adhesion, but if it is too high, the distance between the photosensitive layer and the film will be too wide, resulting in poor tone reproducibility. The image quality decreases and blurring occurs. For this reason, it is particularly preferable that the height is in the range of 1 to 15 μm. In order to increase the height of the convex portion, it is better to increase the particle size of the fine powder when using the method disclosed in JP-A-55-12974, and by increasing the particle size of the fine powder when using the method disclosed in JP-A-57-34558. It is preferable to increase the concentration, increase the size of the matte liquid fine particles, raise the temperature and lower the humidity during the adhesion of the fine particles, reduce the amount of post-humidification, etc., and it is particularly good to increase the liquid concentration. Although the size (width) and amount (number) of the convex portions have a smaller influence on the vacuum adhesion time than the influence of the height of the convex portions, they have a greater influence on their adhesion strength and pressure resistance. Therefore, the size (width) of the convex portion is 5 to 200 μm, and the amount (number) is 1 to 1000 μm.
A suitable number is 5 to 500 pieces/mm ² , preferably 5 to 500 pieces/mm ² .
If it is lower than this range, the adhesion strength and pressure resistance of the convex portions will be low, and if it is higher than this range, it will have an adverse effect on the developability, tone reproducibility, etc. of the photosensitive printing plate. The matte layers provided in this manner may be the same on the front and back surfaces, or may be different. In this way, a photosensitive lithographic printing plate with a matte layer formed on both sides is wound up into a roll of 1000 m or more and then cut, or after being rolled or cut into a sheet without being wound up, it is cut into a sheet with interleaf paper. Stacks and supplies more than 500 sheets without stacking them. When winding into a roll, it is best to use a high tension to prevent the coil from slipping (unwinding). As for the winding method, conventionally known methods can be used; for example, the tension varies depending on the width of the lithographic printing plate and the coil length, etc.
Generally, the initial winding tension is about 100 to 1000 kg,
It is preferable to gradually lower the tension as it is wound up so that the final tension is about 1/4 to 3/4 of the initial tension. Once wound, the coil is cut into sheets while being fed out at high speed. Conventionally, when a photosensitive printing plate with a photosensitive layer and matte layer on one side is wound for more than 1000 m, the matte on the front side is crushed by the metal surface on the back side, and the height of the matte is low, especially in the center of the coil. I'm getting old. On the other hand, when a photosensitive printing plate with a photosensitive layer and a matte layer on both sides is rolled up for more than 1000 m, the height of the matte decreases because the matte on the front and back sides mutually disperse pressure. This reduces the decrease in vacuum adhesion. In addition, it is possible to cut plates into sheets in large quantities, especially without overlapping them with interleaf paper.
To prevent plates that weigh more than 500 sheets from shifting during transportation, they can be supplied with strong tension, especially 10 to 1000 kg. In this case as well, in the case of a plate coated on one side, the mat layer is crushed by the back metal surface under high pressure, whereas in the case of a plate coated on both sides, the height of the mat is less reduced. [Effect of the invention] When a photosensitive lithographic printing plate with a photosensitive layer and a matte layer provided on both sides is wound onto a roll, there is little difference in vacuum adhesion between the center and outer parts, ensuring good vacuum adhesion. can do. Furthermore, even if a large amount of interleaf paper is stacked after being cut into sheets, the vacuum adhesion is less likely to deteriorate, and good vacuum adhesion can be maintained. [Examples] Examples of the present invention will be specifically shown below, but the present invention is not limited thereto. All "%" in the following examples are weight %. Example 1 and Comparative Example a 0.24 mm thick aluminum plate width 1003 mm, length
4000 m was continuously grained on both sides or on one side using a nylon brush and 400 mesh of pumice stone-water suspension, and thoroughly washed with water. This board, 45
Etching is performed by immersing in 25% sodium hydroxide aqueous solution at ℃ for 9 seconds, washing with water, and then dipping in 20% nitric acid for 20
Dipped for a second and washed with water. The amount of etching on the grained surface at this time was approximately 3 g/m ² . Next, this plate was coated with a DC anodic oxide film of 2 g/m ² at a current density of 15 A/dm ² using 7% nitric acid as an electrolyte, and then washed with water and dried. This supporting pair was combined with 1 part by weight of naphthoquinone-1,2-diazide-5-sulfonic acid ester of polyhydroxyphenyl obtained by polycondensation of acetone and pyrogallol as described in Japanese Patent Publication No. 43-28403, and a novolak type cresol. A photosensitive solution was prepared by dissolving 2 parts by weight of formaldehyde resin in 20 parts by weight of 2-methoxyethyl acetate and 10 parts by weight of methyl ethyl ketone, and the solution was coated on both sides or one side of the support and dried (coating amount after drying was 2.5 parts by weight).
g/m ² ), as described below, spray and adhere the resin liquid for forming a pine layer to form a pine layer to prepare a photosensitive planographic printing plate, then set the initial tension to 400 kg and roll it up for 4000 m. The film was wound up while continuously reducing the tension so that the tension was 200 kg, and then cut and packaged at high speed into 1003 mm x 800 mm to create a double-sided product sample 1 and a single-sided product comparison sample a. Spray is methyl methacrylate/ethyl acrylate/
Using a 12% aqueous solution of acrylic acid (preparation weight ratio 65:20:15) copolymer with a part of sodium salt, the atomization head rotation speed of the rotary atomizing electrostatic coating machine was
25,000 rpm, resin liquid feeding rate is 40 ml/min, voltage applied to the atomizing head is -90 kV, ambient temperature during application is 25
℃, relative humidity is 50%, about 2.5 seconds after application,
Steam was blown onto the coated surface to moisten it, and then, 3 seconds after wetting, warm air at a temperature of 60° C. and humidity of 10% was blown for 5 seconds to dry it. The height of the pine is approximately 6μm,
The size was 30 μm and the number was 150 pieces/mm ² . For each sample, near the winding core, near the middle (2000 m), near the outside of the winding (4000 m), and for comparison samples cut without winding, film original plates (550 mm x 650 mm) were superimposed using a vacuum contact printer. The vacuum adhesion time was measured when the vacuum adhesion was applied. These results are shown in Table 1.

[Table] Comparison example a of single-sided photosensitive lithographic printing plate according to conventional technology
In the case of no winding, the vacuum adhesion time was 20 seconds, the winding outside (25 seconds), the middle (37 seconds)
(seconds), the vacuum adhesion at the winding core (52 seconds) was greatly reduced, and the difference between the outside and the winding core was also large at 27 seconds. On the other hand, in Example 1 of the double-sided photosensitive lithographic printing plate according to the present invention, when the vacuum adhesion time was 20 seconds, the same as for the single-sided product without winding, the outer side (22, 23 seconds), the middle (26 seconds) , 26 seconds), winding core (31,
32 seconds), the decrease in vacuum adhesion is small, and the outer
The difference in the winding core portion is also 9 seconds, which is practically no problem. This is because, through electron microscope observation of the winding core, in Comparative Example A, the high convex part of the pine was pushed in and the height was considerably reduced to about 3 μm.
In Example 1, the decrease in height was small, about 4.5 μm. After placing Example 1 in close contact with the original film, it was exposed to light from a distance of 70 cm using a 30 ampere metal halide lamp, and then DP-4 (product name: Fuji Photo Film)
After developing for 60 seconds at 25° C. with an 8-fold dilution of developer solution manufactured by Co., Ltd., printing was carried out and the tone reproducibility and various performances as a lithographic printing plate were examined and good results were obtained. Example 2 and Comparative Example b In Example 1 and Comparative Example a, 2000 samples were cut without being rolled up and stacked on top of a wooden board and cardboard without overlapping paper, and the plates were made by applying the cardboard and wooden board. Six steel bands were tightened with a tension of 200 kg to prevent it from slipping. After leaving it in this state for one month, we investigated the vacuum adhesion time of the five samples placed at the bottom, and found that Comparative Example B
(single-sided product) took an average of 32 seconds, which was 12 seconds lower than the sample that was not stacked, whereas Example 2 (double-sided product) took 24 seconds for both the front and back sides, a decrease of 4 seconds. . Example 3 and Comparative Example c In Examples 1 and 2, heat-cured phenol resin powder (average particle size 10 μm, resol type cresol-formaldehyde resin pulverized with a diet mill after heating) was used in the coating solution (Japanese Patent Publication No. 1983-
No. 26655, described in Example 2)
After adding 0.03 parts by weight and dispersing, it was coated on both sides of the support and dried to provide matte layers containing the matting agent in the photosensitive layer on both sides. This photosensitive lithographic printing plate was processed in the same manner as in Examples 1 and 2, and then its vacuum adhesion was examined. The results are shown in Table 2. (Example 3 is a double-sided product, Comparative Example c is a single-sided product)

[Table] It can be seen that compared to Comparative Example c, Example 3 maintains good vacuum adhesion with less decrease in vacuum adhesion even in winding processing and stacking processing without interleaving paper. Example 4 and Comparative Example d A styrene-acrylic acid-butyl acrylate (ratio 45:30:20) copolymer was pulverized using a jet pulverizer at supersonic speed, and then classified using a classifier to obtain a unidirectional diameter. Heat-fusible fine powders each having a size of 0.5 to 40 μm were obtained. These heat-fusible fine powders were powdered (approximately 170 pieces/mm ² ) on one side of the photosensitive lithographic printing plate before being sprayed as shown in Example 1 using a spray gun, and then heated in air at 150°C. After being exposed to a bath for 10 seconds and fixed, the back side of Example 4 was coated with Example 1.
After providing the matte layer shown in Examples 1 and 2
After performing the same processing as above, the vacuum adhesion was examined. The results are shown in Table 3. (Example 4 is a double-sided product, Comparative Example d is a single-sided product)

[Table] It can be seen that the surface of Example 4 maintains good vacuum adhesion with less decrease in vacuum adhesion even during winding processing and stacking processing without interleaving paper compared to Comparative Example d. . It was also found that it is effective to use different types of pine layers on the front and back sides. (The back side of Example 4 is compared with Comparative Examples a and b) Example 5 and Comparative Example e After providing the anodic oxide film of Example 1, the washed and dried support was placed in tribasic sodium phosphate at 70°C. After being immersed in an aqueous solution (5%) for 1 minute, it was washed with water and dried.
A photosensitive solution having the following composition was applied to this support and dried. 2-Hydroxyethyl methacrylate copolymer () (Note) ...0.87g 2-methoxy-4-hydroxy-5-benzoylbenzenesulfonate of condensate of p-diazodiphenylamine and paraformaldehyde
...0.1g "Oil Blue #603" ...0.03g Methanol ...6g 2-methoxyethanol ...6g Note 1: As described in Example 1 of U.S. Patent No. 4123276. The amount of coating is for both the front and back sides. It was applied at a concentration of 2 g/m ² . On this photosensitive plate, an aqueous solution (solid content concentration 14%) of a copolymer having the following composition was applied and dried in the same manner as in Example 1. Methyl methacrylate 50% Ethyl acrylate 30% 2-acrylamide-2-methylpropanesulfonic acid 20% Copolymer matte coating amount is approximately 0.1 g/m ² , approximately 150%
pieces/ ^mm2 , height of pine approximately 5μm, size 20-40μm
It was hot. When this photosensitive printing plate was rolled up and stored in a stack in the same manner as in Examples 1 and 2, it showed better vacuum adhesion than Comparative Example e in which a photosensitive layer and a matte layer were provided on only one side.

[Table] After exposing this photosensitive printing plate through a film,
Plate-making printing was performed in the same manner as in Example 1 described in US Pat. No. 4,123,276, and good printing results were obtained.

Claims (1)

[Claims] 1. A photosensitive printing plate with a photosensitive layer and a matte layer on both sides of a long support may be rolled up and stored for 1000 meters or more, or stacked and stored for 500 sheets or more without overlapping paper after cutting. Characteristic method of preserving photosensitive printing plates.