JPS6345459B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for manufacturing a metal plate for printing plates that has excellent hydrophilicity, water retention, adhesion resistance of ink-philic substances, halftone dot reproducibility, and printing durability. Unexamined Japanese Patent Publication 1987
-This is an improvement on No. 143490. [Conventional technology and its problems] Currently, metal plates for lithographic printing plates using metal materials include Al plates, which can easily obtain a surface shape suitable for flat plates by mechanical or electrochemical methods. is commonly used. However, since Al-based metal plates for lithographic printing plates are expensive, methods have been taken to reduce the thickness of the Al plate, but thinning the Al plate results in inferior mechanical properties, and generally 0.1~ For example, a 0.3 mm thick Al plate is used for newspaper printing, and is further anodized to improve printing durability. Therefore, Al plates with a thickness of 0.3 mm or less can only be used for light printing. In addition, mechanically or electrochemically polishing an Al plate and then subjecting it to hydrophilic treatment is an extremely complicated treatment process and takes a long time.Although there are many patents related to this, it has not yet been simplified. This is also the reason why lithographic printing plates based on Al plates are expensive. [Problems to be Solved by the Invention] As described above, a metal plate for lithographic printing plates that is inexpensive and has excellent characteristics (particularly halftone reproducibility) has not been obtained. [Means to solve the problem] Therefore, we focused on steel plate, which has better mechanical properties than Al plate and is also cheaper.As a result of our investigation, we found that a plate material based on steel plate is inexpensive and has a thickness of 0.3 mm.
It was found that 0.1 mm is sufficient to obtain mechanical strength equivalent to that of an Al plate. Therefore, we considered how to make the steel plate surface equal to or higher than that of Al plate as a metal plate for lithographic printing.
They discovered a completely new method that is superior to Al plates for lithographic printing. The present invention provides a printing plate that has excellent water resistance, maintains this hydrophilicity over a long period of time without deterioration, and has excellent water retention, adhesion to ink-philic substances, halftone dot reproducibility, and printing durability. The present invention provides a method for obtaining a metal plate for use as a material. The gist is that a steel plate with a thickness of 30 to 250 μm, an average surface roughness of 0.1 to 2 μm, and 40 to 110 HSCs/2.5
Either spray with an acidic solution containing ferric ions, or spray with an acidic solution containing ferric ions so that ferrous ions are the main component. The surface was roughened by Fe plating in a solution of 300 ml, and then plated to give corrosion resistance, and then subjected to a well-known new water treatment. This is a method for producing metal plates for printing plates with excellent adhesion, halftone dot reproducibility, and printing durability. The present invention will be explained in detail below. The plate metal plate of the present invention is a steel plate manufactured by a rolling method and has a thickness of 30 to 250 μm. If the thickness of the steel plate exceeds 250 μm, it will be difficult to process the plate material.
It is also uneconomical in terms of material costs. Also, 30μ
If the thickness is less than m, the manufacturing cost is high and uneconomical, and the spray etching in the next step not only roughens the surface but also melts the steel plate, resulting in significantly poor mechanical strength. Next, the surface average roughness Ra (JIS B 0601) 0.1 to have good hydrophilicity, water retention, and halftone dot reproducibility.
In order to obtain 2 μm, 40 to 110 HSCs/2.5 mm, and a surface shape, an acidic solution containing ferric ions is sprayed onto the steel plate, or an acidic solution containing ferric ions is sprayed onto the steel plate. After spraying in a solution mainly composed of ferrous ions,
Apply Fe plating. If the surface roughness Ra is less than 0.1 μm, the surface will be close to smooth, so hydrophilicity and water retention will not be sufficient. If it is more than 2 μm, it will be too rough and the image will bleed during printing, making it difficult to obtain good prints. I can't. If the HSC is less than 40 pieces/2.5mm, the adhesion with the photosensitizer and halftone dot reproducibility will be extremely poor.
If it is 110 pieces/2.5 mm or more, the removal of the photosensitizer during development will be poor. Etching by spray method is
Compared to etching by immersion, it not only roughens the surface in a short time, but also increases the number of irregularities per single area, and changes the surface shape, improving hydrophilicity, water retention, adhesion to photosensitizer, and network. Point reproducibility is improved. In particular, the halftone dots on a positive type PS plate must be made smaller than those on a positive original during the ultraviolet exposure process, and in order to make the halftone dots smaller,
It is better to whiten the surface or increase the number of ridges per single length of the surface. Furthermore, since spraying not only roughens the surface but also removes smudges generated by etching, desmatting treatment such as etching by dipping is no longer necessary. Also,
Compared to electrolytic etching, it is advantageous because it does not require electricity. Etching by spraying may be done on one side or both sides of the plate. The treatment liquid used is an acidic solution consisting of a halogen bath containing ferric ions as a main component, a sulfuric acid bath, a nitric acid bath, a mixed bath of a chloride bath and a sulfuric acid bath, and a sulfamic acid bath. The inclusion of ferric ions has the advantage of roughening the surface in a short period of time, since the ferric ions are oxidizing agents compared to simple inorganic acids. Furthermore, since a solution containing ferric ions is used, only Fe is eluted by etching, making bath management easy. The concentration of ferric ion is
It can be carried out within the range of 10g/~ solubility,
If the amount is less than 10 g/min, the liquid deteriorates significantly due to the consumption of ferric ions, which not only makes continuous processing difficult but also makes the surface shape non-uniform. Moreover, if the solubility is higher than that, insoluble ferric compounds are generated, which tends to clog the spray nozzle and cause trouble. Therefore, the upper limit of the ferric ion concentration is regulated by the pH, temperature, and type of salt of the etching solution. PH is preferably in the range of 0 to 5, particularly preferably in the range of 0 to 3.5. If it is 5 or more, the solubility of ferric ions decreases and the generation of insoluble ferric compounds clogs the spray nozzle, and the surface shape becomes non-uniform. To adjust the pH, if the etching solution is a chloride, use hydrochloric acid, and if the etching solution is a sulfate, use sulfuric acid. The temperature range is preferably from room temperature to the boiling point, particularly preferably from room temperature to 80°C or less. If the bath temperature is high, it is possible to increase the liquid concentration, but the dissolution rate of iron becomes significantly faster than when the surface is made rough, which promotes liquid deterioration and tends to make the surface shape non-uniform. It is preferable to use a nozzle type that allows the spray liquid to be in a mist rather than a liquid state. In the atomized form, the number of irregularities per single area in the surface shape increases, and pits with a diameter of 1 μm or less are generated, which makes printing easier, and water retention and halftone dot reproducibility are particularly improved. To prevent liquid deterioration due to an increase in ferrous ions, add an oxidizing agent such as hydrogen peroxide or electrolytically oxidize. In the case of chlorides, liquid deterioration can be easily prevented by blowing chlorine gas. be. Furthermore, when performing Fe plating after etching, the solution reduced to ferrous ions is
It is possible to replenish the plating. In that case,
The Fe plating solution uses the same salt as the etching solution.
Fe plating thickness of spray etching is 0.1 to 5μ
It has a good range of m and is mainly used to adjust the average surface roughness Ra after etching. Further, the plating solution may be a known one, such as a halogen bath, a sulfuric acid bath, a mixed bath of a chloride bath and a sulfuric acid bath, or a sulfamic acid bath, and one containing the same salt as the etching solution is used. Next, it is preferable to perform a surface treatment because simply roughening the steel plate will result in poor corrosion resistance and the generation of red rust, which is undesirable. Surface treatments include single-layer plating of metals such as Cr, Ni, Sn, Cu, and Zn that have a rust-preventing effect on steel sheets, multi-layer plating that combines two or more of these metals, and these metals. There are plating methods such as alloy plating that include one or more of the following. Such surface treatment not only improves corrosion resistance but also effectively affects the adhesion to the ink-philic substance forming the image area. In particular, in the case of plating, appropriate growth of electrodeposited nuclei is effective in roughening the surface. For this reason, it is better to perform surface treatment under uneven plating conditions than under smooth plating conditions. It is economical to set the lower limit of this plating thickness to a value that guarantees the corrosion resistance of the steel plate. Even if it is a cheap metal like Zn,
There is no need to make expensive metals such as Cr or Ni extremely thick. Furthermore, by performing a known chemical conversion treatment that imparts corrosion resistance after plating, not only can the thickness of the plating be further reduced, but also the adhesion with the photosensitizer is improved. The known chemical conversion treatment is
For example, chromate, dichromate, phosphate,
Treatment is by immersion in solutions containing molybdates, silicates, borates, perborates, aluminates, etc. or by electrolysis. Some metals that have been surface-treated to have the above average surface roughness exhibit hydrophilic properties and can be used as plate materials as they are, but many surface-treated metal plates have insufficient hydrophilic properties. Moreover, since the hydrophilicity deteriorates significantly over time, hydrophilic treatment is performed again.
The hydrophilic treatment may be carried out by commonly used known methods, such as silicate treatment, organic titanium compound treatment, organic phosphoric acid treatment, ferrocyanate treatment, gallic acid treatment, phosphotungstic acid treatment, polyacrylic acid or CMC treatment. Examples include, but are not limited to, organic polymer coating treatments such as organic polymer coating treatments or treatments with inorganic compound sol. [Function] The metal plate for printing plates treated in the above-described steps has excellent hydrophilicity, water retention, adhesion to ink-philic substances, halftone dot reproducibility, and printing durability. [Example] The following is a concrete explanation using an example. Example 1 A steel plate with a thickness of 150 μm was coated at a temperature of 30°C with a concentration of 380 g/
Ferric chloride solution (PH 0.8, diluted 5 times and measured)
Spray nozzle (TYPE-S manufactured by Yashu Kogyo Co., Ltd.)
The surface was roughened to an average surface roughness Ra of 0.9 μm by blowing through the mold for 40 seconds. Using a solution containing 250 g of zinc sulfate and 30 g of ammonium sulfate, the temperature was 45°C and the current density was 20 A/dm ^{2 .}
Zn was plated to a thickness of 0.7 μm under the conditions of
1 g of sulfuric acid (temperature: 40°C) for 6 seconds. Next, alumina sol (product name:
AS-200, manufactured by Nissan Chemical) 20g/and silica sol (product name: Snowtex-0, manufactured by Nissan Chemical) 1
Electrolysis was carried out for 20 seconds at a current density of 0.2 A/dm ² using a steel plate as a cathode in a solution (temperature: 30° C.) containing g/g/g, followed by washing with water and drying. Furthermore, it was immersed for 10 seconds in a solution containing 2 g of phosphoric acid (temperature: 30° C.), washed with water, and then dried to obtain a metal plate for plate material. Example 2 A 50 g/ferric chloride solution (pH 2.1, measured after diluting 5 times) at a temperature of 70°C was passed through a spray nozzle (Model VE, manufactured by Ikeuchi Co., Ltd.) onto a 30 μm thick steel foil.
By spraying for 10 seconds, the average surface roughness Ra can be reduced.
The surface was roughened to 0.2 μm. Add to this Wat bath (nickel sulfate 240g/, nickel chloride 45g/, boric acid)
30g/), temperature 50℃, current density 5A/d
Ni was plated to a thickness of 0.2 μm under conditions of m ² . Next, a sergeant bath (chromic anhydride 250 g/, sulfuric acid 2.5
g/) at a temperature of 45℃ and a current density of 20A/d.
Plating 0.02 μm of Cr under conditions of m ² and using Ti sol 60
g/d, using steel foil as a cathode in a solution containing chromic anhydride 1 g/d, at a temperature of 30°C and a current density of 0.2 A/d.
Electrolysis was performed for 30 seconds under the conditions of ^m2 , washed with water, and dried to obtain a metal plate for plate material. Example 3 A steel plate with a thickness of 250 μm was coated at a temperature of 45°C with a concentration of 200 g/
The surface was roughened to an average surface roughness Ra of 2 μm by spraying a ferric sulfate solution (PH2.7) through a spray nozzle (VP type, manufactured by Ikeuchi Co., Ltd.) for 40 seconds. Add to this a ferrostane bath (80g of stannous sulfate/
, phenolsulfonic acid 80g/, Neugen EN 20g/), Sn was plated to a thickness of 0.07μm at a temperature of 45℃ and a current density of 10A/ ^dm2 .
In a solution containing 30 g of potassium dichromate,
Temperature: 40℃, current density: 5A/d, using steel plate as cathode
Electrolyzed for 5 seconds at ^m2 . After washing with water, it was immersed for 30 seconds in a solution (temperature: 40°C) containing 0.9 g of sodium carboxymethyl cellulose, and after washing with water, it was dried to obtain a metal plate for printing plate. Example 4 A ferric chloride solution (PH 0.5, 5 times diluted and measured) was sprayed onto a 100 μm thick steel plate at a temperature of 20°C using a spray nozzle (TYPE-AS model manufactured by Yashu Kogyo Co., Ltd.).
for 30 seconds, then ferrous chloride
800g/temperature 90℃, current density 20A/
By plating Fe with a thickness of 2 μm under the condition of dm ² ,
The surface was roughened to an average surface roughness Ra of 0.5 μm. to this,
Sargent bath (chromic anhydride 250g/, sulfuric acid
2.5g/), temperature 50℃, current density
0.07μm Cr plating was performed under the condition of 20A/ ^dm2 ,
Alumina sol (product name: AS-200, manufactured by Nissan Chemical) 80
The metal plate for plate material was obtained by immersing the plate in a solution containing g/g/g at a temperature of 40° C. and a processing time of 30 seconds, washing with water, and drying. Example 5 A 200 g/ferric chloride solution (pH 1.1, measured after diluting 5 times) was sprayed onto a 200 μm thick steel plate at a temperature of 40°C using a spray nozzle (TYPE-EM manufactured by Yashu Kogyo Co., Ltd.).
The surface was roughened to an average surface roughness Ra of 15 μm by blowing it through a mold. In addition, stannous chloride
Using a bath containing nickel chloride 50g/, sodium fluoride 20g/, and hydrochloric acid 10g/, at a temperature of 50℃ and a current density of 2.5A/ ^dm2 , Ni
-Sn alloy was plated to a thickness of 1 μm and subjected to a known hydrophilic treatment (gum arabic was applied to a thickness of 0.5 μm and dried) to obtain a metal plate for plate material. Comparative Example 1 A steel plate having a thickness of 200 μm and an average surface roughness Ra of 0.5 μm was treated in the same manner as in Example 1 without being subjected to surface roughening treatment.
Zn plating, chromate treatment and hydrophilic treatment were applied. Comparative Example 2 A steel plate with a thickness of 100 μm was coated with Fe plating to a thickness of 5 μm using the same Fe plating solution as in Example 4 at a temperature of 90°C and a current density of 20 A/ ^dm2 , and the surface average roughness Ra was
The thickness was adjusted to 0.5 μm, and the same Cr plating and hydrophilic treatment as in Example 4 were performed. Comparative Example 3 The same steel plate as in Example 1 was immersed in the same ferric chloride solution as in Example 1 for 40 seconds to roughen the surface to an average surface roughness Ra of 0.5 μm. Furthermore, Example 1
The same Zn plating, chromate treatment and hydrophilic treatment were applied. Comparative Example 4 A commercially available Al-based plate-making material. Comparative Example 1 is an example without surface roughening treatment, Comparative Example 2
1 shows an example in which Fe plating was applied as the surface roughening treatment, and Comparative Example 3 shows an example in which immersion etching was performed as the surface roughening treatment. The following various tests were conducted using the plate metal plate thus obtained. <Surface roughness> Surface roughness was measured using a stylus roughness meter (name: SURF-1A,
Using the High Spot Count (manufactured by Tokyo Seimitsu), extract the measured length of 2.5 mm from the cross-sectional curve and distinguish between peaks and valleys by whether they are located above the average line. The number of peaks) was measured. <Hydrophilicity> Immediately after manufacturing the metal plate for plate material, a positive type photosensitive liquid (product name: Quitswipe on positive type, manufactured by Ueno Chemical) was applied. The weight of the photosensitive liquid applied after drying is
It was 2.0g/ ^m2 . A positive manuscript film was closely attached to the lithographic printing plate material thus obtained, and a 2kw metal halide lamp (New Idol Fin manufactured by Iwasaki Electric Co., Ltd.) was used.
2000) as a light source for 70 seconds from a distance of 1 m, and a developer (DP-3 manufactured by Fuji Photo Film Co., Ltd.)
An image was formed by immersing it in Development conditions are 25℃, 45℃
seconds. Hydrophilicity was determined by dropping water onto the hydrophilic area on the plate thus obtained and measuring the contact angle. contact angle
If it was 20° or less, it was marked ○, if it was 20 to 40°, it was marked △, and if it was 40° or more, it was marked ×. <Half dot reproducibility> For the dot reproducibility, the halftone dots (48.9% halftone dots, 150 lines of positive manuscript) of the plate prepared for hydrophilicity evaluation were magnified 50 times and the halftone dot area was measured. For evaluation, if the difference from the positive original was 5% or more, it was marked ◯, if it was 3 to 5%, it was marked △, and if it was 3% or less, it was marked x. <Printing durability> Printing durability was evaluated by offset printing the plate prepared for hydrophilicity evaluation and printing up to 50,000 sheets. [Effects of the invention] The evaluation results are shown in Table 1.

【table】

[Table] As shown in Table 1, the metal plates for plate materials according to the present invention of Examples 1 to 5 are superior in halftone dot reproducibility and printing durability compared to commercially available Al-based plate making materials.
In addition, halftone dot reproducibility and printing durability were improved by performing surface roughening treatment by spray etching and Fe plating after spray etching. Regarding printing durability, no abnormality was observed even after printing 50,000 sheets for Examples 1 to 4, but Comparative Example 1
The image peeled off after 10,000 copies. In Comparative Examples 2 and 3, some images peeled off after 40,000 sheets, and in Comparative Example 4, after 20,000 sheets.

Claims (1)

[Claims] 1. An acidic solution containing ferric ions as a main component is sprayed onto a steel plate having a thickness of 30 to 250 μm so that the average surface roughness is 0.1 to 2 μm and the number of HSCs is 40 to 110 pieces/2.5 mm. A method for roughening the surface of a metal plate for plate material, which is characterized by spraying the surface by a method of: 2. Spray an acidic solution containing ferric ions as the main component onto a steel plate having a thickness of 30 to 250 μm so that the average surface roughness is 0.1 to 2 μm and the number of HSCs is 40 to 110 pieces/2.5 mm. A method for roughening the surface of a metal plate for printing plates, which comprises applying Fe plating to a thickness of 0.1 to 5 μm using a solution containing ferrous ions as a main component.