JPS6330997B2 - - Google Patents

Description

[Detailed description of the invention]

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, and is disclosed in JP-A-57
This is an improvement on No. 143490 (Published on September 4, 1981, Manufacture of metal plates for printing plates). A lithographic printing plate is used for printing by providing a hydrophilic non-image area and an ink-philic image area on the same plane. It is very important that the non-image area has water-compatible properties, that is, hydrophilicity, and metal plates for lithographic printing plates generally take on this role. In addition, the PS plate, which is a type of lithographic printing plate, is coated with a photosensitive resin in advance, and by immersing it in a strong alkaline developer after exposure, the photosensitive resin in the non-image area is eluted, while the image area is coated with a photosensitive resin. The photosensitive resin remains and creates an image. For this reason, the surface of the metal plate for planographic printing plates has a contradictory structure in which the adhesion with the photosensitive resin in the image area does not deteriorate during development, and the photosensitive resin in the non-image area does not remain and exhibits hydrophilicity. It is necessary to have the characteristics to Another feature of the non-image area is that it is required to have excellent water retention. Therefore, Al plates with a thickness of 0.1 to 0.3 mm are generally used as metal plates for lithographic printing plates using conventional metal materials. In order to improve the adhesion with the photosensitive resin mentioned above or water retention, the surface of the Al plate is subjected to graining or anodic oxidation treatment. However, since aluminum is expensive, metal plates for lithographic printing plates based on Al are made thinner, but thinner Al plates have inferior mechanical properties and are generally not used. A thickness of 0.1 to 0.3 mm is required, and for example, a thickness of 0.3 mm is used for newspaper printing. Therefore, if the thickness is less than 0.3 mm, it can only be used for light printing. In addition, by mechanically or electrochemically polishing the Al plate,
Next, hydrophilic treatment is an extremely complicated treatment process, and although there are many patents related to this process, it has not yet been simplified, which is also the reason why lithographic printing plates based on Al plates are expensive. . Therefore, we focused on a steel plate that has better mechanical properties than Al plate and is also cheaper, and as a result, we found that
It was found that the plate material based on steel plate is inexpensive and can have a thickness of 0.1 mm in order to obtain the same mechanical strength as a 0.3 mm thick Al plate. Therefore, we investigated how to make the surface of the steel plate as a metal plate for lithographic printing plates equal to or better than that of an Al plate, and found a completely new method that is superior to that of an Al plate for lithographic printing. The present invention provides a plate material that has excellent hydrophilicity, maintains this hydrophilicity over a long period of time without deterioration, has excellent adhesion to ink-philic substances, and has excellent halftone dot reproducibility and printing durability. The object of the present invention is to provide a method for obtaining a metal plate for use in manufacturing. The gist is that a steel plate with a thickness of 30 to 250 μm is coated with Fe or
The surface is hardened with Fe as the main component, roughened by chemical etching or mechanical polishing, and further surface treated to provide corrosion resistance, then treated with an inorganic compound sol, and further contains phosphoric acid or phosphate. Inexpensive, hydrophilic, water-retentive, bath-treated
This is a method for manufacturing a metal plate for printing plates that has excellent adhesion resistance of ink-philic substances, halftone dot reproducibility, and printing durability. The present invention will be explained in detail below. The metal plate used in 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. Next, by tightening with Fe or Fe as the main component, chemical etching or mechanical polishing, the average surface roughness with good hydrophilicity is achieved.
A product having an Ra (JIS B 0601) of 0.1 to 2 μm can be obtained. If it is less than 0.1 μm, the surface will be nearly smooth, resulting in insufficient hydrophilicity and water retention. If it is more than 2 μm, it will be too rough and the image will bleed during printing, making it impossible to obtain good printed matter. Next, it is preferable to perform a surface treatment, since 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. Particularly in the case of plating, the 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. Aside from cheap metals like Zn, Cr or Ni
There is no need to make expensive metals like this unnecessarily thick. Some of the metals that have been surface-treated with the aforementioned surface roughness exhibit hydrophilic properties and can be used as plate materials as they are, but many of the surface-treated metal plates have insufficient hydrophilic properties. Moreover, since the hydrophilicity deteriorates significantly over time, hydrophilic treatment is performed again. Hydrophilic treatment is as shown in JP-A-57-143490,
Immersion or cathodic treatment in a solution whose main component is a sol of a metal compound consisting of a metal oxide or hydrated oxide. Sol is 0.01~10mg/ as metal
After dm ² deposition, it is necessary to perform immersion or cathodic treatment in a solution containing phosphoric acid or a water-soluble phosphate to improve hydrophilicity and adhesion to the photosensitizer. Although the hydrophilicity and adhesion to the photosensitizer are good even when treated in a solution containing a sol, further improvement may be desired depending on the type of photosensitizer. In that case, these properties can be improved by further performing immersion or cathodic treatment in a solution containing phosphoric acid or a water-soluble phosphate. This is because a phosphorus compound is attached or precipitated to improve the adhesion with the photosensitive agent, especially the adhesion after development and the hydrophilicity of the hydrophilic portion after development. Phosphoric acid or water-soluble phosphate is used as the treatment liquid, and the phosphoric acid is orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid, hypophosphorous acid, hypophosphoric acid, trimetaphosphoric acid or tetrametaphosphoric acid. Water-soluble phosphates include sodium, potassium, ammonium and aluminum salts of these acids. Moreover, organic compound products of these can also be applied. Examples include water-soluble alkyl phosphates such as triethyl phosphate and trimethyl phosphate. It is sufficient to contain one or more of these, and the preferred treatment method is immersion or cathode treatment. Particularly in cathodic treatment, the treatment time can be shortened. The concentration is limited by adjusting the pH of the treatment solution to be in the range of 0.5 to 7.0 and by not forming a precipitate. If the pH is less than 0.5, not only the gelled sol will be eluted and the processing solution will become unstable, but also the adhesion to the photosensitizer or hydrophilicity will not be improved. On the other hand, if the pH is 7.0 or higher, the adhesion efficiency of phosphorus decreases, and the adhesion to the photosensitizer and hydrophilicity are not improved. Temperature and treatment time are limited by the amount of phosphorus deposited. An effect is recognized when the amount of phosphorus attached is 0.05 to 10 mg/dm ² , but it is not effective when it is less than 0.05 mg/dm ² .
When it exceeds mg/dm ² , economical efficiency and workability decrease. This will be explained in detail in Examples below. Example 1 A rolled steel foil with a thickness of 100 μm was coated on one side in a chloride bath mainly containing Fe ions at a temperature of 98°C and a current density.
Fe plating of 8 μm was applied at 10 A/dm ² to give an average surface roughness of 0.9 μm. Next, using a sergeant bath (chromic anhydride 250g/, sulfuric acid 2.5g/), the thickness was 0.1μ at a temperature of 45℃ and a current density of 40A/ ^dm2 .
Cr plating of 50 nm was performed, electrolyzed for 30 seconds at a current density of 0.1 A/dm ² in a solution containing 20 g of alumina sol (AS-200, manufactured by Nissan Chemical) with an average particle size of 50 nm, and washed with water. It was then dried. Furthermore, phosphoric acid 2
In a solution (PH2.4) containing g/
It was immersed for a treatment time of 30 seconds, washed with water, and dried to obtain a metal plate for plate material. The amount of phosphorus attached is 0.4 mg/dm ²
It was hot. Example 2 A steel plate with a thickness of 250 μm was etched by immersing it in a ferric chloride solution at 47° Be and a temperature of 45° C., and the surface was roughened to an average surface roughness of 2 μm. Using a sulfate bath, the temperature was 50℃ and the current density was 5A/ ^dm2 .
Zn was plated with a thickness of 2 μm and immersed in a solution containing 20 g of alumina sol and 0.5 g of silica sol with an average particle size of 50 nm at a temperature of 40°C and a treatment time of 30 seconds.
Dry. Then, it was placed in a solution (PH4.9) containing 60g of sodium phosphate and 40g of phosphoric acid at a temperature of 25%.
Cathode treatment was carried out under the conditions of 2 seconds of treatment time, washed with water, and dried to obtain a metal plate for plate material. The amount of phosphorus attached is 0.1
mg/ ^dm2 . Example 3 400 g of ferrous sulfate was applied to one side of a 30 μm thick steel foil.
, using a plating bath containing 100 g of ammonium sulfate and 50 g of nickel sulfate at a temperature of 70°C and a current density of 5 A/d.
Fe-Ni plating was performed to a thickness of 3 μm under conditions of m ² and the surface was roughened to an average surface roughness of 0.3 μm. Next, tin chloride 250g/, nickel chloride 50g/
, using a solution containing 20 g of sodium fluoride/10 g of hydrochloric acid, at a temperature of 50°C and a current density of 2.5 A/.
A Ni-Sn alloy was plated with a thickness of 1 μm under conditions of dm ² , and a current density of 0.2 A/dm ² was applied using a solution containing 60 g of Ti sol and 1 g of chromic anhydride, using a steel foil as a cathode.
Second electrolysis was performed, washed with water, and then dried. Next, it was immersed in a solution (PH3.0) containing 20 g of trimethyl phosphate and 1 g of phosphoric acid at a temperature of 55°C and a treatment time of 60 seconds, washed with water, and dried to obtain a metal plate for plate material. I got it. The amount of phosphorus deposited was 1.5 mg/dm ² . Example 4 A steel plate with a thickness of 150 μm was coated with grain size (JIS
R6001) Mechanical polishing is performed by spraying an aqueous solution containing #200 alumina (product name: ABRAX, manufactured by Nippon Abrasive Industry Co., Ltd.), and the average surface roughness is reduced to 0.7μ.
The surface was roughened to m. This is followed by a Watts bath (nickel sulfate).
240g/, nickel chloride 45g/, boric acid 30
g/), temperature 50℃, current density 5A/dm ²
Ni was plated to a thickness of 0.2 μm under the conditions of
at a temperature of 45℃ and a current density of 40A/ ^dm2 .
After plating 0.2 μm of Cr, 50 g of alumina sol/
, electrolytic treatment was carried out for 20 seconds at a current density of 1 A/dm ² using a steel plate as a cathode in a solution containing 1 g of Zr sol, followed by washing with water and drying. In a solution (PH2.1) containing 5 g of pyrophosphoric acid, at a temperature of 35°C for a processing time.
It was immersed for 20 seconds, washed with water, and then dried to obtain a metal plate for plate material. The amount of phosphorus deposited was 1.0 mg/dm ² . Comparative Example 1 Using the same steel foil as in Example 1, the same Fe plating and Cr plating as in Example 1 were applied, and the same phosphoric acid treatment as in Example 1 was performed without the sol treatment. Comparative Example 2 Using the same steel foil as in Example 1, the same Fe plating, Cr plating, and sol treatment as in Example 1 were performed,
No phosphoric acid treatment was applied. Comparative Example 3 Commercially available Al-based plate making material. To evaluate the adhesion resistance of ink-philic substances,
Apply a positive type photosensitive liquid (manufactured by Tokyo Ohka Kogyo),
After drying and applying a rough pattern, it was immersed in a developer (Fuji Photo Film DP-3: PH13.0) for 75 minutes to check initial adhesion and alkali resistance.
Each was evaluated by a peel test using an adhesive tape.
Mark ○ for no peeling, mark △ for partial peeling, × mark for complete peeling.
It was marked as a mark. Hydrophilicity is determined immediately after the production of the metal plate for printing plates, by applying a positive type photosensitive liquid (manufactured by Tokyo Ohka Kogyo Co., Ltd.), and exposing it to ultraviolet rays after drying.
It was examined after removing the photosensitizer using DP-3). The evaluation was performed by measuring the contact angle when water was dropped onto the plate. If the contact angle was 20° or less, it was marked with ○, if it was 20 to 40°, it was marked with △, and if it was 40° or more, it was marked with ×. The evaluation results are shown in Table 1. As shown in Table 1, the metal plates for plate materials according to the present invention in Examples 1 to 4 have excellent hydrophilicity and adhesion to photosensitizers, and are particularly superior to commercially available aluminum-based plate making materials in terms of alkali resistance. There is. Furthermore, by performing treatment with phosphoric acid or water-soluble phosphate after treatment with sol, adhesion to the photosensitizer and hydrophilicity after removal of the photosensitizer are improved.

[Table] Comparative Example 1 shows an example in which phosphoric acid treatment was performed without sol treatment, and Comparative Example 2 shows an example in which phosphoric acid treatment was not performed. The metal plates for plate materials of Examples 1 to 4 and Comparative Examples 1 to 3 were coated with a negative type photosensitive resin (manufactured by Ueno Chemical Industry Co., Ltd.), and an image pattern was printed with ultraviolet light and developed to obtain an image. Ta. When printing tests were conducted on the plates thus prepared, no abnormality was observed in Examples 1 to 4 even after printing 50,000 sheets, but in Comparative Example 1, the image peeled off after 2,000 sheets. Comparative example 2 is 40,000 sheets, comparative example 3 is
Some images peeled off after 20,000 copies.

Claims (1)

[Claims] 1. Thickness of 30 to 30 μm with surface roughness of 0.1 to 2 μm.
The surface of a 250 μm steel plate is subjected to one of the following surface treatments A to D: A: Cr, Ni, Sn, Cu, or Zn plating treatment; B: 2 of Cr, Ni, Sn, Cu, or Zn. C: Plating of an alloy containing one or more of Cr, Ni, Sn, Cu or Zn; D: After plating of A, B or C, chromium Chemical conversion treatment with acid salts, dichromates, phosphates, molybdates, borates or perborates, followed by metal oxide sol or metal hydrated oxide sol with a particle size of 1 to 500 nm. A method for producing a metal plate for printing plates, which is immersed in a bath or cathodically treated, and then dipped or cathodically treated in a solution containing phosphoric acid or a water-soluble phosphate in the pH range of 0.5 to 7.0. 2 The amount of phosphorus compounds deposited by phosphoric acid or water-soluble phosphate treatment is calculated in terms of phosphorus.
The method for producing a metal plate for plate material according to claim 1, wherein the content is 0.05 to 10 mg/dm ² .