JPH026637B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a metal plate for planographic printing that has excellent hydrophilicity. Normally, lithographic printing takes advantage of the immiscibility of water and oil, and an image area that is lipophilic (ink-philic) and a non-image area that is hydrophilic are created on the lithographic surface. During printing, when the entire surface of the plate is soaked with water, the oleophilic image area repels the water, while the non-image area retains water, and when oil-based ink is applied to this, the ink remains only on the image area. The image on the plate is transferred to paper or the like directly or via a blanket roll or the like. Photography and printing methods are available as methods for creating ink-friendly images on printing plates, and these methods create images of ink-friendly materials made of photosensitive resins, thermosetting resins, ultraviolet curing resins, etc. is formed on the printing plate. In the case of a metal printing plate, a hydrophilic metal surface is exposed in a non-image area other than an ink-philic image area. The hydrophilicity of non-image areas is particularly important when evaluating printability and the lifespan of printing plates, and if there are areas in non-image areas that are poorly hydrophilic, that is, areas that easily repel water, the printed matter may have stains or Spots, or in extreme cases, the entire surface becomes dirty. Furthermore, if the hydrophilic state does not continue for a long time and it deteriorates, the life of the plate will be short and long-term storage will not be possible. From this point of view, various treatments have been applied to metal plates for printing, but their hydrophilicity has not yet been sufficiently improved, and hydrophilicity changes over time, leaving problems with storage, plate life, etc. There is. Furthermore, in order to make printed matter clearer, there is a tendency to make the ink-friendly image on the metal plate finer, and this requires stronger adhesion between the metal plate and the ink-friendly image. An object of the present invention is to provide a method for obtaining a printing metal plate that has excellent hydrophilicity, maintains this hydrophilicity over a long period of time without deteriorating, and has excellent adhesion to an ink-friendly substance. It is something to do. The gist is that a metal plate with a surface roughness of 0.1 to 3 μm,
Alternatively, on a metal plate that has been subjected to surface treatment such as plating or chemical conversion treatment with a surface of the same roughness,
500nm Al, Ti, Zr, Si, Cr, Ni, Zn, Sn,
The metal plate is immersed in a solution containing at least one kind of sol of a metal compound consisting of oxides or hydrated oxides of Mn, Cu, Co, Fe, Pb, Cd, Mg, or Ca, or the metal plate is used as a cathode. This is a method for producing printing metal plates with excellent hydrophilic properties, which are electrolytically treated as follows. The present invention will be explained in detail below. The metal plate used in the printing metal plate of the present invention is steel, aluminum, zinc, copper, etc. manufactured by a rolling method, or an alloy mainly made of these metals.
10 to 400 μm plates (including foil), as well as iron, copper, nickel, etc. thicknesses of 10 to 400 μm by electroforming.
It is a 400μm plate (including foil). In order to maintain good hydrophilicity, it is preferable that the average surface roughness Ra (JIS B 0601) be in the range of 0.1 to 3 μm, and if it is 0.1 μm or less, the surface will be nearly smooth and the hydrophilicity will be reduced. Not enough, also 3μm
If it is more than that, it will be too rough and the image will bleed during printing, making it impossible to obtain good printed matter. Methods to obtain a surface roughness suitable for hydrophilicity include mechanical methods such as graining, chemical methods such as etching the metal surface with a chemical solution, thick plating on the metal plate surface by electrolysis, or There are electrochemical methods for etching. Plates produced by electrolysis, such as iron foils or copper foils produced by electroforming, have one side that already has a roughness suitable for hydrophilicity, so there are cases where it is not necessary to roughen the surface. many. The metal plate may be used as is, but if the metal plate is a copper plate or electrolytic iron foil, it is preferable to perform surface treatment. Surface treatments include Cr, Ni, Cu, Sn, Zn,
Plating processing methods such as single-layer plating of metals such as Fe, multi-layer plating that combines two or more of these metals, and alloy plating that includes one or more of these metals, or chrome acid salts, dichromates, phosphates, molybdates, silicates,
Chemical conversion treatment methods include immersion in solutions containing borates, perborates, aluminates, etc., or electrolysis. Such surface treatment is applicable not only to copper plates and electrolytic iron foils but also to other metal plates. Some metal plates with the aforementioned surface roughness and metal plates with surface treatments exhibit some degree of hydrophilicity, but most metal plates are insufficiently hydrophilic and moreover, their hydrophilicity deteriorates over time. Since the damage is significant, the treatment is performed again in a solution containing a sol of a metal compound. This treatment may be performed on one side of the metal plate that will become the plate, or on both the front and back sides. The sol of the metal compound, which is the main component in the treatment solution, is composed of an oxide or a hydrated oxide, and is a positively charged water-dispersible sol in the solution. Metals that form such sol include Al, Ti, Zr, Si, Cr, Ni, Zn,
These include Sn, Mn, Cu, Co, Fe, Pb, Cd, Mg, Ca, and all other metals that are positively charged in aqueous solution. The particle size of the metal compound sol that is preferable for hydrophilic treatment of printing metal plates is 1 to 500 nm, and if it is 500 nm or more,
The adhesion of the sol to the metal plate is non-uniform, and therefore the hydrophilicity is also non-uniform, and if the sol is less than 1 nm, it is difficult to produce the sol, making it extremely expensive and lacking in economic efficiency. In order to improve the stability of the metal sol in an aqueous solution, an inorganic acid such as chromic acid or phosphoric acid, an organic acid such as citric acid or acetic acid, or a surfactant may be added to the treatment solution. Further, two or more kinds of sols of the above-mentioned metal compounds may be added to the treatment liquid. The concentration of the sol of this metal compound is preferably 1 to 100g/.If it is less than 1g/, it will have no effect on hydrophilicity, and if it is more than 100g/, it will not affect hydrophilicity, but it will significantly deteriorate the appearance and may cause drag-out. This is not desirable as it wastes sol. A sol of a metal compound has a positive charge in an aqueous solution and is easily adsorbed to a metal plate, and the bond after adsorption is strong, so simply immersing it in the treatment liquid is effective. In addition, even if it is dried as it is after immersion or washed with water and then dried, it shows good hydrophilicity, and the hydrophilic state lasts for a long time. Furthermore, since the sol is positively charged,
If electrolysis is carried out using the metal plate as a cathode, the sol will migrate and be adsorbed, and the bond between the sol and the metal plate will become even stronger. Also, chromic acid for stabilizing the sol.
When treated with a solution containing phosphoric acid, a hydrophilic film with excellent corrosion resistance is formed, which is particularly preferable for treating steel plates, electrolytic iron foils, etc. It is permissible to add acetic acid, hydrochloric acid, sulfuric acid, etc. as an acid for sol stabilization, and since these acids are easily removed by washing with water, they do not cause a decrease in corrosion resistance. The hydrophilic film on the metal plate surface obtained in this way is strongly bonded to the metal plate, so
It does not deteriorate over time. Furthermore, since the processing liquid is neutral or weakly acidic and does not contain alkali ions, it has good adhesion to the ink-friendly resin, so there is no problem of image separation during printing, and more printing can be done with the same plate than before. This will be explained in detail in Examples below. Example 1 Electroformed iron foil with a thickness of 40 μm and an average surface roughness of 0.9 μm was heated in a Surgeest bath at a temperature of 45°C and a current density.
Cr plating with a thickness of 0.1 μm was performed under the conditions of 40 A/dm ² , and 30 g of alumina sol (Alumina Sol-200, manufactured by Nissan Chemical) with a particle size of 500 nm and 5 g of chromic acid were applied.
A hydrophilic film was obtained on the Cr-plated iron foil by immersing it in an aqueous solution containing Cr and drying it. Next, a 250 μm paper was laminated on one side with an adhesive to obtain a metal plate for printing. Example 2 One side of a 0.3 mm thick steel plate was etched with a Baumey 40° ferric chloride solution to reduce the average surface roughness.
It was roughened to 0.7 μm. This is done using a Watts bath and the temperature
Nickel under the conditions of 50℃ and current density of 5A/ ^dm2 .
20g of Cr sol with 1μm plating and flow diameter of 100nm,
Electrolysis was performed using a solution containing 10 g of limonic acid for 30 seconds at a current density of 2 A/dm ² using a steel plate as a cathode, followed by washing with water and drying to obtain a metal plate for printing. Example 3 400g of iron sulfate was applied to one side of a 0.25mm thick steel plate.
Using an iron plating bath containing 100 g of ammonium sulfate, the temperature
Iron plating was performed to a thickness of 50 μm at 50° C. and a current density of 5 A/dm ² to obtain an iron-plated steel plate with a surface roughness of 1.6 μm. Add to this 60g of Ti sol with a particle size of 70nm/
, electrolyzed with a solution containing 5 g of chromic acid for 20 seconds at a current density of 4 A/dm ² using a steel plate as a cathode.
A metal plate for printing was obtained by washing with water and drying. Example 4 Electroformed iron foil with a thickness of 100 μm and an average surface roughness of 2.5 μm was heated in a Watts bath at a temperature of 50°C and a current density of 5 A/d.
Nickel was plated to a thickness of 0.2 ^μm under the conditions of 45°C and current temperature of 40A/ ^dm2 using a sergeant bath.
After plating 0.5 μm of Cr under the conditions of
In a solution containing 10 g of Zr sol and 5 g of phosphoric acid, treatment was performed for 30 seconds at a current density of 2 A/dm ² using the electrocast iron foil as a cathode, and then dried. Then thickness 0.2mm
The polyprofilms were laminated with adhesive to obtain a metal plate for printing. Example 5 A steel plate with an average roughness of 0.1 μm was obtained under the same conditions as in Example 2, and chromium plating was applied to it to a thickness of 0.1 μm using a sergeant bath at a temperature of 45°C and a current density of 40 A/ ^dm2.
A metal plate for printing was obtained by electrolytic treatment for 30 seconds at a current density of 2 A/dm ² using a steel plate as a cathode in an aqueous solution containing 50 g of alumina sol having a particle size of 500 nm and 5 g of chromic acid. Comparative Example 1 A steel plate whose surface was roughened under the same conditions as Example 2 and had a surface roughness of 0.7 μm was plated with 0.1 μm of chromium using a sergeant bath at a temperature of 45°C and a current density of 40 A/dm ^2. did. No treatment was carried out with solutions containing metal sol compounds. Comparative Example 2 A steel plate with a thickness of 0.3 mm and an average roughness of 0.05 μm was plated with chromium to a thickness of 0.1 μm using a sergeant bath at a temperature of 50°C and a current density of 40 A/dm ² .
In an aqueous solution containing 30 g of 50 nm alumina sol (Alumina Sol-200, manufactured by Nissan Chemical) and 5 g of chromic acid, the current density was 2 A/dm ² using a steel plate as a cathode.
A metal plate for printing was obtained by electrolytic treatment for 30 seconds under the following conditions. The hydrophilicity of the printing metal plates prepared as in Examples 1 to 5 and Comparative Examples 1 to 2 was examined immediately after production and after being left indoors for 3 months with the printed surface exposed. Hydrophilicity is evaluated by the contact angle when water is dropped onto the plate. If the contact angle is 30° or less, mark it with ○, if it is between 30° and 50°, mark △, and if it is 50° or more, mark x. . As Comparative Example 3, a commercially available aluminum-based plate-making material was also measured. The results are shown in Table 1.

【table】

[Table] As shown in the table above, the printing metal plates of Examples 1 to 5 according to the present invention had better hydrophilicity and durability of hydrophilicity, and in particular, in terms of durability of hydrophilicity, they were better than commercially available aluminum-based plate making materials. It is excellent. Comparative example 1
Comparative Example 2 shows an example in which no hydrophilic treatment was performed, and Comparative Example 2 shows an example in which the surface roughness is small. Regarding the printing metal plates of Examples 1 to 5, a positive photosensitive resin (FPPR manufactured by Fuji Yakuhin) was applied on these plates.
The image pattern is printed using ultraviolet light.
It was developed to obtain an image. When a printing test was conducted on the plate thus prepared, no abnormality was observed even after printing 10,000 sheets.

Claims (1)

[Claims] 1. Thickness with surface average roughness of 0.1 to 3 μm.
The surface of a metal plate with a diameter of 10 to 400 μm is coated with a particle size of 1 to 500 nm.
Al, Ti, Zr, Si, Cr, Ni, Zn, Sn, Mn, Cu,
A method for producing a metal plate for printing plates, which is immersed or electrolytically treated in a bath containing one or more metal oxide sols or metal hydrated oxide sols of Co, Fe, Pb, Cd, Mg, or Ca. 2. Manufacture of a metal plate for a printing plate according to claim 1, wherein the metal plate is a plate or foil of steel, aluminum, zinc or copper manufactured by a rolling method, or an alloy containing any of these metals. Law. 3 The metal plate is iron manufactured by electroforming,
2. A method for producing a metal plate for plate material according to claim 1, which is a copper or nickel plate or foil. 4. The method for manufacturing a metal plate for a printing plate according to claims 2 to 3, wherein the plate or foil is produced as it is by rolling or electrolytic casting. 5 The plate or foil has Cr, Ni, Cu,
A method for producing a metal plate for a printing plate according to claims 2 to 3, which is plated with Sn, Fe, or Zn. 6 The plate or foil has Cr, Ni, Cu,
4. The method for producing a metal plate for a printing plate according to claim 2, wherein the metal plate is plated with an alloy containing one or more of Sn, Fe, or Zn. 7 The plate or foil has Cr, Ni, Cu,
4. The method for producing a metal plate for a printing plate according to claim 2, wherein the metal plate is multi-layered with two or more types of Sn, Fe, or Zn. 8 The board or foil has its surface treated with a chromate, dichromate, phosphate, acid phosphate, molybdate, silicate, borate, perborate or aluminate. A method for manufacturing a metal plate for plate material according to claims 4 to 7, which is a method of manufacturing a metal plate for a plate material according to claims 4 to 7.