JP2688786B2 - Aluminum alloy support for printing plate - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an aluminum alloy support used for offset printing or lithographic printing, and particularly to an aluminum alloy for a printing plate which is less likely to cause stains in non-image areas during printing. The present invention relates to a support, that is, an aluminum alloy support for a printing plate having excellent resistance to ink stains.

Conventional technology Generally, as an offset printing plate or a lithographic printing plate, the surface of an aluminum alloy base plate is subjected to surface treatment such as surface roughening treatment or anodizing treatment to form a support, and a photosensitive substance is applied onto the support. , Dried into a so-called PS plate,
A PS plate that has undergone image exposure, development, and gum-making plate making processing is used. In the process of the plate making process, the photosensitive layer which remains undissolved by the development process forms an image area, and the portion where the photosensitive layer is removed and the aluminum surface underneath is exposed is a water receiving part due to hydrophilicity. Thus, a non-image portion is formed.

By the way, as a support for such offset printing or lithographic printing, it is generally lightweight and has a surface treatment property,
A rolled aluminum alloy plate with excellent workability and corrosion resistance is used. As the aluminum alloy rolled plate for such a purpose, conventionally, an aluminum alloy rolled plate having a plate thickness of about 0.1 to 0.5 mm made of JIS 1050, JIS 1100, JIS 3003, etc. is used. Is used for printing plates by roughening the surface and then performing anodizing treatment. Specifically, as described in JP-A-48-49501, mechanical surface roughening treatment, chemical etching treatment,
An aluminum lithographic printing plate which has been sequentially subjected to an anodized film treatment, or an aluminum lithographic printing plate which has been subjected to electrochemical treatment, post-treatment and anodizing treatment in sequence as described in JP-A-51-146234. Aluminum lithographic printing plate which has been subjected to the chemical etching treatment and the anodizing treatment described in 48-28123 in order, or the aluminum lithographic printing plate which has been subjected to the treatment described in JP-B-48-28123 after mechanical surface roughening treatment. Printing plates and the like are known.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In actually using the rolled aluminum alloy plate for printing as described above in printing, first, as described above, the raw plate surface is subjected to a mechanical method, a chemical method, or an electrochemical method. After roughening by any one or a combination of two or more processes, an anodic oxide film is formed with an amount of about 0.5 to 4 g / m ² to improve printability, and then a photosensitizer is applied. Then, the plate is exposed to light, subjected to plate making processing such as development, wrapped around a cylindrical plate cylinder of a printing machine, ink is made to adhere to the image portion in the presence of fountain solution, transferred to a rubber blanket, and then printed on a paper surface.

The aluminum alloy rolled plate for printing used as described above is required to have the following characteristics (A) to (E) except for mechanical performance.

(A) Uniform unevenness is formed by the surface roughening treatment.

(B) Adhesion of the photosensitive film is good.

(C) The non-image area should not be stained during printing.

(D) The tone reproducibility of the image area is excellent.

(E) The background color tone (the color tone after the surface roughening treatment) is white so that the image area can be easily seen in the image area inspection after development.

Among these required characteristics, (A) is the most basic characteristic, and if unevenness is formed by the roughening treatment, the characteristics of (B) to (E) are also adversely affected. In addition, sufficient printing durability cannot be obtained. In order to uniformly roughen the surface of the base plate by chemical etching or electrochemical etching, it is necessary to appropriately select the alloy composition of the base plate and the manufacturing conditions. From this point of view, generally, as a bare plate, as described above, pure aluminum JIS 1050 alloy or
1100 alloy, or Al-Mn-based alloy (3003 alloy), further Al-Mg-based alloys have been selected, and recently, materials with further restricted components in these alloys have been developed,
With these, the characteristic (A) itself is achieved to some extent.

By the way, recently, clearer printing is required, and it is desired that a larger number of copies can be printed using the same plate. For that purpose, it is especially important that ink stains do not occur in the non-image area during printing.

The present invention has been made in view of the above circumstances,
In particular, it is an object of the present invention to provide an aluminum alloy support for a printing plate, which is excellent in printability and is less likely to cause ink stains on non-image areas during printing.

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted various experiments and studies on the occurrence of ink stains in the non-image area during printing, and as a result, exist in the anodized film on the surface of the treated body. It was found that the number of intermetallic compounds having a maximum length of 1 μm or more significantly affects the ink stain resistance, and the present invention has been completed.

Specifically, the invention of claim 1 is pure Al-based or Al-
A rolled Mg-based aluminum plate is used as the substrate, the surface of the substrate is roughened, and the anodic oxide film is 0.5 to 4 g / m ²
In an aluminum alloy support for printing plates formed with the production amount of, the number of intermetallic compounds having a maximum length of 1 μm or more in the anodized film is 7,000 or less per 1 mm ^2. Is.

Further, the invention of claim 2 uses an Al-Mn-based rolled aluminum alloy plate as a substrate, and the substrate surface is roughened and an anodic oxide film is formed at an amount of 0.5 to 4 g / m ² . In the aluminum alloy support for printing plates, the number of intermetallic compounds having a maximum length of 1 μm or more in the anodized film was
The feature is that the number is less than 30,000 per 1 mm ² .

Effects The inventors of the present invention have conducted various experiments and studies on the occurrence of stains on the non-image area during printing, and have found the following facts.

That is, if the stress due to repeated printing is combined with the fact that it is wet with dampening water for a long period of time, and the anodic oxide film breaks such as cracks, other aluminum alloys will not be wet with dampening water. It was found that when contact occurs, corrosion occurs, the hydrophilicity decreases at the corroded portion, ink adheres to that portion, and the non-image portion becomes dirty. Further, it was found that such destruction of the anodized film mainly occurred at the interface between the intermetallic compound and the matrix, which were present in the film. From these facts, the number of intermetallic compounds existing in the anodized film, especially the intermetallic compound having a maximum length of 1 μm or more per unit area, has a great influence on the ink stain resistance. It was found that the ink stain resistance can be significantly improved by limiting the number of intermetallic compounds having a maximum length of 1 μm or more per area to a certain value or less.

Actually, the type of intermetallic compound varies depending on the type of aluminum alloy (alloy system) used,
Further, the degree of influence of the number of intermetallic compounds on the ink stain resistance varies depending on the type of the intermetallic compounds.

In pure Al-based aluminum alloys and Al-Mg-based aluminum alloys such as JIS 1050 alloy and 1100 alloy, there are mainly Al-Fe-based and Al-Fe-Si-based intermetallic compounds as intermetallic compounds. In this case, if 7,000 or more intermetallic compounds having a maximum length of 1 μm or more are present in the anodized film per 1 mm ² , the ink stain on the non-image area becomes severe.

On the other hand, in the case of Al-Mn-based aluminum alloys such as JIS 3003 alloy, there are mainly Al-Mn-Fe-based and Al-Mn-Fe-Si-based intermetallic compounds, and in the case of this system, pure The number of intermetallic compounds is essentially higher than in the case of aluminum type or Al-Mg type. However, Al-Mn-Fe and Al-Mn-Fe-
The Si-based intermetallic compound has a smaller potential difference from the matrix than the Al-Fe-based or Al-Fe-Si-based intermetallic compound, and therefore, even if cracks occur in the anodic oxide film, it will lead to corrosion. Since it takes time, it has little effect on the ink stain resistance. Therefore, in the case of Al-Mn-based alloy, the ink stain resistance is better even if the number of intermetallic compounds is larger than in the case of pure Al-based or Al-Mg-based alloy, but the maximum length in the anodized film is 1 μm. If the number of the above intermetallic compounds per 1 mm ² exceeds 30,000, ink stains on non-image areas are likely to occur.

Therefore, when using a rolled plate of pure aluminum or Al-Mg-based alloy as the substrate, the number of intermetallic compounds with a maximum length of 1 μm or more is specified to be 7,000 or less per 1 mm ² , and the substrate of Al-Mn-based alloy is specified. Maximum length of 1 if rolled plate is used
The number of intermetallic compounds having a size of μm or more was defined as 30,000 or less per 1 mm ² .

Note that here, the pure Al-based aluminum alloy is generally
Fe 0.60 wt% or less, Si 0.30 wt% or less and the balance substantially consisting of Al, and Al-Mg type aluminum alloy means Mg
It can be defined as a material containing 3.0 wt% or less as an essential component, Fe 0.60 wt% or less, Si 0.30% or less, and the balance substantially consisting of Al. Further, with Al-Mn-based aluminum alloy, contains Mn 1.2 wt% or less as an essential component, Fe0.6
It can be defined as wt% or less, Si 0.3 wt% or less, and the balance substantially consisting of Al.

As described above, the regulation of the individuality of the intermetallic compound having the maximum length of 1 μm or more is carried out by adjusting the composition of the alloy, chemical roughening treatment conditions or subsequent desmutting conditions, and electrochemical roughening treatment ( This can be achieved by appropriately selecting the conditions for electrolytic graining treatment).

The surface roughening treatment may be performed by one or more of mechanical surface roughening treatment, chemical surface roughening treatment, and electrochemical surface roughening treatment. Among these, mechanical surface roughening treatment is performed. There are a wire brush grain method that scratches the surface of an aluminum alloy rolled plate with a metal wire, a ball grain method that roughens the rolled plate surface with a polishing ball and an abrasive, and a brush grain method that roughens the surface with a nylon brush and an abrasive. There is also a method, and more recently, there is also a method of roughening the surface of the rolled plate by using a roll whose surface is roughened when rolling the aluminum plate. It is rare that the surface of a rolled plate is only subjected to mechanical roughening treatment and then immediately subjected to anodizing treatment for use as a printing plate support. In this case, the number of intermetallic compounds existing in the anodized film is almost equal to the number of intermetallic compounds existing on the surface of the rolled plate before the surface roughening treatment. Therefore, in this case, the number of intermetallic compounds of 1 μm or more on the surface of the rolled plate subjected to the surface roughening treatment may be regulated to the number as described above or less. For that purpose, the amount of Fe or Si of the aluminum alloy may be regulated. good. For example, in the case of an aluminum alloy of pure Al-based aluminum alloy or Al-Mg-based aluminum alloy, the Fe content is 0.20 wt.
% Or less, and the Si content is 0.10 wt% or less, it is possible to reduce the number of intermetallic compounds having a size of 1 μm or more in the anodized film to 7,000 or less per 1 mm ² .

In general, after the mechanical surface roughening treatment, chemical etching for chemical surface roughening treatment or chemical etching for removing stains (smuts) due to the mechanical surface roughening treatment is often performed. When chemical etching is performed in this way, the intermetallic compounds fall off depending on the conditions, and the number of intermetallic compounds decreases considerably. Therefore, in that case, it is not necessary to regulate the Fe content and Si content of the material aluminum alloy. As the chemical etching in this case, it is usual to use an alkali as an etching agent, and as the alkali etching agent, caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide, etc. Is used. The preferred ranges of concentration and temperature are 1 to 50% by weight and 20 to 10%, respectively.
It is preferable to apply conditions such that the temperature is 0 ° C. and the amount of aluminum dissolved is 5 to 20 g / m ² .

After the chemical etching, pickling is usually performed to remove the smut remaining on the surface. Examples of the acid used for this pickling include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and hydrofluoric acid. Further, particularly as the smut removal treatment after the electrochemical surface roughening treatment, contact with sulfuric acid at a temperature of 50 to 90 ° C. and a weight of 15 to 65% by weight as described in JP-A-53-12739. It is desirable to apply the above method or alkali etching as described in JP-A-48-28123.

After the roughening treatment as described above, an anodizing treatment is applied to improve printability. This anodizing treatment is more effective in improving the hydrophilicity of the surface and improving the printing durability, but if the thickness of the anodized film produced is less than 0.5 g / m ^{2 in} terms of the film production amount, these The effects are not sufficiently obtained, and even if the film thickness is increased to more than 4 g / m ² , these effects are not only saturated, but on the contrary, cracks are likely to occur in the anodized film. Therefore, the thickness of the anodized film should be within the range of 0.5 to 4 g / m ² in terms of film formation amount.

As a specific method of this anodizing treatment, a method conventionally used in this field can be used. Specifically, aluminum is supported by applying a direct current or alternating current to an aluminum plate in sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, etc., or an aqueous solution or a non-aqueous solution in which two or more of these are combined. An anodized film can be formed on the body surface.

The condition of the anodizing treatment varies depending on the electrolytic solution used, so it cannot be generally stated, but generally the concentration of the electrolytic solution is 1 to 80%, the liquid temperature is 5 to 70 ° C, and the current density is 0.5 to 60A / d
A range of m ² , voltage of 1 to 100 V, and electrolysis time of 10 to 100 seconds is suitable.

Among these anodic oxide film treatments, the British patent no.
The method of anodizing in sulfuric acid at a high current density described in 1,412,768 and the method of anodizing phosphoric acid as an electrolytic bath described in US Pat. No. 3,511,661 are preferable.

Anodized aluminum alloy sheet is further described in US Pat.
Aluminum metal silicates as described in 2,714,066 and 3,181,461, such as treatment by dipping in an aqueous solution of sodium silicate, or water-soluble metal salts as described in U.S. Pat.No. 3,860,426. An undercoat layer of hydrophilic cellulose (eg, carboxymethyl cellulose, etc.) containing (eg, zinc acetate, etc.) can also be provided.

On the aluminum alloy support for a printing plate according to the present invention obtained as described above, a photosensitive lithographic printing plate can be obtained by providing a photosensitive layer conventionally known as a photosensitive layer of a PS plate, The lithographic printing plate obtained by subjecting this to platemaking has excellent ink stain resistance.

Examples Next, examples of aluminum alloy supports for printing plates according to the present invention will be described together with comparative examples.

450 × 1200 × 3500m by semi-continuous casting method by smelting aluminum alloys with compositional composition shown in alloy No. 1 to 3 in Table 1.
An m ingot was produced. After subjecting the ingot to chamfering on each side by 7 mm, it was treated under the following conditions.

That is, for the pure Al-based No. 1 alloy, after subjecting the ingot to soaking at 560 ° C, it was heated to 450 ° C and hot-rolled to a thickness of 4 m, and then primary cold-rolled to a thickness of 1.5 mm. After that, intermediate annealing was performed at 500 ° C. in a continuous annealing furnace, and further final cold rolling was performed to obtain a 0.3 mm thick H18 temper material.

For the No. 2 Al-Mg alloy, the ingot was soaked at 530 ° C, heated to 450 ° C and hot-rolled to a thickness of 3 mm, and then primary cold-rolled to a thickness of 1.0 mm. After that, intermediate annealing was performed at 350 ° C. in a batch furnace, and final cold rolling was performed to obtain a 0.3 mm thick H18 temper material.

For the Al-Mn No. 3 alloy, the ingot was soaked at 530 ° C, heated to 450 ° C and hot-rolled to a thickness of 3 mm, and then cold-rolled to a thickness of 0.3 mm. And made into H18 temper material.

The rolled plates of the alloys Nos. 1 to 3 obtained as described above were subjected to the surface roughening treatment by the respective methods shown by symbols A to E in Table 2. In Table 2, in the case of the roughening treatment symbols A and B, the chemical roughening treatment is performed after the mechanical roughening treatment, and in the case of the roughening treatment symbol C, In the case of chemical roughening treatment only, in the case of roughening treatment symbols D and E, both chemical roughening treatment is performed after mechanical roughening treatment and electrochemical roughening treatment is performed. It was done. In addition, after each of the chemical surface-roughening treatments in Table 2, desmutting treatment was performed with a 25% nitric acid aqueous solution. After each electrochemical graining treatment, desmutting treatment was performed with 25% H ₂ SO ₄ at 90 ° C for 30 seconds.

After the surface-roughening treatment, anodization treatment was performed in a 25% sulfuric acid electrolytic bath at a liquid temperature of 25 ° C. under the condition of current density of 1.5 A / dm ² to form an anodized film having a film thickness of 0.5 μm.

When the number of intermetallic compounds having a maximum length of 1 μm or more in the anodized film was examined for each plate after the anodizing treatment, the results shown in Table 3 were obtained. The number of intermetallic compounds in the anodized film was examined by observing the plate surface after anodizing with a scanning electron microscope and performing image analysis.

Further, a photosensitive layer having the following composition was provided on the surface of each film after the anodizing treatment so that the coating material when dried was 2.5 g / m ² .

[Photosensitive layer composition] Ester compound of naphthoquinone-1,2-diad-5-sulfonyl chloride, pyrogallol and acetone resin (described in Example 1 of US Pat. No. 3.635,709) ... 0.75 g cresol Novolak resin ...... 2.00 g Oil blue # 603 (manufactured by Orient Chemical Industry Co., Ltd.) ...... 0.04 g Ethylene dichloride …… 16 g 2-Methoxyethyl acetate …… 12 g Each photosensitive lithographic printing plate having a photosensitive layer thus formed About 6 from 1m distance with 3kw metal halide lamp
Image exposure for 0 seconds, then SiO ₂ / Na ₂ O molar ratio 1.2 and SiO ₂
After development with an aqueous sodium silicate solution having a content of 1.5, washing with water and drying, a printing test of 150,000 copies was performed using an offset rotary press. After that, the degree of dot stains on the non-image area was visually evaluated. The results are also shown in Table 3.

As is clear from Table 3, pure alim type or Al-
An example of the first invention in which the number of intermetallic compounds of 1 μm or more in the anodic oxide coating was set to 7,000 or less per 1 mm ² using the Mg-based alloy, and 1 μm in the anodic oxide coating using the Al—Mn-based alloy.
In each of the examples of the second invention in which the number of intermetallic compounds of m or more was 30,000 or less per 1 mm ² , no ink stain was generated in the non-image area even after printing 150,000 copies, and the ink stain resistance was high. Remarkably excellent.

EFFECTS OF THE INVENTION As is clear from the examples, the aluminum alloy support for a printing plate of the present invention can be used for lithographic printing by appropriately controlling the intermetallic compound in the anodized film according to the component system of the alloy. Excellent resistance to ink smearing when used as a printing plate or printing plate for offset printing, and ink stains are less likely to occur in non-image areas during printing, so multiple copies can be continuously printed and a clearer printed image can be obtained. Can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazunari Takizawa 4000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Fuji Photo Film Co., Ltd. (72) Inventor ▲ Sakaki ▼ Hirokazu Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Fuji Photo Film Co., Ltd. (56) References JP-A-61-106297 (JP, A)

Claims (2)

(57) [Claims] 1. A pure aluminum-based or Al-Mg-based rolled aluminum alloy plate is used as a substrate, and the surface of the substrate is roughened and an anodic oxide film is formed at an amount of 0.5 to 4 g / m ^2. In the aluminum alloy support for printing plates, the aluminum alloy support for printing plates is characterized in that the number of intermetallic compounds having a maximum length of 1 μm or more in the anodic oxide film is 7,000 or less per 1 mm ^2. . 2. A printing plate in which an Al-Mn-based rolled aluminum alloy plate is used as a substrate, and the surface of the substrate is roughened and an anodic oxide film is formed at an amount of 0.5 to 4 g / m ² . An aluminum alloy support for a printing plate, characterized in that, in the aluminum alloy support, the number of intermetallic compounds having a maximum length of 1 μm or more in an anodized film is 30,000 or less per 1 mm ² .