JPS62140894A - Aluminum alloy support for planographic plate - Google Patents

Abstract

PURPOSE:To provide the titled base suitable for an electrochemical roughening treatment, having excellent fatigue strength, thermal softening characteristics and printability and less susceptible to contamination of non-image parts, by forming the titled base from an aluminum alloy containing 0.05-0.20 (exclusive) wt% of Fe, the balance being Al and unavoidable impurities. CONSTITUTION:Ti is added to Al for the purpose of enhancing the strength and thermal softening resistance of the titled base without adversely affecting roughenability or printability and for preventing the elongation after cold rolling from being lowered. If the Ti content is less than 0.05wt%, the thermal softening resistance is insufficient, and the elongation after cold rolling is low. On the other hand, if the Ti content is not less than 0.20wt%, a uniform roughened surface can not be obtained by an electrochemical surface roughening method, and coarse grains of TiAl3 is formed, which causes contamination at the time of printing or the like. Although Fe is effective in enhancing fatigue strength, if the Fe content exceeds 0.50wt% or the Si content exceeds 0.20wt%, an Al-Fe-Si compound or an Al-Fe compound is formed, resulting in that contamination at the time of printing is liable to occur. An Al alloy base having an elongation of not less than 5% and a stiffness in terms of proof strength of not less than 10kg/mm<2> is satisfactory for practical use. Then, electrochemical graining in conducted, chemical etching is performed by using an acid or an alkali and, if required, anodic oxidation, a chemical conversion treatment or the like is conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an aluminum alloy support used in lithographic printing plates, which is particularly suitable for electrochemical roughening treatment and has excellent fatigue strength, thermal softening properties, and printability. This invention relates to an aluminum alloy lithographic printing plate support which is excellent and does not easily stain in non-image areas.

Conventional technology Conventionally, what has been widely used as a lithographic printing plate is the so-called PS, which is made by coating a photosensitive substance on an aluminum plate that has undergone surface treatments such as roughening treatment and anodizing treatment, and then drying it.
A printing plate obtained by subjecting a plate to plate-making processes such as image exposure, development, and gumming.

The photosensitive layer that remains undissolved by this development process forms an image area, and the area where the photosensitive layer is removed and the underlying aluminum surface is exposed becomes a water receiving area because it is hydrophilic, forming a non-image area. is a well-known fact.

As a support for such a lithographic printing plate, an aluminum plate is generally used, which is lightweight and has excellent surface treatment properties, workability, and corrosion resistance. Conventional materials used for this purpose include JIS
A 1050 (A1 alloy with purity of 99.5% by weight or more)
, JIS A 1100 (Al-0.05~0.2
0 wt% Cu alloy), JIS A 3003 (A
! -0,05~0,20% by weight Cu-1,5% by weight Mn
There are aluminum alloy plates with a thickness of 0.1 to 0.5 m, such as aluminum alloys, whose surfaces are processed using one or a combination of mechanical, chemical, and electrochemical methods. The surface is roughened and then subjected to 9A anodic oxidation treatment before use.

Specifically, an aluminum lithographic printing plate subjected to mechanical roughening treatment, chemical etching treatment, and anodic oxidation film treatment described in JP-A-48-49501, or JP-A-51- Aluminum lithographic printing plates were sequentially subjected to chemical etching treatment and anodic oxide film treatment as described in No. 61304, and electrochemical treatment, post-treatment, and anodic oxide film treatment as described in JP-A-54-146234. Aluminum lithographic printing plate, Special Publication No. 48-28123
An aluminum lithographic printing plate that has been subjected to electrochemical treatment, chemical etching treatment, and anodic oxide film treatment as described in the issue, or after mechanical roughening treatment.
Aluminum lithographic printing plates subjected to the treatment described in No. 8123 are known.

By providing a suitable photosensitive layer on such a support, it is possible to obtain up to 100,000 sheets of clear printed matter. However, there is a desire to obtain more printed matter from one printing plate (improvement of printing durability). To achieve this purpose, it is effective to expose and develop a PS plate using an aluminum alloy plate as a support in the usual way, and then heat it at a high temperature (so-called burnigation treatment) to strengthen the image area. The specific method is as follows:
It is described in detail in No. 27243 and Japanese Patent Publication No. 44-27244@. The heating temperature and time for such a burning process depend on the type of resin forming the image, but
The range is usually 3 to 7 minutes in the range of 00 to 280'C.

Problems to be Solved by the Invention In recent years, regarding the above-mentioned burning process, it has been desired to perform the burning process at a high temperature and for a short time in order to shorten the burning process time and improve work efficiency. However, when the conventionally used aluminum alloy plate is heated to a high temperature of 280°C or higher, the aluminum recrystallizes, resulting in an extremely low strength and a loss of stiffness of the printing plate, making it extremely difficult to handle. This results in drawbacks such as the inability to set the plate on the printing press and the inability to register the colors of the plate in multicolor printing. Therefore, a stable aluminum alloy support with high heat resistance is desired.

On the other hand, as printing speeds have increased with the advancement of printing technology, the stress applied to the printing plates that are mechanically fixed to both ends of the printing press cylinder has increased, which may cause the aluminum printing plates to lack strength. This fixed part often becomes deformed or damaged, causing problems such as printing misalignment, or the plate breaks (grip breakage) due to repeated stress applied to the folded part of the printing plate, making printing impossible.

However, conventional JIS A 1050 aluminum alloy plates can provide uniform roughness or appropriate surface roughness through electrochemical roughening treatment, and stains in non-image areas during printing are less likely to occur, but they have poor durability. Poor fatigue strength and heat softening properties. On the other hand, JIS A 3003 aluminum plywood has sufficient fatigue strength and heat softening resistance, but it cannot obtain a uniform rough surface or an appropriate surface roughness through electrochemical roughening treatment, and also has roughness during printing. There is also a drawback that stains tend to occur in non-image areas.

This invention was made against the background of the above-mentioned circumstances, and at the same time has sufficient fatigue resistance and heat softening resistance as a printing plate, and at the same time, it has a uniform roughness and an appropriate surface roughness through surface roughening treatment, especially electrochemical surface roughening treatment. The purpose of the present invention is to provide an aluminum alloy support which can obtain a high surface roughness and which is less likely to cause stains in non-image areas during printing.

Means for Solving the Problems The lithographic printing plate support of the present invention contains Ti0.0 in weight%.
5 to less than 0.20%, Si0.20% or less, Fe0.5
It is composed of an aluminum alloy containing 0% or less and the remainder consisting of A1 and unavoidable impurities.

First, the reasons for limiting the components of the aluminum alloy used in the support of the present invention will be explained.

0 If it is less than .95%, the heat softening resistance will be insufficient and the elongation after cold rolling will be low. On the other hand, Ti0.
If it exceeds 20%, a uniformly roughened surface cannot be obtained by electrochemical roughening, and T! This is not preferable because it forms a coarse compound called Af3, which causes stains during printing. Therefore T
i was 0.05% or more and less than 0.20%.

Fe has the effect of improving fatigue strength. However, Fe
When Si exceeds 0.50% and Si exceeds 0.20%, these components become Al-Fe-8i compounds and Al-Fe-8i compounds.
This is not preferred because it forms a compound and tends to cause stains during printing. Therefore, Fe is 0.50% or less and Si is 0.
．． It was set to 20% or less.

Note that the purpose of the present invention will not be impaired if the other impurities contained in the aluminum alloy are at the level of impurities contained in normally commercially available Al metals.

In manufacturing the aluminum alloy of this invention,
It is made into a thin plate by continuous casting using a mold, or by solidifying between a pair of cooled rolls or cooling plates, and then hot rolling, cold rolling, and, if necessary, intermediate annealing. This intermediate annealing may be either batch annealing in which the coil is annealed in a stationary manner, or so-called continuous annealing in which the coil is annealed while being continuously unwound.

By the way, in order to further improve the fatigue strength and heat softening resistance of the aluminum alloy support according to the present invention, it has been found that it is effective to reduce the residual stress accumulated in the support. Ta. Therefore, as a result of changing the final cold rolling amount and final annealing temperature to change the material strength and elongation, and examining the correlation with fatigue life, it was found that the fatigue life is sufficient if the elongation is 5% or more. Further, as long as the rigidity as a lithographic printing plate support is 10 kg/- or more in yield strength, there is no problem in practical use. The desired yield strength is 15! j /
mm or more.

As a specific method for obtaining these material properties, generally cold rolling after hot rolling or intermediate annealing is performed at a rolling reduction of 10 to 50%, but cold rolling at a rolling reduction of 50% or more is generally recommended. When rolling is performed, the temperature is 150 to 32 after finishing cold rolling.
It is sufficient to perform a softening treatment at 0'C. However, the aluminum alloy having the composition of the present invention has an excellent feature of having sufficient elongation even when the rolling reduction ratio of cold rolling is high. In other words, by adding Ti, there is little decrease in elongation even if cold rolling is continued, for example, 99
% even after cold rolling, elongation of 5% or more can be maintained.
Even if cold rolling is performed at a rolling reduction of more than 0%.

The subsequent softening treatment can be omitted. However, even in that case, it is of course possible to perform a softening treatment at 150 to 320°C after cold rolling.

Next, the method for surface treatment of an aluminum alloy support for a lithographic printing plate according to the present invention will be explained in detail.

Graining methods applied to the aluminum alloy support of the present invention include an electrochemical graining method in which electrochemical graining is carried out in an acid or nitric acid electrolyte, and a wire brush graining method in which the aluminum surface is scratched with a metal wire. Mechanical graining methods such as the pole grain method, in which the aluminum surface is grained using an abrasive bed and an abrasive, and the brush grain method, in which the surface is grained with a nylon brush and an abrasive, can be used. Either graining method can be used alone or in combination.

The electrochemical graining method has the advantage that a uniform rough surface or appropriate surface roughness can be obtained, and that non-image areas are less likely to be smudged during printing.

The thus grained aluminum is chemically etched using a metal or alkali.

When an acid is used as an etching agent, it takes too much time to destroy the fine structure, so it is usually desirable to use an alkali as an etching agent.

Examples of alkaline agents suitably used in this invention include caustic soda, soda carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, and lithium hydroxide, and the preferred ranges of concentration and temperature are 1 to 1.
50% and 20 to 100'C, and these conditions are preferably set so that the amount of aluminum dissolved is 5 to 20 g/m.

After etching, pickling is performed to remove dirt (smut) that remains on the surface. Examples of acids that can be used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and hydrofluoric acid. Particularly, for smut removal treatment after electrochemical surface roughening treatment, there is a method of contacting with 15 to 65% by weight of sulfuric acid at a temperature of 50 to 90°C as described in JP-A-33-12739, and An alkaline etching method such as that described in No. 48-28123@ is preferred.

The aluminum plate treated as described above can be used as a support for a lithographic printing plate, but it is preferable to further perform treatments such as anodization coating treatment and chemical conversion treatment as necessary.

The anodic oxidation treatment can be performed by a method conventionally used in this field. Specifically, direct or alternating current (S) is passed through the aluminum plate in an aqueous or non-aqueous solution containing sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, or a combination of two or more of these acids. By anodizing the surface of the aluminum support! ! ! can be formed.

The conditions for anodizing treatment vary depending on the electrolyte used, so it cannot be generalized, but generally the electrolyte concentration is 1 to 80%, the solution temperature is 5 to 70'C, and the current density is 0.5. ~
60 amperes/play, voltage 1~100■, electrolysis time 10~
A range of 100 seconds is appropriate.

Among these anodic oxide coating treatments, British Patent No. 14
Preferred are the method of anodizing in sulfuric acid at high current density as described in U.S. Pat.

The anodized aluminum plate is further described in U.S. Patent No. 271
No. 4,066 and No. 3,181,461, by immersion in an aqueous solution of an alkali metal silicate, such as sodium silicate, or a water-soluble metal salt, as described in U.S. Pat. No. 3,860,426. A subbing layer of hydrophilic cellulose (such as carboxymethylulose) containing (such as zinc acetate) may also be provided.

On the aluminum alloy support for lithographic printing plates according to the present invention, a photosensitive layer conventionally known as a photosensitive layer of a PS plate can be provided to obtain a photosensitive lithographic printing plate, which is subjected to plate-making processing. The obtained lithographic printing plate has excellent performance.

The composition of the photosensitive layer includes the following.

■Photosensitive layer consisting of diazo resin and binder A reaction product of a diazonium salt and an organic condensing agent containing a reactive carbonyl group such as aldol or acetal, as disclosed in U.S. Pat. Nos. 2,063,631 and 1,667,415. A condensation product of diphenylamine-P-diazonium salt and formaldehyde (so-called photosensitive diazo resin) is preferably used. Other useful condensed diazo compounds are Japanese Patent Publication Nos. 49-48001 and 49-4532.
No. 2, No. 49-45323, etc.

These classes of photosensitive diazo compounds are usually obtained in the form of water-soluble inorganic salts and can therefore be coated from aqueous solution.

Or these water-soluble diazo compounds are
No. 7, the substantially water-insoluble reaction product is reacted with an aromatic or aliphatic compound having one or more phenolic hydrogen groups, sulfonic acid groups, or both. Photosensitive diazo resins can also be used. It can also be used as a reaction product with hexafluorophosphate or tetrafluoroborate as described in JP-A-56-121031. In addition, diazo resins described in British Patent No. 1312925@ are also preferred.

(2) Photosensitive layer consisting of an 0-quinonediazide compound Particularly preferred O-quinonediazide compounds are 0-naphthoquinonediazide compounds, such as U.S. Pat.
No. 59112, No. 2907665@, No. 30461
No. 10, No. 3046111, No. 3046115, No. 3046118, No. 3046119, No. 3046120@, No. 3046121, No. 304
No. 6122, No. 3046123@, No. 306143
No. 0, No. 3102809, No. 3106465,
It is described in a large number of publications including the same No. 3635709 and the same No. 3647443, and these can be suitably used.

■Photosensitive layer consisting of an azide compound and a binder polymer compound, for example, British Patent No. 1235281, British Patent No. 149586
No. 1, JP-A-51-32331, JP-A No. 51-36128
In addition to the compositions comprising an azide compound and a water-soluble or alkali-soluble polymer compound described in
-5102, 50-84302, 50-843
03 and No. 53-12984, the compositions include a polymer containing an azide group and a polymer compound as a binder.

■Other photosensitive resin layers For example, polyester compounds disclosed in JP-A-52-96696, British Patent No. 112277, British Patent No. 13
No. 13309, No. 1341004, No. 13777
Polyvinyl cinnamate resins described in US Pat. No. 47, etc., and photopolymerizable photopolymer compositions described in US Pat. The thickness of the photosensitive layer provided on the support is about 0.1 to 79
/TIt1 is preferably in the range of 0.5 to 49/Td.

After the PS plate is image exposed, a resin image is formed by processing including development using conventional methods.

For example, the photosensitive layer consisting of a diazo resin and a binder
In the case of a PS plate having a lithographic printing plate, after image exposure, the unexposed portions of the photosensitive layer are removed by development to obtain a lithographic printing plate. In the case of a PS plate having a photosensitive layer (1), after image exposure, the exposed portion is removed by developing with an alkaline aqueous solution to obtain a lithographic printing plate.

Example Hereinafter, it will be explained in more detail based on Examples.

Example 1 Inventive alloy A and comparative alloy B shown in Table 1 were cast by a normal method, and both sides were cut to a thickness of 500 m and a width of 10 m.
The ingot is made into an ingot with a length of 00m and a length of 3500m, subjected to homogenization treatment as necessary, hot rolled and cold rolled to a thickness of 1.5M, intermediately annealed at 360°C for 1 hour, and then cold rolled. Finish cold rolling with a rolling reduction of 80%, finish annealing if necessary, and give 0.30 m as shown in Experiment Nos. 1 to 4 in Table 2.
Made of thick board. Regarding these aluminum alloy plates,
Electrolytic etching properties, fatigue strength, heat softening resistance, and resistance to staining of non-image areas were evaluated by the following methods. The results are shown in Table 2.

(1) Electrolytic etching properties The surface condition was observed with a scanning electron microscope to evaluate the uniformity of pits, and excellent results were marked with an O mark, good results with a Δ mark, and poor results with an X mark.

(2) At one end of the specimen bent at 90' at the corner of fatigue strength 2#R,
A tensile load of GF/m- was repeatedly applied at 25H2,
The number of load repetitions until breakage was measured.

Practically speaking, 80,000 times or more is desirable.

(3) Burning processor 1300 with heat resistance and softening properties [Burning processor made by Fuji Photo Film ■ with a heat source of t2kw]
The sample was heated in the chamber at 300°C for 7 minutes.

After cooling, the degree of dullness was sensory evaluated by hand.

(4) Difficulty in staining non-image areas Printing plates treated with the following method are used in an offset printing machine KOR.
The sample was loaded and the degree of staining in the non-image area was evaluated.

The printed version was prepared as follows.

After graining an aluminum alloy plate with a rotating nylon brush in a suspension of bumiston and water, the dissolution amount of aluminum was 8 y/m using a 20% aqueous solution of caustic soda.
It was etched so that

After thoroughly washing with running water, pickling with 25% nitric acid aqueous solution,
Washed with water. This substrate was subjected to alternating current electrolysis at a current density of 20 A/IM or higher in an electrolytic bath containing ~2.5% nitrate as described in JP-A-54-146234@. After cleaning the surface by immersing it in an aqueous solution of 15% sulfuric acid at 50'C for 3 minutes, an oxide film of 39/m was formed at a bath temperature of 30'C in an electrolytic solution containing 20% @acid as the main component. Established.

The following photosensitive layer was provided on the sample prepared in this way so that the coating amount when dried was 2.59/min.

Ester compound of naphthoquinone-1,2-diazido-5-sulfonyl chloride and pyrogallol acetone resin (as described in Example 1 of U.S. Pat. No. 3,635,709) 0.75 cJ Cresol Novolak Resin 2.00 g Oil Blue 1
603 (manufactured by Orient Chemical Co., Ltd.) 0.049 ethylene dichloride 16 g 2-methoxyethyl acetate 12 Ij The photosensitive planographic printing plate thus obtained was heated to 1 TrL with a 3 kW metal halide ν pump.
The film was exposed imagewise for 60 seconds from a distance of 1.5%, developed with a sodium silicate aqueous solution having a molar ratio of 5102/Na2O of 1.2 and a SiO2 content of 1.5%, washed with water, dried, and then gummed.

As is clear from Tables 1 and 2, the supports of experiment numbers NO41 and NO12 using the alloys of the present invention had high fatigue strength and excellent heat softening resistance, as well as good electrolytic etching properties. Moreover, it was also excellent in stain resistance in non-image areas. On the other hand, comparative alloy B is a conventionally used A1 alloy, and in this case, it is clear that No. 3, which is not subjected to final annealing, has low elongation and is inferior in fatigue strength and heat softening resistance. Also, comparative alloy B
N was finish annealed to improve fatigue life.
In No. 014, the material strength is too low, causing stains in non-image areas during printing, making it impractical.

Example 2 Inventive alloy C and comparative alloys D to G shown in Table 2 were cast by a conventional method, and each alloy ingot was hot-rolled and cold-rolled by a conventional method to a plate thickness of 3.5 mm. It was made into OM, then intermediate annealed at 360° C. for 2 hours, and then finished cold rolled at a rolling reduction of 90% to obtain aluminum alloy thin plates with a thickness of 0 and 3 degrees.

Performance evaluations similar to those in Example 1 were performed for each alloy thin plate. The results are shown in Table 4.

As is clear from Table 4, the alloy C of the present invention, in which the amounts of Sit and Fe are suppressed to appropriate amounts and the strength and elongation are adjusted by adding an appropriate amount of Ti, has an excessive amount of Ti. Comparative alloy, Fe
Comparative alloy E1 with excessive amount S1 Comparative alloy F, T with excessive amount
Unlike comparative alloy G, which has an insufficient amount of i added, it can be seen that it has excellent performance in all aspects of electrolytic etching properties, fatigue resistance, heat softening resistance, and resistance to staining of non-image areas. .

Effects of the Invention As is clear from the above examples, the aluminum alloy support for lithographic printing of the present invention has sufficient fatigue strength and heat softening resistance as a printing plate, and at the same time has excellent electrolytic etching properties and is suitable for electrochemical etching. It is possible to obtain a uniformly roughened surface and appropriate surface roughness through the surface roughening treatment, and also has the excellent performance of being resistant to staining of non-image areas during printing.

Applicant Sky Aluminum Co., Ltd. Fuji Photo Film Co., Ltd.

Claims (3)

[Claims] (1) Aluminum alloy support for lithographic printing plates containing 0.05 to less than 0.20% Ti (weight %, same hereinafter), 0.20% or less Si, and 0.50% or less Fe, with the remainder being Al and unavoidable impurities. body. (2) Yield strength of aluminum alloy support is 10Kg/mm
The aluminum alloy support for a lithographic printing plate according to claim 1, wherein the aluminum alloy support has an elongation at break of ^2 or more and an elongation at break of 5% or more. (3) The aluminum alloy support for a lithographic printing plate according to claim 1 or 2, wherein the surface of the aluminum alloy support is roughened and anodized.