JP2665382B2 - Aluminum alloy materials for lithographic printing plates - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an aluminum alloy for a lithographic printing plate which is excellent in electrochemical surface roughening treatment and ink stain resistance, and a method for producing the same.

[Prior Art] Generally, in lithographic printing, the use of an aluminum plate as a support has been conventionally performed, but the surface thereof is roughened from the viewpoint of adhesion of a photosensitive film and water retention of a non-image portion. It is necessary.

As the surface roughening method, there have conventionally been mechanical surface roughening methods such as a ball grain method, a brush grain method, and a wire grain method. However, hydrochloric acid or an electrolytic solution mainly containing the same (hereinafter referred to as hydrochloric acid) has been proposed. A method of electrochemically roughening the surface of aluminum using nitric acid or an electrolytic solution mainly composed of nitric acid (hereinafter referred to as a nitric acid-based electrolytic solution) is employed. The electrochemical surface roughening method has been rapidly developed in recent years because it is excellent in plate making suitability and printing performance and is suitable for continuous treatment of coil materials.

Conventionally, as an aluminum alloy plate for lithographic printing plates, A1100 (aluminum purity 99.9% by weight or more) and A3003 (aluminum purity 98.
0 to 98.5% by weight), and A1050 (aluminum purity: 99.5% by weight or more) is used for electrochemical surface roughening to obtain a relatively uniform electrolytic rough surface. ing. And, when the material equivalent to A1050 which has been electrochemically roughened is used, relatively good printing durability is obtained. Printing durability refers to the maximum number of printed sheets at which a clear printed matter can be obtained.

[Problems to be Solved by the Invention] In recent years, as the information age has advanced, the number of printing copies has increased dramatically, and therefore, the printing durability of a printing plate using a material equivalent to A1050 has become insufficient. Further, as the number of printed sheets increases, the phenomenon that the non-image portion of the printed matter becomes dirty, that is, the ink stain has also become noticeable.

The present invention solves the above-mentioned drawbacks, and has excellent electrochemical surface-roughening treatment properties, and therefore has good printing durability and excellent ink stain resistance, and an aluminum alloy for a lithographic printing plate, and a method for producing the same. The purpose is to provide.

[Means for Solving the Invention] The present invention provides Fe: 0.1 to 1.0%, Si: 0.03 to 0.2%, Cu: 0.00
5 to 0.05%, including Ti: 0.1% or less, Ga: 0.04% or less, remaining
Al and unavoidable impurities, the relationship between Ti and Ga is [Ti
(%)] ≧ 1.2 × [Ga (%)] − 0.015.

[Operation] The components of the present invention will be specifically described.

When the A1050 alloy plate, which has been conventionally used for lithographic printing plates, is subjected to electrochemical surface roughening, pits (hereinafter, referred to as pits)
The pits resulting from electrochemical surface roughening are simply referred to as pits), and are liable to be distorted to have a half-moon shape or to have a shallow pit depth, which adversely affects printing durability. Further, when A1050 alloy is used as a lithographic printing plate, the ink stain resistance is not sufficient.

The present inventors have conducted a careful analysis on the factors affecting the pit shape of the Al-Fe alloy, and found that Ga inevitably contained in the aluminum ingot is the cause of the distortion of the pit shape and suppresses the adverse effect of Ga. In order to obtain fine circular pits, it is effective to add Ti according to the Ga content, and it is effective to add an appropriate amount of Cu. It has been found that it is effective to perform a homogenization treatment at an appropriate temperature. In addition, it has been found that, in order to improve the ink stain resistance, it is effective to properly control the homogenizing treatment temperature and the heating temperature of the hot rolling while making the Si amount appropriate.

 Hereinafter, the alloy composition according to the present invention will be described.

(1) Fe: 0.1 to 1.0% Fe increases the strength of the alloy and makes pits finer. If it is less than 0.1%, the effect is not sufficient, and if it exceeds 1.0%, coarse compounds are increased and pits become non-uniform.

(2) Si: 0.03 to 0.2% Si increases the strength of the alloy and forms an Al-Fe-Si compound, contributing to miniaturization of pits. If it is less than 0.03%, the effect is not sufficient, and if it exceeds 0.2%, the ink stain resistance deteriorates.

(3) Cu: 0.005 to 0.05% Cu increases the depth of the pits to improve printing durability. 0.
If it is less than 005%, the effect is not sufficient, and if it exceeds 0.05%, pits for electrolytic surface roughening are conversely made to be large independent pits.

(4) Ti: 0.1% or less Ti suppresses the action of Ga, which distorts the shape of the pit. The effective amount of Ti added is
It is determined by the following equation according to the amount.

[Ti (%)] ≧ 1.2 × [Ga (%)] − 0.015 This relational expression is derived by experiment,
Interpreted as follows. That is, when Ga dissolved in aluminum exceeds a certain limit, the effect of distorting the pitch shape becomes remarkable, whereas when Ti is added, Ti and Ga form a compound, for example, Ti ₂ Ga to form solid solution Ga. It is considered that the pit becomes a fine circle because the harmful effect of Ga is suppressed as a result. Therefore, as shown in the above equation, Ga
It is necessary to determine the amount of Ti to be added in accordance with the content, so that the pits become fine circles and the printing durability is expected to be improved.

On the other hand, if the Ti content exceeds 0.1%, a coarse compound is formed,
There are many coarse pits.

(5) Ga: 0.04% or less Ga is an impurity inevitably contained in aluminum ingot. Generally, it is often contained in an amount of about 0.004 to 0.020%, but may be further contained when redissolving scrap. Ga has the effect of distorting the shape of the pits and deteriorating the printing durability of the printing plate. To suppress this effect, Ti is added according to the Ga content as described above. However, if the Ga content exceeds 0.04%, the pit distortion cannot be improved even if Ti is added, so the Ga content is specified to be 0.04% or less. It is difficult to completely explain this phenomenon, but it can be interpreted as follows. That is, when the amount of Ga exceeds 0.04%, it is necessary to add a corresponding amount of Ti (0.033% or more). In this case, Ti causes segregation at the time of casting of the alloy, or other compounds such as Al _The formation of 3Ti or the like makes it impossible to distribute the particles uniformly, and the effect is considered to be insufficient.

 Next, the manufacturing conditions will be described.

(1) Manufacturing Step The aluminum alloy support of the present invention is manufactured by the steps of casting, homogenization, hot rolling, cold rolling, intermediate annealing, and finishing cold rolling. However, the homogenization treatment and the heating before hot rolling can also be performed. That is, after the homogenization treatment, hot rolling can be performed as it is, or hot rolling can be performed after cooling to a predetermined temperature.

It is desirable that the conditions in each manufacturing process are as follows. In other words, by manufacturing under the following conditions, the properties of the alloy of the present invention as a material for a lithographic printing plate are more effectively exhibited.

(2) Casting: Performed by an ordinary method. Usually, semi-continuous casting is often used.

(3) Homogenization treatment: 400-600 ° C In the homogenization treatment, Fe, Si
At the same time as binding Ga and Ti in solid solution. As a result, the pits have a fine circular shape, which contributes to an improvement in printing durability. F below 400 ° C
e, Si is not sufficiently precipitated, and the bonding between Ga and Ti is not sufficient, so that the shape of the pit is easily distorted. When the temperature exceeds 600 ° C, the amount of solid solution of Si increases, so that Si alone is likely to precipitate in a subsequent process,
Ink stains easily occur.

(4) Hot rolling Hot rolling is performed by heating to 350 to 600 ° C.

If the temperature is lower than 350 ° C., the degree of deformation per operation cannot be increased due to high deformation resistance, and the number of rolling passes increases, which is not economical. On the other hand, if the temperature exceeds 600 ° C., the amount of solid solution of Si increases, and it becomes easy for single Si to precipitate in a later step, and ink stains are easily generated. On the other hand, if the temperature exceeds 450 ° C., coarse recrystallized grains are generated during hot rolling, and streaks due to a streaky non-uniform structure are likely to occur.

(5) Cold rolling This is performed to make a hot-rolled sheet thin. Rolling degree is normal
Done at 50-95%.

(6) Intermediate annealing Intermediate annealing is performed to recrystallize the material, usually 300 times.
Performed at ~ 550 ° C. It is not necessary to define the method of the intermediate annealing, and a method generally used industrially, that is, a method using a batch furnace or a method using a continuous annealing furnace is adopted.
In the case of annealing in a batch furnace, heating is performed at 300 to 450 ° C. for several hours, but annealing at a high temperature for a long time increases the size of recrystallized grains.
It is appropriate to anneal at 0 to 400 ° C. 40 in continuous annealing furnace
By heating at 0 to 550 ° C. for 0 seconds (no holding) to several tens of seconds, fine recrystallized grains can be obtained. In this case, 400
When held at ~ 550 ° C, the recrystallized grains are coarsened and the strength is reduced, and the printing plate is apt to be cut off.Also, during the holding, the Al-Fe and Al-Fe-Si-based precipitates are coarsened. Since the pits formed by the electrochemical surface roughening treatment become rough, the shorter the holding time, the better, and 0 seconds (no holding) is most desirable.

(7) Finish cold rolling Increases the strength of the material and prevents the grip when the support is wound around the plate cylinder. Rolling degree (thickness reduction rate) is 50
% Or more. If it is less than 50%, the strength will be insufficient, and the effect of preventing rip will be lost.

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

The graining method is an electrolytic surface roughening method in which an alternating current is flowed in a hydrochloric acid-based or nitric acid-based electrolyte to grain. Mechanical surface roughening such as wire brush graining, which scratches the aluminum surface with a metal wire, ball graining, which sands the aluminum surface with abrasive balls and abrasives, and brush graining, which sands the surface with nylon brushes and abrasives The method may be used in combination as an electrolytic surface roughening method.

Prior to electrolytic surface roughening treatment, to remove the rolling oil adhering to the aluminum surface or the abrasive after mechanical surface roughening (if mechanical surface roughening is applied) to clean the surface Is performed. Generally, in order to remove rolling oil, a method of cleaning the surface using a solvent such as trichlene or a surfactant is used. Also, an aluminum alloy plate is placed in an aqueous solution of 1-30% sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, etc. at 20-80 ° C.
Is carried out at a temperature of 5 to 250 seconds for alkali etching, and then immersed in an aqueous solution of 10 to 30% nitric acid or sulfuric acid at a temperature of 20 to 70 ° C. for 5 to 250 seconds to neutralize and remove the smut. It is generally used for removing both rolling oils and abrasives.

After surface cleaning of the aluminum alloy plate, electrolytic surface roughening treatment is performed.

The concentration of the electrolytic solution used for the electrolytic surface roughening treatment when using a hydrochloric acid solution is preferably in the range of 0.01 to 3% by weight, more preferably 0.05 to 2.5% by weight. When a nitric acid solution is used, the concentration is preferably 0.2 to 5% by weight, more preferably 0.5 to 3% by weight.

The electrolyte may contain a corrosion inhibitor (or stabilizer) such as nitrate, chloride, monoamines, diamines, aldehydes, phosphoric acid, chromic acid, boric acid, oxalic acid, etc. A homogenizing agent or the like can be added.

The temperature of the electrolytic solution is usually treated at 10 to 60 ° C. As the alternating current used at this time, any of a rectangular wave, a trapezoidal wave, and a sine wave can be used as long as the positive and negative polarities are alternately converted. Phase alternating current can be used. The current density is 5-100A / dm ²
It is desirable to process for 10 to 300 seconds.

The surface roughness of the aluminum alloy support in the present invention is adjusted by the quantity of electricity and is set to 0.2 to 0.8 μm. 0.8
If the thickness exceeds μm, the extremely roughened surface is covered with macro pits, which causes a reduction in printing durability and causes ink stains, which is not preferable. On the other hand, when the thickness is less than 0.2 μm, the immersion water on the printing plate cannot be controlled, so that the halftone dot portion of the shadow portion becomes liable to be discolored, and a good printed matter cannot be obtained.

Aluminum alloy with such a grain is 10 ~
Smut adhering to the surface is removed by 50% hot sulfuric acid (40-60 ° C) or dilute alkali (such as sodium hydroxide). When removed with alkali, it is subsequently neutralized by immersion in an acid (nitric acid or sulfuric acid) for washing.

After de-smutting the surface, an anodic oxide coating is provided. As the anodic oxidation method, a conventionally well-known method can be used, but sulfuric acid is used as the most useful electrolytic solution. Subsequently, phosphoric acid is also a useful electrolyte. Further, the mixed acid method of sulfuric acid and phosphoric acid disclosed in JP-A-55-28400 is also useful.

In the sulfuric acid method, the treatment is usually performed with a direct current, but an alternating current can also be used. The sulfuric acid is used at a concentration of 5 to 30%, and is subjected to electrolytic treatment in a temperature range of 20 to 60 ° C. for 5 to 250 seconds to provide an oxide film of 1 to 10 g / m ^{2 on} the surface. Further, the current density at this time is preferably 1 to 20 A / dm ² . In the case of the phosphoric acid method, at a concentration of 5 to 50% and a temperature of 30 to 60 ° C, 10 to 10%
300 seconds, at a current density of 1 through 15A / dm ^2, is treated.

Thus, after providing the anodic oxide film, post-processing can be performed as needed. For example, British Patent No. 123044
A method of immersion treatment in an aqueous solution of polyvinylphosphonic acid disclosed in Japanese Patent No. 7 and a method of immersion in an aqueous solution of alkali metal silicate disclosed in US Pat. No. 3,118,461 are used. It is also possible to provide an undercoat layer of a hydrophilic polymer if necessary, but it is selected depending on the properties of the photosensitive substance provided thereafter.

The support obtained by the present invention can be provided with a photosensitive layer as exemplified below to form a lithographic printing plate.

[I] A case where a photosensitive layer containing a novolak resin of o-naphthoquinonediazidesulfonic acid ester of a polyhydroxy polymer compound and a mixture of phenol and cresol is provided.

As the polyhydroxy polymer compound, those having an average molecular weight of 1,000 to 7000 are used, and have, for example, two or more hydroxy groups on a benzene ring. There is a polycondensate of a phenol compound (eg, resorcinol, pyrogallol, etc.) and an aldehyde compound (eg, formalin, benzaldehyde, etc.). In addition, phenol-formaldehyde resin, cresol-formaldehyde resin, P-tert-
Butylphenol-formaldehyde resin and phenol-modified xylene resin. A more preferred novolak resin is a novolak resin containing phenol having a relatively high molecular weight, and is preferably a phenol-m-cresol-formaldehyde novolak resin disclosed in JP-A-55-57841. Also, in order to form a visible image upon exposure, o-naphthoquinonediazide-4-sulfonyl chloride, an inorganic anion salt of p-diazophenylamine, a trihalomethyloxadiazole compound, a trihalomethyloxadiazole compound having a benzofuran ring, etc. A compound that generates a Lewis acid by the light of the above is added. On the other hand, a triphenylmethane dye such as Victoria Blue BOH, Crystal Violet, or Oil Blue is used as the dye. A photosensitive composition comprising these components is provided in a content of 0.5 to 3.0 g / m ² as a solid content.

[II] A case where a photosensitive layer containing a water-insoluble and lipophilic polymer compound having a diazo resin and a hydroxyl group is provided.

As described above, after providing the anodized film, U.S. Pat.
Immersion in the alkali metal silicate bath disclosed in 81461. A diazo resin PF is applied to the surface treated in this way.
It is preferable to provide the ₆ photosensitive layer containing a water-insoluble and lipophilic polymeric compound having an organic salt and a hydroxyl group of the salt or BF _4, etc. and diazo resins. When such a photosensitive layer is coated on the surface of the support according to the present invention, a photosensitive lithographic printing plate having excellent storage stability and visibility, and particularly stable under severe conditions such as high temperature and high humidity can be obtained.

The diazo resin for this consists of a PF ₆ salt or BF ₄ salt and an organic salt, triisopropyl naphthalene sulfonic acid, 4,
4'-biphenyldisulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 1-naphthol-5-sulfonic acid,
And aromatic sulfonic acids such as p-toluenesulfonic acid;
And hydroxy-containing aromatic sulfonic acids such as -hydroxy-4-methoxybenzophenone-5-sulfonic acid.

The hydroxyl-containing polymer compound has a weight average molecular weight of 50.
For example, (1) a copolymer of N- (4-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) methacrylamide, N- (4-hydroxynaphthyl) methacrylamide and another monomer. (2) copolymer of o-, m-, or p-hydroxystyrene with other monomer; (3) copolymer of o-, m-, or p-hydroxyphenyl methacrylate with other monomer Polymers.

Examples of the monomer include (a) α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and maleic anhydride.

(Ii) Alkyl acrylates such as methyl acrylate and ethyl acrylate.

(C) Alkyl methacrylates such as methyl methacrylate and ethyl methacrylate.

(D) Acrylamide or methacrylamides such as acrylamide and methacrylamide.

(E) Vinyl esters such as ethyl vinyl ether and hydroxyethyl vinyl ether.

(F) Styrenes such as styrene and α-methylstyrene.

(G) Vinyl ketones such as methyl vinyl ketone.

(H) Olefins such as ethylene, propylene and isoprene.

(Ii) N-vinylpyrrolidone, N-vinylcarbazole, acrylonitrile, methacrylonitrile, and the like, and any other monomer that can be copolymerized with a monomer containing an aromatic hydroxyl group.

The oil-soluble dye added to the photosensitive layer is Victoria Pure Blue BOH, Crystal Violet, Victoria Blue, Methyl Violet, Oil Blue # 603.
Are preferred. To form a photosensitive layer having these compositions,
Fluorinated surfactants, nonionic surfactants, plasticizers (eg, dibutyl phthalate, polyethylene glycol, diethyl phthalate, trioctyl phosphate, etc.) and known stabilizers (eg, phosphoric acid, phosphorous acid, organic acids) Etc., so that the coating weight after drying is 0.5 to 2.5 g / m ² .

[III] A case where a photosensitive layer comprising a photopolymerizable photosensitive composition containing a polymer having a carboxylic acid residue or a carboxylic anhydride residue, an addition polymerizable unsaturated compound and a photopolymerization initiator is provided.

In the case of a photopolymerizable photosensitive material, the surface of the support grained with a hydrochloric acid bath is preferably anodized with phosphoric acid or a mixed acid of phosphoric acid and sulfuric acid.

After anodic oxidation in a phosphoric acid bath and silicate treatment, a polymer having a carboxylic acid residue or a carboxylic anhydride residue,
A layer of a photopolymerizable photosensitive composition containing an addition polymerizable unsaturated compound and a photopolymerization initiator is provided. Also, JP-A-1007042
Can be used for a lithographic printing plate using an electrophotographic photoreceptor as disclosed in Japanese Patent Application Laid-Open Publication No. H10-209,878.

The printing plate thus formed has good storability, and the exposed aluminum plate surface in the non-image area is hardly stained with printing ink, and has good hydrophilicity for quickly removing the stained ink. And has high adhesive strength to the photosensitive layer.

Polymers having a carboxylic acid residue or a carboxylic anhydride residue suitable for this purpose include the following [A] to [D]
A polymer having a structural unit selected from the following is preferable.

(Wherein R ₁ and R ₄ are a hydrogen atom or an alkyl group, R ₃
Is an alkylene group which may have a phenylene group or a hydroxy group, R ₅ is a hydrogen atom, an alkyl group which may have a substituent, R ₆ is an alkyl group which may have a substituent, allyl Group moshi represents an aryl group or a cycloalkyl group, and n represents 0 or 1.) As more specific structural units, acrylic acid, methacrylic acid, crotonic acid, vinylbenzoic acid, etc. may be mentioned as formula (A). Formula (B) includes maleic acid, maleic acid monohydroxyalkyl ester, maleic acid monocyclohexyl ester, and the like, and Formula (C) includes maleic acid monoalkylamide, maleic acid monohydroxyalkylamide, and the like. Examples of (D) include maleic anhydride, itaconic anhydride and the like. As the polymer, those having an average molecular weight of 1,000 to 100,000 are usually used.

The addition-polymerizable unsaturated compound has an ethylenically unsaturated double bond such that when the photopolymerizable photosensitive resin composition is irradiated with actinic rays, it undergoes addition polymerization in three-dimensional directions mutually and causes insolubilization. It is a monomer. Examples thereof include unsaturated carboxylic acids, esters of unsaturated carboxylic acids and aliphatic polyhydroxy compounds, and esters of unsaturated carboxylic acids and aromatic polyhydroxy compounds.

As the photopolymerization initiator, benzoin, benzoin alkyl ether, benzophenone, anthraquinone, Michler's ketone or the like can be used alone or in combination.
It is provided so that the coating amount after drying is 33 g / m ² .

 A lithographic printing plate is created as described above.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples.

Example 1 The alloys No. 1 to No. 13 shown in Table 1 were melted and cast, and both surfaces were chamfered to form an ingot having a thickness of 500 mm, a width of 1000 mm and a length of 3500 mm. After performing hot-rolling by heating to 400 ° C, performing cold rolling, performing intermediate annealing at 450 ° C (without holding) in a continuous annealing furnace, and then reducing the sheet thickness by 80%. Finish cold rolling was performed to obtain an alloy plate having a thickness of 0.30 mm.

The mechanical properties of the alloy sheets thus obtained were examined.

Next, after the surface of the alloy plate having a thickness of 0.30 mm was chemically etched with a 10% aqueous sodium hydroxide solution,
The solution was neutralized and washed in 20% nitric acid at a temperature of 20 ° C., and subjected to alternating current electrolysis with a 1% nitric acid electrolyte at a current density of 30 A / m ² at 50 ° C. for 10 seconds.

Subsequently, the surface was cleaned by immersing it in a 50% aqueous solution of 15% sulfuric acid for 3 minutes, and then an oxide film of 3 g / dm ² was provided in an electrode solution containing 20% sulfuric acid at a bath temperature of 30 ° C.

The samples prepared in this manner were provided with the following photosensitive layers so that the coating amount upon drying was 2.5 g / m ² .

Ester compound of naphthoquinone (1,2) -diazide- (2) -5-sulfonic acid chloride and resorcin-benzaldehyde resin 1 part by weight Phenol and m-, p-mixed cresol and formaldehyde copolymerized and condensed resin 3.5 parts by weight 2- Trichloromethyl-5- [β- (2'-benzofuryl) vinyl] -1,3,4-oxadiazole 0.03 parts by weight Victoria Pure Blue BOH (manufactured by Hodogaya Chemical) 0.1 part by weight o- of p-butylphenol benzaldehyde novolak resin Naphthoquinonediazide sulfonic acid ester 0.05 parts by weight Methyl cellosolve 27 parts by weight Using a 3 kW metal halide lamp,
It was exposed for 0 second, developed with a 4% aqueous solution of sodium metasilicate at 25 ° C. for 45 seconds, washed with water and dried, and gummed to obtain a lithographic printing plate.

These printing plates were mounted on an offset printing machine KOR, and stains (ink stains) in the drawn image area and printing durability were examined. The pit pattern produced by electrochemical surface roughening is measured using an electron microscope (SE
M) The surface was observed.

 Table 2 shows the above results.

In the case of the present invention examples Nos. 1 to 4, the tensile strength is as high as 14 kgf / mm ² or more, the pit pattern is fine and good in a circular shape, the number of printed sheets is as large as 90 to 100,000, and the printing durability is good. , Less ink stain.

Comparative Example No. 5 has a small amount of Fe, so the strength is low, the pit pattern is slightly poor, and the number of printed sheets is small. No. 6 is Fe
The pit pattern is defective due to the large number of prints, and the number of printed sheets is small. No. 7 has low strength due to low Si, the pit pattern is slightly poor, and the number of printed sheets is small. No. 8 has a lot of ink stains because it has a lot of Si. No. 9 has a small number of printed sheets due to a small amount of Cu. No. 10 has a poor pit pattern due to a large amount of Cu, and the number of printed sheets is small. No. 11 is [Ti
(%)] <1.2 × [Ga (%)] − 0.015, the pit pattern is slightly defective, and the number of printed sheets is small. No.12
The pit pattern is slightly defective due to a large amount of Ti, and the number of printed sheets is small. No. 13 also has a poor pit pattern due to a large amount of Ga, and has few printed sheets.

Example 2 Next, in order to clarify the effects of the amounts of Ti and Ga, the alloys of Nos. 14 to 32 shown in Table 3 were melted and cast, and both surfaces were chamfered to a thickness of 500 mm and a width of 1000 mm. 3500mm length ingot, subjected to homogenization at 580 ℃, heated to 410 ℃ and then hot-rolled, then cold-rolled, by continuous annealing furnace
After intermediate annealing at 480 ° C. (no holding time), finish cold rolling was performed at a sheet thickness reduction rate of% to obtain an alloy sheet having a thickness of 0.30 mm.

The alloy plate thus obtained was examined for mechanical properties, pit patterns, number of printed sheets (printing durability), and ink stains in exactly the same manner as in Example 1. The results are shown in Table 4.

In the case of the present invention examples Nos. 14 to 25, the strength is high, the pit pattern is good, the number of printed sheets is large, and the ink stain is small. In the case of Comparative Examples Nos. 26 to 32, since [Ti (%)] <1.2 × [Ga (%)] − 0.015, the pit pattern was slightly poor to poor,
The number of prints is small.

The pit patterns of No. 2 and No. 11 of Example 1 and No. 29 of Example 2 are shown in FIG. 1 (1500 times magnification). In the case of No. 2, the pits are fine and circular. In the case of No. 11, the pits are distorted and slightly crescent-shaped, and in the case of No. 29, the pits are significantly distorted.

Next, Nos. 1 to 4 and Nos. 11 to 13 of Example 1 and N of Example 2
From the results of o.14 to 32, the relationship between the pit patterns of the Ti amount and the Ga amount is shown in FIG. A region having a good pit pattern is represented by the following equation.

[Ti (%)] ≦ 0.10 [Ga (%)] ≦ 0.04 [Ti (%)] ≧ 1.2 × [Ga (%)] − 0.015 Example 3 Next, in order to see the influence of the manufacturing conditions, Example 1 was used. No.1 ~
As shown in Table 5, the alloy No. 4 was prepared by changing the homogenizing treatment temperature, the hot rolling heating temperature, the method of intermediate annealing (continuous furnace or batch furnace), and the thickness reduction rate of the finish cold rolling to 0.30 mm.
An alloy plate having a thickness was obtained. Then, in the same manner as in Example 1, the mechanical properties, the pit pattern, the number of printed sheets (printing durability), and the ink stain were examined. Here, streak on the surface when a lithographic printing plate was prepared was also observed. The results are shown in Table 6.

In the case of No. 1A, 2A, 3A, 4A, 1E, 2E, 3E, 4E, the strength is high, the pit pattern is good, the number of printed sheets is large,
Good streak and less ink stain. No.1B, 2
In the case of B, 3B, and 4B, ink stains are slightly more due to the high homogenization treatment temperature. In the case of Nos. 1C, 2C, 3C, and 4C, the pits were slightly distorted due to the low homogenization processing temperature, and the number of printed sheets was slightly small. In the case of Nos. 1D, 2D, 3D, and 4D, streaks due to streak-like non-uniform structures occurred because the heating temperature of hot rolling was high. In the case of Nos. 1F, 2F, 3F and 4F, the strength is low due to the low reduction rate of the thickness of the finish cold rolling.

As described above, it is desirable that the homogenization treatment temperature is 450 to 600 ° C., the heating temperature of hot rolling is 350 to 600 ° C., and the reduction rate of the thickness of finish cold rolling is 50% or more. The intermediate annealing may be performed in a batch furnace or a continuous furnace. Each optimum condition is as described above.

[Effects of the Invention] The present invention is configured as described above, and therefore, the aluminum alloy support for a lithographic printing plate has sufficient strength to hardly cause plate cracking, and pits due to electrochemical graining are reduced. Since it is finely uniform, it has excellent printing durability and also has a remarkable effect of being excellent in stain resistance.

[Brief description of the drawings]

FIGS. 1 (a), (b) and (c) are electron micrographs showing the metal surface structures of Examples Nos. 2, 11 and 29, and FIG. 2 is a graph showing the relationship between the pit pattern and the amount of Ti and Ga. Show.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigenori Yamauchi 3-1-112 Minato-ku, Minato-ku, Nagoya-shi, Aichi Prefecture Sumitomo Metal Industries Co., Ltd. Technical Research Institute (72) Inventor Yuji Suzuki 3-year-old Minato-ku, Nagoya-shi, Aichi No. 1-112, Sumitomo Metal Industries, Ltd.Technical Research Laboratory (72) Inventor Shin Nobuchida 3-1-1-12, Minato-ku, Nagoya-shi, Aichi Prefecture Sumitomo Metal Industry Co., Ltd.Technical Research Laboratory (56) References JP-A-60 JP-A-215725 (JP, A) JP-A-62-148295 (JP, A) JP-A-58-130242 (JP, A)

Claims (1)

(57) [Claims] 1. Fe: 0.1-1.0% (% by weight, the same applies hereinafter), Si:
0.03-0.2%, Cu: 0.005-0.05%, Ti: 0.1% or less, Ga: 0.
Less than 04%, remaining Al and unavoidable impurities, Ti
The relationship with Ga is [Ti (%)] ≧ 1.2 × [Ga (%)] − 0.0
An aluminum alloy material for a lithographic printing plate, which is 15.