JPH0678036B2 - Aluminum alloy support for lithographic printing plates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION “Object of the Invention” The present invention relates to the creation of an aluminum alloy support for a lithographic printing plate, which has a suitable surface roughening property and printability while maintaining the strength of the support and the resistance of non-image areas. It is intended to provide an aluminum alloy support for a lithographic printing plate which has excellent abrasion resistance and high printing durability.

Industrial field An aluminum alloy support for lithographic printing plates that possesses both surface roughening properties and printability, as well as excellent strength and abrasion resistance in non-image areas.

2. Description of the Related Art Aluminum alloy substrates for offset printing have been known for some time. That is, in general, aluminum and aluminum alloys are lightweight, have excellent workability, and have good surface treatment properties, and therefore are suitable as a support for offset printing, and particularly JIS 10
50 (Purity 99.5% or higher Al), JIS 1100 (Purity 99.0% or higher Al), JIS 3003 (Al-0.05 to 0.2% Cu-1.0 to 1.5% Mn
Aluminum or aluminum alloy (hereinafter simply referred to as aluminum alloy) such as alloy) is widely adopted.

After these aluminum alloys are made into a plate, the surface thereof is roughened and anodized by a step of combining one or more of a mechanical method, a chemical method and an electrochemical method, and then Then, a photosensitive composition (generally a photosensitive resin) is applied to the plate surface, dried, and processed into a so-called PS plate. Then, the PS plate is subjected to a plate-making process such as image exposure, development, washing with water and gumming to produce a printing original plate.By this image exposure, subsequent development is performed between the exposed portion and the unexposed portion of the photosensitive resin layer. In the treatment, a difference in solubility in a developing solution occurs, and one of the exposed portion and the unexposed portion is dissolved or removed in the developing solution by the developing treatment, and the other remains on the aluminum plate as a support. Form an image. The image portion exhibits ink receptivity, and the non-image portion in which the photosensitive resin is dissolved and removed as described above exhibits water receptivity by exposing the surface of the hydrophilic aluminum support.

Next, both ends of the above printing original plate are bent to form a gripping portion into the printing machine, fixed to the cylindrical plate cylinder of the printing machine, and dampening water (water or aqueous solution) is supplied to the plate surface. Hold the film of dampening water in the non-image area, while supplying ink to the image area, and directly or indirectly transfer the ink attached to the image area to the blanket cylinder and then transfer it to the paper surface. Printing is performed by repeating the process of performing. In this printing, by appropriately selecting the photosensitive composition coated on the support, it is possible to obtain a good printed matter, which generally reaches up to 100,000 sheets. There is a strong desire to improve printing durability.

However, as the printing speed has increased in recent years, the printing speed has increased, and the stress applied to the printing plates mechanically fixed to both ends of the printing press plate cylinder has increased. When the body strength is insufficient, the fixed portion is deformed or damaged to cause an obstacle such as print misalignment, and thus the improvement of the strength of the support is indispensable.

On the other hand, as one means for improving the printing resistance, in the case of a lithographic printing plate using aluminum as a support, the image portion after exposure and development is subjected to anodizing treatment after roughening as described above to form an image portion after exposure and development. On the other hand, a method of improving the adhesiveness with the photosensitive composition and the hydrophilicity with respect to the non-image portion is generally performed. And the anodizing process is sulfuric acid, phosphoric acid,
Anodizing is usually performed at about 3 g / m ^{2 on the} surface of an aluminum support by applying a direct current or an alternating current to aluminum in an aqueous solution or a non-aqueous solution containing chromic acid or the like or a mixture of two or more of these. A film is formed. However, since the non-image area during printing is in direct contact with the paper or blanket cylinder, it gradually wears off and impairs the specified printing plate performance.Therefore, especially when the number of prints is large, the non-image area has excellent abrasion resistance. Is required.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, the above-described conventionally used aluminum alloy plates cannot adequately and promptly meet the above-mentioned requirements. That is, pure aluminum alloys such as JIS 1050
The electrochemical roughening treatment gives a uniform rough surface and appropriate surface roughness, and the printing performance is also excellent, but the support strength is insufficient and the non-image area is abraded when the number of prints is large. There are cases. In addition, JIS 3003 has an appropriate support strength, but electrochemical surface treatment does not provide a uniform rough surface or appropriate surface roughness, and it is also liable to stain non-image areas during printing. Have. However, in order to improve the wear resistance of the non-image portion, if a thicker anodic oxide coating than the conventional one is formed on the surface of the aluminum alloy support, the appropriate surface roughness formed during roughening must be impaired. I don't get it.

From the above viewpoints, the present invention has excellent electrochemical roughening properties and printability of pure aluminum alloys,
An object of the present invention is to provide a support for a lithographic printing plate which is excellent in strength and abrasion resistance of a non-image portion.

"Structure of the Invention" Means for Solving Problems A slab of aluminum alloy is rolled to a required thickness, solution-treated, rapidly cooled, and further cold worked to obtain a surface Vickers hardness.
A plate-shaped body of HmV75-110, the surface of which is roughened and anodized, which contains Si: 0.85-2 wt% and the balance being Al and unavoidable impurities. Aluminum alloy support.

Action The most characteristic component of the aluminum alloy support in the present invention is Si, and the content thereof is 0.85 to 2 wt%. Si
Is contained in such a range, in the plate making step, a part of the contained Si is brought into a solid solution state and the remaining Si is appropriately dispersed and produced as the second phase particles, and the ingot is formed into 10
By hot-rolling or cold-rolling to 1/0 or less to sufficiently thin the plate, good roughening property can be obtained, and further strength required for the support can be obtained.

Further, since the surface Vickers hardness is HmV75 to 110, the non-image when used as a support for lithographic printing in combination with the second phase particles of Si dispersed and generated in the support as described above. Improves wear resistance of parts. In addition, the surface of the support is roughened and then anodized, and the above-mentioned second
The presence of phase Si particles effectively improves wear resistance and enhances printing durability.

When the Si content is less than 0.85 wt%, the above-mentioned dispersion formation of the second phase particles is insufficient, and the surface Vickers hardness HmV7
If it is less than 5, the abrasion resistance of the support itself or the effect of retaining the second phase particles is small and the printing durability is insufficient. If the surface Vickers hardness is more than HmV110, it becomes difficult to fit to the plate cylinder when the plate cylinder is fixed, which causes printing misalignment. Further, if Si exceeds 2 wt%, the surface roughening property is deteriorated. The support according to the present invention is made of Si
By setting the content to 0.85 wt% or more and 2 wt% or less and the surface Vickers hardness to HmV75 to 110, the effects of the present invention can be effectively exhibited.

The other components are all at the impurity level including Mg and Ca. For example, when the content of Mg exceeds 0.3% or more as the second phase particles, 0.1 to 2 as the second phase particles is contained.
It is difficult to obtain preferable printing durability since particles such as Mg ₂ Si particles having a size of μm are generated, and they become a starting point of melting loss during chemical etching. When the components other than Si are equal to or less than the unavoidable impurity level with Al, the above-mentioned working relationship is not impeded.

Examples To further explain the present invention as described above, as a result of various researches by the present inventors based on the above-mentioned circumstances, an aluminum alloy plate containing a proper amount of Si in aluminum is electrochemically roughened. , Which has excellent printability and printability, and has an excellent support strength, was further investigated, and when the surface hardness was above a certain level, the lithographic printing was carried out in combination with the Si particles present in the plate. It was found that when used as a support for use, the wear resistance of the non-image part is also improved,
The present invention has been completed.

That is, the present invention, the aluminum alloy ingot is rolled to a required thickness, solution treatment, quenching, further cold-worked surface Vickers hardness is a plate-shaped body of HmV75 ~ 110, the surface is rough. An aluminum alloy support for a lithographic printing plate, which is surfaced and anodized, contains Si: 0.85 to 2 wt% and the balance is Al and inevitable impurities.

Fe and Mn contained in the support of the present invention are each up to 0.4 wt%, M
The content of less than 0.3 wt% of g and up to 0.05 wt% of Cu and Cr does not hinder the characteristics of the support of the present invention as unavoidable impurities. In order to refine the ingot crystal, Ti
And B may be added, but in this case, if Ti—B-based particles aggregate, linear defects are likely to occur during the roughening treatment, so Ti: 0.05 wt% or less, B: 0.01 wt% or less. .

The plate making process of the aluminum alloy support for lithographic printing and the plate making process as a PS plate having the above composition will be described below. That is, the molten alloy of the above composition is cast by a usual method, in this case, the solidification rate of the molten metal is increased by reducing the thickness of the casting slab,
It is more preferable to refine the crystallized Si particles, and from the same viewpoint, the thin plate may be manufactured by performing thin plate continuous casting in which the thin plate is directly cast from the molten metal. Next, after the obtained cast slab is chamfered, it is kept at a temperature of 400 to 560 ° C. for 1 hour or more for homogenization treatment. Further, after the steps of hot rolling and example rolling, solution treatment is performed to obtain a recrystallized structure and to form a solid solution of a predetermined amount of Si in the matrix. Specifically, for example, 400 ° C. or higher in a continuous annealing device, preferably 450
After heating to a temperature of ~ 560 ℃, 30 ℃ / mi after reaching this specified temperature
Air cooling is performed at a cooling rate of n or more, and rapid cooling is preferably performed by water cooling. Then, final cold rolling with a working rate of 30% or more, preferably 40% or more is performed to form a plate-like material having a thickness of 0.1 to 0.5 mm, which is an aluminum alloy plate for a lithographic printing plate support. In addition, it is more effective from the viewpoint of improving the electrochemical roughening property and the surface hardness to perform the tempering treatment in which the heat treatment is performed for 2 hours or less as a guide at the temperature of 50 to 250 ° C. after the final cold rolling. Target. Si existing in the processed structure under any manufacturing conditions
Is desired to be a solid solution state or to be uniformly dispersed as Si particles, whereby a predetermined support strength and surface hardness can be obtained and the uniformity of grain in the roughening treatment can be secured.

The aluminum alloy plate thus produced is subjected to an actual printing operation through a PS plate processing and a plate manufacturing processing. That is, in the case of being used after being subjected to a surface roughening treatment, first, a surface roughening treatment by a mechanical graining method or an electrochemical graining method in an electrolytic solution containing nitric acid or hydrochloric acid is carried out, followed by acid treatment. Alternatively, it is subjected to chemical etching treatment with alkali and desmutting treatment by pickling. Further, if necessary, an oxide film formation treatment by anodizing treatment or chemical conversion treatment,
An undercoat layer forming treatment such as an alkali metal silicate or hydrophilic cellulose is performed thereon. Subsequently, a PS plate is obtained by applying an appropriate photosensitive composition, drying and cutting into a desired size. A desired image is exposed on this PS plate, and plate-making processing such as development, washing with water, and gumming is performed. The plate-made printing original plate is further bent at both ends thereof to form a holding portion for the printing machine, and then fixed to a cylindrical plate cylinder of the printing machine to be subjected to a printing operation.

The aluminum alloy support according to the present invention has less deformation during plate mounting in this printing operation, less abrasion of the non-image area during printing, and has good surface roughening property, and is particularly remarkably useful as a lithographic printing plate support. It achieves high printing durability. In addition, since the heat dissipation is good, the ink paste is good,
Moreover, it does not deteriorate the properties of the ink.

The following is a detailed description of a specific manufacturing example of the device according to the present invention.

Production Example 1 Three types of aluminum alloys (A,
B and C) are melted and filtered using a microporous filter, then a slab with a thickness of 406 mm is obtained by DC casting, subjected to homogenization treatment at 560 ° C. for 4 hours, and then hot rolled to a thickness of 6 mm. Rolled, then inter-rolled, 1.5 mm for alloys A and B
For alloy C, 0.6 mm thick (intermediate annealing was performed in the middle), and then magnetic induction heating (Transverse FluxI
5 at a heating rate of 150 ℃ / sec or more
After being kept at 50 ° C for 5 seconds, subjected to continuous solution treatment by water cooling at 500 ° C / sec or more, allowed to stand at room temperature for about 1 day, and then subjected to final cold rolling as shown in Table 2 below, Alternatively, after this final cold rolling, tempering treatment was combined to obtain an alloy plate having a thickness of 0.3 mm. As a conventional material, commercially available JIS 1050-H1
8 and JIS 3003-H18 0.3 mm thick plates were used as test materials.

Tensile properties and surface hardness of each of the aluminum plates obtained as described above were measured by a conventional method. On the other hand, the eight kinds of alloy plates shown in Table 2 were treated as a printing support. That is, these aluminum alloy plates were grained with a rotating nylon brush in a suspension of pumice and water, chemically etched with a 20 wt% aqueous solution of caustic soda, then washed with water and acidified with a 25 wt% nitric acid aqueous solution. After washing and washing with water again, an alternating current electric field is applied at a current density of 20 A / dm ² or more in an electric field bath containing 0.5 to 2.5 wt% nitric acid, and then immersed in a 50 wt% aqueous solution of 15 wt% sulfuric acid for 3 minutes. After cleaning the surface, bath temperature in an electrolyte solution containing 20 wt% sulfuric acid as the main component
Anodization treatment was performed at 30 ° C. to provide an oxide film of 3 g / m ² .

Performing SEM observation of the surface for the roughening property of the support obtained as described above, and to evaluate the uniformity of the sand,
The results of examining the dispersion state of the Si particles existing on the roughened surface are as shown in Table 2.

The results of mechanical properties, surface hardness and roughness uniformity are shown in Table 2 above. The mechanical properties were all measured in the direction parallel to the rolling direction (L direction). In other words, the alloys A and B-1 to 3 of the present invention are significantly superior in support strength (0.2% proof stress) and surface Vickers hardness (HmV) to the high level of conventional materials, and have a roughening property. Is equivalent to or better than that, and the printing durability is 300,000 times. In addition, Si particles are observed on the surface of the support. For example, in alloy B-1, the average diameter is about 15 μm.
The following particles were present in an amount of about 1 × 10 ² particles / mm ^{2, and} about 2 × 10 ⁶ particles / m ² in Alloy B-2. C-1 has good uniformity of the rough surface, but the surface hardness (HmV) does not reach the level of the present invention, and therefore wear resistance and printing durability are not sufficient. Comparative material C-2 is slightly inferior in the uniformity of the rough surface and inferior in the surface hardness, so that the abrasion resistance and the printing durability are further inferior. Moreover, JIS 1050-H18, which is a conventional material, has good uniformity of the rough surface, but the support strength and surface hardness remain at a low level, and JIS 3003-H18 is excellent in support strength and surface hardness. However, the roughening property is inferior.

Production Example 2 Inventive material B-2 obtained in Production Example 1 and comparative material C-
2 and the conventional material JIS 1050-H18 were further subjected to plate-making processing as a printing plate and evaluated as a printing plate. That is, the following photosensitive layer was formed on a support manufactured by the same method as described in Production Example 1 so that the coating amount when dried was 2.5 g / m ² .

Compound of naphthoquinone-1,2-diaside-5-sulfonyl chloride and pyrogallolacetone resin (described in US Pat. No. 365709, Examples) 0.75 g Cresol novolac resin 2.00 g Oil blue +603 (Orient Chemical Co., Ltd. 0.04g Ethylene dichloride 16g 2-Methoxyethylene acetate 12g The resulting photosensitive lithographic printing plate was brought into close contact with a transparent positive image and PS light (Toshiba Metal Halide Lamp MU2002-
2-OL type, having a light source of 3 KW) for 30 seconds, then immersed in a 5 wt% aqueous solution of calculated sodium for about 1 minute for development, washed with water and dried to obtain a printing original plate.

When these printing original plates were mounted on an offset printing machine KOR and a printing test was conducted using an ink containing an inorganic pigment CaCO ₃ and the contact pressure with the blanket cylinder was higher than usual, 300,000 copies were printed for Invention Material B-2. Even after the completion, the non-image area of the printing original plate was not worn and a good printed matter was obtained. On the other hand, in the printing original plate using the comparative material C-2 and the conventional material JIS 1050-H18, C-2 was used for 250,000 copies, and JIS 1050-H18 was printed for 150,000 copies. Was occurring.

"Effects of the Invention" When the aluminum alloy support for lithographic printing plates of the present invention as described above is used, it is sufficiently excellent in surface roughening property and printability as compared with the comparative material and the conventional material, and the support Since it is extremely excellent in strength and surface hardness, it is possible to appropriately eliminate troubles due to deformation during plate mounting and abrasion phenomenon of non-image area during printing, and it is possible to provide products with high printing durability. It is an invention that has a great effect industrially.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Issei Takizawa 4000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Fuji Shashin Film Co., Ltd. (72) Inventor ▲ Sakaki ▼ Hirokazu Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Fuji Shashin Film Co., Ltd. (56) Reference JP-A-59-220395 (JP, A) JP-A-57-173196 (JP, A) JP-A-56-53095 (JP, A) JP-B 32-32 9752 (JP, B1)

Claims (1)

[Claims] 1. A plate-shaped body having a surface Vickers hardness of HmV75 to 110, which is obtained by rolling an aluminum alloy ingot to a required thickness, subjecting it to solution treatment, quenching, and further cold working, and having a rough surface. An aluminum alloy support for a lithographic printing plate, which is surfaced and anodized, contains Si: 0.85 to 2 wt% and the balance is Al and inevitable impurities.