JP4318587B2 - Aluminum alloy plate for lithographic printing plates - Google Patents

Description

The present invention, aluminum alloy strip for lithographic printing plates, in particular, it is possible to uniformly roughen the surface by electrochemical etching treatment, excellent strength and heat softening the aluminum alloy strip for lithographic printing plates which includes About.

  In general, an aluminum alloy plate is used as a support for lithographic printing plates (including offset printing plates), and the support is rough from the viewpoint of improving the adhesion of the photosensitive film and improving the water retention of the non-image area. Processing is performed.

  Conventionally, as the surface roughening method, mechanical surface roughening methods such as ball graining, brush graining and wire graining have been performed. As a support, JIS A1100 (aluminum purity 99.0%) has been used so far. ), A3003 (aluminum purity 98.0-98.5%), etc. were used.

  In recent years, rapid progress has been made in the technique of roughening the surface of aluminum alloy plates for supports by electrochemical etching because of their excellent platemaking and printing performance and the ability to continuously process with coil materials. is doing. The electrochemical etching treatment uses an electrolytic solution mainly composed of hydrochloric acid or hydrochloric acid (hereinafter referred to as a hydrochloric acid-based electrolytic solution) or an electrolytic solution mainly composed of nitric acid or nitric acid (hereinafter referred to as a nitric acid-based electrolytic solution). A material equivalent to A1050 (aluminum purity 99.5%), which can obtain a relatively uniform electrolytic surface roughening, is applied as a support, and 10 can be obtained by appropriately selecting a photosensitive layer coated on the support. It is possible to obtain tens of thousands of clear printed materials.

  Further, in order to improve the printing durability of the printing plate, the printing plate having an aluminum alloy plate as a support is exposed and developed by a usual method, and then heated at a high temperature (referred to as a burning treatment) to obtain an image area. Strengthening has been done. Since the burning treatment is usually performed under the conditions of a heating temperature of 200 to 290 ° C. and a heating time of 3 to 9 minutes, heat resistance (burning resistance) that does not lower the strength of the support during the burning treatment is necessary. It becomes.

  In addition, recently, with the advance of printing technology, the printing speed has increased and the strength against the support has increased in response to the increased stress applied to the printing plates that are mechanically fixed to both sides of the printing press cylinder. When the demand is increasing and the support strength is insufficient, the fixed portion is deformed or damaged, resulting in troubles such as printing misalignment. Therefore, it is indispensable to improve the strength of the support along with the above-mentioned burning resistance. .

  In order to satisfy such requirements, specifically, an attempt has been made to use a support in which Mg and Zn are added based on an A1050 equivalent material. As what added Mg, Fe: 0.30-0.40%, Si: 0.05-0.25%, Cu: 0.04% or less, Mn: 0.05% or less, Mg0.10- Aluminum alloy support added with 0.30% (see Patent Document 1), Mg: 0.05 to 0.3%, Si: 0.02 to 0.3%, Fe: 0.1 to 0.4% Cu: 0.05% or less of an aluminum alloy support (see Patent Document 2), Fe: 0.05 to 0.5%, Mg: 0.1 to 0.9%, V and Ni Aluminum alloy support added with at least one of 0.01 to 0.3%, Si: 0.2% or less, Cu: 0.05% or less (see Patent Document 3), Mg: 0.005 to 0.00. 2%, Cu: 0.3% or less, Mn: 1.5% or less, Cr: 0.3% or less, Fe: 1.0% or less, i: Aluminum alloy support added with one or more of 1.0% or less (see Patent Document 4), Si: 0.05 to 0.7%, Mg: 0.05 to 3%, Zr: An aluminum alloy support added with 0.01 to 0.25% (see Patent Document 5) has been proposed.

As for what Zn is added, Fe: 0.25 to 0.6%, Si: 0.03 to 0.1%, Cu: 0.05% or less, Ti: 0.05% or less, Zn: 0. Aluminum alloy support containing 01 to 0.10% and (Zn% / 2) + Ti% −Cu% ≧ 0.003% (see Patent Document 6), Fe: 0.20 to 0.6%, Aluminum alloy support containing Si: 0.03 to 0.1%, Zn: 0.04 to 0.1% and Zn% / Fe% ≧ 0.2% (see Patent Document 7), Fe: 0.11 to 0.60%, Si: 0.01 to 0.20%, Ni: 0.005 to 0.075%, Zn: 0.005 to 0.075%, Cu: less than 0.05% And an aluminum alloy support containing Zn% ≦ 0.08−Ni% and Fe% ≧ 0.1 + Si% (see Patent Document 8), Fe: 0.05-0.5%, Si: 0.02-0.2%, Cu: 0.001-0.05%, Ti: 0.003-0.04%, Mg: 0.001-0.3 %, Mn: 0.001 to 0.05%, Zn: 0.001 to 0.05%, a lithographic printing plate support (see Patent Document 9) made of an aluminum alloy plate has been proposed.
JP 2001-49373 A (Claims) JP 61-146598 A (Claims) JP-A-62-230946 (Claims) JP 59-93850 (Claims) JP 62-74693 A (claim) JP-A-8-311592 (Claims) JP-A-9-316582 (Claims) Japanese Patent Laid-Open No. 2001-211962 (Claims) JP 2002-363799 A (Claims)

  However, the above-mentioned aluminum alloy plate for a support satisfies all the requirements for formation of uniform roughened pits, high strength, and burning resistance in an electrolytic surface roughening treatment using a hydrochloric acid electrolyte or a nitric acid electrolyte. In other words, it does not necessarily have sufficient characteristics to meet strict demands on the adhesion of the photosensitive film and the water retention of the non-image area.

  The inventors can meet the strict requirements for adhesion of the photosensitive film to the printing plate and water retention of the non-image area, further improve the uniformity of the roughened pits, and meet the requirements for high strength and burning resistance. In order to obtain an aluminum alloy plate for a printing plate support that can be used, the content of the components in the aluminum alloy support based on the A1050 equivalent material, the relationship between the components and the above-mentioned characteristics are further diversified. As a result of a specific study, it was found that a specific amount of Mg and Zn were allowed to coexist, whereby the strength and heat resistance were improved, and excellent roughening characteristics were obtained.

  The present invention has been made on the basis of the above-mentioned knowledge, and the object thereof is to form extremely uniform pits on the surface by electrochemical surface roughening treatment, and to achieve better adhesion and water retention with a photosensitive film. Is to provide an aluminum alloy plate for a lithographic printing plate having excellent strength and burning resistance.

  In order to achieve the above object, an aluminum alloy plate for a lithographic printing plate according to claim 1 of the present invention comprises Mg: 0.1 to 0.3%, Zn: more than 0.05% and 0.5% or less, Fe : 0.2 to 0.6%, Si: 0.03 to 0.15%, Cu: 0.02% or less, Ti: 0.003 to 0.05%, balance Al and impurities It is characterized by.

An aluminum alloy plate for a lithographic printing plate according to claim 2 is characterized in that, in claim 1, the Mg content and the Zn content satisfy a relationship of 0.4 × Zn% ≦ Mg% ≦ 4 × Zn%. Features.

  According to the present invention, uniform pits are formed by the electrochemical surface-roughening treatment, and further excellent adhesion and water retention with the photosensitive film are obtained, and further improved image sharpness and printing durability are obtained. An aluminum alloy plate for a lithographic printing plate that can be achieved and is excellent in strength and heat softening resistance is provided.

  The significance and reasons for limitation of the components contained in the aluminum alloy plate for lithographic printing plates of the present invention will be described.

  Most of Mg functions as a solid solution in aluminum to improve strength and heat softening resistance. The strength is the tensile strength at room temperature as a printing plate support, and 160 MPa or more is a practically preferable range. Heat softening resistance, also called burning resistance, is 0.2% proof stress after being heated at a temperature of about 280 ° C., and 90 MPa or more is a practically desirable range. The preferable content of Mg is in the range of 0.1 to 0.3%. If the content is less than 0.1%, the effect is not sufficient. If the content exceeds 0.3%, the uniformity of pits in the surface roughening treatment is insufficient. The non-image area is liable to be deteriorated.

  Zn, like Mg, is mostly dissolved in aluminum, but does not function to improve strength and heat softening properties like Mg, and affects the oxide film formed on the aluminum surface. The oxide film formed on the aluminum surface includes an oxide film formed when left at room temperature (natural oxide film) and an oxide film formed during heat treatment in the manufacturing process, but Zn affects both. give.

  That is, in an aluminum alloy containing Mg, an oxide film mainly composed of Mg oxide (MgO-based oxide) is easily formed by heat treatment such as homogenization treatment, heating during hot rolling, and intermediate annealing. Since the oxide film is active and porous, the wettability with the treatment liquid is improved in the electrolytic surface-roughening treatment and the surface roughening is promoted, but the pits are likely to be non-uniform. The inclusion of Zn improves the unevenness of the roughened structure and functions to suppress activation by Mg oxide. The preferable content of Zn is in the range of more than 0.05% and less than 0.5%. The effect is small if it is less than 0.05%, and if it exceeds 0.5%, the activation suppression by Mg oxide is suppressed. The effect becomes large and the roughening becomes non-uniform, and a coarse intermetallic compound is easily generated, and coarse pits are formed during the electrolytic treatment, and the roughening becomes further non-uniform. A more preferable content range of Zn is 0.06 to 0.5%.

  It is desirable that the Mg content and the Zn content satisfy the relationship of 0.4 × Zn% ≦ Mg% ≦ 4 × Zn%, and when 0.4 × Zn%> Mg%, the Zn content with respect to the Mg content Is excessive, the effect of suppressing activation by Mg oxide is increased, and the pit formation during the electrolytic treatment becomes nonuniform, and the rough surface formation tends to be nonuniform. In the case of Mg> 4 × Zn%, since the Zn amount is too small relative to the Mg amount, the activation suppressing action by the Mg oxide is small, and in this case also, the pit formation during the electrolytic treatment becomes non-uniform. The rough surface formation tends to be uneven.

  Fe produces an Al—Fe intermetallic compound, and coexists with Si to produce an Al—Fe—Si intermetallic compound, and the recrystallization structure is refined by the dispersion of these compounds. Becomes the starting point of pit generation and distributes the formation of pits during electrolytic treatment uniformly and finely. The preferable content of Fe is in the range of 0.2 to 0.6%, and if it is less than 0.2%, the distribution of the compound becomes nonuniform, and the formation of pits during the electrolytic treatment becomes nonuniform. If it exceeds 0.6%, a coarse compound is produced, and the uniformity of the roughened structure is lowered.

  Si coexists with Fe to produce an Al—Fe—Si intermetallic compound, and the dispersion of the compound refines the recrystallized structure, and these compounds serve as starting points for pit generation during the electrolytic treatment. The pit formation is uniformly and finely distributed. The preferable content of Si is in the range of 0.03 to 0.15%, and if it is less than 0.03%, the distribution of the compound becomes nonuniform, and the formation of pits during the electrolytic treatment becomes nonuniform. If it exceeds 0.15%, a coarse compound is formed, and precipitation of simple substance Si is likely to occur, and the uniformity of the roughened structure is lowered.

  Cu easily dissolves in aluminum and has the effect of refining pits within a range of 0.03% or less (excluding 0%), but if it exceeds 0.03%, the pits during electrolytic treatment are coarse. And it becomes easy to make it non-uniform. In addition, in this invention, the amount of Cu mixed from the metal | base metal employ | adopted in order to obtain content of the said Fe and Si is about 5-100 ppm (0.0005-0.01%).

  Ti refines the ingot structure and refines the crystal grains. As a result, the pit formation during the electrolytic treatment is made uniform, and streaks are prevented from occurring when processing as a printing plate is performed. The preferable content range of Ti is 0.003 to 0.05%. If the content is less than 0.003%, the effect is small. If the content exceeds 0.05%, a coarse Al-Ti compound is formed. The roughened structure tends to be uneven. In addition, when adding B with Ti for refinement | miniaturization of an ingot structure | tissue, it is preferable to contain Ti in 0.01% or less of range.

  The aluminum alloy plate of the present invention contains Pb: 100 ppm or less, Cr: 100 ppm or less, In: 50 ppm or less, Sn: 50 ppm or less, Ni: 50 ppm or less, Ga: 300 ppm or less, V: 200 ppm or less. However, the effect of the present invention is not impaired.

  The production of an aluminum alloy plate for a lithographic printing plate support according to the present invention is carried out by subjecting the aluminum alloy ingot according to any one of claims 1 to 3 to hot rolling and cold rolling after homogenization treatment. Is called. Intermediate annealing may be performed during the cold rolling. For example, homogenization treatment is performed at a temperature of 400 to 600 ° C., hot rolling is started at a temperature of 350 to 600 ° C., and hot rolling is followed by a rolling work degree in a range of 50 to 98%. Perform cold rolling. In the case of performing the intermediate annealing, after performing the intermediate annealing in the continuous annealing furnace at a temperature of 350 to 550 ° C. for 0 to 30 seconds following the hot rolling, the rolling workability is in the range of 50 to 98%. And cold rolling. Alternatively, cold rolling is performed subsequent to hot rolling, and after the intermediate annealing is performed in the middle of cold rolling, finish cold rolling is performed.

  Examples of the present invention will be described below in comparison with comparative examples, and the effects will be demonstrated based on the examples. These examples are for explaining a preferred embodiment of the present invention, and the present invention is not limited thereby.

Example 1
The aluminum alloy having the composition shown in Table 1 is melted and cast, and both sides of the resulting ingot are chamfered to form a thickness of 500 mm, a width of 1000 mm, and a length of 3500 mm, and homogenized at a temperature of 450 ° C. After the application, heating was started at a temperature of 400 ° C. to start hot rolling, followed by cold rolling after hot rolling, and then finish cold rolling to obtain a plate material having a thickness of 0.30 mm.

  The obtained aluminum alloy plate was subjected to a tensile test at room temperature to measure the tensile strength, and after heating for 8 minutes with a burning processor maintained at a temperature of 280 ° C. as an index of heat and softening resistance, A 0.2% proof stress was measured by performing a test, and the strength as a support and the burning resistance were evaluated. In addition, the proof stress was measured in a direction parallel to the rolling direction of the aluminum alloy plate (L direction), and the tensile strength at room temperature was 160 MPa or more as pass (◯) and less than 160 MPa as disqualification (x). . The 0.2% proof stress after heating at 280 ° C. for 8 minutes (hereinafter, after heating) was 90 MPa or more as pass (◯) and less than 90 MPa as failure (x).

  In addition, the obtained aluminum alloy plate was degreased and neutralized and washed under the treatment conditions shown in Table 2, and then subjected to AC electrolytic surface roughening treatment, and further to remove oxides formed by electrolysis, desmut After the treatment, anodization treatment was performed, washed with water, dried, cut into a certain size, and used as a test material.

For each test material, the surface was observed at a magnification of 500 times using a scanning electron microscope (SEM), and photographs were taken so that the area of the visual field was 0.04 mm ^2. Was evaluated. The evaluation results are shown in Table 3.

  Occurrence of unetched portion: An unetched portion exceeding 20% is evaluated as bad (x), 15 to 20% is good (◯), and less than 15% is evaluated as excellent (◎).

  Uniformity of etch pits: Large pits with an equivalent circle diameter exceeding 10 μm are defective (×) when the area ratio exceeds 20% of all pits, and those with 10 to 20% are good (◯), less than 10% Are rated as good (◎).

As seen in Table 3, the test materials 1, 2, and 10 according to the present invention are all excellent in support strength (tensile strength at room temperature) and burning resistance (0.2% proof stress after heating). And showed good roughening properties. Test materials 3 to 9 are shown for reference.

Comparative Example 1
An aluminum alloy having the composition shown in Table 4 was melted and cast to obtain a plate material having a thickness of 0.30 mm according to the same process as in Example 1. The 2% yield strength and the 0.2% yield strength after heating to a temperature of 280 ° C. for 8 minutes were measured. Further, after degreasing and neutralization washing treatment under the treatment conditions shown in Table 2, AC electrolytic surface roughening treatment is performed, and further, desmut treatment is performed to remove oxides formed by electrolysis, and then anodization is performed. The sample was processed, washed with water, dried, cut into a certain size, and used as a test material. In Table 4, those outside the conditions of the present invention are underlined.

For each test material, the surface was observed at a magnification of 500 times using a scanning electron microscope (SEM), and photographs were taken so that the area of the visual field was 0.04 mm ^2. The same method as 1 was used to evaluate the occurrence of unetched parts and the uniformity of etch pits. The results are shown in Table 5.

  As shown in Table 5, the test material No. No. 11 had a low tensile strength at room temperature and a 0.2% proof stress after heating due to a small amount of Mg, and there were many unetched parts and non-uniform pits. Test material No. Since No. 12 had a large amount of Mg, the pit size varied. Test material No. No. 13 has a small amount of Zn, so the pit size is non-uniform. Since No. 14 had a large amount of Zn, coarse pits were generated and unetched portions increased. Test material No. Since No. 15 had a large amount of Mn, coarse pits were generated and the pit sizes were non-uniform.

  Test material No. No. 16 has a small amount of Fe, so the formation of pits becomes non-uniform. Since No. 17 had a large amount of Fe, coarse pits were formed and unetched portions were generated. Test material No. No. 18 has a small amount of Si, so the pit size is uniform in the form, and the test material No. Since No. 19 had a large amount of Si, coarse pits were generated and the pit sizes were not uniform. Test material No. Since 20 had a large amount of Cu, the number of unetched portions increased.

Test material No. No. 21 has a large amount of Ti, so coarse pits are formed. Since No. 22 had a small amount of Mg, Zn and Mn, the tensile strength at room temperature and the 0.2% yield strength after heating were low.

Claims (2)

Mg: 0.1-0.3% (mass%, the same applies hereinafter), Zn: more than 0.05% and 0.5% or less, Fe: 0.2-0.6%, Si: 0.03-0 A lithographic printing plate comprising 15%, Cu: 0.02% or less (excluding 0%, the same shall apply hereinafter), Ti: 0.003 to 0.05%, and the balance being Al and impurities Aluminum alloy plate for use. 2. The aluminum alloy plate for a lithographic printing plate according to claim 1, wherein the Mg content and the Zn content satisfy a relationship of 0.4 × Zn% ≦ Mg% ≦ 4 × Zn%.