JPS6274060A - Manufacture of support for lithographic printing plate - Google Patents

Abstract

PURPOSE:To manufacture a support for a lithographic printing plate having a small extent of spring-back and superior burning resistance by heat treating an Al alloy ingot having a specified composition consisting of Mg, Ku and Al under specified conditions and by carrying out proper cold rolling. CONSTITUTION:An Al alloy ingot consisting of 0.5-2.5wt% Mg, 0.05-0.5wt% Cu and the balance Al with impurities is soaked at >=450 deg.C, and after hot rolling or during cold rolling, the ingot is heated to 450-600 deg.C at >=100 deg.C/min heating rate, held at the temp. for <=10min and cooled at once to <=150 deg.C at >=100 deg.C/hr cooling rate. It is then cold rolled at >=30% draft. Thus, a support for a lithographic printing plate having a small extent of spring-back, superior resistance to breaking, burning and bite-cracking and satisfactory etchability is obtd.

Description

Detailed Description of the Invention [Industrial Field of Application 1] The present invention relates to a method for producing a lithographic printing plate support, and more specifically, the present invention relates to a method for producing a lithographic printing plate support, and more specifically, a support that exhibits minimal softening and ease of handling even when subjected to burning treatment to improve printing durability. The present invention relates to a method for producing a lithographic printing plate support which has excellent burning resistance and grip cracking resistance of the printing-like mounting portion.

[Prior Art 1 Conventionally, aluminum plates for planographic printing plates used in mechanical surface roughening methods such as brush polishing are
1050, which corresponds to Al100SA3003, is used, and A1050 is also used as an aluminum plate for lithographic printing plates used in electrolytic surface roughening.

However, in recent years, there has been a strong trend toward thinner planographic printing plates to reduce their weight, but when pure aluminum plates are made thinner, folds and bends occur during handling. , the problem of [plate elongation] occurred during printing.

In addition, in order to improve the printing durability of the printing plate, after the printing plate is developed, it is usually subjected to a burning process at a temperature of 200 to 300°C for 3 to 10 minutes to thermoset the resin in the image area on the aluminum plate. There are cases.

However, in general, photosensitive lithographic printing plates using conventional aluminum plates undergo significant softening due to burning treatment, which may cause problems such as bending of the plate during handling.

A conventional method for improving the aluminum plate for plain printing plates, which has such problems, will be described.

(1) Japanese Patent Application Laid-Open No. 59-06734 aimed at improving the burning and softening resistance while keeping the composition of pure aluminum cum.
There is a method described in Publication No. 9, which has a large effect in terms of reducing yield strength, but since the absolute value of strength is originally low, the improvement in handleability is not significant, and the improvement in grip cracking resistance is The effect is small.

(2) Japanese Patent Laid-Open No. 60-06 discloses that the absolute value of strength can be increased and handleability improved by further containing alloying elements in aluminum or aluminum alloy.
Although it is described in Publication No. 3346, the bqg content is 2
．． When the Mg content is 58 wt% or more, a uniform finely etched surface can be obtained, but when the Mg content is less than 2.5 ht%, the
There is a slight problem with the uniformity of the coating, and if the Mg content exceeds 2.58 wt%, the absolute value of the strength becomes extremely high, making it easy to cause springback problems. According to Japanese Patent No. 59-133355, when the Mg content is 0.76 d% and the Cu content is 0.11...t%, the surface by electrolytic etching is excellent, but there is a problem in grip cracking resistance.

(3) Furthermore, in recent years, there has been a demand for aluminum alloy plates that have a bending durability (repetitive bendability) of a certain level or more, regardless of the rolling direction of the supporting body in relation to the arrangement of printing plates. Ta.

[Problems to be Solved by the Invention] The present invention has been made to solve various problems in conventional aluminum plates for lithographic printing plates as explained above, and the present invention has been developed through intensive research. As a result, there is little strength loss during burning, excellent folding durability regardless of the rolling direction, a small amount of bleedback, no occurrence of "folding" or "beef", and etching resistance. They have developed a method for producing a lithographic printing plate support that has excellent burning resistance and grip cracking resistance.

[Means for Solving the Problems 1] The Vf characteristics of the method for producing a lithographic printing plate support according to the present invention are as follows: Mg 0.5-2.5 wt%, Cu 0.05-0. ht
%, the balance consisting of aluminum and impurities, is soaked at a temperature of 450 ° C. or higher, and after hot rolling or during cold rolling,
100' (: 450-60 at a heating rate of over
Heating to a temperature of 0°C and maintaining heating for less than 10 minutes,
The object is to immediately cool the material to a temperature of 150'C or less at a cooling rate of 100'C/Hr or more, and then cold-roll at a rolling reduction of 30% or more.

The method for producing a lithographic printing plate support according to the present invention will be described in detail below.

First, the components and component ratios of the aluminum alloy used in the method for producing a lithographic printing plate support according to the present invention will be explained.

Mg1. It is necessary to contain Cu in coexistence with tCu.
It is an element that imparts the strength necessary as a lithographic printing plate support by forming a solid solution through solution treatment and then precipitation hardening, and if the content is less than 0.5 wL%, sufficient strength cannot be obtained for burning treatment. Moreover, the bending resistance parallel to the rolling direction cannot be guaranteed against grip cracking, and 2.5L%
If the content exceeds 100%, the strength of the lithographic printing plate support will increase even after burning treatment, and problems of springback and distortion will occur, making it undesirable as a lithographic printing plate support. Therefore, the N18 content is estimated to be 0.5 to 2.5 wt%.

Cu is burnt together with Mg l) AI-M.

- An element that forms fine precipitates of Cu-based compounds to harden and reduce strength loss, with a content of 0.05 w
Such an effect cannot be expected below t%;
Furthermore, if the content exceeds 0.5 wt%, the strength increases and the surface becomes uneven and rough due to spring bank or electrolytic etching. Therefore, the Cu content is set to 05 to 0.5 wt%.

In addition to Mg and Cu, SiO03+u is an impurity.
t% or less, Fe0.7u+t% or less, Mn 0.3uu
t% or less, Cr 0.1u+t% or less, Zn 0.1u
+t% or less and Ti0.05u+t% or less will not impede the properties of the lithographic printing plate support obtained by the method for producing a lithographic printing plate support according to the present invention. If so, it is acceptable.

Next, a heat treatment method in the method for producing a lithographic printing plate support according to the present invention will be explained.

The reason why an aluminum alloy ingot having the above-mentioned components and ratios is subjected to soaking treatment at a temperature of 450°C or higher is because sufficient homogenization cannot be obtained at a temperature lower than 450°C.
This is also because it inhibits hot rolling properties.

Hot rolling after soaking treatment does not require any particular control;
Heat treatment is performed after hot rolling or during cold rolling, and the heating temperature for this treatment is 450 to 600°C, which makes the recrystallized grains fine and uniform. I) It is possible to improve the grip cracking resistance of the lithographic printing plate support, and furthermore, Cu can be used to improve the burning resistance by precipitation hardening of AlMg-Cu based compounds.
At temperatures below 450°C, the effect of solutioning is insufficient, and at temperatures above 600°C, recrystallized grains become coarse. Therefore, the heating temperature is 4
50-600'C.

The heating rate to reach this heating temperature needs to be rapid. In particular, in order to refine the recrystallized grains, such an effect cannot be expected unless the heating rate is set to 100° C./min or more.

In addition, since the holding time at this heating temperature is high temperature heating, it is possible to fully achieve the purpose from the point of view of recrystallized grain refinement, but in the case of a low temperature range, or depending on the contained components and component ratios and the pond manufacturing conditions. It is preferable to hold it for a certain period of time, but since holding it at high temperature for a long time causes coarsening of the recrystallized grains, the holding time should be kept within 10 minutes.

Next, cooling is performed immediately after the above heating, but the cooling rate at this time is important in order to obtain precipitation hardening by burning.
At a slow cooling rate, Al-Mg-
Cuff< Compound precipitates precipitate, and sufficient precipitation hardening cannot be obtained during burning.

Therefore, rapid cooling of 100'C/Hr or more is required.

In addition, unless cooling is performed at the above cooling rate to a temperature of 150°C or less, sufficient precipitation hardening cannot be obtained during burning.
The decrease in strength increases.

Furthermore, the reason why cold rolling is performed at a rolling reduction of 30% or more after cooling is to obtain the necessary strength as a lithographic printing plate support, and it is also related to the contained components and component ratios. However, such an effect cannot be expected if the rolling ratio is less than 30%. Therefore, cold rolling is performed at a rolling reduction of 30% or more.

[Example 1] An example will be described regarding a method for producing a lithographic printing plate support according to the present invention.

Example I Cu 0.1.5u+t% and Mg content 0.1.5u+t%.
3 companies%, 0.5u+t%, 0.8u+t%, 1.5wt
% and 2.5 wt%
@ 7 A l h-h ftr&tJt&+J->
? −? 77- Full Miniram Alloy and Mgo. ht%
- Cu0.05u+t%, 0.11wt%,
0.16wt%, 0.211IIt% and 0.25t
By changing the ut% and content, the aluminum alloy consisting of the balance AI and impurities is melted and cast to form an ff lump of SO+cotton thickness, and g! Set the lump slab thickness to ・45m+m, 590
After soaking at a temperature of 'C for 5 hours, it was hot rolled to a thickness of 40mm+, and then cold rolled to a thickness of 1.3111111mm. The annealed plate was heated to a temperature of 510'C at a heating rate of 510'C, and immediately cooled at a cooling rate of 700°C/Hr to a temperature of 80'C after a holding time of 0 minutes. It was rolled to a thickness of 24 mm.

The thus obtained rolled plate was subjected to a burning treatment for 250'CXS.

Table 1 shows the case where the above-described Cu content is set at 0.15 mt% and the Mg content is changed, and Table 2 shows the case where the above-mentioned Mg content is set at 0.15 mt%. The test results are shown when the Cu content is changed as Su+t%. As a conventional alloy, (A) is A
t~0.6111t%Mg alloy plate, (B) is JIS10
50 alloy plate, each with a thickness of 0.24111 m.

Table 1 shows that when the Mg content is 0°3u+t%, the precipitation of the AIMg-CuJ compound due to the burning process is insufficient, resulting in a significant decrease in yield strength, and the repeated bendability is not much different from that of conventional alloys, but the lithographic plate according to the present invention It can be seen that when the Mg content is 0.5 to 2.5% as in the method for producing a printing plate support, the yield strength decreases little and the repeated bendability is improved.

Table 2 shows that when the Cu content is 0.05wt%, the yield strength after the burning process is greatly reduced, and the number of repeated bendings until fracture is parallel and perpendicular to that of conventional alloys, but especially , the number of parallel bends is lower than the number of right angle bends of conventional alloys, but when the Cu content is 0.11u+t% or more, the number of parallel bends is improved compared to the number of right angle bends of conventional alloys. Although the support was bent and fixed to the printing machine, the support produced by the method for producing a lithographic printing plate support according to the present invention can be fixed in any direction, which means that printing plates can be freely assembled. It can be seen that it is possible to select.

Example 2 M20. Srt%, Cu 0.15u+t%, Si 0
．． An aluminum alloy ingot containing 0.08u+t%, Fe 0.31u+t%, and the balance consisting of impurities of
A plate with a thickness of 1.3IllI+1 was made by soaking, hot rolling, and cold rolling in the same manner as in Example 1, and this plate was
'C/1IIin heating rate (1) 450℃, (2
) 510'C1 (3) 60 (heating temperature of 1°C, holding time 0 minutes, cooling rate of 700'C/i-1r, 8
It was cooled to a temperature of 0°C and cold rolled to a thickness of 0°24+nTII*.

Table 3 shows the test results for different heating temperatures.

When the heating temperature is 450'(:'), the solution ratio of Cu is sufficient and the burning process produces AI';
The precipitation hardening of the system compound is small, the yield strength bottom ratio is large, and the repeat bendability is poor, but at heating temperatures of SOO'C or lower, there is little decrease in proof stress and the repeat bendability is good.

Example 3 An aluminum alloy ingot containing the same component B as in Example 2 was soaked and hot rolled under the same conditions as in Example 1.
Cold rolling was performed to obtain a plate with a thickness of 1.3n+a+, and this plate in the middle of cold-open rolling was heated at a heating rate of 700°C/min to a heating temperature of 510'C, heat treated for a holding time of 0, and immediately cooled. Cooling was performed at a rate of 700°C/Hr to 80°C.
The temperature is ℃. Next, rolling ratio (1) 30%, (2)
Cold rolling was performed at 50%, (3) 60%, and (4) 80%, respectively, to give a plate thickness of 0.24 m.

Table 4 shows changes in strength due to differences in cold opening rolling ratio.

If the cold rolling rate is 30%, work hardening due to rolling is somewhat insufficient and sufficient strength cannot be obtained, so rolling with a cold rolling rate of more than 30%, for example, 50% or more is necessary.

Next, the etching properties of the support obtained by the method for producing a lithographic printing plate support according to the present invention will be explained.

Aluminum alloy ingot (Mg 0.8...t%, Cu
0.15wt%, Si 0.08wt%, Fe 0.
31wt%, the balance A1 and impurities) and conventional alloys (A) and (B) were processed in the same manner as in Example 1 to form a plate with a thickness of 0.2 hm.
And so.

This plate with a thickness of 0.24 mm was subjected to electrolytic surface roughening under the following conditions.

FIG. 2 shows a micrograph showing the metallographic structure of the roughened plate surface. )teeth,
It can be seen from conventional alloys (A) (FIG. 2(b)) and (B) (FIG. 2(a)) that the irregularities are fine and have a double structure.

Electrolytic conditions Pretreatment 3% NaOH 50℃ x 30 seconds 30%HNO325℃X30 seconds Electrolytic bath 1.6% HNO.

Liquid temperature 25℃ Current density 60 A/dm2X 20 seconds post-treatment 3%
NaOH 50°C x 30 seconds ↓ 30% HNO 325°C x 30 seconds [Effect 1 of the invention As explained above, the method for producing a lithographic printing plate support according to the present invention has the above structure. It has a small amount of springback, excellent burning resistance and grip cracking resistance, and further has the effect that a double-structured printing plate surface having fine irregularities can be obtained by electrolytic surface roughening.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of repeated bending and springback.
FIG. 2 is a microscopic photograph of the metal structure resulting from electrolytic surface roughening. ~ Table 1 of -
, L:. 2. Name of the invention Method for manufacturing a lithographic printing plate support 3 Relationship with the case of the person making the amendment Patent applicant address 1-3 Wakihama-cho, Chuo-ku, Kobe City No. 18 Name (1
1,9) Kobe Co., Ltd. ! ! Steelworks representative Fuyuhiko Maki 4, agent address 901 Fujiwa Toyocho Co-op, 2-2-15 Minamisuna, Koto-ku, Tokyo 136 Phone (646) 6194 Name Patent attorney (6937) Ryo Hisashi Maruki i1
';γPa 5, Date of amendment order January 28, 1985 (shipment date) 6, Subject of amendment @2 Figure 7, Contents of amendment as attached.

Claims (1)

[Claims] Mg 0.5-2.5wt%, Cu 0.05-0.5
wt%, with the remainder being aluminum and impurities, is soaked at a temperature of 450°C or higher, and after hot rolling or in the middle of cold rolling, it is heated to 450°C at a heating rate of 100°C/min or higher. ~600
℃, hold the heat for 10 minutes or less, immediately cool to a temperature of 150℃ or less at a cooling rate of 100℃/Hr or higher, and then cold-roll at a rolling reduction of 30% or higher. Characteristic method for producing a lithographic printing plate support.