JP2002331767A - Manufacturing method of substrate for lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate recycling of a lithographic printing plate after being used by a user by a method wherein a very inexpensive material is employed and a cost for recovery is contrived so as not to be increased. SOLUTION: A used aluminum can C is not used in the recycling route R as the material of a high purity aluminum alloy having an aluminum content of 99.5 wt.% or more but is used as a low purity material having the aluminum content of 95-99.4 wt.%. The lithographic printing plate A2, manufactured by the low purity aluminum, is not required to be manufactured by aluminum, whose composition is controlled strictly, whereby the cost of the material can be reduced remarkably by utilizing the used aluminum can C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a lithographic printing plate support.

[0002]

2. Description of the Related Art Conventionally, a lithographic printing plate support is manufactured by subjecting one or both surfaces of an aluminum alloy plate to a surface roughening treatment and then performing an anodizing treatment to improve abrasion resistance. You. A lithographic printing plate precursor is produced by providing a photosensitive layer on this lithographic printing plate support. Further, in order to shorten the vacuum adhesion time during plate making, fine irregularities called mat layers may be provided on the surface of the photosensitive layer.

The lithographic printing plate precursor manufactured as described above is subjected to plate making processes such as image exposure, development, washing with water, etc., to obtain a lithographic printing plate. The method of image exposure is such that a lithographic film on which an image has been printed is brought into close contact with it and exposed to light to make a difference between the image area and the non-image area, using a laser, or directly projecting an image. A method of writing a difference between an image portion and a non-image portion by writing the image portion or the non-image portion, or the like is used.

In the developing process after image exposure, the undissolved photosensitive layer forms an image area as an ink receptor, and the portion where the photosensitive layer has been dissolved and removed is exposed to the underlying aluminum alloy or anodized film. Then, a non-image portion is formed as a water receptor. After the development, if necessary, a hydrophilization treatment, gumming, burning treatment and the like may be performed.

[0005] The lithographic printing plate is mounted on a cylindrical plate cylinder of a printing press and supplies ink and dampening solution to the plate cylinder. Water adheres to the non-image part of the nature. After transferring the ink in the image area to the blanket cylinder, an image is printed on the paper from the blanket cylinder. Here, if the adhesion between the image area and the photosensitive layer is insufficient, there is a problem that printing is completed with a small number of sheets. As a method for improving the adhesion between the image and the photosensitive layer, a method of providing an intermediate layer between the aluminum alloy plate and the photosensitive layer, a method of uniformly roughening the aluminum alloy plate, and the like are known. .

As the intermediate layer, JP-A-60-14949
No. 1 and amino acids and salts thereof (N
alkali metal salts such as a salt and K salt; ammonium salt; hydrochloride; oxalate; acetate; phosphate;
Amines having a hydroxyl group and salts thereof (hydrochloride; oxalate; phosphate; etc.) disclosed in JP-A-232998, amino group and phosphonic acid disclosed in JP-A-63-165183 A compound having a group or a salt thereof can be used as an intermediate layer for undercoating. Further, a compound having a phosphonic acid group disclosed in JP-A-4-282637 can be used as the intermediate layer. Further, after the alkali metal silicate treatment, a method disclosed in Japanese Patent Application No. 9-264309 (Japanese Patent Application Laid-Open No.
It is known to use a polymer compound containing an acid group and an onium group described in US Pat. However, the method of providing the intermediate layer for adhesion between the rough surface and the photosensitive layer naturally has a problem that the production cost for providing the intermediate layer increases.

On the other hand, in order to perform the surface roughening treatment uniformly,
There is known a method of limiting an alloy component contained in an aluminum alloy and having a large effect on surface roughening.

[0008] Many proposals have been disclosed as methods for limiting alloy components. For example, regarding the JIS1050 material, the inventors of the present invention disclosed in JP-A-59-153861.
JP-A-61-51395, JP-A-62-19595
146694, JP-A-60-215725, JP-A-60-215726, and JP-A-60-2
No. 15727, Japanese Unexamined Patent Publication No. Sho 60-215728,
JP-A-61-272357, JP-A-58-117
No. 59, JP-A-58-42493, JP-A-5-42493
JP-A-8-222254, JP-A-62-148295, JP-A-4-254545, JP-A-4-16
The technology is disclosed in Japanese Patent Publication No. 5041, Japanese Patent Publication No. 3-68939, Japanese Patent Laid-Open Publication No. 3-234594, Japanese Patent Publication No. 1-47545, and Japanese Patent Laid-Open Publication No. 62-140894. Japanese Patent Publication No. 1-35910, Japanese Patent Publication No. Sho 5
No. 5-28874 is also known. JIS107
The No. 0 material was disclosed by the present inventors in JP-A-7-81.
264, JP-A-7-305133, JP-A-8-49034, JP-A-8-73974,
JP-A-8-108559 and JP-A-8-92
No. 679 discloses a technique.

Regarding Al-Mg based alloys, the present inventors have disclosed Japanese Patent Publication No. 62-5080 and Japanese Patent Publication No.
No. 60823, JP-B-3-61753, JP-A-60-203496, JP-A-60-20349
7, JP-B-3-11635, JP-A-61-1
No. 274993, JP-A-62-23794,
JP-A-63-47347, JP-A-63-4734
No. 8, JP-A-63-47349, JP-A-64
-61293, JP-A-63-135294, JP-A-63-87288, and JP-B-4-733.
No. 92, Japanese Patent Publication No. 7-100844, Japanese Unexamined Patent Publication No.
JP-A-2-149856, JP-B-4-73394, JP-A-62-181191, JP-B5-76
No. 530, JP-A-63-30294 and JP-B-6-37116 disclose the technology. Also,
JP-A-2-215599, JP-A-61-2017
No. 47 is also known.

Regarding Al-Mn alloys, the present inventors disclosed in Japanese Patent Application Laid-Open Nos. 60-230951 and
The technology is disclosed in JP-A-306288 and JP-A-2-293189. In addition, Japanese Patent Publication No. 54-4228
No. 4, Japanese Patent Publication No. 4-19290, Japanese Patent Publication No. 4-1
No. 9291, Japanese Patent Publication No. 4-19292, Japanese Patent Application Laid-Open No. 61-35995, Japanese Patent Application Laid-Open No. 64-51992, US5009722, US5028276, and Japanese Utility Model Application Laid-Open No. 4-226394 are also known.

Regarding the Al-Mn-Mg alloy, the present inventors have disclosed the technology in Japanese Patent Application Laid-Open Nos. 62-86143 and 3-222796. Also, Japanese Patent Publication No. Sho 63-60824 and Japanese Patent Application Laid-open No. Sho 60-63
346, JP-A-60-63347, EP2
23737, JP-A-1-283350, U.S. Pat.
S4818300 and BR1222777 are also known.

Regarding Al-Zr-based alloys, the present inventors have disclosed Japanese Patent Publication No. 63-15978 and Japanese Patent Laid-Open Publication
The technology is disclosed in JP-A-51395. Also, JP-A-63-143234 and JP-A-63-14323.
No. 5 is also known. Regarding Al-Mg-Si alloys, BR14221710 and the like are also known.

[0013] However, each of these methods imposes restrictions on the aluminum material, and has a disadvantage in that the degree of freedom in material selection is reduced and expensive new ingots and expensive predetermined alloying elements are required.

For these various alloys, usually, a raw material mainly composed of aluminum is melted, a predetermined metal is added thereto to form a molten aluminum alloy of a predetermined alloy component, and the molten aluminum alloy is subsequently subjected to a cleaning treatment. It is manufactured by casting. In the cleaning treatment, a flux treatment for removing unnecessary gas such as hydrogen in the molten metal; a degassing treatment using Ar gas, Cl gas, etc .; a so-called rigid media filter such as a ceramic tube filter and a ceramic foam filter. And filtering using a filter using alumina flakes, alumina balls, or the like as a filter material, a glass cloth filter, or the like; a process combining degassing and filtering; and the like. These cleaning treatments are desirably performed in order to prevent defects due to foreign substances such as nonmetallic inclusions and oxides in the molten metal and defects due to gas dissolved in the molten metal.

As described above, casting is performed using the molten metal subjected to the cleaning treatment. Regarding the casting method, DC
There are a method using a fixed mold represented by a casting method and a method using a driving mold represented by a continuous casting method.

In the case of the DC casting method, the cooling rate is 1 to
It is set in the range of 300 ° C./sec. In this process, some of the alloying elements described above are dissolved in aluminum, but components that cannot be completely dissolved in aluminum form various intermetallic compounds and remain in the ingot. In the DC casting method, an ingot having a thickness of 300 to 800 mm can be manufactured, and the ingot is subjected to face milling according to a conventional method, and is cut from the surface layer by 1 to 30 mm, preferably 1 to 10 mm. Thereafter, a soaking process is performed as necessary. By performing the soaking process,
Among the intermetallic compounds, unstable ones change to more stable compounds, and some dissolve in aluminum. The remaining intermetallic compound is then hot-rolled,
In the process of performing cold rolling, the diameter is reduced or dispersed, but the type hardly changes. That is, it remains on the aluminum alloy plate which is the support for the lithographic printing plate.

A heat treatment called annealing may be performed before, during, or during the cold rolling. In this case, depending on the annealing heat treatment temperature, some of the elements dissolved in aluminum may precipitate as intermetallic compounds or as a single element. In this case also, the deposits remain on the aluminum alloy plate.

A predetermined thickness (0.1 to 0.1) is obtained by cold rolling.
The flatness of the aluminum alloy plate finished to 0.5 mm) may be improved by a straightening device such as a roller leveler or a tension leveler in order to improve the flatness.

As a casting method, a continuous casting method can be used. In this method, a twin-roll continuous casting method typified by a belt caster such as the Hazley method or a block caster such as the Al-Swiss method can be used. For example, when a twin roll is used, the cooling rate is 100 to 1000 ° C. /
Set to the range of seconds. On the other hand, when a twin belt is used,
The cooling rate is set in the range of 10 to 500C / sec.
In any of the methods, after casting, a predetermined thickness (0.1 to 0.5 mm) is obtained by cold rolling or a rolling process including a combination of hot rolling and cold rolling. At this time, heat treatment can be appropriately performed. The flatness of the aluminum alloy sheet finished to a predetermined thickness by cold rolling may be improved by a straightening device such as a roller leveler or a tension leveler in order to improve the flatness. These features of the continuous casting method have an advantage that the running cost is lower than that of the DC casting method because a facing step required in the DC casting method can be omitted.

Here, in order to make aluminum as a raw material into a predetermined alloy component, an aluminum lump having a purity of 99.7% or more, which is usually referred to as new metal, is used. Aluminum scrap is used. If necessary, an aluminum alloy called a master alloy containing a predetermined element is added, or a metal lump made of a predetermined metal element is added to produce an aluminum alloy material having a desired alloy component.

However, a new metal or an aluminum alloy material containing a predetermined additive element component has a disadvantage that its own cost is high. In addition, when using aluminum scrap whose alloy component is known in an aluminum manufacturing plant, there is a merit in improving the yield of raw materials, but it is not at a low cost.

In response to such a problem that the raw material cost is high, the present inventors disclosed in Japanese Patent Application Laid-Open No. 7-81260, using only an aluminum lump having a purity of 99.7% or more and containing a predetermined element. A method was proposed in which the addition of a mother alloy or metal lump was unnecessary. The present inventors have also disclosed in Japanese Patent Application Laid-Open
Japanese Patent Publication No. 05534 proposes a method of reusing a used lithographic printing plate or a lithographic printing plate that has become defective during production as an aluminum raw material.

However, even if these methods are used, an aluminum lump having an aluminum purity of 99.7% or more is not so inexpensive, and it is difficult to secure a used lithographic printing plate as a stable raw material. No practically significant effect was obtained.

In view of the above problems, the present inventors have found that an aluminum alloy plate having an aluminum content of 95 to 99.4 wt% and containing predetermined impurities has at least:
It has been proposed that a lithographic printing plate support having excellent adhesion to the photosensitive layer and excellent printing durability can be manufactured at low cost by performing surface roughening treatment and anodizing treatment.

This is because the aluminum content is 95-9.
This is a lithographic printing plate support obtained by subjecting at least a 9.4 wt% aluminum alloy plate to a surface roughening treatment and an anodic oxidation treatment.

In particular, at least with regard to the composition,
An aluminum alloy plate containing at least three types of impurity metals among Fe, Si, Cu, Mg, Mn, Zn, Cr, and Ti in the ranges shown below, and having an aluminum content of 95 to 99.4 wt%, At least a lithographic printing plate support that has been subjected to a roughening treatment and an anodizing treatment.

Fe: 0.3 to 1.0 wt% Si: 0.15 to 1.0 wt% Cu: 0.1 to 1.0 wt% Mg: 0.1 to 1.5 wt% Mn: 0.1 to 1 0.5 wt% Zn: 0.1 to 0.5 wt% Cr: 0.01 to 0.1 wt% Ti: 0.03 to 0.5 wt% However, lithographic printing plates made from the above aluminum alloy plates are widely used. To do so, it must be compatible with existing aluminum lithographic printing plate recovery systems.

Here, the existing recovery system is composed of a large number of lithographic printing plates made from aluminum of the class of JIS1050 material having an aluminum content of 99.5 wt% or more, and a part of which has an aluminum content of 97 wt%.
Lithographic printing plates made of aluminum whose composition is strictly controlled, such as 3005 material and 3104 material, are collected as aluminum raw materials and recycled.

Therefore, the aluminum content is 95-9.
When a lithographic printing plate made from an aluminum alloy plate whose composition is not strictly controlled at 9.4 wt% is brought into the above-mentioned collection system, it is necessary to sort and collect the lithographic printing plate according to the purity of the aluminum, and to recycle it. The cost for this increases, which is not preferable.

[0030]

SUMMARY OF THE INVENTION In view of the above facts, the present invention facilitates recycling of a lithographic printing plate after use by a user without using extremely inexpensive raw materials and without increasing collection costs. That is the task.

[0031]

In view of the above-mentioned problems, the present inventors have used an extremely inexpensive used aluminum container as a raw material, and have collected a used aluminum lithographic printing plate generated by a user. We came up with a method that can be recycled without incurring large costs.

That is, according to the first aspect of the present invention, a used aluminum container and a used aluminum lithographic printing plate are used as raw materials and have an aluminum content of 95%.
It is characterized in that a low-purity aluminum alloy of up to 99.4 wt% is cast, heat-treated, and rolled to obtain a rolled plate, and then subjected to a surface roughening treatment and an anodizing treatment.

In the above configuration, the used aluminum container is not used as a raw material of a high-purity aluminum alloy having an aluminum content of 99.5 W% or more, but a low aluminum content of 95 to 99.4 wt%. Used as a raw material for purity.

That is, a lithographic printing plate support made of low-purity aluminum does not need to be manufactured from aluminum whose composition is strictly controlled, unlike a lithographic printing plate support made of high-purity aluminum. By using a used aluminum container,
Raw material costs can be significantly reduced.

According to a second aspect of the present invention, the used aluminum lithographic printing plate has an aluminum content of 9%.
A used lithographic printing plate manufactured from a low-purity aluminum alloy of 5 to 99.4 wt% and a used lithographic printing plate manufactured of a high-purity aluminum alloy having an aluminum content of 99.5 wt% or more. It is characterized by.

In the above configuration, the aluminum content is 95
It is assumed that a low-purity aluminum alloy having a content of 9-9 wt% is cast.
Even if a lithographic printing plate manufactured from a high-purity aluminum alloy of 9.5 wt% or more is mixed, no problem occurs. For this reason, the time and effort for sorting in the recovery step can be greatly reduced.

The invention according to claim 3 is characterized in that the used aluminum container and the used aluminum lithographic printing plate are put into a melting furnace in which aluminum is melted.

In the above configuration, by introducing aluminum as a raw material into the melting furnace, oxidation loss during melting can be suppressed.

The invention according to claim 4 is characterized in that before being put into the melting furnace, an iron member is removed from the used aluminum container and the used aluminum lithographic printing plate. .

In the above configuration, by removing iron members such as an aluminum container and an iron band for bundling an aluminum lithographic printing plate, it is possible to prevent unnecessary impurity metals from being mixed. The invention according to claim 5 is characterized in that moisture is removed from the used aluminum container and the used aluminum lithographic printing plate before being put into the melting furnace.

In the above configuration, by removing water from the aluminum container or the lithographic printing plate made of aluminum, the loss at the time of dissolution can be reduced and the dissolution can be ensured.

The invention according to claim 6 is characterized in that the casting of the low-purity aluminum alloy includes the used aluminum container in an amount of 10% or more by weight.

According to the present invention, there is provided a used lithographic printing plate manufactured from a low-purity aluminum alloy having an aluminum content of 95 to 99.4 wt%, and a high lithographic printing plate having an aluminum content of 99.5 W% or more. A collection center is provided to collect used lithographic printing plates made from high-purity aluminum alloy and used aluminum containers without sorting, and the raw materials required for casting low-purity aluminum alloy are obtained from this collection center. And

In the above configuration, a recovery center is provided for collecting all aluminum raw materials such as used aluminum containers without distinction, and raw materials necessary for casting of a low-purity aluminum alloy are obtained from the recovery center to separate the raw materials. And reduce the cost of recycling.

The invention according to claim 8 is characterized in that a lithographic printing plate support is provided with an identification means for indicating that it is manufactured from a low-purity aluminum alloy having an aluminum content of 95 to 99.4 wt%. I have.

In the above configuration, by providing the identification means on the lithographic printing plate support, the lithographic printing plate support of the present invention is
It is possible to prevent a used lithographic printing plate manufactured from a high-purity aluminum alloy having an aluminum content of 99.5% by weight or more from being mixed into an existing collection route.

[0047]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method for producing a lithographic printing plate support of the present invention will be described below in detail. 1. Manufacturing method of lithographic printing plate support As shown in FIGS. 1 and 2, the lithographic printing plate support 10A
Is manufactured, for example, by subjecting at least an aluminum strip 12 made of an aluminum alloy to a roughening treatment 14 and an anodic oxidation treatment 16. Specifically, the surface roughening process 14 includes (1) a mechanical surface roughening process, and (2)
It is preferable to select from the chemical surface roughening treatment step and (3) the electrolytic surface roughening treatment step alone or in combination. In addition,
If necessary, an acid cleaning treatment step may be performed on the way. After the surface roughening treatment 14, (4) anodizing treatment 1
6 (anodizing treatment step) is performed to finally produce a lithographic printing plate support 10A.

In this embodiment, an aluminum raw material (a used lithographic printing plate A2 manufactured from a low-purity aluminum alloy having an aluminum content of 95 to 99.4 wt%,
Used lithographic printing plate A manufactured from a high-purity aluminum alloy having an aluminum content of 99.5 wt% or more
1, and a used aluminum beverage can C) is cast to produce an aluminum ingot A, and through a rolling step 18 and a heat treatment step 20, an aluminum alloy plate having a thickness of 0.1 to 0.7 mm is produced. The flatness correction is performed according to the above to obtain an aluminum strip 12, which is continuously processed by the above-described processing steps (1) to (4), wound up in a coil shape, and a lithographic printing plate support 10A is manufactured. Is done.

Here, as the aluminum alloy that can be used in the manufacturing method of this embodiment, a purity of 99.
Not only aluminum souls of 7% or more, but also low-purity aluminum ingots such as scrap aluminum materials, secondary ingots, reclaimed ingots, etc., which have been considered difficult to use up to now (including aluminum) 95 to 9
A used lithographic printing plate A2, a used aluminum beverage can C, and a used aluminum box manufactured from a low-purity aluminum alloy of 9.4 wt%). By using a low-purity aluminum soul as a raw material, a lithographic printing plate support can be manufactured at lower cost than conventional methods.

The preferred method for producing the lithographic printing plate support of the present invention is at least Fe, Si, Cu, Mg, M
n, Zn, Cr, Ti, containing five or more impurity metals, and having an aluminum content (purity) of 95 to 99.4 wt.
% Aluminum alloy plate is used. Purity is 99.
When an aluminum alloy plate higher than 4 wt% is used, the cost reduction effect is reduced. If the content is lower than 95 wt%, a large amount of impurities will cause a problem such as cracking during rolling. More preferred aluminum purity is 95-
The content is 99% by weight, more preferably 95 to 97% by weight.

The Fe content is preferably 0.3 to 1.0 wt%. Fe is 0.1-0.
An element contained at about 2 wt%, which has a small amount of solid solution in aluminum and almost remains as an intermetallic compound.
If it is more than 1.0 wt%, cracks are likely to occur during rolling, and if it is less than 0.3 wt%, the cost reduction effect is undesirably reduced. More preferably, the content of Fe is 0.5 to 1.0 wt%.

The content of Si is preferably 0.15 to 1.0 wt%. Si is JIS2000, 4000
It is an element contained in a large amount of scrap of 6000 series materials. In addition, 0.03-0.1wt% for new bullion
It is an element that is contained before and after and exists as a solid solution in aluminum or as an intermetallic compound. When heated during the manufacturing process of the lithographic printing plate support, the solid solution Si
May be precipitated as elemental Si. If the Si content is less than 0.15 wt%, the cost reduction effect will be reduced. A more preferred Si content is 0.3 to 1.0.
wt%.

The content of Cu is preferably 0.1 to 1.0 wt%. Cu is an element contained in a large amount of JIS2000-based and 4000-based scrap. Relatively easy to dissolve in aluminum. Cu content of 0.1
If the amount is less than wt%, the cost reduction effect is reduced. More preferable Cu content is 0.15 to 1.0 wt.
%.

The Mg content is preferably 0.1 to 1.5 wt%. Mg is JIS2000, 3000
-Based, 5000-based, and 7000-based materials. Particularly, since it is contained in a large amount in the can end material, it is one of the main impurity metals contained in the scrap material.
One. Mg is relatively easily dissolved in aluminum and forms an intermetallic compound with Si. If the Mg content is less than 0.1 wt%, the cost reduction effect will be reduced. More preferable Mg content is 0.5 to 1.5 w
t%, more preferably 1.0 to 1.5 wt%.

The Mn content is preferably 0.1 to 1.5 wt%. Mn is an element contained in a large amount of JIS 3000-based material scrap. Especially can body
It is one of the main impurity metals contained in the scrap material because it is contained in a large amount in the material. Mn is also relatively easily dissolved in aluminum and forms an intermetallic compound with AlFeSi. If the Mn content is less than 0.1 wt%, the cost reduction effect will be reduced. A more preferred Mn content is 0.5 to 1.5 wt%, and still more preferably 1.0 to 1.
5 wt%.

The Zn content is preferably 0.1 to 0.5 wt%. Zn is an element particularly contained in JIS 7000 series scrap. Relatively easy to form a solid solution in aluminum. If the Zn content is less than 0.1 wt%, the cost reduction effect will be reduced. A more preferred Zn content is 0.15 to 0.5 wt%.

The Cr content is preferably 0.01 to 0.1 wt%. Cr is JIS 5000 series, 6000
Metal is an impurity metal contained in a small amount in scraps of 7000 series and 7000 series. If the Cr content is less than 0.01 wt%,
The cost reduction effect is reduced. A more preferable Cr content is 0.03 to 0.1 wt%.

The content of Ti is preferably 0.03 to 0.5 wt%. Ti is usually used as a crystal refining material.
It is an element added in an amount of 01 to 0.04 wt%. JIS5
000 series, 6000 series, and 7000 series scraps are relatively large as impurity metals. If the content of Ti is less than 0.03 wt%, the cost reduction effect is reduced. A more preferred content of Ti is 0.05 to 0.1.
3 wt%.

Next, the flow of used lithographic printing plates and the flow of raw materials will be described.

The used lithographic printing plate A2 manufactured by the user and made of a low-purity aluminum alloy having an aluminum content of 95 to 99.4 wt% is collected at the collection center 22 by a collection company. Here, it is put into one input box 24 without separation, and the conventional 10
A used lithographic printing plate A1 manufactured from a high-purity aluminum alloy having an aluminum content of 99.5 W% or more such as 50 materials, 3005 materials, and 3104 materials may be mixed. The used aluminum beverage cans C are also collected at the collection center and put into the input box 24. Although FIG. 3 shows the shape of the aluminum beverage can C, it is preferable that the aluminum beverage can C be cut into aluminum pieces and then carried in order to reliably remove moisture from the inside of the can.

These aluminum raw materials are sent to the iron removing step 29 by the conveyor 26 to remove the iron members 30 such as the iron bands that bundled the lithographic printing plates. Here, a method utilizing magnetic force or the like is employed.

Subsequently, water is removed in a water removing step 33. This is to reduce loss at the time of dissolution and to ensure dissolution.

Then, these are fed into an aluminum melting furnace 34 by an elevator 36 as aluminum raw materials. In order to suppress the oxidation loss at the time of melting, it is desirable to put it into the molten metal that has been melted in advance. Then, after performing a molten metal process, it is made into the aluminum ingot A in the casting step 40. In the casting step, a DC casting method or a continuous casting method is used.

In the above example, the lithographic printing plates A1, A
In the above, an example has been described in which the container 2 and the beverage can C are collected in the same collection center 22, but it goes without saying that the optimum location is selected depending on the geographical relationship between the collection area and the location where the aluminum raw material is melted.

For example, if a point suitable for collecting lithographic printing plates and a point suitable for collecting beverage cans are far from each other, a primary collection place is provided, and a final collection place is provided in a place adjacent to the melting place of the aluminum raw material. A center can be provided. It is desirable that the removal of the iron members and the removal of the water be performed collectively at the collection center 22, but it may be performed at each primary collection place. In particular, the removal of water may be performed immediately before dissolution of aluminum in order to eliminate the possibility of adhesion of water during transfer.

Hereinafter, each processing step in the method for producing a lithographic printing plate support of the present invention will be described step by step. However, the following processing steps are exemplifications, and the present invention is not limited to the contents of the following steps. <1. Mechanical surface roughening step and alkali etching step> First, the aluminum band is mechanically roughened with brush grains using a pamistone suspension (mechanical surface roughening step). Thereafter, the aluminum strip is subjected to an alkali etching treatment with an aqueous solution of an alkali agent in order to smooth the unevenness of the surface and remove abrasive particles remaining on the surface (alkali etching treatment step). As the alkali agent used for the alkali etching treatment, caustic soda, caustic potash, sodium metasilicate, sodium carbonate, sodium aluminate, sodium gluconate and the like are preferable. The concentration of the alkaline agent in the aqueous solution is preferably from 0.01 to 30 wt%, and the treatment temperature is preferably from 60 to 80 ° C in order to increase the productivity. As the etching amount of the aluminum strip,
It is preferably 0.1 to 15 g / m ² . The processing time is preferably in the range of 2 seconds to 5 minutes in accordance with the amount of etching, and more preferably 2 to 10 seconds in order to improve productivity.

The step of the mechanical surface roughening treatment is an optional step. After the alkali etching treatment without performing such treatment, the aluminum band is directly subjected to electrolytic surface roughening treatment, and the subsequent treatment is performed. May be performed. Further, in order to remove the smut formed on the surface of the aluminum strip after the alkali etching treatment, a desmut treatment with nitric acid (nitric acid treatment) may be performed. <2. Electrolytic surface-roughening process> In recent years, in the manufacturing process for manufacturing a lithographic printing plate support from an aluminum strip, the adhesion between the photosensitive layer in the image area formed on the lithographic printing plate and the surface of the aluminum strip has been improved. In order to improve the water retention in the non-image area or to improve the water retention in the non-image area, an electrolytic surface roughening treatment is often performed on the aluminum strip using an electrolytic solution mainly containing hydrochloric acid or nitric acid. This electrolytic surface roughening treatment may be performed by superimposing on the surface of the aluminum band obtained by the above-mentioned mechanical graining treatment such as brush grain, or the surface of the aluminum band may be subjected to a pretreatment such as alkali cleaning. It can also be performed directly after performing.

Here, in the present specification, “mainly” means that in a solution of an acid or an alkali, an acid or an alkali as a main component is not less than 30% by weight, preferably 50% by weight, based on the entire acidic or alkaline component. % By weight.

The electrolytic surface roughening treatment on the aluminum strip is performed by etching in an electrolytic solution mainly composed of hydrochloric acid or nitric acid using an alternating current as an electrolytic current. The frequency range of the AC electrolysis current is 0.1 to 1
The frequency is preferably set to 00 Hz, and more preferably to 10 to 60 Hz. Regardless of whether the electrolyte is mainly composed of hydrochloric acid or nitric acid, the concentration of the solution is preferably 3 to 150 g / l, more preferably 5 to 50 g / l.

The amount of aluminum dissolved in the electrolytic cell is preferably 50 g / liter or less,
g / liter is more preferable. If necessary, various additives may be added to the electrolyte. However, when such an additive is mass-produced, it is difficult to control the concentration of the electrolyte in the aluminum strip. There is a need.

[0071] The current density is preferably a 5~100A / dm ^2, and more preferably, 10~80A / dm ^2. Further, the waveform of the electrolytic current is appropriately selected depending on the required quality, the components of the aluminum strip used, and the like, and is disclosed in JP-B-56-19280 and JP-B-55-19191. It is preferable to use a special AC waveform. The waveform of the electrolytic current and the conditions of the electrolytic solution are appropriately selected according to the required quality, the components of the aluminum strip used, and the like, together with the amount of electricity supplied per unit area of the aluminum strip. <3. Acid cleaning step> Smut and intermetallic compounds are present on the surface of the aluminum strip which has been electrolytically roughened as described above. For example, when only the smut is efficiently removed, at least an alkali treatment using an alkali solution (alkali treatment step) is performed, and then a cleaning treatment is performed with a low-temperature acidic solution.

First, as an alkali treatment, the aluminum strip is treated with an alkaline solution to dissolve the smut. As the alkaline solution, there are various ones such as caustic soda, and it is preferable to treat the aluminum strip with an alkaline solution having a pH of 10 or more and a liquid temperature of 25 to 80 ° C. The liquid temperature at this time can be 30 to 80 ° C., but from the viewpoint of improving productivity, the liquid temperature of the alkaline solution is set at 60 to 80 ° C.
It is more preferable that the temperature be set to 80 ° C. Liquid temperature 60 ~ 80 ℃
Thus, the alkali treatment of the aluminum strip can be completed in a very short time of 1 to 10 seconds. As the alkali treatment with the alkali solution, a dipping method, a shower method, a method of applying an alkali solution to an aluminum strip, or the like can be employed.

Next, the aluminum strip is subjected to an acid cleaning treatment with an acidic solution (acid cleaning treatment step). As the acidic solution, a solution mainly containing sulfuric acid is preferable. As the processing equipment, it is preferable to use the equipment described in Japanese Patent Application No. 2000-123805. The liquid concentration (acid concentration) is 1
It is preferably from 100 to 200 g / liter. When the acid concentration is less than 100 g / liter, the effect of removing the smut is reduced. On the other hand, if it is higher than 200 g / liter, intermetallic compounds other than smut are easily removed.

The temperature of the acidic solution is preferably 20 to 80 ° C. If the temperature is lower than 20 ° C., a cooling device for controlling the temperature is required, which is not preferable in terms of equipment cost. 50 ℃
If it is higher, the removal of intermetallic compounds can be promoted in addition to the removal of smut. The acid cleaning treatment with an acidic solution can be generally performed by a dipping method, a shower method, a method of applying the solution to an aluminum strip, or the like. <4. Anodizing Step> Anodizing is performed on the aluminum strip subjected to desmutting with the alkali solution and the acidic solution as described above (anodizing step). As a result, an anodic oxide film is formed on the surface layer.
The amount of the anodized film formed is preferably from ^{0.1~10g / m 2, 0.3~5g / m} 2 is more preferable. Further, other conditions of the anodizing treatment cannot be unconditionally set because it is necessary to change the setting depending on the electrolytic solution (sulfuric acid, phosphoric acid, oxalic acid, chromic acid, etc.). The liquid concentration (acid concentration) is 1-80 wt%, and the liquid temperature is 5-70.
° C, current density is 0.5-60 A / dm ² , voltage is 1-1.
It is preferable that the electrolysis time is 00 V and the electrolysis time is 1 second to 5 minutes.

The aluminum strip that has undergone each of the above-described processing steps is wound into a coil shape to produce a lithographic printing plate support.

Since the anodic oxide film formed on the aluminum strip is stable and has sufficiently high hydrophilicity, a photosensitive material is immediately applied to the surface of the anodic oxide film to form a photosensitive layer. It can be formed, and can be subjected to a surface treatment as needed. The surface treatment includes, for example, providing a silicate layer of an alkali metal silicate or an undercoat layer of a hydrophilic polymer compound on the surface of the aluminum strip. At this time, the coating amount of the undercoat layer is 1 to 150 m
g / m ² is preferred.

A lithographic printing plate precursor is produced by providing a photosensitive layer on the surface of a lithographic printing plate support provided with an undercoat layer if necessary. Further, the mat layer can be applied after the application and drying of the photosensitive layer.

The lithographic printing plate precursor thus obtained is made into a lithographic printing plate through steps such as image exposure and development.
Set on the printing press.

According to the manufacturing method as described above, it becomes possible to use an extremely inexpensive raw material without strictly controlling the alloy composition and the manufacturing process of the aluminum raw material as the raw material.
In addition, it is possible to provide a circulation type lithographic printing plate manufacturing system that manufactures a lithographic printing plate support from a low-purity aluminum raw material without performing complicated collection and separation of lithographic printing plate waste generated by a user. .

[0080]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

The embodiment will be described with reference to FIGS.

In the recovery center 22, in addition to a lithographic printing plate A2 and a used beverage aluminum can C made of an aluminum alloy plate whose aluminum content is 95 to 99.4 wt% and whose composition is not strictly controlled, an aluminum content is mainly increased. Conventional lithographic printing plates A1 made of aluminum in the class of JIS 1050 material having a rate of 99.5 wt% or more are also collected without distinction.

Thereafter, in an iron removing step 29, an iron beverage can,
The iron member 30 such as an iron band is removed. Iron member 3
For removing 0, a magnet separator 28 was used. Next, in a moisture removing step 33, moisture is removed. This is to prevent the occurrence of loss at the time of dissolving aluminum and to surely dissolve aluminum. Specifically, a method of charging into the heating furnace 32 and evaporating water was used.

Here, it is also possible to burn off non-metallic components such as the paint of the beverage can C and the photosensitive layer of the lithographic printing plates A1 and A2 using a rotary kiln or the like.

The above-mentioned aluminum is used as a raw material and put into a melting furnace filled with about half of the molten metal to be melted.
Next, a dissolution processing step 3 such as stirring, molten metal filtration, degassing, etc.
After performing step 4, an aluminum ingot A is manufactured in a casting step 40.

Next, through a rolling step 18 and a heat treatment step 20, an aluminum alloy plate having a thickness of 0.1 to 0.5 mm is produced, and if necessary, the flatness is corrected to form an aluminum strip 12 to obtain a rough surface. After the photosensitive layer coating 42 is performed through the chemical treatment 14 and the anodic oxidation treatment 16, a drying treatment 44 is performed. Then, the rolled aluminum strip is cut into a predetermined size to complete a planographic printing plate A2 as a product.

The lithographic printing plate A2 is prepared by a user in a plate making step of printing an image with a lithographic film or a laser drawing device,
After the development process, it is mounted on a printing machine and used for printing.

The used lithographic printing plate A2 is removed from the printing press and collected by a collection company. The used lithographic printing plate A2 collected by the collection company is collected at the collection center 22 without being separated from the lithographic printing plate A1 derived from the conventional recycling route R and strictly controlling the composition of the 1050 materials.

As described above, the method of the present invention is a method of manufacturing a lithographic printing plate which can coexist with a conventional lithographic printing plate by using an extremely inexpensive material and constructing a circulation type production system. You can see that.

Further, in the above embodiment, an example in which all the raw materials are collected at the collection center has been described. However, a primary collection center can be provided at an appropriate place according to geographical factors.

Further, in order to prevent the used lithographic printing plate A2 from being mixed into the recycling route R of the used lithographic printing plate A1, a mark M indicating that it was manufactured from a low-purity aluminum alloy by printing or the like on the back surface of the photosensitive layer. (See FIG. 3).

[0092]

Since the present invention has the above-mentioned structure, it is possible to use an extremely inexpensive raw material without strictly controlling the alloy composition and the production process of the aluminum raw material as the raw material.
In addition, a lithographic printing plate support can be manufactured from a low-purity aluminum raw material without having to perform complicated collection and separation on a lithographic printing plate generated by a user.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a method for producing a lithographic printing plate support according to the present embodiment.

FIG. 2 is a block diagram illustrating a method for manufacturing a lithographic printing plate support according to the embodiment.

FIG. 3 is a conceptual diagram showing marks provided on the back surface of a lithographic printing plate.

[Explanation of symbols]

22 Collection center 29 Iron removal step 33 Water removal step 34 Melt treatment step A1 Used lithographic printing plate manufactured from a high-purity aluminum alloy having an aluminum content of 99.5 wt% or more A2 Aluminum content of 95 to 99. Used lithographic printing plate manufactured from low-purity aluminum alloy of 4 wt% C Used aluminum can (used aluminum container) M mark

Claims (8)

[Claims] 1. A rolled plate obtained by casting, heat-treating and rolling a low-purity aluminum alloy having an aluminum content of 95 to 99.4 wt% from a used aluminum container and a used aluminum lithographic printing plate as raw materials. And then subjected to a roughening treatment and an anodizing treatment, the method for producing a lithographic printing plate support. 2. The used lithographic printing plate according to claim 1, wherein the used lithographic printing plate is a used lithographic printing plate manufactured from a low-purity aluminum alloy having an aluminum content of 95 to 99.4 wt%, and an aluminum content of 99.5 wt%. 2. The method for producing a lithographic printing plate support according to claim 1, wherein the lithographic printing plate is a used lithographic printing plate manufactured from a high-purity aluminum alloy having a concentration of not less than 10%. 3. The lithographic printing method according to claim 1, wherein the used aluminum container and the used aluminum lithographic printing plate are put into a melting furnace in which aluminum is melted. A method for producing a plate support. 4. The lithographic printing plate according to claim 3, wherein an iron member is removed from the used aluminum container and the used aluminum lithographic printing plate before being put into the melting furnace. Method for producing a printing plate support 5. The method according to claim 3, wherein water is removed from the used aluminum container and the used aluminum lithographic printing plate before being put into the melting furnace. Method for producing a lithographic printing plate support 6. The lithographic printing plate support according to claim 1, wherein the used aluminum container is included in the casting of the low-purity aluminum alloy by 10% or more by weight. Manufacturing method 7. An aluminum content of 95 to 99.4 w
used lithographic printing plate manufactured from a low-purity aluminum alloy having a t% of%, a used lithographic printing plate manufactured from a high-purity aluminum alloy having an aluminum content of 99.5 W% or more, and a used aluminum container. A lithographic printing plate support according to any one of claims 1 to 6, wherein a collection center for collecting without separating is provided, and raw materials necessary for casting of the low-purity aluminum alloy are obtained from the collection center. Body manufacturing method 8. An aluminum content of 95 to 99.4 w.
The lithographic printing plate support according to any one of claims 1 to 7, wherein an identification means for indicating that the lithographic printing plate is manufactured from a low-purity aluminum alloy of t% is provided on the lithographic printing plate support. Manufacturing method