JP4201469B2 - Method for producing support for lithographic printing plate - Google Patents

Description

【００６３】
【発明の効果】
本発明の平版印刷版は、一方の面に感光層を有し、他方の面に木目状模様またはスジ状模様を有するので、用いられたアルミニウム圧延板の圧延方向の判別が容易であるため製版作業中や印刷機への取付け作業中に縦横の認識を誤ることがなく、取扱い性に優れる。
特に、平版印刷版用支持体に用いるアルミニウム板として、双ロール連続鋳造および冷間圧延により得られるアルミニウム圧延板、または、双ベルト連続鋳造、熱間圧延および冷間圧延により得られるアルミニウム圧延板を用い、アルカリエッチング処理およびデスマット処理により木目状模様またはスジ状模様を設ける場合は、製造工程数を少なくすることができ、極めて有用である。
【図面の簡単な説明】
【図１】 裏面に木目状模様を有する本発明の平版印刷版の裏面の一例を示す図である。
【図２】 裏面にスジ状模様を有する本発明の平版印刷版の裏面の一例を示す図である。
【符号の説明】
１ 裏面に木目状模様を有する本発明の平版印刷版
２ 裏面にスジ状模様を有する本発明の平版印刷版[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a lithographic printing plateMethod for manufacturing supportIn detail, since the rolling direction of the used aluminum rolled sheet can be easily discriminated, the lithographic printing plate having excellent handleabilityFor producing a support for a lithographic printing plate to be used in a processAbout.
[0002]
[Prior art]
Conventionally, as a lithographic printing plate, an aluminum plate having been subjected to a roughening treatment and provided with a photosensitive layer has been used. This lithographic printing plate is used after the plate making operation for providing an image, and both ends are bent and mechanically attached to the plate cylinder of the printing machine. There has been a problem in that it is damaged and causes problems such as printing misalignment, or the bent portion is cut (ie, is cut out) and printing becomes impossible.
On the other hand, it has been proposed to improve fatigue strength by setting the alloy component of the aluminum plate within a specific range (Japanese Patent Publication No. 3-11635).
However, since the strength characteristics of the aluminum plate are different between the rolling direction and the direction perpendicular thereto, normally, even if the above problems do not occur, the lithographic printing plate is reversed in the vertical and horizontal directions by mistake during the plate-making process or installation in a printing machine. Then, it will be bent along the rolling direction which is weak to bending, and will be attached to a printing machine, and a cutting end may arise. Therefore, there is a demand for a lithographic printing plate that does not misrecognize vertical and horizontal directions during plate making operations or attachment to a printing press.
[0003]
On the other hand, many methods for applying numbers, letters, patterns, designs, etc. to the surface of a planographic printing plate that does not have a photosensitive layer have been proposed. For example, in JP-A-7-76800 and JP-A-6-286352, a surface of a support for a lithographic printing plate on which a photosensitive layer is not provided (hereinafter also referred to as “back surface”. The same applies to a lithographic printing plate). Discloses a method for performing an electrochemical surface roughening treatment, and JP-A-7-205563 discloses a method for performing an alkali etching treatment on the back surface of a lithographic printing plate support. JP-A-6-305271 discloses a method of subjecting the back surface of a lithographic printing plate support to a press treatment with a transfer roll.
Japanese Patent Application Laid-Open No. 6-73478 discloses a method for obtaining a discontinuous pattern having a specific color tone on an aluminum alloy plate by anodizing treatment.
However, all of these methods require an electrochemical surface roughening treatment, an alkali etching treatment, a pressing process using a transfer roll, or an anodizing treatment. When a lithographic printing plate is produced by applying a pattern, a design, etc., there is a problem that the number of steps increases.
[0004]
[Problems to be solved by the invention]
  Therefore, the present invention is a lithographic printing plate that is excellent in handleability without erroneous recognition of the vertical and horizontal directions during plate making work or mounting work to a printing press.For producing a support for a lithographic printing plate to be used in a processIn particular, lithographic printing plates that are easy to handle and have few manufacturing processes are not misidentified during plate making or mounting on a printing press.For producing a support for a lithographic printing plate to be used in a processThe purpose is to provide.
[0005]
[Means for Solving the Problems]
  The present invention is a lithographic printing plate support production method for producing a lithographic printing plate support by subjecting an aluminum rolled plate obtained by twin roll continuous casting and cold rolling to surface treatment,
  The lithographic printing plate support is a lithographic printing plate support used for a lithographic printing plate having a photosensitive layer on the surface to be roughened,
  A step of performing at least a roughening treatment on the surface that was on the upper side at the time of casting the aluminum rolled plate;
  A process of providing a wood grain pattern by performing alkali etching treatment and desmut treatment on the lower surface when the aluminum rolled sheet is cast;
A method for producing a support for a lithographic printing plate comprising:
[0006]
  The present invention also provides:The alkali etching treatment uses a caustic soda aqueous solution having a pH of 13 or more, and the aluminum dissolution amount is 0.1 to 5 g / m. ² It is given so that
The desmutting treatment is preferably performed by a method in which an acidic aqueous solution having a nitric acid concentration of 1% by mass or more is applied in a shower form.
[0007]
  The present invention also provides:The roughening treatment is a treatment in which an alkali etching treatment, a desmut treatment, an electrochemical roughening treatment and an anodizing treatment are performed in this order,
It is preferable that the alkali etching treatment and the desmut treatment in the roughening treatment and the alkali etching treatment and the desmut treatment in the step of providing the wood grain pattern are performed simultaneously.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
  The present invention is described in detail below.
  The present inventionApply roughening treatmentProvided is a method for producing a support for a lithographic printing plate for use in a lithographic printing plate having a photosensitive layer on its surface and having a wood grain pattern or streak pattern on the other surface.
  A lithographic printing plate using a lithographic printing plate support obtained by the production method of the present invention (hereinafter referred to as “the lithographic printing plate of the present invention”) has a grain-like pattern on the surface having no photosensitive layer, that is, the back surface. Or it has a stripe pattern. FIG. 1 is a diagram showing an example of a lithographic printing plate 1 of the present invention having a grain pattern on the back surface. Moreover, FIG. 2 is a figure which shows an example of the lithographic printing plate 2 of this invention which has a stripe pattern on the back surface.
  As shown in FIGS. 1 and 2, the planographic printing plate of the present invention has a grain-like pattern or streak-like pattern on the back surface, so the rolling direction of the aluminum rolled sheet used is related to the pattern and the rolling direction. Therefore, it is possible to discriminate very easily, and the vertical and horizontal recognition is not mistaken during the plate making operation or the mounting operation to the printing press. Therefore, it is not bent at the time of attachment to a printing machine along the rolling direction which is weak against bending, and the gripping is not caused. That is, the planographic printing plate of the present invention is excellent in handleability.
[0009]
The following methods (1) and (2) are preferably exemplified as a method of providing a wood grain pattern or stripe pattern on the back surface.
(1) Lithographic printing in which an aluminum rolled sheet having a thickness of 0.1 to 0.6 mm obtained by twin-roll continuous casting and cold rolling is subjected to alkali etching treatment and desmut treatment, and a wood grain pattern is provided on the back surface. A method for producing a lithographic printing plate using a plate support.
(2) A 0.1-0.6 mm thick aluminum rolled plate obtained by twin-belt continuous casting, hot rolling and cold rolling is subjected to alkali etching treatment and desmutting treatment, and a streak pattern is provided on the back surface. A method for producing a lithographic printing plate using a lithographic printing plate support.
[0010]
According to the above method (1) or (2), a grain pattern or stripe pattern derived from the aluminum crystal structure of the aluminum rolled sheet used is obtained.
That is, (1) the lithographic printing plate comprising a photosensitive layer provided on the surface subjected to the roughening treatment of the lithographic printing plate support, wherein the lithographic printing plate support comprises a twin roll continuous casting and At least roughening treatment is performed on one surface of an aluminum rolled sheet having a thickness of 0.1 to 0.6 mm obtained by cold rolling, and a wood pattern is provided on the other surface by alkali etching treatment and desmut treatment. A lithographic printing plate comprising: a lithographic printing plate comprising: a lithographic printing plate comprising a photosensitive layer provided on a surface subjected to a roughening treatment of a lithographic printing plate support; The plate support is subjected to at least roughening treatment on one surface of an aluminum rolled plate having a thickness of 0.1 to 0.6 mm obtained by twin belt continuous casting, hot rolling and cold rolling, and the other surface. Alkaline etching and desma The lithographic printing plate, characterized in that subjected to preparative process comprising providing a streaky pattern is one of each preferred embodiment of the lithographic printing plate of the present invention.
In particular, if the alkali etching treatment and the desmut treatment are simultaneously performed on the surface on which the photosensitive layer is provided and the back surface by the above method (1) or (2), a wood-like pattern on the back surface is not required without requiring a special processing step. Alternatively, since a streak-like pattern is obtained, the lithographic printing plates (1) and (2) thus obtained are particularly suitable.
[0011]
Furthermore, although it demonstrates in detail, giving a specific example, this invention is not limited to these.
The aluminum plate used in the lithographic printing plate according to the present invention is a metal mainly composed of dimensionally stable aluminum, and is made of aluminum or an aluminum alloy. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements can also be used.
[0012]
In the following description, various substrates made of aluminum or an aluminum alloy listed above are collectively used as an aluminum plate. The foreign elements that may be contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium, and the content of the foreign elements in the alloy is 10% by mass or less. It is.
[0013]
In the present invention, it is preferable to use a pure aluminum plate. However, it is difficult to produce completely pure aluminum in terms of refining technology, so it may contain a slightly different foreign element. Thus, the composition of the aluminum plate used in the present invention is not specified, and conventionally known materials such as JIS A1050, JIS A1100, JIS A3005, JIS A3004, internationally registered alloy 3103A, etc. An aluminum alloy plate can be used as appropriate. Moreover, the thickness of the aluminum plate used for this invention is about 0.1-0.6 mm. This thickness can be changed as appropriate according to the size of the printing press, the size of the printing plate, and the desire of the user.
[0014]
In order to obtain said aluminum plate, the following method is employable, for example. First, a cleaning treatment is performed on a molten aluminum prepared as a desired component according to a conventional method. For cleaning treatment, in order to remove unnecessary gas such as hydrogen in the molten metal, flux treatment, degassing treatment using Ar gas, Cl gas, etc., so-called rigid media filters such as ceramic tube filters, ceramic foam filters, etc. In addition, a process using a filter using alumina flakes, alumina balls, or the like, a glass cloth filter, or the like, or a combination of degassing and filtering is performed.
[0015]
Next, the molten aluminum alloy is cast by twin roll continuous casting or twin belt continuous casting to form an aluminum cast plate, and then rolled to obtain an aluminum rolled plate.
[0016]
First, twin roll continuous casting used in the present invention will be described. First, the ingot is melted and held in a melting and holding furnace. The molten aluminum is supplied from the melting and holding furnace to the twin roll type continuous casting machine, and the aluminum cast plate is directly produced by the twin roll type continuous casting machine. The aluminum cast plate may be directly wound on a coiler to form a coil, or may be subsequently wound on a coiler after being processed by a cold rolling mill, a heat treatment device, and a straightening device.
[0017]
Manufacturing conditions will be described. In the melting and holding furnace, it is necessary to maintain the temperature at a temperature equal to or higher than the melting point of aluminum, and the temperature varies depending on the aluminum alloy component, but is generally 800 ° C. or higher. Examples of the casting method of the twin roll continuous casting machine include the Hunter method and the 3C method. In general, the casting temperature is optimally around 700 ° C., although it depends on the cooling conditions of the mold. The thickness of the aluminum cast plate produced by the twin roll continuous casting machine can be set to 1 to 30 mm, for example. The crystal grain size after continuous casting, cooling conditions, casting speed, and plate thickness change during casting are appropriately controlled. The aluminum cast plate thus obtained by twin roll continuous casting is rolled to a desired thickness by a cold rolling mill to obtain an aluminum rolled plate. Thereafter, in order to align the crystal grains to a desired size, the heat treatment apparatus may be used for intermediate annealing or the like, and further, the treatment may be performed by a cold rolling mill. Next, a correction process is performed by the correction device, and desired flatness can be given. You may perform this correction process with the last cold rolling mill. The final thickness of the aluminum rolled sheet is preferably 0.1 to 0.6 mm.
[0018]
Next, the twin belt continuous casting used in the present invention will be described. First, the ingot is melted and held in a melting and holding furnace. Molten aluminum is supplied from the melting and holding furnace to the twin belt type continuous casting machine, and an aluminum cast plate is produced by the twin belt type continuous casting machine. After this aluminum cast plate is reduced in thickness with a hot rolling mill to form an aluminum rolled plate, it may be wound around a coiler to form a coil, and subsequently processed by a cold rolling mill, a heat treatment device, and a straightening device. After that, it may be wound on a coiler. Note that twin belt continuous casting has the advantage that the production capacity is very large compared to the twin roll continuous casting.
[0019]
Manufacturing conditions will be described. As a casting method of the twin belt continuous casting machine, for example, the Hazley method using a metal belt and the Al-Swiss Caster II using a caterpillar block can be cited. The thickness of the aluminum cast plate produced by the twin belt continuous casting machine can be, for example, 10 to 100 mm, and the thickness of the aluminum rolled plate rolled by the hot rolling mill is, for example, 1 to 30 mm. can do. Other casting conditions are the same as in the case of the twin roll continuous casting described above. An aluminum rolled sheet obtained by twin belt continuous casting and hot rolling is rolled to a desired thickness by a cold rolling mill. Subsequent processing is the same as in the case of the twin roll continuous casting described above. The final thickness of the aluminum rolled sheet is preferably 0.1 to 0.6 mm.
[0020]
The aluminum plate thus obtained is then subjected to a surface roughening treatment in order to obtain a lithographic printing plate support. The aluminum plate used in the present invention is preferably subjected to a surface roughening treatment including an electrolytic surface roughening treatment, but may be subjected only to an electrolytic surface roughening treatment, and may be subjected to an electrolytic surface roughening treatment and a mechanical surface treatment. You may perform combining a roughening process or a chemical roughening process. Among these, it is more preferable to combine the electrolytic surface roughening treatment with the mechanical surface roughening treatment, and it is particularly preferable to perform the electrolytic surface roughening treatment after the mechanical surface roughening treatment.
In the lithographic printing plate support used in the lithographic printing plate of the present invention, the surface to be subjected to the following surface treatment is not particularly limited, but as an aluminum plate, an aluminum rolled plate obtained by twin-roll continuous casting and cold rolling Is used, the upper surface during casting is the surface on which the photosensitive layer is provided, and the following surface treatment is performed.The lower surface during casting is the back surface, and alkali etching treatment and desmut treatment are performed. It is preferable because the visibility of the pattern on the back surface is excellent.
[0021]
The mechanical surface roughening treatment is generally performed for the purpose of setting the surface of the aluminum plate to an average surface roughness of 0.35 to 1.0 μm. In the present invention, the conditions for this mechanical surface roughening treatment are not particularly limited, and for example, ball grain, wire grain, brush grain, or liquid honing can be used. It can also be carried out according to the methods described in JP-A-6-135175 and JP-B-50-40047. When the mechanical roughening treatment is performed, the surface roughness of the aluminum plate can usually be set to an average arithmetic roughness (Ra) of 0.35 to 1.0 μm. By performing this mechanical surface roughening treatment, the water retention of the non-image area during printing can be increased. On the other hand, the chemical surface roughening treatment is not particularly limited, and a known method can be followed. For example, a method of immersing an aluminum plate in an alkaline bath, a method of spraying an alkaline solution, and a method of applying an alkaline solution are included.
[0022]
The alkali etching treatment was generated by mechanical roughening treatment for the purpose of removing rolling oil, dirt, and natural oxide film on the surface of the aluminum plate, or when mechanical roughening treatment was performed. It is applied for the purpose of obtaining a surface having a smooth undulation by dissolving the uneven edge portion.
The alkali etching process is a chemical etching process in an alkaline aqueous solution. Examples of the alkali used in the alkaline aqueous solution include sodium hydroxide and potassium hydroxide, sodium triphosphate, sodium aluminate, sodium carbonate and the like as described in JP-A-57-16918, These can be used alone or in combination. The concentration of the aqueous alkaline solution is preferably 5 to 30% by mass, particularly preferably 20 to 30% by mass. The concentration of aluminum dissolved in the alkaline aqueous solution is preferably 0.5 to 30% by mass. Etching with an alkaline aqueous solution is preferably performed at a liquid temperature of 25 to 90 ° C. for 1 to 120 seconds. Aluminum dissolution amount is 2-20g / m²And
[0023]
In general, an alkali etching process generates an unnecessary substance (smut) on the surface of the aluminum plate. In this case, phosphoric acid, nitric acid, sulfuric acid, hydrochloric acid, chromic acid, or two or more of them are used. It is preferable to remove the smut by performing a desmut treatment with a mixed acid containing an acid. The desmutting time is preferably 1 to 30 seconds. The liquid temperature is from room temperature to 70 ° C.
[0024]
The electrolytic surface roughening treatment is suitable for making a lithographic printing plate having excellent printability because it is easy to impart fine irregularities (pits) to the surface of the aluminum plate. The electrolytic surface roughening treatment is performed using direct current or alternating current in an aqueous solution mainly composed of nitric acid or hydrochloric acid.
By the electrolytic surface roughening treatment, craters or honeycomb-like pits having an average diameter of about 0.2 to 20 μm can be generated on the surface of the aluminum plate at an area ratio of 30 to 100%. The pits have the effect of improving the resistance to stains (non-stain resistance) and printing durability of the non-image area of the printing plate. In the electrolytic surface roughening treatment, an amount of electricity necessary for providing sufficient pits on the surface, that is, the product of current and energization time is an important condition. From the viewpoint of energy saving, it is preferable that sufficient pits can be formed with a smaller amount of electricity. In the present invention, the conditions for the electrolytic surface-roughening treatment are not limited and can be performed under general conditions.
[0025]
In a preferred embodiment of the lithographic printing plate support used for the lithographic printing plate of the present invention, an alkali etching treatment is further performed after the electrolytic surface-roughening treatment.
This alkali etching treatment is performed for the purpose of quickly removing smut components generated in the previous electrolytic surface roughening treatment. Aluminum dissolution amount is 0.05-5g / m²Is preferable. The composition, temperature, treatment time, and the like of the aqueous solution used for etching are selected from the ranges described above for the alkali etching treatment before the electrolytic surface roughening treatment.
[0026]
Furthermore, it is preferable to perform a desmut treatment. The conditions for the desmut treatment are selected from the above-described range for the desmut treatment after the alkali etching treatment before the electrolytic surface roughening treatment.
[0027]
Following the above roughening treatment and other treatments performed as necessary, an anodizing treatment is usually performed to increase the wear resistance of the surface of the aluminum plate to form an anodized film. Also in the present invention, it is preferable to perform anodizing treatment. The anodized film can be formed by immersing an aluminum plate as an electrode in an electrolytic solution and passing an electric current therethrough.
As currents to be communicated in the anodizing treatment, various waveform currents such as direct current alternating current are selected according to the purpose. Any electrolyte that forms a porous oxide film can be used as the electrolyte used in the anodizing treatment, and sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is generally used. . The concentration of these electrolytes can be appropriately determined depending on the type of electrolyte. The treatment conditions for anodization vary depending on the electrolyte used and cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 1 to 1. 60A / dm²A voltage of 1 to 100 V and an electrolysis time of 10 seconds to 5 minutes are suitable. The amount of anodized film formed by anodizing is usually 1 to 6 g / m.²Is preferred.
[0028]
After the anodizing treatment, a sealing treatment may be performed if desired. The sealing treatment is performed by a method of immersing the anodized aluminum plate in hot water or a hot aqueous solution containing an inorganic salt or an organic salt, a method of exposing it to a steam bath, or the like.
[0029]
Further, after the anodizing treatment, an interface control treatment such as a hydrophilic treatment may be performed if desired.
Examples of the interface control treatment include alkali metal silicates (for example, sodium silicate) disclosed in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734. Aqueous solution) method. In this method, the lithographic printing plate support is immersed in an aqueous sodium silicate solution or electrolytically treated. In addition, potassium fluoride zirconate disclosed in Japanese Patent Publication No. 36-22063, as disclosed in US Pat. Nos. 3,276,868, 4,153,461, and 4,689,272 are disclosed. A method of treating with polyvinylphosphonic acid is used.
[0030]
For the details of each process described in the above items, known conditions can be appropriately adopted. Further, the contents of the documents cited in this specification are cited as the contents of this specification.
[0031]
As described above, the surface of the aluminum plate on which the photosensitive layer is provided is subjected to a surface treatment including at least a roughening treatment, and the back surface is subjected to an alkali etching treatment and a desmut treatment. As shown in FIGS. 1 and 2, the alkali etching treatment and the desmut treatment produce a wood grain pattern or a streak pattern on the back surface. In the planographic printing plate of the present invention obtained by using this, the aluminum plate used It becomes possible to easily determine the rolling direction.
[0032]
The alkali etching treatment on the back surface can be carried out in the same manner as the alkali etching treatment for the surface on which the photosensitive layer is provided, and in particular, using an aqueous caustic soda solution having a pH of 13 or more, the aluminum dissolution amount is 0.1 to 5 g / m.²Is preferable.
The desmutting treatment on the back surface can be carried out in the same manner as the desmutting treatment for the surface on which the photosensitive layer is provided, but a method in which an acidic aqueous solution having a nitric acid concentration of 1% by mass or more is applied in a shower form is particularly preferable.
After the alkali etching treatment on the back surface and after the desmut treatment, it is preferable to perform a water washing treatment.
[0033]
The alkali etching treatment and desmut treatment on the back surface may be performed separately from the surface treatment on the surface on which the photosensitive layer is provided, but it is preferable to perform the same step in the same step because the number of processing steps can be reduced.
Examples of the method for performing the alkali etching treatment in the same step include a method in which an alkaline aqueous solution is sprayed on both sides of an aluminum plate by spraying, or a method in which the aluminum plate is immersed in an alkaline aqueous solution bath. Can be mentioned.
As a method for applying the desmut treatment in the same process, for example, a method in which acid is applied to both surfaces of an aluminum plate by spraying or the like can be mentioned.
Moreover, it is preferable to perform the water washing process after an alkali etching process and a desmut process in the same process. For example, a method of spraying water on both sides of an aluminum plate by spraying or the like can be mentioned.
[0034]
A lithographic printing plate support is obtained as described above. In order to obtain the planographic printing plate of the present invention, a photosensitive layer may be formed by applying a photosensitive agent to the surface and drying it. The photosensitive agent is not particularly limited, and those usually used for photosensitive lithographic printing plates can be used. A printing plate that can be attached to a printing press can be obtained by printing, developing, and gumming the image using a lith film. In addition, when a highly sensitive photosensitive layer is provided, an image can be directly printed using a laser.
[0035]
As the photosensitive agent, any photosensitive compound or composition thereof can be used as long as the solubility or swellability in the developer changes before and after exposure. Hereinafter, typical ones will be described.
[0036]
(A) Photosensitive layer comprising an o-quinonediazide compound
Examples of the photosensitive compound used in the positive photosensitive composition include an o-quinonediazide compound, and an o-naphthoquinonediazide compound is specifically exemplified.
As the o-naphthoquinonediazide compound, an ester of 1,2-diazonaphthoquinonesulfonic acid chloride and pyrogallol-acetone resin described in JP-B-43-28403 is preferable. Also preferred are esters of 1,2-diazonaphthoquinonesulfonic acid chloride and phenol-formaldehyde resins described in US Pat. Nos. 3,046,120 and 3,188,210. Other known o-naphthoquinonediazide compounds can also be used.
[0037]
A particularly preferred o-naphthoquinonediazide compound is a compound obtained by reacting a polyhydroxy compound having a molecular weight of 1,000 or less and 1,2-diazonaphthoquinonesulfonic acid chloride. When synthesizing this o-naphthoquinonediazide compound, the reaction is carried out so that the ratio of 1,2-diazonaphthoquinonesulfonic acid chloride is 0.2 to 1.2 equivalents relative to 1 equivalent of the hydroxyl group of the polyhydroxy compound. It is more preferable to make it react so that it may become a ratio of 0.3-1.0 equivalent. As the 1,2-diazonaphthoquinonesulfonic acid chloride, 1,2-diazonaphthoquinone-5-sulfonic acid chloride is preferable, but 1,2-diazonaphthoquinone-4-sulfonic acid chloride can also be used.
The obtained o-naphthoquinonediazide compound is a mixture of various substituent positions and introduction amounts of 1,2-diazonaphthoquinonesulfonic acid chloride, but all hydroxyl groups are 1,2-diazonaphthoquinonesulfonic acid esters. It is preferable that the ratio (content rate of what was completely esterified) to what was converted into is 5 mol% or more, and it is more preferable that it is 20-99 mol%.
[0038]
In addition, as a photosensitive compound acting positively without using an o-naphthoquinonediazide compound, for example, a polymer compound having an o-nitrocarbinol ester group described in Japanese Patent Publication No. 56-2696 is used. You can also. Furthermore, a combination system of a compound that generates an acid by photolysis and a compound having a —C—O—C— group or a —C—O—Si— group that is dissociated by an acid can also be used.
For example, a combination of a compound that generates an acid upon photolysis and an acetal or O, N-acetal compound (Japanese Patent Laid-Open No. 48-89003), a combination of an ortho ester or an amide acetal compound (Japanese Patent Laid-Open No. 51-120714). Gazette), a combination with a polymer having an acetal or ketal group in the main chain (Japanese Patent Laid-Open No. 53-133429), a combination with an enol ether compound (Japanese Patent Laid-Open No. 55-12995), an N-acyliminocarbon compound, (Japanese Unexamined Patent Publication No. 55-126236), a combination with a polymer having an orthoester group in the main chain (Japanese Unexamined Patent Publication No. 56-17345), and a combination with a silyl ester compound (Japanese Unexamined Patent Publication No. 60-10247) And a combination with a silyl ether compound (JP-A-6) -37549 and JP Sho 60-121446) and the like.
[0039]
The proportion of the photosensitive compound (including the combination system as described above) acting positively in the photosensitive composition of the photosensitive layer is preferably 10 to 50% by mass, and 15 to 40% by mass. Is more preferable.
[0040]
Although the o-quinonediazide compound alone can constitute the photosensitive layer, it is preferably used together with a resin soluble in alkaline water as a binder (binder). Examples of resins soluble in alkaline water include novolak resins, such as phenol-formaldehyde resins; m-cresol-formaldehyde resins, p-cresol-formaldehyde resins, m- / p-mixed cresol-formaldehyde resins, phenol / cresols ( Any of m-, p- and m- / p-mixtures) Mixed-cresol-formaldehyde resin such as formaldehyde resin; phenol-modified xylene resin; polyhydroxystyrene; polyhalogenated hydroxystyrene; Acrylic resins containing phenolic hydroxyl groups as disclosed in JP-A-51-34711; acrylic resins having sulfonamide groups described in JP-A-2-866; various resins such as urethane resins Of alkali soluble It may contain a molecular compound. The alkali-soluble polymer compound preferably has a weight average molecular weight of 500 to 20,000 and a number average molecular weight of 200 to 60,000.
[0041]
The alkali-soluble polymer compound is contained in a proportion of 70% by mass or less of the total composition. Furthermore, as described in U.S. Pat. No. 4,123,279, a phenol having a C 3-8 alkyl group as a substituent, such as t-butylphenol-formaldehyde resin and octylphenol-formaldehyde resin; Use of a resin obtained by polycondensation with formaldehyde is preferred in terms of improving the oil sensitivity of the image.
[0042]
The photosensitive composition can contain a cyclic acid anhydride for increasing sensitivity, a print-out agent for obtaining a visible image immediately after exposure, a dye as an image colorant, and other fillers.
Cyclic acid anhydrides are, for example, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy-Δ, as described in US Pat. No. 4,115,128.^Four-Tetrahydrophthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride.
By including 1 to 15% by mass of the cyclic acid anhydride with respect to the mass of the entire composition, the sensitivity can be increased up to about 3 times.
[0043]
Examples of the printing-out agent for obtaining a visible image immediately after exposure include a combination of a photosensitive compound that releases an acid upon exposure and an organic dye that can form a salt.
Specifically, for example, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128, JP-A 53-36233, JP-A 54-74728, JP-A 60-3626, JP-A 61-143748, JP-A 61-151644, JP-A 63- The combination of the trihalomethyl compound and salt forming organic dye which are described in 58440 is mentioned.
[0044]
As the image colorant, other dyes than the above-mentioned salt-forming organic dyes can also be used. Suitable dyes including salt-forming organic dyes include oil-soluble dyes and basic dyes.
Specifically, for example, oil yellow # 101, oil yellow # 103, oil pink # 312, oil green BG, oil blue BOS, oil blue # 603, oil black BY, oil black BS, oil black T-505 (whichever Also available from Orient Chemical Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI 42555), Methyl Violet (CI 42535), Rhodamine B (CI 45170B), Malachite Green (CI 42000), and Methylene Blue (CI 522015). The dyes described in JP-A-62-293247 are particularly preferred.
[0045]
The photosensitive composition is used by being applied to the lithographic printing plate support obtained above as a solution by dissolving it in a solvent capable of dissolving the above components.
Solvents include, for example, ethylene dichloride, cyclohexanone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, toluene, ethyl acetate , Methyl lactate, ethyl lactate, dimethyl sulfoxide, dimethylacetamide, dimethylformamide, water, N-methylpyrrolidone, tetrahydrofurfuryl alcohol, acetone, diacetone alcohol, methanol, ethanol, isopropanol, diethylene glycol, dimethyl ether. These may be used alone or in combination.
The density | concentration (solid content) of each said component in a solution is 2-50 mass%. The coating amount varies depending on the application. For example, in the case of a photosensitive lithographic printing plate, the solid content is generally 0.5 to 3.0 g / m.²Is preferred. Photosensitivity increases as the coating amount decreases, but the physical properties of the photosensitive film decrease.
[0046]
The photosensitive composition can contain a surfactant, for example, a fluorosurfactant as described in JP-A-62-170950 in order to improve the coating property. The content of the surfactant is preferably 0.01 to 1% by mass of the total photosensitive composition, and more preferably 0.05 to 0.5% by mass.
[0047]
(B) Photosensitive layer comprising diazo resin and binder
Negative working photosensitive diazo compounds include diazonium salts disclosed in US Pat. Nos. 2,063,631 and 2,667,415 and reactive carbonyl groups such as aldol and acetal. A condensation product (so-called photosensitive diazo resin) of diphenylamine-p-diazonium salt and formaldehyde, which is a reaction product with an organic condensing agent having benzene, is preferably used.
Other useful condensed diazo compounds are described in JP-B-49-480001, JP-B-49-45322, JP-B-49-45323, and the like. Since this type of photosensitive diazo compound is usually obtained in the form of a water-soluble inorganic salt, it can be applied as an aqueous solution. In addition, an aromatic compound or an aliphatic compound having one or more phenolic hydroxyl groups, sulfonic acid groups, or both of the water-soluble diazo compound by the method described in Japanese Patent Publication No. 47-1167 A substantially water-insoluble photosensitive diazo resin, which is a reaction product of the reaction, can also be used.
The content of the diazo resin is preferably 5 to 50% by mass in the photosensitive layer. When the content decreases, the photosensitivity increases, but the stability over time decreases. The optimum diazo resin content is about 8-20% by weight.
[0048]
On the other hand, various polymer compounds can be used as the binder.
Among them, those having a functional group such as hydroxyl group, amino group, carboxyl group, amide group, sulfonamide group, active methylene group, thioalcohol group, and epoxy group are preferable. For example, shellac as described in British Patent 1,350,521, as described in British Patent 1,460,978 and US Pat. No. 4,123,276. Polymers containing hydroxyethyl (meth) acrylate units as the main repeating unit, polyamide resins described in US Pat. No. 3,751,257, described in British Patent 1,074,392 Phenol resin and polyvinyl acetal resin such as polyvinyl formal resin and polyvinyl butyral resin, linear polyurethane resin described in US Pat. No. 3,660,097, phthalated resin of polyvinyl alcohol, bisphenol An epoxy resin obtained from A and epichlorohydrin, Aminostyrene and polyalkylamino (meth) polymers containing amino groups such as acrylate, cellulose acetate, cellulose alkyl ethers, cellulose derivatives such as cellulose acetate phthalate.
[0049]
The composition comprising a diazo resin and a binder is further described in pH indicators such as those described in British Patent 1,041,463, US Pat. No. 3,236,646. Additives such as phosphoric acid and dyes can be contained.
[0050]
The film thickness of the photosensitive layer provided on the lithographic printing plate support is preferably from 0.1 to 30 μm, and more preferably from 0.5 to 10 μm. The amount (solid content) of the photosensitive layer is about 0.1 to about 7 g / m²Preferably, 0.5-4 g / m²It is more preferable that
[0051]
The lithographic printing plate is subjected to image exposure, and then a resin image is formed by processing including development by a conventional method. For example, in the case of a positive photosensitive lithographic printing plate having a photosensitive layer (A), it is described in US Pat. No. 4,259,434 and JP-A-3-90388 after image exposure. By developing with an alkaline aqueous solution, the exposed portion of the photosensitive layer is removed, and a printing plate is obtained.
In the case of a negative photosensitive lithographic printing plate having a photosensitive layer (B) composed of a diazo resin and a binder, it is described, for example, in US Pat. No. 4,186,006 after image exposure. By developing with such a developing solution, the unexposed portion of the photosensitive layer is removed, and a printing plate is obtained. Further, in the case of negative photosensitive lithographic printing plates described in JP-A-5-2273 or JP-A-4-219759, as described in these publications, an alkali metal silicate is used. It can be developed with an aqueous solution.
[0052]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
1. Production of lithographic printing plates
Example 1
Using a twin roll type continuous casting machine, an aluminum cast plate having a thickness of 7 mm was formed, then cold-rolled to a thickness of 2 mm, heat-treated (annealed) at 480 ° C., and then a thickness of 0 Cold rolling and straightening were performed so that the thickness was 24 mm, and a JIS 1050 material was formed.
On the cast upper surface of the obtained aluminum rolled plate, alkali etching treatment, desmut treatment, electrochemical surface roughening treatment and anodizing treatment are sequentially performed, while the lower surface of the cast is subjected to alkali etching treatment and desmut treatment, and a lithographic plate A printing plate support was obtained. The alkali etching treatment and desmut treatment on both sides were performed simultaneously.
The alkali etching treatment on the back side uses a caustic soda aqueous solution with a pH of 13, and the aluminum dissolution amount is 1 g / m.²As given. In the desmutting treatment on the back surface, an acidic aqueous solution having a nitric acid concentration of 1% by mass was showered to remove the smut generated by the alkali etching treatment. In addition, after each process, the water washing process was performed, respectively.
A photosensitive layer was provided on the surface of the obtained lithographic printing plate support which had been subjected to a roughening treatment, to obtain a lithographic printing plate of the present invention. A wood grain pattern appeared on the back side of the obtained lithographic printing plate.
[0053]
(Reference example 1)
  A lithographic printing plate of the present invention was obtained in the same manner as in Example 1, except that the cast aluminum upper surface of the obtained aluminum plate was the back surface. A wood grain pattern appeared on the back side of the obtained lithographic printing plate.
[0054]
(Reference example 2)
  After forming a 15 mm thick aluminum rolled plate using a twin belt type continuous casting machine and a hot rolling mill, and then cold rolling to a thickness of 2 mm and heat-treating (annealing) at 400 ° C. Then, cold rolling and straightening were performed so that the thickness was 0.24 mm, and a JIS 1050 material was formed.
  Using the cast aluminum lower surface of the obtained aluminum rolled plate as the back surface, the same treatment as in Example 1 was carried out on both sides to provide a photosensitive layer to obtain a lithographic printing plate of the present invention. A streak-like pattern appeared on the back surface of the obtained lithographic printing plate.
[0055]
(Reference example 3)
  Except for the casting upper surface of the obtained aluminum rolled plate as the back surface,Reference example 2The planographic printing plate of the present invention was obtained by the same method as above. A streak-like pattern appeared on the back surface of the obtained lithographic printing plate.
[0056]
(Comparative Example 1)
A lithographic printing plate was obtained in the same manner as in Example 1 except that the back surface was not subjected to alkali etching treatment and desmut treatment.
[0057]
(Comparative Example 2)
A lithographic printing plate was obtained by the same method as in Example 2 except that the back surface was not subjected to alkali etching treatment and desmut treatment.
[0058]
(Comparative Example 3)
A 500 mm thick cast soul is formed by DC casting, and the surface of the resulting ingot is scraped on average by 10 mm using a surface grinder, then heated at 550 ° C. for about 5 hours, soaking treatment Was given. When the temperature drops to 400 ° C., it is hot-rolled to a thickness of 3 mm, further heat-treated at 500 ° C. using a continuous annealing machine, and then cooled to a thickness of 0.24 mm. JIS 1050 material was formed by hot rolling.
With one side of the obtained aluminum rolled plate as the back side, each treatment was performed on both sides by the same method as in Example 1 to provide a photosensitive layer to obtain a lithographic printing plate.
[0059]
(Comparative Example 4)
A lithographic printing plate was obtained by the same method as in Comparative Example 3 except that the back surface was not subjected to alkali etching treatment and desmut treatment.
[0060]
2. Visibility of the pattern on the back
The visibility of the pattern on the back surface of the planographic printing plate of each example and comparative example was evaluated.
`` Good '' if the pattern is clear and the rolling direction of the aluminum rolled sheet can be discriminated, `` Slightly inferior but good '' if the pattern is slightly unclear but the rolling direction is identifiable, and the pattern is unclear and the rolling direction is difficult to distinguish “Bad”.
[0061]
  The results are shown in Table 1.
  Since the lithographic printing plate of the present invention has a grain-like pattern or streak-like pattern on the back side, it can be seen that it is excellent in visibility and that the rolled direction of the used aluminum rolled sheet can be easily distinguished (Example 1).Reference examples 1 to 3).
  On the other hand, a lithographic printing plate having no wood grain pattern or stripe pattern on the back surface is inferior in visibility (Comparative Examples 1 to 4).
[0062]
[Table 1]

[0063]
【The invention's effect】
Since the lithographic printing plate of the present invention has a photosensitive layer on one side and a wood grain pattern or streak pattern on the other side, it is easy to determine the rolling direction of the used aluminum rolled plate. There is no misrecognition of the vertical and horizontal directions during work and installation to the printing press, and it is easy to handle.
In particular, as an aluminum plate used for a lithographic printing plate support, an aluminum rolled plate obtained by twin roll continuous casting and cold rolling, or an aluminum rolled plate obtained by twin belt continuous casting, hot rolling and cold rolling is used. When a wood grain pattern or stripe pattern is provided by alkali etching treatment and desmut treatment, the number of manufacturing steps can be reduced, which is extremely useful.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of the back surface of a lithographic printing plate of the present invention having a grain pattern on the back surface.
FIG. 2 is a diagram showing an example of the back surface of the lithographic printing plate of the present invention having a streaky pattern on the back surface.
[Explanation of symbols]
1 Planographic printing plate of the present invention having a grain pattern on the back side
2 Planographic printing plate of the present invention having a streak pattern on the back side

Claims (3)

A method for producing a lithographic printing plate support, which comprises subjecting an aluminum rolled plate obtained by twin roll continuous casting and cold rolling to surface treatment to produce a lithographic printing plate support,
The lithographic printing plate support is a lithographic printing plate support used for a lithographic printing plate in which a photosensitive layer is provided on the surface to be roughened,
Applying at least a roughening treatment to the upper surface of the aluminum rolled plate when casting;
A method for producing a support for a lithographic printing plate, comprising a step of subjecting a lower surface during casting of the aluminum rolled plate to an alkali etching treatment and a desmut treatment to provide a grain pattern. The alkali etching treatment is performed using an aqueous caustic soda solution having a pH of 13 or more so that the aluminum dissolution amount is 0.1 to 5 g / m ² ,
The method for producing a lithographic printing plate support according to claim 1, wherein the desmutting treatment is performed by a method in which an acidic aqueous solution having a nitric acid concentration of 1% by mass or more is applied in a shower form. The roughening treatment is a treatment in which an alkali etching treatment, a desmut treatment, an electrochemical roughening treatment and an anodizing treatment are performed in this order,
The lithographic printing according to claim 1 or 2, wherein the alkali etching treatment and the desmut treatment in the roughening treatment and the alkali etching treatment and the desmut treatment in the step of providing the wood grain pattern are simultaneously performed. A method for producing a plate support.

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