JPS6167863A - Photosensitive lithographic printing plate - Google Patents

Abstract

PURPOSE:To prevent the scratch of the rear side of a support during manufacture and to keep a photosensitive layer on the front side from taking scratches during handling by forming the coating layer of a hydrophobic high-molecular compound on the rear side. CONSTITUTION:A grained layer 3 and a photosensitive layer 4 are successively formed on one side of an Al support 1, and the coating layer 2 of a hydrophobic high-molecular compound having <=0.1mm thickness is formed on the other side. When a printing plate is manufactured, the scratch of the rear side of the support is prevented, and when the plate is superimposed and handled, the photosensitive layer takes hardly scratches. An edge is not nicked during cutting, and the sticking of condensate can be prevented during rapid cooling.

Description

Detailed Description of the Invention (1) Object of the Invention (Field of Industrial Application) The present invention relates to a photosensitive lithographic printing plate, and more specifically to a coating layer of Branudik provided on the back side of a photosensitive lithographic printing plate. This invention relates to a lithographic printing plate characterized by the following characteristics:

(Prior art) Conventionally, aluminum has been used as a support for offset printing plates for medium to high printing durability, that is, offset lithographic printing plates for double printing. Difficulty in deformation, resistance to rust,
This is a well-known fact along with useful characteristics such as poor wettability with water. Furthermore, in order to improve the hydrophilicity of the non-image areas, it is a known technique to perform physical or chemical polishing to form a grained shape.

However, it is also known that there are various disadvantages due to the use of aluminum.

For example, the occurrence of scratches on the photosensitive layer during manufacturing, the occurrence of scratches on the surface of the photosensitive layer due to the transfer of the scratches, and the "contouring" between the back surface of aluminum and the photosensitive layer when stacking printing plates is transported or handled. Occurrence of scratches, occurrence of blade spillage when cutting printing plates from which paper has been removed, transfer failure of the photosensitive layer to the aluminum surface when stacking printing plates from which the mount has been removed, and condensation due to temperature changes (rapid cooling). At present, adhesion of water to the photosensitive layer during development, and contamination and failures caused by this, have become a practical problem.

On the other hand, printing plate base materials made by laminating aluminum foil or the like on volimer bene are also known, but they only have performance for the field of so-called light printing, and their printing durability and print quality are 8.
It is not satisfactory in terms of durability, dimensional stability, etc.

(Object of the Invention) As a result of intensive research aimed at improving these drawbacks, the present invention has developed a lithographic printing plate in which a photosensitive composition is provided on an aluminum support having rough grains on one side, the opposite side of the photosensitive layer. By providing a coating layer with a thickness of 100 μm or less as the outermost shell layer on the support, these drawbacks can be improved.

That is, the object of the present invention is to use aluminum as a support,
An object of the present invention is to provide a photosensitive lithographic printing plate which can prevent generation of backing when producing a photosensitive lithographic printing plate having a photosensitive layer on one side thereof.

Another object of the present invention is to provide a lithographic printing plate in which the photosensitive layer is less likely to be damaged when the printing plates are stacked and handled.

Another object of the present invention is to provide a photosensitive lithographic printing plate that is less likely to be damaged during transportation, even when the gold paper is removed, and that reduces the risk of blade spillage during cutting. There is a particular thing.

Another object of the present invention is to provide a photosensitive lithographic printing plate to which condensed water is less likely to adhere even during rapid cooling.

(2) Structure of the Invention The object of the present invention is to provide a photosensitive lithographic printing plate having a photosensitive layer on the grained surface of an aluminum support having grains on one side. This is achieved by a photosensitive lithographic printing plate characterized by having a coating layer with a thickness of 100 μm or less on the outermost layer on the opposite side.

Hereinafter, the structure of the photosensitive lithographic printing plate of the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of a photosensitive planographic printing plate according to the present invention. In the figure, 1 is an aluminum plate, 2 is a coating layer, 3 is a grained layer, and 4 is a photosensitive layer.

The aluminum plate for No. 1 may be an aluminum plate that is generally known for use in printing plates, and its thickness should be such that it has sufficient stiffness, resistance to dents, and ease of handling when used as a printing plate material for No. 1 stamps. On the other hand, it is preferable that the thickness be within a certain range suitable for various items such as resistance to scratches during handling and transfer of the photosensitive layer to the back surface during lamination.
A thickness of 0.15111 to 1 m is generally preferred. The thickness of the aluminum plate is particularly preferably 0.
．． 0.50 mm from 20 bets, more preferably 0.23
0.3L) dish.

The coating layer No. 2 has mechanical strength (5) that satisfies the purpose of the present invention.
Any material may be used as long as it has a JiS hardness of 1 to 100 (preferably 1 to 100). In addition, the chemical properties of the photosensitive lithographic printing plate, such as various solutions used in processing and printing ink, and the lithographic printing plate made from it are preferably made of a material that is not susceptible to at least chemicals with which it may come into contact. Examples of such a covering layer include a cell opening layer, a cellulose G conductor layer, and a plastic layer. A preferred example is a plastic layer.

As the plastic coating layer, plastics insoluble in water or alkaline aqueous solutions, such as polyethylene, polypropylene, borinutylene, polyester, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polybutadiene, and polyurethane, are preferably used.

Various methods can be used to coat the aluminum plate with Branutik coating WI. For example, acetone,
A method of dissolving plastic in a suitable solvent such as dioxane, cellosols, DMF, etc., applying and drying; For example, a method of adhering a plastic film using a suitable adhesive such as epoxy, synthetic rubber, or acrylic, e.g. ,
Examples include a method of covering by thermocompression bonding a laminating film of polyethylene, polypropylene, polyvinyl chloride, or the like. The surface of the aluminum support on the side covered by the coating layer may be smooth or rough, but a smooth surface is preferred. The thickness of the coating layer is preferably in the range of 1107z to 100 μm.

The grain No. 3 includes grains obtained by performing a graining process known as a lithographic printing plate for nail stamps. Examples include grains that have been subjected to ball polishing graining treatment, flage polishing graining treatment, electrolytic polishing graining treatment using a hydrochloric acid bath or nitric acid bath, or a combination of these graining treatments.

The effect of improving the ease of scratching during the production of photosensitive planographic printing plates is as follows:
It is more noticeable on those with a grained surface than on those with a slim aluminum surface. Further, the effect of the present invention is particularly large on a support having a grained surface treated with five electrolytically polished grains. A conventionally known graining method is applied to the electrolytic grain graining method. For example, after degreasing an aluminum plate, a current density of 20 to 2
00 A/dm2, temperature 20~30℃, time 10~
Electrolytic polishing treatment is performed within a range of 170 seconds.

The effect of the present invention is interesting because it is remarkable in terms of the moss on the surface subjected to the graining treatment by electrolytic polishing, such as ease of scratching, staining caused by printing, etc. The reason for this is thought to be due to the dense grained surface structure of electrolytic polishing or the fine grained structure, but the causal relationship is not clear.

When such a grained surface is used as a lithographic printing plate material for future use, it is generally anodized for purposes such as printing durability, ease of printing, and water retention. The same applies. For example, anodization treatment is performed with an acid such as sulfuric acid or linic acid at a concentration of 10 to 50% and a current density of 1 to 10 A/dm2.

The photosensitive layer No. 4 includes those known as photosensitive layers of negative-type and positive-type photosensitive lithographic printing plates. That is, the photosensitive composition constituting the photosensitive layer includes an 0-quinonediazide compound and an alkali-soluble resin in the case of a positive type, and a diazonium salt and a polymer compound containing a hydroxyl group in the case of a negative type.
Photopolymerizable compositions, photocrosslinking compositions, etc. are used.

The 0-quinonediazide compound is m-cresol formalin novolak resin. - Naphthoquinonediazide sulfonic acid ester, 0-naphthoquinonediazide sulfonic acid ester of pyrogallol acetone resin, 0-naphthoquinonediazide sulfonic acid ester of resorcin benzaldehyde resin, 0-naphthoquinonediazide sulfonic acid ester of pyrogallol acetone resin, etc. - Naphthoquinonediazide compound and alkali-soluble resin, such as novolac resin, styrene maleic anhydride resin, acrylic powder resin, p-human O
Xynuthylene resin and the like are preferably used.

Examples of dianium salt compounds include inorganic salts such as 1-I'-organic nulphonic acid salts of p-diazodiphenylamine or hexafluorophosphoric acid, and organic nulphonic acid salts or inorganic salts of 3-methoxy-4-diazodiphenylamine. Photosensitive compositions containing hydroxy groups include homopolymers such as hydroxyethyl methacrylate and hydroxymemole acrylate, or copolymers with other monomers such as acrylonitrile and acrylic I'i2, p-hydroxyphenylmethacrylamide, and p-hydroxynaphthylmethacrylate. Homopolymers such as acrylamide or acrylonitrile,
Copolymers with other hexamers such as acrylic acid are preferably used.

Regarding photosensitive compositions containing these diazonium salts,
With the rapid increase in prefecture level 5#: The occurrence of stains, which is thought to be caused by the adhesion of condensed water, differs markedly depending on the presence or absence of a coating layer, which is an interesting phenomenon.

Examples of the photopolymerization composition and photocrosslinking composition used in the photosensitive layer 4 include polyester chains containing α and β unsaturated ketones, polyamides, polycarbonates, acrylic acids,
Examples include photosensitive acid compounds such as polyamide nuthylene and polyvinyl-p-andbenzoate.

The photosensitive composition can be prepared in a suitable solvent, such as medyl cellosol 7.
, ethyl cellosolve, cellosolve acetate, and other cellosolves, dioxane, acetone, ethylene dichloride, dimethyl formamide, dimethyl nulphoxide, etc., and coated on a support with a roll coater, bead coater, etc., and dried to form a photosensitive lithographic plate. Print version.

The thickness of the photosensitive layer is 0.5 in the case of lithographic printing plate material for the mold part.
pm to 5.0 pm (5 mg/film weight)
dm2 to 50 strokes/dm2), the effect of the backside coating becomes noticeable. Moreover, more preferably 1.0 μm
to 30μm (1019/drr1 in coating film weight)
2 to 30 Mg/dm2).

If necessary, a mat M can be provided on the photosensitive layer in order to improve vacuum adhesion, blurring, etc.

The photosensitive lithographic printing plate of the present invention having such five structures can be subjected to exposure and development treatment by a conventionally known plate-making method, and then used as a lithographic printing plate.

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these.

Example 1 After degreasing a coiled 2S aluminum plate with a thickness of 25 tm, it was soaked in a 0.3 mol/l nitric acid aqueous solution at 30
Electrolytic polishing surface roughening treatment was performed at .degree. C. for 30 seconds at alternating current and electrolytic density of 50 A/dm.sup.2. Next, 5% caustic soda water bath tI
Denumatization was carried out for 10 seconds at 60'Q in I, and further at 20°Q in a 20% sulfuric acid solution at 3 A/dm2.
After anodizing for 1 minute, it was washed with water, dried, and sanded.

Next, the back side of the grained aluminum plate was coated with a thickness of J60.
1 Im protection tape #622C (manufactured by Sekinui Chemical Industry Co., Ltd.) was applied with a heated roller (100'Q, 0.
2 seconds) 1000 m of grained aluminum coils were crimped and laminated on the back side. Grain depth Ra of the aluminum grain (German standard) = 0.65μ
The amount of m1 anodic oxide film was 27Q/dm2.

Next, apply the following photosensitive liquid A to a tension of 13 with a double roll coater.
Coat and dry at 0 kg (100 (I normal width)) (90'Q,
3 minutes).

The rollers used to route the aluminum plate were 30 chrome-plated rollers and 20 rubber rollers (material: SBR).
rubber).

Photosensitive liquid A ・O-naphthoquinonediazide-5-nurphonic acid ester compound CIII ratio of m-cresol novolak resin 2
5 mole%) 100 parts by weight, phenol/cresol mixed novolac resin (JP-A-1986-
Compound described in Publication No. 57841, Example 1) 350 portions @2-trichloromethyl-5-[β-(21-benzofuryl)vinyl)-1,3,4-oxadiazole
30 parts by weight of Victoria Air Pull-BOH 10 parts by weight 0-naphthoquinonediazide-5-nurphonic acid ester compound of p-octylphenol phenol resin 5 parts by weight ethyl cellosolve 2300 parts by weight Next, the photosensitive lithographic printing plate was cut using a rotary cutter. The sheets were cut into lengths of 800 m and packaged in bundles of 50 sheets.

Next, the bundle was cut into a size of 400 pieces x 500 m blades, but the cutting did not occur even after cutting more than 50,000 times.

Next, the photosensitive lithographic printing plate was subjected to exposure and development treatment in a conventional manner to obtain a lithographic printing plate. When the printing plate was observed, scratches and burrs, which were commonly seen in the past, were not found in the resin or grain areas. The same was true for the back side.

Furthermore, when the printing plate was attached to a printing machine and printed, a large number of good prints were obtained without defective inkling such as scratches and stains in non-image areas that were commonly seen in the past. .

Comparative Example 1 A 28 aluminum plate with a thickness of 0.10 m was used instead of the 28 aluminum plate with a thickness of 0.25 yax in Example 1, and the same material was used instead of the protective tape #622C on the back side of the aluminum. A manufacturing evaluation was performed using the same tape as in Example 1 using a tape having a thickness of 150 μm. As a result, after about 30,000 sheets, volima bene adhered to the cutting blade, causing trouble.

At the same time, the blade was chipped. Furthermore, in printing,
I was not able to obtain a product that satisfied me with the quality of the finish.

Particularly in color printing, discoloration occurred.

Comparative Example 2 After carrying out the electrolytic polishing and graining treatment in the same manner as in Example 1, the photosensitive liquid was applied and dried in the same manner as in Example 1 without laminating the protective tape on the back surface of the aluminum plate. When observing a total of 20 sheets, two sheets coated with a photosensitive layer every 100 m, there were 100 to 100 dot-like scratches of about 5 to 20 μm on the widthwise edges of the aluminum plates.
200 scratches/m2, and 20 to 30 knot-shaped scratches/m2 with a width of 2 to 5 μm and a length of 1 to 30 were observed. In particular, knot-shaped scratches were easily observed visually.

Comparative Example 3 Instead of the 28 aluminum plate with a thickness of 025 in Example 1, a 28 aluminum plate with a thickness of 010 was used,
Further, the photosensitive layer was applied and dried in the same manner as in Example 1 without laminating the protective tape on the back surface.

When the surface coated with the photosensitive layer was observed in the same manner as Comparative Example 2, 5
Point-like scratches of ~10 μm and width of 2 to 5 μm.

The number of leg-shaped wounded soldiers with a length of 1 to 3 crIL was reduced to about one-fifth compared to Comparative Example 2.

Example 2 One anodizing treatment was carried out as in Example 1, except that instead of the electrolytic polishing roughening treatment in nitric acid aqueous solution in Example 1, graining treatment (brush polishing method) vk was performed using a nylon brush. And lamination processing was performed.

The grain depth Ra of the aluminum grain was 0.66 μm, and the amount of anodic oxide film was 26.5897 m2.

Next, a photosensitive liquid was applied and dried in the same manner as in Example 1. Observations were made in the same manner as in Comparative Example 2.

In particular, no scratches were observed.

Comparative Example 4 A photosensitive lithographic printing plate material was produced in exactly the same manner as in Example 2, except that the lamination of the protective tape on the back side of the aluminum plate in Example 2 was not performed. Similar to Comparative Example 2, when observing the surface coated with the photosensitive layer, it was found that there were about 5 to 20 point-like scratches on the widthwise edges of the aluminum plate at a rate of 30 to 60 scratches/m2 and a width of 2 to 5 μm. , length 1~
Five to 10 3cvL slimy wounds/m2 were observed.

Example 3 Coating and drying were carried out in the same manner as in Example 1, except that the following photosensitive liquid B was used instead of the photosensitive liquid in Example 1.

Photosensitive solution B ・Hexafluorophosphate (molecular weight Mw
: 2400) 6 parts by weight p-hydroxymethacrylamide; acrylonitrile; ethyl acrylate; methacrylic acid (molar ratio 8:24:
60:8) copolymer (molecular weight Mw: 6.0
1 x 10') 100 parts by weight Victoria Buy Your Blue BOH (manufactured by Hojurikiya Chemical Co., Ltd.) 3 parts by weight 2 parts by weight of tricresyl phonufate 1000 parts by weight of methylseronulp Same as in Example 1 The blade was cut to a size of 400 am x 500 yen, but no chipping occurred even after cutting the blade more than 50,000 times. Further, when the coated surface of the photosensitive layer was observed, no scratches or the like were found.

Next, 50 pieces of paper measuring 400 wm x 500 mm were packed in moisture-proof paper in a room with a temperature of 25°C and humidity of 85%, and left in a room with a temperature of 5"00 for about 1 hour, and then heated to a temperature of 50°C. We repeated the temperature change experiment three times by leaving the sample in room C for about an hour (assuming a drastic temperature change from outside temperature to room temperature in winter).Next, we removed the packaging and carried out normal exposure. After development, a printing test was performed using a printing machine to check the ease with which stains appeared.The processing agent and equipment used are shown below.

Automatic processor: Sakura PS version processor "PSP860"
Image solution: Sakura PS plate developer “8DN-21” printing
Machine: Heidel GTO Printing ink: TOYO Ultra King Red” Table 1 shows the results of the presence or absence of stains.

Comparative Example 5.6 When a film was not laminated on the back side of the aluminum in Example 3 (Comparative Example 5), a film was not laminated on the nose side of the aluminum in Example 3, and the conventional mounting paper (JP-A-Show A temperature change experiment was conducted in the same manner as in Example 3 for both samples (Comparative Example 6) in which a polyolefin-based polymer-added interleaving paper described in No. 57-99647 was used (Comparative Example 6). The results are shown in Table 1.

Table 1 [Note] In Table 1, O means “no stain” and × means “stain occurs”
, Δ indicates "partial staining".

As is clear from Table 1, the printing plates of the present invention with a plastic film laminated on the back side do not show stains due to moisture adsorption, even when subjected to rapid temperature changes, and do not show stains due to moisture adsorption, which occurs in the past. It can be said that it is a stable printing version.

Example 4 In place of the protective tape $6220 in Example 1 and 3, vinyl chloride copolymer was used. -”Vinylite VY
Apply a cyclohexanone solution (20% by weight) of NS-3'' (manufactured by Bakelite) with a double roll coater.
The test was conducted in the same manner as in Example 1 except that drying was performed. (The thickness of the plastic layer was 20 μm.) As a result, good results similar to those in Example 1 were obtained. (3) Effects of the Invention The photosensitive lithographic printing plate of the present invention has the following effects. .

■ The occurrence of authenticity during manufacturing is prevented.

■ The photosensitive layer of photosensitive printing plates and lithographic printing plates made from them is 1° less likely to be scratched when stacked and handled ■ Photosensitive printing plates without backing paper are less likely to be scratched during transportation, etc. In addition, the blade spillage during cutting is improved.

■ Even during rapid cooling, condensed water is difficult to adhere to.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a photosensitive lithographic printing plate of the present invention. 1...-Aluminum plate 2...Coating layer 3
... Grain layer 4 ... Photosensitive layer agent Patent attorney Field 1) Mother-in-law 1-m-Aluminum plate 2-11 irregular cover layer 3---#@man ゛4 ---A#J row

Claims (3)

[Claims] (1) In a photosensitive lithographic printing plate having a photosensitive layer on the grained surface of an aluminum support having grains on one side, the outermost layer on the side opposite to the surface having the photosensitive layer of the support has a thickness of 100 μm. A photosensitive lithographic printing plate characterized by having the following coating layer. (2) The thickness of the aluminum support is from 0.15 mm to 1
2. The photosensitive planographic printing plate according to claim 1, wherein the photosensitive lithographic printing plate has a diameter of mm. (3) The photosensitive lithographic printing plate according to claim 1, wherein the coating layer is made of a hydrophobic polymer compound.