JPS6161996B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a lithographic printing plate for proofing.

Conventionally, PS plates have been mainly used as lithographic printing plates for proofing. As is well known, most PS plates are based on aluminum plates, and the surface of the aluminum plate is roughened mechanically, chemically, or electrically, and depending on the application, anodizing and hydrophilic treatments are also applied. After applying, a photosensitive agent layer is provided,
It's expensive. On the other hand, paper, synthetic resin sheets, aluminum foil, and composites of these and paper have been proposed as inexpensive lithographic printing plates (for example, in JP-A-53
-Refer to Publication No. 36302), although it is used in light printing, it is used as a proof plate for heavy printing because of its tone reproducibility,
They lack dimensional stability, water retention, etc., and the material is thin, causing dents and scratches during plate-making and printing operations.Therefore, these plates are not used as lithographic printing plates for proofreading. . For this reason, the expensive PS version is intentionally used. The expenses required for proof printing are not usually included in the printing cost, so in order to reduce the cost of the PS plate material, the photoresist film of the proof printing plate is removed, re-polished, and further exposed to light. In reality, efforts have been made to reuse the aluminum plate as a lithographic printing plate for proofreading after applying a coating agent.

In addition, when performing proof printing and main printing using PS plates, there are differences in the printing machine, type of ink, printing speed, etc. between the proof printing and main printing, so even if the same plate is used for printing, the proof printing It is difficult to make the finish of the actual printing the same as that of the actual printing. This also applies to offset printing. Offset printing, as is well known, is a method in which printing ink is deposited on an image formed on an original plate and transferred under pressure from a blanket to paper. In this method, the final paper image is formed to be thicker than the image on the original plate. This tendency is particularly noticeable in offset rotary presses that print at high speeds because highly fluid inks are used. However, offset rotary presses have advantages such as high production speed, being able to be processed or shipped immediately after printing, and being able to easily print on low-grade paper, so their use tends to increase more and more frequently. In addition, demand for multicolor printing is increasing, and quality requirements are also increasing.

The original purpose of multicolor printing proofs is to test print the original plate, which would have faithfully reproduced the manuscript, to confirm to the customer whether the desired tone has been reproduced. As a general rule, the printer should refer to the proof print that has been approved by the orderer and print it as close as possible.
The mission of proof printing is therefore critical.

For this reason, when performing multi-color printing using an offset rotary press or the like, efforts have been made to make the final print close to the same finish as the proof print. For example, by using a hard packing plate cylinder, by using a blanket (JISA-77) with high surface hardness, etc., to minimize the thickening of halftone dots and making it look like a film original plate, or by changing the exposure amount during the plate making stage of the printing original plate. Attempts have been made in advance to narrow the halftone dots using methods such as the following. However, the former attempt
The dot thickening from the midtones to the shadow areas is not resolved and is still unsatisfactory, and the latter attempt is unstable in terms of tone reproduction, especially color balance. At present, attempts to make the actual printing as close to the same finish as the proof printing have ended in failure.

In addition, from the completely opposite perspective, we make the halftone dots on the proof print thicker and print the proof print to the extent that we think that it will look like this if we print the final print. Attempts have also been made to approximate the quality of the finish. However, in proof printing, if a naphthoquinone derivative-based decomposable photosensitizer is used to make a positive proof plate directly from a positive film, it is impossible to make halftone dots thicker than in the film. In addition, attempts have been made to make the halftone dots as thick as possible by using a blanket (JISA-74) with a low surface hardness for proof printing, but since the original proof printing plate is fixed directly on a surface plate (iron plate), hard parts are used. It is the same as the king version body style, and the expected effect is not obtained.

As described above, at present, it is difficult to achieve the same level of finish between the final printing and the proof printing, and the current situation is that many problems and troubles have been encountered.

In view of the current situation, the inventors of the present invention have conducted extensive research in order to develop a lithographic printing plate for proofing that can produce proofs with the same level of finish as the actual printing with simple operations and is inexpensive. It has been found that a proofing lithographic printing plate according to the present invention can achieve the intended purpose of the present invention. The present invention was completed based on this knowledge.

That is, the present invention comprises: (1) a photosensitive layer, (2) an aluminum foil whose rough surface is anodized to an average depth of 0.2 to 0.45 μm, (3) a thermoplastic synthetic resin layer, and (4) an adhesive strength of 50 to 0.45 μm. The present invention relates to a lithographic printing plate for proofreading, characterized in that an adhesive layer having a thickness within the range of 250 g/25 mm, and (5) a support made of a metal plate are sequentially laminated.

When proof printing is performed using the proofing planographic printing plate of the present invention, the quality of the proof printing can be made comparable to that of the final printing performed later. What is particularly noteworthy is that when performing final printing, it is sufficient to use the same film original plate as the proof printing original plate, and no special printing equipment or printing technology is required. Conventionally,
In order to make the finishing quality of the final printing the same as that of the proof printing, special printing equipment or printing technology is required for the final printing, and even in such cases, it is necessary to make the finishing quality of the final printing the same as that of the proof printing. It was difficult to maintain the same level. In contrast, in the present invention, the proof print obtained using the above-mentioned proofing planographic printing plate has the same level of finish as the main print obtained without the need for special printing equipment or printing technology. This is possible. In addition, the lithographic printing plate for proofreading of the present invention has excellent properties such as tone reproducibility, dimensional stability, and water retention, and also has high physical strength, so there is no need to worry about dents or scratches during plate-making and printing operations. It is also excellent in terms of performance and operation. In addition, the proofreading lithographic printing plate that has been proofread has a photosensitive layer,
The aluminum foil, the thermoplastic synthetic resin layer, and the adhesive layer can be easily peeled off from the support, and the photosensitive layer, the aluminum foil, the thermoplastic synthetic resin layer, and the adhesive layer can be easily laminated on the support. Therefore, the support can be used repeatedly and is economically superior.

The lithographic printing plate for proofreading of the present invention consists of a photosensitive layer, an aluminum foil whose rough surface is anodized to an average depth of 0.2 to 0.45 μm, a thermoplastic synthetic resin layer, an adhesive layer, and a support. .

As the photosensitizer constituting the photosensitive layer, a wide variety of conventionally known photosensitizers can be used, such as naphthoquinone (1,
2) In addition to diazide(2)-sulfonic acid esters, solvent-soluble diazotides combined with various sulfonates and borofluorides, p-azidobenzophenone 4,
Examples include 4'-diazidochalcone, 2,5-di(4'-azidobenzal)cyclohexanone, 1-azidopyrene, and 4,4'-diazidostilbene.

The aluminum foil of the present invention is one in which one surface of the aluminum foil is roughened with an average depth of 0.2 to 0.45 μm, and the roughened surface is anodized. The method for forming a rough surface and the method for anodizing will be described later. As the aluminum foil used, a wide variety of known aluminum foils can be used, but the thickness is usually 6 to 100 mm.
Aluminum foil with a thickness of 15 to 80 μm is particularly preferred from the viewpoint of prevention of pinholes during formation of a rough surface, printing durability, etc.

As the thermoplastic synthetic resin constituting the thermoplastic synthetic resin layer, a wide variety of conventionally known thermoplastic synthetic resins can be used, and specific examples include polyethylene terephthalate, polypropylene, polyethylene, polycarbonate, cellulose acetate, polystyrene, polyvinyl chloride, synthetic paper, etc. Of these, polyethylene terephthalate, polypropylene, and synthetic paper are preferred. The thickness of the resin layer is not particularly limited and can be appropriately selected within a wide range, but is usually about 20 to 100 μm, preferably 30 to 80 μm.
The layer thickness is preferably m.

The adhesive that makes up the adhesive layer has adhesive strength.
Any known material can be used as long as it falls within the range of 50 to 250 g/25 mm. Specifically, such adhesives include self-crosslinking acrylic adhesives, such as Polysik 1001-S (trademark, Sanyo Chemical Industries, Ltd.).
], Cybinol AC-60 [trademark, Saiden Chemical
Co., Ltd.], Cybinol X-59-618 (trademark, manufactured by Saiden Chemical Co., Ltd.), and the like. The thickness of the adhesive layer is not particularly limited and can be appropriately selected within a wide range, but it is usually about 3 to 10 μm, preferably 5 to 8 μm.

As the support, a wide variety of commonly known metal plates such as steel plates, aluminum plates, iron plates, zinc plates, etc. can be used. The thickness of the support used is not particularly limited, but is usually about 0.05 to 0.3 mm, preferably 0.1 to 0.2 mm.

The lithographic printing plate for proofreading of the present invention is manufactured, for example, by the method shown below. First, add 2 pieces of aluminum foil.
By stacking the sheets and rolling them, a rough surface can be formed on the stacked surface side. The rough surface formed by rolling has an average depth of less than 0.2 μm in the case of single polymer rolling under conventional rolling conditions, but depending on the rolling force of the rolling rolls and the rolling reduction rate of the aluminum foil. A rough surface with an average depth of 1.2 μm or more can be obtained by adjusting the rolling conditions to increase the roughness. However, even if the rolling force of the rolling rolls and the rolling reduction rate of the aluminum foil are increased, it is difficult to obtain a rough surface with an average depth of more than 0.35 μm. In this case, the aluminum foils that have been polymerized and rolled once are separated, and then they are piled up again and rolled. Next, the aluminum foil having a rough surface with an average depth of 0.2 to 0.45 μm obtained above is laminated with a thermoplastic synthetic resin sheet so that the rough surface is on the outside. The aluminum foil and the resin sheet may be laminated by an extruder method using a thermoplastic resin such as polyethylene resin or ionomer resin, or by a dry lamination method using a two-component polyurethane adhesive. It's good to wear. The thickness of the bonding layer interposed between the aluminum foil and the resin sheet is usually about 3 to 8 μm, preferably 4 to 8 μm.
The thickness is preferably 6 μm. Next, an anodized film is formed on the aluminum foil side (ie, the rough surface side of the aluminum foil) of the thus obtained laminate of aluminum foil and thermoplastic synthetic resin sheet. Any conventionally known method can be used as the anodizing method. For example, using a 10-30% sulfuric acid aqueous solution as the electrolyte, the liquid temperature is about 20-40℃, and the current density is 5-40℃.
Anodizing treatment may be performed under the condition of 50 A/dm ² . After washing the laminate with the anodized film formed thereon and drying it, a photosensitizer is applied onto the anodized film. The photosensitive agent is applied by a conventionally known method, such as a gravure method, a roll coater method, a bar coater method, a flow coater method, etc. Furthermore, adhesive strength is achieved on the surface of the thermoplastic synthetic resin sheet.
50 to 250 g/25 mm of adhesive may be applied according to a known method, and this may be stuck on the support. In this way, the lithographic printing plate for proofing of the present invention is manufactured.

Examples and comparative examples are given below to further clarify the present invention.

Example 1 A 20 μm thick aluminum foil with a rough surface with an average depth of 0.35 μm was used, and a two-component type polyurethane adhesive [trademark,
Seikapond E270, manufactured by Dainichiseika Kagyo Co., Ltd.] was applied using a gravure coater to a coating amount of 5 g/m ² and laminated with a 50 μm thick polyethylene terephthalate film to obtain a two-layered laminate. Ta. After that, a 20% sulfuric acid aqueous solution was used as an electrolyte on the rough side of the aluminum foil, and the solution temperature was 30℃ and the electrolytic density was
An anodized film with a thickness of about 0.8 μm was obtained by carrying out anodization treatment under the conditions of 6 A/dm ² .
After washing with water and drying, a photodegradable photosensitive liquid containing naphthoquinone (1,2)-diazide-(2)-sulfonic acid ester and an alkali-soluble resin [trademark, Sanwaipon positive photosensitive liquid, Koyo Chemical Industry Co., Ltd. )] was applied at approximately 1.6 g/m ² . In addition, the outer surface of the polyethylene terephthalate film has adhesive strength.
150g/25mm acrylic adhesive Cybinol
-59-618 [Trademark, manufactured by Siden Chemical Co., Ltd.] 5g/
A proofing lithographic printing material in the form of a roll was prepared by applying the solution to a thickness of m ² . After that, a laminator is used to create an A1 size (690mm x 916mm) steel plate (thickness 0.2mm).
I pasted it on and cut it to the same size. A lithographic printing plate for proofing was thus obtained.

Set the positive film so that the image film surface and the photosensitive layer are in close contact with each other, and place it under vacuum in an idle fin.
2000 [Trademark, manufactured by Iwasaki Electric Co., Ltd.], 1 at light source distance of 1.3m
Exposure was done for 30 seconds. 25℃ in a specified developer (trademark, Sanwaipon positive developer, manufactured by Koyo Chemical Industry Co., Ltd.)
After immersing it in water for 30 seconds and checking for white spots on the third row of the Kodatsu Gray Scale 21 level (density 0.45), rinse with spray water, rub in the developing ink, apply the ink to the image area, and wash with water for 10 seconds.゜Be′ gum arabic solution was applied with a sponge and air dried to obtain a printing original plate.

When proof printing was performed using the Shimogaki automatic proofing machine, the ink receptivity, ink transferability, and tone reproducibility were excellent. It was found that the printing was 5 to 12% thicker from the midtones to the shadow areas.

Using the same positive film as the proof, it was printed onto a PS plate GAP for use with Fuji Photo Film Co., Ltd.'s bookbinding machine so that 5 levels of gray scale (density 0.75) were blank, and the plate was made using the usual method. When the plate was attached to the printing wheel and printing was carried out, dot thickening of 7 to 15% was observed from the middle tones to the shadow areas, and the difference in tone reproducibility between the proof printing and the actual printing was extremely narrow. The product was found to be excellent as a lithographic printing plate for proofreading.

Further, the plate after proof printing can be disposed of by peeling off the aluminum foil from the support, and the steel plate used as the support can be used repeatedly.

Example 2 A 25 μm thick aluminum foil with a rough surface with an average depth of 0.25 μm was used, and a two-component urethane adhesive [trademark, Takerakku A-975, Takeda Co., Ltd.] was applied so that the rough surface was on the outside. [manufactured by Yakuhin Co., Ltd.] was applied using a gravure coater to a coating amount of 6 g/m ² .
It was laminated with a polyester film having a thickness of 70 μm to obtain a laminate with a two-layer structure. After that, an anodized film was formed on the rough side of the aluminum foil, and then PN,N-diethylbenzenediazonium borofluoride salt [trademark, DH-200BF4, Co., Ltd.] was applied using a gravure method.
A mixture of 12 g of Daito Kagaku Kogyo Co., Ltd., 86 g of Novolac resin (trademark: Tamanol PA, Arakawa Chemical Co., Ltd.) and 52 ml of ethylene glycol monobutyl ether was applied at about 1.8 g/m ² . Next, apply 1 part of an acrylic adhesive with an adhesive strength of 100 g/25 mm to the outside of the polyester film, namely Cybinol AC-60 (trademark, manufactured by Saiden Chemical Co., Ltd.) and a polyethylene emulsion Cybinol PN-3500 (trademark, manufactured by Saiden Chemical Co., Ltd.). Co., Ltd.] was mixed and applied to a thickness of 7 g/m ² using a reverse roll coater to prepare a roll-shaped lithographic printing material for proofing. After that, A-
Cut into 2 sizes (597 mm x 700 mm), paste on an aluminum plate of the same size (0.15 mm thick), expose to light through a positive image film in the same manner as in Example 1, develop, and print. When the original plate was used as the original plate and proof printing was performed using a Shimogaki automatic proofing machine, a good printed matter similar to that of Example 1 was obtained.

Example 3 A 30 μm thick aluminum foil with a rough surface with an average depth of 0.4 μm was used, and a 4 g thick sheet was coated with a gravure coater using a two-component polyurethane adhesive so that the rough surface was on the outside. /m ² and laminated with a stretched polypropylene film having a thickness of 40 μm to obtain a two-layered laminate. After that, an anodic oxide film was formed on the rough side of the aluminum foil, and then 4,4'-diazidostilbene [trademark, manufactured by Sanpo Kagaku Kenkyujo Co., Ltd.] 10 was applied using a gravure roll method.
A mixture of 30 g of Resin M (trademark, manufactured by Maruzen Oil Co., Ltd.) and 60 g of ethylene glycol monoethyl ether was applied at 1.4 g/m ² . Next, on the outside of the stretched polypropylene film, 5 sheets of Polysic 1001-S (trademark, manufactured by Sanyo Chemical Industries, Ltd.), a self-crosslinking acrylic weak-tack removable pressure-sensitive adhesive with an adhesive strength of 110 g/25 mm, was applied to the outside of the stretched polypropylene film.
It was coated to a thickness of g/m ² to produce a proof lithographic printing material in the form of a roll. After that, A with a laminator
- pasted on two sizes of iron plates (thickness 0.2mm) and cut to the same size. A printing original plate was prepared in the same manner as in Example 1 except that it was exposed through a negative film, and a proof printing was performed using a Shimogaki automatic proofing machine. Example 1
Good prints similar to those obtained were obtained.

Example 4 A laminate similar to that used in Example 1 with an adhesive strength of 150
g/25mm acrylic adhesive Cybinol X-59
-618 [Trademark, manufactured by Siden Chemical Co., Ltd.] is applied, A1
After pasting it on a steel plate (0.2 mm thick) using a laminator, Sanwaipon negative photosensitive liquid (trademark, manufactured by Koyo Chemical Industry Co., Ltd.) was applied using a two-roll coater, and drying was performed with cold air. . After that, the negative image film was printed through in accordance with the usual method, and lacquer was applied using a Sanwaipon negative developing lacquer (trademark, manufactured by Koyo Chemical Industry Co., Ltd.).
A printing original plate was prepared by applying Sanwaipon negative finishing rubber (trademark, manufactured by Koyo Kagaku Kogyo Co., Ltd.). When the printing original plate thus obtained was run on a Shimogaki automatic proofing machine, printed matter with good ink receptivity, water retention, and reproducibility was obtained.

Example 5 The lithographic printing material obtained in Example 1 was adhered to an aluminum plate (thickness: 0.2 mm) of Heidel size (550 mm x 650 mm) using a laminator and cut into the same size. The film surface of the positive film was set so that the photosensitive layer was in close contact with the photosensitive layer, and exposure was carried out for 3 minutes under vacuum with a 2KW idle fin and a light source distance of 1.3m. Immerse in the specified developer (trademark, Sanwaipon Positive Developer, manufactured by Koyo Chemical Industry Co., Ltd.) at 25℃ for 30 seconds, check for white spots on the 5th step of the Kodatsu gray scale 21 levels (density 0.75), and then spray. After washing with water, the developing ink was rubbed in and the ink was applied to the image area, and after washing with water, a 10°Be′ gum arabic solution was applied with a sponge and air-dried to prepare a printing original plate. When the original printing plate obtained in this way was run on a Heidel KORD printing machine, it was possible to obtain printed matter with good ink receptivity, water retention, and reproducibility (comparable to offset rotary press printing), and it was not limited to proof plates. , it was found that this version can also be used satisfactorily.

The printing conditions were as follows.

Printing machine Heidel KORD Paper used Mitsubishi Tokuryo Art dampening water Koyo Resist "S/H" Ink DIC Apex black Printing speed 4000 sheets/hour Number of sheets printed 5000 sheets (can be continued but stopped for confirmation) Comparative example 1 Calibration As a printing plate, SGP-K (trademark, manufactured by Fuji Photo Film Co., Ltd.) was printed using the same positive film as in Example 1 so that the 3rd step of the gray scale was blank, and then printed using the usual method. When I made a plate using the Shimogaki automatic proofing machine and made a proof print, I could not see any thickening of the halftone dots from the midtones to the shadow areas, even though I used a blanket (JISA-74) with low surface hardness. You can also use the PS version (CAP) for this machine.
-) is exposed to light to make the halftone dots thinner as much as the halftone dots allow, and at the same time, under the printing machine conditions, a hard packing plate cylinder or a blanket with high surface hardness (JISA-77) is used. Even if you try to minimize the thickness of the halftone dots produced by this machine, as long as you use a commercially available PS plate as a proof plate, it is impossible to eliminate the difference between the proof print and the machine print without destroying the color balance. It was possible.

Comparative Example 2 According to the method described in JP-A No. 53-36302,
A composite lithographic printing sheet was produced. That is, the surface was roughened to a depth of 2μ by brush polishing and had a thickness of 150μ.
(0.006 inch) aluminum sheet with a thickness of 25
Polypropylene sheets with a thickness of 100 μm were laminated via μ (0.001 inch) fluorocarbon-treated paper (Surlyn 1652 [manufactured by DuPont] was used as the adhesive) to obtain a 275 μm laminate. Next, approximately 1.6 g/m ² of a photodegradable photosensitive liquid (Sanwaipon positive photosensitive liquid, manufactured by Koyo Kagaku Kogyo Co., Ltd.) containing naphthoquinone (1,2)-diazide-(2)-sulfonic acid ester and an alkali-soluble resin was applied using a gravure method. Then, a roll-shaped printing plate was created.

However, this printing plate had the following problems and could not be used as a lithographic printing plate for proofing.

First, the printing plate obtained above was cut into A-1 size (690 mm x 916 mm) and subjected to 4-copy printing under vacuum contact.As a result, the film edge part caused dents on the photoresist surface, and the image It was also inside.

When I tried to develop the plate using an automatic developing machine containing the specified developer (Sanwaipon positive developer, manufactured by Koyo Kagaku Kogyo Co., Ltd.), the plate wrapped around the roll and became unusable. Pour the specified developer into the vat, immerse at 25℃ for 30 seconds, check for white spots on the 3rd stage of the Kodatsu gray scale 21 steps, wash with spray water, rub the developing ink into the image area. After filling with ink and washing with water, a 10° Be′ gum arabic solution was applied with a sponge and air dried to create a printing plate, but even though it was handled very carefully, there were bulges at the edges of the plate. .

Furthermore, when I made a proof print using the Shimogaki automatic proofing machine, I found that the ink did not stick to the areas where the film edge had caused dents and edges, even though I hit the ink roller several times to improve the ink adhesion. Unfortunately, normal printing could not be performed.

Moreover, the printing plate obtained above could not be reused as a lithographic printing plate for proofing.

Claims (1)

[Scope of Claims] 1. Photosensitive layer, 2. Aluminum foil with anodized rough surface having an average depth of 0.2 to 0.45 μm, 3. Thermoplastic synthetic resin layer, 4. Adhesive strength within the range of 50 to 250 g/25 mm. 5. A lithographic printing plate for proofreading, characterized in that it is formed by sequentially laminating an adhesive layer consisting of 5. and a support consisting of a metal plate.