JPH0588378A - Method for making damping waterless lithographic printing plate - Google Patents

Abstract

PURPOSE:To obtain a damping waterless lithographic printing plate where the color blurring of a layer with the lapse of time is rare. CONSTITUTION:After a damping waterless photosensitive lithographic printing plate where a photosensitive layer and a silicone rubber layer are placed on a substrate in order is given image exposure, it is immersed in a developer containing <=4wt.% water insoluble organic solvent while rubbing it with a brush, causing the silicone rubber layer of the unexposed part to be removed. Then, it is immersed in dying liquid containing water as a main component and <=20wt.% organic solvent, causing a pattern part to be selectively dyed. This process is characteristic of the method of making a damping waterless lithographic printing plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of making a lithographic printing plate that does not require dampening water, and more particularly to a method of making a lithographic printing plate that does not require dampening water and has little deterioration in plate inspection property over time.

[0002]

2. Description of the Related Art As described in Japanese Patent Publication No. 61-53716, a conventional method for making a lithographic printing plate which does not require a fountain solution is water-soluble, which has the property of dyeing an image area exposed after development. There is known a method of rubbing the plate surface with a pad impregnated with a solution of the disperse dye, acid dye, and basic dye. By carrying out such a treatment, the end point of the development can be confirmed, and the presence or absence of scratch flaws or pinhole-like defects of the silicone rubber layer becomes obvious. Furthermore, by using a plate image area reader, it becomes possible to check the proper ink supply amount during printing.

However, Japanese Examined Patent Publication No. 61-53716
No. 2, JP-A-228258, and JP-A No. 2-34857.
No. 1,257,847, and No. 1-21483.
No. 9, JP-A 1-179047, JP-A 1-1728.
No. 34, JP-A-61-248055, etc., when the plate is actually made using the processing solution, it shows a good plate inspection property immediately after the processing, but it is not imaged after being left for several days. There is a drawback that the color bleeds in the line portion, and as a result, the color density in the halftone portion becomes darker than immediately after the processing. As described in Japanese Patent Application No. 3-105659, by using one kind of triarylmethane acid dye, color bleeding can be significantly suppressed, but it is possible to obtain by a plate-making method using such a dye. The resulting lithographic printing plate requiring no fountain solution had a drawback that the image area was slow to dry and adhered when stacked immediately after the treatment.

[0004]

When a lithographic printing plate requiring no fountain solution in which a photosensitive layer and a silicone rubber layer are sequentially laminated on a substrate, the image area after development is provided for the purpose of imparting plate inspection property. It is an object of the present invention to provide a plate making method of a lithographic printing plate that does not require a fountain solution and that, when dyed, the dye does not soak into non-image areas even after several days.

[0005]

In order to achieve the above object, the inventors of the present invention have made extensive studies, and as a result, an object of the present invention is to provide a dampening layer in which a photosensitive layer and a silicone rubber layer are sequentially provided on a support. After exposing the water-free photosensitive lithographic printing plate to image exposure, the silicone rubber layer in the non-exposed area is removed by rubbing with a brush while immersing in a developer having a water-insoluble organic solvent content of 4% by weight or less. It was found that this can be achieved by selectively dyeing the image area by removing and further immersing it in a dyeing solution containing water as a main component and an organic solvent content of 20% by weight or less. The invention has been reached.

The details of the present invention will be described below. The dyeing solution used in the plate-making method of the present invention is a dyeing solution containing water as a main component and an organic solvent content of 20% by weight or less. The dye used in the present invention is selected from basic dyes, acid dyes, disperse dyes and direct dyes. Among the water-soluble dyes, triarylmethane-based basic dyes are particularly excellent and Specific examples of the reel methane-based basic dye include the following.

[0007]

[Chemical 1]

[0008]

[Chemical 2]

[0009]

[Chemical 3]

[0010]

[Chemical 4]

These dyes can be used alone or in combination, and the content in the dyeing solution is 0.01.
A weight ratio of 10 to 10% by weight, preferably 0.05 to 4% by weight is suitable. The dyeing solution used in the plate-making method of the present invention may contain, as other additives, an organic solvent, a surfactant, an antifoaming agent or the like for the purpose of improving the dyeing concentration, leveling property, and suppressing foam. By containing an organic solvent, the diffusion of dye molecules into the organic layer to be dyed is accelerated, the dyeing concentration is increased, and it also has the effect of suppressing foaming, but the organic solvent is added to the dyed layer after plate making. If it remains, color bleeding with time is increased.

Therefore, the content of the organic solvent must be 20% or less, and more preferably 10% or less. Specific examples of such organic solvents include diethylene glycol-mono-n-pentyl ether, diethylene glycol-mono-n-hexyl ether, diethylene glycol-mono-n-heptyl ether, diethylene glycol-mono-n-octyl ether, ethylene glycol- Mono-n-pentyl ether, ethylene glycol-mono-n-hexyl ether, ethylene glycol-mono-n-heptyl ether, ethylene glycol-mono-n-octyl ether, propylene glycol-mono-n-butyl ether, propylene glycol-mono -N-pentyl ether, propylene glycol-mono-n-hexyl ether, propylene glycol-mono-n-heptyl ether, propylene glycol-mono-n-octyl Ether, dipropylene glycol-mono-n-pentyl ether, dipropylene glycol-mono-n-hexyl ether, dipropylene glycol-mono-n-octenyl ether, glycerol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, Tripropylene glycol, diethylene glycol-mono-n
-Methyl ether, 1,2-butanediol, 1,3-
Examples thereof include butanediol, 1,4-butanediol, carbitol, lactic acid, acetic acid, triethyl phosphate, methyl lactate, ethyl lactate, etc., which may be used alone or in combination with 2
Used in combination with more than one type.

In the plate-making method of the present invention, the dyeing solution is preferably heated before use. Because, as will be described later, in the plate-making method of the present invention, it is necessary to reduce the solvent remaining after the plate-making even in the developing step. This is because diffusion tends to be small. By heating the dyeing solution, the diffusion of dye molecules into the layer to be dyed is promoted, and the dyeing concentration is increased and the suppression of bubbles is achieved, as in the case where the treatment liquid contains a large amount of organic solvent. Will also contribute. Therefore, it is more preferable that the temperature of the dyeing solution is higher,
There is a risk of burns if the temperature exceeds ℃, usually 25 ℃ ~ 6
The treatment is performed at 0 ° C, preferably 30 ° C to 50 ° C.

The developing solution used in the plate-making method of the present invention preferably contains no organic solvent as much as possible. However, since the content of the organic solvent cannot be reduced to such an extent that the original developing power is lost, a water-soluble organic solvent that is less likely to remain in the layer to be dyed is preferably selected. This is because if the organic solvent is water-soluble, even if it penetrates into the layer to be dyed in the developing step, it will be washed away considerably in the subsequent dyeing step. Specific examples of such an organic solvent include glycerol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, diethylene glycol mono-methyl ether, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, diethylene glycol-mono-ethyl ether, diethylene glycol-mono-n-butyl ether, lactic acid, acetic acid, triethyl phosphate, methyl lactate, ethyl lactate, etc. may be mentioned, but these may be used alone or in combination of two or more. Used in combination. Of course, it can also be used as an aqueous solution.

Further, in order to further improve the developability, a water-insoluble organic solvent may be contained up to 4% by weight. Specific examples of such organic solvent include polypropylene glycol, diethylene glycol-mono-n-hexyl ether, lactate-n-butyl, isoamyl alcohol, n-hexanol, diethyl oxalate,
Diethyl succinate, ethylene glycol-mono-butyl ether acetate, ethylene glycol-mono-n-
Hexyl ether, phosphoric acid-tri-n-butyl, toluene, Exol D100 (manufactured by Exxon Chemical Co.) and the like can be mentioned. These are used by mixing with the above-mentioned water-soluble organic solvent, or by mixing with a suitable surfactant or the above-mentioned water-soluble organic solvent with water. The term "water-insoluble organic solvent" as used herein means that the aqueous solution does not become a transparent and uniform solution at a concentration of 4% by weight to 50% by weight at 25 ° C.

Of course, the smaller the concentration of these organic solvents is, the less color bleeding is likely to occur. Therefore, it is preferable to select the lowest concentration in the range where good developability can be maintained. You may use the developing solution which consists only. In the plate making method of the present invention, before the development step, if necessary, by dipping the photosensitive lithographic printing plate unnecessary for fountain solution after image exposure in a suitable processing liquid,
The developability can be improved. The processing solution used for this so-called pre-treatment does not use an organic solvent for the same reason as described for the developing solution, or uses a water-soluble organic solvent as exemplified for the developing solution alone or in combination of two or more kinds. Alternatively, it can be used as an aqueous solution thereof. Further, a water-insoluble organic solvent as exemplified for the developing solution can be contained within a limit of 4% by weight. These are used by mixing with the above-mentioned water-soluble organic solvent, or by mixing with a suitable surfactant or the above-mentioned water-soluble organic solvent with water.

A photosensitive planographic printing plate which does not require fountain solution used in the plate-making method of the present invention is disclosed in Japanese Examined Patent Publication No. 54-26923.
JP-B-55-22781, JP-A-63-2539
No. 49, JP-A No. 63-28025, etc., a so-called silicone rubber upper layer type fountain solution-free photosensitive lithographic printing plate can be used.

[0018]

According to the method of making a lithographic printing plate not requiring fountain solution of the present invention, the content of the water-insoluble organic solvent is 4 after image-exposing the photosensitive lithographic printing plate not requiring fountain solution. The silicone rubber layer in the non-exposed area is removed by rubbing with a brush while being immersed in a developing solution of not more than 20% by weight, and a dyeing solution containing water as a main component and an organic solvent content of not more than 20% by weight is obtained. Since the image area is selectively dyed by the immersion, the amount of the organic solvent remaining in the dyed layer of the plate after the treatment is small, and the color bleeding of the dyed layer hardly occurs over time.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0020]

【Example】

Example 1.2.3. Comparative example 1.2. Positive type no fountain solution Photosensitive lithographic printing plate TAP (Toray Industries, Inc.)
(Made by N.A. Co., Ltd.) with a positive film (50% half-tone dot image on the entire surface), and a vacuum printer FT26V manufactured by Nuark, Inc.
Exposed for 2 seconds. After exposure, remove the cover film and do not need fountain solution. Photosensitive lithographic printing plate automatic developing machine TWL860K
Water was added to the developing bath (manufactured by Toray Industries, Inc.) and the following dyeing solution was added to the dyeing bath to carry out platemaking without passing through the pretreatment bath. Further, the image area ratio of this printing plate was measured using a plate image area reader DEMIA 640 (manufactured by Dai Nippon Printing Co., Ltd.) immediately after plate making, and 3 days and 1 week later, and the dyed color density of the image area was made by Macbeth. When measured with a reflection color densitometer Macbeth RD920,
The results shown in Table 1 were obtained. (Staining liquid) Example 1. A dyeing solution having the following composition. (Liquid temperature is 35 ° C) Eisen Crystal Violet Powder ex.pure (manufactured by Hodogaya Chemical Co., Ltd.) (CI Basic Violet 3) 0.4 parts by weight Diethylene glycol-mono-ethyl ether 18 parts by weight Neugen HC (Daiichi Kogyo Seiyaku Co., Ltd.) Nonionic surfactant manufactured by Co., Ltd. 0.4 parts by weight KS-502 (silicone defoamer manufactured by Shin-Etsu Chemical Co., Ltd.) 0.002 parts by weight Water 82 parts by weight Example 2. A dyeing solution having the following composition. (Liquid temperature is 35 ° C.) Ethyl violet (CI Basic Violet 4) 0.4 parts by weight Diethylene glycol-mono-ethyl ether 7 parts by weight KS-502 0.002 parts by weight Water 93 parts by weight Example 3. A dyeing solution having the following composition. (Liquid temperature is 35 ° C) Aizen Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.) (CI Basic Violet 7) 0.4 parts by weight Diethylene glycol-mono-ethyl ether 3 parts by weight KS-502 0.002 parts by weight Water 97 parts by weight Comparative Example 1. A dyeing solution having the following composition. (Liquid temperature is 35 ° C) Eisen Basic Cyanine 6GH (Hodogaya Chemical Co., Ltd.) (CI Basic Blue 1) 0.4 parts by weight Diethylene glycol-mono-ethyl ether 30 parts by weight KS-502 0.002 parts by weight Water 70 Weight part Comparative example 2. Staining liquid having the same composition as in Example 3 (however, the liquid temperature is 20 ° C.) . Measurement result of image area ratio ───────────────────────────────── Image area ratio Image area ratio Image area ratio Staining color Concentration (immediately) (after 3 days) (after 1 week) ───────────────────────────────── Example 1 49 % 52% 55% 1.29 ───────────────────────────────── Example 2 50% 52% 54% 1.31 ───────────────────────────────── Example 3 49% 50% 52% 0.95 ── ─────────────────────────────── Comparative Example 1 50% 60% 65% 0.86 ──────── ────────────────────────── Comparative Example 2 50% 60% 66% 0.7 ───────────────────────────────── Example 4.5.6. (Comparative Example 3) (Primer layer) A 0.3 mm thick JI degreased by a conventional method.
An aluminum plate of SA1050 material was dipped in a 1% aqueous solution of KBM603 (produced by Shin-Etsu Chemical Co., Ltd.) which is an aminosilane coupling agent, and then dried at room temperature. The following primer layer was applied onto the aluminum plate so that the dry weight was 4 g / m ^2, and the film was dried and hardened by heating at 140 ° C. for 2 minutes.

Samprene IB1700D (manufactured by Sanyo Kasei Co., Ltd.) 10 parts by weight Takenate D110N (manufactured by Takeda Pharmaceutical Co., Ltd.) 0.5 parts by weight TiO ₂ 0.1 parts by weight Defender MCF323 (Dainippon Ink and Chemicals, Inc.) )) 0.03 parts by weight Propylene glycol methyl ether acetate 50 parts by weight Methyl lactate 20 parts by weight (photosensitive layer) On an aluminum plate coated with the above primer layer,
A photopolymerizable photosensitive solution having the following composition was applied so as to have a dry weight of 5 g / m ^2, and dried at 100 ° C. for 1 minute.

Samprene IB1700D (manufactured by Sanyo Kasei Co., Ltd.) 5 parts by weight A1000 (manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.5 parts by weight 1 mole of xylylenediamine / 4 moles of glycidyl methacrylate 1 part by weight Ethyl Michlers Ketone 0.35 parts by weight 2,4-diethylthioxanthone 0.1 parts by weight Victoria Pure Blue BOH naphthalene sulfonate 0.01 part by weight Defender MCF323 (manufactured by Dainippon Ink and Chemicals, Inc.) 0.03 Parts by weight Methyl ethyl ketone 10 parts by weight Propylene glycol methyl ether 25 parts by weight (Silicone rubber layer) The photopolymerizable photosensitive layer is coated with the following silicone rubber composition liquid at a dry weight of 2 g / m ² , and the temperature is 140 ° C. Dry for minutes.

Α, ω-divinylpolydimethylsiloxane (polymerization degree: about 700) 9 parts by weight (CH ₃ ) ₃ -Si-O- (Si (CH ₃ ) _2- O) _30- (SiH (CH ₃ ) -O ) ₁₀ -Si (CH ₃ ) ₃ 1.2 parts by weight Polydimethylsiloxane (polymerization degree of about 8,000) 0.5 parts by weight Olefin-chloroplatinic acid 0.2 parts by weight Reaction control agent 0.3 parts by weight Isopar G (Manufactured by Esso Kagaku Co., Ltd.) 140 parts by weight On the surface of the silicone rubber layer obtained as described above, a 12 μm-thick single-sided matt polypropylene film is placed so that the non-matted surface is in contact with the silicone rubber layer. It was laminated and dipped to obtain a waterless photosensitive lithographic printing plate.

A positive film (50% halftone dot image on the entire surface) was brought into close contact with the photosensitive lithographic printing plate not requiring fountain solution obtained in this manner, and it was applied with a vacuum printer FT26V manufactured by Nuark, USA
It was exposed for 0 seconds. After exposure, remove the cover film and do not soak water. Photosensitive lithographic printing plate automatic developing machine TWL860K
[Toray Industries, Ltd.] in a pretreatment bath of 40 ° C. diethylene glycol mono-ethyl ether 20% aqueous solution, in a developing bath 40 ° C. diethylene glycol mono-ethyl ether 20% aqueous solution, and a dyeing bath containing the following dyeing solution. I made a plate. Furthermore, this printing plate is used as a printing plate image area reader DEMI.
Using A640 (manufactured by Dainippon Printing Co., Ltd.), the image area ratio was measured immediately after plate making, and after 3 days and 1 week, and the dye color density of the image area was measured by Macbeth RD920, a reflection color densitometer manufactured by Macbeth.
The results shown in Table 2 were obtained. Example 4. A dyeing solution having the following composition. (Liquid temperature is 40 ° C.) Ethyl violet (CI Basic Violet 4) 0.4 parts by weight Diethylene glycol-mono-ethyl ether 5 parts by weight Water 95 parts by weight Example 5. A dyeing solution having the following composition. (Liquid temperature is 40 ° C.) Ethyl violet (CI Basic Violet 4) 0.4 parts by weight Water 100 parts by weight Comparative Example 3. A dyeing solution having the following composition. (Liquid temperature is 40 ° C.) Ethyl violet (CI Basic Violet 4) 0.4 parts by weight Diethylene glycol-mono-ethyl ether 30 parts by weight Water 70 parts by weight Example 6. Staining liquid having the same composition as in Example 5 (however, the liquid temperature is 20 ° C.) . Measurement result of image area ratio ───────────────────────────────── Image area ratio Image area ratio Image area ratio Staining color Concentration (immediately) (after 3 days) (after 1 week) ───────────────────────────────── Example 4 51 % 52% 55% 1.40 ───────────────────────────────── Example 5 50% 51% 53% 1.36 ───────────────────────────────── Example 6 50% 51% 53% 0.90 ── ─────────────────────────────── Comparative Example 3 49% 63% 70% 1.43 ─────── ────────────────────────── Example 7.8.9. Comparative Example 4. Example 4.5. Comparative Example 3. A positive film (50% halftone dot image on the entire surface) was brought into close contact with the photosensitive lithographic printing plate requiring no immersion water used in Example 3, and exposed for 30 seconds using a vacuum printer FT26V manufactured by Nuark, Inc., USA. After exposure, remove the cover film,
Immersion Water Not Required Photosensitive Lithographic Printing Plate Automatic Developing Machine TWL860
A pretreatment bath of K (manufactured by Toray Industries, Inc.) was charged with tap water of 40 ° C., a developing bath was also tap water of 40 ° C., and a dyeing bath was charged with the following dyeing solution to prepare a plate. Furthermore, this printing plate is used as a plate image area reader D
The image area ratio was measured using EMIA640 (manufactured by Dainippon Printing Co., Ltd.) immediately after plate making, and after 3 days and 1 week, and the dye color density of the image area was measured by Macbeth R, a reflection color densitometer.
When measured with D920, the results shown in Table 3 were obtained. Example 7. A dyeing solution having the following composition. (Liquid temperature is 40 ° C.) Ethyl violet (CI Basic Violet 4) 0.4 parts by weight Diethylene glycol-mono-ethyl ether 5 parts by weight Water 95 parts by weight Example 8. A dyeing solution having the following composition. (Liquid temperature is 40 ° C.) Ethyl violet (CI Basic Violet 4) 0.4 parts by weight Water 100 parts by weight Example 9. Dyeing liquid having the same composition as in Example 8 (however, the liquid temperature is 20 ° C.) Comparative Example 4. A dyeing solution having the following composition. (Liquid temperature is 20 ° C.) Ethyl violet (CI Basic Violet 4) 0.4 parts by weight Diethylene glycol-mono-n-butyl ether 30 parts by weight Water 70 parts by weight Table 3. Measurement result of image area ratio ───────────────────────────────── Image area ratio Image area ratio Image area ratio Staining color Concentration (immediately) (after 3 days) (1 week) ───────────────────────────────── Example 7 49% 50% 53% 1.38 ───────────────────────────────── Example 8 49% 50% 53% 1 .35 ───────────────────────────────── Example 9 50% 51% 52% 0.88 ─── ────────────────────────────── Comparative Example 4 50% 55% 65% 1.52 ───────── ─────────────────────────

Claims (2)

[Claims] 1. A water-insoluble organic solvent content of 4% by weight or less after imagewise exposure of a photosensitive lithographic printing plate that does not require fountain solution, in which a photosensitive layer and a silicone rubber layer are sequentially provided on a support. The silicone rubber layer on the non-exposed area is removed by rubbing with a brush while being immersed in the developing solution, and further immersed in a dyeing solution containing water as a main component and an organic solvent content of 20% by weight or less. A method for making a lithographic printing plate that does not require dampening water, characterized in that the image area is selectively dyed. 2. The content of the water-insoluble organic solvent in the processing solution used in the pretreatment performed prior to the developing step is 4% by weight.
The method for making a lithographic printing plate not requiring dampening water according to claim 1, wherein: