JPH0428295B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for developing a photosensitive lithographic printing plate, and more specifically, a method for developing a photosensitive lithographic printing plate, and more specifically, a negative-working photosensitive lithographic printing plate that can be developed with weak alkaline water and a positive-working photosensitive lithographic printing plate that can be developed with strong alkaline water. The present invention relates to a common developing method that allows planographic printing plates to be developed simultaneously using one automatic developing machine.

Conventionally, in most cases, the developer is different between negative-working photosensitive lithographic printing plates and positive-working photosensitive lithographic printing plates.
In addition, unless a positive-working photosensitive lithographic printing plate is developed with a special developer, a lithographic printing plate with sufficient performance cannot be obtained. Therefore, printers using both negative-working and positive-working photosensitive lithographic printing plates developed each plate using two automatic developers. There were complaints that installing two automatic developing machines at a small printing company would make the work space smaller and make it difficult to perform the work. Therefore, an attempt was made to simultaneously develop a special negative-working photosensitive lithographic printing plate and a special positive-working lithographic printing plate with a developer mixture of the two. However, compared to the case where the negative-working printing plate and the positive-working printing plate are developed separately using a dedicated developer, the throughput is low and is not fully satisfactory. Another attempt was to install tanks for storing a negative developer and a positive developer in one automatic processor, and when developing a negative-type photosensitive planographic printing plate, a changeover valve was used to change the negative developer solution. A proposed method is to introduce the developer into the development zone for development, collect the developer into a negative storage tank after development, and when developing a positive planographic printing plate, use a switching valve to guide the positive developer to the development zone for development. This was actually attempted, but it took a long time to change the developer, and when processing a large number of positive-working photosensitive lithographic printing plates, it became difficult to process two or three negative-working photosensitive lithographic printing plates. It has the disadvantage that it cannot be processed immediately.

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks and to provide a common developing method that can simultaneously develop a negative-working photosensitive lithographic printing plate and a positive-working photosensitive lithographic printing plate. Another object of the present invention is to provide a method by which a large number of negative planographic printing plates and positive planographic printing plates can be developed in one automatic developing machine.

As a result of extensive research, the present inventors have developed a negative-working photosensitive lithographic printing plate in which unexposed areas are eluted or swollen and developed with weakly alkaline water with a pH of less than 12.
A positive photosensitive lithographic printing plate whose exposed areas are eluted or swollen and developed by strong alkaline water with a pH of 12 or higher is used for image exposure in the first development zone, which is charged with a developer consisting of weak alkaline water with a pH of less than 12. The object of the present invention can be achieved by passing the image through a horizontal conveyance type automatic developing machine having a continuous second developing zone containing a developer consisting of strong alkaline water with a pH of 12 or higher. I found it.

The negative-working photosensitive lithographic printing plate whose unexposed areas are eluted or swollen by weakly alkaline water with a pH of less than 12 used in the present invention is made of an organic polymer having an acid value of 10 to 200 and a material that is substantially water-insoluble. A photosensitive layer comprising a photosensitive diazo compound (for example, a sulfonate or Lewis acid salt of a condensate of diphenylamine-4-diazonium salt and formaldehyde) provided on a hydrophilic support and photocurable by exposure to light. A photosensitive lithographic printing plate having the following is preferred.

Specific examples of organic polymers having an acid value of 10 to 200 include copolymers containing acrylic acid, methacrylic acid, crotonic acid, or maleic acid as essential polymerization components, such as those described in U.S. Pat. No. 4,123,276. 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, acrylonitrile or methacrylonitrile, tertiary or quaternary copolymers with acrylic acid or methacrylic acid and optionally further copolymerizable monomers, Acrylic acid or methacrylic acid, acrylic acid or methacrylic acid which has a hydroxyl group at the end and is esterified with a group containing a dicarboxylic acid ester residue, as described in JP-A-53-120903, and optionally Copolymer with other copolymerizable monomers, JP-A-54-98614
A monomer having an aromatic hydroxyl group at the end (for example, N-(4-hydroxyphenyl) methacrylamide, etc.), acrylic acid or methacrylic acid, and other co-acrylic acid as necessary. A copolymer with at least one polymerizable monomer, an alkyl acrylate or methacrylate, acrylonitrile or methacrylonitrile, and an unsaturated carboxylic acid as described in JP-A-56-4144. included. Also useful are acidic polyvinyl alcohol derivatives and acidic cellulose derivatives.

On the other hand, as the photosensitive diazo compound, diazo resins represented by a condensate of p-diazodiphenylamine and formaldehyde are useful, and diazo resins that are substantially water-insoluble and organic solvent-soluble are particularly preferred. Such preferred diazo resins are described in detail in U.S. Pat. No. 3,300,309 and JP-A-54-98613. The photosensitive diazo compound is contained in the photocurable photosensitive layer in an amount of 5 to 50% by weight, preferably 8 to 20% by weight.

A photosensitive lithographic printing plate is prepared by providing a photocurable photosensitive layer as described above on a metal support such as an aluminum plate. The surface of the aluminum plate is based on U.S. Patent No.
2714066, a chemical conversion treatment with aqueous solutions of alkali metal silicates, U.S. Pat.
After anodizing as described in No. 3181461, it is preferable to treat with an aqueous solution of an alkali metal silicate, and on the thus surface-treated aluminum plate, a photosensitive layer as described above is applied at 0.5 to 5 g/m ^{2 .} ,
It is preferably applied at a coverage of 0.8 to 3.5 g/ ^m2 ,
It is considered a photosensitive lithographic printing plate.

The developing solution made of weakly alkaline water with a pH of less than 12 used in the present invention is JP-A-51-77401;
Anionic surfactants such as those described in No. 80228, No. 53-44202 and No. 55-52054, organic solvents with solubility in water of 10% by weight or less at room temperature, alkaline agents, water and as necessary. Aqueous solutions of antifouling agents are preferred.

Examples of the anionic surfactant in the developing solution consisting of weakly alkaline water used in the present invention include sodium salt of lauryl alcohol sulfate, sodium salt of octyl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, and dibasic alkyl alcohol sulfate. Sulfuric ester salts of higher alcohols having 8 to 22 carbon atoms such as sulfate, aliphatic alcohol phosphoric ester salts such as cetyl alcohol phosphoric ester sodium salt, e.g. sodium salt of dodecylbenzenesulfonic acid, sodium salt of isopropylnaphthalenesulfonic acid , alkylaryl sulfonates such as the sodium salt of metanitrobenzenesulfonic acid, e.g. C ₁₇ H ₃₃ CON(CH ₃ )SH ₂
Sulfonic acid salts of alkylamides such as CH ₂ SO ₃ Na, sulfonic acid salts of dibasic fatty acid esters such as sodium sulfosuccinate dioctyl ester, sodium sulfosuccinate dihexyl ester, etc. are included.

Anionic surfactants are added to the developer solution during use.
It is appropriate to contain it in the range of 0.1 to 5% by weight. If it is less than 0.1% by weight, its usage effect will be low, and if it is more than 5% by weight,
For example, side effects such as excessive elution (color loss) of the dye contained in the photocurable portion of the photocurable photosensitive layer and deterioration of mechanical and chemical strength such as abrasion resistance of the photocured image may occur. comes out. Therefore, the preferred amount used is in the range of 0.5 to 1.5% by weight.

The organic solvent used in the developing solution consisting of weakly alkaline water used in the present invention has a solubility in water of about 10
Weight percent or less is suitable, preferably about 2
% by weight or less. Examples of such organic solvents include 1-phenylethanol, 2-phenylethanol, and 3-phenylpropanol.
1,4-phenylbutanol-1,4-phenylbutanol-2,2-phenylbutanol-1,
2-phenoxyethanol, 2-benzyloxyethanol, o-methoxybenzyl alcohol,
Examples include m-methoxybenzyl alcohol, p-methoxybenzyl alcohol, benzyl alcohol, cyclohexanol, 2-methylcyclohexanol, 4-methylcyclohexanol, and 3-methylcyclohexanol.

The content of the organic solvent in the developer is preferably 1 to 5% by weight. The amount used is closely related to the amount of surfactant used, and it is preferable to increase the amount of surfactant as the amount of organic solvent increases. This is because if the amount of surfactant is small and the amount of organic solvent is large, the organic solvent will not dissolve, and therefore good developability cannot be ensured by gas.

Examples of alkaline agents used in the developing solution of weakly alkaline water used in the present invention include sodium silicate, potassium silicate, potassium hydroxide, sodium hydroxide, lithium hydroxide, tertiary sodium phosphate,
Inorganic alkaline agents such as dibasic sodium phosphate, dibasic ammonium phosphate, dibasic ammonium phosphate, sodium metasilicate, sodium bicarbonate, sodium borate, ammonium borate, ammonia, etc., and monomethylamine, dimethylamine, trimethylamine, monoethylamine, Diethylamine, triethylamine, monoisopropylamine, diisopropylamine, n-butylamine,
There are organic amine compounds such as monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, ethyleneimine, ethylenediamine, polydine, etc., which can be used alone or in combination. The content of the alkaline agent in the developer is suitably 0.05 to 3% by weight, preferably 0.1 to 1% by weight. If it is less than 0.05% by weight, removal of the uncured photosensitive layer will be incomplete. On the other hand, when the amount exceeds 3% by weight, the mechanical and chemical strength of the photocured portion of the photosensitive layer deteriorates.
For example, in the case of planographic printing plates, this appears as a decrease in printing durability.

The remaining component of the developer of the present invention is water, and may further contain various additives known in the art, if necessary. For example, sodium sulfite or sodium salt of sulfopyrazolone can be added as a stain preventive agent, and ethylenediaminetetraacetic acid 4Na salt or N(-CH ₂ COONa) ₃ can be added as a water softener.

The positive photosensitive lithographic printing plate used in the present invention, in which the exposed areas are eluted or swollen and developed by strong alkaline water with a pH of 12 or higher, contains an o-quinone diazide compound and a strong alkali that is hardly soluble in weak alkaline water with a pH of less than 12. A photosensitive layer made of a water-soluble organic polymer compound is provided on the fresh water-based support,
A photosensitive lithographic printing plate having a photosensitive layer in which exposed areas are dissolved by strong alkaline water having a pH of 12 or higher upon exposure is desirable. Examples of o-quinonediazide compounds include U.S. Pat. Nos. 3046110 and 3046111.
No. 3046121 No. 3046115, No. 3046118
No. 3046119, No. 3046120, No. 3046119, No. 3046120, No.
No. 3046121, No. 3046122, No. 3046123, No. 3061430, No. 3102809, No. 3106465,
It is described in numerous publications including the specifications of the same No. 3635709 and the same No. 3647443. Among these, o-naphthoquinonediazide sulfonic acid ester or o-naphthoquinonediazidecarboxylic acid ester of an aromatic hydroxy compound, and o-naphthoquinonediazide sulfonic acid amide or o-naphthoquinonediazidecarboxylic acid amide of an aromatic amino compound are particularly preferred. , especially U.S. Pat.
3635709, a condensate of pyrogallol and acetone subjected to ester reaction with o-naphthoquinonediazide sulfonic acid, and U.S. Pat. o-Naphthoquinonediazide sulfonic acid or o-naphthoquinonediazidecarboxylic acid subjected to ester reaction, a homopolymer of p-hydroxystyrene as described in British Patent No. 1494043, or other copolymers thereof; o to the copolymer with the monomer to be obtained.
- Ester-reacted naphthoquinonediazide sulfonic acid or o-naphthoquinonediazidecarboxylic acid, copolymers of p-aminostyrene and other copolymerizable monomers as described in U.S. Pat. No. 3,759,711 A product obtained by subjecting o-naphthoquinonediazide sulfonic acid or o-naphthoquinonediazidecarboxylic acid to an amide reaction is very excellent.

Examples of organic polymer compounds soluble in strong alkaline water used in combination with these o-quinonediazide compounds include novolac type phenolic resins. Specifically, phenol formaldehyde resin, o-cresol formaldehyde resin,
Includes m-cresol formaldehyde resin and the like. Furthermore, t-
It is even more preferable to use a condensate of formaldehyde and phenol or cresol substituted with an alkyl group having 3 to 8 carbon atoms, such as butylphenol formaldehyde resin. The organic polymer compound soluble in strong alkaline water is contained in the photosensitive layer.
50 to about 85% by weight, more preferably 60 to 80% by weight.

Additives such as dyes, plasticizers, and components imparting printout performance can be added to the photosensitive layer made of an o-quinonediazide compound and an organic polymer compound soluble in strong alkaline water, if necessary.

The developer for a positive planographic printing plate whose exposed areas are eluted or swollen by strong alkaline water with a pH of 12 or higher used in the present invention is an alkali metal hydroxide, an alkali metal silicate, an alkali metal phosphate, or an alkali aluminate. A strongly alkaline aqueous solution with a pH of 12 or higher consisting of a metal salt, water, and optionally a surfactant and other additives is suitable. Specifically, Japanese Patent Application Publication No. 1973-
No. 15535, No. 53-82334, No. 54-62004, No. 52
−127338, No. 53-96307, No. 50-144502,
No. 55-22759, No. 55-25100, No. 55-95946,
No. 55-115039, No. 56-142528, No. 50-51324
Examples include developing solutions made of sodium silicate or potassium silicate as described in No.

Both the negative-working photosensitive lithographic printing plate and the positive-working photosensitive lithographic printing plate described above are passed through a horizontal conveyance type automatic developing machine having a first development zone and a second development zone in succession after image exposure. Then, the non-image areas of the photosensitive layer are removed. FIG. 1 is a schematic cross-sectional view of such an automatic developing machine, in which image-exposed negative and positive photosensitive planographic printing plates 7 are first transferred to a first development zone by a pair of insertion rollers 1 and a conveyance roller. 8 etc. to the aroma indicated by the arrow. A plurality of nozzle pipes 9 are provided above the conveyance path, and a first developer containing weak alkaline water with a pH of less than 12 stored in a tank 4 is supplied to the nozzle pipes 9 by a pump 6. The first developer is injected from the nozzle onto the surface of the photosensitive layer of the photosensitive lithographic printing plate, the surface of the photosensitive layer is further rubbed with a brush roller 3, and finally the first developer is sprayed with a pair of squeezing rollers 2. Squeezed out. The photosensitive lithographic printing plate thus passed through the first development zone is conveyed to the second development zone by a pair of insertion rollers 1'. In the second development zone as well, a plurality of nozzle pipes 9' are provided above the conveyance path of the photosensitive planographic printing plate, and a second developing solution consisting of strong alkaline water with a pH of 12 or higher is stored in the tank 5. The second developer is sent to the nozzle pipe 9' by the pump 6', and is injected from the nozzle onto the surface of the photosensitive layer of the photosensitive planographic printing plate.The surface of the photosensitive layer is further rubbed by the brush roller 3', and finally Then, the second developer is squeezed out by the squeezing roller 2'. The photosensitive lithographic printing plate 7 that has passed through the first development zone and the second development zone and has been developed is then sufficiently washed with water in a water washing zone.
In the washing zone, a pair of insertion rollers 1'' and a squeezing roller are installed, and a spray pipe 9'' is installed, and tap water stored in a tank is sent to a nozzle pipe 9'' by a pump 6'', and from the nozzle. The first developer and/or second developer adhering to the developed photosensitive lithographic printing plate is thoroughly washed away by the jetted tap water.

The first developing zone and the second developing zone of the above-mentioned horizontal conveyance type automatic developing machine may be equipped with a replenishing device suitable for each developer in order to recover from a decrease in performance due to processing of the developer. . In addition, the horizontal conveyance type automatic developing machine used in the present invention may include a continuous water washing zone after the developing zone as necessary.
It is possible to use a fixing zone, a protective gumming zone or a drying zone.

Further, the present invention will be explained in detail with reference to Examples. Note that the examples merely show examples of specific embodiments and do not limit the present invention.

Example 1 300 parts by weight of ethylene glycol monomethyl ether was heated to 100°C under a nitrogen stream, and 2-
150 parts by weight of hydroxyethyl methacrylate, 90 parts by weight of acronitrile, methyl methacrylate
A mixed solution of 79.5 parts by weight, 10.5 parts by weight of methacrylic acid, and 1.2 parts by weight of benzoyl peroxide was added dropwise over 2 hours.

15 minutes after the completion of the dropwise addition, 300 parts by weight of ethylene glycol monomethyl ether and 0.3 parts by weight of benzoyl peroxide were added, and the mixture was allowed to react for 4 hours. After the reaction was completed, the copolymer was diluted with methanol and poured into water to precipitate the copolymer, followed by vacuum drying at 70°C. The acid value of this 2-hydroxyethyl methacrylate copolymer (2) was 21.

A 2S aluminum plate with a thickness of 0.15 mm was degreased by immersing it in a 10% aqueous solution of tertiary sodium phosphate kept at 80°C for 3 minutes, and then grained with a nylon brush.
It was desmatted with a 3% aqueous solution of sodium aluminate at .degree. This aluminum plate was placed in 20% sulfuric acid.
It was anodized for 2 minutes at a current density of 2 A/dm ² and then treated with a 2.5% aqueous solution of sodium silicate at 70° C. for 1 minute.

Apply the following photosensitive liquid to this aluminum plate,
It was dried at 100° C. for 2 minutes to obtain a negative photosensitive lithographic printing plate.

2-Hydroxyethyl methacrylate copolymer () 87 parts by weight 2-methoxy-4-hydroxy-5-benzoylbenzenesulfonate of condensate of p-diazodiphenylamine and paraformaldehyde
10 parts by weight Oil Blue #603 (manufactured by Orient Chemical Industry Co., Ltd., triphenylmethane oil-soluble dye)
3 parts by weight 2-methoxyethanol 600 parts by weight Methanol 600 parts by weight Ethylene dichloride 600 parts by weight The dry coating weight was 2.5 g/m ² . A transparent negative original image was brought into close contact with this photosensitive lithographic printing plate, and the image was exposed for 40 seconds from a distance of 70 cm using a 30 ampere carbon arc lamp.

On the other hand, the U.S. patent was granted as a positive photosensitive lithographic printing plate.
Polyhydroxyphenyl naphthoquinone-1,2 obtained by polycondensation of acetone and pyrogallol as described in Example 1 of No. 3635709
- 1 part by weight of diazide-5-sulfonic acid ester and 2 parts of novolak type cresol formaldehyde resin
A photosensitive solution prepared by dissolving 0.03 parts by weight of Oil Bull #603 in 20 parts by weight of 2-methoxyethyl acetate and 20 parts by weight of methyl ethyl ketone was applied to an anodized aluminum plate after graining.
It was dried at ℃ for 2 minutes to obtain a photosensitive lithographic printing plate with a dry coating weight of 2.5 g/m ² . A transparent positive original image was brought into close contact with this photosensitive lithographic printing plate, and the image was exposed for 60 seconds from a distance of 70 cm using a 30 ampere carbon arc lamp.

In the first developing zone of a horizontal conveyance type automatic developing machine having two developing zones and then a water washing or fixing zone as shown in Fig. 1, ten times of the weakly alkaline aqueous developer shown below was charged and the developer temperature was adjusted to 30°C. It was adjusted.

Benzyl alcohol 300gr Triethanolamine 100gr Sodium isopropylnaphthalene sulfonate
100gr Sodium sulfite 20gr Trisodium nitrilotriacetate 5gr Ion exchange water 9480gr Next, add potassium silicate (SiO ₂ /
A strong alkaline aqueous developer consisting of a 5.5% aqueous solution with a K ₂ O molar ratio of 1.2 was charged 10 times and the developer temperature was adjusted to 25°C. The transport speed of this automatic processor was set so that the development time for both the first and second development zones was 20 seconds, and water was added to the second development zone so that it became a washing zone. To prevent the washing water from becoming extremely dirty, a portion of fresh water was always replenished and drained through the overflow. In addition, the strong alkaline aqueous developer in the second development zone is continuously replenished with a 12% aqueous solution of potassium silicate (SiO ₂ /K ₂ O molar ratio 1.2) during development to recover from deterioration caused by processing and carbon dioxide gas in the air. Ta.

The imagewise exposed negative photosensitive lithographic printing plates and the positive photosensitive lithographic printing plates were indiscriminately passed through the above automatic processor for processing. With this processing method, negative-working photosensitive planographic printing plates can be processed up to 4 m ² /, and positive-working photosensitive planographic printing plates can be processed up to 10 m ² / based on the developer used.
I was able to process it. When the lithographic printing plates developed in this manner were coated with a protective gum and printed, it was possible to obtain beautiful printed matter with no stains in the non-image areas of each printing plate.

Example 2 Same as Example 1 2-hydroxyethyl methacrylate/acrylonitrile/ethyl methacrylate/methacrylic acid=50/20/25/4% by weight
A 2-hydroxyethyl methacrylate copolymer () with (monomer charge ratio) was obtained. Using this 2-hydroxyethyl methacrylate copolymer (2), the following photosensitive solution was applied to the sodium silicate-treated aluminum plate of Example 1 and dried at 100°C for 2 minutes to obtain a negative photosensitive lithographic printing plate.

Diazo resin consisting of p-zoazodiphenylamine of Example 1 0.51 parts by weight 2-hydroxyethyl methacrylate copolymer () 5.00 〃 Victoria Pure Blue-BOH (Hodogaya Chemical Co., Ltd.)
) 0.10 〃 Sodium t-butylnaphthalene sulfonate
0.03 〃 Tricresidyl phosphate 0.40 〃 Phosphoric acid 0.10 〃 Fluorine surfactant (FC-430) 0.03 parts by weight Ethylene glycol monomethyl ether
50 〃 Methanol 16 〃 Methyl ethyl ketone 32 〃 Water 1 〃 The dry coating weight was 2.5 g/m ² . When this negative photosensitive lithographic printing plate was used in place of the negative photosensitive lithographic printing plate of Example 1, almost the same results as in Example 1 were obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of an automatic developing machine suitable for carrying out the developing method of the present invention. 1, 1', 1''...Insertion roller, 2, 2',
2''...Aperture roller, 3,3''...Brush roller, 4,5...Developing tank, 6,6',6''...Pump, 7...Photosensitive planographic printing plate, 8,8'... Conveyance roller, 9, 9', 9''...spray pipe,
10... Overflow outlet, 11... Tap water inlet.

Claims (1)

[Claims] 1 Negative photosensitive lithographic printing plate in which the photosensitive layer in unexposed areas is eluted or swelled and developed by weak alkaline water with a pH of less than 12, and the photosensitive layer in exposed areas is eluted or swelled in strong alkaline water with a pH of 12 or more. After image exposure, the positive photosensitive lithographic printing plate to be developed is passed through a horizontal conveyance type automatic developing machine having a first development zone and a second development zone in succession to remove the non-image area and develop it. A developing method comprising:
A common feature of negative-working and positive-working photosensitive lithographic printing plates, characterized in that the developer in the first development zone consists of weak alkaline water with a pH of less than 12, and the developer in the second development zone consists of strong alkaline water with a pH of 12 or higher. Development method.