JPH02141751A - Positive/negative type photosensitive planographic printing plate and production of planographic printing plate by using this plate - Google Patents

Abstract

PURPOSE:To obtain an improved sensitivity value even in negative type processing by forming the above printing plate of a photosensitive compsn. into which an orthoquinone diazide compd., alkali soluble resin, org. dyes, and 1 kind selected from urea, etc., are incorporated. CONSTITUTION:The photosensitive layer formed of the photosensitive compsn. contg. the orthoquinone diazide compd., the alkali soluble resin, and the org. dye, and at least one kind selected from the urea, thiourea and the deriv. thereof is formed on the base, by which the positive/negative type photosensitive planographic printing plate is formed. This planographic printing plate is subjected to image exposing then to a heat treatment and after the entire surface of the photosensitive layer is exposed, the photosensitive layer is developed by an aq. alkaline developing soln. The positive/negative type photosensitive planographic printing plate having the improved sensitivity is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [FIr: Field of Application] The present invention relates to a photosensitive lithographic printing plate that can be used for both positive and negative types, and a method for producing a lithographic printing plate using the same.

[Prior Art] In the process of producing a printing planographic plate, it is widely practiced to use two types of photosensitive planographic printing plates, positive type and negative type, in combination. However, since the materials forming the photoreceptor are different between the positive-working photosensitive lithographic printing plate and the negative-working photosensitive lithographic printing plate, different developers must be used in the development processing of the two. Therefore, when both a positive type and a negative type are used together, there is a significant reduction in work efficiency due to the replacement of the developer in the developing device and the accompanying cleaning of the equipment.

To solve the above-mentioned problems, a technique is known that allows one type of photosensitive lithographic printing plate to be used for both positive and negative types. Examples of such technology include, for example, the
A method of forming a negative image by a specific method from a photosensitive lithographic printing plate using a positive photosensitive composition containing orthoquinone diazide as disclosed in Japanese Patent No. 6-14970 is known. That is, this method normally involves image exposure using a photosensitive lithographic printing plate that can be image-wise exposed and then subjected to development to obtain a positive-tone image, followed by heat treatment, full-surface exposure, and further positive-tone development. A negative image is obtained by subsequent development with a liquid.

However, the photosensitive lithographic printing plate for both positive and negative types has a drawback of insufficient sensitivity when subjected to processing to obtain a negative type JFII image.

[Object of the Invention] An object of the present invention is to provide a photosensitive lithographic printing plate that can be used for both positive and negative types and has improved sensitivity.

Another object of the present invention is to provide a method for making a lithographic printing plate which provides improved sensitivity values in a method for making a negative-working lithographic printing plate from a photosensitive lithographic printing plate that normally exhibits positive action. .

[Structure of the Invention] The above object of the present invention is to contain an orthoquinonediazide compound, an alkali-soluble resin, and an organic dye, and to contain urea,
A photosensitive lithographic printing plate for both positive and negative working, characterized in that it has a photosensitive layer formed from a photosensitive composition containing at least one selected from thiourea and derivatives thereof on a support; This is achieved by a method for preparing a lithographic printing plate, which is characterized in that the photosensitive lithographic printing plate is subjected to imagewise exposure, then subjected to heat treatment, and then the entire surface of the photosensitive layer is exposed to light, and then developed with an aqueous alkaline developer.

The present invention will be explained in detail below.

The orthoquinonediazide compound used in the present invention is a compound having at least one orthoquinonediazide group, preferably an orthobenzoquinonediazide group or an orthonaphthoquinonediazide group, and is a compound having various known structures, such as J, 1 (written by Osar). L 1oht -
S sensitive 5ystea+sJ (J
ohnWiley & 5ons, Inc.
(published in 1965), pages 339 to 353. In particular various hydroxyl or amino compounds and 1,2-quinonediazide-
4-sulfy+>FA or 1,2-quinonediazide-5
- Esters or amides with sulfonic acid are preferred, and ester compounds of 1,2-quinonediazide-4-sulfonic acid are particularly preferred. Preferred hydroxyl compounds include condensation resins of phenols and carbonyl group-containing compounds, particularly resins obtained by condensation in the presence of an acidic catalyst. The phenols include phenol,
Examples include resorcinol, cresol, pyrogallol, etc.
Examples of the carbonyl group-containing compound include aldehydes such as formaldehyde and benzaldehyde, and ketones such as acetone.

Especially phenol/formaldehyde resin, cresol/
Formaldehyde resin, pyrogallol acetone resin,
Resorcinol benzaldehyde resin is preferred.

Typical specific examples of the orthoquinonediazide compound used in the present invention include benzoquinone-(1,2)-diazide sulfonic acid, naphthoquinone-(1,2)-diazide sulfonic acid, phenol/formaldehyde resin, or cresol/ ester with formaldehyde resin,
Naphthoquinone-(1,2)-diazide-( 2>-Synthesizer of 4-sulfonic acid and resorcinol benzaldehyde resin, naphthoquinone-(1,2)-diazide-(2)-4-
Sulfonic acid, resorcinol, pyrogallol, and acetone
Ester compounds with condensates or pyrogallol/acetone copolycondensates, and other useful orthoquinonediazide compounds include polyesters having hydroxyl groups at the terminals and orthonaphthoquinonediazide sulfones, which are described in JP-A-50-117503. ester with acid,
In particular, as described in rMII85G-113305, esters of p-hydroxystyrene homopolymers or copolymers with other styrene copolymerizable with orthonaphthoquinonediazide sulfonic acid, trihydroxy Examples include esters of benzophenone and orthoquinonediazide sulfonic acid.

In the present invention, the content m of these orthoquinone diazide compounds is preferably 5 to 60% by weight, particularly preferably 10 to 50% by weight, based on the total solid content of the photosensitive composition.

The photosensitive composition according to the present invention contains at least one of urea, thiourea, or a derivative thereof. L of urea! Examples of derivatives include methylurea, dimethylurea, ethylurea, diethylurea, propylurea, butylurea, phenylurea, diphenylurea, benzylurea,
Examples include ethyleneurea, paraphenoxyurea, α-naphthylurea, and dimethylolurea. Examples of derivatives of thiourea include methylthiourea, dimethylthiourea, ethylthiourea, diethylthiourea, propylthiourea, ethylenethiourea, phenylthiourea, diethylthiourea, 1,3-diphenylbutyl-2-thiourea, β
- Naphthyl 5rC element, etc.

Among the above compounds, preferred are urea, ethylurea, dimethylolurea, thiourea, ethylenethiourea, β-naphthylthiourea, and diethylthiourea.

In the present invention, at least one of the above-mentioned urea, thiourea or a derivative thereof is contained in the photosensitive composition in an amount of 0.2 to 10% by weight, preferably 0.5 to 4% by weight based on the total solid content. It will be done.

Further, the photosensitive composition according to the present invention needs to contain an organic dye. Preferred organic dyes include, for example, Victoria Pure Blue BOH [Hodogaya Chemical Co., Ltd.] (CI
42595), Oil Blue #603 [manufactured by Orient Chemical Industries], Patent Pure Blue [manufactured by Sumitomo Mikuni Chemical] (CI 42045), Crystal Violet (C142555), Brilliant Green (C
I 42040), ethyl violet, methyl violet (Cl 42535), methyl green (CI 45285), erythrosin B (CI
4543G), Pesic Tsuksin (CI 425
10), malachite green (Cl 42000)
, Oil Red (C160505), m-Cresol Purple, Rhodamine B (CI 45170)
, auramine (CI 4100G), 4-p-diethylaminophenylimino-naphthoquinone, triphenylmethane-based, diphenylmethane-based, oxazine-based, oxatene-based, iminonaphthoquinone-based, azomethine represented by cyano-p-dieg lyaminophenyl acetanilide, etc. and anthraquinone-based dyes.

The organic dye is preferably 0.01 to 5% by weight, more preferably 0.1 to 3% by weight based on the total solid content of the photosensitive composition.
Included within the range of

An alkali-soluble resin is used in the photosensitive planographic printing plate of the present invention. Such resins preferably contain phenolic hydroxyl groups, carboxyl groups, sulfone i! The alkali-soluble resin is preferably one obtained by condensing phenols and ketones or aldehydes in the presence of an acidic catalyst. Examples of the phenols include phenol, cresol, and p-substituted phenol. Examples of the aldehydes include acetaldehyde and formaldehyde, with formaldehyde being preferred. Acetone is preferred as the ketone.

Preferred alkali-soluble resins include, for example, phenol-formaldehyde resin, cresol-formaldehyde resin, phenol-cresol-formaldehyde copolycondensate resin as described in JP-A-55-57841, and JP-A-55-127553. Copolycondensate resins of p-substituted phenol and phenol or cresol and formaldehyde, condensates of polyhydric phenols and benzaldehyde such as resorcinol-benzaldehyde resins and Viloga 0-rubenzaldehyde resins, as described in publications. , a copolycondensate of polyhydric phenol and acetone such as pyrogallol-resorcinol-acetone resin, and xylenol-formaldehyde resin. The content m of these alkali-soluble resins is preferably 30 to 90% by weight based on the total solid content of the photosensitive composition, particularly 5% by weight.
0 to 85 weight D% is preferable.

In addition to the materials described above, the photosensitive composition used in the photosensitive lithographic printing plate of the present invention can also contain the following additives, if necessary.

That is, various low-molecular compounds (e.g. phthalates, triphenyl phosphates, maleate esters, etc.) as plasticizers, surfactants (e.g. fluorosurfactants, ethyl cell 0- nonionic activators typified by polyalkylene ethers, etc.), acid anhydrides and the like as sensitizers for positive photosensitive compositions. Additionally, compounds that generate acids or free radicals upon exposure to light and which interact with organic dyes such as those described above to change the tone of the dyes may also be included in the printout material for forming a visible image upon exposure to light. Examples of compounds that generate acids or radicals upon exposure to light include 0-naphthoquinonediazide-4-sulfonic acid halide described in JP-A No. 50-36209, and trihalomethyl described in JP-A-53-36223. -2-
Pyrone and trihalomethyl-triazine, JP-A-55-6
Orthonaphthoquinonediazide-4 described in 244@ publication
Examples include ester compounds of -sulfonic acid chloride and phenols or anilines having electron-withdrawing substituents, halomethyl-vinyl-oxazole compounds and diazonium salts described in JP-A-55-77742. These compounds vary depending on their type, but
Generally, the amount added is 0 based on the total solid content of the photosensitive composition.
．． 01-20% by weight, preferably 0.05-10iii
Amount % is appropriate.

The photosensitive lithographic printing plate of the present invention can be obtained by dissolving the photosensitive composition described above in a suitable solvent and coating the solution on a support. Examples of solvents used include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol isopropyl ether, ethylene glycol monobutyl ether, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monobutyl ether, Ethers of polyhydric alcohols such as polyester, propylene glycol 7-methyl needle acetate, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, and propylene glycol motubutyl ether are preferably used, but in addition to these, dioxane, Ethers such as tetrahydrofuran and tetrahydrobilane; Ketones such as methyl ethyl ketone, methyl abyl ketone, methyl butyl ketone, methyl amyl ketone, diethyl ketone, diacetone alcohol, cyclopentanone, and cyclohexanone: methanol, ethanol, propatool, isopropanol Alcohols such as , n-butanol, 5ec-butanol, tert-butanol, n-pentanol, isopentanol, n-hexanol, isohexanol: ethyl acetate, propyl acetate, butyl acetate, amyl acetate, hexyl acetate, propionic acid Esters such as ethyl and butyl propionate can also be used.

Examples of the support used in the photosensitive lithographic printing plate of the present invention include aluminum plates, metal plates such as zinc, copper, and iron, paper on which metals are vapor-deposited, and plastic films, but aluminum plates are most preferred. . Particularly preferred is an aluminum plate that has been subjected to surface treatments such as graining, anodizing, and, if necessary, sealing. The coating layer of the photosensitive composition on the support varies depending on the application, but the solid content in the film is 0.5 to 3.5.
A range of g/l# is suitable.

After image exposure, the photosensitive lithographic printing plate obtained as described above is developed with a positive developer to obtain a positive image. Further, a negative image can be obtained by subjecting the entire surface to a heat treatment after image exposure, further exposing the photosensitive composition again, and then developing with an aqueous alkaline developer.

Image exposure of the photosensitive lithographic printing plate in the present invention includes, for example,
The image-formed translucent film is used as an original in close contact with a photosensitive lithographic printing plate, and then exposed to a fluorescent tube, xenon lamp,
This can be carried out by various commonly used methods, such as using a publicly available light source such as a high-pressure mercury lamp charged with a metal halide or a carbon arc lamp.

Further, in the present invention, it is preferable that the heat treatment following the image a exposure is carried out at a temperature in the range of 80 to 200°C, preferably 90 to 160°C, for 1 to 30 minutes, preferably 3 to 15 minutes, If the heating temperature is too low, problems such as the photosensitive layer being dissolved in the developer during development may occur, while if the heating temperature is too high, problems such as the photosensitive composition curing may occur. be.

Such heat treatment is generally carried out by leaving the photosensitive lithographic printing plate in heated air for the above-mentioned period of time after image exposure; It is also possible to do so.

Further, the entire surface exposure performed after the heat treatment can be performed using the same apparatus as the image exposure.

Further, as the aqueous alkaline developer used for developing the photosensitive lithographic printing plate in the method of the present invention, the following developer can be mentioned. That is, the developer according to the present invention is an alkaline aqueous solution, and the alkaline agents used are preferably potassium silicate, lithium silicate, sodium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, and tertiary phosphorus. Examples include sodium acid, sodium diphosphate, potassium triphosphate, potassium diphosphate, sodium carbonate, potassium carbonate, and the like. Among these, a developer containing an alkali silicate such as potassium silicate, lithium silicate, or sodium silicate is preferable because it has good development gradation, and the composition of the alkali silicate is [Si
02 ] / [M] -〇, 5 to 1.5 (here [S
i 02 ] and [M] represent the molar turbidity of 5i02 and the molar concentration of total alkali metal, respectively. ), and Si
A developer containing 0.8 to 8% O2 is preferably used.

Of this alkali silicate composition, especially in molar ratio [Si
02 ] / [M] = 0.5 to 0.15,
A developer containing 0.8 to 4% by weight of Gatsu5i02 is preferably used because it is easy to neutralize the developer waste solution due to its low concentration, while a molar ratio of more than 0.75 and up to 1.3, Katsu5i
A developer having Q2 of 1 to 8% by weight is preferably used because it has a high buffering power and a high processing ability.

In addition, it is preferable that the alkali silicate contains 20 mol% or more of potassium as the alkali metal in the total alkali metals because it will reduce the generation of insoluble matter in the developer, and more preferably 90 mol% or more of potassium. Most preferably, the potassium content is 100 mol%.

The pH value of the developer according to the present invention is 12 or more at 25°C, preferably 12.5 to 14.0.

Furthermore, water-soluble sulfites such as sodium sulfite, potassium sulfite, lithium sulfite, and magnesium sulfite can be added to the developer. The preferred content of @salt salt in the developer is 0.05 to 4% by weight.
More preferably, it is 0.1 to 11 ω%.

Further, in the developer, anionic surfactants and amphoteric surfactants such as those described in JP-A-50-51324 and JP-A-59-75255 and JP-A-Sho 60-
By containing at least one kind of nonionic surfactants such as those described in JP-A No. 111246 and JP-A No. 60-213943, or by
By containing a polymer electrolyte as described in JP 5-95946 and JP 56-142528,
It is preferable because it can improve the wettability to the photosensitive composition and further improve the gradation. The layer to which such a surfactant is added is not particularly limited, but the concentration is preferably 0.003 to 3 ffiffi%, particularly preferably 0.006 to 1% by weight.

The developer used in the present invention can contain an antifoaming agent. Suitable antifoaming agents include precipitated silane compounds.

Various conventionally known methods can be used to develop the photosensitive lithographic printing plate of the present invention which has been imagewise exposed with the above developer. Specifically, for example, a method in which the image-exposed photosensitive lithographic printing plate is immersed in a developer, a method in which a developer is ejected from a number of nozzles onto the photosensitive layer of the photosensitive lithographic printing plate, and a developer. Examples include a method of wiping the photosensitive layer of the photosensitive lithographic printing plate with a sponge moistened with a sponge, and a method of applying a developer to the surface of the photosensitive layer of the photosensitive lithographic printing plate with a roller. Further, after applying the developer to the photosensitive layer of the photosensitive lithographic printing plate in this manner, the surface of the photosensitive layer may be lightly rubbed with a brush or the like. The developing conditions can be appropriately selected depending on the developing method. -For example,
For example, in the development method by immersion, a method is selected in which the material is immersed in a developer solution at about 10 to 40° C. for about 10 to 80 seconds.

[Examples] The present invention will be explained below using Examples, but the present invention is not limited thereto.

Example 1 A photosensitive solution having the following composition was prepared and coated on a grained aluminum plate using a roll coater to reduce the solid content to 1.
A photosensitive lithographic printing plate sample 1 was obtained by coating the sample to a coating weight of 8 Q/f and drying.

(Photosensitive liquid composition) Monotrihydroxybenzophenone and naphthoquinone (1
,2) Ester compound with -diazido-4-sulfonic acid chloride 2.3ffiffi parts・phenol,
Copolycondensation resin of m+, p-mixed cresol and formaldehyde (the molar ratio of phenol, m-cresol, and p-cresol is 48:32:20)
6.7Im part Novolac resin synthesized from paraoctylphenol and formalin 0.
9 parts by weight 2-trichloromethyl-5-(β-benzofurylvinyl)-1,3,4-oxadiazole 0.05
parts by weight - 8 parts by weight of ethylene glycol monomethyl ether, 37 parts by weight of ethylene glycol monoethyl ether, 0.07 parts by weight of Victoria Pure Blue BOH (manufactured by Hodogaya Chemical), and 0.07 parts by weight of urea. Photosensitive lithographic printing plate samples 2 to 10 were prepared in the same manner as sample 1 except that the compounds shown in Table 1 were changed.

Each of the samples 1 to 10 obtained above was cut into two pieces, one of which was exposed to a positive type original image, and then 4 pieces of sodium metasilicate were cut into two pieces.
% solution to which 0.1% sodium benzenesulfonate was added without containing an organic solvent.The image was developed by immersing it in a developer solution containing no organic solvent at a temperature of 27°C for 20 seconds to obtain a clear positive image. The obtained image is called a positive image.) For exposure, a step tablet for sensitivity measurement (No. manufactured by Eastman Kodak Co., Ltd., 2. gray scale of 21 steps with each density point of 0.15) was closely attached, and a 2KW metal halide lamp (
The test was carried out for 70 seconds at a light intensity of 8.0 mW/Cf using Iwasaki Electric (Idol Fin 2000 manufactured by ■) as a light source.

For the other sample, a negative original was exposed under the same conditions as above, left in an air constant temperature bath kept at 140°C for 5 minutes, and then the entire surface was exposed under the same conditions as the above image exposure without using the original. did. After that, 20 ml of
When immersed for a second, a clear negative image was obtained (hereinafter, the image obtained in this manner will be referred to as a negative-positive image). Table 1 shows the image forming state of the step tablet image formed on this negative-positive image.

Comparative Example 1 In Example 1, urea, Victoria Pure Blue BOH
A photosensitive lithographic printing plate sample 11 was prepared in the same manner as sample 1 using a photosensitive solution having the same composition except that both of the following were omitted, and then comparative example 1 was conducted in the same manner as in example 1. When a positive-positive image and a negative-positive image were formed on the obtained sample, the positive-positive image was stably formed, but
A negative-positive image was not stably formed, and the formed image was unclear.

Comparative Example 2 A photosensitive lithographic printing plate sample 12 was prepared in the same manner as Sample 1 using a photosensitive solution having the same composition as in Example 1 except that Victoria Pure Blue 80H was removed.
Comparative Example 2 was conducted in the same manner as above. When an image was formed on the obtained sample, stable image formation was achieved, but when compared with Samples 1 to 10, the sensitivity was inferior as shown in Table 1.

Comparative Example 3 Photosensitive lithographic printing plate sample 13 was prepared in the same manner as Sample 1 using a photosensitive liquid having the same composition as in Example 1 except that urea was omitted, and then Comparative Example 3 was prepared in the same manner as in Example 1. I did it. When an image was formed on the obtained sample, a stable image was formed, but when compared with samples 1 to 10, the sensitivity was inferior as shown in Table 1.

Comparative Example 4 In Example 1, cresol formaldehyde resin and naphthoquinone-(1,2)-diazide-5 were used instead of the ester compound of trihydroxybenzophenone and naphthoquinone-(1,2)-diazide-4-sulfonic acid chloride. - Photosensitive lithographic printing plate sample 14 prepared in the same manner as sample 1 except that an ester with sulfonic acid was used and jetanolamine was used instead of urea was treated in the same manner as in Example 1, and evaluation 111i was performed. . As shown in Table 1, results with poor sensitivity were obtained.

1, 11-” = Table 1 [Effects of the Invention] According to the present invention, a photosensitive lithographic printing plate for both positive and negative types, which can obtain improved sensitivity values even in negative processing, is provided. Ru.

Patent applicant: Konica Corporation (and one other person):

Claims (2)

[Claims] (1) A photosensitive layer formed from a photosensitive composition containing an orthoquinone diazide compound, an alkali-soluble resin, and an organic dye, and also containing at least one selected from urea, thiourea, and derivatives thereof, is placed on a support. A photosensitive lithographic printing plate for both positive and negative types, characterized by having the following characteristics: (2) A photosensitive layer formed from a photosensitive composition containing an orthoquinone diazide compound, an alkali-soluble resin, and an organic dye, and also containing at least one selected from urea, thiourea, and derivatives thereof, is placed on a support. 1. A method for producing a lithographic printing plate, which comprises subjecting a photosensitive lithographic printing plate having an image to an image, subjecting it to heat treatment, then exposing the entire surface of the photosensitive layer to light, and then developing it with an aqueous alkaline developer.