JPS63276047A - Photosensitive composition and photosensitive planographic printing plate - Google Patents

Abstract

PURPOSE:To improve plate wear by incorporating an orthoquinone diazide compd., novolak resin contg. metacresol and org. acid having a specific pKa value into a titled compsn. CONSTITUTION:This compsn. contains the orthoquinone diazide compd., the novolak resin contg. 30-90mol.%, more preferably 40-80mol.% metacresol and the org. acid having preferably 3.5-8.0pKa value. The efficiency of curing by a burning treatment is inferior and an improvement in the plate wear is not expected if the m-cresol is incorporated therein at the ratio lower than 30mol.%. The resistance to processing chemicals is low and the plate wear is again inferior if the ratio exceeds 90mol.%. Scumming arises frequently if the pKA value is <2.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a positive-working photosensitive lithographic printing plate containing an orthoquinone diazide compound as a photosensitive component and a photosensitive composition suitable for the printing plate. relates to a photosensitive lithographic printing plate with improved burning suitability and a photosensitive composition suitable for the printing plate.

(Background of the Invention) In a photosensitive composition used for a photosensitive lithographic printing plate,
Orthoquinonediazide compounds are generally known as so-called positive-type photosensitive substances that are decomposed and solubilized by active light such as ultraviolet rays. Examples of such orthoquinone diazide compounds include, for example, JP-A-47-5303;
No. 48-63802, l? No. 1148-63803,
49-38701, 56-1044, 5
6-1045, Special Publication No. 41-11222, 43-
No. 28403, No. 45-9610, No. 49-1748
1, U.S. Patent Nos. 2.797,213, 3.046.120, 3.188.210, 3,454,400, and 3,544,323 , No. 3.573,917, No. 3.674.495, No. 3.785.825, British Patent No. 1,277.60
No. 2, No. 1,251,345, No. 1,267.0
No. 05, No. 1.329.888, No. 1.330,
No. 932, German Patent No. 854,890, etc.
11! I can give you what is listed inside.

It is well known that in positive photosensitive compositions containing the above-mentioned orthoquinone diazide compound, a novolac resin with high oil sensitivity and abrasion resistance is usually used together with the compound to increase the strength of the image area.

However, in recent years, with the increase in the number of printed copies, there has been a need for printing plates with improved printing durability that can withstand printing of more than 100 pages. Merely using the lithographic printing plate used as it is was insufficient in terms of the above-mentioned stiffness resistance.

For this reason, after the photosensitive lithographic printing plate is developed, it is heated at a high temperature for a certain period of time to crosslink and harden the polymer compound in the photosensitive layer, which is a so-called burning process, to improve its abrasion resistance and solvent resistance. Attempts have been made to improve printing durability. However, when performing such a burning treatment on a photosensitive lithographic printing plate consisting of a photosensitive layer containing orthoquinonediazide and a novolak resin, the efficiency of curing the photosensitive layer is poor, and therefore, the burning treatment is more severe than usual. It is necessary to carry out the burning process under strict conditions, which is disadvantageous in terms of cost and complexity of the work.Furthermore, such a harsh process has the disadvantage that the plate surface becomes easily stained and scumming is more likely to occur. , it has been desired to improve these drawbacks.

(Objective of the Invention) An object of the present invention is to provide a photosensitive lithographic printing plate having improved burning suitability and printing durability, and a photosensitive composition suitable for the printing plate.

Furthermore, another object of the present invention is to provide a photosensitive lithographic printing plate with improved scumming caused by the above-mentioned burning process, and a photosensitive composition suitable for the printing plate.

(Structure of the Invention) The above objects of the present invention have been achieved by a photosensitive composition and a photosensitive lithographic printing plate containing the following specific components. That is, the photosensitive composition of the present invention contains (a) an orthoquinone diazide compound, and (b) metacresol.
The photosensitive lithographic printing plate of the present invention is characterized by containing a novolac resin containing 0 to 90 mol% and (c) an organic acid having a pKa value of 2 or more.
a) orthoquinone diazide compound, (b) metacresol (hereinafter referred to as m-cresol) from 30 to 90 mol%
and (c) a photosensitive composition containing an organic acid having a pKa value of 2 or more.

(Specific Structure of the Invention) Examples of the orthoquinonediazide compound in the present invention include ester compounds of 0-naphthoquinonediazide sulfonic acid and polycondensation resins of phenols and aldehydes or ketones.

Examples of the phenols include phenol, 0-
Cresol, ■-cresol, p-cresol, 3.5
- Monohydric phenols such as xylenol, carvacrol, and thymol, dihydric phenols such as catechol, resorcinol, and hydroquinone, and trihydric phenols such as pyrogallol and phloroglucin. Examples of the aldehyde include formaldehyde, benzaldehyde, acetaldehyde, crotonaldehyde, and furafural. Preferred among these are formaldehyde and benzaldehyde. Further, examples of the ketone include acetone, methyl ethyl ketone, and the like.

Specific examples of the polycondensation resin include phenol-formaldehyde resin, cresol-formaldehyde resin, at- and p-mixed cresol-formaldehyde resin, resorcinol-benzaldehyde resin, and pyrogallol-acetone resin.

The condensation rate of O-naphthoquinonediazide sulfonic acid with respect to the OH group of the phenol of the O-naphthoquinonediazide compound (reaction rate with respect to one OH group) is 15 to 80%.
is preferable, and more preferably 20 to 45%.

Further, as the orthoquinone diazide compound used in the present invention, the following compounds described in JP-A-58-43451 can also be used. That is, for example, known 1.2-quinonediazides such as 1.2-benzoquinonediazide sulfonic acid ester, 1.2-naphthoquinonediazide sulfonic acid ester, 1.2-benzoquinonediazide sulfonic acid amide, and 1.2-naphthoquinonediazide sulfonic acid amide. Compounds, specifically J. Kosar (J.
.

K osar) [Light Sensitive System]
("L 1aht-5ensistive System
ms”) pp. 339-352 (1965), John Wiley & Sons
& 5ons), New York) and W, S, D, For
est) “Photoresist” (photoresist)
1,2-benzoquinonediazide-4-sulfonic acid phenyl ester, 1°, as described in McGraw-Hill (LylcQraw-), Inc. (New 3-Li), Volume 50, (1975). 2.1'
, 2'-di(benzoquinonediazide-4-sulfonyl)-dihydroxybiphenyl, 1°2-benzoquinonediazide-4-(N-ethyl-N-β-naphthyl)-sulfonamide, 1,2-naphthoquinonediazide-5- Sulfonic acid cyclohexyl ester, 1-(1,2-naphthoquinonediazide-5-sulfonyl)-3,5-dimethyl and lazole, 1,2-naphthoquinonediazide-5-sulfonic acid-4″-hydroxydiphenyl-4″-azo −β
-naphthol ester, N,N-di(1,2-naphthoquinonediazide-5-sulfonyl)-aniline, 2'-
(1,2-naphthoquinonediazide-5-sulfonyloxy)-1-hydroxy-anthraquinone, 1,2-naphthoquinonediazide-5-sulfonic acid-2,4-dihydroxybenzophenone ester, 1,2-naphthoquinonediazide-5-sulfone It! -2,3,4-trihydroxybenzophenone ester, condensate of 2 moles of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and 1 mole of 4,4'-diaminobenzophenone, 1,2-naphthoquinonediazide-5-sulfone 2 moles of acid Olide and 4.
4'-dihydroxy-1,1'-diphenylsulfone 1
1 mole of condensate, 1 mole of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and 1 mole of purbrogalin, 1.2-naphthoquinonediazide-5-(N-dihydroabiethyl)-sulfonamide, etc. A 2-quinonediazide compound can be exemplified. Also, Tokuko Showa 3
No. 7-1953, No. 37-3627, No. 37-131
No. 09, No. 40-26126, No. 40-3801,
No. 45-5604, No. 45-27345, No. 51-
No. 13013, JP-A-48-96575, JP-A No. 48-6
1,2-quinonediazide compounds described in Publications No. 3802 and 48-63802 can also be mentioned.

As the orthoquinone diazide compound of the present invention, each of the above compounds may be used alone, or two or more thereof may be used in combination. The proportion of the orthoquinone diazide compound used in the present invention in the photosensitive composition is 5 to 60% by weight.
is preferred, particularly preferably 10 to 50% by weight.

Further, the novolak resin used in the present invention is a copolycondensate of phenols and active carbonyl compounds, and the phenols are m-cresol with a ratio of 30% to 30% relative to the novolak resin.
It is necessary to contain 90 mol%, preferably 40 to 80 mol%.

That is, if the cresol content is less than 30 mol%, the curing efficiency by the above-mentioned burning process will be poor and no improvement in printing durability can be expected, and if it exceeds 90 mol%, the resistance to processing chemicals will be poor. If the printing quality is poor, the printing durability will be poor, which is not preferable.

In addition, the phenols which are copolycondensation components with the above-mentioned --cresol include all compounds in which at least one hydrogen atom bonded to an aromatic ring is substituted with a hydroxyl group, and specifically, for example, phenol , O-cresol,
p-cresol, 3゜5-xylenol, 2.4-xylenol, 2゜5-xylenol, carvacrol, thymol, catechol, resorcinol, hydroquinone, pyrogallol, phloroglucin, or alkyl group (1 to 8 carbon atoms) substituted phenol etc., preferably phenol, 0-cresol, or p-cresol.

The active carbonyl compounds include, for example, aldehydes and ketones, and specific examples include formaldehyde, acetaldehyde, benzaldehyde, acrolein, furfural, and acetone.

Specific examples of the novolac resin used in the present invention include phenol/m-cresol/formaldehyde copolycondensate resin, 0-cresol/m-cresol/formaldehyde copolycondensate resin, m-cresol/p-
Preferable examples include cresol/formaldehyde copolycondensate resin, 0-cresol/l-cresol/p-cresol/formaldehyde copolycondensate resin, and phenol/m-cresol/p-cresol/formaldehyde copolycondensate resin.

The most preferred novolak resin in the present invention is an I-cresol/p-cresol/formaldehyde copolycondensate resin consisting of m-cresol, p-cresol, and formaldehyde, or a phenol/l-cresol/p-cresol copolycondensate resin.
- A phenol/m-talesol/p-cresol/formaldehyde copolycondensation resin consisting of cresol and formaldehyde.

These novolak resins mentioned above may be used alone or in combination of two or more.

The molecular weight of the novolac resin (polystyrene standard) is
Preferably the number average molecular weight (Mo) is 3, OQ
Q2 ~7.50 x 103, weight average molecular weight (
M guest) is 1.0 (l x 103~3.00 x 10
4, more preferably Mo is 5.00 x 1Q2~a,
oo xl 03, M'# is 3.00 x 103
~2.00 x 10''.

The molecular weight of such novolac resins can be measured using GPC (
It is carried out by gel permeation chromatography method). Number average molecule ffiMn and weight average molecule ff1M
Calculation of * is done by smoothing the peaks of the oligomer region (the centers of the peaks and valleys are This method shall be used.

In addition, as a method for confirming the composition of the phenols used in the synthesis of the novolak resin, pyrolysis gas chromatography (Pyrolysis-+;
+aschroaatoraphy, PGC) is used. Regarding pyrolysis gas chromatography, its principles, equipment, and experimental conditions are described in, for example, the Journal of the Chemical Society of Japan,
New book by Tsuge “New Experimental Chemistry Course” Volume 19 Polymer Chemistry [I
] pages 474 to 485 (published by Maruzen 1978), etc., and the qualitative analysis method of novolak resin by pyrolysis gas chromatography is described in Morio Tsuge, Takashi Tanaka, Masayuki Tanaka, "Analytical Chemistry" Vol. 18, 47. The method described on pages 52 to 52 (1969) is followed.

The content of these novolak resins in the photosensitive composition is preferably 30 to 95% by weight, more preferably 50 to 90% by weight.

The tlAM in the present invention needs to have a pKa value of 2 or more, but preferably has a pKaii of 3.0 to 9.
．． 0, more preferably 35 to 8.0. pK
When the a value is less than 2, the above-mentioned scumming occurs significantly, which is not preferable for the purpose of the present invention.

However, 1) Kalii used in the present invention is a value at 25°C. Examples of such organic acids include Chemical Handbook Group 1! Edited by ■ (Maruzen ■ 1966, No. 1054-105
I) Kala of the present invention is an organic acid described on page 8.
Compounds that can exhibit the following can be mentioned. Examples of such compounds include adipic acid, azelaic acid, isophthalic acid, β-ethylglutaric acid, m-oxybenzoic acid, p-oxybenzoic acid, glyceric acid, glutaconic acid,
glutaric acid, succinic acid, β, β-diethylglutaric acid,
1,1-cyclobutanedicarboxylic acid, 1,3-cyclobutanedicarboxylic acid, 1,1-cyclopentanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, β,β-dimethylglutaric acid , dimethylmalonic acid, d-tartaric acid, sperinic acid, terephthalic acid, pimelic acid, phthalic acid, fumaric acid, β-propylglutaric acid, propylmalonic acid, mandelic acid, mesotartaric acid, β-methylglutaric acid, β, β- Methylpropylglutaric acid, methylmalonic acid, malic acid, 1.1-hexanedicarboxylic acid? ! Examples include 1.1.2-cyclohexanedicarboxylic acid, 1.3-cyclohexanedicarboxylic acid, and 1.4-cyclohexanedicarboxylic acid. Other organic acids having an enol structure such as Meldrum's acid and ascorbic acid can also be preferably used.

The proportion of the organic acid in the photosensitive composition is from 0.05 to
10% by weight is suitable, preferably 0.1-5% by weight
It is.

The photosensitive composition of the present invention can achieve the object of the present invention by the combination of the orthoquinone diazide compound, novolak resin, and I1M, but in addition to these materials, if necessary, a dye may be added. , dyes such as pigments, plasticizers, etc. can be added.

Furthermore, a lipophilic resin may be added to the photosensitive composition of the present invention in order to improve the oil sensitivity of the photosensitive composition. The photosensitive lithographic printing plate of the present invention can be formed by dissolving each of these components in the following solvents and coating and drying the solution on the surface of a suitable support to provide a photosensitive layer.

Solvents that can be used to dissolve each component of the photosensitive composition of the present invention include cellosolves such as methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, and ethyl cellosolve acetate, dimethyl formamide, dimethyl sulfoxide, dioxane, acetone, Examples include cyclohexanone, trichloroethylene, and methyl ethyl ketone. These solvents may be used alone or in combination of two or more.

The coating method used when applying the photosensitive composition of the present invention to the surface of the support includes conventionally known methods, such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, and curtain coating. Coating etc. are possible. At this time, the coating m varies depending on the application, but for example, the solid content is preferably 0.5 to 5.0 (J/f).

The support on which the photosensitive layer using the photosensitive composition of the present invention is provided can be a metal plate made of aluminum, zinc, steel, copper, etc., or a plated or vapor-deposited plate of chromium, zinc, copper, nickel, aluminum, iron, etc. Examples include metal plates, paper, plastic films, glass plates, paper coated with resin, paper covered with metal foil such as aluminum, and plastic films treated to make them hydrophilic. Preferred is an aluminum plate. As the support for the photosensitive lithographic printing plate of the present invention, it is more preferable to use an aluminum plate that has been subjected to surface treatments such as graining, anodizing, and, if necessary, sealing.

Known methods can be applied to these treatments.

In general, a photosensitive lithographic printing plate is exposed and baked using a device and then developed with a developer, leaving only the unexposed portions on the surface of the support to form a positive-positive relief image.

As the developer used for developing the photosensitive lithographic printing plate of the present invention, an aqueous alkaline developer is suitable. Examples of the aqueous alkaline developer include aqueous solutions of alkali metal salts such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium metasilicate, potassium metasilicate, sodium diphosphate, and sodium triphosphate. can be mentioned.

In the photosensitive lithographic printing plate of the present invention, a burning process is performed after the above development process, and such a burning process is performed by heating with a burning oven or gas fire, or by placing it in a heated liquid, etc. The heating temperature and time can be appropriately selected depending on the photosensitive composition to be used, but in particular, the heating temperature is 140 to 140℃.
The temperature is preferably in the range of 250°C, for example, when the temperature is 150°C, the heating time is preferably in the range of 6 to 20 minutes.
For example, when the temperature is 240°C, the heating time is preferably within the range of 3 to 10 minutes.

Examples of the photosensitive composition and photosensitive lithographic printing plate of the present invention will be described in detail below, but the present invention is not limited to these Examples in any way.

(Example) Aluminum plate with a thickness of 0.24I1m (material: 1050,
After degreasing H16) in a 5% by weight aqueous sodium hydroxide solution at 60°C for 1 minute, it was degreased in a 0.5 molar hydrochloric acid aqueous solution of 12 at a temperature of 25°C and a current density of 60A.
Electrolytic etching treatment was performed under the conditions of /df, treatment time: 30 seconds. Next, after desmutting in a 5% by weight aqueous sodium hydroxide solution at 60°C for 10 seconds,
Temperature: 20°C, current density: 3A/in 0% by weight sulfuric acid solution
df.

Treatment time: Anodization treatment was performed under conditions of 1 minute.

Furthermore, hot water sealing treatment was performed with hot water at 30°C for 20 seconds.
An aluminum plate as a support for lithographic printing plate material was produced.

Example 1 A photosensitive composition coating solution having the following composition was applied to the aluminum plate prepared as above using a rotary coater, and dried at 90°C for 4 minutes to obtain a positive-working photosensitive lithographic printing plate sample. .

(Composition of photosensitive composition coating solution) Copolycondensation resin of m-cresol, p-cresol, and formaldehyde (molar ratio of m-cresol and p-cresol each is 7:3, MW = 9.000.M
v/Mn = 6.0) 6.0 g・
Esterified product of 1,2-naphthoquinone-2-diazido-5-sulfonyl chloride and pyrogallol-acetone resin 2.0(]・Succinic acid 0.24g・Victoria Pure Blue BOH (manufactured by Hodogaya Chemical ■) 0.07g
・2-Trichloromethyl-5-[β-(2-benzofuryl) and nil] 1゜3.4-oxadiazole 0.13jJ ・Methyl cellosolve 100112 On the thus obtained photosensitive lithographic printing plate material, a sample for sensitivity measurement was applied. Step tablet (Eastman Kodak N002
, 21 levels of gray scale with a density difference of 0.15) in close contact with each other, and a 2KW metal halide lamp (Idol Fin 2000 manufactured by Taiwa Electric Co., Ltd.) was used as the light source to generate 8.0 mW.
/Cf conditions.

Next, this sample was developed with a developer prepared by diluting 5DR-1 (Konishi Roku Photo Industry H) 8 times with water at 25°C until the 5th stage of the step tablet was clear, and a lithographic printing plate was obtained. Ta.

Next, this lithographic printing plate was pretreated with BC-3 (manufactured by Fuji Photo Film Co., Ltd.), and then heated at 150°C using an ordinary electric furnace.
A burning process was performed for a minute.

A printing test was conducted using the lithographic printing plate thus obtained. Printing is done using DIC Dai-Cure Process Red Ink (Dainippon Ink & Chemicals), and Ultra Plate Cleaner (Ultra Plate Cleaner, which is used to clean the printing plates every time 5000 sheets are printed).
A, B, C (manufactured by Chemical Co., Ltd.) were used to wipe the plate surface while inserting the paper.

Table 1 shows the results of such tests, and the evaluation of scumming and printing durability.

Examples 2 to 6 The copolycondensation resin of l-cresol, p-cresol, and formaldehyde, which are novolac resins, and/or succinic acid, which is an organic acid, in the photosensitive composition coating solution composition of Example 1 are shown in Table 1. A photosensitive lithographic printing plate was prepared in the same manner as in Example 1 except for the changes as shown, and Examples 2 to 6 were conducted, respectively, and evaluations were performed in the same manner as in Example 1.

The results are shown in Table 1.

Comparative Examples 1 to 6 Table 1 shows the copolycondensation resin of m-cresol, p-cresol, and formaldehyde, which are novolak resins, and/or succinic acid, which is R acid, in the photosensitive composition coating solution composition of Example 1. Example 1 except with changes as shown
Comparative photosensitive lithographic printing plates were prepared in the same manner as in Comparative Examples 1 to 6, respectively. The results are shown in Table 1.

This IA: Copolycondensation resin of m-cresol, p-cresol, and formaldehyde (molar ratio of n+-cresol and p-cresol each is 7:3, MW = 9,000
, Mw /Mn -6,0) Ba11-cresol and p
- Copolycondensation resin of cresol and formaldehyde (l
- molar ratio of cresol and p-cresol is 5=5, M
W = 6,000, MW /Mn = 5.0)C:
A copolycondensation resin of phenol, m-cresol, p-cresol, and formaldehyde (the molar ratio of each of phenol, m-cresol, and p-cresol is 3.0:
4.2:2.8, MW = 10,000, Mw /Mn
= 6.7) Copolycondensation resin of all-cresol and formaldehyde (MW = 2,000, MW /Mn
=2.5) b: Copolycondensation resin I of phenol, 1-resol, p-cresol, and formaldehyde.

(The molar ratio of phenol, -1-cresol and p-cresol is 4:2:4, MW = 9,000,
MW /Mn = 5.2) *2 0: No background smudge △: Slight background smudge Even after printing a total of 30,000 sheets, clear printed matter could be obtained and no background stains were observed.

The lithographic printing plates used in Comparative Examples 2.3.5 and 6 were 15,0
When printing on 00 sheets, io, and ooo sheets, some of the halftone dots in the shadows became tangled, and furthermore, scumming occurred in the fringe portion of the erased area. Furthermore, after washing during printing, the ink receptivity in the image area deteriorated, making it impossible to obtain clear printed matter.

Furthermore, in Comparative Examples 1 and 4, printing of 30,000 sheets or more was possible, but background smear similarly occurred.

(Effects of the Invention) As explained in detail above, the present invention improves burning suitability, resulting in excellent printing durability and a photosensitive lithographic printing plate containing an orthoquinone diazide compound that does not cause scumming, and the printing plate. We were able to obtain a photosensitive composition suitable for.

Claims (2)

[Claims] (1) A photosensitive composition comprising (a) an orthoquinone diazide compound, (b) a novolak resin containing 30 to 90 mol% of metacresol, and (c) an organic acid having a pKa value of 2 or more. (2) on the support (a) orthoquinonediazide compound,
Photosensitivity characterized by having a photosensitive layer formed from a photosensitive composition containing (b) a novolak resin containing 30 to 90 mol% of metacresol and (c) an organic acid having a pKa value of 2 or more. Lithographic printing plate.