JP2530693B2 - Plate making method of waterless lithographic printing plate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a plate-making method for a waterless planographic printing plate, and particularly to a positive working waterless planographic printing using a photosensitive material containing a quinonediazite compound as a photosensitive component. The present invention relates to a plate making method.

[Prior Art] Various waterless planographic printing plates comprising a photosensitive layer and a silicone rubber layer are known. Among them, negative and positive amphoteric waterless lithographic printing is carried out by subjecting an image forming laminate comprising a photosensitive layer having a substance containing a quinonediazide structure as a constituent and a silicone rubber layer on a support in this order to a base treatment. A method for obtaining a plate is described in JP-A-59
-17552, the development latitude including image reproducibility, solvent resistance, developability, etc. of waterless planographic printing plates can be expanded, and negative and positive plates can be made from the same plate material. It has excellent features such as.

However, when a positive type waterless lithographic printing plate is obtained from the above plate material, the development latitude is narrower than in the case of obtaining a negative type waterless lithographic printing plate, and the positive working and the negative working are the same. It has the drawback that it cannot be performed using a developer.

The present inventors have made earnest studies to improve such problems, and as a result, they have found that the above problems can be satisfactorily solved by devising a plate making method, and arrived at the present invention.

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to significantly expand the development latitude even when a positive type waterless planographic printing plate is obtained, and to perform positive working and negative working in the same development. Another object of the present invention is to provide a method of making a waterless planographic printing plate that can be performed using a liquid.

[Means for Solving the Problems] An object of the present invention is to provide a waterless lithographic printing plate having a photosensitive layer and a silicone rubber layer each having a substance containing a quinonediazide structure as a constituent on a support in this order. This is accomplished by a method for making a waterless planographic printing plate characterized by performing a base treatment after exposure, then exposing the entire surface, and then developing.

The method for making a waterless lithographic printing plate of the present invention is preferably used particularly for obtaining a positive type waterless lithographic printing plate.

The waterless planographic printing plate used in the present invention is a known one having a photosensitive layer backed by a support and a silicone rubber layer provided on the photosensitive layer.

To prepare a positive type waterless lithographic printing plate from such a waterless lithographic printing plate, for example, image exposure using a positive film or a positive original image to the waterless lithographic printing plate having the above-mentioned structure,
Preferably, 5-60 mol% of the quinonediazide unit of the substance containing a quinonediazide structure in the photosensitive layer of the image-exposed area is exposed to an amount sufficient for photolysis, and then subjected to a base treatment with an amine compound or the like, The entire surface is exposed, preferably 6 to 100 mol% of the quinonediazide unit containing a quinonediazide structure in the photosensitive layer is exposed to an amount sufficient for photolysis.
Subsequently, by performing a developing treatment, a positive type waterless planographic printing plate can be obtained.

In producing a positive type waterless lithographic printing plate from such a waterless lithographic printing plate, the base treatment and whole surface exposure play important roles. That is, a portion of the substance containing a quinonediazide structure, which is image-exposed so that 5 to 60 mol% of the quinonediazide unit is photolyzed, undergoes a base treatment to improve the adhesive force with the silicone rubber layer above the base. In addition, since the solvent resistance thereof is also remarkably improved, the silicone rubber layer on the photosensitive layer is not removed even after development is performed after the entire surface is exposed in the subsequent step and the photosensitive layer and the silicone rubber layer are not removed. Both remain on the support to form a non-image area.

When the base that has not been image-exposed is subjected to a base treatment, the adhesive force with the silicone rubber layer on top of it is reduced, or the solvent resistance of the photosensitive layer is also reduced. By performing the treatment, the developability is significantly improved, and the silicone rubber layer or the silicone rubber layer and the photosensitive layer on the photosensitive layer are easily removed to form an image area.

In this way, the difference in the adhesive force and the difference in the solvent resistance between the photosensitive layer and the silicone rubber layer in the image-exposed area and the area not exposed to the image become large, so that the developability is greatly improved and the development latitude is expanded.

In the present invention, the light source used in the image exposure step and the overall exposure step is one that abundantly generates ultraviolet rays,
Mercury lamps, carbon arc lamps, xenon lamps, metal halide lamps, chemical lamps, fluorescent lamps, etc. can be used.

The support used in the present invention is not particularly limited, and those used in ordinary waterless planographic printing plates or those proposed can be used.

Examples thereof include metal plates such as aluminum, iron and zinc, and polyesters, polyolefins, transparent or opaque plastic films such as polystyrene, and composites of both. It is also possible to further coat a resin layer or the like on these sheets for the purpose of preventing halation or for other purposes to form a support.

The photosensitive layer referred to in the present invention is composed of a substance containing a known quinonediazide structure, and the substance containing a quinonediazide structure is usually used for positive PS plates, Wipon plates, photoresists and the like. It is a quinone diazide.

Examples of such quinonediazides include benzoquinone-1,2-diazide-4- or -5-sulfonic acid and polyhydroxyphenyl ester, naphthoquinone-1,
Ester of 2-diazide-4- or -5-sulfonic acid and pyrogallolacetone resin, naphthoquinone-1,2-
Mention may be made of esters of diazide-4- or -5-sulphonic acid with phenol formaldehyde novolac resins or cash-modified novolac resins. Further, a low amount of a quinonediazide compound (for example, an esterified product of naphthoquinone-1,2-diazide-5-sulfonic acid and phenol, cresol, xylenol, catechol, pyrogallol and bisphenol A) or a resin containing the above quinonediazide group A novolac resin containing no photosensitive group (for example, a soluble fusible resin obtained by condensing phenols such as phenol, cresol, xylenol, catechol and pyrogallol with formaldehyde in the presence of an acidic catalyst) You may mix.
Further, a photo-peeling photosensitive layer obtained by crosslinking quinonediazides with a polyfunctional compound as proposed in JP-A-56-80046 can be mentioned.

As the cross-linking agent, polyfunctional isocyanates, for example, paraphenylene diisocyanate, 2,4- or 2,6
-Tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate or an adduct thereof, or a polyfunctional epoxy compound, for example,
There are polyethylene glycol diglycidyl ethers, polypropylene glycol diglycidyl ethers, bisphenol A diglycidyl ether, trimethylolpropane triglycidyl ether, and the like. These heat curing is within the range that does not lose the photosensitivity of the photosensitive material, usually 130 ° C.
It is preferable to carry out the following, and therefore, a catalyst or the like is usually used together.

In addition, as a method of making a quinonediazide a monofunctional compound and modifying it to make it hardly soluble or insoluble in a developer,
Similarly, the active group of the quinonediazide compound may be esterified, amidated or urethane-modified.
The compound that reacts with the active group of the quinonediazide may be a low molecular weight compound or a relatively high molecular weight compound,
A monomer may be graft-polymerized to the quinonediazide.

Particularly preferred as the photosensitive layer used in the present invention is obtained by crosslinking or modifying a partial esterified product of naphthoquinone-1,2-diazide-5-sulfonic acid and phenol formaldehyde novolac resin with a polyfunctional or monofunctional isocyanate. It is a thing.

The thickness of the photosensitive layer is about 0.1 to 100 μm, preferably about 0.5 to 1
0 μm is suitable. If it is too thin, defects such as pinholes are likely to occur during coating, while if it is too thick, it is disadvantageous from an economical point of view.

Further, it is possible to add other components to the photosensitive layer for the purpose of improving the film-forming property and the adhesiveness with the support, within the range that does not impair the effects of the present invention.

Incidentally, the photolysis amount of the quinonediazide unit of the substance containing a quinonediazide structure in the image exposure or the whole surface exposure treatment is 2200 derived from the diazide group of the quinonediazide in the photosensitive layer in the infrared absorption spectrum (FT-IR-ATR method).
The amount of change in absorption intensity (area intensity of absorption spectrum) in the region of up to 2000 cm ⁻¹ due to exposure, that is, the amount of photolysis of diazide groups was determined based on the value of the unexposed photosensitive layer.

The photodecomposition of quinonediazide as used herein is generally referred to for quinonediazites, and is the conversion of quinonediazide to carboxylic acid upon exposure. For example, naphthoquinone-1,2-cyazide-5-sulfonic acid and phenol formaldehyde novolac resin are indenecarboxylic acids.

The silicone rubber layer used in the present invention is preferably one containing, as a main component, a linear organic polysiloxane having the following repeating units and having a molecular weight of several thousand to several hundred thousand.

Here, n is an integer of 2 or more, R and R'are an alkyl group, an alkenyl group or a phenyl group having 1 to 10 carbon atoms.
It is preferable that 60% or more of R'is a methyl group.

A crosslinking agent is usually added to this linear organic polysiloxane. As the cross-linking agent, acetoxysilane, ketoxime silane, alkoxysilane, aminosilane, amidosilane, etc. are used as a so-called room temperature (low temperature) curable silicone rubber, and a linear organic polysiloxane has a terminal hydroxyl group. In combination with these, they become deacetic acid type, deoxime type, dealcohol type, deamine type, and deamidation type silicone rubbers, respectively. A small amount of an organotin compound or the like may be added as a catalyst to these silicone rubbers.

The thickness of the silicone rubber layer is appropriately about 0.5 to 100 μ, preferably about 0.5 to 10 μ. If it is too thin, problems may occur in printing durability, while if it is too thick, it is economically disadvantageous. In addition to this, it becomes difficult to remove the silicone rubber layer during development, resulting in deterioration of image reproducibility.

In the printing plate used in the present invention, the adhesion between the support and the photosensitive layer, and the adhesion between the photosensitive layer and the silicone rubber layer are very important for basic plate performance such as image reproducibility and printing durability. Accordingly, it is possible to provide an adhesive layer between the layers or add an adhesion improving component to each layer. In particular, it is effective to provide a known silicone primer or silane coupling agent layer between the layers or add a silicone primer or silane coupling agent to the silicone rubber layer or the photosensitive layer for the adhesive force between the photosensitive layer and the silicone rubber layer. is there.

A thin protective film may be laminated on the surface of the waterless lithographic printing plate precursor configured as described above.

The waterless planographic printing plate precursor used in the present invention is produced, for example, as follows. First, using a normal coater such as a reverse roll coater, an air knife coater, a Mayer bar coater, or a spin coater such as a hoela on a support, apply a composition solution to form a photosensitive layer, dry it, and if necessary. After heat curing, if necessary, an adhesive layer is applied on the photosensitive layer by a similar method, dried and then a silicone gum solution is applied on the photosensitive layer or the adhesive layer by a similar method, usually 50 to 130 ° C. Heat treatment is carried out at a temperature of several minutes for a sufficient curing to form a silicone rubber layer. If necessary, the protective film is used by covering the silicone rubber layer with a laminator or the like.

As the base used in the base treatment after image exposure in the present invention, amine compounds (aliphatic chain amine, aliphatic cyclic amine, aromatic amine, heterocyclic amine primary,
Secondary and tertiary amines and monoamines, diamines, triamines, tetraamines, polyamines, etc.) and the like. For example, ammonia, methylamine, ethylamine, dimethylamine, diethylamine, triethylamine, trimethylamine, propylamine, butylamine, amylamine, dipropylamine, dibutylamine, diamylamine, tripropylamine, tributylamine, methyldiethylamine, ethylenediamine, trimethylenediamine, tetramethylamine. Methylenediamine, polyethyleneimine, benzylamine, N, N-dimethylbenzylamine, N, N-diethylbenzylamine, N, N-dipropylbenzylamine, o- or m- or p-methoxy or methylbenzylamine, N, N-di (methoxybenzyl) amine, β-phenylethylamine, ε, δ
-Phenylamylamine, γ-phenylpropylamine, cyclohexylamine, aniline, monomethylaniline, dimethylaniline, toluidine, benzidine, α
Or β-naphthylamine, o or m- or p-phenylenediamine, pyrrolidine, piperidine, piperazine, morpholine, urotrobin, diazabicycloundecane, pyrrole, pyridine, quinoline, hydrazine, phenylhydrazine, N, N′-diphenylhydrazine, Hydroxylamine, urea, semicarbazide, thiourea,
Tetraalkylammonium hydroxide, monoethanolamine, N-methylethanolamine, N-ethylethanolamine, Nn-butylethanolamine, diethanolamine, triethanolamine, 2- (2-aminoethyl) ethanol, 2-amino- 2-methyl-1,3
-Propanediol, 2-amino-1,3-propanediol, 2-amino-2-hydroxymethyl-1,3-propanediol, 3-hydroxypropylmethylamine,
4-hydroxybutylmethylamine, 3-methoxypropylamine, 3-ethoxypropylamine, 3-propoxypropylamine, 3-isopropoxypropylamine, 3-butoxypropylamine, 3-isobutoxypropylamine, 2-ethylhexyloxy Propylamine, 2-ethoxyethylamine, 2-propoxyethylamine, 2-butoxyethylamine, 2- (aminoethoxy) ethanol and the like are used.

These bases are used alone or as a mixture, and are used in a liquid or vapor phase. In the case of a liquid, for example, the base itself or a solution is used. When used as a solution, the solvent may be water, an organic solvent, or a mixed solution of both.

As the processing method, the plate surface may be dipped in a base processing solution, or the plate surface may be uniformly wetted with a processing solution using a brush or a pad, or the plate surface may be wet by a shower method like an automatic processor.

The treatment time is not particularly limited and can be appropriately selected depending on the strength and concentration of the base used, but usually the effect is immediately exhibited when the treatment solution is touched, and there is no change in the effect even if it is left in contact for a long time. Usually, it takes about 10 seconds to 5 minutes.

As the developing solution, those usually proposed for waterless planographic printing plates can be used. For example, water, the following polar solvent, and water to which the following polar solvent is added are suitable.

Alcohols (methanol, ethanol, etc.), ethers (ethyl cellosolve, ethyl carbitol, butyl carbitol, etc.), esters (cellosolve acetate, carbitol acetate, etc.).

[Examples] The present invention will be specifically described below with reference to Examples.

Example 1 and Comparative Example 1 An aluminum plate having a thickness of 0.3 mm (produced by Sumitomo Light Metal Co., Ltd.) was coated with the following primer composition and heat-treated at 200 ° C. for 2 minutes to form a 5 μm primer layer.

Polyurethane resin (Sampren LQ-T1331, Sanyo Kasei Co., Ltd.) 100 parts by weight Blocked isocyanate (Takenate B830, Takeda Pharmaceutical Co., Ltd.) 20 parts by weight Epoxy / phenol urea resin (SJ9372, Kansai Paint Co., Ltd.) ) 8 parts by weight Dimethylformamide 725 parts by weight Subsequently, the following photosensitive layer composition was coated on this using a bar coater and dried in hot air at 110 ° C. for 1 minute to give a thickness of 2 μm.
m photosensitive layer was provided.

Partial ester of naphthoquinone-1,2-diazide-5-sulfonic acid and phenol formaldehyde novolak resin (Sumitomo Durez: Sumirite resin PR50622) (esterification degree 25% by elemental analysis) 100 parts by weight 4,4'-diphenylmethane Diisocyanate 40 parts by weight Dibutyltin diacetate 0.2 parts by weight 4,4'-Diethylaminobenzophenone 5 parts by weight P-toluenesulfonic acid 0.8 parts by weight Tetrahydrofuran 800 parts by weight Then, a silicone rubber composition having the following composition was formed on the photosensitive layer. After spin coating, it was heat-cured at 115 ° C., dew point 30 ° C. for 3.5 minutes to form a 2.3 μm silicone rubber layer.

Polydimethylsiloxane (Molecular weight about 25,000, terminal OH
100 parts by weight Vinyltri (methylethylketoxime) silane 8 parts by weight Dibutyltin diacetate 0.1 parts by weight γ-aminopropyltrimethoxysilane 0.5 parts by weight "Isopar" E (manufactured by Exxon Chemical Co.) 1400 parts by weight As described above A 10 μm thick polypropylene film “Trefan” (manufactured by Toray Industries, Inc.)
Was laminated using a calendar roller to obtain a waterless planographic printing original plate.

The waterless lithographic printing plate thus obtained was vacuum-contacted with a positive film having a halftone dot image of 150 lines / inch, and a chemical lamp (manufactured by Toko, master printer A3)
Image exposure was carried out for 30 seconds under an illuminance of 2.5 mW / cm ² (UV meter manufactured by Oak Manufacturing Co., Ltd., using light measure type UV-402A).

This plate is then treated with “Isopar” H / butyl carbitol / ethyl cellosolve / N-methyl ethanolamine = 87.
/ 5/5/3 (weight ratio) soak in base treatment liquid. After 1 minute, only the exposed area is colored brown.

Next, the plate was taken out of the treatment liquid, and after removing the base treatment liquid with a rubber squeegee, 2.5 mW /
The entire surface was exposed for 2 minutes with an illuminance of cm ² . Then, this plate is immersed in a developer consisting of water / butyl carbitol / 2-ethylbutyric acid / crystall violet = 70/30/2 / 0.2 (weight ratio) for 1 minute and lightly rubbed with a development pad to expose the image. The silicone rubber layer of the unexposed portion is removed to expose the surface of the photosensitive layer to form an image portion, but the silicone rubber layer of the image exposed portion remains without being attacked by the developer and becomes a non-image area portion. A printing plate of an image faithful to the original film was obtained.

This printing plate is offset printing machine (Hamaduster 500CD
It was attached to A) and printing was performed using "Toyo King Ultra TKU Aquares G Eye PL" manufactured by Toyo Ink Co., Ltd., and the dot reproducibility was evaluated.
Prints with very good images with 7% reproduction were obtained.

As a comparative example, the same test was carried out on a printing plate produced without exposing the entire surface, and the dot reproducibility was 10 to 10.
It was as bad as 85%. In addition, the developability was poor, and the development time was as long as 5 minutes, so the non-image area silicone rubber layer was scratched.

Example 2, Comparative Example 2 Phenol formaldehyde novolac resin (Sumitomo Bakelite Co., Ltd .: Sumirite Resin PR5023) with a degree of esterification of 44% on a chemical conversion treated aluminum plate (Sumitomo Light Metal Co., Ltd.).
After applying a 4% by weight dioxane solution of naphthoquinone-1,2-diazide-5-sulfonate (9.7% by weight of ethanol-soluble component, the degree of esterification is determined from the IR spectrum) of 5) in dioxane for 3 minutes. To obtain a photosensitive layer having a thickness of 1.8 μm. On this photosensitive layer, 4% by weight of γ-aminopropyltriethoxysilane (UCC: A1100) based on the silicone composition was added to a 7% “Isoper” E solution of a silicone gum composition having the following composition. After uniform stirring, it was applied with a whaler. After drying, it was heated and cured at 120 ° C. and a dew point of 25 ° C. for 4 minutes to obtain a silicone rubber layer having a thickness of 2.2 μm.

Polydimethylsiloxane (Molecular weight about 80,000, OH at both ends
100 parts by weight Ethyltriacetoxysilane 5 parts by weight Dibutyltin diacetate 0.2 parts by weight 150 parts by weight of the waterless lithographic printing plate precursor obtained as described above.
A positive film having a halftone dot image of lines / inch was vacuum-contacted, and imagewise exposed to the chemical lamp used in Example 1 at an illuminance of 2.5 mw / cm ² for 60 seconds. Exposed plate in propanol /
After dipping in a base treatment solution consisting of monoethanolamine = 95/5 (weight ratio) and the image-exposed area turned brown, the base treatment solution was removed and 2.5 mW / cm 2 with the above chemical lamp
^The entire surface was exposed at an illuminance of ² for 3 minutes.

Next, soak the developer (ethanol) in the development pad,
When the plate surface is lightly rubbed, the silicone rubber layer and the photosensitive layer in the non-image-exposed areas are removed and the aluminum surface is exposed to form the image area, but the silicone rubber layer in the image-exposed area adheres firmly. It remained and became a non-image area.

This printing plate was attached to the same offset printing machine as in Example 1 and manufactured by Toyo Ink Co., Ltd. “Toyo King Ultra TKU”.
Printed using AQUALES G eye PL ", 150 lines /
Prints having good images were obtained by reproducing 5 to 95% of halftone dots.

As a comparative example, the same test was carried out on a printed matter prepared without exposing the entire surface, and the dot reproducibility was 10 to 10.
It was as bad as 80%. Moreover, the development time was as long as 7 minutes.

Reference Example This reference example shows that negative working can be performed using the same developer as that used in the positive working of Example 1.

That is, in the waterless planographic printing plate obtained in Example 1,
Using the chemical lamp used in Example 1, overall exposure was performed for 15 seconds with an illuminance of 2.5 mw / cm ² . Then, a negative film having a halftone dot image of 150 lines / inch was vacuum-contacted and exposed for 2 minutes with a chemical lamp at an illuminance of 2.5 mw / cm ² .

Subsequently, after immersing the plate in the base treatment liquid used in Example 1 for 1 minute, the plate was taken out, the base treatment liquid was removed with a rubber squeegee, and the plate was immersed in the developer used in Example 1 and lightly rubbed with a developing pad. The exposed portion of the silicone rubber layer was removed to expose the surface of the photosensitive layer. On the other hand, the portion of the silicone rubber layer that was not exposed imagewise remained firmly, and a negative working image was obtained.

This printing plate is printed in the same manner as in Example 1,
When the halftone dot reproducibility was evaluated, halftone dots of 150 lines / inch 2
~ 97% was reproduced.

[Effects of the Invention] The plate-making method according to the present invention has the advantages of good developability and wide development latitude even when applied to positive working. Further, practical effects such as positive working and negative working can be processed with the same developer can be expected.

Claims (1)

(57) [Claims] 1. A waterless lithographic printing plate comprising a support, on which a photosensitive layer having a substance containing a quinonediazide structure as a constituent and a silicone rubber layer are provided in this order.
A plate-making method for a waterless planographic printing plate, which comprises performing a base treatment, then exposing the entire surface, and then performing a developing treatment.