JPH09244262A - Aqueous developer for photosensitive printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aq. developer for developing a photosensitive original plate preventing the aggregation of scum after development, having high development speed independently of the quality of the water and ensuring slight unevennes in image reproducibility. SOLUTION: The rear side of a photosensitive original plate contg. a hydrophilic polymer such as a styrene-butadiene copolymer having phosphoric ester groups is exposed using a UV exposure system so that the thickness of a cured layer is regulated to about 1.5mm. A negative film is brought into contact with the unexposed surface and this surface is exposed using the UV exposure system for 15min. The negative film is peeled and the unexposed part is removed with an aq. soln. contg. 2% polyoxyethylene nonyl phenyl ether and 0.1% tetrasodium ethylenediaminetetraacetate in tap water. Tap water is then jetted on the original plate through a jet nozzle, the original plate is dried by blowing air with a fan and the surface removed the unexposed part is re-exposed using the UV exposure system for 10min to form a relief image.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an aqueous developer for a photosensitive printing plate. More specifically, it relates to an aqueous developer for removing a non-exposed portion of a photosensitive printing original plate to form a relief.

[0002]

2. Description of the Related Art A photosensitive printing plate can be obtained by laminating a printing film on a printing original plate, irradiating it with actinic light, and then dissolving or scraping the unexposed portion to form a relief. In the development for removing the unexposed portion, a developing solution in which a surfactant, an alkali metal salt and the like are dissolved is used. However, when developed with an aqueous developer such as an aqueous solution of a surfactant, the development debris removed from the unexposed portion aggregates and adheres to the brush of the brush to reduce the development speed. Further, development debris adheres to the surface of the photosensitive printing plate, and image reproducibility deteriorates. In addition, the development rate may change significantly depending on the water quality of the water in which the surfactant or the like is dissolved, and the image reproducibility may vary.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides an aqueous developer for developing a photosensitive printing original plate, which prevents the aggregation of development debris, has a high development rate regardless of the water quality, and has little variation in image reproducibility. That is the purpose. The inventors of the present invention have conducted extensive studies in order to achieve the above-mentioned object, and as a result, the development rate is extremely reduced in an aqueous developer using water of water quality containing heavy metals as a solvent, and a chelating agent and an interface. By using an aqueous solution with an activator as a developing solution, it was found that the developing speed can be increased and the aggregation of development debris can be prevented, and the present invention has been completed based on this finding.

[0004]

According to the present invention, there is thus provided (1) an aqueous developer for developing a photosensitive printing plate comprising an aqueous solution containing a chelating agent and a surfactant. .

The following are provided as preferred embodiments of the aqueous developer of the present invention. (2) The aqueous developer according to (1) above, wherein the chelating agent is water-soluble. (3) The aqueous developer according to (1) above, wherein the chelating agent is polyaminocarboxylic acid and an alkali metal salt or ammonium salt thereof.

(4) The aqueous developer according to (1) above, wherein the surfactant is an anionic or nonionic surfactant. (5) The aqueous developer according to (1) above, wherein the surfactant is a fatty acid alkanolamide.

Further, according to the present invention, (6) a step of bringing the printing film into close contact with the photosensitive printing original plate, irradiating active light from the printing film side, peeling the printing film, and carrying out the above (1)
To (5) a method for producing a photosensitive printing plate, comprising: a step of developing with an aqueous developing solution to remove an unexposed portion; and a step of irradiating a developed photosensitive printing original plate with active light. .

The following are provided as preferred embodiments of the production method of the present invention. (7) A composition in which the photosensitive printing original plate contains a hydrophilic polymer, a photopolymerizable ethylenic monomer, and a photopolymerization initiator,
The method according to (6) above, which preferably comprises a composition further containing an elastomer. (8) The method according to (7) above, wherein the hydrophilic polymer has a phosphate ester group or a carboxylic acid group pendantly bonded to each other.

(9) The production method of (7) above, wherein the elastomer is a thermoplastic elastomer such as a styrene-butadiene block copolymer or a styrene-isoprene block copolymer.

(10) The method according to the above (6), characterized in that the developed photosensitive printing original plate is rinsed with an aqueous rinse solution before the step of irradiating the developed photosensitive printing plate with active light. (11) The method according to (10) above, wherein the aqueous rinse liquid is an aqueous solution containing a chelating agent.

(12) After the step of rinsing the developed photosensitive printing original plate with an aqueous rinse solution, a step of blowing air to the rinsed photosensitive printing original plate is carried out, and thereafter, the photosensitive printing original plate blown with air is exposed to active light. The process of (6) above, which comprises performing the step of irradiating with.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The aqueous developer of the present invention comprises an aqueous solution containing a surfactant and a chelating agent.

The surfactant is a substance which dissolves in water to lower the surface tension of water. Specifically, sodium laurate, sodium myristate, sodium palmitate, sodium stearate, sodium oleate, potassium laurate, potassium myristate,
Potassium palmitate, potassium stearate, potassium oleate, N-acyl-N-methylglycine salt, N
-Acyl-N-methyl-β-alanine salt, N-acylglutamate, polyoxyethylene alkyl ether carboxylate, carboxylate such as acylated peptide; alkylbenzenesulfonate, alkylnaphthalenesulfonate, naphthalenesulfonate Salt, formalin condensate of melamine sulfonate, dialkyl sulfosuccinate ester salt, alkyl sulfoacetate salt, α-olefin sulfonate, sulfonate such as N-acylmethyl taurine; sulfated oil, higher alcohol sulfate ester salt, Sulfuric acid such as secondary higher alcohol sulfate ester salt, alkyl ether sulfate salt, secondary higher alcohol ethoxy sulfate, polyoxyethylene alkylphenyl ether sulfate salt, monoglycer sulfate, and sulfate ester salt of fatty acid alkylolamide. Acid ester salts; anionic surfactants such as phosphoric acid ester salts such as alkyl ether phosphoric acid ester salts and alkyl phosphoric acid ester salts; aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride , Pyridinium salts, Imidazolinium salts and other cationic surfactants; Carboxybetaine, aminocarboxylic acid salts, imidazolinium betaines, lecithins and other amphoteric surfactants; Polyoxyethylene alkyl ethers, single chain length polyoxyethylene Alkyl ether, polyoxyethylene secondary alcohol ether, polyoxyethylene alkylphenyl ether, polyoxyethylene sterol ether, polyoxyethylene lanolin derivative, ethylene oxide derivative of alkylphenol formalin condensate, Ethers such as oxyethylene polyoxypropylene block polymer and polyoxyethylene polyoxypropylene alkyl ether; ether esters such as polyoxyethylene glycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester and polyoxyethylene sulbitol fatty acid ester; polyethylene glycol Esters such as fatty acid ester, fatty acid monoglyceride, polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, sucrose fatty acid ester; fatty acid alkanolamide, polyoxyethylene fatty acid amide, polyoxyethylene alkylamine,
Nonionic surfactants such as nitrogen-containing compounds such as alkylamine oxides; fluorinated surfactants such as fluoroalkylcarboxylic acids, disodium N-perfluorooctanesulfonylglutamate, and perfluorooctanesulfonic acid diethanolamide; Examples thereof include sulfuric acid ester salts of oxyethylene allyl glycidyl nonyl phenyl ether and reactive surfactants such as polyoxyethylene allyl glycidyl nonyl phenyl ether. Among these surfactants, anionic surfactants or nonionic surfactants are preferably used. The amount of surfactant is usually 0.0 in aqueous solution concentration.
It is 1 to 5% by weight, preferably 0.1 to 2% by weight.

The chelating agent is a compound having a polydentate ligand which forms a chelate compound by binding with a metal ion, and has an acid group (carboxylic acid group, sulfonic acid group, hydroxyl group, etc.) having a salt-forming ability or It has an atomic group (amines, carbonyl group, etc.) having a coordinating ability in its molecular structure. Specifically, polyaminocarboxylic acids such as ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, nitrosotriacetic acid, hydroxyethyliminodiacetic acid, hydroxyethylenediaminetriacetic acid and triethylenetriaminehexaacetic acid, and alkali metal salts or ammonium salts thereof; citric acid , Malic acid, tartaric acid, glycolic acid, salicylic acid, mandelic acid, lactic acid, 2-hydroxybutyric acid, 2-
Hydroxycarboxylic acids such as hydroxy-2-methylpropanoic acid, leucic acid, dietosalic acid, hydroacrylic acid, ricinoleic acid, glyceric acid, tartronic acid, acetoxysuccinic acid, citramalic acid, grape acid and desoxalic acid, and alkali metal salts thereof. Or an ammonium salt; an oxocarboxylic acid such as glyoxylic acid, malonaldehyde acid, succinaldehyde acid, pyruvic acid, 2-oxobutyric acid, acetoacetic acid, repurinic acid, and mesooxalic acid, and an alkali metal salt or ammonium salt thereof;
Examples thereof include dimethyl oxime, oxine, dithizone and acetylacetone. Although an oil-soluble chelating agent can be used, a polyaminocarboxylic acid which is easily soluble in water and its alkali metal salt or ammonium salt are preferably used. The amount of the chelating agent is usually 0.01 to 10% by weight in the aqueous solution concentration, preferably 0.05 to
5% by weight, based on 100 parts by weight of the surfactant,
Usually, it is 2 to 200 parts by weight.

In the developer of the present invention, in addition to the above-mentioned surfactant and chelating agent, an alkali metal hydroxide,
Basic compounds such as carbonates; acidic compounds such as mineral acids and organic acids that do not form chelate compounds can be added.

The photosensitive printing original plate to which the developing solution of the present invention can be applied is not particularly limited, but those in which the unexposed portion is dissolved or swelled by water (water-developable) are preferable. The water-developable photosensitive printing original plate is usually composed of a composition containing a hydrophilic polymer, a photopolymerizable ethylenic monomer and a photopolymerization initiator, and preferably a composition further containing an elastomer. Is.

As the elastomer, a thermoplastic elastomer such as a styrene-butadiene block copolymer or a styrene-isoprene block copolymer is preferably used. By blending the elastomer, the mechanical strength balance and water developability of the printing plate are improved.

The hydrophilic polymer has a side chain of its molecule,
-OH, -COO -, - COOH, -NH 2, -SO
_{3 -, - SO 3 H,} -PO (OH) 2, -PO (OH) -,>
Hydrophilic groups such as PO- and -CN, preferably -PO (O
H) ₂ , —PO (OH) —,> PO—, which are pendantly bonded to a phosphate group or a carboxylic acid group. The incorporation of the hydrophilic polymer facilitates dissolution or swelling of the printing original plate by the aqueous developer, and the scraping means such as a brush causes the printing original plate to lose its shape.

When the photopolymerizable ethylenic monomer is irradiated with actinic light, it is entangled or bridged between the molecular chains of the elastomer and the hydrophilic polymer to cure the printing original plate, and its shape is destroyed by the developing solution. Disappear.

The photopolymerization initiator generates a radical upon irradiation with active light, and specifically, α-diketones such as diacetyl and benzyl; acyloins such as benzoin and pivaloin; benzoin methyl ether and benzoin ethyl ether. Acryloin ethers such as benzoin isopropyl ether; polynuclear quinones such as anthraquinone and 1,4-naphthoquinone;

The aqueous developer of the present invention is used as follows. First, the printing film is brought into close contact with the photosensitive printing original plate, and active light is irradiated from the printing film side. The printing film is obtained by printing a relief pattern on a printing plate. Usually, the exposed portion is a convex image portion and the unexposed portion is a concave image portion. Therefore, a necessary pattern is printed correspondingly. It is preferable to irradiate the back surface of the photosensitive printing original plate with active light before the printing film is brought into close contact with the printing film. The exposure of the back side increases the strength of the printing original plate and prevents the printing original plate from being deformed during operation. Since a base film and a cover film are closely laminated on the printing original plate with the printing original plate interposed therebetween in order to maintain the shape, it is preferable to peel off the film before exposure from the printing film side. When the film is exposed in a laminated state, the active light is scattered and absorbed in the film portion, and the active light does not reach the photosensitive printing original plate sufficiently. Attach the photographic printing film to the surface of the backside exposed printing plate in close contact. Gaps in the image result in blurry or distorted images. The method of irradiating the active light is not particularly limited. Usually a high pressure mercury lamp,
Use a lighting device such as a halogen lamp or an ultraviolet lamp. As the active light, one having a wavelength of 320 to 400 nm is usually used. By irradiating with active light, the exposed portion of the printing original plate is cured according to the pattern of the printing film. Next, the aqueous developing solution of the present invention is brought into contact with the printing original plate after being irradiated with the active light, and developed by rubbing with a brush or the like. Since the unexposed part of the actinic light is not cured,
Upon contact with the aqueous developing solution, the unexposed portion of the photosensitive composition constituting the original plate is dissolved or swelled and can be scraped off. The aqueous developer of the present invention is usually used in the temperature range of 5 to 80 ° C.

After development, the photosensitive printing original plate is irradiated with actinic light in order to cure the whole. When the development residue is left on the upper surface of the photosensitive printing original plate when the active light is irradiated,
The dross is cured by the actinic light and is fixed on the printing plate surface, which lowers the image reproducibility. Therefore, in the manufacturing method of the present invention,
After development, it is preferable to rinse the photosensitive printing original plate with an aqueous rinse solution. The method of rinsing with the aqueous rinse liquid is not particularly limited, but it is preferable to spray the aqueous rinse liquid onto the photosensitive printing original plate using a jet nozzle or the like for rinsing so as to efficiently remove development dust and the like. Examples of the aqueous rinse liquid include water such as tap water, industrial water, and groundwater, and preferably a chelating agent aqueous solution in which a chelating agent is dissolved in water.
By using the aqueous solution of the chelating agent, the tackiness of the development debris is lowered and the sticking to the plate surface can be effectively prevented. As the chelating agent, the same ones as those which can be used in the above-mentioned aqueous developing solution can be mentioned.

Further, it is preferable that air is blown onto the upper surface of the photosensitive printing original plate using a blower to remove water from the surface of the printing original plate and further blow off development dust. This is because if water bubbles or the like remain on the plate surface of the photosensitive printing original plate, the active light is scattered to cause uneven exposure and the image reproducibility is deteriorated. Draining means by heating may be employed, but the means by heating may cause errors in the dimensions of the printing original plate. Although it may be left at room temperature, it takes a long time to dry, and after water bubbles remain, it causes uneven exposure.

The printing original plate has been cured to some extent by the backside exposure and the exposure by bringing the printing film into close contact in the above-mentioned step, but there is an uncured portion in part. If printing is performed with the uncured portion left, the relief pattern may be missing or the image may be distorted. Therefore, in order to completely cure the uncured portion, it is preferable to irradiate the printing original plate with active light again.

[0025]

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

Reference Example 1 Styrene-butadiene-styrene block copolymer 40
Parts by weight, 60 parts by weight of phosphoric acid ester group-containing styrene-butadiene copolymer, 50 parts by weight of liquid polybutadiene, 2,6
After kneading 0.2 parts by weight of -di-t-butyl-p-cresol at 150 ° C using a kneader until the temperature became uniform, the kneader temperature was lowered to 120 ° C and 10 parts by weight of 1,6-hexanediol diacrylate. , 10 parts by weight of 1,6-hexanediol dimethacrylate, 3 parts by weight of benzoin methyl ether and 0.02 part by weight of methylhydroquinone were added and further kneaded to obtain a photosensitive composition. This photosensitive composition was placed in a frame mold having a spacer thickness of 3 mm and opened at the top and bottom, and a polyester film having a thickness of 0.1 mm was coated on the top and bottom of the opening of the frame mold, and a press machine was used to coat 110-110 mm. After heating and pressurizing at 130 ° C. and 150 kgf, it was cooled to obtain a photosensitive printing original plate having a total thickness of 3 mm.

Reference Example 2 A photosensitive printing original plate was obtained in the same manner as in Reference Example 1 except that a styrene-butadiene copolymer containing a carboxyl group was used instead of the styrene-butadiene copolymer containing a phosphate ester group used in Reference Example 1. It was

Comparative Example 1 The back side of the photosensitive printing original plate obtained in Reference Example 1 was subjected to ultraviolet exposure using a JE-A ₂ -SS type manufactured by JEOL Ltd.
Exposure was performed so that the thickness of the cured layer was about 1.5 mm.
By this exposure, the polyester film covering the back surface is adhesively fixed. Next, the unexposed surface (front surface)
The polyester film of 1 was peeled off, a negative film for reproducibility evaluation was brought into close contact with the surface, and this surface was exposed for 15 minutes using the ultraviolet exposure machine. The negative film was peeled off, and the unexposed portion was removed with a 2% aqueous solution of polyoxyethylene nonylphenyl ether (using tap water as a solvent) at a temperature of 50 ° C. The removal rate (development rate) of the unexposed portion is 0.
It was 03 mm / min. After that, it was dried at 70 ° C. for 20 minutes, and the surface from which the unexposed portion was removed was re-exposed for 10 minutes using the above-mentioned UV exposure machine to form a relief image. The photosensitive printing plate on which the relief image was formed was mounted on a drum of a printing machine and printing was performed. A large amount of development residue was adhered to the printing plate surface. At the initial stage of printing, the ink did not adapt to the photosensitive printing plate, so that the reproducibility of the image due to repelling and development scum was observed. As the number of printed sheets increases, the development residue that the photosensitive printing plate has become accustomed to the ink gradually comes off, so that the image reproducibility is improved, but perfect image reproducibility was not obtained.

Example 1 The back side of the photosensitive printing original plate obtained in Reference Example 1 was subjected to an ultraviolet exposure machine (JE-A ₂ -SS type manufactured by JEOL SEIKI).
Exposure was performed so that the thickness of the cured layer was about 1.5 mm.
Next, the polyester film on the unexposed surface (front surface) was peeled off, a negative film for reproducibility evaluation was brought into close contact with the surface, and this surface was exposed for 15 minutes using the ultraviolet exposure machine. The negative film was peeled off, and the unexposed portion was removed with a 2% polyoxyethylene nonylphenyl ether and 0.1% tetrasodium ethylenediaminetetraacetic acid aqueous solution (using tap water as a solvent) at a temperature of 50 ° C. Development speed is 0.14
mm / min. After that, tap water was sprayed onto the photosensitive printing original plate using a jet nozzle, and then air was sprayed using a blower to dry the surface. Re-exposure was carried out for a minute to form a relief image to obtain a photosensitive printing plate. The photosensitive printing plate on which the relief image was formed was mounted on a drum of a printing machine and printing was performed. Although the development dust was slightly fixed, the irregularity of the convex image portion was reduced.

Example 2 Polyoxyethylene nonylphenyl ether 2% and ethylenediaminetetraacetic acid tetrasodium 0.1 used in Example 1 were used.
% Aqueous solution, a 2% aqueous solution of fatty acid alkanolamide and a 0.2% aqueous solution of nitroso triacetate disodium (tap water was used as the solvent) was used to obtain a photosensitive printing plate in the same manner as in Example 1. The developing speed was 0.17 mm / min. Further, there was no sticking of development dust, and there was no decrease in image reproducibility.

Example 3 Polyoxyethylene nonylphenyl ether 2% used in Example 1 and ethylenediaminetetraacetic acid tetrasodium 0.1
% Fatty acid alkanolamide 1.5% instead of aqueous solution
Also, a photosensitive printing plate was obtained in the same manner as in Example 1 except that a 0.2% aqueous tartaric acid solution (tap water was used as the solvent) was used. The developing speed was 0.14 mm / min. Further, there was no sticking of development dust, and there was no reduction in image reproducibility due to development dust.

Example 4 A photosensitive printing plate was obtained in the same manner as in Example 1 except that the photosensitive printing plate precursor obtained in Reference Example 2 was used. Development speed is 0.0
It was 9 mm / min.

Example 5 Instead of the 2% polyoxyethylene nonylphenyl ether and 0.1% tetrasodium ethylenediaminetetraacetic acid aqueous solution used in Example 1, 1.5% sodium dioctylsulfosuccinate and 0.2% tartaric acid aqueous solution ( A photosensitive printing plate was obtained in the same manner as in Example 1 except that tap water was used as the solvent. The developing speed was 0.12 mm / min. Further, there was no sticking of development dust, and there was no reduction in image reproducibility due to development dust.

[0034]

By using the aqueous developing solution of the present invention, the developing speed of the photosensitive printing plate is increased. Further, the development scum and the tackiness of the surface of the photosensitive printing plate are reduced, the development scum is prevented from sticking to the printing plate surface, and the deterioration of the image reproducibility is prevented.

Claims (2)

[Claims] 1. An aqueous developer for a photosensitive printing plate comprising an aqueous solution containing a chelating agent and a surfactant. 2. A step of bringing a printing film into close contact with a photosensitive printing original plate, irradiating with actinic light from the side of the printing film, a step of peeling off the printing film and developing with the aqueous developer according to claim 1 to remove an unexposed portion, A process for producing a photosensitive printing plate, comprising the step of irradiating a developed photosensitive printing plate precursor with active light.