JPH09236912A - Original plate of photosensitive planographic printing plate and photomechanical process therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart plate inspectability without using a dyeing soln. in a photomechanical process for an original plate with a hydrophilic swellable layer on the substrate by incorporating a dye or its precursor. SOLUTION: This original plate contains a dye or its precursor. A leuco dye may be used as the dye or its precursor. This leuco dye is a colorless or light-colored substance and forms a deep color by contact with an electron accepting substance such as bisphenol A. The dye or its precursor can be allowed to form a color in a photomechanical process, e.g. after or during development. The leuco dye can be allowed to form a color by an acid or a phenolic compd. known as an electron accepting substance, e.g. clayish acid such as acid clay or kaolin or oxalic acid.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to improvement of practical characteristics of a novel photosensitive lithographic printing plate precursor, and particularly to a photosensitive lithographic printing plate precursor which is excellent in plate inspection property and does not require a dyeing step with a dyeing solution. And its plate making method.

[0002]

BACKGROUND OF THE INVENTION The present invention relates to an improvement of a novel photosensitive lithographic printing plate precursor having at least a hydrophilic swelling layer on a substrate.

This novel photosensitive lithographic printing plate precursor is usually
A printing plate is formed by exposing and developing, but it is difficult to distinguish between the image area, which is the ink inking area, and the non-image area, which is the ink repulsion area, and it is confirmed that the original image is reproduced. However, there is a problem that it is difficult to confirm the end point of the development, it is difficult to perform the correction work, and the so-called plate inspection property is poor. Further, there is a problem that it is difficult to check an appropriate ink supply amount at the time of printing using a plate image area reader.

In order to improve the plate inspection property, a visible image is generally obtained by dyeing an image area or a non-image area with a dye-containing dyeing solution after or during development.

However, the treatment with a dyeing solution containing a dye has a problem that hands, clothes, and an automatic developing machine are contaminated when the dyeing solution is replenished or the dyeing solution is replaced.

Therefore, the inventors of the present invention have made earnest studies as to a method not using a dyeing solution while considering the plate inspection property. As a result, the original plate is made to contain a dye or a leuco dye as a dye precursor in advance, The present invention has been found to selectively develop color only in image areas or non-image areas during plate making such as after development or during development.

[0007]

An object of the present invention is to provide plate inspection property without using a dyeing solution when plate-making a photosensitive lithographic printing plate precursor having at least a hydrophilic swelling layer on a substrate. To do.

[0008]

That is, the present invention has the following configuration.

(1) A photosensitive lithographic printing plate precursor comprising at least a hydrophilic swelling layer on a substrate, which contains a dye or a dye precursor.

(2) The photosensitive lithographic printing plate precursor as described in (1) above, wherein the dye or dye precursor is a leuco dye.

(3) The photosensitive lithographic printing plate precursor as described in (1) above, wherein a dye or a dye precursor is contained in the hydrophilic swelling layer.

(4) A photosensitive lithographic printing plate precursor as described in any one of (1) to (3) above, which is characterized in that a dye or a dye precursor is developed when the photosensitive lithographic printing plate precursor according to any one of (1) to (3) is prepared. Plate making method.

(5) The method of making a photosensitive lithographic printing plate precursor as described in (4) above, wherein color is developed by a treatment liquid containing an acid or a phenolic compound.

(6) The method of making a photosensitive lithographic printing plate precursor as described in (4) above, wherein the image areas or the non-image areas are colored.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The photosensitive lithographic printing plate precursor according to the invention contains a dye or a dye precursor. As the dye or dye precursor, a leuco dye (leuco dye) can be used. The leuco dye itself is a colorless or light-colored substance, but has a property of developing a dark color when brought into contact with an electron-accepting substance such as bisphenol A, and the following substances are used. .

(1) Triphenylmethane type leuco body 3,3-bis (p-dimethylaminophenyl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6
-Dimethylaminophthalide (CVL), 3,3-bis (p-dimethylaminophenyl) -6-diethylaminophthalide, 4-hydroxy-4'-dimethylaminotriphenylmethanelactone, 4,4'-bisdihydroxy- 3,3′-Bisdiaminotriphenylmethanelactone (2) Fluoran-based leuco body 3-dimethylamino-6-methoxyfluorane, 3,6
-Bis-β-methoxyethoxyfluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3,7
-Bisdiethylaninofluorane, 3-diethylamino-7-methoxyfluorane (3) spiropyran-based leuco body 3-phenyl-8'-methoxybenzoindolinospiropyran, 8'-methoxybenzoindolinospiropyran, 4,7, 8'-trimethoxybenzoindolino spiropyran (4) auramine-based leuco body 4,4'-bisdimethylamino-3,4-chlorophenylauramine, 4,4'-bisdimethylaminopiperazinehydrol (5) phenothiazine The leuco system of the system p-methoxybenzoyl leuco methylene blue The various types described above are used, and can be selected according to various color tones. Further, two or more kinds may be used in combination.

These leuco dyes are preferably contained in the hydrophilic swelling layer, and the content relative to the hydrophilic swelling layer is preferably 0.1 to 50% by weight, more preferably 0.1.
1 to 30% by weight.

The dye or dye precursor can be colored during the plate making of the photosensitive lithographic printing plate precursor, for example, after or during development. The leuco dye can be colored with an acid or a phenolic compound.

The acid or phenolic compound is known as an electron accepting substance, and examples thereof include clay such as acid clay, kaolin and zeolite, oxalic acid, maleic acid, citric acid, stearic acid and benzoic acid. acid,
Examples include organic acids such as gallic acid, and the following phenolic compounds.

Catechol, resorcin, hydroquinone,
α-naphthol, β-naphthol, 3,5-xylenol, timol, pyrogallol, phloroglucin, phloroglucincarboxylic acid, 4-tert-butylphenol, 4-phenylphenol, 4-hydroxydiphenoxide, 4-hydroxyacetophenone, Methyl-4-
Methyl benzoate, 4-tert-octylcatechol, 4,4′-secondary-butylidene diphenol,
2,2'-dihydroxydiphenol, 4,4'-isopropylidene diphenol (bisphenol A), 2,
2'-methylenebis (4-methyl-6-tert-butylphenol), 4,4'-cyclohexylidenephenol, 4,4'-isopropylidenebis (2-chlorophenol), other phenolformaldehyde, novolac type phenol resin A halogenated novolac type phenolic resin or the like can also be used.

The above-mentioned acid or phenolic compound may be used alone or in combination of two or more kinds. Further, it can be diluted with a solvent such as water and used as a treatment liquid. In that case, the acid or phenolic compound added is preferably 0.1% by weight to 50% by weight, more preferably 1.0% by weight. % To 30% by weight.

The pH of this treatment liquid is 0.5 to 5.0.
Is preferable, and more preferably 1.0 to 3.5.

Further, a buffer or a salt, a known organic solvent, a surfactant, etc. can be added to the treatment liquid.

The liquid temperature of the treatment liquid is preferably 10 to 50 ° C, more preferably 20 to 40 ° C. The treatment time can be appropriately selected depending on the treatment temperature, but is usually 3 seconds to 120 seconds, and preferably 10 seconds to 60 seconds.

The plate may be coated with the treatment liquid by a known method, for example,
Examples thereof include a method of immersing in a vat or the like, a method of showering the plate surface, and the like. Further, it is also possible to improve the uneven coloring by performing the treatment while rubbing with a brush or the like or by performing the treatment while generating ultrasonic waves.

The hydrophilic swelling layer of the photosensitive lithographic printing plate precursor according to the invention will be described.

The hydrophilicity in the present invention means the property of being substantially insoluble in water and exhibiting water swelling property. A known hydrophilic polymer is laminated on a substrate by coating or transfer, and the like. A hydrophilic swelling layer which is cross-linked or pseudo-cross-linked using the method described above and insolubilized in water to make it water-swellable is used.

The hydrophilic polymer referred to herein is a known water-soluble polymer (meaning that it is completely soluble in water), pseudo-water-soluble polymer (meaning that it is amphipathic, and macro-soluble but micro-soluble). Means a polymer containing a non-dissolved portion) and a water-swellable polymer (meaning a polymer that swells in water but does not dissolve). That is, it means a polymer that adsorbs or absorbs water under normal use conditions, and a polymer that dissolves in water or swells in water.

In the present invention, known polymers can be used as the hydrophilic polymer, and include animal polymers, plant polymers, and synthetic polymers. For example, "Function
al Monomers ”(Y. Nyquist, De
Kker), "Water-soluble polymer" (Nakamura, Chemical Industry Co., Ltd.), "The latest processing and modification technology of water-soluble polymer water-dispersible resin and application development comprehensive technical data collection" (Business Development Center Publishing Department), Hydrophilic polymers described in "Applications and markets of new water-soluble polymers" (CMC) and the like can be mentioned.
Specific examples are given below.

(A) Natural polymers Starch-acrylonitrile graft polymer hydrolyzate, starch-acrylic acid graft polymer, starch-styrene sulfonic acid graft polymer, starch-
Vinyl sulfonic acid type graft polymer, starch-acrylamide type graft polymer, carboxylated methyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, cellulose xanthate, cellulose-acrylonitrile type graft polymer, cellulose-styrene sulfonic acid type graft polymer , Carboxymethyl cellulose cross-linked product,
Hyaluronic acid, agarose, collagen, milk casein, acid casein, rennet casein, ammonia casein, potash casein, borax casein, glue, gelatin, gluten, soy protein, alginate, ammonium alginate, potassium alginate, sodium alginate arabia gum , Tragacanth gum, karaya gum, guar gum, locust bean gum, Irish moss,
Soy lecithin, pectic acid, starch, carboxylated starch, agar, dextrin, mannan, etc.

(B) Synthetic Polymers Polyvinyl alcohol, polyethylene oxide, poly (ethylene oxide-co-propylene oxide), aqueous urethane resin, water-soluble polyester, ammonium polyacrylate, sodium polyacrylate, ammonium polymethacrylate, Acrylic copolymer, acrylic emulsion copolymer, polyvinyl alcohol cross-linked polymer, sodium polyacrylate cross-linked product, polyacrylonitrylyl saponified polymer, hydroxyethyl (meth) acrylate-based polymer ((meth) □ □
□□ stands for □□□□ or meta □□□□. ), Poly (vinyl methyl ether-co-maleic anhydride), maleic anhydride copolymer, vinylpyrrolidone copolymer, polyethylene glycol di (meth)
Acrylate-based crosslinked polymers, polypropylene glycol di (meth) acrylate-based crosslinked polymers and the like.

The above-mentioned hydrophilic compound may contain a monomer or a copolymerization component having different substituents for the purpose of imparting flexibility or controlling the hydrophilicity as long as the effect of the invention is not changed. is there.

Next, the method of crosslinking the hydrophilic polymer will be described.

The hydrophilic swelling layer is obtained by cross-linking or pseudo-cross-linking at least one kind of the above-mentioned hydrophilic polymer, if necessary.
A layer is formed on the substrate by making it insoluble in water. Usually, the cross-linking reaction is performed by three-dimensional cross-linking reaction utilizing the reactive functional group of the hydrophilic polymer.

The crosslinking reaction may be covalent crosslinking or ionic crosslinking.

Examples of the compound used in the crosslinking reaction include known polyfunctional compounds having a crosslinking property, such as polyepoxy compounds, polyisocyanate compounds, poly (meth) acrylic compounds, polymercapto compounds, polyalkoxysilyl compounds, Examples thereof include polyvalent metal salt compounds, polyamine compounds, aldehyde compounds, polyvinyl compounds and the like. The crosslinking reaction is carried out by adding a known catalyst to accelerate the reaction.

These hydrophilic polymers can be used as a single substance or as a mixture of two or more kinds for the purpose of maintaining the shape of the hydrophilic swelling layer and adjusting the water swelling property, and a non-hydrophilic polymer is blended. It is also possible.

It is also possible to add a small amount of various additives such as dyes and pigments, surfactants and organic acids to the hydrophilic swelling layer used in the present invention.

Next, an example of the method for producing the photosensitive lithographic printing plate precursor according to the invention will be described, but the invention is not limited thereto.

The image of the photosensitive lithographic printing plate precursor of the present invention is
For example, it can be formed by irradiating the surface of the plate with an actinic ray. That is, the difference between the image area and the non-image area is caused by the irradiation of the actinic ray.

Preferably, it is prepared by negative working image formation. That is, a portion of the hydrophilic swelling layer which is not irradiated with actinic rays (hereinafter referred to as an unexposed portion)
The initial elastic modulus of the portion irradiated with actinic rays (hereinafter referred to as the exposed area) is higher than that of the ink, resulting in the ink receptive image area, and the unexposed area is the ink repellent non-image area. Becomes

Known photosensitive compounds are used for such image formation.

That is, the hydrophilic swelling layer of the photosensitive lithographic printing plate precursor is allowed to contain a known photocrosslinking or photocurable photosensitive compound to selectively crosslink and / or cure the exposed area to obtain an initial elastic modulus. Imaging is accomplished by raising.

Examples of known photocrosslinking or photocurable photosensitive compounds include the following specific examples (1) to (6).

(1) Photopolymerizable Monomer or Oligomer (2) Photodimerization Type Photosensitive Resin Composition (3) Composition Composed of Monomer, Oligomer or Polymer Having Epoxy Group and Known Photoacid Generator (4) Composition of monomer, oligomer or polymer having allyl group and / or vinyl group and monomer, oligomer or polymer having mercapto group (5) Composition of diazonium salt compound and hydroxyl group-containing compound (6) Bisazide Polyisoprene rubber or polybutadiene rubber cyclized with a compound, or a photosensitive composition containing cresol novolac resin as a main component.

These photosensitive compounds are added to the composition when the hydrophilic swelling layer is formed on the substrate so that they are present in the composition, or after the hydrophilic swelling layer is formed, the photosensitive composition is added to the composition. It is added using a method of coating on the layer and impregnating the layer.

Further, a known photosensitizer may be added to the hydrophilic swelling layer of the original plate for the purpose of sensitizing these photosensitive compounds.

The substrate of the photosensitive lithographic printing plate precursor used in the invention is not limited except that it must be flexible enough to be attached to an ordinary lithographic printing machine and capable of withstanding the load applied during printing. Absent.

As typical examples, aluminum, copper, iron,
Examples thereof include a metal plate, a plastic film such as a polyester film and a polypropylene film, coated paper, and a rubber sheet. Further, the substrate may be a composite of the above materials.

Further, the surface of the substrate may be subjected to various surface treatments such as electrochemical treatment, acid-base treatment and corona discharge treatment for the purpose of improving plate inspection property and adhesiveness.

It is also possible to form a primer layer by coating on these substrates for the purpose of improving the adhesiveness and preventing halation, and use them as substrates.

Next, the protective layer will be described.

On the surface of the photosensitive hydrophilic swelling layer of the photosensitive lithographic printing plate precursor of the invention, a protective layer which is removable for the purpose of protecting the hydrophilic swelling layer is coated on the hydrophilic swelling layer. It is preferably formed or laminated with a protective film.

These protective films are subjected to unevenness treatment in order to improve vacuum adhesion during image exposure,
It is also preferable to apply a matte treatment on the surface or to apply and laminate a plastic layer containing silica particles on the surface of the protective film.

Next, the method of exposing the photosensitive lithographic printing plate precursor according to the invention will be described.

The photosensitive lithographic printing plate precursor according to the present invention preferably becomes a printing plate through a plate making process for negative working. That is, image exposure is performed through a negative original image film by a normal exposure light source.

As the light source used in this exposure step,
For example, a high-pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp and the like can be mentioned.

Next, a method for making a photosensitive lithographic printing plate according to the present invention will be described.

In the plate-making process, when the protective layer is the laminated film mentioned in the above example, peeling and removal can be easily carried out by mechanical means such as a film peeling device or manual means for peeling by hand. In this developing step, when rinsed with water or a developing solution, the photosensitive compound and leuco dye present in the hydrophilic swelling layer in the unexposed area are dissolved or desensitized, and a dispersion structure suitable for ink repulsion and It becomes a non-image area having water swelling property, and the exposed area becomes an image area where the water swelling property is lower than that of the unexposed area due to photocrosslinking curing of the photosensitive compound. After the development, or during the development, the leuco dye in the image area can be colored by treating with the treatment liquid containing the acid or the phenolic compound.

Next, a printing method using the lithographic printing plate obtained from the photosensitive lithographic printing plate precursor according to the invention will be described.

A known lithographic printing machine is used for the lithographic printing of the present invention. That is, sheet-fed and rotary printing machines of the offset and direct printing type are used.

After image formation of the lithographic printing plate of the present invention,
Ink is attached to the plate cylinder of these planographic printing machines, and ink is supplied to the plate surface from an inking roller in contact therewith.

The non-image area having the hydrophilic swelling layer on the plate surface swells with the dampening water supplied from the dampening water supply device to repel the ink. On the other hand, the image area receives the ink and supplies the ink to the surface of the offset blanket cylinder or the surface of the printing medium to form a printed image.

As the dampening water used when printing the planographic printing plate of the present invention, it is of course possible to use the etchant used in PS plates with water, but pure water containing no additives at all. Can be used.

When printing is carried out using the lithographic printing plate obtained from the photosensitive lithographic printing plate precursor of the present invention, it is preferable to use pure water containing no additives.

The present invention will be described in more detail below with reference to examples.

[0067]

【Example】

Example 1 On an aluminum plate (made by Sumitomo Light Metal Co., Ltd.) having a thickness of 0.3 mm,
Sodium acrylate-n-butyl methacrylate copolymer (composition ratio 40/60 mol%) was used as the hydrophilic polymer, and the following composition was applied and heat-treated at 150 ° C. for 60 minutes to obtain 2 g / m ² A hydrophilic swelling layer having a thickness was applied.

(1) Hydrophilic polymer 28 parts by weight (2) Tetraethylene glycol diglycidyl ether 5 parts by weight (3) Aqueous latex “JSR0596” (carboxy modified styrene-butadiene copolymer latex: manufactured by Nippon Synthetic Rubber Co., Ltd.) ) 65 parts by weight (4) 2-aminopropyltrimethoxysilane 2 parts by weight (5) Purified water 900 parts by weight

On the hydrophilic swelling layer coated as described above, a photosensitive composition having the following composition containing a leuco dye was applied and heat-treated at 100 ° C. for 3 minutes to give a photosensitive composition of 0.5.
g / m ² was impregnated in the hydrophilic swelling layer.

Thereafter, a 12-micron-thick single-sided matted biaxially oriented polypropylene film was laminated with a calendar roller so that the non-matted surface was in contact with the hydrophilic swelling layer, and a negative type lithographic printing plate precursor was laminated. Got

The obtained lithographic printing plate precursor was a high pressure mercury lamp "Jetlight 3303kW: manufactured by Oak Manufacturing Co., Ltd."
After contact exposure (3.6 mW / cm ² ) for 90 seconds through a negative film having PCW (PLATE CONTOROL WEDGE: KALLE) attached thereto, the laminate film was peeled off. Then, the entire surface of the plate was rinsed with tap water to wash the unexposed area of the photosensitive composition, and the development step was completed.

(1) Crystal violet lactone (leuco dye) 10 parts by weight (2) CH ₂ ═CHCOO— (CH ₂ ) ₉ —OCOCH═CH ₂ 20 parts by weight (3) Michler's ketone 2 parts by weight (4) 2 , 4-diethylthioxanthone 2 parts by weight (5) "Isopar E" (isoparaffin hydrocarbon: manufactured by Esso Chemical Co., Ltd.) 66 parts by weight

The plate after the development process had poor plate inspection property, and the density difference between the image area and the non-image area was not clear. Therefore, the plate was treated with the following treatment liquid. In the processing method, the plate was immersed in a vat containing the processing liquid at 25 ° C. for 10 seconds. As a result, the photosensitive layer in the image area was colored blue. As a result of measuring the color density with a Macbeth reflection densitometer RD514, the density difference between the image area and the non-image area is 0.8, and a printing plate with excellent plate inspection property can be obtained, and the original negative film is reliably reproduced. I was able to confirm that it is doing.

Example 1 Composition of Treatment Solution Water 100 parts by weight Citric acid 10 parts by weight Potassium citrate 10 parts by weight Ethylenediaminetetraacetic acid 4 sodium 0.05 parts by weight Butylcarbitol 5 parts by weight Neugen EA112 (Daiichi Kogyo Seiyaku ( Co., Ltd., nonionic surfactant) 1 part by weight Sodium dodecylbenzene sulfonate (anionic surfactant) 1 part by weight

Example 2 A plate was prepared in the same manner as in Example 1 except that the developing solution and the color-developing process were simultaneously performed using the processing solution of Example 1. as a result,
It was confirmed that the density difference between the image area and the non-image area was 0.8, a printing plate excellent in plate inspection property was obtained, and that the original image film was reliably reproduced.

Example 3 A plate was prepared in the same manner as in Example 1 except that the processing liquid of Example 1 was changed to the following processing liquid. As a result, it was confirmed that the density difference between the image area and the non-image area was 0.75, a printing plate excellent in plate inspection property was obtained, and the original image film was reliably reproduced.

Example 3 Composition of Treatment Liquid 100 parts by weight of water 10 parts by weight of gallic acid 1 part by weight of sodium 2-ethylhexyl sulfate

Example 4 A plate was prepared in the same manner as in Example 1 except that the following processing solution was used instead of the processing solution of Example 1. As a result, it was confirmed that the density difference between the image area and the non-image area was 0.80, a printing plate excellent in plate inspection property was obtained, and the original image film was reliably reproduced.

Example 4 Treatment Liquid Composition Water 100 parts by weight Hydroquinone 10 parts by weight Butyl carbitol 2 parts by weight

[0080]

When the photosensitive lithographic printing plate precursor according to the invention is used, it is possible to obtain a printing plate excellent in plate inspection property by causing a color to develop during plate making.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location G03F 7/34 G03F 7/34 7/40 521 7/40 521

Claims (6)

[Claims] 1. A photosensitive lithographic printing plate precursor having at least a hydrophilic swelling layer on a substrate, which contains a dye or a dye precursor. 2. The photosensitive lithographic printing plate precursor as claimed in claim 1, wherein the dye or dye precursor is a leuco dye. 3. The photosensitive lithographic printing plate precursor according to claim 1, wherein a dye or a dye precursor is contained in the hydrophilic swelling layer. 4. A method of making a photosensitive lithographic printing plate precursor, which comprises causing a dye or a dye precursor to develop a color when the photosensitive lithographic printing plate precursor as claimed in claim 1 is formed. 5. The plate-making method of the photosensitive lithographic printing plate precursor as claimed in claim 4, wherein color is developed by a treatment liquid containing an acid or a phenolic compound. 6. The plate-making method for a photosensitive lithographic printing plate precursor as claimed in claim 4, wherein the image area or the non-image area is colored.