JP2852520B2 - Photosensitive lithographic printing plate - Google Patents

Description

The present invention relates to a photosensitive lithographic printing plate. More specifically, the present invention relates to a photosensitive lithographic printing plate provided with a photosensitive layer made of a polymer capable of photoreticulation and having improved adhesion to a support having a hydrophilic surface.

[Conventional technology]

Photocrosslinkable materials that are crosslinked by a cycloaddition reaction are well known, and many of them are used as main components of a photosensitive composition used for producing a photosensitive lithographic printing plate or the like. Among these cross-linking materials, a photo-crosslinkable polymer having a maleimide group in the side chain has a problem that the adhesion to a support or another layer is not good, though it is highly sensitive and useful as a photoresist. Has not been put to practical use. If the adhesiveness is poor, the image may be peeled off or damaged by a brush or the like during development, and sufficient printing durability cannot be obtained. Also, at the time of low exposure, this tendency is remarkable,
As a result, the sensitivity is reduced.

Attempts to improve adhesion have been made in Japanese Patent Application Laid-Open No. 62-78544.
As disclosed in JP-A-62-85255, an attempt was made to add a negative-acting diazo resin to a photosensitive layer, and as described in JP-A-62-85255, pores of an anodized film provided on an aluminum support were disclosed. Attempts have been made to obtain a bonding force by a physical anchor effect.

However, addition of the diazo resin to the photosensitive layer has problems such as lowering the sensitivity and impairing the stability of the pigment (coloring material) in the state of the coating liquid. Further, the method of enhancing the anchor effect on the surface of the support has a drawback that the non-image portion is liable to receive the ink during printing, and the printing stain is easily caused.

[Problems to be solved by the invention]

Accordingly, an object of the present invention is to provide a photosensitive lithographic printing plate that provides a lithographic printing plate with excellent printing performance while maintaining excellent sensitivity of a photoreticulated polymer having a maleimide group in a side chain. I do.

[Means for solving the problem]

According to the present invention, the above object can be solved by providing a negative-working diazo resin layer between a hydrophilic-treated support and a photosensitive layer having a photoreticulated polymer having a maleimide group in a side chain. This is based on knowledge.

That is, in the present invention, on a support having a hydrophilic surface, a negative-working diazo resin layer as an intermediate adhesive layer and a photosensitive layer having a photoreticulable polymer having a maleimide group in a side chain are provided. It is a photosensitive lithographic printing plate characterized by the following.

Examples of the polymer capable of photoreticulation having a maleimide group on a side chain used in the present invention include JP-A-52-988 (corresponding to U.S. Pat. No. 4,079,041), German Patent 2,626,769, and European Patent 21,019. No., European Patent 3,
No. 552 and Die Angewandte Makromolokulare C
hemie) 115 (1983), pp. 163 to 181. (Wherein R and R ₁ each independently represent an alkyl group having up to 4 carbon atoms, or R and R ₁ may together form a 5- or 6-membered carbocyclic ring And a polymer having a maleimide group represented by a side chain in JP-A-49-128991, JP-A-49-128992, JP-A-49-128993,
No. 50-5376, No. 50-5377, No. 50-5379, No. 50-53
No. 78, No. 50-5380, No. 53-5298, No. 53-5299, No.
53-5300, 50-50107, 51-47940, 52-1390
No. 7, No. 50-45076, No. 52-121700, No. 50-10884
No. 50-45087, German Patent No. 2,349,948, No. 2,61
The following general formula (II) described in each specification of No. 6,276 (Wherein R ₂ represents an aromatic group, and R ₃ represents a hydrogen atom, a halogen atom, an alkyl group or a cyano group), and a polymer having a maleimide group in the side chain. The average molecular weight of these polymers is 1000
As mentioned above, it is preferably 30,000 to 40,000. These polymers have an average of two or more maleimide groups per molecule in the side chain. Among these polymers having a maleimide group in the side chain, a polymer having an acid group is particularly advantageous from the viewpoint of preventing pollution since alkaline water can be used during development. The acid value of the maleimide group polymer having an acid group is preferably in the range of 20 to 250, and more preferably in the range of 50 to 150. In particular, among polymers having these acid numbers, Die Angewandte M.
A copolymer of N- [2- (methacryloyloxy) ethyl] -2,3-dimethylmaleimide and methacrylic acid or acrylic acid as described on pages 71 to 91 of Akromolekulare Chemie 128 (1984) is useful. is there. Further, a multi-component copolymer suitable for the purpose can be easily synthesized by copolymerizing the vinyl monomer of the third component in synthesizing the copolymer. For example, by using an alkyl methacrylate or an alkyl acrylate whose homopolymer has a glass transition temperature of room temperature or lower as the vinyl monomer of the third component, flexibility can be given to the copolymer.

The photosensitizer optionally used in the present invention is 30
Triplet sensitizers having a maximum absorption that actually allows sufficient light absorption in the range of 0 nm or more are preferred. Examples of such a sensitizer include thioxanthone, a thioxanthone derivative, for example, 2-chlorothioxanthone, 2-isopluriuthioxanthone, dimethylthioxanthone, methylthioxanthone-1-ethylcarboxylate, and 5-nitroacenaphthene. . In addition to this,
Electron accepting compounds such as 1,2-dicyanobenzene, chloranil, and 2,3-dichloro-5,6-dicyanobenzoquinone described in 206425 are also effective. The addition amount of these sensitizers is 1 to 20% by weight, more preferably 3 to 10% by weight of the total composition.

In addition to the above, it is preferable to further add an antioxidant to the photosensitive layer, for example, di-t-butyl-p-cresol,
Benzoquinone, 4,4'-thiobis (3-methyl-6-t
-Butylphenol), 2-mercaptobenzimidazole, and the like are useful, and in some cases, a dye or pigment for the purpose of coloring the photosensitive layer, or a photoacid generator (for example, a triazine-based or oxazole-based trihalomethyl compound) as a printing agent. And a pH indicator, an azide compound, a leuco dye and a spiropyran compound.

The photosensitive composition as described above can be used alone or in a suitable solvent such as 2-methoxyethanol, 2-methoxyethyl acetate, propylene glycol monomethyl ether, 3-methoxypropanol, 3-methoxypropyl acetate, methyl ethyl ketone, and ethylene dichloride. These are dissolved in an appropriately combined solvent mixture and coated on a support. The coating amount is about 0.1g by weight after drying
/ m ² ~ about a range of 10 g / m ² are suitable, more preferably 0.5
It is a ~5g / m ^2.

The support having a hydrophilic surface used in the present invention is preferably a dimensionally stable plate. Such dimensionally stable plate-like materials include those conventionally used as supports for printed matter, and they can be suitably used in the present invention. Such supports include paper, plastics (eg, polyethylene, polypropylene,
Paper laminated with polystyrene, etc.), metal plates such as aluminum (including aluminum alloy), zinc, copper, etc., cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose acetate, cellulose acetate butyrate, cellulose nitrate , A plastic film such as polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc .; a paper or a plastic film on which a metal as described above is laminated or vapor-deposited; Among these supports, the aluminum plate is preferable because it is extremely dimensionally stable, is inexpensive, and has particularly good adhesion to the composition of the present invention. Further, a composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in JP-B-48-18327 is also preferable.

Also, in the case of a support of metal, especially aluminum,
It is preferable that a surface treatment such as a graining treatment and an anodizing treatment is performed.

Further, in order to enhance the hydrophilicity of the surface, it is preferable to perform a dipping treatment in an aqueous solution of sodium silicate, potassium fluorozirconate, phosphate or the like. US Patent 2,714,06
As described in the specification of Japanese Patent No. 6, as described in Japanese Patent Publication No. 47-5125, an aluminum plate immersed in an aqueous solution of sodium silicate after graining is subjected to anodizing treatment. Those immersed in an aqueous solution of a metal silicate are also preferably used.

Also, silicate electrodeposition as described in US Pat. No. 3,658,662 is effective.

Further, a support provided with electrolytic grains as disclosed in JP-B-46-27481, JP-A-52-58602 and JP-A-52-30503, and the above-described anodizing treatment and sodium silicate Surface treatments that combine treatments are also useful.

Further, it is also preferable to sequentially perform brush grain, electrolytic grain, anodizing treatment and sodium silicate treatment as disclosed in JP-A-56-28893. Further, after these treatments are performed, a water-soluble resin, for example, a polyvinyl sulfonic acid, a polymer or a copolymer having a sulfonic acid group in a side chain, a polyacrylic acid, or the like, is preferably undercoated.

These hydrophilic treatments are performed not only to make the surface of the support hydrophilic, but also to prevent harmful reaction with the photosensitive composition provided thereon, It is performed for the improvement of the quality. Things.

As the negative-working diazo resin existing as the intermediate adhesive layer, various known products can be used. Such diazo resins include 4-diazo-diphenylamine, 1-diazo-4-4-N, N-dimethylaminobenzene, 1-diazo-4-N, N-diethylaminobenzene, 1-diazo-4
-N-ethyl-N-hydroxyethylaminobenzene,
1-diazo-4-N-methyl-N-hydroxyethylaminobenzene, 1-diazo-2,5-diethoxy-4-benzoylaminobenzene, 1-diazo-4-N-benzylaminobenzene, 1-diazo-4 -N, N-dimethylaminobenzene, 1-diazo-4-morpholinobenzene, 1-diazo-2,5-dimethoxy-4-p-trimercaptobenene, 1-diazo-2-ethoxy-4-N, N
-Dimethylaminobenzene, p-diazo-dimethylaniline, 1-diazo-2,5-dibutoxy-4-morpholinobenzene, 1-diazo-2,5-diethoxy-4-morpholinobenzene, 1-diazo-2, 5-dimethoxy-4
-Morpholinobenzene, 1-diazo-2,5-diethoxy-4-morpholinobenzene, 1-diazo-2,5-diethoxy-4-p-tolylmercaptobenzene, 1-diazo-3-ethoxy-4-N -Methyl-N-benzylaminobenzene, 1-diazo-3-chloro-4-N, N-diethylaminobenzene, 1-diazo-3-methyl-4-
Pyrrolidinobenzene, 1-diazo-2-chloro-4-N,
N-dimethylamino-5-methoxybenzene, 1-diazo-3-methoxy-4-pyrrolidinobenzene, 3-methoxy-4-diazodiphenylamine, 3-ethoxy-4
-Diazodiphenylamine, 3- (n-propoxy)-
4-diazodiphenylamine, 3-isopropoxy-4
A diazo monomer such as diazodiphenylamine;
A condensing agent such as formaldehyde, acetaldehyde, propionaldehyde, butylacetaldehyde, isobutyraldehyde, or benzaldehyde is used at a molar ratio of 1: 1 to 1: 0.5 to preferably 1: 0.8 to 1: 0.6, respectively. A reaction product of a condensate obtained by condensation with an anion is exemplified. Examples of anions include tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitroortho-toluenesulfonic acid,
Sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, Dodecylbenzenesulfonic acid, 1-naphthol-5-sulfonic acid, 2-methoxy-
4-hydroxy-5-benzoyl-benzenesulfonic acid, paratoluenesulfonic acid Y ₂ ZnCl ₂ , and the like can be given. Among them, alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, and 2,5-dimethylbenzenesulfonic acid are particularly preferable.

The thickness of the diazo resin layer can be varied over a wide range, but it must be a thickness that allows a uniform bond-forming reaction with the upper photosensitive layer upon exposure.

Usually a dry solid with a good coating rate of 1 to 50 mg / m2, 5 to ²
0 mg / m ² is particularly good.

In addition, phosphoric acid, phosphorous acid, tartaric acid, citric acid, malic acid, dipicolinic acid, polynuclear aromatic sulfonic acids and salts thereof, sulfosalicylic acid, etc. are required as diazo resin stabilizers in the diazo resin layer and the photosensitive layer. It can be added according to.

A metal halide lamp comprising the photosensitive lithographic printing plate of the present invention;
An image is exposed using a light source rich in ultraviolet rays such as a high-pressure mercury lamp, the unexposed portion of the photosensitive layer is removed by processing with a developing solution, and finally a gum solution is applied to obtain a lithographic printing plate. After development, post-exposure may be performed to further increase the printing durability. Preferred as the developer are alkaline aqueous solutions containing a small amount of an organic solvent such as benzyl alcohol, 2-phenoxyethanol and 2-butoxyethanol, for example, U.S. Patent Nos. 3,475,171 and 3,615,480.
Can be mentioned. Furthermore,
JP-A-50-26601, JP-B-56-39464, JP-B-56-42860
The developer described in each of the publications is also excellent as a developer for the photosensitive lithographic printing plate of the present invention.

〔The invention's effect〕

The photosensitive lithographic printing plate of the present invention provides a lithographic printing plate having high sensitivity and excellent printing durability.

〔Example〕

 Hereinafter, the present invention will be described in more detail based on examples.

Example 1 A 0.30 mm thick aluminum plate was coated with a nylon brush and 400
The surface was sand-grained using an aqueous suspension of mesh pumistone, and then thoroughly washed with water. After being immersed in 10% sodium hydroxide at 70 ° C. for 60 seconds for etching, washed with running water, washed with 20% HNO ₃ for neutralization and washed with water. This is V _A = 12.7V
The electrolytic surface roughening treatment was performed in a 1% nitric acid aqueous solution at an anode-time electricity quantity of 160 coulomb / dm ² using a sine wave alternating current under the above conditions. When the surface roughness was measured, it was 0.6μ (R
a display). Subsequently, after immersion in a 30% H ₂ SO ₄ aqueous solution and desmutting at 55 ° C. for 2 minutes, 20% H ₂ SO ₄
In an aqueous solution, anodizing was performed for 2 minutes so that the thickness became 2.7 g / m ² at a current density of 2 A / dm ² . Thereafter, it was immersed in a 2.5% aqueous solution of sodium silicate at 70 ° C. for 1 minute, washed with water, and dried.

 Next, the following diazo resin liquid was prepared.

This solution was applied to the above substrate using a spin coater so that the weight after drying was 10 mg / m ² .

 Then, it was dried at 80 ° C. for 1 minute.

 Next, the following photosensitive composition I was prepared.

The photosensitive composition was dried on a substrate provided with the above diazo resin using a spin coater, and dried to a weight of 1.5 g / m ^2.
It applied so that it might become.

 Then, it was dried at 80 ° C. for 2 minutes.

 The printing plate thus obtained is designated as A.

(Comparative Example) A printing plate B was obtained by applying and drying this photosensitive solution to a dry weight of 1.5 g / m ² on the same substrate as in Example 1 without providing a diazo resin layer.

Step wedges (density step 0.15,
(15 steps of density), and exposure was performed 10 times with a printer (2KW metal halide lamp) manufactured by Nuark, USA. After exposure, the plate was developed with the following developer at 25 ° C. for 1 minute to obtain a printing plate.

Developer Benzyl alcohol 4.5 g 38% aqueous solution of sodium salt of isopropyl naphthalene sulphonic acid 4.5 g Triethanolamine 1.5 g Monoethanolamine 0.1 g Sodium sulfite 0.3 g Pure water 100 g The printing plate A of the present invention has a firm image and high sensitivity, but B has poor adhesion to the substrate, so that not only the sensitivity is low, but also the image portion has scratches when slightly rubbed during development. There were countless.

When these printing plates were attached to a Heidel SOR printing machine and printed, A was able to obtain 50,000 copies, but B had 1,000 prints, the detail was skipped, and tone reproduction was poor. Only a sample was obtained, and the entire image was rubbed at 10,000 sheets.

[Example 2] The following diazo resin liquid was applied to the same substrate used in Example 1 and dried. The dry weight was adjusted to 10 mg / m ² .

Next, the following photosensitive solution II was prepared.

The photosensitive composition was applied to the substrate to which the diazo resin had been applied using a spin coater so that the weight after drying was 1.5 g / m ² . This printing plate was designated as C.

(Comparative Example 2) a PF ₆ salt of a condensate of P- diazo diphenylamine with formaldehyde into the photosensitive solution II was added 0.2 g, photosensitive liquid I
Made II.

Without providing a diazo resin layer on the substrate used in Example 1,
Photosensitive solution III was applied and dried. Dry weight was 1.5 g / m ^2. This printing plate was designated as D.

Further, when this photosensitive solution III was allowed to stand in a room overnight, sedimentation of the pigment occurred at the bottom.

(Results) The results of exposure and development are shown in the same manner as in Example 1. or,
This shows the number of printings obtained during the printing time.

The printing plate C of the invention had higher sensitivity and higher printing durability. Also, the stability of the coating solution was excellent.

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-62-294238 (JP, A) JP-A-62-85255 (JP, A) JP-A-55-160010 (JP, A) JP-A-59-1985 208552 (JP, A) JP-A-59-53836 (JP, A) JP-A-53-145706 (JP, A) JP-B-50-7481 (JP, B1)

Claims (1)

(57) [Claims] 1. A negative working diazo resin layer having a thickness of 5 to ²⁰ mg / m ² as an intermediate adhesive layer on a support having a hydrophilic surface, and a photoreticulation having a maleimide group in a side chain. A photosensitive lithographic printing plate comprising a photosensitive layer having a polymer.