JPH0682212B2 - Waterless planographic printing plate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a master plate for waterless lithographic printing, which can be printed without using a fountain solution.

[Conventional technology]

Many waterless planographic printing plates have been proposed which allow printing without dampening water using a silicone rubber layer as an ink repellent layer. In particular, as shown in JP-A-55-110249, a support, a photosensitive image-forming layer containing a quinonediazide compound (hereinafter abbreviated as photosensitive layer), and a silicone rubber layer made of organopolysiloxane are laminated in this order. The waterless lithographic printing plate precursor is effective as a negative working plate for normal exposure. With regard to such a waterless lithographic printing plate precursor, the support and the photosensitive layer have so far been used for the purpose of preventing halation, securing the adhesive force between the support and the photosensitive layer, hiding the support by containing fine particles, and the like. It is common to provide a primer layer between the two.

[Problems to be solved by the invention]

The waterless planographic printing plate precursor thus constructed had the following problems in spite of its usefulness.

That is, when the film thickness of the photosensitive layer is increased, the developability deteriorates. On the contrary, when the film thickness is made smaller, the light absorption of the photosensitive layer becomes smaller. Therefore, when a large amount of image exposure is taken, the exposure light passes through the photosensitive layer and is reflected by the substrate or the primer layer so that the halation is performed. And the reproducibility of halftone dots deteriorates.

As a solution to this, it is possible to add a light absorber such as an ultraviolet absorber to the primer layer or the photosensitive layer, but in practice, it is difficult to match the light absorption wavelength between the light absorber and the quinonediazide group contained in the photosensitive layer. , The anti-halation effect is not great.

The inventors of the present invention have made earnest studies on measures for increasing the anti-halation effect of the primer layer in view of the above-mentioned drawbacks of the prior art, and as a result, have found the following solution and arrived at the present invention.

[Means for solving problems]

That is, the present invention is a waterless lithographic printing plate precursor in which a support, a primer layer, a photosensitive image-forming layer containing a quinonediazide compound, and a silicone rubber layer are laminated in this order, and the primer layer has a quinonediazide group of 0.01 to twenty five
The present invention relates to a waterless lithographic printing plate precursor, which is characterized by containing by weight%.

The support in the present invention is not particularly limited, but may be any support as long as it is used in a known waterless lithographic printing plate precursor. Examples thereof include metal plates such as aluminum, iron and zinc, organic polymer films such as polyester, polyamide and polyolefin, and composites thereof.

The quinonediazide group contained in the primer layer used in the present invention acts as a light absorber to bring about an antihalation effect. As the content of the quinonediazide group in the primer layer, if it is too small, it is difficult to obtain the antihalation effect, and if it is too large,
Since it is economically disadvantageous, it is necessary to contain 0.01 to 25% by weight, more preferably 0.05 to 10% by weight, and most preferably 0.1 to 5% by weight.

Examples of the quinonediazide group include a substituted or unsubstituted 1,2-benzoquinonediazide group, a 1,2-naphthoquinonediazide group, and a 2,1-naphthoquinonediazide group. Among them, from the viewpoint of stability, it is desirable to contain a 1,2- or 2,1-naphthoquinonediazide group.

Examples of the compound having a quinonediazide group include a compound in which a 1,2-benzoquinonediazide group is bonded via a carbon atom at the 4-position or 5-position, and a 1,2- (or 2,1-) naphthoquinonediazide group having 4 groups. Compounds bonded via the carbon atom at position 5 or 5 may be mentioned. Among them, preferred are naphthoquinone diazide carboxylic acid, naphthoquinone diazide sulfonic acid halide, and esterified products of naphthoquinone diazide sulfonic acid and phenolic hydroxyl group. Among them, more preferred is 1,2 (or 2,1-) naphthoquinonediazide-4.
(Or 5) -esterified products of sulfonic acid and a compound having a phenolic hydroxyl group as described below are mentioned.

Substituted or unsubstituted phenol, cresol, dihydroxybenzene, pyrogallol, naphthol, bisphenol A, dihydroxynaphthalene, hydroxystyrene polymer (or copolymer), α-methylhydroxystyrene polymer (or copolymer), phenol resin (For example, phenol / formaldehyde addition condensate, cresol / formaldehyde addition condensate, phenol / acetone addition condensate, cresol / acetone addition condensate, pyrogallol / acetone addition condensate, cardanol / formaldehyde addition condensate, etc.), polyhydroxyphenyl .

As the primer layer, the compounds as described above can be used alone, but from the viewpoint of solvent resistance to a developing solution and adhesion to a support, it is desirable to contain a polymer having a crosslinked structure, and It is desirable that the acetone-soluble component is less than 20% by weight. Here, the acetone-soluble component refers to a component dissolved in acetone after stirring for 6 hours in a large excess of acetone at 25 ° C.

The polymer used for the primer layer is an addition polymer (for example, a poly (meth) acrylic acid ester derivative,
Polystyrene derivative, polydiene derivative, polyethylene derivative, polyvinylidene derivative, polyvinylene derivative,
Polyvinyl alcohol derivatives and copolymers thereof, polycondensates (for example, polyester, polyimide, etc.), addition condensates (novolak resins, resole resins),
Amino resin (melamine resin, urea resin, etc.), polyether, polythiol, polyurethane, epoxy resin, alkyd resin, etc. may be arbitrarily selected in a form capable of forming a crosslinked structure. Here, the polymer having a glass transition point of 0 ° C. or lower is contained in the primer layer in an amount of 30% by weight or more,
It is preferable in terms of plate surface strength of the obtained printing plate, and as the polymer satisfying the above glass transition point, polyurethane, polyester, poly (meth) acrylic acid ester derivative, polyvinyl alcohol derivative alone or in a mixture is preferable. As the cross-linking method, a known polymer cross-linking method is selected, and at least one of polyvalent epoxy compounds, polyvalent isocyanate compounds and amino resins is used.
It is desirable to crosslink with a class of compounds.

In the primer composition as described above, for the purpose of improving the plate inspection property,
It is possible to add a white pigment such as titanium oxide or calcium carbonate, or a yellow pigment.

Although the thickness of the primer layer is arbitrary, it is disadvantageous in terms of coatability and economy that are too large, and when it is small, it is also disadvantageous in coatability, and is 0.5 μm to 100 μm, more preferably Is selected in the range of 1 to 30 microns. Further, a resin layer containing a polymer as a main component can be provided between the primer layer having the characteristics of the present invention and the support.

Examples of the quinonediazide compound contained in the photosensitive layer include compounds contained in the above-mentioned primer layer, but in terms of image forming property, it is preferable that 50% by weight or more of the quinonediazide compound has a molecular weight of 500 or more, and As the compound having a molecular weight of 500 or more, an esterified product of 1,2-naphthoquinonediazide-4 (or 5) -sulfonic acid and a compound having a phenolic hydroxyl group as shown below is used alone or in a mixture.

(1) Phenolic resin (for example, phenol / formaldehyde addition condensate, phenol / acetone addition condensate,
Cresol / formaldehyde addition condensate, cresol / acetone addition condensate, pyrogallol / acetone addition condensate, cardanol / formaldehyde addition condensate, cardanol / acetone addition condensate, etc. (2) Substituted or unsubstituted hydroxystyrene polymer (or Copolymer), substituted or unsubstituted α-methylhydroxystyrene polymer (or copolymer) (3) As described in JP-A-56-80046, a polyvalent isocyanate compound, a polyvalent epoxy compound, etc. The above-mentioned (1) and (2) are cross-linked. Further, the photosensitive layer may contain other polymers and plasticizers for the purpose of improving coating film forming property and adhesiveness.

The amount of the quinonediazide group in the photosensitive layer is arbitrary, but is preferably more than 5% by weight, more preferably 10% by weight.
It is recommended that the amount exceed. From the standpoint of developability, the acetone-soluble component of the photosensitive layer is preferably 20% by weight or more.

The thickness of the photosensitive layer is arbitrary, but if the thickness is too large, there is a problem that the developability deteriorates, and if the thickness is too small, there is a problem that pinholes are likely to occur. As described above, the thickness of the photosensitive layer is preferably 0.3 to 10 g / m ² , and more preferably 0.5 to 5 g / m ² .

In order to incorporate the quinonediazide compound into the primer layer, the following method is exemplified.

(1) A compound containing a quinonediazide group is added to the composition of the primer layer to apply the primer layer.

(2) Including a rubber component in the composition of the primer layer,
Apply the primer layer. Then, a composition containing a low molecular weight compound having a quinonediazide group is applied onto the primer layer to impregnate the primer layer with the compound having a quinonediazide group. Then, the photosensitive layer composition is applied to form a photosensitive layer.

(3) Including a rubber component in the composition of the primer layer,
Apply the primer layer. Then, a photosensitive layer composition containing a polymer compound having a quinonediazide group and a low molecular weight compound having a quinonediazide group is applied onto the primer layer, and the primer layer is impregnated with the low molecular weight compound having a quinonediazide group.

(4) Including a rubber component in the composition of the primer layer,
Apply the primer layer. Then on the primer layer,
A photosensitive layer composition containing a plurality of types of quinonediazide compounds having different esterification rates of quinonediazide groups is applied, and a quinonediazide compound having one esterification rate is impregnated into a primer layer.

The primer layer in the above methods (2), (3) and (4) preferably contains 30% by weight or more of a rubber component,
As the material of the rubber component, one having an average glass transition point of 0 ° C. or lower is desirable. Examples of the rubber component include the following.

Natural rubber, polybutadiene, styrene-butadiene copolymer, nitrile rubber, acrylic rubber, polyurethane, polyester elastomer, polyamide elastomer, polyetheresteramide elastomer, polyvinyl butyral.

The silicone rubber layer used in the present invention is mainly composed of a silicone rubber obtained by crosslinking an organopolysiloxane having a repeating unit represented by the following formula.

Here, n is an integer of 2 or more, R ¹ and R ² are a hydrogen atom or an unsubstituted or substituted (for example, a halogen atom, a cyano group, an amino group) hydrocarbon group having 1 to 10 carbon atoms, and further as this hydrocarbon group. Desirably, it is an alkyl group, an alkenyl group or a phenyl group, and it is particularly desirable that 60% or more of the total sum of R ¹ and R ² is a methyl group for ease of synthesis. As the constitution of the present invention, the method of crosslinking the organosiloxane to the silicone rubber includes, on average, 1.2 per molecule.
Organopolysiloxane having at least two silanol groups and two or more hydrolyzable groups (eg, acyloxy group, alkoxy group, ketoximate group, amino group, aminooxy group, halogen atom, alkenyloxy group) per silicon atom (more Desirably, three or more) bonded silanes or siloxanes are subjected to a condensation reaction with a crosslinking agent. In this case, it is possible to crosslink by making the number of silanol groups and the number of hydrolyzable groups of the organopolysiloxane substantially the same, or it is possible to crosslink by hydrolytically condensing with the number of hydrolyzable groups in excess. Desirable composition of the silicone rubber before curing is (a) 100 parts by weight of organopolysiloxane having an average of 1.2 or more silanol groups (b) 0.5-20 parts by weight of a crosslinking agent having a hydrolyzable group. Besides, it is also possible to add a coating solvent, a reinforcing filler, a curing catalyst, and a known adhesion-imparting agent.

The thickness of the silicone rubber layer is arbitrary, but if it is too thick, the developability tends to decrease, and if it is too thin, the strength of the plate surface decreases, so that it is 0.25 to 50 μm, more preferably 0.5 to 1 μm.
It is preferably 0 micron. Further, it is optional to provide an adhesive layer between the silicone rubber layer and the photosensitive layer by using, for example, a silane coupling agent or a titanium coupling agent for the purpose of ensuring adhesive strength.

The waterless planographic printing plate precursor according to the present invention is produced, for example, as follows. First, using a conventional coater such as a reverse roll coater, an air knife coater, a Meyerba coater, etc., or a spin coater such as a hoela, a composition for forming a primer layer is coated on a support, dried and required. Accordingly, it is heat-cured to form a primer layer.

On the primer layer, if necessary, a composition for impregnating the quinonediazide group in the primer layer is applied and dried. Then, the photosensitive layer composition for forming the photosensitive layer is applied, dried, and optionally thermally cured to form a photosensitive layer. An adhesive layer is provided on the photosensitive layer, if necessary, and then an uncured composition of silicone rubber is applied and heat-treated for several minutes to provide a silicone rubber layer. Polyester if required,
A protective film of a polymer such as polyolefin is covered on the silicone rubber layer using a laminator or the like.

The printing original plate of the present invention thus produced is exposed through, for example, a vacuum-bonded negative film. The light source used in this exposure step emits a large amount of ultraviolet rays, and a mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a tungsten lamp, a fluorescent lamp or the like can be used.

Then, by using a developing pad containing the plate surface with a developing solution, at least the silicone rubber layer in the exposed area is removed, and a printing plate in which the surface of the photosensitive layer or the primer layer serves as an ink-receptive image area is obtained.

Examples of the developer used in the waterless lithographic printing plate having the characteristics of the present invention include a developer containing a basic substance such as amine and aliphatic hydrocarbons as shown in JP-A-60-28656. A developing solution to which an aromatic hydrocarbon, water, or a halogenated hydrocarbon and the following polar solvent are added is preferable.

Alcohols (methanol, ethanol, etc.) Ethers (dioxane, etc.) Cellosolves (ethyl cellosolve, methyl cellosolve,
Butyl cellosolve, etc.) Carbitols (methyl carbitol, ethyl carbitol, butyl carbitol, etc.) Esters (ethyl acetate, ethyl cellosolve acetate, methyl cellosolve acetate, carbitol acetate).

When the printing plate thus obtained is attached to an offset printing machine and printing is performed without giving dampening water, a printed matter having excellent image reproducibility can be obtained.

〔Example〕

Examples will be shown below. In addition, the weight fraction of the quinonediazide group contained in the primer layer and the photosensitive layer in the original plate is shown in the examples, which is measured by reflection ultraviolet absorption measurement (Hitachi 323
Spectrophotometer), and the effective detection range of the quinonediazide group is 0.
It is at least 01% by weight.

Example 1 A primer composition having the following composition was coated on an aluminum plate and heated at 120 ° C. for 4 minutes to form a primer layer (thickness 1 micron).

(1) Phenol novolac resin with number average degree of polymerization of 5.1
Parts by weight (2) (1) and 1,2-naphthoquinonediazide-5-sulfonic acid chloride esterified product (esterification rate 25%)
10 parts by weight (3) 0.5 parts by weight of dibutyltin diacetate (4) 20 parts by weight of 4,4'-diphenylmethane diisocyanate (5) 990 parts by weight of tetrahydrofuran Then, a photosensitive layer composition having the composition shown below is applied onto the primer layer. After processing, it was heated at 120 ° C. for 1 minute and dried to form a photosensitive layer (thickness: 1.5 g / m ² ).

(1) With a phenol novolac resin having a number average degree of polymerization of 4.6
Esterified product with 1,2-naphthoquinonediazide-5-sulfonic acid chloride (esterification rate 40%) 20 parts by weight (2) Tetrahydrofuran 80 parts by weight Next, an adhesive layer composition having the following composition was formed on the photosensitive layer. It was applied, heated at 100 ° C. for 1 minute and dried to form an adhesive layer. (Thickness 0.5 micron) (1) γ-aminopropyltrimethoxysilane 1 part by weight (2) n-heptane 990 parts by weight Next, a silicone rubber composition having the following composition is coated on the adhesive layer, Heated at 120 ° C, dried and cured (2 micron thickness).

(1) α, ω-dihydroxypolydimethylsiloxane (number average molecular weight 20,000) 100 parts by weight (2) Vinyltris (methylethylketoxime) silane 8 parts by weight (3) Dibutyltin diacetate 0.2 parts by weight (4) n-heptane 800 parts by weight Then, a polypropylene film "Trefan" manufactured by Toray Industries, Inc. having a thickness of 10 microns was laminated as a cover film to prepare a printing original plate.

Peel off the cover film of the obtained printing original plate,
Using a non-woven fabric "Hize Gauze" (manufactured by Asahi Kasei Co., Ltd.) under the immersion of methyl ethyl ketone,
When the adhesive layer and the photosensitive layer were removed and the quinonediazide group contained in the primer layer was measured, it was 2.1% by weight.

This printing plate was vacuum-contacted with a negative film having a dot image of 150 lines / inch through a metal halide lamp (Idlesaki Electric Co., Ltd. Idle Fin 2000 "and irradiated for 60 seconds from a distance of 1 m. When immersed in "Isopar" E (50/50 weight ratio) and lightly rubbed with a development pad, exposed areas are removed for each photosensitive layer, exposing the primer layer, while unexposed areas have a strong silicone rubber layer. Remained, and an image faithfully reproducing the negative film was obtained.

This printing plate was mounted on an offset printing machine (Komori Sprint 2-color machine) and printed using Toyo Ink's "Aqualess" PLT indigo without dampening water. Prints with very good images with 95% reproduction were obtained.

Comparative Example 1 Example 1 except that the primer composition was the following composition
An original plate for printing was obtained in the same manner as.

(1) Phenol novolac resin 100 with number average degree of polymerization of 5.1
Parts by weight (2) Dibutyltin diacetate 0.5 parts by weight (3) 4,4'-Diphenylmethane diisocyanate 20 parts by weight (4) Tetrahydrofuran 900 parts by weight The quinonediazide group contained in the primer layer of the obtained printing plate was used as an example. When measured in the same manner as in No. 1, it was below the effective detection range.

The printing plate precursor was exposed and developed in the same manner as in Example 1 to obtain a printing plate in which the primer layer was exposed in the exposed portion. When printed in the same manner as in Example 1, only 3% to 90% of halftone dots of 150 lines / inch were reproduced, and the reproducibility of shadow portion was poor.

Example 2 A primer composition having the following composition was coated on an aluminum plate, heated at 210 ° C. for 2 minutes and dried to form a primer layer (thickness: 3 μm).

(1) Polyurethane resin (Samprene LQ-T1331, manufactured by Sanyo Kasei Co., Ltd.) 50 parts by weight (2) Blocked isocyanate (Takenate B830, manufactured by Takeda Pharmaceutical Co., Ltd.) 20 parts by weight (3) Epoxy / phenol / urea resin (SJ9372, manufactured by Kansai Paint Co., Ltd.) 8 parts by weight (4) N, N-dimethylformamide 725 parts by weight Next, on the primer layer, the composition shown below was applied so that the film thickness of the solution would be 10 μm. Apply at 100 ℃ for 3
The quinonediazide compound was impregnated into the primer layer by heating for 0 seconds.

(1) Bisphenol and 1,2-naphthoquinonediazide
Esterified product with 5-sulfonic acid chloride (esterification rate: 50%) 1 part by weight (2) Tetrahydrofuran 99 parts by weight Next, a photosensitive layer composition having the following composition was applied to coat 120
It was heated at ℃ for 1 minute and dried to make a photosensitive layer (thickness 1.5g /
m ² ).

(1) Number average molecular weight 11,000 Poly (p-hydroxystyrene) and 1,2-naphthoquinonediazide-5-sulfonic acid chloride ester compound (esterification rate 40%) 10 parts by weight (2) Ethyl cellosolve 90 parts by weight Next Then, an adhesive layer, a silicone rubber layer, and a cover film were provided on the photosensitive layer in the same manner as in Example 1 to obtain a printing original plate.

When the quinonediazide group contained in the primer layer of the obtained printing original plate was measured in the same manner as in Example 1, it was found to be 1.2% by weight.

The obtained printing original plate was exposed to light in the same manner as in Example 1,
Upon development, a printing plate was obtained in which the exposed portion had the primer layer exposed. When this printing plate was printed in the same manner as in Example 1, a printed matter having extremely good image reproducibility in which halftone dots of 150 lines / inch 3 to 95% were reproduced was obtained.

Comparative Example 2 The same primer layer as in Comparative Example 1 was provided on an aluminum plate. Next, in the same manner as in Example 2, the photosensitive layer, the adhesive layer, and the silicone rubber layer were sequentially laminated to obtain a printing original plate.

When the quinonediazide group contained in the primer layer of the obtained printing original plate was measured in the same manner as in Example 1, it was below the effective detection range.

Further, the printing original plate was exposed and developed in the same manner as in Example 1 to obtain a printing plate in which the primer layer was exposed. When printing was performed in the same manner as in Example 1 using the printing plate, 150 lines /
Only 3 to 90% of halftone dots were reproduced, and it was found that the reproducibility of the shadow part was poor.

Example 3 A primer composition having the following composition was applied onto an aluminum plate, heated at 210 ° C. for 2 minutes, dried, and cured to form a primer layer (thickness 7 μm).

(1) Polyester (Byron 300, Toyobo Co., Ltd.)
85 parts by weight (2) Blocked isocyanate (Takenate B830, manufactured by Takeda Yakuhin Co., Ltd.) 15 parts by weight (3) N, N-dimethylformamide 800 parts by weight Next, on the primer layer, the photosensitive layer composition shown below Was applied, heated at 120 ° C. for 1 minute, dried, and cured (thickness 2 μm).

(1) Number average molecular weight 11,000 Poly (p-hydroxystyrene) and 1,2-naphthoquinonediazide-5-sulfonic acid chloride esterified product (esterification rate 25%) 80 parts by weight (2) Number average degree of polymerization of 5.1 With phenol novolac resin
Esterification product with 1,2-naphthoquinonediazide-5-sulfonic acid chloride (esterification rate 25%) 20 parts by weight (3) 4,4'-diphenylmethane diisocyanate 30 parts by weight (4) Dibutyltin diacetate 0.2 parts by weight (5 ) Tetrahydrofuran 500 parts by weight Next, the silicone rubber composition shown below was coated on the photosensitive layer and heated, dried and cured at 120 ° C. for 3.5 minutes to form a silicone rubber layer (thickness 2). micron).

(1) α, ω-dihydroxypolydimethylsiloxane (number average molecular weight 20,000) 100 parts by weight (2) Vinyltris (methylethylketoxime) silane 8 parts by weight (3) Dibutyltin diacetate 0.2 parts by weight (4) γ-aminopropyltrimethoxy 0.5 parts by weight of silane (5) 800 parts by weight of n-heptane A cover film was laminated on the silicone rubber layer in the same manner as in Example 1 to obtain a printing original plate.

The quinonediazide group contained in the photosensitive layer of the obtained printing original plate was 18% by weight, the quinonediazide group contained in the primer layer was 0.5% by weight, and the acetone-soluble component contained in the photosensitive layer was 28% by weight, The acetone-soluble component contained in the primer layer was 16% by weight.

A metal halide lamp (Iwasaki Electric Co., Ltd., Idol Fin 2000) was used for the printing original plate, and a UV meter (Oak Seisakusho Light Measure Type UV-402A) was used.
The entire surface was exposed for 6 seconds with an illuminance of mw / cm ² .

Vacuum contact was made on the printing original plate obtained as described above.
Image exposure was performed for 60 seconds from a distance of 1 m using the above metal halide lamp through a negative film having a halftone image of 150 lines / inch. Then peel off the cover film,
Immerse it in a pretreatment liquid (“Isopar” H / butyl carbitol / ethyl cellosolve / monoethanolamine = 90/10/5 / 0.6 weight ratio), completely wet the exposed plate surface, and treat for 1 minute. Remove the pretreatment liquid on the plate surface with a rubber squeegee,
Next, a developing solution (butyl carbitol / water / 2-ethyl butyric acid / crystal violet = 20/80 /
(2 / 0.2 weight ratio) was poured and the plate surface was lightly rubbed with a developing pad to remove the silicone rubber layer in the imagewise exposed portion and expose the photosensitive layer surface. On the other hand, the silicone rubber layer remained firmly in the part that was exposed only to the entire surface, and an image faithfully reproducing the negative film was obtained.

Using the obtained printing plate, printing was carried out in the same manner as in Example 1 to obtain a printed matter reproducing 3% to 98% of 150 lines / inch.

Comparative Example 3 A primer layer was provided on an aluminum plate as in Comparative Example 1.

Then, on the primer layer, in the same manner as in Example 3, a photosensitive layer,
The silicone rubber layer and the cover film were laminated in this order to obtain a printing original plate.

When the quinonediazide group contained in the primer layer of the obtained printing original plate was measured in the same manner as in Example 1, it was below the effective detection range.

When exposed and developed in the same manner as in Example 3, a printing plate having a photosensitive layer exposed in the exposed portion was obtained. Further, when printed in the same manner as in Example 1, a printed matter that reproduces 3% to 95% of halftone dots of 150 lines / inch was obtained, and it was found that the reproducibility of the shadow portion was poorer than that of Example 3.

Example 4 The primer composition shown on an aluminum plate was applied, and the temperature was 220 ° C.
Was heated, dried and cured for 3 minutes to form a primer layer (thickness: 3 μm).

(1) Polyurethane resin (Impranil ELN, manufactured by Bayer) 100 parts by weight (2) Blocked isocyanate (Takenate B830, manufactured by Takeda Pharmaceutical Co., Ltd.) 20 parts by weight (3) Melamine, urea resin (Super Beckamine OD-L1)
31, manufactured by Dainippon Ink Co., Ltd. 20 parts by weight (4) Titanium oxide paste (Cancoat, manufactured by Kansai Paint Co., Ltd.) 5 parts by weight (5) N, N-dimethylformamide 800 parts by weight On the primer layer, The photosensitive layer composition shown below was applied, and heated, dried, and cured at 120 ° C. for 2 minutes (thickness
1.2 microns).

(1) 90 parts by weight of an esterified product of poly (p-hydroxystyrene) having a number average molecular weight of 8,000 and 1,2-naphthoquinonediazide-5-sulfonic acid chloride (esterification rate 40%) (2) having a number average molecular weight of 8,000 Esterification product of poly (p-hydroxystyrene) and 1,2-naphthoquinonediazide-5-sulfonic acid chloride (esterification rate 10%) 10 parts by weight (3) 4,4'-diphenylmethane diisocyanate 15 parts by weight (4) Dibutyltin diacetate 0.2 parts by weight A silicone rubber layer and a cover film were provided on the photosensitive layer in the same manner as in Example 3 to obtain a printing original plate.

When the quinonediazide group in the primer layer of the obtained printing plate was measured by the same method as in Example 1, it was found to contain 0.2% by weight.

The obtained printing plate was exposed and developed in the same manner as in Example 1 to obtain a printing plate in which the photosensitive layer was exposed in the exposed area. The obtained printing plate was printed in the same manner as in Example 1 to obtain a printed matter reproducing 3% to 96%.

Comparative Example 4 The same primer layer as in Comparative Example 1 was provided on the aluminum plate. Then, on the primer layer, in the same manner as in Example 4,
A photosensitive layer, a silicone rubber layer, and a cover film were laminated in this order to obtain a printing original plate.

When the quinonediazide group in the primer layer of the obtained printing plate was measured by the same method as in Example 1, it was below the effective detection range.

The obtained printing plate was exposed and developed in the same manner as in Example 3 to obtain a printing plate in which the photosensitive layer was exposed in the image-exposed area. When printing was performed in the same manner as in Example 1 using this printing plate, only halftone dots of 3% to 90% of 150 lines / inch were reproduced. That is, it was found that the reproducibility of the shadow portion was poor as compared with Example 4.

Example 5 A primer composition having the following composition was coated on an aluminum plate, heated at 230 ° C. for 2 minutes and dried to form a primer layer. (6 microns thick).

(1) Polyester (Byron 300, Toyobo Co., Ltd.)
75 parts by weight (2) Blocked isocyanate (Desmodur AP staple, manufactured by Sumitomo Bayer Urethane Co., Ltd.) 25 parts by weight (3) N, N-dimethylformamide 800 parts by weight Next, on the primer layer, the following is shown. The photosensitive layer composition was applied, heated at 120 ° C. for 2 minutes and dried to form a photosensitive layer. (Thickness 1.0 g / m ² ) (1) Esterified product of phenol novolac resin having number average degree of polymerization of 5.1 and 1,2-naphthoquinonediazide-5-sulfonic acid chloride (esterification rate 50%) 80 parts by weight ( 2) Esterified product of a phenol novolac oligomer resin having a number average degree of polymerization of 2.3 and 1,2-naphthoquinonediazide-5-sulfonic acid chloride (esterification rate: 50%) 20
Parts by weight (3) 4,4'-diphenylmethane diisocyanate 30 parts by weight (4) dibutyltin diacetate 0.2 parts by weight (5) tetrahydrofuran 500 parts by weight Next, on the photosensitive layer, a silicone rubber layer and a cover were prepared in the same manner as in Example 3. A film was provided to obtain a printing original plate.

When the quinonediazide group contained in the primer layer of the obtained printing original plate was measured in the same manner as in Example 1, it was 0.7% by weight.
Contained.

When the obtained printing plate precursor was exposed and developed in the same manner as in Example 3, a printing plate having a photosensitive layer exposed in the image-exposed area was obtained. When printing was carried out in the same manner as in Example 1 using this printing plate, a printed matter that reproduces halftone dots of 150% / inch from 3% to 98% was obtained.

Example 6 A primer composition having the following composition was coated on an aluminum plate, heated at 130 ° C. for 3 minutes and dried to form a primer layer (thickness: 4 μm).

(1) Butyl acrylate / 2-hydroxyethyl acrylate copolymer (copolymerization ratio 80/20 molar ratio, number average molecular weight 4
4,000) 90 parts by weight (2) 4,4'-diphenylmethane diisocyanate 10 parts by weight (3) Dibutyltin diacetate 0.3 parts by weight Then, on the primer layer, in the same manner as in Example 5, a photosensitive layer, a silicone rubber layer, and a cover film. Was provided to obtain a printing original plate.

When the quinonediazide group contained in the primer layer of the printing original plate was measured by the same method as in Example 1, it was 0.5% by weight.
Met.

When the obtained printing original plate was exposed and developed in the same manner as in Example 3, a printing plate having a photosensitive layer exposed in the image-exposed area was obtained. When printing was performed in the same manner as in Example 1 using this printing plate, a printing plate reproducing halftone dots of 3% to 98% of 150 lines / inch was obtained.

Comparative Example 5 A primer layer was provided on an aluminum plate as in Comparative Example 1.
Next, in the same manner as in Example 5, a photosensitive layer, a silicone rubber layer and a cover film were sequentially provided to obtain a printing original plate.

When the quinonediazide group contained in the primer layer of the printing original plate was measured by the same method as in Example 1, it was below the effective detection range.

When the obtained printing original plate was exposed and developed in the same manner as in Example 3, a printing plate having a photosensitive layer exposed in the image-exposed area was obtained. When printing was performed in the same manner as in Example 1 using this printing plate, only 3% to 92% of halftone dots of 150 lines / inch were reproduced, and the reproducibility of the shadow portion was poor as compared with Example 5. I understood.

〔The invention's effect〕

The feature of the present invention, that is, by containing a quinonediazide group in the primer layer, it is possible to prevent halation of actinic rays transmitted through the photosensitive image forming layer during image exposure, resulting in good reproducibility of halftone dots. Become.

Claims (4)

[Claims] 1. A waterless lithographic printing plate precursor comprising a support, a primer layer, a photosensitive image-forming layer containing a quinonediazide compound, and a silicone rubber layer, which are laminated in this order, and the primer layer contains 0.01 to quinonediazide groups. An original plate for waterless planographic printing characterized by containing 25% by weight. 2. The waterless lithographic printing plate precursor as claimed in claim 1, wherein the primer layer contains a crosslinked polymer. 3. The waterless lithographic printing plate precursor as claimed in claim 1, wherein the quinonediazide group is a naphthoquinonediazide group. 4. The waterless lithographic printing plate precursor as claimed in claim 1, wherein the photosensitive image forming layer has a thickness of 0.3 to 10 g / m ² .