JPH1165098A - Manufacture of photosensitive planographic plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a paleographic plate capable of developing requiring no alkaline developing solution or little alkaline solution, and excellent in printing durability, sensitivity, and image reproducibility. SOLUTION: An oleophilic photo sensitive layer 1A containing a compound containing at least one addition polymerizable ethylenic double bonding and a polymerization initiator are provided on a hydrophilic support body 1 so as to form a photosensitive plate. After the image exposure of the photosensitive planographic plate, the non-image portion of the photosensitive layer 1A is removed from the support body 1 so as to form a photosensitive image. The gummed tape peel strength of the support body is set to be 500 g/cm or less. In image exposure the non-image portion is also exposed by the exposure amount of 1 to 30% of the exposure amount required for photo-curing photosensitive image formation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for making a photosensitive lithographic printing plate. More particularly, the present invention relates to a novel photosensitive lithographic printing plate making method capable of forming a photocurable photosensitive image without requiring a large amount of an alkaline developer.

[0002]

2. Description of the Related Art Conventional photosensitive lithographic printing plates are prepared by forming a negative photosensitive layer such as a diazo resin, a photocrosslinkable polymer, a photopolymerizable composition, or a benzoquinonediazide, A positive-type photosensitive layer such as quinonediazide is applied, and a polyvinyl alcohol layer is formed as an oxygen barrier layer on the photosensitive layer, if necessary.

In order to form a photosensitive image on such a photosensitive lithographic printing plate (plate making), after exposing the printing plate imagewise, an inorganic alkali agent such as sodium silicate or sodium carbonate or diethanolamine, triethanolamine or triethanolamine is used. Using an alkaline developer containing an organic alkali agent such as ethanolamine, immersing the printing plate in this developer and applying a physical stimulus such as a brush to the photosensitive layer in the case of a negative photosensitive layer. The exposed portion is dissolved, and in the case of a positive photosensitive layer, the exposed portion is dissolved and removed to obtain a photosensitive image on the support.

When an ink liquid comprising an emulsion of a lipophilic printing ink and a printing dampening solution is supplied to the surface of the printing plate on which an image has been formed as described above, the exposed surface of the hydrophilic support and the photosensitive image are exposed. The printing ink selectively forms on the photosensitive image and the water selectively adheres on the exposed hydrophilic support surface, thereby forming a printing ink image. A printed matter can be obtained by transferring the printing ink image to an image receiving paper.

The alkali developing solution used in the above plate making process usually requires 10 to 20 L (liter) with respect to an automatic developing apparatus in order to obtain a uniform image. Generally, the same developer is repeatedly used for developing a large number of photosensitive lithographic printing plates in order to reduce the amount of the alkaline developer used. Over time, the repeatedly used alkaline developer is degraded by the photosensitive layer composition dissolved in the solution and oxygen in the air with the elapse of time, and is likely to cause poor development. In order to suppress the deterioration of the alkali developer, a complicated operation for additionally replenishing the alkali developer having a high concentration is required. Even when such a high-concentration alkaline developing solution is replenished, it has been necessary to replace it with a new solution once every several weeks in a normal plate making factory.

When the new solution is replaced, the waste solution of the used alkali developer is discharged. However, in recent years, from the viewpoint of protection of the marine environment, it has become difficult to discard the used alkali developer in the ocean. Disposal of alkaline developers has long been an important issue in the printing arts.

For these reasons, development of a photosensitive lithographic printing plate which does not require development with an alkali developing solution has been promoted. Is insufficient, resulting in poor image quality at the time of printing; lipophilic image area has insufficient durability and long-term printing operation is not possible; or hydrophilic image formation The layers were easily scratched and easily worn away;

To solve such a problem, Japanese Patent Application Laid-Open No. 8-48020 discloses an image forming layer having a lipophilic, radiation-absorbing and heat-sensitive layer formed on a support having a porous hydrophilic surface. A technique for making a lithographic printing plate by the following method using the photosensitive lithographic printing plate described above is described.

(1) The photosensitive lithographic printing plate is imagewise exposed, and heat is generated in the exposed area to enhance the adhesiveness between the image forming layer in the exposed area and the support. The layer is peeled off, exposing the porous hydrophilic surface. (2) In a state in which the transfer sheet having the image forming layer and the printing plate support are in close contact with each other, the image forming layer is irradiated with infrared light to be absorbed and converted into heat, and the image forming layer is transferred from the transfer sheet to the printing plate. Transfer to a support. Alternatively, the imagewise layer of the photosensitive lithographic printing plate provided in advance on the printing plate support is similarly irradiated with light and changed to heat to enhance the adhesion between the image forming layer and the printing plate support, The unexposed portion of the image forming layer is peeled off.

[0010]

SUMMARY OF THE INVENTION A photosensitive lithographic printing plate which enhances the adhesion of the image forming layer provided on the printing plate support to the support by the action of heat by exposure and removes unexposed portions. In the plate making method, when a material having a high thermal conductivity such as aluminum is used as a support of the printing plate, the heat generated by the exposure is efficiently diffused, so that the heat of the unexposed portion and the exposed portion of the image forming layer is used. There is a disadvantage that the difference in the adhesive strength to the support is small, and the sensitivity tends to be insufficient.

Further, in the conventional photosensitive lithographic printing plate, since the hydrophilic support portion is exposed, the transport of the lithographic printing plate,
Or, at the time of mounting on a printing machine, by contacting a conveying roller or a finger on the exposed hydrophilic portion,
The portion is contaminated, and as a result, it is likely to become a stain on an image of a printed matter at the time of printing. For this reason, conventionally, in order to prevent the adhesion of such stains and maintain the hydrophilicity of the non-image area, it is necessary to apply a hydrophilic polymer aqueous solution on a printing plate and dry it to provide a protective layer. It has become.

The present invention solves the above-mentioned conventional problems and does not require an alkali developing solution or can be developed with a small amount of an alkali developing solution and exhibits good sensitivity to ultraviolet to near-infrared light. Another object of the present invention is to provide a plate making method for a photosensitive lithographic printing plate which is excellent in printability such as ink adhesion to print ink and print resistance.

[0013]

According to the present invention, there is provided a method for making a photosensitive lithographic printing plate comprising a compound having at least one addition-polymerizable ethylenic double bond on a hydrophilically treated support, and a photopolymerization method. After imagewise exposing a photosensitive lithographic printing plate provided with a lipophilic photosensitive layer containing an initiation system to photo-curing the photosensitive layer imagewise, the non-image portion of the photosensitive layer is removed from the support. In the method of making a photosensitive lithographic printing plate, which is removed to form a photocurable photosensitive image, the support has a peel strength of the gum tape from the support of 500 g / cm or less determined by a peel strength measurement method using a gum tape. Prior to removing the non-image portion of the photosensitive layer from the support, the non-image portion is exposed to light at a light exposure of 1 to 30 which is necessary for forming a photocurable photosensitive image.
% Exposure.

In the photosensitive lithographic printing plate, the peel strength of the photosensitive layer from the support before exposure, which is determined by a peel strength measuring method using a gum tape, is preferably 0.5 to 200 g / g.
cm, and the peel strength of the photosensitive layer from the support of the photosensitive layer after image exposure is preferably greater than 200 g / cm.

In the following, the exposure amount required for forming a photocurable photosensitive image (hereinafter referred to as "image formation exposure amount").
Exposure performed at an exposure amount of 1 to 30% is sometimes called "weak exposure".

In the present invention, the peel strength (hereinafter, referred to as "gum tape peel strength") of a support subjected to a hydrophilic treatment (hereinafter, referred to as "hydrophilic support") by a gum tape showing surface adhesiveness is shown in FIG. As shown in (a), the surface of the support 1 is covered with an adhesive tape (SLION T manufactured by SLIONTEC).
(APE) 3 was pressed at 25 ° C., 5 kg / cm ² , 50 cm / min, and then the support 1 was fixed on the fixing table 2, and the adhesive tape 3 and the support 1 were rotated in the direction of 180 ° at 30 cm / min. It represents the linear tension (g / cm) obtained by dividing the force F required to pull the adhesive tape 3 away from it by the width of the adhesive tape. Further, as shown in FIG. 1B, the peel strength of the gum tape indicating the adhesion strength of the photosensitive layer to the hydrophilic support is such that the photosensitive layer 1A and the 3 μm-thick polyvinyl alcohol layer 1B are sequentially formed on the surface of the support 1. A laminate is formed, and a gum tape (SLION TAPE manufactured by SLIONTEC) 3 is applied on the surface of the polyvinyl alcohol layer 1B at 25 ° C. and 5 kg / c.
After crimping with m ^2, 50 cm / min, a fixed base support 1 2
And the force F required to pull the gum tape 3 so that the polyvinyl alcohol layer 1B and the photosensitive layer 1A adhered to the gum tape 3 and the support 1 are separated at a distance of 30 cm per minute in the direction of 180 °. Represents the linear tension (g / cm) obtained by dividing by the width of.

In the case of such a photosensitive lithographic printing plate, the non-image of the photosensitive layer is formed by utilizing the adhesiveness of the printing ink or the adhesiveness of the cover sheet, or by a penetrant using a surfactant or the like. The part can be easily removed, and the hydrophilic surface of the support is protected by the non-image part of the photosensitive layer without using an alkali developer or with a small amount of an alkali developer and until printing. Thereby, a clear image can be easily formed. In addition, by exposing the non-image part with a small amount of light and slightly curing the light, the non-image part is removed from the support, so that a part of the non-image part remains on the support. Thus, the non-image portion can be efficiently removed in a sheet shape.

In the present invention, the removal of the non-image portion from the support, that is, the development, is performed as follows.

(1) After exposing the image and non-image portions, the photosensitive lithographic printing plate is mounted on a plate cylinder of a printing press, and a printing ink is supplied onto the photosensitive layer of the photosensitive lithographic printing plate to supply a blanket roller. When the ink is transferred to the surface of the roller, the non-image portion is removed from the support by transferring the non-image portion together with the ink to the roller surface of the blanket roller using the adhesiveness of the ink.
(2) After exposing the image of the non-image portion and the non-image portion, penetrate the photosensitive layer with a penetrant that penetrates the photosensitive layer and reduces the adhesiveness between the photosensitive layer of the non-image portion and the support surface. At the same time, a physical stimulus is applied to remove from the support the non-image portions whose adhesion to the support has been reduced by the penetrant.

(3) After exposing the image and non-image portions, a cover sheet is provided on the photosensitive layer of the photosensitive lithographic printing plate, and when the cover sheet is peeled off from the photosensitive layer, the cover sheet is removed. The non-image portion is removed from the support by transferring the non-image portion to the cover sheet using adhesiveness.

(4) In the above item (3), the cover sheet is peeled off from the photosensitive layer to remove a part of the non-image portion from the support. When the printing ink is supplied onto the photosensitive layer of the photosensitive lithographic printing plate to transfer the ink to the roller surface of the blanket roller, the remaining non-image portion together with the ink is removed by ink. By transferring to the roller surface of the blanket roller using the adhesiveness of
The remainder of the non-image portion is removed from the support.

(5) In the above (3), by removing the cover sheet from the photosensitive layer, a part of the non-image portion is removed from the support, and then the non-image portion penetrates into the photosensitive layer. While penetrating the photosensitive layer with a penetrating agent that reduces the adhesiveness between the photosensitive layer of the non-image portion and the surface of the support,
A physical stimulus is applied to remove from the support the remainder of the non-image areas whose adhesion to the support has been reduced by the penetrant.

[0023]

Embodiments of the present invention will be described below in detail.

The hydrophilic support used in the present invention is in a state (wet state) in which the surface is covered with a thin film of water by fountain solution supplied at the time of printing. The function of preventing the attachment of lipophilic ink particles to form a non-image portion on printed matter, and the non-image portion of the photosensitive layer applied on the hydrophilized surface is easily removed from the hydrophilic support during development. Function.

The hydrophilic support exhibiting such a function has a gum tape peeling strength of 500 g / cm or less when the gum tape is peeled off from the support, which is determined by the above-mentioned method for measuring the gum tape peel strength. is necessary.

Further, the peel strength of the gum tape when the unexposed photosensitive layer is peeled off from the hydrophilic support is 0.5 to 20.
0 g / cm, especially 1-150 g / cm, especially 2-1
00 g / cm, more preferably 10 to 100 g / cm, and the peel strength of the gum tape when peeling the photosensitive layer of the image portion after image exposure is 150 g / cm or more, particularly 200 g / c.
It is preferably larger than m.

More specifically, examples of the hydrophilic support according to the present invention include the following.

Aluminum plate (synthetic paper, coated paper, art) obtained by roughening (graining) the surface of an aluminum plate (hereinafter referred to as “aluminum plate”) by various methods and hydrophilizing by anodic electrolytic treatment or the like. Various paper boards such as paper,
A metal plate such as an aluminum plate, a copper plate, an iron plate, and a stainless steel plate, a wooden plate, a plastic plate such as a polyethylene terephthalate sheet, a polypropylene sheet, a polyethylene sheet, and the like, and a support having excellent dimensional stability are provided with hydrophilicity or water. The graining of the aluminum plate, provided with a swellable hydrophilic polymer layer, improves the adhesiveness of the photosensitive layer formed on the support and improves the water-accepting properties of the non-image areas of the printing plate. Done in This graining affects both the performance and durability of the printing plate, and the quality of the graining is an important factor in determining the overall quality of the printing plate.
By forming fine and uniform grain without pits,
The resulting printing plate will be given essentially good printing performance.

As such a graining method, mechanical and electric graining methods are well known and widely used in the production of lithographic printing plates. Good results can be obtained by using electrolytic graining, referred to as electrochemical graining or electrochemical roughening.

Numerous electrolytic graining methods have already been proposed for the production of lithographic printing plates, for example, US Pat. Nos. 3,755,116, 3,887,447,
Nos. 3,935,080 and 4,087,341
No. 4,201,836, No. 4,272,34
No. 2, No. 4,294,672, No. 4,301,2
No. 29, No. 4,396,468, No. 4,427,
No. 500, No. 4,468,295, No. 4,47
No. 6,006, No. 4,482,434, No. 4,5
No. 45,875, No. 4,548,683, No. 4,
Nos. 564,429, 4,581,996, 4,618,405, 4,735,696, 4,897,168 and 4,919,774. Are listed.

As the anodic electrolysis treatment after graining, an anodic oxidation treatment using an acid such as sulfuric acid or phosphoric acid is performed, and after the anodic oxidation treatment, it is preferable to use thermal silicate (silicone).
) or an electro-silicate treatment is performed.

[0032] In the anodic oxidation treatment, 0.3 g / m ² or more with respect to the surface of the aluminum plate is particularly preferred to form an anodic oxidation film of 0.5 to 10 g / m ^2. This anodized film is porous, and its pore size depends on the anodizing treatment conditions and can take a wide range of values.
0 °, preferably 10 to 500 °.

As a method for hydrophilizing the surface of an aluminum plate by anodizing and silicate treatment, it is already widely known.

For example, US Pat. No. 2,594,289 discloses a patent relating to a method of anodizing a lithographic printing plate.
No. 2,703,781, No. 3,227,63
No. 9, No. 3,511,661, No. 3,804,7
No. 31, No. 3,915, 811 and No. 3,988,
Nos. 217, 4,022,670 and 4,11
Nos. 5,211 and 4,229,266 and 4,
No. 647,346.

As the coating material used in the surface hydrophilization treatment, polyvinyl phosphonic acid, polyacrylic acid, polyacrylamide, zirconate, titanate can be used in addition to the above silicates. Patents relating to the hydrophilization treatment include US Pat. No. 2,714,066.
No. 3,181,461 and No. 3220,832
No. 3,265,504 and No. 3276,868
No. 3,549,365 and No. 4,090,88
No. 4, No. 4,153,461, No. 4,376,9
No. 14, No. 4,383,987, No. 4,399,
No. 021, No. 4,427,765, No. 4,42
No. 7,766, No. 4,448,647, No. 4,4
No. 52,674, No. 4,458,005, No. 4,
Nos. 492,616, 4,578,156, 4,689,272, 4,935,332 and European Patent 190,643.

The thickness of the hydrophilized aluminum plate thus obtained is 0.1 to 1 mm, particularly 0.15 to 1 mm.
It is preferably 0.5 mm, especially 0.15 to 0.4 mm.

When a hydrophilic polymer layer is provided on the above-mentioned various supports, a hydrophilic binder polymer cured with a crosslinking agent or the like, if necessary, is maintained in the hydrophilic polymer layer in order to maintain hydrophilicity. 5 to 100% by weight, preferably 20 to 95% by weight, more preferably 40 to 90% by weight, based on the total solid content of the hydrophilic polymer layer.

Here, the hydrophilic binder polymer is
As a side chain to a polymer composed of carbon-carbon bonds,
A networked polymer containing one or more hydrophilic functional groups such as a carboxyl group, an amino group, a phosphoric acid group, a sulfonic acid group, or a salt, a hydroxyl group, an amide group, and a polyoxyethylene group, or , Carbon atom, carbon-
Any of the carbon bonds is a carboxyl group, an amino group, a phosphoric acid group, a sulfonic acid group, or a carboxyl group, an amino group, a phosphoric acid group, Salt, a hydroxyl group, an amide group, a polymer containing one or more hydrophilic functional groups such as a polyoxyethylene group, specifically,
Poly (meth) acrylate, polyoxyalkylene, polyurethane, epoxy ring-opening addition polymerization, poly (meth) acrylic acid, poly (meth) acrylamide, polyester, polyamide, polyamine, polyvinyl, etc. Polymers such as saccharides and cellulose derivatives are exemplified. Among these, any one of a hydroxyl group, a carboxyl group or an alkali metal salt thereof, an amino group or a hydrogen halide salt thereof, a sulfonic acid group or an amine thereof, an alkali metal salt, an alkaline earth metal salt, and an amide group is added to the segment side chain. Those having a repetition of a kind or a combination of two or more kinds, and those having a polyoxyethylene group overlapped with a part of the hydrophilic functional group and the main chain segment are preferable because of high hydrophilicity. Further, those having a urethane bond or a urea bond in the main chain or side chain of the hydrophilic binder polymer are more preferable because they have high printing durability in a non-image area as well as hydrophilicity.

Hereinafter, the hydrophilic polymer layer containing the hydrophilic binder polymer of the present invention will be described more specifically. In this specification, “(meth) acrylate” indicates “acrylate and / or methacrylate”, and “(meth) acryl” indicates “acryl and / or methacryl”. In addition, the hydrophilic binder polymer according to the present invention may contain various other components described below as necessary.

In order to form a hydrophilic polymer layer containing the hydrophilic binder polymer according to the present invention, for example, first,
(Meth) acrylic acid or its alkali and amine salts,
Itaconic acid or its alkali, amine salt, 2-hydroxyethyl (meth) acrylate, (meth) acrylamide, N-monomethylol (meth) acrylamide,
N-dimethylol (meth) acrylamide, 3-vinylpropionic acid or an alkali or amine salt thereof, vinylsulfonic acid or an alkali or amine salt thereof, 2-sulfoethyl (meth) acrylate, polyoxyethylene glycol mono (meth) acrylate, 2- Hydroxyl group such as acrylamide-2-methylpropanesulfonic acid, acid phosphooxypolyoxyethylene glycol mono (meth) acrylate, allylamine or its halogenated hydrochloride, carboxyl group or its salt, sulfonic acid group or its salt, phosphoric acid or A hydrophilic homo- or copolymer is synthesized using at least one selected from a hydrophilic monomer having a hydrophilic group such as a salt, an amide group, an amino group, and an ether group.

A hydrophilic binder polymer having a functional group such as a hydroxyl group, a carboxyl group, an amino group or a salt thereof, or an epoxy group utilizes these functional groups to add ethylene such as a vinyl group, an allyl group, and a (meth) acryl group. A polymer containing an unsaturated group into which a polymerizable unsaturated group or a ring-forming group such as a cinnamoyl group, a cinnamylidene group, a cyanosinnamylidene group, or a p-phenylenediacrylate group is introduced is obtained. If necessary, a monofunctional or polyfunctional monomer copolymerizable with the unsaturated group, a polymerization initiator described below, and other components described below are added, and the mixture is dissolved in an appropriate solvent to prepare a coating solution. This is applied on a support and subjected to three-dimensional crosslinking after drying or also as drying.

The hydrophilic binder polymer containing an active hydrogen such as a hydroxyl group, an amino group or a carboxyl group may be used together with an isocyanate compound or a blocked polyisocyanate compound and other components described later together with an active hydrogen such as methyl ethyl ketone, propylene glycol monomethyl ether acetate, cyclohexanone, or the like. A coating solution is prepared by adding the solution to a non-containing solvent, and the solution is coated on a support, and dried or three-dimensionally crosslinked after drying.

A monomer having a glycidyl group such as glycidyl (meth) acrylate and a carboxyl group such as (meth) acrylic acid can be used in combination as a copolymer component of the hydrophilic binder polymer. Is a hydrophilic binder polymer having a glycidyl group as a crosslinking agent, α, X-alkane or alkenedicarboxylic acid such as 1,2-ethanedicarboxylic acid or adipic acid, 1,2,3-propanetricarboxylic acid, Polycarboxylic acids such as merit acid, 1,2-ethanediamine, diethylenediamine, diethylenetriamine, polyamine compounds such as α, X-bis- (3-aminopropyl) -polyethylene glycol ether, ethylene glycol, propylene glycol, diethylene glycol, tetraethylene A polyhydroxy compound such as oligoalkylene or polyalkylene glycol such as tylene glycol, trimethylolpropane, glycerin, pentaerythritol and sorbitol can be used, and three-dimensional cross-linking can be carried out using a ring opening reaction with these.

The hydrophilic binder polymer having a carboxyl group or an amino group may be used as a crosslinking agent such as ethylene or propylene glycol diglycidyl ether, polyethylene or polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether,
Three-dimensional crosslinking can be performed using an epoxy ring-opening reaction using a polyepoxy compound such as 1,6-hexanediol diglycidyl ether and trimethylolpropane triglycidyl ether.

Polysaccharides such as cellulose derivatives, polyvinyl alcohol or partially saponified products thereof, glycidol homo- or copolymers, or hydrophilic binder polymers based on these are used for the above-mentioned functional groups capable of undergoing a cross-linking reaction by utilizing the hydroxyl groups contained therein. Groups can be introduced and three-dimensionally cross-linked by the methods described above.

A polyol or polyamine containing a hydroxyl group or an amino group at the polymer terminal, such as polyoxyethylene glycol, and 2,4-tolylene diisocyanate;
Using a polymer in which an ethylene addition polymerizable unsaturated group or a ring-forming group is introduced into a hydrophilic polyurethane precursor synthesized from a polyisocyanate such as 2,6-tolylene diisocyanate, 1,6-hexamethylene diisocyanate, or isophorone diisocyanate. Three-dimensional crosslinking can be performed by the method described above.

Here, when the synthesized hydrophilic polyurethane precursor has an isocyanate group terminal, glycerol mono (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, N -Monomethylol (meth) acrylamide, N-dimethylol (meth) acrylamide,
(Meth) acrylic acid, cinnamic acid, a compound having an active hydrogen such as cinnamic alcohol, and having a hydroxyl group or amino group terminal, (meth) acrylic acid, glycidyl (meth) acrylate, 2-isocyanatoethyl ( (Meth) acrylate and the like.

Further, after applying a polybasic acid and a polyol or a polybasic acid and a polyamine, a three-dimensional crosslinking is carried out by heating, or a water-soluble colloid-forming compound such as casein, glue or gelatin is three-dimensionally crosslinked by heating. A hydrophilic binder polymer having a structure may be formed.

In addition, hydroxyl or amino groups such as homo- or copolymers synthesized from hydroxyl-containing monomers such as 2-hydroxyethyl (meth) acrylate and vinyl alcohol and allylamine, polysaccharides such as partially saponified polyvinyl alcohol and cellulose derivatives, and glycidol homo or copolymers; There is also a method of forming a three-dimensionally crosslinked hydrophilic binder polymer by reacting a group-containing hydrophilic polymer with a polybasic acid anhydride having two or more acid anhydride groups in one molecule.

Here, polybasic acid anhydrides include ethylene glycol bis anhydro trimellitate, glycerol tris anhydro trimellitate,
3,3a, 4,5,9b hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-C] furan-1,3-dione, 3,3 ′,
4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride and the like are exemplified.

An active hydrogen-containing compound such as a polyamine or a polyol having an isocyanate group at the end thereof and an active hydrogen-containing compound such as a polyamine or a polyol are dissolved or dispersed in a solvent and coated on a support to remove the solvent. Can be cured at a temperature at which they do not break down to form a three-dimensional crosslink. In this case, hydrophilicity may be imparted by introducing a hydrophilic functional group into either or both segments and side chains of the polyurethane or the active hydrogen-containing compound. The segment expressing hydrophilicity and the functional group may be appropriately selected from those described above.

Here, the polyisocyanate compounds that can be used include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and 4,4 ′
-Diphenylmethane diisocyanate, 1,5-naphthalenediisocyanate, tolidine diisocyanate,
Examples thereof include 1,6-hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, and bicycloheptane triisocyanate.

In some cases, it is preferable to block (is mask) the isocyanate group by a known method in order to prevent the isocyanate group from changing during handling before and after the coating step. In this case, for example, Keiji Iwata, "Plastic Materials Course Polyurethane Resin"
Sodium acid sulfite, aromatic secondary according to Nikkan Kogyo Shimbun (1974), pp. 51-52, "Polyurethane Resin Handbook" by Keiji Iwata, Nikkan Kogyo Shimbun (1987), pp. 98, 419, 423, 499, etc. Masking agents such as amines, tertiary alcohols, amides, phenols, lactams, heterocyclic compounds, and ketoxime can be used. Of these, isocyanate regeneration temperature is particularly low and hydrophilic is preferable, and examples thereof include sodium acid sulfite.

An addition-polymerizable unsaturated group may be introduced into any of the above-mentioned unblocked or blocked polyisocyanates and used for strengthening crosslinking or reacting with a lipophilic component. The degree of the degree of crosslinking such as the average molecular weight between crosslinks varies depending on the type of the segment used, the type and amount of the associative functional group, and the like, but may be set according to the required printing durability. Normal,
The average molecular weight between crosslinks is set in the range of 500 to 50,000.
If this value is shorter than 500, it tends to be brittle. If it is longer than 50,000, it may be unfavorable because it swells with fountain solution and printing durability is impaired. On the balance between printing durability and hydrophilicity, the average molecular weight between crosslinks is 800 to 30,000, particularly 1000.
About 10,000 is practical.

The hydrophilic binder polymer of the present invention includes:
Further, the following monofunctional monomers and polyfunctional monomers may be used in combination.

That is, Shinzo Yamashita and Tosuke Kaneko, "Crosslinking Agent Handbook", Taiseisha Publishing Co., Ltd. (1981), Kiyomi Kato, "Ultraviolet Curing System", published by Sogo Gijutsu Center (1989), Kiyomi Kato, "UV / EB Curing". Handbook (raw material edition) "Polymer Publishing Association (1985), supervised by Kiyoshi Akamatsu," Practical technology of new photosensitive resin ", CMC, pp. 102-114 (198)
7), N, N'-methylenebisacrylamide, (meth) acryloylmorpholine, vinylpyridine, N-methyl (meth) acrylamide, N, N-
Dimethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminoneopentyl ( Meth) acrylate, N-vinyl-2-pyrrolidone, diacetone acrylamide, N
-Methylol (meth) acrylamide, p-styrene sulfonic acid and its salt, methoxytriethylene glycol (meth) acrylate, methoxy tetraethylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate (number average molecular weight of PEG 4
00), methoxypolyethylene glycol (meth) acrylate (PEG number average molecular weight 1000), butoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, nonylphenoxy Ethyl (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, polyethylene glycol di (meth) acrylate (PEG having a number average molecular weight of 40
0), polyethylene glycol di (meth) acrylate (number average molecular weight of PEG 600), polyethylene glycol di (meth) acrylate (number average molecular weight of PEG 1)
000), polypropylene glycol di (meth) acrylate (number average molecular weight of PEG 400), 2,2-bis [4- (methacryloxyethoxy) phenyl] propane, 2,2-bis [4- (methacryloxy diethoxy) phenyl ] Propane, 2,2-bis [4- (methacryloxypolyethoxy) phenyl] propane or an acrylate thereof, β- (meth) acryloyloxyethyl hydrogendiene phthalate, β- (meth) acryloyloxyethyl hydrogen succinate, polyethylene Or polyphenylene glycol mono (meth) acrylate, 3-chloro-2-hydroxypropyl (meth)
Acrylate, 1,3-butylene glycol di (meth)
Acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropanetri (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, Isobornia (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate,
Stearyl (meth) acrylate, isodecyl (meth)
Acrylate, cyclohexyl (meth) acrylate,
Tetrafurfuryl (meth) acrylate, benzyl (meth) acrylate, mono (2-acryloyloxyethyl) acid phosphate or its methacrylic body, glycerin mono- or di (meth) acrylate, tris (2-
(Acryloxyethyl) isocyanurate or its methacrylic body, N-phenylmaleimide, N- (meth) acryloxysuccinimide, N-vinylcarbazole, divinylethyleneurea, divinylpropyleneurea and the like.

The hydrophilic polymer layer used in the present invention has a particle diameter of 1 to improve the water retention of the dampening solution.
0-40 nm colloidal silica, particle size 10-100 n
m of colloidal alumina, acetic acid, formic acid, citric acid, tartaric acid, malic acid, carboxylic acid such as itaconic acid or a carboxylate alone or a mixture thereof with respect to the total solid content of the hydrophilic polymer layer is 0 to 90% by weight, preferably 0 to 80% by weight can be contained.

Further, in the hydrophilic polymer layer,
For the purpose of improving the coating properties of the photosensitive layer, a suitable surfactant is added to the total solid content of the hydrophilic polymer layer coating solution.
It can be contained at a blending ratio of 0.01 to 10% by weight.

The thickness of the hydrophilic polymer layer used in the present invention is 0.1 to 100 μm, preferably 0.2 to 50 μm.
m, more preferably 0.5 to 20 μm. In addition, the thickness of the various supports forming such a hydrophilic polymer layer is 25 μm to 1 mm, particularly 50 to 500 μm,
In particular, the thickness is preferably 50 to 300 μm.

Next, in the present invention, a compound having at least one addition-polymerizable ethylenic double bond contained in the photosensitive layer formed on the hydrophilic support (hereinafter referred to as "ethylenic compound"). ) Will be described.

The ethylenic compound is a monomer having an ethylenically unsaturated bond such that it undergoes addition polymerization and cures by the action of a photopolymerization initiation system. , Is a concept opposite to the so-called polymer, therefore, in addition to monomers in a narrow sense, dimers,
It also includes trimers and oligomers. ), The photo-curing at the time of exposure into the unevenness or pores on the surface of the hydrophilic support to enhance the adhesiveness between the photosensitive layer and the hydrophilic support and to withstand physical stimulation during development or printing. Provide a photosensitive layer having a film strength, on the other hand, before photo-curing, the adhesion to the hydrophilic support is relatively small,
It becomes the peel strength of the gum tape specified in the present invention, and therefore, in the non-image portion of the photosensitive layer, it is easily formed by the adhesiveness of the printing ink during printing and the adhesiveness of the cover sheet, or by the penetration of a penetrating agent during development. Is required to be able to be removed from the hydrophilic support to expose the hydrophilic surface of the support.

Further, the ethylenic compound has a gum tape peeling strength of 0.5 to 200 g / cm, preferably 1 to 1, when the unexposed photosensitive layer is peeled from the hydrophilic support.
150 g / cm, more preferably 2 to 100 g / cm,
More preferably, when the photosensitive layer adjusted to 10 to 100 g / cm is exposed to light, the peeling strength of the gum tape from the support of the light-cured photosensitive layer in the light-exposed portion is 150 g / cm or more, preferably 200 g / cm. Be larger.

If the unexposed photosensitive layer has a remarkably low peel strength, the photosensitive layer is peeled from the hydrophilic support when the photosensitive lithographic printing plate is handled.
On the other hand, when the temperature is extremely high, a defect during development (remaining film in the non-image portion) occurs.

Furthermore, if the peel strength of the exposed portion of the hydrophilic support is extremely low, the sensitivity is lowered. If the peel strength is extremely low, no photocured image is formed.

Accordingly, for the purpose of satisfying the above-mentioned required characteristics, in the present invention, as the ethylenic compound, an ethylenic compound having a urethane skeleton having the following specific structure, phosphoric acid and a compound containing a (meth) acryloyl group, It is preferable to use one or more of an esterified product of the above or hydroxy (mono / or poly) alkyleneoxy (meth) acrylate (hereinafter, these three types of ethylenic compounds are referred to as “specific ethylenic compounds”). ").)

The ethylenic compound having a urethane skeleton is characterized by having a urethane skeleton in the molecule, and has a function of exhibiting high adhesion to a support and high film strength. Among them, those having a partial structure represented by the following general formula (I) are preferably used.

[0067]

Embedded image

(In the general formula (I), Y ¹ and Y ² each independently represent an acryloyl group or a methacryloyl group. X represents an integer of 0 to 2, y represents an integer of 0 to 3, and z represents an integer of 0 to 3. Represents an integer of 0 to 3, provided that y + zx = 1, and A ³ represents an alkylene group having 1 to ³ carbon atoms or a direct bond.) It has a partial structure represented by the general formula (I). As the compound, a urethane compound obtained by reacting an organic diisocyanate compound or a trimer thereof with a (meth) acryloyl group-containing hydroxy compound is usually used.

Here, examples of the organic diisocyanate compound include aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate, alicyclic diisocyanates such as cyclohexane diisocyanate and isophorone diisocyanate, and aromatic diisocyanates such as tolylene diisocyanate and diphenylmethane diisocyanate. Is mentioned. Also,
Examples of the (meth) acryloyl group-containing hydroxy compound to be reacted with these organic diisocyanate compounds or trimers thereof include those represented by the following general formula (II).

[0070]

Embedded image

(In the formula, x, z, y, and A ³ have the same meanings as those in formula (I).) Examples of such a (meth) acryloyl group-containing hydroxy compound include the following. .

[0072]

Embedded image

Representative urethane compounds obtained by reacting the above-mentioned organic diisocyanate compound or its trimer with a (meth) acryloyl group-containing hydroxy compound are represented by the following general formulas (III) to (VI). Show.

[0074]

Embedded image

[0075]

Embedded image

[0076]

Embedded image

Preferred examples of the ethylenic compound having a urethane skeleton used in the present invention include the following compound E-
1 to E-11.

[0078]

Embedded image

[0079]

Embedded image

[0080]

Embedded image

[0081]

Embedded image

These ethylenic compounds having a urethane skeleton are used singly or as a mixture of two or more, and are usually used in an amount of 10 to 9 relative to the total solid content of the photosensitive layer.
0% by weight, preferably 20 to 70% by weight. If the compounding ratio is less than 10% by weight, the printing durability is reduced. If the compounding ratio is more than 90% by weight, the transferability of the weakly exposed photosensitive layer to a blanket roller or a cover tape is reduced, or the developability with a penetrant. It is liable to lower, which is not preferable in any case.

The phosphoric ester of the (meth) acryloyl group-containing compound among the specific ethylenic compounds is not particularly limited as long as it is an ester of phosphoric acid and the (meth) acryloyl group-containing compound. Are compounds represented by the following general formula (VII). Such a compound is effective in improving the sensitivity and printing durability, and also in enhancing the peelability of a non-image portion during printing.

[0084]

Embedded image

Among the compounds represented by the general formula (VII), those having n of 1 to 10 are particularly preferable in terms of improving the printing durability and the removability of the non-image area. Preferred specific examples of the compound represented by the general formula (VII) include methacryloxyethyl phosphate, bis (methacryloxyethyl) phosphate and the like.

[0086] Such a phosphoric ester compound is as follows.
The seeds are used alone or as a mixture of two or more kinds, and the content is usually 0.1 to 30% by weight, preferably 0.2 to 25% by weight of the total solids of the photosensitive layer. If the proportion is less than 0.1% by weight, the adhesiveness to the support and the developability of the weakly unexposed photosensitive layer are inferior. If the proportion is more than 30% by weight, the sensitivity may be deteriorated.

Further, hydroxy (mono / poly) alkyleneoxy (meth) acrylate as a specific ethylenic compound has a function of enhancing adhesiveness, sensitivity, and developability of a light-exposed photosensitive layer. , The following general formula (V
Those represented by III) are preferred.

[0088]

Embedded image

(In the general formula (VIII), R ⁹ represents a hydrogen atom or a methyl group, A ⁶ represents an optionally branched alkylene group having 1 to 6 carbon atoms which may be substituted by halogen, p represents an integer of 2 or more.) In the general formula (VIII), A ⁶ is preferably an optionally branched alkylene group having 2 to 4 carbon atoms, and the alkylene group may be substituted with halogen. In such a case, the substituent is preferably a chlorine atom. More preferably, A
⁶ is an unsubstituted alkylene group having 2 or 3 carbon atoms which may be branched, that is, polyethylene glycol mono (meth)
Acrylate or polypropylene glycol mono (meth) acrylate is preferred. In general formula (VIII), p is not a problem as long as it is an integer of 2 or more.
It is most preferable that p is from 5 to 50 in terms of adhesion to the support, sensitivity, and developability.

Such hydroxy (mono / poly)
The alkyleneoxy (meth) acrylate is used singly or as a mixture of two or more, and the content thereof is not particularly limited, but is usually 0.1 to 10% based on the total solid content of the photosensitive layer. 30% by weight, preferably 0.2 to
It is 25% by weight, more preferably 0.3 to 20% by weight. When the compounding ratio is less than 0.1% by weight, the adhesiveness to the support and the developability of the weakly exposed photosensitive layer are inferior.
If the amount is more than the percentage by weight, the sensitivity tends to deteriorate.

The phosphoric ester of the (meth) acryloyl group-containing compound and the hydroxy (mono / poly) alkyleneoxy (meth) acrylate compound as the specific ethylenic compound have effective functions. On the other hand, the phosphoric acid ester of a (meth) acryloyl group-containing compound should be applied to a grained grain that has not been subjected to hydrophilization of silicate and an aluminum plate that has only been subjected to anodic oxidation, as a hydrophilic support. Preferably, the hydroxy (mono / poly) alkyloxy (meth) acrylate compound is applied to a grained and anodized aluminum plate that has been subjected to a hydrophilization treatment with silicate as a hydrophilic support.

In the present invention, an ethylenic compound other than the above specific ethylenic compound may be used in combination.
In particular, it is desirable to use a polyfunctional ethylenic compound having two or more ethylenic double bonds together with the above specific ethylenic compound.

Examples of such polyfunctional ethylenic compounds include, for example, an ester of an aliphatic polyhydroxy compound and an unsaturated carboxylic acid, an ester of an aromatic polyhydroxy compound and an unsaturated carboxylic acid, an aliphatic polyhydroxy compound, and an aromatic polyhydroxy compound. And esters obtained by an esterification reaction of a polyvalent hydroxy compound such as an aromatic polyhydroxy compound with an unsaturated carboxylic acid and a polyvalent carboxylic acid.

Here, the ester of the aliphatic polyhydroxy compound and the unsaturated carboxylic acid is not particularly limited, but ethylene glycol diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, Acrylic esters of aliphatic polyhydroxy compounds such as pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, glycerol acrylate, and these exemplified compounds Methacrylates instead of acrylates, and itaconates Instead itaconic acid esters, maleic acid esters, and the like was replaced with crotonic acid ester or maleate was replaced crotonate.

Examples of the ester of the aromatic polyhydroxy compound and the unsaturated carboxylic acid include hydroquinone diacrylate, hydroquinone dimethacrylate, resorcin diacrylate, resorcin dimethacrylate,
Acrylic esters and methacrylic esters of aromatic polyhydroxy compounds such as pyrogallol triacrylate.

The ester obtained by the esterification reaction of the unsaturated carboxylic acid, polycarboxylic acid and polyhydroxy compound is not necessarily a single substance, but typical examples include acrylic acid and phthalic acid. Examples thereof include condensates of acid and ethylene glycol, condensates of acrylic acid, maleic acid and diethylene glycol, condensates of methacrylic acid, terephthalic acid and pentaerythritol, condensates of acrylic acid, adipic acid, butanediol and glycerin.

Other polyfunctional ethylenic compounds used in the present invention include epoxy acrylates such as an addition product of a diepoxy compound and hydroxyethyl acrylate, acrylamides such as ethylenebisacrylamide, and allyls such as diallyl phthalate. Esters and vinyl group-containing compounds such as divinyl phthalate are effective.

Among the ethylenic compounds, polymers having an ethylenic double bond in the main chain include, for example, polyesters obtained by a polycondensation reaction between an unsaturated divalent carboxylic acid and a dihydroxy compound, and unsaturated divalent carboxylic acids. And polyamides obtained by a polycondensation reaction between amides and diamines. Polymers having an ethylenic double bond in the side chain are divalent carboxylic acids having a double bond in the side chain, for example, condensation of itaconic acid, propylidene succinic acid, ethylidene malonic acid and the like with a dihydroxy compound or a diamine compound. There are polymers. Further, a polymer having a functional group having a reactive activity such as a hydroxy group or a methyl halide group in a side chain, for example, polyvinyl alcohol, poly (2-hydroxyethyl methacrylate), polyepichlorohydrin, etc., and acrylic acid, methacrylic acid, crotonic acid A polymer obtained by a polymer reaction with an unsaturated carboxylic acid such as described above can also be suitably used.

The mixing ratio of such an ethylenic compound is from 5 to 98% by weight, especially 20% by weight, based on the total solid content of the photosensitive layer.
It is preferably from 80 to 80% by weight, particularly preferably from 20 to 70% by weight.

Next, the photopolymerization initiation system contained in the photosensitive layer according to the present invention will be described.

As the photopolymerization initiation system, any one can be used as long as it can initiate the polymerization of the above-mentioned ethylenic compound. Among them, particularly those which are sensitive to light in the ultraviolet to near infrared region. Those having properties are preferably used.

In the present invention, examples of the photopolymerization initiation system which absorbs ultraviolet light to generate radicals include dialkyl described in Fine Chemicals, March 1, 1991, Vol 20, No. 4, pages 16 to 26. Acetophenone type, benzyl dialkyl ketal type, benzoin, benzoin alkyl ether type, thioxanthone derivative, acylphosphine oxide type, etc., and JP-A-58-4030.
No. 2, JP-B-45-37377, hexaarylbiimidazoles, s-trihalomethyltriazines, and titanocenes described in JP-A-59-152396 can be used.

Examples of the photopolymerization initiation system sensitive to visible light from ultraviolet to 550 nm include, for example, a system of hexaarylbiimidazole, a radical generator and a dye (Japanese Patent Publication No.
JP-A-37377), a system of hexaarylbiimidazole and (p-dialkylaminobenzylidene) ketone (JP-A-47-2528, JP-A-54-155292).
JP-A-48-15184, a system of a cyclic cis-α-dicarbonyl compound and a dye (JP-A-48-84183), and a system of a substituted triazine and a merocyanine dye (JP-A-54-151024).
JP-A-52-1), a system of ketocoumarin and an activator (JP-A-52-1)
12681, JP-A-58-15503, JP-A-60-15
-88005), a system of a substituted triazine and a sensitizer (JP-A-58-29803, JP-A-58-40302).
JP-A-59-56403), a system of biimidazole, styrene derivative, and thiol (JP-A-59-56403), a sensitizer containing a dialkylaminophenyl group and a biimidazole (JP-A-2-69, JP-A-57-57). 168880, JP-A-5-107761, JP-A-5-210240,
JP-A-4-288818, JP-A-59-140203, JP-A-59-1
No. 89340), titanocene-based systems (Japanese Unexamined Patent Publication No.
No. 152396, JP-A-61-151197, JP-A-63-10602, JP-A-63-41484, JP-A-2-291, JP-A-3-12403, JP-A-3-103
20293, JP-A-3-27393, JP-A-3-5
2050), a system combining a titanocene and a xanthene dye and an addition-polymerizable ethylenically saturated double bond-containing compound having an amino group or a urethane group (JP-A-4-221958, JP-A-4-219756) ) And the like.

Preferable examples of the photopolymerization initiator sensitive to light of ultraviolet to 550 nm include a sensitizing dye having an absorption at a wavelength of 400 to 500 nm, and 2,2′-bis (o-chlorophenyl) -4,4 ′. , 5,5'-Tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,
4 ′, 5,5′-tetra (p-carbethoxyphenyl) biimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (p-bromophenyl) biimidazole Hexaarylbiimidazoles such as 2,2'-bis (o-chlorophenyl) -4,4 ', 5,5'-tetra (o, p-dichlorophenyl) biimidazole, and 2-mercaptobenzthiazole;
A composite photopolymerization initiator comprising an organic thiol compound such as 2-mercaptobenzoxazole or 2-mercaptobenzimidazole, or a sensitizing dye having an absorption at a wavelength of 400 to 500 nm and dicyclopentadienyl-Ti-bis-2, 6-difluoro-3- (pyrrol-1-yl)
-Phenyl-1-yl, dicyclopentadienyl-Ti
-Bis-2,3,5,6-tetrafluorophenyl-1
-Yl, di-cyclopentadienyl-Ti-bis-2,
Titanocene compounds such as 3,4,5,6-pentafluorophenyl-1-yl and the like, and further, a complex photopolymerization initiator comprising a dialkylaminophenyl compound such as ethyl p-diethylaminobenzoate and Michler's ketone are exemplified.

The above dyes for sensitizing hexabiimidazole include, for example, JP-A-2-69, JP-A-57-168088, and JP-A-5-107761.
JP, JP-A 5-210240, JP-A 6-1
Sensitizing dyes described in JP-A-16313 can be mentioned.

Examples of dyes for sensitizing titanocene include, for example, JP-A-6-295061 and JP-A-6-29506.
No. 301208, Japanese Unexamined Patent Publication No. 7-219223,
Sensitizing dyes described in JP-A-7-281434 and JP-A-8-6245 can be exemplified.

The photopolymerization initiation system sensitive to visible to near-infrared light of 550 nm or more includes, for example, a system of a substituted triazine and a squarium salt dye (Japanese Patent Publication No. 8-2073).
No. 4, JP-A-2-306247), a system of a substituted triazine and a cyanine dye (JP-A-2-189548), and a system of an azinium compound and a cyanine dye or a squarium salt dye (JP-A-63-142346). Gazette).

The proportion of such a photopolymerization initiation system is from 0.1 to 50% by weight, especially from 0.2 to 40% by weight, especially from 0.5 to 30% by weight, based on the total solid content of the photosensitive layer. It is preferred that

In the photopolymerization initiation system, a sensitizer is used in an amount of 0.01 to 20.
% By weight, in particular from 0.05 to 10% by weight, and preferably from 0.1 to 80% by weight, in particular from 0.5 to 50% by weight, of the active agent.

In the photosensitive layer according to the present invention, in addition to the ethylenic compound and the photopolymerization initiation system, an organic binder may be further used as a binder for modifying the photosensitive layer and improving physical properties after photocuring. It preferably contains a molecular substance (hereinafter, referred to as “polymer binder”).

In this case, the polymer binder to be used can be selected according to the compatibility, the film-forming property, the adhesion and the purpose of improvement.

As specific examples of the polymer binder, for example,
(Meth) acrylic acid, (meth) acrylic acid ester,
(Meth) acrylamide, maleic acid, (meth) acrylonitrile, styrene, vinyl acetate, vinylidene chloride,
Examples thereof include homo- or copolymers of maleimide and the like, polyethylene oxide, polyvinyl pyrrolidone, polyamide, polyurethane, polyester, polyether, polyethylene terephthalate, acetyl cellulose, and polyvinyl butyral. Among them, a copolymer containing at least one (meth) acrylic acid ester and (meth) acrylic acid as a copolymer component is preferable. The preferred acid value of the polymer binder having a carboxyl group in the molecule is 10 to 250, and the preferred weight average molecular weight (hereinafter abbreviated as “Mw”) is 5,000 to 500,000.

It is desirable that these polymer binders have an unsaturated bond in a side chain, and particularly, those represented by the following general formulas (IXa) to (IXa).
It preferably has at least one type of unsaturated bond represented by Xc).

[0114]

Embedded image

(Wherein, R ¹⁰ represents a hydrogen atom or a methyl group. R ^{11 to} R ¹⁵ each independently represent a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, Having a sulfo group, a nitro group, a cyano group, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, and a substituent An aryloxy group which may be substituted, an alkylamino group which may have a substituent, an arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, or a substituent An arylsulfonyl group optionally having
Represents an oxygen atom, a sulfur atom, an imino group, or an alkylimino group. The substituent such as the alkyl group which may have a substituent is not particularly limited as long as the reactivity of the carbon-carbon double bond is not extremely reduced, but is usually a halogen atom, an alkyl group, a phenyl group. Group, a cyano group, a nitro group, an alkoxy group, an alkylthio group, a dialkylamino group, or the like.

[0116] Of these, those represented by the general formula (IXa), R ¹⁰ is a hydrogen atom or a methyl group, R ¹¹
And R ¹² are more preferably each independently a hydrogen atom, a lower alkyl group, an alkoxy group, a dialkylamino group, or a cyano group, and those represented by the general formula (IXb) include R ¹¹ and R ¹² Are each independently a hydrogen atom, a halogen atom, a lower alkyl group, a carboxyl group, an alkoxycarbonyl group or a cyano group, and R ¹³ is a hydrogen atom, a halogen atom, a lower alkyl group, a carboxyl group, an alkoxycarbonyl group, or a cyano group. It is more preferred that R ¹⁴ and R ¹⁵ are each independently a hydrogen atom, a halogen atom, or a lower alkyl group, and those represented by general formula (IXc) include R ¹¹ , R ¹² and R More preferably, each of ¹³ is independently a hydrogen atom, a halogen atom, a lower alkyl group, a carboxyl group, an alkoxycarbonyl group, or a cyano group. Further, from the easiness of the addition reaction of the carbon-carbon double bond in the general formulas (IXa) to (IXc), the general formula (IX
In a) at least two hydrogen atoms of R ¹⁰ to R ^12, in the general formula (IXb) and (IXc) R ¹¹ ~
Those in which at least two of R ¹³ are hydrogen atoms are particularly preferred.

The methods for synthesizing these compounds are roughly classified into the following two methods.

(Synthesis Method 1) An inert organic solvent solution of a polymer binder having a carboxyl group in the molecule (for example, alcohol, ester, aromatic hydrocarbon, aliphatic hydrocarbon, etc.). A method of reacting an unsaturated compound having an epoxy group with an epoxy group under a reaction condition of about 80 to 120 ° C. for about 1 to 50 hours.

The ratio of the carboxyl group to be reacted with the epoxy group-containing unsaturated compound is not particularly limited as long as the effect of the present invention can be achieved. It is preferably from 20 to 80 mol%, more preferably from 30 to 70 mol%. Within the above range, the developing property is good and the adhesive property is good.

The unsaturated epoxy group-containing compound used in the production of the ethylenic polymer binder having an unsaturated group in the side chain includes:
A compound having at least one addition-polymerizable unsaturated bond and an epoxy group in one molecule.

Examples of the unsaturated compound containing an epoxy group include glycidyl (meth) acrylate, allyl glycidyl ether, α-ethyl glycidyl acrylate, crotonyl glycidyl ether, glycidyl crotonate, glycidyl isocrotonate, monoalkyl itaconate monoglycidyl ester And aliphatic epoxy group-containing unsaturated compounds such as monoalkyl fumarate monoglycidyl ester, monoalkyl maleate monoglycidyl ester, and the following structural formulas (Xa) to (Xn)
And an alicyclic epoxy group-containing unsaturated compound represented by the formula:

[0122]

Embedded image

[0123]

Embedded image

(In each formula, R ¹⁶ , R ¹⁷ and R ¹⁸ each independently represent a hydrogen atom or a methyl group. R ¹⁹ , R ²⁰ and R ²¹ each independently represent a divalent group having 1 to 6 carbon atoms. of .q showing a divalent hydrocarbon group .R ^22, R ²³ is 1 to 10 carbon atoms each independently of an aliphatic saturated hydrocarbon group, r represents an integer of 0.) the epoxy Specific examples of preferred compounds containing a group-containing unsaturated compound include glycidyl methacrylate, allyl glycidyl ether, 3,4-epoxycyclohexylmethyl acrylate, and the like. Among these, particularly preferred compounds are allyl glycidyl ether and 3,4-epoxycyclohexylmethyl acrylate.

(Synthesis Method 2) The above general formulas (IXb) and (IXc)
Copolymerization of an unsaturated carboxylic acid with a compound having at least two types of unsaturated bonds of at least one type of unsaturated bonds having low reactivity and at least one type of unsaturated bonds having higher reactivity as shown in How to combine.

Specific examples of the compound having an unsaturated group represented by the general formula (IXb) include allyl (meth) acrylate, 3-allyloxyethyl (meth) acrylate,
-Allyloxy-2-hydroxypropyl (meth) acrylate, N, N-diallyl (meth) acrylamide,
Cinnamyl (meth) acrylate, crotonyl (meth)
Acrylate, methacryl (meth) acrylate and the like can be mentioned. Of these, allyl (meth) acrylate is particularly preferred.

Specific examples of the compound having an unsaturated group represented by the general formula (IXc) include vinyl (meth) acrylate, vinyl crotonate, 1-propenyl (meth) acrylate, 1-chlorovinyl (meth) acrylate, 2
-Phenyl vinyl (meth) acrylate, vinyl (meth) acrylamide and the like. Of these, vinyl (meth) acrylate is particularly preferred.

By copolymerizing these monomers with an unsaturated carboxylic acid, preferably acrylic acid or methacrylic acid, a copolymer having the unsaturated group is obtained. As the monomer to be copolymerized, another monomer may be copolymerized in addition to the unsaturated carboxylic acid, and examples thereof include alkyl acrylate, alkyl methacrylate, acrylonitrile, and styrene. The proportion of the compound having the structure of the general formulas (IXb) and (IXc) to be copolymerized with respect to the total components of the polymer is preferably 10 to 90 mol%, more preferably 30 to 80 mol%.
Mol%. If it is less than this range, the sensitivity and printing durability are poor, and if it is too large, the image reproducibility deteriorates.

The compounding ratio of such a polymer binder is from 0 to 90% by weight, especially from 20 to 90% by weight, based on the total solid content of the photosensitive layer.
It is preferably 80% by weight, particularly preferably 30 to 70% by weight.

In order to form a photosensitive layer according to the present invention using the above-mentioned ethylenic compound, photopolymerization initiator and polymer binder, a photopolymerizable composition obtained by mixing these materials is used without solvent. To form a photosensitive layer, or by dissolving in a suitable solvent and applying as a solution to the hydrophilic support, followed by drying to form a photosensitive layer. When using a solvent,
Examples of the solvent include methyl ethyl ketone, cyclohexanone, butyl acetate, amyl acetate, ethyl propionate, toluene, xylene, monochlorobenzene, carbon tetrachloride, trichloroethylene, trichloroethane, dimethylformamide, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, benzoquinone, and propylene glycol monomethyl. Ether, N-methylpyrrolidone, and the like can be used, and these can be used alone or in combination of two or more.

The photopolymerizable composition for forming the photosensitive layer may further contain, if necessary, other additives such as hydroquinone, p-methoxyphenol, 2,6-di-t-butyl-p- Thermal polymerization inhibitors such as cresol, coloring agents composed of organic or inorganic dyes and pigments, dioctyl phthalate, didodecyl phthalate, plasticizers such as tricresyl phosphate, sensitivity characteristics improvers such as tertiary amines and thiols,
Other additives such as a dye precursor may be added.

In this case, the preferable compounding amount of these various additives is such that the thermal polymerization inhibitor 2 based on the total solid content of the photosensitive layer.
% By weight, colorants such as dyes and pigments, 40% by weight or less, plasticizers, 10% by weight or less, sensitivity characteristic improvers, 20% by weight or less,
The content of the dye precursor is 30% by weight or less.

As a method for applying the photopolymerizable composition to the hydrophilic support, known methods such as dip coating, coating rod, spinner coating, splat coating, and roll coating can be employed. The drying temperature after application is usually about 50 to 150 ° C. for about 0.5 to 10 minutes.

The photosensitive layer formed as described above is
It has no tackiness at room temperature (25 ° C.) and is treated as a one-layer type photosensitive lithographic printing plate having only a photosensitive layer coated on a hydrophilic support without providing a protective layer on the photosensitive layer. It is preferable that it can be.

However, on the photosensitive layer, the non-image portion of the photosensitive layer which has been subjected to the weak exposure is used for the purpose of preventing the polymerization inhibiting action by oxygen, or the adhesiveness of the printing ink is used in the printing step. Alternatively, as a pre-treatment for removing by a penetrant and a physical stimulus, a cover sheet can be provided by lamination or coating for the purpose of peeling and removing the non-image portion.

Among the cover sheets, examples of the coating type oxygen blocking layer include water-soluble materials such as polyvinyl alcohol, polyvinylpyrrolidone, gelatin, polyethylene oxide, cellulose, water-soluble modified nylon, polyacrylic acid, polyacrylonitrile, and starch. Polymers, especially those made of polyvinyl alcohol, are excellent. Since the oxygen blocking effect appears when the coating film thickness is 0.1 μm or more, it is usually 0.2 to 10 μm, preferably 0.5 to 5 μm.
m, more preferably 0.5 to 4 μm. This thin film is peeled and removed together with the photosensitive layer in the non-image portion by a printing ink in a printing step after exposure. Alternatively, when the photosensitive layer in the non-image portion is peeled and removed by physical stimulation, the photosensitive layer is peeled and removed together with the photosensitive layer in the non-image portion.

On the other hand, by peeling off the cover sheet, the adhesiveness between the cover sheet and the photosensitive layer is utilized.
As a cover sheet having a function of peeling and removing only the non-image portion of the photosensitive layer from the support, those having a film thickness increased to withstand the physical force applied at the time of peeling the coated oxygen barrier layer, Specifically, a film having a thickness of 1 to 100 μm, preferably 2 to 50 μm, more preferably 3 to 30 μm is preferable.

When the cover sheet is provided by lamination, the cover sheet is laminated on the photosensitive layer under such a temperature condition that the photosensitive layer exhibits tackiness, and the cover sheet is separated from the photosensitive layer at room temperature. Some peel off.

In this case, as a material of the cover sheet,
Polyesters such as polyethylene terephthalate, polypropylene, polyolefins such as polyethylene, cellophane, celluloid, various plastic sheets such as polyvinyl alcohol, paper, cloth, wood board, aluminum, metal plates such as copper and the like can be mentioned. Is usually 5
It is 300 μm, preferably 5 to 150 μm, more preferably 10 to 100 μm.

Of these, a transparent cover sheet can be used after laminating the photosensitive layer before or after image exposure, while an opaque cover sheet can be laminated after image exposure. It is limited to the method of doing.

In general, the cover sheet for lamination preferably has an appropriate oxygen blocking effect.

Further, when the cover sheet is provided on the photosensitive layer by lamination, an adhesive layer for enhancing the adhesiveness between the cover sheet and the photosensitive layer is applied on the photosensitive layer or the cover sheet in advance, and then the laminate is laminated. You can also. In this case, it is possible to perform lamination without using the adhesiveness of the photosensitive layer, and therefore, by lowering the lamination temperature.
In this case, it is preferable to provide the adhesive layer on the photosensitive layer because the adhesive layer material enters the unevenness on the surface of the photosensitive layer and the anchor effect is generated, so that the weakly exposed photosensitive layer can be effectively removed.

Examples of the material used for forming the adhesive layer include:
Examples include thermosetting urethane-based adhesives, epoxy-based adhesives, emulsion-type adhesives having a low softening point such as polyvinyl acetate, and uncured room-temperature adhesives. Is usually 0.1 to 100 μm, preferably 0.3 to 50 μm, more preferably 0.5 to 30 μm.
It is formed to a thickness of μm.

The above-mentioned coating type cover sheet and laminate type cover sheet may be used in combination in order to combine their functions and features.

When the light-exposed portion of the photosensitive layer is peeled off by the cover sheet, only a part of the light-exposed weakly exposed portion is peeled off, and the photosensitive layer is removed from the support so that the remainder remains on the support. Is preferably removed. As a result, the remaining photosensitive layer has an effect of protecting the hydrophilic surface of the support, and it is possible to prevent adhesion of dirt due to contact with a transport roller or a finger during transport of the sample. In addition, since the residual film of the photosensitive layer left on the support is thin, oxygen is easily transmitted, and the photosensitivity of the residual film is significantly reduced. This also has the effect of making it possible.

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

In the present invention, a silver salt mask film for printing plate making is brought into close contact with the photosensitive layer, and then the photosensitive lithographic printing plate is brought into close contact exposure through the mask film, or a light source is used without using a mask film. Image exposure is performed by a method of scanning and exposing a light beam spot obtained by condensing the above light beams, and the exposed portions of the photosensitive layer are photo-cured.

The exposure light source is not particularly restricted but includes, for example, carbon arc, high pressure mercury lamp, xenon lamp,
A metal halide lamp, a fluorescent lamp, a tungsten lamp, a halogen lamp, a helium cadmium laser, an argon ion laser, a YAG laser, a helium neon laser, a visible to near-infrared semiconductor laser, and the like can be particularly preferably used.

In the present invention, the non-image portion is slightly exposed to light and slightly light-cured to such an extent that the adhesiveness between the photosensitive layer and the support in the non-image portion is not improved. Thereby, when the non-image portion is removed from the support, the photosensitive layer of the non-image portion is easily removed in a sheet shape, and it is possible to prevent a part of the non-image portion from remaining excessively on the support. it can. The exposure amount at the time of weak exposure of the non-image portion is 1 to 30%, preferably 2 to 20% of the image formation exposure amount. If the amount of weak exposure is less than this range, the effect of performing weak exposure is not obtained, and if it is too large, the photocuring of the non-image portion is too fast, and the non-image portion adheres firmly to the support and peels off. It is difficult to remove.

The light exposure of the non-image portion can be performed before or after the image exposure or at the same time as the image exposure. The light source for the weak exposure is appropriately selected from the light sources for the image exposure described above. be able to.

The imagewise exposed and weakly exposed photosensitive lithographic printing plate can be used as it is on a plate cylinder of a printing press and used for printing. Immediately after printing is started, the printing ink becomes hydrophilic due to the tackiness of the printing ink. The unexposed portion of the photosensitive layer having low adhesion to the support is peeled off and transferred to the roller surface side of the blanket rubber roller (impression cylinder) together with the printing ink. The photosensitive layer transferred to the blanket rubber roller is transferred to printing paper together with the ink, and the printing paper in the initial stage of printing becomes waste paper, thereby achieving print development. As a result, the hydrophilic surface of the support in the portion is exposed, and an image-like ink image composed of the printing ink water and the ink balance is formed on the plate surface. The ink image is transferred to a blanket roller and then to printing paper, and printing is performed.

As another plate-making method, a penetrating agent is applied on a photosensitive lithographic printing plate which has been image-exposed and weakly exposed, and the penetrating agent is penetrated into the unexposed photosensitive layer, so that the unexposed photosensitive layer becomes hydrophilic. While significantly reducing the adhesiveness with the support, the cloth,
There is a method in which a photosensitive layer in a non-image portion is peeled off by applying a physical stimulus such as cotton, sponge, brush, or spray.

In this case, in the present invention, the peel strength of the gum tape of the hydrophilic support is 500 g / cm or less, and the peel strength of the gum tape of the unexposed photosensitive layer and the support is preferably 0.5 g / cm or less.
As soon as the penetrant penetrates the photosensitive layer and reaches the interface between the photosensitive layer and the hydrophilic support, the weakly exposed photosensitive layer becomes hydrophilic. A low state of adhesion to the support is reached that can be easily removed from the body in a short time. Therefore, if there is a small amount of penetrant solution so that the penetrant can penetrate the photosensitive layer sufficiently,
The above-described development processing can be performed.

On the other hand, the conventional photosensitive lithographic printing plate for alkali developing treatment has a relatively high adhesiveness between the unexposed photosensitive layer and the support, and has a gum tape peel strength of 200 g.
/ Cm, it is necessary to swell and dissolve the photosensitive layer with a large amount of alkali developing solution and to dissolve it in a large amount of alkali developing solution without utilizing the change in the adhesion between the photosensitive layer and the support. . For this reason, in the conventional alkali developing treatment, a large amount of an alkali developing solution and a long swelling, dissolving, and eluting time are required.

The penetrating agent used in the present invention has a function of permeating the weakly exposed photosensitive layer according to the present invention to reduce the adhesiveness between the weakly exposed photosensitive layer and the support. Examples of the penetrant exhibiting such a function include an aqueous solution or an organic solution containing a surfactant, an organic solvent, an alkali agent, and the like.

Surfactants suitable as penetrants include:
Nonionic surfactants such as polyoxyethylene alkylene ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, monoglyceride alkyl esters; alkylbenzene sulfonates, alkylnaphthalene sulfonates, Anionic surfactants such as alkyl sulfates, alkyl sulfonates and sulfosuccinate salts; and amphoteric surfactants such as alkyl betaines and amino acids.

Suitable alkaline agents include sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, sodium carbonate, potassium carbonate, and bicarbonate. Inorganic alkaline agents such as sodium, and organic amine compounds such as trimethylamine, diethylamine, isopropylamine, n-butylamine, monoethanolamine, diethanolamine, and triethanolamine, and the like.Examples of the organic solvent include isopropyl alcohol, Examples include benzyl alcohol, ethyl cellosolve, butyl cellosolve, phenyl cellosolve, propylene glycol, diacetone alcohol and the like.

The above-mentioned surfactants, organic solvents and alkaline agents can be used alone or in combination of two or more. However, in recent years, there has been an increase in awareness of the problem of disposal of alkaline agents, and in view of odor and working environment. Therefore, a penetrant using a surfactant is preferable.

Preferred penetrants are surfactants: 0.05 to 70% by weight, especially 0.1 to 40% by weight.
% By weight Organic solvent: 0.05 to 70% by weight, especially 0.1 to 40% by weight Alkaline agent: 0.05 to 10% by weight, especially 0.1 to 5% by weight aqueous solution containing one or more kinds Or an organic solution.

Specifically, this developing treatment is performed by wiping the photosensitive layer after image exposure and light exposure using a cloth, cotton, sponge, or the like impregnated with the above-described penetrant. The method can be carried out by permeating a penetrating agent to significantly lower the adhesiveness of the non-image portion of the weakly exposed photosensitive layer to the support, and by peeling off the weakly exposed photosensitive layer by applying a physical stimulus.

The photosensitive lithographic printing plate on which an image has been formed by the above-described penetrating development can be used for printing as it is. However, in order to remove a penetrant remaining on the photosensitive layer, cloth, cotton,
It is preferable to wipe it off using a sponge or the like, or to perform a water washing treatment.

In addition, the photosensitivity of the non-image portion of the exposed photosensitive lithographic printing plate is remarkably reduced, the handling environment of the exposed photosensitive lithographic printing plate is made brighter, and the photosensitive material removed from the support during printing is used. The non-image portion of the non-conductive layer is mixed with fountain solution as dust, or adheres to the surface of the blanket rubber roller to prevent problems such as lowering the ink transferability of the blanket roller, or during penetration development, In order to reduce the amount of the weakly exposed photosensitive layer to be removed from the support and reduce the development time, the non-image portion of the photosensitive layer of the image-exposed photosensitive lithographic plate is subjected to an on-press printing process or a penetrating development process. It can also be peeled off.

In this case, as a method of peeling and removing a part or the whole of the non-image portion of the photosensitive layer, a cover sheet as described above is provided, and the photosensitive layer is peeled off so that the photosensitive layer is removed on the cover sheet side. A method of removing and transferring and removing only the non-image portion is preferable. Further, at this time, the non-image portion of the photosensitive layer is completely removed from the hydrophilic layer of the support. It is preferable to remove and remove so as to remain on the surface.

The cover sheet may be peeled off at room temperature, but if necessary, it may be peeled off at a temperature of 30 to 120 ° C. to facilitate the transfer of the non-image portion. .

[0165]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof. In the following, “%” indicates “% by weight” unless otherwise specified.

The following Examples and Comparative Examples used:
The hydrophilic support, the ethylenic compound and the polymer binder are as follows.

An aluminum plate having a hydrophilic support thickness of 0.2 mm was degreased with 3% sodium hydroxide, and was degreased in a 18.0 g / L nitric acid bath at 25 ° C. and 80 ° C.
Electrolytic etching was performed at a current density of A / dm ² for 15 seconds, followed by desmutting with a 1% aqueous sodium hydroxide solution at 50 ° C. for 5 seconds, and then neutralizing with a 10% aqueous nitric acid solution at 25 ° C. for 5 seconds. After washing in a 30% sulfuric acid bath, 30 ° C, 10A / d
Anodizing was performed for 16 seconds under the conditions of m ² , washed with water and dried to obtain an aluminum plate for a lithographic printing plate. The formed anodized film is 2.1 g / m ² .

Ethylenic compound-1 "PM-2" manufactured by Nippon Kayaku Co., Ltd. (structural formula is as follows) Ethylenic compound-2 "UA-306H" manufactured by Shin-Nakamura Chemical Co., Ltd. (structure The formula is as follows.) Ethylene compound-3 "ABPE-4" manufactured by Shin-Nakamura Chemical Co., Ltd. (The structural formula is as follows.)

[0169]

Embedded image

Polymer binder methyl methacrylate / isobutyl methacrylate / isobutyl acrylate / methacrylic acid = 35/20/1
0/35 mol% (preparation ratio) of copolymer (Mw 70,000) 2
00 parts by weight, the following alicyclic epoxy-containing unsaturated compound 75
Parts by weight, 2.5 parts by weight of p-methoxyphenol, 8 parts by weight of tetrabutylammonium chloride and 800 parts by weight of cyclohexanone were added to a reaction vessel.
Unsaturated groups reacted with 60% of the methacrylic acid component of the copolymer used as the ethylenic polymer molecule binder (Mw 75,000, acid value 60) obtained by stirring reaction in air for hours. 25% solution.

[0171]

Embedded image

Examples 1 and Comparative Example 1 A coating solution of the photopolymerizable composition having the following composition was prepared, and this coating solution was applied to a support using a bar coater so as to have a dry film thickness of 2 g / m ^2. And dried. Further, an aqueous solution of polyvinyl alcohol was applied and dried using a bar coater to a thickness of 3 μm at a dry film weight of 3 g / m ² to prepare a photosensitive lithographic printing plate. The following items were evaluated for the obtained photosensitive lithographic printing plate, and the results are shown in Table 1.

Photopolymerizable composition coating solution blending (parts by weight) Ethylenic monomer: 55 (Ethylene compound-1: 5, Ethylene compound-2: 25, Ethylene compound-3: 25) Polymer Binder: 45 (solid content) Compound of the following structural formula (A-1): 2.0 Titanocene compound of the following structural formula (B-1): 10 2-mercaptobenzothiazole: 5.0 N, N-dimethylbenzoic acid Acid ethyl ester: 10 Copper phthalocyanine pigment: 3.0 Cyclohexanone: 1090

[0174]

Embedded image

Evaluation Items <Peel Strength> The peel strength of the gum tape of the unexposed photosensitive layer, the exposed (photocured) photosensitive layer, and the hydrophilic support was measured in accordance with the above-described measuring method (shown in FIG. 1). The peel strength of the gum tape of the support is the peel strength when peeling the gum tape adhered to the support on which the photosensitive layer is not formed.

<Sensitivity> A diffraction spectroscopic irradiation apparatus (“RM-2 manufactured by Narumi”) for irradiating the photosensitive lithographic printing plate with light so that the irradiation light wavelength decreases in the horizontal direction and the light intensity decreases logarithmically in the vertical direction.
3)), and a gum tape ("SLIONTA" manufactured by SLIONTEC) on the polyvinyl alcohol layer.
PE "), and then the gum tape was peeled from the sample and most of the non-image portions of the photosensitive layer of the sample were peeled away from the support. Subsequently, the sample was mounted on a plate cylinder on a printing machine (lithographic printing machine “Diamond F-2” manufactured by Mitsubishi Heavy Industries, Ltd.), and 100 sheets were printed to perform print development. The light energy required for photocuring with a light beam of 488 nm was determined from the height of the printed image on the 100th printed material obtained in the vertical direction.

<Ink Image Formability> The photosensitive lithographic printing plate was scanned with an air-cooled argon laser ("PI-R" manufactured by Dainippon Screen Co., Ltd.) at the exposure required for photocuring determined by the above sensitivity measurement. Then, the non-image portion was lightly exposed at an exposure amount of 10% of the image forming exposure amount, and print development was performed in the same manner as in the evaluation of sensitivity. Evaluation of ink image formability was carried out based on the number of pieces of paper until a complete ink image was obtained for the first time in the print development (Example 1). As a comparison, evaluation was performed in exactly the same manner except that weak exposure was not performed (Comparative Example 1).

Example 2 and Comparative Example 2 In Example 1 and Comparative Example 1, except that the non-image portion was not removed from the support before the print development in the evaluation of the sensitivity and the ink image forming property. Evaluation was performed in the same manner, and the results are shown in Table 1.

[0179]

[Table 1]

Example 3 In Example 1, a gum tape similar to that for sensitivity evaluation was applied on the polyvinyl alcohol layer of a sample that had been subjected to laser image exposure and weak exposure in the same manner as in the method for evaluation of ink image formability. After peeling off the gum tape from the sample and removing most of the non-image portion of the photosensitive layer of the sample from the support, the photosensitive layer image surface of the sample is penetrated with a penetrant (sodium alkylnaphthalenesulfonate type surfactant ( After reciprocating once every two seconds using Wes (old cloth) impregnated with a 30% by weight aqueous solution of Kao Corporation "Perex NBL"), the remaining film of the non-image portion of the photosensitive layer was 4%.
It was completely removed in seconds, forming a photocured image.

Comparative Example 3 A plate was made in exactly the same manner as in Example 3 except that weak exposure was not performed, and a rubbing treatment was similarly performed using a waste cloth (used cloth) impregnated with a penetrant. However, it took 10 seconds for the non-image portion to be completely removed.

[0182]

As described in detail above, according to the present invention, a photosensitive lithographic printing plate having excellent printing durability, sensitivity and image reproducibility can be produced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a method for measuring a peel strength of a gum tape.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support 1A Photosensitive layer 1B Polyvinyl alcohol layer 2 Fixed base 3 Gum tape

Claims (8)

[Claims] 1. Photosensitivity obtained by providing a lipophilic photosensitive layer containing a compound having at least one addition-polymerizable ethylenic double bond and a photopolymerization initiation system on a support subjected to a hydrophilic treatment. After imagewise exposing the lithographic printing plate to photocure the photosensitive layer imagewise, a non-image portion of the photosensitive layer is removed from the support to form a photocurable photosensitive image of the lithographic printing plate. In the plate-making method, the support has a peel strength of the gum tape from the support of 500 g / cm determined by a peel strength measurement method using a gum tape.
Before removing the non-image portion of the photosensitive layer from the support, exposing the non-image portion with an exposure amount of 1 to 30% of an exposure amount required for forming a photocurable photosensitive image. A plate making method for a photosensitive lithographic printing plate, which is a feature. 2. The photosensitive material according to claim 1, wherein the peel strength of the photosensitive layer from the support before exposure is 0.5 to 200 g / cm, which is determined by a peel strength measuring method using a gum tape. Lithographic printing plate. 3. The method according to claim 1, wherein the peel strength of the image layer after image exposure from the support of the photosensitive layer is greater than 200 g / cm, determined by the peel strength measuring method using a gum tape. Photosensitive lithographic printing plate. 4. The photosensitive lithographic printing plate according to claim 1, wherein after the image and non-image portions are exposed, a photosensitive lithographic printing plate is mounted on a plate cylinder of a printing press. When supplying the printing ink on the layer and transferring the ink to the roller surface of the blanket roller, by transferring the non-image portion together with the ink to the roller surface of the blanket roller using the adhesiveness of the ink, A method of making a photosensitive lithographic printing plate comprising removing a non-image portion from a support. 5. The method according to claim 1, wherein after exposure of the image and the non-image portion, the photosensitive layer of the non-image portion penetrates into the photosensitive layer of the non-image portion and the surface of the support. A photosensitive agent, wherein a non-image portion having reduced adhesion to a support is removed from a support by applying a physical stimulus to the photosensitive layer while penetrating a penetrating agent for reducing the adhesiveness into the photosensitive layer. A plate making method for a lithographic printing plate. 6. The image and non-image part according to claim 1, wherein a cover sheet is provided on the photosensitive layer of the photosensitive lithographic printing plate before or after exposure of the image and non-image part. When peeling the cover sheet from the photosensitive layer after the exposure of, by transferring the non-image portion to the cover sheet side using the adhesiveness of the cover sheet,
A method of making a photosensitive lithographic printing plate, comprising removing the non-image portion from a support. 7. The photosensitive lithographic printing plate according to claim 6, wherein the cover sheet is peeled off from a photosensitive layer to remove a part of the non-image portion from a support. When the printing ink is supplied onto the photosensitive layer of the photosensitive lithographic printing plate to transfer the ink to the roller surface of the blanket roller, the remaining non-image portion together with the ink is adhered to the ink. A method for making a photosensitive lithographic printing plate, wherein the remaining non-image portion is removed from a support by transferring to a roller surface of a blanket roller by utilizing the property. 8. The non-image portion according to claim 6, wherein the cover sheet is separated from the photosensitive layer to remove a part of the non-image portion from the support, and then to penetrate the non-image portion of the photosensitive layer. While penetrating the photosensitive layer with a penetrating agent that reduces the adhesiveness between the photosensitive layer and the support surface of the non-image portion,
A method for making a photosensitive lithographic printing plate, comprising applying a physical stimulus to remove from the support the remaining non-image portion having reduced adhesion to the support due to the penetrant.