LITHOGRAPHIC PRINTING PLATE PRECURSOR, METHOD OF PREPARING LITHOGRAPHIC PRINTING PLATE, AND LITHOGRAPHIC PRINTING METHOD

Abstract

Provided are a lithographic printing plate precursor including a support, and an image recording layer on the support, in which the image recording layer contains organic particles containing an addition polymerization type resin that has a constitutional unit A having a hydrogen bond-donating site, and a content of the constitutional unit A in the addition polymerization type resin is greater than 20% by mass with respect to a total mass of the addition polymerization type resin; and a method of preparing a lithographic printing plate using the lithographic printing plate precursor.

Claims

1. A lithographic printing plate precursor comprising: a support; and an image recording layer on the support, wherein the image recording layer contains organic particles containing an addition polymerization type resin that has a constitutional unit A having a hydrogen bond-donating site, and a content of the constitutional unit A in the addition polymerization type resin is greater than 20% by mass with respect to a total mass of the addition polymerization type resin.

2. The lithographic printing plate precursor according to claim 1, wherein the content of the constitutional unit A in the addition polymerization type resin is 25% by mass or greater with respect to the total mass of the addition polymerization type resin.

3. The lithographic printing plate precursor according to claim 1, wherein the addition polymerization type resin further has a constitutional unit having an aromatic ring.

4. The lithographic printing plate precursor according to claim 1, wherein the addition polymerization type resin further has the constitutional unit containing a hydrophilic group.

5. The lithographic printing plate precursor according to claim 4, wherein the hydrophilic group is an ionic group or a group having a polyalkylene oxide structure.

6. The lithographic printing plate precursor according to claim 4, wherein the hydrophilic group is a group represented by Formula Z,
-Q-W-Y  Formula Z in Formula Z, Q represents a divalent linking group, W represents a divalent group having a hydrophilic structure or a divalent group having a hydrophobic structure, and Y represents a monovalent group having a hydrophilic structure or a monovalent group having a hydrophobic structure, where any of W and Y has a hydrophilic structure.

7. The lithographic printing plate precursor according to claim 4, wherein the hydrophilic group is a group having a polyalkylene oxide structure.

8. The lithographic printing plate precursor according to claim 4, wherein the hydrophilic group is a sulfonate group or a sulfonic acid group.

9. The lithographic printing plate precursor according to claim 4, wherein a content of the constitutional unit containing the hydrophilic group in the addition polymerization type resin is in a range of 1% by mass to 20% by mass with respect to the total mass of the addition polymerization type resin.

10. The lithographic printing plate precursor according to claim 1, wherein the organic particles include organic particles containing an ethylenically unsaturated group on each surface thereof.

11. The lithographic printing plate precursor according to claim 1, wherein the image recording layer further contains an infrared absorbing agent.

12. The lithographic printing plate precursor according to claim 1, wherein the image recording layer further contains a polymerization initiator and a polymerizable compound.

13. The lithographic printing plate precursor according to claim 1, wherein the image recording layer further contains a binder polymer.

14. The lithographic printing plate precursor according to claim 1, further comprising: a protective layer on the image recording layer.

15. The lithographic printing plate precursor according to claim 14, wherein the protective layer contains an inorganic layered compound.

16. The lithographic printing plate precursor according to claim 1, wherein the image recording layer is a negative type image recording layer.

17. The lithographic printing plate precursor according to claim 1, wherein the image recording layer is an on-press development type image recording layer.

18. A method of preparing a lithographic printing plate, comprising: imagewise-exposing the lithographic printing plate precursor according to claim 1; and supplying at least one selected from the group consisting of printing ink and dampening water to remove an image recording layer of a non-image area on a printing press.

19. A method of preparing a lithographic printing plate, comprising: imagewise-exposing the lithographic printing plate precursor according to claim 1; and supplying at least one selected from the group consisting of printing ink and dampening water to remove an image recording layer of a non-image area on a printing press and preparing a lithographic printing plate; and performing printing using the obtained lithographic printing plate.

Description

EXAMPLES

[0339] Hereinafter, the present disclosure will be described in detail with reference to examples, but the present disclosure is not limited thereto. In the present examples, “%” and “part” respectively indicate “% by mass” and “part by mass” unless otherwise specified. Further, in a polymer compound, the molecular weight indicates the weight-average molecular weight (Mw) and the proportion of repeating constitutional units indicates mole percentage unless otherwise specified. Further, the weight-average molecular weight (Mw) is a value in terms of polystyrene obtained by performing measurement using gel permeation chromatography (GPC). Further, the average particle diameter indicates a volume average particle diameter unless otherwise specified.

[0340] <Synthesis of Particles P-1>

[0341] 270 parts of 1-methoxy-2-propanol, 9.0 parts of a compound A-3, 18.0 parts of a compound B-1, and 3.0 parts of a compound C-1 (n=90) were added to a three-neck flask, stirred in a nitrogen atmosphere, and heated to 70° C. Next, 0.3 g of dimethyl 2,2′-azobis(2-methylpropionate) was added thereto, and the mixture was continuously heated and stirred at 70° C. for 4 hours. 0.10 part of dimethyl 2,2′-azobis(2-methylpropionate) was added thereto, and the mixture was heated to 90° C. and allowed to further react for 4 hours.

[0342] The reaction solution was allowed to be naturally cooled to room temperature (25° C.), thereby obtaining a dispersion liquid of particles p-1 (solid content of 10%). The average particle diameter of the particle p-1 was 189 nm.

[0343] <Synthesis of Resin Particles P-2>

[0344] 113 parts of distilled water, 15.0 parts of a compound A-4, 4.0 parts of a compound B-2, and 1.0 part of a compound C-2 were added to a three-neck flask and heated to 70° C. in a nitrogen atmosphere. Next, 0.2 part of potassium persulfate (KPS) was added thereto, and the mixture was heated and stirred for 3 hours, further heated to 95° C., and allowed to react for 4 hours. The reaction solution was allowed to be naturally cooled to room temperature (25° C.), thereby obtaining a dispersion liquid of particles p-2 (solid content of 15%). The average particle diameter of the particles p-2 was 146 nm.

[0345] <Synthesis of Resin Particles P-3>

[0346] 20 parts of ion exchange water, 0.3 parts of Rongalit (sodium hydroxymethane sulfinate), 0.01 parts of disodium ethylenediamine tetraacetate, and 0.0025 parts of a ferrous sulfate heptahydrate were added to a three-neck flask, and the mixture was stirred at 60° C. and 250 rpm (revolutions per minute) in a nitrogen atmosphere.

[0347] Next, 3.0 parts of a compound A-1, 4.0 parts of a compound A-2, 13.0 parts of a compound B-3, 0.60 parts of sodium dodecylbenzene sulfonate, 0.58 parts of a peroxide polymerization initiator (trade name: PERBUTYL H, manufactured by NOF Corporation), and 17 parts of ion exchange water were added thereto, and the mixture was stirred for 30 minutes at room temperature, thereby preparing an emulsion. After 25% of the obtained emulsion was added to the three-neck flask for 30 minutes, the mixture was continuously heated and stirred for 30 minutes, and the remaining 75% of the emulsion was added dropwise thereto for 2 hours. After the completion of dropwise addition, the mixture was heated and stirred for 2 hours. The reaction solution was allowed to be naturally cooled to room temperature (25° C.), thereby obtaining a dispersion liquid of particles p-3 (solid content of 35%). The average particle diameter of the particles p-3 was 89 nm.

[0348] <Synthesis of Resin Particles P-4>

[0349] Particles p-4 were prepared in the same manner as that for the synthesis of the particles p-3 except that the monomers used were changed as listed in Table 1.

[0350] <Synthesis of Resin Particles P-5>

[0351] Particles p-5 were prepared in the same manner as that for the synthesis of the particles p-3 except that an anionic surfactant (trade name: PERSOFT (registered trademark) EK, manufactured by NOF Corporation) was used as the surfactant in place of the sodium dodecylbenzene sulfonate.

[0352] <Synthesis of Particles P-6>

[0353] -Synthesis of Pre-Coated Particles p-6′-

[0354] Particles p-6′ were prepared in the same manner as that for the synthesis of the particles p-3 except that the monomers used were changed as listed in Table 1. The concentration of solid contents of the particles p-6′ in the dispersion liquid was 35% by mass, and the average particle diameter of the particles p-6′ was 124 nm.

[0355] —-Synthesis of Particles P-6—

[0356] 12.5 parts of the dispersion liquid of the particles p-6′, 1.0 part of 4-hydroxybutyl acrylate glycidyl ether (E-1, 4HBAGE, manufactured by Mitsubishi Chemical Corporation), 0.2 parts of tetrabutylammonium bromide, and 30.0 parts of 1-methoxy-2-propanol were added to a three-neck flask and stirred at 90° C. for 12 hours. The reaction solution was allowed to be naturally cooled to room temperature (25° C.), thereby obtaining a dispersion of particles p-6 (solid content of 10%). The average particle diameter of the particles p-6 was 124 nm.

[0357] <Synthesis of Particles P-7> [0358] Synthesis of Pre-Coated Particles p-7′—

[0359] Particles p-7′ were prepared in the same manner as that for the synthesis of the particles p-3 except that the monomers used were changed as listed in Table 1. The concentration of solid contents of the particles p-7′ in the dispersion liquid was 35% by mass, and the average particle diameter of the particles p-7′ was 85 nm.

[0360] —Synthesis of Epoxy Polymer E-2—

[0361] 57.5 parts of 1-methoxy-2-prop anol and 25.0 parts of PME-4000 (methoxypolyethylene glycol methacrylate (n=approximately 9), manufactured by NOF Corporation) were added to a three-neck flask, heated to 80° C. in a nitrogen atmosphere, and stirred at 200 rpm. A solution consisting of 37.7 parts of 4HBAGE (manufactured by Mitsubishi Chemical Corporation), 2.0 parts of DPMP (dipentaerythritol hexakis(3-mercaptopropionate), manufactured by SC Organic Chemical Co., Ltd.), 0.35 parts of V-601 (dimethyl azobis(isobutyrate), manufactured by FUJIFILM Wako Pure Chemical Corporation), and 40.0 parts of 1-methoxy-2-propanol was added dropwise to the three-neck flask for 2 hours, and the mixture was heated and stirred for 2 hours.

[0362] Thereafter, 0.10 parts of V-601 was added thereto, and the mixture was heated to 90° C. and allowed to react for 4 hours, thereby obtaining a prepolymer solution.

[0363] Subsequently, 8.5 parts of acrylic acid, 0.075 g of 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (4 OH-TEMP 0), 1.9 parts of tetrabutylammonium bromide, 78.0 parts of 1-methoxy-2-propanol were added to the three-neck flask, and the mixture was allowed to react at 90° C. for 24 hours, thereby obtaining a polymer solution.

[0364] The weight-average molecular weight of the epoxy polymer E-2 in the polymer solution was 32000, and the solid content thereof was 30%.

[0365] —Synthesis of Particles p-7 (Coating Reaction)—

[0366] 12.5 parts of the particle solution p-7′ and 11.0 parts of ion exchange water were added to a three-neck flask and stirred at 75° C. 4.0 parts of the polymer solution was added dropwise thereto for 15 minutes, and the solution was heated and stirred for 8 hours. The reaction solution was allowed to be naturally cooled to room temperature (25° C.), thereby obtaining a dispersion liquid of particles p-7 (solid content of 20%). The average particle diameter of the particles p-7 was 90 nm.

[0367] <Synthesis of Particles P-8> [0368] —Synthesis of Pre-Coated Particles p-8′—

[0369] Particles p-8′ were prepared in the same manner as that for the synthesis of the particles p-3 except that the monomers used were changed as listed in Table 1 without adding a surfactant. The concentration of solid contents of the particles p-8′ in the dispersion liquid was 35% by mass, and the average particle diameter of the particles p-8′ was 105 nm. [0370] Synthesis of Hydrogen Bond Polymer E-3—

[0371] 42.5 parts of 1-methoxy-2-propanol was added to a three-neck flask, heated to 80° C. in a nitrogen atmosphere, and stirred at 200 rpm. A solution consisting of 30.0 parts of PME-1000 (methoxy polyethylene glycol methacrylate (n=approximately 23), manufactured by NOF Corporation), 13.3 parts of methacrylamide (MAm), 1.7 parts of DPMP (manufactured by SC Organic Chemical Co., Ltd.), 15.5 parts of glycidyl methacrylate, 0.3 parts of V-601 (manufactured by FUJIFILM Wako Pure Chemical Corporation), and 99.0 parts of 1-methoxy-2-propanol was added dropwise to the three-neck flask for 2 hours, and the solution was heated and stirred for 2 hours.

[0372] Thereafter, 0.10 parts of V-601 was added thereto, and the mixture was heated to 90° C. and allowed to react for 4 hours, thereby obtaining a prepolymer solution.

[0373] Subsequently, 8.0 parts of acrylic acid, 0.07 parts of 40H-TEMPO, 1.8 parts of tetrabutylammonium bromide, and 22.4 parts of 1-methoxy-2-propanol were added to the three-neck flask, and the solution was allowed to react at 90° C. for 24 hours, thereby obtaining a polymer solution.

[0374] The weight-average molecular weight of the hydrogen bond polymer E-3 in the polymer solution was 29000, and the solid content thereof was 30%. [0375] Synthesis of Particles p-8 (Coating Reaction)—

[0376] A dispersion liquid (solid content of 20%) of particles p-8 were obtained by carrying out a coating reaction in the same manner as that for the synthesis of the particles p-7 except that the polymer solution containing the hydrogen bond polymer E-3 was used. The average particle diameter of the particles p-8 was 111 nm. [0377] <Synthesis of Particles p-9 and p-13 to p-18>

[0378] Particles p-9 and p-13 to p-18 were respectively prepared in the same manner as that for the synthesis of the particle p-3 except that the monomers used were changed as listed in Table 1. [0379] <Synthesis of Particles p-10 to p-12>

[0380] The particles p-10 to p-12 were respectively prepared in the same manner as that for the synthesis of the particles p-7 except that the monomers used were changed as listed in Table 1. [0381] <Synthesis of Particles r-1>

[0382] Particles r-1 were prepared in the same manner as that for the synthesis of the particles p-2 except that the monomers used were changed as listed in Table 2.

[0383] <Synthesis of Particles r-2>

[0384] Particles r-2 were prepared in the same manner as that for the synthesis of the particles p-3 except that the monomers used were changed as listed in Table 2.

[0385] <Synthesis of particles r-3>

[0386] 10.0 parts of a compound C-1, 85.0 parts of distilled water, and 240.0 parts of n-propanol were added to a four-neck flask, and heated and stirred at 70° C. in a nitrogen atmosphere.

[0387] Next, a mixture of 20.0 parts of the compound B-1, 70.0 parts of the compound B-3, and 0.7 parts of 2,2′-azobisisobutyronitrile mixed in advance was added dropwise thereto for 2 hours. After the completion of the dropwise addition, the reaction was allowed to continue for 5 hours, 0.5 part of 2,2′-azobisisobutyronitrile was added to the solution, and the solution was heated to 80° C. 0.4 parts of 2,2′-azobisisobutyronitrile was added thereto every 6 hours, and the solution was allowed to react for a total of 19 hours.

[0388] The reaction solution was allowed to be naturally cooled to room temperature (25° C.), thereby obtaining a dispersion liquid of particles r-3 (solid content of 23%). The average particle diameter of the particles r-3 was 150 nm.

TABLE-US-00001 TABLE 1 Average Composition of particles particle Unit A Unit B Unit C Surface diameter Particles Type Amount Type Amount Type Amount modification (nm) p-1 A-3 30 B-1 60 C-1 (n = 90) 10 — 189 p-2 A-4 75 B-2 20 C-2 5 — 146 p-3 A-1/A-2 15/20 B-3 65 — 0 — 89 p-4 A-2/A-5 40/5  B-4 40 C-1 (n = 45) 15 — 115 p-5 A-6 35 B-5 45 C-1 (n = 23) 20 — 135 p-6 A-7/A-8 30/10 B-3 50 — 10 E-1 124 p-7 A-2/A-8 20/20 B-1 50 C-1 (n = 90) 10 E-2 90 p-8 A-9 50 B-1 40 C-2 10 E-3 111 p-9 A-2 25 B-1/B-2 60/10 C-1 (n = 23) 5 — 164 p-10 A-2/A-8 20/10 B-1 45 C-1 (n = 90) 10 E-2 102 p-11 A-2/A-8 10/10 B-1 40 C-1 (n = 90) 10 E-2 99 p-12 A-10 30 B-4 50 C-3 20 E-2 124 p-13 A-2/A-8 20/20 B-1 50 C-1 (n = 90) 10 — 116 p-14 A-2 30 B-1 70 C-1 (n = 90) 10 — 135 p-15 A-1 30 B-1 70 C-1 (n = 90) 10 — 85 p-16  A-12 30 B-1 70 C-1 (n = 90) 10 — 92 p-17 A-2 30 B-1 70 C-2 10 — 100 p-18 A-2 30 B-1 70 C-3 10 — 160

TABLE-US-00002 TABLE 2 Average Composition of particles particle Unit A Unit B Unit C Surface diameter Particles Type Amount Type Amount Type Amount modification (nm) r-1 A-3 10 B-4 80 C-1 (n = 90) 10 — 135 r-2 A-2 20 B-3 80 — 0 — 164 r-3 — 0 B-1/B-3 20/70 C-1 (n = 45) 10 — 150

[0389] The details of the abbreviations in Tables 1 and 2 are as follows. Further, the kind of each unit composition is described using monomers, but the corresponding constitutional units (the above-described constitutional units) are used in the addition polymerization type resin in the prepared particles. Further, the unit of the amount in each unit is parts by mass, which is the amount as a constitutional unit.

[0390] Unit A: constitutional unit A having hydrogen bond-donating site

[0391] Unit B: constitutional unit other than constitutional unit A having hydrogen bond-donating site and constitutional unit containing hydrophilic group.

[0392] Unit C: constitutional unit containing hydrophilic group

[0393] A-1 to A-9 and A-12: compounds shown below

##STR00013##

[0394] B-1 to B-5: compounds shown below

##STR00014##

[0395] C-1 and C-2: compounds shown below (n represents the number listed in Table 1 or Table 2)

##STR00015##

[0396] C-3: compound shown below (C.sub.10 to C.sub.14 represent an alkyl group having 10 to 14 carbon atoms, and C-3 is a mixture thereof).

##STR00016##

[0397] <Preparation of Supports a to D>

[0398] In order to remove rolling oil on a surface of an aluminum plate (Material JIS A 1050) having a thickness of 0.3 mm, a degreasing treatment was performed using a 10 mass % sodium aluminate aqueous solution at 50° C. for 30 seconds, the surface of the aluminum plate was grained using three bundled nylon brushes having a diameter of 0.3 mm and a pumice water suspension (specific gravity of 1.1 g/cm.sup.3) having a median diameter of 25 μm and then sufficiently washed with water. The aluminum plate was etched by being immersed in a 25 mass % sodium hydroxide aqueous solution at 45° C. for 9 seconds, washed with water, further immersed in a 20 mass % nitric acid aqueous solution at 60° C. for 20 seconds, and washed with water. The etching amount of the grained surface was approximately 3 g/m.sup.2.

[0399] Next, an electrochemical roughening treatment was continuously performed using an AC voltage of 60 Hz. As the electrolytic solution, a 1 mass % nitric acid aqueous solution (including 0.5% by mass of aluminum ions) was used at a liquid temperature of 50° C. Using a trapezoidal rectangular waveform AC having a time TP, until the current value reached a peak from zero, of 0.8 msec and a duty ratio of 1:1 as the AC power source waveform, the electrochemical roughening treatment was performed using a carbon electrode as a counter electrode. As an auxiliary anode, ferrite was used. The current density was 30 A/dm.sup.2 in terms of the peak current value, and 5% of the current from the power source was separately flowed to the auxiliary anode. The electric quantity in the nitric acid electrolysis was 175 C/dm.sup.2 which is an electric quantity in a case where the aluminum plate was an anode. Thereafter, the aluminum plate was washed with water using a spray.

[0400] Next, an electrochemical roughening treatment was performed according to the same method as the method for nitric acid electrolysis under the condition of an electric quantity of 50 C/dm.sup.2 in a case where an aluminum plate is an anode in a 0.5 mass % hydrochloric acid aqueous solution (including 0.5% by mass of aluminum ions) and an electrolytic solution at a liquid temperature of 50° C. Subsequently, washing with water using a spray was performed.

[0401] Next, 2.5 g/m.sup.2 of a DC anodized film was formed on the aluminum plate at a current density of 15 A/dm.sup.2 using a 15 mass % sulfuric acid aqueous solution (including 0.5% by mass of aluminum ions) as an electrolytic solution, washed with water, and then dried, thereby preparing a support A. The average pore diameter (surface average pore diameter) in the surface layer of the anodized film was 10 nm.

[0402] The pore diameter in the surface layer of the anodized film was measured by observing the surface at a magnification of 150000 times using an ultra-high resolution type SEM (S-900, scanning electron microscope, manufactured by Hitachi, Ltd.) without performing a vapor deposition treatment and the like to impart the conductivity at a relatively low acceleration voltage of 12 V, randomly extracting 50 pores, and acquiring the average value thereof. The standard deviation of errors was ±10% or less.

[0403] Thereafter, in order to ensure the hydrophilicity of a non-image area, a silicate treatment was performed on the support A using 2.5% by mass of a No. 3 sodium silicate aqueous solution at 60° C. for 10 seconds, and the support was washed with water, thereby preparing a support B. The adhesion amount of Si was 10 mg/m.sup.2. The center line average roughness (Ra) of the support B was measured using a needle having a diameter of 2 μm, and the value was 0.51 μm.

[0404] A support C was prepared according to the same method as the method of preparing the support A except that the electrolytic solution in a case of forming a DC anodized film was changed to a 22 mass % phosphoric acid aqueous solution in the preparation of the support C. The average pore diameter (surface average pore diameter) in the surface layer of the anodized film was 25 nm as measured according to the same method as described above.

[0405] Thereafter, in order to ensure the hydrophilicity of a non-image area, a silicate treatment was performed on the support C using 2.5% by mass of a No. 3 sodium silicate aqueous solution at 60° C. for 10 seconds, and the support was washed with water, thereby preparing a support D. The adhesion amount of Si was 10 mg/m.sup.2. The center line average roughness (Ra) of the support D was measured using a needle having a diameter of 2 μm, and the value was 0.52 μm.

[0406] <Preparation of Support E>

[0407] An aluminum alloy plate made of the material 1S with a thickness of 0.3 mm was subjected to (A-a) mechanical roughening treatment (brush grain method) described in paragraph 0126 of JP2012-158022A to (A-i) desmutting treatment in an acidic aqueous solution described in paragraph 0134 of JP2012-158022.

[0408] Next, an anodized film which had large-diameter pores with an average diameter of 35 nm and a depth of 100 nm and small-diameter pores with an average diameter of 10 nm and a depth of 1000 nm and in which the ratio of the depth of the large-diameter pores to the average diameter of the large-diameter pores was 2.9 was formed by appropriately adjusting conditions for treatments from the first stage anodization treatment (A j) described in paragraph 0135 of JP2012-158022A to the third stage anodization treatment (A-m) described in paragraph 0138 of JP2012-158022A, thereby obtaining an aluminum support E.

[0409] Moreover, during all treatment steps, a water washing treatment was performed, and liquid draining was performed using a nip roller after the water washing treatment.

[0410] (Example 1 to 23 and Comparative Examples 1 to 4)

[0411] <Formation of Undercoat Layer>

[0412] The support listed in Table 3 or Table 4 was coated with an undercoat layer coating solution (1) having the following composition such that the dry coating amount was set to 20 mg/m.sup.2, thereby forming an undercoat layer.

[0413] —Undercoat Layer Coating Solution (1)— [0414] Polymer (P-1) [structure shown below]: 0.18 parts [0415] Hydroxyethyliminodiacetic acid: 0.10 parts [0416] Water: 61.4 parts

##STR00017##

[0417] <Preparation of Lithographic Printing Plate Precursor>

[0418] The lithographic printing plate precursors of Examples 1 to 13 and Comparative Examples 1 to 4 were respectively prepared by the following method.

[0419] The undercoat layer was bar-coated with each image recording layer coating solution (solid content of 6%) having the composition listed in Table 3 or 4 and dried in an oven at 120° for 40 seconds, thereby forming an image recording layer having a dry coating amount of 1.0 g/m.sup.2.

[0420] The image recording layer was bar-coated with the protective layer coating solution having the above-described composition and dried in an oven at 120° C. for 60 seconds, thereby forming a protective layer having a dry coating amount of 0.15 g/m.sup.2.

[0421] In the examples in which the protective layers were formed, “present” is noted in the columns of the protective layers in Table 3 or Table 4.

[0422] <Formation of Protective Layer>

[0423] The image recording layer was bar-coated with a protective layer coating solution having the following composition and dried in an oven at 120° C. for 60 seconds, thereby forming a protective layer having a dry coating amount of 0.15 g/m.sup.2. [0424] —Protective Layer Coating Solution— [0425] Inorganic layered compound dispersion liquid (1) (described below): 1.5 parts [0426] Polyvinyl alcohol (CKS50, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., sulfonic acid-modified, saponification degree of 99% by mole or greater, degree of polymerization of 300), 6 mass % aqueous solution: 0.55 parts [0427] Polyvinyl alcohol (PVA-405, manufactured by Kuraray Co., Ltd., saponification degree of 81.5% by mole, degree of polymerization of 500), 6 mass % aqueous solution: 0.03 parts [0428] Surfactant (EMALEX 710, manufactured by Nihon Emulsion Co., Ltd., polyoxyethylene lauryl ether), 1 mass % aqueous solution): 0.86 parts by mass [0429] Ion exchange water: 6.0 parts

[0430] The method of preparing the inorganic layered compound dispersion liquid (1) is described below.

[0431] <Preparation of Inorganic Layered Compound Dispersion Liquid (1)>

[0432] 6.4 parts of synthetic mica (SOMASIF ME-100, manufactured by CO-OP CHEMICAL CO., LTD.) was added to 193.6 g of ion exchange water and dispersed such that the average particle diameter (laser scattering method) was set to 3 μm using a homogenizer. The aspect ratio of the obtained dispersed particles was 100 or greater.

[0433] <Evaluation of Lithographic Printing Plate Precursor>

[0434] [UV Printing Durability]

[0435] The lithographic printing plate precursor prepared in the above-described manner was exposed with Magnus 800 Quantum (manufactured by Kodak Japan Ltd.) equipped with an infrared semiconductor laser under conditions of an output of 27 W, an external drum rotation speed of 450 rpm, and a resolution of 2400 dpi (dot per inch, 1 inch=2.54 cm) (irradiation energy of approximately 110 mJ/cm.sup.2). The exposed image was designed to include a solid image and a chart of AM screen (Amplitude Modulated Screening) 3% halftone dots.

[0436] The obtained exposed precursor was attached to the cylinder of a printing press SX-74 (manufactured by Heidelberg Co.) having a medium octavo size without being subjected to a development treatment. The present printing press was connected to a dampening water circulation tank having a capacity of 100 L and including a nonwoven fabric filter and a temperature control device. The circulation device was charged with 80 L of dampening water containing 2.0% of dampening water S-Z1 (manufactured by FUJIFILM Corporation), dampening water and ink were supplied using T & K UV OFS K-HS ink GE-M (manufactured by T&K TOKA Co., Ltd.) as printing ink according to a standard automatic printing start method, and printing was performed on Tokubishi Art (manufactured by Mitsubishi Paper Mills Ltd., ream weight of 76.5 kg) paper at a printing speed of 10000 sheets per hour.

[0437] As the number of printed sheets increased, the image area was gradually worn, and thus the ink density on the printed material decreased. The number of printed sheets in a case where the value obtained by measuring the halftone dot area ratio of AM screen 3% halftone dots using a Gretag densitometer (manufactured by GretagMacbeth) in the printed material was decreased by 1% than the measured value of the 500th printed sheet was defined as the number of completely printed sheets, and the printing durability was evaluated. The evaluation was performed based on the relative printing durability in which a case where the number of printed sheets was 50000 was rated as 100. The UV printing durability is more excellent as the numerical value increases.

[0438] Relative printing durability=(number of printed sheets of target lithographic printing plate precursor)/50000×100

[0439] [Scratch Resistance]

[0440] A continuous weighting type scratch resistance strength tester TYPE: 18 (manufactured by Shinto Scientific Co., Ltd.) was used.

[0441] A 3 cm scratch test was performed using a sapphire needle (r0.03 mm) at a load of 200 g and a moving speed of 600 mm/min with reference to the scratch test ISO 12137-2-1997. After performing the scratch test on 10 places of each sample image area, the sample was exposed and printed under the conditions for the above-described UV durability test, and the number of chips on the straight line appearing in the image area on the 2000th printed sheet was counted. The scratch resistance is excellent as the number of chips decreases.

TABLE-US-00003 TABLE 3 Composition of image recording layer coating solution Infrared Acid Polymerization absorbing Polymerization color Polymerizable Binder Sensitizing Particles assistant agent initiator former compound polymer agent (parts) (parts) (parts) (parts) (parts) (parts) (parts) (parts) Example 1 p-1 J-2 K-1 I-2 — M-4 BI-1 — (250) (40) (46) (121) (120) (80) Example 2 p-2 J-1 K-2 I-1 — M-2 — CL-2 (310) (32) (20) (119) (120) (15) Example 3 p-3 J-1 K-1 I-2 H-1 M-1/M-5 BI-1 — (150) (33) (29) (62) (25) (160/30) (150) Example 4 p-4 J-3 K-3 I-1 H-2 M-3 — CL-3 (240) (19) (41) (90) (48) (210) (22) Example 5 p-5 J-5 K-3 I-3 H-3 M-2 BI-1 — (200) (15) (9) (60) (33) (90) (200) Example 6 p-6 J-1 K-3 I-2 H-4 M-3 BI-1 — (400) (30) (37) (160) (60) (250) (120) Example 7 p-7 J-2/J-1 K-1 I-2 — M-1/M-3 — CL-1 (410) (25/20) (45) (75) (24/40) (20) Example 8 p-8 J-2 K-1 I-1 — M-2 — — (130) (41) (28) (90) (168) Example 9 p-9 J-4 K-1 I-3 — M-5 — — (360) (33) (31) (41) (56) Example 10 P-1/P-3 J-1 K-2 I-1 — M-3 BI-1 CL-1/CL-2 (150/150) (38) (57) (80) (100) (140) (20/6) Example 11 p-7/p-5 — K-2 I-2 — M-3/M-4/M-5 — — (120/170) ※ (20) (60) 80/20/90 Example 12 P-7/G-1 J-1 K-1 I-3 — M-2/M-3/M-5 BI-1 — (120/130) (25) (41) (115) (50/60/25) (160) Example 13 p-7/r-3 J-2 K-3 I-3 — M-2 BI-1 — (120/150) (29) (41) (79) (70/20) (130) Comparison r-1 — K-1 I-3 — M-2 BI-1 — example 1 (250) (25) (35) (180) (210) Comparison r-2 J-1 K-3 I-2 — M-4/M-5 — — example 2 (260) (40) (38) (50) (190/30) Comparison r-3 J-1 K-2 I-2 — M-3 BI-1 CL-1 example 3 (300) (45) (30) (100) (140) (150) (18) Comparison r-3 J-1 K-1 I-1 — M-1/M-4 BI-1 CL-1 example 4 (350) (30) (21) (110) (150/40) (60) (32) Evaluation result Composition of image recording layer coating solution Absence or UV Scratch Hydrophilic Type presence of printing resistance compound Solvent of protective durability (number of (parts) (mass ratio) support layer (%) scratches) Example 1 — S-2/S-5/S-1 A Present 80 0 (40/10/50) Example 2 — S-3/S-4 B — 86 0 (40/60) Example 3 T-2 S-3/S-4/S-1 C Present 82 1 (22) (40/40/20) Example 4 — S-3/S-4/S-1 D — 90 0 (40/40/20) Example 5 T-1 S-3/S-4/S-5 A Present 81 0 (30) (20/40/50) Example 6 — S-3/S-4/S-5 C — 95 0 (70/20/10) Example 7 T-2 S-1/S-2 D — 101 0 (27) (20/100) Example 8 — S-1/S-2/S-3 A — 98 1 (50/30/10) Example 9 T-3/T-2/T-1 S-1/S-3/S-4/S-5 E — 98 0 (20/32/10) (60/20/15/5) Example 10 — S-1/S-2 E — 105 0 (70/30) Example 11 T-3 S-4/S-5 B — 100 1 (70) (50/50) Example 12 — S-1/S-2/S-4/S-5 A — 99 0 (80/10/5/5) Example 13 — S-1/S-3 C — 90 0 (50/50) Comparison T-3 S-4/S-5 B — 20 7 example 1 (18) (50/50) Comparison — S-2/S-5 E — 33 8 example 2 (15/85) Comparison — S-1/S-3 A — 61 4 example 3 (90/10) Comparison T-1/T-2 S-1/S-2/S-3 C Present 66 5 example 4 (10/20) (25/25/50)

TABLE-US-00004 TABLE 4 Composition of image recording layer coating solution Infrared Polymerization absorbing Polymerization Polymerizable Binder Sensitizing Particles assistant agent initiator Acid color compound polymer agent (parts) (parts) (parts) (parts) former (parts) (parts) (parts) Example 10 p-7 J-1 K-3 I-1 H-1 M-1/M-5 — — (300) (40) (40) (160) (60) (160/30) Example 11 p-10 J-1 K-3 I-1 H-1 M-1/M-5 — — (300) (40) (40) (160) (60) (160/30) Example 12 p-11 J-1 K-3 I-1 H-1 M-1/M-5 — — (300) (40) (40) (160) (60) (160/30) Example 13 p-12 J-1 K-3 I-1 H-1 M-1/M-5 — — (300) (40) (40) (160) (60) (160/30) Example 18 p-13 J-1 K-3 I-1 H-1 M-1/M-5 — — (300) (40) (40) (160) (60) (160/30) Example 19 p-14 J-1 K-3 I-1 H-1 M-1/M-5 — — (300) (40) (40) (160) (60) (160/30) Example 20 p-15 J-1 K-3 I-1 H-1 M-1/M-5 — — (300) (40) (40) (160) (60) (160/30) Example 21 p-16 J-1 K-3 I-1 H-1 M-1/M-5 — — (300) (40) (40) (160) (60) (160/30) Example 22 p-17 J-1 K-3 I-1 H-1 M-1/M-5 — — (300) (40) (40) (160) (60) (160/30) Example 23 p-18 J-1 K-3 I-1 H-1 M-1/M-5 — — (300) (40) (40) (160) (60) (160/30) Evaluation result Composition of image recording layer coating solution Absence or UV Scratch Hydrophilic presence of printing resistance compound Solvent Type of protective durability (number of (parts) (mass ratio) support layer (%) scratches) Example 10 — S-1/S-2/S-3 E — 100 0 (50/30/10) Example 11 — S-1/S-2/S-3 E — 95 0 (50/30/10) Example 12 — S-1/S-2/S-3 E — 90 0 (50/30/10) Example 13 — S-1/S-2/S-3 E — 84 0 (50/30/10) Example 18 — S-1/S-2/S-3 E — 95 0 (50/30/10) Example 19 — S-1/S-2/S-3 E — 92 0 (50/30/10) Example 20 — S-1/S-2/S-3 E — 87 0 (50/30/10) Example 21 — S-1/S-2/S-3 E — 80 1 (50/30/10) Example 22 — S-1/S-2/S-3 E — 85 1 (50/30/10) Example 23 — S-1/S-2/S-3 E — 91 0 (50/30/10)

[0442] Based on the results listed in Tables 3 and 4, it was found that the lithographic printing plate precursors according to the embodiment of the present disclosure shown in the examples had excellent UV printing durability compared to the lithographic printing plate precursors of the comparative examples.

[0443] Further, based on the results listed in Tables 3 and 4, the lithographic printing plate precursors according to the embodiment of the present disclosure shown in the examples also had excellent scratch resistance.

[0444] Further, “” in Table 3 indicates that the solution contains a tetraphenylborate anion derived from K-2 and I-2.

[0445] The details of each compound listed in Table 3 or Table 4 other than those described above are described below.

[0446] [Infrared Absorbing Agent]

[0447] K-1 to K-3: compounds having the following structures

##STR00018##

[0448] In the structures shown above, Ph represents a phenyl group.

[0449] [Electron-accepting polymerization initiator]

[0450] I-1 to I-3: compounds having the following structures

##STR00019##

[0451] In the structures shown above, TsO.sup.− represents a tosylate anion.

[0452] [Electron-donating polymerization initiator (polymerization assistant)]

[0453] J-1 to J-5: compounds having structures shown below

##STR00020##

[0454] In the structures shown above, Ph represents a phenyl group, and Bu represents a butyl group.

[0455] [Acid Color Former]

[0456] H-1: S-205 (manufactured by Fukui Yamada Chemical Co., Ltd.)

[0457] H-2: GN-169 (manufactured by Yamamoto Chemicals Inc.)

[0458] H-3: Black-XV (manufactured by Yamamoto Chemicals Inc.)

[0459] H-4: Red-40 (manufactured by Yamamoto Chemicals Inc.)

[0460] [Polymerizable Compound]

[0461] M-1: tris(acryloyloxyethyl) isocyanurate, NK ESTER A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.

[0462] M-2: dipentaerythritol pentaacrylate, SR-399, manufactured by Sartomer Japan Inc.

[0463] M-3: dipentaerythritol hexaacrylate, A-DPH, manufactured by Shin-Nakamura Chemical Co., Ltd.

[0464] M-4: dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer, UA-510H, manufactured by Kyoeisha Chemical Co., Ltd.

[0465] M-5: ethoxylated pentaerythritol tetraacrylate, ATM-4E, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.

[0466] [Polymer Compound]

[0467] Polymer compound BI-1 (having structure shown below, Mw: 35000, n=2 (number of EO units))

##STR00021##

[0468] [Polymer Particles]

[0469] G-1: An image recording layer coating solution containing a microgel (1) described below and polymer particles G-1 (microgel (1)) was prepared by mixing a composition obtained by mixing the components listed in Table 3 other than the microgel solution with the microgel solution so as to have the composition listed in Table 3 immediately before application and stirring the mixture.

[0470] —Preparation of Microgel Solution— [0471] Microgel (1) (polymer particles G-1): 2.640 parts [0472] Distilled water: 2.425 parts

[0473] A method of preparing the microgel (1) used in the microgel solution is described below. [0474] —Preparation of Polyvalent Isocyanate Compound (1)—

[0475] 43 mg of bismuth tris(2-ethylhexanoate) (NEOSTANN U-600, manufactured by NITTO KASEI CO., LTD.) was added to an ethyl acetate (25.31 g) suspension solution of 17.78 g (80 mmol) of isophorone diisocyanate and 7.35 g (20 mmol) of the following polyhydric phenol compound (1), and the resulting solution was stirred. The reaction temperature was set to 50° in a case of heat generation being subsided, and the solution was stirred for 3 hours, thereby obtaining an ethyl acetate (50% by mass) solution of a polyvalent isocyanate compound (1).

##STR00022##

[0476] —Preparation of Microgel (1)—

[0477] The oil phase components and the water phase components were mixed with each other and emulsified at 12000 rpm for 10 minutes using a homogenizer. The obtained emulsion was stirred at 45° C. for 4 hours, 5.20 g of a 10 mass % aqueous solution of 1,8-diazabicyclo[5.4.0]undeca-7-ene-ocrylate (U-CAT SA102, manufactured by San-Apro Ltd.) was added thereto, and the solution was stirred at room temperature for 30 minutes and allowed to stand at 45° C. for 24 hours. The concentration of solid contents was adjusted to 20% by mass using distilled water, thereby obtaining an aqueous dispersion liquid of the microgel (1). The average particle diameter thereof was measured by the light scattering method, and the value was 0.28

[0478] ˜Oil Phase Component˜

[0479] (Component 1) ethyl acetate: 12.0 parts

[0480] (Component 2) adduct (50 mass % ethyl acetate solution, manufactured by Mitsui Chemicals, Inc.) obtained by adding trimethylolpropane (6 molar equivalents) and xylene diisocyanate (18 molar equivalents) and adding methyl one-terminal polyoxyethylene (1 molar equivalent, repetition number of oxyethylene units: 90) thereto: 3.76 parts

[0481] (Component 3) polyvalent isocyanate compound (1) (as 50 mass % ethyl acetate solution): 15.0 parts

[0482] (Component 4) 65 mass % solution of dipentaerythritol pentaacrylate (SR-399, manufactured by Sartomer Japan Inc.) in ethyl acetate: 11.54 parts

[0483] (Component 5) 10% solution of sulfonate type surfactant (PIONINE A-41-C, manufactured by TAKEMOTO OIL & FAT Co., Ltd.) in ethyl acetate: 4.42 parts

[0484] ˜Water Phase Component˜

[0485] Distilled water: 46.87 parts

[0486] [Hydrophilic Compound]

[0487] T-1: tris(2-hydroxyethyl) isocyanurate

[0488] T-2: compound having the following structure

[0489] T-3: hydroxypropyl cellulose, Klucel M, manufactured by Hercules, Inc.

##STR00023##

[0490] [Sensitizing Agent]

[0491] CL-1: compound having structure shown below

[0492] CL-2: benzyl dimethyl octyl ammonium.PF.sub.6 salt

[0493] CL-3: compound having structure shown below

##STR00024##

[0494] [Solvent]

[0495] S-1: 2-butanone (MEK)

[0496] S-2: 1-methoxy-2-propanol (MFG)

[0497] S-3: methanol

[0498] S-4: 1-propanol

[0499] S-5: distilled water

[0500] The disclosure of JP2019-016540 filed on Jan. 31, 2019 is incorporated herein by reference in its entirety.

[0501] All documents, patent applications, and technical standards described in the present specification are incorporated herein by reference to the same extent as in a case of being specifically and individually noted that individual documents, patent applications, and technical standards are incorporated by reference.