JP2006058835A - Positive photosensitive composition for lithographic printing plate and developer composition for same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high sensitivity, high resolution and high performance photosensitive composition for use in a thermal type positive CTP lithographic printing plate suitable for direct recording with a laser in an infrared region, and to provide a developer composition suitable for developing the photosensitive composition. <P>SOLUTION: The positive photosensitive composition for a lithographic printing plate comprises a binder polymer having solubility in an alkaline developer, an infrared absorbent which absorbs infrared radiation and generates heat, a thermal acid generator which is decomposed by heat generated by the infrared absorbent to produce an acid, a dissolution inhibitor which has a dissolution inhibiting effect on the binder polymer but loses its dissolution inhibiting power upon decomposition by heat or an acid, and a solvent, wherein the thermal acid generator is selected from a 2,1-diazonaphthoquinone-4-sulfonic ester derivative, a sulfonium salt having an anionic moiety which generates an organic acid, an iodonium salt having an anionic moiety which generates an organic acid or the mixture of these. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a positive photosensitive composition for a lithographic printing plate. More specifically, the present invention relates to a CTP (computer-to-plate) that is exposed to a semiconductor laser in the infrared region of 600 nm to 1,300 nm or a YAG (yttrium aluminum garnet) laser. The present invention relates to a positive photosensitive composition for a lithographic printing plate and a developer composition therefor.

  CTP laser-sensitive direct plate making by directly irradiating a printing plate (pre-sensitized plate) coated with a photosensitive composition directly without laser masks has high resolution and high productivity. Although there are various advantages such as being able to cope effectively, there are the following documents regarding the photosensitive composition used in such CTP laser photosensitive direct plate making.

  Patent Documents 1 and 2 include 2,1-diazonaphthoquinone-5-sulfonic acid ester and 2,1-diazonaphthoquinone-4-sulfonyl chloride (2 , 1-diazo-napthoquinone-4-sulfonyl chloride) and amide organic dyes are disclosed.

  In Patent Documents 3 to 5, unlike conventional typical positive type lithographic printing plates in which an image is formed by photolysis of a 2,1-diazonaphthoquinone-5-sulfonic acid ester derivative, a photosensitive material containing an infrared absorber is disclosed. A thermal mode positive photosensitive lithographic printing plate is disclosed in which a positive image is obtained by irradiating an irradiating composition with an infrared laser.

  Patent Document 6 discloses a photosensitive composition for a lithographic printing plate, which contains a photoacid generator and an infrared absorbing dye, and always contains both a resole resin and a novolak resin as a binder. Patent Document 7 discloses a photoacid generator. A photosensitive composition for a lithographic printing plate is disclosed that contains s-triazine and an infrared-absorbing dye as a generator and necessarily contains both a resole resin and a novolac resin as a binder. However, the acid generated by exposure is not involved in any acid-catalyzed reaction, and there is no specific example for realizing the positive pattern, and the resol resin and the novolak resin are cured even when the negative pattern is to be realized. A separate heating process is absolutely necessary to make it happen.

  Patent Document 8 discloses a photosensitive composition containing an alkali-soluble resin containing novolak and an onium salt such as a sulfonium salt.

  Originally, onium salts are acid generators that generate acid by being decomposed by light or heat, but in this patent, they are not used as acid generators, but are used in conventional typical positive photosensitive lithographic printing plates. Similar to the 2,1-diazonapthoquinone-5-sulfonic acid ester derivative used, based on the inhibitory effect on dissolution of novolac and solubilization in alkaline developer by direct photolysis It only acts as a PAC (photoactive compound).

Patent Document 9 discloses a photosensitive composition containing a compound capable of generating an acid upon exposure, a compound having a functional group that is decomposed by an acid, and an infrared absorber. A diazonium salt as an acid generator, Among the phosphonium salts, sulfonium salts, and iodonium salts, salts whose anion portions are BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SiF ₆ ²⁻ , ClO ₄ ⁻ , organic halogen acid generators, triazines And organic halogen-based acid generators of oxadiazoles are disclosed.

  In particular, the above document describes an example in which 2,1-diazonaphthoquinone-4-sulfonyl chloride is used as a thermal acid generator in a thermal type CTP photosensitive composition together with an infrared absorbing dye. -Diazonaphthoquinone-4-sulfonyl chloride is difficult to use in practice because of its low decomposition temperature and danger of explosion during handling, and there is no example for this. Nor.

  In addition, Non-Patent Document 1 describes an example in which a sulfonium salt having a t-BOC group introduced in the side chain is used as a photoacid generator, and Non-Patent Document 2 describes 2,1-diazonaphthoquinone. It describes that -4-sulfonic acid ester derivatives can be used as photoacid generators.

  However, sulfonium salts and 2,1-diazonaphthoquinone-4-sulfonic acid ester derivatives introduced with a t-BOC group in the side chain reported as photoacid generators in the above literature are ultraviolet (UV) or deep ultraviolet (DUV). An acid is generated by irradiation of the above, and the photosensitive composition does not contain an infrared absorber.

Japanese Unexamined Patent Publication No. Sho 50-36209 US Pat. No. 3,969,118 Japanese Unexamined Patent Publication No. 10-268512 Japanese Unexamined Patent Publication No. 2002-189292 Japanese Unexamined Patent Publication No. 60-175046 Japanese Unexamined Patent Publication No. 7-020629 Japanese Unexamined Patent Publication No. 7-271029 U.S. Pat. No. 4,708,925 Japanese Unexamined Patent Publication No. 11-65105 Polymeric Materials Science and Engineering (R. Schwalm, Proceedings, ACS division, 61, 278, 1989) Polymeric Materials Science and Engineering (F.A.Vollenbrock etc., Proceedings, ACS division, 61, 283, 1989)

  Accordingly, an object of the present invention is to provide a high sensitivity and high resolution for use in a thermal type positive CTP lithographic printing plate suitable for direct recording by an infrared region of 600 nm to 1,300 nm, particularly a semiconductor laser or a YAG laser. It is to provide an image, a high-performance photosensitive composition and a developer composition suitable for the development thereof.

  In order to achieve the above object, the positive photosensitive composition for a lithographic printing plate of the present invention is generated by a binder polymer that is soluble in an alkali developer, an infrared absorber that absorbs infrared rays and generates heat, and an infrared absorber. A lithographic printing comprising a thermal acid generator that decomposes with heat and generates an acid, a dissolution inhibitor that has a dissolution inhibiting effect on the binder polymer, but loses its dissolution inhibiting power when decomposed by heat or acid, and a solvent In a positive photosensitive composition for a plate, the thermal acid generator is a 2,1-diazonaphthoquinone-4-sulfonic acid ester derivative, a sulfonium salt having an anion portion that generates an organic acid, an anion portion that generates an organic acid It is selected from iodonium salts having the above or a mixture thereof.

  According to the present invention, a high-sensitivity, high-resolution photosensitive composition suitable for direct recording by a 600 nm to 1,300 nm infrared region semiconductor laser or YAG laser and a developer composition suitable for development thereof are provided. .

  In addition, since it is not necessary to perform a heat treatment after the exposure, the process becomes simple, and the reaction is started by the infrared absorber absorbing the infrared ray, so that it is possible to work under a white light instead of a yellow light. There is an advantage.

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

  The thermal acid generator is decomposed by the heat generated when the infrared absorber absorbs infrared rays to generate an acid, thereby losing the dissolution inhibiting function of the dissolution inhibitor with respect to the binder polymer and dissolving the exposed portion to form a pattern. However, when a 2,1-diazonaphthoquinone-4-sulfonic acid ester derivative is used, it is particularly effective to be selected from compounds having structures of the following formulas (a) to (n). In this case, it is used at a ratio of 0.05 to 20 parts by weight with respect to 100 parts by weight of the binder polymer.

(In the formula, D represents the following formula (o)

で表される。但し、構造式中にＤが複数ある場合、全部はもちろん、一部がＤであるものを含み、Ｄが上記式（ｏ）でない場合は水素である。）

It is represented by However, when there are a plurality of D in the structural formula, all of them include, of course, a part of which is D, and when D is not the above formula (o), it is hydrogen. )

  The 2,1-diazonaphthoquinone-4-sulfonic acid ester derivative is a compound described in Polymer Materials Science and Engineering (FA Vollenbrock etc., Proceedings, ACS division, 61, 283, 1989). The present invention is clearly different from the present invention in which an acid is generated by heat generated by absorbing an infrared ray in that it is a photoacid generator that generates an acid by being decomposed by ultraviolet rays (UV).

  The sulfonium salt having an anion that generates an organic acid is selected from the following formula (p) or a compound having the structure of the following formulas (q) and (r), and is 0.05 to 100 parts by weight with respect to 100 parts by weight of the binder polymer. It is used at a ratio of 20 parts by weight. In particular, sulfonium salts selected from the groups represented by the following formulas (q) and (r) are effective, but these sulfonium salts are thermally decomposed by heat generated by the infrared absorber and t by the generated acid. Based on the intramolecular acid-catalyzed decomposition of the BOC group, it realizes high sensitivity, high resolution, and high contrast of the resist, and is excellent in dissolution inhibition effect, so it is used alone or with a dissolution inhibitor.

(In the formula, X is an anion moiety that releases an organic acid, and includes methane sulfonate, trifluoromethanesulfonate, p-toluenesulfonate, 10-camphorsulfonate (10-camphorsulfonate). ), Or perfluoro-1-butanesulfonate, and R ₁ , R ₂ , and R ₃ are each a hydrogen atom, a nitro group, a C ₁ -C ₄ alkyl group, or C ₁ -C ₄ alkoxy groups, which may be the same or different.)

(In the formula, X is an anion moiety that releases an organic acid, and includes methane sulfonate, trifluoromethanesulfonate, p-toluenesulfonate, 10-camphorsulfonate (10-camphorsulfonate). ), Or perfluoro-1-butanesulfonate, R ₁ is a t-butoxycarbonyloxy group, a C ₁ -C ₄ alkyl group and an alkoxy group, R ₂ is hydrogen or a methyl group.)

  The iodonium salt having an anion that generates an organic acid is selected from compounds having the structure of the following formula (s) and used at a ratio of 0.05 to 20 parts by weight with respect to 100 parts by weight of the binder polymer. use.

(In the formula, X is an anion moiety that releases an organic acid, and includes methane sulfonate, trifluoromethanesulfonate, p-toluenesulfonate, 10-camphorsulfonate (10-camphorsulfonate). ), Or perfluoro-1-butanesulfonate, wherein R ₁ and R ₂ are a hydrogen atom, a nitro group, a C ₁ -C ₄ alkyl group, or a C ₁ -C ₄ alkoxy group, respectively. Which may be the same or different.

Japanese Patent Application Laid-Open No. 11-65105 discloses a sulfonium salt having an anion moiety that generates an organic acid of formula (p) and an iodonium salt having an anion moiety that generates an organic acid of formula (s). In comparison with the sulfonium salt and iodonium salt, the sulfonium salt and iodonium salt disclosed in Japanese Patent Application Laid-Open No. 11-65105 generate inorganic acids, whereas the sulfonium salt and iodonium salt of the present invention are not inorganic acids. And a relatively bulky organic acid, which prevents pattern surface hardening and metal contamination, and can be analyzed and tracked by analytical instruments such as ¹ H, ¹³ C NMR. There is an advantage that it is easy.

  The dissolution inhibitor suppresses dissolution of the unexposed area in the developer, and the exposed area promotes dissolution and realizes a positive pattern. However, a t-butoxycarbonyloxy group (t-BOC group) or A benzene compound having an acetal group in the side chain is used in a ratio of 0.05 to 30 parts by weight with respect to 100 parts by weight of the binder polymer.

  The t-BOC group or acetal group is hydrophobic, but is converted to a hydrophilic hydroxyl group by the heat generated by the infrared absorber and the acid generated by the thermal acid generator so that the resist is dissolved in the developer.

  It is particularly useful that the benzene compound having a t-BOC group or an acetal group in the side chain is a compound having a structure of any one of the following formulas (t) to (y).

(In the formula, R represents a t-butoxycarbonyloxy group or a 1-ethoxyethoxy group.)

  As the binder polymer, a novolak resin, a resol resin, a polyvinylphenol resin, and the like are known. However, m-cresol, p-cresol, or a condensation polymer of m- / p-cresol and formaldehyde is used as a gel. A novolak resin having a polystyrene-reduced weight average molecular weight of 1,000 to 15,000 as measured by permeation chromatography (GPC) is preferred.

  The novolak resin preferably has a diazonaphthoquinone substituent having photosensitivity in the side chain, or has a t-butoxycarbonyloxy group or acetal group that is unstable to heat and acid, but the side chain has photosensitivity. As for those having a diazonaphthoquinone substituted product, the hydroxyl group is partially a 2,1-diazonaphthoquinone-5-sulfonyl group or a 2,1-diazonaphthoquinone-4-sulfonyl group Examples of those having a t-butoxycarbonyloxy group or an acetal group include those having a hydroxyl group of 1-ethoxyethoxy group, 1-chloroethoxyethoxy group, tetrahydropyranyloxy group, t-butoxycarbonyl group. Examples thereof include those partially substituted with an oxy group.

  An infrared absorber absorbs infrared rays and generates heat, thereby generating an acid with a thermal acid generator or thermally decomposing a dissolution inhibitor. As the infrared absorber, cyanine dyes, polymethine dyes are used. (Polymethine dye), squarylium dye, croconium dye, pyrylium dye, thiopyrylium dye, and the like are known. The following formulas (1) to (22) show typical examples of infrared absorbing dyes.

  The solvent is not particularly limited as long as it can easily dissolve each component of the photosensitive composition of the present invention and does not lower the physical properties of the photosensitive layer. For example, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol Monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol methyl ether acetate, propylene glycol propyl ether acetate, diethylene glycol dimethyl ether, ethyl lactate, toluene, xylene, methyl ethyl ketone, cyclohexanone, 2-heptanone , 3-heptanone, 4-heptanone or a mixture of these Used at a ratio of 250～3,000 parts by weight relative to the amount unit.

  If necessary, an auxiliary solvent can be used, but the auxiliary solvent is N-methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethyl. Sulfoxide, methanol, ethanol, isobutyl alcohol or a mixture thereof is used in a ratio of 500 to 10,000 parts by weight with respect to 100 parts by weight of the binder polymer.

  In addition, the photosensitive composition of the present invention may contain a dye, a color former, a surfactant, a sensitizer, an adhesion aid, a storage stabilizer, and the like.

  Surfactants include ether compounds such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene nonylphenyl ether, Fluorad FC-4430, FC-4432 (above, manufactured by 3M) ), MEGAFAC R-08, LS-11, F171, 177, 179 (above, manufactured by Dainippon Ink, Inc.), Surfron S-381, S-382, S-383, SC-101, SC-102, SC-103 , SC-104 (above, manufactured by Asahi Glass Co., Ltd.), Eftop EF352, EF301, EF303 [above, made by Shin-Akita Kasei], Schweggerfer 8035, 8036 (above, made by Schwegman), etc. are known. Fluorine compounds are particularly effective , And the use in a proportion of 0.001 to 10 parts by weight relative to the binder polymer 100 parts by weight.

  Sensitizers include anthracene, perylene, phenothiazine, 1,2-benzanthracene, coronene, pyrene, tetracene, acridine Yellow (acridine yellow), acridine orange, benzoflavin, thioxanthone and the like are used in a ratio of 0.01 to 15 parts by weight with respect to 100 parts by weight of the binder polymer.

  In addition, azo compounds, amine compounds and the like are used as adhesion assistants and storage stabilizers.

  The photosensitive composition of the present invention is used after being applied to a support, and the support is plated or vapor-deposited with a metal plate such as aluminum, zinc or copper, or chromium, zinc, copper, nickel, aluminum or iron. Use metal plate, paper, film, glass plate, etc.

  Before applying the photosensitive composition, the support may be subjected to pretreatment such as electrolytic etching, brush graining or anodizing with hydrochloric acid, nitric acid or sulfuric acid aqueous solution.

Application is spin coating, wire-bar coating, dip coating, air-knife coating, roll coating, blade coating, The coating is performed according to a known method such as curtain coating, and the coating amount is suitably 0.5 to 10 g / m ² . After application, the film is dried at 70 to 130 ° C. for 0.5 to 10 minutes.

  For the exposure, a near infrared laser of 650 to 1,300 nm is directly irradiated, and a semiconductor laser, a He—Ne laser, a YAG laser, a carbon dioxide gas laser, or the like is used as a light source.

  Development is carried out using an inorganic or organic aqueous base solution.

  Examples of inorganic alkaline developers include sodium silicate, potassium silicate, lithium silicate, sodium tertiary phosphate, and ammonium secondary secondary. phosphate, sodium metasilicate, sodium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide, lithium hydroxide, etc. were mixed as appropriate Aqueous solutions are known, and organic alkali developers include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanol Ruamin, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, and tri-methyl ammonium hydroxide is known.

  In addition, the inorganic or organic alkaline aqueous solution includes sodium sulfite, potassium sulfite, magnesium sulfite, resorcin, methyl resorcin, hydroquinone, thiosali A cyclic acid (thiosalicyclic acid) etc. may be included.

  In addition, the developer composition may further contain a surfactant and an organic solvent, but the surfactant is preferably a fluorosurfactant as in the case of the photosensitive composition, and the organic solvent is methanol or ethanol. , Isopropanol, ethylene glycol, propylene glycol, ethylene glycol monophenyl ether, benzyl alcohol, n-propyl alcohol and the like are preferably used.

  In particular, for the photosensitive composition of the present invention, among these, a sodium silicate aqueous solution and sodium hydroxide, or a potassium silicate aqueous solution and potassium hydroxide, an inorganic alkaline aqueous solution, and methanol and ethylene glycol as organic solvents. Through a series of experiments, the alkaline aqueous solution to which fluorinated surfactants are added does not leave scum even after development, and the remaining film ratio in the unexposed areas is high. It was revealed.

More specifically, based on 100 parts by weight of the developer, 8.5 to 15 parts by weight of an aqueous sodium silicate solution or an aqueous potassium silicate solution, 1.0 to 3.5 parts by weight of sodium hydroxide or potassium hydroxide, 2.5 to 7.0 parts by weight of ethylene glycol, 0.5 to 3.5 parts by weight of methanol, 0.005 to 1.5 parts by weight of a fluorosurfactant, and the balance is water, and the pH is A developer composition is effective in that it is 10 to 14 and SiO ₂ occupies 0.5 to 6.0 parts by weight as a buffer with respect to 100 parts by weight of the total developer.

  Hereinafter, the present invention will be described in more detail with reference to the following examples. However, these are for illustrating the present invention and do not limit the scope of the present invention.

  Examples 1 to 3 are examples in which a thermal acid generator was synthesized. Examples 4 to 17 were obtained by applying a photosensitive composition to an aluminum substrate, and then exposing and developing to perform the performance of the photosensitive composition, that is, sensitivity. , Resolution, remaining film rate, etc.

[Example 1]
As the thermal acid generator belonging to the above-mentioned formulas (a) to (n), 2,3,4-trihydroxybenzophenone 2-diazo-1-naphthoquinone-4-sulfonate (2-diazo-1-naphthoquinone-4-) sulfonate of 2,3,4-trihydroxybenzophenone) was synthesized.

  2.76 g of 2,3,4-trihydroxybenzophenone and 100 g of pyridine are mixed, and 20.2 g of 2-diazo-1-naphthoquinone-4-sulfonyl chloride is added in a small amount. After dropwise addition, the temperature was raised to 35 ° C. and reacted for 5 hours with stirring. Next, the mixture was cooled to room temperature, filtered to remove the solid, and the filtrate was added dropwise to a mixture of 500 g of ultrapure water and ethanol, whereby a yellow solid was precipitated. The precipitated product was filtered, washed successively with a dilute aqueous hydrochloric acid solution (200 g), ultrapure water (500 g) and ethanol (40 g), and then dried at 45 ° C. for 24 hours.

  A 97.3% pure 2,3,4-trihydroxybenzophenone of 2-diazo-1-naphthoquinone-4-sulfonate was obtained with a yield of 86% relative to the starting material 2,3,4-trihydroxybenzophenone. there were.

[Example 2]
2-diazo-1-naphthoquinone-4-phenyl-sulfonate was synthesized as a thermal acid generator belonging to the above formulas (a) to (n).

To 40 ml of a dichloromethane solution in which 1.05 g of phenol is dissolved, 3.01 g of 2,1-diazonaphthoquinone-4-sulfonyl chloride is mixed. Reacted. Then, the reaction solution was washed with water, the organic layer was dried over Na ₂ SO ₃ and concentrated, and then the obtained crude product was recrystallized with a mixed solvent of dichloromethane and ethanol.

  An orange crystal of 2-diazo-1-naphthoquinone-4-phenyl-sulfonate having a purity of 99.3% was obtained, and the yield based on 2,1-diazonaphthoquinone-4-sulfonyl chloride as a starting material was 81%. .

[Example 3]
As the thermal acid generator belonging to the above formulas (q) and (r), bis [4- (t-butoxycarbonyloxy) phenyl] -3,5-dimethyl-4- (t-butoxycarbonyloxy) phenylsulfonium trif The rate (bis [4- (t-butoxycarbonyloxy) phenyl] -3,5-dimethyl-4- (t-butoxycarbonyloxy) phenyl sulfonium triflate) was synthesized.

  10 g of 4,4-dihydroxyphenyl sulfoxide, 5.2 g of 2,6-dimethylphenol, and 28 g of a mixed solution having a ratio of phosphorus oxide: methanesulfonic acid of 1:10 were reacted at room temperature for 18 hours. Next, the obtained deep purple reaction product was poured into water, 5.04 g of sodium methanesulfonate was added, and the mixture was stirred with water at 40 ° C. As a result, a beige solid was precipitated, but the precipitate was filtered and recrystallized from methanol.

  99% pure bis (4-hydroxyphenyl) -3,5-dimethyl-4-hydroxyphenylsulfonium methanesulfonate (bis (4-hydroxyphenyl) -3,5-dimethyl-4-hydroxyphenyl sulfonium methanesulfonate) is obtained. The yield based on 4,4-dihydroxyphenyl sulfoxide was 70%.

  1 g of bis (4-hydroxyphenyl) -3,5-dimethyl-4-hydroxyphenylsulfonium methanesulfonate is dissolved in 40 ml of tetrahydrofuran (THF), 0.77 g of potassium tert-butoxide and 1.61 g of di-tert-butyl dicarbonate are added. In addition, the reaction was allowed to proceed for 5 hours at room temperature. Next, water was added to stop the reaction, 0.4 g of sodium triflate was added and stirred for 3 hours, and then the product was extracted with methylene chloride, the organic layer was separated, dried and recrystallized with ethanol. did.

  White crystals of bis [4- (t-butoxycarbonyloxy) phenyl] -3,5-dimethyl-4- (t-butoxycarbonyloxy) phenylsulfonium triflate having a purity of 99.3% were obtained and bis (4- The yield based on (hydroxyphenyl) -3,5-dimethyl-4-hydroxyphenylsulfonium methanesulfonate was 81%.

[Example 4]
A. Fabrication of aluminum support 1) Degreasing: Degrease treatment of aluminum plates having thicknesses of 0.24, 0.28, and 0.30 mm, respectively, with a 5 wt% sodium hydroxide aqueous solution at 60 ° C. for 1 minute, washed with water, and 25 The mixture was neutralized with a 10% by weight sulfuric acid aqueous solution at 0 ° C. and then further washed with water.
2) Electropolishing: Electropolishing was performed with a 1.0 wt% nitric acid aqueous solution at a temperature of 25 ° C. and a current density of 10 A / dm ² for 1 minute.
3) Anodizing: Degreasing treatment for 10 seconds with 5% by weight sodium hydroxide aqueous solution at 60 ° C., and anodizing treatment with 20% by weight sulfuric acid aqueous solution for 1 minute at a temperature of 20 ° C. and current density of 3 A / dm ^2. It was. Subsequently, it was immersed in a 1.0 wt% ammonium acetate aqueous solution at 80 ° C. for 30 seconds, washed with water, and then dried at 80 ° C. for 3 minutes.
4) Formation of heat insulating layer: A heat insulating layer was formed by immersing in a 1% by weight carboxymethylcellulose aqueous solution at 80 ° C. for 30 seconds, and dried at 80 ° C. for 5 minutes to complete a support.

B. Production of photosensitive composition As a binder polymer, 3 g of novolak resin ( _Mw = 6,000, m-cresol: p-cresol = 6: 4), which is a cocondensation compound of formaldehyde and m- / p-mixed cresol, 0.06 g of the compound of the formula (4) having p-toluenesulfonate in the anion part as an infrared absorber, 0.09 g of 2-diazo-1-naphthoquinone-4-phenyl-sulfonate as a thermal acid generator, and inhibition of dissolution 2,2-bis [4- (t-butoxycarbonyloxy) phenyl] propane (0.09 g) as a colorant and Victoria Pure 0.09 g of blue (vitoria pure blue) was dissolved in 15 g of propylene glycol monomethyl ether as a solvent.

C. Production of photosensitive plate, exposure, development and results 1) Production of photosensitive plate: The photosensitive composition produced in the step (B) is spin coated on the Ra = 0.55 aluminum substrate produced in the step (A). It was applied and dried in an oven at 105 ° C. for 4 minutes.
2) Exposure: Exposure was performed in a range of 0.35 to 1.0 A using a flat table type continuous wave semiconductor laser (830 nm) system with a 1 W laser part.
3) Development: Development was carried out at 20 ° C. for 20 seconds with a positive CTP developer PT 2G manufactured by Lastra.
4) Results
When scanning irradiation was performed with a laser spot having a size of 30 μm, a high sensitivity and resolution of 30 μm line and space were obtained with a laser intensity of 0.5 A.

[Comparative Examples 1-7]
As the thermal acid generator, instead of 2-diazo-1-naphthoquinone-4-phenyl-sulfonate, the same amount of triphenylsulfonium triflate (Comparative Example 1), bis (cyclohexylsulfonyl) diazomethane (bis (cyclohexylsulfonyl) diazomethane) (Comparative Example 2), o-nitrobenzyl tosylate (Comparative Example 3), bis (phenylsulfonyl) diazomethane (Comparative Example 4), 2- 2-methyl-4,6-bis (trichloromethyl) -s-triazine (Comparative Example 5), 4-methoxyphenyldiphenylsulfonium triflate (4- methoxyphenyl-diphenylsulfonium triflate) (Comparative Example 6) and 1,8-naphthalimidyl triflate (Comparative) Was repeated except for using the 7), it was carried out with the remaining components are the same as in Example 4 to produce the photosensitive composition in the same composition as in Example 4 process.

  The results are shown in Table 1 below. Compared with the results of Example 4, it can be seen that the results of Example 4 are far superior.

[Example 5]
As a thermal acid generator, 0.08 g of 2,3,4-trihydroxybenzophenone 2-diazo-1-naphthoquinone-4-sulfonate and bis [4- (t-butoxycarbonyloxy) phenyl] -3,5-dimethyl Example 4 with the exception that 0.06 g of -4- (t-butoxycarbonyloxy) phenylsulfonium triflate was used, 0.12 g of oil blue II was used as the color former, and 15 g of ethyl cellosolve was used as the solvent. A photosensitive composition having the same composition was produced, applied to the same aluminum substrate as in Example 4 in the same manner, and exposed at 0.8 A intensity using the same laser system (830 nm), and then KPG. Development was performed at 20 ° C. with a CTP positive developer (Goldstar Plus).

  As a result, when continuously oscillating with a 20 μm laser spot, a high resolution pattern of 20 μm line and space is formed with only 3 seconds of development, showing very high sensitivity and resolution, and developing for 10 seconds. In this case, the unexposed portion showed a high residual film ratio of 95%.

[Examples 6 to 9]
Of the components of the thermal acid generator of Example 5, 0.06 g of bis [4- (t-butoxycarbonyloxy) phenyl] -3,5-dimethyl-4- (t-butoxycarbonyloxy) phenylsulfonium triflate was added. 0.06 g of triphenylsulfonium triflate (Example 6), 0.06 g of 4-methoxyphenyldiphenylsulfonium triflate (Example 7), 0.06 g of diphenyliodonium triflate (Example 8), 4-methoxyphenyl- A photosensitive composition was produced with the same composition as in Example 5 except that 0.06 g of phenyliodonium triflate (Example 9) was used, and the same method as in Example 5 was used. I went there.

  As a result, although not reaching the result of Example 5, it is possible to realize a relatively high sensitivity and high resolution of a 30 μm line and a 20 μm space by developing for 10 seconds, and the remaining film ratio of the unexposed portion after development is also different. It was relatively high at 88% (Example 6), 92% (Example 7), 80% (Example 8), and 84% (Example 9).

[Example 10]
7 g of the novolak resin of Example 4 as the binder polymer, 0.14 g of the infrared absorber of Example 4, 0.21 g of the dissolution inhibitor of Example 4, 0.28 g of the color developer Oil Blue II, 2 as the thermal acid generator A photosensitive composition was prepared by dissolving 0.35 g of 2,4-trihydroxybenzophenone 2-diazo-1-naphthoquinone-4-sulfonate in 18 g of ethyl cellosolve.

  The photosensitive composition was spin-coated on an aluminum substrate with Ra = 0.94 μm and Rz = 6.41 μm, dried by the same method as in Example 4, exposed, and then a developer having the composition shown in Table 2 below. And developed at 23 ° C. for 10 seconds.

  As a result, despite the high Ra and Rz values of the aluminum support, it showed high sensitivity and resolving power of 20 μm line and space even under a laser intensity of 0.4 A when irradiated with a 20 μm laser spot. Was also not observed.

[Example 11]
4 g of the same novolak resin as in Example 4, 0.08 g of the same infrared absorber as in Example 4, 0.06 g of the same dissolution inhibitor as in Example 4, 0.08 g of Oil Blue II as the color former, heat As an acid generator, 0.08 g of 2-diazo-1-naphthoquinone-4-phenyl-sulfonate, 0.06 g of tris (4-t-butoxycarbonyloxyphenyl) sulfonium triflate, 0.01 g of a fluorosurfactant, and ethyl cellosolve A photosensitive composition was prepared by dissolving in 15 g.

  The composition was processed in the same manner on the same aluminum substrate as in Example 4, subjected to the same exposure (0.8 A), and dried. Development with KPG CTP positive developer (Goldstar Plus) was carried out at 23 ° C. for 10 seconds.

  As a result, when continuous oscillation was performed with a 20 μm laser spot, high sensitivity and resolution of 20 μm line and space were exhibited, no scum remained, and a high post-development film remaining ratio (95%) was exhibited.

[Examples 12 to 13]
A photosensitive composition obtained by adding 0.06 g of perylene to the same composition as in Example 11 (Example 12), a novolak oligomer of 4,4′-methylenebis {2-[(2-hydroxy-) having a molecular weight of 497 5-methylphenyl) methyl] -3,6-dimethylphenol} (4,4'-methylenebis {2-[(2-hydroxy-5-methylphenyl) methyl] -3,6-dimethylphenol}) Using the photosensitive composition thus obtained (Example 13), coating, drying, exposure and development were carried out in the same manner as in Example 11.

  As a result, a resolution of 20 μm line and space was realized by developing for 5 seconds.

[Example 14]
The remaining components and amounts were the same as in Example 11 except that novolak (M _w = 3,000, dissolution rate = 1000 kg / s) obtained by co-condensing m-cresol with formaldehyde was used as the binder polymer. The same composition and conditions as in Example 11 were used.

  As a result, compared with Example 11, a slight decrease in sensitivity was observed in which the same pattern was not resolved in the same development time.

[Examples 15 to 16]
4 g of the same novolak as in Example 4 as the binder polymer, 0.08 g of the same infrared absorber as in Example 1, 0.16 g of Oil Blue II as the color former, and 2,3,4-trihydroxybenzophenone as the thermal acid generator 0.2 g of 2-diazo-1-naphthoquinone-4-sulfonate, 0.12 g of a compound of the formula (u) having a t-butoxycarbonyloxy group in the side chain as a dissolution inhibitor was dissolved in 15 g of ethyl cellosolve. The photosensitive composition (Example 15) and the same composition as described above, and only the dissolution inhibitor has a structure of the formula (u) having a 1-ethoxyethoxy group (belonging to an acetal group) in the side chain. A photosensitive composition (Example 16) was prepared by changing the compound to 0.12 g, and the same method as in Example 5 was performed.

  As a result, in the two cases, the same results as in Example 5 were shown, but the dissolution inhibitor containing a t-butoxycarbonyloxy group showed a better dissolution inhibition effect.

[Example 17]
0.06 g of the compound of formula (2) was used as an infrared absorber, and the other components and amounts were the same as in Example 4 using the same photosensitive composition as in Example 4.

  As a result, the sensitivity and resolution of 30 μm line and space were shown with a 0.8 A laser.

Claims (11)

Binder polymer that is soluble in alkaline developer, infrared absorber that absorbs infrared rays to generate heat, thermal acid generator that decomposes with heat generated by infrared absorbers to generate acid, and inhibits dissolution in binder polymer In a positive photosensitive composition for a lithographic printing plate comprising a dissolution inhibitor that has an effect but loses dissolution inhibiting power when decomposed by heat or acid, and a solvent,
The thermal acid generator is a 2,1-diazonaphthoquinone-4-sulfonic acid ester derivative, a sulfonium salt having an anion portion that generates an organic acid, an iodonium salt having an anion portion that generates an organic acid, or a mixture thereof. Selected positive photosensitive composition for lithographic printing plate. The positive photosensitive for lithographic printing plates according to claim 1, wherein the 2,1-diazonaphthoquinone-4-sulfonic acid ester derivative is selected from compounds having the structures of the following formulas (a) to (n). Sex composition.

(In the formula, D represents the following formula (o)

It is represented by However, when there are a plurality of D in the structural formula, all of them include, of course, a part of which is D, and when D is not the above formula (o), it is hydrogen. ) The positive photosensitive composition for a lithographic printing plate according to claim 1, wherein the sulfonium salt having an anion that generates an organic acid is selected from compounds having the structure of the following formula (p).

(In the formula, X is an anion moiety that releases an organic acid, and includes methane sulfonate, trifluoromethanesulfonate, p-toluenesulfonate, 10-camphorsulfonate (10-camphorsulfonate). ), Or perfluoro-1-butanesulfonate, and R ₁ , R ₂ , and R ₃ are each a hydrogen atom, a nitro group, a C ₁ -C ₄ alkyl group, or C ₁ -C ₄ alkoxy groups, which may be the same or different.) 2. The positive photosensitive resin for a lithographic printing plate according to claim 1, wherein the sulfonium salt having an anion portion that generates an organic acid is selected from compounds having the structures of the following formulas (q) and (r): Composition.

(In the formula, X is an anion moiety that releases an organic acid, and includes methane sulfonate, trifluoromethanesulfonate, p-toluenesulfonate, 10-camphorsulfonate (10-camphorsulfonate). ), Or perfluoro-1-butanesulfonate, R ₁ is a t-butoxycarbonyloxy group, a C ₁ -C ₄ alkyl group and an alkoxy group, R ₂ is hydrogen or a methyl group.) The positive photosensitive composition for a lithographic printing plate according to claim 1, wherein the iodonium salt having an anion portion that generates an organic acid is selected from compounds having the structure of the following formula (s).

(In the formula, X is an anion moiety that releases an organic acid, and includes methane sulfonate, trifluoromethanesulfonate, p-toluenesulfonate, 10-camphorsulfonate (10-camphorsulfonate). ), Or perfluoro-1-butanesulfonate, wherein R ₁ and R ₂ are a hydrogen atom, a nitro group, a C ₁ -C ₄ alkyl group, or a C ₁ -C ₄ alkoxy group, respectively. Which may be the same or different.   The positive photosensitive composition for lithographic printing plates according to any one of claims 1 to 5, wherein the dissolution inhibitor is selected from benzene compounds containing a t-butoxycarbonyloxy group or an acetal group. 7. The benzene compound having a t-butoxycarbonyloxy group (t-BOC group) or an acetal group in the side chain is selected from compounds having the structures of the following formulas (t) to (y). A positive photosensitive composition for a lithographic printing plate.

(In the formula, R represents a t-butoxycarbonyloxy group or a 1-ethoxyethoxy group.)   The binder polymer is m-cresol, p-cresol, or a condensation polymer of m- / p-cresol and formaldehyde, and the weight average molecular weight in terms of polystyrene by gel permeation chromatography (GPC) measurement is 1, The positive photosensitive composition for lithographic printing plates according to any one of claims 1 to 5, wherein the positive photosensitive composition is selected from 000 to 15,000 novolak resins.   The positive photosensitive composition for a lithographic printing plate according to claim 8, wherein the novolak resin has a diazonaphthoquinone substituted product, a t-butoxycarbonyloxy group or an acetal group in the side chain.   The positive photosensitive composition for lithographic printing plates according to any one of claims 1 to 5, further comprising a fluorine-based surfactant. Based on 100 parts by weight of the developer, 8.5 to 15 parts by weight of an aqueous sodium silicate or potassium silicate solution, 1.0 to 3.5 parts by weight of sodium hydroxide or potassium hydroxide, and 2.5 of ethylene glycol -7.0 parts by weight, 0.5-3.5 parts by weight of methanol, 0.005-1.5 parts by weight of a fluorosurfactant, and the remainder is water, and the pH is 10-14. A developer composition, wherein SiO ₂ occupies 0.5 to 6.0 parts by weight relative to 100 parts by weight of the total developer.