JP2000039705A - Positive lithographic printing master plate using thermosensitive composition and production of printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive lithographic printing master plate excellent in storage stability on which digital image information from a computer can be directly plotted by using high energy light, and to provide a producing method of a printing plate using this master plate. SOLUTION: This positive lithographic printing master plate has a thermosensitive compsn. essentially comprising a material which absorbs light and generates heat, a compd. having one or more basic nitrogen atoms in the molecule, and a novolac resin. The producing method of the positive lithographic printing plate includes a process to expose the printing master plate with high energy light and form an image based on the digital information from a computer, a process to develop the image with an alkali aq. soln., a process of post treatment and a process of burning treatment to produce a printing plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate used in the field of offset printing, and more particularly to a positive lithographic printing plate precursor used as a so-called computer-to-plate (CTP) plate capable of directly making and making a plate from a digital signal by a computer or the like. About.

[0002]

2. Description of the Related Art Conventional plate making systems directly from digital signals of a computer include a system using electrophotography using a visible light laser, a system using exposure and post-processing using a visible light laser, and a system using diffusion transfer of silver salt. Exposure and post-processing using near-infrared to infrared high-power lasers, surface images destroyed by discharge or high-power laser light to obtain printed images, conventional lithographic printing plates with photosensitive image-forming layers There is known a method in which a mask layer is provided on a (PS plate), an image is formed on the mask layer, and a printing plate is obtained through post-processing. At present, each of these methods has advantages and disadvantages, and further study is ongoing.In particular, plate materials using special techniques can be handled in a bright room. By eliminating the image transfer process from film that has been carried out from now on, it is possible to eliminate defects such as blurring and adhesion of dust. In addition, due to the remarkable development of laser light systems in recent years, high-power lasers have become relatively easy to use. Since it is available, it has attracted attention as a realistic plate material because it can obtain a practically sufficient speed during exposure, obtain a high-resolution image, and can handle a large plate.

As a conventional positive-working printing plate precursor using a near-infrared to infrared high-power laser as a light source, Japanese Unexamined Patent Publication (Kokai) No. 7-020629 discloses a plate material that can be used for both positive and negative printing plates. 7-271029, 8-2
No. 2,072,752, and the like, and JP-A-9-171254.
Nos. 9-2111863, 9-21864, 9-21865 and 9-304931 disclose positive printing plate precursors. The technology common to these disclosed documents is composed of a composition comprising at least three types of substances, namely, an alkali water-soluble resin, a substance that absorbs light and generates heat, and a compound that generates an acid by heat. It was a positive printing plate precursor. However, positive printing plate precursors containing these heat-generating compounds often require heat treatment in order to effectively carry out the acid-generating reaction, and heat-generating compounds are easily absorbed by moisture. This causes a problem in the storage stability of the plate material.
In addition, a compound which generates an acid by heat, such as a compound which generates an acid by heat during storage of a printing plate material, is decomposed with time by the action of a novolak resin, causing a problem in storage stability. It was large and had practical problems.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a positive printing plate precursor which can be written with high-density energy light and which does not require a compound which generates an acid by heat which is a factor of storage instability. As a result of the examination,
This was carried out by finding a positive printing plate precursor having excellent storage stability that does not contain a compound that generates an acid by heat.

Accordingly, a first object of the present invention is to make a plate directly from a digital signal from a computer or the like, and to use a conventional processing apparatus for development processing.
An object of the present invention is to provide a positive type lithographic printing plate precursor which is a high density energy optical writing type computer two plate plate which can use a conventional printing apparatus as it is in printing.

A second object of the present invention is to provide a positive type lithographic printing plate precursor produced according to the method of the present invention, which does not require a special safety light and can be operated under ordinary room lighting. Another object of the present invention is to provide a positive lithographic printing plate precursor improved in workability and storage stability, whereby a good printing plate can be produced without any problem.

A third object of the present invention is to efficiently absorb high-density energy light used in the above-mentioned positive type lithographic printing plate precursor and convert it into heat energy, and as a result, a sharp high-resolution latent image is obtained. Is to provide a heat-sensitive composition.

A fourth object of the present invention is to provide a printing plate having a high resolution required for printing by using the positive type lithographic printing plate precursor according to the present invention which has solved the above-mentioned problems. An object of the present invention is to provide a printing plate making method.

[0009]

Means for Solving the Problems A first structure of the present invention for solving the problems is to provide a support having a hydrophilic surface on a support,
A positive-working substance comprising a substance that absorbs light and generates heat, a compound containing at least one basic nitrogen atom in the molecule, and a heat-sensitive composition layer containing a novolak resin as a main component. It is a lithographic printing plate precursor. The second configuration of the present invention is to form a printing plate image by preparing the printing plate precursor and then removing the image portion of the heat-sensitive composition layer by imagewise exposure with high-density energy light by a wet method. To obtain a printing plate through washing, gumming, and drying, and if necessary, performing a burning treatment to obtain a printing plate. "

A first constitution of the present invention is a positive lithographic printing plate precursor wherein the substance that absorbs light and generates heat is a dye containing one or more basic nitrogen atoms in the molecule. . Further, the present invention includes a positive lithographic printing plate precursor wherein the substance that absorbs light and generates heat is a pigment.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is characterized in that a heat-sensitive composition layer having extremely high sensitivity to high-density energy light is coated on a support having a hydrophilic surface. Now, the heat-sensitive composition layer of the present invention will be described in detail.

In the present invention, it is essential that the heat-sensitive composition layer contains a substance which absorbs light and generates heat, and various dyes or pigments can be used as such a substance.

The dyes used in the present invention are dyes containing one or more basic nitrogen atoms in the molecule, and are commercially available dyes and literatures (for example, "Dye Handbook" edited by Organic Synthetic Chemistry Association,
Showa 45, “Color Material Engineering Handbook”, Color Material Association,
Asakura Shoten, 1989, "Technology and Market of Industrial Dyes"
Known ones described in CMC, 1983, "Chemical Handbook, Applied Chemistry", edited by The Chemical Society of Japan, published by Maruzen Shoten, 1986) can be used. Specific examples of the dye containing one or more basic nitrogen atoms in the molecule include an azo dye, a metal chain salt azo dye, a pyrazolone azo dye, an anthraquinone dye, a phthalocyanine dye, a carbonium dye, a quinone imine dye, a methine dye, and a cyanine dye. Dye, indigo dye, quinoline dye, nitro dye, xanthene dye, thiazine dye, azine dye, oxazine dye, stilbene dye, acridine dye, quinoanyl dye, indophenol dye, indoaniline dye, indamine dye, oxidation dye, sulfuration Among dyes such as dyes and reactive dyes, dyes containing a primary, secondary, tertiary or quaternary amine nitrogen atom in the skeleton or side chain in the molecule are exemplified. Among these dyes, those that absorb infrared light or near infrared light are particularly preferred. Dyes that absorb infrared light or near infrared light include, for example, JP-A-58-12524.
No. 6, No. 59-84356, No. 59-202829
Cyanine dyes described in JP-A-58-173696 and JP-A-58-1816.
Methine dyes described in JP-A-58-112595 and JP-A-58-194595;
No. 4793, No. 59-48187, No. 59-7399
Nos. 6, 60-52940, 60-63744, etc .; naphthoquinone dyes described in JP-A-58-11;
No. 2,792, and the like, squarylium dyes described in British Patent No. 434875, cyanine dyes described in US Pat. No. 5,156,938, and near-infrared absorbents. Further, substituted arylbenzo (thio) pyrylium salts described in U.S. Pat. No. 3,881,924, trimethinethiapyrylium salts described in JP-A-57-142645, JP-A-58-181051, and JP-A-58-22014.
No. 3, No. 59-41363, No. 59-84248,
No. 59-84249, No. 59-146063, No. 5
Pyrylium-based compounds described in JP-A-9-146061, cyanine dyes described in JP-A-59-216146, pentamethine thiopyrylium salts described in U.S. Pat. No. 4,283,475, JP-B-5-13514, 19
No. 702, a near-infrared absorbing dye described in U.S. Pat. No. 4,756,993, and the like. Also, many black dyes such as Remazol Black B, Direct Black, Acid Black, Solvent Black, and Oil Black can be used.

The pigment used as a substance that absorbs light and generates heat according to the present invention is commercially available pigment and color index handbook, "Latest Pigment Handbook" (edited by Japan Pigment Technical Association, 19th edition).
1977), “Latest Pigment Application Technology” (CMC Publishing, 19
1986), "Printing Ink Technology" (CMC Publishing, 198)
The pigments described in, for example, 4th year) can be used. Pigment types include black pigment, yellow pigment, orange pigment,
Brown pigment, red pigment, purple pigment, blue pigment, green pigment,
Examples include fluorescent pigments and other polymer-bound dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelated azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments And quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like. Among these specific examples, it generates heat efficiently by absorbing near infrared or infrared lasers,
Moreover, carbon black is preferably used as an economically excellent substance.

These pigments may be used without surface treatment, or may be used after being subjected to a known surface treatment. Examples of the known surface treatment method include a method of surface-coating a resin or wax, and a method of surface activity. Method of attaching the agent, reactive substances (for example, silane coupling agent, epoxy compound,
For example, a method of bonding polyisocyanate) to the surface of the pigment can be considered. These surface treatment methods are described in “Properties and Applications of Metallic Soap” (Koshobo), “Latest Pigment Application Technology” (CMC Publishing, 1986), and “Printing Ink Technology” (CMC Publishing, 1984). ing.
Particularly, a grafted carbon black whose dispersibility in a dispersion solvent is improved by graft polymerization is preferably used in the heat-sensitive composition layer of the present invention.

The grafted carbon black preferably used in the present invention is obtained by polymerizing a vinyl monomer using a polymerization initiator in the presence of carbon black to capture the growing polymer chains formed in the system on the particle surface. It can be synthesized and used by a method of growing a graft chain from a polymerization initiating group introduced to the surface of carbon black, a method of reacting a functional group on the surface of carbon black with a reactive polymer, etc. Grafted carbon black having good dispersibility is commercially available and can be used in the present invention. Regarding these grafted carbon blacks, see “Carbon Black Handbook 3rd Edition, (edited by Carbon Black Association), 1995, 16
7 and "Characteristics and Optimum Blending and Utilization Technology of Carbon Black (Technical Information Association), 1997, p. 111", etc., all of which are suitably used in the present invention.

Specific examples of the grafted carbon black include those obtained by grafting an unsaturated polyester to carbon black and then performing radical polymerization with various vinyl monomers, and those obtained by reacting carbon black with lauroyl peroxide. Radical polymerization reaction product of peroxide group and various vinyl monomers,
Radical polymerization product of azo group-introduced carbon black and various vinyl monomers, cation ring-opening polymer of acylium perchlorate introduced on carbon black and vinyl monomer, lactone, cyclic ether, cyclic acetal, etc., carbon black Ring-opening isomerization polymerization reaction product of chloromethyl group and 2-oxazoline introduced into benzene, cation graft polymerization product of benzylium perchlorate introduced into carbon black with vinyl monomer, lactone, and cyclic ether, carbon Anionic ring-opening polymer of potassium carboxylic acid group and β-propiolactone introduced into black, anionic ring-opening alternating copolymer of potassium carboxylic acid group and epoxide and cyclic acid anhydride introduced into carbon black, carbon black/
Anion graft polymer of butyllithium complex with methyl methacrylate or acrylonitrile, ring-opening polymer of amino group introduced into carbon black and α-amino acid-N-carboxylic anhydride, introduced on the surface of carbon black Highly reactive functional groups, for example, isocyanate group, acyl azide group, acyl chloride group, epoxy group, chlorotriazinyl group, active ester group, etc. and polypropylene glycol, polyethylene glycol, silicon diol, silicon diamine, polyethylene imine, etc. And the like.

The particle size of the pigment used in the present invention is from 0.01 to
Preferably in the range of 15 micrometers,
More preferably, it is in the range of 0.05 to 5 micrometers.

The amount of the dye or pigment used in the present invention is 1 to 50% by weight, more preferably 10 to 30% by weight, based on the total solid content of the heat-sensitive composition layer. When the addition amount is less than 1% by weight, even if it absorbs light and generates heat, the amount of heat does not become sufficient to form an image portion, and when the addition amount is more than 50% by weight, The physical strength of the non-image area is weakened, and sufficient printing durability to be used as a printing plate cannot be obtained.

The compound containing one or more basic nitrogen atoms in the molecule used in the present invention is a compound having at least one primary, secondary, tertiary or quaternary amino group having a molecular weight of 5,000 or less. It is a chain or branched aliphatic compound, alicyclic aliphatic compound, aromatic compound, heterocyclic compound or a salt compound thereof. Further, these compounds may contain hetero atoms such as a sulfur atom, an oxygen atom and a phosphorus atom. Specifically, for example, methylamine, ethylamine, propylamine,
Isopropylamine, 1-butylamine, 2-butylamine, hexylamine, octylamine, decanylamine, eicosanylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, dihexylamine, dioctylamine, didecanylamine, diicosanylamine , Trimethylamine, triethylamine, tripropylamine, tributylamine, trihexylamine, trioctylamine, tridecanylamine, triicosanylamine, tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetrahexyl Ammonium chloride, tetraoctyl ammonium chloride Primary, secondary, tertiary or quaternary alkylamines such as tetradecanyl ammonium chloride and tetraeicosanyl ammonium chloride, ethanolamine, propanolamine, butanolamine, polyoxyethylenylamine, polypropylenylamine, diethanolamine , Dipropanolamine, dibutanolamine, di (polyoxyethylenyl) amine, di (polypropylenyl) amine, triethanolamine, tripropanolamine, tributanolamine, tri (polyoxyethylenyl) amine, tri (polypropylenyl) Primary or secondary or tertiary alkanolamines such as amines, aniline, N-methylanilone, N, N
-Primary, secondary, tertiary or quaternary such as dimethylaniline, diphenylamine, N-methyldiphenylamine, triphenylamine, trimethylphenylammonium chloride
Grade aromatic amines, asparagine, alanine, arginine, isoleucine, glycine, glutamine, tryptophan, threonine, valine, lysine, leucine, cycloleucine, 3-aminopropionic acid, 1-aminobutyric acid, aminovaleric acid, 6-aminocapron Amino acids such as acid, 2-aminocaprylic acid, 9-aminononanoic acid, 10-aminoundecanoic acid, 20-aminoeicosanoic acid and N-substituted compounds thereof, ethylenediamine, trimethylenediamine, tetramethylenediamine, 2, 3-diaminopentane, hexamethylenediamine, piperazine, 2-methylpiperazine, 2,3-diaminocamphane, 1,3-diaminohexane, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,6- Diaminot Ene, 4,6-diamino -2
Amines such as -methylfluoroglucin and its N
-Substituted compounds, pyrrole, pyrroline, pyrrolidine, pyrazole, pyrazoline, pyrazolidine, imidazole,
Oxazole, thiazole, thiadiazole, pyridine, piperazine, pyridazine, pyrimidine, pyrazine,
Heterocyclic compounds such as piperazine, triazine, indole, benzimidazole, purine, quinoline, isoquinoline and the like and N-substituted compounds thereof can be cited, but are not limited thereto.

The amount of the compound containing one or more basic nitrogen atoms in the molecule is added to the heat-sensitive composition in an amount of 0.5 to 50 parts based on 100 parts by weight of the novolak resin. In the case of 0.5 parts or less, the storage stability of the heat-sensitive composition becomes poor, and in the case of 50 parts or more, the balance of dissolution-insoluble in alkali water of the heat-sensitive composition is lost,
It is difficult to maintain good positive lithographic printing plate performance.

The novolak resin used in the present invention is generally and widely sold as a thermosetting resin produced from phenol, m-cresol, 3,5-xylenol, p-alkylphenol, resorcin and the like and formalin using an acid catalyst. You can use what is. Sales companies of this product include Asahi Organic Materials, Toyo Kogyo, Gunei Chemical Lignite, Sumitomo Durez, Dainippon Ink and Chemicals, Mitsubishi Gas Chemical, Hitachi Chemical, Showa Kasei, Toshiba Chemical, Suzuki Chemical, Tatsuo Shokai, etc. Among these products, they can be purchased and used in consideration of the purity, solubility in alkaline water, availability as a printing plate material (ink-inking property, etc.) that can be used for printing plates.

The amount of the novolak resin used in the present invention is desirably 95% by weight or less and 50% by weight or more in the heat-sensitive composition.

In the heat-sensitive composition of the present invention, in addition to the above-mentioned essential three components, a cyclic acid anhydride for increasing the sensitivity, if necessary for the purpose of improving the performance characteristics as a lithographic printing plate,
Immediately after the exposure, a printing-out agent for obtaining a visible image, a dye as an image coloring agent, and other fillers can be added.

Examples of the cyclic acid anhydride include succinic anhydride, glutaric anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, chloromaleic anhydride, trimetic anhydride, Pyromellitic acid and the like are used in the heat-sensitive composition, preferably in an amount of 15% by weight or less.

As a printing-out agent for obtaining a visible image immediately after exposure, a combination of a heat-sensitive compound which releases an acid upon exposure to high-density energy light and an organic dye which forms a salt with an acid and changes color tone is used. Can be mentioned.

Examples of the heat-sensitive compound which can be used in the present invention and release an acid upon exposure to high-density energy light include, for example, latent Bronsted acids disclosed in JP-A-7-20629 and acid precursors described in JP-A-8-220755. No. 9-171254, compounds capable of generating an acid upon irradiation with actinic rays, compounds described in No. 9-211863, compounds capable of generating an acid by heat, actinic rays or radiation according to Nos. 9-212864 and 9-212865 And onium borate complexes according to JP-A-9-304931, and these acid generators are naturally considered to be storage-stable from the viewpoint of the present invention. It is considered to be a cause of instability. Is amount used of less than 5% in the heat-sensitive composition.

Examples of the organic dye capable of forming a salt with an acid generated by heat include a triphenylmethane dye, a cyanine dye, a diazo dye, and a styryl dye. Specific examples include crystal violet, ethyl violet, methyl violet, methylene blue,
Victoria Blue BH, Victoria Pure Blue BO
H, oil blue # 603, malachite green, oil green BG, brilliant green, fuchsin, eosin, rhodamine B, oil pink # 312, oil red 5B, oil black BS, oil yellow # 10
1, phenolphthalein, cresol red, auramine, leuco crystal violet, leucomalachite green, and the like, and the added amount is 15% by weight or less in the heat-sensitive composition.

Further, in the heat-sensitive composition of the present invention, apart from the dye essential for the present invention, as a dye as an image coloring agent, for example, a stilbene dye, a benzophenone dye, a benzoquinone dye, a naphthoquinone dye, a squarylium dye, Dyes which do not necessarily have a basic nitrogen atom in the molecule, such as an oxidation dye, a sulfur dye, a reactive dye, and a fluorescent brightening dye, can also be used. The amount used is 15 in the heat-sensitive composition.
% By weight or less.

Further, in the heat-sensitive composition of the present invention, various resins having a hydrophobic group for improving the ink inking property of an image, such as octylphenol / formaldehyde resin, t-butylphenol / formaldehyde resin, t-butylphenol / formaldehyde resin -Butylphenol-benzaldehyde resin, rosin-modified novolak resin, esters of these modified novolak resins and the like; as additives for improving coating properties, for example, cellulose alkyl ethers,
Ethylene oxide surfactants and the like; fluorine surfactants, specifically, perfluoroalkyl group-containing carboxylate, perfluoroalkyl group-containing sulfonate, perfluoroalkyl group-containing sulfate, perfluoroalkyl group-containing phosphoric acid Anionic fluorine-based surfactants such as salts, amine salts containing perfluoroalkyl groups, cationic fluorine-based surfactants such as quaternary ammonium salts containing perfluoroalkyl groups, carboxybetaines containing perfluoroalkyl groups, perfluoroalkyl groups Amphoteric surfactants such as aminocarboxylates, perfluoroalkyl group-containing oligomers, perfluoroalkyl group-containing polymers, perfluoroalkyl group-containing sulfonamide polyethylene glycol adducts, etc .; improve the flexibility of the coating film As a plasticizer for For example, diethyl phthalate, dioctyl phthalate, butyl glycolate, tricresyl phosphate, dioctyl adipate; known resins added to improve the abrasion resistance of the film include, for example, polyvinyl acetal resin, polyurethane resin, epoxy resin, chloride Vinyl resin, nylon, polyester resin, acrylic resin, etc .; in a range in which the thermal properties of the heat-sensitive composition layer do not change, usually 15% by weight or less, and 40% by weight or less as an additive other than the three main components. can do.

In order to provide the heat-sensitive composition layer of the present invention on a support having a hydrophilic surface, the heat-sensitive composition layer is prepared by applying a coating solution for the heat-sensitive composition layer on a support having a hydrophilic surface and drying. be able to. For the preparation of the heat-sensitive composition layer coating solution,
The respective components of the heat-sensitive composition are dissolved in a solvent capable of dissolving or dispersing, and coated on a support. As the solvent used at this time, methylcellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methanol, ethanol, propanol, butanol, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, acetic acid There are butyl, acetone, dioxane, tetrahydrofuran, cyclohexanone, γ-butyrolactone, toluene, ethylene dichloride, tetrachloroethane, dimethylformamide and the like, and these solvents can be used alone or as a mixture.

The heat-sensitive composition layer coating solution prepared as described above preferably contains 1 to 5 solid components in the coating solution.
After being adjusted to 0% by weight, it is coated on a support having a hydrophilic surface. Coating methods include spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, curtain coating and spray coating, howler coating, spner coating, and doctor knife coating. It is applied to the support by a known coating method such as a method.

As described above, the heat-sensitive composition layer coating solution applied on the support having a hydrophilic surface has a temperature of 30 ° C.
It is dried at 150 ° C. for 10 seconds to 10 minutes using a hot air drier, an infrared drier or the like. The coating amount of the heat-sensitive composition layer after drying is 0.5 to 5.0 g / m ^2. When the coating amount is less than 0.5 g / m ² , the properties as a printing plate are insufficient, and when the coating amount is 5.0 g / m ² or more, it is necessary for image writing with high-density energy light. Heat cannot be obtained.

As the support of the positive type thermosensitive image forming layer of the present invention, for example, a metal plate of aluminum, zinc, copper, stainless steel, iron, etc .; a plastic film of polyethylene terephthalate, polycarbonate, polyvinyl acetal, polyethylene, etc .; A composite material in which a metal layer is provided by a technique such as vacuum evaporation or lamination on paper or a plastic film on which a resin is melt-coated or a synthetic resin solution is coated, and the like can be given. Of these, aluminum and an aluminum-coated composite support are particularly desirable.

The surface of the aluminum support is desirably surface-treated for the purpose of increasing water retention and improving adhesion to the photosensitive layer. For example, as the surface roughening method, a method such as a brush polishing method, a ball polishing method, electrolytic etching, chemical etching, liquid honing, sand plast and the like, and a combination thereof can be mentioned. In particular, a surface roughening method including the use of electrolytic etching is used. preferable.

As the electrolytic bath used in the electrolytic etching, an aqueous solution containing an acid, an alkali or a salt thereof or an aqueous solution containing an organic solvent is used, and among these, particularly, hydrochloric acid, nitric acid or a salt thereof is used. Electrolytes are preferred. Furthermore, the roughened aluminum plate is
If necessary, desmut treatment is performed with an aqueous solution of an acid or an alkali. The aluminum plate thus obtained is desirably subjected to anodic oxidation treatment, particularly desirably a method of treating it in a bath containing sulfuric acid or phosphoric acid.

Also, if necessary, US Pat.
066 and 3,181,461 (sodium silicate, potassium silicate), U.S. Pat. No. 2,946,638, potassium fluorozirconate treatment, U.S. Pat. 201,247, Phosphomolybdate treatment, British Patent 1,108,559
Titanate treatment, German Patent No. 1,099
No. 1,433, polyacrylic acid treatment, German Patent 1,134,093 and British Patent 1,230,447
Polyvinylphosphonic acid treatment described in JP-B-44-6409, phosphinic acid treatment described in JP-B-44-6409, phytic acid treatment described in U.S. Pat. No. 3,307,951, JP-A-58-16893. And JP-A-58-18
No. 291, a treatment with a salt of a hydrophilic organic polymer compound and a divalent metal, and a hydrophilization treatment by undercoating a water-soluble polymer having a sulfonic acid group described in JP-A-59-101651. And those subjected to coloring with an acid dye described in JP-A-60-64352 and silicate electrodeposition described in U.S. Pat. No. 3,658,662.

Further, a material subjected to sealing treatment after graining treatment and anodic oxidation is also preferable. Such a sealing treatment is performed by immersion in hot water and a hot aqueous solution containing an inorganic salt or an organic salt, a steam bath or the like.

Next, a method for producing a printing plate using the positive type lithographic printing plate precursor of the present invention will be described.

The positive planographic printing plate precursor of the present invention can directly write an image on the plate using high-density energy light based on digital image information from a computer or the like.
It is a so-called computer-to-plate (CTP) version. As a high-density energy light source capable of forming an image on the positive type lithographic printing plate precursor of the present invention, various semiconductor lasers having an oscillation wavelength of 300 nm to 950 nm,
Carbon dioxide laser (oscillation wavelength: 10.6 nm), YAG
Laser (oscillation wavelength; 532 nm / 1064 nm), excimer laser (oscillation wavelength: 193 nm / 308 nm
351 nm) argon laser (oscillation wavelength; 488 n)
m), etc., in any case, by selecting an appropriate dye or pigment capable of absorbing a specific wavelength of the light source and converting it into heat from the above-described dyes or pigments, and adding the dye or pigment to the heat-sensitive composition layer. Can be used.

In the heat-sensitive composition layer of the present invention, after an image is written by high-density energy light, an image portion is removed by a development process by a wet method. The developer used at this time is an alkaline aqueous solution containing an alkaline agent.

Specific examples of the alkaline agent in the alkaline aqueous solution used for the developer of the positive-working lithographic printing plate precursor according to the present invention include sodium silicate, potassium silicate, potassium hydroxide, sodium hydroxide, lithium hydroxide, secondary and / or alkaline hydroxides. Sodium or ammonium salts of triphosphoric acid, sodium metasilicate, sodium carbonate, inorganic alkaline agents such as ammonia, mono, di, or trimethylamine, mono, di,
Or organic amine compounds such as triethylamine, mono- or diisopropylamine, n-butylamine, mono-, di- or triethanolamine, mono-, di- or triisopropanolamine, ethyleneimine, ethylenediimine and the like.

The content of these alkaline agents is 0.00
It is 5 to 30% by weight, preferably 0.05 to 15% by weight. When the amount is less than 0.005% by weight, the development becomes poor, and when the amount is more than 30% by weight, adverse effects such as invading a non-image portion used later as a printing plate during development are caused.

An organic solvent may be added to the developer of the positive working lithographic printing plate precursor according to the present invention. Specific examples thereof include ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, and ethylene. Glycol monobutyl acetate, butyl lactate, butyl levulinate, ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone, ethylene glycol monobutyl ether, ethylene glycol benzyl ether, ethylene glycol monophenyl ether, benzyl alcohol, methyl phenyl carbinol, n-amyl alcohol , Methyl amyl alcohol, xylene, methylene dichloride, ethylene dichloride, monochlorobenzene and the like.

The content of these organic solvents is at most 20% by weight, preferably at most 10% by weight.

Further, if necessary, water-soluble sulfites such as lithium sulfite, sodium sulfite, potassium sulfite and magnesium sulfite; alkali-soluble pyrazolone compounds; alkali-soluble thiol compounds; Hard water softeners such as aromatic compounds, polyphosphates and aminopolycarboxylic acids, sodium isopropylnaphthalenesulfonate, sodium n-butylnaphthalenesulfonate, N-methyl-N-
Sodium pentadecylaminoacetate, anionic surfactants such as sodium lauryl sulfate, nonionic surfactants, cationic surfactants, amphoteric surfactants,
Various surfactants such as a fluorine-based surfactant and various defoaming agents can be used.

Regarding the composition of the developer used in the present invention,
The necessary components are selected from the above-mentioned components and used as appropriate. In practice, commercially available developers for negative PS plates or positive PS plates can be used. A commercially available concentrated type positive developer or negative developer can be used in 1 to 2
The one-fold dilution can be used as a developer for the positive working lithographic printing plate precursor according to the present invention.

The conditions for developing the positive type lithographic printing plate precursor according to the present invention are as follows: a temperature of 15 ° C. to 40 ° C. and a time of 1 second to 5 minutes. And then washed with water. If necessary, the surface may be lightly rubbed.

The positive-working lithographic printing plate precursor of the present invention after development is washed with water and / or treated with a water-based desensitizing agent. Examples of the aqueous desensitizing agent include water-soluble natural polymers such as gum arabic, dextrin, and carboxymethyl cellulose; and aqueous solutions of water-soluble synthetic polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylic acid. According to the above, an acid, a surfactant and the like are added to these aqueous desensitizing agents. Then, after desensitization, it is dried and used as a printing plate for printing.

Further, for the purpose of increasing the printing durability of the obtained printing plate, the above printing plate can be burned to form a printing plate. As the burning treatment method, first, the printing plate obtained by the above treatment method is washed with water to remove a rinsing liquid and a gum liquid, and then squeegeeed. Next, an appropriate amount of the surface conditioning liquid is poured onto the plate, and the entire plate is uniformly spread using a special sponge. Squeeze the sponge and wipe off any excess conditioning liquid. The surface conditioning liquid on the plate is dried in a plate dryer. 18 in the burning oven
Burning is performed for 1 minute to 30 minutes under a temperature condition of 0 ° C to 300 ° C. After the plate is cooled, the surface conditioning liquid is removed by washing with water, gummed, dried, and then made into a printing plate.

The surface conditioning liquid used in the present invention is used exclusively as an aqueous solution to be treated before the burning treatment so as not to cause soiling after the burning treatment.
As its main composition, various surfactants, particularly preferably anionic surfactants and / or fluorine-based surfactants, are maintained in the range of 0.005 to 30% by weight, and the pH is maintained in the range of 2 to 11, preferably 3 to 10. For this purpose, various acids, alkalis or salts are added. Preferred specific examples of the anionic surfactant include sulfonic acids such as alkyl benzene sulfonate, alkyl diphenyl ether disulfonate, alkyl naphthalene sulfonate, aldehyde condensate of alkyl naphthalene sulfonate, α-olefin sulfonate and alkyl sulfonate. Group-containing activators, sulfate ester activators such as lauryl sulfate, polyoxyethylene alkyl ether sulfate, and polyoxyethylene alkyl phenyl ether sulfate can be exemplified. Specific examples of the fluorine-based surfactant include a perfluoroalkyl group-containing carboxylate, a perfluoroalkyl group-containing sulfonate, a perfluoroalkyl group-containing sulfate, and a perfluoroalkyl group-containing phosphate. Fluorine-based surfactant,
Cationic fluorosurfactants such as perfluoroalkyl group-containing amine salts and perfluoroalkyl group-containing quaternary ammonium salts, amphoteric fluorine interfaces such as perfluoroalkyl group-containing carboxybetaines and perfluoroalkyl group-containing aminocarboxylates Examples of the surfactant include a surfactant, a perfluoroalkyl group-containing oligomer, a perfluoroalkyl group-containing polymer, and a nonionic fluorine-based surfactant such as a perfluoroalkyl group-containing sulfonamide polyethylene glycol adduct. Also, as the acid, nitric acid,
Examples thereof include mineral acids such as sulfuric acid and phosphoric acid, citric acid, succinic acid, oxalic acid, tartaric acid, acetic acid, malic acid, phytic acid, organic phosphonic acid, p-toluenesulfonic acid, and xylenesulfonic acid. In addition, potassium, lithium, sodium, and ammonium salts of these acids, and hydroxides, carbonates, and hydrogencarbonates of alkali metals can be given.

Further, in the surface conditioning liquid of the present invention, a polymer compound having a film-forming ability, which is a natural product, a modified product of a natural product or a synthetic polymer, is added in an amount of 0.00% based on the total weight.
It can be added in an amount of from 01% by weight to 3% by weight. Further, a preservative, an antifoaming agent, a coloring agent and the like can be added.

As a preferred method for producing a good printing plate using the positive type lithographic printing plate precursor according to the present invention, first, the positive type lithographic printing plate precursor according to the present invention is prepared using YAG
It is to be mounted on an image exposure machine using a high-density energy light such as a laser or an infrared semiconductor laser as a light source, and to directly write digital information from a computer on the positive type lithographic printing plate precursor of the present invention. At this time, the positive type lithographic printing plate precursor according to the present invention has a feature that, in handling before and after exposure, no special safety light is required and the work can be normally performed under room light.

Next, a developing process is performed using a developer obtained by diluting a commercially available developer for a positive or negative PS plate to remove an image portion.

The developing conditions at this time may be usually the same as the developing conditions for a negative or positive PS plate generally used in the market.

Thereafter, the plate is washed with water and / or treated with an aqueous desensitizing agent and then dried to obtain a printing plate.

The above development processing steps may be carried out one by one, but practically, the use of an automatic developing machine capable of performing these operations consistently makes the operation steps easy. preferable.

Further, the printing plate according to the present invention can be subjected to a burning treatment for increasing printing durability and then subjected to printing.

[0059]

Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1 An aluminum plate having a thickness of 0.3 mm was grained with a nylon brush and an aqueous suspension of 400 mesh pumistone, and the surface thereof was grained.
Anodizing treatment was performed at a current density of 2 A / dm ² in a ² % sulfuric acid electrolytic solution to form an oxide film of 2.7 g / m ² , which was washed with water and dried to obtain a support.

Novolak resin (ZH8011; manufactured by Dainippon Ink and Chemicals, Inc.) 9.0 in a mixed solvent consisting of 60.0 g of methyl ethyl ketone and 40.0 g of methyl cellosolve 9.0
g of the dye IR830A.
(Infrared dye containing one tertiary amine nitrogen atom and one quaternary amine nitrogen atom in the molecule; ADS, USA)
0.8 g and oil black 2HB (a dye having absorption in the infrared region containing a plurality of basic nitrogen atoms in the molecule;
(Tokyo Kasei) 0.2 g was added and dissolved by stirring. Finally, 1.0 g of triethanolamine as a compound containing a basic nitrogen atom in the molecule was added and stirred to dissolve uniformly, followed by filtration through a 15-micrometer filter to obtain a coating solution.

The above coating solution was coated on the above-mentioned support using a wire bar having a rod number of # 16, dried at 105 ° C. for 3 minutes, and the positive type lithographic printing plate precursor number (1) of the present invention was obtained.
I got The dry coating amount was 2.2 g / m ² .

Next, a positive-working lithographic printing plate precursor of Reference Example 1 was obtained by exactly the same operation and addition compound except that triethanolamine which is a compound containing a basic nitrogen atom in a molecule was not added. The dry coating amount was 2.1 g / m ² .

The obtained invention (1) and reference example (1)
Of the positive type lithographic printing plate precursor in a hydro oven (temperature 6
(0 ° C., humidity 75%) for 5 hours and 15 hours to perform a time-dependent change acceleration test.

A test exposure machine equipped with a 1 W infrared semiconductor laser (wavelength 808 nm, exposure energy 230 mJ / cm ² ; manufactured by Line Electronics Co., Ltd.)
After performing image exposure in, a positive PS plate developer PD-1
Using a dilute solution (manufactured by Polychrome Japan), development was carried out by hand development at 30 ° C. for 30 seconds. At that time, the developer PD
By changing the dilution degree of -1, the dilution point at which the obtained image was the sharpest was taken as an appropriate point. Table 1 shows the appropriate points of each sample.

[0066]

[Table 1] Appropriate points (P
D-1 dilution)

As is clear from the results shown in Table 1, in the case of the positive type lithographic printing plate precursor No. (1) according to the present invention, even when the aging change acceleration test using a hydro oven was performed, the appropriate point of the developing solution changed. do not do. On the other hand, in Reference Example 1 which does not satisfy the requirements of the present invention, a change due to the hydro-oven occurs and the appropriate point shifts, and it is impossible to develop a sample for the accelerated change test with the same developer to obtain the appropriate point. From the above, it can be seen that the positive type lithographic printing plate precursor according to the present invention is a positive type lithographic printing plate precursor excellent in storage stability as compared with the reference example.

(Example 2) A test exposure machine (wavelength 808n) equipped with a 1W infrared semiconductor laser mounted on the positive type lithographic printing plate precursor number (1) according to the present invention prepared in Example 1
m, exposure energy amount 230 mJ / cm ² ; manufactured by Line Electronics Co., Ltd.), and then a positive PS plate developer P
30 ° C. using an automatic developing machine PD-1312-M (manufactured by Dainippon Screen) filled with a 1: 5 diluted solution of D-1 (manufactured by Polychrome Japan) and a gum solution UG1 (manufactured by Polychrome Japan). After 12 seconds of development, gumming and drying, a printing plate (1) was obtained. The above printing plate manufacturing processes were all performed in a light room.

Separately, the printing plate (1) was washed with water and treated with a surface-regulating solution (UT1; manufactured by Polychrome Japan), and then placed in a burning oven (SPBO-1 type; manufactured by Koyo Chemical) at 240 ° C. for 10 minutes. Burning, washing and gumming were performed to prepare a printing plate (1 ′).

Next, a printing test was performed using the printing plates (1) and (1 ′). The printing conditions are as follows;
OKO 820L "(manufactured by Tokyo Airlines Keiki Co., Ltd.), printing speed 5000 sheets / hour, printing paper; Jujo Diamond Coat B
4. Ink: Geos-G-Red-S (manufactured by Dainippon Ink and Chemicals), etch solution: "PP Screen" (manufactured by Niken Kagaku Kenkyusho) dampening solution; PP screen diluted with water 1:50 used. The good number of copies of the printed image is the printing plate (1)
Was 20,000 sheets, and in the case of the printing plate (1 ′), 43,000 sheets.

Example 3 Methyl ethyl ketone 60.0
5.8 g of a novolak resin ZH8011 (manufactured by Dainippon Ink and Chemicals) and a novolak resin ZH8050 in a mixed solvent consisting of
Dissolve 3.2 g (manufactured by Dainippon Ink and Chemicals), and add 1.0 g of oil black 2HB (a dye having a plurality of basic nitrogen atoms in the molecule and having absorption in the infrared region; Tokyo Kasei) and a base in the molecule. Ethylenediamine polypropylene oxide adduct EDP as a compound containing a neutral nitrogen atom
After adding 1.0 g of -300 (manufactured by Adeka Argus Chemical Co., Ltd.) to make a uniform solution, the solution was filtered through a 15-micrometer filter to obtain a coating solution.

The above coating solution was coated on the support prepared in Example 1 using a wire bar having a rod number of # 16, dried at 105 ° C. for 3 minutes, and dried at 105 ° C. for a positive lithographic printing plate precursor according to the present invention. (2) was obtained. The dry coating amount is 2.2 g / m ²
Met.

The positive type lithographic printing plate precursor number 2 according to the present invention
A test exposure machine equipped with a 1 W infrared semiconductor laser (wavelength 808 nm, exposure energy 230 mJ / cm
² ; made by Line Electronics Co., Ltd.), and a 1: 6 diluted solution of a positive PS plate developer PD-1 (manufactured by Polychrome Japan) and a gum solution UG1 (manufactured by Polychrome Japan) were used. Automatic developing machine PD-1312-M filled
Using (Dai Nippon Screen Co., Ltd.), development was performed at 30 ° C. for 12 seconds, gum treatment and drying were performed to obtain a printing plate (2). The above printing plate manufacturing processes were all performed in a light room.

Separately, the printing plate (2) was washed with water, treated with a surface-regulating solution (UT1; manufactured by Polychrome Japan), and then placed in a burning oven (SPBO-1 type; manufactured by Koyo Chemical) at 240 ° C. for 10 minutes. Burning, washing and gumming were performed to prepare a printing plate (2 ′).

Next, a printing test was performed using the printing plates (2) and (2 ′). The printing conditions are as follows;
OKO 820L "(manufactured by Tokyo Airlines Keiki Co., Ltd.), printing speed 5000 sheets / hour, printing paper; Jujo Diamond Coat B
4. Ink: Geos-G-Red-S (manufactured by Dainippon Ink and Chemicals), etch solution: "PP Screen" (manufactured by Niken Kagaku Kenkyusho) dampening solution; PP screen diluted with water 1:50 used. The good number of copies of the printed image is the printing plate (2)
Was 25,000, and in the case of the printing plate (2 '), 50,000.

Example 4 Methyl ethyl ketone 60.0
g and 10.0 g of 1-propanol, 1.5 g of carbon black CWA (carbon black grafted with an acrylic acid resin; manufactured by Ciba Geigy) powder was added thereto, and a homogenizer HG30 (Hitachi, Ltd.) equipped with a cutter C20 was added. (Manufactured by Seisakusho Co., Ltd.) for 10 minutes, and then filtered through a 15-micrometer filter to obtain a carbon black CWA dispersion. This dispersion contained 1.2% by weight of solids. Next, 9.0 g of novolak resin ZH8011 (manufactured by Dainippon Ink and Chemicals, Ltd.) was dissolved in this dispersion, and 1.0 g of triethanolamine was further added to form a uniform dispersion, which was then filtered through a 15-micrometer filter. To obtain a coating solution.

The above-mentioned coating solution was applied to the support prepared in Example 1 using a wire bar having a rod number of # 16, dried at 80 ° C. for 3 minutes, and dried under a positive lithographic printing plate precursor according to the present invention. (3) was obtained. The dry coating amount was 2.3 g / m ² .

The positive type lithographic printing plate precursor number according to the present invention
(3) Test equipped with 1W infrared semiconductor laser
Exposure machine (wavelength 808 nm, exposure energy 230 mJ
/ Cm ^Two; Made by Line Electronics Co., Ltd.)
Positive PS plate developer PD-1 (Polychrome Japan)
1:12 dilution solution and gum solution UG1 (Polychrome)
Developed PD-131
Using 2-M (manufactured by Dainippon Screen) at 30 ° C., 12
Developing for 2 seconds, gumming and drying, printing plate (3)
I got The above printing plate manufacturing processes were all performed in a light room.

Separately, the printing plate 3 is washed with water,
T1; Polychrome Japan Co., Ltd.), and then treated in a burning oven (SPBO-1 type; Koyo Chemical).
Burning was performed at 0 ° C. for 10 minutes, followed by washing with water and gumming to prepare a printing plate (3 ′).

Next, a printing test was performed using the printing plates (3) and (3 '). The printing conditions are as follows;
OKO 820L "(manufactured by Tokyo Airlines Keiki Co., Ltd.), printing speed 5000 sheets / hour, printing paper; Jujo Diamond Coat B
4. Ink: Geos-G-Red-S (manufactured by Dainippon Ink and Chemicals), etch solution: "PP Screen" (manufactured by Niken Kagaku Kenkyusho) dampening solution; PP screen diluted with water 1:50 used. The good number of copies of the printed image is the printing plate (3)
In the case of the printing plate (3 '), it was 20,000 sheets.

[0081]

According to the present invention, a pigment or a dye containing at least one or more basic nitrogen atoms is used as a substance which absorbs light and generates heat, and a compound containing at least one or more basic nitrogen atoms and a novolak resin are heat-sensitive. The positive-working lithographic printing plate precursor according to the present invention coated on a support having a hydrophilic surface as a main component of the hydrophilic composition has good storage stability and is exposed to high-energy light based on digital information from a computer. By performing image-wise exposure, development with an aqueous alkali solution, post-treatment, and, if necessary, processing such as burning, a printing plate from which a good printed matter was obtained could be produced.

Continued on the front page F term (reference) 2H025 AA00 AB03 AC08 AD03 CB29 CC20 EA01 FA28 FA29 2H096 AA07 AA08 BA16 BA20 CA03 EA02 EA04 GA08 GA09 GA17 HA01 HA02 JA04 JA10 2H114 AA04 AA14 AA22 BA01 BA06 DA29 GA05 GA38

Claims (5)

[Claims] 1. A heat-sensitive composition containing a substance that absorbs light and generates heat, a compound containing at least one basic nitrogen atom in a molecule, and a novolak resin on a support having a hydrophilic surface. A positive-working lithographic printing plate precursor comprising a material layer. 2. The positive lithographic printing plate according to claim 1, wherein the substance that absorbs light and generates heat according to claim 1 is a dye containing at least one basic nitrogen atom in a molecule. Original version. 3. The positive lithographic printing plate precursor according to claim 1, wherein the substance that absorbs light and generates heat according to claim 1 is a pigment. 4. An imagewise exposing step of the positive type lithographic printing plate precursor according to claim 1 using high density energy light,
A lithographic printing plate, characterized in that a printing plate is obtained through a process of forming a printing plate image by removing an image portion of the heat-sensitive composition layer by a wet method, a washing process, a gumming process, and a drying process. Plate making method. 5. A method for preparing a lithographic printing plate, comprising subjecting the printing plate of claim 4 to a burning process.