JP2003145955A - Heat-sensitive lithographic printing plate master - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-sensitive lithographic printing plate master which has excellent sensitivity, plate cleaner resistance and plate wear resistance, which is mounted directly in a printer and printed without treating simultaneously and in which scumming hardly occurs. SOLUTION: The heat-sensitive lithographic printing plate master comprises (1) an ink acceptive layer containing two or more types of polymers having different weight-average molecular weights and a photothermal conversion agent, and (2) a hydrophilic layer coating with a solution containing the colloid of an oxide or a hydroxide of at least one element selected from the group consisting of beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony and a transition metal, sequentially provided in this order, on a support.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive lithographic printing plate precursor which does not require development, is excellent in printing durability and stain resistance, and is excellent in sensitivity and plate cleaner resistance. More specifically, it is possible to record an image by infrared or near-infrared laser beam scanning exposure based on a digital signal, and the image-recorded product is mounted on a printing machine as it is and printed without going through a conventional developing process. The present invention relates to a lithographic printing plate precursor that can be used.

[0002]

2. Description of the Related Art Various methods have been proposed for a lithographic printing plate precursor which is image-formed by heat and which can be mounted on a printing machine without treatment. One of the promising methods is an ablation method in which a solid high-power infrared laser such as a semiconductor laser or a YAG laser is used for exposure, and the exposed portion is heated by a photothermal conversion agent to cause decomposition and evaporation. That is, it is a method in which a hydrophilic layer is provided on a lipophilic substrate or a substrate having an lipophilic layer, and the hydrophilic layer is image-wise ablated and removed.

[0004] WO94 / 18005 discloses a printing plate in which a crosslinked hydrophilic layer is provided on an lipophilic laser light absorbing layer and the hydrophilic layer is ablated. This hydrophilic layer is made by cross-linking polyvinyl alcohol with a hydrolyzate of tetraethoxysilicon and contains titanium dioxide particles, and is intended to improve the film strength of the hydrophilic layer. Printing durability is improved by this technique. However, although polyvinyl alcohol has a hydrocarbon group and is not necessarily highly hydrophilic, it occupies 48% by mass of the solid content of the hydrophilic layer. Therefore, it is insufficient in stain resistance and needs further improvement.

WO98 / 40212, WO99 /
In JP 19143 and WO 99/19144, a hydrophilic layer whose main component is a colloid such as silica crosslinked with a crosslinking agent such as aminopropyltriethoxysilane is provided on a substrate coated with an ink receiving layer, A lithographic printing plate precursor that can be mounted on a printing machine without development is disclosed. This hydrophilic layer has as few hydrocarbon groups as possible to enhance the resistance to printing stains, and improves the printing durability by crosslinking the colloid with a crosslinking agent. However, its printing durability is inadequate to several thousand sheets.

A digital direct unprocessed printing plate utilizing ablation can directly make a printing plate from below the plate without interposing a film, and can be mounted on a printing machine as it is for immediate printing. There is a big advantage of rationalization of waste and reduction of waste, but due to the difficulty of the technology without processing, either the stain resistance or printing durability, which is the basis of printing, tends to be impaired, and a technology that achieves both Can be said to be still under development. In the course of such technological development process, JP-A-2001-96938
Japanese Patent Publication No. a) on an ink receiving layer containing a photothermal conversion agent, b) selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony and transition metals. By installing a hydrophilic layer formed by applying a solution containing a colloid of at least one element oxide or hydroxide and a hydrophilic resin, printing is performed by directly mounting it on a printing machine without processing. A heat-sensitive lithographic printing plate precursor is disclosed which has excellent printing durability and does not easily cause printing stains. However, this heat-sensitive lithographic printing plate has not been able to satisfy both the sensitivity and the plate cleaner resistance.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to overcome the above-mentioned drawbacks of the prior art and to be excellent in sensitivity and plate cleaner resistance, and at the same time, to be directly mounted on a printing press without performing processing for printing. It is possible to provide a heat-sensitive lithographic printing plate precursor having excellent printing durability and less likely to cause printing stains.

[0007]

In order to overcome the above-mentioned drawbacks of the prior art, the present inventor has conducted earnest studies and, as a result, devised the composition of the polymer forming the ink receiving layer to improve the sensitivity and the plate. The present invention has been completed by finding that both cleaner resistance can be achieved. That is, the present invention is as follows.

1. On a support, a) an ink receiving layer containing two abnormal polymers having different weight average molecular weights and a photothermal conversion agent, b) beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, A heat-sensitive lithographic printing plate precursor comprising a hydrophilic layer formed in this order by coating a solution containing a colloid of an oxide or hydroxide of at least one element selected from vanadium, antimony and a transition metal.

2. The two abnormal polymers having different weight average molecular weights have at least a weight average molecular weight of 500 to 3
000 low molecular weight polymer and weight average molecular weight 3000 to
The heat-sensitive lithographic printing plate precursor as described in 1 above, which is composed of 100,000 high molecular weight polymer.

In the polymer forming the ink receiving layer of the heat-sensitive lithographic printing plate precursor of the present invention, the low molecular weight polymer has high ablation property and high sensitivity, but has poor plate cleaner resistance. On the other hand, high molecular polymers have low ablation properties and low sensitivity, but have excellent plate cleaner resistance. Since the ink receiving layer of the present invention contains two or more of these low molecular weight polymers and high molecular weight polymers, both sensitivity and plate cleaner resistance can be achieved.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. The ink receiving layer of the present invention is obtained by coating the surface of a support with a coating liquid containing a lipophilic film-forming polymer and a photothermal conversion agent as main components. The polymer needs to be soluble in the coating solvent of the ink receiving layer, but is preferably insoluble in the coating solvent of the upper hydrophilic layer described later. However, it may be desirable that the one partially swelling in the coating solvent of the upper layer has excellent adhesiveness to the upper layer. In addition, when a polymer soluble in the coating solvent for the upper layer is used, it is desirable to cure the polymer by adding a crosslinking agent in advance.

As described above, it is necessary to select two or more polymers having different weight average molecular weights as the polymer constituting the ink receiving layer of the present invention. By blending a low molecular weight polymer having high ablation properties and high sensitivity with a high molecular weight polymer having excellent plate cleaner resistance, a polymer having well-balanced ablation properties, sensitivity and plate cleaner resistance can be obtained. Preferably, a low molecular weight polymer having a weight average molecular weight of 500 to 3000 and a high molecular weight polymer having a weight average molecular weight of 3000 to 100000 are blended, and the composition ratio is by weight, and the low molecular weight polymer / high molecular weight polymer is 5/95. ~ 50 /
50, more preferably 10/90 to 40/60. As the polymer constituting the ink receiving layer, a polymer having 100% of the above composition is preferable, but it goes without saying that a polymer having a higher molecular weight may be blended therein as long as the above characteristics are not impaired.

Polymers useful in the present invention include:
Polyester, polyurethane, polyurea, polyimide, polysiloxane, polycarbonate, phenoxy resin, epoxy resin, phenol / formaldehyde resin, alkylphenol / formaldehyde resin, polyvinyl acetate, acrylic resin and its copolymers, polyvinylphenol, polyvinylhalogenated phenol, methacrylic resin And copolymers thereof, acrylamide copolymers, methacrylamide copolymers, polyvinyl formal, polyamides, polyvinyl butyral, polystyrene, cellulose ester resins, polyvinyl chloride and polyvinylidene chloride. Among these, as a more preferable compound, a hydroxy group on the side chain,
A resin having a carboxy group, an epoxy group, a sulfonamide group, or a trialkoxysilyl group is desirable because it has excellent adhesiveness to a substrate or an upper hydrophilic layer and is easily cured with a crosslinking agent in some cases. Others, acrylonitrile copolymer,
Polyurethane, a copolymer having a sulfonamide group in the side chain or a copolymer having a hydroxy group in the side chain that is photocured with a diazo resin is preferable.

Other phenols, cresol (m-cresol, p-cresol, m / p mixed cresol), phenol / cresol (m-cresol, p-cresol, m / p mixed cresol), phenol-modified xylene, tert-butylphenol, Novolac resin and resol resin of condensation with formaldehyde such as octylphenol, resorcinol, pyrogallol, catechol, chlorophenol (m-Cl, p-Cl), bromophenol (m-Br, p-Br), salicylic acid, phloroglucinol and the like, Further, a condensation resin of the above phenol compound and acetone is useful.

Other suitable polymer compounds include copolymers containing the monomers shown in the following (1) to (12) as their constituent units. (1) Acrylamides having an aromatic hydroxy group,
Methacrylamides, acrylic esters, methacrylic esters and hydroxystyrenes such as N
-(4-hydroxyphenyl) acrylamide or N
-(4-hydroxyphenyl) methacrylamide, o
-, M- and p-hydroxystyrene, o-, m- and p-hydroxyphenyl acrylate or methacrylate, (2) acrylic acid esters and methacrylic acid esters having an aliphatic hydroxy group, for example,
2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate,

(3) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, cyclohexyl acrylate, octyl acrylate, phenyl acrylate, benzyl acrylate, acrylate-2 -(Substituted) acrylic acid esters such as chloroethyl, 4-hydroxybutyl acrylate, glycidyl acrylate, N-dimethylaminoethyl acrylate, (4) methyl methacrylate,
Ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, octyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, 4-hydroxybutyl methacrylate, (Substituted) methacrylic acid esters such as glycidyl methacrylate and N-dimethylaminoethyl methacrylate,

(5) Acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-ethylacrylamide, N-ethylmethacrylamide, N-hexylacrylamide, N
-Hexyl methacrylamide, N-cyclohexyl acrylamide, N-cyclohexyl methacrylamide, N
-Hydroxyethyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N
-Phenylmethacrylamide, N-benzylacrylamide, N-benzylmethacrylamide, N-nitrophenylacrylamide, N-nitrophenylmethacrylamide, N-ethyl-N-phenylacrylamide and N-ethyl-N-phenylmethacrylamide. Alternatively, methacrylamide, (6) ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether,
Vinyl ethers such as phenyl vinyl ether,

(7) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate, (8) styrenes such as styrene, methyl styrene and chloromethyl styrene, (9) methyl vinyl ketone, ethyl Vinyl ketones such as vinyl ketone, propyl vinyl ketone, phenyl vinyl ketone, (1
0) olefins such as ethylene, propylene, isobutylene, butadiene, isoprene, (11) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile, etc.,

(12) N- (o-aminosulfonylphenyl) acrylamide, N- (m-aminosulfonylphenyl) acrylamide, N- (p-aminosulfonylphenyl) acrylamide, N- [1- (3-aminosulfonyl)) Naphtyl] acrylamide, acrylamides such as N- (2-aminosulfonylethyl) acrylamide, N- (o-aminosulfonylphenyl) methacrylamide, N- (m-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonyl) Methacrylamides such as phenyl) methacrylamide, N- [1- (3-aminosulfonyl) naphthyl] methacrylamide, N- (2-aminosulfonylethyl) methacrylamide, and o-aminosulfonylphenyl acrylate, m-amino. Sulfo sulfonyl phenyl acrylate,
p-aminosulfonylphenyl acrylate, 1- (3
-Aminosulfonylphenylnaphthyl) acrylates and other unsaturated sulfonamides such as acrylic acid esters, o-aminosulfonylphenyl methacrylate, m
-Unsaturated sulfonamides such as methacrylic acid esters such as aminosulfonylphenyl methacrylate, p-aminosulfonylphenyl methacrylate, 1- (3-aminosulfonylphenylnaphthyl) methacrylate.

The photothermal conversion agent contained in the ink receiving layer of the present invention for increasing the heat sensitivity is 700 to 120.
Any substance that absorbs 0 nm light can be used, and various pigments and dyes can be used. As pigments, commercially available pigments and color index (CI) handbook, "Latest pigment handbook" (edited by Japan Pigment Technology Association, published in 1977), "Latest pigment application technology" (CMC Publishing, published in 1986), "Printing" The pigments described in "Ink Technology" (CMC Publishing, 1984) can be used.

Examples of pigments include black pigments, brown pigments, red pigments, violet pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments. , Quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black and the like can be used.

These pigments may be used without being surface-treated, or may be used after being surface-treated in order to improve the affinity with a polymer having a lipophilic film-forming ability. The surface treatment method includes a method of surface-coating a lipophilic resin, a method of attaching a surfactant, and a reactive substance (for example, silica sol, alumina sol, silane coupling agent, epoxy compound, isocyanate compound, etc.) to the pigment surface. There is a method of binding, etc., and "property and application of metal soap" (Koshobo), "printing ink technology" (CMC Publishing, 1984) and "latest pigment application technology" (CMC Publishing, 1986).
Annual publication).

Among these pigments, those that absorb infrared rays or near infrared rays are preferable because they are suitable for use in lasers that emit infrared rays or near infrared rays. A particularly preferred pigment is carbon black.

As the dye, commercially available dyes and known dyes described in the literature (for example, "Dye Handbook" edited by The Society of Organic Synthetic Chemistry, published in 1970) can be used. Specific examples include dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, and cyanine dyes. Among these dyes, those that absorb infrared light or near infrared light are particularly preferable because they are suitable for use in a laser emitting infrared light or near infrared light.

Examples of dyes that absorb infrared rays or near infrared rays include JP-A-58-125246 and JP-A-59-8.
4356, cyanine dyes described in JP-A-60-78787 and the like, methine dyes described in JP-A-58-173696, JP-A-58-181690 and JP-A-58-194595. JP-A-58-1127
93, JP-A-58-224793, and JP-A-59-4.
8187, JP-A-59-73996, JP-A-60-
No. 52940, naphthoquinone dyes described in JP-A-60-63744, etc., squarylium dyes described in JP-A-58-112792, UK Patent 43
Cyanine dye described in US Pat. No. 4,875
6,993 dyes, U.S. Pat. No. 4,973,57
The cyanine dyes described in No. 2 and the dyes described in JP-A No. 10-268512 can be mentioned.

Also, as a dye, US Pat. No. 5,156,
The near-infrared absorption sensitizer described in US Pat. No. 938 is also preferably used, and the substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, JP-A-57-1.
No. 42645 (US Pat. No. 4,327,169), a trimethine thiapyrylium salt, JP-A-58-1810.
No. 51, No. 58-220143, No. 59-41363.
No. 59-84248, No. 59-84249, No. 59-146063, No. 59-146061, and the pyrylium compounds described in JP-A-59-2161.
46, cyanine dyes, US Pat. No. 4,283,4
No. 75 pentamethine thiopyrylium salt, etc., and the pyrylium compounds disclosed in Japanese Examined Patent Publication Nos. 5-13514 and 5-19702, Epolig manufactured by Eporin.
ht III-178, Epolyt III-130, E
Polyit III-125 and the like are also preferably used.
Among these dyes, particularly preferred specific examples are listed below by structural formulas.

[0027]

[Chemical 1]

[0028]

[Chemical 2]

[0029]

[Chemical 3]

[0030]

[Chemical 4]

The proportion of the photothermal conversion agent added to the ink receiving layer is preferably 1 to 40% by weight of the total amount of the ink receiving layer, and particularly preferably 20 to 35% by weight for pigments and 5 to 20 for dyes. It is% by mass. If the addition amount of the pigment or dye is less than the above range, the sensitivity will decrease, and if it is more than the above range, the durability of the layer will decrease.

In addition to the polymer and the photothermal conversion agent, the ink receiving layer may contain a crosslinking agent, an adhesion aid, a coloring agent, an inorganic or organic agent in order to improve the film quality of the ink receiving layer and to improve the appearance. Fine particles, a coating surface condition improving agent or a plasticizer can be added. Further, a heat-coloring system or a decoloring system for forming a printout image after exposure may be added.

As a crosslinking agent for crosslinking the polymer, a diazo resin, an aromatic azide compound, an epoxy resin, an isocyanate compound, a blocked isocyanate compound, an initial hydrolysis condensate of tetraalkoxysilicon, a metal chelate compound [titanium diisopropoxide bis ( 2,4-pentadionate), aluminum tris (2,4-pentadionate), zirconium tetrakis (2,4-pentadionate), etc.], glyoxal, aldehyde compounds and methylol compounds.

As the adhesion aid, the above-mentioned diazo resin excels in adhesion to the substrate and the hydrophilic layer, but in addition to this, a silane coupling agent, an isocyanate compound and a titanium coupling agent are also useful.

As the colorant, usual dyes and pigments are used, but especially rhodamine 6G chloride, rhodamine B chloride, crystal violet, malachite green oxalate, oxazine 4 perchlorate, quinizarin,
2- (α-naphthyl) -5-phenyloxazole and coumarin-4 can be mentioned. Specifically as other dyes,
Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black B
Y, Oil Black BS, Oil Black T-505
(Above, manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI4255
5), methyl violet (CI42535), ethyl violet, methylene blue (CI52015), patent pure blue (Sumitomo Sangoku Chemical Co., Ltd.), brilliant blue, methyl green, erythricin B, basic fuchsin, m-cresol purple, auramine, 4
-P-diethylaminophenyliminaphthoquinone, cyano-p-diethylaminophenylacetanilide, and other triphenylmethane-based, diphenylmethane-based, oxazine-based, xanthene-based, iminonaphthoquinone-based, azomethine-based, or anthraquinone-based dyes or JP-A-62-62 -293247, JP-A-9-179.
The dyes described in Japanese Patent No. 290 can be mentioned. When the dye is added to the ink receiving layer, it is usually about 0.02 to 10% by mass based on the total solid content of the receiving layer,
More preferably, it is about 0.1 to 5 mass%.

Further, a fluorine-based surfactant or a silicon-based surfactant which is a well-known compound as a coating surface condition improving agent can also be used. Specifically, a surfactant having a perfluoroalkyl group or a dimethylsiloxane group is useful for adjusting the coated surface state.

As the inorganic or organic fine powder which can be used in the present invention, colloidal silica or colloidal aluminum having a particle size of 10 nm to 100 nm, and further inert particles having a particle size larger than these colloids, for example, silica particles, surface hydrophobicity. Examples thereof include converted silica particles, alumina particles, titanium dioxide particles, other heavy metal particles, clay and talc. The addition of these inorganic or organic fine powders to the ink receiving layer has the effect of improving the adhesiveness with the hydrophilic layer above and increasing the printing durability in printing. The addition ratio of these fine powders in the ink receiving layer is 80% by mass or less and preferably 40% by mass or less based on the total amount.

If necessary, a plasticizer is added to the ink receiving layer of the present invention in order to impart flexibility to the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, oligomers of acrylic acid or methacrylic acid. And polymers are used.

Further, in the ink receiving layer of the present invention, it is preferable to add a color-forming or decolorizing compound in order to make the image area and the non-image area clear when exposed. For example, leuco dyes (leucomalachite green, leuco crystal violet, lactones of crystal violet, etc.) and PH discoloring dyes (eg ethyl violet, Victoria Poor Blue BOH, etc.) along with thermal acid generators such as diazo compounds and diphenyliodonium salts. Dye) is used. In addition, a combination of an acid color dye and an acidic binder as described in EP897134 is also effective. In this case, the bond in the association state forming the dye is broken by heating, the lactone body is formed, and the color changes from colorless to colorless. The addition ratio of these color forming systems is 10% by mass or less, preferably 5% by mass or less, based on the total amount in the receiving layer.

Solvents for coating the ink receiving layer include alcohols (methanol, ethanol, propyl alcohol, ethylene glycol, diethylene glycol,
Propylene glycol, dipropylene glycol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, etc.), ethers (tetrahydrofuran, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, tetrahydropyran, etc.), ketones (acetone, methyl ethyl ketone, Acetylacetone etc.), esters (methyl acetate, ethylene glycol monomethyl monoacetate etc.), amides (formamide, N-methylformamide, pyrrolidone, N-methylpyrrolidone etc.), gamma-butyrolactone, methyl lactate, ethyl lactate etc. can be used. it can. These solvents are used alone or in a mixed state. When the coating liquid is prepared, the concentration of the ink receiving layer constituent components (total solid content including additives) in the solvent is preferably 1 to 50% by mass. In addition, the coating can be formed not only from the above organic solvent but also from an aqueous emulsion. In this case, the concentration is preferably 5% by mass to 50% by mass.

The mass of the ink receiving layer of the present invention after coating and drying is not particularly limited, but may be 0.1 g / m ² or more. When it is provided on a metal plate, it also functions as a heat insulating layer, so 0.4 g / m ² or more is desirable. If the ink receiving layer is too thin, the heat generated will be dissipated to the metal plate and the sensitivity will decrease. In addition, in the case of a hydrophilic metal plate, abrasion resistance is required for the ink receiving layer, so that printing durability cannot be ensured. When a lipophilic plastic film is used as the substrate, the ink receiving layer may serve as an adhesive layer with the upper layer, so that the coating amount may be smaller than that of the metal plate, 0.05 g / M ² or more is preferable.

The hydrophilic layer used in the present invention is an oxide of at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony and transition metals. Alternatively, it is formed by applying a solution containing a colloid of hydroxide. Among the elements constituting the colloidal oxide or hydroxide used in the present invention, aluminum, silicon, titanium and zirconium can be mentioned, and silicon is particularly preferable.

The colloidal particles used in the present invention generally have a particle size of 2 nm to 500 nm, and silica has a particle size of 5 n.
A spherical shape of m to 100 nm is preferable in the present invention. Spherical particles of 10 nm to 50 nm have particle sizes of 50 nm to 4
A pearl neck-shaped colloid having a length of 00 nm can also be used. Furthermore, feather-like particles of 100 nm × 10 nm such as aluminum colloid are also effective. These colloids can be produced by various known methods such as hydrolysis of a halide or alkoxy compound of the above element or condensation of hydroxide of the above element. These colloidal dispersions are manufactured by Nissan Chemical Industries, Ltd.
You can also purchase commercial products such as.

Further, the coating liquid for the hydrophilic layer of the present invention preferably contains a hydrophilic resin, and examples of the hydrophilic resin used in the hydrophilic layer of the present invention include hydroxy, carboxy, hydroxyethyl, hydroxypropyl and amino. ,
Those having a hydrophilic group such as aminoethyl, aminopropyl and carboxymethyl are preferable. Specific hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, carboxymethyl cellulose and sodium salts thereof, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acid. And salts thereof, polymethacrylic acid and salts thereof, homopolymers or copolymers of hydroxyethyl methacrylate, homopolymers or copolymers of hydroxyethyl acrylate, homopolymers or copolymers of hydroxypropyl methacrylate, hydroxy Propyl acrylate homopolymer or copolymer, hydroxybutyl methacrylate homopolymer or copolymer, hydroxybutyl acrylate homopolymer or copolymer, polyethylene glycol, polypropylene group Kohl, polyvinyl alcohol, hydrolyzed polyvinyl acetate having a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, homopolymers and copolymers of acrylamide, homopolymers and polymers of methacrylamide, Examples thereof include homopolymers and copolymers of N-methylolacrylamide.

A particularly preferred hydrophilic resin is a polymer containing a hydroxy group or a carboxy group, and among them, a polymer containing a hydroxy group is preferred. Specifically, a homopolymer or copolymer of hydroxyethyl acrylate or hydroxyethyl methacrylate is most suitable.

The addition ratio of these hydrophilic resins is preferably 1 to 30% by mass, and particularly preferably 5 to 20% by mass based on the total solid content of the hydrophilic layer. If it is less than this range, the printing durability is not sufficient, and if it is more than this range, printing stains tend to occur.

In addition to the above colloid and hydrophilic resin, a cross-linking agent for promoting cross-linking of the colloid and / or a cross-linking agent for the hydrophilic resin may be added to the hydrophilic layer of the present invention in order to enhance printing durability. Good.

As the cross-linking agent for the colloid, an initial hydrolysis condensate of tetraalkoxysilane, a metal chelate compound such as titanium bis (triethanolamine) diisopropoxide, trialkoxysilylpropyl-N, N, N-
Trialkylammonium halides or aminopropyltrialkoxysilanes are preferred. The addition ratio is preferably 5% by mass or less of the total solid content of the hydrophilic layer.

As the crosslinking agent for the hydrophilic resin, formaldehyde, glyoxal, polyisocyanate, an initial hydrolysis / condensation product of tetraalkoxysilane, a metal chelate compound such as titanium bis (triethanolamine) diisopropoxide, dimethylol urea and hexa are used. Mention may be made of methylolmelamine.

Further, the hydrophilic layer of the present invention contains a well-known fluorochemical surfactant in order to improve the surface condition of the coating.
Silicon type surfactants, polyoxyethylene type surfactants, etc. may be added.

The weight of the hydrophilic layer of the present invention after coating and drying is
It is preferably 0.1 g / m ² to 3 g / m ² . More preferably, it is 0.4 g / m ² to 2 g / m ² . When the thickness of the hydrophilic layer is too thin, the durability of the hydrophilic layer is poor and the printing durability during printing is poor. If it is too thick, a large amount of energy is required to ablationally separate the hydrophilic layer from the lower ink receiving layer, and a long drawing time is required when exposing with a laser. Sex decreases. When writing is performed using a general commercially available semiconductor laser, it is 300 to 400 mJ / at a thickness of about 0.5 g / m ^2.
The energy of cm ² is 400 at a thickness of about 1.5 g / m ^2.
Energy of ~ 500 mJ / cm ² is required.

As the substrate coated with the ink receiving layer used in the present invention, a dimensionally stable plate is used.
Paper, lipophilic plastic (eg, polyethylene, polypropylene, polystyrene, etc.) laminated paper, metal plate (eg, aluminum, zinc, copper, nickel, stainless steel plate, etc.), plastic film (eg, cellulose diacetate, trisodium) Cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate,
Cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper or plastic film laminated or vapor-deposited with the above metals, and the like.

Preferred substrates are polyethylene terephthalate film, polycarbonate film, aluminum or steel plate, or aluminum or steel plate laminated with a lipophilic plastic film.

As the aluminum plate used in the present invention, an aluminum plate made of a publicly known and publicly known material can be appropriately used.

It is preferable to roughen the surface of the aluminum plate before using it. When the ink receiving layer made of an organic polymer is applied by roughening, the adhesiveness with the substrate can be easily secured. For the surface roughening, a well-known and publicly available aluminum plate surface treatment technique can be used.

The heat-sensitive lithographic printing plate precursor of the present invention adsorbs lipophilic components in the air when the plate is stored for a long period of time or is stored around the printing machine before printing, or when it is handled, oil or Dirt may be generated during printing by touching it with a finger that is dirty with ink. Further, in the ablation, there is a problem that the platesetter optical system and the like are contaminated due to scattering of the decomposed and removed substances. An overcoat layer made of a water-soluble resin can be provided on the hydrophilic layer in order to prevent such a print stain problem and suppress dust scattering due to exposure ablation.

The water-soluble overcoat layer used in the present invention has a film-forming ability and is a resin selected from water-soluble polymer compounds which can be easily removed at the time of printing, such as polyvinyl acetate (however, the hydrolysis rate is 65% or more), polyacrylic acid, its alkali metal salt or amine salt, polyacrylic acid copolymer, its alkali metal salt or amine salt,
Polymethacrylic acid, its alkali metal salt or amine salt, polymethacrylic acid copolymer, its alkali metal salt or amine salt, polyacrylamide, its copolymer,
Polyhydroxyethyl acrylate, polyvinylpyrrolidone, copolymers thereof, polyvinyl methyl ether, vinyl methyl ether / maleic anhydride copolymer, poly-2
-Acrylamido-2-methyl-1-propanesulfonic acid, its alkali metal salt or amine salt, poly-2-
Acrylamide-2-methyl-1-propanesulfonic acid copolymer, its alkali metal salt or amine salt, gum arabic, fibrin derivative (for example, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, etc.), its modified product, white Examples thereof include dextrin, pullulan, enzyme-decomposed etherified dextrin and the like. In addition, two or more kinds of these resins may be mixed and used depending on the purpose.

In addition to the above, a nonionic surfactant such as polyoxyethylene nonylphenyl ether is added to the overcoat layer for the purpose of ensuring coating uniformity.

Further, a photothermal conversion agent may be added to the overcoat layer of the present invention in order to enhance heat sensitivity. The light-heat converting agent which can be added to the overcoat layer may be the above-mentioned infrared absorbing pigment or dye, but is preferably hydrophilized carbon black or a water-soluble dye.

The pigment or dye is 1 to 70% by mass, preferably 2 to 50% by mass, of the total solid content of the overcoat layer, particularly preferably 2 to 30% by mass in the case of a dye, and particularly preferably 2 to 30% by mass in the case of a pigment. It is a ratio of 20 to 50 mass%. In the present invention, since the photothermal conversion agent is added to the ink receiving layer, the amount of the photothermal conversion agent can be set small as necessary even when the photothermal conversion agent is added to the overcoat layer.

The thickness of the overcoat layer used in the present invention is preferably 0.05 μm to 4.0 μm, and more preferably 0.1 μm to 1.0 μm. Too thick,
It takes time to remove the overcoat layer during printing,
In addition, a large amount of the water-soluble resin that has melted out affects dampening water, which causes adverse effects such as the occurrence of roller strips during printing, and the fact that the ink does not adhere to the image area. If it is too thin, the film formability may be impaired.

The heat-sensitive lithographic printing plate precursor of the invention is image-formed by heat. Specifically, direct image-like recording with a thermal recording head, scanning exposure with an infrared laser, high-illuminance flash exposure with a xenon discharge lamp, infrared lamp exposure, etc. are used, but a semiconductor that emits infrared rays with a wavelength of 700 to 1200 nm. Exposure with a solid-state high-power infrared laser such as a laser or a YAG laser is preferable. The image-exposed printing original plate of the present invention can be mounted in a printing machine without further treatment. Alternatively, the printing original plate may be attached to the printing machine, laser-exposed on the printing machine, and printing may be performed as it is. When printing is started using the ink and fountain solution, the ink is inked in the ink receiving layer in the exposed area and printing is started.

[0063]

The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. Example 1 (Production of Substrate) 0.01% by mass of aluminum, 0.03% by mass of titanium, 0.3% by mass of iron and 0.3% of iron on 99.5% by mass of aluminum.
JIS A105 containing 0.1% by mass of silicon and 0.1% by mass of silicon
0 Aluminum material 0.24 mm thick rolled plate
20% by mass aqueous suspension of mesh pumicestone (manufactured by Kyoritsu Kiln) and rotating nylon brush (6,10-nylon)
The surface was grained by using and and washed well with water. This was immersed in a 15 mass% sodium hydroxide aqueous solution (containing 4.5 mass% of aluminum) to perform etching so that the amount of aluminum dissolved was 5 g / m ² , and then washed with running water. Further, it is neutralized with 1% by mass nitric acid, and then in a 0.7% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum), a rectangular wave having a voltage at the anode of 10.5 V and a voltage at the cathode of 9.3 V. An electrolytic surface roughening treatment was performed using an alternating waveform voltage (current ratio r = 0.90, current waveform described in Japanese Patent Publication No. 58-5796) in an amount of electricity of 160 clones / dm ^{2 at} the anode time. It was After washing with water, 10% by mass at 35 ° C
It was immersed in a sodium hydroxide aqueous solution, etched so that the amount of aluminum dissolved was 1 g / m ² , and then washed with water. Next, it was immersed in a 30% by mass sulfuric acid aqueous solution at 50 ° C., desmutted, and then washed with water.

Further, a porous anodic oxide film forming treatment was carried out using a direct current in a 20% by mass aqueous solution of sulfuric acid (containing 0.8% by mass of aluminum) at 35 ° C. That is, electrolysis was performed at a current density of 15 A / dm ² , and the weight of the anodized film was adjusted to 3.7 g / m ² by adjusting the electrolysis time, followed by washing with water and drying. The center line average roughness (Ra) of the aluminum substrate obtained as described above was 0.53 μm.

(Coating of ink receiving layer) On the above-mentioned substrate, a coating liquid for ink receiving layer having the following composition was applied in a dry coating weight of 0.42.
It was applied so as to be g / m ² and dried at 100 ° C. for 1 minute to form an ink receiving layer.

[0066] (Coating liquid formulation for ink receiving layer) N- (p-aminosulfonylphenyl) methacrylamide /   Methyl methacrylate / acrylonitrile /   2-hydroxyethyl methacrylate   = 40/10/30/20 mass% copolymer   (Weight average molecular weight 20,000) 3.0 g Polymethylmethacrylate (weight average molecular weight 2,500) 0.5g Infrared absorbing dye (A) 0.7g Ethylene glycol monomethyl ether 50 g Methyl ethyl ketone 47 g

[0067]

[Chemical 5]

(Preparation of heat-sensitive lithographic printing plate precursor) 0.1 g of polyacrylic acid (weight average molecular weight 250,000), methanol silica (manufactured by Nissan Chemical Co., Ltd .: from a methanol solution containing 30% by mass of silica particles of 10 nm to 20 nm) 3 g of colloid), 16 g of methanol, 1 g of methyl lactate
Is applied onto the above-mentioned ink receiving layer so as to have a dry coating weight of 0.4 g / m ² and dried at 100 ° C. for 1 minute to form a hydrophilic layer to obtain a heat-sensitive lithographic printing plate precursor. It was

(Preparation of lithographic printing plate) The above-mentioned heat-sensitive lithographic printing plate precursor was mounted on a 40 W trend setter (plate setter equipped with 40 W 830 nm semiconductor laser) of CREO of Canada and exposed at an energy of 200 mJ / cm ² . The exposed original plate was directly attached to a Komori Sprint printing machine without any treatment, and a dampening water and ink (Dainippon Ink and Co., Ltd.) consisting of a 4% by volume aqueous solution of PS dampening water IF102 manufactured by Fuji Photo Film Co., Ltd. When printing was performed using GEOS-G black M) manufactured by GEOS-G, from the initial stage of printing, ink was inked in the image area and 10,000 good printed areas were obtained without stains on the non-image areas. Then, after printing the plate surface using PS Multi Cleaner manufactured by Fuji Photo Film Co., Ltd., the printing was continued. As a result, a good printed matter with good ink buildup and no stain on the non-image area was obtained. , 00
0 copies were obtained.

Example 2 Epicoat 1009 was coated with the aminosulfonylphenyl methacrylamide copolymer of the coating liquid for the ink receiving layer of Example 1.
(Japan Epoxy Resin Co., Ltd. bisphenol A-
Epichlorohydrin type epoxy resin, weight average molecular weight 3,750), and polyacrylic acid were used in Epicoat 1001.
(Japan Epoxy Resin Co., Ltd. bisphenol A-
Epichlorohydrin type epoxy resin, weight average molecular weight 9
A heat-sensitive lithographic printing plate precursor was obtained in the same manner as in the example except that it was replaced with (00). This original plate was exposed and printed in the same manner as in Example 1. As a result, from the initial stage of printing, ink was inked in the image area and 10,000 good prints were obtained without stains on the non-image area. Then, after printing the plate surface using PS Multi Cleaner manufactured by Fuji Photo Film Co., Ltd., the printing was continued. As a result, a good printed matter with good ink buildup and no stain on the non-image area was obtained. 1,000 copies were obtained.

Example 3 Epicoat 1009 of the ink-receptive layer coating liquid of Example 2
Was added in the same manner as in Example 2 except that the amount added was 2.45 g and the amount added Epicoat 1001 was 1.05 g.
A heat-sensitive lithographic printing plate precursor was obtained. This original plate was exposed and printed in the same manner as in Example 1. As a result, from the initial stage of printing, ink was inked in the image area and 10,000 good prints were obtained without stains on the non-image area. Then, after printing the plate surface using PS Multi Cleaner manufactured by Fuji Photo Film Co., Ltd., the printing was continued. As a result, a good printed matter with good ink buildup and no stain on the non-image area was further obtained. , 00
0 copies were obtained.

Example 4 Epicoat 1009 of the ink-receptive layer coating liquid of Example 2
In the same manner as in Example 2 except that the amount added of 1.75 g and the amount added of Epicoat 1001 were changed to 1.75 g.
A heat-sensitive lithographic printing plate precursor was obtained. This original plate was exposed and printed in the same manner as in Example 1. As a result, from the initial stage of printing, ink was inked in the image area and 10,000 good prints were obtained without stains on the non-image area. Next, when the printing was continued after printing the plate surface using PS Multi Cleaner manufactured by Fuji Photo Film Co., Ltd., the inking property of the ink in the image area was deteriorated. For this reason, it was necessary to increase the amount of ink supplied, but 5,000 copies of good printed matter with good ink buildup and no stain on the non-image area were obtained.

Comparative Example 1 Epicoat 1009 of the ink-receptive layer coating liquid of Example 2
A heat-sensitive lithographic printing plate precursor was obtained in the same manner as in Example 2 except that the amount of was added to 3.5 g and Epicoat 1001 was not added. When this original plate was exposed and printed in the same manner as in Example 1, since the adhesion of the hydrophilic layer in the image area was insufficiently reduced, ink could not be inked in the image area at the beginning of printing, and a good printed matter could be obtained. could not.

Examples 5 to 10 Polymer A shown in Table 1 is an aminosulfonylphenyl methacrylamide copolymer of the ink receiving layer coating solution of Example 1.
A heat-sensitive lithographic printing plate precursor was obtained in the same manner as in Example 1 except that the polyacrylic acid was changed to the polymer B (addition amount 0.7 g) shown in Table 1 (addition amount 2.8 g). When these original plates were exposed and printed in the same manner as in Example 1,
From the initial stage of printing, ink was deposited on the image area, and 10,000 good prints were obtained without stains on the non-image area. Then, after printing the plate surface using PS Multi Cleaner manufactured by Fuji Photo Film Co., Ltd., the printing was continued. As a result, a good printed matter with good ink buildup and no stain on the non-image area was further obtained. 1,000 copies were obtained.

[0075]

[Table 1]

[0076]

INDUSTRIAL APPLICABILITY The heat-sensitive lithographic printing plate precursor according to the present invention can be mounted on a printing machine as it is without performing a development process for printing, and has excellent printing durability and stain resistance during printing. By containing two or more kinds of polymers having different molecular weights in the ink receiving layer, both sensitivity and plate cleaner resistance can be achieved.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H025 AA01 AA12 AB03 AC08 AD01                       CB55 CC11 DA36 DA37 FA21                 2H096 AA06 BA20 CA05 EA04 EA23                       GA43 GA45                 2H114 AA04 AA22 AA23 AA24 AA27                       AA30 BA02 BA10 DA08 DA41                       DA75 EA01 EA03 EA04 EA08                       FA06 GA01 GA34

Claims (2)

[Claims] 1. An ink receiving layer containing a) two or more polymers having different weight average molecular weights and a photothermal conversion agent on a support, and b) beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin. , A zirconium, iron, vanadium, antimony and transition metal, a heat-sensitive lithographic printing plate provided with a hydrophilic layer coated with a solution containing a colloid of an oxide or hydroxide of at least one element selected in this order. Original plate. 2. The two or more polymers having different weight average molecular weights are at least 500 to 30 in weight average molecular weight.
Low molecular weight polymer of 00 and weight average molecular weight of 3000 to 1
2. The heat-sensitive lithographic printing plate precursor according to claim 1, which is composed of a high molecular weight polymer of 00000.