JP2001315450A - Heat sensitive lithographic printing original film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sensitive lithographic printing original film with a plastic support, which can be directly installed to a printing machine and printed without treatment after exposure and the plate wear of which is im proved. SOLUTION: This heat sensitive lithographic printing original film has a lipophilic adhesive bond layer and a hydrophilic layer including microcapsules, each involves a lipophilic component, which converts to an image part under heat, and a hydrophilic binder polymer, on a plastic board under the condition that at least either one layer between the lipophilic adhesive bond layer and the hydrophilic layer includes a photothermal converting agent. In addition, the center-line mean roughness Ra of the surface of the plastic board is set to be 0.15 to 1.0 μm.

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 for a computer-to-plate system which does not require development. More specifically, it is possible to record an image by infrared scanning exposure based on a digital signal, and the recorded image can be directly attached to a printing machine and printed without going through a conventional developing process using a liquid. It relates to a possible heat-sensitive lithographic printing plate.

[0002]

2. Description of the Related Art Numerous studies have been made on lithographic printing original plates for computer-to-plate systems, which have made remarkable progress in recent years. Among them, after exposure, we aim to further streamline the process and solve the waste liquid treatment problem.
Development-free lithographic printing original plates that can be mounted on a printing press and printed without performing development processing have been studied, and various methods have been proposed. One promising method is a heat-sensitive lithographic printing plate having a hydrophilic layer in which microcapsules in which a lipophilic component is encapsulated in a hydrophilic binder polymer are dispersed. That is, by applying heat to the hydrophilic layer, the microcapsules are broken, the lipophilic component is leached and fused, and the surface of the hydrophilic layer is converted into a lipophilic image area. A printable image composed of a hydrophilic portion and a lipophilic portion can be formed at a stroke only by exposure, so that printing can be performed without development.

A heat-sensitive lithographic printing plate having a hydrophilic layer in which microcapsules containing a lipophilic component which is converted into an image area by heat in a hydrophilic binder polymer is dispersed is disclosed, for example, in JP-A-7-1849 and JP-A-7-1849. These are known from JP-A-1850, JP-A-10-6468 and JP-A-11-70756. These publications also describe that in the case of laser printing, a photothermal conversion agent having an absorption band at a laser emission wavelength is added to a lipophilic component.

[0004]

However, the above technique has a problem that the printing durability is insufficient. Therefore,
It is an object of the present invention to solve this problem. That is, an object of the present invention is to provide a heat-sensitive lithographic printing plate precursor that can be directly mounted on a printing press and printed without any processing after exposure and has improved printing durability. .

[0005]

As a result of intensive studies, the present inventor has found that when a plastic substrate is used as a support, the surface thereof is roughened by graining or mat coating to improve printing durability. This led to the present invention. That is, the present invention is as follows.

[0006] 1. On a plastic substrate, a lipophilic adhesive layer, and a hydrophilic layer containing a hydrophilic binder polymer containing microcapsules containing a lipophilic component that is converted into an image area by heat, and a lipophilic adhesive layer and a hydrophilic layer A heat-sensitive lithographic printing plate in which at least one layer contains a light-to-heat conversion agent, wherein the center line average roughness Ra of the surface of the plastic substrate is 0.15 to 1.0 μm. Original plate.

[0007] 2. A lipophilic adhesive layer, a hydrophilic layer and a water-soluble overcoat layer as described in 1 above are provided on a plastic substrate, and at least one of the lipophilic adhesive layer, the hydrophilic layer and the water-soluble overcoat layer contains a photothermal conversion agent. A heat-sensitive lithographic printing plate precursor comprising: a heat-sensitive lithographic printing plate precursor having a center line average roughness Ra of 0.15 to 1.0 μm on the surface of a plastic substrate.

[0008] JP-A-7-1849, 7-185
Nos. 0, 10-6468, and 11-7075.
In Japanese Patent Application Laid-Open No. 6-204, etc., it is possible to use a substrate which has been subjected to a surface treatment to improve the adhesion to a material which comes into contact with the substrate. Describes that there are corona discharge treatment, blast treatment and the like. However, these publications do not disclose or suggest that high printing durability can be achieved by using a constant surface roughness as in the present invention.

[0009]

Embodiments of the present invention will be described below in detail. The plastic substrate used in the present invention is a plastic sheet whose surface is roughened. Examples of the material of the plastic sheet include polyethylene terephthalate (hereinafter referred to as PET), polycarbonate, cellulose triacetate, and a composite material such as paper or aluminum laminated with PET. Particularly preferred is PET.

The thickness of the plastic sheet used in the present invention is preferably 50 to 400 μm, more preferably 100 to 300 μm. If it is 50 μm or less, dimensional stability is lacking, and if it is 400 μm or more, it is disadvantageous in terms of cost.

The plastic substrate of the present invention can be obtained by roughening the surface of a raw plastic sheet. The center line average roughness Ra of the roughened plastic substrate surface of the present invention is preferably 0.15 to 1.0 μm. More preferably, it is 0.35 to 0.6 μm. Below this range, the effect of improving printing durability is small, and above this range, printing stains are likely to occur.

The roughening of the raw plastic sheet can be carried out by mechanical graining or application of a matting agent-containing resin (hereinafter referred to as mat coating).
The mechanical graining can be performed, for example, by spraying silica sand onto the surface of the plastic plate at high pressure. By such a mechanical graining method, a rough surface of Ra 0.2 to 1.0 μm can be obtained. The mat coating can be performed, for example, by applying a dispersion in which silica powder or the like is dispersed in a polymer onto a plastic substrate. The matte coating provides a rough surface of Ra 0.1 to 0.5 μm. A desired surface roughness can be obtained by appropriately selecting such a roughening method and conditions.

[0013] Such a roughened plastic sheet used in the present invention can be purchased from a commercial product such as Panac Co., Ltd. For example, the company's thickness 180
μm PET sheet.
a0.40 μm, Ra0.48 μm, Ra0.67 μm
Are preferred, and as a mat-coated product, K
B-mat 188N-30 (Ra 0.28 μm), KB
-Matt 188N-100 (Ra 0.24 µm) or the like is preferable.

Suitable organic polymers for use in the lipophilic adhesive layer of the present invention include polyurethane resins, for example, epoxy resins such as Estan # 5715 manufactured by BF Goodrich.
For example, Epicoat 100 manufactured by Yuka Shell Epoxy Co., Ltd.
7, epicoat 1009, etc., polyvinyl acetal resins such as polyvinyl formal and polyvinyl butyral, polyester resins, acrylic resins, novolak resins, resole resins, vinyl resins, Saran resins, and the like.

[0015] A nonionic surfactant or a fluorine-based surfactant can be added to the lipophilic adhesive layer for the purpose of ensuring uniformity of coating. Dry coating amount of the lipophilic adhesive layer is preferably 0.1 to 5.0 g / m ^2. More preferably, it is 0.2 to 1.0 g / m ² .
Within this range, a good adhesive effect can be obtained.

The hydrophilic layer used in the present invention is a layer containing microcapsules containing a lipophilic component and a hydrophilic binder polymer, and is converted into an image area by heat.

The hydrophilic binder polymer used in the present invention includes poly (meth) acrylate, poly (meth) acrylic acid, poly (meth) acrylamide, polyoxyalkylene, polyurethane, polyester and polyamide. , Polyamine-based, polyvinyl-based, epoxy ring-opening addition-polymerization-based, polysaccharide-based or composites thereof, such as carboxyl group, phosphate group, sulfonic group, amino group or their salts, hydroxyl group, amide group ,
It is a polymer containing one or more kinds of hydrophilic functional groups such as polyoxyethylene groups and a plurality thereof, and is preferably three-dimensionally crosslinked.

Among them, any one of a hydroxyl group, a carboxyl group or an alkali metal salt thereof, a sulfone group or an amine salt thereof, an alkali metal salt and an alkaline earth metal salt, an amino group or a hydrohalide salt thereof, or an amide group on the side chain. Alternatively, a hydrophilic binder polymer having a segment in which these are combined repeatedly, and a hydrophilic binder polymer having a polyoxyethylene group in a part of the hydrophilic functional group and the main chain segment are preferable because of high hydrophilicity. In addition to these, those having a urethane bond or a urea bond in the main chain or side chain of the hydrophilic binder polymer are more preferable because not only the hydrophilicity but also the printing durability of the non-image area are improved.

The hydrophilic polymer used in the present invention can be used together with the hydrophilic polymer crosslinking means described in JP-A-7-1849 and JP-A-11-70756. For example, it can be used together with a crosslinking means such as an isocyanate compound, an epoxy compound, a photopolymerization initiator, a thermal polymerization initiator or a polyvalent metal ion.

Examples of the lipophilic component used in the present invention include phenyl isocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate,
4'-diphenylmethane diisocyanate, 3,3'-
Dimethylbiphenyl-4,4′-diisocyanate,
Isocyanate compounds such as oligomers or polymers of 1,5-naphthalenediisocyanate, tolidine diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, 2-isocyanatoethyl (meth) acrylate;

N, N'-methylenebisacrylamide,
(Meth) acryloylmorpholine, N-methyl (meth)
Acrylamide, N, N′-dimethyl (meth) acrylamide, N, N′-dimethylaminopropyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, diethylene glycol di (meth) acrylate,
Tetraethylene glycol di (meth) acrylate,
Trimethylolpropane tri (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, polyethylene glycol di (meth) acrylate (PEG number average molecular weight 400), polyethylene glycol di (meth)
Polymerizable compounds such as acrylates (PEG number average molecular weight 600);

Propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether,
Polyfunctional epoxy compounds such as polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl ether of bisphenol A, and hydrogenated bisphenol A diglycidyl ether can be used.

Further, known (meth) acrylic copolymers, urethane acrylates, and diazo resins before crosslinking, which are used as image components of existing PS plates, can also be used.

The encapsulation of the lipophilic component can be performed by a known encapsulation method, for example, an interfacial polymerization method for forming a capsule membrane, in-s
It can be performed by an itu method, a complex coacervate method, a phase separation method from an organic solution system, or the like.

The surface of the capsule outer shell is not particularly limited as long as the non-image portion does not stain when printed in a state where the microcapsules are contained in the hydrophilic layer.
It is preferably hydrophilic. The microcapsule size is 10 μm or less on average, and 5 μm on average for high resolution applications.
m or less is preferable. If the ratio of the lipophilic component to the entire capsule is too low, the efficiency of image formation decreases, so that the average of the lipophilic component is 0.
It is preferably at least 01 μm.

The amount of the microencapsulated lipophilic component to be used may be determined from the viewpoints of sensitivity and printing durability required for each printing application. Usually, the microcapsule / hydrophilic binder polymer weight ratio is used in the range of 1/20 to 10/1. Preferably, it is used in the range of 1/15 to 5/1. When the proportion of the lipophilic component is too small, the sensitivity is remarkably reduced. When the proportion of the lipophilic component is too large, the printing durability is remarkably reduced.

In order to visualize the exposed portion and facilitate plate inspection, a known thermosensitive dye which develops color only in the exposed portion can be used in combination with the lipophilic component of the present invention. For example, there is a combination of 3-diethylamino-6-methyl-7-anilinofluoran with a leuco dye such as bisphenol A and a ground developer.

The solvent for coating the hydrophilic layer of the present invention includes water,
Ethanol, isopropanol, alcohols such as n-butanol, acetone, ketones such as methyl ethyl ketone, diethylene glycol diethyl ether,
Diisopropyl ether, dioxane, tetrahydrofuran, ethers such as diethylene glycol, ethyl acetate, butyl acetate, methyl lactate, esters such as ethyl lactate, toluene, aromatic hydrocarbons such as xylene, n-hexane, aliphatic hydrocarbons such as decalin,
Dimethylformamide, dimethylsulfoxide, acetonitrile, γ-butyrolactone, or a mixed solvent thereof can be used.

The amount of the solid content on the support obtained after coating and drying of the hydrophilic layer of the present invention is generally 0.5 to 5.0 g.
/ M ² is preferred. As the coating method, various methods can be used, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

The heat-sensitive lithographic printing plate of the present invention can have a water-soluble overcoat layer on the hydrophilic layer. The overcoat layer can prevent the hydrophilic layer from being contaminated with a lipophilic substance during storage and handling of the printing plate.
Furthermore, by including the photothermal conversion agent in the overcoat layer, it is possible to avoid the deterioration of the hydrophilicity and film quality of the hydrophilic layer due to the addition of a large amount of the photothermal conversion agent to the hydrophilic layer, thereby increasing the sensitivity. .

The water-soluble overcoat layer that can be used in the present invention can be easily removed at the time of printing and contains a resin selected from water-soluble polymer compounds. As the water-soluble polymer compound used herein, a film formed by coating and drying has a film-forming ability, specifically, polyvinyl acetate (provided that the hydrolysis rate is 65% or more), polyacrylic Acid and its alkali metal salt or amine salt, acrylic acid copolymer and its alkali metal salt or amine salt, polymethacrylic acid and its alkali metal salt or amine salt, methacrylic acid copolymer and its alkali metal salt or amine salt, Acrylamide homopolymer and copolymer, polyhydroxyethyl acrylate, vinylpyrrolidone homopolymer and copolymer,
Polyvinyl methyl ether, vinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamide-2
-Methyl-1-propanesulfonic acid and its alkali metal salt or amine salt, 2-acrylamido-2-methyl-1-propanesulfonic acid copolymer and its alkali metal salt or amine salt, gum arabic, cellulose derivatives (for example, , Carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, white dextrin, pullulan, enzymatically decomposed etherified dextrin and the like. Further, according to the purpose, two or more of these resins can be used in combination.

In addition, a nonionic surfactant can be mainly added to the overcoat layer in the case of aqueous solution application for the purpose of ensuring uniformity of application. Specific examples of such a nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan triolate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecyl ether, and the like. . The proportion of the nonionic surfactant in the total solid content of the overcoat layer is preferably 0.05 to 5% by weight, and more preferably 1 to 3% by weight.

The thickness of the overcoat layer according to the present invention is 0.1.
It is preferably from 0.5 to 4.0 μm, more preferably from 0.1 to 4.0 μm.
１．０1.0 μm. Within this range, good lipophilic substance contamination can be prevented without impairing the film properties. If it is too thick, it will take time to remove the overcoat layer during printing, or a large amount of the water-soluble resin will affect the fountain solution, causing roller strips during printing, or causing ink to deposit on the image area. Adverse effects, such as not doing, are likely to occur.

At least one of the lipophilic adhesive layer, hydrophilic layer, and water-soluble overcoat layer of the present invention contains a photothermal conversion agent that absorbs infrared rays and generates heat. Such a photothermal conversion agent may be any light-absorbing substance having an absorption band in at least a part of 700 to 1200 nm, and various pigments or dyes can be used.

Examples of pigments include commercially available pigment and color index (CI) handbook, "Latest Pigment Handbook" (edited by Japan Pigment Technical Association, 1977), and "Latest Pigment Application Technology" (CMC Publishing, 1986). And "printing ink technology" (CMC Publishing, 1984) can be used.

These pigments can be used after being subjected to a known surface treatment, if necessary, in order to improve the dispersibility in the layer to which the pigment is added. Surface treatment methods include a method of surface-coating a hydrophilic resin or a lipophilic resin, a method of attaching a surfactant, and a reactive substance (for example, silica sol, alumina sol, a silane coupling agent or an epoxy compound,
A method of bonding an isocyanate compound) to the surface of the pigment. The pigment to be added to the hydrophilic layer is preferably a pigment whose surface is coated with a hydrophilic resin or silica sol so as to be easily dispersed in a water-soluble resin and not to impair the hydrophilicity. The particle size of the pigment is preferably in the range of 0.01 μm to 1 μm, and more preferably in the range of 0.01 μm to 0.5 μm. As a method for dispersing the pigment, a known dispersion technique used in the production of ink or toner can be used. Among the pigments, a particularly preferred pigment is carbon black.

Examples of the dye include commercially available dyes and literatures (eg, “Dye Handbook” edited by The Society of Synthetic Organic Chemistry, 1975, “Chemical Industry”, May 1986, May 45, 1986, “Near-infrared absorbing dyes”). Known dyes described in "Development and Market Trend of Functional Dyes in the 90's", Chapter 2, Section 2.3 (1990), or patents can be used.
Specifically, azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes,
Infrared absorbing dyes such as carbonium dyes, quinone imine dyes, polymethine dyes and cyanine dyes are preferred.

Further, for example, see JP-A-58-12524.
No. 6, JP-A-59-84356, JP-A-60-787
No. 87, etc .;
173696, JP-A-58-181690, methine dyes described in JP-A-58-194595, and the like;
JP-A-58-112793, JP-A-58-22479
No. 3, JP-A-59-48187, JP-A-59-739
No. 96, JP-A-60-52940, JP-A-60-63
744, etc .; squarylium dyes described in JP-A-58-112792; cyanine dyes described in British Patent 434,875; and dyes described in U.S. Pat. No. 4,756,993. And cyanine dyes described in U.S. Pat. No. 4,973,572, and dyes described in JP-A-10-268512.

As a dye, US Pat. No. 5,156,
No. 938 is also preferably used, and substituted arylbenzo (thio) pyrylium salts described in U.S. Pat. No. 3,881,924;
No. 42645 (U.S. Pat. No. 4,327,169), a trimethinethiapyrylium salt described in JP-A-58-1810.
No. 51, No. 58-220143, No. 59-41363
Nos. 59-84248, 59-84249, 59-146063, and 59-146061 and pyrylium compounds described in JP-A-59-2161.
No. 46, a cyanine dye disclosed in U.S. Pat. No. 4,283,4.
No. 75, pentamethine thiopyrylium salt and the like, and pyrilium compounds disclosed in JP-B-5-13514 and JP-A-5-19702;
I-178, Epolite III-130, Epolite III-
125 and the like are also preferably used. Among them, particularly preferred dyes to be contained in the overcoat layer or the hydrophilic layer binder polymer are water-soluble dyes, and specific examples thereof are listed below by structural formulas.

[0040]

Embedded image

[0041]

Embedded image

The photothermal conversion agent used together with the lipophilic component in the microcapsules of the hydrophilic layer of the present invention or the photothermal conversion agent for the lipophilic adhesive layer may be the above-mentioned infrared absorbing dye or pigment. Lipophilic dyes are more preferred. Specific examples include, for example, the following cyanine dyes.

[0043]

Embedded image

When the photothermal conversion agent is added to the hydrophilic layer binder polymer, it is preferably 1 to 70% by weight, more preferably 2 to 50% by weight based on the solid content of the hydrophilic layer. Within this range, good sensitivity can be obtained without impairing the hydrophilicity of the hydrophilic layer.

When the lipophilic component is contained in the lipophilic component of the microcapsule of the hydrophilic layer, it is preferably 0.5
-20% by weight, more preferably 1-10% by weight.
Good sensitivity is obtained within this range.

When the light-to-heat converting agent is added to the lipophilic adhesive layer, the addition ratio is 1 to 40% by weight, preferably 2 to 20% by weight of the solid content of the adhesive layer. Within this range, good sensitivity can be obtained without impairing the film quality.

When the light-to-heat converting agent is added to the overcoat layer, the ratio of addition is from 1 to 70% of the solid content of the overcoat layer.
%, Preferably 2 to 50% by weight, more preferably 2 to 30% by weight when the light-to-heat conversion agent is a dye, and particularly preferably 20 to 50% by weight when the light-to-heat conversion agent is a pigment. Within this range, good sensitivity can be obtained without impairing the uniformity and film strength of the overcoat layer. When a light-to-heat conversion agent is added to the overcoat layer, the amount of the light-to-heat conversion agent in the hydrophilic layer and the adhesive layer may be reduced or may not be added depending on the addition amount.

The heat-sensitive lithographic printing plate of the present invention forms an image by heat. Specifically, direct image-like recording using a thermal recording head or the like, scanning exposure using an infrared laser, high-intensity flash exposure such as a xenon discharge lamp, or infrared lamp exposure is applied, and infrared rays having a wavelength of 700 to 1200 nm are applied. Exposure with a solid-state high-output infrared laser such as a semiconductor laser or a YAG laser that emits light is preferable.

The image-exposed printing plate can be mounted on a printing press without further processing. When printing is started using the ink and the fountain solution, the ink is deposited on the lipophilic image area formed in the hydrophilic layer, and printing proceeds. The overcoat layer is quickly dissolved and removed by contact with the fountain solution and does not affect printing. Further, as described in Japanese Patent No. 2938398, the lithographic printing original plate of the present invention is mounted on a cylinder of a printing press, and then exposed by a laser mounted on the printing press. It is also possible to start printing by ejecting ink.

[0050]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.

[Microcapsules containing lipophilic components]
Production Example of M1] Coronate L (manufactured by Nippon Polyurethane Co., Ltd.
Limethylolpropane and 2,4-tolylene diisocyanate
1 to 3 mole adduct with ethyl acetate, containing 25% by weight of ethyl acetate
Product) 1.26 g in 7.2 g of glycidyl methacrylate
To obtain an oily component. Then purification
To 120 g of water, add propylene glycol alginate
Le (Duck Lloyd LF, manufactured by Kibun Food Chemifa Corporation)
Number average molecular weight: 2 × 10 ^Five2) polyethylene glycol
0.86 g of PEG 400 (manufactured by Sanyo Chemical Industries, Ltd.)
Was mixed to prepare an aqueous phase. Then, the oil component and water
The phases are mixed at room temperature at 6000 rpm using a homogenizer.
After the emulsification, the mixture was reacted at 60 ° C. for 3 hours to obtain an average particle size of 1.
8 μm microcapsules were obtained.

[Production Example of Microcapsules M2 Encapsulating a Lipophilic Component] Solidate Coronate L10
g, 8 g of ethyl alcohol, 2 g of purified water, and 30 g of a 5% aqueous solution of polyacrylamide were placed in a container and shaken with a paint shaker at room temperature for 1 hour to prepare microcapsules of isocyanate whose fine particle surfaces were blocked. The average size of the primary dispersed particles was 1.0 μm.

[Production Example of Microcapsule M3 Encapsulating Lipophilic Component] 0.3 g of a photothermal conversion agent (dye IR-24 described in the present specification) was contained in the lipophilic component of microcapsule M1.
A microcapsule was produced in the same manner as in the production example of the microcapsule M1 except that was added.

Examples 1 to 3 and Comparative Example 1 A urethane-based adhesive (Estan # 5715 (BF) was coated on a grained PET sheet (manufactured by Panac Co., Ltd.) having a surface roughness shown in Table 1 and having a thickness of 180 μm. Goodrich Co.) was applied to a dry coating weight of 0.5 g / m ² . A hydrophilic layer coating solution A1 having the following composition, which was well stirred in advance with a paint shaker at room temperature for 30 minutes, was applied thereon with a blade coater, and then dried to form a hydrophilic layer having a thickness of 3.5 μm.

(Hydrophilic Layer Coating Solution A1) 10% by weight aqueous solution of hydrophilic resin (1) 20.0 g Microcapsules M1 80.0 g 3% by weight aqueous solution of alginic acid ester 300 g Methyl lactate 20 g

Here, the hydrophilic resin (1) has a polyacrylic acid (julymer AC10MP, manufactured by Nippon Pure Chemical Co., Ltd.) number average molecular weight of 80,000, and the alginate ester is propylene glycol alginate (Kibun Food Chemifa Co., Ltd.) Dacroid LF).

Next, the substrate having the hydrophilic layer was immersed in 1.5 liter of a 5% aqueous solution of stannic chloride pentahydrate (manufactured by Tokyo Chemical Industry Co., Ltd.) for 3 minutes, and 1 liter of purified water was used. 1
After washing with water for minutes, the hydrophilic layer was crosslinked.

An overcoat layer coating solution OC-1 having the following composition was applied on the hydrophilic layer subjected to the above treatment to prepare a heat-sensitive lithographic printing original plate. The dry coating weight of the overcoat layer was about 0.3 g / m ² .

(Overcoat Layer Coating Solution OC-1) Polyacrylic acid (weight average molecular weight 25,000) 1 g Light-to-heat converting agent (dye IR-11 described in this specification) 0.4 g Polyoxyethylene nonylphenyl ether 0 0.05g Water 39g

The original plate for printing prepared in this manner was mounted on a trend setter manufactured by Creo (a plate setter equipped with a 830 nm semiconductor laser of 40 W) and exposed at an exposure energy of 200 mJ / m ² . Next, the entire surface of the plate was irradiated with a chemical lamp at 6 J / cm ² . The original printing plate was attached to Komori Corporation printing machine Lithrone without further processing, and consisted of plate etchant EU-3 (Fuji Photo Film Co., Ltd.) / Water / isopropyl alcohol (volume ratio 1/99/10). Printing was performed using a dampening solution and Geos G black ink manufactured by Dainippon Ink and Chemicals, Inc. The results are shown in Table 1.

[0061]

[Table 1]

Example 4 Instead of the grained PET sheet used in Example 1, a mat-coated PET sheet (KB mat 188) was used.
An original plate for heat-sensitive lithographic printing was produced in the same manner as in Example except that N-30 (manufactured by Panac Co., Ltd.) was used as a support. Next, as a result of exposure and printing as in Example 1,
20,000 good prints without stains were obtained.

Example 5 On the PET sheet having a polyurethane adhesive layer used in Example 1, a hydrophilic layer coating solution A2 having the following composition, which was well stirred in advance at room temperature for 30 minutes with a paint shaker, was applied. A substrate having a hydrophilic layer was obtained.

(Hydrophilic layer coating liquid A2) 15% aqueous solution of hydrophilic resin (2) 12 g Microcapsules M2 (20% solid content) 6 g Calcium carbonate 1 g Water 19 g Methyl lactate 2 g

Here, the hydrophilic resin (2) is a copolymer of 2-hydroxyethyl methacrylate / acrylamide / acrylic acid (weight ratio 1/4/4) and has a number average molecular weight of 1
100,000. On the hydrophilic layer, the following overcoat layer coating solution OC-2 was applied, and the dry coating weight was 0.5 g / m2.
The heat-sensitive lithographic printing plate precursor having a ^second overcoat layer was produced.

(Overcoat Layer Coating Solution OC-2) Polyacrylic acid (weight average molecular weight: 25,000) 1 g Carbon black stabilized by a nonionic surfactant 20% by weight ethanol dispersion 2.5 g Methanol 26.5 g

The heat-sensitive lithographic printing plate thus prepared was exposed and printed in the same manner as in Example 1. As a result, 20,000 good printed matters free of stains were obtained.

Example 6 The following coating solution was applied to the grained PET sheet used in Example 1 with a bar at a coating solution amount of 12 ml / m ² . Then, it is dried by heating at 100 ° C. for 1 minute.
A lipophilic adhesive layer of 5 g / m ² was provided.

(Coating solution for adhesive layer) Epoxy resin (Epicoat 1009) 3 g Light-to-heat converting agent (Dye IR-24 described in this specification) 0.3 g Megafac F-177 0.04 g Methyl ethyl ketone 37 g Propylene glycol monomethyl ether 20 g

On this adhesive layer, a hydrophilic layer coating solution A3 having the following composition, which was well stirred in advance at room temperature for 30 minutes using a paint shaker, was applied to form a hydrophilic layer having a dry coating thickness of 3 μm.

(Hydrophilic Layer Coating Solution A3) 10% aqueous solution of hydrophilic resin (1) 20.0 g Microcapsules M3 80.0 g 3% aqueous solution of alginic acid ester 300 g γ-butyrolactone 3 g

Next, the substrate having the hydrophilic layer was treated with an aqueous solution of stannic chloride in the same manner as in Example 1, washed with water and dried to prepare a heat-sensitive lithographic printing plate. When this printing original plate was exposed and printed in the same manner as in Example 1, 20,000 good printed matters were obtained.

[0073]

According to the present invention, after exposure, it is possible to print directly by mounting on a printing press without performing any processing, and to perform heat-sensitive lithographic printing on a plastic support having improved printing durability. We can provide original plate.

Continued on front page F-term (reference) 2H025 AA12 AB03 AC08 AD01 BH03 BJ03 CB51 CB54 CC11 CC20 DA02 DA10 DA19 DA20 DA35 FA10 2H096 AA06 BA01 CA05 CA20 EA04 EA23 2H114 AA14 AA24 AA27 AA30 BA01 BA10 DA50 DA50 DA50 DA50 DA50 DA50 DA74 EA01 EA03 EA08 FA01 GA03

Claims (2)

[Claims] 1. A lipophilic adhesive layer on a plastic substrate.
And a microcapsule containing a lipophilic component that is converted into an image area by heat and a hydrophilic layer containing a hydrophilic binder polymer, and at least one of the lipophilic adhesive layer and the hydrophilic layer contains a photothermal conversion agent. A heat-sensitive lithographic printing original plate, wherein the plastic substrate surface has a center line average roughness Ra of 0.15 to 1.0 μm. 2. A lipophilic adhesive layer, a hydrophilic layer according to claim 1, and a water-soluble overcoat layer on a plastic substrate, wherein at least one of the lipophilic adhesive layer, the hydrophilic layer and the water-soluble overcoat layer is provided. A heat-sensitive lithographic printing original plate in which two layers contain a photothermal conversion agent, wherein the plastic substrate surface has a center line average roughness Ra of 0.15 to 1.0 μm. .