JPH09131981A - Direct drawing type waterless lithographic printing original plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the absorptivity and sensitivity of laser beams by specifying the weight ratio of carbon black and nitrocellulose when a direct drawing type waterless lithographic printing original plate is constituted by laminating successively a heat-sensitive layer containing carbon black and nitrocellulose and a silicone rubber layer on a base. SOLUTION: When a direct drawing type waterless lithographic printing original plate is constituted on a base by laminating successively a heat-sensitive layer containing carbon black and nitrocellulose and a silicone rubber layer, the weight ratio between carbon black and nitrocellulose is set as carbon black of 1.1 or more to nitrocellulose of 1, preferably 1.1-3. When the weight ratio of carbon black is smaller than 1.1, laser beams are not absorbed efficiently, and the sensitivity of a printing block is easily lowered, while when the weight ratio of carbon black is too large, the resistance to printing of the printing block is easily lowered. The absorptivity of laser beams and sensitivity thereof can be improved by the arrangement referred above first.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterless planographic printing plate precursor which can be printed without using dampening water, and more particularly to a direct drawing type waterless planographic printing plate precursor which can be directly made by laser light. Things.

[0002]

2. Description of the Related Art Direct plate making, in which an offset printing plate is produced directly from an original without using a plate making film, is simple, does not require skill, is quick in obtaining a printing plate in a short time, Utilizing features such as rationality that can be selected according to quality and cost from the system,
In addition to the light printing industry, it has begun to enter the general offset printing and gravure printing fields.

In recent years, new types of various lithographic printing materials have been developed in recent years due to rapid advances in output systems such as prepress systems, imagesetters, and laser printers.

[0004] These lithographic printing plates can be classified according to plate making methods: a method of irradiating a laser beam, a method of writing with a thermal head, a method of partially applying a voltage with a pin electrode,
A method of forming an ink repellent layer or an ink deposited layer by ink jetting, and the like can be given.

[0005] Above all, the method using laser light is superior to other methods in resolution and plate making speed.
There are many types.

[0006] The lithographic printing plate using the laser light is further classified into two types, a photon mode by a photoreaction and a heat mode by which photothermal conversion is performed to cause a thermal reaction.

As the photon mode type, (1) a high sensitivity PS plate using a photopolymer (2) an electrophotographic lithographic plate using an organic photoconductor or zinc oxide (3) a silver salt lithographic plate (4) a silver salt composite System lithography (5) Direct drawing master, etc., and the heat mode type includes (6) Thermal destruction system lithography.

[0008]

However, (1)
The method uses an argon ion laser as the laser light source, which makes the equipment large, and the printing plate uses high-sensitivity photopolymer. There is a drawback that the property is easily reduced.

The electrophotographic lithographic method (2) has an advantage that it can be handled in a bright room, but since the dark decay becomes large within 2 to 5 minutes after charging of the photosensitive layer, the exposure and development process is performed in a short time after charging. Therefore, it is difficult to output a large format with high resolution.

In the silver salt method (3), printing plates corresponding to lasers of various wavelengths have been developed. However, there is a problem that silver waste liquid comes out, and since the sensitivity is high, care must be taken when handling. There is also a problem that requires.

(4) The silver-salt composite lithographic plate is provided with a high-sensitivity silver halide emulsion layer on a photosensitive layer, exposing the upper silver halide emulsion layer with an argon ion laser, developing the resultant, and further using the mask as a mask for further ultraviolet irradiation. Exposure and development. However, since this printing plate has two exposure and development steps, there is a problem that the processing of the printing plate becomes complicated.

The direct drawing master (5) does not directly write on a printing plate with a laser, but transfers a toner image formed by a laser printer onto a printing plate as an ink-coated portion. However, the resolution of the printing plate is inferior to other methods.

For the above photon mode type,
The thermal destruction method (6) has an advantage that it can be handled in a bright room, and its usefulness has recently been reviewed due to rapid progress of the output of a semiconductor laser as a light source.

For example, US Pat. No. 5,379,698 describes a direct drawing type waterless planographic printing plate using a metal thin film as a heat-sensitive layer. However, since the metal thin film itself reflects laser light to some extent, the sensitivity of the printing plate is poor. There was such a problem. For this reason, in order to increase the absorption rate of the laser light, it is necessary to provide an antireflection layer, which further increases the coating process,
The result is costly.

Further, Japanese Patent Application Laid-Open No. 6-199064, USP
No. 5339737, US Pat. No. 5,353,705, EP05
No. 80393, JP-A-6-55723, EP0573
No. 091 and US Pat. No. 5,378,580 also describe a direct drawing type waterless planographic printing plate precursor using a laser beam as a light source.

The heat-sensitive layer of the printing plate precursor of this thermal destruction method is
Carbon black is used as the laser light absorbing compound, and nitrocellulose is used as the thermal decomposition compound.
This carbon black is converted into thermal energy by absorbing the laser beam, and the heat destroys the heat-sensitive layer.

Finally, by removing this portion by development, the silicone rubber layer on the surface is simultaneously peeled off to form an ink-coated portion.

This printing plate has a better laser beam absorptivity than the above-mentioned metal thin film, but it is still not sufficient, and there is a problem that the printing plate has low sensitivity.

The cause of this is that the amount of carbon black used in the heat-sensitive layer is small.

That is, in the above-mentioned patent, when the addition weight part of nitrocellulose is 1, the addition weight part of carbon black is 1 or less, so that the blackness of the printing plate does not increase, and therefore, The laser light is not efficiently absorbed. This results in a problem that the sensitivity of the printing plate does not increase.

Further, in particular, JP-A-6-55523, EP
No. 057391 and US Pat. No. 5,378,580 have another problem that the exposure apparatus becomes quite large because the light source is an Nd-YAG laser.

In order to ameliorate the above-mentioned drawbacks of the prior art, the present invention provides an added weight part of carbon black in the range of 1.1 or more relative to 1 nitrocellulose.
It is an object of the present invention to provide a direct drawing type waterless planographic printing plate which efficiently absorbs laser light and consequently has improved sensitivity.

[0023]

To achieve the above object, the present invention comprises the following constitution.

1. In a direct drawing type waterless planographic printing plate precursor in which a heat-sensitive layer containing carbon black and nitrocellulose and a silicone rubber layer were sequentially laminated on a substrate, the weight ratio of carbon black to nitrocellulose was 1 part of nitrocellulose. A direct drawing type waterless planographic printing plate precursor characterized by having carbon black of 1.1 or more.

2. 1. The direct drawing waterless lithographic printing plate precursor as described in 1 above, wherein the sum of the weight of carbon black and nitrocellulose in the heat-sensitive layer is 30% by weight to 90% by weight based on the total composition of the heat-sensitive layer.

3. In the above 1, the thickness of the heat sensitive layer was 0.
A direct drawing type waterless planographic printing plate precursor characterized by being ² to 3 g / m ² .

4. 1. The direct drawing type waterless lithographic printing plate precursor as described in 1 above, wherein the heat-sensitive layer is a heat-crosslinking type.

5. A waterless planographic printing plate obtained by selectively exposing and developing the direct drawing type waterless planographic printing plate precursor described in any one of 1 to 4 above.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, the direct drawing type means that an image is formed directly from a recording head on a printing plate without using a negative or positive film at the time of exposure.

Next, the direct drawing type waterless planographic printing plate used in the present invention will be explained.

It is important that the heat-sensitive layer used in the present invention efficiently absorbs laser light and is momentarily decomposed partially or entirely by the heat.

To this end, it is important that the heat-sensitive layer contains a photothermal conversion substance.

The compound is not particularly limited as long as it is a substance capable of absorbing light and converting it into heat, and for example, black pigments such as carbon black, aniline black and cyanine black, phthalocyanine and naphthalene. Phthalocyanine-based green pigment, carbon graphite, iron powder, diamine-based metal complex, dithiol-based metal complex, phenolthiol-based metal complex, mercaptophenol-based metal complex, arylaluminum metal salts, inorganic water-containing inorganic compound, copper sulfate, chromium sulfide , Silicate compounds, metal oxides such as titanium oxide, vanadium oxide, manganese oxide, iron oxide, cobalt oxide and tungsten oxide, hydroxides and sulfates of these metals, and further bismuth, tin, tellurium, iron and aluminum. It is preferable to add an additive such as the above metal powder.

Among these, carbon black is particularly preferable from the viewpoints of light-heat conversion rate, economy and handleability.

Carbon blacks are classified into furnace blacks, channel blacks, thermal blacks, acetylene blacks, lamp blacks, etc. according to their production methods, but various types of furnace blacks are commercially available in terms of particle size and the like. Since it is commercially available and inexpensive, it is preferably used.

The use of conductive carbon black also
It is effective for improving the sensitivity of the plate material.

The electric conductivity at this time is 0.01 Ω ^-1
It is preferably in the range of cm ^-1 ~100Ω ^-1 cm ^-1, more preferably 0.1Ω ^-1 cm ^-1 ~10Ω ^-1
cm- ¹ .

Specifically, "CONDUCTEX" 40
-220, "CONDUCTEX" 975 BEADS,
"CONDUCTEX" 900 BEADS, "COND
UCTEX "SC," BATTERY BLACK "
(Colombian carbon Japan (manufactured by Japan)), # 3000 (manufactured by Mitsubishi Kasei Co., Ltd.) and the like are more preferably used.

The amount of these light-heat converting substances added is preferably 2-70% by weight, more preferably 5-60% by weight, based on the total heat-sensitive layer composition.

If the addition amount is less than 2% by weight, the effect of improving the sensitivity is not observed, and if it is more than 70% by weight, the printing durability of the printing plate tends to be deteriorated.

It is important that the heat-sensitive layer is instantaneously decomposed partially or entirely by the heat generated by the photothermal conversion substance.

As the compound satisfying the easily heat decomposable property,
Nitro compounds such as ammonium nitrate, potassium nitrate, sodium nitrate and nitrocellulose, organic peroxides, azo compounds, diazo compounds and hydrazine derivatives are preferably used.

Among these, nitrocellulose is a polymer, so it has an appropriate viscosity in a solution state, and since it has a hydroxyl group in the molecule, it has an adhesive property with the silicone rubber layer. It is particularly preferable because it becomes good. The nitrocellulose used here is not for explosives, but is preferably industrial nitrocellulose.

The amount of nitrocellulose used is preferably 10 to 80% by weight, more preferably 20 to 60% by weight, based on the total heat-sensitive layer composition. If the amount used is less than 10% by weight, the sensitivity of the printing plate is reduced, and 80% by weight.
If it is larger than this, the solvent resistance of the printing plate tends to decrease.

Since these carbon blacks are used in combination with nitrocellulose, the ratio of the amount added is very important.

That is, if the amount of carbon black added to nitrocellulose is too large or too small, a proper printing plate cannot be obtained.

It is important that the weight ratio of carbon black is 1.1 or more relative to 1 of nitrocellulose, preferably 1.1 to 3 and more preferably 1.1 to.
2.

If the weight ratio is less than 1.1, the sensitivity of the printing plate tends to decrease because the laser light is not efficiently absorbed, and if the weight ratio is too large, the printing durability of the printing plate deteriorates. Cheap.

Furthermore, the sum of the weights of carbon black and nitrocellulose is 30% by weight based on the total heat-sensitive layer composition.
It is preferably between about 90% by weight. It is more preferably 30% by weight to 70% by weight, and further preferably 40% by weight to 60% by weight.

When the sum of the weights is less than 30% by weight, the sensitivity of the printing plate tends to decrease, and when it exceeds 90% by weight,
The solvent resistance of the printing plate tends to decrease.

Examples of organic peroxides include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxyesters and peroxydicarbonates.

It is also effective to add a thermal decomposition aid such as urea and urea derivatives, zinc white, lead carbonate, lead stearate and glycolic acid.

The amount of these thermal decomposition aids added is preferably 0.02 to 10% by weight, more preferably 0.1 to 5% by weight, based on the total photosensitive layer composition.

These heat-sensitive layers need to have a crosslinked structure in order to enhance solvent resistance to printing ink.

The cross-linking method includes a thermal cross-linking type and a photo-crosslinking type. However, since the heat-sensitive layer in the present invention has poor light transmittance,
Since the reaction does not proceed sufficiently with photocrosslinking, a thermal crosslinking type is preferred.

The polyfunctional crosslinking agent used for introducing the crosslinked structure includes a polyfunctional isocyanate compound or a polyfunctional epoxy compound, a urea compound, an amine compound, a hydroxyl group-containing compound, a carboxylic acid compound and a thiol compound. Combinations with compounds are mentioned.

However, when a polyfunctional isocyanate compound is used, the reaction is not completed in a short time, so it is necessary to cure at a high temperature. However, since the decomposition temperature of nitrocellulose is 180 ° C., a temperature higher than that is required. I can't cure.

Therefore, the reaction gradually progresses even after the printing plate is prepared, which may adversely affect the developability of the printing plate.

Therefore, the crosslinking method is preferably a combination of a polyfunctional epoxy compound with an amine compound, an amide compound, a hydroxyl group-containing compound, a carboxylic acid compound or a thiol compound.

Examples of polyfunctional epoxy compounds include bisphenol A type epoxy resins, bisphenol F type epoxy resins, and glycidyl ether type epoxy resins.

Examples of the amine compound include butylated urea resin, butylated melamine resin, butylated benzoguanamine resin, butylated urea melamine cocondensation resin, aminoalkyd resin, iso-butylated melamine resin, methylated melamine resin, hexamethoxy. Methylol melamine, methylated benzoguanamine resin, butylated benzoguanamine resin, diethylenetriamine, triethylenetriamine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, metaxylylenediamine, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, Isophorone diamine, etc.

Examples of the amide compound include a polyamide curing agent used as a curing agent for epoxy resin and dicyandiamide. Examples of the hydroxyl group-containing compound include phenol resin and polyhydric alcohol. There are valent thiols.

As the carboxylic acid compound, phthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid, dodecynylsuccinic acid, pyromellitic acid, chlorenic acid, maleic acid, fumaric acid and their anhydrides are preferably used.

In these cases, a quaternary ammonium salt, KOH or SnC is used as a catalyst for promoting the reaction.
It is preferable to use a known catalyst such as l ₄ , Zn (BF ₄ ) _{2 or} an imidazole compound.

Among the above-mentioned cross-linking agents, a combination of a polyfunctional epoxy compound and an amine compound is more preferable in view of curing rate and handleability.

Further, a polyfunctional crosslinking agent having an organic silyl group and an amino group-containing monomer can also be preferably used.

The amount of these polyfunctional crosslinking agents used is preferably 1 to 50% by weight, more preferably 3 to 40% by weight, based on the total heat-sensitive layer composition. If it is less than 1% by weight, the solvent resistance of the printing plate tends to decrease, and
If it is larger than this, the printing plate becomes hard and the printing durability tends to decrease.

The heat-sensitive layer preferably contains a binder polymer for the purpose of improving printing durability and storage stability. The polymer used at this time is
Polymer used in the primer, namely, polyurethane resin, phenol resin, acrylic resin, alkyd resin, polyester resin, vinyl chloride-vinyl acetate copolymer, vinyl chloride resin, polyvinyl butyral resin, ethylene-vinyl acetate copolymer, Polycarbonate resin, polyacrylonitrile-butadiene copolymer, polyether resin, polyether sulfone resin, milk casein, gelatin and carboxymethyl cellulose, cellulose acetate, cellulose propyl acetate, cellulose butyl acetate, cellulose triacetate,
Hydroxypropyl cellulose ether, ethyl cellulose ether, cellulose derivative such as cellulose phosphate, polyvinyl acetate, polystyrene, polystyrene-acrylonitrile copolymer, polysulfone, polyphenylene oxide, polyethylene oxide, polyvinyl alcohol-acetal copolymer, polyvinyl acetal, polyvinyl alcohol -Polyacetal copolymer, polyvinyl alcohol-polybutyral copolymer,
Examples thereof include polyvinyl benzal, polyvinyl alcohol, ethylene maleic anhydride copolymer, chlorinated polyolefin such as chlorinated polyethylene, chlorinated polypropylene, and the like. Among them, cellulose derivatives such as cellulose acetate and polyvinyl chloride-vinyl acetate copolymer. Chlorine-containing copolymers such as ethylene-vinyl acetate copolymers, polyurethane resins and acrylic resins are preferably used.

In addition to the above-mentioned thermally decomposable compounds, polyacetylene, polyaniline and the like which are known as conductive polymers are also preferably used.

The content of these binder polymers is
The amount is preferably 10 to 60% by weight, more preferably 20 to 50% by weight, based on the total heat-sensitive layer composition. If the content is less than 10% by weight, printing durability tends to decrease, and 60
If it exceeds 5% by weight, the sensitivity tends to decrease.

Further, the heat-sensitive layer may appropriately contain additives such as antiseptics, antihalation dyes, defoamers, antistatic agents, dispersants, emulsifiers and surfactants.

Particularly, it is preferable to add a fluorine-containing surfactant in order to improve the coating property. The addition amount of these additives is usually 10% by weight or less based on the total heat-sensitive layer composition.

Further, in some cases, in order to enhance the adhesiveness with the silicone rubber layer, silica powder or hydrophobic silica powder whose surface is treated with a silane coupling agent containing a (meth) acryloyl group or an allyl group is subjected to a total heat-sensitive treatment. It may be added in an amount of 20% by weight or less based on the layer composition.

The composition for forming the above heat sensitive layer is
DMF, methyl ethyl ketone, methyl isobutyl ketone, dioxane, toluene, xylene, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethylene glycol monomethyl ether,
Ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, acetone, methyl alcohol, ethyl alcohol, cyclopentanol, cyclohexanol, diacetone alcohol, benzyl alcohol, butyl butyrate,
It is prepared as a composition solution by dissolving it in a suitable organic solvent such as ethyl lactate. Such a composition solution is uniformly applied on a substrate and heated at a required temperature for a required time to form a heat-sensitive layer.

It is necessary to carry out the heat curing at a temperature within which the nitrocellulose, which is a thermally decomposable compound, is not decomposed, usually at 180 ° C. or lower. For this reason, it is preferable to use the above catalyst in combination.

The thickness of these heat-sensitive layers is preferably 0.1 g / m ² to 10 g / m ² , and more preferably 0.2 g / m ^2.
m ² to 3 g / m ² , more preferably 0.5 g
/ M ² to 2 g / m ² . When the film thickness is less than 0.1 g / m ^2, printing durability tends to decrease,
^{When the} thickness is more than ² , the above range is particularly preferable because the heat-sensitive layer is not completely decomposed during exposure.

As the substrate of this printing plate, a dimensionally stable plate is used. Such dimensionally stable plate-like objects include those conventionally used as substrates for printing plates, and they can be suitably used. Such substrates include paper, plastic (eg, polyethylene,
Paper laminated with polypropylene, polystyrene, etc., such as aluminum (including aluminum alloys), metal plates such as zinc, copper, etc., such as cellulose, carboxymethyl cellulose, cellulose acetate, polyethylene terephthalate, polyethylene. , Polyester, polyamide, polyimide, polystyrene,
A film of a plastic such as polypropylene, polycarbonate, polyvinyl acetal, etc., a paper or a plastic film on which a metal such as the above is laminated or vapor-deposited are included. Of these substrates,
Aluminum plates are particularly preferred because they are extremely dimensionally stable and inexpensive. Further, a polyethylene terephthalate film used as a substrate for light printing is also preferably used.

The waterless planographic printing plate used in the present invention may be provided with a primer layer in order to strengthen the adhesion between the substrate and the photosensitive layer. The primer layer of the direct drawing type waterless planographic printing plate precursor used in the invention is required to satisfy the following conditions. That is, the substrate and the photosensitive layer are well adhered to each other, are stable over time, and have good solvent resistance to the solvent of the developing solution. As a material satisfying such a condition, in addition to a material containing an epoxy resin as shown in Japanese Patent Publication No. 61-54219, a polyurethane resin,
Phenol resin, acrylic resin, alkyd resin, polyester resin, polyamide resin, melamine resin, urea resin, benzoguanamine resin, vinyl chloride-vinyl acetate copolymer, vinyl chloride resin, polyvinyl butyral resin,
Ethylene-vinyl acetate copolymer, polycarbonate resin, polyacrylonitrile-butadiene copolymer, polyether resin, polyether sulfone resin, milk casein, gelatin and the like can be used. These resins may be used alone or in combination of two or more.

Further, a composition similar to that of the heat-sensitive layer, which is light- or heat-cured, may be used.

Of these, polyurethane resins, polyester resins, acrylic resins, epoxy resins, urea resins and the like are preferably used alone or in admixture of two or more.

As the anchor agent constituting the primer layer, a known adhesive such as a silane coupling agent can be used, and organic titanate is also effective.

It is also optional to add a surfactant for the purpose of improving the coatability.

In the exposed area of the printing plate, the primer layer is exposed and becomes an image area. Therefore, it is preferable to add an additive such as a dye to the primer layer to improve the plate inspection property.

The composition for forming the above-mentioned primer layer is prepared as a composition solution by dissolving it in a suitable organic solvent such as DMF, methyl ethyl ketone, methyl isobutyl ketone, dioxane, toluene, xylene and THF. A primer layer is formed by uniformly applying the composition solution on a substrate and heating it at a required temperature for a required time.

The thickness of the primer layer is 0.5 as a coating layer.
~ 50 g / m ² is preferred, more preferably 1-10.
g / m ² . When the thickness is less than 0.5 g / m ² , the effect of blocking morphological defects and chemical adverse effects on the surface of the substrate is reduced, and when it is more than 50 g / m ^2, it is disadvantageous from the economical point of view, so the above range is preferable.

As the silicone rubber layer, all conventional silicone compositions for waterless lithographic printing plates can be used.

Such a silicone rubber layer is obtained by sparsely cross-linking a linear organopolysiloxane (preferably dimethylpolysiloxane), and a typical silicone rubber layer has the following formula (I). It has a repeating unit as shown in.

[0088]

Embedded image (Here, n is an integer of 2 or more. R has 1 to 10 carbon atoms.)
Alkyl, aryl, or cyanoalkyl group. Preferably, 40% or less of the whole R is vinyl, phenyl, vinyl halide, or halogenated phenyl, and 60% or more of R is a methyl group. Further, it has at least one or more hydroxyl group in the molecular chain at the chain end or in the form of a side chain. In the case of the silicone rubber layer applied to the printing plate of the present invention, a silicone rubber (R
TV, LTV type silicone rubber). As such a silicone rubber, R of an organopolysiloxane chain is used.
Although a part of H may be substituted with H, it is usually crosslinked by condensation of the terminal groups represented by the following formulas (II), (III) and (IV). In some cases, an excess of a crosslinking agent may be present.

[0089]

Embedded image

Embedded image

Embedded image (Where R is the same as R described above; R1, R2
Is a monovalent lower alkyl group, and Ac is an acetyl group. ) Silicone rubber which performs such condensation type crosslinking includes:
A metal carboxylate such as tin, zinc, lead, calcium, or manganese, for example, dibutyltin laurate, tin (II) octoate, naphthenate, or a catalyst such as chloroplatinic acid is added.

In addition to these compositions, a known adhesiveness-imparting agent such as alkenyltrialkoxysilane may be added, or a hydroxyl group-containing organopolysiloxane or a hydrolyzable functional group which is a composition of the condensation type silicone rubber layer. It is optional to add a group-containing silane (or siloxane), and it is also optional to add a known filler such as silica for the purpose of improving rubber strength.

The thickness of these silicone rubber layers is 0.5.
To 50 g / m ² , more preferably 0.5 to 50 g / m ^2.
10 g / m ² . When the film thickness is less than 0.5 g / m ² , the ink repellency of the printing plate tends to decrease, and
If it is larger than g / m ² , it is disadvantageous from an economic point of view.

For the purpose of protecting the heat-sensitive layer on the surface of the waterless lithographic printing plate precursor constructed as described above, a thin protective film having a plane or a roughened surface is laminated on the surface of the heat-sensitive layer. Or Japanese Patent Laid-Open No. 5-32358
It is also possible to form a coating film of a polymer that can be dissolved in the developing solvent described in JP-A No. 8 (1996) -108.

In particular, when a protective film is laminated, laser exposure is performed on the protective film, and then the protective film is peeled off to form a pattern on the printing plate. It is also possible to create.

Next, the method for producing a waterless planographic printing plate according to the present invention will be described. An ordinary coater such as a reverse roll coater, an air knife coater, and a Mayer bar coater or a spin coater such as a whaler was applied on the substrate, and the primer layer composition was applied if necessary and cured at 100 to 300 ° C. for several minutes. Then, a heat-sensitive layer composition coating liquid is applied, dried at a temperature of 50 to 180 ° C. for several minutes, and thermally cured if necessary, a silicone rubber composition is applied, and heat treated at a temperature of 50 to 150 ° C. for several minutes to give a rubber. It is formed by curing.

Then, a protective film is laminated or a protective layer is formed, if necessary.

The direct drawing type waterless planographic printing plate precursor thus obtained is imagewise exposed with a laser beam after peeling off the protective film or on the protective film.

A laser beam is usually used for the exposure, and the light source at this time has an oscillation wavelength of 300 nm to 1500.
such as Ar ion laser, Kr ion laser, He-Ne laser, He-Cd laser, ruby laser, glass laser, semiconductor laser, YAG laser, titanium sapphire laser, dye laser, nitrogen laser, metal vapor laser in the range of nm. Various lasers can be used. Among them, the semiconductor laser is preferable because it is miniaturized due to the recent technical progress and is economically advantageous over other laser light sources.

The direct drawing type waterless planographic printing plate exposed by the above-mentioned method is subjected to peeling development or usual solvent development treatment, if necessary.

The developing solution used in the present invention includes, for example, water, one obtained by adding the following polar solvent to water, and aliphatic hydrocarbons (hexane, heptane, “Isopar E,
G, H "(trade names of isoparaffinic hydrocarbons manufactured by ESSO), gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, xylene, etc.), and halogenated hydrocarbons (trichlene, etc.). A mixture obtained by adding at least one of the following polar solvents to a mixed solvent is preferably used.

Alcohols (methanol, ethanol,
Propanol, isopropanol, ethylene glycol, diethylene glycol, triethylene glycol,
Polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,3-butylene glycol,
2,3-butylene glycol, hexylene glycol,
2-ethyl-1,3-hexanediol, etc.) Ethers (ethylene glycol monoethyl ether,
Diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, diethylene glycol mono-2
-Ethylhexyl ether, triethylene glycol monoethyl ether, tetraethylene glycol monoethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, dioxane, tetrahydrofuran, etc. Ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone) , Diacetone alcohol, etc. Esters (ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, butyl lactate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, etc.) Acid (2-ethylbutyric acid, Prong acid, caprylic acid, 2-ethylhexanoic acid, capric acid, oleic acid,
In addition, a known surfactant can be freely added to the above-mentioned developer composition. In addition, further alkaline agent,
For example, sodium carbonate, monoethanolamine, diethanolamine, diglycolamine, monoglycolamine, triethanolamine, sodium silicate, potassium silicate, potassium hydroxide, sodium borate and the like can be added.

Further, well-known basic dyes such as crystal violet, Victor Pure Blue, Astrazone Red, acid dyes and oil-soluble dyes may be added to these developers to dye the image area at the same time as development. You can

When developing, these developing solutions may be impregnated in a non-woven fabric, absorbent cotton, cloth, sponge or the like, and the plate surface may be wiped off to develop.

For development, Japanese Patent Laid-Open No. 63-163357.
It is possible to suitably develop by pretreatment of the plate surface with the above-mentioned developing solution using an automatic developing machine as described in 1) and then rubbing the plate surface with a rotating brush while showering with tap water or the like.

Development can also be performed by spraying hot water or steam onto the plate surface instead of the above developing solution.

[0105]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

In this embodiment, blackness means Vulcan X.
When a plate was prepared using C-72 (Comparative Example 3), the degree of blackness was visually evaluated as 3 in 5 grades, and the blackest one was defined as 5.

Examples 1 to 6 and Comparative Examples 1 to 3 A primer solution having the following composition was applied on a degreased aluminum plate having a thickness of 0.24 mm, dried at 230 ° C. for 1 minute, and 3 g / m ² Was provided.

(A) Cancoat 90T-25-3094 (Epoxy phenol resin manufactured by Kansai Paint Co., Ltd.) 15 parts by weight (b) Victoria Pure Blue BOH naphthalene sulfonic acid 0.1 part by weight (c) 85 parts by weight of dimethylformamide Then, a heat-sensitive layer composition having the following composition was coated on this photosensitive layer and dried at 130 ° C. for 1 minute to form a heat-sensitive layer having a film thickness of 2 g / m ² .

(A) Nitrocellulose (viscosity 1/2 second, nitrogen content 11.0% “Berge rac NC” manufactured by SNP Japan Co., Ltd.) (Table 1) (b) Carbon black ( Table 1) (c) 30 parts by weight of polyester resin (“Vylon 300”, manufactured by Toyobo Co., Ltd.) (d) 15 parts by weight of modified epoxy resin (“Epokey” 803, manufactured by Mitsui Toatsu Chemicals, Inc.) (e) Diethylenetriamine 5 parts by weight (f) Methyl isobutyl ketone 600 parts by weight Subsequently, a silicone having the following composition on the primer layer.
Apply a rubber solution and dry for 2 minutes at 120 ° C to a thickness of 3
A silicone rubber layer of g / m ² was provided.

(A) Polydimethylsiloxane (molecular weight about 35,000, terminal hydroxyl group) 100 parts by weight (b) Ethyltriacetoxysilane 12 parts by weight (c) Dibutyltin diacetate 0.1 parts by weight (d) "Isopar" G "(manufactured by Exxon Chemical Co., Ltd.) 1200 parts by weight The laminated plate obtained as described above is laminated with a polyester film" Lumirror "(manufactured by Toray Co., Ltd.) having a thickness of 8 μm using a calendar roller, A direct drawing type waterless planographic printing plate precursor was obtained.

After that, the "lumirror" of the printing plate precursor was peeled off, and the semiconductor laser (SL) mounted on the XY table was peeled off.
D-304XT, output 1 W, wavelength 809 nm, manufactured by Sony Corporation), beam diameter 20 μm, exposure time 1
Pulse exposure was performed at 0 μs. At this time, the laser output is L
The laser power on the printing plate was measured by arbitrarily changing it with a D pulse modulation driving device, and the sensitivity was calculated.

Subsequently, rubbing with a cotton pad impregnated with a developing solution having the following composition was carried out to develop.

(A) 80 parts by weight of water (b) 20 parts by weight of diethylene glycol mono-2-ethylhexyl ether The image reproducibility of this printing plate was evaluated with a magnifying power of 50 times to determine the minimum laser power for forming dots. Then, the sensitivity of the printing plate was measured from the result.

As shown in Table 1, it can be seen that the sensitivity is lowered when the addition ratio of carbon black and nitrocellulose is out of the specified range.

[0115]

[Table 1]

[0116]

The direct drawing type waterless planographic printing plate of the present invention has improved sensitivity as compared with the conventional direct drawing type waterless planographic printing plate.

Claims (5)

[Claims] 1. A direct drawing type waterless planographic printing plate precursor in which a heat-sensitive layer containing carbon black and nitrocellulose and a silicone rubber layer are sequentially laminated on a substrate, and the weight ratio of carbon black and nitrocellulose is nitro. A direct drawing type waterless planographic printing plate precursor characterized in that carbon black is 1.1 or more relative to cellulose 1. 2. The direct drawing type waterless composition according to claim 1, wherein the total weight of carbon black and nitrocellulose in the heat-sensitive layer is 30% by weight to 90% by weight based on the total heat-sensitive layer composition. Original planographic printing plate. 3. The heat sensitive layer according to claim 1, wherein the film thickness is 0.2.
A direct drawing type waterless planographic printing plate precursor characterized in that it is ~ 3 g / m ² . 4. A direct drawing type waterless planographic printing plate precursor according to claim 1, wherein the heat-sensitive layer is a heat-crosslinking type. 5. A direct drawing type waterless planographic printing plate precursor according to claim 1, which is selectively exposed and developed.
Waterless planographic printing plate.