JPH09131979A - Direct drawing type waterless lithographic printing original plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve resistance to printing by incoporating nitrocellulose containing nitrogen of specified amount in a heat-sensitive layer and increasing the number of hydroxyl groups relating to the bonding reaction when a direct drawing type waterless lithographic original plate is constituted by laminating successively the heat-sensitive layer and a silicone rubber layer on a base. SOLUTION: When a direct drawing type waterless lithographic original plate is constituted by laminating successively a heat-sensitive layer and a seilicone rubber layer on a base, nitrogen of 11.5% or less, more preferably 6.8%-11.5%, is contained in the heat-sensitive layer. When the nitrogen content amount is less than 6.8%, the sensitivity of printing degree is lowered, and also the solubility to a solvent is lowered easily, while when larger than 11.5%, the number of hydroxyls is reduced, and the bonding properties with the silicone layer as an upper layer get weak, and as a result, resistance to printing is lowered. Resistance to printing 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 also discloses 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 absorption rate of laser light than the above-mentioned metal thin film, but since these printing plates have a weak adhesive force between the silicone rubber layer and the heat sensitive layer on the surface, they are scratched during printing. However, there is a problem in that the printing durability is low due to the inclusion of paper.

The first reason is that the nitrocellulose, which is the main polymer of the heat-sensitive layer, is used in the RS type, that is, the type having a high nitrogen content of 11.8%, so the number of hydroxyl groups decreases, This was because it was difficult to form a chemical bond with the upper layer silicone rubber.

The second reason is that the silicone used is an addition type silicone. That is, since the addition type silicone has almost no functional group involved in the adhesive reaction with the heat sensitive layer, the adhesive force is weakened.

Further, JP-A-6-55723 and EP05.
No. 73091 also describes a direct drawing type waterless planographic printing plate in a similar manner.

However, also in this case, since the silicone used is an addition type silicone, there is a problem that the adhesive force between the silicone rubber layer and the heat sensitive layer is weakened and the printing durability is low. It was

The laser used is Nd-YA.
Since it is a G laser, there is another problem that the exposure apparatus becomes quite large.

In order to remedy the drawbacks of the prior art, the present invention uses a nitrocellulose having a low nitrogen content of 11.5% or less to increase the number of hydroxyl groups involved in the adhesion reaction and to improve the resistance. It is an object to provide a direct drawing type waterless planographic printing plate having improved printability.

[0025]

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

1. A direct drawing type waterless planographic printing plate precursor in which a heat-sensitive layer and a silicone rubber layer are sequentially laminated on a substrate, wherein the heat-sensitive layer contains nitrocellulose having a nitrogen content of 11.5% or less. Original waterless planographic printing plate.

2. 1. The direct drawing type waterless planographic printing plate precursor as described in 1 above, wherein the heat-sensitive layer contains a photothermal conversion substance.

3. 1. The direct drawing type waterless lithographic printing plate precursor as described in 1 above, wherein the heat-sensitive layer contains carbon black.

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.

[0031]

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.

The nitrogen content is the ratio of the atomic weight of nitrogen to the molecular weight of nitrocellulose, and is an index showing the degree of nitration. That is, the higher the nitrogen content, the higher the degree of nitration.

The nitrogen content can be calculated by the following formula. Alternatively, it can be determined by elemental analysis.

[0034]

(Equation 1) The nitrocellulose used here is not for explosives, but is preferably industrial nitrocellulose.

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

The heat-sensitive layer used in the present invention must be partially or wholly decomposed by heat to have good adhesiveness with the silicone layer and be tough.

Among the above-mentioned conditions, as the compound satisfying the thermal decomposition property, a nitro compound such as ammonium nitrate, potassium nitrate, sodium nitrate and nitrocellulose, an organic peroxide, an azo compound, a diazo compound or a hydrazine derivative is preferably used. .

Among these, nitrocellulose is particularly preferable because it is a polymer and therefore has an appropriate viscosity in a solution state, and therefore the coatability to a primer layer or a substrate becomes good.

Further, nitrocellulose is JIS K-6.
It has a hydroxyl group as defined by 703, and this hydroxyl group acts extremely effectively on the adhesiveness to the silicone layer.

This is because nitrocellulose is a linear polymer and D-glucose, which is a repeating unit, contains at most 3 hydroxyl groups, so that a condensation reaction occurs at the interface with the silicone rubber layer, This is because it is effective in terms of adhesiveness.

The nitrogen content of nitrocellulose is regulated by the degree of substitution of the nitro group, and when all three hydroxyl groups are replaced by nitro groups, the nitrogen content becomes 14.1% and only one is nitrated. Nitrogen content is 6.8%
Becomes

That is, the higher the nitrogen content, the lower the number of hydroxyl groups in the molecule and the lower the adhesion to the silicone layer.

Therefore, in the present invention, the nitrogen content is preferably 11.5% or less, more preferably 6.8% to 11.5%.

When the nitrogen content is less than 6.8%, the sensitivity of the printing plate is lowered, and the solubility in a solvent is apt to be lowered, and when it exceeds 11.5%, the number of hydroxyl groups is reduced. However, the adhesiveness with the upper silicone layer is weakened, and as a result, the printing durability is lowered.

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 more than the above range, the solvent resistance of the printing plate is deteriorated.

Examples of the organic peroxide include ketone peroxide, peroxyketal, hydroperoxide,
Dialkyl peroxide, diacyl peroxide,
Examples include peroxyesters and peroxydicarbonates.

It is preferable to contain a photothermal conversion substance in order to cause a thermal decomposition reaction efficiently when the above thermal decomposition compound is irradiated with laser light.

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, water-containing inorganic compounds, 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, 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, economical efficiency and handleability.

Carbon blacks are classified into furnace blacks, channel blacks, thermal blacks, acetylene blacks, lamp blacks, etc. according to their manufacturing 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 amount of these photothermal conversion substances used is preferably 2 to 70% by weight, more preferably 5 to 60% by weight, based on the total heat-sensitive layer composition. When it is less than 2% by weight, the sensitivity of the printing plate tends to decrease, and when it is more than 70% by weight, the printing durability of the printing plate tends to decrease.

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 preferably have a crosslinked structure in order to improve 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.

Due to the above-mentioned restrictions, the crosslinking method is a combination of crosslinking agents that proceed at a temperature as low as possible and are stable at room temperature, such as amine-based compounds, amide-based compounds, and hydroxyl-containing compounds for polyfunctional epoxy compounds. A combination of a compound, a carboxylic acid compound and a thiol compound is preferable.

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 introduced into the molecular chain thereof to improve the adhesiveness with the upper silicone layer can 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 5 g / m ² . When the film thickness is less than 0.1 g / m ^2, printing durability tends to decrease, and when the film thickness is 10 g / m ²
When it is thicker than the above range, 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,
Examples include plastic films such as polypropylene, polycarbonate and polyvinyl acetal, and paper or plastic films in which the above substrate is metal-laminated or vapor-deposited. Among these substrates, the aluminum plate is particularly preferable because it is extremely stable in dimension 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 possible to improve the plate inspection property by adding an additive such as a dye in the primer layer. is there.

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 addition-type and condensation-type silicone rubber compositions which have been used in conventional waterless lithographic printing plates can be used, but in consideration of the adhesiveness to the heat-sensitive layer, A condensation type silicone having a reactive group with the heat sensitive layer is more preferable.

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, it is 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.

Synthesis Examples 1 to 6 50 ml of concentrated sulfuric acid was placed in a 200 ml Erlenmeyer flask, and 50 ml of fuming nitric acid was gradually added to this via a glass rod, and when the addition was completed, the mixture was cooled with water to prepare a mixed acid.

1 g of absolutely dried cellulose sample (fibrous, manufactured by Nacalai Tesque, Inc.) was precisely weighed, then added little by little to the mixed acid and stirred at room temperature for a predetermined time.

After completion of stirring, the reaction product was filtered through a glass filter, washed with ice-cold water three times, finally washed with methanol, and dried in a dryer at 50 ° C., and then the obtained nitrocellulose was purified. Weigh. (Compounds 1 to 6) Given that the weight of the nitrocellulose obtained at this time is x (g), the nitrogen content (%) is calculated by substituting in the following formula 31.1 x (1-1 / x). To be done. (Table 1) Examples 1 to 4 and Comparative Examples 1 to 2 An aluminum plate having a thickness of 0.15 mm (manufactured by Sumitomo Metal Co., Ltd.) was coated with the following primer composition using a bar coater, Two
Heat treatment was performed at 20 ° C. for 2 minutes to provide a primer layer of 5 g / m ² .

(A) 90 parts by weight of polyurethane resin (Samprene LQ-T1331, manufactured by Sanyo Kasei Co., Ltd.) (b) 15 parts by weight of block isocyanate (Takenate B830, manufactured by Takeda Pharmaceutical Co., Ltd.) c) Epoxy phenol urea resin (SJ9372, manufactured by Kansai Paint Co., Ltd.) 8 parts by weight (d) Tetraglycerol dimethacrylate 0.2 parts by weight (e) Dimethylformamide 725 parts by weight The following heat-sensitive layer composition was applied using a bar coater and dried in hot air at 140 ° C. for 1 minute to give a film thickness of 3 g.
A heat-sensitive layer of / m ² was provided.

(A) Nitrocellulose (Compounds 1 to 6, Table 1) 25 parts by weight (b) Copper phthalocyanine (manufactured by Nacalai Tesque, Inc.) 2 parts by weight (c) Carbon black "RAVEN1255" (Colombian Carbon Japan ( 15 parts by weight (d) Epoxy resin “Denacol” EX512 (manufactured by Nagase Kasei Co., Ltd.) 50 parts by weight (e) Urea resin “Beckamine” P-138 10 parts by weight (f) Methyl ethyl ketone 700 parts by weight 1. A silicone rubber composition having the following composition was spin-coated on this heat-sensitive layer, and then 115 ° C., dew point 30 ° C., and 3.
It was heat-cured for 5 minutes to provide a 2 g / m ² silicone rubber layer.

(A) Polydimethylsiloxane (molecular weight of about 25,000, terminal hydroxyl group) 100 parts by weight (b) Vinyltri (methylethylketoxime) silane 8 parts by weight (c) "Isopa-E" (manufactured by Exxon Chemical Co., Ltd.) 1400 parts by weight A semiconductor laser (OPC-A001-mmm-FC, output 0.75, in which the printing original plate was mounted on an XY table.
W, wavelength 780nm, OPTO POWERCORPO
(Ratio manufactured), pulse exposure was performed at a beam diameter of 20 μm and an exposure time of 10 μs.

Next, the above exposed plate is developed using TWL1160 (developing device for waterless planographic printing plate manufactured by Toray Industries, Inc., processing speed 100 cm / min) under conditions of room temperature of 25 ° C. and humidity of 80%. It was Here, water was used as the developing solution. A liquid having the following composition was used as the dyeing liquid.

(A) Ethyl carbitol 18 parts by weight (b) Water 79.9 parts by weight (c) Crystal violet 0.1 part by weight (d) 2-Ethylhexanoic acid 2 parts by weight The image reproducibility of this printing plate was evaluated. Evaluation was performed with a magnifying power of 50 to determine the minimum laser power at which dots were formed, and the sensitivity of the printing plate was measured from the result.

Further, this printing plate was mounted on an offset printing machine, and printing was performed using "Dryocolor" ink, indigo, red, and yellow ink manufactured by Dainippon Ink and Chemicals, Inc. The printing durability was evaluated.

As shown in Table 1, it can be seen that when the nitrogen content of nitrocellulose is 11.5% or more, the printing durability of the printing plate is extremely reduced.

[0116]

[Table 1]

[0117]

As described above, the direct drawing type waterless planographic printing plate of the present invention has improved printing durability 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 and a silicone rubber layer are sequentially laminated on a substrate, wherein the heat sensitive layer contains nitrocellulose having a nitrogen content of 11.5% or less. Direct drawing type waterless planographic printing plate precursor characterized by. 2. A direct drawing type waterless lithographic printing plate precursor as claimed in claim 1, wherein the heat sensitive layer contains a photothermal conversion substance. 3. A direct drawing type waterless lithographic printing plate precursor as claimed in claim 1, wherein the heat sensitive layer contains carbon black. 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 waterless lithographic printing plate obtained by selectively exposing and developing the direct drawing type waterless lithographic printing plate precursor as claimed in any one of claims 1 to 4.