JP3496370B2 - Direct drawing type waterless planographic printing plate precursor - Google Patents

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 that can be printed without using a fountain solution, and more particularly to a direct drawing type waterless planographic printing plate precursor that can be directly plate-made by laser light. It is a thing.

[0002]

2. Description of the Related Art The so-called direct plate making, in which an offset printing plate is directly produced from an original without using a plate making film, is simple without requiring skill, quick in obtaining a printing plate in a short time, and various Taking advantage of features such as rationality that can be selected from the system according to quality and cost,
Not only in the light printing industry, but also in the fields of general offset printing and gravure printing.

In particular, recently, various types of lithographic printing materials of a new type have been developed due to rapid progress of output systems such as prepress systems, imagesetters and laser printers.

These lithographic printing plates are classified according to the plate making method: a method of irradiating with a laser beam, a method of writing with a thermal head, a method of partially applying a voltage with a pin electrode,
Examples thereof include a method of forming an ink repellent layer or an ink inking layer by inkjet.

Among them, the method using laser light is superior to other methods in terms of resolution and plate making speed,
There are many types.

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

As the photon mode type (1) High-sensitivity PS plate using photopolymer (2) Electrophotographic planographic printing plate using organic photoconductor or zinc oxide (3) Silver salt method planographic printing (4) Silver salt composite method planographic printing (5) Direct drawing master As a heat mode type, (6) Thermal destruction method planographic printing Is mentioned.

[0008]

[Problems to be Solved by the Invention] However, (1)
In this method, the apparatus is large because it mainly uses an argon ion laser as the laser light source, and because the printing plate also uses a high-sensitivity photopolymer, care must be taken when handling the printing plate and storage stability is required. There is a drawback that the property is likely to deteriorate.

The electrophotographic planographic printing plate of (2) has an advantage that it can be handled in a bright room, but dark decay becomes large between 2 and 5 minutes after charging of the photosensitive layer, so that exposure and development processing is carried out in a short time after charging. It is difficult to output large format with high resolution.

With respect to the silver salt method (3), a printing plate compatible with lasers of various wavelengths has been developed, but it has a problem that silver waste liquid is discharged, and its sensitivity is high, so handle it carefully. There is also a problem that requires.

In the silver salt composite type lithographic plate of (4), a high-sensitivity silver halide emulsion layer is provided on the photosensitive layer, the upper silver halide emulsion layer is exposed with an argon ion laser, and after development, ultraviolet rays are further used as a mask. Exposure and development are performed. However, since this printing plate has two exposure and development steps, there is a problem that the processing of the printing plate becomes complicated.

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

For the above photon mode type,
The thermal destruction method of (6) has an advantage that it can be handled in a bright room, and its usefulness has recently been reviewed due to the rapid progress of the output of the semiconductor laser serving 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 Laid-Open No. 6-199064, USP
No. 5339737, USP5353705, EP05
80393, JP-A-6-55523, EP0573.
No. 091, USP5378580 also describes a direct drawing type waterless planographic printing plate precursor using a laser beam as a light source.

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

Finally, by removing this portion by development, the silicone rubber layer on the surface is peeled off at the same time to form an ink inking 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 primary particle diameter of the carbon black used is not appropriate.

That is, the primary particle diameters of the carbon blacks used in the above patents are all 30 nm or more,
It cannot be said that the light of the semiconductor laser used (wavelength near 800 nm) is absorbed efficiently.

This is because the blackness as a printing plate, which is one measure of the absorption efficiency of laser light, does not reach the maximum with the above particle size.

That is, the blackness becomes maximum when the particle size is around 20 nm, and when it exceeds 30 nm, the blackness decreases. This is because the reflection of light on the surface increases.

Even if the particle diameter is smaller than 15 nm, the blackness is lowered.

This is because the smaller the particles, the more easily the carbon black itself becomes transparent and the lower the dispersibility of the particles.

Further, in particular, JP-A-6-55723, 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 improve the drawbacks of the prior art, the present invention has a primary particle size of carbon black of 15 nm.
It is an object of the present invention to provide a direct drawing type waterless planographic printing plate with improved sensitivity by setting the thickness to ˜29 nm.

[0027]

In order to achieve the above object, the present invention has the following constitution.

1. In 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, the heat sensitive layer has an average primary particle diameter of 15 nm to 2 nm.
A direct drawing type waterless planographic printing plate precursor characterized by containing 9 nm of carbon black.

2. 1. In the above 1, the heat-sensitive layer contains a thermally decomposable compound, which is a direct drawing type waterless planographic printing plate precursor.

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

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.

[0033]

Here, the direct drawing type means that an image is directly formed on a printing plate from a recording head 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 described.

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, 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.

Carbon black having various particle sizes is commercially available. Among them, it is important to use carbon black having an average primary particle size of 15 nm to 29 nm, preferably 17 nm. ~ 26 nm.

When the average particle size of the primary particles is smaller than 15 nm, the thermosensitive layer itself becomes transparent and cannot absorb the laser light efficiently, and when it is larger than 29 nm, the particles are high. Without being dispersed in the density, the blackness of the heat-sensitive layer does not increase, and similarly the laser light cannot be efficiently absorbed. This causes a problem that the sensitivity of the printing plate finally decreases.

The use of conductive carbon black also
It is effective in 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 the photothermal conversion substance added is preferably 2 to 70% by weight, more preferably 5 to 60% by weight, based on the total heat-sensitive layer composition. If the added amount is less than 2% by weight, the effect of improving the sensitivity is not observed, and if the added amount is more than 70% by weight, the printing durability of the printing plate tends to decrease.

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 this 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 herein is not for explosive use, 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 will be reduced to 80% by weight.
If it is more than the above range, the solvent resistance of the printing plate tends to decrease.

Examples of organic peroxides include ketone peroxide, peroxyketal, hydroperoxide,
Dialkyl peroxide, diacyl peroxide,
Examples include 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 by photocrosslinking, the thermal crosslinking type is preferable.

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 the amount is larger than the above range, 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 polyolefins such as chlorinated polyethylene, chlorinated polypropylene, and the like. Among them, cellulose derivatives such as cellulose acetate, polyvinyl chloride-vinyl acetate copolymer, etc. 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. A heat-sensitive layer is formed by uniformly applying such a composition solution on a substrate and heating at a required temperature for a required time.

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. Examples of such a dimensionally stable plate-like material include those conventionally used as a substrate for a printing plate, and they can be preferably 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 boards,
Aluminum plates are particularly preferable because they are extremely dimensionally stable and inexpensive. 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 such a composition solution on a substrate and heating 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.
It is 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]

[Chemical 1] (Here, n is an integer of 2 or more. R has 1 to 10 carbon atoms.
Is an alkyl, aryl, or cyanoalkyl group. It is preferable that 40% or less of the total R is vinyl, phenyl, vinyl halide, or phenyl halide, and 60% or more of R is a methyl group. Further, it has at least one hydroxyl group in the molecular chain in the form of a chain end or a side chain. ) In the case of the silicone rubber layer applied to the printing plate of the present invention, silicone rubber (R
TV, LTV type silicone rubber) is used. 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 amount of the cross-linking agent may be present.

[0089]

[Chemical 2]

[Chemical 3]

[Chemical 4] (Here, R is the same as R described above, and R1, R2
Is a monovalent lower alkyl group, and Ac is an acetyl group. ) Silicone rubber that performs such condensation-type crosslinking,
Metal carboxylates of tin, zinc, lead, calcium, manganese, etc., such as dibutyltin laurate, tin (II) octoate, naphthenates, etc., or catalysts such as chloroplatinic acid are 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.

Further, in the present invention, addition type silicone rubber may be used in addition to the above condensation type silicone rubber.

As the addition type silicone rubber, it is preferable to use, as shown below, a hydrogen polysiloxane having a Si—H bond and a vinyl polysiloxane having a CH═CH bond which are crosslinked and cured with a platinum catalyst. .

(1) 100 parts by weight of an organopolysiloxane having at least two alkenyl groups (preferably vinyl groups) directly bonded to a silicon atom in one molecule (2) at least 2 groups of the formula (V) in one molecule Organohydrogenpolysiloxane having 0.1 to 1000 parts by weight (3) Addition catalyst 0.00001 to 10 parts by weight The alkenyl group of the component (1) may be at the terminal or in the middle of the molecular chain, and other than the alkenyl group. As the organic group of
It is a substituted or unsubstituted alkyl group or aryl group.
The component (1) may have a small amount of hydroxyl groups. The component (2) reacts with the component (1) to form a silicone rubber layer,
It plays a role of imparting adhesiveness to the photosensitive layer. The hydrogen group of the component (2) may be at the terminal or in the middle of the molecular chain, and the organic group other than hydrogen is selected from the same as the component (1). The organic groups of the components (1) and (2) preferably have a methyl group content of 60% or more of the total number of the groups from the viewpoint of improving the ink repellency. Component (1) and component (2)
The molecular structure of may be linear, cyclic, or branched, and it is preferable that at least one of them has a molecular weight of more than 1000 from the viewpoint of rubber physical properties, and further, the molecular weight of component (2) may exceed 1,000. preferable. Examples of the component (1) include α, ω-divinylpolydimethylsiloxane and a (methylvinylsiloxane) (dimethylsiloxane) copolymer having methyl groups at both terminals, and the component (2) has a hydrogen group at both terminals. Polydimethylsiloxane, α, ω-
Examples thereof include dimethyl polymethyl hydrogen siloxane, (methyl hydrogen siloxane) (dimethyl siloxane) copolymer having methyl groups at both ends, and cyclic polymethyl hydrogen siloxane. The addition catalyst of the component (3) is arbitrarily selected from known ones, but a platinum-based compound is particularly desirable, and platinum simple substance, platinum chloride, chloroplatinic acid, olefin coordinated platinum and the like are exemplified. For the purpose of controlling the curing rate of these compositions, vinyl group-containing organopolysiloxane such as tetracyclo (methylvinyl) siloxane and carbon-carbon triple bond-containing alcohol-
It is also possible to add a crosslinking inhibitor such as alcohol, acetone, methyl ethyl ketone, methanol, ethanol and propylene glycol monomethyl ether. These compositions are characterized in that an addition reaction occurs at the time when the three components are mixed and curing begins, but the curing rate rapidly increases as the reaction temperature increases. Therefore, for the purpose of prolonging the pot life of the composition until rubberization and shortening the curing time on the photosensitive layer, the curing conditions of the composition are a temperature condition in which the characteristics of the substrate and the photosensitive layer are not changed, Further, it is preferable to keep the temperature at a high temperature until it is completely cured, from the viewpoint of stability of the adhesive force with the photosensitive layer.

The thickness of these silicone rubber layers is 0.5.
˜50 g / m ² is preferred, and more preferably 0.5˜.
It is 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 economical point of view.

For the purpose of protecting the heat-sensitive layer on the surface of the waterless planographic printing plate precursor constructed as described above, the surface of the heat-sensitive layer is provided with a thin protective film having a plane or a concavo-convex treatment. Or Japanese Patent Laid-Open No. 5-32358
It is also possible to form a polymer coating film that is soluble in the developing solvent described in JP-A No.

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

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.

Laser light is usually used for 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 name of ESSO-made isoparaffinic hydrocarbon), gasoline, kerosene, etc., aromatic hydrocarbons (toluene, xylene, etc.), halogenated hydrocarbons (tricrene, etc.), etc. A mixed solvent containing at least one of the following polar solvents 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.) Carvone Acid (2-ethylbutyric acid, Prong acid, caprylic acid, 2-ethylhexanoic acid, capric acid, oleic acid,
Lauric acid, etc.) Also, a known surfactant may be freely added to the above-mentioned developer composition. In addition, an 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, and 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

At the time of developing, the developing solution can be developed by impregnating a non-woven fabric, absorbent cotton, cloth, sponge or the like with the developing solution and wiping the plate surface.

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.

[0108]

The present invention will be described in more detail with reference to the following examples, but the present invention is not 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 (Kansai Paint Co., Ltd., epoxy phenolic resin) 15 parts by weight (b) Victoria Pure Blue BOH naphthalene sulfonic acid 0.1 part by weight (c) Dimethyl Formamide 85 parts by weight Next, a heat-sensitive layer composition having the following composition was applied on the 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) 30 parts by weight (b) carbon black (table 1) (c) Polyester resin (“Byron 300”, manufactured by Toyobo Co., Ltd.) 30 parts by weight (d) Modified epoxy resin (“Epokey” 803, manufactured by Mitsui Toatsu Chemicals, Inc.) 15 parts by weight (e) Diethylenetriamine 5 parts by weight (f) 600 parts by weight of methyl isobutyl ketone, and then 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.

Then, 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 1W, wavelength 809nm, manufactured by Sony Corporation, beam diameter 20μm, exposure time 1
Pulse exposure was performed for 0 μs. At this time, the laser output is L
The laser power on the printing plate was measured while arbitrarily changing it with a D pulse modulation driving device.

Subsequently, rubbing was performed with a cotton pad impregnated with a developing solution having the following composition 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 when the particle diameter of carbon black is out of the specified range, the sensitivity is lowered.

[0118]

[Table 1]

[0119]

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.

Continuation of the front page (56) Reference JP-A-63-293091 (JP, A) JP-A-60-83893 (JP, A) JP-A-50-158405 (JP, A) JP-A-50-102403 (JP , A) JP 7-81026 (JP, A) JP 6-199064 (JP, A) JP 6-55723 (JP, A) JP 5-24374 (JP, A) JP 4-263994 (JP, A) JP-A-4-238091 (JP, A) JP-A-3-159793 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41N 1/14 B41C 1/055 G03F 7/00

Claims (6)

(57) [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 has an average particle diameter of primary particles of 15 nm to 29 nm.
A direct drawing type waterless planographic printing plate precursor characterized by containing the above carbon black. 2. The heat-sensitive layer according to claim 1, wherein the heat-sensitive layer is composed of primary particles.
Carbon black with a uniform particle size of 17 nm to 26 nm
Direct drawing type waterless planographic printing plate precursor characterized by containing
Edition. 3. A direct drawing type waterless planographic printing plate precursor according to claim 1, wherein the heat sensitive layer contains a thermally decomposable compound. 4. The direct drawing type waterless lithographic printing plate precursor as claimed in claim 1, wherein the heat sensitive layer contains nitrocellulose. 5. A direct drawing type waterless planographic printing plate precursor according to claim 1, wherein the heat-sensitive layer is a thermal crosslinking type. 6. A directly imageable waterless planographic printing plate precursor according to any one of claims 1 to 5 selectively exposed, formed by developing,
Waterless planographic printing plate.