JP2020023125A - Lithographic printing plate original plate, method for manufacturing lithographic printing plate, and method for manufacturing printed matter - Google Patents

Abstract

To provide a lithographic printing plate original plate with high sensitivity on which less laser wavelength limitations are imposed in an image formation process.SOLUTION: A lithographic printing plate original plate includes in the following order: a substrate, a heat-sensitive layer containing carbon nano-tube, and an ink repulsive layer.SELECTED DRAWING: None

Description

  The present invention relates to a lithographic printing plate precursor and a method for producing a lithographic printing plate for use in lithographic printing, and a method for producing a printed matter using the same.

An image forming method of waterless lithographic printing, which is one of the lithographic printing methods, includes a method of irradiating ultraviolet rays through an original film and a computer-to-plate (hereinafter, CTP) for directly writing an image from an original without using the original film. ) Method. At present, the method of exposing with a thermal laser is the mainstream among the CTP methods. In this method, an image is formed by destroying a heat-sensitive layer by performing photothermal conversion by laser light irradiation to cause a thermal reaction. This type of lithographic printing plate has high sensitivity to laser light of a specific wavelength, but the sensitivity is greatly reduced when exposed using a laser of an unsuitable wavelength. Many. If a lithographic printing plate can have a high enough sensitivity to expose and develop not only laser light of a specific wavelength but also laser light of multiple wavelengths, it is possible to form images with various exposure machines. A small lithographic printing plate precursor can be obtained. For that purpose, a heat-sensitive layer having high sensitivity to a wide wavelength range is required.
To address this problem, Patent Document 1 discloses that a heat-sensitive layer of a direct-drawing waterless lithographic printing plate precursor contains two or more light-to-heat conversion substances having different absorption wavelengths, thereby providing two or more lasers having different oscillation wavelengths. (See Patent Document 1 (Claims, Paragraph 0044)).
Patent Document 1 discloses that carbon black is further contained in the heat-sensitive layer as a light-to-heat conversion material. Since carbon black has a wide absorption range from ultraviolet to infrared wavelengths, a heat-sensitive layer having absorption for a plurality of wavelengths of laser light has been obtained (see Patent Document 1 (paragraph 0041) in the specification).

International Publication No. WO 2016/143598

However, in the method described in Patent Document 1 in which the heat-sensitive layer contains two or more light-to-heat conversion substances having different absorption wavelengths, the heat-sensitive layer is appropriately used according to the absorption wavelength of the contained light-to-heat conversion substance. It is necessary to select the laser beam to be used. Therefore, the restriction on the laser beam to be used remains.
The method of including carbon black as a light-to-heat conversion substance in the heat-sensitive layer has a problem that the sensitivity of carbon black is low and a large laser output is required for exposure for producing a printing plate.

  For these reasons, a printing plate precursor having high sensitivity to laser light of a plurality of wavelengths has been demanded. Then, an object of the present invention is to provide a lithographic printing plate precursor with few restrictions on laser wavelength.

In order to solve the problem, the present invention has the following configuration.
(1) A lithographic printing plate precursor having a substrate, a heat-sensitive layer containing carbon nanotubes, and an ink repellent layer in this order.

Preferred embodiments of the lithographic printing plate precursor include the following.
(2) The lithographic printing plate precursor wherein the carbon nanotube is a single-walled carbon nanotube.
(3) The lithographic printing plate precursor as described above, wherein the heat-sensitive layer contains a polymer having active hydrogen.
(4) Any of the lithographic printing plate precursors having an adhesive layer between the heat-sensitive layer and the ink repellent layer.
(5) The lithographic printing plate precursor as described above, wherein the adhesive layer contains a polymer having active hydrogen.

The following is a method for obtaining a lithographic printing plate from the printing plate precursor.
(6) For the lithographic printing plate precursor according to any of the above,
(A) a step of exposing according to a desired image, and then (B) a step of applying friction to the exposed lithographic printing plate precursor to remove an ink repellent layer, or (C) exposing according to a desired image and repelling ink. A method for producing a lithographic printing plate having a step of removing a layer.

The following is a method for producing a printed matter.
(7) A method for producing a printed matter, comprising the steps of: adhering ink to the surface of a lithographic printing plate obtained by the lithographic printing plate production method; and transferring the ink to a printing medium directly or via a blanket. .
(8) For the lithographic printing plate precursor according to any of the above,
(A) a step of exposing according to a desired image, and then (B) a step of applying physical friction to the exposed master to remove an ink repellent layer, or (C) exposing according to a desired image to form an ink repellent layer. Removing,
To get a lithographic printing plate,
A method for producing a printed material by a step of attaching ink to the surface of the lithographic printing plate, and a step of transferring the ink to a printing medium directly or via a blanket.

  According to the present invention, it is possible to obtain a lithographic printing plate precursor that is less restricted by the laser wavelength in the exposure step and has high sensitivity.

  The lithographic printing plate precursor according to the invention will be described below.

  The lithographic printing plate precursor according to the invention has a heat-sensitive layer containing at least carbon nanotubes on a substrate and an ink repellent layer in this order.

The carbon nanotube has a structure in which a graphene sheet is rolled into a cylindrical shape.A carbon nanotube consisting of only one cylinder is a single-walled carbon nanotube, and a single-walled carbon nanotube having two different diameters is coaxially stacked. A double-walled carbon nanotube and a multilayered one are called a multi-walled carbon nanotube. Carbon nanotubes have their absorption extended to infrared wavelengths due to their developed π-conjugation. Therefore, the heat-sensitive layer containing carbon nanotubes has a very wide absorption in the ultraviolet to infrared wavelength range. Further, since the carbon nanotube has a large covering area on the substrate per unit mass, the carbon nanotube has high sensitivity to laser light of a plurality of wavelengths. This makes it possible to provide a lithographic printing plate precursor with less laser wavelength restrictions.
The lithographic printing plate precursor according to the invention can be used for both waterless printing and printing with water, and can be suitably used particularly for waterless printing.

  The lithographic printing plate precursor according to the invention has a substrate. At least a heat-sensitive layer and an ink repellent layer are provided on or above the substrate in this order. Although any of a heat-sensitive layer and an ink repellent layer may be provided near the substrate, it is preferable that the substrate, the heat-sensitive layer and the ink repellent layer are arranged in this order.

  Examples of the substrate that can be used in the present invention include paper, metal, glass, and film that have been conventionally used as a substrate for a printing plate and have little dimensional change in a printing process. Specifically, the following are exemplified.

  Paper laminated with paper and plastics (eg, polyethylene, polypropylene, polystyrene); metal plates such as aluminum (including aluminum alloys), zinc, and copper; glass plates such as soda lime and quartz; silicon wafers; cellulose acetate; Plastic films such as polyester such as terephthalate, polyethylene, polyamide, polyimide, polystyrene, polypropylene, polycarbonate and polyvinyl acetal; paper or plastic films on which the above metals are laminated or vapor-deposited. This plastic film may be transparent or opaque. From the viewpoint of plate inspection, an opaque film is preferable.

  Among these substrates, an aluminum plate is preferable because there is little dimensional change in the printing process. As a flexible substrate for light printing, a polyethylene terephthalate film is preferable.

  The thickness of the substrate is not particularly limited, and a thickness corresponding to a printing machine used for lithographic printing may be selected.

  The lithographic printing plate precursor according to the invention may have another layer between the substrate and the heat-sensitive layer. This layer is preferably a layer containing an organic substance (hereinafter referred to as “organic layer”). That is, when the substrate, the thermosensitive layer and the ink repellent layer are laminated in this order, an organic layer can be provided between the substrate and the thermosensitive layer. The characteristics of the organic layer used in the lithographic printing plate precursor according to the invention are to impart flexibility to the lithographic printing plate precursor and to have good adhesion to a substrate or a heat-sensitive layer. For example, an organic layer containing a metal chelate compound disclosed in JP-A-2004-334025 (specification paragraphs 0026 to 0035) is preferably used, but is not limited thereto.

  In the present invention, the organic layer may contain a flexibility-imparting agent such as a polyurethane resin, natural rubber, or synthetic rubber for the purpose of imparting flexibility and controlling scratch resistance. Among these softening agents, polyurethane resins are particularly preferably used in view of coating performance and coating liquid stability.

  The organic layer may contain an active hydrogen group-containing compound for the purpose of imparting adhesion to the substrate or the thermosensitive layer. Examples of the active hydrogen group-containing compound include a hydroxyl group-containing compound, an amino group-containing compound, a carboxyl group-containing compound, a thiol group-containing compound, and the like.A hydroxyl group-containing compound is preferable, and an epoxy resin is particularly preferable from the viewpoint of adhesion to a substrate. It is preferably used.

  In the present invention, the organic layer preferably contains a pigment. By containing an appropriate amount of the pigment, the light transmittance of the organic layer can be reduced to 15% or less for all the wavelengths of 400 to 650 nm, whereby the plate readability by machine reading can be imparted. As the pigment, it is preferable to use inorganic white pigments such as titanium oxide, zinc white, and lithopone, and inorganic yellow pigments such as graphite, cadmium yellow, yellow iron oxide, ocher, and titanium yellow. Among these pigments, titanium oxide is particularly preferred in terms of hiding power and coloring power.

  Next, the heat-sensitive layer that can be preferably used in the present invention will be described.

  As the heat-sensitive layer, when irradiated with laser light of various wavelengths used for drawing, at least the surface of the heat-sensitive layer is decomposed, the adhesive force with the ink repellent layer is reduced, or the solubility in the developer is reduced Is preferably increased. Such a heat-sensitive layer may be a layer containing (1) carbon nanotubes having a function of absorbing laser light and converting it into heat (photothermal conversion), and more preferably (1) carbon nanotubes and (2) active hydrogen. Is a layer containing a polymer having:

  In the present invention, a composition that is a raw material for producing the above-described heat-sensitive layer is referred to as a “heat-sensitive layer composition”.

  In the present invention, the heat-sensitive layer refers to a layer remaining after applying a solution in which the heat-sensitive layer composition is dispersed or dissolved and drying (removing volatile components). Drying may be performed at normal temperature or by heating.

In the present invention, the molecular presence form of (1) the carbon nanotube in the heat-sensitive layer is not particularly limited, and each may exist independently, in a bundle, or entangled, or a mixture thereof. Further, various layers or diameters may be included. Further, the heat-sensitive layer may contain impurities (for example, a catalyst or amorphous carbon) derived from the carbon nanotube production method.
(1) As the carbon nanotube, at least one of a single-walled carbon nanotube, a double-walled carbon nanotube, and a multi-walled carbon nanotube can be used. When a carbon nanotube having a small number of single-walled to double-walled carbon nanotubes is used, a lithographic printing plate precursor having a large covering area per unit mass, a large absorbance of a heat-sensitive layer, and a higher sensitivity can be obtained. Of all the carbon nanotubes present in the heat-sensitive layer, the number of single-walled carbon nanotubes is preferably 50% by mass or more, more preferably 50% by mass or more. More preferably, the content of the single-walled carbon nanotube is 100% by mass.

The number of layers of carbon nanotubes can be measured, for example, by preparing a sample as follows.
After dissolving the heat-sensitive layer with a good solvent, the obtained solution is filtered using filter paper (PTFE, pore size: 1.0 μm) (manufactured by ADVANTEC). The carbon nanotubes on the filter paper are sufficiently washed, and the heat-sensitive layer composition other than the carbon nanotubes is removed from the filter paper. After that, a surfactant (for example, sodium dodecyl sulfate) is added to the carbon nanotubes on the filter paper and redispersed in water. Several μL of the redispersed liquid is dropped on a Cu grid and dried under reduced pressure. Wash the dried product with water. The carbon nanotubes on the Cu grid are measured with a transmission electron microscope. The concentration of the carbon nanotubes in the liquid dropped onto the Cu grid may be any concentration at which the carbon nanotubes can be observed one by one, and is, for example, 0.001% by mass.

The number of layers of the carbon nanotube is measured, for example, as follows. Observation was performed at a magnification of 400,000 using a transmission electron microscope, and the number of layers was determined for 100 carbon nanotubes arbitrarily extracted from a visual field in which 10% or more of the visual field area was a carbon nanotube in a visual field of 75 nm square. Measure. When 100 lines cannot be measured in one visual field, measurement is performed from a plurality of visual fields until 100 lines are obtained. At this time, one carbon nanotube is counted as one if a part of the carbon nanotube is visible in the visual field, and both ends are not necessarily required to be visible. Further, even if two lines are recognized in the visual field, they may be connected outside the visual field and become one, but in such a case, two lines are counted.
The diameter of the carbon nanotubes is not particularly limited, but the average value of the outer diameter of the carbon nanotubes in the above preferred range of the number of layers is 1 nm to 10 nm, and particularly those having a range of 1 to 3 nm are preferably used. The average value of the outer diameter was observed at a magnification of 250,000 using the above-mentioned transmission electron microscope, and 100% of 100% of the carbon nanotubes were arbitrarily extracted from a visual field where 10% or more of the visual field area was a carbon nanotube in a visual field of 75 nm square. This is an arithmetic average value when the sample is observed in the same manner as in the measurement of the number of layers of this carbon nanotube and the outer diameter of the carbon nanotube is measured.

  Further, (1) the carbon nanotubes used in the present invention are preferably used in a state of being uniformly dispersed in the thermosensitive layer composition. This is because the carbon nanotubes are uniformly present in the heat-sensitive layer during the formation of the heat-sensitive layer, and the coating area per unit mass is increased, so that a lithographic printing plate precursor having a large absorbance of the heat-sensitive layer and a higher sensitivity can be obtained. is there.

In a solid state, carbon nanotubes form a bundle structure by van der Waals force or the like, and are extremely difficult to disperse in water or a general-purpose solvent. Therefore, in order to uniformly disperse the carbon nanotubes, chemical modification and / or physical modification are usually performed.
Chemical modification is a modification method in which a functional group that enables solvation is covalently introduced into the surface of a carbon nanotube. As a general method of chemical modification, treatment with nitric acid, a mixed acid, or hydrogen peroxide can be mentioned. When the carbon nanotubes are treated with hydrogen peroxide, the carbon nanotubes are mixed, for example, in a commercially available 34.5% hydrogen peroxide solution to a concentration of 0.01 to 10% by mass, and the mixture is heated to a temperature of 0 to 100 ° C. For 0.5 to 48 hours. When the carbon nanotubes are treated with a mixed acid, the carbon nanotubes are mixed, for example, in a mixed solution of concentrated sulfuric acid / concentrated nitric acid (3/1 mass ratio) so as to have a concentration of 0.01 to 10% by mass. The reaction can be performed at a temperature of 100 ° C. for 0.5 to 48 hours. As the mixing ratio of the mixed acid, the mass ratio of concentrated sulfuric acid / concentrated nitric acid can be 1/10 to 10/1 according to the amount of single-walled carbon nanotubes in the generated carbon nanotubes. When the carbon nanotubes are treated with nitric acid, the carbon nanotube-containing composition is mixed with, for example, a commercially available aqueous solution of 40 to 80% by mass of nitric acid so as to have a concentration of 0.01 to 10% by mass. At a temperature of 0.5 to 48 hours.

  By performing such a treatment, the surface of the carbon nanotube becomes a functional group such as a carboxyl group, whereby the affinity with the dispersion medium is improved and the dispersibility is improved.

  (B) The physical modification is a method in which a dispersant is non-covalently introduced into the carbon nanotube surface. Dispersants include low molecular dispersants and high molecular dispersants. Examples of the low molecular dispersant include surfactants such as sodium dodecyl sulfate and sodium dodecylbenzene sulfate, and polycyclic aromatic compounds such as pyrene derivatives and porphyrin derivatives. Examples of the polymer dispersant include block copolymers such as polystyrene-polyacrylic acid, polystyrene-polymethacrylic acid, and polystyrene-polyethylene oxide, and conjugated polymers such as polyparaphenylenevinylene derivatives. As a general method of physical modification, for example, the carbon nanotubes are mixed in an aqueous solution of 0.01 to 10% by mass of sodium dodecyl sulfate so as to be 0.01 to 1% by mass, and are mixed at room temperature for 0.5 to 10 hours. A dispersion solution can be obtained by ultrasonic irradiation.

  The (1) carbon nanotube of the present invention is preferably physically modified and dispersed in the thermosensitive layer composition. Physical modification is preferable because a carbon nanotube having fewer defects on the surface is generally obtained as compared with chemical modification, so that a heat-sensitive layer that provides a lithographic printing plate precursor with higher absorbance and consequently higher sensitivity is obtained.

  (1) The length of the carbon nanotube is not particularly limited, but if it is too short, the film-forming ability tends to decrease, so it is preferably at least 0.5 μm, more preferably at least 1 μm. If the length is too long, the dispersibility tends to decrease, so that it is preferably 10 μm or less, more preferably 5 μm or less.

The length of the carbon nanotube can be measured, for example, by preparing a sample as follows.
After dissolving the heat-sensitive layer with a good solvent, the obtained solution is filtered using filter paper (PTFE, pore size: 1.0 μm) (manufactured by ADVANTEC) to sufficiently remove carbon nanotubes on the filter paper. Washing is performed to remove the heat-sensitive layer composition other than carbon nanotubes from the filter paper. Thereafter, the carbon nanotubes on the filter paper are redispersed in water with a surfactant (for example, sodium dodecyl sulfate). Several μL of a carbon nanotube liquid is dropped on a mica substrate, air-dried, and then washed with water. The length of the carbon nanotube on the mica substrate can be examined with an atomic force microscope. The concentration of the liquid of the carbon nanotubes dropped on the mica substrate is preferably a concentration at which the carbon nanotubes can be observed one by one, and may be appropriately diluted, but is, for example, 0.003% by mass.

  Regarding the length of carbon nanotubes, a sample was prepared by the above method, observed with an atomic force microscope, and a photograph was taken where 10 or more carbon nanotubes were included in a 30 μm square visual field. Measure the length. The length of 100 carbon nanotubes arbitrarily extracted from the visual field is measured along the length direction. When 100 lines cannot be measured in one visual field, measurement is performed from a plurality of visual fields until 100 lines are obtained. By measuring the length of 100 carbon nanotubes in total, the length and the number of carbon nanotubes included in 100 carbon nanotubes can be confirmed. In the present invention, when the number of carbon nanotubes having a length in the range of 0.5 μm or less is equal to or less than 30 out of 100, sufficient film-forming ability is obtained, and the carbon nanotubes in the range of 1 μm or less are preferable. More preferably, the number is 30 or less out of 100. Further, in the present invention, it is preferable that the number of carbon nanotubes having a length of 10 μm or more is 30 or less out of 100, because dispersibility can be improved. If the length of the carbon nanotube is long and the entire length is not visible in the field of view, measure the length of the carbon nanotube in the field of view. The number of carbon nanotubes in the range of 0.5 to 10 μm is counted assuming that the length is more than 10 μm.

  Further, the carbon nanotube (1) used in the present invention is not particularly limited, but is preferably a carbon nanotube having a high degree of crystallinity. Carbon nanotubes with a high degree of crystallinity have more π-conjugation than carbon nanotubes with a low degree of crystallinity, and therefore have a large extinction coefficient, particularly in the near-infrared region, and can be more sensitive to laser light.

The crystallinity of carbon nanotubes can be evaluated by Raman spectroscopy. Although there are various laser wavelengths used in the Raman spectroscopy, 532 nm is used here. The peak seen at about 1590 cm ⁻¹ in the Raman spectrum is called a G band derived from the in-plane stretching vibration of the six-membered ring structure in the graphite structure, and the peak seen at about 1300 cm ⁻¹ is a defect of amorphous carbon or graphite. This is called the D band derived from Therefore, a carbon nanotube having a higher intensity ratio (G / D ratio) between the G band and the D band has a higher crystallinity.

  The crystallinity of the carbon nanotubes in the heat-sensitive layer is measured by irradiating a laser (wavelength 532 nm) to the lithographic printing plate precursor from the ink repellent layer side using a resonance Raman spectrometer to evaluate the G / D ratio. You can tell by doing. The higher the G / D ratio, the smaller the number of defects on the surface of the carbon nanotube, and thus the higher the absorbance of the heat-sensitive layer. It is preferably 30 or more, more preferably 40 or more, and even more preferably 50 or more. Since the G / D ratio may vary depending on the measurement location in the lithographic printing plate precursor, Raman spectroscopy is performed on at least three other locations, and the arithmetic mean thereof is taken.

  Further, (1) the content of the carbon nanotubes in the heat-sensitive layer is preferably 10% by mass or more, more preferably 20% by mass or more, from the viewpoint of obtaining sensitivity to laser light. In addition, it is preferably 80% by mass or less, more preferably 70% by mass or less, from the viewpoint that the adhesive force with the upper ink repellent layer can be kept high.

In the present invention, (2) a polymer having active hydrogen which is preferably used for the heat-sensitive layer includes a polymer having a structural unit having active hydrogen. The structural unit having an active hydrogen for _{example, -OH, -SH, -NH 2,} -NH -, - CO-NH 2, -CO-NH -, - OC (= O) -NH -, - NH-CO -NH -, - CO-OH, -CS-OH, -CO-SH, -CS-SH, -SO 3 H, -PO 3 H 2, -SO 2 -NH 2, -SO 2 -NH -, - _CO-CH 2 -CO- and the like.

The following are examples of the polymer having the active hydrogen (2).
Homopolymer or copolymer of a monomer having a carboxyl group such as (meth) acrylic acid; and (meth) acrylic acid ester having a hydroxyl group such as hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate Homopolymer or copolymer; N-alkyl (meth) acrylamide, homopolymer or copolymer of (meth) acrylamide; homopolymer of reaction product of amines with glycidyl (meth) acrylate or allyl glycidyl, or Copolymer; homopolymer or copolymer of ethylenically unsaturated monomer having active hydrogen such as homopolymer or copolymer of p-hydroxystyrene and vinyl alcohol; Other ethylenically unsaturated monomers having hydrogen may be used, Sex hydrogen may be ethylenically unsaturated monomers containing no.

Examples of the polymer having a structural unit having active hydrogen include a polymer having a structural unit having active hydrogen in the main chain. Examples of such polymers include polyurethanes, polyureas, polyamides, epoxy resins, polyalkylene imines, melamine resins, novolak resins, resole resins, cellulose derivatives, and the like. Two or more of these may be contained.
Among them, homopolymers or copolymers of ethylenically unsaturated monomers having active hydrogen, polyurethanes, epoxy, and the like have a large interaction with carbon nanotubes and can improve the dispersion state of carbon nanotubes in the thermosensitive layer. Preferred are resins, polyalkylene imines and cellulose derivatives. Further, among these, cellulose derivatives are more preferable because of excellent adhesion to the ink repellent layer. Examples of the cellulose derivatives include ethyl cellulose and nitrocellulose.

  (2) The content of the polymer having active hydrogen is preferably 10% by mass or more, more preferably 30% by mass or more in the heat-sensitive layer, from the viewpoint that the adhesive force with the ink repellent layer can be kept high. Further, from the viewpoint of maintaining the sensitivity of the heat-sensitive layer in a high state, the amount is preferably 80% by mass or less, more preferably 70% by mass or less.

In the lithographic printing plate precursor according to the invention, the heat-sensitive layer may contain various additives as necessary. For example, a silicone-based surfactant or a fluorine-based surfactant may be contained in order to improve the coating property. Further, a silane coupling agent, a titanium coupling agent, or the like may be contained in order to enhance the adhesiveness with the ink repellent layer. The content of these additives varies depending on the purpose of use, but is generally preferably 0.1 to 30% by mass based on the total solid content of the thermosensitive layer.
Furthermore, in the lithographic printing plate precursor according to the invention, the average thickness of the heat-sensitive layer is preferably 0.5 μm or more, more preferably 0.7 μm or more, from the viewpoint that the sensitivity of the lithographic printing plate can be maintained in a high state. 0 μm or more is more preferable. In order to maintain the strength of the heat-sensitive layer in a high state, the thickness is preferably 10.0 μm or less, more preferably 5.0 μm or less, and still more preferably 3.0 μm or less. Here, the average thickness of the heat-sensitive layer can be determined by cross-sectional SEM observation. More specifically, a section of a lithographic printing plate precursor is embedded in a resin, and a cross section is prepared by an ion milling method (BIB method), and then a field emission scanning electron microscope (FE-SEM) (for example, “SU8020 (Hitachi The thickness can be measured by performing a cross-sectional SEM observation using “Technologies)”). The average film thickness can be determined by measuring the film thickness at 10 points randomly selected from the heat-sensitive layer in the SEM observation range and calculating the number average value.
The lithographic printing plate precursor according to the invention may have an adhesive layer between the heat-sensitive layer and the ink repellent layer. The properties of the adhesive layer used in the lithographic printing plate precursor according to the present invention have good adhesiveness to both the heat-sensitive layer and the ink repellent layer, and enable the ink repellent layer in the lithographic printing plate precursor to adhere firmly. . Another object of the present invention is to provide scratch resistance and printing durability to the lithographic printing plate precursor. Such an adhesive layer may be a layer containing a polymer having active hydrogen in that it has an adhesive property between the heat-sensitive layer and the ink repellent layer.

In the present invention, a composition that is a raw material for producing the above-described adhesive layer is referred to as an “adhesive layer composition”.
In the present invention, the adhesive layer refers to a layer remaining after applying a solution in which the adhesive layer composition is dispersed and drying (removing volatile components). Drying may be performed at room temperature or by heating.
The polymer having active hydrogen in the adhesive layer preferably contains melamine resins, novolak resins, and resol resins, and more preferably contains melamine resins. Two or more of these may be contained.
Further, in the lithographic printing plate precursor according to the invention, the average thickness of the adhesive layer is preferably 0.05 μm or more, more preferably 0.1 μm or more, in that the adhesion between the heat-sensitive layer and the ink repellent layer can be sufficiently improved. It is more preferably at least 0.3 μm. In order to maintain the sensitivity of the lithographic printing plate precursor in a high state, it is preferably 1.5 μm or less, more preferably 1.0 μm or less, and further preferably 0.7 μm or less. Here, the average thickness of the adhesive layer can be determined by observation with a transmission electron microscope. More specifically, the film thickness can be measured by observation with a transmission electron microscope under the conditions of an acceleration voltage of 100 kV and a direct magnification of 40 k. The average film thickness can be determined by measuring the film thickness at 10 locations randomly selected from the adhesive layer and calculating the number average value.

  As the ink repellent layer in the lithographic printing plate precursor according to the invention, a silicone rubber layer which is a crosslinked product of polyorganosiloxane can be preferably used. As the silicone rubber layer, a layer obtained by applying an addition-reaction-type silicone rubber layer composition or a condensation-reaction-type silicone rubber layer composition, a solution of these compositions is applied, and dried (heated if necessary). The resulting layers are mentioned.

  The addition reaction type silicone rubber layer composition preferably contains at least a vinyl group-containing organopolysiloxane, a SiH group-containing compound (addition reaction type crosslinking agent) and a curing catalyst. Further, a reaction inhibitor may be contained.

The vinyl group-containing organopolysiloxane has a structure represented by the following general formula (I) and has a vinyl group at a main chain terminal or in the main chain. Among them, those having a vinyl group at the terminal of the main chain are preferred. Two or more of these may be contained.
— (SiR ¹ R ² —O—) _n — (I)
In the formula, n represents an integer of 2 or more. R ¹ and R ² may be the same or different, and in the repeating structure, R ¹ may be the same or different, and R ² may be the same or different. R ¹ and R ² each represent a saturated or unsaturated hydrocarbon group having 1 to 50 carbon atoms. The hydrocarbon group may be linear, branched or cyclic, and may contain an aromatic ring.

  Examples of the SiH group-containing compound include a polydiorganosiloxane in which a part of an organic group is substituted by hydrogen. For example, an organohydrogenpolysiloxane and an organic polymer having a diorganohydrogensilyl group can be mentioned, and an organohydrogenpolysiloxane is preferable. Two or more of these may be contained.

  The organohydrogenpolysiloxane can have a linear, cyclic, branched, or network molecular structure. For example, polymethyl hydrogen siloxane having both molecular chains terminated with trimethylsiloxy groups, a dimethylsiloxane / methyl hydrogen siloxane copolymer having both molecular chains terminated with trimethylsiloxy groups, and dimethylhydrogen having both molecular chains terminated with dimethylhydrogen Examples thereof include dimethylpolysiloxane blocked with a gensiloxy group.

  From the viewpoint of the curability of the silicone rubber layer, the content of the SiH group-containing compound is 0.5 mass of the solid content of the silicone rubber layer composition (the portion excluding the solvent in the composition; the same applies hereinafter). % Or more, and more preferably 1% by mass or more. Further, it is preferably at most 20% by mass, more preferably at most 15% by mass.

  A curing catalyst is used in the addition reaction type silicone rubber layer composition. Platinum compounds are preferable, and specific examples thereof include simple platinum, platinum chloride, chloroplatinic acid, olefin-coordinated platinum, an alcohol-modified complex of platinum, and a methylvinylpolysiloxane complex of platinum. Two or more of these may be contained. The silicone rubber layer composition of the addition reaction type can contain a reaction inhibitor. Examples thereof include a nitrogen-containing compound, a phosphorus compound, and an unsaturated alcohol, and an alcohol having a carbon-carbon triple bond is particularly preferably used. Two or more of these may be contained.

  In addition, in addition to these components, the addition reaction type silicone rubber layer composition includes a hydroxyl group-containing polyorganosiloxane, a hydrolyzable functional group-containing silane or a siloxane containing this functional group, and silica for the purpose of improving rubber strength. And a silane coupling agent for the purpose of improving the adhesiveness. As the silane coupling agent, alkoxysilanes, acetoxysilanes, ketoximinosilanes, and the like are preferable.Since those in which a vinyl group or an allyl group is directly bonded to a silicon atom are incorporated into the chemical structure of the silicone rubber, the adhesiveness is low. Up is preferred.

  The condensation reaction type silicone rubber layer composition preferably uses at least a hydroxyl group-containing polyorganosiloxane, a crosslinking agent and a curing catalyst as raw materials.

The hydroxyl group-containing polyorganosiloxane has a structure represented by the general formula (II).
— (SiR ³ R ⁴ —O—) _m — (II)
In the formula, m represents an integer of 2 or more. R ³ and R 4 may be the same or different, and in the repeating structure, R ³ may be the same or different, and R ⁴ may be the same or different. R ³ and R ⁴ each represent a saturated or unsaturated hydrocarbon group having 1 to 50 carbon atoms. The hydrocarbon group may be linear, branched or cyclic, and may contain an aromatic ring. And it has a hydroxyl group at the terminal of the main chain, or a part of R ³ and / or R ^{4 in} the main chain is substituted with a hydroxyl group. Among them, those having a hydroxyl group at the terminal of the main chain are preferred. Two or more of these may be contained.

Examples of the crosslinking agent include silicon compounds represented by the following general formula (III), such as deacetic acid type, deoxime type, dealcohol type, deacetone type, deamide type, dehydroxylamine type and the like.
(R ⁵ ) _4-m Six _m (III)
In the formula, m represents an integer of 2 to 4, R ⁵ may be the same or different, and represents a substituted or unsubstituted alkyl group having 1 or more carbon atoms, an alkenyl group, an aryl group, or a combination thereof. Show. X may be the same or different and represents a hydrolyzable group. Examples of the hydrolyzable group include an acyloxy group such as an acetoxy group, a ketoxime group such as a methylethylketoxime group, and an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. In the above formula, the number of hydrolyzable groups, m, is preferably 3 or 4.

  From the viewpoint of the stability of the silicone rubber layer composition and its solution, the addition amount of the crosslinking agent in the condensation reaction type silicone rubber layer composition is preferably 0.5% by mass or more in the solid content of the silicone rubber layer composition. It is more preferably at least 1% by mass. In addition, from the viewpoint of the strength of the silicone rubber layer and the scratch resistance of the lithographic printing plate, the content is preferably 20% by mass or less, more preferably 15% by mass or less, in the solid content of the silicone rubber layer composition.

  Examples of the curing catalyst contained in the condensation reaction type silicone rubber layer composition include dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate, zinc octylate, and iron octylate. Two or more of these may be contained.

  The ink repellent layer of the lithographic printing plate precursor according to the invention may contain an ink repellent liquid for the purpose of improving image reproducibility or improving ink repellency. The ink repellent liquid preferably has a boiling point at 150 ° C. or more at 1 atm. Since the crosslinked structure of the ink repellent layer is weakened during the preparation of the master, the removal of the ink repellent layer during development is facilitated and the image reproducibility is improved. Further, when the plate surface is pressurized during printing, the ink-repellent liquid is exposed on the surface of the ink-repellent layer, and the ink repellency is improved by helping the ink to be removed. When the boiling point is 150 ° C. or higher, the lithographic printing plate precursor is less likely to volatilize during production, and the effect of the ink repellency obtained by adding the ink repellent liquid is less likely to be lost.

  Inclusion of the liquid in the ink repellent layer improves image reproducibility and ink repellency, but the content in the silicone rubber layer is preferably from 10% by mass to 35% by mass. When the content is 10% by mass or more, the resilience of the ink is remarkably improved, and when the content is 35% by mass or less, the strength of the silicone rubber layer can be sufficiently ensured, so that the printing durability can be maintained.

  The ink-repellent liquid is preferably a silicone compound, more preferably a silicone oil. The silicone oil referred to in the present invention refers to a polysiloxane component which is not involved in the crosslinking of the ink repellent layer and has an apparent fluidity. Accordingly, dimethyl silicone oils such as terminal dimethylpolydimethylsiloxane, cyclic polydimethylsiloxane, dimethyl-polydimethyl-polymethylphenylsiloxane copolymer, and alkyl-modified silicone oil, fluorine-modified silicone oil, polyether-modified silicone oil, etc. Modified silicone oils in which various organic groups are introduced into some of the methyl groups in the molecule are mentioned.

  The molecular weight of these silicone oils can be measured by gel permeation chromatography (GPC) using polystyrene as a standard, and preferably has a weight average molecular weight Mw of 1,000 to 100,000.

  In the lithographic printing plate precursor according to the invention, the average thickness of the silicone rubber layer is preferably 0.5 to 20 μm. When the average thickness of the silicone rubber layer is 0.5 μm or more, the ink repellency, scratch resistance, and printing durability of the printing plate become sufficient, and when the average thickness is 20 μm or less, it is not disadvantageous from an economic viewpoint, and image development is performed. Of ink and ink mileage are unlikely to occur. Here, the average thickness of the silicone rubber layer can be determined by TEM observation. More specifically, the thickness can be measured by preparing a sample from the lithographic printing plate precursor by the ultra-thin section method and performing TEM observation under the conditions of an acceleration voltage of 100 kV and a direct magnification of 2000 times. The average film thickness can be determined by measuring the film thickness at ten locations randomly selected from the silicone rubber layer and calculating the number average value.

  The lithographic printing plate precursor according to the invention may have a protective film and / or interleaf paper on the surface of the ink repellent layer for the purpose of protecting the ink repellent layer.

  As the protective film, a film having a thickness of 100 μm or less that transmits light having an exposure wavelength well is preferable. Representative examples of the film material include polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, cellophane, and the like. For the purpose of preventing the original from being exposed to light, various light absorbers, photochromic substances, and photobleachable substances (for example, Japanese Patent No. 2938886 (column 4, line 30 to column 5, line 18)) are disclosed. Described)) on a protective film.

The slip sheet is preferably one weighing 30 to 120 g / ^{m 2,} and more preferably from 30~90g / ^{m 2.} If the weighing is 30 g / m ² or more, the mechanical strength is sufficient, and if it is 120 g / m ² or less, not only is it economically advantageous, but also the laminate of the lithographic printing plate precursor and paper becomes thin. , Workability becomes advantageous. Examples of preferably used interleaf paper include, for example, information recording base paper 40 g / m ² (manufactured by Nagoya Pulp Co., Ltd.), metal interleaf paper 30 g / m ² (manufactured by Nagoya Pulp Co., Ltd.), unbleached kraft paper 50 g / m 2 ² (manufactured by Chuetsu Pulp Industry Co., Ltd.), NIP paper 52 g / m ² (manufactured by Chuetsu Pulp Industry Co., Ltd.), pure white roll paper 45 g / m ² (manufactured by Oji Paper Co., Ltd.), Krupak 73 g / m ² (Oji Papermaking Co., Ltd.) and the like, but are not limited thereto.

  Next, a method for producing a lithographic printing plate from the lithographic printing plate precursor according to the invention will be described. The following method is exemplified as a method of manufacturing a lithographic printing plate.

  First, (A) a step of exposing according to a desired image, and then (B) friction is applied to the exposed lithographic printing plate precursor to remove an ink repellent layer in an exposed portion. The step of exposing according to a desired image is called an exposing step. Applying friction to the exposed lithographic printing plate precursor is called a developing step.

  Second, the lithographic printing plate precursor is exposed according to a desired image (C), and the ink repellent layer is removed by a step of removing the ink repellent layer.

  As a result, the ink repellent layer on the exposed portions of the lithographic printing plate precursor is removed to form a lithographic printing plate.

  First, exposure according to a desired image will be described. In this step, the lithographic printing plate precursor according to the invention is exposed according to an image. When the lithographic printing plate precursor has a protective film, the lithographic printing plate precursor may be exposed from above the protective film, or may be exposed after exposing the protective film. As a light source used in the exposure step, a light source having an emission wavelength region in a range of 300 nm to 1500 nm may be mentioned. Among these, a semiconductor laser or a YAG laser having an emission wavelength region near the near infrared region is preferably used because it is widely used as an absorption wavelength of the heat-sensitive layer. Specifically, a laser beam having one or more wavelengths selected from 780 nm, 808 nm, 830 nm, and 1064 nm is preferably used for exposure from the viewpoint of heat conversion efficiency.

  Next, the developing step will be described. In the developing step, the lithographic printing plate precursor after exposure is given physical friction to remove the ink repellent layer in the exposed area. Examples of the method of imparting physical friction include (i) a method of wiping the plate surface with a non-woven fabric, absorbent cotton, cloth, sponge, or the like impregnated with a developer; A method of rubbing with a rotating brush, and (iii) a method of injecting high-pressure water, hot water, or steam onto the plate surface.

  Prior to development, a pretreatment may be performed in which the lithographic printing plate precursor is immersed in a pretreatment solution for a certain period of time. Examples of the pretreatment liquid include water, a solvent obtained by adding a polar solvent such as alcohol, ketone, ester and carboxylic acid to water, and a solvent containing at least one kind of aliphatic hydrocarbons and aromatic hydrocarbons. To which a polar solvent is added, or a polar solvent is used. As the pretreatment liquid, for example, a pretreatment liquid containing polyethylene ether diol and a diamine compound having two or more primary amino groups as described in Japanese Patent No. 4839987 can be used. Specific examples of the pretreatment liquid include PP-1, PP-3, PP-F, PP-FII, PTS-1, CP-1, CP-Y, NP-1, and DP-1 (all of which are manufactured by Toray Industries, Inc. ) And trade name).

  As the developer, for example, water, an aqueous solution in which 50% by mass or more of the entire solution is water, alcohol, or a paraffinic hydrocarbon can be used. Also, a mixture of propylene glycol, dipropylene glycol, triethylene glycol, polypropylene glycol, a propylene glycol derivative such as an alkylene oxide adduct to polypropylene glycol, and water can be used. Specific examples of the developer include HP-7N and WH-3 (both manufactured by Toray Industries, Inc.). A known surfactant can be added to the composition of the developer. As the surfactant, those having a pH of 5 to 8 when converted into an aqueous solution are preferable from the viewpoints of safety, cost at the time of disposal, and the like. The content of the surfactant is preferably 10% by mass or less of the developer. Such a developing solution has high safety and is preferable in terms of economical efficiency such as disposal cost.

  In addition, in order to improve the visibility of the image area and the measurement accuracy of halftone dots, a dye such as crystal violet, Victoria Pure Blue, Astrazone Red, etc. is added to the pre-treatment solution or developer to develop the image area simultaneously with development. Dyeing of the ink receiving layer can also be performed. Further, after the development, it can be dyed with a solution to which the above dye is added.

  Part or all of the above-mentioned developing step can be automatically performed by an automatic developing machine. The following devices can be used as automatic developing machines. Apparatus having only a developing section, an apparatus having a pre-processing section and a developing section in this order, an apparatus having a pre-processing section, a developing section, and a post-processing section in this order, a pre-processing section, a developing section, a post-processing section, and washing with water. A device whose units are provided in this order. Specific examples of such an automatic developing machine include TWL-650 series, TWL-860 series, TWL-1160 series (both manufactured by Toray Industries, Inc.), and JP-A-5-6000. An automatic developing machine in which a pedestal is dented into a curved surface in order to suppress the generation of scratches on the back surface of the plate is exemplified. These may be used in combination.

  In order to store the developed lithographic printing plates in a stacked state, it is preferable to insert a slip sheet between the plates for the purpose of plate surface protection.

  Next, an example of a method for producing a printed matter from the planographic printing plate of the invention will be described. The lithographic printing plate of the present invention can be used for both printing with water and printing without water. From the viewpoint of the quality of printed matter, printing without water using dampening water is more preferable. The layer derived from the heat-sensitive layer from which the ink repellent layer has been removed becomes the ink receiving layer, which becomes the image area. The ink repellent layer becomes a non-image area. It can be said that the ink receiving layer and the ink repelling layer have only a step on the order of microns and are substantially on the same plane. Then, the ink is applied only to the image portion by utilizing the difference in the ink adhesion, and then the ink is transferred to the printing medium and printed. The printing medium refers to all printing media such as thin paper, cardboard, film, and label, and is not particularly limited. The transfer of the ink may be performed directly from the lithographic printing plate to the printing medium, or may be performed via a blanket.

  Hereinafter, the present invention will be described based on examples, but the present invention is not limited to these examples.

(1) Evaluation of plate sensitivity to a plurality of laser wavelengths The lithographic printing plate precursor of the example was irradiated with a semiconductor laser “OPC-A001-mmm-FC” (780 nm wavelength, manufactured by OPTO POWER CORPORATION) to have a beam diameter of 20 μm. To perform pulse exposure. At this time, the output of the laser was changed to 300 mW, 275 mW, 250 mW, 225 mW, 200 mW, 175 mW, and 150 mW, and each was exposed for 2 minutes.

  Further, a laser used is a semiconductor laser (wavelength 780 nm), a semiconductor laser “QD-Q1910-IL” (wavelength 980 nm, manufactured by Nippon Laser Co., Ltd.), and a semiconductor-excited Nd: YAG laser “RBAT POWERPULSE” (wavelength 1064 nm, ( And the same exposure operation as above was performed at another position of the lithographic printing plate precursor.

  The exposed plate was passed through an automatic developing machine "TWL-1160F" (manufactured by Toray Industries, Inc.) at a speed of 60 cm / min to produce a lithographic printing plate. At this time, a rotary brush rub development was performed using tap water as a developer without using a pretreatment liquid.

The plate surface of the obtained lithographic printing plate was observed with an optical microscope “ECLIPSE L200N” (manufactured by Nikon Corporation), and if the silicone layer in the exposed portion had been removed, it was judged that it was reproduced. The plate sensitivity was checked. The plate sensitivity referred to here is the wattage of the laser output with the lowest output among the laser outputs from which reproduction was obtained. The smaller the number, the better the sensitivity of the plate. If it is 250 mW or less, it can be used without any practical problem. In the case where the reproduction was not performed at all the irradiated laser outputs, the plate sensitivity at that wavelength is represented as> 300 mW.
(2) Evaluation of Adhesive Strength of Ink Repellent Layer Irradiation energy: 250 mJ / cm ^{2 on} the lithographic printing plate precursor of Example using an exposure machine for CTP “PlateRite 8800E” (manufactured by Dainippon Screen Mfg. Co., Ltd.). (Wavelength: 808 nm, drum rotation speed: 120 rpm) Exposure was performed. The center of a lithographic printing plate precursor having a length of 400 mm and a width of 300 mm was exposed at 175 lpi at 2400 dpi. The pre-exposed original plate was passed through an automatic developing machine “TWL-1160F” (manufactured by Toray Industries, Inc.) at a speed of 60 cm / min to produce a lithographic printing plate. At this time, a rotary brush rub development was performed using tap water as a developer without using a pretreatment liquid.

  The obtained lithographic printing plate was visually observed, and the area where the silicone rubber was peeled off from the unexposed portion at 80% halftone dot was 0%, more than 0% and less than 2.5%, and 2.5% or more 5%. %, 5% or more and less than 10%, and 10% or more and less than 20% were evaluated as 5, 4, 3, 2, or 1 point, respectively. The higher the score, the better the adhesive force of the ink repellent layer. If the score is 3 or more, it can be used without any practical problem.

[Example 1]
A lithographic printing plate precursor was prepared by the following method.

  The following organic layer composition was applied on an aluminum substrate (manufactured by Norsk Hydro) having a thickness of 0.27 mm, and dried at 210 ° C. for 86 seconds in a safety oven “SPH-200” (manufactured by Espec Corporation) to obtain a thickness of 7 mm. An organic layer of 0.4 μm was provided. The organic layer composition was obtained by stirring and mixing the following components at room temperature.

<Organic layer composition>
(A) Polymer having active hydrogen: epoxy resin: “Epicoat” (registered trademark) 1010 (manufactured by Japan Epoxy Resin Co., Ltd.): 30.4 parts by mass (b) Polymer having active hydrogen: polyurethane: “Samprene” ( (Registered trademark) LQ-T1331D (manufactured by Sanyo Chemical Industries, Ltd., solid content concentration: 20% by mass): 57.3 parts by mass (c) Aluminum chelate: aluminum chelate ALCH-TR (manufactured by Kawaken Fine Chemical Co., Ltd.): 6.2 parts by mass (d) Leveling agent: "DISPARON" (registered trademark) LC951 (manufactured by Kusumoto Kasei Co., Ltd., solid content: 10% by mass): 0.1 part by mass (e) Titanium oxide: "Taipek" ( N, N-dimethylformamide dispersion (registered trademark) CR-50 (manufactured by Ishihara Sangyo Co., Ltd.) (titanium oxide: 50% by mass): 6.0 parts by mass (f) N, N-dimethylforme Amide: 450 parts by weight (g) Methyl ethyl ketone: 150 parts by weight.

  In addition, the compounding quantity of each component of the said organic layer composition was shown as a mass part with respect to 100 mass parts in total of the compounding quantity of component (a)-(e).

  Next, the following heat-sensitive layer composition-1 was applied on the organic layer, and dried by heating at 140 ° C. for 80 seconds to provide a heat-sensitive layer having a thickness of 1.0 μm. In addition, the thermosensitive layer composition-1 was obtained by the following preparation method.

<Thermosensitive layer composition-1>
29.7 g of a mixed acid (mass ratio of sulfuric acid / nitric acid = 3/1) was added to a 100 mL flask, and (a) multi-walled carbon nanotubes (diameter: 20-40 nm, length: 5-15 μm) (Tokyo Kasei Kogyo Co., Ltd.) Was mixed at a concentration of 1.0% by mass, the temperature was adjusted to 60 ° C., and the mixture was reacted for 24 hours. The resulting multi-walled carbon nanotube dispersion solution was filtered using filter paper (PTFE, pore size: 1.0 μm) (manufactured by ADVANTEC), and the carbon nanotubes on the filter paper were sufficiently washed with water, and then added to a 50 mL screw tube. Further, 20 g of tetrahydrofuran (hereinafter “THF”) was added, and ultrasonic irradiation was performed for 2 hours using an ultrasonic homogenizer “Digital Sonifier” (manufactured by BRANSON) to obtain a heat-sensitive layer composition-1.

  Then, the following ink repellent layer composition prepared immediately before application is applied on the heat-sensitive layer, and heated at 140 ° C. for 70 seconds to provide an ink repellent layer that is also a silicone rubber layer having an average film thickness of 2.1 μm. Lithographic printing plate precursor-1 was obtained. The ink repellent layer composition was obtained by stirring and mixing the following components at room temperature.

<Ink repellent layer composition>
(A) α, ω-divinylpolydimethylsiloxane: DMS-V35 (weight average molecular weight 49,500, manufactured by GELEST Inc.): 86.95 parts by mass (b) Polymethylhydrogensiloxane RD-1 (Dow Corning Toray) 4.24 parts by mass (c) Vinyl tris (methylethylketooxyimino) silane: 2.64 parts by mass (d) Platinum catalyst solution, SRX212 (manufactured by Dow Corning Toray Co., Ltd.) 0% by mass): 6.17 parts by mass (e) "ISOPAR" E (manufactured by Esso Chemical Co., Ltd.): 900 parts by mass The amount of the components (a) to (d) of the ink repellent layer composition-1 The total is 100 parts by mass.

  When the obtained lithographic printing plate precursor-1 was exposed and developed by the above-described method, the sensitivity of the precursor was 250 mW with a 780 nm laser, 250 mW with a 980 nm laser, 250 mW with a 1064 nm laser, and the adhesive force with the ink repellent layer was Three points were obtained, and good results were obtained.

[Example 2]
A lithographic printing plate precursor-2 was obtained in the same manner as in Example 1, except that the heat-sensitive layer composition-1 was changed to the following heat-sensitive layer composition-2. In addition, the thermosensitive layer composition-2 was obtained by the following preparation method.

<Thermosensitive layer composition-2>
To a 100 mL flask, 29.7 g of a mixed acid (mass ratio of sulfuric acid / nitric acid = 3/1) was added, and (a) single-walled carbon nanotubes (diameter: 0.9-1.7 nm, length: 0.3- 4 μm) (manufactured by NanoIntegris Co., Ltd.) was mixed in an amount of 0.3 g so as to have a concentration of 1.0% by mass, and the temperature was adjusted to 60 ° C. and reacted for 24 hours. The obtained single-walled carbon nanotube dispersion solution was filtered using filter paper (PTFE, pore size: 1.0 μm) (manufactured by ADVANTEC), and the carbon nanotubes on the filter paper were sufficiently washed with water, and then placed in a 50 mL screw tube. In addition, 20 parts by mass of THF was further added, and ultrasonic irradiation was performed for 2 hours using an ultrasonic homogenizer “Digital Sonifier” (manufactured by BRANSON) to obtain a heat-sensitive layer composition-2.

  When the obtained planographic printing plate precursor-2 was evaluated by the above method, the sensitivity of the precursor was 200 mW with a 780 nm laser, 200 mW with a 980 nm laser, 200 mW with a 1064 nm laser, and the adhesive force with the ink repellent layer was 3 points. And good results were obtained.

[Example 3]
Lithographic printing plate precursor-3 was obtained in the same manner as in Example 1 except that the heat-sensitive layer composition-1 was changed to the following heat-sensitive layer composition-3. In addition, the thermosensitive layer composition-3 was obtained by the following preparation method.

<Thermosensitive layer composition-3>
To a 50 mL screw tube, 0.3 g of ethylcellulose "Ethocel" Premium (viscosity: 100 cps) (manufactured by Nissin Kasei Co., Ltd.) and 29.7 g of THF were added, and the mixture was stirred at room temperature for 1 hour to obtain an ethylcellulose / THF solution. To 30 g of this ethyl cellulose / THF solution, 0.1 g of single-walled carbon nanotubes (diameter: 0.9-1.7 nm, length: 0.3-4 μm) (manufactured by NanoIntegris Inc.) was added, and an ultrasonic homogenizer was added. Ultrasonic treatment was performed for 2 hours using Digital Sonifier "(manufactured by BRANSON) to obtain a heat-sensitive layer composition-3.

  When the obtained lithographic printing plate precursor-3 was evaluated by the above-mentioned method, the sensitivity of the precursor was 175 mW with a 780 nm laser, 175 mW with a 980 nm laser, 175 mW with a 1064 nm laser, and an adhesive force with the ink repellent layer of 4 points. And very good results were obtained.

[Example 4]
After applying the organic layer in the same manner as in Example 1, the thermosensitive layer was applied in the same manner as in Example 1 using the thermosensitive layer composition-2. Next, the following adhesive layer composition-1 was applied on the heat-sensitive layer, and dried by heating at 140 ° C. for 80 seconds to provide an adhesive layer having a thickness of 0.3 μm. Subsequently, a planographic printing plate precursor-4 was obtained by providing an ink repellent layer in the same manner as in Example 1. In addition, the adhesive layer composition-1 was obtained by stirring and mixing the following components at room temperature.
<Adhesive layer composition-1>
(A) Imino group type methylated melamine resin: “CYMEL” 325 (manufactured by Allnex, viscosity: 2500 to 4500 mPa · s): 95.0 parts by mass (b) Sulfonic acid compound: p-toluenesulfonic acid: 5.0 mass Part (c) THF: 900 parts by mass.
The total of the components (a) and (b) in the adhesive layer composition was 100 parts by mass.

  When the obtained lithographic printing plate precursor-4 was evaluated by the above-described method, the sensitivity of the precursor was 225 mW with a 780 nm laser, 225 mW with a 980 nm laser, 225 mW with a 1064 nm laser, and an adhesive force with the ink repellent layer of 5 points. And good results were obtained.

[Example 5]
After applying the organic layer in the same manner as in Example 1, the thermosensitive layer was applied in the same manner as in Example 1 using the thermosensitive layer composition-3. Then, a lithographic printing plate precursor-5 was obtained by providing an adhesive layer and an ink repellent layer in the same manner as in Example 4.

  When the obtained lithographic printing plate precursor-5 was evaluated by the above method, the sensitivity of the precursor was 200 mW with a 780 nm laser, 200 mW with a 980 nm laser, 200 mW with a 1064 nm laser, and an adhesive force with the ink repellent layer of 5 points. And very good results were obtained.

[Comparative Example 1]
A lithographic printing plate precursor-6 was obtained in the same manner as in Example 1, except that the heat-sensitive layer composition-1 was changed to the following heat-sensitive layer composition-4.
<Thermosensitive layer composition-4>
(A) Phenol formaldehyde novolak resin: "Sumilite Resin" (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 72.9 parts by mass (b) Polyurethane: "SAMPLEN" (registered trademark) LQ-T1333 (Sanyo Chemical Industries, Ltd.) (C): 12.1 parts by mass (c) Titanium chelate: "Nasem" (registered trademark) titanium (manufactured by Nippon Chemical Industry Co., Ltd.): 15.0 parts by mass (e) THF: 614 parts by mass (f ) T-butanol: 207 parts by mass (g) N, N-dimethylformamide: 18 parts by mass (h) ethanol: 61 parts by mass The amount of each component of the thermosensitive layer composition is as follows: It was shown as parts by mass with respect to 100 parts by mass of the compounding amount of c).

  When the obtained lithographic printing plate precursor-6 was evaluated by the above-mentioned method, the sensitivity of the precursor was> 300 mW with a 780 nm laser,> 300 mW with a 980 nm laser,> 300 mW with a 1064 nm laser, and an adhesive force with the ink repellent layer. Was 5 points, which was impractical in terms of sensitivity.

[Comparative Example 2]
A lithographic printing plate precursor-7 was obtained in the same manner as in Example 1, except that the heat-sensitive layer composition-1 was changed to the following heat-sensitive layer composition-5.
<Thermosensitive layer composition-5>
(A) Phenol formaldehyde novolak resin: "Sumilite Resin" (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 65.6 parts by mass (b) Polyurethane: "Samprene" (registered trademark) LQ-T1333 (Sanyo Chemical Co., Ltd.) 11.0 parts by mass (c) Near infrared absorbing dye: "YKR2016" (manufactured by Yamamoto Kasei Co., Ltd.): 10.0 parts by mass (d) Titanium chelate: "Nasem" (registered trademark) Titanium (manufactured by Nippon Chemical Industry Co., Ltd.): 13.4 parts by mass (e) THF: 614 parts by mass (f) t-butanol: 207 parts by mass (g) N, N-dimethylformamide: 18 parts by mass (h) Ethanol: 61 parts by mass The amount of each component of the thermosensitive layer composition is shown as parts by mass with respect to 100 parts by mass of components (a) to (d).

  When the obtained lithographic printing plate precursor-7 was evaluated by the above method, the sensitivity of the precursor was 150 mW with a 780 nm laser,> 300 mW with a 980 nm laser,> 300 mW with a 1064 nm laser, and the adhesive force with the ink repellent layer was Five points were obtained, and the result was impractical in terms of sensitivity at 980 nm and 1064 nm lasers.

[Comparative Example 3]
A lithographic printing plate precursor-8 was obtained in the same manner as in Example 5, except that the heat-sensitive layer composition-3 was changed to the following heat-sensitive layer composition-6. In addition, the thermosensitive layer composition-6 was obtained by stirring and mixing the following components at room temperature.
<Thermosensitive layer composition-6>
(A) Polyester resin: "Byron 300" (manufactured by Toyobo Co., Ltd.): 40.0 parts by mass (b) Carbon black: "MOGUL L" (manufactured by CABOT Co., Ltd.): 33.0 parts by mass (c) Modified Epoxy resin: "EPOKEY" 803 (manufactured by Mitsui Toatsu Chemicals, Inc.): 20.0 parts by mass (d) Diethylenetriamine: 7.0 parts by mass (e) Methyl isobutyl ketone: 600 parts by mass The above-mentioned heat-sensitive layer composition Of the components (a) to (d) is 100 parts by mass.

  When the obtained lithographic printing plate precursor-8 was evaluated by the above method, the sensitivity of the precursor was> 300 mW with a 780 nm laser,> 300 mW with a 980 nm laser,> 300 mW with a 1064 nm laser, and an adhesive force with the ink repellent layer. Was 5 points, which was impractical in terms of sensitivity.

  Table 1 summarizes the results of these examples and comparative examples.

Claims (8)

A lithographic printing plate precursor comprising a substrate, a heat-sensitive layer containing carbon nanotubes, and an ink repellent layer in this order. The lithographic printing plate precursor according to claim 1, wherein the carbon nanotube is a single-walled carbon nanotube. The lithographic printing plate precursor according to claim 1, wherein the heat-sensitive layer contains a polymer having active hydrogen. The lithographic printing plate precursor according to any one of claims 1 to 3, further comprising an adhesive layer between the heat-sensitive layer and the ink repellent layer. The lithographic printing plate precursor according to claim 4, wherein the adhesive layer contains a polymer having active hydrogen. For the lithographic printing plate precursor according to any one of claims 1 to 5,
(A) a step of exposing according to a desired image, and then (B) a step of applying friction to the exposed lithographic printing plate precursor to remove an ink repellent layer, or (C) exposing according to a desired image and repelling ink. A method for producing a lithographic printing plate having a step of removing a layer. A printed matter is produced, comprising: a step of applying ink to the surface of a lithographic printing plate obtained by the method of producing a lithographic printing plate according to claim 6, and a step of transferring the ink to a printing medium directly or via a blanket. how to. For the lithographic printing plate precursor according to any one of claims 1 to 5,
(A) a step of exposing according to a desired image, and then (B) a step of applying friction to the exposed original plate to remove an ink repellent layer, or (C) exposing according to a desired image to remove the ink repellent layer. Process,
To get a lithographic printing plate,
A method for producing a printed material by a step of attaching ink to the surface of the lithographic printing plate, and a step of transferring the ink to a printing medium directly or via a blanket.