JP2012068423A - Photosensitive resin printing plate precursor and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin printing plate precursor which enhances both drawing sensitivity and shading property of a thermosensitive mask layer.SOLUTION: A photosensitive resin printing plate precursor has at least a photosensitive resin layer (A) and a thermosensitive mask layer containing pigment (B) on a support in this order. The thermosensitive mask layer containing pigment (B) satisfies a formula: OD(UV)/OD(K)≥1.2.

Description

  The present invention relates to a photosensitive resin printing plate precursor and a method for producing the same. More specifically, the present invention relates to a photosensitive resin printing plate precursor used for producing a resin relief printing plate by computer plate making technology and a method for producing the same.

  In various printing fields, computer plate making technology (computer-to-plate (CTP) technology) known as digital image forming technology has become common. As one of the CTP technologies, a thermal mask layer that is opaque to ultraviolet light is provided in advance on a photosensitive resin layer, and the thermal mask layer is ablated by irradiating the thermal mask layer with an infrared laser. There is a method of forming.

  As a photosensitive resin printing plate precursor used in CTP technology, on a support, a photosensitive resin layer containing a resin that can be dissolved or dispersed in water and a monomer curable by ultraviolet light, and water containing an infrared absorbing material There has been proposed a photosensitive resin printing plate precursor in which insoluble heat-sensitive mask layers are laminated in this order (see, for example, Patent Document 1). Further, a relief printing plate having a substrate, a layer crosslinkable by actinic radiation, an infrared sensitive layer, and a peelable protective layer in order, the infrared sensitive layer exhibiting an optical density of 2.5 or more in the actinic radiation range (for example, Patent Document 2), or a photosensitive relief printing original plate in which at least a support, a photosensitive resin layer, and a thermal mask layer are sequentially laminated, and the thermal mask layer is carbon black and a butyral resin as a dispersion binder thereof, In addition, a photosensitive relief printing original plate (for example, see Patent Document 3) characterized by containing a polar group-containing polyamide has been proposed.

JP 2004-163925 A JP-A-9-171247 Japanese Patent No. 4247725

  The photosensitive resin printing plate precursor used in the CTP technique controls the curing reaction by providing a heat-sensitive mask layer that blocks ultraviolet light on the photosensitive resin layer that is cured by ultraviolet light. An image is drawn in advance on the heat-sensitive mask layer before the exposure step of irradiating with ultraviolet light. In the portion where the heat-sensitive mask layer has been ablated, ultraviolet light reaches the photosensitive resin layer in the exposure process and is cured. On the other hand, in the portion where the thermal mask layer is not ablated, the ultraviolet light is shielded and the photosensitive resin layer is not cured. When the light-shielding property of the heat-sensitive mask layer is low, ultraviolet light is transmitted through the photosensitive resin layer, unintended portions are cured (exposure), and a good printing plate cannot be obtained. Therefore, the light-sensitive mask layer is required to have sufficient light shielding properties. On the other hand, when the heat-sensitive mask layer is thickened, the light shielding property is improved, but the drawing sensitivity is lowered, and the drawing time is increased, that is, the trade-off problem that productivity is lowered occurs.

  In view of the above problems, an object of the present invention is to provide a photosensitive resin printing plate precursor that achieves both high drawing sensitivity and light shielding properties of a heat-sensitive mask layer.

  In order to solve the above problems, the present invention mainly has the following configuration. That is, a photosensitive resin printing plate precursor having, in this order, at least a photosensitive resin layer (A) and a thermal mask layer (B) containing a pigment on a support, the thermal mask layer containing the pigment ( B) is a photosensitive resin printing plate precursor characterized by satisfying OD (UV) / OD (K) ≧ 1.2.

  According to the present invention, it is possible to obtain a photosensitive resin printing plate precursor that achieves both high drawing sensitivity and light shielding properties of the heat-sensitive mask layer. According to the photosensitive resin printing plate precursor of the present invention, it is possible to form a relief image without the need for an original film, reduce the occurrence of exposure defects in the plate making process, and maintain high drawing sensitivity. can do. For this reason, a high-quality printed matter can be obtained easily.

  Embodiments of the present invention will be described below.

  The photosensitive resin printing plate precursor of the present invention has at least a photosensitive resin layer (A) and a thermal mask layer (B) in this order on a support. Each layer may have two or more layers.

  Although the raw material used for the support body in this invention is not specifically limited, A dimensionally stable thing is used preferably. For example, metal plates such as steel, stainless steel and aluminum, polyester (for example, PET (polyethylene terephthalate), PBT (polybutylene terephthalate, PAN (polyacrylonitrile)), plastic films such as polyvinyl chloride, and these are reinforced with glass fibers. And synthetic rubbers such as styrene-butadiene rubber, etc. Among these, PET films and steel plates are preferably used.

  What is necessary is just to use the form of a support body according to whether the photosensitive resin layer (A) is a sheet form or a sleeve form. Moreover, in order to improve adhesiveness with the photosensitive resin layer (A), you may have an adhesive layer on the surface. Although the thickness of a support body is not specifically limited, 50 micrometers-1 mm are preferable from the surface of handling.

  The photosensitive resin layer (A) in the present invention refers to a layer that is photocured by irradiation with light having a wavelength of 300 nm to 500 nm, preferably 300 nm to 400 nm. It is preferable to contain at least a carrier resin, an ethylenically unsaturated monomer, and a photopolymerization initiator.

  The carrier resin in the photosensitive resin layer (A) is generally properly used depending on the ink used. In the case of printing plate precursors used for flexographic printing plates using water-based inks or UV inks, butadiene rubber, nitrile rubber, urethane rubber, isoprene rubber, acrylic rubber, epichlorohydrin rubber, styrene-butadiene copolymer are used as carrier resins. Elastomers such as copolymers of dienes such as styrene-isoprene copolymer, butadiene-acrylic acid copolymer, copolymers of olefins such as ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, etc. used. In the case of printing plate precursors used for letter press plates using oil-based inks or UV inks, polyvinyl alcohol, polyvinyl acetate, partially saponified polyvinyl acetate (partially saponified polyvinyl alcohol), cellulose resin, acrylic resin, polyethylene oxide, etc. Examples thereof include polyamide resins into which hydrophilic groups have been introduced, ethylene / vinyl acetate copolymers, and modified products of these resins. Two or more of these may be contained. Among these, water-developability can be imparted by using a hydrophilic resin as a carrier resin, so that polyvinyl alcohol, partially saponified polyvinyl alcohol, a polyamide resin having a hydrophilic group introduced therein, and modified products of these resins are provided. Preferably used.

  The content of the carrier resin is preferably 10% by weight or more, and more preferably 30% by weight or more in the total solid content of the photosensitive resin layer (A). Moreover, 80 weight% or less is preferable and 70 weight% or less is more preferable. If the content of the carrier resin is within such a range, the flexibility, printing durability, and developability of the printing plate can be achieved in an appropriate range.

  The ethylenically unsaturated monomer in the photosensitive resin layer (A) is a compound that can be cross-linked by radical polymerization. Although it will not specifically limit if it is a compound which can be bridge | crosslinked by radical polymerization, Generally, the compound which has an acryl group and / or a methacryl group can be mentioned. Specifically, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, β-hydroxy-β '-(Meth) acryloyloxyethyl phthalate and other hydroxyl group-containing (meth) acrylates, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isoamyl (meth) acrylate, 2 -Ethylhexyl (meth) acrylate, lauryl (meth) acrylate, alkyl (meth) acrylate such as stearyl (meth) acrylate, cycloalkyl (meth) acrylate such as cyclohexyl (meth) acrylate, chloroe Alkyl alkyl (meth) acrylates such as chill (meth) acrylate and chloropropyl (meth) acrylate, alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, and butoxyethyl (meth) acrylate , Phenoxyalkyl (meth) acrylates such as phenoxyethyl acrylate, nonylphenoxyethyl (meth) acrylate, alkoxyalkylene glycols such as ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate (Meth) acrylate, (meth) acrylamide, diacetone (meth) acrylamide, N, N′-methylenebis (Meth) acrylamides such as (meth) acrylamide, 2,2-dimethylaminoethyl (meth) acrylate, 2,2-diethylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N- Compounds having only one ethylenically unsaturated bond such as dimethylaminopropyl (meth) acrylamide, polyethylene glycol di (meth) acrylate such as diethylene glycol di (meth) acrylate, polypropylene glycol such as dipropylene glycol di (meth) acrylate Di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol tri (meth) Such as polyvalent (meth) acrylates and glycidyl (meth) acrylates obtained by addition reaction of acrylates, ethylene glycol diglycidyl ether with compounds with ethylenically unsaturated bonds and active hydrogen such as unsaturated carboxylic acids and unsaturated alcohols Multivalent (meth) acrylamides such as polyvalent (meth) acrylates and methylenebis (meth) acrylamides obtained by addition reaction of unsaturated epoxy compounds with compounds having active hydrogen such as carboxylic acids and amines, and polyvalents such as divinylbenzene Examples thereof include compounds having two or more ethylenically unsaturated bonds, such as vinyl compounds. Two or more of these may be contained. In the text, (meth) acrylate means acrylate or methacrylate, and (meth) acryl means acryl or methacryl.

  The content of the ethylenically unsaturated monomer is preferably 10% by weight or more, and more preferably 15% by weight or more in the total solid content of the photosensitive resin layer (A). If the content of the ethylenically unsaturated monomer is 10% by weight or more, a cross-linked structure is sufficiently formed by photopolymerization, and it is difficult to swell against the diluted solvent or diluted monomer of the ink, and the solid part is swollen during printing. Destruction and printing defects can be suppressed. On the other hand, 80 weight% or less is preferable and 55 weight% or less is more preferable. By setting the content of the ethylenically unsaturated monomer to 80% by weight or less, since the crosslinking density formed by photopolymerization does not become excessive, it is possible to suppress cracks in the relief during printing.

  The photopolymerization initiator in the photosensitive resin layer (A) is not particularly limited as long as it can polymerize a polymerizable carbon-carbon unsaturated group by light. Especially, what has the function to produce | generate a radical by self-cleavage or hydrogen abstraction by light inhalation is preferable. Examples of such photopolymerization initiators include benzoin alkyl ethers, benzophenones, anthraquinones, benzyls, acetophenones, diacetyls, and the like. Two or more of these may be contained.

  The content of these photopolymerization initiators is preferably 0.01% by weight to 10% by weight in the total solid content of the photosensitive resin layer.

  The photosensitive resin layer (A) may contain, as other components, polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, trimethylolpropane, and trimethylolethane. Solubility and flexibility can be improved. Further, for example, a conventionally known polymerization inhibitor such as phenols, hydroquinones, catechols and the like may be contained, and the thermal stability can be improved. Moreover, dye, a pigment, surfactant, a ultraviolet absorber, a fragrance | flavor, antioxidant, etc. can also be contained.

  The film thickness of the photosensitive resin layer varies depending on the substrate to be printed, the printing press, letterpress plate or flexographic plate, but is preferably 0.2 mm to 6.0 mm. By setting the thickness to 0.2 mm or more, it is possible to easily form unevenness with a level difference sufficient to form a relief printing plate. On the other hand, when the thickness is 6.0 mm or less, not only because it is advantageous in terms of the cost of the plate material, but also the weight of the printing plate can be suppressed, and handling becomes easy. The film thickness of the photosensitive resin layer can be measured by, for example, a palpation type film thickness measuring device (for example, a micrometer).

  The heat-sensitive mask layer (B) in the present invention (1) has a function of practically shielding ultraviolet light, and (2) absorbs an infrared laser efficiently, and a part of the layer is instantaneously generated by the heat. Alternatively, all of them are evaporated or ablated, and the optical density of the ultraviolet light is different between the irradiated part and the unirradiated part of the laser, that is, the optical density of the ultraviolet light is lowered in the irradiated part.

The optical density is generally expressed by OD defined by the following formula, and refers to the absorbance with respect to light of a certain wavelength.
OD = log ₁₀ (100 / T) = log ₁₀ (I ₀ / I)
(Here, T is the transmittance (unit:%), I ₀ is the incident light intensity when measuring the transmittance, and I is the transmitted light intensity.)

  For optical density measurement, there are known methods of calculating from the measured value of transmitted light intensity with a constant incident light intensity and calculating from the measured value of incident light intensity required to reach a certain transmitted light intensity. However, the optical density in the present invention is a value calculated from the former transmitted light intensity. The optical density can be measured in a transmission mode with a Macbeth transmission densitometer “TR-927” (manufactured by Kolmorgen Instruments Corp.). The light source of incident light has a function of limiting the wavelength by a lamp light source through filters of each color. For example, the transmission density OD (K) with respect to the total light source can be measured through an orthochromatic filter. The transmission density OD (UV) with respect to ultraviolet light can be measured through a UV filter.

  OD (K) has high measurement accuracy due to strong incident light intensity of the light source, and is commonly used to measure the black density of black bodies such as silver salt films. There are many cases to say. On the other hand, OD (UV) directly measures the shielding property against ultraviolet light. In the present invention, focusing on OD (K) and OD (UV), a thermal mask layer (B) having a higher OD (UV) than OD (K) is proposed.

  The total light (K) mainly consists of visible light (VIS) and ultraviolet light (UV). When the absorbance is expressed by OD (K), OD (VIS), and OD (UV), OD (K) is It is a weighted average value of OD (VIS) and OD (UV). For a layer having the same absorbance (or transmittance) for each wavelength of visible light to ultraviolet light, the relationship of OD (VIS) = OD (UV), that is, OD (K) = OD (UV) is established. The shielding property against ultraviolet light can be evaluated by OD (K). A silver halide negative film or a heat sensitive mask layer containing ordinary carbon black applies to this. On the other hand, in the case of a layer having absorbance dependency with respect to the wavelength of light, for example, in the case of a layer having low absorbance for visible light and high absorbance for ultraviolet light, OD (UV)> OD (K)> OD (VIS) Become. That is, the present invention proposes a heat-sensitive mask layer (B) with improved ultraviolet light shielding properties by designing such a layer.

  As one method for improving the light shielding property of the thermal mask layer (B), it is conceivable to increase the thickness of the thermal mask layer (B). However, in this case, there is a problem that drawing sensitivity is lowered and productivity is lowered. Since OD (UV) and OD (K) are both proportional to the film thickness of the thermal mask layer (B), the OD (K) increases when the thermal mask layer (B) is thickened. The present invention aims to increase the function of the heat-sensitive mask layer (B) to block ultraviolet light while reducing the OD (K) as small as possible in order to realize high drawing sensitivity. In other words, the heat-sensitive mask layer (B) satisfying OD (UV) / OD (K) ≧ 1.2 can achieve both high ultraviolet light shielding properties and drawing sensitivity. It is more preferable that OD (UV) / OD (K) ≧ 1.3.

  Ultraviolet light is irradiated from an exposure machine that is generally used in the exposure step. Among them, 365 nm can be given as an example of the wavelength of light suitable for curing the photosensitive resin layer (A). Since the refractive index of a general resin used for the thermal mask layer (B) is about 1.5, light having a wavelength of 365 nm can be calculated as a wavelength of about 240 nm in the thermal mask layer (B). The heat-sensitive mask layer (B) in the present invention contains a pigment. Particularly, by containing a pigment having a particle size of 240 nm or more, the light-shielding property against ultraviolet light used in the exposure step, at least 365 nm ultraviolet light can be improved. . In order to form a uniform heat-sensitive mask layer (B), a certain degree of pigment miniaturization is necessary, and it is preferable to appropriately manage the particle size distribution of the pigment. In the present invention, in the particle size distribution of the pigment, the pigment having a particle size of 240 nm or more is preferably 20% or more, and the drawing sensitivity and the light shielding property can be compatible at a higher level. More preferably, it is 30% or more. Here, the particle size refers to the diameter of secondary particles in which pigments are aggregated. The particle size distribution of the pigment in the heat-sensitive mask layer is determined by observing the heat-sensitive mask layer at 250 times with an electron microscope and measuring the diameter of 12 or more spherical particles (secondary particles) observed in the field of view. . % In the particle size distribution means number%. Further, in the particle size distribution of the pigment, it is preferable to have a maximum value in the range of 150 nm to 300 nm. It is more preferable to have a maximum value in the range of 200 nm to 250 nm.

  The method for obtaining the pigment having the particle size distribution is not particularly limited. For example, by reaggregating the pigment once finely dispersed, a uniform film can be applied and the pigment coating agent having the particle size distribution is obtained. be able to. Moreover, it can also be achieved by a method in which the number of stirring is excessive in the preparation of the pigment coating, or a method in which the pigment coating is heated.

  The pigment in the heat-sensitive mask layer (B) is not particularly limited, but is preferably an ultraviolet light-shielding compound having absorption in a wavelength region of at least 300 nm to 400 nm. For example, black pigments such as benzotriazole compounds, triazine compounds, carbon black, aniline black, cyanine black, carbon graphite, diamine metal complexes, dithiol metal complexes, phenol thiol metal complexes, mercaptophenol metal complexes, Aryl aluminum metal salts, inorganic compounds containing crystal water, copper sulfate, chromium sulfide, silicate compounds, metal oxides such as titanium oxide, vanadium oxide, manganese oxide, iron oxide, cobalt oxide, tungsten oxide, hydroxylation of these compounds Products, sulfates, and metal compounds such as bismuth, tin, tellurium, iron and aluminum metal powders. Two or more of these may be contained. Among these, carbon black is particularly preferable from the viewpoints of ultraviolet shielding properties, economy, handling properties, and infrared light heat conversion function described later. Carbon black is classified into furnace black, channel black, thermal black, acetylene black, lamp black, etc., depending on its production method. Furnace black is commercially available in various specifications in terms of particle size and other aspects. In view of its low cost, it is preferably used.

  The content of the pigment in the heat-sensitive mask layer (B) is preferably 5% by weight or more, more preferably 20% by weight or more, based on the total solid content of the heat-sensitive mask layer (B), from the viewpoint of further improving the ultraviolet light shielding property. . On the other hand, from the viewpoint of scratch resistance of the thermal mask layer (B), it is preferably 75% by weight or less, and more preferably 70% by weight or less.

  The heat-sensitive mask layer (B) contains a pigment that is an ultraviolet light shielding material in order to obtain the function (1), but in order to obtain the function (2), an infrared absorbing material that converts infrared light into photothermal energy. Containing. Moreover, in order to improve the drawing sensitivity with respect to an infrared laser, a thermally decomposable compound that is evaporated or ablated by heat may be contained.

  The infrared absorbing substance is not particularly limited as long as it is a substance that can absorb infrared light and convert it into heat. For example, black pigments such as carbon black, aniline black, and cyanine black, green pigments such as phthalocyanine and naphthalocyanine, rhodamine dyes, naphthoquinone dyes, polymethine dyes, diimonium salts, azoimonium dyes, chalcogen dyes, and UV shielding properties Examples thereof include metal compounds exemplified as the pigments. Two or more of these may be contained. Among these, carbon black is particularly preferable from the viewpoints of photothermal conversion efficiency, economy, handleability, and ultraviolet light shielding properties described above.

  In the present invention, the content of the infrared absorbing material in the heat-sensitive mask layer (B) is preferably 5% by weight or more, and more preferably 20% by weight or more in the total solid content of the heat-sensitive mask layer (B) from the viewpoint of photothermal conversion efficiency. More preferred. On the other hand, from the viewpoint of scratch resistance of the thermal mask layer (B), it is preferably 75% by weight or less, and more preferably 70% by weight or less.

  Examples of the thermally decomposable compounds include polymer compounds and nitro compounds that are easily thermally decomposed, organic peroxides, azo compounds, diazo compounds, hydrazine derivatives, and metal compounds exemplified as ultraviolet shielding pigments. . Two or more of these may be contained.

  From the viewpoint of coatability, a polymer compound is preferable, and examples thereof include an acrylic resin. Acrylic resins are relatively easy to thermally decompose, and the general thermal decomposition temperature of acrylic resins is 190 ° C to 250 ° C. The acrylic resin refers to a polymer or copolymer of one or more monomers selected from the group consisting of acrylic acid, methacrylic acid, acrylic acid ester, and methacrylic acid ester. Among the acrylic resins, by selecting a grade that does not dissolve in water or alcohol, mass transfer to the lower photosensitive resin layer (A) can be suppressed. Therefore, a water / alcohol insoluble acrylic resin is more preferable. Used.

  In the present invention, the content of the thermally decomposable compound in the thermal mask layer (B) is preferably 50% by weight or less in the total solid content of the thermal mask layer (B).

  In the present invention, since the heat-sensitive mask layer (B) contains a pigment such as carbon black as an ultraviolet light shielding material or infrared absorbing material, a plasticizer, a surfactant or a dispersion is used to facilitate the dispersion. An auxiliary agent may be contained.

  The film thickness of the thermal mask layer (B) is preferably 0.5 to 5.0 μm. By setting the film thickness to 0.5 μm or more, the ultraviolet light shielding property can be further improved. On the other hand, when the film thickness is 5.0 μm or less, the drawing sensitivity can be further improved, which is advantageous in terms of production cost. Examples of the method for measuring the film thickness of the thermal mask layer include a method of measuring by a film weight per unit area and a method of measuring by a palpable film thickness measuring instrument (for example, a micrometer).

  The photosensitive resin printing plate precursor of the present invention has at least the heat-sensitive resin layer (A) and the heat-sensitive mask layer (B) in this order on a support. If necessary, an intermediate layer (C) may be provided between the heat-sensitive resin layer (A) and the heat-sensitive mask layer (B). Moreover, you may provide a cover film (D) further on a thermal mask layer (B).

  By having an intermediate | middle layer (C), the adhesiveness of a heat sensitive resin layer (A) and a heat sensitive mask layer (B) can be improved. Examples of the material used for the intermediate layer (C) include polyvinyl alcohol, partially saponified polyvinyl alcohol, polyamide having a hydrophilic group, and a mixture thereof.

  By having the cover film (D), the heat-sensitive mask layer (B) can be protected from trauma. The cover film (D) is preferably peelable from the heat-sensitive mask layer (B). For example, a release paper coated with a film such as polyester, polycarbonate, polyamide, fluoropolymer, polystyrene, polyethylene, or polypropylene, or silicone. Etc.

  The film thickness of the cover film (D) is preferably 25 μm or more, and more preferably 50 μm or more. When the film thickness is 25 μm or more, handling is easy, and the thermal mask layer (B) can be easily protected from external damage. Moreover, 200 micrometers or less are preferable and 150 micrometers or less are more preferable. A film thickness of 200 μm or less is advantageous in terms of production cost. The film thickness of the cover film (D) can be easily measured with a palpation-type film thickness measuring instrument (for example, a micrometer).

  The photosensitive resin printing plate precursor of the present invention may further have a peeling auxiliary layer (E) between the heat-sensitive mask layer (B) and the cover film (D). It is preferable that the peeling auxiliary layer (E) has a function of easily peeling only the cover film (D) or both the cover film (D) and the peeling auxiliary layer (E) from the photosensitive resin printing plate precursor. If the cover film (D) and the thermal mask layer (B) are directly laminated and the adhesive strength between the two layers is strong, the cover film (D) cannot be peeled off or may be peeled off together with the thermal mask layer (B). There is sex.

  Therefore, the peeling auxiliary layer (E) has a strong adhesive force with the thermal mask layer (B) and is weak enough to peel the adhesive force with the cover film (D), or with the thermal mask layer (B). It is preferable that the adhesive strength is weak enough to be peeled off and it is made of a substance having a strong adhesive strength with the cover film (D). In addition, after peeling a cover film (D), since a peeling auxiliary | assistant layer (E) may remain on the thermal mask layer (B) side and may become an outermost layer, it is preferable that it is not adhesive from the surface of handling. Moreover, since it exposes to ultraviolet light through a peeling auxiliary layer (E), it is preferable that it is substantially transparent.

  The material used for the peeling auxiliary layer (E) can be dissolved or dispersed in water, such as polyvinyl alcohol, polyvinyl acetate, partially saponified polyvinyl alcohol, hydroxyalkyl cellulose, alkyl cellulose, polyamide resin, and the like. It is preferable to use a small amount of resin as a main component. Among these, partially saponified polyvinyl alcohol having a saponification degree of 60 to 99 mol%, hydroxyalkyl cellulose having 1 to 5 carbon atoms in the alkyl group, and alkyl cellulose are particularly preferably used from the viewpoint of tackiness.

  The peeling auxiliary layer (E) may further contain an infrared absorbing material and / or a thermally decomposable compound in order to facilitate the ablation with infrared rays. As the infrared absorbing material and the thermally decomposable compound, those described above as the components of the thermal mask layer (B) can be used. Moreover, you may contain surfactant for coating property and wettability improvement.

  The film thickness of the peeling assist layer (E) is preferably 6 μm or less, and more preferably 3 μm or less, from the viewpoint of maintaining the laser ablation of the lower thermal mask layer (B). On the other hand, 0.03 μm or more is preferable from the viewpoint of easily forming the peeling assisting layer (E). The film thickness can be easily measured by the film weight per unit area.

  When the cover film (D) is peeled from the photosensitive resin printing plate precursor at a speed of 200 mm / min, the peel force per 1 cm width is preferably 0.5 g (0.49 N / m) or more, and preferably 1 g (0.98 N / m). m) or more is more preferable. If it is this range, peeling of the protective layer (D) during work can be suppressed. On the other hand, from the viewpoint of easily peeling the cover film (D), it is preferably 20 g (19.6 N / m) or less, and more preferably 15 g (14.7 N / m) or less.

  Next, the preferable manufacturing method of the photosensitive resin printing plate precursor of this invention is described. The method for producing a photosensitive resin printing plate precursor according to the invention includes at least a step of forming a photosensitive resin composition (A) on a support and a step of forming a heat-sensitive mask layer (B).

  First, as a method for forming the photosensitive resin layer (A) on the support, for example, after dissolving a carrier resin, if necessary, other resins in a solvent, an ethylenically unsaturated monomer, a photopolymerization initiator, and if necessary Other additives are added and sufficiently stirred to obtain a coating liquid composition for the photosensitive resin layer. After removing the solvent from the coating liquid composition for the photosensitive resin layer, preferably an adhesive is added. It can be obtained by melt extrusion onto a coated support. Alternatively, it can also be obtained by melt-extruding a coating liquid composition for a photosensitive resin layer in which a part of the solvent remains on a support coated with an adhesive and naturally drying the remaining solvent over time. be able to. Although the solvent used for the coating liquid composition for photosensitive resin layers will not be specifically limited if the component of the photosensitive resin layer (A) can be melt | dissolved, Water, alcohol, or these mixtures are used preferably.

  The method for forming the intermediate layer (C) on the photosensitive resin layer (A) or the heat-sensitive mask layer (B) is not particularly limited, but for the convenience of forming a thin film, a photosensitivity obtained by dissolving the intermediate layer (C) component in a solvent. The method of apply | coating the coating liquid composition for photosensitive resin layers on the photosensitive resin layer (A) or a thermal mask layer (B), and removing a solvent is used preferably. Although the solvent used for formation of an intermediate | middle layer (C) will not be specifically limited if an intermediate | middle layer (C) component can be melt | dissolved, Water, alcohol, or these mixtures are used preferably. When the heat-sensitive mask layer (B) is insoluble in water, even if the coating liquid composition for the photosensitive resin layer is applied onto the heat-sensitive mask layer (B) by using water or alcohol, the heat-sensitive mask layer ( B) is preferred because it is not eroded. Further, the boiling point of the solvent under atmospheric pressure is preferably 80 ° C. or higher from the viewpoint of suppressing volatilization during coating. On the other hand, 200 ° C. or lower is preferable from the viewpoint of easily removing the solvent.

  Next, as a method for forming the heat-sensitive mask layer (B), for example, a method of applying a coating liquid composition for a heat-sensitive mask layer containing a pigment on the photosensitive resin layer (A) can be mentioned. When the coating liquid composition contains a solvent, the solvent is removed after coating. Moreover, you may make it thermoset as needed. The coating composition for the thermal mask layer is prepared by, for example, preparing a dispersion in which a pigment such as carbon black is dispersed in a solvent or a resin, and using other components for the thermal mask layer as they are or in an appropriate solvent. It can be obtained by mixing with the dissolved solution. The solvent used for the formation of the thermal mask layer (B) is not particularly limited as long as the component of the thermal mask layer (B) can be dissolved or well dispersed, but the boiling point under atmospheric pressure is 80 ° C. or higher and 200 ° C. or lower. Those are preferred.

  The particle size distribution of the pigment in the heat-sensitive mask layer depends on the particle size distribution in the coating liquid composition. That is, since the particle size distribution of the pigment in the heat-sensitive mask layer is considered to be equivalent to the particle size distribution in the coating liquid composition, the pigment having a particle size of 240 nm or more in the particle size distribution of the pigment in the coating liquid composition. It is preferably 20% or more. In order to obtain such a particle size distribution, it is preferable to heat-treat the coating liquid composition for the heat-sensitive mask layer. The heating condition is preferably 1 hour or longer at 40 ° C., more preferably 2 days or longer at 50 ° C. The particle size distribution of the pigment in the coating liquid composition can be determined, for example, by a known particle size distribution measuring apparatus such as Microtrack 9340 upa manufactured by Nikkiso Co., Ltd.

  The method for forming the peeling auxiliary layer (E) on the heat-sensitive mask layer (B) or the cover film (D) is not particularly limited. However, for ease of thin film formation, the peeling auxiliary layer (E) component is dissolved in a solvent. The method of apply | coating the coating liquid composition for auxiliary layers on a heat-sensitive mask layer (B) or a cover film (D), and removing a solvent is used preferably. Although the solvent used for formation of a peeling auxiliary layer (E) will not be specifically limited if the peeling auxiliary layer (E) component can be melt | dissolved, Water, alcohol, or these mixtures are used preferably.

  By laminating the respective layers, the photosensitive resin printing plate precursor of the present invention can be obtained.

  The first example of the photosensitive resin printing plate precursor of the present invention is a photosensitive resin layer (A), an intermediate layer (C), a thermal mask layer (B), a peeling assist layer (E) and a cover film on a support. It is an original plate having a structure in which (D) is sequentially laminated. For example, a thermal mask sheet having a thermal mask layer (B) in which the layer (E), the layer (B) and the layer (C) are laminated by a sequential application method on the cover film (D), and a layer ( It can be obtained by laminating a photosensitive resin sheet laminated with A). The laminating method is not particularly limited. For example, the surface of the layer (A) or the layer (C) is swollen with water and / or alcohol, and the thermal mask sheet and the photosensitive resin sheet are bonded to each other, the layer (A) And a method of pouring a high-viscosity liquid having the same or similar composition between a photosensitive resin sheet and a heat-sensitive mask sheet and bonding them together, a method of pressing with a press machine at room temperature or while heating, and the like.

  The second example is an original having a structure in which a photosensitive resin layer (A), an intermediate layer (C), and a thermal mask layer (B) are sequentially laminated on a support. For example, the coating liquid composition for the layer (C) is applied to a photosensitive resin sheet in which the photosensitive resin layer (A) is laminated on the support, dried, and then for the thermal mask layer (B). This coating liquid composition can be applied and heated to be cured. As another method, a thermal mask sheet having a thermal mask layer (B) in which the layer (B) and the layer (C) are sequentially laminated on the release paper by the same coating method, and the layer (A) is laminated on the support. It can also be obtained by preparing a photosensitive resin sheet and then laminating both layers so that the layer (A) is in contact with the layer (C) and then peeling the release paper. The peeled release paper has the advantage that it can be reused for the same purpose.

  The third example is an original plate having a structure in which a photosensitive resin layer (A), an intermediate layer (C), a thermal mask layer (B), and a peeling auxiliary layer (E) are sequentially laminated on a support. This original plate can be obtained, for example, by peeling the cover film (D) from the original plate obtained in the first example. In this example, there is an advantage that the cover film (D) can be reused.

  The fourth example is an original having a structure in which a photosensitive resin layer (A), an intermediate layer (C), a thermal mask layer (B), and a cover film (D) are sequentially laminated on a support. For example, a thermal mask sheet in which layers (B) and (C) are sequentially laminated on a cover film (D) and a photosensitive resin sheet in which layers (A) are laminated on a support are laminated. Can be obtained by:

  The photosensitive resin printing plate precursor obtained as described above is at least (1) using the above-mentioned photosensitive resin printing plate precursor, and (2) imagewise irradiating the thermal mask layer (B) with an infrared laser. A step of forming an image mask (B ′) by (3) a step of exposing from the formed image mask (B ′) side using ultraviolet light to form a latent image on the photosensitive resin layer (A); 4) A resin relief printing plate can be manufactured through a process of developing and removing the image mask (B ′) and the photosensitive resin layer (A) in the ultraviolet unexposed area.

  When the layer (E) and / or the layer (D) is present, at least the layer (D) is peeled off, and then the thermal mask layer (B) is imagewise irradiated with an infrared laser to form an image mask. It is preferable to form (B ′). More preferably, after the layer (E) and the layer (D) are present, only the layer (E) is peeled off, and then an infrared laser is imaged in an image form on the thermal mask layer (B) through the layer (D). Irradiation to form an image mask (B ′).

  (2) The step of forming an image mask (B ′) by imagewise irradiating the thermal mask layer (B) with an infrared laser is to turn on / off the infrared laser based on the image data, It is a process of scanning irradiation with respect to B). When the thermal mask layer (B) is irradiated with an infrared laser, heat is generated by the action of the infrared absorbing substance, and the thermal decomposable compound is decomposed by the action of the heat to remove the thermal mask layer (B). Laser ablation. The laser ablated portion has a greatly reduced optical density and is substantially transparent to ultraviolet light. An image mask (B ′) capable of forming a latent image on the photosensitive resin layer (A) is obtained by selectively laser ablating the thermal mask layer (B) based on the image data.

  For the infrared laser irradiation, one having an oscillation wavelength in the range of 750 nm to 3000 nm is used. Examples of such lasers include ruby lasers, alexandrite lasers, perovskite lasers, solid state lasers such as Nd-YAG lasers and emerald glass lasers, semiconductor lasers such as InGaAsP, InGaAs and GaAsAl, and dye lasers such as rhodamine dyes. It is done. A fiber laser that amplifies these light sources with a fiber can also be used. Among them, the semiconductor laser is preferable because it is downsized due to recent technological advances and is economically advantageous over other laser light sources. An Nd-YAG laser is also preferable because it has a high output, is widely used for dentistry and medical purposes, and is economically inexpensive.

  (3) The step of exposing from the image mask (B ′) side using ultraviolet light to form a latent image on the photosensitive resin layer (A) is a photosensitive resin printing plate precursor irradiated with a laser by the above method. In addition, ultraviolet light, preferably ultraviolet light having a wavelength of 300 to 400 nm, is exposed on the entire surface through an image mask (B ′) on which an image is formed by a laser, and the lower part of the laser ablation part in the image mask (B ′) This is a step of selectively photocuring the photosensitive resin layer (A).

  During exposure, ultraviolet light also enters from the side surface of the photosensitive resin printing plate precursor. Therefore, it is preferable to cover the side surface with a cover that does not transmit ultraviolet light. As a light source capable of exposing a wavelength of 300 to 400 nm, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a xenon lamp, a carbon arc lamp, a chemical lamp, or the like can be used. The portion of the photosensitive resin layer (A) exposed with ultraviolet light is changed into a substance that cannot be eluted and dispersed by the developer.

  (4) The step of developing and removing the image mask (B ′) and the photosensitive resin layer (A) in the ultraviolet light unexposed area is, for example, a developer capable of dissolving or dispersing the photosensitive resin layer (A). It is achieved by developing using a brush type washing machine having When a hydrophilic resin is used as the carrier resin of the photosensitive resin layer (A), the developer is preferably one containing water as a main component. Through this step, a portion exposed to ultraviolet light remains, and a resin relief printing plate having a relief image is obtained. When the peeling auxiliary layer (E) remains, it is preferably removed in this development step.

  The developer containing water as a main component may contain tap water, distilled water, or water as a main component and an alcohol having 1 to 6 carbon atoms. Here, the main component means 70% by weight or more. Moreover, what mixed the component of the photosensitive resin layer (A), the intermediate | middle layer (C), the thermal mask layer (B), and the peeling auxiliary | assistant layer (E) in these liquids can also be used.

  Thereafter, if necessary, a treatment for drying the developer adhering to the plate surface, a post-exposure of the resin relief printing plate, an adhesive removal treatment, and the like can be performed.

  The resin relief printing plate produced using the photosensitive resin printing plate precursor of the present invention is preferably used as a resin relief printing plate that can be mounted on a printing machine.

  Evaluation in each Example and Comparative Example was performed by the following method.

<Particle size distribution of pigment in coating composition for thermal mask layer>
The coating liquid composition for the heat-sensitive mask layer was collected and measured using a Nikkiso Co., Ltd. particle size distribution measuring device Microtrac 9340 upa.

<Particle size distribution of the pigment in the thermal mask layer>
The heat-sensitive mask layer of the heat-sensitive mask element was observed with an electron microscope at 250 times, and the diameter was determined by measuring the diameter of 12 spherical particles (secondary particles) observed in the field of view.

<Optical density of thermal mask layer>
The measurement was performed using a Macbeth transmission densitometer “TR-927” (manufactured by Kolmorgen Instruments Corp.). An orthochromatic filter was used for OD (UV) measurement, and an ultra violet filter was used for OD (K) measurement. Both OD (UV) and OD (K) are randomly selected on the thermal mask layer of the thermal mask element of 5 cm square, or on the surface exposed by peeling the cover film (D) of the 5 cm square printing plate precursor. Three points were measured and the average value was calculated.

<Drawing sensitivity>
After peeling the cover film (D) from the photosensitive resin printing plate precursor, an external drum type plate setter “CDI SPARK” (manufactured by Esco Graphics Co., Ltd.) equipped with a fiber laser having a light emitting region in the infrared, The support was mounted so that the support side was in contact with the drum. An image having a test pattern having a resolution of 150 lines and a solid portion was drawn under the conditions of a laser output of 11.5 W and a drum rotation speed of 700 rpm. The surface of the drawn photosensitive resin printing plate precursor was observed with a magnifying glass, and the presence or absence of the drawing residue was observed. When the remaining drawing is not recognized, the drawing sensitivity is evaluated as ○ (drawing sensitivity is high), when the slight remaining drawing is recognized as △, and when the remaining drawing is recognized as × (drawing sensitivity is low). .

<Light shielding>
The relief of the printing plate was observed with a magnifying glass, and the presence or absence of exposure defects was observed. When no exposure defect was observed, the light shielding property was evaluated as high (◯), and when the exposure defect was observed, the light shielding property was evaluated as low (×).

<Synthesis Example 1: Synthesis of modified polyvinyl alcohol 1>
In a flask equipped with a condenser, partially saponified polyvinyl alcohol “GOHSENOL” (registered trademark) KL-05 (saponification degree measured by the method shown in JIS K6726 (1994) 78.5% to 82.0%, Nippon Synthetic Chemical Co., Ltd.) 50 parts by weight (manufactured by Kogyo Co., Ltd.), 2 parts by weight of succinic anhydride and 10 parts by weight of acetone were added and heated at 60 ° C. for 6 hours, and then the condenser was removed to volatilize the acetone. Thereafter, the purification step of eluting unreacted succinic anhydride with 100 parts by weight of acetone was carried out twice, followed by drying under reduced pressure at 60 ° C. for 5 hours to obtain modified polyvinyl alcohol 1 in which succinic acid was ester-bonded to a hydroxyl group. Obtained.

<Synthesis Example 2: Synthesis of water-soluble polyamide resin 1>
10 parts by weight of ε-caprolactam, 90 parts by weight of N- (2-aminoethyl) piperazine and nylon salt of adipic acid and 100 parts by weight of water were placed in a stainless steel autoclave, and the air inside was replaced with nitrogen gas at 180 ° C. The mixture was heated for 1 hour, and then water was removed to obtain a water-soluble polyamide resin 1.

<Synthesis Example 3: Synthesis of water-soluble polyamide resin 2>
60 parts by weight of an equimolar salt of α, ω-diaminopolyoxyethylene and adipic acid obtained by adding acrylonitrile to both ends of polyethylene glycol having a number average molecular weight of 600 and reducing this with hydrogen, and 20 parts by weight of ε-caprolactam And 20 parts by weight of an equimolar salt of hexamethylenediamine and adipic acid are melt-polymerized to give a water-soluble polyamide resin having a relative viscosity (viscosity of 1 g of polymer dissolved in 100 ml of chloral hydrate and measured at 25 ° C.) of 2.5. 2 was obtained. This water-soluble polyamide resin 2 has a polyethylene glycol segment which is a hydrophilic group in the main chain.

<Preparation of coating liquid composition 1 for photosensitive resin layer (A1)>
In a three-necked flask equipped with a stirring spatula and a condenser tube, 7.5 parts by weight of the water-soluble polyamide resin 1 obtained in Synthesis Example 2 and 47.5% by weight of the modified polyvinyl alcohol 1 obtained in Synthesis Example 1 11 parts by weight of diethylene glycol, 38 parts by weight of water and 44 parts by weight of ethanol were heated with stirring at 110 ° C. for 30 minutes and then at 70 ° C. for 90 minutes to dissolve the polymer. Subsequently, 3 parts by weight of “Blemmer” (registered trademark) G (glycidyl methacrylate, manufactured by NOF Corporation) was added and stirred at 70 ° C. for 30 minutes. Furthermore, 12 parts by weight of “Blenmer” GMR (methacrylic acid adduct of glycidyl methacrylate, manufactured by NOF Corporation), 5 parts by weight of “light ester” G201P (acrylic acid adduct of glycidyl methacrylate, manufactured by Kyoeisha Chemical Co., Ltd.), "Epoxy ester" 70PA (acrylic acid adduct of propylene glycol diglycidyl ether, manufactured by Kyoeisha Chemical Co., Ltd.), 6 parts by weight, "NK ester" A-200 (diacrylate of polyethylene glycol having an average molecular weight of 200, Shin-Nakamura Chemical Co., Ltd.) 5 parts by weight, “Irgacure” (registered trademark) 651 (benzyldimethyl ketal, manufactured by Ciba-Geigy) 0.1 parts by weight, “Irgacure” 184 (α-hydroxyketone, Ciba-Geigy ( Co., Ltd.) 1.5 parts by weight, “SuminolFastCyanine” "RenGconc." (acid dye, color index CI AcidGreen 25, manufactured by Sumitomo Chemical Co., Ltd.) 0.01 parts by weight, "Direct Sky Blue 6B" (produced by Hamamoto Dye Co., Ltd.) 0.01 parts by weight, ""Formaster" (antifoaming agent, Sannopco Co., Ltd.) 0.05 parts by weight, "Tinubin" (registered trademark) 327 (ultraviolet absorber, Ciba Geigy Co., Ltd.) 0.015 parts by weight, "TTP- 44 "(bis- {2- (2-ethoxyethoxycarbonyl) ethylthio} octylthiophosphine, Sakai Chemical Co., Ltd.) 0.2 parts by weight and" Q-1300 "(ammonium N-nitrosophenylhydroxylamine, Wako Pure Chemicals) Industrial Co., Ltd.) 0.005 part by weight was added and stirred for 30 minutes to obtain a coating liquid composition 1 of a fluid photosensitive resin layer (A1).

<Preparation of coating liquid composition 2 for photosensitive resin layer (A2)>
In a three-necked flask equipped with a stirring spatula and a condenser tube, 50 parts by weight of the water-soluble polyamide resin 2 obtained in Synthesis Example 3, 34 parts by weight of water, and 22 parts by weight of ethanol were added and stirred while stirring. The mixture was heated at 0 ° C. for 2 hours to dissolve the water-soluble polyamide resin 2. After cooling to 70 ° C., 1.5 parts by weight of “Blemmer” G (Glycidimethacrylate, manufactured by NOF Corporation) was added and stirred for 30 minutes. Furthermore, “Blemmer” GMR (glycerin dimethacrylate, manufactured by NOF Corporation) 8 parts by weight, HOA-MPE (2-acryloylethyl-2-hydroxyethylphthalic acid, manufactured by Kyoeisha Chemical Co., Ltd.) 24 parts by weight 5 parts by weight of PEG # 400 (polyethylene glycol, manufactured by Lion Corporation), 5 parts by weight of N, N, N ′, N′-tetra (2-hydroxy-3-methacryloyloxypropyl) -m-xylenediamine "NK ester" A-TMM-3 (tetramethylol methane triacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.) 4 parts by weight, "Irgacure" 651 (benzyldimethyl ketal, manufactured by Ciba-Geigy Co., Ltd.) 1.3 weights Part and hydroquinone monomethyl ether 0.01 parts by weight and stirred for 30 minutes, coating liquid composition 2 for photosensitive resin layer (A2) Obtained.

<Manufacture of photosensitive resin sheet 1>
Polyester adhesive (“Byron” (registered trademark) 30SS (copolymerized polyester, manufactured by Toyobo Co., Ltd.)) and 100 parts by weight of a 250 μm polyester film “Lumirror” (registered trademark) S10 (manufactured by Toray Industries, Inc.) "Coronate" (registered trademark) L (polyisocyanate, a solution obtained by mixing 3 parts by weight of Nippon Polyurethane Industry Co., Ltd.) was dried and then coated with a bar coater to a thickness of 20 µm and dried at 90 ° C for 10 minutes. To obtain a support having an adhesive layer.

  The coating liquid composition 1 for the photosensitive resin layer (A1) is cast on the support, dried in an oven at 60 ° C. for 5 hours, and the photosensitive resin sheet 1 having a thickness of 950 μm including the support. Got. The thickness of the photosensitive resin sheet 1 is such that a spacer having a predetermined thickness is placed on the support, and the coating liquid composition 1 for the photosensitive resin layer (A1) protruding from the spacer is placed on a horizontal metal scale. Adjusted by scraping.

<Manufacture of photosensitive resin sheet 2>
A support having an adhesive layer was obtained by the method described in the production of the photosensitive resin sheet 1. The coating liquid composition 2 for the photosensitive resin layer (A2) is cast on the support, dried in an oven at 60 ° C. for 2 hours, and a photosensitive resin sheet having a thickness of 950 μm including the support. 2 was obtained. The thickness of the photosensitive resin sheet 2 is such that a spacer having a predetermined thickness is placed on the support, and the coating liquid composition 2 for the photosensitive resin layer (A2) protruding from the spacer is placed on a horizontal metal scale. Adjusted by scraping.

<Preparation of coating liquid composition 1 for peeling auxiliary layer (E1)>
11 parts by weight of “GOHSENOL” AL-06 (polyvinyl alcohol having a saponification degree of 91% to 94%, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 55 parts by weight of water, 14 parts by weight of methanol, 10 parts by weight of n-propanol and n- 10 parts by weight of butanol was stirred and dissolved at 80 ° C. to obtain a coating liquid composition 1 for the peeling assist layer (E1).

<Preparation of coating liquid composition 2 for peeling auxiliary layer (E2)>
Partially saponified polyvinyl alcohol “GOHSENOL” KL-05 (saponification degree measured by the method shown in JIS K6726 (1994) 78.5 mol% to 82.0 mol%, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 11 parts by weight 55 parts by weight, 14 parts by weight of methanol, 10 parts by weight of n-propanol and 10 parts by weight of n-butanol were stirred and dissolved at 80 ° C. to obtain a coating liquid composition 2 for the peeling assist layer (E2).

<Preparation of coating liquid composition 1 for thermal mask layer (B1)>
“MA100” (carbon black, primary particle diameter (arithmetic average diameter obtained by observing carbon black particles with an electron microscope) 24 nm, manufactured by Mitsubishi Chemical Corporation) 23 parts by weight, “Dianar” (registered trademark) BR -95 (alcohol-insoluble acrylic resin, manufactured by Mitsubishi Rayon Co., Ltd.) 15 parts by weight, plasticizer ATBC (tributyl acetyl citrate, manufactured by J Plus Co., Ltd.) 6 parts by weight, and methyl isobutyl ketone 30 parts by weight The resulting mixture was kneaded and dispersed using a three-roll mill to prepare a carbon black dispersion 1. In dispersion 1, 20 parts by weight of “Araldite” 6071 (epoxy resin, manufactured by Asahi Ciba), 27 parts by weight of “Uban” (registered trademark) 2061 (melamine resin, manufactured by Mitsui Chemicals), “light ester” 0.7 parts by weight of P-1M (phosphoric acid monomer, manufactured by Kyoeisha Chemical Co., Ltd.) and 140 parts by weight of methyl isobutyl ketone were added and stirred at room temperature for 30 minutes. Then, the dispersion liquid further added with methyl isobutyl ketone so that the solid content concentration was 33% by weight was heat-treated at 50 ° C. for 6 days to obtain a coating liquid composition 1 for the thermal mask layer (B1). . When the particle size distribution of the pigment was measured by the above method, the ratio of the particle size of 240 nm or more was 35%, and the particle size at the maximum value of the particle size distribution was 243 nm.

<Preparation of coating liquid composition 2 for thermal mask layer (B2)>
“MA100” (carbon black, manufactured by Mitsubishi Chemical Corporation) 23 parts by weight, “Dianal” BR-95 (alcohol-insoluble acrylic resin, manufactured by Mitsubishi Rayon Co., Ltd.) 15 parts by weight, plasticizer ATBC (acetyl citrate) A carbon black dispersion 2 was prepared by kneading and dispersing a mixture of 1 part by weight of tributyl (manufactured by J. Plus) and 30 parts by weight of methyl isobutyl ketone using a three-roll mill. In dispersion 2, 1 part by weight of AER6071 (epoxy resin, manufactured by Asahi Kasei Chemicals), 1 part by weight of “Uban” 20SE60 (melamine resin, manufactured by Mitsui Chemicals), “light ester” P-1M (phosphoric acid monomer) 0.05 parts by weight of Kyoeisha Chemical Co., Ltd.) and 100 parts by weight of methyl isobutyl ketone were added and stirred at room temperature for 30 minutes. Furthermore, it heat-processed at 50 degreeC for 6 days, and obtained the coating liquid composition 2 for thermal mask layers (B2). When the particle size distribution of the pigment was measured by the above method, the ratio of the particle size of 240 nm or more was 35%, and the particle size at the maximum value of the particle size distribution was 243 nm.

<Preparation of coating liquid composition 3 for thermal mask layer (B3)>
The coating liquid composition 3 for the thermal mask layer (B3) is obtained in the same manner as the coating liquid composition 1 for the thermal mask layer (B1) except that the heat treatment of the dispersion is performed at 50 ° C. for 2 days. It was. When the pigment particle size distribution was measured by the above method, the ratio of the particle size of 240 nm or more was 22%, and the particle size at the maximum value of the particle size distribution was 145 nm.

<Preparation of coating liquid composition 4 for thermal mask layer (B4)>
The coating liquid composition 4 for the thermal mask layer (B4) is obtained in the same manner as the coating liquid composition 2 for the thermal mask layer (B2) except that the heat treatment of the dispersion is performed at 50 ° C. for 2 days. It was. When the pigment particle size distribution was measured, the ratio of the particle size of 240 nm or more was 22%, and the particle size at the maximum value of the particle size distribution was 145 nm.

<Preparation of coating liquid composition 5 for thermal mask layer (B5)>
A coating liquid composition 5 for the thermal mask layer (B5) was obtained in the same manner as the coating liquid composition 1 for the thermal mask layer (B1) except that the dispersion was not subjected to heat treatment. When the pigment particle size distribution was measured, the ratio of the particle size of 240 nm or more was 4%, and the particle size at the maximum value of the particle size distribution was 122 nm.

<Preparation of coating liquid composition 6 for thermal mask layer (B6)>
A coating liquid composition 6 for the thermal mask layer (B6) was obtained in the same manner as the coating liquid composition 2 for the thermal mask layer (B2) except that the dispersion was not heat-treated. When the pigment particle size distribution was measured, the ratio of the particle size of 240 nm or more was 4%, and the particle size at the maximum value of the particle size distribution was 122 nm.

<Preparation of coating liquid composition 1 for intermediate layer (C1)>
5 parts by weight of the modified polyvinyl alcohol 1 obtained in Synthesis Example 1 is dissolved in 47.5 parts by weight of water and 47.5 parts by weight of an alcohol mixture having 1 to 4 carbon atoms, and a coating solution for the intermediate layer (C1). Composition 1 was obtained.

<Preparation of coating liquid composition 2 for intermediate layer (C2)>
“Gosenol” L-17 (polyvinyl alcohol having a saponification degree of about 50%, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 3.2 parts by weight and 11.9 parts by weight of the water-soluble polyamide resin 2 obtained in Synthesis Example 3 were mixed with water. It was dissolved in 38.0 parts by weight and 46.9 parts by weight of an alcohol mixture having 1 to 4 carbon atoms to obtain a coating liquid composition 2 for the intermediate layer (C2).

<Manufacture of thermal mask element 1>
On the polyester film “Lumirror” S10 (manufactured by Toray Industries, Inc.) having a thickness of 100 μm, the coating liquid composition 1 for the peeling auxiliary layer (E1) is dried to a thickness of 0.25 μm using a bar coater. And dried at 100 ° C. for 25 seconds to obtain a laminate of the peeling assist layer (E1) / cover film (D). The coating liquid composition 1 for the heat-sensitive mask layer (B1) is applied to the peeling auxiliary layer (E1) side of the laminate thus obtained so that the dry film thickness becomes 1.0 μm using a bar coater. And dried at 140 ° C. for 30 seconds to obtain a laminate of a thermal mask layer (B1) / peeling auxiliary layer (E1) / cover film (D). On the heat-sensitive mask layer (B1) side of the laminate thus obtained, the coating liquid composition 1 for the intermediate layer (C1) was applied using a bar coater so that the dry film thickness was 1 μm. And dried at 180 ° C. for 30 seconds to obtain a thermal mask element 1 which is a laminate of intermediate layer (C1) / thermal mask layer (B1) / peeling auxiliary layer (E1) / cover film (D). When the optical density of the thermal mask layer (B1) of this thermal mask element 1 was measured, OD (UV) = 2.8, OD (K) = 2.0, and OD (UV) / OD (K) = 1.4. When the pigment particle size distribution was measured by the above method, the ratio of the particle size of 240 nm or more was 33%, and the particle size at the maximum value of the particle size distribution was 243 nm. That is, it was found that the pigment particle size distribution in the thermal mask layer is equivalent to the pigment particle size distribution in the coating liquid composition for the thermal mask layer.

<Manufacture of thermal mask element 2>
In place of the coating liquid composition 1 for the thermal mask layer (B1), the coating liquid composition 1 for the intermediate layer (C1), and the coating liquid composition 1 for the peeling auxiliary layer (E1), respectively, a thermal mask. Thermal mask element 1 except that the coating liquid composition 2 for the layer (B2), the coating liquid composition 2 for the intermediate layer (C2), and the coating liquid composition 2 for the peeling auxiliary layer (E2) were used. In the same manner as above, a thermal mask element 2 which is a laminate of the intermediate layer (C2) / thermal mask layer (B2) / peeling auxiliary layer (E2) / cover film (D) was obtained. When the optical density of the thermal mask layer (B2) of the thermal mask element 2 was measured, OD (UV) = 2.8, OD (K) = 2.0, and OD (UV) / OD (K) = 1.4. From the pigment particle size distribution in the coating liquid composition for the thermal mask layer, the pigment particle size distribution in the thermal mask layer is such that the ratio of the particle size of 240 nm or more is 35%, and the particle size at the maximum value of the particle size distribution is 243 nm. I can guess.

<Manufacture of thermal mask element 3>
The intermediate layer (C1) is the same as the thermal mask element 1 except that the coating liquid composition 3 for the thermal mask layer (B3) is used instead of the coating liquid composition 1 for the thermal mask layer (B1). ) / Thermal mask layer (B3) / peeling auxiliary layer (E1) / cover film (D) was obtained. When the optical density of the thermal mask layer (B3) of the thermal mask element 3 was measured, OD (UV) = 2.4, OD (K) = 2.0, and OD (UV) / OD (K) = 1.2. From the pigment particle size distribution in the coating liquid composition for the heat-sensitive mask layer, the pigment particle size distribution in the heat-sensitive mask layer is 22% of the ratio of the particle size of 240 nm or more, and the particle size at the maximum value of the particle size distribution is 145 nm. I can guess.

<Manufacture of thermal mask element 4>
The intermediate layer (C2) is the same as the thermal mask element 2 except that the coating liquid composition 4 for the thermal mask layer (B4) is used instead of the coating liquid composition 2 for the thermal mask layer (B2). ) / Thermal mask layer (B4) / peeling auxiliary layer (E2) / cover film (D) was obtained. When the optical density of the thermal mask layer (B4) of this thermal mask element 4 was measured, OD (UV) = 2.4, OD (K) = 2.0, and OD (UV) / OD (K) = 1.2. From the pigment particle size distribution in the coating liquid composition for the heat-sensitive mask layer, the pigment particle size distribution in the heat-sensitive mask layer is 22% of the ratio of the particle size of 240 nm or more, and the particle size at the maximum value of the particle size distribution is 145 nm. I can guess.

<Manufacture of thermal mask element 5>
The intermediate layer (C1) is the same as the thermal mask element 1 except that the coating liquid composition 5 for the thermal mask layer (B5) is used instead of the coating liquid composition 1 for the thermal mask layer (B1). ) / Thermal mask layer (B5) / peeling auxiliary layer (E1) / cover film (D) was obtained. When the optical density of the thermal mask layer (B5) of the thermal mask element 5 was measured, OD (UV) = 2.2, OD (K) = 2.0, and OD (UV) / OD (K) = 1.1. From the pigment particle size distribution in the coating liquid composition for the thermal mask layer, the pigment particle size distribution in the thermal mask layer is such that the ratio of the particle size of 240 nm or more is 4%, and the particle size at the maximum value of the particle size distribution is 122 nm. I can guess.

<Manufacture of thermal mask element 6>
The intermediate layer (C2) is the same as the thermal mask element 2 except that the coating liquid composition 6 for the thermal mask layer (B6) is used instead of the coating liquid composition 2 for the thermal mask layer (B2). ) / Thermal mask layer (B6) / peeling auxiliary layer (E2) / cover film (D) was obtained. When the optical density of the thermal mask layer (B6) of the thermal mask element 6 was measured, OD (UV) = 2.2, OD (K) = 2.0, and OD (UV) / OD (K) = 1.1. From the pigment particle size distribution in the coating liquid composition for the thermal mask layer, the pigment particle size distribution in the thermal mask layer is such that the ratio of the particle size of 240 nm or more is 4%, and the particle size at the maximum value of the particle size distribution is 122 nm. I can guess.

<Manufacture of thermal mask element 7>
A thermal mask element 7 was obtained in the same manner as the thermal mask element 5 except that the dry thickness of the thermal mask layer was 1.8 μm. When the optical density of the thermal mask layer (B5 ′) of the thermal mask element 7 was measured, OD (UV) = 3.9 and OD (K) = 3.5, and OD (UV) / OD (K). = 1.1. From the pigment particle size distribution in the coating liquid composition for the thermal mask layer, the pigment particle size distribution in the thermal mask layer is such that the ratio of the particle size of 240 nm or more is 4%, and the particle size at the maximum value of the particle size distribution is 122 nm. I can guess.

<Manufacture of thermal mask element 8>
A thermal mask element 8 was obtained in the same manner as the thermal mask element 6 except that the dry thickness of the thermal mask layer was 1.8 μm. When the optical density of the heat-sensitive mask layer (B6 ′) of the heat-sensitive mask element 8 was measured, OD (UV) = 3.9, OD (K) = 3.5, and OD (UV) / OD (K) = 1.1. From the pigment particle size distribution in the coating liquid composition for the heat-sensitive mask layer, it can be estimated that the pigment particle size distribution has a ratio of the particle size of 240 nm or more of 4%, and the particle size at the maximum value of the particle size distribution is 122 nm.

  Table 1 shows the composition of the thermal mask element, the heat treatment conditions for the coating liquid composition for the thermal mask layer, the pigment particle size distribution in the coating liquid composition for the thermal mask layer, and the optical density of the thermal mask layer.

Example 1
The coating liquid composition 1 for the photosensitive resin layer (A1) is spread on the photosensitive resin layer (A1) of the photosensitive resin sheet 1, and the intermediate layer (C1) is coated with the thermal mask element 1 thereon. Cover the photosensitive resin layer (A1) on which the working liquid composition 1 is spread and laminate it with a calender roll heated to 80 ° C., and support / photosensitive resin layer (A1) / intermediate layer (C1) ) / Thermosensitive mask layer (B1) / peeling auxiliary layer (E1) / cover film (D) were laminated in this order to obtain a photosensitive resin printing plate precursor 1. The clearance of the calendar roll was adjusted so that the thickness of the laminate after peeling the cover film (D) from the original plate 1 was 950 μm. The developed coating liquid composition 1 is allowed to stand for 1 week after laminating, whereby the remaining solvent is naturally dried to form an additional photosensitive resin layer (A1).

  When the drawing sensitivity was evaluated by the above-described method using the photosensitive resin printing plate precursor 1, the heat-sensitive mask layer (B1) in the solid portion was substantially ablated, and the drawing defect (drawing residue) due to the remaining heat-sensitive mask layer was It did not occur. Further, since the heat-sensitive mask layer (B1) was cross-linked, it was resistant to trauma and easy to handle such as mounting on a plate setter.

Subsequently, from the image mask (B1 ′) side formed on the thermal mask layer (B1), the entire surface was exposed with an ultrahigh pressure mercury lamp (manufactured by Oak Co., Ltd.) having a light source in the ultraviolet region (maximum wavelength: 365 nm, exposure amount). : 1000 mJ / cm ² ). Subsequently, development was carried out with tap water at 25 ° C. for 1.5 minutes using a brush type developing machine FTW430II (manufactured by Toray Industries, Inc.) equipped with a brush made of PBT (polybutylene terephthalate). The image mask (B1 ′) and the portion of the photosensitive resin layer (A1) that is blocked by the image mask and not exposed to ultraviolet rays are selectively developed to leave a relief cured by exposure, and the image mask (B1 ′) is exposed. Negative relief was faithfully reproduced.

Further, the relief thus obtained was dried at 60 ° C. for 10 minutes, and then the entire surface was exposed (exposure amount: 1000 mJ / cm ² ) with an ultrahigh pressure mercury lamp (manufactured by Oak Co., Ltd.) having a light source in the ultraviolet region. 1 was obtained. When the OD (UV) / OD (K) of the obtained printing plate 1 was measured by the above method, it was 1.4. When the light shielding property was evaluated by the above method, no exposure defect occurred.

(Example 2)
The photosensitive resin printing plate precursor 2 and the printing plate 2 were prepared in the same manner as in Example 1 except that the photosensitive resin sheet 2 was used instead of the photosensitive resin sheet 1 and the thermal mask element 2 was used instead of the thermal mask element 1. Got. Table 2 shows the results of evaluating the optical density, drawing sensitivity, and light shielding properties of the thermal mask layer.

(Example 3)
Photosensitive resin printing plate precursor 3 and printing plate 3 were obtained in the same manner as in Example 1 except that thermal mask element 3 was used instead of thermal mask element 1. Table 2 shows the results of evaluating the optical density, drawing sensitivity, and light shielding properties of the thermal mask layer.

Example 4
A photosensitive resin printing plate precursor 4 and a printing plate 4 were obtained in the same manner as in Example 2 except that the thermal mask element 4 was used instead of the thermal mask element 2. Table 2 shows the results of evaluating the optical density, drawing sensitivity, and light shielding properties of the thermal mask layer.

(Comparative Example 1)
A photosensitive resin printing plate precursor 5 and a printing plate 5 were obtained in the same manner as in Example 1 except that the thermal mask element 5 was used instead of the thermal mask element 1. Table 2 shows the results of evaluating the optical density, drawing sensitivity, and light shielding properties of the thermal mask layer.

(Comparative Example 2)
A photosensitive resin printing plate precursor 6 and a printing plate 6 were obtained in the same manner as in Example 2 except that the thermal mask element 6 was used instead of the thermal mask element 2. Table 2 shows the results of evaluating the optical density, drawing sensitivity, and light shielding properties of the thermal mask layer.

(Comparative Example 3)
A photosensitive resin printing plate precursor 7 and a printing plate 7 were obtained in the same manner as in Example 1 except that the thermal mask element 7 was used instead of the thermal mask element 1. Table 2 shows the results of evaluating the optical density, drawing sensitivity, and light shielding properties of the thermal mask layer.

(Comparative Example 4)
A photosensitive resin printing plate precursor 8 and a printing plate 8 were obtained in the same manner as in Example 2 except that the thermal mask element 8 was used instead of the thermal mask element 2. Table 2 shows the results of evaluating the optical density, drawing sensitivity, and light shielding properties of the thermal mask layer.

(Comparative Example 5)
Table 2 shows the evaluation results of the optical density, drawing sensitivity, and light-shielding property of the thermal mask layer of “Nyloprint” (registered trademark) WF95HD manufactured by Flint Group.

(Comparative Example 10)
Table 2 shows the evaluation results of the optical density, drawing sensitivity, and light-shielding property of the thermal mask layer of “Printight” (registered trademark) QF95JC manufactured by Toyobo Co., Ltd.

Claims (4)

A photosensitive resin printing plate precursor having, in this order, at least a photosensitive resin layer (A) and a heat-sensitive mask layer (B) containing a pigment on a support, the heat-sensitive mask layer (B) containing the pigment Satisfying OD (UV) / OD (K) ≧ 1.2. 2. The photosensitive resin printing plate precursor according to claim 1, wherein the pigment particle size distribution in the heat-sensitive mask layer (B) is 20% or more of a pigment having a particle size of 240 nm or more. A coating liquid composition for a thermal mask layer comprising a step of forming at least a photosensitive resin layer (A) on a support and a pigment having a particle size distribution in which a pigment having a particle size of 240 nm or more is 20% or more. The method for producing a photosensitive resin printing plate precursor according to claim 1, further comprising a step of forming a heat-sensitive mask layer (B). 4. The method for producing a photosensitive resin printing plate precursor according to claim 3, wherein the coating liquid composition for the heat-sensitive mask layer is heat-treated at a temperature of 40 [deg.] C. or more for 1 hour or more.