Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M1/00—Inking and printing with a printer's forme
  • B41M1/02—Letterpress printing, e.g. book printing
  • B41M1/04—Flexographic printing
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/004—Photosensitive materials
  • G03F7/09—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers
  • G03F7/11—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers having cover layers or intermediate layers, e.g. subbing layers
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/004—Photosensitive materials
  • G03F7/09—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers
  • G03F7/095—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers having more than one photosensitive layer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
  • B41N1/00—Printing plates or foils; Materials therefor
  • B41N1/12—Printing plates or foils; Materials therefor non-metallic other than stone, e.g. printing plates or foils comprising inorganic materials in an organic matrix
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/20—Exposure; Apparatus therefor
  • G03F7/2002—Exposure; Apparatus therefor with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image
  • G03F7/2014—Contact or film exposure of light sensitive plates such as lithographic plates or circuit boards, e.g. in a vacuum frame
  • G03F7/2016—Contact mask being integral part of the photosensitive element and subject to destructive removal during post-exposure processing
  • G03F7/202—Masking pattern being obtained by thermal means, e.g. laser ablation
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/20—Exposure; Apparatus therefor
  • G03F7/24—Curved surfaces

Definitions

• the present invention relates to a flexographic printing original plate in which the pinholes of the thermal mask layer are reduced and reduced.
• Flexographic printing is a printing method in which ink is placed on the convex parts of the plate material and the plate material is pressed against the base material to transfer the ink from the plate material to the base material. Since the plate material used for flexographic printing is relatively flexible and can follow various shapes, it is possible to print on a wide range of base materials. Examples of the base material include packaging films, label papers, beverage cartons, paper containers, envelopes, cardboards, etc. Among them, flexographic printing is exclusively used for the base material having a rough surface. In addition, flexographic printing is a printing method that is highly environmentally adaptable because it can use water-based or alcoholic inks with low VOC emissions. Due to these advantages such as substrate adaptability and environmental adaptability, the transition from gravure printing and offset printing to flexographic printing is progressing.
• microcell is a device in which a microcell pattern is imaged on a heat-sensitive mask layer and then reproduced on a printing plate through exposure and development steps.
• it is important to faithfully reproduce the imaging image of the heat-sensitive mask layer on the printing plate. Therefore, the inhibition of oxygen polymerization of the photosensitive resin layer is suppressed, and the imaging image of the heat-sensitive mask layer is faithfully reproduced on the printing plate. Efforts are being made to reproduce it.
• the current situation is that there is a strong demand for flexographic original plates that can reduce and reduce the pinholes in the thermal mask layer by a simple method.
• the present invention has been devised in view of the current state of the prior art, and provides a flexographic printing original plate in which the pinholes of the thermal mask layer are reduced and reduced by a simple process, and has drawbacks due to pinholes as compared with the flexographic printing original plate.
• the purpose is to provide a flexographic printing plate that is almost nonexistent.
• the present inventor has found that the heat-sensitive mask layer of the cover film is at least in the flexographic printing original plate in which the support, the photosensitive resin layer, the heat-sensitive mask layer, and the cover film are sequentially laminated.
• a protective layer formed from a polymer compound that is configured so that the surface energy and surface roughness (Ra) of the contacting surface are within a specific range, and is further dispersible in a developing solution between the photosensitive resin layer and the thermal mask layer. It has been found that a flexographic printing plate in which the pinholes of the thermal mask layer are small and reduced can be easily obtained, and as a result, a flexographic printing plate having almost no defects due to pinholes can be provided.
• the present invention has the following configurations (1) to (5).
• a flexographic original plate in which at least a support (A), a photosensitive resin layer (B), a heat-sensitive mask layer (C), and a cover film (D) are sequentially laminated, and the heat-sensitive of the cover film (D).
• the surface energy of the surface in contact with the mask layer (C) is 25.0 to 40.0 mN / m, the surface roughness (Ra) is 0.01 to 0.2 ⁇ m, and the photosensitive resin layer (B).
• a protective layer (E) formed of a polymer compound dispersible in a developing solution is provided, which is a flexographic printing original plate.
• the flexographic printing original plate of the present invention is configured so that the surface energy and surface roughness (Ra) of the surface of the cover film in contact with the heat-sensitive mask layer are within a specific range, and further between the photosensitive resin layer and the heat-sensitive mask layer. Since a protective layer formed of a dispersible polymer compound is provided in the developing solution, a flexographic printing master plate in which the pinholes of the thermal mask layer are small and reduced can be easily obtained, and as a result, the drawbacks due to pinholes are eliminated. Almost no flexographic printing plate can be provided.
• the flexographic printing original plate of the present invention is a flexographic printing original plate in which at least a support (A), a photosensitive resin layer (B), a thermal mask layer (C), and a cover film (D) are sequentially laminated, and is a cover film.
• the surface energy of the surface in contact with the heat-sensitive mask layer (C) of (D) is 25.0 to 40.0 mN / m, the surface roughness (Ra) is 0.01 to 0.2 ⁇ m, and the photosensitive layer is photosensitive.
• a protective layer (E) formed of a polymer compound dispersible in a developing solution is provided between the sex resin layer (B) and the thermal mask layer (C).
• the surface energy and surface roughness of the surface of the cover film (D) in contact with the heat-sensitive mask layer (C) can be controlled within a specific range, and the surface of the heat-sensitive mask layer (C) in contact with the cover film (D) can be controlled.
• the specific protective layer (E) on the opposite surface, it is possible to prevent pinholes from being generated in the printing master during coating or processing of the thermal mask layer (C).
• the support (A) used for the flexographic original plate is preferably a material having flexibility but excellent dimensional stability, for example, a metal support such as steel, aluminum, copper, nickel, polyethylene terephthalate film, etc.
• a thermoplastic resin support such as a polyethylene naphthalate film, a polybutylene terephthalate film, or a polycarbonate film can be used. Among these, a polyethylene terephthalate film having excellent dimensional stability and sufficiently high viscoelasticity is particularly preferable.
• the thickness of the support is preferably 50 to 350 ⁇ m, preferably 100 to 250 ⁇ m, from the viewpoint of mechanical properties, shape stabilization, handleability during printing plate making, and the like.
• an adhesive layer may be provided between the support (A) and the photosensitive resin layer (B) in order to improve the adhesiveness.
• the photosensitive resin composition forming the photosensitive resin layer (B) used in the flexo printing original plate is not particularly limited, but is generally (a) a polymer obtained by polymerizing a conjugated dye, and (b) ethylenic. Unsaturated compounds and (c) photopolymerization initiators can be included, and optionally plastics, hydrophilic compounds, UV absorbers, surface tension modifiers, thermal polymerization inhibitors, dyes, pigments, fragrances, or oxidations. Additives such as inhibitors can be included.
• a conventionally known synthetic polymer compound used for a printing original plate can be used. Specific examples thereof include a polymer obtained by polymerizing a conjugated diene-based hydrocarbon, or a copolymer obtained by copolymerizing a conjugated diene-based hydrocarbon and a monoolefin-based unsaturated compound.
• butadiene polymer isoprene polymer, chloroprene copolymer, styrene-butadiene copolymer, styrene-butadiene-styrene copolymer, styrene-isoprene copolymer, styrene-isoprene-styrene copolymer, styrene-chloroprene Polymer, acrylonitrile-butadiene copolymer, acrylonitrile-isoprene copolymer, methyl methacrylate-butadiene copolymer, methyl methacrylate-isoprene copolymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-isoprene-styrene Examples thereof include copolymers.
• a butadiene polymer is preferably used from the viewpoint of the characteristics of a flexographic printing plate, that is, the impact resilience of the plate surface, the physical properties of strong elongation, the hardness of the resin plate, the morphological stability when unexposed, or the availability.
• These polymers may be used alone or in combination of two or more.
• the ratio of the component (a) in the photosensitive resin composition forming the photosensitive resin layer (B) is preferably in the range of 40 to 70% by mass.
• ethylenically unsaturated compound a conventionally known compound used for a printing original plate can be used.
• the ratio of the component (b) in the photosensitive resin composition forming the photosensitive resin layer (B) is preferably in the range of 10 to 50% by mass.
• (C) As the photopolymerization initiator, a conventionally known one used for a printing original plate can be used. Examples thereof include benzophenones, benzoins, acetophenones, benzyls, benzoin alkyl ethers, benzylalkyl ketals, anthraquinones, thioxanthones and the like.
• the ratio of the component (c) in the photosensitive resin composition forming the photosensitive resin layer (B) is preferably in the range of 1 to 10% by mass.
• the heat-sensitive mask layer (C) used for the flexo printing original plate the one used for the printing original plate can be used.
• it has a function of absorbing an infrared laser and converting it into heat and a function of blocking ultraviolet light.
• It is preferably composed of carbon black, which is a material to be contained, a dispersion binder thereof, and a binder polymer capable of forming a film.
• the dispersion binder and the binder polymer capable of forming a film can be used in combination with one material.
• a pigment dispersant, a filler, a surfactant, a coating aid, or the like can be contained within a range that does not impair the effects of the present invention.
• the heat-sensitive mask layer (C) used in the flexographic printing original plate of the present invention is preferably water-developable.
• the heat-sensitive mask layer (C) include a heat-sensitive mask layer (Patent No. 4250110) in which a polar group-containing polyamide and a butyral resin are combined, a polymer having the same structure as the polymer in the photosensitive resin layer, and an acrylic resin. (Patent No. 5710961), a heat-sensitive mask layer containing an anionic polymer and a polymer having an ester bond on the side chain and having a saponification degree of 0% or more and 90% or less (Patent No. 5525704). Examples thereof include a heat-sensitive mask layer (Patent No. 6358523) in which a methoxymethylated polyamide resin and a water-soluble polyamide resin containing a basic nitrogen atom in the molecule are combined.
• the cover film (D) used in the flexographic printing original plate of the present invention is preferably a material having flexibility but excellent dimensional stability, and is thermoplastic such as polyethylene terephthalate film, polyethylene naphthalate film, and polybutylene terephthalate film.
• a resin support can be used.
• a polyethylene terephthalate film having excellent dimensional stability and sufficiently high viscoelasticity is particularly preferable.
• the thickness of the cover film (D) is preferably 50 to 350 ⁇ m, more preferably 100 to 250 ⁇ m, from the viewpoint of mechanical properties, shape stability, handleability during printing plate making, and the like.
• the surface energy of the surface of the cover film (D) in contact with the heat-sensitive mask layer (C) is 25.0 to 40.0 mN / m, and the surface roughness (Ra) is 0.01. It is characterized in that it is configured to be ⁇ 0.2 ⁇ m.
• the surface energy is 25.0 to 39.0 mN / m, and the surface roughness (Ra) is 0.02 to 0.18 ⁇ m.
• the surface energy of the cover film (D) is less than the above range, the wettability of the liquid when the heat-sensitive mask layer (C) is applied on the cover film (D) cannot be ensured, and pinholes are sufficiently suppressed. Can't. Further, the adhesive force between the heat-sensitive mask layer (C) and the cover film (D) is not sufficient, and it is not possible to prevent the printing original plate from falling off in the manufacturing process. Normally, in the manufacturing process of the printing original plate, the heat-sensitive mask layer (C) surface of the cover film (D) provided with the heat-sensitive mask layer (C) comes into contact with a plurality of rolls, so that the heat-sensitive mask layer (C) comes into contact with the rolls. It may cause scratches and pinholes.
• the cover film (D) can be appropriately peeled from the printing original plate at the time of plate making. If it exceeds the above range, the adhesive force between the heat-sensitive mask layer (C) and the cover film (D) is too strong, and a part of the heat-sensitive mask layer (C) is on the cover film (D) side when the cover film (D) is peeled off. Pinholes may occur by shifting to.
• Surface energy is the energy that molecules existing on the surface have more than the molecules existing inside.
• the magnitude of surface energy is mainly determined by the magnitude of intermolecular force. Therefore, the surface energy can be adjusted by using materials having different intermolecular forces. Examples of materials having low intermolecular force and low surface energy include resins having long-chain alkyl groups, silicone resins, and fluororesins. On the other hand, examples of the material having a high intermolecular force and a large surface energy include a polyamide resin and a polyvinyl alcohol resin.
• the surface energy of the cover film (D) can be controlled by applying a suitable surface energy adjusting agent to the surface of the cover film.
• a suitable surface energy adjusting agent those generally used as a release agent for a film can be used as long as the surface energy in a target range can be achieved.
• acrylic resin, alkyd resin, polyester resin, urethane resin, polyamide resin, amino resin, epoxy resin, silicone resin, fluororesin, various waxes, aliphatic olefins and the like can be used. From these, a suitable one may be appropriately selected according to the above-mentioned index according to the target surface energy level. These can be used alone or in combination of two or more types. Of these, acrylic resin is preferable.
• a long-chain alkyl (preferably having 12 to 22 carbon atoms) acrylate copolymer alkyl resin is preferable from the viewpoint that the effect of adjusting the surface energy is easily exhibited.
• a long-chain alkyl acrylate copolymerized alkyl resin a commercially available one may be used, and for example, Peroyl (manufactured by Lion Corporation) is a preferable example.
• the surface energy of the cover film (D) is measured according to the determination method using a wetting reagent (plastic-film and sheet-wetting tension test method) described in JIS K6768.
• the surface roughness (Ra) of the cover film (D) is less than the above range, the cover film is too smooth and the film loses its slipperiness, and pinholes are likely to occur during roll contact in the processing process.
• the surface roughness (Ra) of the cover film (D) exceeds the above range, the liquid does not uniformly wet and spread during the coating of the heat-sensitive mask layer (C), and pinholes are likely to occur.
• the pressure of the convex portion increases at the time of roll contact in the processing process, the convex portion is likely to be scratched.
• the surface roughness of the cover film (D) can be controlled by using cover films having different surface roughness or by applying fine particles to the surface of the cover film (D) to adjust the surface roughness. ..
• Examples of a method for producing cover films having different surface roughness include a method of treating a PET film with an alkaline agent. In this case, the surface roughness can be controlled by adjusting the treatment time of the alkaline agent and the concentration of the alkaline agent.
• the method of coating the fine particles for example, Epostal (thermosetting resin spherical fine particles made from melamine resin and benzoguanamine resin) sold by Nippon Shokubai Co., Ltd. can be used as the fine particles.
• the surface roughness (Ra) of the cover film (D) is measured by a non-contact method instead of a contact method. This is because the cover film, which is the object of measuring the surface roughness (Ra) in the present invention, is relatively soft. Therefore, in the contact method, the cover film is deformed by the contact with the stylus of the measuring instrument, and the cover film is accurately deformed. This is because the surface roughness (Ra) cannot be measured.
• the confocal method using a confocal laser microscope was adopted.
• the protective layer (E) used in the flexographic printing original plate of the present invention is provided directly on the surface of the thermal mask layer (C) opposite to the surface in contact with the cover film (D), and is applied to the printing original plate. After the processing of, it is arranged between the heat-sensitive mask layer (C) and the photosensitive resin layer (B). Further, the protective layer (E) of the present invention is formed of a polymer compound dispersible in a developing solution and is removed during the developing process. Since the heat-sensitive mask layer (C) contains a large amount of particles such as carbon black due to its characteristics, the film is very brittle. Therefore, in the present invention, by providing the protective layer (E), the heat-sensitive mask layer (C) is protected from the force generated at the time of roll contact in the processing process, and the heat-sensitive mask layer (C) is damaged (pinhole). To prevent.
• the surface of the heat-sensitive mask layer (C) in contact with the cover film (D) is used. Apply and dry a solution in which the components of the protective layer (E) are dissolved on the opposite surface to form the protective layer (E), or contact the cover film (D) of the heat-sensitive mask layer (C). Examples thereof include a method of laminating a protective layer (E) formed in advance on a surface opposite to the surface. Of these, the former method of applying and drying to form the protective layer (E) is convenient and preferable.
• the film thickness of the protective layer (E) is preferably 0.2 ⁇ m to 15 ⁇ m. If it is less than 0.2 ⁇ m, damage (pinhole) of the thermal mask layer (C) may not be sufficiently prevented, and if it exceeds 15 ⁇ m, it may be difficult to remove it in the developing process.
• the material of the protective layer (E) a conventionally known material can be used as long as it is a polymer compound that can be dispersed in a developing solution.
• a polymer compound that can be dispersed in a developing solution.
• polyurethane, polyamide, polyester, polybutadiene, polyacrylonitrile, polystyrene, polybutadiene styrene, acrylic polymer, polyvinyl alcohol, partially saponified vinyl acetate polymer, alkyl cellulose, cellulosic polymer, and various modified products of these polymer compounds can be used.
• These polymers are not limited to one type of use, and two or more types of polymers can be used in combination.
• the method for producing the flexographic printing master plate of the present invention is not particularly limited, but is produced, for example, as follows. First, a component such as a binder other than carbon black in the heat-sensitive mask layer (C) is dissolved in an appropriate solvent, and carbon black is dispersed therein to prepare a dispersion liquid. Next, such a dispersion is applied on the cover film (D) to evaporate the solvent. Then, the protective layer (E) component is overcoated to prepare one laminate. Further, separately from this, a photosensitive resin layer (B) is formed on the support (A) by coating to prepare the other laminated body. The two laminates thus obtained are laminated under pressure and / or heating so that the photosensitive resin layer (B) is adjacent to the protective layer (E). The cover film (D) functions as a protective film on the surface of the original printing plate after completion.
• a component such as a binder other than carbon black in the heat-sensitive mask layer (C) is dissolved in an appropriate solvent, and carbon black is dispersed there
• a method of manufacturing a flexographic printing plate from the flexographic printing original plate manufactured as described above first, the cover film (D) is removed from the flexographic printing original plate. Then, the heat-sensitive mask layer (C) is irradiated with an IR laser in an image-like manner to form a mask on the photosensitive resin layer (B).
• suitable IR lasers include ND / YAG lasers (1064 nm) or diode lasers (eg, 830 nm).
• a laser system suitable for computer plate making technology is commercially available, and for example, CDI (Esco Graphics) can be used.
• the laser system includes a rotating cylindrical drum that holds the original printing plate, an IR laser irradiation device, and a layout computer, and image information is transferred directly from the layout computer to the laser device.
• the flexo printing original plate After writing the image information on the thermal mask layer (C), the flexo printing original plate is fully irradiated with active light through the image-like mask (main exposure). This can be done with the plate attached to the laser cylinder, or the plate can be removed from the laser device and irradiated with a conventional flat plate irradiation unit.
• active ray ultraviolet rays having an emission peak at a wavelength of 330 to 380 nm can be used.
• an LED As the light source, an LED, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a xenon lamp, a zirconium lamp, a carbon arc lamp, a fluorescent lamp for ultraviolet rays, or the like can be used.
• the irradiated plate is then developed, post-exposed, and further exposed by a germicidal lamp to obtain a flexographic printing plate.
• the developing step can be carried out in a conventional developing unit.
• microcell When using a microcell, for example, after selecting a suitable microcell from various microcells mounted on CDI (Esco Graphics), the microcell is applied to an image on a computer, and the image is displayed. It may be used to image the heat-sensitive mask layer.
• CDI Sco Graphics
• Flexographic printing original plate obtained as described above no pinholes are 7,000Myuemu 2 or more of the heat-sensitive mask layer (C), and 2,000 [mu] m 2 or more 7,000Myuemu 2 below those five / It can be m 2 or less.
• the absence of pinholes of 7,000 ⁇ m 2 (radius 47 ⁇ m) or more in the thermal mask layer (C) does not cause significant drawbacks even when microcells are applied.
• the number of pinholes of 2000 ⁇ m 2 (radius 25 ⁇ m) or more and less than 7000 ⁇ m 2 (radius 47 ⁇ m) to 5 / m 2 or less in the heat-sensitive mask layer (C) it is possible to prevent the influence on the microcell.
• the number is preferably 3 or less, more preferably zero.
• the effects of the printing plate of the present invention will be shown by the following examples, but the present invention is not limited thereto.
• the part in the example means a part by mass, and the numerical value indicating the composition ratio in the table also means a part by mass.
• the evaluation in the examples was performed by the following method.
• (1) Surface energy of cover film The surface energy of the cover film was measured by using a wet tension test mixed solution (manufactured by Kanto Chemical Co., Inc.) according to JIS K6768. Specifically, under an atmosphere of 20 ° C. and 60 RH%, wetting tensions at 22.6 mN / m, 25.4 mN / m, 27.3 mN / m, 30 mN / m to 54 mN / m at 1 mN / m intervals. Two drops of the test mixture were dropped on the cover film on the surface of the thermal mask layer, and the wetness and spread of the liquid when spread with a cotton swab was visually evaluated. The value of the mixed liquid that the liquid repelled was used as the surface energy of the cover film.
• the surface roughness (Ra) of the cover film was measured by a confocal method using a confocal laser scanning microscope. Specifically, as a confocal laser microscope, a confocal laser microscope VK9510 manufactured by KEYENCE Corporation was used. The magnification of the objective lens was 50 times. A sample film having a size of 10 cm in length and 10 cm in width was cut out from the cover film. This sample film was placed on the measuring table of a confocal laser scanning microscope, and the measurement was performed while moving the sample film in the vertical direction and / or the horizontal direction by about 5 mm, and the surface roughness (Ra) at 20 points in total was measured. The average of them was calculated and used as the surface roughness (Ra) of the cover film.
• a printing plate was prepared from the original printing plate by the method described later.
• the solid part to which the microcell of the printing plate was applied was magnified 200 times with a KEYENCE digital microscope (VHX5000), and the influence of pinholes on the printing plate was evaluated according to the following criteria.
• the size of the sample was 1 m in length ⁇ 1 m in width.
• ⁇ There is no defect caused by pinholes.
• ⁇ Minor defects caused by pinholes were less than 3 pieces / m 2.
• ⁇ The defect caused by the pinhole was 3 to 10 pieces / m 2 .
• X There were more than 10 defects / m 2 due to pinholes.
• Example 1 Preparation of Photosensitive Resin Composition
• a polymer obtained by polymerizing conjugated diene 86 parts by mass of butadiene latex (Nipol LX111NF, non-volatile content 55%, manufactured by Nippon Zeon Co., Ltd.) and acrylonitrile-butadiene latex (Nipol SX1503, non-volatile content) 42%, 24 parts by mass of Nippon Zeon Co., Ltd., 15 parts by mass of polybutadiene terminal acrylate (BAC45, manufactured by Osaka Organic Chemical Industry Co., Ltd.) having a number average molecular weight of 10000 as an ethylenically unsaturated compound, and a number average molecular weight.
• BAC45 polybutadiene terminal acrylate
• thermal mask layer coating liquid Carbon black dispersion (manufactured by Orient Chemical Industry Co., Ltd., AMBK-8), copolymerized polyamide (PA223, manufactured by Toyo Spinning Co., Ltd.), propylene glycol, methanol 45/5/5 The mixture was mixed at a mass ratio of / 45 to obtain a thermal mask layer coating liquid.
• cover film A polyester film (Toyobo Co., Ltd., Cosmo Shine A4100, thickness 100 ⁇ m) was used as the raw material of the cover film. A chemical etching treatment was performed so that the surface roughness of the smooth surface of Cosmoshine was 0.07 ⁇ m. WET coating of Pyroyl 1050 (long-chain alkyl pendant system, manufactured by Lion Corporation) with a solid content concentration of 0.5% as a mold release agent on the smooth surface of Cosmo Shine with a surface roughness of 0.07 ⁇ m. The film was coated with microgravure so that the amount was 3 g / m 2, and dried at 100 ° C. for 2 minutes to obtain a cover film. The surface coated with Peroyl was the surface on which the heat-sensitive mask layer was provided, and the surface energy of this surface was 32 mN / m and the surface roughness was 0.07 ⁇ m.
• film laminate (I) The cover film is coated with the above-mentioned heat-sensitive mask layer coating solution so that the thickness of the coating film after drying is 2 ⁇ m, dried at 120 ° C. for 5 minutes, and heat-sensitive on the cover film. A mask layer was provided. Subsequently, the above-mentioned protective layer coating liquid was applied as a protective layer so as to have a thickness of 4 ⁇ m to obtain a film laminate (I).
• a photosensitive resin was continuously supplied between the film laminate (I) and the support with an adhesive layer, and a printing original plate (thickness 1.14 mm) was continuously produced by a calendar roll.
• the protective layer on the heat-sensitive mask layer of the film laminate (I) contacts and passes through a roll for adjusting tension in front of the calendar roll.
• the cover film was peeled off from the printing original plate, and the number of pinholes was evaluated. The number of pinholes of 2,000 ⁇ m 2 or more was 0 / m 2 .
• Example 2 In the production of the cover film, the same method as in Example 1 was used except that Peloyl 1050 (long-chain alkyl pendant system, Lion Corporation) was used instead of Peroyl 1050 (long-chain alkyl pendant system, Lion Corporation). went. The evaluation results are shown in Table 1.
• Example 3 In the preparation of the cover film, the same method as in Example 1 was carried out except that Peloyl HT (acrylic, Lion Corporation) was used instead of Peloyl 1050 (long-chain alkyl pendant system, Lion Corporation). The evaluation results are shown in Table 1.
• Example 4 In the production of the cover film, the same evaluation as in Example 1 was performed except that the polyester film (Toyobo Co., Ltd., Cosmo Shine A4100, thickness 100 ⁇ m), which was the raw material, was not subjected to chemical etching treatment. The evaluation results are shown in Table 1.
• Example 5 In the preparation of the cover film, a chemical etching treatment was performed so that the surface roughness of the smooth surface of the polyester film (Toyobo Co., Ltd., Cosmo Shine A4100, thickness 100 ⁇ m), which was the raw material, was 0.15 ⁇ m. Using this raw fabric, the same evaluation as in Example 1 was performed. The evaluation results are shown in Table 1.
• Example 6 In the production of the cover film, the raw polyester film (Toyobo Co., Ltd., Cosmo Shine A4100, thickness 100 ⁇ m) is coated with fine particles (Nippon Shokubai Co., Ltd. Epostal SS, melamine formaldehyde condensate) to reduce the surface roughness. It was set to 0.08 ⁇ m. The same evaluation as in Example 1 was performed using this film. The evaluation results are shown in Table 1.
• Example 7 As a protective layer coating liquid, a water-soluble polyamide resin (P70 manufactured by Toray Industries, Inc.) is used instead of a urethane resin emulsion (Sanyo Chemical Industries, Ltd., Permarin UA-200, solid content concentration 30%). The procedure was the same as in Example 1 except that the solution was dissolved so as to have a concentration of 10% by mass. The evaluation results are shown in Table 1.
• Example 8 As a protective layer coating liquid, polyvinyl alcohol (JR-05 manufactured by Japan Vam & Poval Co., Ltd.) is used instead of urethane resin emulsion (manufactured by Sanyo Kasei Kogyo Co., Ltd., Permarin UA-200, solid content concentration 30%). Except that it was dissolved so that the solid content concentration was 10% by mass, and 30 parts by mass of polyglycerin (polyglycerin 310 manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) was added to 100 parts by mass of polyvinyl alcohol. It was carried out in the same manner as in Example 1. The evaluation results are shown in Table 1.
• Comparative Example 1 The cover film was prepared in the same manner as in Example 1 except that KS847 (silicone type, Shinetsu Silicone Co., Ltd.) was used instead of Peroyl 1050 (long-chain alkyl pendant type, Lion Corporation). The evaluation results are shown in Table 1.
• Comparative Example 2 In the preparation of the cover film, the same method as in Example 1 was carried out except that Pyroyl 1050 (long-chain alkyl pendant system, Lion Corporation) was not applied. The evaluation results are shown in Table 1.
• Comparative Example 3 In the preparation of the cover film, a chemical etching treatment was performed so that the surface roughness of the smooth surface of the polyester film (Toyobo Co., Ltd., Cosmo Shine A4100, thickness 100 ⁇ m), which was the raw material, was 0.004 ⁇ m. Using this raw fabric, the same evaluation as in Example 1 was performed. The evaluation results are shown in Table 1.
• Comparative Example 4 In the preparation of the cover film, a chemical etching treatment was performed so that the surface roughness of the smooth surface of the polyester film (Toyobo Co., Ltd., Cosmo Shine A4100, thickness 100 ⁇ m), which was the raw material, was 0.25 ⁇ m. Using this raw fabric, the same evaluation as in Example 1 was performed. The evaluation results are shown in Table 1.
• Comparative Example 5 In the production of the film laminate (I), the same method as in Example 1 was carried out except that the protective layer was not provided. The evaluation results are shown in Table 1.
• Comparative Example 1 since the surface energy was lower than the range of the present invention, the adhesive force between the heat-sensitive mask layer and the cover film was weak, and scratches (pinholes) occurred during roll contact in the processing process.
• Comparative Example 2 since the surface energy was higher than the range of the present invention, when the cover film was peeled off from the printing original plate, the heat-sensitive mask layer was transferred to the cover film side, and pinholes were generated in the printing original plate.
• Comparative Example 3 since the surface roughness of the surface in contact with the heat-sensitive mask layer was lower than the range of the present invention, the cover film was too smooth and the film was not slippery, and pinholes were generated during roll contact in the processing process.
• Comparative Example 4 since the surface roughness of the surface in contact with the heat-sensitive mask layer is higher than the range of the present invention, a large force is applied to the convex portion of the heat-sensitive mask layer during roll contact in the processing process, and scratches (pin holes) occur. did.
• Comparative Example 5 unlike Examples 1 to 8, since there was no protective layer on the heat-sensitive mask, a large number of scratches (pinholes) occurred during roll contact in the processing process.
• the flexographic printing original plate of the present invention is configured so that the surface energy and surface roughness (Ra) of the surface of the cover film in contact with the heat-sensitive mask layer are within a specific range, and further between the photosensitive resin layer and the heat-sensitive mask layer. Since a protective layer formed of a polymer compound dispersible in the developing solution is provided on the surface, a flexographic printing master plate in which the pinholes of the thermal mask layer are small and reduced can be easily obtained, and as a result, defects due to pinholes can be easily obtained. It is possible to provide a flexographic printing plate with almost no. Therefore, the flexographic original plate of the present invention is extremely useful in the art.

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• 2020
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