JP2010234636A - Method for manufacturing flexographic printing original plate for laser engraving - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently manufacture a thick flexographic printing original plate for laser engraving. <P>SOLUTION: The method for manufacturing a flexographic printing original plate for laser engraving includes at least (1) a step of preparing a reactive resin composition, (2) a step of casting the reactive resin composition on a release body, and (3) a step of forming an independent sheet by drying the cast film and by releasing the same from the release body. In the method, double-side drying is possible by forming the independent sheet, so that the time necessary for drying a solvent from the reactive resin composition can be shortened, and a thick film product such as a flexographic printing original plate is efficiently manufactured. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a printing plate precursor, and more particularly to a method for producing a flexographic printing plate precursor for laser engraving.

  As a method for forming a flexographic printing plate by forming irregularities (reliefs) on the surface, a flexographic printing plate precursor made of a photosensitive resin composition is exposed with ultraviolet light through an original image film, and an image portion is selectively cured. A method of removing uncured portions using a developer, so-called analog plate making, is well known.

  Analog plate making requires an original film using a silver salt material, and thus requires time and cost for producing the original film. Furthermore, since chemical processing is required for developing the original image film and processing of the development waste liquid is also required, there is a disadvantage in environmental hygiene. Therefore, in recent years, a method of engraving a relief with a laser has been proposed.

  Patent Document 1 proposes a method of forming a printing relief by irradiating a photosensitive flexographic printing plate precursor with ultraviolet light and engraving the photocured plate with a carbon dioxide gas laser. However, in the case of this method, since the necessary mechanical strength of the printing plate is expressed by photocuring, a substance that blocks ultraviolet light, such as carbon black, cannot be added.

  For example, Patent Document 2 and Patent Document 3 propose to add a substance that absorbs infrared rays to the elastomer layer to be laser-engraved for the purpose of increasing engraving sensitivity. However, since this type of substance, such as carbon black, also has an ultraviolet light absorption function, it is difficult to photocur the entire thickness of the elastomer layer with ultraviolet light. Therefore, it has been proposed to add a thermal polymerization initiator to the elastomer layer and thermally cross-link this layer. However, when actually forming a layer, a kneading or twin screw extruder can cause thermal crosslinking that is too fast during production due to its high working temperature and / or high shear stress, and thus stable production is difficult.

  Further, since the thickness of the flexographic printing plate is usually as thick as 0.5 to 7 mm, there is a problem that the production efficiency is remarkably lower than that of a thin film-formed product having a thickness of 0.1 to 10 μm such as a lithographic plate.

  Several methods for forming a thick film product of a flexographic printing plate precursor for laser engraving have been proposed.

  Patent Document 4 proposes a method in which a solution of a crosslinkable resin composition is cast on a substrate, but there is a problem that solvent evaporation is slow and production efficiency is poor because it is single-sided drying. Moreover, although there exists description of the crosslinkable resin composition containing a thermal-polymerization initiator, it was difficult to manufacture this composition thermally stably.

  Patent Document 5 proposes a method of kneading and extruding in a solvent-free system, but (1) the carrier resin is limited to a polymer having a low thermoplasticity or a low heat melting temperature, and (2) since it is substantially solvent-free, There was a problem that a high share was applied during kneading and it was not suitable for molding a reactive resin composition.

  Patent Document 6 proposes a method in which a reactive resin composition is divided and installed in two layers and mass transfer of the composition, particularly the thermal polymerization initiator, is performed over time. However, it is difficult to transfer the mass with high accuracy. Therefore, it was not suitable for stable production.

US Pat. No. 5,259,311 (Claims) JP 7-506780 A (pages 5 and 8) JP 7-505840 A (7th page, 11th page and 12th page) JP 2006-2061 A (pages 10, 16 and 17) JP 2008-229875 A (pages 7 to 10) Japanese translation of PCT publication No. 2004-522618 (Claims)

  It is an object to efficiently produce a thick-film flexographic printing plate precursor for laser engraving.

  (1) a step of preparing a reactive resin composition, (2) a step of casting the reactive resin composition on a mold release body, (3) an independent sheet that is dried by peeling the casting film from the mold release body. A process for producing a flexographic printing plate precursor for laser engraving, which comprises at least a step of forming a process.

  Drying efficiency is improved, and a thick-film flexographic plate precursor can be manufactured at low cost.

It is the schematic of a process (1) and a process (2). It is the schematic of a process (3) and a process (3 '). It is the schematic of a process (4). It is the schematic of a process (5).

  The flexographic printing plate precursor for laser engraving of the present invention has at least an engraving layer to be engraved. If necessary, a support may be provided, or a temporary support may be provided on the surface of the engraving layer. Further, an adhesive layer may be provided between the support and the engraving layer, and a slip coat layer may be provided for the purpose of assisting peeling of the temporary support from the engraving layer.

  The present invention proposes how efficiently an engraving layer that is a functional layer of a flexographic printing plate precursor for laser engraving can be produced. The thickness of the flexographic printing plate is usually as thick as 0.5 mm to 7 mm, and the layer occupying most of the flexographic printing plate, in the present invention, the thickness of the engraving layer is as thick as 0.4 mm to 6 mm. As a method for producing such a thick engraving layer, the following mode is proposed.

  According to a preferred embodiment for producing the engraving layer of the present invention, (1) a step of preparing a reactive resin composition, (2) a step of casting the reactive resin composition on a mold release body, (3) casting It includes a step of drying the film and peeling it from the mold release to form an independent sheet.

  The reactive resin composition as used herein refers to a composition in which a polymerization reaction, a condensation reaction, or a crosslinking reaction proceeds by the action of light, heat, electron beam or the like. The reactive resin composition preferably contains a solvent because the reactivity of the material that can be used is increased. Further, if the reactive resin composition does not contain a solvent, a high temperature is required to mix the reactive resin composition, and the concentration of the reactant becomes high, so that the reactive resin composition can be produced stably. It becomes difficult. The content of the solvent in the reactive resin composition is preferably 70% by weight or less, and more preferably 10% by weight to 50% by weight with respect to the total weight of the reactive resin composition. By setting the content of the solvent to 70% by weight or less, the volatilization time of the solvent can be suppressed to an extent that can be adapted to the manufacturing process. The boiling point of the solvent is preferably 110 ° C. or less, and more preferably 80 ° C. or less. This is because by setting the boiling point of the solvent to 110 ° C. or lower, the solvent volatilization rate is increased and the production cost is reduced. Examples of such a solvent include water, methanol, ethanol, n-propanol, isopropanol, sec-butanol, tert-butanol, tetrahydrofuran, and methyl ethyl ketone. These solvents may be used alone or in combination of two or more. A solvent having a boiling point higher than 110 ° C. may be contained, but in view of the volatilization efficiency of the solvent, it should be 10% by weight or less of the total solvent.

  Details of the reactive resin composition will be described below.

  The functions required for the engraving layer are mainly A ink resistance, B printing durability, and C laser engraving ability.

  By using the engraving layer having A-ink resistance, the physical properties of the engraving layer do not change during flexographic printing, or there is little change in physical properties, and long-run printing can be performed stably. It is preferable that the engraving layer does not swell or has a low degree of swelling with respect to inks generally used for flexographic printing (for example, water-based ink, UV ink, solvent ink). It is preferable that the rate of change in the weight, thickness, and hardness of the engraving layer is -10% to + 10% before and after immersion in a predetermined ink at 30 ° C. for 24 hours. The hardness can be easily measured with a Shore A hardness meter generally used for measuring the hardness of a flexographic plate.

  The swelling degree of the engraving layer can be suppressed by using a main component polymer having a polarity different from that of the ink. For example, (i) to obtain an engraving layer resistant to water-based ink can be achieved by using a water-insoluble rubber as a main component polymer. Such rubbers include butadiene rubber, nitrile rubber, styrene rubber, isoprene rubber, synthetic rubber such as butyl rubber, styrene / butadiene / styrene block copolymer (SBS), styrene / isoprene / styrene block copolymer (SIS). A thermoplastic elastomer such as can be used.

  (Ii) In order to obtain a UV ink-resistant engraving layer, the above rubber may be used, or a soluble resin such as polyamide or partially saponified polyvinyl alcohol may be used. Since UV ink is basically solvent-free, the range of polymer selection is relatively wide, but the type of monomer used as the main component in UV ink varies depending on the ink manufacturer and ink product number. However, some inks may lack resistance. Among these, partially saponified polyvinyl alcohol, which is a water-soluble resin, exhibits resistance to many monomers due to its strong hydrogen bonding force, and can be preferably used as a main component polymer for UV ink resistance. As the partially saponified polyvinyl alcohol, one in which at least a part of the hydroxyl group is modified can be suitably used. A polymer in which at least a part of the hydroxyl group is modified to a (meth) acryloyl group is particularly preferably used. By directly introducing an unreacted crosslinkable functional group into the polymer component, the strength of the relief layer can be increased without using a large amount of a polyfunctional monomer as an ethylenically unsaturated monomer described later, and the flexibility of the relief layer This is because both strength and strength can be achieved.

  The content of the main component polymer in the engraving layer is preferably 15% by weight to 80% by weight, and more preferably 30% by weight to 65% by weight with respect to the total solid content of the engraving layer. By setting the content of the main component polymer to 15% by weight or more, necessary ink resistance can be obtained, and by setting it to 80% by weight or less, it can be used as a flexographic printing plate without lack of other components. This is because sufficient flexibility can be obtained.

  The engraving layer may contain a polymer other than the main component, and the total content of the engraving layer in that case is preferably 30% by weight to 80% by weight with respect to the total solid content of the engraving layer, More preferably, it is 40 to 70% by weight. By making the total content of the polymer 30% by weight or more, it is possible to prevent cold flow of the original plate, and by making it 80% by weight or less, other components are not deficient and can be used as a flexographic printing plate. This is because sufficient printing durability can be obtained.

  B printing durability refers to the mechanical strength that can withstand printing. By using a flexographic printing plate that has printing durability, even after long run printing, there is no relief chipping or relief collapse, and stable printing. You can get things.

  To impart printing durability to the engraving layer, it can be achieved by introducing a crosslinked structure into the engraving layer. As the means, there can be mentioned a method in which (i) an ethylenically unsaturated monomer and (ii) a polymerization initiator are added to the engraving layer, and the monomer is polymerized using light or heat as a trigger. (I) The ethylenically unsaturated monomer is compatible with the above polymer component and contains at least one polymerizable ethylenically unsaturated double bond. Suitable monomers generally have a boiling point of 100 ° C. or higher under atmospheric pressure and a weight average molecular weight of 3000 or less, preferably 2000 or less. Monomers or polyfunctional alcohols, amines, amino alcohols, hydroxy ethers or hydroxy esters, and (meth) acrylic acid esters or amides are preferred monomers. Examples include polyethylene glycol (meth) acrylate, glycerin di (meth) acrylate, and 1,6-hexanediol di (meth) acrylate. Mixtures of different monomers can also be used.

  The content of the ethylenically unsaturated monomer in the engraving layer is preferably 10% by weight to 60% by weight and more preferably 15% by weight to 40% by weight with respect to the total solid content of the engraving layer. Printing durability sufficient to be used as a flexographic printing plate can be obtained by setting the content of ethylenically unsaturated monomer to 10% by weight or more, and flexibility sufficient to be used as a flexographic printing plate by setting the content to 60% by weight or less. Is obtained.

  (Ii) The polymerization initiator acts as an initiator for cross-linking of the ethylenically unsaturated monomer, but also contributes to the cross-linking when a cross-linkable functional group is introduced into the polymer. As such a polymerization initiator, for example, it is preferable to use a photopolymerization initiator that generates radicals by irradiating an actinic ray such as ultraviolet light, but generates radicals by heating (b) ) A thermal polymerization initiator may be used.

  (A) As a photopolymerization initiator, acetophenone compounds such as diethoxyacetophenone, benzyldimethyl ketal, 1-hydroxycyclohexyl-phenylketone, benzoin compounds such as benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, Benzophenone, benzophenone compounds such as methyl o-benzoylbenzoate, 4-benzoyl-4′-methyl-diphenyl sulfide, thioxanthone compounds such as 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, Triethanolamine, triisopropanolamine, ethyl 4-dimethylaminobenzoate, 4,4′-bisdiethylaminobenzophenone, 4,4 ′ And amine compounds such as bis-dimethylamino benzophenone (Michler's ketone), benzyl dimethyl ketal, benzyl-based, camphorquinone, 2-ethyl anthraquinone, such as 9,10-phenanthrenequinone is preferably used. You may use these individually or in combination of 2 or more types.

  (B) As the thermal polymerization initiator, acetyl peroxide, cumyl peroxide, tert-butyl peroxide, benzoyl peroxide, lauroyl peroxide, potassium persulfate, diisopropyl peroxycarbonate, tetralin hydroperoxide, tert-butyl hydroperoxide, Peroxides such as tert-butyl peracetate, tert-butyl perbenzoate, 2,2′-azobispropane, 1,1′-azo (methylethyl) diacetate, 2,2′-azobisisobutyramide, An azo compound such as 2,2′-azobisisobutyronitrile, benzenesulfonyl azide, 1,4-bis (pentamethylene) -2-tetrazene and the like are preferably used. You may use these individually or in combination of 2 or more types.

  The content of the polymerization initiator in the engraving layer is preferably 0.01% by weight to 10% by weight and more preferably 0.1% by weight to 3% by weight with respect to the total solid content of the engraving layer. By setting the content of the polymerization initiator to 0.01% by weight or more, the engraving layer is rapidly crosslinked, and by setting it to 10% by weight or less, other components are not insufficient and used as a flexographic printing plate. This is because sufficient printing durability can be obtained.

  The C laser engraving property refers to performance that can be engraved with a laser for engraving, and can be achieved by adding an absorber in the wavelength region of the laser to the engraving layer. Since the wavelength region of the carbon dioxide laser is in the vicinity of 11 μm, and the polymer generally has absorption in this wavelength region, it is not always necessary to add a laser absorber. On the other hand, the oscillation wavelength of near-infrared lasers such as semiconductor lasers, YAG lasers, and fiber lasers is 860 to 1150 mm, and since there are few polymers that absorb in this wavelength region, lasers that support near-infrared lasers In order to obtain a material for engraving, it is preferable to add a laser absorber.

  Examples of such laser absorbers include phthalocyanine compounds, cyanine compounds, squarylium dyes, polymethine dyes, nigrosine dyes, carbon black, chromium oxide, iron oxide, iron, aluminum, copper, and metal powders such as zinc.

  In addition, the engraving layer may contain additives such as a plasticizer, a heat stabilizer, a light absorber, and a dye as necessary.

  Hereinafter, the step (1) of preparing the reactive resin composition will be described with reference to FIG. The reactive resin composition can be produced by dissolving a polymer, an ethylenically unsaturated monomer and a polymerization initiator, and, if necessary, a laser absorber, a plasticizer, a heat stabilizer and the like in a solvent. Of the components other than the solvent, which is the solid content that actually forms the engraving layer, the dissolution rate of the polymer tends to be rate limiting, so it is preferable to first add and mix the other components after dissolving the polymer in the solvent first. . Moreover, it is preferable to add and mix the ethylenically unsaturated monomer and the polymerization initiator having reactivity at the final stage of preparation. When preparing the reactive resin composition, for the purpose of shortening the time required for the preparation, further reducing the solvent required for dissolution, and for the purpose of shortening the volatilization time of the solvent in the step (3) described later, It is preferable to mix under heating conditions.

  The temperature during polymer dissolution is preferably 30 ° C to 150 ° C, more preferably 70 ° C to 130 ° C. By setting the polymer dissolution temperature to 30 ° C. or higher, the polymer dissolution time can be shortened, and by setting the polymer dissolution temperature to 150 ° C. or lower, the utility cost required for dissolution can be suppressed. In the case where the polymer is dissolved at a temperature higher than the boiling point of the solvent, this can be dealt with by performing the dissolution in a sealed pressure vessel. The polymer dissolution is preferably performed in a nitrogen atmosphere from the viewpoint of preventing powder explosion.

  The storage temperature after adding the reactive ethylenically unsaturated monomer or polymerization initiator is preferably 30 ° C to 90 ° C, more preferably 40 ° C to 90 ° C. By setting the storage temperature to 30 ° C. or higher, there is no need for the use cost of a cooling chiller for heat retention, and by setting the storage temperature to 90 ° C. or lower, the reaction progress of the reactive resin composition is delayed, and the reactive resin composition Can be stored stably.

  Polymer dissolution, additive mixing, and storage of the reactive resin composition may be performed in the same reaction container or in separate containers.

  In the reactive resin composition, the rate of increase in the viscosity of the composition at the storage temperature is preferably within 10% in 24 hours, and more preferably within 5%. The reactive resin composition may be stored in the sealed container used for the preparation or in a separate container, but in order to prevent composition change due to solvent volatilization in the reactive resin composition, it should be stored in a sealed system. Preferably there is. In addition, the reactive resin composition of the present invention often has a high viscosity of, for example, 50 poise or more due to the content of the solvent, and may be pressurized to feed the reactive resin composition from the container. The storage of the functional resin composition is more preferably a pressure vessel.

  After the liquid adjustment, it is preferable to perform defoaming to remove bubbles in the reactive resin composition. Defoaming can also be achieved by placing for a long time, but if the reactive resin composition has a high viscosity, the placing time becomes long. Therefore, it is preferable to degas by depressurization. Since not only bubbles but also a small amount of solvent is volatilized by decompression, a slight concentration may be performed. By managing the amount of concentration, a reactive resin composition having a specific composition ratio can be obtained.

  Next, step (2) will be described with reference to FIG. In the step (2) of the present invention, the reactive resin composition prepared in the step (1) is cast on the mold release body (21) to form a wet film (22). Since this wet film (22) forms the engraving layer after the solvent is dried by the drying means (31), it is necessary to cast a wet film with good film thickness accuracy from the viewpoint of controlling the film thickness of the flexographic printing plate precursor. is there. Therefore, the reactive resin composition is preferably discharged through a die (14) designed so that the composition spreads uniformly in the width direction. Examples of such a die (14) include a T die, a coat hanger die, a fish tail die, and a slit die coater. Among these, the coat hanger die and the fish tail die are particularly preferably used as a die for discharging the reactive resin composition because of less abnormal retention in the die.

  From the viewpoint of temperature control, the reactive resin composition preferably connects the storage container (11) and the base (14) through a temperature-controlled liquid feed line (12). The liquid feed line (12) refers to a pipe for feeding the reactive resin composition from the reactive resin composition container (11) to the base (14). Examples of such a liquid feed line (12) include a double pipe and a single pipe wound with a ribbon heater. In terms of thermal efficiency and temperature stability, it is preferable to use a double tube. The reactive resin composition passing through the inner pipe can be kept at a constant temperature by circulating the outer pipe of the double pipe with a temperature-controlled heat medium such as hot water.

  In order to send a fixed amount to the base (14) constantly, (i) the reactive resin composition is forcibly supplied from the storage container (11) to the fluid transporter (13), and (ii) the fluid transporter ( This can be achieved by feeding a constant amount to the base (14) in step 13).

  (I) As means for forcibly supplying the reactive resin composition from the storage container (11) to the fluid transporter (13), a method of sucking the reactive resin composition with an aspirator or the like, a storage container for the reactive resin composition ( 11) can be arranged at a higher altitude than the fluid transporter (13), and can be naturally fed by gravity, or a method of pressurizing the storage container (11) and pumping the reactive resin composition.

  (Ii) As a fluid transporter (13), a Mono pump, a turbine pump, a volute pump, a multistage pump, an axial pump, a piston pump, a plunger pump, a diagram pump, a gear pump, a Nash pump, a friction pump, an acid egg, and a jet pump Can be selected as appropriate depending on the amount of liquid fed, the viscosity of the liquid, the internal pressure of the pipe, and the like.

  Further, in order to obtain a wet film (22) having a uniform film thickness accuracy in the flow direction, the release body (21) is preferably transported at a constant speed by a speed-controlled transport means, for example, a conveyor belt (23). . Alternatively, the position of the mold release body (21) may be fixed, and the die (14) may be moved along the mold release body at a constant speed.

  The mold release body (21) is solid with the casting film (22) after volatilizing the solvent from the casting film (22), after volatilizing a part of the solvent, or before volatilizing the solvent. This refers to a carrier that can peel the casting film alone without sticking. Examples of such a release body (21) include silicone resin, fluorine resin, PET film, PP film and the like. The release body (21) only needs to have its surface covered with these materials. For example, the release body (21) may be a stainless steel plate coated with a silicone resin. Moreover, a mold release body may be integrated with the said conveyor belt (23), and may just be mounted on a conveyor belt (23).

  Next, steps (3) and (3 ') will be described with reference to FIG. In the step (3) of the present invention, the casting film (22) is dried and peeled from the release body (21) to form an independent sheet (32). The independent sheet (32) as used herein refers to a sheet formed only from the reactive resin composition, and the sheet strength at 25 ° C. is preferably 6 N / cm or more, and 10 N / cm or more. Is more preferable. By setting the sheet strength to 6 N / cm or more, an independent sheet can be peeled without cutting the sheet. A sheet strength measurement sample is prepared by punching a sheet into a shape having a measurement width of 5.0 mm using a dumbbell described in JIS K 6253. The upper part of the spring-type balance is fixed, the measurement sample is attached to the lower part, the measurement sample is pulled downward at a speed of about 2 to 4 cm / sec, and the scale A [unit: g] when the sheet breaks is read. When this is measured 5 times and the average value is Ax [unit], the sheet strength P [unit: N / cm] of the sheet is calculated by P = 9.8 * Ax / (1000 * 0.5). it can.

  Peeling of the casting film from the mold release body (21) can be achieved by drying the casting film (22) and volatilizing the solvent. In drying in the casting film form, the longer the drying time, the more the solvent is volatilized, so that the sheet strength increases and it becomes easier to form an independent sheet. However, since the drying surface is only the surface opposite to the release body (21) and the volatilization efficiency of the solvent is poor, it is preferable that the drying before peeling is limited to the extent that the sheet strength can be obtained. The drying temperature at this time is preferably lower than the boiling point of the solvent used. This is because if the drying is performed at a temperature equal to or higher than the boiling point of the solvent, bubbles are likely to be generated in the sheet due to the bumping of the solvent.

  It is preferable to further include a step (3 ') of volatilizing the solvent from the independent sheet after the step (3). The independent sheet (32) is not covered on both sides and can be dried on both sides. By drying on both sides, a thick film product having a dry film thickness of 0.4 mm to 6 mm required for the flexographic plate can be efficiently produced. The drying temperature at this time is also preferably lower than the boiling point of the solvent used in the same manner as in step (3). This is because if the drying is performed at a temperature equal to or higher than the boiling point of the solvent, bubbles are likely to be generated in the sheet due to the bumping of the solvent.

  Further, if necessary, the sheet obtained by (4) step (3) shown in FIG. 3, that is, the engraving layer sheet (32), and the support (42) coated with the adhesive layer are laminated to form a sheet / adhesion. A step of forming a layer / support laminate (43) may be included. The support is installed for the purpose of imparting dimensional stability and for the purpose of improving handling by giving a moderate strength to the flexible engraving layer.

  In order to laminate the engraving layer sheet (32) and the support (42) coated with the adhesive layer, a method of directly pressing the engraved layer sheet (32) and the support (42) coated with the adhesive layer, Examples thereof include a solvent or a chemical solution capable of swelling the engraving layer sheet, and a method in which the sheet or the adhesive layer is wetted with a monomer having an affinity for the engraving layer and then both are pressure-bonded. Examples of the pressure bonding means include a method of pressing with a press machine and a method of nip with a calendering roll (41). These pressure bonding may be performed, for example, under conditions in which the press machine or roll is heated to an appropriate temperature, for example, 100 ° C. .

  The material used for the support in the present invention is not particularly limited, but those that are dimensionally stable are preferably used. For example, metals such as steel, stainless steel, and aluminum, polyesters (for example, PET, PBT, PAN), and polyvinyl chloride. Examples thereof include plastic resins, synthetic rubbers such as styrene-butadiene rubber, and plastic resins reinforced with glass fibers (such as epoxy resins and phenol resins). Among these, a PET (polyethylene terephthalate) film or a steel substrate is preferably used. The thickness of the support is generally preferably 50 μm to 350 μm, more preferably 75 μm to 250 μm.

  Since the engraving layer sheet (32) and the support often do not have adhesiveness to each other, an adhesive layer may be provided for the purpose of enhancing the adhesive force between the two layers. The adhesive layer can obtain the target performance by providing a material having affinity for both the engraving layer sheet (32) and the support. For example, when the engraved layer sheet (32) contains partially saponified polyvinyl alcohol and the support is a polyester film, an engraved layer sheet (32) is provided by providing an adhesive layer having a composition containing partially saponified polyvinyl alcohol and a polyester resin. And the support can be firmly bonded. The material used for the adhesive layer is preferably the same or the same kind of polymer as the material used for the engraving layer sheet (32) or the support. The same kind of polymer means a compound having the same main skeleton but different molecular weight, purity, and functional group amount. That is, when the engraving layer contains partially saponified polyvinyl alcohol having a polymerization degree of 500 and an average saponification degree of 82%, the adhesive layer may contain partially saponified polyvinyl alcohol having the same specifications, or a part of the hydroxyl group may be modified with carboxylic acid. The partially saponified polyvinyl alcohol may be contained, or partially saponified polyvinyl alcohol having a different saponification degree, for example, 70% saponification degree may be contained.

  The adhesive layer may be a single layer or a multilayer of two or more layers. If the material of the engraving layer sheet and the polarity of the support, for example, the solubility parameter (SP value) are close to each other, the respective materials can be easily mixed to form one adhesive layer. For example, partially saponified polyvinyl alcohol (SP value) : 12.6) and polyester resin (SP value: 10.7), when the polarities are significantly different, the compatibility is poor and it is difficult to mix them. In such a case, in order to improve the compatibility, it is possible to add a material having an intermediate polarity (for example, phenol resin) as a compatibilizing agent, but it is also possible to make the adhesive layer into two layers. Yes. The second adhesive layer on the engraving layer sheet (32) side contains partially saponified polyvinyl alcohol which is a material of the engraving layer, the first adhesive layer on the support side contains the same type of polyester resin as the support, and the first adhesive layer The desired adhesion can be obtained by adding a material for bonding the second adhesive layer to one of the layers. The material for adhering both layers may be the above-mentioned intermediate polarity material, or may be one utilizing a chemical reaction such as polymerization of a monomer or condensation of an isocyanate and a hydroxyl group.

  Here, the adhesive force means both the adhesive force between the support / adhesive layer and the adhesive layer / engraving layer. The adhesive force between the support / adhesive layer is such that when the adhesive layer and the engraved layer are peeled from the laminate comprising the support / adhesive layer / engraved layer at a rate of 400 mm / min, the peel force per 1 cm width of the sample is 1.0 N. / Cm or higher or non-peelable, more preferably 3.0 N / cm or higher or non-peelable. Regarding the adhesive force between the adhesive layer / engraved layer, when the adhesive layer is peeled from the adhesive layer / engraved layer at a speed of 400 mm / min, the peel force per 1 cm width of the sample may be 1.0 N / cm or more or cannot be peeled off. Preferably, it is more preferably 3.0 N / cm or more or non-peeling.

  Further, if necessary, (5) a step of laminating the engraving layer sheet (32) and the temporary support (52) shown in FIG. 4 may be included. The temporary support (52) is installed for the purpose of preventing scratches or dents on the surface of the engraving layer, or for improving the handleability by giving a moderate strength to the flexible engraving layer. This is because the engraving layer becomes a portion where the relief is formed after laser engraving, and the surface of the relief top portion functions as an ink deposition portion.

  If the temporary support (52) is too thin, the effect of preventing scratches and dents cannot be obtained, and if it is too thick, the handling becomes inconvenient and the cost increases. Therefore, the thickness of the temporary support (52) is preferably 25 μm to 500 μm, more preferably 50 μm to 200 μm.

  As the temporary support (52), a known material as a protective film for a printing plate, for example, a polyester film such as PET (polyethylene terephthalate) or a polyolefin film such as PE (polyethylene) or PP (polypropylene) is used. Can do. The surface of the film may be plain or matted.

  When providing a temporary support (52) on the engraving layer, the temporary support (52) must be peelable. If the temporary support cannot be peeled off or is difficult, or conversely, if the adhesion between the engraving layer and the temporary support (52) is weak and easily peeled, the same or the same kind of reactive resin composition is used between the two layers. A layer containing a polymer may be provided. Adhesiveness with the engraving layer formed from the reactive resin composition can be obtained by providing a layer containing the same or the same kind of polymer as in the reactive resin composition. The polymer content in the layer containing the same or the same kind of polymer as in the reactive resin composition is preferably 70% by weight or more, more preferably 90% by weight or more. By setting the polymer content to 70% by weight or more, the content of tacky low-molecular components, for example, ethylenically unsaturated monomers, is relatively low. Decreases and the temporary support (52) is easily peeled off.

  From the laminate of the engraving layer (54) or engraving layer sheet (32) (and the layer containing the same or the same polymer as in the reactive resin composition) / temporary support (52) to the temporary support (52) Is peeled at a speed of 200 mm / min, the peel force per 1 cm is preferably 5 to 200 mN / cm, more preferably 10 to 150 mN / cm. If it is 5 mN / cm or more, the temporary support (52) can be worked without peeling during the work, and if it is 200 mN / cm or less, the temporary support (52) can be peeled without difficulty. The layer containing the same or the same kind of polymer as in the reactive resin composition may remain on the engraving layer side after the temporary support (52) is peeled off, or may be peeled off together with the temporary support (52). good.

  The laminate in step (5) can be performed by a method of pressure bonding the temporary support (52) and the engraving layer sheet (32) with a heated calendar roll (51) or the like, and the surface of the engraving layer sheet (32) with a small amount of solvent. After impregnation, the temporary support (52) can be brought into close contact. Alternatively, the engraving layer sheet (32) and the temporary support (52) can be laminated by casting and sandwiching a composition (53) having the same or similar composition as the engraving layer sheet (32). it can. In particular, the latter method is preferably used because the thickness after lamination can be made uniform by passing a calender roll (51) whose clearance is uniformly controlled after being sandwiched. At this time, the calendar roll (51) may be heated as necessary. In the latter method, the engraving layer sheet (32) and the composition (53) having the same or similar composition as the engraving layer sheet are integrated with time to form the engraving layer (54). In other cases, the engraving layer sheet (32) becomes the engraving layer (54).

  Further, (6) a step of crosslinking the engraving layer may be included. In the case where the engraving layer (54) contains a photopolymerization initiator, ultraviolet light is emitted through the temporary support (52), after the temporary support (52) is peeled off, or through the support. The engraving layer can be cross-linked by irradiating with an actinic ray. When the engraving layer contains a thermal polymerization initiator, the engraving layer (54) can be crosslinked by heating the flexographic printing plate precursor for laser engraving. Examples of the heating means include a method of leaving the original plate in a hot air oven or a far infrared oven for a predetermined time, or a method of contacting a heated roll for a predetermined time.

  Hereinafter, the present invention will be described in detail with reference to examples.

<Preparation of the support body 1 which apply | coated the adhesive layer>
70 parts by weight of “Byron” 31SS (toluene solution of unsaturated polyester resin, manufactured by Toyobo Co., Ltd.) and 2 parts by weight of “PS-8A” (benzoin ethyl ether, manufactured by Wako Pure Chemical Industries, Ltd.) After heating at 30 ° C. for 2 hours and cooling to 30 ° C., 7 parts by weight of ethylene glycol diglycidyl ether dimethacrylate was added and mixed for 2 hours. Further, 25 parts by weight of “Coronate” 3015E (ethyl acetate solution of polyvalent isocyanate resin, manufactured by Nippon Polyurethane Industry Co., Ltd.) and 14 parts by weight of “EC-1368” (industrial adhesive, manufactured by Sumitomo 3M Co., Ltd.) This was added to obtain a coating solution composition for the first adhesive layer.

  50 parts by weight of “Gohsenol” KH-17 (polyvinyl alcohol having a saponification degree of 78.5% to 81.5%, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) is mixed with “Solmix” H-11 (alcohol mixture, Nippon Alcohol Co., Ltd.). )) After being dissolved in a mixed solvent of 200 parts by weight and 200 parts by weight of water at 70 ° C. for 2 hours, 1.5 parts by weight of “Blenmer” G (glycidyl methacrylate, manufactured by NOF Corporation) was added, and 1 After mixing for a while, 3 parts by weight of (dimethylaminoethyl methacrylate) / (2-hydroxyethyl methacrylate) / (methacrylic acid) copolymer (copolymerization ratio: 67/32/1), “Irgacure” 651 (benzyldimethyl ketal) Ciba Geigy Co., Ltd.) 5 parts by weight, “epoxy ester” 70PA (propylene glycol diglycidyl ether acrylic) 21 parts by weight of acid adduct (manufactured by Kyoeisha Chemical Co., Ltd.) and 20 parts by weight of ethylene glycol diglycidyl ether dimethacrylate were added and mixed for 90 minutes. After cooling to 50 ° C., “Megafac” F-470 (perfluoroalkyl) 0.1 part by weight of a group-containing oligomer (Dainippon Ink Chemical Co., Ltd.) was added and mixed for 30 minutes to obtain a coating solution composition for the second adhesive layer.

  Use a bar coater to dry the coating liquid composition for the first adhesive layer on the “Lumirror” # 188T60 (polyester film, manufactured by Toray Industries, Inc.) having a thickness of 188 μm to be used as a support. After coating, place in a 180 ° C. oven for 3 minutes to remove the solvent, and then apply a coating solution composition for the second adhesive layer on the bar coater so that the dry film thickness is 18 μm. And dried for 3 minutes to obtain a support 1 coated with an adhesive layer, which is a laminate of the second adhesive layer / first adhesive layer / support.

  The first adhesive layer is made of a polyester resin as a main raw material and has a composition similar to that of the polyester film as the support, and thus has a good adhesive force with the support. Since the main material of the second adhesive layer is polyvinyl alcohol, the second adhesive layer has a good adhesive force with respect to the engraving layer that is also made of polyvinyl alcohol as the main material. The first adhesive layer and the second adhesive layer both contain a (meth) acrylate monomer, and the adhesive strength of both layers is good.

<Preparation of temporary support 1 coated with slip coat layer>
4 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- It was dissolved in a mixed solvent of 10 parts by weight of butanol to obtain a coating liquid composition for a slip coat layer.

  On a 100 μm thick polyester film “Lumirror” # 100S10 (manufactured by Toray Industries, Inc.), the above coating composition for the slip coat layer is applied using a bar coater so that the dry film thickness is 1.0 μm. And it dried at 100 degreeC for 25 second, and obtained the temporary support body 1 which apply | coated the slip coat layer which is a laminated body of a slip coat layer / temporary support body.

<Synthesis of hydrophilic 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. Heating was carried out for 1 hour, then water was removed, and a hydrophilic polyamide resin 1 having a relative viscosity (1 g of polymer dissolved in 100 ml of chloral hydrate and measured at 25 ° C.) of 2.50 was obtained.

<Synthesis of modified polyvinyl alcohol 1>
In a flask equipped with a condenser tube, partially saponified polyvinyl alcohol “GOHSENOL” KL-05 (saponification degree: 78.5% to 82.0%, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), 50 parts by weight, succinic anhydride 2 After adding 10 parts by weight of acetone and 10 parts by weight of acetone and heating at 60 ° C. for 6 hours, the cooling tube was removed to volatilize the acetone, followed by a purification step of eluting unreacted succinic anhydride with 100 parts by weight of acetone. After performing twice, it dried under reduced pressure at 60 degreeC for 5 hours, and obtained the modified polyvinyl alcohol 1 which the succinic acid ester-bonded to the hydroxyl group.

<Example 1>
<(1) Step of preparing a reactive resin composition>
A small pressure vessel with a capacity of 25 L was used for the preparation of the reactive resin composition for the engraving layer. The container has a pressure resistance of 0.5 MPa, a material of SUS304, a double helical ribbon having a blade diameter of 0.32 m as a stirring blade, and the stirring speed is variable from 0 to 200 rpm. In addition, a pressure gauge, a vent valve, a nitrogen valve, and a pressure reducing valve are provided with a cock at the upper part of the pressure vessel, a viewing window is provided, and a material inlet is a bell jar. At the lower part of the pressure vessel, there is a bottom plug valve for extracting the reactive resin composition and a thermocouple for measuring the internal temperature. The reaction vessel has a double structure, the outer tank is used for temperature adjustment with a heating medium, and the inner tank is used for the preparation of the reactive resin composition. Piping is designed so that steam (can be set to a maximum of 150 ° C.), hot water (can be set to a maximum of 95 ° C.), and cooling water at 15 ° C. can be used as the heat medium.

  Release the vent valve of the small pressure vessel, and from the material inlet, "Q-1300" (ammonium N-nitrosophenylhydroxylamine, manufactured by Wako Pure Chemical Industries, Ltd.) 0.62g and 1 ethanol as a polymerization inhibitor After adding .48 kg and 2.49 kg of diethylene glycol as a plasticizer, the stirring blade was rotated at 150 rpm, and then 630 g of hydrophilic polyamide resin 1 and 5.90 kg of modified polyvinyl alcohol 1 were added, followed by stirring for 10 minutes.

  Subsequently, 4.06 kg of pure water was added at a rate of 1 kg / min. At this time, the liquid temperature was 25 ° C.

  Thereafter, the material inlet was tightened with a bell jar with a bolt and nut, and the vent valve was closed to make the pressure vessel a sealed system. For the purpose of preventing powder explosion, after opening the nitrogen valve and pressurizing 0.25 MPa (at this time, the pressure inside the container is 0.35 MPa), the vent valve is opened and the atmospheric pressure (at this time, the pressure inside the container is 0). The pressure in the reaction vessel was replaced with nitrogen by repeating the pressurization of nitrogen at 0.25 MPa and the release of the vent valve. After purging with nitrogen, the vent valve was closed again to make the reaction vessel a sealed system. During this time, the stirring blade continued to stir at 150 rpm.

  Open the steam valve of the heating medium, adjust the steam pressure to 0.2 MPa, raise the temperature of the liquid in the reaction vessel to 105 ° C., and then adjust the steam pressure to 0.15 MPa for 30 minutes. And the polymer was steam-dissolved. At this time, the liquid temperature in the reaction vessel was 110 ° C., and the internal pressure was 0.38 MPa.

  Thereafter, the steam valve is closed, the hot water valve connected to the 75 ° C. hot water tank is opened, hot water is circulated in the outer tank of the reaction vessel with the hot water pump, and the heat medium is switched from steam to 75 ° C. hot water. Polymer dissolution was performed for a minute. At this time, the internal temperature of the reaction vessel was 75 ° C., and the internal pressure was 0.16 MPa.

  After opening the vent valve and returning the internal pressure of the container to atmospheric pressure (0.10 MPa), remove the bell jar from the material charging port, and remove “Blemmer” G (glycidyl methacrylate, manufactured by NOF Corporation) from the material charging port. 374 g was added.

  Next, the pressure inlet was returned to the sealed system by bolting and nut-tightening the material inlet with a bell jar and closing the vent valve. In this state, the mixture was stirred for 30 minutes, the epoxy group of “Blemmer” G and a part of the carboxyl group of the modified polyvinyl alcohol were subjected to an addition reaction, and the polymer side chain was modified with a methacryl group. At this time, the internal temperature of the reaction vessel was 75 ° C., and the internal pressure was 0.10 MPa.

  The vent valve was opened again, the bell jar at the material inlet was removed, and 623 g of “Blenmer” GMR (methacrylic acid adduct of glycidyl methacrylate, manufactured by Nippon Oil & Fats Co., Ltd.) as an ethylenically unsaturated monomer was removed from the material inlet. Epoxy ester “70PA (acrylic acid adduct of propylene glycol diglycidyl ether, manufactured by Kyoeisha Chemical Co., Ltd.)” 623 g, “Blenmer PE” 200 (polyethylene glycol methacrylate having an average molecular weight of 200, manufactured by Nippon Oil & Fats Co., Ltd.) .87 kg, 12.5 g of “Irgacure” 651 (benzyldimethyl ketal, manufactured by Ciba Geigy) and 187 g of “Irgacure” 184 (α-hydroxyketone, manufactured by Ciba Geigy) as a photopolymerization initiator Added.

  Next, the pressure inlet was returned to the sealed system by bolting and nut-tightening the material inlet with a bell jar and closing the vent valve. In this state, the mixture was stirred for 30 minutes to complete the mixing of the reactive resin composition. At this time, the internal temperature of the reaction vessel was 75 ° C., and the internal pressure was 0.10 MPa.

  Thereafter, the rotation speed of the stirring blade was set to 40 rpm, the pressure reducing valve was gradually opened, and vacuum degassing and concentration were performed. The pressure reducing valve is connected to the aspirator via a concentration cooling pipe and a concentrated liquid collection pipe. The concentration cooling pipe is a double pipe, and 15 ° C. cooling water is circulated in the outer pipe.

  After starting the aspirator, the pressure reducing valve was gradually opened, and defoaming was performed while adjusting the degree of vacuum so that the liquid level of the reactive resin composition did not rise to the upper wall surface of the reaction vessel. Defoaming was almost completed when the internal pressure of the pressure vessel was 0.05 MPa, and the liquid of the reactive resin composition began to boil. Therefore, the rotation of the stirring blade was stopped to prevent entrainment of bubbles due to stirring. The vapor of the solvent cooled in the condensing condenser was accumulated in the condensate collecting pipe, and the concentration was continued until 330 mL was distilled off. Then, the pressure reducing valve was closed and the aspirator was stopped. At this time, the internal pressure of the pressure vessel was 0.03 MPa, and the liquid temperature of the reactive resin composition was 65 ° C. The distilled liquid was recovered and its weight was measured to be 265 g. The breakdown is estimated to be a 9: 1 mixture of ethanol and water from the specific gravity of the distillate.

  Next, the vent valve was opened to return the internal pressure to atmospheric pressure (0.10 MPa), and then pressurized to 0.40 MPa with nitrogen. Thereafter, the temperature of the hot water used as the heating medium of the pressure vessel was changed from 75 ° C. to 70 ° C., and the reactive resin composition was stored under these conditions.

<Evaluation of thermal stability of reactive resin composition>
The thermal stability of the reactive resin composition was evaluated by measuring the viscosity immediately after completion of concentration (within 2 hours) and after storage for 24 hours, and evaluating the change in viscosity. The viscosity at 1 hour after concentration was 8.0 Pa · s, and the viscosity after storage for 24 hours was 7.8 Pa · s, showing no increase in viscosity and confirming good thermal stability.

  The sample solution for evaluation was extracted by opening the bottom plug valve at the bottom of the reaction vessel and discharging about 500 g in consideration of the amount of pipe residence, and then collecting about 50 g.

  For the viscosity measurement, a viscometer rheomat 115 (manufactured by Contrabass) was used, and the evaluation liquid was poured into a cylinder having an inner diameter (diameter) of 30.5 mm, and kept at 70 ° C. in a thermostatic chamber with an automatic temperature controller (manufactured by Yurabo) . The rotor has a rotor diameter (diameter) of 12 mm. 3 and a scale setting of 10 (shear rate 32.1 [1 / s]). After the evaluation liquid was injected, the rotor was rotated at a scale setting of 5 (shear rate 5.4 [1 / s]), and after 30 minutes had elapsed, the liquid temperature was stabilized, and then the scale setting was 10 (shear rate). Was set to 32.1 [1 / s]), and the value at the time when 1 minute had passed was read to calculate the viscosity.

<(2) Step of Casting Reactive Resin Composition on Mold Release>
<Preparation of mold release 1>
A primer layer solution was prepared by dissolving 4.9 parts by weight of tetra (n-propoxy) silane and 0.1 part by weight of tetra (n-butoxy) titanium in 45 parts by weight of toluene and 50 parts by weight of xylene. A SUS304 plate having a thickness of 1 mm, a width of 55 cm, and a length of 65 cm was wiped with acetone, and then the primer layer solution was applied onto the SUS plate so as to have a dry film thickness of 0.5 μm to 1.5 μm. Dry at 2 ° C. for 2 hours.

  Next, “PRX306 DISPERSION CLEAR” (silicone rubber solution for release agent, manufactured by Toray Dow Corning Co., Ltd.) was applied on the applied primer layer so as to have a dry film thickness of 50 μm to 90 μm, and at 30 ° C. for 2 hours. Then, it was dried at 80 ° C. for 2 hours and further at 100 ° C. for 4 hours to produce a mold release 1. The structure of the release body is a three-layer structure of SUS304 / primer layer / silicone rubber layer, and the silicone rubber layer side functions as a release body.

<Discharge of reactive resin composition from base>
A coat hanger die having a discharge width of 45 cm was used as a die for discharging the reactive resin composition. The discharge ports were arranged vertically downward, and the clearance of the discharge ports was adjusted so as to be 400 μm ± 20 μm in total width. The inlet of the reactive resin composition was provided on the top of the coat hanger die and connected with a liquid feed line and a flexible hose. The liquid supply system from the pressure vessel, which is a storage container for the reactive resin composition, to the coat hanger die is sequentially the bottom plug valve of the pressure vessel, the liquid supply line, the gear pump for liquid supply, the liquid supply line, the filter unit, the liquid supply Lines, flexible hoses, and coat hanger die inlets are formed in series. In addition, pressure gauges were installed at the inlet and outlet of the filter unit to monitor the pressure in and out of the filter.

  The liquid feed line, filter unit, flexible hose, and coat hanger die have the same heat medium, in this case, the structure that can pass hot water of 70 ° C in order to make the storage temperature of the reactive resin composition constant. ing. The liquid feeding line and the flexible hose are double pipes, and have a structure in which a heat medium passes through the outer pipe and a reactive resin composition passes through the inner pipe. The same applies to the filter housing of the filter unit. The filter unit has a bleed port for bleeding out the reactive resin composition, an air valve for extracting air, a filter body, and a filter housing for setting the filter, and a material epoxy having a 50 μm cut performance as the filter body. A cell pole filter (manufactured by Nippon Pole Co., Ltd.) was used. A gear pump having a pumping capacity of 7.2 cc per rotation was used, and the side clearance of the gear pump was adjusted to 20 μm to 25 μm for the purpose of preventing a thermal reaction due to the occurrence of shear in the gear pump. The rotation speed of the gear pump is variable in the range of 0 to 55 rpm and is driven by an explosion-proof motor.

  A belt conveyor was provided at the lower part of the coat hanger die, the release body 1 was placed on the speed controlled belt conveyor, and the reactive resin composition discharged from the coat hanger die was cast on the release body 1. Since the liquid feed rate by the gear pump was set to 212 cc / min and the line speed of the belt conveyor was set to 40 cm / min, the wet film thickness discharged from the coat hanger die with a discharge width of 45 cm and cast on the mold release was calculated. 212 cc / (40 cm * 45 cm) = 0.178 cm = 1178 μm.

<(3) Step of drying the casting film and separating from the mold release to form an independent sheet>
The mold release body coated with the casting film obtained in the step (2) was dried in a hot air oven at 65 ° C. for 32 minutes and then placed in a room controlled at 20 ° C. relative humidity of 65% for 18 minutes to cool. The casting film was peeled off from the mold release body, and an independent sheet could be formed.

<Measurement of sheet strength>
In order to evaluate whether the obtained sheet is an independent sheet, that is, whether the peeled sheet does not break during handling, the sheet strength was measured.

  The sheet was punched into a shape having a measurement width of 5.0 mm by using a dumbbell described in JIS K 62533 and clamped in a vise to produce a measurement sample. When the film thickness of the sheet having a measurement width of 5.0 mm at this time was measured, it was 960 μm.

  A spring-type balance (maximum 1 kg, minimum scale 10 g) manufactured by Sanko Keiki Co., Ltd. was prepared, the upper part of the spring-type balance was fixed, and the above measurement sample was placed on the lower hook part of the Rivic Tape No. It was pasted with 401 (Nitto Denko Corporation). When the measurement sample was pulled downward at a rate of about 2 to 4 cm / second and the scale when the sheet was broken was read, it was 950 g to 1050 g in five measurements, and the sheet strength was calculated from the average value of 10 N / cm. .

<Measurement of residual solvent ratio of independent sheet>
In order to measure the residual solvent ratio of the obtained sheet, about 1 g of the sheet was weighed into a 30 mL test tube, and the sheet weight was measured to a minimum of 0.1 mg order with a precision balance. Thereafter, 10 mL of the extract was added with a whole pipette, the test tube was covered with a stopcock, and the periphery of the stopcock was sealed with a seal tape. The sealed test tube was heated in a 70 ° C. water bath for 8 hours, and the residual solvent in the sheet was extracted into the extract. The extract was a mixed solvent of n-butanol: 995 parts by weight and iso-butanol: 5 parts by weight, and a mixture added with molecular sieves for the purpose of removing water. Using iso-butanol as an internal standard, a calibration curve was measured in advance with respect to the addition amount of water and ethanol and the peak ratio.

  2.5 μL was extracted from the extract with a microcylinder and injected into a gas chromatograph analyzer 1020 GC Plus / Auto System XL (manufactured by Perkin Elmer) to measure the residual water content and the residual ethanol rate. The residual solvent ratio was calculated from the weighed weight of the sheet, the calibration curve, and the detection peak ratio. The residual solvent ratio of the sheet was a residual moisture ratio of 10% and a residual ethanol ratio of 8.5%.

<(3 ′) Step of volatilizing solvent from independent sheet>
The obtained independent sheet was hung in a hot air oven at 57 ° C., and both sides of the sheet were dried for 120 minutes. The sheet strength of the sheet was measured by the same method as described above except that the spring-type balance was changed to a spring-type balance (maximum 2 kg, minimum scale 20 g) manufactured by Sanko Keiki Co., Ltd. No sheet breakage occurred even at a certain 2.0 kg (sheet strength was 39 N / cm or more). The thickness of the measurement sample at this time was 880 μm. When the residual solvent ratio of the sheet was measured, the residual water ratio was 2.0% and the residual ethanol ratio was less than 0.1%.

<Measurement of sheet shrinkage>
In step (3), immediately before the casting film was peeled off from the mold, marking was performed on the film at intervals of 40 cm in the flow direction and the transverse direction. Thereafter, the sheet was peeled off from the release body, and the interval between the markings was measured on the sheet that had undergone the step (3 ′). As a result, the flow direction and the transverse direction were both 37.5 cm. From this, it was found that the sheet contracted by 6.25% by solvent drying.

<(4) Step of laminating sheet and support coated with adhesive layer>
Using a nip laminator that can nip two rolls, the sheet obtained in (3 ′) above and the support 1 coated with the adhesive layer were laminated. The upper roll of the nip laminator is a rubber roll, and can be moved up and down with compressed air to open the nip and nip. The lower roll was a metal roll that could be heated and heated to 110 ° C. The lower roll is a drive roll. By adjusting the clearance between the upper and lower rolls to the pushing side, once the material is nipped, the automatically nipped material is self-propelled. In this example, the clearance between the upper and lower rolls was adjusted to approximately 400 μm, but the total thickness of the support 1 coated with the adhesive layer was 235 μm, and the average thickness of the sheet obtained in (3 ′) was 880 μm. The total thickness is approximately 1115 μm, and the indented thickness to be nipped is approximately 715 μm.

  The support 1 coated with the adhesive layer was supplied along the lower roll so that the support side was in contact with the lower roll. The sheet was applied so that one side of ethylene glycol was applied and the coated surface was on the lower roll side for supplying the support. First, in a state where the nip is open, the ethylene glycol coating surface at the front end of the sheet is temporarily attached to the adhesive layer surface on the lower roll. After the temporary attachment surface is placed between the nip rolls, a nip is performed and the lower roll is driven by the nip pressure. The nip was automatically fed. In the obtained nip, the sheet and the support were firmly bonded, and it was difficult to peel the sheet from the support.

<(5) Step of laminating sheet and temporary support>
For laminating the sheet and the temporary support, a calender laminator having two metal rolls is used, and before and after the laminator, the sheet is supplied at a constant speed (1.0 m / min in this embodiment). A front conveyor and a rear conveyor for conveying the laminate at a constant speed (1.0 m / min in this example) were installed. The upper roll of the laminator is a roll that can be heated (82 ° C. in this embodiment), and the lower roll can be moved up and down by compressed air. In addition, since the clearance between the metal rolls determines the product thickness, the metal roll having a high roundness is used in both the upper and lower sides, and the clearance is precisely adjusted in the roll width direction. The radius of the metal roll used in this example is 12 mm, and the radius blur accuracy is within 10 μm. The roll clearance was adjusted to 1360 μm ± 5 μm.

  From the front conveyor side, 100 μm thick and 500 mm wide “Lumirror” # 100S10 (polyester film, manufactured by Toray Industries, Inc.) is unwound and placed on the front conveyor. Through the top, the underfilm was used to transport the laminate.

  “Lumirror” # 100S10 with a thickness of 100 μm and a width of 500 mm as a temporary support is supplied to the upper roll side of the calender rolls, passed between the calender rolls, passed to the rear conveyor, and then an under film on the rear conveyor. Affixed with Livic tape. The under film is used as a carrier film that transmits the power of the conveyor to the support on which the adhesive layer is applied, and is removed after the process, and does not become a constituent of the flexographic printing plate precursor.

  The laminate of the sheet and the support obtained in step (4) is attached to the under film on the front conveyor with cello tape (registered trademark) so that the support is on the under film side. An appropriate amount of the reactive resin composition prepared in (1) was cast.

  Thereafter, the under film and the temporary support were manually pressed onto the rear conveyor, the drive of the rear conveyor was transmitted to the under film and the temporary support, and pulled from the front conveyor side to the rear conveyor side. When the cast reactive resin composition passes through the calendar roll, an amount exceeding the clearance of the calendar roll is automatically scraped to both ends in the transverse direction and to the front conveyor side in the flow direction. After passing through the calendar roll, a laminate having a thickness controlled by the clearance of the calendar roll is completed.

  The composition of the obtained laminate is, in order, an under film, a support, an adhesive layer, a sheet obtained in (3 ′), a cast reactive resin composition, and a temporary support coated with a slip coat layer. Is the body. Of these, the under film and the support are both polyester films and are not bonded. The cast reactive resin composition impregnates the sheet obtained in (3 ′) with the solvent contained over time, and is integrated with the sheet obtained in (3 ′) to form an engraving layer. .

  After the laminate is stored for a day, the four sides of the laminate (the sheet and the adhesive layer support are not present and the portion where the reactive resin composition occupies most) are cut, and the support / adhesive layer / engraving layer / temporary A laminate of the support was obtained. Furthermore, both sides of each side were cut off by 2 cm or more to obtain a laminate having a plate size of 36 cm × 50 cm. The sheet obtained in (3 ′) and the cast reactive resin composition have the same composition, and the solvent in the cast reactive resin composition diffuses and moves to the sheet obtained in (3 ′). It becomes a sculpture layer.

<(6) Step of crosslinking the engraving layer>
Using the batch type plate-making machine “GPP500” (manufactured by Toray Industries, Inc.) equipped with a high-intensity chemical lamp “TLK-40W10R” (manufactured by Phillips), the laminated body obtained above was subjected to UVA from the temporary support side. The engraving layer was photocrosslinked by exposure corresponding to an integrated light quantity of 2000 mJ / cm ² to obtain a flexographic printing plate precursor 1 for laser engraving.

<Evaluation of plate thickness accuracy of original plate>
After the flexographic printing plate precursor 1 for laser engraving was cut into 2 cm square pieces, the temporary support was peeled off, and the thickness of each of the piece pieces was measured. The plate thickness was 1.13 mm to 1.15 mm. The range was stable at 0.02 mm.

<Comparative Example 1>
<(1) Step of preparing reactive resin composition> is performed in the same manner as in Example 1. <(2) Step of casting reactive resin composition on mold release> to <(4) Adhering to sheet The step of laminating the support coated with the layer was changed to the following <process of directly casting the reactive resin composition on the support coated with the adhesive layer and drying>.

<The process of casting a reactive resin composition directly on the support body with which the contact bonding layer was apply | coated, and drying>
<Discharge of the reactive resin composition from the die> is a method in which a support 1 coated with an adhesive layer is placed on a belt conveyor whose speed is controlled so that the adhesive layer is on the upper surface and discharged from a coat hanger die. The same reactive resin composition as described in Example 1 was used except that the reactive resin composition was cast on the support 1 coated with the adhesive layer.

  The reactive resin composition cast on the support 1 coated with the adhesive layer is dried in a hot air oven at 65 ° C. for 32 minutes, and then placed in a room controlled at 20 ° C. and 65% relative humidity for 18 minutes to cool. did. Further, drying was performed in a hot air oven at 57 ° C. for 120 minutes.

  The difference from Example 1 was that the final drying in a hot air oven at 57 ° C. was performed not on both sides but on one side with one side covered with a support, and a reactive resin was used during the drying process. That is, the engraving layer made of the composition and the support coated with the adhesive layer were applied and adhered.

  The resulting engraved layer / adhesive layer / support laminate had significant curl on the engraved layer side. This is because the engraving layer made of the reactive resin composition shrinks in size by drying of the solvent, and in Example 1, it shrinks by 6.25%, whereas the support is dimensionally stable and shrinkage is 0%. It was caused by the shrinkage difference. On the other hand, in Example 1, since the sheet which was dried and contracted in the state of an independent sheet was laminated with <(4) the support on which the adhesive layer was applied>, such curling did not occur. .

<Measurement of residual solvent ratio of engraving layer>
The engraved layer was sampled from the laminate thus obtained, and the residual solvent rate of the engraved layer was measured by the same method as in Example 1. As a result, the residual moisture content was 4.0% and the residual ethanol rate was 0.5. %Met. It can be seen that Comparative Example 1 with single-sided drying has lower drying efficiency than Example 1 where double-sided drying was performed.

<(6) Step of crosslinking the engraving layer>
Using the batch type plate-making machine “GPP500” (manufactured by Toray Industries, Inc.) equipped with a high-intensity chemical lamp “TLK-40W10R” (manufactured by Phillips), the laminated body obtained above was subjected to UVA from the temporary support side. and the cumulative amount of light 2000 mJ / cm ² equivalent exposure photocrosslinked the engraving layer to obtain a flexographic printing plate precursor for laser engraving 2.

<Evaluation of plate thickness accuracy of original plate>
When the flexographic printing plate precursor 2 for laser engraving was cut into 2 cm square pieces and the thicknesses of the piece pieces were measured, the plate thickness was 1.08 mm to 1.15 mm and the plate thickness accuracy was 0.07 mm. It was bad.

<Comparative example 2>
In Comparative Example 1, between <the step of casting the reactive resin composition directly on the support coated with the adhesive layer and drying> and <(6) the step of crosslinking the engraving layer><(5) Step of laminating a sheet and a temporary support> described in 1. was performed to obtain a laser engraving flexographic printing plate precursor 3.

<Evaluation of plate thickness accuracy of original plate>
The flexographic printing plate precursor 3 for laser engraving was cut into 2 cm square pieces, and the thicknesses of the cut piece samples were measured. As a result, the plate thickness was 1.12 mm to 1.15 mm and the range was 0.03 mm. Compared to, the plate thickness accuracy was slightly worse. This is presumed that the residual solvent ratio in the engraving layer was higher than that in Example 1 and affected the film thickness accuracy. Unlike Example 1, the original plate 3 after the temporary support was peeled had a problem of large curl and difficulty in handling.

  The present invention can be used for producing a flexographic printing plate precursor for laser engraving. It can also be applied to the production of letterpress printing plates for laser engraving, intaglio printing plates for laser engraving, and stencil printing plates for laser engraving.

11: Reactive resin composition storage container 12: Liquid feed line 13: Fluid carrier 14: Die 21: Mold release body 22: Casting film 23: Conveyor belt 31: Drying means 32: Independent sheet (engraved layer sheet)
41: Nip roll 42: Support 43 coated with adhesive layer 43: Sheet / adhesive layer / support laminate 51: Calendar roll 52: Temporary support 53: Cast reactive resin composition 54: Engraving layer

Claims (5)

(1) a step of preparing a reactive resin composition;
(2) a step of casting the reactive resin composition on the mold release body,
(3) a step of drying the casting film and peeling it from the release body to form an independent sheet;
A method for producing a flexographic printing plate precursor for laser engraving comprising at least (4) The method for producing a flexographic printing plate precursor for laser engraving according to claim 1, further comprising a step of laminating the sheet and the support coated with the adhesive layer. 3. The method for producing a flexographic printing plate precursor for laser engraving according to claim 2, wherein the adhesive layer applied on the support contains the same or the same polymer as in the reactive resin composition. (5) The method for producing a flexographic printing plate precursor for laser engraving according to claim 1, further comprising a step of laminating the sheet and the temporary support. The method for producing a flexographic printing plate precursor for laser engraving according to claim 4, wherein the temporary support has a layer containing the same or the same kind of polymer as in the reactive resin composition.

Images