JP2010076243A - Method for manufacturing cylindrical original plate for printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a cylindrical original plate for printing with a high thickness accuracy, a high adhesive strength, and furthermore a high productivity. <P>SOLUTION: The method for the cylindrical original plate for printing includes: (1) the process for preparing an original printing plate layer sheet having an uncured curable resin composition layer; (2) the process for processing both ends of the original printing plate layer sheet: (2-a) the process for removing a part of an upper surface of the curable resin composition layer of an overlapping margin part on a starting end side for winding; (2-b) the process for removing a part of the lower surface of the curable resin composition layer of an overlapping margin part on a terminal end side for winding; (2-c) the process for forming a light absorbing layer for absorbing a light with a specific wavelength; (2-d) the process for irradiating the light absorbing layer with a laser light with a wavelength absorbed by the light absorbing layer; (3) the process for piling up the overlapping margin on the starting end side for winding and the overlapping margin on the terminal end side for winding; (4) the process for irradiating the light absorbing layer of the piled-up part with a laser light with a wavelength absorbed by the light absorbing layer; and (5) the process for curing the uncured curable resin composition layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a cylindrical printing original plate on which a pattern is formed.

  In recent years, when a resin relief printing plate such as flexographic printing, dry offset printing, letter press printing or surface processing such as embossing is applied, the resin in the irradiated portion is removed by irradiating the resin layer with laser light. Therefore, a laser engraving method for forming a concavo-convex pattern on the surface has come to be used. Examples of the resin layer material applied to the laser engraving method include vulcanized rubber, a cured photosensitive resin obtained by photocuring a photosensitive resin composition, and a cured thermosetting resin composition by heat treatment. It is used. In particular, in recent years, from the viewpoint of shortening the processing time, a technique for laser engraving a photosensitive resin cured product obtained by photocuring a photosensitive resin composition has increased.

  In Patent Document 1 (Japanese Patent No. 2846954), a continuous printing element is manufactured by winding a sheet-like printing original layer (sheet element) around a printing sleeve or a printing cylinder and fusing the ends. It is described.

Japanese Patent No. 2846954

  The manufacturing method of the cylindrical printing original plate which winds the printing original layer sheet on the cylindrical support as disclosed in Patent Document 1 is simple, and the cylindrical printing original plate can be manufactured with high productivity. However, in the cylindrical printing original plate manufactured in this way, the joint strength between the winding start end and the winding end joint portion of the printing original layer sheet is weak, for example, a pattern is formed while rotating the cylindrical printing original plate at a high speed. When laser engraving is applied or high-speed printing is performed, the printing original plate layer or the printing plate layer may be detached from the support.

  Therefore, in the present invention, by a manufacturing method in which a printing original layer sheet is wound around a cylindrical support, laser engraving is applied, and even when high-speed printing is performed, the printing original layer or the printing plate layer does not come off. It is an object to produce a cylindrical printing original plate having a high bonding strength.

As a result of intensive studies on the above problems, it has been found that if the winding start and end of the printing original layer sheet are overlapped and welded together, the joint strength of the seam is significantly improved.
However, in that case, a portion where the printing original layer overlaps and a portion where the printing original layer overlaps are formed, and the thickness of the printing original layer becomes slightly uneven depending on the location. It has been found that printing unevenness is caused even by such slight unevenness of the thickness of the printing original plate layer.
Based on the above knowledge, when winding the printing original plate layer sheet around the cylindrical support, while winding and welding so that the winding start and end of the sheet overlap, by preliminarily thin the overlap allowance, The present inventors have found that the above problems can be solved without causing adverse effects such as printing unevenness, and have completed the present invention.

The present invention is as follows.
A method for producing a cylindrical printing original plate by winding a printing original layer sheet around a cylindrical support, comprising the following steps (1) to (5);
(1) preparing a printing original plate layer sheet having an uncured curable resin composition layer;
(2) Process of processing both ends of the printing original plate layer sheet including the following steps (2-a) to (2-d):
(2-a) a step of partially removing the upper surface of the curable resin composition layer of the overlapping margin portion on the side to be a winding start end when the printing original plate layer sheet is wound around the cylindrical support;
(2-b) a step of partially removing the lower surface of the curable resin composition layer of the overlap margin portion on the side to be the winding end when the printing original plate layer sheet is wound around the cylindrical support;
(2-c) The light absorption which absorbs the light of a specific wavelength on the upper surface of the curable resin composition layer of the overlap margin part by the side made into the winding start end which removed the upper surface partially in the process (2-a) Forming a layer;
(2-d) a step of irradiating the light absorption layer formed in step (2-c) with laser light having a wavelength that is absorbed by the light absorption layer;
(3) A step of winding the printing original layer sheet around a cylindrical support and superimposing the overlapping margin on the winding start end side and the overlapping margin on the winding end side;
(4) A step of irradiating a portion of the light absorption layer superposed in step (3) with laser light having a wavelength that is absorbed by the light absorption layer;
(5) A step of curing the uncured curable resin composition layer.

  ADVANTAGE OF THE INVENTION According to this invention, the cylindrical printing original plate with high joining strength of an edge part and no printing unevenness can be manufactured with high productivity.

Hereinafter, preferred embodiments of the present invention will be described in more detail. The present invention is a method for producing a cylindrical printing original plate in which a printing original plate layer sheet is wound around a cylindrical support, and particularly has a feature in a processing method in a connecting step at both ends of the printing original layer sheet. The treatment of both end portions of the printing original layer sheet is extremely important from the viewpoint of securing the joint strength of the joint portion. In particular, in a laser engraving process or printing process, a cylindrical printing original plate or a cylindrical printing plate is used after being rotated at a high speed. Therefore, if the seam part is removed during these processes, an extremely expensive laser engraving machine or There is a possibility of damaging the printing press.
Also, ensuring the thickness accuracy of the seam is important for ensuring good print quality. In the present invention, joining of both ends of the printing original plate layer sheet is performed by laser welding, so that the joining strength of the seam portion is ensured, and the thickness accuracy of the seam portion is also high by preliminarily reducing the overlap allowance. Can be secured.

[Step (1)]
In the step (1), a printing original layer sheet for forming a printing original layer of the cylindrical printing original is prepared. The printing original plate layer sheet only needs to have at least an uncured curable resin composition layer, may be an uncured curable resin composition layer alone, or may be uncured on a substrate sheet. A laminate of curable resin composition layers may be used.

[Step (2)]
Step (2) is a processing step for both ends of the printing original plate layer sheet, including steps (2-a) to (2-d). Steps (2-a), (2-c), and (2-d) need to be performed in this order, but step (2-b) should be performed at any point during step (2). Can do.
In the steps (2-a) and (2-b), a part of the surface of the cured resin composition layer, which is an overlap margin when the printing original plate layer sheet is wound around the cylindrical support, is removed. The width of the overlapped portion is preferably 1 mm or more and 50 mm or less, more preferably 3 mm or more and 10 mm or less, and further preferably 3 mm or more and 5 mm or less. When the width of the overlapping portion is within the above range, the bonding strength of the bonded portion can be ensured.

  The removal of the surface of the cured resin composition layer is performed so that the total thickness of the overlap allowance and the light absorption layer when the overlap allowance is overlapped is the same as the thickness of the printing original plate layer sheet or 0.5 mm or less. . More preferably, the thickness is 0.2 mm or less, and further preferably 0.1 mm or less. By doing so, it is possible to minimize the influence on the printing of the thickness of the overlapping portion of the overlapping margin.

  The surface of the cured resin composition layer to be partially removed is the upper surface for the overlap margin portion on the winding start end side and the lower surface for the overlap margin portion on the winding end side. Here, the upper surface means a surface on the outer side when wound on the cylindrical support, and the lower surface means a surface in contact with the cylindrical support when wound on the cylindrical support.

In order to manage the thickness accuracy of the printing original plate layer, it is important to ensure the processing dimension accuracy in the step (2-a) and the step (2-b). From the viewpoint of securing processing dimensional accuracy, in the step (2-a) and / or (2-b), partial removal of the surface of the cured resin composition layer is performed by fixing the end of the printing original plate layer sheet. Is preferred.
The method of fixing the end of the printing original layer sheet is preferably a method of adsorbing in a reduced pressure state, and the method of adsorbing in the reduced pressure state is the end of the sheet-like resin on the adsorption jig having a porous body on the surface. The method is preferably a method in which the parts are brought into contact and sucked through the porous body under reduced pressure. As a material of the adsorption jig, ceramics and metals are preferable from the viewpoints of dimensional stability and surface processing accuracy.

  Further, from the viewpoint of ensuring processing dimensional accuracy, in the step (2-a) and / or (2-b), a part of the surface of the curable resin composition layer is removed, and the curable resin composition layer is formed into a sheet. It is preferable to carry out by cutting with a blade in a direction parallel to and perpendicular to, or by cutting or grinding. Furthermore, it is preferable to remove a part of the surface while cooling the curable resin composition layer to −50 ° C. or more and 10 ° C. or less. By cooling, it becomes possible to improve the processing accuracy of the end portion. Examples of the cooling method include an electronic cooling method using a Peltier element or the like, a jig cooling method by circulating a refrigerant, and a method of injecting cold air to a processing part.

  Furthermore, in order to prevent the curable resin composition layer from being deformed when the steps (2-a) and / or (2-b) are performed, the steps (2-a) and / or (2) are performed. Prior to -b), a portion other than the overlapping portion of the curable resin composition layer may be cured.

In the step (2-c), light having a specific wavelength is absorbed on the upper surface of the curable resin composition layer of the overlapping margin portion on the side to be the winding start end from which the upper surface has been partially removed in the step (2-a). A light absorption layer is formed.
The thickness of the light absorption layer is preferably 10 μm or more and 500 μm or less. More preferably, they are 50 micrometers or more and 300 micrometers or less, More preferably, they are 80 micrometers or more and 200 micrometers or less. The light absorption layer may contain the same resin as that contained in the curable resin composition constituting the curable resin composition layer. The light absorbing layer may contain a dye or pigment that absorbs light of a specific wavelength. Dyes and pigments that absorb light of a specific wavelength are not particularly limited, but black pigments such as carbon black, graphite, activated carbon, carbon nanotubes, fullerene, metal oxide pigments such as iron oxide and copper oxide, phthalocyanine series And organic pigments and dyes such as azo, perinone, and anthraquinone.

  There is no limitation on the method for forming the laser absorption layer. For example, a liquid resin composition may be applied, or a film previously formed into a film shape may be laminated. In order to convert light energy of a specific wavelength into heat and weld the light absorption layer and the curable resin layer, the material constituting the light absorption layer is preferably a material having thermoplasticity. Furthermore, it is more preferable that the material is cured, for example, thermally cured by some means during or after welding.

In step (2-d), the light absorption layer formed in step (2-c) is irradiated with laser light having a wavelength that is absorbed by the light absorption layer. By irradiation with laser light in the step (2-d), the light absorption layer can be melted and the light absorption layer and the curable resin composition layer can be welded.
The light source of the laser beam used in the step (2-d) is not particularly limited, but the light absorption layer is melted and converted to heat sufficient to weld the light absorption layer and the curable resin composition layer. For this purpose, a near infrared or infrared laser having a wavelength of 700 nm or more is preferable. Among these, a laser in the near infrared region having a wavelength of 3 μm or less, which is a wavelength at which the curable resin composition does not have light absorption properties, is preferable. Specific examples of the laser light source include a semiconductor laser, a YAG laser, a YVO ₄ laser, a YLF laser, a fiber laser doped with Er or Yb, a Ti sapphire laser, and an Alexandrite laser.
The laser may be a continuous wave laser or a pulsed laser. The average output is preferably 0.1 W or more and 200 W or less. A more preferable range is 0.5 W or more and 100 W or less, and further preferably 1 W or more and 100 W or less. The pulsed laser has a large peak output even if the average output is relatively small, and is suitable for welding the light absorption layer and the curable resin composition layer. It is preferable that the half-width of the pulse time of the pulsed laser is 1 nanosecond or more and 50 milliseconds or less. More preferably, it is 10 nanoseconds or more and 1 millisecond or less, More preferably, it is 50 nanoseconds or more and 50 microseconds or less. If the half-time width is in the above range, it can be sufficiently used for welding without using a high-power laser. The oscillation frequency of the pulsed laser is preferably 1 kHz or more and 500 MHz or less. A more preferable range is 10 kHz or more and 100 MHz or less. Within this frequency range, a pulse having a sufficiently high peak output can be used for welding. The laser beam diameter irradiated on the interface between the light absorbing layer and the curable resin layer is preferably 10 μm or more and 2 mm or less. A more preferable range is 0.1 mm or more and 1 mm or less. The laser beam can be narrowed down to a small diameter using a condenser lens.

In the step (2-d), it is preferable that the light absorption layer is irradiated with laser light from the curable resin composition layer side. At this time, it is preferable that the curable resin composition layer and the light absorption layer are in close contact with each other. Therefore, it is preferable to apply pressure to both so as not to move while irradiating the laser beam. Therefore, it is preferable to hold down the light absorption layer and the curable resin composition layer with a plate or cylinder made of a material such as glass or plastic that transmits laser light. The applied pressure is preferably 0.05 kgf / cm ² or more and 10 kgf / cm ² or less.

[Steps (3) to (5)]
In the step (3), the printing original layer sheet is wound around the cylindrical support, and the overlapping margin on the winding start end side and the overlapping margin on the winding end side are overlapped. Here, the light absorbing layer comes into contact with the surface from which the surface of the curable resin composition layer at the overlapping margin portion on the winding end side has been partially removed.
Further, in the step (4), the light absorption layer of the overlapped portion in the step (3) is irradiated with laser light having a wavelength that is absorbed by the light absorption layer. Here, as the laser light source, the same laser light source that can be used in the step (2-d) can be used. Moreover, it is preferable to perform irradiation of the laser beam to the light absorption layer from the curable resin composition layer side (outside) of the overlap margin portion on the winding end side.

In the step (5), the uncured curable resin composition layer is cured to form a cylindrical cured product.
In the step (5), when the curable resin composition is a photosensitive resin composition, the light source used for curing the curable resin composition layer includes a high pressure mercury lamp, an ultrahigh pressure mercury lamp, an ultraviolet fluorescent lamp, a germicidal lamp, A carbon arc lamp, a xenon lamp, a metal halide lamp, etc. can be mentioned. The light irradiated to the curable resin composition preferably has light having a wavelength of 200 nm to 300 nm. In particular, when the curable resin composition contains a hydrogen abstraction type photopolymerization initiator (d) described later, since the hydrogen abstraction type photopolymerization initiator (d) often has strong light absorption in this wavelength region, it is 200 nm. From 300 nm to 300 nm, sufficient curability of the surface of the curable resin composition layer can be ensured. The light source used for photocuring may be one type, but the curability of the resin may be improved by curing using two or more types of light sources having different wavelengths, so use two or more types of light sources. There is no problem.
Steps (1) to (5) can be performed in this order.

  An adhesive layer or a pressure-sensitive adhesive layer may be formed on the surface of the cylindrical support. The adhesive layer or the pressure-sensitive adhesive layer preferably contains a photosensitive resin composition, a thermosetting resin composition, an anaerobic curing composition, or a pressure-sensitive curing composition. Among these, a photosensitive resin composition is particularly preferable from the viewpoint of curing speed. It is also preferable to use a pressure-sensitive adhesive or pressure-sensitive adhesive of the type that contains a microcapsule containing a curing agent inside and breaks the microcapsule when pressurized and the curing agent is ejected from the inside.

[Cylindrical support]
Examples of the cylindrical support include a metal, rubber, or plastic cylinder, and a plastic, metal, or fiber reinforced plastic sleeve. From the viewpoint of handling and weight, a hollow cylindrical support made of fiber reinforced plastic is particularly preferable. The fiber reinforced plastic preferably contains at least one kind of fiber selected from glass fiber, polyamide fiber, polyimide fiber, polyester fiber, polyurethane fiber, cellulose fiber, carbon fiber, metal fiber, and ceramic fiber.

  When the cylindrical support is a hollow cylindrical support, the thickness is preferably 0.2 mm or more and 2 mm or less. More preferably, it is 0.3 mm or more and 1.5 mm or less, More preferably, it is 0.4 mm or more and 0.8 mm or less. If the thickness is within the above range, it is easy to attach to the air cylinder, and sufficient mechanical strength can be ensured without breaking or cracking.

[Print original layer sheet]
In the present invention, the printing original plate layer sheet has at least an uncured curable resin composition layer. Here, the curable resin composition constituting the curable resin composition layer refers to a resin or a resin composition that is cured by some means.
Examples of the curable resin composition include a photosensitive resin composition and a thermosetting resin composition. The uncured curable resin composition preferably exhibits thermoplasticity.
The curable resin composition preferably contains the resin (b) and the organic compound (c).

The curable resin composition is solid at 20 ° C. To be solid at 20 ° C. means to retain its shape without flowing even if it is kept at a temperature of 20 ° C. for 1 hour or more.
The thickness of the curable resin composition layer is not limited, and can be, for example, 0.1 mm or more and 5 mm or less. When the thickness is within this range, it can be easily wound on a cylindrical support and can be used for printing applications such as flexographic printing, dry offset printing, and gravure printing.

[Resin (b)]
The composition of the resin (b) is not particularly limited. The number average molecular weight is preferably 1000 or more and 300,000 or less, more preferably 2000 or more and 200,000 or less, and further preferably 5000 or more and 150,000 or less. When the number average molecular weight of the resin (b) is 1000 or more, the cured product when the curable resin composition is subsequently cured maintains strength and can withstand repeated use. Moreover, if the soot average molecular weight of resin (b) is 300,000 or less, a sheet-like resin can be produced without excessively increasing the melt viscosity of the curable resin composition during extrusion molding. The upper limit of the number average molecular weight of the resin (b) is preferably 200,000 or less.
The number average molecular weight referred to here is a value measured by gel permeation chromatography, calibrated with polystyrene having a known molecular weight, and converted.

The resin (b) may have a polymerizable unsaturated group in the molecule. A particularly preferred specific example is a polymer having 0.7 or more polymerizable unsaturated groups on average per molecule. An average of 0.7 or more per molecule is preferable because the resulting sheet has excellent mechanical strength and good durability, and can withstand repeated use, particularly as a printing original plate layer and a printing plate layer. Considering the mechanical strength of the printing original plate layer, the polymerizable unsaturated group of the resin (b) is preferably 0.7 or more per molecule, and more preferably more than 1. The upper limit of the number of polymerizable unsaturated groups per molecule is not particularly limited, but is preferably 20 or less. If it is 20 or less, the shrinkage | contraction at the time of photocuring can be suppressed low, and generation | occurrence | production of the crack etc. in the surface vicinity can also be suppressed.
The term “having a polymerizable unsaturated group in the molecule” as used herein means that a polymerizable unsaturated group is directly attached to the end of the polymer main chain, the end of the polymer side chain, the polymer main chain or the side chain. This includes cases where

  Specific examples of the resin (b) include those having the above-mentioned polymerizable unsaturated group with the following polymer as a skeleton. Examples of polymers used as the skeleton include polyolefins such as polyethylene and polypropylene, polydienes such as polybutadiene and polyisoprene, polyhaloolefins such as polyvinyl chloride and polyvinylidene chloride, polystyrene, polyacrylonitrile, polyvinyl alcohol, polyvinyl acetate, and polyvinyl acetal. , Polyacrylic acid, poly (meth) acrylic acid esters, poly (meth) acrylamide, polyester, polycarbonate, polyacetal, polyurethane, polyamide, polyurea, polyimide, etc. One kind or two or more kinds of polymer materials can be used. As a form in the case of using a plurality of polymer materials, either a copolymer or a blend may be used.

In particular, when producing a printing plate capable of forming a flexible relief image as in flexographic printing plate applications, a part of the resin (b) is a liquid resin having a glass transition temperature of 20 ° C. or lower, more preferably a glass transition. A liquid resin having a temperature of 0 ° C. or lower can also be used. Examples of such a liquid resin include hydrocarbons such as polyethylene, polybutadiene, hydrogenated polybutadiene, polyisoprene, and hydrogenated poisoprene, polyesters such as adipate and polycaprolactone, and polymers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Examples include ethers, aliphatic polycarbonates, silicones such as polydimethylsiloxane, polymers of (meth) acrylic acid and / or derivatives thereof, and mixtures and copolymers thereof. In particular, unsaturated polyurethanes having a polycarbonate structure are preferred from the viewpoint of weather resistance.
The content is 30 wt% or more and 100 wt% or less with respect to the entire resin (b).

  As a method for introducing a polymerizable unsaturated group into the resin (b), for example, a compound in which a polymerizable unsaturated group is directly introduced into the molecular end or molecular chain may be used as a monomer. As a compound having a plurality of reactive groups such as hydroxyl group, amino group, epoxy group, carboxyl group, acid anhydride group, ketone group, hydrazine residue, isocyanate group, isothiocyanate group, cyclic carbonate group, ester group, etc. After reacting with a binder having multiple functional groups that can bind to the reactive group (for example, polyisocyanate in the case of a hydroxyl group or an amino group), the molecular weight is adjusted and converted to a terminal binding group. And a compound having a functional group that reacts with the terminal binding group of this compound and a compound having a polymerizable unsaturated group to react with each other to form a polymerizable unsaturated group at the terminal. Methods, such as how to enter can be suitably raised.

  Moreover, when using the cylindrical printing original plate obtained by the manufacturing method of this invention as a printing base material for laser engraving, it is preferable to use resin with high thermal decomposability as resin (b). For example, compounds having α-methylstyrene, methacrylic acid ester, acrylic acid ester, carbonate bond, carbamate bond and the like in the molecule are known as highly thermally decomposable compounds. As an index of thermal decomposability, thermogravimetric data obtained by measuring weight loss when a sample is heated in an inert gas atmosphere can be used. As a preferred resin, the temperature at which the weight is reduced by half is preferably in the range of 150 ° C. or higher and 450 ° C. or lower. A more preferable range is 250 ° C. or higher and 400 ° C. or lower, and further preferably 250 ° C. or higher and 380 ° C. or lower. Also preferred are compounds that undergo thermal decomposition in a narrow temperature range. As the index, in the thermogravimetric analysis, the difference between the temperature at which the weight is reduced to 80% of the initial weight and the temperature at which the weight is reduced to 20% of the initial weight is preferably 100 ° C. or less. More preferably, it is 80 degrees C or less, More preferably, it is 60 degrees C or less.

[Organic compound (c)]
The organic compound (c) is a compound having an unsaturated bond involved in radical polymerization reaction or ring-opening polymerization reaction, and the number average molecular weight is preferably 1000 or less in consideration of easiness of dilution with the resin (b). . Examples of the organic compound (c) include olefins such as ethylene, propylene, styrene and divinylbenzene, acetylenes, (meth) acrylic acid and derivatives thereof, haloolefins, unsaturated nitriles such as acrylonitrile, (meth) acrylamide And derivatives thereof, allyl compounds such as allyl alcohol and allyl isocyanate, unsaturated dicarboxylic acids such as maleic anhydride, maleic acid, fumaric acid and itaconic acid and their derivatives, vinyl acetates, N-vinylpyrrolidone, N-vinylcarbazole , Cyanate esters, and the like, and (meth) acrylic acid and derivatives such as (meth) acrylic acid ester are preferable examples from the viewpoint of the abundance of their types and price.

  Examples of the derivatives include alicyclic compounds having a functional group such as a cycloalkyl group, a bicycloalkyl group, a cycloalkene group, and a bicycloalkene group, and a functional group such as a benzyl group, a phenyl group, a phenoxy group, a methylstyryl group, and a styryl group. Aromatic compounds having alkyl groups, alkyl groups, halogenated alkyl groups, alkoxyalkyl groups, hydroxyalkyl groups, aminoalkyl groups, tetrahydrofurfuryl groups, compounds having functional groups such as glycidyl groups, alkylene glycols, polyoxyalkylene glycols, ( Alkyl / allyloxy) polyalkylene glycol and ester compounds of polyhydric alcohols such as trimethylolpropane.

The organic compound (c) can be selected from one or more types depending on the purpose. For example, in order to suppress swelling of the printing original plate layer (printing plate layer) with respect to the organic solvent in the printing ink such as alcohol or ester, at least a long-chain aliphatic, alicyclic or aromatic derivative is used as the organic compound (c). It is preferable to use one or more types.
In order to increase the mechanical strength of the printing original layer sheet, it is preferable to use at least one compound having an alicyclic or aromatic substituent as the organic compound (c). In this case, the content of the compound having an alicyclic or aromatic substituent is preferably 20 wt% or more and 100 wt% or less, more preferably 50 wt% or more and 100 wt% or less of the total amount of the organic compound (c). is there.

[Photopolymerization initiator]
In the present invention, the curable resin composition may be a photosensitive resin composition, and the curable resin composition layer may be cured by irradiation with light. As light, for example, high-energy rays such as electron rays and X-rays can be used in addition to ultraviolet rays and visible rays. In particular, when photocuring using ultraviolet light or visible light, it is preferable to add a photopolymerization initiator to the curable resin composition. As the photopolymerization initiator, it is preferable to add a hydrogen abstraction type photopolymerization initiator (d) and / or a decay type photopolymerization initiator (e).

  The hydrogen abstraction type photopolymerization initiator (d) is not particularly limited as long as it is a compound capable of generating a radical by extracting hydrogen from the surrounding medium through an excited triplet state. In particular, it is preferable to use an aromatic ketone. For aromatic ketones, an excited triplet state is efficiently obtained by photoexcitation, and this excited triplet state has proposed a chemical reaction mechanism in which hydrogen is extracted from the surrounding medium to generate radicals. The generated radical is considered to be involved in the photocrosslinking reaction. Examples of aromatic ketones include benzophenones, Michler ketones, xanthenes, thioxanthones, and anthraquinones, and it is preferable to use at least one compound selected from these groups. Benzophenones refer to benzophenone or derivatives thereof, and specifically include 3,3 ′, 4,4′-benzophenonetetracarboxylic anhydride, 3,3 ′, 4,4′-tetramethoxybenzophenone, and the like. . Michler ketones refer to Michler ketone and its derivatives. Xanthenes refer to derivatives substituted with xanthene and an alkyl group, phenyl group, or halogen group. Thioxanthones refer to thioxanthone and derivatives substituted with an alkyl group, a phenyl group, and a halogen group, and examples thereof include ethylthioxanthone, methylthioxanthone, and chlorothioxanthone. Anthraquinones are anthraquinone and derivatives substituted with alkyl groups, phenyl groups, halogen groups, and the like.

  The addition amount of the hydrogen abstraction type photopolymerization initiator (d) is desirably 0.3 wt% or more and 10 wt% or less, more preferably 0.5 wt% or more and 5 wt% or less of the total amount of the photosensitive resin composition. If the addition amount is within this range, when the photosensitive resin composition is photocured in the air, the curability of the cured product surface can be sufficiently secured, and no cracks or the like are generated on the surface during long-term storage. It is possible to ensure a fading ability.

The decay type photopolymerization initiator (e) refers to a compound that generates an active radical by generating a cleavage reaction in the molecule after light absorption, and is not particularly limited. Specific examples include benzoin alkyl ethers, 2,2-dialkoxy-2-phenylacetophenones, acetophenones, acyloxime esters, azo compounds, organic sulfur compounds, acylphosphine oxides, diketones, and the like. It is preferable to use at least one compound selected from these groups. Examples of benzoin alkyl ethers include benzoin isopropyl ether and benzoin isobutyl ether. Examples of 2,2-dialkoxy-2-phenylacetophenones include 2,2-dimethoxy-2-phenylacetophenone and 2,2-diethoxy-2-phenylacetophenone. Examples of acetophenones include acetophenone, trichloroacetophenone, 1-hydroxycyclohexylphenylacetophenone, 2,2-diethoxyacetophenone, and the like. Examples of acyl oxime esters include 1-phenyl-1,2-propanedione-2- (o-benzoyl) oxime. Examples of the azo compound include azobisisobutyronitrile, diazonium compound, and tetrazene compound. Examples of diketones include benzyl and methylbenzoyl formate.
The addition amount of the collapsible photopolymerization initiator (e) is preferably 0.3 wt% or more and 10 wt% or less, more preferably 0.5 wt% or more and 5 wt% or less with respect to the entire photosensitive resin composition. It is. If the addition amount is within this range, when the photosensitive resin composition is photocured in the air, the curability inside the cured product can be sufficiently secured.

A compound having a site functioning as a hydrogen abstraction type photopolymerization initiator (d) and a site functioning as a decay type photopolymerization initiator (e) in the same molecule can also be used as the photopolymerization initiator. Specific examples include α-aminoacetophenones. Also, for example, compounds such as 2-methyl-1- (4-methylthiophenyl) -2-morpholino-propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone Can be mentioned.
The addition amount of the photopolymerization initiator having the site functioning as the hydrogen abstraction type photopolymerization initiator (d) and the site functioning as the decay type photopolymerization initiator (e) in the same molecule is the entire photosensitive resin composition. Is preferably 0.3 wt% or more and 10 wt% or less, more preferably 0.5 wt% or more and 3 wt% or less. When the addition amount is within this range, the mechanical properties of the cured product can be sufficiently ensured even when the photosensitive resin composition is photocured in the atmosphere.

[Thermal polymerization initiator]
In the present invention, the curable resin composition may be a thermosetting resin composition, and the curable resin composition layer may be cured by heat. In this case, the curable resin composition preferably contains a thermal polymerization initiator.
As the thermal polymerization initiator, suitable compounds are all thermal polymerization initiators that can be used in radical polymerization reactions and ring-opening polymerization reactions. Examples of thermal polymerization initiators used in radical polymerization reactions include organic peroxides, inorganic peroxides, organic silicon peroxides, hydroperoxides, azo compounds, thiol compounds, phenol resins, amino resins, halogen compounds, aldehyde compounds Etc. Moreover, as a thermal polymerization initiator used for the ring-opening polymerization reaction, it is preferable to select a latent thermal polymerization initiator in which a thermal polymerization initiator is put in a microcapsule.
The thermal polymerization initiator is preferably in a liquid state at 20 ° C. from the viewpoint of easy mixing with the resin (b) or the organic compound (c).

  The content of the thermal polymerization initiator is preferably 0.1 wt% or more and 10 wt% or less, more preferably 0.5 wt% or more and 5 wt% or less, still more preferably 1 wt% with respect to the entire thermosetting resin composition. It is 5 wt% or less. If the content rate of a thermopolymerization initiator is the said range, a thermosetting resin composition can fully be hardened and it becomes possible to reduce the adhesiveness of the surface of a thermosetting material.

The selection of a suitable thermal polymerization initiator is particularly important in carrying out the method of the present invention. The thermal stability of the thermal polymerization initiator is usually determined by the 10 hour half-life temperature (10 h-t1 / 2), ie 50% of the initial amount of thermal polymerization initiator decomposes after 10 hours and is free radical. Is indicated by the temperature at which Further details on this are given in “Encyclopedia of Polymer Science and Engineering”, Vol. 11, page 1 onwards, John Wiley & Sons, New York, 1988.
The thermal polymerization initiator preferably has a 10 h-t1 / 2 of at least 60 ° C, more preferably at least 70 ° C. Especially preferably, it is 10 h-t1 / 2 of 80 to 150 degreeC.

  As the thermopolymerization initiator, an organic peroxide is particularly preferable from the viewpoint of thermosetting and compatibility with the thermosetting resin composition. Specific examples include peroxyesters such as t-butyl peroctanoate, t-amyl peroctanoate, t-butyl peroxyisobutyrate, t-butyl peroxymaleate, t-amyl perbenzoate, diperoxyphthal. Di-t-butyl acid, t-butyl perbenzoate, t-butyl peracetate and 2,5-di (benzoylperoxy) -2,5-dimethylhexane, certain diperoxyketals such as 1,1- Di (t-amylperoxy) cyclohexane, 1,1-di (t-butylperoxy) cyclohexane, 2,2-di (t-butylperoxy) butane and ethyl 3,3-di (t-butylperoxy) butyrate Some dialkyl peroxides, such as di-tert-butyl peroxide, tert-butyl cumyl peroxide, dicumyl peroxide Sid and 2,5-di (t-butylperoxy) -2,5-dimethylhexane, certain diacyl peroxides such as dibenzoyl peroxide and diacetyl peroxide, certain t-alkyl hydroperoxides such as t-butylhydro Peroxides, t-amyl hydroperoxide, pinane hydroperoxide and cumyl hydroperoxide.

[Fine particles]
In the present invention, one or more selected from inorganic fine particles, organic fine particles and organic-inorganic composite fine particles can be added to the curable resin composition. Improvement of mechanical properties of printing plate layer (printing plate layer) obtained by adding these fine particles, improvement of wettability of printing plate layer surface, adjustment of viscosity of curable resin composition, cured resin composition It is possible to adjust the viscoelastic properties of the resin. The material of the inorganic fine particles or organic fine particles is not particularly limited, and known materials can be used. Examples of the organic / inorganic composite fine particles include fine particles in which an organic layer or organic fine particles are formed on the surface of inorganic fine particles, or fine particles in which an inorganic layer or inorganic fine particles are formed on the surface of organic fine particles.

For the purpose of improving the mechanical properties of the printing original plate layer (printing plate layer), inorganic fine particles having high rigidity such as silicon nitride, boron nitride and silicon carbide, or organic fine particles such as polyimide can be used. Furthermore, for the purpose of improving the solvent resistance of the printing original plate layer (printing plate layer), inorganic fine particles and organic fine particles formed of a material having a good swelling property in the solvent to be used can be added.
In addition, for the purpose of forming a concave pattern on the surface of the cylindrical printing original plate by the laser engraving method, inorganic porous fine particles having excellent adsorption / removal characteristics for viscous liquid residues generated during laser engraving may be added. Although not particularly limited, for example, porous silica, mesoporous silica, silica-zirconia porous gel, porous alumina, porous glass and the like can be mentioned.

  In the present invention, the fine particles preferably have a number average particle diameter of 0.01 to 100 μm. When the fine particles having the number average particle size are used, there is no inconvenience such as increase in viscosity, entrainment of bubbles, and generation of a large amount of dust when mixing with the resin (b) and the organic compound (c). Unevenness does not occur on the surface of the cured photosensitive resin. A more preferable range of the average particle diameter is 0.1 to 20 μm, and a further preferable range is 1 to 10 μm. Here, the average particle size of the fine particles refers to a value measured using a laser scattering type particle size distribution measuring device.

The particle shape of the fine particles is not particularly limited, and spherical, flat, needle-like, amorphous, or particles having protrusions on the surface can be used. In particular, spherical particles are preferable from the viewpoint of wear resistance.
Further, the surface of the fine particles can be coated with a silane coupling agent, a titanium coupling agent, or other organic compound and subjected to a surface modification treatment to make the particles more hydrophilic or hydrophobic.
In the present invention, these fine particles can be selected from one type or two or more types.

The ratio of the resin (b), the organic compound (c), and the fine particles in the curable resin composition is usually 5 to 200 parts by weight of the organic compound (c) with respect to 100 parts by weight of the resin (b). Preferably, it is in the range of 20 to 100 parts by weight. Moreover, it is preferable that it is 1-100 weight part with respect to 100 weight part of resin (b), and it is more preferable that it is the range of 2-50 weight part. A more preferable range is 2 to 20 parts by weight.
In addition, a polymerization inhibitor, an ultraviolet absorber, a lubricant, a surfactant, a plasticizer, a fragrance and the like can be added to the photosensitive resin composition of the present invention according to the use and purpose.

When the ratio of the organic compound (c) is in the above range, it is easy to adjust the balance between the hardness and tensile strength / elongation of the sheet-like resin, and the shrinkage at the time of curing falls within a small range, thus ensuring the thickness accuracy. can do.
In addition, various additives such as a polymerization inhibitor, an ultraviolet absorber, a lubricant, a surfactant, a plasticizer, and a fragrance can be added to the resin composition for constituting the sheet-like resin depending on the purpose and purpose. .

[Method for producing printing original layer sheet]
In the present invention, an existing resin molding method can be used for molding the printing original layer sheet.
For example, a method of spraying using a spray, such as a casting method, a method of extruding a resin from a nozzle or a die with a machine such as a pump or an extruder, and adjusting the thickness with a blade, or adjusting the thickness by calendering with a roll It can be illustrated. In that case, it is also possible to perform the molding while heating the resin composition within a range that does not cause thermal decomposition. Moreover, you may perform a rolling process, a grinding process, etc. as needed.

[Cushion layer]
In the present invention, a cushion layer made of an elastomer can be formed below the printing original plate layer layer. The cushion layer is preferably an elastomer layer having a Shore A hardness of 10 to 70 degrees, or an ASKER-C hardness of 20 to 85 degrees as measured with an ASKER-C hardness meter. When the Shore A hardness is 10 degrees or more, or the ASKER-C hardness is 20 degrees or more, the print quality can be ensured because it is appropriately deformed. Moreover, if Shore A hardness is 70 degrees or less or ASKER-C hardness is 85 degrees or less, it can serve as a cushion layer. A more preferable range of Shore A hardness is 20 to 60 degrees, and an ASKER-C hardness is 45 to 75 degrees. The Shore A hardness and the ASKER-C hardness are preferably selected depending on the material used for the cushion layer. The difference between the two types of hardness stems from the difference in the shape of the pushers of the hardness meter used for measurement. When the cushion layer is composed of a uniform resin composition, it is preferable to use Shore A hardness, and it is composed of a resin composition having a non-uniform composition, such as a foaming base material such as foamed polyurethane and foamed polyethylene. In this case, it is preferable to use ASKER-C hardness. ASKER-C hardness is a measuring method based on JIS K7312 standard.

  Examples of the material for forming the cushion layer include materials having rubber elasticity such as thermoplastic elastomers, photocurable elastomers, and thermosetting elastomers. In particular, from the viewpoint of processability to a cylindrical printing original plate, it is convenient and preferable to use a liquid photosensitive resin composition material that is cured with light and becomes an elastomer after curing.

  The cushion layer preferably contains a cured photosensitive resin and contains bubbles or organic fine particles. The organic fine particles are preferably hollow microcapsules, and those having inorganic fine particles attached to the surface of the hollow microcapsules are preferably used. It is preferable that the average particle diameter of the organic fine particles is 1 μm or more and 500 μm or less. A more preferable range is 10 μm or more and 300 μm or less, and more preferably 80 μm or more and 200 μm or less.

The density of the cushion layer is preferably 0.1 g / cm ³ or more 0.9 g / cm ³ or less. More preferably, it is 0.3 g / cm ³ or more and 0.7 g / cm ³ or less, and further preferably 0.4 g / cm ³ or more and 0.6 g / cm ³ or less. If the density of the cushion layer is within this range, the impact applied to the laser engraving layer in the printing process can be sufficiently absorbed.

  Specific examples of the thermoplastic elastomer used for the cushion layer include SBS (polystyrene-polybutadiene-polystyrene), SIS (polystyrene-polyisoprene-polystyrene), SEBS (polystyrene-polyethylene / polybutylene-polystyrene), which are styrenic thermoplastic elastomers, and the like. Olefin-based thermoplastic elastomer, urethane-based thermoplastic elastomer, ester-based thermoplastic elastomer, amide-based thermoplastic elastomer, silicon-based thermoplastic elastomer, fluorine-based thermoplastic elastomer, and the like.

In addition, as the photocurable elastomer, a liquid photosensitive resin in which a photopolymerizable monomer, a plasticizer, a photopolymerization initiator, and the like are mixed with the thermoplastic elastomer, and a liquid resin is mixed with a photopolymerizable monomer, a photopolymerization initiator, and the like. For example, a functional resin composition. With respect to the cushion layer, it is not necessary to form a fine pattern using light, and it is sufficient if the necessary mechanical strength can be ensured by curing by full exposure. Therefore, the degree of freedom in selecting a material is extremely high.
In addition, as a material for forming the cushion layer, sulfur-crosslinked rubber, organic peroxide, phenol resin initial condensate, quinone dioxime, metal oxide, thiourea, etc. are used as a crosslinking agent. Mold rubber may be used. Furthermore, it is also possible to use a three-dimensionally crosslinked elastomer obtained by using a curing agent that reacts with a telechelic liquid rubber.

  The cushion layer may be made of a material such as polyurethane foam or polyethylene foam, and may have independent or open cells in the layer. Commercially available cushion materials and cushion tapes can also be used. An adhesive or a pressure-sensitive adhesive may be applied to one side or both sides of the cushion layer.

[Laser engraving]
When forming a pattern on a cylindrical printing original plate produced by the production method of the present invention using a laser engraving method, a laser engraving machine is operated using a computer as an image to be formed as digital data, and the printing original plate Create a relief image on the layer. Any laser may be used for the laser engraving as long as the original plate includes a wavelength having absorption. However, in order to perform engraving at a high speed, a laser with a high output is desirable. Infrared or infrared emitting solid lasers such as YAG lasers and semiconductor lasers are preferred. In addition, the second harmonic of a YAG laser having an oscillation wavelength in the visible light region, a copper vapor laser, an ultraviolet laser having an oscillation wavelength in the ultraviolet region, such as an excimer laser, and a YAG laser wavelength-converted to the third or fourth harmonic are It can be ablated by cutting the bonds of organic molecules and is suitable for fine processing. The laser may be continuous irradiation or pulse irradiation.

Engraving with a laser (β) is performed in an oxygen-containing gas, generally in the presence of air or an air stream, but can also be performed in a carbon dioxide gas or a nitrogen gas. After engraving is finished, the powdery or liquid substance slightly generated on the relief printing plate surface is washed with an appropriate method such as water containing a solvent or a surfactant, or a water-based cleaning agent is irradiated by a high-pressure spray or the like. Alternatively, it may be removed using a method of irradiating high-pressure steam.
In the present invention, after engraving to irradiate a laser beam (β) to form a concave pattern, following the step of removing powdery or viscous liquid residue remaining on the plate surface, the surface of the printing plate on which the pattern is formed has a wavelength of 200 nm. Post-exposure by irradiating light of ˜450 nm can also be performed. This is an effective method for removing tack on the surface. The post-exposure may be performed in any environment such as air, inert gas atmosphere, and water. This is particularly effective when the photosensitive resin composition used contains a hydrogen abstraction type photopolymerization initiator. Furthermore, before the post-exposure step, the printing plate surface may be exposed to a treatment liquid containing a hydrogen abstraction type photopolymerization initiator. Moreover, you may expose in the state which immersed the printing plate in the process liquid containing a hydrogen abstraction type photoinitiator.

In order to describe the present embodiment in more detail, examples and comparative examples are shown below, but these examples specifically illustrate the description of the present embodiment and the effects obtained thereby. Thus, the present embodiment is not limited at all. Various characteristics in the following examples and comparative examples were measured according to the following methods.
[Measuring method]
(1) Laser engraving Laser engraving is a carbon dioxide laser engraving machine (trademark: ZED-mini-1000, UK, manufactured by ZED, USA, coherent, output 250W carbon dioxide laser, laser oscillation wavelength is 10.6 μm ). Engraving was performed by creating a dot pattern (120 lines / inch, area ratio 10%). The engraving depth was 0.55 mm.
(2) Viscosity The viscosity of the fat composition or the organic compound (c) was measured at 20 ° C. using a B-type viscometer (trademark, B8H type; manufactured by Tokyo Keiki Co., Ltd., Japan).
(3) Measurement of number average molecular weight The number average molecular weights of the resin (b) and the organic compound (c) were determined by conversion with polystyrene having a known molecular weight using a gel permeation chromatography method (GPC method). Using a high-speed GPC device (trade name, HLC-8020, manufactured by Tosoh Corporation, Japan) and a polystyrene packed column (trademark: TSKgel GMHXL; manufactured by Tosoh Corporation, Japan), the measurement was performed with tetrahydrofuran (THF). The column temperature was set to 40 ° C. As a sample to be injected into the GPC apparatus, a THF solution having a resin concentration of 1 wt% was prepared, and the injection amount was 10 μl. A differential refractometer was used as the detector.

Example 1
1. Process (1)
As resin (b), 70 parts by mass of polycarbonate polyurethane having a number average molecular weight of approximately 100,000 (trade name “Rezamin P890”, manufactured by Dainichi Seika Co., Ltd.), and as organic compound (c), 30 parts by mass of phenoxyethyl methacrylate (molecular weight 190). And 1 part by mass of trimethylolpropane triacrylate (molecular weight 338), 5 parts by mass of porous fine-powdered silica (trade name “Cyrossphere C-1504” manufactured by Fuji Silysia Chemical Ltd.), 0.5 wt. Of benzophenone as a photopolymerization initiator Part and 2,2-dimethoxy-2-phenylacetophenone 0.6 parts by mass, 2,6-di-t-butylacetophenone 0.5 part by mass as a stabilizer, a small-capacity pressure type kneader (manufactured by Moriyama, "D1 -5 ") and mixing at a temperature of 130 ° C to prepare a curable fat composition. The obtained curable photosensitive resin composition was extruded at a thickness of 1 mm onto a 50 μm-thick PET base film on which the adhesive was thinly applied on the surface by using a biaxial extrusion device. A layer was formed, and a 50 μm-thick cover film that had been subjected to silicone release treatment was laminated thereon to form a laminated sheet. This curable resin composition was solid at 20 ° C.
The obtained laminated sheet was cut into a width of 180 mm and a length of 710 mm to obtain a printing original layer sheet.

2. Process (2)
From both ends parallel to the short side direction of the printing original plate layer sheet, each part of the surface of the curable resin composition layer in the overlapping margin portion 5 mm inside was removed as follows. An aluminum foil tape was pasted on top to make a light shielding mask. Next, the printing original layer sheet is placed on a metal stage with the surface on which the light shielding mask is formed facing upward, and light from a parallel light exposure machine using an ultrahigh pressure mercury lamp as a light source is applied to the entire surface of the sheet from the light shielding mask side. It was irradiated with 4000 mJ / cm ² (accumulated light amount at a wavelength of 350 nm), and only the overlapping portion at both ends was an uncured cured product.
Place the PET base film of the printing original layer sheet on the porous metal stage that is electronically cooled to -30 ° C using a Peltier element, and vacuum the PET base film side at the end of the winding start side. In a state where it is fixed so that it does not move by adsorption, the end cover film is cut into a 5 mm wide band with a cutter, and the uncured curable resin composition layer of the overlapping margin portion on the winding start end side, From a top surface to a depth of 0.6 mm, a 5 mm strip was cut using a milling tool (step (2-a)).
Next, the printing original plate layer sheet, this time, with the surface on which the PET base film is laminated facing up, the end portion on the trailing end side is fixed to the adsorption stage, and the PET base film at the end portion is 5 mm wide with a cutter. Then, the curable resin composition layer in an uncured state was cut into a strip having a width of 5 mm using a slicing tool from the surface to a depth of 0.41 mm (step (2-b)). ).

70 parts by mass of polycarbonate polyurethane having a number average molecular weight of approximately 100,000 (trade name “Rezamin P890” manufactured by Dainichi Seika Co., Ltd.), 30 parts by mass of phenoxyethyl methacrylate (molecular weight 190) and 1 part by mass of trimethylolpropane triacrylate (molecular weight 338) , 5 parts by mass of carbon black and 0.5 parts by mass of 2,6-di-t-butylacetophenone as a stabilizer were mixed at a temperature of 130 ° C. using a kneader, then cooled to 70 ° C., and a thermal polymerization initiator 1 part by mass of t-butylperoxy-2-ethylhexyl carbonate (trade name “Perbutyl E” manufactured by NOF Corporation) was added to prepare a thermosetting resin composition. The obtained thermosetting resin composition was dissolved in toluene, applied onto a release-treated PET film, and the toluene was removed by drying to obtain a sheet for forming a laser absorption layer having a thickness of 100 μm.
The light absorbing layer forming sheet produced as described above is laminated on the upper surface of the curable resin composition layer of the overlapping margin portion on the winding start end side, part of which has been removed, with the PET base film facing up, This laminate was sandwiched between glass plates (step (2-c)).
Subsequently, the laser beam of the wavelength which a light absorption layer absorbs was irradiated from the PET base film side of the printing original plate layer sheet, and the laser absorption layer was welded to the printing original plate layer sheet (process (2-d)). The laser used here was a semiconductor laser having a wavelength of 940 nm, the average output was 30 W, and the laser beam diameter was 2 mm. A cross-sectional view of this printing original plate layer sheet is shown in FIG.
Further, the uncured resin below the light absorption layer was photocured.
Finally, the cover film was peeled off.

3. Step (3)
A glass fiber reinforced plastic (epoxy resin) having a thickness of 0.45 mm is attached to a metal air cylinder, and an anaerobic adhesive (trade name “TB-1530”, manufactured by ThreeBond Co., Ltd.) is applied to the surface with a thickness of 0.1 mm. A cylindrical support was prepared by leaving it in an environment of 60% humidity for 10 minutes. On top of that, the printing original plate layer sheet treated at both ends is wound so that air bubbles do not enter the PET base film, and then the light absorption layer of the overlapping margin portion on the winding start end side is formed. The surface and the lower surface of the overlap margin portion on the winding end side were overlapped.
4). Step (4)
Further, a glass plate is laminated on the overlapped portion, and the laser beam having the wavelength absorbed by the light absorption layer is irradiated through the glass plate while being moved, and the entire surface of the light absorption layer is wound and the overlap margin portion on the terminal end side is wound. Welded to.

5). Step (5)
Finally, the uncured portion was irradiated with 4000 mJ / cm ² of light from a metal halide lamp (manufactured by Fusion, USA) and photocured to prepare a cylindrical printing original plate. A cross-sectional view of the joint portion of this cylindrical printing original plate is shown in FIG.
The thickness of the overlap margin portion was 0.02 mm thinner than the average value of the other 10 portions. The accuracy of the outer diameter of the cylindrical printing original plate excluding the overlap margin portion (joint portion) was ± 15 μm.

A concave pattern was formed on the surface of the produced cylindrical printing original plate using a carbon dioxide laser engraving machine. In the overlapping portion, the engraving depth was 0.4 mm at the deepest portion. At the time of laser engraving, the air cylinder was rotated at a linear velocity of 10 m / sec, but the printing original layer sheet was not peeled off from the cylindrical support.
The obtained cylindrical printing plate was attached to an air cylinder of a dry offset can printing machine (manufactured by Stoma Machinery Inc., USA), and printing was performed on the surface of the aluminum can. Although printing was performed at a speed of 20 lines / second, the printing plate layer (printing original layer sheet) was not peeled off from the cylindrical support (glass fiber reinforced plastic sleeve).

(Example 2)
1. Process (1)
The same printing original plate layer sheet prepared in Example 1 was prepared.
2. Process (2)
Place the PET base film of the printing original layer sheet on the porous metal stage that is electronically cooled to -30 ° C using a Peltier element, and vacuum-adsorb the PET base film side at the winding end side. In a state where it is fixed so that it does not move, the cover film at the end thereof is cut into a strip having a width of 5 mm, and the curable resin composition layer of the overlapping margin portion on the winding start end side is brought to a depth of 0.6 mm from the surface. Then, it was cut into a 5 mm strip using a milling tool (step (2-a)).
Next, the printing original plate layer sheet is fixed to the suction stage with the end where the PET base film is laminated facing up, and the end of the winding end side is fixed to the adsorption stage, and the PET base film at the end is 5 mm wide with a cutter. It peeled after cut | disconnecting in strip | belt shape, and then cut the uncured curable resin composition layer into strip | belt shape of a width of 5 mm using the slice tool to the depth of 0.41 mm (process (2-b)).
In the same manner as in Example 1, a light absorption layer was formed at the stacking margin and fused (step (2-c), step (2-d)).
Next, the PET base film is irradiated with 50 mJ / cm ² (integrated light quantity at a wavelength of 350 nm) of a chemical lamp (“10R”, Lankoku, Philips) from the PET base film side of the printing original layer sheet. The side curable resin composition was partially cured.
Finally, the cover film was peeled off.

3. Step (3)
A glass fiber reinforced plastic (epoxy resin) having a thickness of 0.45 mm is attached to a metal air cylinder, and an anaerobic adhesive (trade name “TB-1530”, manufactured by ThreeBond Co., Ltd.) is applied to the surface with a thickness of 0.1 mm. It was left for 10 minutes in an environment of 60% humidity. On top of that, the printing original plate layer sheet treated with the edge was wound so that the PET base film was inside so that bubbles would not enter, and both ends were overlapped.

4). Step (4)
Thereafter, a glass plate was placed on the overlapped portion, and the aforementioned semiconductor laser light was irradiated through the glass plate, and the laser light was moved to adhere the entire surface of the light absorption layer. Calendering was performed with a metal roll heated to 130 ° C. to adjust the surface.

5). Step (5)
Furthermore, while rotating the air cylinder, the curable resin composition layer of the printing original plate layer sheet was irradiated with light of a metal halide lamp (manufactured by US Fusion) at 4000 mJ / cm ² and photocured to prepare a cylindrical printing original plate. .
The thickness of the overlap margin portion was 0.5 mm thinner than the average value of the other 10 portions. The accuracy of the outer diameter of the cylindrical printing original plate excluding the overlap margin was within ± 15 μm.
After laser engraving in the same manner as in Example 1, it was used for dry offset printing. At the time of laser engraving, the sheet-shaped resin was not peeled off from the support during printing.

(Example 3)
1. Process (1)
As resin (b), 70 parts by mass of a styrene-butadiene-styrene block copolymer having a number average molecular weight of about 100,000, as an organic compound (c), 10 parts by mass of hexamethylene diacrylate (molecular weight 254), and number average molecular weight 2000 15 parts by mass of liquid polybutadiene, 10 parts by mass of alicyclic hydrocarbon plasticizer, 5 parts by mass of porous fine-powdered silica (trade name “Cyrossphere C-1504” manufactured by Fuji Silysia Chemical Ltd.), benzophenone as a photopolymerization initiator 0.5 parts by mass and 0.6 parts by mass of 2,2-dimethoxy-2-phenylacetophenone, 0.5 parts by mass of 2,6-di-t-butylacetophenone as a stabilizer using a small-capacity pressure type kneader The mixture was mixed at a temperature of 130 ° C. to prepare a curable resin composition (photosensitive resin composition). Thickness of the obtained curable resin composition on a PET base film having a thickness of 100 μm, on which the adhesive is thinly applied on the surface, using a biaxial extruder (“KZW-TW” manufactured by Technobel) Extrusion was performed at 1.7 mm to form a curable resin composition layer, and a 50 μm-thick cover sheet subjected to silicone release treatment was laminated thereon to form a laminated sheet. This curable resin composition was solid at 20 ° C.
The obtained laminated sheet was cut into a width of 500 mm and a length of 710 mm to obtain a printing original layer sheet.

2. Process (2)
From both ends parallel to the short side direction of the printing original plate layer sheet, a part of the surface of the curable resin composition layer at the overlapping margin portion 5 mm inside was removed as follows.
First, an aluminum foil tape was pasted on a cover film having a width of 5 mm at both ends to form a light shielding mask. Next, the printing original layer sheet is wound on a metal cylinder with the light shielding mask side up, and light from a parallel light exposure machine using an ultrahigh pressure mercury lamp as a light source is applied to the entire surface of the sheet from the light shielding mask side to 4000 mJ / cm ^2. Irradiation (integrated light quantity at a wavelength of 350 nm) was performed, and only the overlapping portion at both ends was an uncured cured product.
Place the PET base film of the printing original layer sheet on the porous metal stage that is electronically cooled to -30 ° C using a Peltier element, and vacuum-adsorb the PET film side at the end of the winding start side. With the cover film fixed so that it does not move, the cover film at the end is removed with a cutter into a band with a width of 5 mm, and the uncured curable resin composition layer of the overlap margin portion on the winding start end side is To 1 mm in depth using a milling tool (step (2-a)).
Next, the printing original plate layer sheet, this time, with the surface on which the PET base film is laminated facing up, the end on the winding end side is fixed to the adsorption stage, and the PET base film at the end is 5 mm wide with a cutter. It peeled after cut | disconnecting in strip | belt shape, and then cut the uncured curable resin composition layer into strip | belt shape of width of 5 mm using the slice tool from the surface to the depth of 0.71 mm (process (2-b)). .
In the same manner as in Example 1, a light absorption layer is formed and welded on the overlapping portion (steps (2-c) and (2-d)), and an uncured curable resin composition below the light absorption layer. The film was irradiated with light from an ultrahigh pressure mercury lamp and photocured.
Finally, the cover film was peeled off.

3. Process (3)-(5)
In the same manner as in Example 1, a cylindrical printing original plate was produced.
The thickness of the overlap margin portion was 0.1 mm thinner than the average value of the other 10 portions. The accuracy of the outer diameter of the cylindrical printing original plate excluding the overlapping portion was ± 20 μm.

A concave pattern was formed on the surface of the produced cylindrical printing original plate using a carbon dioxide laser engraving machine. The welded end was 0.4 mm at the deepest part of the engraving depth. At the time of laser engraving, the air cylinder was rotated at a linear velocity of 10 m / sec, but the printing original layer sheet was not peeled off from the cylindrical support.
The obtained cylindrical printing plate was attached to an air cylinder of a flexographic printing machine (manufactured by Iyo Machinery Co., Ltd.), and printing was performed on the surface of the polyethylene film. Although printing was performed at a speed of 300 m / min, the printing plate layer was not peeled off from the cylindrical support (glass fiber reinforced plastic sleeve).

Example 4
1. Process (1)
The same printing original plate layer sheet prepared in Example 3 was prepared.
2. Process (2)
Place the surface of the printing original plate layer sheet on which the PET base film is laminated and place it on a porous metal stage that has been electronically cooled to −30 ° C. using a Peltier device, and place the end of the winding start side on the PET base film side. The cover film at the end is removed with a cutter into a strip with a width of 5 mm, and the curable resin composition layer at the overlap margin portion on the winding start end side is removed from the surface. It was cut into a strip shape using a cutter to a depth of 6 mm (step (2-a)).
Next, the printing original plate layer sheet is turned upside down on the surface on which the PET base film is laminated, and the end portion on the winding end side is fixed to the adsorption stage, and the PET base film at the end portion is 5 mm wide with a cutter. It peeled after cut | disconnecting in strip | belt shape, and then cut the curable resin composition layer with the cutter to the depth of 0.41 mm from the surface (process (2-b)).

The light-absorbing layer forming sheet used in Example 1 was laminated on the upper surface of the curable resin composition layer in the overlapping margin portion on the winding start end side from which a part was removed, and this lamination was performed. The body was sandwiched between glass plates (step (2-c)).
Next, laser light having a wavelength absorbed by the light absorption layer was irradiated from the PET base film side of the printing original layer sheet, and the light absorption layer was welded to the printing original layer sheet (step (2-d)). The laser used here was a semiconductor laser having a wavelength of 940 nm, the average output was 30 W, and the laser beam diameter was 2 mm.
Furthermore, 50 mJ / cm ^{2 of} chemical lamp light was irradiated from the PET base film side to partially cure the portion of the curable resin composition in contact with the PET base film.
Finally, the cover film was peeled off.

3. Step (3)
A glass fiber reinforced plastic (epoxy resin) having a thickness of 0.45 mm is attached to a metal air cylinder, and an anaerobic adhesive (trade name “TB-1530”, manufactured by ThreeBond Co., Ltd.) is applied to the surface with a thickness of 0.1 mm. A cylindrical support was prepared by leaving it in an environment of 60% humidity for 10 minutes. On top of that, the printing original plate layer sheet treated at both ends is wound so that air bubbles do not enter, and then the PET film is placed inside, and then the upper surface on which the light absorption layer of the overlapping margin portion on the winding start end side is formed Then, the lower surface of the overlap margin portion on the winding end side was overlapped.
4). Step (4)
Furthermore, a glass plate is installed on the overlapped portion, and the laser beam having the wavelength absorbed by the light absorption layer is irradiated through the glass plate while moving, and the entire surface of the light absorption layer is wound and welded to the overlap portion on the end side. I let you.

5). Step (5)
An exposure mask made of PET was wrapped around the surface of the obtained cylindrical printing original plate, and exposed to light from a chemical lamp through the exposure mask to cure the curable resin composition into a pattern. After removing the exposure mask, the surface of the cylindrical printing original plate was irradiated with infrared rays to melt the uncured portion, and the molten resin was absorbed and removed with a nonwoven fabric. A cylindrical printing plate having a pattern on the surface was obtained by repeatedly performing absorption removal with a nonwoven fabric about 10 times. Furthermore, the entire surface of the cylindrical printing plate was irradiated with chemical lamp light to be completely cured.

  The obtained cylindrical printing plate was attached to an air cylinder of a flexographic printing machine (manufactured by Iyo Machinery Co., Ltd.), and printing was performed on the surface of the polyethylene film. Although printing was performed at a speed of 300 m / min, the printing plate layer was not peeled off from the cylindrical support.

(Example 5)
70 parts by mass of polycarbonate polyurethane having a number average molecular weight of about 100,000 (trade name “Rezamin P890”, manufactured by Dainichi Seika Co., Ltd.), 30 parts by mass of phenoxyethyl methacrylate (molecular weight 190) and 1 part by mass of trimethylolpropane triacrylate (molecular weight 338) , 3 parts by weight of near-infrared absorbing phthalocyanine (manufactured by Nippon Shokubai Co., Ltd., trade name “EEX Color IR-906”), 0.5 parts by weight of 2,6-di-t-butylacetophenone as a stabilizer, and temperature using a kneader Mix at 130 ° C., then cool to 70 ° C., add 1 part by mass of t-butyl peroxy-2-ethylhexyl carbonate (trade name “Perbutyl E” manufactured by NOF Corporation) as a thermal polymerization initiator, A curable resin composition was prepared. The obtained thermosetting resin composition was dissolved in toluene, applied onto a release-treated PET film, and toluene was removed by drying to obtain a light absorption layer having a thickness of 100 μm.
A cylindrical printing original plate was produced in the same manner as in Example 1 except that the light absorbing layer forming sheet thus prepared was used.

In the same manner as in Example 1, a concave pattern was formed on the surface of the cylindrical printing original plate. At the time of laser engraving, the air cylinder was rotated at a linear velocity of 10 m / sec, but the printing original layer sheet was not peeled off from the cylindrical support.
The obtained cylindrical printing plate was attached to an air cylinder of a flexographic printing machine (manufactured by Iyo Machinery Co., Ltd.), and printing was performed on the surface of the polyethylene film. Although printing was performed at a speed of 300 m / min, the printing plate layer was not peeled off from the cylindrical support (glass fiber reinforced plastic sleeve).

(Comparative Example 1)
The printing original plate layer sheet produced in Example 1 was wound around the hollow cylindrical support used in Example 1, and tapes were attached and fixed to both ends of the printing original plate layer sheet. On the surface of the uncured resin composition layer, irregularities such as traces of hand contact were visually observed. Thereafter, light from a metal halide lamp (trade name “F450V type UV lamp” manufactured by Fusion Co., Ltd.) was exposed at 350 nm under the condition of 8000 mJ / cm ² to obtain a cylindrical printing original plate.
Voids were observed in some places between the hollow cylindrical support of the obtained cylindrical printing original plate and the sheet-like photosensitive resin cured product. The outer diameter accuracy of the cylindrical printing original plate was ± 80 μm.
After laser engraving on the obtained cylindrical printing original plate and forming an image pattern on the surface, dry offset printing was performed in the same manner as in Example 1. However, due to the unevenness of the surface, printing defects corresponding to the unevenness occurred.

  The printing original plate produced by the production method of the present invention can be formed into various printing plates such as flexographic printing, dry offset printing, and gravure printing by forming a pattern on the surface by a laser engraving method.

The printing original plate layer sheet which formed the light absorption layer produced in Example 1 Sectional drawing of the joint part of the cylindrical printing original plate produced in Example 1

Explanation of symbols

10: Support for printing original layer sheet 11: Curable resin composition layer 12: Light absorption layer 13: Cylindrical support 14: Adhesive layer

Claims (21)

A method for producing a cylindrical printing original plate by winding a printing original layer sheet around a cylindrical support, comprising the following steps (1) to (5);
(1) preparing a printing original plate layer sheet having an uncured curable resin composition layer;
(2) Process of processing both ends of the printing original plate layer sheet including the following steps (2-a) to (2-d):
(2-a) a step of partially removing the upper surface of the curable resin composition layer of the overlapping margin portion on the side to be a winding start end when the printing original plate layer sheet is wound around the cylindrical support;
(2-b) a step of partially removing the lower surface of the curable resin composition layer of the overlap margin portion on the side to be the winding end when the printing original plate layer sheet is wound around the cylindrical support;
(2-c) The light absorption which absorbs the light of a specific wavelength on the upper surface of the curable resin composition layer of the overlap margin part by the side made into the winding start end which removed the upper surface partially in the process (2-a) Forming a layer;
(2-d) a step of irradiating the light absorption layer formed in step (2-c) with laser light having a wavelength that is absorbed by the light absorption layer;
(3) A step of winding the printing original layer sheet around a cylindrical support and superimposing the overlapping margin on the winding start end side and the overlapping margin on the winding end side;
(4) A step of irradiating a portion of the light absorption layer superposed in step (3) with laser light having a wavelength that is absorbed by the light absorption layer;
(5) A step of curing the uncured curable resin composition.   2. The laser engraving according to claim 1, wherein in the step (2-a) and / or (2-b), partial removal of the surface of the cured resin composition layer is performed by fixing an end portion of the printing original plate layer sheet. Of manufacturing a cylindrical printing original plate.   The method for producing a cylindrical printing original plate for laser engraving according to claim 2, wherein the method of fixing the end portion of the printing original layer sheet is a method of adsorbing in a reduced pressure state.   The method of adsorbing in the reduced pressure state is a method in which an end portion of the printing original plate layer sheet is brought into contact with an adsorption jig having a porous body on the surface and sucked to the reduced pressure through the porous body. A method for producing a cylindrical printing original plate.   In the step (2-a) and / or (2-b), whether or not the surface of the curable resin composition layer is partially removed by cutting the cured resin composition layer with a blade in a direction parallel to and perpendicular to the sheet. The method for producing a cylindrical printing original plate for laser engraving according to claim 1, wherein the method is performed by cutting or grinding.   In the step (2-a) and / or (2-b), the surface of the curable resin composition layer is partially removed while the curable resin composition layer is cooled to -50 ° C or higher and 10 ° C or lower. A method for producing a cylindrical printing original plate for laser engraving according to any one of claims 1 to 5.   The composition constituting the curable resin composition layer includes at least one resin selected from polyamide, polyester, polyurethane, styrene-butadiene copolymer, and styrene-isoprene copolymer. The manufacturing method of the cylindrical printing original plate in any one.   The manufacturing method of the cylindrical printing original plate in any one of Claim 1 to 6 whose composition which comprises the said curable resin composition layer is a photosensitive resin composition.   The manufacturing method of the cylindrical printing original plate in any one of Claim 1 to 8 whose Shore D hardness of the printing original printing layer of the cylindrical printing original plate manufactured is 10 to 100 degree | times.   The manufacturing method of the cylindrical printing original plate in any one of Claim 1 to 9 in which the said cylindrical support body has an adhesive bond layer or an adhesive layer on the surface.   The method for producing a cylindrical printing original plate according to claim 10, wherein the adhesive layer or the pressure-sensitive adhesive layer contains a photosensitive resin composition.   The manufacturing method of the cylindrical printing original plate of Claim 10 in which the said adhesive bond layer contains a pressure sensitive adhesive.   The manufacturing method of the cylindrical printing original plate of Claim 1 in which the said light absorption layer contains the dye or pigment which absorbs near infrared rays.   The method for producing a cylindrical printing original plate according to claim 1, wherein the light absorption layer contains at least one kind of thermoplastic resin.   The method for producing a cylindrical printing original plate according to claim 1, wherein the light absorption layer absorbs light having a wavelength in a range of 700 nm to 3 μm.   The laser light applied to the light absorption layer in the step (2-d) and / or the step (4) is light from a pulsed laser, and the pulse time half width is 10 femtoseconds or more and 50 microseconds. The method for producing a cylindrical printing original plate according to claim 1, wherein the oscillation frequency is 1 kHz to 500 MHz.   A method for producing a laser-engraved cylindrical printing plate, wherein a concave portion is formed by irradiating the surface of a cylindrical printing original plate produced by any one of claims 1 to 16 with laser light.   The method for producing a laser-engraved cylindrical printing plate according to claim 17, wherein the depth of the concave portion is thinner than the thickness of the printing plate layer at the joint portion of the cylindrical printing plate.   The method for producing a laser-engraved cylindrical printing plate according to claim 17 or 18, which is used for an application selected from the group consisting of flexographic printing, dry offset printing and gravure printing.   The method for producing a laser-engraved cylindrical printing plate according to claim 19, wherein the use is dry offset printing for printing on a curved surface.   The method for producing a laser-engraved cylindrical printing plate according to claim 19 or 20, wherein the dry offset printing is printing using an ink containing an aliphatic hydrocarbon and / or an aromatic hydrocarbon.

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