JPH0834159A - Production of aqueous ink recording sheet - Google Patents

Abstract

PURPOSE:To improve ink receptivity and to keep high gloss and excellent mapping proterties by forming the recording layer integrated with inner and outer coating layers to cure the same by the irradiation with electron beam and peeling the cured recording layer from a highly smooth molded surface. CONSTITUTION:A coating soln. containing an unsaturated org. compd. cured by the irradiation with electron beam as a main component is applied to one surface of a sheet like base material 11 composed of fine paper, coated paper or synthetic paper by a first coating device 10 to form an inside coating layer 12. A coating soln. containing a water-soluble or water-dispersible resin as a main component is applied to a highly smooth molded surface (metal cylindrical rotary body 5) by a second coating device 4 to be dried and irradiated if necessary with electron beam to form an outside coating layer. The inside coating layer on the base material 11 is superposed on the outside coating layer on the molded surface to be bonded to thereto under pressure to form a recording layer 16 wherein the outside and inside coating layers are integrated. The recording layer 16 is cured by the irradiation with electron beam 14 to be peeled from the highly smooth molded surface 5 by a peeling roll 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet using a water-based ink. More specifically, the present invention is a water-based ink recording sheet capable of obtaining a recorded image having high gloss and excellent image clarity by an ink jet recording system. It is about.

[0002]

2. Description of the Related Art An ink jet recording system, unlike a thermal transfer system, does not require an ink sheet, is easy to maintain, and does not require a developing and fixing process as in an electrophotographic system, so that the apparatus can be made compact. In addition, since high-speed, high-resolution color recording is possible, it has rapidly spread in recent years as a facsimile, a terminal printer, and a copying machine. A plain paper type is currently used as the inkjet recording sheet, but in the case of color recording, it is coated from the viewpoint of ink acceptability such as dot shape, dot sharpness, ink absorption, fixing speed, and ink absorption capacity. The engineering paper type is used.

Under such circumstances, high gloss even after receiving ink,
Although there is an increasing need for a photographic water-based ink recording sheet capable of obtaining a recorded image with excellent image clarity, a normal coated paper type water-based ink recording sheet is used in the drying process after coating the recording layer. In addition to the appearance of shrinkage unevenness on the surface, if a pigment is added to the recording layer in addition to the water-soluble or water-dispersible resin in order to satisfy the desired ink acceptability, the smoothness of the surface is further lowered and the gloss is reduced. Not.
In addition, a method of providing an ink recording layer on a highly smooth sheet-shaped substrate such as a plastic film or laminated paper to make it into a photograph has been attempted, but a pigment is blended in addition to a water-soluble or water-dispersible resin. Then, a product having high gloss and excellent image clarity cannot be obtained. When the water-soluble or water-dispersible resin alone is used, it has high gloss and excellent image clarity before receiving ink, but absorption of ink into the recording layer due to capillary phenomenon cannot be expected, and a sufficiently formed recording layer When the ink rapidly absorbs the ink, the recording layer swells and the surface is deformed due to cracks or wrinkles. In other words, if the ink acceptability is increased, the gloss and image clarity after ink reception are lowered, and if the gloss and image clarity after ink reception are attempted to be maintained, the ink acceptability becomes poor, and good ink acceptability and ink acceptance High gloss,
Nothing satisfying both excellent image clarity has been obtained.

On the other hand, a proposal has been made to prepare an aqueous ink recording sheet having ink receptivity by using an unsaturated organic compound which can be cured by an electron beam or an ultraviolet ray. For example, JP-A-60-143991 discloses the method. The method is
A high molecular weight unsaturated organic compound that is curable by electron beam or ultraviolet light dispersed in a mixed solvent of water and solvent is used.In this method, similar to the method using water-soluble or water-dispersible resin, plain paper or coating is used. In the case of a paper type base material, the surface smoothness is low and the surface is not glossy due to the texture. An unsaturated organic compound that can be cured by electron beams or ultraviolet rays is used.However, since it is a high molecular compound, the mobility of the crosslinking component in the dried coating film is low, its contribution to the crosslinking structure is small, and it is water-soluble. If the ink receptivity is increased as in the method using a water-soluble or water-dispersible resin, the gloss and image clarity after ink reception are lowered, and the ink receptivity becomes poor when the gloss and image clarity after ink reception are maintained. No one has been obtained that satisfies both ink acceptability, high gloss after ink acceptance, and excellent image clarity.

It is also possible to prepare an aqueous ink recording sheet by using an unsaturated organic compound having a solid content of 100% and curable by an electron beam or an ultraviolet ray.
No. 7, Japanese Patent Application Laid-Open No. 4-69277, and the like, this method provides a desired high gloss after receiving ink.
Although excellent image clarity is obtained, a versatile aqueous ink recording sheet cannot be obtained because of poor ink acceptability, particularly ink absorption speed and ink fixability. That is, no matter which base material is used, good ink acceptability and high gloss after ink reception,
A photographic water-based ink recording sheet satisfying both excellent image clarity has not been obtained.

[0006]

The present invention solves the above problems of the conventional water-based ink recording sheet, and even when plain paper, coated paper or the like is used as the sheet-shaped substrate,
It is an object of the present invention to provide a method for producing a water-based ink recording sheet that can obtain a recorded image having good image quality, high gloss, and excellent image clarity.

[0007]

The present inventors have found that even when a paper base material, such as plain paper or coated paper, which is significantly inferior in texture to a plastic film, is used as the sheet-like base material, the ink receiving In order to obtain a photographic water-based ink recording sheet having good properties, high gloss in addition to high image quality, and excellent image clarity, as a result of diligent studies, it was found that a main component is a water-soluble or water-dispersible resin having good ink acceptability. By applying the coating material on a molding surface with a highly smooth surface and drying it, the surface deterioration and the influence of texture that occur with the contraction of the base material are removed, and a high gloss even after receiving the ink on the base material. , Which can enhance the cross-linking structure of the coating so as to maintain excellent image clarity After applying a coating liquid containing an unsaturated organic compound as a main component that can be cured by electron beam irradiation, coating on the molding surface One layer by crimping with layers And, by then curing subjected to electron beam irradiation is peeled from the molding surface to form an ink recording layer,
The ink receptivity is better as it is closer to the surface layer, while the cross-linking structure that can maintain high gloss and excellent image clarity after ink reception is better as it is closer to the substrate and the physical properties of both can be changed continuously. It turned out to be necessary.

In other words, the dot shape, the sharpness of the dots, the ink absorption, the fixing speed, the ink acceptability such as the ink absorption capacity, the releasability that enables good transfer from the molding surface are satisfied, and the cross-linking structure is also to some extent. Ink receptivity within the range that does not impair the ink receptivity of the outer coating layer by coating the coating surface containing the resulting water-soluble or water-dispersible resin as the main component and drying it to form the outer coating layer. Has a cross-linking structure capable of maintaining high gloss and high image clarity even after receiving ink, and has adhesiveness with a substrate necessary for peeling from the molding surface. A coating containing a saturated organic compound as a main component is applied on a substrate to form an inner coating layer, and the inner coating layer and the outer coating layer are pressure-bonded to each other to coat the inner coating layer with the outer coating. It also penetrates into the layer paint, from the surface to the substrate. After forming a recording layer in which the inner coating layer and the outer coating layer whose physical properties change continuously are integrated, electron beam irradiation is applied to cure the recording layer, and then the molding surface is peeled from the recording layer. By satisfying the ink acceptability required for water-based ink recording sheets, the image quality is good and the gloss is high and the image quality is excellent even on paper substrates such as plain paper and coated paper, which are significantly inferior in texture to plastic films. The present invention has been completed based on the finding that a water-based ink recording image having properties can be obtained.

That is, the aqueous ink recording sheet according to the present invention comprises a sheet-shaped substrate, an inner coating layer formed on the sheet-shaped substrate, and an outer coating formed on the inner coating layer. When manufacturing a water-based ink recording sheet composed of a layer, an inner coating layer is formed by coating a coating liquid containing an unsaturated organic compound that can be cured by electron beam irradiation as a main component on one surface of a sheet-shaped substrate. Then, separately on a highly smooth molding surface, a coating solution containing a water-soluble or water-dispersible resin as a main component is applied, dried, and if necessary, irradiated with an electron beam to form an outer coating layer, The inner coating layer on the base material is superposed on the outer coating layer on the molding surface and pressure-bonded to form a recording layer in which the outer coating layer and the inner coating layer are integrated. After irradiating and curing the recording layer, peel off the recording layer from the high smooth molding surface. That it is characterized in that it comprises.

The base material used in the present invention includes high-quality paper,
Coated paper, synthetic paper, plastic sheets or laminated sheets combining them can be used,
Furthermore, for the purpose of controlling the adhesiveness to the recording layer and the penetration of the coating material for the inner coating layer into the substrate, a substrate having an undercoat layer made of a water-soluble or water-dispersible resin, a pigment, etc. It can also be used. The thickness of such a base material is not particularly limited, but in view of strength, workability, electron beam permeability, etc., 2
It is preferably from 0 to 250 μm, and its basis weight is preferably from 20 to 250 g / m ² .

The outer coating layer coating composition of the present invention has good ink receptivity, releasability that enables good transfer from the molding surface, and partially assists the crosslinked structure mainly obtained by the inner coating layer coating composition. Since the main component is a water-soluble or water-dispersible resin because it requires high gloss even after receiving the ink and gradual cross-linking property that enables maintaining excellent image clarity, a pigment, a cross-linking agent,
Various additives such as an ink fixing agent can be blended.

In the present invention, examples of the water-soluble and water-dispersible resin used in the coating material for the outer coating layer include polyvinyl alcohol, silanol-modified polyvinyl alcohol and other modified polyvinyl alcohol, starch, modified starch, and gum arabic. , Gelatin, casein, chitosan, methylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, polyvinylpyrrolidone, polyvinylpyrrolidone-vinyl acetate copolymer, polyacrylate, polyacrylic amide, polyester resin, styrene-acrylic acid ester copolymer resin, styrene- Water-soluble resins such as maleic anhydride copolymer resin, methyl vinyl ether-maleic anhydride copolymer resin, isopropylene-maleic anhydride copolymer resin, vinyl acetate emulsion, acrylate ester John, a methacrylic acid ester emulsion, a polyurethane emulsion, a polyvinyl chloride emulsion, an SBR latex, an MBR latex, etc., which are water-dispersible resins having a low minimum film-forming temperature and good film-forming property, alone or in a mixture. be able to. The content of the water-soluble or water-dispersible resin in the coating material for the outer coating layer is preferably 70% by weight or more of the total solid content. 70
If it is less than wt%, the desired ink acceptability cannot be obtained.

Further, in order to maintain high gloss and excellent image clarity of the recording layer even after receiving the ink, a crosslinking agent may be added to the coating material for the outer coating layer. For example, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, those curable by electron beam irradiation,
Various water-soluble acrylates such as ethylene oxide-modified bisphenol A diacrylate, methacrylate-based monomers, water-soluble monomers such as acryloylmorphine, N-vinylpyrrolidone, and polyurethane acrylate oligomers, polyurethane methacrylate oligomers, polyester acrylate oligomers, polyester methacrylate oligomers, etc. Water-soluble or water-dispersed oligomers modified with acrylates and methacrylates can be used. On the other hand, those which can be cured by heating include glyoxal, dialdehyde compounds such as polyaldehydes, polyamine resins such as polyethyleneimine, epoxy resins, polyamide resins, melamine resins, diglycidyl compounds such as glyceryl glycidyl ether, dimethylol urea. Compounds, aziridine compounds, block isocyanate compounds, and inorganic compounds such as ammonium persulfate, ferric chloride, magnesium chloride, sodium tetraborate and potassium tetraborate, or boric acid, boric acid triesters, boron compounds Polymers can be used. These crosslinking agents can be used in the range of 5 to 30% by weight based on the solid content of the coating material for the outer coating layer. If it is less than 5% by weight, it is impossible to maintain the high gloss and excellent image clarity of the recording layer even after receiving the ink, and if it is more than 30% by weight, the ink acceptability is deteriorated. Further, for the purpose of improving the gloss after receiving the ink and the excellent image clarity, it is also possible to apply the coating material for the outer coating layer and, after drying, perform electron beam irradiation in advance.

In order to improve the ink receptivity of the recording layer, or to adjust the color tone of the recording layer, a fine particle pigment may be added to the outer coating layer coating material. For example, fine particle synthetic silica, zeolite, calcium carbonate, magnesium carbonate, kaolin, clay, talc, calcined clay,
Diatomaceous earth, synthetic aluminum silicate, zinc oxide, titanium oxide, aluminum hydroxide, barium sulfate, inorganic pigments such as surface-treated calcium carbonate and silica, and urea-formalin resin, styrene-methacrylic acid copolymer resin, polystyrene Organic pigments such as resins can be used. The blending amount of these pigments can be used within the range of less than 30% by weight based on the solid content of the coating material for the outer coating layer. 30
When the content is more than 10% by weight, high gloss and excellent image clarity cannot be maintained after receiving the ink. Other additives include pigment dispersants, defoamers, antioxidants, ultraviolet absorbers, viscosity modifiers, and cationic compounds for improving the fixability of printed matter after inkjet recording. Used as appropriate according to quality and required performance.

The outer coating layer forming the recording layer of the present invention can be obtained by coating so that the coating amount after drying is 1.0 to 15.0 g / m ² . Coating amount is 15.0
If it exceeds g / m ² , it takes time for the coating material for the inner coating layer to permeate the outer coating layer after pressure bonding with the inner coating layer, and it takes time to affect the workability. When the coating amount is less than 1.0 g / m ² , it is difficult to obtain high glossiness and excellent image clarity in addition to poor releasability from the molding surface after electron beam irradiation and curing.

The coating composition for the inner coating layer of the present invention has an ink receptivity within a range that does not impair the ink receptivity of the outer coating layer, a high gloss after the ink reception, a crosslinked structure capable of maintaining excellent image clarity, and peeling from the molding surface. For this purpose, the main component is an unsaturated organic compound that can be cured by electron beam irradiation, which satisfies the adhesiveness with a base material and the penetrability that allows proper penetration into the outer coating layer after pressure bonding with the outer coating layer. In addition, various additives such as pigments and ink fixing agents can be added for the purpose of improving properties such as ink acceptability or for adjusting color tone.

The unsaturated organic compounds which can be cured by electron beam irradiation and are used for the inner coating layer constituting the recording layer of the present invention include the following systems, but from the viewpoint of ink acceptability,
Monomers and oligomers having water absorption or having many hydrophilic groups are preferable. (1) A system composed of at least one kind of monomers and oligomers having an acrylate group, a methacrylate group, etc., and a system in which the reaction proceeds by radical polymerization, and (2) a system composed of unsaturated polyester and a vinyl ether compound, in which the reaction proceeds by radical polymerization. , (3) a system composed of a polyene compound and a polythiol compound, which undergoes a reaction by radical polymerization, (4) a system composed of at least one or more of a vinyl ether compound and an epoxy resin and a cationic polymerization initiator, and a system in which a reaction proceeds by cationic polymerization, ( 5) A hybrid system comprising at least two of (1) to (4) can be used, and representative compounds are exemplified below. The monomer (1) having an acrylate group or a methacrylate group at a molecular end or a molecular side chain is not particularly limited, but a long chain such as lauryl (meth) acrylate or stearyl (meth) acrylate is used. Chain aliphatic acrylate or methacrylate, benzyl acrylate, 2-ethylhexyl acrylate,
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate
, Nonylphenoxyethyl acrylate, 3-phenoxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, cyclohexyl (meth)
Acrylate, N, N-dimethylaminoethyl (meth)
Acrylate, N, N-diethylaminoethyl (meth)
Acrylate, 2-methoxyethyl (meth) acrylate
, Butoxyethyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, or other acrylate or methacrylate, or a monomer having two or more ethylenically unsaturated bonds is hexanedio-
Ludia acrylate, nonanediolu diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate, tetraethylene glycol diacrylate
, Ethylene oxide-modified bisphenol A diacrylate, trimethylolpropane triacrylate,
Examples thereof include ethylene oxide-modified trimethylolpropane triacrylate, propylene oxide-modified trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, and pentaerythritol hexaacrylate.

The oligomer (1) having an acrylate group, a methacrylate group or the like at a molecular end or a molecular side chain is polyester (meth) acrylate, epoxy (meth) acrylate, polyurethane (meth) acrylate, polybutadiene (meth). Examples thereof include acrylate, acrylate, and methacrylate-modified dimethylpolysiloxane. In addition, as a compound which has an unsaturated double bond but has a special structure and can be used in the same manner, for example, monomers such as N-vinylpyrrolidone and acryloylmorpholine can be mentioned.

Examples of the unsaturated polyester compound (2) include unsaturated polyesters having maleic acid, fumaric acid and the like in the molecule. Examples of vinyl ether compounds include vinyl ether compounds such as triethylene glycol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, hydroxybutyl vinyl ether, dodecyl vinyl ether, and propenyl ether propylene carbonate.

Examples of the polyene compound of (3) include polyene compounds such as polyfunctional vinyl ether compounds having a bisphenol structure and polyfunctional propargyl compounds. Further, examples of the polythiol compound include polythiol compounds such as pentaerythritol tetrakis (2-mercaptoacetate) and m-xylene-α, α'-dithiol.

Examples of the epoxy resin (4) include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and bis- (3,4).
-Epoxycyclohexyl) adipate, vinylcyclohexene dioxide, alicyclic epoxy resin such as 1,2-epoxy-p-vinylcyclohexene, glycidyl ether compound such as bisphenol A diglycidyl ether, polypropylene glycol diglycidyl ether,
Examples thereof include epoxy resins having at least one oxirane ring in the molecule, such as diglycidyl ester compounds such as diglycidyl phthalate and diglyceryl dimer. Also, different from ethylene oxide, but having a similar oxirane ring, for example, 3-ethyl-
An oxetane compound having at least one oxytan ring in the molecule, such as 3-phenoxymethyloxetane, can be used as well. Examples of vinyl ether compounds include triethylene glycol divinyl ether and 1,4
-Vinyl ether compounds such as cyclohexane dimethanol divinyl ether, hydroxybutyl vinyl ether, dodecyl vinyl ether and propenyl ether propylene carbonate. As the cationic polymerization initiator used in the cationic polymerization system (4), diazoniums, sulfoniums, iodoniums, metal complexes and the like can be used.

Polymers soluble in these electron beam curable compositions of the present invention may be added in order to improve ink receptivity, but when the amount of the polymer is too large. It is not preferable because the crosslinked structure of the coating film or the adhesion to the substrate is reduced. Fine particle pigments can be used in the coating material for the inner coating layer in order to adjust the color tone of the recording layer. For example,
Inorganic pigments such as calcium carbonate, magnesium carbonate, kaolin, clay, talc, calcined clay, diatomaceous earth, synthetic aluminum silicate, zinc oxide, titanium oxide, aluminum hydroxide, barium sulfate, surface-treated calcium carbonate and silica. , And urea-formalin resin,
Organic pigments such as styrene-methacrylic acid copolymer resin and polystyrene resin can be used. The blending amount of these pigments can be used within the range of less than 50% by weight based on the solid content of the coating material for the inner coating layer.

To disperse the pigment in an unsaturated organic compound which is cured by electron beam irradiation, a three-roll mill, two-roll mill, cowles dissolver, homomixer, sand grinder, paint conditioner, ultrasonic disperser, etc. are used. can do. For the coating method of the inner and outer coating layers, use a method conventionally used by those skilled in the art such as an offset gravure method, an air knife method, a Mayer bar method, a blade method, a reverse roll method, and a slit die method. You can

When the viscosity of a coating composition in which a pigment is dispersed in a monomer or oligomer having an unsaturated bond which can be cured by electron beam irradiation is high, the coating solution may be diluted with an organic solvent and then dried, or the handling may be facilitated. In order to do so, it should be used by replacing it with an emulsified product or, if it is water-soluble, diluted with water, dried after coating, then pressure-bonded with the outer coating layer, integrated and then cured by electron beam. Is possible. As other additives, a pigment dispersant,
An antifoaming agent, an antioxidant, an ultraviolet absorber, a viscosity adjusting agent, a cationic resin for improving the fixability of the printed matter after inkjet recording, etc. are appropriately used according to the production conditions, the printing quality and the required performance. It

The inner coating layer forming the recording layer of the present invention has a coating amount of 1.0 to 3 after drying a coating material containing an unsaturated organic compound which is cured by electron beam irradiation as a main component.
It can be obtained by coating so that the amount becomes 0.0 g / m ² . If the coating amount exceeds 30.0 g / m ² , there is a drawback that the dimensional stability of the recording sheet decreases, and the coating amount is 1.0 g / m 2.
^If it is less than ² , the effect of the inner coating layer paint cannot be sufficiently reflected in the outer coating layer paint, and the peeling from the molding surface of the outer coating layer required for the inner coating layer paint and adhesion to the substrate Is difficult to achieve.

The method of the present invention will be described with reference to the drawings. 1 and 2 are schematic configuration diagrams of examples of devices that can be used in the present invention. In the configuration diagram shown in FIG. 1, a metallic cylindrical rotating body is used as a molding surface having high smoothness, and a coating material containing a water-soluble or water-dispersible resin for an outer coating layer as a main component is used for the rotating body. To form an outer coating layer on the rotating body in advance, and separately from this, a coating material containing as a main component an unsaturated organic compound that can be cured by electron beam irradiation to the sheet-shaped substrate. The inner coating layer is formed by coating, and the inner coating layer is pressure-bonded onto the outer coating layer on the rotating body to form an integrated recording layer, and the recording layer is subjected to electron beam irradiation. FIG. 4 shows the method of the present invention in which the recording layer obtained by curing is peeled off from the rotating body.

In FIG. 1, the first coating material 9 is contained in a first coating material container 8. The first coating material 9 is directed by an appropriate first coating device 10 such as an offset gravure coater in the direction of the arrow. The first coating layer 12 is formed by coating on the back surface of the sheet-shaped base material 11 that runs in the direction. Next, on the peripheral surface of the metallic cylindrical rotating body 5 of the curing equipment 1, the coating layer is formed, dried and pressure-bonded while the rotating body rotates in the direction of the arrow. A second member arranged so as to face the peripheral surface of the rotating body 5.
A second coating material 3 is contained in the coating material container 2, and the second coating material 3 is applied onto the molding surface of the rotating body by a second coating device 4 such as an offset gravure coater, and the second coating material 3 is applied. The work layer 7a is formed. This second coating layer 7a is dried by an infrared ray or / and hot air drying device 6'to form a second dry coating layer 7 '. Here, in the second dry coating layer 7 ', the first
The second cured coating layer 7b may be formed by irradiating an electron beam from the electron beam irradiation device 6 as needed. The second coating layer 7
a, the second dry coating layer 7'and the second cured coating layer 7b are collectively referred to as the second coating layer 7.

Next, the sheet-shaped base material 11 having the first coating layer 12 is guided to the guide roll 13 and is then rotated.
The first coating layer 12 is pressure-bonded onto the second coating layer 7 on the molding surface, which is also formed in advance, on the peripheral surface of the first coating layer 12 and the second coating layer. After being integrated with the layer 7, an electron beam is irradiated from the second electron beam irradiation device 14 through the on-sheet base material 11 to cure the recording layer. The water-based ink recording sheet 16 thus formed is peeled from the rotating body 5 by the peeling roll 15 and wound up.

In the method for producing a water-based ink recording sheet of the present invention shown in FIG. 2, one surface of the sheet-like material 17 running instead of the rotating body 5 of FIG. 1 is used as a molding surface to form an outer coating layer. Forming, drying and pressing are performed. In FIG. 2, the second coating material 3 in the second coating material container 2 is applied by the second coating device 4 onto one surface of the sheet-like material 17 traveling in the direction of the arrow, and the second coating material 3 is applied. The layer 7a is formed.
This second coating layer 7a is dried by an infrared ray or / and hot air drying device 6'to form a second dry coating layer 7 '. Here, the second dry coating layer 7'may be irradiated with an electron beam from the first electron beam irradiation device 6 as needed to form the second cured coating layer 7b. The second coating layer 7a, the second dry coating layer 7 ', and the second cured coating layer 7b will be collectively referred to as the second coating layer 7. The second coating layer 7 formed on the sheet-shaped material 17 is the first coating layer of the sheet-shaped substrate 11 formed by the guide roll 13.
The coating layer 12 is pressure-bonded and integrated, and an electron beam is irradiated from the second electron beam irradiation device 14 through the on-sheet material 17 to cure the integrated recording layer.

The aqueous ink recording layer 16 thus formed is peeled off from the sheet-like material 17 via the peeling roll 15 and wound up. When the sheet-shaped material is used as the molding surface, both the first electron beam irradiation device and the second electron beam irradiation device can be installed on the side opposite to the position shown in FIG. Further, it is necessary to set the peripheral speed of the metallic cylindrical rotating body 5 in FIG. 1 and the traveling speed of the sheet-shaped material 17 in FIG. 2 to be the same as the feeding speed of the sheet-shaped substrate 11. The metal cylindrical rotating body, although not particularly limited in its material and shape, stainless steel,
It is preferable to have a smooth peripheral surface that is mirror-finished with a material such as copper or chrome. Further, if necessary, a release agent such as silicone oil or wax may be applied in advance to the surface of the rotating body in order to facilitate the release of the cured recording layer.

The sheet material shown in FIG. 2 is not limited to its material and shape, but specifically, it has a high smooth surface such as a plastic sheet or a metal foil such as aluminum foil, and is relatively thick. A thin one is suitable. As the thickness increases, the flexibility becomes poor, and bending tends to occur during the pressure bonding and peeling processes. Further, if necessary, in order to facilitate the peeling of the cured recording layer, a release agent such as silicone oil or wax may be applied in advance on the surface of the rotating body. The sheet material may be processed into an endless belt and used.

The electron beam accelerator used for electron beam irradiation is not particularly limited in its system, and for example, an electron beam irradiation system such as an electron curtain system or a scanning system can be used. Among them, the electron-curtain system, which is relatively inexpensive and has a large output, is effectively used. Accelerating voltage during electron beam irradiation is 100
It is preferably KV or more, and the absorbed dose is preferably as small as possible within a sufficient range from the viewpoint of minimizing damage to the substrate. The outer coating layer and the inner coating layer of the present invention are pressure-bonded and integrated, and then cured by electron beam irradiation as a method of coating the outer coating layer on a highly smooth molding surface and the substrate. The inner coating layer is applied by pressure and cured by irradiating it with an electron beam from the opposite side of the water-based ink recording layer or from the molding side, and directly on the outer coating layer coated on the highly smooth molding surface. There is a method in which a coating material for the inner coating layer is applied, and thereafter, the coating material is pressure-bonded to the base material, and is irradiated with an electron beam from the opposite surface of the water-based ink recording layer or from the molding surface side to cure. The latter method can be carried out in the same manner as the former method, but the latter method differs from the former method in the permeability of the inner coating layer to the outer coating layer. It is necessary to adjust the pressure.

The surface of the recording layer formed as described above has high smoothness, high gloss and excellent image clarity.
Specifically, the 60-degree gloss specified by JIS-Z-8714 is 80% or more, and JIS-K-7105
When the value when the width of the optical comb is 2 mm is used as the scale of image clarity, the image sharpness defined by the above is preferably 80% or more, preferably 90%.

[0034]

The present invention will be described in more detail with reference to the following examples, but the invention is not limited thereto.

Example 1 A commercially available coated paper (manufactured by Shin-Oji Paper Co., Ltd., trademark: OK coat, basis weight: 127.9 g / m ² ) was coated with a coating of polyvinyl alcohol and clay at a coating amount of 1. bar as coating amount of the inner coating layer coating shown below on a blade coating the surface to be 5 g / m ² is 7.0 g / m ² - was coated by coating method, and this Separately, a 75 μm PET film (trade name: Lumira-T, manufactured by Toray) is coated with the following outer coating layer coating so that the coating amount after drying is 3.5 g / m ² and the outer coating layer is coated. To form a recording layer in which the outer coating layer and the inner coating layer are pressure-bonded together to form a recording layer, and an accelerating voltage of 175 KV is applied from the PET film side by an electron-caten type electron beam accelerator (manufactured by ESI). The recording layer is cured by irradiating an electron beam with an absorbed dose of 3.0 Mrad under the PET film. Allowed to obtain an aqueous ink recording sheet is peeled off after hardening PET film from the recording layer.

-Outer coating layer coating (solid content 10%) Polyvinyl alcohol aqueous solution (solid content 10%) (Nippon Synthetic Rubber, trademark: NM11Q) 45 parts by weight Polyethylene glycol (solid content 10%) (Sanyo Chemical Co., Ltd.) Trademark: PEG20000) 15 parts by weight Polyurethane acrylate emulsion (solid content 40%) (Mitsubishi Rayon, trademark: NR0289) 3 parts by weight Oxidized starch aqueous solution (solid content 10%) (Oji Constarch, trademark: Ace A) 5 parts by weight Part Fine particle silicic acid aqueous solution (solid content 10%) (Fuji Davison, trademark: Syloid) 25 parts by weight Water 6 parts by weight were mixed to obtain an outer coating layer coating material.

-Inner coating layer paint Polyurethane acrylate oligomer (Arakawa Chemical Co., Ltd., trademark: BS550) 20 parts by weight Ethylene oxide modified trimethylolpropane triacrylate (Daiichi Kogyo Seiyaku Co., Ltd., trademark TMP-3) 10 parts by weight Acryloylmorpholine 30 parts by weight ECH-modified 1,6 hexanediol diacrylate (Nippon Kayaku, trademark: R167) 20 parts by weight Titanium dioxide (Ishihara Sangyo, trademark: Taipaque A-220) 20 parts by weight, and mixed inside The coating layer was used as the coating material.

Example 2 Coating material for the inner coating layer shown below on one side of a substrate on which polyvinyl alcohol was size-pressed on a commercially available coated paper (trade name: OK coat, manufactured by Oji Paper Co., Ltd., basis weight: 127.9 g / m 2). Was coated by a bar coating method so that the coating amount was 6.0 g / m ^2, and the coating material for the outer coating layer shown below was dried on a highly smooth metal plate plated with chrome separately. Later coating amount is 4.0
The outer coating layer is formed by coating so as to be g / m ² , and the outer coating layer and the inner coating layer are pressure-bonded and integrated to form a recording layer. Accelerating voltage 1 from the substrate side with an electron-curtain type electron beam accelerator (manufactured by ESI)
The recording layer was cured by irradiating it with an electron beam having an absorbed dose of 3.0 Mrad below the inner coating layer at 75 KV, and after curing, the metal plate was peeled from the recording layer to obtain an aqueous ink recording sheet.

-Outer coating layer coating (solid content 15%) Polyvinyl alcohol aqueous solution (solid content 10%) (Nippon Synthetic Rubber, trademark: NM11Q) 45 parts by weight Polyvinyl alcohol aqueous solution (solid content 10%) (Nippon Gosei) Rubber, trademark: NL05) 5 parts by weight Glyoxal (solid content 30%) 4 parts by weight Polyethylene glycol (solid content 10%) (Sanyo Kasei, trademark: PEG20000) 10 parts by weight Polyvinylpyrrolidone aqueous solution (solid content 10%) ( BASF Corporation, trademark: K90) 30 parts by weight Water 6 parts by weight was mixed to obtain an outer coating layer coating material.

Inner coating layer coating urethane acrylate oligomer (manufactured by Daicel UCB, trademark: IRR143) 40 parts by weight acryloyl morpholine 50 parts by weight polyethylene glycol diacrylate (Daiichi Kogyo Seiyaku, trademark: PEG1000) 10 parts by weight The parts were mixed to form the inner coating layer paint.

Comparative Example 1 Using the same base material as in Example 1, the same inner coating layer coating material as in Example 1 was applied by a bar coating method so that the coating amount was 7.0 g / m ² . Electron-curtain type electron beam accelerator (ES
I), accelerating voltage of 175 KV, absorbed dose on the inner coating layer surface 3. The inner coating layer was cured by irradiation with an electron beam of 0 Mrad, and after curing, Example 1 was applied onto the cured inner coating layer.
Coating amount after drying the same outer coating layer coating as 3.5g / m
^A recording layer was formed by coating so as to have a thickness of ² to obtain a water-based ink recording sheet.

Comparative Example 2 The same base material as in Example 1 was used, and the same coating material for the outer coating layer as in Example 1 was applied by a bar coating method so that the coating amount after drying was 10.5 g / m ^2. A recording layer was formed by directly coating on the material to obtain a water-based ink recording sheet.

Comparative Example 3 The same coating composition for the outer coating layer as in Example 1 was applied onto one surface of a commercially available PET film (trade name: Lumirror T, manufactured by Toray, thickness: 75 μm), and the coating amount after drying was 10.5 g / m. Bar to ²
A coating layer was applied to form a recording layer to obtain a water-based ink recording sheet.

Gloss of the aqueous ink recording sheets obtained in Examples 1 and 2 and Comparative Examples 1 to 3, excellent image clarity and a commercially available ink jet printer (trade name BJC-8 manufactured by Canon Inc.).
20J), the gloss of a solid portion, excellent image clarity, ink absorbency, and water resistance were evaluated by the following methods. (1) Gloss For the solid part and the white paper part colored with yellow, magenta, and cyan color inks, the gloss meter is applied in accordance with the method of JIS-Z-8741 (specular gloss of 60 ° incident angle and 60 ° incident angle). -(Nippon Denshoku Industries Co., Ltd., VG-10) was used for measurement, and the measured values of 5 times were averaged. (2) Image clarity JIS-K-7105 is applied to solid portions and white paper portions that are colored with yellow, magenta, and cyan color inks.
In the image sharpness defined by, the value when the width of the optical comb of 2 mm was used was defined as the image clarity, and the values measured 5 times were averaged.

(3) Ink Absorbency The ink absorptivity was evaluated by measuring the number of seconds until the printed ink was dried and evaluated in three levels (◯: 5 seconds or less,
Δ: 6 to 10 seconds, ×: 11 seconds or more). (4) Water resistance In order to visually grasp the changes in gloss and image clarity before and after receiving ink, changes that appeared on the surface such as wrinkles, cracks, and floats after dropping water droplets and wiping were evaluated in three levels (○ : No change, Δ: slight change, ×: change).

The results are shown in Table 1.
No. 2 had good ink acceptability, almost no change in gloss and image quality before and after ink acceptance, and good water resistance and excellent photographic-like recorded image was obtained. Coating layer: When the coating material is dried, the surface property is reduced due to contraction of the substrate, so the gloss and image clarity before ink reception are low. Comparative Example 2 has no inner coating layer, and the influence of substrate contraction is larger than that of Comparative Example 1. In addition, since it has no water resistance, gloss and image clarity are further reduced. Further, in Comparative Example 3, since the plastic film is used as the substrate, there is no shrinkage during drying of the outer coating layer and gloss before ink reception and image clarity are high, but there is no water resistance and gloss before and after ink reception, Since the image clarity was greatly changed, a photographic recording image was not obtained, and although there was a difference in degree, it was significantly inferior to Examples 1 and 2 in any evaluation.

[0047]

[Table 1]

[0048]

As is clear from Table 1, by using the water-based ink recording sheet of the present invention, it is possible to obtain a recorded image having good ink acceptability, high gloss and excellent image clarity. It was That is, the water-based ink recording sheet and the method for producing the same according to the present invention are extremely useful in practice.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a process of using a metallic cylindrical rotating body for forming a recording layer of an aqueous ink recording sheet according to the present invention.

FIG. 2 is a schematic explanatory view of a process of using a sheet-like material for forming a recording layer of a water-based ink recording sheet according to the present invention.

[Sign explanation]

1 ... Manufacturing equipment, 2, 8 ... Paint container, 3 ... Second paint, 4 ...
Second coating device, 5 ... Metal cylindrical rotor, 6 ... First electron beam irradiation device, 6 '... Infrared ray or / and hot air drying device, 7
a ... 2nd coating layer, 7 '... 2nd dry coating layer, 7b ... 2nd hardening coating layer, 7 ... 2nd coating layer, 9 ... 1st coating material, 10 ... 1st
Coating device, 11 ... Sheet-shaped base material, 12 ... First coating layer, 1
3 ... Guide roll, 14 ... Second electron beam irradiation device, 15 ...
Release roll, 16 ... Water-based ink recording sheet, 17 ... Sheet material

Claims (1)

[Claims] 1. An aqueous ink recording sheet comprising a sheet-shaped substrate, an inner coating layer formed on the sheet-shaped substrate, and an outer coating layer formed on the inner coating layer. In doing so, an inner coating layer is formed by applying a coating liquid containing an unsaturated organic compound that can be cured by electron beam irradiation as a main component on one surface of the sheet-shaped substrate, and separately on a highly smooth molding surface. ,
Apply a coating solution containing a water-soluble or water-dispersible resin as a main component, dry it, and irradiate it with an electron beam to form an outer coating layer, if necessary, and form an outer coating layer on this molding surface. The inner coating layer on the substrate was overlaid and pressure-bonded to form a recording layer in which the outer coating layer and the inner coating layer were integrated, and electron beam irradiation was performed to cure the recording layer. After that, the method for producing an aqueous ink recording sheet, which comprises peeling off the recording layer from the highly smooth molding surface.