JPH082092A - Inkjet recording sheet for label and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] Ink jet recording sheet for labels, which suppresses ink bleeding caused by penetration of an adhesive into the ink receiving layer, does not deteriorate sharpness and color, and has good curling property. To get. [Structure] An inkjet recording sheet for a label in which an ink receiving layer is provided on one side of a support containing wood pulp as a main component and an adhesive layer is provided on the other side, and a barrier layer comprising a radiation curable resin and a radiation curable leveling agent is provided. An inkjet recording sheet for a label, which is provided on either or both of a support and the ink receiving layer or the adhesive layer, and a method for producing the same. [Effect] By the action of the radiation-curable resin and the radiation-curable leveling agent, the ink dots are not enlarged even if the adhesive layer is provided, and the ink receiving layer with few pinholes is obtained, and good ink jet recording is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording sheet for labels, and more specifically, it suppresses the bleeding of dots printed with a water-based ink to obtain good image sharpness and color. The present invention relates to an inkjet recording sheet for labels having good curl property.

[0002]

2. Description of the Related Art The ink jet recording system is a system for ejecting minute droplets of ink by various operating principles and adhering them to a recording sheet such as paper to record images, characters, etc., but at high speed and low noise. It is characterized by easy multicoloring, great flexibility in recording patterns, and no need for development-fixing, and is rapidly spreading in various applications as a recording device for various figures and color images including Chinese characters. Further, an image formed by a multicolor ink jet system can obtain a recording comparable to that of multicolor printing by a plate making system or printing by a color photographic system. Further, in applications requiring a small number of copies, it is being widely applied to the field of full-color image recording because it is cheaper than the photographic technique.

Further, with the diversification of needs, recording sheets printed by the ink jet recording system are used for price display labels, product display (bar code) labels, quality display labels, weighing display labels, advertisements. The use for labels such as labels (stickers) for use is increasing. In particular, the high sharpness of the inkjet sheet can be used for barcode labels, and for advertising labels,
Since it is excellent in sharpness and color, it is possible to obtain a good image, and the advertising effect is great. Further, it is possible to easily obtain an image excellent in image reproducibility and color reproducibility such as sharpness and color property at the personal computer level, which is also the reason why the inkjet recording sheet is frequently used. In particular, labels are used in many fields because they adhere well to a wide range of adherends and are easy to apply, and it is possible to obtain good characteristics of labels and good images on inkjet recording sheets. Applications that combine the features of being available are expanding. But,
Even when applied to labels, inkjet recording sheets for labels have no added value unless they are excellent in image reproducibility and color reproducibility, which are features of the inkjet recording system.

If an adhesive layer is provided as it is on an ink jet recording sheet obtained by the existing technique for label specification, the ink will seep out and the sharpness and colorability will be deteriorated due to the enlarged dot diameter. Image reproducibility is likely to deteriorate. For this reason, improvements have been made to the formulation of the coating composition for the ink-receiving layer, but the current situation is that this problem cannot be avoided. For this reason, the inkjet recording sheet for labels is required to have suppressed bleeding of dots, and further, with the recent visualization, the requirement for bleeding of ink has become quite strict. The current situation.

In the ink jet recording sheet for labels provided with an adhesive layer, the enlargement of the dot diameter in the ink receiving layer after printing varies depending on the type of adhesive used in the adhesive layer, but it is a solvent in the adhesive layer. Water or an organic solvent such as ethyl acetate or toluene, a relatively low molecular weight plasticizer, a component such as a surfactant penetrates through the support to the ink receiving layer, and further the component receives the ink from the ink receiving layer. It is considered that this is because ink bleeding occurs in order to change the ability and the fixing ability.

In order to prevent the penetration of the pressure-sensitive adhesive component into the ink receiving layer, a barrier layer made of a film-forming material is provided between the support and the ink receiving layer or the pressure-sensitive adhesive layer, or in both or both of them, a water-soluble polymer. Is proposed as a film forming material.
However, in the case of a water-soluble polymer, when forming a film on the support,
A drying process for volatilizing the solvent is required. Therefore, the support after coating the barrier layer may cause a slight decrease in smoothness and curl. If curling occurs on the support after coating the barrier layer, it becomes very delicate and difficult to adjust the curl balance when the ink receiving layer is provided. In addition, partial defects such as pinholes due to the volatilization of the solvent are likely to occur. Both the decrease in the smoothness of the support and the partial defect in the barrier layer deteriorate the ink jet recording property of the ink jet recording sheet.

[0007]

SUMMARY OF THE INVENTION Therefore, the problem to be solved by the present invention is to suppress bleeding of dots printed with a water-based ink in an inkjet recording sheet for labels, and to obtain good image sharpness and color. To obtain an inkjet recording sheet for a label having good curling property.

[0008]

The inventors of the present invention have made the following inventions as a result of earnest research for solving the above problems. That is, an ink receiving layer on one side of a support containing wood pulp as a main component, an inkjet recording sheet for a label provided with an adhesive layer on the other side, a barrier layer consisting of a radiation curable resin and a radiation curable leveling agent, The present invention is an inkjet recording sheet for a label, which is provided on at least one of a support and the ink receiving layer or between the support and the adhesive layer. The radiation-curable leveling agent is preferably a fluorine-containing compound such as a fluorine-containing acrylate or perfluoroalkyl acrylate, or a silicone-containing compound such as a silicone-containing acrylate or a derivative thereof.

The ink jet recording sheet for labels according to the present invention has an ink receiving layer on one side and an adhesive layer on the other side with a support interposed therebetween. The barrier layer of the present invention is provided between the support and the ink receiving layer, the support and the adhesive layer, the support and the ink receiving layer, and the support and the adhesive layer. In the inkjet recording sheet for labels of the present invention, the adhesive layer is used by being attached to a release paper.

The method for producing an ink-jet recording sheet for a label of the present invention is a radiation-curable composition containing a radiation-curable leveling agent on at least one of a support and an ink receiving layer or a support and an adhesive layer. Coating the resin
A barrier layer is formed by irradiating at least one of an electron beam and an ultraviolet ray to cure the radiation curable resin. In the method of the present invention, curling is less likely to occur and the smoothness of the support is less deteriorated than when a barrier layer made of an aqueous polymer is provided. This is a radiation-curable resin which is a solvent-free paint, requires no drying step when applied to a support, and hardly generates heat during film formation. Therefore, the solvent once soaked into the support does not volatilize again or remain slightly in the support,
It is also considered that the support is not overheated.

Further, it has been found that the use of the radiation curable resin in the barrier layer is unlikely to cause the enlargement of the ink dot diameter as compared with the case of using the water-soluble polymer in the barrier layer. This is because when a radiation-curable resin is provided in the barrier layer, the solvent does not pass through the support during curing to affect the fiber gap, and the solvent does not remain in the support, and It is thought that the permeation phenomenon of is suppressed.

In ink jet recording, partial defects such as pinholes generated in the ink receiving layer are fatal to obtain a high-definition image by ink jet recording, even if they are slight. I will end up. In the case of the solvent type coating liquid, since the partial defects are eliminated as much as possible, the coating amount is inevitably increased more than necessary, which is disadvantageous in terms of curl correction and cost. Further, in the curing process of the solvent type coating liquid, since the curing occurs from the surface of the coating layer or the interface with the support, the curing rate of the coating liquid in the depth direction of the coating layer is closer to the surface or the interface in the central part. It may be lower than the near part. As a result, the cohesive force of the barrier layer is weakened at the center, and when applied as a label, the label may be peeled off due to cohesive failure due to insufficient cohesive force of the barrier layer. If the drying conditions are stricter in order to avoid this with a solvent-type coating liquid, the pinholes in the barrier layer may increase, and if you try to dry more slowly to evenly cure in the depth direction, There was a problem that productivity would be extremely low.

The present inventors, as a barrier layer composition,
It has been found that these problems can be solved by using a mixture of a radiation curable resin and a radiation curable leveling agent. That is, the barrier layer composition of the present invention is applied without a solvent, and since a radiation-curable leveling agent is also used, partial defects such as pinholes caused by volatilization of the solvent during film formation. Rarely occurs. Further, by using a solventless radiation-curable resin and a radiation-curable leveling agent as a barrier layer composition, the leveling property of the resin will be good, so that the coating amount will be smaller than the solvent-type coating liquid, Easy curl control. Further, in the case of curing by radiation, since the penetrating power of radiation is very strong, it is possible to perform the curing uniformly in the depth direction, and the label peels without causing a difference in cohesive force or lack of cohesive force. It is possible to avoid the problem of "etc."

Further, although it was not expected at first, when a radiation-curable resin is mixed with a radiation-curable leveling agent, the ink-jet is more than when only the radiation-curable resin is used as the barrier layer composition. It was revealed that the rate of dot enlargement when recorded was small and good image forming ability was exhibited. In the present invention, when a leveling agent that is not radiation-curable is used, the coating suitability is good but the ink jet recording is not stable over time, and the ink dot system becomes thinner as time passes from the production. There may be problems. If a radiation curable leveling agent is used, it may be possible to fix the leveling agent at the same time when the barrier layer is cured.
Such changes over time are eliminated, and good inkjet recording properties can be maintained.

The radiation-curable resin forming the barrier layer in the present invention is not particularly limited as long as it forms a three-dimensional network structure after curing, and the curing method may be ultraviolet rays, electron beam irradiation alone, or Even by combination,
It may be used in combination with another polymerization method.

As the radiation curable resin, an unsaturated polyester having a radical polymerization curable functional group at a molecular end or a molecular side chain, a modified unsaturated polyester, an acrylic polymer and a polymer having an ethylenically unsaturated bond, and a monomer are used. Etc. can be used alone or with other solvents. For example, polyester polyacrylate, polyester polymethacrylate, polyurethane polyacrylate, polyurethane polymethacrylate, monofunctional acrylate, monofunctional methacrylate, vinylpyrrolidone, polyamide polyacrylate. Polyamide polymethacrylate, polysiloxane polyacrylate, oligoester modified products of these resins, alkylene oxide modified products and the like can be mentioned. These resins may be used alone or as a mixture.

The radiation-curable leveling agent used in the present invention comprises a fluorine-containing compound such as a fluorine-containing acrylate or perfluoroalkyl acrylate, a fluorine-containing methacrylate or a perfluoroalkyl methacrylate, a silicone-containing acrylate, a silicone-containing methacrylate or a derivative thereof. Examples thereof include silicone compounds, acrylate-modified hydrocarbon surfactants, methacrylate-modified hydrocarbon surfactants and the like.

The radiation curable leveling agents that can be used in the present invention are listed below. 1) Fluorine-containing acrylate or perfluoroalkyl acrylate (general formula; CH ₂ ═CHCOOC _n H _2n C _m F _2m H, CH ₂
= CHCOOC _n H _2n C _m F _{2m + 1} compound) 2,2,2-trifluoroethyl acrylate, 2,
2,3,3-tetrafluoropropyl acrylate, 1
H, 1H, 5H-octafluoropentyl acrylate, 1H, 1H, 2H, 2H-heptadecafluorodecyl acrylate, N- (n-propyl) -N- (β-acryloxyethyl) -perfluorooctyl sulfonic acid amide, Perfluoroalkyl ethyl acrylate etc. are mentioned. Trade names are VISCOAT 3F, VISCOAT 4F, VISCOAT 8F, VISCOAT 17F (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.), AE800, AE101.
4, Hoe T 3605 (manufactured by Hoechst Japan Ltd.) and the like.

2) Fluorine-containing methacrylate or perfluoroalkyl methacrylate (general formula; CH ₂ ═C (CH ₃ ) COOC _n H _2n C _m F
_2m H, a compound represented by CH ₂ = C (CH ₃ ) COOC _n H _2n C _m F _{2m + 1} . ) 2,2,2-trifluoroethyl methacrylate, 2,
2,3,3-tetrafluoropropyl methacrylate,
1H, 1H, 5H-octafluoropentyl methacrylate, 1H, 1H, 2H, 2H-heptadecafluorodecyl methacrylate, N- (n-propyl) -N- (β
-Methacryloxyethyl) -perfluorooctyl sulfonic acid amide, perfluoroalkyl ethyl acrylate and the like. The product name is Viscoat 4MF,
Viscoat 8MF, Viscoat 17MF (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.), MAE-600, MAE-1
014, MAE-800, Hoe T 3606 (manufactured by Hoechst Japan KK) and the like.

3) Silicone-containing acrylate, silicone-containing methacrylate or a derivative thereof A resin in which an acryloyl group or a methacryloyl group is introduced into the terminal or side chain of the molecular main chain of a general silicone resin (mainly polydimethylsiloxane) is a commercial product. The name is FM07
11, FM0721, FM0725, PS583 (above, manufactured by Chisso Corporation), KP-600, X-62-7.
140, X-62-7144, X-62-7153, X
-62-7153, X-62-7158, KNS-52
00, X-62-7166, X-62-7168, X-
62-7177, X-62-7180, X-62-71
80 (above, Shin-Etsu Chemical Co., Ltd.), RC149, RC
300, RC450, RC802, RC710, RC7
20 (above, manufactured by Gold Schmidt) and the like.

4) Acrylate-modified hydrocarbon-based surfactant, methacrylate-modified hydrocarbon-based surfactant Having an acryloyl group or methacryloyl group at the end or side chain of the hydrocarbon chain and a sulfonate at the other end or side chain. Alternatively, it is a surfactant having a phosphate functional group, and its trade names include H-3355N and H-3355S (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.).

The amount of the radiation-curable leveling agent added varies depending on the type of the radiation-curable resin, but is generally 0.001 to 25% by weight with respect to the radiation-curable resin.
Is. If the concentration of the radiation curable leveling agent is lower than this range, the expected leveling effect cannot be obtained, and if it is higher than this range, the dispersion of the leveling agent becomes poor.

The barrier layer is preferably provided on the basis of thickness, and the thickness of the barrier layer is 0.5 to 20 μm, although it must be varied depending on the roughness of the surface on which the barrier layer is provided and the coating or impregnation apparatus. Ranges are preferred. The thickness is 0.
If the thickness is less than 5 μm, the barrier layer may have some defects due to its leveling property even though it is a solvent-free type, and if it exceeds 20 μm, the effect for the purpose of the present invention does not change so much, which is uneconomical. It just becomes.

The method of applying the barrier layer of the present invention includes gravure coater, gravure offset coater,
Bar coater, roll coater, air knife coater,
U Comma Coater, AKUKU Coater, Smoothing Coater, Micro Gravure Coater, Reverse Roll Coater, 4 or 5 Roll Coater, Blade Coater, Dip Coater, Falling Curtain Coater, Slide Coater, Die Coater, etc. Good.

The electron beam irradiation used in the present invention has an accelerating voltage of 100 to 1000 KV, more preferably 100 to 300 KV in terms of penetrating power and hardening power, and more preferably 100 to 300 KV electron beam accelerator, and one-pass absorbed dose of 0. It is preferably set to 5 to 20 Mrad. If the accelerating voltage or the electron beam irradiation dose is lower than this range, the electron beam penetrating power is too low for sufficient curing, and if it is higher than this range, not only the energy efficiency deteriorates, but also the resin However, unfavorable effects on the quality such as the decomposition of additives and the deterioration of the strength of the base material appear.

The electron beam accelerator may be, for example, an electro curtain system, a scanning type, a double scanning type or the like.

During electron beam irradiation, if the oxygen concentration is high, the curing of the electron beam curable resin is hindered, so replacement with an inert gas such as nitrogen, helium, carbon dioxide, etc. is carried out, and the oxygen concentration is 600 ppm or less, Preferably 400 pp
Irradiation is preferably performed in an atmosphere suppressed to m or less.

In the present invention, the radiation-curable resin forming the barrier layer can be cured by irradiation with ultraviolet rays, if necessary. Examples of the ultraviolet irradiation device used include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, and a metal halide lamp, and there is also an ozoneless type that generates less ozone. Generally, a plurality of lamps having an output of 80 w / cm or more are used in parallel.

In the present invention, as the photoinitiator used for curing by ultraviolet irradiation, acetophenones such as di- and trichloroacetophenone, benzophenone, Michler's ketone, benzyl, benzoin, benzoin alkyl ether, benzyl dimethyl ketal, tetra There are methyl thiuram monosulfides, thioxanthones, azo compounds and the like, and they are selected from the viewpoints of the type of curing reaction of the curable resin, stability, suitability with an ultraviolet irradiation device, and the like. The amount of the photoinitiator used is usually in the range of 0.1 to 5% with respect to the ultraviolet curable resin. Further, a storage stabilizer such as hydroquinone may be used in combination with the photoinitiator.

The support according to the present invention means LBKP, NB
Chemical pulp such as KP, GP, PGW, RMP, TMP,
Mainly composed of mechanical pulp such as CTMP, CMP and CGP, and wood pulp such as waste paper pulp such as DIP, and conventionally known pigments, binders, sizing agents, fixing agents, yield improving agents, cationizing agents, paper strengthening agents. A raw paper produced by mixing with one or more kinds of various additives such as, and produced by various devices such as a Fourdrinier paper machine, a cylinder paper machine, and a twin wire paper machine.
Also included are coated papers such as art papers, coated papers and cast coated papers having a coat layer provided on these base papers. An ink receiving layer may be provided on the base paper and the coated paper as they are, or a calendering machine such as a machine calender, a TG calender or a soft calender may be used for the purpose of controlling the flatness.

The ink receiving layer according to the present invention comprises a coating composition containing a pigment and a binder as main components, and a dye fixing agent, a pigment dispersant, a thickener and a fluidity improving agent as additives to these. , Defoamer, foam suppressor, release agent, foaming agent, penetrant,
Coloring dyes, coloring pigments, optical brighteners, ultraviolet absorbers, antioxidants, preservatives, antifungal agents, water resistance agents, wet paper strength enhancers, dry paper strength enhancers and the like can also be appropriately added.

As the pigment used for the support and the ink receiving layer, one or more known white pigments can be used. For example, light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic non- Crystalline silica, colloidal silica, colloidal alumina, pseudo-boehmite, aluminum hydroxide, alumina, lithopone, zeolite,
White inorganic pigments such as hydrohaloysite, magnesium carbonate and magnesium hydroxide, organic pigments such as styrene plastic pigments, acrylic plastic pigments, polyethylene, microcapsules, urea resins and melamine resins can be used.

As the binder used in the support and the ink receiving layer, polyvinyl alcohol, vinyl acetate, oxidized starch, etherified starch, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, casein, gelatin, soybean protein, silyl modified. Polyvinyl alcohol, etc .; maleic anhydride resin, styrene-
Conjugated diene copolymer latex such as butadiene copolymer and methyl methacrylate-butadiene copolymer; polymer or copolymer of acrylic acid ester and methacrylic acid ester, polymer or copolymer of acrylic acid and methacrylic acid, etc. Acrylic polymer latex; vinyl polymer latex such as ethylene-vinyl acetate copolymer; or functional group-modified polymer latex with a functional group-containing monomer such as carboxyl group of these various polymers; melamine resin,
Water-based adhesives such as thermosetting synthetic resin-based adhesives such as urea resin; synthetic resin-based adhesives such as polymethylmethacrylate, polyurethane resin, unsaturated polyester resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, and alkyd resin. Used in one or more kinds.

As a coating or impregnating device for forming the ink receiving layer, various blade coaters, roll coaters, air knife coaters, bar coaters, rod blade coaters,
Various devices such as a curtain coater, a short dwell coater, a size press, and a spray can be used on-machine or off-machine. Further, after coating or impregnating each of the ink receiving layers, a machine calendar, a TG calendar,
It may be finished using a calendar such as a super calendar or a soft calendar.

The pressure-sensitive adhesive layer according to the present invention is provided with a pressure-sensitive adhesive on the release agent-coated surface of release paper described below, and the pressure-sensitive adhesive surface and the surface of the recording sheet on which the ink-receiving layer is not coated are stacked and pressed. Although a method of pressure bonding with a roll or the like is generally performed, an adhesive may be first applied to the recording sheet and then bonded to a release paper. A rubber-based or acrylic resin-based adhesive can be used as the adhesive. The main rubber-based raw material is natural rubber or styrene-butadiene rubber. In natural rubber, a rosin-based resin and a plasticizer are added, and normally hexane is used as a solvent for coating. When styrene / butadiene rubber is used as the main raw material, it is melted before coating.
The acrylic resin system is produced by polymerizing acrylic monomers such as 2-ethylhexyl acrylate, butyl acrylate, ethyl acrylate, acrylic acid and β-hydroxyethyl acrylate. Depending on the method of polymerization, an organic solvent such as ethyl acetate or toluene may be used, or an emulsion type polymerized while emulsifying in water with a surfactant may be used.

Further, in order to improve the physical properties such as heat resistance and solvent resistance of the pressure-sensitive adhesive, a crosslinking reaction may be carried out by using a crosslinking agent such as an isocyanate type, a melamine type or a metal chelate type in the above raw material. , Silica, kaolin, clay, calcium carbonate, aluminum hydroxide, zinc oxide, titanium oxide,
Addition of pigments such as melamine resin particles and starch particles, water-soluble polymers, petroleum-based resins, various paraffin waxes, fatty acids or their derivatives, higher alcohols, metal soaps,
Silicones, as well as antistatic agents, thickeners, dispersants, preservatives, antioxidants, defoamers and the like may be added. These pressure-sensitive adhesives may be selected according to the use of the inkjet recording sheet for labels.

The apparatus for providing the adhesive includes air knife coater, blade coater, bar coater, roll coater, slot nozzle, slot die, rotary screen printer, gravure coater, offset gravure coater, hot melt wheel, spiral sprayer, etc. Therefore, the type and amount of the adhesive, the necessity of imparting a pattern to the applied adhesive, and the like may be appropriately selected according to the application.

The ink jet recording sheet for labels of the present invention can be used together with release paper. As the base material of the release paper, there are high-quality paper, kraft paper, glassine paper, plastic film and the like, and a silicone resin is applied as a release agent on these base materials. In the case of paper-based substrate,
The peelability is improved when a thermoplastic resin is laminated on the base material to obtain a smooth surface. Directly coated silicone resin on paper base material is called direct type, laminated thermoplastic resin on paper base material is called poly-laminate type, directly applied on plastic film is called film type. The criteria for selecting a release paper from among the above are that the release paper has an adhesive force that does not peel off during transportation in the inkjet recording device, and that the adhesive force is less than or equal to the peeling force of the labeler when the label is attached by an automatic labeler. There is something. Therefore, it suffices to select a release paper suitable for the application. Further, when it is necessary to secure the curl aptitude, a thermoplastic resin is laminated on the opposite surface of the base material coated with the silicone resin as a back surface treatment. ,
It is preferable to coat with a synthetic resin. A non-silicone release agent may be used for special purposes.

The aqueous ink for ink jet recording referred to in the present invention is a recording liquid containing a colorant, a liquid medium, and other additives. Examples of the colorant include water-soluble dyes such as direct dyes, acid dyes, basic dyes, reactive dyes and food dyes.

As the solvent of the aqueous ink, water and various water-soluble organic solvents such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, C1-C4 alkyl alcohols such as isobutyl alcohol; amides such as dimethylformamide and dimethylacetamide; ketones or ketone alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyethylene glycol, polypropylene glycol Polyalkylene glycols such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hex Alkylene glycols having 2 to 6 alkylene groups such as len glycol and diethylene glycol; lower alkyl ethers of polyhydric alcohols such as glycerin, ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether and triethylene glycol monomethyl ether Can be mentioned. Among these many water-soluble organic solvents, polyhydric alcohols such as diethylene glycol and lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl ether and triethylene glycol monoethyl ether are preferable. Other additives include, for example, P
Examples include H regulators, sequestering agents, fungicides, viscosity regulators, surface tension regulators, wetting agents, surfactants, and rust inhibitors.

The ink jet recording sheet for labels in the present invention can be used not only as a label but also as an ordinary ink jet recording sheet, and can be used as any recording sheet using a liquid ink during recording. I don't care. For example, a heat-meltable ink containing a heat-meltable substance, a dye or pigment as a main component is a resin film,
A thermal transfer recording image receiving sheet that heats the ink sheet coated on a thin support such as high-density paper or synthetic paper from the back side to melt and transfer the ink, heat-melting ink melts by heating Inkjet recording sheet for recording and flying recording, inkjet recording sheet using ink in which oil-soluble dye is dissolved in solvent, photosensitive pressure-sensitive donor sheet using microcapsules containing photopolymerizable monomer and colorless or colored dye / pigment Corresponding image receiving sheets and the like can be mentioned.

The common point of these recording sheets is that the ink is in a liquid state at the time of recording. The liquid ink penetrates or spreads in the depth direction or the horizontal direction of the ink receiving layer of the recording sheet before being cured, solidified, or fixed. The various recording sheets described above require absorptivity according to their respective systems, and the inkjet recording sheet of the present invention may be used as the various recording sheets described above or the recording sheet for labels. In addition, copiers /
The inkjet recording sheet for labels of the present invention may be used as a recording sheet for heating and fixing toner of an electrophotographic recording system which is widely used in printers and the like, or a recording sheet for labels.

[0043]

In the ink jet recording sheet for labels of the present invention, a barrier layer comprising a radiation curable resin and a radiation curable leveling agent is provided at least between the support and the ink receiving layer or between the support and the adhesive layer. It is provided on one side. Since the radiation curable resin is a solvent-free coating liquid, a drying step is not required when it is applied to the support, and almost no heat is generated during film formation. Therefore, the solvent once soaked into the support does not volatilize again or remain slightly in the support, and the support is not excessively heated, which is advantageous for curl generation control. Furthermore, the decrease in the smoothness of the support is less than that of the water-soluble polymer. Moreover, since a radiation curable leveling agent is used,
Ink dots are not easily enlarged, dot reproducibility is good, partial defects such as pinholes are further reduced, and the coating amount of the barrier layer is smaller than that of the solvent type coating liquid.

[0044]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.
Further, “parts” and “%” shown in the examples represent parts by weight and% by weight, unless otherwise specified.

Example 1 The support was composed of light calcium carbonate / heavy calcium carbonate / talc based on 100 parts of wood pulp consisting of 70 parts of LBKP (freeness of 400 mlcsf) and 30 parts of NBKP (freeness of 450 mlcsf). 25 parts of a pigment having a ratio of 30/35/35, 0.10 part of a commercial alkyl ketene dimer,
After preparing 0.03 part of a commercially available cationic acrylamide, 1.0 part of a commercially available cationized starch, and 0.5 part of a sulfuric acid band, papermaking was carried out using a Fourdrinier paper machine at a basis weight of 70 g / m ² .

An ink receiving layer was provided on the surface of the manufactured support. As an ink receiving layer composition, 100 parts of synthetic amorphous silica (Fanseal X37B: manufactured by Tokuyama Soda Co., Ltd.),
Polyvinyl alcohol (PVA117: Kuraray Co., Ltd.) 3
0 parts, cationic dye fixing agent (Sumiraz resin 100
20 parts (manufactured by Sumitomo Chemical Co., Ltd.) was used to prepare a solution, and the solid concentration was 13%. Using the adjusted ink receiving layer coating liquid, dry coating amount of 5 with an air knife coater
It was coated on the surface of the support so as to be g / m ² .

As the radiation curable resin, an electron beam curable resin (Aronix M-24 manufactured by Toagosei Kagaku Kogyo Co., Ltd.) is used.
0) 100 parts and perfluoroalkyl ethyl acrylate (C ₈ F ₁₇ C ₂ H ₄ O as a radiation curable leveling agent)
0.1 part of COCH = CH ₂ ) was kneaded in an automatic mortar for 24 hours, and applied on the back surface of the support having the ink receiving layer so that the coating thickness was 4 μm, and at an acceleration voltage of 200 KV, 3 Mrad The resin was polymerized by irradiating it with an electron beam so that the absorbed dose was reached, and supercalendering was performed to form a barrier layer on the back surface of the support provided with the ink receiving layer.

Then, a commercially available water-based acrylic emulsion type pressure-sensitive adhesive (Arontuck HVC-3300 manufactured by Toagosei Chemical Industry Co., Ltd.) was applied to the release surface side of the commercially available release paper so that the dry coating amount was 20 g / m ^2. Then, the pressure-sensitive adhesive coated surface and the barrier layer were bonded together by a press roll to obtain an inkjet recording sheet for labels of Example 1.

Example 2 Example except that the radiation-curable resin was changed to O-tolyl acrylate, the radiation-curable leveling agent was changed to 1 part of polydimethylsiloxane tetraacrylate, and the coating thickness was 5 μm. In the same manner as in 1, an inkjet recording sheet for labels was obtained.

Example 3 A radiation curable resin was used as an ultraviolet ray curable urethane resin (Aronix UV3400 manufactured by Toagosei Kagaku Kogyo Co., Ltd.) 1
An ink jet recording sheet for labels was prepared in the same manner as in Example 1 except that the photoinitiator (Irgacure 651, manufactured by Ciba Geigy Co., Ltd.) was changed to 00 parts and 1% to the resin, and the electron beam irradiation was changed to ultraviolet irradiation. Obtained.

Example 4 A support was obtained in the same manner as in Example 1. As a radiation curable resin, 100 parts of electron beam curable resin (Aronix M-240 manufactured by Toagosei Chemical Industry Co., Ltd.) and as a radiation curable leveling agent, perfluoroalkylethyl acrylate (C8F17C2H4OCOCH = CH2) 0.
One part was kneaded in an automatic mortar for 24 hours, coated on one side of the support to a coating thickness of 2 μm, and irradiated with an electron beam at an accelerating voltage of 200 KV to an absorbed dose of 3 Mrad to polymerize the resin. Then, a barrier layer was provided on one surface of the support. An ink receiving layer was coated on the barrier layer under the same composition and coating conditions as in Example 1, and super calendar treatment was performed.
Then, the same silicone resin as in Example 1 was applied to the glassine paper with a gravure coater at 1.0 g / m ^2, and
The same pressure-sensitive adhesive as in Example 1 was applied to the silicone resin-coated surface so that the dry coating amount was 20 g / m ^2, and this pressure-sensitive adhesive-coated surface and the support surface not provided with the ink receiving layer were pasted with a press roll. In addition, an inkjet recording sheet for labels was obtained.

Example 5 A support was obtained in the same manner as in Example 1. The barrier layers were provided on both sides of the support so that the coating thickness was 2 μm. The barrier layer was formed by kneading 100 parts of O-tolyl acrylate as a radiation curable resin and 1 part of polydimethylsiloxane tetraacrylate as a radiation curable leveling agent in an automatic mortar for 24 hours. Was provided by a gravure coater, and the resin was polymerized by irradiation with an electron beam at an accelerating voltage of 200 KV and an absorbed dose of 3 Mrad in the same manner as in Example 1. afterwards,
The ink receiving layer was applied on one side under the same composition and coating conditions as in Example 1 and calendered. Then, the same silicone resin as in Example 1 was applied to the glassine paper with a gravure coater so as to be 1.0 g / m ² , and then the same adhesive as in Example 1 was applied to the silicone resin coated surface side in a dry coating amount of 20 g / m ^2. the coating is m ^2, and bonded to the surface of the adhesive coated surface and the ink receiving layer is not provided with a press roll to obtain a label for an ink jet recording sheet.

Comparative Example 1 A support and an ink receiving layer were obtained in the same manner as in Example 1. It was calendered without providing a barrier layer. Then, the same silicone resin as in Example 1 was applied to the glassine paper with a gravure coater so as to be 1.0 g / m ² and dried, and then the same adhesive as in Example 1 was dry coated on the silicone resin coated surface side. Quantity 2
It was coated at 0 g / m ² and dried, and the pressure-sensitive adhesive coated surface and the surface not provided with the ink receiving layer were bonded together by a press roll to obtain an inkjet recording sheet for labels.

Comparative Example 2 An electron beam curable resin (Aronix M-24, manufactured by Toagosei Kagaku Kogyo Co., Ltd.) was used as a radiation curable resin for the barrier layer.
An ink jet recording sheet for labels was obtained in the same manner as in Example 1 except that the ink jet recording sheet was composed of only 0).

Comparative Example 3 A support and an ink receiving layer were obtained in the same manner as in Example 1. The barrier layer was provided on the surface of the support opposite to the ink receiving layer. The barrier layer is a styrene-butadiene latex (062
3: manufactured by Japan Synthetic Rubber Co., Ltd.) and coated with an air knife coater on the back surface of the support provided with the ink receiving layer so that the thickness after drying is 4 μm, dried, and calendered. I went. Then, the same silicone resin as in Example 1 was applied to the glassine paper with a gravure coater so as to be 1.0 g / m ² and dried, and then the same adhesive as in Example 1 was dry coated on the silicone resin coated surface side. The amount of 20 g / m ² was applied and dried, and the pressure-sensitive adhesive coated surface and the barrier layer were bonded together by a press roll to obtain an inkjet recording sheet for labels.

Comparative Example 4 A radiation-curable leveling agent was used instead of a radiation-curable leveling agent (Sumitomo 3M Limited, Florard FC-
An inkjet recording sheet for labels was obtained in the same manner as in Example 1 except that the ink composition was changed to 430).

Comparative Example 5 A support was obtained in the same manner as in Example 1. The barrier layer was provided between the support and the ink receiving layer. The barrier layer was composed of polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.), was coated using an air knife coater so that the thickness after drying was 4 μm, was dried, and then was coated on the barrier layer. An ink receiving layer was applied under the same composition and coating conditions as in Example 1 and calendered. Example 1 was then applied to glassine paper.
The same silicone resin as in Example 1 was applied with a gravure coater to a concentration of 1.0 g / m ² and dried, and then the same adhesive as in Example 1 was applied to the silicone resin application surface side so that the dry coating amount was 20 g / m ^2. After coating and drying, the pressure-sensitive adhesive coated surface and the support surface on which the ink receiving layer is not provided were bonded with a press roll to obtain an inkjet recording sheet for labels.

Comparative Example 6 A support was obtained in the same manner as in Example 1. The barrier layers were provided on both sides of the support so that the thickness after drying was 2 μm. The barrier layer is polyvinyl alcohol (PVA
117: manufactured by Kuraray Co., Ltd.), each of the barrier layers was applied by an air knife coater, dried, and provided.
Thereafter, an ink receiving layer was applied on one side under the same composition and coating conditions as in Example 1, dried and then calendered. Then, the same silicone resin as in Example 1 was applied to the glassine paper with a gravure coater so as to be 1.0 g / m ² and dried, and then the same adhesive as in Example 1 was applied to the silicone resin coated surface side in a dry coating amount. It was coated at 20 g / m ² and dried, and the pressure-sensitive adhesive coated surface and the surface not provided with the ink receiving layer were bonded together with a press roll to obtain an inkjet recording sheet for labels.

The inkjet recording sheets for labels obtained in Examples 1 to 8 and Comparative Examples 1 to 3 were evaluated.

[Test Method] 1) Dot Enlargement Ratio The bleeding of ink caused by the provision of the adhesive layer was compared with the samples of the Examples and Comparative Examples in which the adhesive layer was not provided, and the labels provided with the adhesive layer. The dot diameter (Do) of the inkjet recording sheet for use and the dot diameter (Dn) of each inkjet recording sheet having no adhesive layer corresponding to each Example and Comparative Example were evaluated by the ratio (Do / Dn). If this ratio (dot expansion ratio: Do / Dn) exceeds 1.0, it means that the dots are enlarged, and if it exceeds 1.2, sharpness and chromaticity deterioration becomes clear, and subjective image It affects evaluation and becomes a problem. The dot diameter was the equivalent circle diameter defined by the following equation 1. Do and Dn were measured by leaving each sample in an environment of 20 ° C. and 65% RH for 24 hours to adjust the humidity, and then in an environment of an inkjet printer (I
O-720: manufactured by Sharp Corporation), dots are printed with black ink, and measurement is performed using an image analyzer.

[0061]

## EQU1 ## Di = {(4 / π) × Ai} ^1/2 where Di is the equivalent circle diameter (dot diameter), Ai is the measured area, and i is the adhesion corresponding to each Example and Comparative Example. This is a variable indicating the presence or absence of the agent layer (corresponding to i = 0 or i = n).

2) Curl property An inkjet recording sheet for labels, which was subjected to solid color solid printing of blue printing (cyan + magenta) using a Sharp (IO-720) inkjet printer, was 10 cm.
The sheet was cut in four directions, the glassine paper was peeled off under the conditions of 20 ° C. and 65% relative humidity, and the curl was measured by leaving it on a flat desk with the adhesive layer side up. The curl is represented by the average value of the lifting heights at the four corners. When the curl average value is less than 3 mm, the curl is excellent, and the curl of 3 mm to 7 mm is equal to the curl. Therefore, the curl was inferior.

3) Pinholes The presence or absence of pinholes was observed by visually observing a label inkjet recording sheet on which solid blue printing (cyan + magenta) was printed using a Sharp (IO-720) inkjet printer. It was confirmed. Those with no pinholes are good, and those with pinholes that do not seem to affect printing are the same as pinholes.
A pinhole having a pinhole that seems to have an influence on printing was judged to be poor.

[0064]

[Table 1]

[0065]

As is apparent from the above, according to the ink jet recording sheet for labels of the present invention, a barrier layer comprising a radiation curable resin and a radiation curable leveling agent is provided between the ink receiving layer and the adhesive layer. As a result, it is possible to obtain an ink jet recording sheet for labels with less ink bleeding and having good curl properties and without pinholes.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an inkjet recording sheet for labels in which a barrier layer is provided between an ink receiving layer and a support.

FIG. 2 is a cross-sectional view of an inkjet recording sheet for labels in which a barrier layer is provided between an adhesive layer and a support.

FIG. 3 is a cross-sectional view of an inkjet recording sheet for a label in which a barrier layer is provided between the ink receiving layer and the support and between the adhesive layer and the support.

[Explanation of symbols]

 1 Ink Receptive Layer 2 Barrier Layer 3 Support 4 Adhesive Layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G09F 3/02 F

Claims (5)

[Claims] 1. A label inkjet recording sheet having an ink-receiving layer on one side and an adhesive layer on the other side of a support containing wood pulp as a main component, and a barrier layer comprising a radiation-curable resin and a radiation-curable leveling agent. Is provided on at least one of the support and the ink receiving layer or between the support and the adhesive layer. 2. The inkjet recording sheet for labels according to claim 1, wherein the radiation-curable leveling agent is a fluorinated acrylate or a perfluoroalkyl acrylate. 3. The inkjet recording sheet for labels according to claim 1, wherein the radiation-curable leveling agent is a silicone-containing acrylate or a derivative thereof. 4. The inkjet recording sheet for labels according to claim 1, wherein the radiation is an electron beam or an ultraviolet ray. 5. A method for producing an inkjet recording sheet for a label, which comprises a radiation curable leveling agent at least one of a support and an ink receiving layer or a support and an adhesive layer. Apply resin,
A method for producing an inkjet recording sheet for a label, which comprises irradiating at least one of an electron beam and an ultraviolet ray to cure the radiation curable resin to form a barrier layer.