JP2001121813A - Ink jet recording adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording adhesive sheet having small curl after printing and excellent working suitability and quality. SOLUTION: In the ink jet recording adhesive sheet obtained by laminating an ink jet recording surface base material, an adhesive layer and a mold release sheet, a ratio of an MD direction tensile strength to a CD direction tensile strength measured according to a paper and cardboard tensile characteristic testing method in accordance with JIS P 8113 is 1.00 to 1.60. Further, the sheet also has a density of the release sheet measured according to a paper and cardboard thickness and density testing method in accordance with JIS P 8118 of 0.70 to 0.90 g/cm2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive sheet for ink-jet recording, and more particularly to a pressure-sensitive adhesive sheet for ink-jet recording which has no curl after printing with a printer and has excellent workability.

[0002]

2. Description of the Related Art Adhesive sheets for ink-jet recording are used as labels, stickers, stickers, patches and the like in a wide range of applications such as commercial use, office use, home use and the like. The pressure-sensitive adhesive sheet for ink-jet recording is generally formed by laminating a surface substrate for ink-jet recording, a pressure-sensitive adhesive layer, and a release paper in this order. Inkjet recording paper, glossy inkjet recording paper, super glossy inkjet recording paper, etc. are used for the surface substrate for inkjet recording, and release paper is used for release base paper such as high-density paper such as glassine paper, clay-coated paper, and polylaminate paper. Those coated with a release agent such as a silicone compound or a fluorine compound are used. Also,
Examples of the pressure-sensitive adhesive include a solvent-type pressure-sensitive adhesive, an emulsion-type pressure-sensitive adhesive, and a hot-melt-type pressure-sensitive adhesive.

[0003] The adhesive sheet for ink jet recording, which is such a laminate, tends to curl after printing, especially when the number of dots is large and the amount of ejected ink increases. The surface substrate for ink jet recording is finished to dry quickly so as to suppress bleeding of dots printed with an aqueous ink in order to obtain sharpness and color of an image. That is, after printing, the ink solvent contained in the ink passes through the ink receiving layer and is absorbed by the surface of the base paper and dried, and there are two types of escape methods: one that evaporates directly from the surface to the atmosphere and dries. The ink solvent passes through the ink receiving layer and is absorbed by the base paper surface,
During drying, the fibers shrink, and the ink jet recording surface substrate curls on the ink receiving layer application side.
Since the fiber expansion and contraction of the release paper does not occur, the ink-jet recording pressure-sensitive adhesive sheet largely curls on the surface substrate side due to the difference in the fiber expansion and contraction ratio between the surface substrate and the release paper.

Curling that occurs after printing on an ink-jet recording pressure-sensitive adhesive sheet is, for example, poor in paper feed or paper irregularities at the stage of processing the pressure-sensitive adhesive sheet for ink-jet recording into a label, a seal, etc. by performing die cutting (punching), sheet cutting, or the like. Cause trouble. For this reason, the occurrence of curl after printing on the pressure-sensitive adhesive sheet for ink jet recording becomes a very serious obstacle to workability and quality.

On the other hand, as a method for suppressing the occurrence of curling after printing on an ink-jet recording pressure-sensitive adhesive sheet, a method of humidifying the back surface of the release paper and allowing the same amount of solvent to escape from the release paper side as the surface base material. Has been proposed. However, in addition to the complexity of the equipment and the process, the effect is insufficient, and satisfactory results have not always been obtained.

[0006]

SUMMARY OF THE INVENTION In view of the circumstances described above, an object of the present invention is to provide a pressure-sensitive adhesive sheet for ink-jet recording which has very little curl after printing and is excellent in workability and quality.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a pressure-sensitive adhesive sheet for ink-jet recording comprising a surface substrate for ink-jet recording, a pressure-sensitive adhesive layer, and a release paper laminated on each other.
MD for tensile strength in the CD direction of the release paper measured by the test method for paper and paperboard-tensile properties specified in P-8113
A pressure-sensitive adhesive sheet for inkjet recording, wherein the ratio of the tensile strength in the direction is 1.00 to 1.60.

[0008] Further, the present invention relates to JIS-P-8118.
Paper and paperboard-Measured according to thickness and density test methods
The density of the release paper is 0.70 to 0.90 g / cm. ^Threeso
The above-mentioned adhesive for ink-jet recording characterized by having
It is a sheet.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the pressure-sensitive adhesive sheet for ink jet recording of the present invention, the ratio of tensile strength in the MD direction to tensile strength in the CD direction of release paper is important.
The ratio of MD tensile strength to MD tensile strength is 1.0
It must be between 0 and 1.60. The same ratio of commonly used release paper is 1.85 to 2.20.

If the ratio of the tensile strength in the MD direction to the tensile strength in the CD direction of the release paper exceeds 1.60, the tensile strength in the CD direction relative to the tensile strength in the MD direction is small, and the release paper curls in the CD direction. Easier to do. Accordingly, the ink jet recording pressure-sensitive adhesive sheet follows the CD curl of the surface base material generated after printing, and curls in the CD direction after printing.
Further, when the ratio of the tensile strength in the MD direction to the tensile strength in the CD direction of the release paper is less than 1.00, the operating conditions are significantly deteriorated, and it is difficult to prepare.

As the release paper of the present invention, high-density base paper such as glassine paper, clay-coated paper, kraft paper or woodfree paper or the like, for example, casein, dextrin, starch, carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxyethylcellulose, polyvinyl With natural or synthetic resins such as alcohols, styrene-butadiene copolymers, ethylene-vinyl chloride copolymers, methyl methacrylate-butadiene copolymers, ethylene-vinyl acetate copolymers, (meth) acrylate copolymers, etc. Emulsion-type, solvent-type or solvent-free silicone resin or fluorine on a base material provided with a filler layer containing a pigment as a main component, or poly-laminated paper made by laminating synthetic resin such as polyethylene on kraft paper or high-quality paper Dry weight of resin etc. is 0 After coated to about 05~3g / m ^2, made by forming a release layer is used suitably by heat curing or electron beam or ultraviolet curing or the like. The application device for applying the release agent is not particularly limited, but for example, a bar coater, a direct gravure coater, an offset gravure coater, an air knife coater, a multi-stage roll coater, or the like is appropriately used.

In particular, in order to make the ratio of the tensile elongation at break in the MD direction to the elongation at break in the MD direction 1.00 to 1.60, it is preferable to reduce the length / width ratio of the fiber orientation. Further, those having a density of 0.70 to 0.90 g / m ³ are preferable because the degree of freedom between fibers is large and fiber expansion and contraction due to environmental changes can be reduced. The density of the release paper is close to the density of the ink jet recording paper as the surface base material, and the fiber expansion and contraction ratio is also the same. Further, the release paper is laminated with a resin film such as polyethylene, a release paper coated with a hydrophobic and excellent film-forming coating material, or a resin-coated release paper on the back side, or bonded to hydroxyl groups of pulp fibers to increase hydrophilicity. Release paper that has been subjected to a one-sided or two-sided or impregnated treatment with a reducing surfactant or the like is also preferable because it is less susceptible to water absorption and dehydration due to environmental humidity changes and suppresses fiber expansion and contraction.

The ink receiving layer of the surface substrate for coating type ink jet recording of the present invention has its surface printed with ink by ink jet and contains an adhesive alone or an adhesive and a pigment. As the adhesive, polyester resin, polyurethane resin, polyacrylic resin, polyol resin, polyvinyl alcohol, polyvinylpyrrolidone, various cellulose derivatives, acetate resin, polyvinyl chloride resin, polyimide resin, various latex resins,
Examples include starch and derivatives thereof, gelatin, vegetable protein, casein, gum arabic, albumin, silica sol, alumina sol, zirconia sol, titania sol and the like. The adhesive may be used alone or in combination of two or more.

Examples of the pigment include an inorganic pigment and an organic pigment. As the inorganic pigment, for example, silica, clay,
Talc, kaolin, diatomaceous earth, aluminum hydroxide,
Examples include magnesium hydroxide, alumina, calcium carbonate, barium sulfate, titanium oxide, and zeolite.
Examples of the organic pigment include an ion exchange resin, a urea resin, a polystyrene resin, and a polyacrylic resin. The average particle size of the pigment is not particularly limited, but is usually 0.01 to 32 μm, preferably 0.01 to 32 μm.
22 μm. The pigment may be used singly, or 2
A combination of more than one species may be used. The mixing ratio of the adhesive and the pigment is not particularly limited, but is usually from 1: 0.02 to 1:15.
And preferably from 1: 0.1 to 1: 4. Various additives such as a dispersant, a leveling agent, an antioxidant, an ultraviolet absorber, a lubricant, and an antifoaming agent can be added to the ink receiving layer as needed. The thickness of the ink receiving layer is usually 3 to 80 μm, preferably 5 to 20 μm
It is. Although there is no particular limitation, the presence or absence of gloss on the coated surface is generally distinguished by whether or not the cast coat method is employed.

An acrylic resin, a natural rubber,
Rubber-based resins such as synthetic rubber are used.

Examples of the rubber resin include natural rubber, isoprene rubber, styrene / butadiene block copolymer, styrene / isoprene / styrene block copolymer, butyl rubber, styrene / ethylene / butylene / styrene copolymer, polyisobutylene, Examples thereof include polyvinyl isobutyl ether, chloroprene rubber, and nitrile rubber.

These rubber resins include natural resins such as rosin, modified rosin, rosin and modified rosin derivatives, polyterpene resins, modified terpene, aliphatic hydrocarbon resins, cyclopentadiene resins, and aromatic petroleum resins. resin,
Phenolic resin, alkyl-phenol-acetylene resin, cumarone-indene resin, vinyltoluene-α
-A tackifier such as methylstyrene copolymer and the like, various plasticizers, an antioxidant, a stabilizer, a softener such as oil, a filler, a stabilizer, a pigment, a colorant, and the like can be added as necessary. . These may be used in combination of two or more as necessary.

The acrylic resin is not particularly limited.
(a) alkyl group, (b) hydroxyl group, (c) epoxy group, (d) alkoxyl group, (e) ethylene oxide group,
(f) amino group, (g) amide group, (h) carboxyl group,
(i) a halogen atom, (j) a phosphate group, (k) a sulfonic group,
(l) silane group, (m) urethane group, (n) phenyl group,
Examples include those containing (o) a vinyl monomer having a benzyl group, (p) a tetrahydrofurfuryl group, and the like, and (q) other copolymerizable monomers.

(A) Examples of the vinyl monomer having an alkyl group include methyl (meth) acrylate and ethyl (meth) acrylate.
Acrylate, isopropyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isoamyl (meth) Acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, dodecyl (meth) acrylate, isobutyl (meth) acrylate and the like can be mentioned.

(B) Examples of the vinyl monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
-Hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxyethyl (meth) acrylate, and the like. (c) Examples of the vinyl monomer having an epoxy group include glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate.

(D) Examples of the vinyl monomer having an alkoxyl group include methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, and phenoxyethyl (meth) acrylate. (e) Examples of the vinyl monomer having an ethylene oxide group include diethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxydiethylene glycol (meth) acrylate,
Phenoxy polyethylene glycol (meth) acrylate and the like.

(F) As the vinyl monomer having an amino group, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N-ter
t-butylaminoethyl (meth) acrylate, methacryloyloxyethyltrimethylammonium chloride (meth) acrylate, and the like. (g) Examples of the vinyl monomer having an amide group include (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide,
N, N'-methylenebis (meth) acrylamide and the like.

(H) Examples of the vinyl monomer having a carboxyl group include acrylic acid, methacrylic acid, itaconic acid,
Maleic acid, fumaric acid, 2-methacryloyloxysuccinic acid, 2-methacryloyloxyethylmaleic acid,
2-methacryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl hexahydrophthalic acid and the like can be mentioned.

(I) The vinyl monomer having a halogen atom includes trifluoroethyl (meth) acrylate,
Pentadecafluorooxyethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2,3-
Examples thereof include dibromopropyl (meth) acrylate and tribromophenyl (meth) acrylate. (j) Examples of the vinyl monomer having a phosphate group include 2-methacryloyloxyethyldiphenyl phosphate (meth) acrylate, trimethacryloyloxyethyl phosphate (meth) acrylate, and triacryloyloxyethyl phosphate (meth) acrylate.

(K) Examples of the vinyl monomer having a sulfonic acid group include sodium sulfopropyl (meth) acrylate, sodium 2-sulfoethyl (meth) acrylate, sodium vinyl sulfonate, sodium styrene sulfonate, and 2-acrylamido-2-methyl. Sodium propanesulfonate, sodium 3-allyloxy-2-hydroxypropanesulfonate and the like can be mentioned.

(L) Vinyl monomers having a silane group include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethyl) silane,
Vinyl triacetyl silane, methacryloyloxypropyl trimethoxy silane and the like can be mentioned. (m) Examples of the vinyl monomer having a urethane group include urethane (meth) acrylate.

(N) As the vinyl monomer having a phenyl group, phenyl (meth) acrylate, p-tert
-Butylphenyl (meth) acrylate, o-biphenyl (meth) acrylate and the like. (o) Examples of the vinyl monomer having a benzyl group include benzyl (meth) acrylate.

(P) Examples of the vinyl monomer having a tetrahydrofurfuryl group include tetrahydrofurfuryl (meth) acrylate. (q) Other copolymerizable monomers include styrene, chlorostyrene, α-methylstyrene, vinyltoluene,
Vinyl chloride, vinyl acetate, vinyl propionate, Veo
va10 (manufactured by Shell Chemical Co., Ltd., vinyl alkylate compound), acrylonitrile, vinylpyridine and the like.

Also, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, 1,3 -Butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, divinylbenzene, N, N'-
Polyfunctional vinyl monomers such as methylenebisacrylamide, 1,4-butanediol di (meth) acrylate, and 1,6-hexanediol di (meth) acrylate can be copolymerized.

Further, in order to improve the adhesive properties of the acrylic resin, various additives such as natural resins such as rosin, modified rosin, rosin and derivatives of modified rosin, polyterpene resins, and terpene modified materials are used in the same manner as in the case of rubber resins. Body, aliphatic hydrocarbon resin, cyclopentadiene resin, aromatic petroleum resin, phenol resin, alkyl-phenol-acetylene resin, cumarone-indene resin, vinyltoluene-α-methylstyrene copolymer, etc. A tackifier, various plasticizers, an antioxidant, a stabilizer, a softener such as oil, a filler, a stabilizer, a colorant, a crosslinking agent, a pigment, and the like can be added as necessary. These may be used in combination of two or more as necessary. These acrylic resins are polymerized by any method such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization.

Examples of the crosslinking agent include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl-tris (2-hydroxyethyl) isocyanurate, and glycerol polyglycidyl ether. , Trimethylolpropane polyglycidyl ether, resorcin diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, bisphenol-S-diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, Propylene glycol diglycidyl ether, adipic acid diglycidyl ester, o- Diglycidyl ether tantalate, toluylene diisocyanate, 2,4-toluylene diisocyanate dimer, naphthylene-1,5-diisocyanate, o-toluylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate, tris- (p-isocyanate phenyl) Ions containing thiophosphite, polymethylene polyphenyl isocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, polyisocyanate prepolymer, Mg ²⁺ , Ca ²⁺ , Zn ²⁺ , Al ³⁺ And an acidic crosslinking agent (eg, zinc acetate, magnesium acetate, calcium acetate, etc.).

With respect to the method of forming the pressure-sensitive adhesive sheet for ink jet recording of the present invention, a pressure-sensitive adhesive is applied on the release layer surface of a release paper and dried if necessary to provide a pressure-sensitive adhesive layer. And the backside of the surface substrate for inkjet recording, or apply an adhesive on the backside of the surface substrate for inkjet recording, dry if necessary to provide an adhesive layer, and the adhesive layer and the release layer surface of the release paper And finished. In addition, as a device for applying the adhesive, for example, a reverse roll coater, a knife coater, a bar coater, a slot die coater, an air knife coater, a reverse gravure coater, a variogravure coater, or the like is appropriately used. The coating amount of the pressure-sensitive adhesive is adjusted in the range of 5 to 70 g / m ^{2 on} a dry weight basis. By the way, if it is less than 5 g / m ² , the pressure-sensitive adhesive performance of the obtained pressure-sensitive adhesive sheet for inkjet recording will be insufficient, while
If it exceeds m ² , the adhesive may protrude or cause cohesive failure at the time of peeling. More preferably 20 to
60 g / m ² . Even if it exceeds 60 g / m ² , no improvement is observed in the adhesive strength after application.

[0033]

The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted thereto. In the examples, the coating amount, the number of copies, the ratio, and the like are all based on the weight of the dry solid content unless otherwise specified.

Example 1 (Preparation of release paper) Each freeness was 490 ml.
LBKP of CSF (Canadian Standard Freeness, same hereafter)
80% and 20% NBKP with jet / wire ratio of 1.
00 become so after paper fine paper Beitsubo 110g / m ^2, a release agent eyes paints mainly composed of acrylic resin and pigment on one side 5.0 g / m ² was applied to obtain a release paper sheet . A 7% toluene solution of a thermosetting toluene-diluted release agent (trade name “KS-845”, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the obtained release paper base paper at 1.0 g / m 2 with a bar coater. ^The resultant was coated and dried to obtain a release paper of the present invention. The tensile strength in the CD direction of this release paper was 6.21.
kN / m, and the tensile strength in the MD direction is 6.74 kN / m.
Met. MD for tensile strength in the CD direction of this release paper
The ratio of the directional tensile strength was 1.08. The density of the release paper was 0.73 g / cm ³ .

(Preparation of Inkjet Recording Surface Substrate)
As a support, high-brightness wood pulp is used as a raw material, and a base paper having a basis weight of 77 g / m ^{2 is formed} , and then a coating liquid for an ink receiving layer having the following composition is applied to a dry weight of 15 g / m ^2. Then, the resultant was dried to obtain a surface substrate for ink jet recording. (Blending of ink receiving layer) Cationic resin: diallyl dimethyl quaternary ammonium hydrochloride aqueous solution (trade name: Unisense CP101, manufactured by Senka Co., Ltd.) 65 parts Ink absorbing pigment: amorphous silica (trade name: Fine Seal X-45, 100 parts Binder: polyvinyl alcohol (trade name: PVA10)
5, Kuraray Co., Ltd.) 200% aqueous solution with 10% solid content

The obtained release paper was coated with an acrylic emulsion-type pressure-sensitive adhesive (trade name: TS-662, manufactured by Nippon Carbide Co., Ltd.) at 23 g / m ² using a reverse roll coater and dried. The surface substrate for ink jet recording prepared as described above was bonded.

Example 2 (Preparation of release paper) Each freeness was 500 ml
90g of rice tsubo with 80% of CSF LBKP and 20% of NBKP
/ M ² high-quality paper was made such that the jet / wire ratio was 1.01, and 4.5 g / m ² of a release agent filling paint mainly composed of an acrylic resin and a pigment was applied to one surface thereof.
A release paper base paper was obtained. A heat-curable solvent-free release agent (trade name of addition reaction type: KNS-320) is applied to one side of the obtained release paper base paper.
: 100 parts of a trade name containing a platinum catalyst: PL-56
(Available from Shin-Etsu Chemical Co., Ltd.) was applied at 0.9 g / m ² using an offset gravure coater and dried with hot air to obtain a release paper of the present invention. The tensile strength in the CD direction of this release paper was 6.47 kN / m, and the tensile strength in the MD direction was 7.46 kN / m. The ratio of the tensile strength in the MD direction to the tensile strength in the CD direction of the release paper was 1.15. The density of the release paper was 0.83 g / cm ³ .

(Preparation of Inkjet Recording Surface Substrate)
As a support, a base paper having a basis weight of 64 g / m ^{2 made} of high-whiteness wood pulp was used, and a coating liquid for an ink receiving layer having the following composition was applied so that the dry weight was 13 g / m ^2. ,
It dried and the surface base material for inkjet recording was obtained. (Blending of ink receiving layer) Cationic resin: diallyl dimethyl quaternary ammonium hydrochloride aqueous solution (trade name: Unisense CP90, manufactured by SENKA) 65 parts Ink absorbing pigment: amorphous silica (trade name: Fine Seal X-45, 100 parts Binder: polyvinyl alcohol (trade name: PVA10)
5, Kuraray Co., Ltd.) 200% aqueous solution with 10% solid content

The obtained release paper was coated with an acrylic emulsion-type pressure-sensitive adhesive (trade name: TS-1189, manufactured by Nippon Carbide Co., Ltd.) at 25 g / m ² using a reverse roll coater and dried. The surface substrate for ink jet recording prepared as described above was bonded.

Example 3 (Preparation of release paper) Each freeness was 450 ml
Jet / jet with 70% LBKP and 30% NBKP of CSF
After paper fine paper Beitsubo 60 g / m ² as wire ratio is 0.99, the release agent eyes paints mainly composed of acrylic resin and pigment on one side 5.0 g / m ² was applied,
A release paper base paper was obtained. A thermosetting toluene-diluted release agent (trade name “KS-
845 "(manufactured by Shin-Etsu Chemical Co., Ltd.) in a 9% toluene solution using a bar coater so as to be 1.0 g / m ² and dried to obtain a release paper of the present invention. The tensile strength in the CD direction of this release paper was 5.95 kN / m, and the tensile strength in the MD direction was 8.83 kN / m. The ratio of the tensile strength in the MD direction to the tensile strength in the CD direction of the release paper was 1.48. The density of the release paper was 0.86 g / cm ³ .

Comparative Example 1 LBKP having a freeness of 300 ml · CSF
50% and 50% NBKP with a jet / wire ratio of 1.
After making high-quality paper of 62 g / m ² of rice tsubo to become 02,
A coating mainly composed of an acrylic resin and a pigment was applied at 5.0 g / m ² to one surface thereof, to obtain a base paper for release paper.

The surface of the obtained base paper for release paper coated with a release agent
Thermosetting toluene diluent release agent (trade name: KS-84)
5, Shin-Etsu Chemical Co., Ltd.)
1.0 g / m^TwoCoated and dried to make
A light release paper was obtained. The tensile strength of this release paper in the CD direction is
2.62 kN / m, and the tensile strength in the MD direction is 4.92.
kN / m. The tensile strength of this release paper in the CD direction is
The ratio of the tensile strength in the MD direction was 1.88. Ma
The density of the release paper was 0.85 g / cm. ^ThreeMet.

An acrylic emulsion-type pressure-sensitive adhesive (trade name: TS-662, manufactured by Nippon Carbide Co., Ltd.) was applied to the obtained release paper using a reverse roll coater so as to be 22 g / m ² and dried. The surface substrate for inkjet recording produced in the same manner as in Example 2 was bonded.

Comparative Example 2 LBKP having a freeness of 200 ml · CSF
20% and 80% NBKP with jet / wire ratio of 1.
After making glassine paper of 73 g / m ² in U.S.P. so as to obtain 03, polyvinyl alcohol was applied to both surfaces thereof at 2 g / m ² and subjected to a super calender treatment to obtain a base paper for release paper.

A release paper was obtained from the obtained release paper base paper in the same manner as in Example 2. The tensile strength in the CD direction of this release paper was 1.
75 kN / m and MD direction tensile strength of 4.06 kN
/ M. The ratio of the tensile strength in the MD direction to the tensile strength in the CD direction of the release paper was 2.31. The density of the release paper was 1.10 g / cm ³ . An acrylic emulsion-type pressure-sensitive adhesive (trade name: TS-662, manufactured by Nippon Carbide Co., Ltd.) was applied to the obtained release paper with a reverse roll coater so as to have a weight of 25 g / m ^2, and then dried. was changed to m ² is bonded to an ink jet recording surface substrate prepared in the same manner as in example 2.

With respect to the pressure-sensitive adhesive sheets for ink-jet recording obtained in Examples and Comparative Examples, the tensile strength of the release paper was measured under the following rules and conditions. It was shown to.

Elongation at break (kN / m): JIS-P-
8113 paper and paperboard-according to the tensile strength test method.

Curl evaluation: Using a color ink jet printer (MIJ-510C: manufactured by Epson Corporation), solid-color solid printing was performed, and the curl after natural drying was visually evaluated.
No curl, ；: Slight curl, but no problem; Δ: Curl, no problem,
X: It was determined that the occurrence of curling was remarkable.

[0049]

[Table 1]

As is clear from Table 1, the pressure-sensitive adhesive sheets for ink jet recording of Examples 1 to 3 according to the present invention are:
Although satisfactory results were obtained, the pressure-sensitive adhesive sheets for ink jet recording of Comparative Examples 1 and 2 were not satisfactory because they did not satisfy the required conditions.

[0051]

According to the present invention, the ratio of the tensile elongation at break in the CD direction to the elongation at break in the MD direction of the release paper, measured by the test method for tensile properties of paper and paperboard specified in JIS-P-8113, is 1.00 to 1.00. By controlling to be 1.60, more preferably, the density of the release paper measured by the test method of paper and paperboard-thickness and density specified in JIS-P-8118 is 0.70 to 0.70. By setting to 90 g / cm ³ , the occurrence of curl was effectively prevented.
An object of the present invention is to provide an excellent pressure-sensitive adhesive sheet for inkjet recording.

Claims (2)

[Claims] An ink-jet recording pressure-sensitive adhesive sheet comprising an ink-jet recording surface substrate, a pressure-sensitive adhesive layer, and a release paper laminated thereon, was measured by a paper and paperboard-tensile test method specified in JIS-P-8113. A pressure-sensitive adhesive sheet for inkjet recording, wherein the ratio of the tensile strength in the MD direction to the tensile strength in the CD direction of the release paper is 1.00 to 1.60. 2. The density of the release paper is 0.70 to 0.90 g / cm ³ , as measured by the thickness and density test methods for paper and paperboard specified in JIS-P-8118. The pressure-sensitive adhesive sheet for inkjet recording according to claim 1.