JP2003105288A - Pressure-sensitive adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive sheet which has excellent ink jet printability, especially scarcely causes a blotting of printed letters, is excellent in water resistance of the printed letters, and satisfies adhesivity and removability (property in which a pressure-sensitive adhesive surface can be adhered mutually with a strong pressure and, once it is peeled by hand, it does not adhere even if it is contact-bonded mutually) as paper for confidential postcards, or the like. SOLUTION: In the sheet having an adhesive layer on at least one side of a substrate sheet, wherein the layer can be adhered by subjecting themselves to a strong pressure treatment in a mutually faced state and the mutual layers can be peeled, it is characterized in that the layer contains an adhesive containing an acrylic resin which is obtained by copolymerizing two or more different acryl monomers in the presence of a water-soluble polymer, a compound having a cationic group and/or a functional group capable of becoming the cationic group and an adhesive power control agent.

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 used in various systems such as tri-fold or bi-fold postcards and cards.

[0002]

2. Description of the Related Art In recent years, with the revision of the Postal Law, a sheet on which necessary information is recorded is folded in two or three,
A postcard system with confidentiality has been put to practical use and is widely used.
The adhesive layer provided on the base sheet of the postcard having such confidentiality has no adhesiveness at room temperature and atmospheric pressure, and by applying pressure of about 500 Kg / cm ² with the adhesive layers facing each other. A pressure-sensitive adhesive sheet that exhibits adhesiveness and has an adhesive layer that can be peeled off after adhesion (hereinafter, also referred to as a representative example of postcard paper) is used.

Confidential postcard paper is printed on the adhesive layer with a standard item as a postcard, as described in JP-A-7-276858 and JP-A-9-71758, and then the address and personal information are printed on the same layer. The information to be concealed is printed with a laser printer, folded so that the adhesive layers face each other so that the concealed information cannot be seen from the outside, and pressure-laminated with a dry sealer to form a confidential postcard. The confidential postcard allows the recipient to see the information by peeling off the adhesive layer as it was originally. Once peeled off, the adhesive layer surface has no adhesiveness at room temperature and normal pressure, so it will be in the state before peeling. It is a postcard that should not be done.

Initially, the processing of the above-mentioned confidential postcard paper was carried out by a printing company having a comparatively large scale, by performing standard printing on the confidential postcard paper, printing information by a laser printer, pressure bonding with a dry sealer, and shipping. In recent years, the printing method is changing from a laser printer method to an inkjet printer method equipped with a drying facility capable of processing a large amount, and it is becoming possible for printing companies having a relatively small scale to do so.

The inkjet printer system is a system in which minute droplets of inkjet ink are ejected by various methods to be attached to a recording sheet such as paper to record images, characters and the like. Usually, the recording sheet has a high density of print dots, bright and vivid color tones, no color sink, and ink runs out or bleeds even when print dots overlap due to rapid ink absorption. First, there is a demand for less lateral diffusion.

Since an ink jet printer generally uses an anionic dye ink, when printing on a regular letter postcard, the water resistance of the printing is poor and the ink runs off with water. Therefore, in order to make the confidential postcard paper compatible with inkjet printing, an undercoat layer of a cationic compound may be provided between the base sheet and the adhesive layer, or the adhesive layer may contain a cationic colloidal silica or a cationic compound. However, it has been difficult to maintain the function of the adhesive layer and impart ink jet recording suitability.

Therefore, Japanese Patent Laid-Open No. 09-39378 proposes a pressure-sensitive adhesive sheet in which a quaternary ammonium salt or a cationic compound having a tertiary amino group is mixed in the pressure-sensitive adhesive layer. The cationic compound makes the pressure-sensitive adhesive contained in the adhesive unstable,
There is a problem such that sufficient adhesive force or removability cannot be obtained at the time of pressurization. Further, Japanese Patent Application Laid-Open No. 9-71758 proposes a pressure-sensitive adhesive sheet in which a pseudo-cationic adhesive is mixed with a weakly cationic polyamide resin. There is a problem that sufficient water resistance cannot be obtained.

It was thought that the above problem was solved by changing the recording ink to a pigment-based ink having water resistance, but the pigment-based ink has poor fluidity of the ink when high-speed printing is performed, and the dye-based ink is used. Since it dries relatively easily compared to ink,
There is a problem that nozzle clogging frequently occurs, and as a countermeasure against this, the line speed is 1/3 to 1% compared with dye-based ink.
Since it is printed at about 1/4 and the performance of a high-speed inkjet printer is not sufficiently exhibited, it is the current situation that it is not popular.

[0009]

DISCLOSURE OF THE INVENTION The object of the present invention is to have excellent suitability for ink jet printers, especially little bleeding of printing, excellent water resistance of printing, and adhesion and removability (sensitivity) as a postcard. It is an object to provide a pressure-sensitive adhesive sheet that can bond the pressure-bonded surfaces to each other with a strong pressure and that satisfies the characteristic that the pressure-bonded surfaces do not bond even if they are pressure-bonded after they have been separated by hand.

[0010]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have copolymerized two or more different acrylic monomers in the presence of a water-soluble polymer. By including an adhesive containing an acrylic resin, a compound having a cationic group and / or a functional group capable of becoming a cationic group, and an adhesive strength control agent, both inkjet suitability and adhesive suitability as a postcard paper were made compatible. A pressure sensitive adhesive sheet could be obtained.

The present invention includes the following aspects. [1] An adhesive layer is provided on at least one surface of a base sheet, and the adhesive layer can be adhered by performing high pressure treatment with the adhesive layers facing each other, and the adhesive layers are separated from each other. In a possible pressure-sensitive adhesive sheet, the adhesive layer contains an acrylic resin obtained by copolymerizing two or more different acrylic monomers in the presence of a water-soluble polymer, a cationic group and / or a cation. A pressure-sensitive adhesive sheet comprising a compound having a functional group capable of forming a base and an adhesive force control agent. It is preferable because it has good miscibility with a cationic compound and increases the ink jet printing density and printing water resistance. [2] The pressure-sensitive adhesive sheet described in [1], wherein the water-soluble polymer is polyvinyl alcohol. It is preferable because the ink jet printing density becomes high. [3] The pressure-sensitive adhesive sheet according to [1], wherein the water-soluble polymer is a resin having a cationic group and / or a functional group capable of forming a cationic group. Ink jet printing is preferable because it has high water resistance.

[4] The pressure-sensitive adhesive sheet according to [3], wherein the resin having a cationic group and / or a functional group capable of forming a cationic group is a copolymer of diallylamine hydrochloride and sulfone. Ink jet printing is preferable because it has high water resistance. [5] The pressure-sensitive adhesive sheet according to [1], wherein the water-soluble polymer is poly (2-hydroxyethyl methacrylate). It is preferable because the ink jet printing density becomes high. [6] The contact angle on the surface of the adhesive layer is 10 seconds after dropping water for 10 seconds.
The pressure-sensitive adhesive sheet according to any one of [1] to [5], which is 0 ° or less. It is preferable because the ink jet printing density becomes high.

[7] The compound having a cation group and / or a functional group capable of forming a cation group is at least one selected from compounds having a primary amino group or an addition salt thereof and a secondary amino group or an addition salt thereof. The pressure-sensitive adhesive sheet according to any one of [1] to [6]. Effective in improving print water resistance. [8] The feeling described in [7], wherein the compound having a cation group having a secondary amino group or an addition salt thereof and / or a functional group capable of becoming a cation group is a copolymer of diallylamine and acrylamide or an addition salt thereof. Pressure-bonded sheet. Effective in improving print water resistance and print non-transferability. In the present invention, the compound having a cation group and / or a functional group capable of forming a cation group (both of them are also referred to as a cationic compound) is an organic substance including a low molecular weight to a high molecular weight. In the present invention, the adhesive is a polymer resin that adheres the adhesive layers to each other.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The pressure-sensitive adhesive sheet used in the present invention is such that the adhesive layer provided on at least one surface of the base sheet does not exhibit adhesiveness at room temperature and normal pressure before being pressed,
And, with the adhesive layers facing each other, 500 kg /
It can be bonded by applying a pressure treatment to about cm ² , and the bonding surface has an adhesive layer that can be peeled by hand (this surface is also referred to as a re-peeling surface). Once peeled off, the adhesive layers do not adhere even if they are pressed together by hand. That is, only on one side of the substrate sheet, the adhesive layer surface having removability (hereinafter,
(Also referred to as a removable surface), a configuration in which an adhesive layer having removability (removable surface) is formed on both sides of the base sheet, and a removable adhesive layer (removable surface) on one side of the base sheet. A structure in which a peeling surface) is provided and the other surface is a non-removable surface (hereinafter also referred to as a permanent adhesive surface) is included.

Both the removable surface and the permanent adhesive surface are
It does not show adhesiveness at normal temperature and temperature, and it is 50 with dry sealer etc.
0 kg / cm²Degree (300 Kg / cm^Two~ 700Kg
/ Cm ^Two) Is adhered by pressure lamination.
Such an adhesive layer is a layer of adhesive and adhesive force control agent.
Adjust the adhesive strength by adjusting the total amount and coating amount. For example, re-peeling surface
After providing the information that needs to be hidden,
Fold the sheets or stack other sheets
The releasable adhesive layers so that they face each other.
Laminated sheet with information inside by pressure treatment
(For example, confidential postcards, lottery tickets, etc.).

Since the polymer resin conventionally used in the adhesive layer is usually anionic and the dye of the ink jet ink is also anionic, the adhesive resin cannot sufficiently retain the ink jet dye (usually in the ink). It is presumed that this causes the fixability, water resistance, and non-transferability of the dye (which causes mirror-like transfer to the adhesive layer surface on which printing is overlaid). Due to the anionic nature of the dye, it is necessary to add a cationic group and / or
Alternatively, it is effective to mix a compound having a functional group capable of forming a cation group, but the cation group and / or
Alternatively, an adhesive that does not cause aggregation when compounded with a compound having a functional group that can be a cationic group, that is, an adhesive that exhibits nonionic or cationic properties is required.

The present invention has an adhesive containing an acrylic resin obtained by copolymerizing two or more different acrylic monomers in the presence of a water-soluble polymer, a cation group and / or a functional group capable of becoming a cation group. The adhesive layer containing the compound and the adhesive strength control agent has a great feature.

Here, the adhesive must contain an acrylic resin obtained by copolymerizing two or more different acrylic monomers in the presence of a water-soluble polymer. Although the function of the water-soluble polymer is not always clear, it seems to act as a protective colloid. The water-soluble polymer used is not particularly limited as long as it is water-soluble, and a sulfonic acid group, a sulfonate,
Sulfate ester group, sulfate ester salt, carboxylate salt, quaternary ammonium group, carboxyl group, amino group, cyano group, hydroxyl group, amide group, imide group, ureido group, oxyethylene group, methoxy group, methoxymethyl group, methoxycarbonyl group Any polymer compound having at least one functional group selected from the groups may be used.

For example, (1) modified starch such as starch, oxidized starch, etherified starch, dialdehyde starch, esterified starch and the like (2) alginic acid compound such as sodium alginate and propylene glycol alginate (3) methyl cellulose, ethyl cellulose, Hydroxymethyl cellulose, hydroxyethyl cellulose,
Modified cellulose compounds such as carboxymethyl cellulose and carboxyethyl cellulose (4) Completely or partially saponified polyvinyl alcohol, modified polyvinyl alcohol (5) Others (casein, gelatin, pullulan, dextrin, polyethylene glycol, polyvinyl pyrrolidone, polyvinyl methyl ether, poly Acrylic acid, polyacrylamide, polyethyleneimine, polymaleic acid copolymer, poly (2-hydroxyethylmethacrylate), alkyd resin, cation group and / or resin having a functional group which can be a cation group, etc.) can be mentioned.

Among them, in the presence of polyvinyl alcohol, a resin having a cationic group and / or a functional group capable of forming a cationic group, and poly (2-hydroxyethyl methacrylate) having a relatively low molecular weight, two or more different acrylic resins are used. Polymerization stability during copolymerization of monomers is good, and water resistance and printing density of inkjet printing are also high, which is preferable. The reason why two or more different acrylic monomers are copolymerized is to adjust the glass transition point of the copolymer within an appropriate range and control its adhesiveness.

If the polyvinyl alcohol used as the water-soluble polymer is water-soluble, the average degree of polymerization and the degree of saponification are not limited. Further, thiol group modified polyvinyl alcohol, carboxyl group modified polyvinyl alcohol, sulfonic acid modified polyvinyl alcohol, silanol group modified polyvinyl alcohol, nitrile group modified polyvinyl alcohol, amide group modified polyvinyl alcohol, pyrrolidone modified polyvinyl alcohol, acetoacetyl group modified polyvinyl alcohol, Cation-modified polyvinyl alcohol, having 1 to 4 α-olefin units having 4 or less carbon atoms in the molecule
It may contain polyvinyl alcohol such as modified polyvinyl alcohol containing 20 mol%. Two or more of these polyvinyl alcohols may be used in combination. Also,
The amount of the water-soluble polymer such as polyvinyl alcohol used is 0.5 to 50% by mass of the total mass of the adhesive, preferably 1
Is about 30% by mass. When the amount of polyvinyl alcohol or the like used is less than 0.5% by mass, the polymerization may not proceed stably, and the stability of the resulting emulsion may not be obtained. That is, the viscosity may increase or aggregates may be generated. On the other hand, if it is more than 50% by mass, the viscosity of the polymerization system will be too high to allow the polymerization to proceed uniformly.

The resin having a water-soluble cationic group and / or a functional group capable of forming a cationic group used in the present invention includes polyvinylamine, polyallylamine hydrochloride, polyallylamine, allylamine hydrochloride-diallylamine hydrochloride copolymer. , Polydiallyldimethylammonium chloride, polydiallylmethylamine, diallyldimethylammonium chloride-sulfone copolymer, diallyldimethylammonium chloride-acrylamide copolymer, diallylamine hydrochloride-sulfone copolymer, diallylamine hydrochloride-maleic acid copolymer , Diallylamine hydrochloride-acrylamide copolymer, dicyandiamide-formaldehyde copolymer, dicyandiamide-ethyleneamine copolymer, vinyl imidazolium methacryl chloride-vinyl pyro Don copolymer, secondary amine - Ammonia - epihalohydrin reactant and the like, are suitably selected in consideration of the polymerization stability of the acrylic monomer. Further, two or more kinds of resins having these cationic groups and / or functional groups capable of forming cationic groups may be used in combination. The amount of the resin having a water-soluble cationic group and / or a functional group capable of becoming a cationic group is 0.5 to 15% by mass, preferably 2 to 12% by mass based on the total mass of the adhesive.
Is. Incidentally, when the amount of the water-soluble cationic resin used is less than 0.5% by mass, the polymerization may not proceed stably, and the stability of the resulting emulsion cannot be obtained. On the contrary, if it is more than 15% by mass, the viscosity of the polymerization system becomes too high, and there is a possibility that the polymerization cannot be progressed uniformly.

When poly (2-hydroxyethyl methacrylate) is used as the water-soluble polymer, it is necessary to properly adjust the degree of polymerization to make it water-soluble. In addition, poly (2
-Hydroxyethyl methacrylate) is used in an amount of 0.1 to 20% by mass, preferably 1 to 12% by mass based on the total mass of the adhesive. If the amount of polyhydroxyethyl methacrylate used is less than 0.1% by mass, the polymerization may not proceed stably, and the stability of the resulting emulsion may not be obtained. On the other hand, if it is more than 20% by mass, the viscosity of the polymerization system becomes too high, and there is a possibility that the polymerization cannot proceed uniformly.

In the present invention, a surfactant may be used in combination in order to improve the polymerization stability when the adhesive is polymerized. Examples of the surfactant used in combination include nonionic surfactants and cationic surfactants. Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene block polymers, polyoxyethylene alkylphenyl ethers, and surfactants having a hydrophilic group and a hydrophobic group. Examples thereof include nonionic reactive surfactants having a carbon double bond. Examples of the carbon-carbon double bond include functional groups such as (meth) allyl group, 1-propenyl group, 2-methyl-1-propenyl group, and (meth) acryloyl group. Specific examples of the reactive surfactant include, for example, polyoxyethylene alkyl ether having at least one functional group in the molecule, polyoxyethylene alkyl phenyl ether having at least one functional group in the molecule, Polyoxypropylene alkyl ether having at least one functional group in the molecule, polyoxypropylene alkylphenyl ether having at least one functional group in the molecule, polyoxyethylene polyoxy having at least one functional group in the molecule Propylene block copolymer alkyl ether, polyoxyethylene polyoxypropylene block copolymer alkylphenyl ether having at least one functional group in the molecule, polyoxyethylene polyoxy having at least one functional group in the molecule Propylene random copolymer alkyl ether, polyoxyethylene polyoxypropylene random copolymer alkyl phenyl ether having at least one said functional group in the molecule can be used. These nonionic surfactants can be used alone or in combination of two or more. The blending ratio of these nonionic surfactants in the adhesive is 0.01 to 5% by mass, preferably 0.05 to 2% by mass. Further, as the cationic surfactant, coconut amine acetate, alkylamine salts such as stearyl amine acetate, lauryl trimethyl ammonium chloride, stearyl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride, distearyl dimethyl ammonium chloride, alkylbenzyl dimethyl ammonium chloride. And quaternary ammonium salts such as
A mixture of two or more species can be used. The mixing ratio of these cationic surfactants in the adhesive is 0.01 to 5% by mass, preferably 0.05 to 2% by mass.

As the two or more different acrylic monomers (hereinafter also referred to as other monomer (* 1)) constituting the adhesive, an adhesive monomer is mixed as a main component with an aggregating monomer. Here, the tacky monomer means that the homopolymer derived from the monomer has a glass transition temperature of −20 ° C. or lower, and the lower limit is, for example, −100 ° C., in particular, butyl acrylate. , 2-ethylhexyl acrylate, ethyl acrylate, heptyl acrylate, hexyl acrylate, isobutyl acrylate, octyl acrylate, nonyl acrylate, -n-pentyl acrylate, lauryl acrylate, stearyl acrylate, propyl acrylate , Decyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, and the like, and butyl acrylate and 2-ethylhexyl acrylate are preferably used.

The cohesive monomer has a glass transition temperature of -20 ° C. or higher, preferably 0 ° C. or higher, for improving the cohesive strength of the adhesive, and the upper limit is, for example, 10
It may be 0 ° C. For example, methyl (meth) acrylate, ethyl methacrylate, propyl methacrylate, isopropyl (meth) acrylate, -n-butyl methacrylate, isobutyl methacrylate, -t-butyl (meth) acrylate, hexyl methacrylate, methacrylic acid. Octyl, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, styrene, α-methylstyrene, vinyltoluene, vinyl acetate , Vinyl propionate, vinyl versatate, allyl acetate, vinyl chloride, vinylidene chloride, (meth) acrylonitrile, (meth) acrylamide, N-methyl (meth) acrylamide, N-butoxymethyl (meth) acrylic acid , Diacetone (meth) acrylamide, (meth) acrylic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, 2-hydroxyethyl (meth) acrylate, 2-hydroxy-n-propyl (meth) acrylate, 2-hydroxyisopropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate,
Glycerol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, glycerin monoallyl ether, trimethylolpropane monoallyl ether, allyl alcohol, (meth) acrylic acid ester containing a primary amino group And addition salts thereof, (meth) acrylic acid ester containing a secondary amino group and addition salts thereof, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, (meth) N, N-dibutylaminoethyl acrylate, N, N-dimethylaminopropyl (meth) acrylate, N-methyl-N-ethylaminoethyl (meth) acrylate, N-ethyl-N-butyl (meth) acrylate Aminoethyl, (meth) a Acrylic acid N- ethyl -N- benzylamino ethyl, (meth) acrylic acid N, N- dimethylaminoethyl methyl chloride salt, (meth) acrylic acid N, N- dimethylaminoethyl benzyl chloride salt,
N, N-dimethylaminopropyl epichlorohydrin hydrochloride (meth) acrylate, 4-pyridylethyl (meth) acrylate, 4-pyridylpropyl (meth) acrylate, 4-pyridylbutyl (meth) acrylate, (meth)
Acrylic acid N-methylpyridinium chloride salt, (meth) acrylic acid N-ethylpyridinium bromide salt,
(Meth) acrylic acid N-ethylpyridinium chloride salt, (meth) acrylic acid N-propylpyridinium chloride salt, (meth) acrylic acid N-benzylpyridinium chloride salt, vinylpyridine, vinyl-N-methylpyridinium chloride salt, vinyl- Examples thereof include N-ethylpyridinium chloride salt and vinyl-N-phenylpyridinium chloride salt. The adhesive of the present invention is obtained by polymerizing the above-mentioned two types of acrylic monomers having glass transition points.

Here, in order to secure an appropriate adhesive force of the adhesive, the glass transition temperature is -100 ° C to 20 ° C, preferably -60 ° C by appropriately selecting the compounding ratio of the two or more different monomers. 20 ° C., more preferably −55 to −20
It is desirable to adjust the temperature to ° C. Glass transition temperature is -60 ℃
If it is lower, the adhesive strength becomes too strong and there is a risk of blocking. Further, when the glass transition temperature is higher than 20 ° C., the adhesive strength becomes too weak, and unintended peeling may occur during use as a tri-fold postcard or the like.

Next, the content of the adhesive in the adhesive layer on the removable surface is preferably about 10 to 40% by mass of solid content. If it is less than 10% by mass, the adhesive strength of the adhesive layer may be too weak, and if it exceeds 40% by mass, the pigment which is one kind of the adhesive force control agent in the adhesive layer may be coated and the ink absorption. Performance may be deteriorated, and inkjet suitability may be deteriorated. On the other hand, the amount of the adhesive compounded on the permanent adhesive surface is preferably about 40 to 70% by mass in terms of solid content. Incidentally, if it is less than 40% by mass, removability is exhibited, and if it exceeds 70% by mass, blocking tends to occur.

A polymerization initiator is preferably used in the polymerization of the acrylic monomer, and examples thereof include persulfates such as ammonium persulfate and potassium persulfate, and 2,2 ′.
Examples include azo compounds such as diamidino-2,2′-azopropane dihydrochloride and azobisisobutyronitrile, and peroxides such as di-t-butyl peroxide, cumene hydroperoxide, benzoyl peroxide and hydrogen peroxide. it can. Further, a known redox type initiator such as a combination of potassium persulfate and sodium bisulfite or a tertiary amine may be used. Polymerization is usually 10
~ 100 ° C, preferably 40 to 90 ° C, for about 3 to 20 hours. This polymerization reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen gas. The mixing ratio of the polymerization initiator in the adhesive is 0.1 to 5% by mass, preferably 0.2 to
It is 3% by mass.

When the adhesive used in the present invention is mixed with an adhesive strength control agent, a compound having a cationic group and / or a functional group capable of becoming a cationic group, and various additives,
The adhesive is preferably neutralized with an alkaline substance.
This makes it possible to prevent shock and thickening of the coating liquid when the pigment and the cationic resin are mixed. Examples of the alkaline substance used in the present invention include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, n-propylamine and di-amine.
n-propylamine, tri-n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, tert-butylamine,
Cyclohexylamine, benzylamine, α-phenylethylamine, β-phenylethylamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, tetramethylammonium hydroxide, aniline, methylaniline, dimethylaniline, diphenylamine,
Triphenylamine, o-toluidine, m-toluidine, p-toluidine, o-anisidine, m-anisidine, p-anisidine, o-chloroaniline, m-chloroaniline, p-chloroaniline, o-bromoaniline,
m-bromoaniline, p-bromoaniline, o-nitroaniline, m-nitroaniline, p-nitroaniline,
Various types of 2,4-dinitroaniline, 2,4,6-trinitroaniline, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, benzidine, morpholine, p-aminobenzoic acid, sulfanilic acid, sulfanilamide, etc. Primary amine, secondary amine, tertiary
Examples include primary amines. Among them, morpholine is preferable because it is excellent in the stability of the paint and the printing water resistance of the postcard.

In order to improve the water resistance of ink jet printing, the adhesive layer of the present invention needs to contain a compound having a cationic group and / or a functional group capable of forming a cationic group.

The compound having a cation group and / or a functional group capable of forming a cation group (that is, a cationic compound) used in the present invention is not particularly limited, and a primary amino group or an addition salt thereof and a secondary amino group. Or addition salts thereof, tertiary amino group or addition salts thereof, quaternary ammonium salt, primary amines of (meth) acrylic acid ester and addition salts thereof, diallylamine, diallylamine addition salts, secondary of (meth) acrylic acid ester Amines and addition salts thereof, tertiary amines of (meth) acrylic acid esters and addition salts thereof, quaternary ammonium salts of (meth) acrylic acid esters, pyridylalkyl esters of (meth) acrylic acid and pyridinium salts thereof,
Examples thereof include N-substituted pyridinium salts of (meth) acrylic acid pyridyl alkyl ester, vinylpyridines and pyridinium salts thereof. These are shown in Table 1.

[0033]

[Table 1]

Particularly preferred are compounds having a cation group having a primary amino group or an addition salt thereof and / or a secondary amino group or an addition salt thereof and / or a functional group capable of becoming a cation group. Monoallylamine, monoallylamine addition salts, primary amines of (meth) acrylic acid alkyl ester, primary amine addition salts of (meth) acrylic acid alkyl ester, derivatives containing primary amino groups derived from these compounds And oligomers and polymers containing these and / or diallylamine, diallylamine addition salts, secondary amines of (meth) acrylic acid alkyl ester, secondary amine addition salts of (meth) acrylic acid alkyl ester, and derivatives thereof And derivatives containing secondary amino groups, and oligomers and polymers containing them. Particularly preferred are copolymers of diallylamine and (meth) acrylic acid ester and addition salts thereof. Further preferred are copolymers of diallylamine and (meth) acrylamide and addition salts thereof. Incidentally, as the above-mentioned addition salts, hydrochloride,
Examples thereof include hydrobromide, hydroiodide, sulfonate, and p-toluenesulfonate.

When the compound having a cationic group and / or a functional group capable of becoming a cationic group is a polymer, the ratio of the cationic group and / or the monomer having a functional group capable of becoming a cationic group in the polymer is 10% by mass. % Or more, preferably 20% by mass or more. There is no particular upper limit, but it is about 80% by mass. The polymerization reaction is performed by adding the above-mentioned other monomer (* 1) to an aqueous solution containing the above-mentioned cationic group and / or a compound having a functional group capable of forming a cationic group.
Is continuously added. The addition speed may be constant speed or non-constant speed, and the addition time is usually in the range of 3 to 20 hours. In the polymerization reaction, the nonvolatile content is 1 to
It is preferable to set it to 80% by mass,
It is more preferable to set the content to be% by mass.

At the time of polymerization, it is preferable to use a polymerization initiator as in the case of polymerizing the adhesive. For example, persulfates such as ammonium persulfate and potassium persulfate, 2,2 ′.
Examples include azo compounds such as diamidino-2,2′-azopropane dihydrochloride and azobisisobutyronitrile, and peroxides such as di-t-butyl peroxide, cumene hydroperoxide, benzoyl peroxide and hydrogen peroxide. it can. Further, a known redox type initiator such as a combination of potassium persulfate and sodium bisulfite or a tertiary amine may be used. The polymerization initiator may be added to the aqueous solution containing the cationic compound in advance, or may be continuously added to the system simultaneously with the other monomer (* 1).

The polymerization is usually carried out at 10 to 100 ° C., preferably 40 to 90 ° C. for about 3 to 20 hours. This polymerization reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen gas. In the present invention, in carrying out such a polymerization reaction, it is preferable to allow hypophosphorous acid or a salt thereof to be present as a polymerization degree adjusting agent in the reaction system. Hypophosphorous acid is HPH
_It is a monobasic acid represented by ₂ O ₂ , and in addition to the free acid, sodium salt, lithium salt, potassium salt, ammonium salt, amine salt and the like can be used. It may be a hydrate. These hypophosphorous acids and salts thereof may be used alone or in combination of two or more.

The amount of hypophosphorous acid or its salt used is 0.01 to 3 based on the total number of moles of the monomers used.
The range of mol% is preferable, and 0.02 to 2 mol% is more preferable.
Is more preferable. When adding hypophosphorous acid or a salt thereof, it may be added in advance to an aqueous solution containing a cationic compound as in the case of the polymerization initiator, or it may be continuously added simultaneously with the other monomer (* 1). It may be added to the system.

Further, in the polymerization reaction of the present invention, a chelating agent such as ethylenediaminetetraacetic acid, hydroxyethylethylenediaminetriacetic acid, hydroxyethylethylenediaminediacetic acid or the like, or an alkali metal salt or ammonium salt thereof may be used if necessary. it can.
That is, when a metal ion, particularly a transition metal ion, coexists or mixes in the polymerization system, these ions cause an undesired decrease in viscosity of the water-soluble copolymer to be obtained, and therefore the purpose of excluding such an inhibitory factor is Therefore, it is also effective to add a chelating agent into the polymerization system.

When a chelating agent is used, the amount used is not particularly limited, but in order to exert its effect effectively, it is 50 ppm based on the total weight of the monomers used.
It is preferable to use the above. The upper limit of the amount of the chelating agent is arbitrary, and a considerable amount can be used within a range that does not cause adverse effects. However, in view of economy and the like, up to about 5000 ppm is sufficient based on the total weight of the monomers used.

When a chelating agent is used, it may be added in advance to an aqueous solution containing a cationic compound, like the polymerization initiator, hypophosphorous acid or its salt, or the other monomer (* 1). At the same time, it may be continuously added to the system. The preferred form of the cationic compound may be a solution such as an organic solvent solution or an aqueous solution, or may be an aqueous emulsion form.

The amount of the cationic compound used in the present invention is preferably 1 to 40% by mass, more preferably 3 to 30% by mass, based on the solid content of the adhesive layer. By the way, if the blending amount is less than 1% by mass, the adhesive force will be too strong, and after ink jet printing, pressure bonding and re-peeling will transfer the print to the non-printed surface, and the water resistance and ink absorption will be insufficient. There is a risk of disappearing, if the compounding amount exceeds 40 mass%,
There is a possibility that the adhesive strength at the time of pressure treatment may be lowered, the function as a pressure-sensitive adhesive sheet may be impaired, and the adhesiveness of printing and the water resistance of printing may be deteriorated.

As the adhesive force control agent, inorganic and organic pigments can be used. For example, zinc oxide, titanium oxide, zeolite, calcium carbonate, clay, aluminum oxide, wheat starch (non-gelatinized), silica,
Alumina, γ-alumina, colloidal silica, plastic pigments, polyethylene resin, polypropylene resin, fluorine resin and the like can be mentioned.

Among them, wheat starch is suitable for controlling the adhesive strength and is used as a spacer for the purpose of preventing blocking. Silica is preferable because it has excellent ink receptivity and improves printability and ink jet recording suitability (printing density). The fluororesin has a high effect of preventing ink bleeding. Further, titanium oxide has a high hiding effect, and when it is mixed with silica, the hiding effect is further enhanced. The adhesive force control agent is preferably used in combination with such an inorganic pigment or an organic pigment. The particle size of the inorganic pigment or organic pigment is preferably about 1 to 50 μm. The adhesive force control agent has an effect of adjusting so that the adhesive layer surface adheres under pressure and does not adhere after peeling once.

A binder resin may be added in order to improve the adhesion between the base sheet and the adhesive layer. Here, the binder resin is not particularly limited, but styrene-butadiene copolymer, styrene-butadiene-
Acrylic ester copolymer, acrylic ester copolymer, ethylene-vinyl acetate copolymer, starches such as oxidized starch (gelatinized), carboxymethyl cellulose, casein, dextrin, polyvinyl alcohol, modified polyvinyl alcohol, polyethylene Examples thereof include glycol, polyvinylpyrrolidone, polyvinyl methyl ether, polyacrylic acid, polyacrylamide, alkyl acrylate-based copolymers and urethane-based copolymers. When an anionic component is removed from the adhesive layer to improve inkjet suitability, the adhesiveness between the base sheet and the adhesive layer deteriorates, but a cation group and / or a cation group is present in one molecule. Adhesion can be improved by blending an amphoteric resin having a functional group capable of forming and an anion group and / or a functional group capable of forming an anionic group as a binder.

The pressure-sensitive adhesive sheet of the present invention coated with the above-mentioned adhesive layer preferably has a contact angle of 100 ° or less after 10 seconds from dropping water on the surface of the adhesive layer. Incidentally, if the contact angle exceeds 100 °, the wetting of the ink used in the inkjet printer becomes poor, the ink dots do not spread, and the print density decreases. The contact angle is preferably 95 ° or less, more preferably 90 ° or less, and the lower limit is not particularly limited, but 10 ° or more is preferable. As a method of adjusting the contact angle, there are appropriate adjustments of the types of adhesives, cationic compounds, adhesion control agents and the like, compounding amounts, coating amounts, drying conditions, and surface smoothness within appropriate ranges. In particular, imparting hydrophilicity to the adhesive resin, for example, increasing the amount of a water-soluble polymer used in the polymerization or increasing the copolymerization ratio of a monomer having a hydroxyl group and further having a polymerizable group In addition, the contact angle can be decreased and the printing density can be increased by increasing the compounding amount of the cationic compound, which is preferable.

In the adhesive layer, pigment dispersants, thickeners, fluidity improvers, defoamers, foam suppressors, release agents, wetting agents, penetrants, coloring dyes, and ultraviolet absorbers are added as additives. Agents, antistatic agents, cationic, nonionic or amphoteric surfactants, antioxidants, preservatives, water resistant agents and the like may be used.

The base sheet used in the present invention is not particularly limited, but may include high-quality paper, medium-quality paper, art paper,
Paper such as coated paper, synthetic paper, synthetic resin film, metal foil, non-woven fabric and the like may be used, and these may be laminated or surface-treated. Among them, papers are inexpensive and are preferably used. Of course, the papers may contain waste paper pulp, and the papermaking method and the like are not particularly limited.

In the winding after coating the adhesive layer, the JAPAN TAPPI paper pulp test method N
o. Standard deviation of roll hardness specified by 37-81 method is 5K
It is preferably gf · m or less. If the maximum value of the standard deviation of the winding hardness exceeds 5 Kgf · m, unnecessary deformation of the paper will occur when the adhesive layer is applied, and the size of the paper will be different between the left and right. High-speed printing using a form printing machine may cause troubles such as wrinkles and misregistration.

When the adhesive layer coating material is applied to the surface of the substrate sheet, the application method is not particularly limited, but various blade coaters, roll coaters, air knife coaters, bar coaters, gravure coaters, die coaters, A curtain coater or the like is used. Among these, air knife coaters, bar coaters, gravure coaters and the like are preferable. The coating amount is ^{2 to} 30 g / m ²
However, it is preferably in the range of ^{3 to} 15 g / m ² .

[0051]

EXAMPLES Examples of the present invention will be described below.
The invention is not limited to these examples. "Parts" and "%" shown in the examples are parts by mass and% by mass unless otherwise specified.

Example 1 [Formation of Removable Adhesive Layer] Fine paper 127.0 g / m ²
(Sunbird NDK-N <110>, manufactured by Oji Paper Co., Ltd.), one side of which was coated with a paint for re-peeling surface having the following composition by a Meyer bar at a solid content of 10 g / m ² and then dried by a hot air drier 10
It was dried at a temperature of 0 ° C. for 1 minute. "Removable surface coating composition" compounding amount An acrylic adhesive obtained by copolymerizing 78% ethyl acrylate and 22% butyl acrylate in the presence of polyvinyl alcohol (Polysol OLZ-1103-7, manufactured by Showa Polymer Co., Ltd., Nonionic adhesive, glass transition temperature -30 ° C) 12 parts by mass, copolymer of diallylamine hydrochloride and acrylamide, which is a resin containing a hydrochloride of a secondary amino group (Sumiraz Resin 1001, manufactured by Sumitomo Chemical Co., Ltd., Compound having cation group) 7 parts by mass, ethylene-vinyl acetate copolymer (Polysol OLY-3597, manufactured by Showa Highpolymer Co., nonionic binder) 20 parts by mass, wheat starch (AS-225, manufactured by Chiba Starch Co., paste) Unmodified starch) 6.5 parts by mass, precipitating synthetic silica (Mizukasil P-526, manufactured by Mizusawa Chemical Industry Co., Ltd.) 45 parts by mass, Ranol group-modified polyvinyl alcohol (PVA R-1130, manufactured by Kuraray Co., Ltd., nonionic binder) 9. 5 parts by mass, auxiliaries (dispersant, lubricant, defoaming agent, wetting agent) 4 parts by mass.

[Formation of Permanently-Adhesive Adhesive Layer] On the opposite surface of the high-quality paper coated with the above-mentioned releasable surface coating material, a permanent-bonding surface coating material having the following composition was added with a Mayer bar at a solid content of 10 g / solid.
m ^{2 was} coated and dried with a hot air dryer at a temperature of 100 ° C. for 1 minute to obtain a pressure-sensitive adhesive sheet (proprietary postcard paper for tri-fold postcard). "Coating composition for permanent adhesive surface" blending amount An acrylic adhesive obtained by copolymerizing 78% ethyl acrylate and 22% butyl acrylate in the presence of polyvinyl alcohol (Polysol OLZ-1103-7, manufactured by Showa High Polymer Co., Ltd., Nonionic adhesive, glass transition temperature −30 ° C.) 45 parts by mass, copolymer of diallylamine hydrochloride and acrylamide which is a resin containing a hydrochloride of a secondary amino group (Sumiraz resin 1001, manufactured by Sumitomo Chemical Co., Ltd.) 5 parts by mass, ethylene-vinyl acetate copolymer (Polysol OLY-3597, manufactured by Showa High Polymer Co., Ltd., nonionic binder) 20 parts by mass, wheat starch (AS-225, manufactured by Chiba Starch Co., non-gelatinized starch) 8 15 parts by weight of precipitated synthetic silica (Mizukasil P-526, manufactured by Mizusawa Chemical Industry Co., Ltd.), silanol group-modified polyvinyl acetate Call (PVA R-1130, manufactured by Kuraray Co., Ltd., a nonionic binder) 7 parts by mass, aids (dispersants, lubricants, defoamers, wetting agents) 4 parts by weight.

Example 2 A pressure-sensitive adhesive sheet (proprietary postcard for tri-fold postcard) was obtained in the same manner as in Example 1 except that the coating composition for the removable surface was changed to the following composition. "Removable surface coating composition" blending amount In the presence of a water-soluble cationic resin (copolymer of diallylamine hydrochloride and sulfone, PAS-92, manufactured by Nitto Boseki Co., 9 mass% of adhesive solids), acrylic Acrylic adhesive (Nicazole Y-9681, manufactured by Nippon Carbide Industry Co., Ltd., cationic adhesive, glass transition temperature -30 ° C) obtained by copolymerizing butyl acetate 76% and methyl methacrylate 24% 20 parts by mass, second grade Copolymer of diallylamine hydrochloride, which is a resin containing a hydrochloride of amino group, and acrylamide (Sumiraze resin 1001, Sumitomo Chemical Co., Ltd., a compound having a cation group) 10 parts by mass, ethylene-vinyl acetate copolymer ( Polysol OLY-3597, Showa Polymer Co., Ltd., nonionic binder) 20 parts by mass, wheat starch (AS-225, Chiba Starch Co., gelatinization) Unmodified starch) 5 parts by mass, precipitating synthetic silica (Mizukasil P-526, manufactured by Mizusawa Chemical Industry Co., Ltd.) 40 parts by mass, silanol group-modified polyvinyl alcohol (PVA R-1130, manufactured by Kuraray Co., Ltd., nonionic binder) 5 parts by mass. , Auxiliary agent (dispersant, lubricant, defoaming agent, wetting agent) 4 parts by mass.

Example 3 A pressure-sensitive adhesive sheet (proprietary postcard paper for tri-fold postcards) was obtained in the same manner as in Example 1 except that the paint for the removable surface was changed to the following composition. "Removable surface coating formulation" blending amount In the presence of a water-soluble cationic resin (copolymer of diallylamine hydrochloride and sulfone, PAS-92, manufactured by Nitto Boseki Co., Ltd., adhesive solid content 6.9% by mass). Acrylic adhesive obtained by copolymerizing 76% butyl acrylate and 24% methyl methacrylate (Nikasol Y-9682, manufactured by Nippon Carbide Industry Co., Ltd., cationic adhesive, glass transition temperature -30 ° C) 15 parts by mass, second grade Copolymer of diallylamine hydrochloride, which is a resin containing a hydrochloride of amino group, and sulfone (PAS-92, manufactured by Nitto Boseki Co., Ltd., a compound having a cation group) 8 parts by mass, ethylene-vinyl acetate copolymer (Polysol OLY -3597, Showa High Polymer Co., Ltd., nonionic binder) 20 parts by mass, wheat starch (AS-225, Chiba Starch Co., non-gelatinized starch) 5 parts by mass, Precipitable synthetic silica (Mizukasil P-526, manufactured by Mizusawa Chemical Co., Ltd.) 45 parts by mass, silanol group-modified polyvinyl alcohol (PVA R-2130, manufactured by Kuraray Co., Ltd., nonionic binder) 7 parts by mass, auxiliary agent (dispersant, lubricant) , Antifoaming agent, wetting agent) 4.5 parts by mass.

Example 4 A pressure-sensitive adhesive sheet (proprietary postcard for three-fold postcards) was obtained in the same manner as in Example 1 except that the paint for the removable surface was changed to the following composition. "Removable surface coating formulation" compounding amount An acrylic adhesive obtained by copolymerizing 98% of ethyl acrylate and 2% of an acrylic monomer having a hydroxyl group in the presence of polyvinyl alcohol (Polysol OLZ-11 39-2, Showa High Molecule company, nonionic adhesive, glass transition temperature -20 ° C) 18 parts by mass, copolymer of diallylamine hydrochloride and acrylamide which is a resin containing a hydrochloride of a secondary amino group (Sumirez Resin 1001, Sumitomo Chemical) Kogyo Co., Ltd., compound having cationic group) 9 parts by mass, styrene-butadiene copolymer (Nippol Lx-407K-3, manufactured by Nippon Zeon Co., amphoteric binder) 20 parts by mass, wheat starch (AS-225, Chiba Starch Co., Ltd.) 8 parts by mass of non-gelatinized starch), 40 parts of synthetic synthetic silica (Mizukasil P-526, manufactured by Mizusawa Chemical Industry Co., Ltd.) Parts, silanol-modified polyvinyl alcohol (PVA R-2130, manufactured by Kuraray Co., Ltd., a nonionic binder) 5 weight parts, aids (dispersants, lubricants, defoamers, wetting agents) 3 parts by weight.

Example 5 A pressure-sensitive adhesive sheet (proprietary postcard for tri-fold postcard) was obtained in the same manner as in Example 1 except that the paint for the removable surface was changed to the following composition. "Removable surface coating formulation" blending amount In the presence of a water-soluble cationic resin (copolymer of diallylamine hydrochloride and sulfone, PAS-92, manufactured by Nitto Boseki Co., Ltd., 2% by mass of solid adhesive) Acrylic adhesive obtained by copolymerizing 20% of butyl acidate, 78% of ethyl acrylate, and 2% of acrylic monomer having a hydroxyl group (Nikasol Y-9708, manufactured by Nippon Carbide Industry Co., Ltd., cationic adhesive, glass transition temperature -30) C) 15 parts by mass, a copolymer of diallylamine hydrochloride and sulfone, which is a resin containing a hydrochloride of a secondary amino group (PAS-92, manufactured by Nitto Boseki Co., Ltd., a compound having a cation group) 8 parts by mass, ethylene- 20 parts by mass of vinyl acetate copolymer (Polysol OLY-3597, Showa Polymer Co., Ltd., nonionic binder), wheat starch (AS-225, Chiba starch) 5 parts by mass of non-gelatinized starch), 45 parts by mass of precipitating synthetic silica (Mizukasil P-526, manufactured by Mizusawa Chemical Co., Ltd.), silanol group-modified polyvinyl alcohol (PVA R-2130, manufactured by Kuraray Co., Ltd., nonionic binder) ) 7 parts by mass, auxiliary agent (dispersant, lubricant, defoaming agent, wetting agent) 4.5 parts by mass.

Example 6 In the same manner as in Example 1 except that the removable coating material prepared in Example 1 was used to coat both surfaces of a high-quality paper, a pressure-sensitive adhesive sheet (trifold postcard confidential I got a postcard).

Comparative Example 1 A pressure-sensitive adhesive sheet (proprietary postcard for three-fold postcards) was obtained in the same manner as in Example 1 except that the paint for the removable surface was changed to the following composition. "Removable surface coating compounding amount " 35 parts by mass of methyl methacrylate-modified natural rubber latex (Flutite FB-DO-3, Mitsui & Co. Solvent Coating Co., anionic adhesive), styrene-butadiene copolymer (Polylac) 750K-101, manufactured by Mitsui Chemicals, Inc., anionic binder 20 parts by mass, wheat starch (AS-225, manufactured by Chiba Starch Co., non-gelatinized starch) 10 parts by mass, precipitating synthetic silica (Mizukasil P-526, Mizusawa) Chemical Industry Co., Ltd.) 29 parts by mass, Polyvinyl alcohol (PVA-105, Kuraray Co., Ltd., nonionic binder) 5 parts by mass, Auxiliary agent (dispersant, lubricant, defoaming agent) 1 part by mass.

Comparative Example 2 A pressure-sensitive adhesive sheet (proprietary postcard for three-fold postcards) was obtained in the same manner as in Example 1 except that the paint for the removable surface was changed to the following composition. "Removable surface coating compounding" compounding amount Acrylic ester copolymer (AE-923, manufactured by Japan Synthetic Rubber Co., Ltd., anionic adhesive) 60 parts by mass, wheat starch (AS-225, manufactured by Chiba Starch Co., gelatinized) 50 parts by mass, synthetic amorphous silica (Fanseal X37B, manufactured by Tokuyama Soda Co., Ltd.) 50 parts by mass, styrene-triethylammonium acrylate chloride copolymer (cationic compound having quaternary ammonium group) 40 parts by mass Department.

Comparative Example 3 A pressure-sensitive adhesive sheet (proprietary postcard for tri-fold postcard) was obtained in the same manner as in Example 1 except that the paint for the removable surface was changed to the following composition. "Removable surface coating compounding amount " 60 parts by mass of methyl methacrylate modified natural rubber latex (Flutite FB-DO-3, anionic adhesive manufactured by Mitsui & Co. Solvent Coating Co., Ltd.), calcium carbonate (Softon 1000, Bihoku powder) Chemical Industry Co., Ltd.) 50 parts by mass, synthetic amorphous silica (Fanseal X37B, manufactured by Tokuyama Soda Co., Ltd.) 50 parts by mass, styrene-ethyl acrylate diethyldiethylamine copolymer (cationic compound having tertiary amino group) 40 parts by mass Department.

Comparative Example 4 A acrylamide / diallylamine copolymer as a cation resin was dried on a support having a basis weight of 115 g / m ² made with a Fourdrinier paper machine to have a deposition amount of 0.8 g / m ² , and a phosphoric acid esterified starch was dried. The on-machine size press machine was used to adhere to the front and back sides so that the adhered amount was 1.2 g / m ^2, and machine calendering was performed to prepare a support. A pressure-sensitive adhesive having the following composition was applied to one surface of the support using an air knife coater at a rate of 10 g / m ² and dried to obtain a pressure-sensitive adhesive sheet. "Removable surface coating compounding" compounding amount Acrylic ester copolymer (AE-923, manufactured by Japan Synthetic Rubber Co., Ltd., anionic adhesive) 60 parts by mass, wheat starch (AS-225, manufactured by Chiba Starch Co., gelatinized) Not starch) 40 parts by mass, synthetic silica (Mizukasil P-832, manufactured by Mizusawa Chemical Industry Co., Ltd.) 50 parts by mass.

"Evaluation Method" (1) Adhesiveness of Adhesive Layer with Base Sheet (Support) The adhesive layer was rubbed with a finger and the adhesiveness with the base sheet was visually evaluated. A: The adhesive layer is not peeled off at all. ◯: Adhesive layer peels off only partly, but is almost good. Δ: The adhesive layer is slightly peeled off, but it is at a level where there is no practical problem. X: The adhesive layer is peeled off, which is a practical problem.

(2) Evaluation of water resistance of printing : Yellow, magenta, cyan, and black were printed on the re-peeling surface using an ink jet printer MC-830 (manufactured by Seiko Epson Corporation), and the ink when immersed in water for 2 minutes Bleeding was visually evaluated. ⊚: Excellent without bleeding. ○: Almost no bleeding. Δ: Some bleeding is recognized, but there is no problem in practical use. X: There is bleeding and there is a practical problem. XX: Marked bleeding

(3) Evaluation of Print Density Black was printed on the re-peeling surface using an ink jet printer MC-830 (manufactured by Seiko Epson Corporation) and evaluated by a Macbeth densitometer (RD-914).

(4) Evaluation of contact angle The contact angle with respect to water was 20 ° C. in accordance with ASTM D5725, and water (4 μl) was applied to the adhesive layer under an atmosphere of 65% RH.
Was measured 10 seconds after the dropping. The contact angle measuring device is FIB
RO system ab dynamic contact angle absorption tester FIBRO DAT
1100 was used.

(5) Stability evaluation of paints Adhesives, pigments, cationic compounds, auxiliaries and the like are mixed and stirred to adjust the paints to be used in the present invention. I observed. ◯: No change and stable. Δ: The viscosity slightly increases, but there is no problem. X: Viscosity increases sharply, or agglomerates are generated, resulting in instability.

(6) Adhesiveness / Removability of Removable Surface Using a dry sealer (manufactured by Toppan Forms Co., Ltd.), the obtained three-fold postcard sample was cut into an appropriate size, and the removable surfaces faced each other. Z-fold as you do, 23 ℃, 65
After adjusting the humidity for 24 hours under the temperature and humidity conditions of 1%, set the roll gap to 1
Press through a press roll set to 50 μm and crimp,
I created a confidential postcard. The obtained confidential postcard was re-peeled by T-type peeling, and the state of peeling and the state of the peeled surface were evaluated. ◯: Re-peeled. Good. Δ: Re-peeled but weak in adhesive force, or part (fine)
Although the base material will be destroyed, there is no practical problem. X: A level at which practically a problem occurs, in which the substrate is broken or the adhesive force is low and the substrate is easily peeled off.

(7) Inkjet Suitability Evaluation Yellow, magenta, cyan, and black were halftone dot printed using an inkjet printer MC-830 (manufactured by Seiko Epson Corp.), and the shape of dots was observed with a stereoscopic microscope to see ink bleeding. It was evaluated by. ◯: There is no problem in the dot shape and there is no problem. Δ: The shape of the dots is slightly broken, but there is no problem in practical use. X: The dot is largely broken, which is a problem in practical use.

(8) Comprehensive Evaluation Comprehensive evaluation as a confidential postcard paper was performed. ⊚: Excellent as a private postcard. ○: Excellent as a confidential postcard. Δ: There are some problems as confidential postcards, but there is no problem in practical use. ×: There is a problem as a confidential postcard, and it is a level that cannot be put to practical use.

[0071]

[Table 2]

[0072]

INDUSTRIAL APPLICABILITY In a pressure-sensitive adhesive sheet having a substrate sheet and an adhesive layer on at least one surface according to the present invention, the adhesive layer contains two or more different acrylic monomers in the presence of a water-soluble polymer. By providing a coating layer containing a polymerized acrylic adhesive, a cationic compound (a compound having a cation group and / or a functional group capable of becoming a cation group), and an adhesive force control agent, suitability for an inkjet printer, particularly printing density It is possible to obtain a pressure-sensitive adhesive sheet which is high in water resistance, excellent in water resistance of printing, and which has satisfactory adhesion and removability when used as a postcard. Further, since the adhesive exhibits nonionic or cationic properties, the coating composition containing various cationic compounds is excellent in stability, and the obtained pressure-sensitive adhesive sheet has excellent light resistance and water resistance.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09J 133/06 C09J 133/06 133/14 133/14 133/26 133/26 139/02 139/02 157 / 06 157/06 201/00 201/00 F term (reference) 2C005 WA02 WA15 2H086 BA01 BA15 BA35 BA36 BA41 4J004 AA08 AA10 FA10 4J040 DD021 DF041 DF051 DF092 DH012 GA14 GA15 GA16 JA09 PA23

Claims (8)

[Claims] 1. A base material sheet having an adhesive layer on at least one surface thereof, which can be adhered by subjecting the adhesive layers to a strong pressure treatment in a state where the adhesive layers are opposed to each other. In a pressure-sensitive adhesive sheet which is peelable, the adhesive layer contains an adhesive, a cation group and / or an adhesive containing an acrylic resin obtained by copolymerizing two or more different acrylic monomers in the presence of a water-soluble polymer. Alternatively, a pressure-sensitive adhesive sheet comprising a compound having a functional group capable of forming a cationic group and an adhesive force control agent. 2. The pressure-sensitive adhesive sheet according to claim 1, wherein the water-soluble polymer is polyvinyl alcohol. 3. The pressure-sensitive adhesive sheet according to claim 1, wherein the water-soluble polymer is a resin having a cationic group and / or a functional group capable of becoming a cationic group. 4. The pressure-sensitive adhesive sheet according to claim 3, wherein the resin having a cationic group and / or a functional group capable of forming a cationic group is a copolymer of diallylamine hydrochloride and sulfone. 5. The pressure-sensitive adhesive sheet according to claim 1, wherein the water-soluble polymer is poly (2-hydroxyethyl methacrylate). 6. The pressure-sensitive adhesive sheet according to claim 1, wherein the contact angle of the surface of the adhesive layer 10 seconds after dropping water is 100 ° or less. 7. The compound having a cation group and / or a functional group capable of forming a cation group is at least one selected from compounds having a primary amino group or an addition salt thereof and a secondary amino group or an addition salt thereof. The pressure-sensitive adhesive sheet according to any one of claims 1 to 6. 8. The method according to claim 7, wherein the compound having a cation group having a secondary amino group or an addition salt thereof and / or a functional group capable of becoming a cation group is a copolymer of diallylamine and acrylamide or an addition salt thereof. Pressure sensitive adhesive sheet.