JP2002206077A - 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 the water resistance of the printed letters, and satisfies adhesivity and removability as paper for confidential postcards. SOLUTION: This pressure-sensitive adhesive sheet having an adhesive layer containing an adhesive and an adhesive force-controlling agent on at least one side of a substrate sheet, wherein the adhesive layer can be adhered by subjecting the adhesive layers to a strong pressure treatment in a mutually faced state and the adhesive sides can be peeled, is characterized in that the adhesive layer contains a cationic compound having at least one selected from a primary amino group or its adduct salt and a secondary amino group or its adduct salt.

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 for various systems such as postcards and cards having confidentiality.

[0002]

2. Description of the Related Art In recent years, in accordance with the revision of the Postal Code, a sheet on which necessary information is recorded is folded in two or three.
Postcard systems with confidentiality have been commercialized and spread.
Postcards having such confidentiality usually have no adhesiveness on one side of the base sheet, exhibit adhesiveness by pressing the adhesive layers in a state where they face each other, and re-peel after adhesion. A pressure-sensitive adhesive sheet (hereinafter also referred to as confidential postcard) having an adhesive layer capable of being used is used.

Normally, a pressure-sensitive adhesive sheet prints fixed-form items as postcards, then prints information such as personal information that is to be kept secret on the adhesive layer surface, and addresses and other information on other portions using a printer or the like, and then uses a dry sealer or the like. The confidential information is layered under pressure so that it cannot be seen from the outside to form a confidential postcard. The confidential postcard is a postcard from which the recipient can obtain information by peeling off from the adhesive layer, and once peeled off, the adhesive surface has no adhesiveness and thus does not come to the state before peeling.

[0004] Initially, postcard systems that maintain confidentiality were printed on confidential postcards by relatively large-scale printing companies and the like.
It was printed with a high-speed laser printer, crimped with a dry sealer, and shipped. In recent years, the printing method has been changing from a high-speed laser printer method to a high-speed ink jet printer method provided with drying equipment capable of processing a large amount.

[0005] In the ink jet system, ink droplets are made to fly by various recording systems and adhere to a recording sheet such as paper to record images, characters, and the like. Normally, the recording sheet has a high density of print dots, a bright and vivid color tone, no color sinking, and the ink absorbs quickly, causing ink to flow or bleed even when print dots overlap. However, it is required that the diffusion in the lateral direction be small.

[0006] Since a high-speed ink jet printer uses an anionic dye ink, printing on ordinary confidential postcard paper does not have water resistance of the ink and runs off due to water. Therefore, in order to make the confidential postcard into an inkjet-compatible paper, an undercoat layer of a cationic compound is provided between the base sheet and the adhesive layer, or the adhesive layer contains cationic colloidal silica or a cationic compound. However, it has been difficult to impart inkjet recording suitability while maintaining the function of the adhesive layer.

[0007] The above problem was thought to have been solved by changing the recording ink to a water-resistant pigment-based ink. However, the pigment-based ink had poor fluidity when printing at high speed, and the dye-based ink was poor. However, there is a problem that nozzle clogging frequently occurs because the drying is relatively easy. As a countermeasure, printing is performed at a line speed of about 1/3 to 1/4 compared with that of the dye system, and at present, the performance of the high-speed ink jet printer is not sufficiently exhibited.

Japanese Patent Application Laid-Open No. 09-39378 discloses that a quaternary ammonium group or a tertiary ammonium group is added to the pressure-sensitive adhesive layer.
Although a method of adding a cationic compound having a secondary amino group has been reported, the pressure-sensitive adhesive contained in the adhesive becomes unstable depending on the cationic component to be added, and a sufficient adhesive force at the time of pressurization, Or, disadvantages such as removability cannot be obtained.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet printer which is excellent in suitability, in particular, less bleeding of printing, excellent in water resistance of printing, and satisfies adhesiveness and removability as confidential postcard paper. It is to provide a pressure-sensitive adhesive sheet at low cost.

[0010]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a primary amino group or an addition salt thereof, or a secondary amino group or By adding a cationic compound having a salt, a pressure-sensitive adhesive sheet having both ink jet suitability and print water resistance was obtained. In addition, the present inventors have found that when an anionic component (for example, an anionic SBR latex) is removed from the components of the adhesive layer in order to further enhance the inkjet suitability, the adhesion between the base sheet and the adhesive layer is poor. It has been found that there is a problem that the adhesion can be greatly improved by blending an amphoteric resin having both cationic and anionic functional groups in one molecule in the adhesive layer. Invented the invention.

The present invention includes the following embodiments. [1] At least one surface of a base sheet has an adhesive layer containing an adhesive and an adhesive force control agent, and the adhesive layer is subjected to high pressure treatment with the adhesive layers facing each other. Wherein the adhesive layer is at least one cation selected from a primary amino group or an addition salt thereof and a secondary amino group or an addition salt thereof. A pressure-sensitive adhesive sheet comprising a hydrophilic compound. [2] The cationic compound is 1% of the solid content weight of the adhesive layer.
The pressure-sensitive adhesive sheet according to [1], which contains about 70% by weight.

[3] The feeling described in any one of [1] and [2], wherein the adhesive layer further contains an amphoteric resin having both cationic and anionic functional groups in one molecule. Pressure bonding sheet. It is more preferable because the adhesiveness between the adhesive layer and the substrate is excellent. [4] The pressure-sensitive adhesive sheet according to any one of [1] to [3], wherein the adhesive layer further contains a hydrophilic polymer. It is preferable because the adhesiveness between the adhesive layer and the substrate and the miscibility with the cationic compound are excellent. [5] The pressure-sensitive adhesive sheet according to any one of [1] to [4], wherein the cationic compound has a secondary amino group or an addition salt thereof. [6] The pressure-sensitive adhesive sheet according to item 5, wherein the cationic compound having a secondary amino group or an addition salt thereof is a copolymer of diallylamine and (meth) acrylamide or an addition salt thereof. In the present invention, the cationic compound refers to an organic substance containing from low molecular weight to high molecular weight. In the present invention, the adhesive is a polymer having an adhesive property.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The pressure-sensitive adhesive sheet used in the present invention is characterized in that the adhesive layer provided on at least one surface of the substrate sheet does not show adhesiveness in a normal state before pressing, and 500 kg / c with the agent layers facing each other
It can be bonded by applying a pressure treatment to about m ² , and the bonding surface has a removable adhesive layer. That is, a configuration in which an adhesive layer surface having removability (hereinafter, referred to as a “removable surface”) is formed only on one surface of a base sheet, and an adhesive layer having removability on both surfaces of a base sheet (removable surface) Surface), a structure in which a removable adhesive layer (removable surface) is provided on one side of the base sheet, and a non-removable surface (hereinafter referred to as a permanent adhesive surface) is provided on the other surface. Etc. are included.

The re-peelable surface and the permanent adhesive surface do not show adhesiveness in a normal state, and are adhered by laminating under pressure with a dry sealer or the like. The adhesive force is adjusted by adjusting the amount of the force control agent. For example, after providing information that requires confidentiality on the removable surface, fold the sheet so that the information is hidden,
Alternatively, another sheet is overlaid and subjected to a pressure treatment so that the removable adhesive layers face each other, thereby forming a laminated sheet (for example, a postcard, a lottery, etc.) having information inside.

The present invention comprises an adhesive and an adhesive strength control agent, wherein at least one selected from a cationic compound having a primary amino group or an addition salt thereof and a secondary amino group or an addition salt thereof in the adhesive layer. There is a great feature in that one kind of cationic compound is contained.

Examples of the cationic compound having a primary amino group or an addition salt thereof used in the present invention include monoallylamine, monoallylamine addition salt, primary amines of alkyl (meth) acrylate, and alkyl (meth) acrylate. Primary amine addition salts of esters, derivatives containing primary amino groups derived from these compounds, and oligomers and polymers containing these are also included.
The above-mentioned addition salts include hydrochloride, hydrobromide, hydroiodide, sulfonate, and p-toluenesulfonate. Examples of the cationic compound having a secondary amino group or an addition salt thereof used in the present invention include diallylamine, diallylamine addition salt, secondary amines of alkyl (meth) acrylate, and secondary amine of alkyl (meth) acrylate. Addition salts, derivatives containing a secondary amino group derived from these compounds, oligomers and polymers containing these, and the like are included. Particularly, a copolymer of diallylamine and (meth) acrylate is preferred. In addition, as the above-mentioned addition salt, hydrochloride,
Examples include hydrobromide, hydroiodide, sulfonate, and p-toluenesulfonate.

A primary amino group or an addition salt thereof and 2
When at least one cationic compound selected from a secondary amino group or an addition salt thereof is used as a polymer, the proportion of the cationic compound in all monomers used is 1 to 70 mol%, preferably 2 to 50 mol. %. The polymerization reaction is carried out by continuously adding another copolymerizable monomer to the aqueous solution containing the cationic compound. The addition rate may be constant or non-constant, and the addition time is usually in the range of 1 to 10 hours. In the polymerization reaction, the concentration is preferably from 1 to 80% by weight, more preferably from 5 to 50% by weight.

In the polymerization, it is preferable to use a polymerization initiator such as persulfates such as ammonium persulfate and potassium persulfate, 2,2'-diamidino-2,2'-azopropane dihydrochloride, azobis Examples include azo compounds such as isobutyronitrile, and peroxides such as di-t-butyl peroxide, cumene hydroperoxide and hydrogen peroxide. In addition, a known redox initiator such as a combination of potassium persulfate and sodium hydrogen sulfite or a tertiary amine can be used. The polymerization initiator may be previously added to the aqueous solution containing the cationic compound, or may be continuously added to the system simultaneously with the other copolymerizable monomers.

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

The amount of hypophosphorous acid or a salt thereof used is 0.01 to 3 based on the total number of moles of the monomers used.
Mol% is preferable, and more preferably 0.02 to 2 mol%.
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 the system may be continuously added simultaneously with other copolymerizable monomers. It may be added inside.

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 an ammonium salt thereof may be used as necessary. it can.
In other words, when metal ions, particularly transition metal ions, coexist or mix in the polymerization system, these ions cause an undesirable decrease in viscosity of the resulting water-soluble copolymer, and therefore the purpose of removing such inhibitors It is also effective to add a chelating agent to the polymerization system.

When a chelating agent is used, its use amount is not particularly limited. However, in order to exert its effect effectively, 50 ppm based on the total monomer weight used is used.
It is preferable to use the above. The upper limit of the amount of the chelating agent is arbitrary and can be used in a considerable amount as long as no adverse effects are produced. However, considering economic efficiency and the like, it is sufficient that the amount is up to about 5000 ppm based on the weight of all monomers used.

When a chelating agent is used, it may be added to an aqueous solution containing a cationic compound in advance similarly to a polymerization initiator or hypophosphorous acid or a salt thereof, or may be mixed with another copolymerizable monomer. At the same time, they 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.
It is in the form of an aqueous emulsion. Aqueous emulsions of cationic compounds can be obtained by emulsion polymerization.
In emulsion polymerization, an emulsifier is usually used to impart polymerization stability. However, since the emulsifier causes a decrease in adhesive strength, it is preferable to use a minimum necessary amount. In addition, an aqueous emulsion of a cationic copolymer can be produced by a method without using an emulsifier so as not to lower the adhesive strength. As such a method, for example, after polymerizing a monomer in an organic solvent, water is added in a necessary amount, and then the organic solvent used for the polymerization is removed by, for example, distillation under reduced pressure or the like, to obtain an aqueous emulsion. Law.
Further, at least one cationic functional group selected from a primary amino group or an addition salt thereof and a secondary amino group or an addition salt thereof may be introduced into the adhesive by the above method.

The amount of at least one cationic compound selected from the primary amino group or its addition salt and the secondary amino group or its addition salt used in the present invention is as follows:
The content is preferably 1 to 70% by weight based on the solid content of the adhesive layer, and 5 to 5%.
0% by weight is preferred. By the way, if the blending amount is less than 1% by weight, the adhesive strength becomes too strong, and after ink jet printing, press-fitting and re-peeling, the print is transferred to the non-printing surface, and the water resistance and ink absorption are sufficient. On the other hand, if the compounding amount exceeds 70% by weight, the adhesiveness at the time of pressure treatment is reduced, the function as a pressure-sensitive adhesive sheet is impaired, and the adhesion of the print and the water resistance of the print tend to be inferior. .

The adhesive used in the present invention includes synthetic rubbers such as natural rubber, modified natural rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, ethylene-vinyl acetate copolymer resin, acrylate resin, and vinyl chloride resin. Resin and vinylidene chloride resin can be exemplified. In particular, from the viewpoint of suitability for ink jet recording, an adhesive that does not cause aggregation when a cationic resin is added, that is, an adhesive that does not exhibit anionic property or a cationic adhesive is preferable.

Examples of the adhesive having no anionic property include, for example, an adhesive which is polymerized using a nonionic surfactant when grafting an acrylic monomer such as methyl methacrylate onto natural rubber, or a copolymer of an acrylic monomer. For example, an adhesive that is polymerized by using a nonionic surfactant at the time of the bonding may be used.

As the cationic adhesive, for example, when grafting an acrylic monomer such as methyl methacrylate onto natural rubber, a monomer having a primary amino group or an addition salt thereof, or a secondary amino group or an addition salt thereof may be used. At least one cationic monomer selected from a primary amino group or an addition salt thereof and a secondary amino group or an addition salt thereof when polymerizing a cationized product, a styrene-butadiene rubber or an acrylic resin; It is preferable to use an adhesive or the like that has been cationized by copolymerization with a simple substance or in combination with another resin. Specifically, at least one cationic monomer selected from a primary amino group or an addition salt thereof and a secondary amino group or an addition salt thereof is cationized by copolymerization with another monomer. Among them, at least one selected from a cationic compound having a primary amino group or an addition salt thereof and a secondary amino group or an addition salt thereof.
Those obtained by copolymerizing a kind of cationic compound with another copolymerizable acrylic monomer are preferable from the viewpoints of water resistance, heat resistance and friction resistance of printing. The glass transition temperature of the adhesive is preferably about -40C to -10C.

Examples of the cationic compound (monomer) used for polymerizing the cationic adhesive include:
Monoallylamine, monoallylamine addition salt, (meth)
Primary amines of acrylic acid alkyl esters, (meth)
Primary amine addition salts of alkyl acrylates, diallylamine, diallylamine addition salts, secondary amines of alkyl (meth) acrylates, secondary amine addition salts of alkyl (meth) acrylates and the like are preferably used. The above-mentioned addition salts include hydrochloride, hydrobromide, hydroiodide, sulfonate, and p-toluenesulfonate. When at least one cationic compound selected from a primary amino group or an addition salt thereof and a secondary amino group or an addition salt thereof is used as an adhesive, the proportion of the cationic monomer in the total monomers used is 1%. ~ 70 mol%, preferably 2
~ 50 mol%. Other monomers constituting the adhesive include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth)
Isopropyl acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, (meth) acrylic acid -2-ethylhexyl, lauryl (meth) acrylate, (meth)
Stearyl acrylate, 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, α-ethyl (meth) acrylamide, N-methyl (meth) acrylamide, N-butoxymethyl (meth)
Acrylamide, diacetone (meth) acrylamide,
(Meth) acrylic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (meth) acrylic acid- 3-hydroxypropyl, 4-hydroxybutyl (meth) acrylate, vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, diethylene glycol (meth) acrylate, triethylene glycol (meth) acrylate, polyethylene (meth) acrylate Glycol and the like. The proportion of other monomers in the total monomers used is 30 to 99 mol%, preferably 35 to 75 mol%.
Mol%.

The amount of the adhesive in the adhesive layer on the removable surface is
Solids weight is 15-50% by weight. When the amount is less than 15% by weight, the adhesive strength of the adhesive layer becomes too weak, and when the amount exceeds 50% by weight, the pigment on the surface of the adhesive layer is covered, so that the ink absorbability is reduced and the suitability for inkjet is reduced.
On the other hand, the permanent adhesive layer contains an adhesive and a pigment. The amount of the adhesive in the permanent adhesive layer is 30 to 70 in terms of solid weight.
% By weight. By the way, if the amount is less than 30% by weight, removability is exhibited, and if it exceeds 70% by weight, blocking tends to occur.

As the adhesion control agent, inorganic and organic pigments can be used. For example, zinc oxide, titanium oxide, zeolite, calcium carbonate, clay, aluminum oxide, wheat starch, silica, alumina, γ-alumina,
Colloidal silica, plastic pigment, polyethylene resin, polypropylene resin, fluorine resin and the like can be mentioned. Among them, wheat starch, silica and the like are suitable for controlling the adhesive force and are preferably used.

Also, wheat starch is used as a spacer for the purpose of preventing blocking. Silica is preferable because it has excellent ink receptivity and improves printability and inkjet recording suitability. Fluorine-based resins are highly effective in preventing ink bleeding. Further, titanium oxide has a high hiding effect, and the hiding effect is enhanced by mixing with silica.
It is preferable that such an inorganic or organic pigment is used in combination as the adhesion control agent. The inorganic or organic pigment has a particle size of about 1 to 50 μm. The adhesive force control agent is adjusted so that the coated surface adheres under pressure and does not adhere once peeled off.

When an anionic component is removed from the adhesive composition in order to enhance the suitability for ink jet, the adhesion between the base material sheet and the adhesive layer is deteriorated.
Adhesion can be dramatically improved by blending an amphoteric resin having a cationic functional group and an anionic functional group in the molecule. This is presumably because the amphoteric resin has good miscibility with various pigments and exhibits strong adhesion to the pigment, so that the adhesiveness of the formed adhesive layer can be improved. The amphoteric resin has both a cationic functional group and an anionic functional group in one molecule. The amphoteric resin is described, for example, in JP-A-54-30910 (a composition for paper coating, particularly a composition having improved ink transferability in multicolor printing in offset printing. Amino in one molecule) A latex containing both a group and a carboxylic acid is described) and JP-A-63-90521 (which provides a method for producing amphoteric polymer particles having a low impurity content).
Ethylenically unsaturated amine monomer in lower alcohol,
A method for radically polymerizing an ethylenically unsaturated carboxylic acid monomer and a nonionic ethylenically unsaturated amide monomer is described), and JP-A-10-279639 (which exhibits good opacity and whiteness, and has good water absorption and ink properties). The present invention provides amphoteric hollow polymer particles which are excellent in printability such as transferability, have good polymerization stability at the time of production, are uniform in quality, and are useful as a paper coating composition. Having a multilayer structure consisting of at least three layers of a core polymer comprising a copolymer, an intermediate layer polymer surrounding the core polymer, and an outer layer polymer surrounding the intermediate layer polymer, and
An amphoteric hollow polymer particle having a void formed by a neutralization reaction of an acidic group in a core polymer, and further having a reactive group exhibiting cationicity in a pH range of 3 to 8 introduced after polymerization is described. JP-A-10-36471 (Providing a production method capable of obtaining an amphoteric polyurethane aqueous dispersion by a simple process. A polyol compound, a polyisocyanate compound, and having at least two active hydrogens and a carboxyl group. The compound is reacted with an isocyanate group excess to form an isocyanate group-containing prepolymer, then reacted with two or more active hydrogens and a compound having a tertiary amino group, and then dispersed in water. And a compound having a tertiary amino group in which the same effect can be obtained even if the order is changed. It may be prepared by methods described in equal.

Further, when an amphoteric resin is contained in the coating solution for the adhesive layer, the effect as a surfactant is small, the foaming property is relatively low, the stability is stable in a wide pH range, and the compatibility with the cationic polymer is also improved. Preparation of the coating liquid is easy, for example, the solvent shock does not often occur.

The amount of the amphoteric resin used in the present invention is 1 to 40% by weight based on the solid content of the adhesive layer.
~ 30% by weight is preferred. By the way, 1% by weight
If it is less than 1, the water resistance and ink absorption are not sufficient, and the adhesion between the support and the adhesive layer is insufficient, causing problems such as powder dropping. If the amount is more than 40% by weight, the adhesiveness during the pressure treatment is reduced, the function as a pressure-sensitive adhesive sheet is impaired, and the water resistance of printing tends to be poor.

In the case of a postcard that is folded in three folds (hereinafter also referred to as a tri-fold postcard), the adhesive layer on the permanent bonding surface may also form the postcard surface. Containing a compound having an amphoteric functional group,
It is preferable to provide inkjet recording suitability.

Further, carboxymethylcellulose, casein, dextrin, starch, modified starch,
When a hydrophilic polymer such as polyvinyl alcohol, modified polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, polyvinyl methyl ether, polyacrylic acid, polyacrylamide, alkyl acrylate copolymer and urethane copolymer is blended, an adhesive layer is formed. This is preferred because the adhesion between the polymer and the base material and the miscibility with the cationic compound are improved. When a hydrophilic polymer is blended, the content is preferably 10% by weight or less based on the solid content of the adhesive layer. 1
If the amount exceeds 0% by weight, the viscosity of the coating solution will increase and the adhesiveness will decrease. In the adhesive layer, a pigment dispersant, a thickener, a fluidity improver as an additive,
Antifoaming agent, foam inhibitor, release agent, foaming agent, penetrant, coloring dye,
UV absorbers, antistatic agents, cationic, nonionic or amphoteric surfactants, antioxidants, preservatives, waterproofing agents, JP-A-5-295335 (adhesion, removability, blocking resistance, Printability, water-based ink acceptability,
Provided is a cold seal adhesive composition having characteristics such as surface texture. An adhesive base comprising a mixture of a rubber latex and a protective colloid-based acrylic copolymer emulsion, or an adhesive base comprising an acrylic-modified rubber latex, and a filler;
A cold seal adhesive composition containing 5 to 90 parts by weight of the above filler with respect to 0 parts by weight. The reason for using the protective colloid adhesive is that the composition obtained by introducing a hydrophilic group by the protective colloid improves the anchoring property to the paper surface, and the glass transition temperature of the protective colloid is high, so the surface hardness is hard and the blocking resistance is high. Improve
The surface of the coating film does not form a film due to poor film formation during drying, and ink acceptability and printability are improved.The above protective colloid-based acrylic copolymer emulsion has its minimum by adjusting the monomer composition. Film forming temperature 9
It is described that it is preferable to set the temperature at 0 ° C. or higher).

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

Further, in the winding up after the adhesive layer coating, the method of Japan TAPPI paper pulp test method N
o. Standard deviation of winding hardness specified in 37-81 method is 5K
gf · m or less is preferable. When the maximum value of the standard deviation of the winding hardness exceeds 5 kgf · m, when the adhesive layer is applied, unnecessary deformation of the paper occurs, and the dimensions of the paper are different between the left and right sides. High-speed printing using a form printing machine may cause troubles such as wrinkles and misregistration.

In the case of coating on the surface, the coating method is not particularly limited, but various blade coaters, roll coaters, air knife coaters, bar coaters,
A gravure coater, a die coater, a curtain coater and the like are used. Among them, air knife coater,
Bar coaters and gravure coaters are preferred. The coating amount is in the range of ^{2 to} 30 g / m ² , preferably in the range of ^{3 to} 15 g / m ² .

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples. “Parts” and “%” shown in Examples are parts by weight and% by weight unless otherwise specified.

[0041]

Example 1 [Formation of Removable Adhesive Layer] 81.3 g / m of high quality paper
² (OKH70, manufactured by Oji Paper Co., Ltd.) 10 g of a paint for re-peeling surface of the following composition was applied to one side of
/ M ² and dried at a temperature of 100 ° C. for 1 minute in a hot air drier. Amount of “coating composition for removable surface” Acrylic adhesive polymerized using nonionic surfactant (Licabond AP-P 0022-5, manufactured by Chuo Rika Kogyo Co., Ltd.) 40 parts by weight Hydrochloride of secondary amino group Copolymer of diallylamine hydrochloride and acrylamide as resin to be contained (Sumireze Resin 1001, manufactured by Sumitomo Chemical Co., Ltd.) 4 parts by weight SBR amphoteric ion latex (Acostar C177, manufactured by Mitsui Cytec) 20 parts by weight Wheat starch ( AS-225, manufactured by Chiba Starch Co., Ltd.) 10 parts by weight Precipitable synthetic silica (Mizukasil P-527, manufactured by Mizusawa Chemical Industries) 25 parts by weight Auxiliary agent (dispersant, lubricant, defoamer, wetting agent) 1 part by weight

[Formation of Permanent Adhesive Adhesive Layer] On the opposite side of the high-quality paper coated with the above-described re-peelable surface paint, a permanent adhesive surface paint having the following composition was applied using a Meyer bar at a rate of 10 g / solid.
m ^{2 was} applied and dried for 1 minute at a temperature of 100 ° C. with a hot air drier to obtain a pressure-sensitive adhesive sheet (confidential postcard for tri-fold postcard). "Permanent adhesive surface for paint formulations" amount nonionic surfactant polymerized acrylic adhesive using the hydrochloride salt of (Rikabondo AP-P 0022-5, central Rika Co., Ltd.) 65 parts by weight of secondary amino groups 5 parts by weight of a copolymer of diallylamine hydrochloride and acrylamide as a resin contained (Sumireze Resin 1001, manufactured by Sumitomo Chemical Co., Ltd.) 3 parts by weight of SBR amphoteric ion latex (Acostar C177, manufactured by Mitsui Cytec) 3 parts by weight Wheat starch ( AS-225, manufactured by Chiba Starch Co., Ltd.) 11 parts by weight Precipitable synthetic silica (Mizukasil P-527, manufactured by Mizusawa Chemical Industry Co., Ltd.) 15 parts by weight Auxiliary agent (dispersant, lubricant, defoamer, wetting agent) 1 part by weight

Example 2 Except that the cationic compound was replaced with a polyallylamine hydrochloride (PAA-HCl-10L, manufactured by Nitto Boseki Co., Ltd.) which is a resin containing a hydrochloride of a primary amino group in the paint composition for a removable surface. In the same manner as in Example 1, a pressure-sensitive adhesive sheet (confidential postcard for tri-fold postcard) was obtained.

Example 3 A pressure-sensitive adhesive sheet (a confidential postcard for tri-fold postcard) was obtained in the same manner as in Example 1 except that the paint for the re-peelable surface was prepared as follows. 25 % by weight of cation-modified natural rubber-based latex (Frutite FB-3001, manufactured by Mitsui & Co., Ltd. Solvent Coating Co., Ltd.) diallylamine hydrochloride which is a resin containing a hydrochloride of a secondary amino group 18 weight parts SBR zwitterionic latex (Nippol Lx-407K-3, manufactured by Zeon Corporation) 16 weight parts Wheat starch (AS-225) , Manufactured by Chiba Starch Co., Ltd.) 10 parts by weight Precipitable synthetic silica (Mizukasil P-527, manufactured by Mizusawa Chemical Industry Co., Ltd.) 29 parts by weight Resin having a minimum film forming temperature of 90 ° C. or more, protective colloid-based acrylic copolymer emulsion (GV-008B) 1 part by weight Auxiliary agent (dispersant, lubricant, defoamer, wetting agent) 1 part by weight

Example 4 A pressure-sensitive adhesive sheet (a confidential postcard for tri-fold postcards) was obtained in the same manner as in Example 1 except that the paint for the re-peelable surface had the following composition. "Coating composition for removable surface" Compounding amount Cation-modified natural rubber-based latex (Furtite FB-3001, manufactured by Mitsui & Co., Ltd. Solvent Coating Co., Ltd.) 40 parts by weight Diallylamine hydrochloride which is a resin containing a hydrochloride salt of secondary amino group 5 parts by weight of a copolymer of acrylamide and acrylic amide (Sumilez Resin 1001, manufactured by Sumitomo Chemical Co., Ltd.) 15 parts by weight of SBR zwitterionic latex (Acostar C177, manufactured by Mitsui Cytec) Wheat starch (AS-225, manufactured by Chiba Starch Co., Ltd.) 8 parts by weight Precipitable synthetic silica (Mizukasil P-527, manufactured by Mizusawa Chemical Industry Co., Ltd.) 26 parts by weight Polyvinyl alcohol (PVA-105, manufactured by Kuraray Co., Ltd.) 5 parts by weight Auxiliary agent (dispersant, lubricant, defoamer, wetting) 1 part by weight

Example 5 A pressure-sensitive adhesive sheet (a confidential postcard for tri-fold postcards) was obtained in the same manner as in Example 1 except that the paint for the re-peelable surface was prepared as follows. "Re-release surface for paint formulations" amount nonionic surfactant polymerized acrylic adhesive using a (Rikabondo AP-P 0022-6, manufactured by Central Rika Co., Ltd.) of 35 parts by weight of secondary amino groups hydrochloride Copolymer of diallylamine hydrochloride and acrylamide as resin to be contained (Sumireze resin 1001, manufactured by Sumitomo Chemical Co., Ltd.) 3 parts by weight SBR amphoteric ion latex (Acostar C177, manufactured by Mitsui Cytec) 20 parts by weight Wheat starch ( AS-225, Chiba Starch Co., Ltd.) 10 parts by weight Precipitable synthetic silica (Mizukasil P-527, manufactured by Mizusawa Chemical Industry Co., Ltd.) 26 parts by weight Polyvinyl alcohol (PVA-105, Kuraray Co., Ltd.) 5 parts by weight Auxiliary agent (dispersant) , Lubricant, defoamer, wetting agent) 1 part by weight

Example 6 A pressure-sensitive adhesive sheet (a confidential three-fold postcard) was prepared in the same manner as in Example 1 except that the recoatable surface paint prepared in Example 1 was applied to both sides of high-quality paper. Postcard).

Comparative Example 1 A pressure-sensitive adhesive sheet (confidential postcard for tri-fold postcard) was obtained in the same manner as in Example 1 except that the paint for the re-peelable surface was prepared as follows. 35 % by weight of acrylic-modified natural rubber-based latex (Flutite FB-DO-3, manufactured by Mitsui & Co., Ltd. Solvent Coating Co., Ltd.) Anionic SBR latex (Polylac 750K-101, manufactured by Mitsui Chemicals, Inc.) 20 parts by weight Wheat starch (AS-225, manufactured by Chiba Starch Co., Ltd.) 10 parts by weight Precipitated synthetic silica (Mizukasil P-527, manufactured by Mizusawa Chemical Industry Co., Ltd.) 29 parts by weight Polyvinyl alcohol (PVA-105, manufactured by Kuraray Co., Ltd.) 5 1 part by weight Auxiliary agent (dispersant, lubricant, defoamer, wetting agent)

Comparative Example 2 A pressure-sensitive adhesive sheet (a confidential postcard for tri-fold postcards) was obtained in the same manner as in Example 1 except that the paint for the re-peelable surface was prepared as follows. "Removable surface paint compounding" compounding amount Acrylic ester copolymer (AE-923, manufactured by Nippon Synthetic Rubber Co.) 60 parts by weight Wheat starch (AS-225, manufactured by Chiba Starch Co., Ltd.) 50 parts by weight Synthetic amorphous silica (Fanseal X37B, manufactured by Tokuyama Soda Co.) 50 parts by weight Cationic compound having quaternary ammonium group (styrene-triethylammonium acrylate copolymer) 40 parts by weight

Comparative Example 3 A pressure-sensitive adhesive sheet (a confidential postcard for tri-fold postcard) was obtained in the same manner as in Example 1 except that the paint for the re-peelable surface was prepared as follows. Amount of “paint for removable surface” Amount Acrylic-modified natural rubber-based latex (Furutite FB-DO-3, manufactured by Mitsui & Co., Ltd., Solvent Coating Co.) 60 parts by weight Calcium carbonate (Softon 1000, manufactured by Bihoku Powder Chemical Industry Co., Ltd.) 50 Parts by weight Synthetic amorphous silica (Fanseal X37B, manufactured by Tokuyama Soda Co., Ltd.) 50 parts by weight Cationic compound having a tertiary amino group (styrene-ethyl diethyl acrylate amine copolymer) 40 parts by weight

Comparative Example 4 An acrylamide / diallylamine copolymer as a cation resin was dried on a support having a basis weight of 115 g / m ^{2 formed} by a fourdrinier paper machine at a dry adhesion amount of 0.8 g / m ² , and the phosphorylated starch was dried. Using an on-machine size press device, the substrate was adhered to the front and back sides so that the amount of adhesion 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. Amount of “coating for removable surface” Acrylic ester copolymer (AE-923, manufactured by Nippon Synthetic Rubber Co.) 60 parts by weight Wheat starch (AS-225, manufactured by Chiba Starch Co., Ltd.) 40 parts by weight Synthetic silica (Mizukasil P) -832, manufactured by Mizusawa Chemical Industries) 50 parts by weight

"Evaluation method" (1) Adhesion of the adhesive layer to the substrate sheet The adhesive layer was rubbed with a finger, and the adhesion to the substrate sheet was visually evaluated. A: The adhesive layer is not peeled off at all. ：: Part of the adhesive layer is peeled off. Δ: The adhesive layer was slightly peeled off, but at a level that was not problematic in practical use. X: This is a level at which the adhesive layer is peeled off and poses a practical problem.

(2) Evaluation of Water Resistance of Print Yellow, magenta, cyan and black were printed on the releasable surface using an ink jet printer MC-830 (manufactured by Seiko Epson Corporation), and the ink was dipped in water for 2 minutes. Bleeding was evaluated visually. A: Excellent without bleeding. ：: Almost no bleeding. Δ: Slight bleeding observed, but no practical problem. ×: There is bleeding, and there is a problem in practical use. XX: Remarkable bleeding

(3) Evaluation of paint stability Adhesives, pigments, cationic resins, auxiliaries, etc. were blended and agitated to prepare the paint used in the present invention. Observed. ：: No change and stable. Δ: Viscosity slightly increased, but at a level without any problem. ×: Viscosity increased sharply, or aggregates were generated and unstable. (4) Adhesion / Removability of Removable Surface Using a dry sealer (manufactured by Toppan Forms Co., Ltd.), the obtained tri-fold postcard sample is cut into an appropriate size so that the removable surfaces face each other. Z-fold, 23 ° C, 65
% After adjusting the humidity for 24 hours under the temperature and humidity condition of 1%.
Passed through a press roll set to 50 μm and crimped,
I made a confidential postcard. The obtained confidential postcard was peeled again by T-peeling, and the state of peeling and the state of the peeled surface were evaluated. ：: Removable. Good. Δ: Removable, but weak adhesive strength or partial substrate breakage, but practically acceptable. X: Destruction of the base material or peeling with low adhesive strength, which is a practically problematic level.

(5) Evaluation of ink jet suitability Using an ink jet printer MC-830 (manufactured by Seiko Epson Corporation), yellow, magenta, cyan, and black were printed in halftone dots, and the dot shape was observed with a stereoscopic microscope, and ink bleeding was visually observed. Was evaluated. ：: The shape of the dots was not distorted and there was no problem at all. Δ: The shape of the dots is slightly distorted, but there is no practical problem. X: The dot was largely disintegrated, causing a practical problem.

(6) Comprehensive Evaluation Comprehensive evaluation as confidential postcard paper was performed. A: Very excellent as a confidential postcard. ：: Excellent as confidential postcard paper. Δ: There are some problems as confidential postcards, but there is no practical problem. ×: There is a problem as a confidential postcard, and it is at a level that cannot be used practically.

[0057]

[Table 1]

[0058]

In the pressure-sensitive adhesive sheet having the base sheet according to the present invention and an adhesive layer on at least one surface, a primary amino group or an addition salt thereof and a secondary amino group or an addition thereof are contained in the adhesive layer. By containing at least one kind of cationic compound selected from salts, it is suitable for an ink jet printer, in particular, has less bleeding of printing ink, has excellent water resistance of printing, and has adhesion and re-peeling when used as confidential postcard paper. A pressure-sensitive adhesive sheet satisfying the properties is obtained. A primary amino group or an addition salt thereof;
When a cationic compound having a tertiary amino group or an addition salt thereof is used, the stability of the coating is superior to a cationic compound having a tertiary amino group or a quaternary amino group, and the resulting pressure-sensitive adhesive sheet The recording has excellent light fastness.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09J 133/26 C09J 201/00 201/00 201/02 201/02 B41J 3/04 101Y F-term (Reference) 2C005 WA03 2C056 FC06 2H086 BA15 BA31 BA35 BA37 4J004 AA04 AA05 AA08 AA09 AA10 AA14 AB01 CA02 CA08 CB01 CB02 CB03 CC02 CC04 CE02 DB02 EA05 4J040 BA041 BA042 DD021 DD022 DD051 DF0103 DF041 DF041 DF041 GA

Claims (6)

[Claims] An adhesive layer containing an adhesive and an adhesion control agent is provided on at least one surface of a base sheet, and the adhesive layer is subjected to a high pressure treatment with the adhesive layers facing each other. A pressure-sensitive adhesive sheet whose adhesive surface can be peeled off, wherein the adhesive layer is at least one member selected from a primary amino group or an addition salt thereof and a secondary amino group or an addition salt thereof. A pressure-sensitive adhesive sheet comprising a cationic compound of the formula (I): 2. The pressure-sensitive adhesive sheet according to claim 1, wherein the cationic compound is contained in an amount of 1 to 70% by weight of the solid content of the adhesive layer. 3. The pressure-sensitive adhesive sheet according to claim 1, wherein the adhesive layer further contains an amphoteric resin having both cationic and anionic functional groups in one molecule. . 4. The pressure-sensitive adhesive sheet according to claim 1, further comprising a hydrophilic polymer in the adhesive layer. 5. The pressure-sensitive adhesive sheet according to claim 1, wherein the cationic compound has a secondary amino group or an addition salt thereof. 6. The pressure-sensitive adhesive sheet according to claim 5, wherein the cationic compound having a secondary amino group or an addition salt thereof is a copolymer of diallylamine and (meth) acrylamide or an addition salt thereof.