JP2004106547A - Base sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base sheet which alleviates at least either a problem of the water resistance of a print that a water-based dye of an ink jet printer is eluted into water when the water sticks to a printed part after recording is performed by using the printer of an ink jet system and a problem of the transferability of a print that the print is transferred onto the other side subjected to contact bonding, on the occasion when the side subjected to ink jet recording is contact-bonded and then peeled off, and which is excellent in suitability for offset printing and has a high general performance. <P>SOLUTION: The base sheet has an adhesive layer formed by applying a cold seal adhesive which contains an adhesive constituent (A) containing at least one kind selected from a natural rubber latex, a modified natural rubber latex and a synthetic rubber latex, an acetoacetylated polyvinylalcohol (B) and a specific amphoteric polymer (C) obtained by radically polymerizing a monomer mixture comprising an anionic monomer (D) and a cationic monomer (E). <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a cold seal adhesive, that is, an adhesive that does not cause tack on a coated surface to which the adhesive is applied in a normal state, and the coated surface is another surface to which the adhesive is applied. Even if the two adhesive layers are stacked so that they are in contact with each other, the adhesive does not cause adhesion and blocking.However, it is possible to bond the two by applying a certain pressure or more to the two surfaces. And an adhesive that forms a layer of adhesive that can be removed again after bonding.

In recent years, various information, for example, personal information, print information, or information that requires confidentiality, confidentiality, or concealment of print information or the like, or does not necessarily require confidentiality of advertisement or advertisement, etc. By printing information on a base sheet, information carriers containing such information are becoming widespread.

Here, the "information carrier" means various kinds of information, for example, personal information or printed information, on a continuous (for example, continuous paper wound on a roll) or a cut sheet (for example, stacked sheets). Information that requires confidentiality, confidentiality or concealment of information, or information that does not necessarily require confidentiality, such as advertisements and advertisements, is included, for example, by handwriting or printing. A medium, which is an information medium in the form of, for example, a postcard, an envelope, a business form, a delivery slip, a communication card, a folding card, an overlapping sheet, or an information hiding sheet. Note that an envelope or the like is not necessarily printed with information, and should be an information container for containing an information medium, but is included in the above information carrier in this specification.

Among such information carriers, a postcard (so-called confidential postcard) in which a base sheet on which necessary information is recorded is folded with the surface on which the information is recorded inward to impart confidentiality (so-called confidential postcard) is typical.
In the present specification, the term “base sheet” refers to a sheet-shaped base material that is usually used for an information carrier. As the base sheet, for example, normal paper, cloth, synthetic paper, polyester-based resin, A film such as an acetate resin, a triacetate resin, an acrylic resin, a polycarbonate resin, a polyvinyl chloride resin, a polyimide resin, cellophane, and celluloid can be used. Further, the “substrate sheet” includes coated paper or cast coated paper provided with a coating layer in advance, and laminated paper obtained by laminating a resin film on the paper surface or processing with a molten resin.

基 体 Usually, an adhesive called a cold seal adhesive is applied to the base sheet of such a confidential postcard before recording information. Next, information common to the confidential postcards is printed on the coated surface using a printing method such as offset printing and gravure printing. The order of printing and coating may be changed. Thereafter, specific individual information such as each personal information is recorded. Furthermore, the printed surface on which the information is printed is overlapped with the other surface coated with the cold seal adhesive so that the adhesive layers on both surfaces are in contact with each other, and bonded by applying a certain pressure or more, As a result, it is possible to form a laminate in which the secret information is hidden (not visible from the outside), that is, a confidential postcard. This confidential information can be read by peeling off the adhered surface again, but the surface once peeled will not adhere unless a certain pressure or more is applied again. Does not return to the state of the body. As a result, the confidential postcard can maintain confidentiality.

By the way, in this specification, "printing" means writing common information and a pattern using any general printing method such as offset printing and gravure printing. Is printing of information and patterns using a so-called ink jet printer, and means, for example, writing non-common personal information and the like.
Further, in the present specification, the “adhesive layer” refers to an adhesive layer in a solvent-free (dry) state.

Such cold seal adhesives require the following basic properties:
Under normal conditions, no tack occurs on the coated surface with adhesive;
In a normal state, even if the adhesive layers of the two coated surfaces on which the adhesive is applied are overlapped so that both adhesive layers are in contact with each other, adhesion and blocking do not occur;
The two layers can be adhered by applying a certain level of pressure to the overlap of the two layers;
The adhered surface can be removed again;
Once peeled, the surfaces that have been bonded will not bond (in a normal state) unless a certain pressure is applied again.

In this specification, the “normal state” means that no special operation such as pressurizing is applied to the base sheet coated with the adhesive, for example, a cold seal adhesive is applied to the base sheet. When the coated surfaces that have been processed are stacked and left or stored, when the stacked base sheets are strongly pressed by hand or when information is printed on those coated surfaces, a low pressure (approximately 7,840 N / m) is applied. ² or less).

Such cold seal adhesives further require the following additional properties:
Printing on the adhesive layer formed by applying the adhesive to the base sheet (hereinafter also referred to as "first coating"), or applying the adhesive on the printing of the base sheet That the adhesive layer can be formed (hereinafter also referred to as “post-coating”);
Further, specific information such as personal information can be recorded on the adhesive layer;
Bonding can be released by peeling the bonded base sheets by a force that is usually pulled by a human hand to separate them from each other;
The information on the surface from which the bonding has been released must be completely readable, that is, the base sheet will not be destroyed when the bonding is released (hereinafter also referred to as "removable").

Conventionally, as a method of recording specific information such as personal information on such a confidential postcard, a laser beam printer has been mainly used. On the other hand, in recent years, an ink jet printer using a water-soluble dye has come to be used because the processing speed is high and it is possible to cope with recording of a small lot.

However, if cold seal adhesives compatible with conventional laser beam printers (hereinafter referred to as “conventional cold seal adhesives”) are used as they are in ink jet printers, there is a problem with the quality of ink jet recorded prints. It has been found to occur. (I) When water adheres to the printed portion, the water-soluble dye (hereinafter, referred to as "water-based dye") of the ink jet printer elutes into the water, which makes it difficult to read information. And (ii) when the surface on which the ink jet recording is performed is press-bonded and then the surface is peeled off, there arises a problem of print transferability that the ink jet recorded print is transferred to the opposite surface.
In this specification, “recording, inkjet recording, or recording using an inkjet printer” includes, in addition to recording using an achromatic color such as black, full-color using a chromatic color such as red, blue, green, and yellow. Records are also included.

The above problem is caused by the fact that the aqueous dye contained in the print is difficult to fix to the conventional cold seal adhesive.
Usually, an aqueous dye has a salt of a sulfonic acid group and / or a carboxyl group in the dye molecule, and the salt is made water-soluble. Thus, aqueous dyes include negatively charged anionic molecules.
On the other hand, the conventional cold seal adhesive is also an anionic dispersion system, and the adhesive component is negatively charged. Examples of such an adhesive component include natural rubber, modified natural rubber, and synthetic rubber.
Therefore, it is considered that the aqueous dye and the adhesive component of the conventional cold seal adhesive are both negatively charged and do not attract each other electrically, so that it is difficult for the aqueous dye to be fixed to the conventional cold seal adhesive.

By the way, special printing paper is used for printing paper of an ink jet printer in order to impart water resistance to ink jet recorded prints. That is, a positively charged cationic polymer is introduced into the ink receiving layer of the printing paper. In this method, negatively charged dye molecules are captured by the positive charge of the cationic polymer, and the dye molecules are fixed to the ink receiving layer by Coulomb force by evaporation of water.

Examples of the cationic polymer to be introduced into the ink receiving layer include quaternized polyvinyl pyridine, polyethylene imine, quaternized polyethylene imine, polyallyl sulfone, dicyandiamide condensate, polyethylene polyamine-based polymer, polyallylamine, polydiallylamine, and alkyl. Amine-epichlorohydrin condensate, polyamine-epichlorohydrin-based polymer, polyalkylene polyurea, polyamide polyurea, dimethylallylammonium chloride, cationic vinyl copolymer and the like have been disclosed (JP-A-7-315632 and JP-A-8-81532). -51487).

Therefore, it was expected that a cold seal adhesive suitable for ink jet recording could be obtained based on the idea that water resistance and non-transfer properties could be imparted to ink jet recorded prints in the same manner.
For example, Japanese Patent Application Laid-Open No. H10-52985 discloses a cold seal adhesive suitable for ink jet recording by adding a cationic polymer commonly used for recording paper for an ink jet printer to a conventional cold seal adhesive. Are disclosed. However, it is described that although the water resistance and non-transferability of the ink-jet recorded prints are improved, the viscosity of the cold seal adhesive is largely thixotropic and the properties are not always stable. Furthermore, in this method, since the cationic polymer has high water solubility, there is also a problem of offset printing suitability such as soiling the offset plate during offset printing.

Japanese Patent Application Laid-Open No. Hei 9-71758 discloses a weak cationic polymer which can maintain the system stability relatively well even when added to a modified natural rubber which is an adhesive component of a conventional cold seal adhesive. It discloses a method of obtaining a cold seal adhesive suitable for inkjet recording by adding it to a cold seal adhesive. However, in this method, since the cationicity of the polymer to be added is weak, if the amount is small, sufficient water resistance and non-transfer property cannot be imparted to ink-jet recorded prints. Therefore, when the amount of the weak cationic polymer added is increased, a problem that the adhesive strength is reduced occurs. Therefore, with this method, it is difficult to easily obtain a cold seal adhesive suitable for ink jet recording having well-balanced properties.

In fact, the present inventors also confirmed that the addition of a cationic polymer to a conventional cold seal adhesive destabilizes the dispersion of the cold seal adhesive. Further, in order to improve the water resistance and non-transferability of the ink jet recorded print, the amount of the cationic polymer added to the conventional cold seal adhesive is increased, and the cold seal adhesive is immediately or during storage. It was also confirmed that the viscosity increase, aggregate generation and / or gelation of the resulting product made it impossible to use it as a cold seal adhesive.

Therefore, simply adding a conventionally used cationic polymer to a conventional cold seal adhesive improves the water resistance of ink-jet recorded prints, and improves the transferability of prints upon re-peeling. It can be said that it is difficult to obtain a cold seal adhesive suitable for ink jet recording, which has a low offset printing suitability.

印字 In addition, many studies have been made to include a filler in a cold seal adhesive in order to improve the color development and obtain water resistance of ink-jet recorded prints. However, when the filler is added in a large amount, when offset printing is performed on paper coated with the cold seal adhesive, the adhesive formed temporarily by the cold seal adhesive by a so-called fountain solution used for printing is used. The strength of the layer decreases. As a result, there is the problem that a portion of the cold seal adhesive layer containing the filler may flake off the coated paper surface and contaminate the printing plate. Further, for the same reason, in a turn bar of a printing / form processing line, there is a problem that a layer of a cold seal adhesive applied and formed on a base sheet may fall off due to abrasion and contaminate a printing plate. .

The present invention has been made in order to solve such a problem, and the problem is to apply a cold seal adhesive to a surface to be printed of a base sheet, dry it, print information, and print an inkjet printer. After using and recording, or after printing information on the surface of the base sheet to be printed, apply a cold seal adhesive, dry and record using an ink jet printer, and then water is printed on the printing part. The water-soluble dye of the inkjet printer elutes in water even if it adheres, and the problem of water resistance of the print, and the transferability of the print that the print is transferred to the other press-bonded surface when the ink-jet recorded surface is peeled off after pressing. At least one of the problems described above is alleviated, preferably substantially eliminated, and the offset printing suitability is also good, and these characteristics are easily adjusted appropriately. DOO can, is that the overall performance provides a high cold seal adhesive.

According to one aspect of the present invention, there is provided a new cold seal adhesive, which comprises:
Adhesive component (A) comprising at least one selected from natural rubber latex, modified natural rubber latex, and synthetic rubber latex, and acetoacetylated polyvinyl alcohol (B)
Wherein the cold seal adhesive is particularly suitable for inkjet recording.
In the following description of the present specification, unless otherwise specified, a part that does not consider a solvent is based on parts by weight and% by weight.

The cold seal adhesive of the present invention comprises an adhesive component (A) comprising at least one selected from natural rubber latex, modified natural rubber latex, and synthetic rubber latex, and acetoacetylated polyvinyl alcohol (B). Therefore, at least one of the problems of water resistance and non-transferability of ink-jet recorded prints is alleviated, preferably substantially eliminated, and the cold seal adhesive of the present invention is excellent in offset printability and dispersible. Good stability, and excellent abrasion resistance of the adhesive layer formed by using the cold seal adhesive.

Furthermore, since the cold seal adhesive of the present invention further contains the amphoteric polymer (C), the ink jet recorded prints are excellent in water resistance.
Furthermore, since the cold seal adhesive of the present invention contains a cationic polymer, the ink jet recorded prints are more excellent in water resistance.

BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, the "adhesive component (A)" is a component which comprises at least one selected from natural rubber latex, modified natural rubber latex, and synthetic rubber latex, and is a component having a main adhesive force. And (A) those used as an adhesive component of a conventional cold seal adhesive can be used.
Specific examples of such an adhesive component (A) include those disclosed in JP-A-5-295335, JP-A-5-186640, and JP-A-9-310055. It can be appropriately selected according to the desired properties and used as (A) in the present invention. In addition, the contents of these specifications constitute the contents of this specification by this citation.

Here, "natural rubber latex" refers to an emulsion of a rubber produced in nature, which is usually referred to as "natural rubber latex", and can be used to obtain the intended cold seal adhesive of the present invention. As long as it is not particularly limited.

Further, the term "modified natural rubber latex" refers to a natural rubber latex in which the properties have been modified by addition polymerization (or radical polymerization) of a natural rubber latex using a compound having an ethylenic carbon-carbon double bond, and usually " It is called "modified natural rubber latex" and is not particularly limited as long as the intended cold seal adhesive of the present invention can be obtained.

Examples of the modified natural rubber latex include natural rubber latex modified by addition polymerization of natural rubber latex with alkyl (meth) acrylates and various compounds having a double bond between ethylenic carbon atoms such as styrene. can do. Specifically, an acrylic-modified natural rubber latex modified by copolymerizing alkyl (meth) acrylates can be exemplified (see JP-A-5-295335). (In the present specification, acrylic acid and methacrylic acid are also collectively referred to as “(meth) acrylic acid”.)
In addition, the type of the compound to be addition-polymerized and the amount to be copolymerized can be appropriately selected for the modified natural rubber latex according to desired properties.
The modified natural rubber latex can be produced by a known method, but a commercially available product may be used.
Moreover, the modified natural rubber latex can be used alone or in combination.

“Synthetic rubber latex” refers to an emulsion of synthetic rubber, and is not particularly limited as long as the intended cold seal adhesive of the present invention can be obtained. Examples of the synthetic rubber latex include styrene-butadiene rubber (SBR) latex, nitrile-butadiene rubber (NBR) latex, methyl methacrylate-butadiene rubber (MBR) latex, and neoprene latex (Japanese Patent Application Laid-Open No. 5-186640). reference).
The synthetic rubber latex can be produced using a known method, but a commercially available product may be used.
The synthetic rubber latex can be used alone or in combination.

In the present invention, “acetoacetylated polyvinyl alcohol (B)” is acetoacetylated polyvinyl alcohol, which has a highly reactive acetoacetyl group in a side chain, and thus forms a film having excellent water resistance. It has the function of
The acetoacetylated polyvinyl alcohol (B) is not particularly limited as long as the desired cold seal adhesive of the present invention can be obtained.

The polymerization degree of the acetoacetylated polyvinyl alcohol (B) is preferably from 500 to 2,000.
Further, the saponification degree of the acetoacetylated polyvinyl alcohol (B) is particularly preferably 90 mol% or more.
Incidentally, (B) may contain polyvinyl alcohol which is not acetoacetylated.

The acetoacetylated polyvinyl alcohol (B) can be produced by a known method, but a commercially available product can be used. Such acetoacetylated polyvinyl alcohol (B) is commercially available, for example, from Nippon Synthetic Chemical Industry Co., Ltd. under the trade names Gosefimer Z100, Z200, Z200H, Z210, and Z320.
The acetoacetylated polyvinyl alcohol (B) can be used alone or in combination.

The cold seal adhesive of the present invention preferably contains 5 to 25 parts by weight of acetoacetylated polyvinyl alcohol (B) based on 100 parts by weight of the adhesive component (A).
The parts by weight of the adhesive component (A) and the acetoacetylated polyvinyl alcohol (B) are based on a portion of the adhesive component (A) and the acetoacetylated polyvinyl alcohol (B) that does not consider the solvent.

The cold seal adhesive of the present invention preferably further comprises an amphoteric polymer (C).
In the present invention, the “amphoteric polymer (C)” is a monomer mixture containing “anionic monomer (D)” and “cationic monomer (E)” as essential components. Amphoteric polymer obtained by copolymerizing (addition polymerization or radical polymerization) a monomer mixture which may contain the polymerizable monomer (F), and having an anionic group and a cationic group simultaneously. Polymer.

Here, the “anionic monomer (D)” is a compound having an anionic group and an ethylenic double bond between carbon atoms, and is subjected to a polymerization reaction (addition polymerization or addition polymerization) with a target amphoteric polymer (C). (Radical polymerization) means a compound that provides an anionic group.

As used herein, the term “anion group” refers to a functional group having a negative charge (eg, —COO 2 ^— and —SO ₃ ^— ) (a functional group in which the negative charge is electrically neutralized by a counter cation (eg, -COO ^- Na ⁺ and -SO ₃ ^- containing K ^+, etc.)) and a functional group capable of forming a functional group having a negative charge and release hydrogen ions in water (e.g., -COOH and -SO ₃ H and the like) Say. The “functional group having a negative charge” and the “functional group capable of forming a functional group having a negative charge by releasing hydrogen ions in water” change the state around each functional group, such as pH. It is needless to say that they can be easily converted to each other. Regarding the “anion group” in the present invention, these functional groups can be used alone or in combination depending on the characteristics of the amphoteric polymer (C).

Here, as the “functional group having a negative charge (including a functional group in which the negative charge is electrically neutralized by a counter cation)”, for example, a carboxylate group (—COO ⁻ and —COOM ¹ ), a sulfonate group (-SO ₃ ^- and -SO ₃ M ^2), and phosphate groups _{^{(-PO 4 H -, -PO 4}} 2- , and -PO ^₄ M ³ M ₄₎ or the like can be exemplified [where, M ^1, M ² , M ³ , and M ⁴ are an alkali metal, an alkaline earth metal, or ammonium (note that one of M ³ and M ⁴ may be hydrogen)].
Further, as the “functional group capable of forming a functional group having a negative charge by releasing hydrogen ions in water”, for example, a carboxyl group (—COOH), a sulfonic acid group (—SO ₃ H), and a phosphate group (− PO ₄ H ₂ ).

As used herein, the term "ethylenic double bond between carbon atoms" refers to a double bond between carbon atoms capable of undergoing a polymerization reaction (addition polymerization or radical polymerization). As a double bond between such ethylenic carbon atoms, for example, a vinyl group _{(CH 2 = CH -),} ( meth) allyl group _{(CH 2 = CH-CH 2} - and _{CH 2 = C (CH 3)} - CH ₂ —), (meth) acryloyloxy groups (CH ₂ ＣＨCH—COO— and CH ₂ ＣC (CH ₃ ) —COO—), and —COO—CH ＝ CH—COO—.

Examples of such “anionic monomer (D)” include the following compounds:
(D1) A compound having a carboxyl group and an ethylenic carbon atom double bond, such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, and a half ester of maleic acid, and a carboxylic acid salt group and an ethylenic carbon atom A compound having a double bond;
(D2) a compound having a sulfonic acid group such as styrenesulfonic acid and a double bond between ethylenic carbon atoms, and a compound having a sulfonic acid group and a double bond between ethylenic carbon atoms;
(D3) Compounds having a phosphate group and an ethylenic double bond between carbon atoms, such as (meth) acrylic acid oxyethylamide phosphate, and compounds having a phosphate group and a double bond between ethylenic carbon atoms.

The counter cation of the carboxylate, sulfonate, and phosphate groups is preferably an ammonium ion, an alkali metal ion, or the like, and particularly preferably an ammonium ion, a potassium ion, or a sodium ion.
Particularly, acrylic acid and methacrylic acid are preferred as the anionic monomer (D).
These anionic monomers (D) can be used alone or in combination depending on the intended properties of the amphoteric polymer (C).

Further, the “cationic monomer (E)” is a compound having a cationic group and an ethylenic double bond between carbon atoms, and is subjected to a polymerization reaction (addition polymerization or radical polymerization) with a target amphoteric polymer (C). (Polymerization) means a compound that will provide a cationic group.

As used herein, the term “cationic group” refers to a functional group having a positive charge (eg, —N ⁺ (CH ₃ ) ₃ and —C ₅ H ₄ N ⁺ —CH ₃ ) (electrically neutralized by a counter anion) has been that functional groups _{^{(e.g., -N + (CH 3) 3}} Cl - and _{^{-C 5 H 4 N + -CH 3}} Br - , etc.) refers to including) the receptor to positively charged hydrogen ions in water functional group (e.g., -N (CH _{3) 2} and -C ₅ H ₄ N, etc.) capable of forming a functional group having including. These “functional groups having a positive charge” and “functional groups that can receive a hydrogen ion in water to form a functional group having a positive charge” change the state around each functional group, such as pH. It is needless to say that they can be easily converted to each other. As for the “cation group” in the present invention, these functional groups can be used alone or in combination depending on the intended properties of the amphoteric polymer (C).

Here the "functional group having a positive charge", for example, ammonium salt ^{((-NR 3 R 4 R 5} ) + and ^{(-NR 3 R 4 R 5)} + X -) and pyridinium bases ((-C ₅ H ₄ N—R ⁶ ) ⁺ and (—C ₅ H ₄ N—R ⁶ ) ⁺ X ⁻ ) [provided that R ³ , R ⁴ , R ⁵ and R ⁶ are hydrogen, methyl group, ethyl group , A benzyl group, a phenyl group, or a methylphenyl group, and X ^- is a halogen ion such as a chloride ion and a bromide ion, an acetate ion (CH ₃ COO ⁻ ), a sulfate ion (SO ₄ ^2- ), and a nitrate ion (NO ₃ ⁻ ), perchlorate ion (ClO ₄ ⁻ ), methyl sulfate ion (CH ₃ SO ₄ ⁻ ), ethyl sulfate ion (C ₂ H ₅ SO ₄ ⁻ ), and p-toluenesulfonic acid ion (CH ₃ C ₆ H ₄ SO ₃ ⁻ ) and the like].

Further, as the “functional group capable of forming a functional group having a positive charge by receiving a hydrogen ion in water”, for example, an amino group (—NR ⁷ R ⁸ ) wherein R ⁷ and R ⁸ are hydrogen, methyl group , an ethyl group, a benzyl group, a phenyl group or a methylphenyl group] and pyridyl group, (-C ₅ H ₄ N) can be exemplified.
The "ethylenic carbon double bond" is the same as described in the description of "anionic monomer (D)".

Examples of such “cationic monomer (E)” include the following compounds:
(E1) a compound having a primary amino group and an ethylenic carbon-carbon double bond, and a compound having a primary ammonium base and an ethylenic carbon-carbon double bond;
(E2) a compound having a secondary amino group and an ethylenic carbon double bond, and a compound having a secondary ammonium base and an ethylenic carbon double bond;
(E3) a compound having a tertiary amino group and an ethylenic carbon double bond, and a compound having a tertiary ammonium base and an ethylenic carbon double bond;
(E4) a compound having a quaternary ammonium base and an ethylenic carbon-carbon double bond;
(E5) Compounds having a pyridyl group and a double bond between ethylenic carbon atoms, and compounds having a pyridinium base and a double bond between ethylenic carbon atoms.

The following compounds are more preferred as the "cationic monomer (E)":
As (E1), for example,
(Meth) acrylic acid esters having a primary amino group, and (meth) acrylic acid esters in the form of their salts having a primary ammonium base;
As (E2), for example,
(Meth) acrylic acid esters having a secondary amino group, and (meth) acrylic acid esters in the form of their salts having a secondary ammonium base;
As (E3), for example,
2- (N, N-dimethylamino) ethyl (meth) acrylate, 2- (N, N-diethylamino) ethyl (meth) acrylate, 2- (N, N-dibutylamino) ethyl (meth) acrylate, 3- (N, N-dimethylamino) propyl (meth) acrylate, 2- (N, N-methylethylamino) ethyl (meth) acrylate, 2- (N, N-ethylbutylamino) methacrylate ) Ethyl and (meth) acrylic acid esters such as 2- (N, N-ethylbenzylamino) ethyl (meth) acrylate having a tertiary amino group, and (meth) in the form of their salts A compound which is an acrylate ester and has a tertiary ammonium base,
(Meth) acrylamides such as 3- (N, N-dimethylamino) propyl (meth) acrylamide and compounds having a tertiary amino group, and (meth) acrylamides in the form of their salts and tertiary ammonium bases A compound having:
As (E4), for example,
2- (N, N-dimethylamino) ethyl methyl chloride salt of (meth) acrylic acid, 2- (N, N-dimethylamino) ethyl benzyl chloride (meth) acrylate, and 3- (N) (meth) acrylic acid (Meth) acrylic acid esters such as N, N-dimethylamino) propylepichlorohydrin hydrochloride and having a quaternary ammonium base;
(Meth) acrylamide, such as 3- (N, N-dimethylamino) propyl (meth) acrylamide epichlorohydrin hydrochloride, having a quaternary ammonium base;
As (E5), for example,
(Meth) acrylic esters such as 2- (4-pyridyl) ethyl (meth) acrylate, 3- (4-pyridyl) propyl (meth) acrylate, and 4- (4-pyridyl) butyl (meth) acrylate A compound having a pyridyl group,
2- (N-methylpyridinium) ethyl chloride (meth) acrylate, 2- (N-ethylpyridinium) ethyl bromide (meth) acrylate, 2- (N-butylpyridinium) ethyl chloride (meth) acrylate, (meth) acrylate A) a (meth) acrylate ester such as 3- (N-methylpyridinium) propyl chloride acrylate and 2- (N-benzylpyridinium) ethyl chloride (meth) acrylate, which has a pyridinium base;
Compounds having a vinyl group and a pyridyl group such as vinylpyridine, and compounds having a vinyl group and a pyridinium base such as N-methylvinylpyridinium chloride, N-ethylvinylpyridinium chloride, and N-phenylvinylpyridinium chloride.

In addition, as a counter anion of the above-mentioned ammonium base and pyridinium base, a halogen ion such as a chloride ion and a bromide ion, an acetate ion, a sulfate ion, a nitrate ion, a perchlorate ion and the like can be exemplified.
These cationic monomers can be used alone or in combination depending on the intended properties of the amphoteric polymer (C).

Further, among the above-mentioned cationic monomers, when the substrate sheet on which the cold seal adhesive of the present invention is applied to form an adhesive layer is used for an inkjet printer, sufficient water resistance for the inkjet aqueous dye is required. In order to impart the property, "at least one selected from the above (E3) and (E4)" is preferably contained in the above-mentioned cationic monomer in an amount of 10 to 100% by weight, and 50 to 100% by weight. %, More preferably 80 to 100% by weight.

When used in this inkjet printer, the following compounds are more preferred as at least one selected from the above (E3) and (E4):
Compounds having a tertiary amino group, such as (meth) acrylates such as 2- (N, N-dimethylamino) ethyl (meth) acrylate and 2- (N, N-diethylamino) ethyl (meth) acrylate ;
2- (N, N-dimethylamino) ethyl methyl chloride salt of (meth) acrylic acid, 2- (N, N-dimethylamino) ethyl benzyl chloride (meth) acrylate, and 3- (N) (meth) acrylic acid (Meth) acrylic acid esters having a quaternary ammonium salt group, such as N, N-dimethylamino) propylepichlorohydrin hydrochloride; and 3- (N, N-dimethylamino) propyl (meth) acrylamidoepichlorohydrin hydrochloride, etc. (Meth) acrylamide compounds having a quaternary ammonium base.

When used in an inkjet printer, at least one selected from the above (E3) and (E4) is, in particular, 2- (N, N-dimethylamino) ethylmethyl chloride (meth) acrylate, (meth) acrylate ) 3- (N, N-dimethylamino) propyl epichlorohydrin hydrochloride, 3- (N, N-dimethylamino) propyl (meth) acrylamide epichlorohydrin hydrochloride, and (meth) acrylic acid 2- (N, N- Diethylamino) ethyl and the like are preferred.

The monomer mixture for obtaining the amphoteric polymer (C) preferably contains 2 to 30% by weight of the anionic monomer (D) and 50 to 98% by weight of the cationic monomer (E), More preferably, it contains 2 to 15% by weight of the anionic monomer (D) and 70 to 98% by weight of the cationic monomer (E).

The molar ratio (anion group / cation group) of the anion group of the “anionic monomer (D)” and the cationic group of the “cationic monomer (E)” contained in the monomer mixture is 10/90. ~ 30/70 is preferred.

Further, in the present invention, the monomer mixture may contain another polymerizable monomer (F).
Here, the "other polymerizable monomer (F)" refers to a compound other than the above-described anionic monomer (D) and cationic monomer (E), A compound having an ethylenic carbon-carbon double bond capable of copolymerizing (addition polymerization or radical polymerization) with the compound (D) and the cationic monomer (E).
The “ethylenic double bond between carbon atoms” is the same as that described in the description of “anionic monomer (D)”.

Examples of such “other polymerizable monomer (F)” include the following compounds:
(F1) Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, (meth) acrylic acid Alkyl (meth) acrylates such as 2-ethylhexyl, decyl (meth) acrylate, and dodecyl (meth) acrylate;
(F2) (meth) acrylates having an epoxy group such as glycidyl (meth) acrylate;
(F3) Styrene and derivatives of styrene such as styrene and vinyltoluene;
(F4) alkenes such as ethylene, and dienes such as butadiene and isoprene;
(F5) vinyl ester compounds such as vinyl acetate and vinyl propionate;
(F6) Chlorinated vinyl compounds such as vinyl chloride and vinylene chloride;
(F7) Compounds having a cyano group-containing ethylenic double bond between carbon atoms, such as acrylonitrile.
These other polymerizable monomers (F) can be used alone or in combination.

The amphoteric polymer (C) can be produced by polymerizing the above-mentioned monomer mixture (addition polymerization or radical polymerization) using a usual polymerization method and appropriately using a catalyst or the like. The polymerization reaction may be carried out in an aqueous solvent, but after polymerization in an organic solvent, the solvent may be converted to an aqueous solvent.
The reaction conditions such as reaction temperature, reaction time, type of solvent, type and concentration of monomer mixture, stirring speed, and type and concentration of catalyst are appropriately selected depending on the characteristics of the target amphoteric polymer and the like. What you get.

Here, the “catalyst” is a compound capable of causing a polymerization reaction of the monomer mixture by adding a small amount thereof, and is preferably a compound that can be used in an aqueous solvent and an organic solvent. For example, ammonium persulfate, sodium persulfate, potassium persulfate, t-butyl hydroperoxide, t-butyl peroxybenzoate, 2,2-azobisisobutyronitrile (AIBN), 2,2-azobis (2-diaminopropane) Examples thereof include hydrochloride and 2,2-azobis (2,4-dimethylvaleronitrile). Particularly, 2,2-azobisisobutyronitrile (AIBN) and 2,2-azobis (2- Diaminopropane) hydrochloride is preferred.

In the present invention, the “aqueous solvent” is mainly so-called water such as distilled water, ion-exchanged water, and pure water, but may appropriately contain a water-soluble organic solvent, for example, acetone and a lower alcohol. it can.
In the present invention, the "organic solvent" is not particularly limited as long as it does not substantially adversely affect the polymerization reaction and the properties as an adhesive, for example, methanol, ethanol, propanol, butanol, and ethyl acetate Etc., and combinations thereof.

The molecular weight of the amphoteric polymer (C) is not preferable when the weight average molecular weight is a low molecular weight of 5,000 or less and when the weight average molecular weight is a high molecular weight of 1,000,000 or more, because of its properties when blended into a cold seal adhesive.
Furthermore, in the present invention, the electrical properties of the amphoteric polymer (C), that is, the strength of the positive charge and the negative charge, the total charge, and the like are easily adjusted by appropriately selecting the composition of the monomer mixture into a preferable combination. can do. Therefore, it is easy to adjust the water resistance and non-transferability of the print in accordance with the type of the aqueous dye, so that a cold seal adhesive appropriately corresponding to the type of the aqueous dye can be easily provided.

In the cold seal adhesive of the present invention, the amphoteric polymer (C) preferably contains 10 to 120 parts by weight, more preferably 20 to 100 parts by weight, based on 100 parts by weight of the adhesive component (A). It is particularly preferred to contain from 30 to 90 parts by weight.
As described above, the parts by weight of the adhesive component (A) and the amphoteric polymer (C) are based on a portion of the adhesive component (A) and the amphoteric polymer (C) that does not consider the solvent.

The cold seal adhesive of the present invention may further comprise a particulate filler.
Here, the `` particulate filler '' is a particulate filler commonly used in cold seal adhesives, and is not particularly limited as long as it does not adversely affect the cold seal adhesive of the present invention. .
Examples of such a fine particle filler include amorphous silica, mica, calcium carbonate, kaolin, talc, diatomaceous earth, urea resin, styrene beads, calcined clay, cereal starch, and modified starch.

Furthermore, the fine particle filler is usually particles, preferably spherical, and its dimensions (diameter in the case of spherical) are not particularly limited as long as the intended performance of the present invention is exhibited.
These fine particle fillers can be used alone or in combination by appropriately selecting them according to the required properties.
By using the fine particle filler, it is possible to easily and suitably adjust properties such as adhesion, blocking resistance, printability, abrasion resistance, and adhesion to paper required for the cold seal adhesive. .

When recording the substrate sheet coated with the cold seal adhesive of the present invention to form an adhesive layer using an inkjet printer, it is preferable to use amorphous silica as the fine particle filler, In particular, it is preferable to use amorphous silica having an oil absorption of 100 ml / 100 g or more. In this case, the cold seal adhesive of the present invention preferably contains amorphous silica in an amount of 50 to 150 parts by weight based on 100 parts by weight of the adhesive component (A). It is preferable to contain 50 to 150 parts by weight of crystalline silica.
Amorphous silica has excellent properties to incorporate the ink into the layer of adhesive formed by the cold seal adhesive, thereby improving the color development of the ink and the amphoteric that may be present in the ink and the adhesive. It is thought that it works effectively on the expression of ionic interaction with the polymer.

Furthermore, the cold seal adhesive of the present invention may comprise an auxiliary.
Here, the "auxiliary agent" is an auxiliary agent usually used in a cold seal adhesive, and is not particularly limited as long as it does not adversely affect the cold seal adhesive of the present invention. Usually, the "auxiliary agent" refers to a substance that imparts blocking resistance, printability, abrasion resistance, adhesion to paper, and the like. Examples of the auxiliary agent include water-soluble resins such as polyvinyl alcohol (PVA), starch, casein, polystyrene maleic acid, carboxymethyl cellulose, synthetic rubber, acrylic emulsion, and polyolefin-based emulsions.

The cold seal adhesive of the present invention is in the form of an aqueous emulsion, and contains an adhesive component (A), an acetoacetylated polyvinyl alcohol (B), and an amphoteric polymer (C) contained as necessary, in an aqueous solvent. It has a form dispersed inside. In order to maintain this form and develop appropriate adhesive properties, it can be produced by appropriately adding an aqueous solvent, stored, and used.

Further, the cold seal adhesive of the present invention may include a cationic polymer.
In the cold seal adhesive of the present invention, a small amount of a cationic polymer can be further added to the cold seal adhesive as needed and according to desired characteristics. Thereby, when the substrate sheet coated with the cold seal adhesive of the present invention to form an adhesive layer is used for an ink jet printer, the water resistance and non-transfer strength of the aqueous dye can be easily increased. And the water resistance and non-transferability of the print can be ensured.

As used herein, the term “cationic polymer” refers to a polymer having a positive charge, and as long as addition of a small amount does not adversely affect the adhesive properties and the like of the cold seal adhesive, a cationic polymer is used. It is not particularly limited.
Examples of the cationic polymer include polydimethylamine ammonia epichlorohydrin, polydimethylamine ethylenediamine epichlorohydrin and the like (see JP-A-10-52985), diallyldimethylammonium chloride, polyamide-epoxy resin, polyamide-urea resin, aldehyde-based resin And melanin-based resins (see JP-A-9-71758). In particular, polydimethylamine ammonia epichlorohydrin, diallyldimethyl ammonia chloride and the like can be preferably used.
These cationic polymers can be used alone or in combination.

In the cold seal adhesive of the present invention, various additives can be blended.
Here, as the "additive", an additive usually used as needed in the cold seal adhesive can be used. As additives, for example, lubricants, printability improvers, antioxidants, UV absorbers, conductive agents, fluorescent paints, coloring dyes, stabilizers, defoamers, fungicides, antibacterial agents, thickeners, and Humectants and the like can be exemplified.
Furthermore, in the present invention, in order to enhance the blocking resistance of the cold seal adhesive, a polyethylene dispersion as an additive and / or a tackifier such as a rosin-based tackifier may be added to impart tackiness properties. .
These additives can be used singly or in combination, and can be appropriately selected and used according to the required properties, and provide a cold seal adhesive excellent in printability, stability, and mold resistance. Can be.

The cold seal adhesive of the present invention is suitable as a cold seal adhesive for applying an adhesive to a base sheet to form an adhesive layer and applying pressure to obtain an information carrier.
Accordingly, the present invention provides a base sheet having an adhesive layer formed by applying the above cold seal adhesive.

According to the present invention, in order to further obtain an information carrier, the cold sheet adhesive described above is applied to a base sheet to provide an adhesive portion in which an adhesive layer is formed.
Here, the “adhesion site” refers to a site where a cold seal adhesive is applied to form an adhesive layer, but is not yet bonded by applying pressure.
Therefore, the present invention further provides an information carrier having the above-mentioned adhesion site. As such an information carrier, a confidential postcard is particularly preferable.

When the cold seal adhesive of the present invention is applied to a base sheet (for example, high-quality paper) to form an adhesive layer, and then the base sheet is further processed to produce, for example, a confidential postcard as an information carrier. The form of various confidential postcards can be appropriately selected depending on the information and use of the confidential postcard, and the form is not particularly limited. As a form of such a confidential postcard, for example, an adhesive layer is formed only on one surface of the base sheet, and the base sheet is folded in two and a two-sided spread postcard is formed. An adhesive layer is formed only on one side, the base sheet is folded in three by so-called Z-fold, and a pair of opposed two sides is pressure-bonded in the form of a six-sided postcard. A form such as a six-sided postcard in which a layer is formed, the base sheet is tri-folded by Z-fold, and two sets of two opposing faces are pressure-bonded.

In addition, as a method of applying the cold seal adhesive of the present invention, a method usually used as a method of applying a cold seal adhesive can be used. The application method is not particularly limited as long as the cold seal adhesive of the present invention can be applied. Examples of such a coating method include a roll coater, a bar coater, a blade coater, an air knife coater, a rod blade coater, and a gravure roll coater.

Further, in the present specification, “crimping” is a method conventionally used for bonding a cold seal adhesive, and the two surfaces on which the cold seal adhesive is applied to form an adhesive layer are bonded together. Applying pressure and, if necessary, heat as necessary to overlap the two surfaces so as to make contact with each other.
Therefore, the term "pressure bonding" also means that the above-mentioned base sheet is bonded integrally by applying pressure to the bonding site.

Hereinafter, the present invention will be described specifically and in detail with reference to examples and comparative examples. However, these examples are only one embodiment of the present invention, and the present invention is not limited by these examples.
In the description of the examples, unless otherwise specified, the parts that do not consider the solvent are based on parts by weight and% by weight.

Example 1
4 parts by weight of (d1) acrylic acid and 96 parts by weight of (e1) dimethylaminoethyl methyl methacrylate chloride ((CH ₂ ＣC (CH ₃ ) COOCH ₂ CH ₂ N (CH ₃ ) ₃ ) ⁺ Cl ⁻ ] To 900 parts by weight of distilled water, 1 part by weight of 2,2-azobis (2-diaminopropane) hydrochloride was added with stirring, and then heated to 80 ° C. to react for 3 hours. (C1) The molecule was synthesized.

On the other hand, 90 parts by weight of the above-mentioned (c1) amphoteric polymer, based on 100 parts by weight of (a1) methyl methacrylate-modified natural rubber latex obtained by copolymerizing natural rubber latex with methyl methacrylate by a conventional method, 30 parts by weight of (b1) acetoacetylated polyvinyl alcohol (Gosefimer Z210 (trade name) manufactured by Nippon Synthetic Chemical Industry: degree of polymerization 1,100, degree of saponification 95 to 97 mol% (approximately 5 mol% is acetoacetylated)), 170 parts by weight of (f1) amorphous silica (average particle diameter is 2.0 to 2.5 μm, oil absorption is 250 ml / 100 g, specific surface area is 300 m ² / g) and a fine particle filler composed of 30 parts by weight of starch were blended to obtain a cold seal adhesive of Example 1.

The dispersion stability of the cold seal adhesive is measured by the grit value of the adhesive (whether or not aggregates are generated when the cold seal adhesive is blended), the time-dependent change in the viscosity of the cold seal adhesive, and the visual observation of the cold seal adhesive. It was evaluated by observation. The viscosity was measured using a B-type viscometer (30 ° C.). No occurrence of grit was observed, there was substantially no increase in viscosity, and those in which aggregates could not be visually observed were evaluated as ○ .Even if grit was not observed and aggregates could not be visually observed, the viscosity was increased. The increase was indicated by Δ, and the formation of grit was observed, the viscosity increased, and the gel was formed, and x was indicated. The results are shown in Table 1.

Evaluation of Cold Seal Adhesive (1) Preparation of Test Sheet The cold seal adhesive was applied to one surface of a base sheet made of high quality paper (130 g / m ² ) so that the coated amount after drying was 10 g / m ^2. Coating and drying were performed to obtain a substrate sheet having an adhesive layer formed thereon (hereinafter also referred to as “adhesive coated sheet”). After printing using black ink, red ink, blue ink and green ink manufactured by Cytex Co., Ltd. on the adhesive layer of the adhesive coated sheet using an ink jet printer, the temperature of 105 ° C. An adhesive-coated sheet (hereinafter referred to as “test sheet”) dried in a dryer for 1 minute was obtained.

(2) Evaluation of water resistance of ink-jet recorded prints The water resistance of ink-jet recorded prints was evaluated by immersing the printed portion of the test sheet in water for 3 minutes, then bleeding the print, and then printing the aqueous dye into water. The test was performed by visually observing whether or not the test paper was eluted, and the overall appearance of printing after the test paper was taken out of the water. The case where the printing of the test sheet did not change at all as compared to before immersion in water was evaluated as ○, the case where the change was slight but not conspicuous was evaluated as Δ, and the case where even a slight change was observed was evaluated as x. The results are shown in Table 1. In all the examples and comparative examples, there was no difference in the result due to the difference in the color type.

(3) Evaluation of non-transfer property of ink-jet recorded print The non-transfer property of ink-jet recorded print was evaluated by folding a test sheet into two pieces and measuring 10,000,000 N / m at a temperature of 20 ° C and a humidity of 60%. Pressing was performed at a surface pressure of ² , and when the film was peeled again after a lapse of 30 minutes, the presence or absence of transfer of the print was visually observed. When the test sheet did not transfer at all, the test was rated as 印字, when the transfer was slight but inconspicuous, and Δ when the transfer was slightly noticeable. The results are shown in Table 1.

(4) Evaluation of the abrasion resistance of the adhesive layer The evaluation of the abrasion resistance of the adhesive layer is based on the abrasion resistance (dry) when the adhesive-coated sheet is not in contact with water and the abrasion resistance when the adhesive coating sheet is in contact with water. Evaluation was made by measuring two types of abrasion resistance (wetness).
The abrasion resistance (dry) was evaluated using a Gakushin-type abrasion resistance tester, using a weight of 1,100 g, and abrading the surface of the adhesive-coated sheet 200 times. Was carried out by visually observing the state of the surface. When the surface of the adhesive-coated sheet is hardly scraped, ○ indicates that shavings are generated, and when the surface is shaved less than 10%, Δ indicates that a large amount of shavings is generated and the surface shaving is 10% or more. The case was marked as x. The results are shown in Table 1.

The abrasion resistance (wet) was evaluated by dropping one drop of water on the surface of the adhesive-coated sheet, and using a gakushin-type abrasion-fastness tester with a 500 g weight using the adhesive-coated sheet. After the surface was abraded 20 times, the state of the surface of the adhesive-coated sheet was visually observed. The case where the shaving of the surface was less than 10% was evaluated as ○, the case where it was 10% or more, and less than 50% as Δ, and the case where it was 50% or more as x. The results are shown in Table 1.

Example 2
Example 2 was repeated in the same manner as in Example 1 except that (b1) acetoacetylated polyvinyl alcohol was changed to 20 parts by weight based on 100 parts by weight of (a1) methyl methacrylate-modified natural rubber latex. Was obtained as a cold seal adhesive.
In a manner similar to that described in Example 1, the dispersion stability of the cold seal adhesive of Example 2, the water resistance and non-transferability of the ink jet recorded print, and the abrasion resistance of the adhesive layer (dry and Wet) was evaluated. The results are shown in Table 1.

Example 3
Example 2 was repeated in the same manner as in Example 1 except that (b1) acetoacetylated polyvinyl alcohol was changed to 10 parts by weight based on 100 parts by weight of (a1) methyl methacrylate-modified natural rubber latex. Was obtained as a cold seal adhesive.
In a manner similar to that described in Example 1, the dispersion stability of the cold seal adhesive of Example 3, the water resistance and non-transferability of ink jet recorded prints, and the abrasion resistance of the adhesive layer (dry and dry) Wet) was evaluated. The results are shown in Table 1.

Example 4
In Example 1, (b1) acetoacetylated polyvinyl alcohol was replaced with (b2) acetoacetylated polyvinyl alcohol (Gosefimer Z100 (trade name) manufactured by Nippon Synthetic Chemical Industry: polymerization degree 500, saponification degree 98.5 mol) % (About 5 mol% of the saponified portion is acetoacetylated)), and the cold seal adhesive of Example 4 was obtained in the same manner as in Example 1.
In a manner similar to that described in Example 1, the dispersion stability of the cold seal adhesive of Example 4, water resistance and non-transferability of ink jet recorded prints, and abrasion resistance of the adhesive layer (dry and Wet) was evaluated. The results are shown in Table 1.

Example 5
In Example 1, (b1) acetoacetylated polyvinyl alcohol was replaced with (b3) acetoacetylated polyvinyl alcohol (Gosefimer Z200 (trade name) manufactured by Nippon Synthetic Chemical Industry: polymerization degree 1,100, saponification degree 99 mol) % (About 5 mol% of the saponified portion is acetoacetylated)), and the cold seal adhesive of Example 5 was obtained in the same manner as in Example 1.
In a manner similar to that described in Example 1, the dispersion stability of the cold seal adhesive of Example 5, the water resistance and non-transferability of ink jet recorded prints, and the abrasion resistance of the adhesive layer (dry and Wet) was evaluated. The results are shown in Table 1.

Example 6
In Example 1, (b1) acetoacetylated polyvinyl alcohol was replaced with (b4) acetoacetylated polyvinyl alcohol (Gosefimer Z320 (trade name) manufactured by Nippon Synthetic Chemical Industry: polymerization degree 1,600, saponification degree 92 to A cold seal adhesive of Example 5 was obtained in the same manner as in Example 1 except that 94 mol% (about 5 mol% of the saponified portion was acetoacetylated).
In a manner similar to that described in Example 1, the dispersion stability of the cold seal adhesive of Example 5, the water resistance and non-transferability of ink jet recorded prints, and the abrasion resistance of the adhesive layer (dry and Wet) was evaluated. The results are shown in Table 1.

Comparative Example 1
A cold seal adhesive of Comparative Example 1 was obtained in the same manner as in Example 1 except that (c1) the amphoteric polymer was not used at all.
In the same manner as described in Example 1, the dispersion stability of the cold seal adhesive of Comparative Example 1, the water resistance and non-transferability of the ink jet recorded print, and the abrasion resistance of the adhesive layer (dry and Wet) was evaluated. The results are shown in Table 2.

Comparative Example 2
In Example 1, 10 parts by weight of a cationic polymer (polydimethylamine ammonia epichlorohydrin) was used instead of 90 parts by weight of the (c1) amphoteric polymer, and 100 parts by weight of (f1) amorphous silica was used. Then, a cold seal adhesive of Comparative Example 2 was obtained in the same manner as in Example 1 except that 50 parts by weight of (f1) was used.
In the same manner as described in Example 1, the dispersion stability of the cold seal adhesive of Comparative Example 2, the water resistance and non-transferability of the ink jet recorded print, and the abrasion resistance of the adhesive layer (dry and Wet) was evaluated. The results are shown in Table 2.

Comparative Example 3
Example 1 A method described in Example 1 except that (b1) partially saponified polyvinyl alcohol (polymerization degree 300 to 700 and saponification degree 87 to 89 mol%) was used instead of acetoacetylated polyvinyl alcohol. In the same manner as in the above, a cold seal adhesive of Comparative Example 3 was obtained.
In a manner similar to that described in Example 1, the dispersion stability of the cold seal adhesive of Comparative Example 3, the water resistance and non-transferability of the ink jet recorded print, and the abrasion resistance of the adhesive layer (dry and dry) Wet) was evaluated. The results are shown in Table 2.

ａ）−は、評価不能であったことを示す。

a)-indicates that evaluation was not possible.

Preferred embodiments of the present invention are described below.
1. Adhesive component (A) comprising at least one selected from natural rubber latex, modified natural rubber latex, and synthetic rubber latex, acetoacetylated polyvinyl alcohol (B), and amphoteric polymer (C) A cold seal adhesive, characterized in that:
2. The amphoteric polymer (C) is obtained by copolymerizing a monomer mixture containing an anionic monomer (D) and a cationic monomer (E) as essential components,
A monomer having a carboxyl group and an ethylenic double bond between carbon atoms and / or a monomer having a carboxylate group and a double bond between ethylenic carbon atoms and / or a sulfone A monomer having an acid group and an ethylenic carbon double bond and / or a monomer having a sulfonate group and an ethylenic carbon double bond and / or a phosphoric acid group and an ethylenic carbon double A monomer having a bond and / or a monomer having a phosphate group and an ethylenic carbon-carbon double bond,
The cationic monomer (E) is a monomer having an amino group and an ethylenic carbon-carbon double bond and / or a monomer having an ammonium base and an ethylenic carbon-carbon double bond and / or a pyridyl group 2. The cold seal adhesive according to claim 1, comprising a monomer having a double bond between ethylenic carbon atoms and / or a monomer having a double bond between a pyridinium base and an ethylenic carbon atom. .
3. 3. The cold seal adhesive according to the above item 1 or 2, further comprising a cationic polymer.
4. 4. The cold seal adhesive according to any one of the above items 1 to 3, further comprising amorphous silica.
5. The cold seal adhesive according to any one of the above items 1 to 4, for inkjet recording.

Claims (4)

Adhesive component (A) comprising at least one selected from natural rubber latex, modified natural rubber latex, and synthetic rubber latex, acetoacetylated polyvinyl alcohol (B), and amphoteric polymer (C) A base sheet having an adhesive layer formed by applying a cold seal adhesive,
The amphoteric polymer (C) is obtained by copolymerizing a monomer mixture containing an anionic monomer (D) and a cationic monomer (E) as essential components,
A monomer having a carboxyl group and an ethylenic double bond between carbon atoms and / or a monomer having a carboxylate group and a double bond between ethylenic carbon atoms and / or a sulfone A monomer having an acid group and an ethylenic carbon double bond and / or a monomer having a sulfonate group and an ethylenic carbon double bond and / or a phosphoric acid group and an ethylenic carbon double A monomer having a bond and / or a monomer having a phosphate group and an ethylenic carbon-carbon double bond,
The cationic monomer (E) is a monomer having an amino group and an ethylenic carbon-carbon double bond and / or a monomer having an ammonium base and an ethylenic carbon-carbon double bond and / or a pyridyl group And a monomer having a double bond between ethylenic carbon atoms and / or a monomer having a double bond between a pyridinium base and an ethylenic carbon atom. The base sheet according to claim 1, wherein the cold seal adhesive further comprises a cationic polymer. The substrate sheet according to claim 1 or 2 for inkjet recording. The base sheet according to any one of claims 1 to 3, which is used as a confidential postcard.