JP2021042265A - Removable aqueous pressure-sensitive adhesive and adhesive sheet - Google Patents

Abstract

To provide a removable aqueous pressure-sensitive adhesive that gives an adhesive sheet achieving both removability after used at a temperature as high as 100°C or more (high-temperature removability) and durability and suppressing contamination in high-speed peeling.SOLUTION: An aqueous pressure-sensitive adhesive is provided, which comprises a water-dispersible polymer (A) comprising a structural unit derived from an ethylenically unsaturated compound (a1) represented by formula (1): CH2=C(R1)COO(R4O)nPOOR2OR3, a structural unit derived from an ethylenically unsaturated compound (a2) having a carboxyl group, and a structural unit derived from an ethylenically unsaturated compound (a3) having an alkyl group having 4 to 24 carbon atoms, and having no aromatic rings. In formula (1), n represents an integer of 1 to 4; R1 represent H or a methyl group; R2 and R3 represent H or alkyl group which may be substituted with a hydroxyl group and/or an oxyalkylene group; R4 represents an alkylene group having 2 to 4 carbon atoms; and R2 and R3 are not allowed to be simultaneously H.SELECTED DRAWING: None

Description

The present invention relates to a removable water-based pressure-sensitive adhesive and an adhesive sheet using the same.

Pressure-sensitive adhesives are widely used in industrial fields such as packaging, construction, building materials, automobiles, and electronic parts, as well as in general households. The most common laminated structure of the adhesive sheet is "support (also known as base sheet) / adhesive layer / release sheet" (single-sided pressure-sensitive adhesive sheet) or "release sheet / adhesive layer / support (release sheet / adhesive layer / support). Another name: base sheet) / adhesive layer / release sheet ”(double-sided pressure-sensitive adhesive sheet). At the time of use, the release sheet is peeled off and the adhesive layer is attached to the adherend. Adhesive sheets (hereinafter, pressure-sensitive adhesive sheets are abbreviated as adhesive sheets) are used for various purposes and require various adhesive strengths.

As a component of the pressure-sensitive adhesive, an elastic body such as natural rubber or synthetic rubber or an acrylic resin is used. Adhesive labels, adhesive sheets, adhesive tapes, etc., which are formed by forming a layer of these pressure-sensitive adhesives on the surface of a support such as paper, plastic film, cloth, or metal plate, are applied to the surface of the adherend at room temperature at a pressure equivalent to finger pressure. Since it can be easily adhered, it is widely used in various fields in various fields. It goes without saying that such adhesive labels are required not to easily fall off when attached to the adherend, but they can be easily peeled off after a certain period of time after being attached to the adherend. Is often required.

For example, adhesive labels attached to various containers and adhesive tapes used for fixing parts in electrical equipment may be peeled off for recycling and reuse of adherends. Further, for example, an adhesive tape such as a masking tape attached to an adherend for painting or forming a sealing material is peeled off from the adherend after the coating film or the sealing material is dried and formed. .. Further, for example, an adhesive sheet such as a surface protective film attached to an adherend at the manufacturing stage of a product such as a display may be peeled off when the product is used.
In such a case, the adhesive strength varies greatly depending on the material of the adherend, changes over time after sticking to the adherend, changes in the environment such as temperature and humidity, etc., but changes in the adhesive strength due to these various factors It is very difficult to control. In particular, if the adhesive strength between the adhesive label or the like and the adherend is too high, the pressure-sensitive adhesive remains on the adherend when trying to peel off, or the support is made of paper. Is destroyed (also known as substrate fracture), so-called paper tearing occurs, making re-peeling difficult. Further, if the adhesive force between the adhesive label or the like and the adherend is too low, the adhesive label or the like can be easily peeled off, but the adhesive label or the like cannot be sufficiently adhered to the adherend, and the purpose originally expected for the adhesive label or the like can be achieved. It will be difficult.

In recent years, water-based pressure-sensitive adhesives have begun to increase in consideration of the protection of the global environment and the working environment. Among them, water-based pressure-sensitive adhesives containing an acrylic resin having excellent adhesiveness and weather resistance as a main component have become widespread. For example, by blending a diisocyanate compound, a glycidyl compound, or the like as a cross-linking agent in the resin constituting the pressure-sensitive adhesive, the cohesive force of the adhesive layer is enhanced and the pressure-sensitive adhesive is transferred onto the adherend (also known as glue). The rest) is being reduced. The pressure-sensitive adhesive containing a cross-linking agent has increased cohesive force and improved temperature sensitivity, but as the cohesive force increases, the adhesiveness to the adherend becomes poor and the adhesive force decreases. Especially for polyolefins, a significant decrease in adhesive force and deterioration of curved surface adhesiveness are observed, and further decrease in cohesive force in high temperature and high humidity environment and decrease in adhesive force at low temperature are likely to occur. It causes deterioration of performance. As described above, in order to satisfy the removability, the adhesive force to the adherend had to be sacrificed to some extent.

In such an environment, various attempts have been made to satisfy the various characteristics described above. For example, in Patent Document 1, (a1) 50 to 99.89% by weight of a (meth) acrylic acid alkyl ester containing an alkyl group having 4 to 12 carbon atoms, and (a2) an unsaturated monomer containing a carboxyl group 0.1 to 0.1. Anion is a monomer mixture containing 10% by weight, (a3) 0.01 to 10% by weight of unsaturated monomer containing a carbonyl group, and (a4) 0 to 49.89% by weight of other unsaturated compounds. An emulsion of an acrylic resin having a glass transition temperature of more than -50 ° C and -25 ° C or less and having a gel content of less than 70% by weight, obtained by emulsifying and polymerizing in the presence of a type-reactive surfactant, [B]. A removable water-based pressure-sensitive adhesive comprising a hydrazine-based compound and a [C] phosphoric acid ester-based compound is disclosed.

For example, the pressure-sensitive type of the resin aqueous dispersion is characterized by containing 0.1 to 10 parts by mass of a surfactant (A) having a phosphoric acid group with respect to 100 parts by mass of the resin. It is known to produce adhesive labels, films and tapes that can be peeled off from a support by using an adhesive (see Patent Document 2).

For example, 0.5 to 70 parts by mass of a phosphorus-containing monomer (A) having a specific structure having a phosphoric acid ester group using a six-membered ring aromatic hydrocarbon as a substituent and the phosphorus-containing monomer (A). ), By subjecting 100 parts by mass of the total monomer composed of the monomer (B) selected from the group consisting of aromatic vinyl-based monomers and the like to the above-mentioned problem. A copolymer that solves the above problems is obtained, and by using this copolymer as a component, a resin-based aqueous dispersion and a backing agent for fiber treatment that are excellent in various properties such as flame retardancy, workability, and imparting a good texture. Is known to be obtained (see Patent Document 3).

For example, a pressure-sensitive adhesive comprising a (meth) acrylic acid ester-based polymer containing a repeating unit composed of a (meth) acrylic acid ester having a phosphoric acid ester group, and the adhesive on at least one side of a support. A pressure-sensitive adhesive laminate having an excellent flame retardancy and transparency, which is characterized by having a layer, is known (see Patent Document 4).

Japanese Unexamined Patent Publication No. 2006-045411 Japanese Unexamined Patent Publication No. 2002-309223 Japanese Unexamined Patent Publication No. 2009-286849 Japanese Unexamined Patent Publication No. 2010-150430

However, although the water-based pressure-sensitive adhesive described in Patent Document 1 has a certain level of high-temperature performance, it is difficult to achieve both removability when used in a high-temperature atmosphere and durability at high temperatures. It was. Further, since the adhesiveness between the pressure-sensitive adhesive layer and the base material is insufficient, there is a problem that contamination (glue residue) occurs when the adhesive sheet is peeled off at high speed.

Further, the water-based pressure-sensitive adhesive described in Patent Document 2 exhibits good adhesiveness when a phosphoric acid-based surfactant is used as a polymerization emulsifier and the adherend is a plastic, but the adherend is adhered. If the body is made of metal or cardboard, it will not be possible to obtain practical adhesive strength. In addition, adherend contamination (cloudiness, adhesive residue) derived from a phosphoric acid-based surfactant may be observed.

Further, the aqueous pressure-sensitive adhesive described in Patent Document 3 has improved flame retardancy by using an aqueous resin dispersion copolymerized with an ethylenically unsaturated compound having an aromatic ring-containing phosphoric acid ester. In addition, the adhesive strength is also increased, so the adhesive label attached is inferior in removability, and if the adhesive remains on the adherend or the support is paper, the base material may break (paper tear). is there.

Further, the water-based pressure-sensitive adhesive described in Patent Document 4 is flame-retardant as described above when an aqueous resin dispersion obtained by copolymerizing an ethylenically unsaturated compound having an aromatic ring-containing phosphoric acid ester is used. However, due to the increase in adhesive strength, adherend contamination (cloudiness, adhesive residue) and substrate breakage in the paper substrate may occur. When an aqueous dispersible polymer copolymerized with an ethylenically unsaturated compound having an alkyl group having 1 to 8 carbon atoms is used, the polarity of the phosphoric acid portion is too high, so that the adhesive strength also increases and the adhesion is also increased. Body contamination (cloudiness, adhesive residue) and substrate breakage in the paper substrate are likely to occur, and the removability is inferior.

The problem to be solved by the present invention is to achieve both removability after being used at a high temperature of 100 ° C. or higher (hereinafter, high temperature removability) and durability, and adhesion that suppresses contamination in high-speed peeling. It is to provide a removable water-based pressure-sensitive adhesive that can obtain a sheet.

As a result of diligent studies to solve the above problems, the present inventors have found that the above object can be achieved by the removable water-based pressure-sensitive adhesive shown below, and have completed the present invention.

That is, in the embodiment of the present invention, a structural unit derived from the ethylenically unsaturated compound (a1) represented by the following general formula (1), a structural unit derived from the ethylenically unsaturated compound (a2) having a carboxyl group, An aqueous pressure-sensitive formula containing a water-dispersible polymer (A) having no aromatic ring and containing a structural unit derived from an ethylenically unsaturated compound (a3) having an alkyl group having 4 to 24 carbon atoms. It is an adhesive.

(In the formula, n is an integer of 1 to 4. R ₁ is a hydrogen atom or a methyl group. R ₂ and R ₃ are independently hydrogen atoms or hydroxyl groups and / or oxyalkylene groups, respectively. It is an alkyl group that may be substituted. R ₄ is an alkylene group having 2 to 4 carbon atoms. R ₂ and R ₃ are not hydrogen atoms at the same time.)

Further, in the embodiment of the present invention _{, the above-mentioned aqueous feeling in which the above-mentioned R 2} and R ₃ are independently hydrogen atoms or alkyl groups or groups represented by any of the following general formulas (2) to (4). It is a pressure adhesive.

(In the formula, m and l are integers of 1 to 20. R ₅ , R ₈ and R ₁₀ are alkyl groups. R ₆ and R ₉ are alkylene groups having 2 to 4 carbon atoms. R ₇ is an alkylidine group.)

Further, in the embodiment of the present invention, as the structural unit of the polymer (A), an ethylenically unsaturated compound having a structural unit derived from the ethylenically unsaturated compound (a4) having a hydroxyl group and / or a carbonyl group ( The water-based pressure-sensitive adhesive is characterized by containing a structural unit derived from a5). (However, the compound (a4) excludes the compound (a1), and the compound (a5) excludes the compound (a2).)

Further, in the embodiment of the present invention, in 100% by mass of the structural unit of the polymer (A),
The above compound (a1) 0.1 to 10% by mass,
The compound (a2) 0.1 to 10% by mass, and the compound (a3) 80 to 99.8% by mass.
The above-mentioned water-based pressure-sensitive adhesive containing.

Further, in the embodiment of the present invention, in 100% by mass of the polymer (A),
The above compound (a1) 0.1 to 10% by mass,
The above compound (a2) 0.1 to 10% by mass,
The above compound (a3) 65-99.78% by mass,
The compound (a4) 0 to 10% by mass, and the compound (a5) 0 to 5% by mass,
The above-mentioned water-based pressure-sensitive adhesive containing. (However, the total of the above compound (a4) and the above compound (a5) does not become 0% by mass.)

Further, an embodiment of the present invention is the water-based pressure-sensitive adhesive characterized in that the glass transition temperature of the polymer (A) is in the range of −80 to −10 ° C.

Further, an embodiment of the present invention is the water-based pressure-sensitive adhesive which further contains a structural unit derived from the reactive surfactant (B) as a structural unit of the polymer (A).

Further, in the embodiment of the present invention, the reactive surfactant (B) is the aqueous pressure-sensitive adhesive containing an anionic reactive surfactant and / or a nonionic reactive surfactant.

Further, an embodiment of the present invention is the water-based pressure-sensitive adhesive further containing a reactive compound (C) capable of reacting with the polymer (A). (However, the compound (C) excludes the reactive surfactant (B).)

Further, in the embodiment of the present invention, the polymer (A) has a hydroxyl group and / or a carbonyl group, and the reactive compound (C) has a hydroxyl group and / or a hydroxyl group in the polymer (A). The above-mentioned water-based pressure-sensitive adhesive that can react with a carbonyl group.

Further, an embodiment of the present invention is an adhesive sheet including a base material and an adhesive layer formed from the above-mentioned water-based pressure-sensitive adhesive.

The present invention contains a water-dispersible polymer having a phosphoric acid ester and no aromatic ring, so that it has good adhesiveness to various adherends, which could not be realized by a conventional pressure-sensitive adhesive. It has become possible to manufacture re-peelable adhesive labels and the like having re-peelability. In addition, the obtained adhesive sheet has improved cohesive force of the adhesive layer, so that both high-temperature removability and durability can be achieved at the same time. Further, since the phosphoric acid ester moiety in the water-dispersible polymer is oriented at the interface between the adhesive layer and the adherend, contamination in high-speed peeling can be suppressed.

Hereinafter, embodiments of the present invention will be described.
In the present specification, an aqueous dispersible polymer (A) having no aromatic ring, a reactive compound (B) capable of reacting with the polymer (A), and an ethylenically unsaturated represented by the following general formula (1). The compound (a1), the ethylenically unsaturated compound having a carboxyl group (a2), the ethylenically unsaturated compound having an alkyl group having 4 to 24 carbon atoms (a3), and the ethylenically unsaturated compound having a hydroxyl group (a4) are: An ethylenically unsaturated compound (a5) having a carbonyl group, an ethylenically unsaturated compound (a7) having a phosphoric acid group, and another ethylenically unsaturated compound (a6) are mixed with a polymer (A) and a reactive compound (a6), respectively. B), compound (a1), compound (a2), compound (a3), compound (a4), compound (a5), compound (a6) and compound (a7) may be abbreviated.

In addition, when it is described as "(meth) acrylic", "(meth) acryloyl", "(meth) acrylic acid", "(meth) acrylate", "(meth) acryloyloxy", and "(meth) allyl". Unless otherwise stated, "acrylic or methacrylic", "acryloyl or methacrylic acid", "acrylic acid or methacrylic acid", "acrylate or methacrylate", "acryloyloxy or methacryloyloxy", and "allyl or methacrylic acid", respectively. ".
Hereinafter, each component constituting the aqueous dispersion resin (A) will be specifically described.

<Water-dispersible polymer having no aromatic ring (A)>
The water-dispersible polymer (A) having no aromatic ring is an ethylenically unsaturated compound (a1) unit represented by the general formula (1) as a monomer constituting the copolymer, and has a carboxyl group. It is a resin containing an unsaturated compound (a2) unit and an ethylenically unsaturated compound (a3) unit having an alkyl group having 4 to 24 carbon atoms, and is a resin obtained by emulsifying and polymerizing a mixture of these monomers.

<< Ethylene unsaturated compound (a1) represented by the general formula (1) >>
Compound (a1) is a compound having a phosphoric acid ester structure and an ethylenically unsaturated double bond group, and is a compound containing one or more organic phosphoric acid ester residues. The phosphoric acid ester structure is a structure in which _{all or part of the three hydrogens of phosphoric acid (O = P (OH) 3} ) are replaced with organic groups, and the number of substitutions is 1, 2, or 3. Those are called phosphoric acid monoester, phosphoric acid diester, and phosphoric acid triester in order, and phosphoric acid ester is a general term for them. Specifically, the compound (a1) essentially contains at least one ethylenically unsaturated double bond group, and one or two _{organic groups (R 2} or R _{3), which are other substituents, are replaced.} It is also a phosphoric acid diester or a phosphoric acid triester.

Of the general formula (1), _{it is preferable that R 2} and R ₃ are independently hydrogen atoms or alkyl groups or groups represented by any of the general formulas (2) to (4).

_{R 4} in the general formula (1) _{, R 6} in the general formula (2), _{and R 9} in the general formula (4) are alkylene groups having 2 to 4 carbon atoms. Examples of the alkylene group having 2 to 4 carbon atoms include an ethylene group, a propylene group, an isopropylene group, a trimethylene group, a butylene group, an isobutylene group and a 2-methylpropylene group.

_{When R 2} and R ₃ in the general formula (1) are alkyl groups, linear or branched alkyl groups having 8 to 24 carbon atoms are preferable, and such alkyl groups include, for example, 2-. Ethylhexyl group, n-octyl group (also known as capryl group), isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, undecyl group, dodecyl group (also known as lauryl group), tridecyl group, tetradecyl group (also known as myristyl group) Group), pentadecyl group, hexadecyl group (also known as cetyl group), heptadecyl group, octadecyl group (also known as stearyl group), 16-methyl-heptadecyl group (also known as isostearyl group), nonadesyl group, icosyl group (also known as araquil). Groups), docosyl groups (also known as behenyl groups), tetracosyl groups (also known as lignoceryl groups) and the like.

_{When any one of R 2} and R ₃ of the general formula (1) is the general formula (2), the general formula (3) or the general formula (4), R ₅ , R ₈ and R ₁₀ are It is preferably a linear or branched alkyl group having 8 to 24 carbon atoms.

_{Further, when any one of R 2} and R ₃ of the general formula (1) is independently the general formula (3) or the general formula (4), R ₇ has 3 to 8 carbon atoms. A linear or branched alkylidiin group is preferable, and examples of such an alkyl group include a propyridin group, a butyridin group, an isobutyridin group, a 2-ethylpropyridin group, a 2,2-dimethylpropyridin group, and 2 -Methyl-2-ethylpropyridin group, 2-methyl-2-butylpropyridin group, 2-ethyl-2-butylpropyridin group, pentylidiin group, 2-methylbutyridin group, 3-methylbutyridiin Examples thereof include a group, a 1,2-dimethylpropyridin group, a 2,2-dimethylpropyridin group and the like.

As described above, when the compound (a1) has the structure of the general formula (1) as described above, the affinity with other compounds constituting the water-dispersible polymer (A) is low, and therefore the adhesive layer. Inside, it is oriented at the interface between the adhesive layer and the adherend, and the surface polarity is changed. Therefore, even if it is attached to a harsh atmosphere of high temperature and high humidity and exposed for a long period of time, the cohesive force of the adhesive layer is not reduced, and the adhesive layer and the adherend are excessively separated while having good adhesive force. Since it does not adhere to each other, it can be easily peeled off. Further, when the adherend is peeled off, the surface of the adherend is not contaminated with fogging or adhesive residue, and the base material such as the paper base material is not broken, so that good re-peelability can be exhibited. Furthermore, since it does not have an aromatic ring, it can be made excellent in various performances such as imparting a good texture.

The ethylenically unsaturated compound (a1) represented by the general formula (1) is characterized by containing an ethylenically unsaturated group and a phosphoric acid ester moiety, and is typically produced by the following three known methods. can do.
[First method]
An alkyl alcohol (a1-2) and / or a polyoxyethylene alkyl ether (a1-3) is added to a phosphoric acid derivative (a1-1) and an ethylenically unsaturated compound (a4) having a hydroxyl group, which will be described later. A method for producing this mixture by subjecting it to a dehydration condensation reaction.
[Second method]
Alkyl alcohol (a1-2) and / or polyoxyethylene alkyl ether (a1-3) is added to an ethylenically unsaturated compound (a7) having a phosphoric acid group, and this mixture is dehydrated and condensed to produce. how to.
[Third method]
A cyclic ether (a1-4) having an alkyl group and / or a cyclic ether (a1-5) having a polyoxyalkylene alkyl ether group is added to the ethylenically unsaturated compound (a7) having a phosphoric acid group. A method for producing this mixture by subjecting it to a ring-opening addition reaction.

In the first method, the reaction products with the phosphoric acid derivative (a1-1), the compound (a4) and the alkyl alcohol (a1-2) are such that R ₂ and R ₃ of the general formula (1) are independent of each other. , Hydrogen atom, alkyl group. R ₂ and R ₃ are not hydrogen atoms at the same time. Further, the reaction products of the phosphoric acid derivative (a1-1), the compound (a4) and the polyoxyethylene alkyl ether (a1-3) _{are independent of R 2} and R ₃ of the general formula (1), respectively. In addition, it is a hydrogen atom, an oxyalkyl group represented by the general formula (2). R ₂ and R ₃ are not hydrogen atoms at the same time. However, in the formula, m is an integer of 1 to 20. R ₆ is an alkylene group having 2 to 4 carbon atoms independently. R ₅ is an alkyl group.

In the second method, the reaction product of the compound (a7) and the alkyl alcohol (a1-2) is such that R ₂ and R ₃ of the general formula (1) are independently hydrogen atoms and alkyl groups, respectively. R ₂ and R ₃ are not hydrogen atoms at the same time. Further, the reaction products of the compound (a7) and the polyoxyethylene alkyl ether (a1-3) are such that R ₂ and R ₃ of the general formula (1) are independently hydrogen atoms and the general formula (2), respectively. ) Is an oxyalkylene group. R ₂ and R ₃ are not hydrogen atoms at the same time. However, in the formula, R ₇ and R ₈ are alkyl groups.

In the third method, the reaction product of the compound (a7) and the cyclic ether (a1-4) having an alkyl group is such that R ₂ and R ₃ of the general formula (1) are independently hydrogen atoms or, respectively. It is a hydroxyl group and an alkyl group represented by the general formula (3). R ₂ and R ₃ are not hydrogen atoms at the same time. Further, in the reaction product of the compound (a7) and the cyclic ether (a1-5) having a polyoxyalkylene alkyl ether group, R ₂ and R ₃ of the general formula (1) are independently hydrogen atoms. _{, Or the alkyl groups R 2} and R ₃ , which may be substituted with a hydroxyl group and / or an oxyalkylene group represented by the general formula (4), are not hydrogen atoms at the same time. However, in the formula, l is an integer of 1 to 20. R ₉ is independently an alkylene group having 2 to 4 carbon atoms. R ₇ and R ₁₀ are alkyl groups.

In the compounds shown in each production method, examples of the phosphoric acid derivative (a1-1) include orthophosphoric acid, metaphosphoric acid, phosphite, hypophosphoric acid, phosphonic acid, phosphinic acid, peroxo-phosphoric acid, and polyphosphorus. Examples thereof include acid, diphosphorus pentoxide, tetraphosphorus hexaoxide, and tetraphosphorus octoxide, but orthophosphoric acid and polyphosphoric acid are preferable in terms of ease of handling and reactivity.

Examples of the alkyl alcohol (a1-2) include 2-ethylhexyl alcohol, capryl alcohol, isooctyl alcohol, nonyl alcohol, isononyl alcohol, decyl alcohol, isodecyl alcohol, undecyl alcohol, lauryl alcohol, and tridecyl alcohol. Examples thereof include myristyl alcohol, pentadecyl alcohol, cetyl alcohol, heptadecyl alcohol, stearyl alcohol, isostearyl alcohol, nonadecil alcohol, araquil alcohol, behenyl alcohol, tetracosyl alcohol and the like. These can be used alone or in combination of two or more.

The polyoxyalkylene alkyl ether (a1-3) is a polyoxyalkylene alkyl ether having an alkyl group having 4 to 24 carbon atoms and an alkyleneoxy group having 2 to 4 carbon atoms repeating and having 2 to 20 units. For example, polyoxyethylene 2-ethylhexyl ether (the unit unit of "polyoxyethylene" is abbreviated as "EO", and the repeating unit is referred to as "additional molar number". EO additional molar number: 2- 20)), Polyoxypropylene 2-ethylhexyl ether ((The unit unit of "polypropylene" is abbreviated as "PO", and the repeating unit is referred to as "additional molar number". PO additional molar number: 2 to 20). ), Polyoxybutylene 2-ethylhexyl ether ((The unit unit of "polybutylene" is abbreviated as "BO", and the repeating unit is referred to as "additional molar number". BO additional molar number: 2 to 20)). Polyoxyethylene cetyl ether (number of EO addition moles: 2 to 20), polyoxyethylene lauryl ether (number of EO addition moles: 2 to 20), polyoxypropylene lauryl ether (number of PO addition moles: 2 to 20), polyoxy Ethylene cetyl ether (number of EO addition moles: 2 to 20), polyoxyethylene stearyl ether (number of EO addition moles: 2 to 20), polyoxyethylene isostearyl ether (number of EO addition moles: 2 to 20), polyoxyethylene Examples thereof include behenyl ether (number of moles added with EO: 2 to 20) and polyoxyethylene tetracosyl ether (number of moles added with EO: 2 to 20). These can be used alone or in combination of two or more.

As the cyclic ether having an alkyl group (a1-4), the cyclic ether having an alkyl group having 4 to 24 carbon atoms is preferable, and the cyclic ether having a 3-membered ring or a 4-membered ring is preferable. The alkyl group is preferably a mono-substituted group in view of reactivity.
For example, 2-ethylhexyl glycidyl ether, n-octyl glycidyl ether, isooctyl glycidyl ether, nonyl glycidyl ether, isonyl glycidyl ether, decyl glycidyl ether, isodecyl glycidyl ether, undecyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether. , Tetradecyl glycidyl ether, pentadecyl glycidyl ether, hexadecyl glycidyl ether, heptadecyl glycidyl ether, octadecyl glycidyl ether, 16-methyl-heptadecyl glycidyl ether, nonadecyl glycidyl ether, icosyl glycidyl ether, docosyl glycidyl ether, tetra Cosylglycidyl ether;

For example, 2-ethylhexyl (3-ethyl-3-oxetanylmethyl) ether, decyl (3-ethyl-3-oxetanylmethyl) ether, lauryl (3-ethyl-3-oxetanylmethyl) ether, cetyl (3-ethyl-3). Examples thereof include −oxetanylmethyl) ether, stearyl (3-ethyl-3-oxetanylmethyl) ether, isostearyl (3-ethyl-3-oxetanylmethyl) ether, and behenyl (3-ethyl-3-oxetanylmethyl) ether. These can be used alone or in combination of two or more.

As the cyclic ether (a1-5) having a polyoxyalkylene alkyl ether group, the above-mentioned alkyl group having 4 to 24 carbon atoms and the alkyleneoxy group having 2 to 4 carbon atoms are repeated and having 2 to 20 units. A cyclic ether having a polyoxyalkylene alkyl ether group is preferable, and a 3-membered ring or 4-membered ring cyclic ether is preferable. The polyoxyalkylene alkyl ether group is preferably a mono-substituted group in view of reactivity. For example, polyoxyethylene 2-ethylhexyl (3-ethyl-3-oxetanylmethyl) ether (number of moles of EO addition: 2 to 20), polyoxypropylene 2-ethylhexyl (3-ethyl-3-oxetanylmethyl) ether (PO addition). Number of moles: 2 to 20), polyoxybutylene 2-ethylhexyl (3-ethyl-3-oxetanylmethyl) ether (number of moles added to BO: 2 to 20), polyoxyethylene lauryl (3-ethyl-3-oxetanylmethyl) Ether (number of moles of EO added: 2 to 20), polyoxypropylene lauryl (3-ethyl-3-oxetanylmethyl) Ether (number of moles of PO added: 2 to 20), polyoxyethylene cetyl (3-ethyl-3-oxetanyl) Methyl) ether (number of moles of EO added: 2 to 20), polyoxyethylene stearyl (3-ethyl-3-oxetanylmethyl) ether (number of moles of EO added: 2 to 20), polyoxyethylene behenyl (3-ethyl-3) -Oxetanylmethyl) ether (number of moles added with EO: 2 to 20) and the like can be mentioned. These can be used alone or in combination of two or more.

The ethylenically unsaturated compound (a7) having a phosphoric acid group is a compound having a phosphoric acid group and an ethylenically unsaturated double bond group in its structure, and is an aromatic ring in terms of adhesion to a substrate. The number of carbon atoms of the alkylene group linked to the ethylenically unsaturated group and the phosphoric acid group is preferably 2 to 4 in terms of reactivity. However, the compound (a7) refers to a compound other than the compound (a1), the compound (a2), the compound (a3), the compound (a4) or the compound (a5). Examples of the compound (a7) include 2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyloxypropyl acid phosphate, 2- (meth) acryloyloxybutyl acid phosphate and the like. These can be used alone or in combination of two or more.

The ethylenically unsaturated compound having a hydroxyl group used in the first method and the third method is the ethylenically unsaturated compound (a4) having a hydroxyl group described later, and among them, ethylene is ethylene in terms of reactivity. A (meth) acrylic acid ester having 2 to 4 carbon atoms in the alkylene group linked to the unsaturated group and the hydroxyl group is preferable. Examples of the ethylenically unsaturated compound having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 1-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 3-hydroxypropyl (meth) acrylate. Examples thereof include hydroxypropyl, 1-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like. These can be used alone or in combination of two or more.

In the dehydration condensation reaction of the first method and the second method in the present invention, a catalyst and a polymerization inhibitor are added to the above mixture and charged in a closed container. At that time, the ratio of the phosphoric acid group and the ethylenically unsaturated group to 1 mol of the phosphoric acid group is preferably 0.9 to 1.5 mol, preferably 1.0 to 1.3 mol. Is more preferable, and 1.05 to 1.2 mol is most preferable. If the ratio of the ethylenically unsaturated group to the phosphoric acid group is less than 0.9 mol, the phosphoric acid esterification of the compound (a1) may be insufficient or the amount of by-product of the phosphoric acid diester may increase. If it exceeds 1.5 mol, the polymerization stability becomes poor or the effect of improving the removability of the aqueous pressure-sensitive adhesive cannot be obtained in producing the water-dispersible polymer (A) described later.
Then, the reaction temperature is kept at 60 to 120 ° C. with stirring, and the compound (a1) can be obtained by the reaction under reduced pressure of 50 torr or less for 6 to 12 hours. If the reaction temperature is less than 60 ° C, the reaction becomes insufficient, and if it exceeds 120 ° C, a transesterification reaction or a radical polymerization reaction of an ethylene unsaturated compound occurs to obtain the target compound (a1). You may not be able to.

Conventionally known catalysts can be used, and Li, Mg, Ca, Ba, La, Ce, Ti, Zr, Hf, V, Mn, Fe, Co, Ir, Ni, Zn, Ge, Sn can be used. Metal compounds containing metals such as, for example, organic acid salts, metal alkoxides and organic metal compounds such as metal complexes (acetylacetonate, etc.), metal oxides, metal hydroxides, carbonates, phosphates, sulfates, etc. Examples thereof include inorganic metal compounds such as nitrates and chlorides. Among the catalysts for these metal compounds, titanium compounds, particularly organic titanium compounds such as titanium alkoxides such as titanium tetraethoxydo, titanium tetraisopropoxide, and titanium tetrabutoxide are preferable. The amount of these metal compound catalysts used is preferably 0.001 to 5 parts by mass, more preferably 0.005 to 1 part by mass, with respect to 100 parts by mass of the mixture, but is not particularly limited. Can be used for.
Further, the polymerization inhibitor is effective in suppressing radical polymerization during the dehydration condensation reaction, and as the polymerization inhibitor, at least one selected from the group of hydroxy aromatics, for example, phenol compounds, hydroquinone compounds, and quinone compounds is used. Can be mentioned. Examples of such compounds include hydroquinone, p-methoxyphenol, cresol, t-butylcatechol, 3,5-di-t-butyl-4-hydroxytoluene, and 2,2'-methylenebis (4-methyl-6). -T-Butylphenol), 2,2'-methylenebis (4-ethyl-6-butylphenol), 4,4'-thiobis (3-methyl-6-t-butylphenol) and the like. The amount of the polymerization inhibitor used is 1 to 5000 ppm, preferably 5 to 1000 ppm, and more preferably 10 to 800 ppm with respect to 100 parts by mass of the mixture.

The ring-opening addition reaction of the third method in the present invention is not particularly limited, but the reaction can be easily controlled and the number of side reactants can be reduced. Add catalyst and charge in a closed container. At that time, similarly to the above, the ratio of the phosphoric acid group and the ethylenically unsaturated group to 1 mol of the phosphoric acid group is preferably 0.9 to 1.5 mol, and 1.0 to 1 mol. It is more preferably 3 mol, most preferably 1.05 to 1.2 mol.
Then, the temperature is raised with stirring, and the cyclic ether (a1-4) having an alkyl group and / or the cyclic ether (a1-5) having a polyoxyalkylene alkyl ether group is gradually added at a reaction temperature of 60 to 120 ° C. Drop and react. After the completion of the dropping, the cycloaddition reaction can be sufficiently advanced by further aging for 1 to 10 hours. At that time, the catalyst may be used or not used, but it is preferable to use the catalyst because it leads to an improvement in the reaction rate.

A conventionally known catalyst can be used, and the amount is preferably 0.001 to 5 parts by mass, more preferably 0.005 to 2 parts by mass, based on 100 parts by mass of the mixture. , Can be used without particular limitation. The catalyst is selected from the group consisting of rare earth Lewis acids, quaternary onium salts such as quaternary ammonium salts and quaternary phosphonium salts, tertiary amines, N-alkyl imidazoles, N-aryl imidazoles, and phosphazene compounds. At least one type of catalyst.
For example, lanthanum triflate, lanthanum acetylacetonate, lanterntris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate), europium triflate, Europium acetylacetonate, Europium tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanegeonate), ytterbium trifrate, ytterbium acetylacetonate, ytterbium Tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanegeonate), samarium trifrate, samarium acetylacetonate, samarium tris (6,6) Rare earths such as 7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedinate);

For example, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium iodide, tetraethylammonium bromide, tetraethylammonium chloride, tetraethylammonium iodide, n-dodecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, trimethylbenzylammonium bromide, cetyldimethyl. Benzylammonium chloride, cetyldimethylbenzylammonium bromide, cetylpyridium sulfate, tetraethylammonium acetate, trimethylbenzylammonium benzoate, trimethylbenzylammonium borate, 5-benzyl-1,5-diazabicyclo [4,3,0] -5-nonenium Tetra-ammonium salts, which are tetraammonium salts such as chloride, 5-benzyl-1,5-diazabicyclo [4,5,0] -5-noneumtetrafluoroborate;

For example, tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetraphenylphosphonium bromide, tetraphenylphosphonium iodide, tetraphenylphosphonium chloride, benzyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, triphenylmethoxymethylphosphonium chloride, triphenylmethyl. Fourth phosphonium salts such as carbonylmethylphosphonium chloride, triphenylethoxycarbonylmethylphosphonium chloride, trioctylbenzylhophonium chloride, trioctylmethylphosphonium chloride, trioctylethylphosphonium acetate, tetraoctylphosphonium chloride, trioctylethylphosphonium dimethylphosphate 4th onium salts;

For example, triethylamine, triisopropylamine, tri-n-butylamine, triphenylamine, N, N-dimethylaniline, N-methylpyrrolidin, 1,8-diazabicyclo [5.4.0] undece-7-ene (also known as:: DBU), triethylenediamine, 4-dimethylaminopyridine, N, N-diethylpropylamine, N-ethylpiperazin, benzyldimethylamine, tris (dimethylaminomethyl) phenol, 4- (N, N-dimethylamino) pyridine (also known as : Tertiary amines such as DMAP), 4- (N, N-diethylamino) pyridine;

For example, N such as N-methylimidazole (1-methyl-1H-imidazole), N-butylimidazole (1-butyl-1H-imidazole), 1,2-dimethylimidazole (1,2-dimethyl-1H-imidazole). -Alkylimidazoles;

For example, examples of N-arylimidazole include N-arylimidazoles such as N-phenylimidazole (1-phenyl-1H-imidazole) and N-2,4,6-trimethylphenylimidazole;

For example, phosphazene compounds such as tetrakis [tris (dimethylamino) phosphoranilideneamino] phosphonium hydroxide can be mentioned. These can be used alone or in combination of two or more. Among these, quaternary ammonium salts such as tetrabutylammonium bromide and tetraethylammonium acetate, tetrabutylphosphonium chloride, tetrabutylphosphonium bromide (TBPB), quaternary phosphonium salts such as tetrabutylphosphonium chloride, triethylamine, triisopropylamine and the like. The tertiary amines of No. 3 are preferable because they are industrially easily available and have high catalytic activity.

<< Ethylene unsaturated compound having a carboxyl group (a2) >>
Next, the ethylenically unsaturated compound (a2) having a carboxyl group will be described.
The ethylenically unsaturated compound (a2) having a carboxyl group is a compound having a carboxyl group or an acid anhydride group thereof ((-C = O) -O- (C = O)-)) in the molecule. By using the compound (a2), a carboxyl group or an acid anhydride group thereof is introduced into the water-dispersible polymer (A), so that the compound (a2) can be easily dispersed in water. Further, the water-based pressure-sensitive adhesive containing the water-dispersible polymer (A) can maintain an appropriate adhesive strength and durability.
Examples of such compound (a2) include (meth) acrylic acid, 2-carboxyethyl (meth) acrylate, 2-carboxypropyl (meth) acrylate, 3-carboxypropyl (meth) acrylate, and (meth). ) 4-carboxybutyl acrylate, (meth) acrylate dimer, maleic acid, fumaric acid, monomethylmaleic acid, monomethylfumaric acid, aconitic acid, sorbic acid, silicic acid, α-chlorosorbic acid, glutaconic acid, citraconic acid , Mesaconic acid, itaconic acid, tigric acid, angelic acid, senesioic acid, crotonic acid, isocrotonic acid, mucobromic acid, mucochloric acid, muconic acid, aconitic acid, penicic acid, gelanic acid, citronic acid, 4-acrylamide butanoic acid, 6 Polylactone-based (meth) having a carboxyl group at the end due to the ring-opening addition of the lactone ring, such as −acrylamide hexanoic acid, 2- (meth) acryloyloxyethyl succinate, mono (meth) acrylic acid ω-carboxypolycaprolactone ester. A carboxyl group-containing aliphatic acid such as an ester of an alkylene oxide-added succinic acid having a carboxyl group at the terminal and an ester of (meth) acrylic acid, to which an alkylene oxide such as an acrylic acid ester, ethylene oxide or propylene oxide is repeatedly added. Examples thereof include based ethylenically unsaturated double-bonding group-containing carboxylic acids and their acid anhydrides, and these may be used alone or in combination of two or more, but have flexibility and flexibility. From the viewpoint of maintaining the adhesiveness to the curved surface, it is preferable not to have an aromatic ring.

<< Ethylene unsaturated compound (a3) having an alkyl group having 4 to 24 carbon atoms >>
Subsequently, the ethylenically unsaturated compound (a3) having an alkyl group having 4 to 24 carbon atoms will be described.
The ethylenically unsaturated compound (a3) having an alkyl group having 4 to 24 carbon atoms has an ethylenically unsaturated double bond group and a linear or branched alkyl group having 4 to 24 carbon atoms in the molecule. It is a compound. By having an alkyl group having 4 to 24 carbon atoms, it is possible to control the flexibility and appropriate adhesiveness of the coating film. Examples of the compound (a3) include n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, pentyl acrylate, isoamyl acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, and (meth). 2-Ethylhexyl acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 3,4-dimethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, (meth) ) 3,4-Dimethylheptyl acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, cetyl (meth) acrylate, (meth) ) Isostearyl acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, tetracosyl (meth) acrylate and other (meth) acrylic acid alkyl esters;

For example, alkyl vinyl ethers such as butyl vinyl ether, hexyl vinyl ether, 2-ethylhexyl vinyl ether, octyl vinyl ether, nonyl vinyl ether, decyl vinyl ether, lauryl vinyl ether, stearyl vinyl ether;

For example, butyl (meth) allyl ether, hexyl (meth) allyl ether, 2-ethylhexyl (meth) allyl ether, octyl (meth) allyl ether, nonyl (meth) allyl ether, decyl (meth) allyl ether, lauryl (meth). Alkyl (meth) allyl ethers such as allyl ether and stearyl (meth) allyl ether can be mentioned, but the present invention is not particularly limited thereto. These may be used alone or in combination of two or more, but from the viewpoint of adhesiveness and flexibility, a (meth) acrylic acid ester having an alkyl group having 8 to 18 carbon atoms. Is preferable.

<< Ethylene unsaturated compound having a hydroxyl group (a4) >>
Subsequently, the ethylenically unsaturated compound (a4) having a hydroxyl group will be described.
The ethylenically unsaturated compound (a4) having a hydroxyl group is a compound having a hydroxyl group and an ethylenically unsaturated double bond group in its structure. However, the compound (a4) refers to a compound other than the above-mentioned compound (a1), compound (a2) or compound (a3).
By using the compound (a4) as a part of the constituent monomer as needed, the compound (a1), the compound (a2) or the compound (a2), which is a monomer unit constituting the water-dispersible polymer (A), is used. It may be easy to improve the efficiency of the copolymerization reaction with the compound (a3). Further, the viscosity of the water-dispersible polymer (A) can be controlled, and when the reactive compound (B) described later is blended, a reactive functional group capable of reacting with the hydroxyl group contained in the reactive compound (B). Since the cross-linking reaction with the compound proceeds and the cohesive force of the coated coating film can be expected to be improved, when it is used for re-peelability application, it not only has excellent heat resistance and moisture heat resistance, but also imparts sufficient workability. It becomes easy.

Examples of the compound (a4) include 2-hydroxyethyl (meth) acrylate, 1-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, ( 1-Hydroxybutyl acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, ( 8-Hydroxyoctyl acrylate, cyclohexanedimethanol mono (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, ethyl-α- (meth) acrylate Fatty acid esters such as hydroxymethyl), glycerol monofunctional (meth) acrylic acid, or (meth) glycidyl laurate ester of acrylic acid, glycidyl oleic acid ester of (meth) acrylic acid, and glycidyl oleic acid ester of (meth) acrylic acid. ) Acrylic acid ester or 2- (acryloyloxy) ethyl 6-hydroxyhexanone and other hydroxyl group-containing ethylenically unsaturated compounds have a hydroxyl group at the terminal obtained by ring-opening addition of ε-caprolactone. A hydroxyl group-containing fat such as an alkylene oxide-added (meth) acrylic acid ester in which an alkylene oxide such as ethylene oxide, propylene oxide, or butylene oxide is repeatedly added to the (meth) acrylic acid ester or the hydroxyl group-containing ethylenically unsaturated compound. Group (meth) acrylic acid esters;

For example, hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxyhexyl vinyl ether, hydroxyoctyl vinyl ether, hydroxydecyl vinyl ether, hydroxydodecyl vinyl ether, hydroxyoctadecyl vinyl ether, glyceryl vinyl ether, triethylene glycol monovinyl ether, tetraethylene glycol monovinyl ether, tri. Hydroxyl group-containing aliphatic vinyl ethers such as methylolpropane monovinyl ether, pentaerythritol monovinyl ether, or alkylene oxide-added vinyl ether having a hydroxyl group at the terminal to which alkylene oxides such as ethylene oxide and propylene oxide are repeatedly added;

For example, (meth) allyl alcohol, isopropenyl alcohol, dimethyl (meth) allyl alcohol, hydroxyethyl (meth) allyl ether, hydroxypropyl (meth) allyl ether, hydroxybutyl (meth) allyl ether, hydroxyhexyl (meth) allyl ether. , Hydroxyoctyl (meth) allyl ether, hydroxydecyl (meth) allyl ether, hydroxydodecyl (meth) allyl ether, hydroxyoctadecyl (meth) allyl ether, glyceryl (meth) allyl ether, or alkylene oxides such as ethylene oxide and propylene oxide. Hydroxyl-containing aliphatic (meth) allyl alcohols or (meth) allyl ethers such as an alkylene oxide-added system (meth) allyl ether having a hydroxyl group at the terminal to which the above is repeatedly added;

For example, it contains hydroxyl groups such as N-hydroxyethyl (meth) acrylamide, N-hydroxypropyl (meth) acrylamide, N-hydroxybutyl (meth) acrylamide, N-hydroxyhexyl (meth) acrylamide, and N-hydroxyoctyl (meth) acrylamide. (Meta) acrylamides and the like, but are not particularly limited thereto. Only one of these may be used, or a plurality of types may be used in combination.

Examples of the compound (a4) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc. from the viewpoint of improving the adhesion to the substrate. Open ε-caprolactone for hydroxyl group-containing ethylenically unsaturated compounds such as fatty acid ester-based (meth) acrylic acid ester having 2 to 10 carbon atoms and 2-hydroxyethyl ε-caprolactone (meth) acrylate. A hydroxyl group-containing aliphatic vinyl ether such as a (meth) acrylic acid ester having a hydroxyl group at the terminal having 2 to 10 carbon atoms and a hydroxyethyl vinyl ether obtained by ring addition, and a hydroxyl group-containing (meth) such as N-hydroxyethyl acrylamide. An ethylenically unsaturated compound having 2 to 10 carbon atoms such as acrylamide is preferable.

<< Ethylene unsaturated compound having a carbonyl group (a5) >>
Subsequently, the ethylenically unsaturated compound (a5) having a carbonyl group will be described.
The ethylenically unsaturated compound (a5) having a carbonyl group is a compound having a carbonyl group and an ethylenically unsaturated double bond group in its structure. However, the compound (a5) does not contain a hydroxyl group and refers to a compound other than the above-mentioned compound (a1), compound (a2), compound (a3) or compound (a4). Further, among the ethylenically unsaturated compounds, the carbon-oxygen double bond directly bonded to the carbon-carbon double bond represented by the (meth) acryloyl group is not included in the above-mentioned "carbonyl group". .. Further, although the carbonyl group is derived from the acyl group, the carbon-oxygen double bond contained in the carboxyl group, the acid anhydride group (-C (= O) OC (= O)-), the amide group and the ester group is also present. It shall not be included in the above "carbonyl group".

For example, 2-oxobutanoylethyl (meth) acrylate, 2-oxobutanoylpropyl (meth) acrylate, 2-oxobutanoylbutyl (meth) acrylate, 2-oxobutanoylhexyl (meth) acrylate, 2-oxobutanoyloctyl (meth) acrylate, 2-oxobutanoyldecyl (meth) acrylate, 2-oxobutanoyldodecyl (meth) acrylate, 3-oxobutanoylethyl (meth) acrylate, (meth) ) 3-oxobutanoylpropyl acrylate, 3-oxobutanoylbutyl (meth) acrylate, 3-oxobutanoylhexyl (meth) acrylate, 3-oxobutanoyloctyl (meth) acrylate, (meth) acrylic 3-oxobutanoyldecyl acid, 3-oxobutanoyldodecyl (meth) acrylate, 4-cyanooxobutanoylethyl (meth) acrylate, 4-cyanooxobutanoylpropyl (meth) acrylate, (meth) acrylic Acid 4-cyanooxobutanoylbutyl, (meth) acrylic acid 4-cyanooxobutanoylhexyl, (meth) acrylic acid 4-cyanooxobutanoyloctyl, (meth) acrylic acid 2,3-di (oxobutanoyl) Propyl, (meth) acrylic acid 2,3-di (oxobutanoyl) butyl, (meth) acrylic acid 2,3-di (oxobutanoyl) hexyl, (meth) acrylic acid 2,3-di (oxobutanoyl) ) An aliphatic (meth) acrylic acid ester having two carbonyl groups such as octyl;

For example, N- (2-oxobutanoylethyl) (meth) acrylamide, N- (2-oxobutanoylpropyl) (meth) acrylamide, N- (2-oxobutanoylbutyl) (meth) acrylamide, N-( It has carbonyl groups such as 2-oxobutanoylhexyl) (meth) acrylamide, N- (2-oxobutanoyloctyl) (meth) acrylamide, and N- (1,1-dimethyl-3-oxobutyl) (meth) acrylamide. Examples of (meta) acrylamides are not particularly limited to these, but it is preferable that they do not have an aromatic ring. Only one of these may be used, or a plurality of types may be used in combination.

As described above, the compound (a5) can be introduced into the water-dispersible polymer (A) by using it as a monomer unit constituting the water-dispersible polymer (A). By having a carbonyl group in this way, one or more kinds selected from the group consisting of nitrogen-containing substituents having active hydrogen such as an amino group, an imino group, and a hydrazino group contained in the reactive compound (B) described later. It is possible to form a crosslinked structure by the interaction of the substituent with the Michael addition reaction or the like. Therefore, the adhesive sheet formed by coating is attached to the substrate described below using the aqueous pressure-sensitive adhesive of the present invention containing the water-dispersible polymer (A) and the reactive compound (B) described later. Even if it is exposed for a long period of time under heating and humidifying heat conditions, the occurrence of deterioration phenomena such as foaming, floating and peeling is remarkably suppressed, durability such as heat resistance and moist heat resistance is remarkably improved, and the adhesive sheet is used. When peeled from the adherend, there is an advantage that the surface of the adherend can be prevented from being contaminated with the adherend such as cloudiness and adhesive residue.

Among the above compounds (a5), carbonyl groups such as 2-oxobutanoylethyl acrylate and 2-oxobutanoyl ethyl methacrylate are selected in consideration of Michael addition reactivity, price, and industrial availability. Two aliphatic (meth) acrylic acid esters and aliphatic (meth) acrylamides having one carbonyl group such as N- (1,1-dimethyl-3-oxobutyl) acrylamide are particularly preferable.

<< Other Ethylene Unsaturated Compounds (a6) >>
Subsequently, the other ethylenically unsaturated compound (a6) will be described.
The other ethylenically unsaturated compound (a6) is an ethylenically unsaturated compound other than the above-mentioned compound (a1), compound (a2), compound (a3), compound (a4), compound (a5) and compound (a7). ..
By using the compound (a6) as a part of the constituent monomer as needed, the compound (a1), the compound (a2), which are the monomer units constituting the water-dispersible polymer (A), It may be easy to improve the efficiency of the copolymerization reaction with the compound (a3), the compound (a4) or the compound (a5). In addition, the viscosity of the water-dispersible polymer (A) can be controlled, and it becomes easy to improve the workability of the water-dispersible polymer (A) at the time of emulsification, as well as good adhesive strength and various resistances. , And various physical properties such as flexibility may be appropriately controlled.

Examples of such compound (a6) include (meth) acrylic acid alkyl esters such as methyl (meth) acrylate and (meth) ethyl acrylate; vinyl esters such as vinyl acetate and vinyl propionate; (meth). ) Acrylamides such as acrylamide and dimethyl (meth) acrylamide; vinyl ethers such as ethyl vinyl ether and propyl vinyl ether; (meth) acrylic acid alkoxy such as 2-methoxyethyl (meth) acrylate and 2-ethoxyethyl (meth) acrylate. Esters; (meth) methoxydiethylene glycol acrylate, (meth) methoxypolyoxyethylene acrylate (number of moles added by EO: 3 to 20), (meth) methoxypolyoxypropylene acrylate (number of moles added by PO: 2 to 20) (Meta) acrylic acid esters having alkylene oxides such as; In addition, (meth) acrylonitrile, (meth) acrylic acid perfluoromethyl, 3- (meth) acryloyloxypropylmethyldimethoxysilane, etc. are mentioned, and these are one kind. Acrylic acid may be used alone, or a plurality of types may be used in combination, but it is preferable not to have an aromatic ring from the viewpoint of removability, adhesion to a substrate, and maintenance of curved surface adhesiveness.

<< Water-dispersible polymer (A) >>
The water-dispersible polymer (A) is obtained by copolymerizing the compound (a1), the compound (a2) and the compound (a3) with the compound (a4), the compound (a5) and the compound (a6), if necessary. Obtainable. Among the above-mentioned monomers, a compound having a (meth) acryloyl group is preferable from the viewpoint of reactivity. In various ethylenically unsaturated compounds, thus, control of the viscosity and emulsifying property of the water-dispersible polymer (A), particle size and storage stability, adhesiveness and removability of the adhesive sheet, and durability. , The compound (a1), the compound (a2) and the compound (a3) are appropriately selected based on the coating suitability and the like, and the compound (a4), the compound (a5) and the compound (a6) are selected as necessary. Is possible.

The water-dispersible polymer (A) is synthesized by a method such as bulk polymerization, solution polymerization, emulsion polymerization or suspension polymerization of various monomeric mixtures of ethylenically unsaturated compounds as described above according to a conventional method. .. The polymerization method and reaction operation are not particularly limited, but emulsion polymerization is preferable. In the case of emulsion polymerization, a monomer mixture of various ethylenically unsaturated compounds as described above, a polymerization initiator, and a surfactant are used as main components, and water is used as a medium for polymerization.
The usual emulsification polymerization method is carried out by emulsifying a monomer mixture of various ethylenically unsaturated compounds in water with a surfactant and adding a water-soluble polymerization initiator to this system (also referred to as a pre-emulsification method). Since the polymerization proceeds in micelles formed by the surfactant, it is possible to produce a resin having a high molecular weight that cannot be obtained by other polymerization methods. Moreover, since no organic solvent is used, a high polymerization reaction rate can be expected, and the particle size and viscosity can be controlled.

The polymerization initiator used for emulsion polymerization is usually 0.001 to 5.0 parts by mass with respect to a total of 100 parts by mass of the monomer mixture of various ethylenically unsaturated compounds as described above. The present invention is not particularly limited, and the water-soluble polymerization initiator and the oil-soluble polymerization initiator can be appropriately selected and used.

Examples of the water-soluble polymerization initiator include potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, and ammonium (amine) salts of 4,4'-azobis-4-cyanovaleric acid.

Examples of the oil-soluble polymerization initiator include alkylpaoxide, t-butylhydropaoxide, cumenehydropaoxide, p-methanehydropaoxide, lauroylpaoxide, 3,5,5-trimethylhexanoylpaoxide, and octanoylpaoxide. , T-butylcumylpaoxide, benzoylpaoxide, dichlorobenzoylpaoxide, dicumylpaoxide, di-t-butylpaoxide, 1,1-bis (t-butylpaoxy) -3,3,5-trimethyl Cyclohexane, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, di-isobutylpa-oxydicarbonate, di-2-ethylhexylpa-oxydicarbonate, t-butylpa-oxyisobuty Organic peroxides such as rates, 2,2'-azobisisobutyronitrile, dimethyl-2,2'-azobisisobutyrate, 2,2'-azobis (2,4-dimethylvaleronitrile), 2 , 2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2-methylamide oxime) dihydrochloride, 2,2'-azobis (2-methylbutanamide oxime) dihydrochloride tetrahydrate, 2,2'-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] -propionamide}, 2,2'-azobis [2-methyl-N- (2-methyl-N- (2-) Hydroxyethyl) -propionamide] and other azo compounds and the like can be mentioned.

Further, as the polymerization initiator, a redox initiator in which an oxidizing agent and a reducing agent are used in combination can also be preferably used.
Examples of the oxidizing agent include ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, t-butyl hydroperoxide, benzoyl peroxide and the like.
Examples of the reducing agent include sodium sulfite, acidic sodium sulfite, sodium formaldehyde sulfoxylate dihydrate (also known as longalit), ascorbic acid and the like.

In addition, a buffer can be used to adjust the pH as needed during emulsion polymerization. The buffer is not particularly limited as long as it has a pH buffering action on the reaction solution of emulsion polymerization. Examples of the buffer include sodium hydrogen carbonate, potassium hydrogen carbonate, monosodium phosphate, monopotassium phosphate, disodium phosphate, trisodium phosphate, sodium acetate, ammonium acetate, sodium formate, ammonium formate, and trisodium citrate. Examples include sodium and the like.
The buffer is preferably used in an amount of less than 5 parts by mass, more preferably less than 3 parts by mass, based on a total of 100 parts by mass of the monomer mixture of various ethylenically unsaturated compounds as described above.

Further, at the time of emulsion polymerization, it is also possible to appropriately adjust the molecular weight of the water-dispersible polymer (A) by using a chain transfer agent. As the chain transfer agent, for example, a thiol compound such as a mercaptan compound, a thioglycol compound, or β-mercaptopropionic acid may be used.

The polymerization conditions for the polymerization reaction of the water-dispersible polymer (A) may be appropriately set according to the polymerization method, and are not particularly limited. The polymerization temperature is preferably 20 to 150 ° C, more preferably 40 to 120 ° C. The reaction time may be appropriately set so that the polymerization reaction of each component of the ethylenically unsaturated compound is completed.

As the monomer unit constituting the water-dispersible polymer (A), the compound (a1) 0.1 to 10% by mass and the compound (a2) 0.1 to 1% by mass in 100% by mass of the water-dispersible polymer (A). It preferably contains 10% by mass and 80-99.8% by mass of compound (a3).
More preferably, it is in the range of 0.5 to 8% by mass of compound (a1), 0.2 to 5% by mass of compound (a2), and 87 to 99.3% by mass of compound (a3).

When the compound (a4) and / or the compound (a5) is contained as a monomer unit, if necessary, in 100% by mass of the water-dispersible polymer (A),
Compound (a1) 0.1 to 10% by mass, compound (a2) 0.1 to 10% by mass, compound (a3) 65 to 99.78% by mass, compound (a4) 0 to 10% by mass, and compound (a5). ) 0 to 5% by mass, preferably
Compound (a1) 0.5 to 8% by mass, compound (a2) 0.2 to 5% by mass, compound (a3) 79 to 99.3% by mass, compound (a4) 0 to 5% by mass, and compound (a5). ) More preferably in the range of 0 to 3% by mass. However, the total of the compound (a4) and the compound (a5) is more than 0% by mass and 15% by mass or less, and does not become 0% by mass.

When the content of each monomer is within the above range, the phosphate ester structure in the adhesive layer is oriented toward the surface of the adherend, the surface polarity of the adhesive layer can be changed, and the fragrance is further increased. Since it does not have a ring, it is flexible and exhibits appropriate adhesiveness, but when peeled off, contamination of the adherend such as cloudiness and adhesive residue is suppressed, so that the water-dispersible copolymer (A) ) Acid polarity (AV), glass transition temperature (hereinafter, may be abbreviated as "Tg"), adhesive strength, curved surface adhesiveness, various resistances, flexibility, compatibility, emulsifying property, removability, etc. It is possible to appropriately control various physical properties.

The water-dispersible polymer (A) has a glass transition point (Tg) of -80 to -10 ° C. so that the water-dispersible polymer (A) can sufficiently exhibit good adhesiveness and removability. , More preferably, the composition ratio of each monomer which is a constituent component of the water-dispersible polymer is selected so as to be −70 to −10 ° C. When Tg is within the above range, not only the emulsification of the water-dispersible polymer (A) becomes easy, but also the adhesion obtained from the water-based pressure-sensitive adhesive containing the approximately water-dispersible polymer (A). It is possible to maintain processability such as punching and cutting while maintaining the flexibility of the sheet. The Tg of the water-dispersible polymer (A) in the present invention was determined by using a differential scanning calorimetry (DSC) described later. Details of the method for measuring the glass transition temperature (Tg) are described in Examples.

The acid value (AV) of the water-dispersible polymer (A) is preferably in the range of 1 to 100, more preferably in the range of 2 to 50, and even more preferably 5 to 20 mgKOH / g. The acid value (AV) is a value measured in accordance with JIS K0070: 1992.
When the acid value (AV) is in the above range, the viscosity of the water-dispersible polymer can be lowered and the emulsifying property is also good, so that the particle size can be easily controlled in the range of 0.01 to 10 μm. .. Details of the acid value (AV) measurement method are described in Examples.

<Reactive surfactant (B)>
Next, the reactive surfactant (B) will be described.
The water-dispersible polymer can be obtained by emulsion polymerization of the above-mentioned monomer mixture. The surfactant used in the emulsion polymerization is preferably selected from anionic surfactants and / or nonionic surfactants as appropriate. Further, the surfactant may be a normal non-reactive surfactant having no radically polymerizable ethylenically unsaturated group, but a reactive surfactant having a radically polymerizable ethylenically unsaturated group. It is preferable to include (B). By containing the reactive surfactant (B), when the adhesive sheet is peeled off from the adherend, it becomes possible to prevent fogging and adhesive residue derived from the surfactant, and the re-peeling property is improved.

As the reactive surfactant (B), various known reactive surfactants of anionic and / or nonionic properties can be used without particular limitation, but an anionic reactive surfactant is essential. It is preferably contained alone or in combination with a nonionic surfactant. The content thereof is preferably 0.1 to 10 parts by mass, preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the water-dispersible polymer (A). When the reactive surfactant (B) is contained in the above range, the adhesive layer does not impair the water resistance and moisture heat resistance, exhibits good removability, and further improves the storage stability of the water-based pressure-sensitive adhesive. It becomes possible to secure. Further, it is preferable not to have an aromatic ring in terms of peel strength, flexibility, and re-peelability. The reactive surfactant (B) is other than the above-mentioned compound (a1), compound (a2), compound (a3), compound (a4) and compound (a5).
When the reactive surfactant (B) is used during emulsion polymerization in the production of the water-dispersible polymer (A), the reactive surfactant (B) becomes a constituent unit of the polymer (A). It is preferably contained in an amount of 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the compound constituting the polymer (A) other than the reactive surfactant (B). desirable. When a non-reactive surfactant is used during emulsion polymerization, it is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the compound constituting the polymer (A). It is desirable to contain by mass.

Examples of the anionic reactive surfactant include polyoxyethylene alkylpropenyl ether sulfate ammonium, polyoxyethylene styrenated propenylphenyl ether sulfate ammonium, and α-sulfo-ω- {1- (nonylphenoxy) methyl-. 2- (2-Propenyloxy) ethoxy} -poly (oxy-1,2-ethanediyl) ammonium, polycyclic phenyl ether methacrylate ester ammonium, polyoxyethylene polycyclic phenyl ether sulfate ester, 2-dimethylaminoethyl methacrylate, etc. Polyoxyethylene alkyl alkenyl phenyl ether sulfate ester salt;

For example, α-sulfo-ω- {1-alkoxymethyl-2- (2-propenyloxy) ethoxy} -poly (oxy-1,2-ethanediyl) ammonium, polyoxyethylene-1- (allyloxymethyl) alkyl ether. Polyoxyethylene alkyl alkenyl ether sulfate salts such as ammonium sulfate, polyoxyalkylene alkyl ether ammonium sulfate, and sodium methacryloyloxypolyoxypropylene sulfate;

Examples thereof include succinic acid and phosphoric acid-based surfactants such as alkyl sulfosuccinate alkenyl ether, alkyl alkenyl succinate ester, and alkyl alkenyl phosphoric acid ester. These can be used alone or in combination of two or more.

Examples of the nonionic reactive surfactant include polyoxyethylene alkylpropenylphenyl ether, allyloxymethylalkoxyethyl hydroxypolyoxyethylene, polyoxyalkylene alkenyl ether, alkoxypolyethylene glycol methacrylate, alkoxypolyethylene glycol maleic acid ester, and poly. Examples thereof include alkylene glycol mono (meth) acrylate. These can be used alone or in combination of two or more.

The reactive surfactant (B) preferably contains an anionic reactive surfactant as described above, and further has no aromatic ring, in terms of adhesion to the base material which is the support. It is preferable to contain an ethylene alkylalkenyl ether sulfate ester salt.

<Reactive compound (C)>
Next, the reactive compound (C) will be described.
In one embodiment of the water-based pressure-sensitive adhesive of the present invention, the reactive compound (C) is used as a cross-linking agent for the water-dispersible polymer for cross-linking between the particles of the water-dispersible polymer (A). Can be done. The compound (C) is a compound that can react with the water-dispersible polymer (A) and is other than the reactive surfactant (B).
The cross-linking agent for the water-dispersible polymer is essentially non-reactive to the water-dispersion particles in the water-dispersion liquid, but when water is removed from the water-dispersion liquid by drying, the water-dispersible polymer A chemical reaction occurs between the functional group contained in the water-dispersible polymer and the functional group contained in the cross-linking agent for the water-dispersible polymer, and a covalent bond is formed between the particles. This reaction proceeds at high speed under ambient conditions, and the aqueous dispersion particles can be regarded as interparticle cross-linking, that is, externally cross-linked (also known as external cross-linking). That is, the reactive compound (C) in the present invention is a compound that forms an interparticle crosslink between particles in a short time when water is removed. By performing interparticle cross-linking using the reactive compound (C) in this way, it is possible to prevent the transfer from the adhesive layer to the adherend when the adhesive sheet is peeled off, resulting in adhesive residue and cloudiness. It is less likely to occur and the removability is improved.

In the present invention, when the reactive compound (C) has at least one of a hydroxyl group and a carbonyl group in the water-dispersible polymer (A), at least one of the hydroxyl group and the carbonyl group. It has a functional group capable of reacting with, and is preferably contained in an amount of 0.01 to 20 parts by mass with respect to 100 parts by mass of the water-dispersible polymer (A). When the reactive compound (C) is in this range, when the water-dispersible polymer (A) has at least one of a hydroxyl group and a carbonyl group, the heat resistance and the moist heat resistance are improved by the crosslinking reaction. In addition to this, the floating, peeling, or foaming of the adhesive layer in a harsh environment can be further suppressed, and the removability is further improved.

When the water-dispersible polymer (A) has a hydroxyl group, the functional groups capable of reacting with the hydroxyl group in the reactive compound (C) include an isocyanate group (isocyanato group), an alkoxysilyl group, and a methylol group. , Phosphono group, hydroxyboryl group (BOH) and the like, and a compound having two or more functional groups in the molecule capable of reacting with the hydroxyl group of the water-dispersible polymer (A) is preferably used. In particular, the boric acid derivative (c1) having a hydroxyboryl group is preferably used because it is excellent in adhesiveness after a cross-linking reaction and adhesion to a substrate described later.

The boric derivative (c1) includes a large number of boron-containing compounds having one or more hydroxyboryl groups in the molecule or hydrolyzing in the presence of water to form one or more hydroxyboryl groups. It can be suitably used without limitation. For example, boric acid oxide (eg, B ₂ O ₃ );
For example, those obtained by the reaction of boric acid with alcohol or phenol, such as trimethyl borate, triethyl borate, tri-n-propyl borate, tri-n-butyl borate, triphenyl borate, tri borate. Isopropyl, tri-t-amyl borate, triphenyl borate, trimethoxyboroxin, tri-2-cyclohexylcyclohexyl borate, triethanolamine borate, triisopropylamine borate, mannitol borate, glycerol borate, and Examples thereof include boric acid esters such as triisopropanolamine borate.
The boric acid derivative (c1) also includes a boronic acid derivative. For example, alkylboronic acids such as methylboronic acid, ethylboronic acid, and butylboronic acid; etc. may be mentioned, and these may be used alone or in combination of two or more, but have removability and a group. From the viewpoint of adhesion to the material and maintenance of curved surface adhesiveness, it is preferable not to have an aromatic ring.
Among these, boric acid oxide is more preferable from the viewpoint of stability and reactivity of the water-dispersible polymer.

As described above, the boric acid derivative (c1) is preferably contained in an amount of 0.01 to 20 parts by mass with respect to 100 parts by mass of the water-dispersible polymer (A), more preferably 0.1 to 10 parts by mass. , 0.5 to 5 parts by mass is more preferable. When the boric acid derivative (c1) is in this range, the crosslink density is sufficiently improved, which leads to the improvement of moist heat resistance and removability.

When the water-dispersible polymer (A) has a carbonyl group, the functional groups capable of reacting with the carbonyl group in the reactive compound (C) include a hydroxyl group, an amino group, an imino group and a hydradino. One or more substituents selected from the group consisting of a group consisting of a nitrogen-containing heterocyclic group having an active hydrogen can be mentioned, and two functional groups capable of reacting with the carbonyl group of the water-dispersible polymer (A) are included in the molecule. The compounds having the above are preferably used. In particular, the hydrazine derivative (c2) having a hydrazino group is preferably used because it is excellent in adhesiveness after the cross-linking reaction and adhesion to the substrate described later.

As the hydrazine derivative (c2) _{, any compound having one or more hydrazine groups (-NHNH 2} ) in the molecule can be preferably used without limitation. For example, carbodihydrazide, dihydrazide oxalic acid, dihydrazide malonic acid, dihydrazide succinate, dihydrazide glutarate, dihydrazide adipic acid, dihydrazide sebacic acid, dihydrazide maleate, dihydrazide fumaric acid, dihydrazide itaconate, dihydrazide hydrazine-1, Dicarboxylic acid dihydrazides such as -1,3-dihydrazine, butylene-1,4-dihydrazine, 1,3-bis (hydradinocarbonoethyl) -5-isopropylhydranthin;

For example, tricarboxylic acid trihydrazides such as citrate trihydrazide, nitriloacetate trihydrazide, 1,8-dihydrazide-4-hydrazide methyloctane;

For example, tetracarboxylic acid tetrahydrazides such as pyromellitic acid tetrahydrazide, 1,4,5,8-naphthoic acid tetrahydrazide, ethylenediaminetetraacetic acid tetrahydrazide and the like can be mentioned, and only one of these may be used. Alternatively, a plurality of types may be used in combination, but it is preferable not to have an aromatic ring from the viewpoint of removability, adhesion to the substrate, and maintenance of curved surface adhesiveness. Among these, adipic acid dihydrazide is more preferable from the viewpoint of stability and reactivity of the water-dispersible polymer.

As described above, the hydrazine derivative (c2) is preferably contained in an amount of 0.01 to 20 parts by mass, more preferably 0.01 to 5 parts by mass, based on 100 parts by mass of the water-dispersible polymer (A). 0.01 to 1 part by mass is more preferable. When the hydrazine derivative (c2) is in this range, the crosslink density is sufficiently improved, which leads to improvement in moisture heat resistance and removability.

<Other compounds (F)>
Next, the other compound (F) will be described.
In one embodiment of the water-based pressure-sensitive adhesive of the present invention, the water-dispersible polymer may further contain the other compound (F) in addition to the above-mentioned essential components as long as the problem can be solved.
The other compound (F) is a compound other than the above-mentioned water-dispersible polymer (A), reactive surfactant (B) and reactive compound (C), and the material is stabilized by adding a small amount of components. It is a compound that has the function of improving properties and physical properties. For example, thickeners, plasticizers, preservatives, rust inhibitors, freeze-melt stabilizers, colorants, fillers, wetting agents, antioxidants, flame retardants, storage stabilizers, UV absorbers, thixotropy-imparting agents, dispersions. Examples thereof include stabilizers, fluidity imparting agents, film forming aids, moisturizing agents, pH adjusting agents, leveling agents, defoaming agents, viscosity adjusting agents, and other additives.

<Water-based pressure-sensitive adhesive>
Next, the water-based pressure-sensitive adhesive will be described.
As described above, the aqueous pressure-sensitive adhesive of the present invention contains the reactive surfactant (B), the reactive compound (C) and other compounds (F) in addition to the water-dispersible polymer (A), if necessary. ) Coexist.
The non-volatile content concentration of the water-based pressure-sensitive adhesive is not particularly limited, but it is usually adjusted to about 40 to 70% depending on the usage pattern. In addition, if necessary, additional water may be used to adjust the viscosity. Furthermore, the viscosity can be reduced by heating the aqueous pressure sensitive adhesive without the use of additional moisture.
Further, when the adhesive layer is formed by using the water-based pressure-sensitive adhesive of the present invention, the water-dispersible polymer (A) is the main agent from the viewpoint of forming a coating film, so that the water-based pressure-sensitive adhesive is used. The average particle size is not significantly different from the average particle size of the water-dispersible polymer (A) having a non-volatile content concentration of about 55% by mass, and is usually about 0.05 to 10 μm, and most of the particles are uniform as particles of 1 μm or less. It is emulsified and dispersed. The water-based pressure-sensitive adhesive has a white to milky white appearance and has a pH value of about 5 to 11.

When the adhesive layer is formed using the water-based pressure-sensitive adhesive of the present invention, the thickness of the adhesive layer is preferably 0.5 to 100 μm, more preferably 1 to 50 μm. When the film thickness is in the above range, it is possible to obtain a sufficient adhesive force.
Therefore, from the viewpoint of coating film formation and performance, the viscosity of the water-based pressure-sensitive adhesive is in the range of 500 to 30,000 mPa · s when measured with a B-type viscometer at 25 ° C. It is preferably in the range of 1,000 to 15,000 mPa · s. When the viscosity is 30,000 mPa · s or less, a thin film of 0.5 to 100 μm can be easily formed on the base material by coating, and it is also easy to enhance the adhesive physical properties such as tack, adhesive force and holding force. Is. On the other hand, when the viscosity is 1,000 mPa · s or more, it is easy to control the film thickness of the adhesive layer formed from the water-based pressure-sensitive adhesive. In the present embodiment, the film thickness, viscosity, or non-volatile content concentration of the adhesive layer is set according to the use of the laminated body.

Further, in order to show good removability, the water-based pressure-sensitive adhesive preferably has a gel fraction (Gel%) of 85% or more with respect to ethyl acetate in the dry coating film, and is 90% or more and less than 95%. More preferably. When Gel% is in this range, when the adhesive sheet formed of the water-based pressure-sensitive adhesive is left in a high temperature atmosphere, the cohesive force of the adhesive layer is not reduced and the adhesive force is good but adhered. Since the agent layer and the adherend are not excessively adhered to each other, the removability is improved. The details of the method for measuring the gel fraction (Gel%) of the dry coating film with respect to ethyl acetate will be described in Examples.

<Adhesive sheet>
Next, the adhesive sheet will be described.
The adhesive sheet (also referred to as an adhesive film) of the present invention includes a base material which is a support described later and an adhesive layer formed from the above-mentioned water-based pressure-sensitive adhesive. The adhesive layer may be laminated with a sheet-like base material (also referred to as a release liner) whose surface has been further peeled off.
As a method for producing an adhesive sheet, a method of applying a water-based pressure-sensitive adhesive to a base material and then removing water by a method such as heating to form an adhesive layer on the base material, or a release liner. Examples thereof include a method in which a water-based pressure-sensitive adhesive is applied to the peeled surface of the above, dried, and the base materials are bonded together.

The method of applying the water-based pressure-sensitive adhesive is not particularly limited. For example, various well-known methods such as Meyer bar, applicator, brush, spray, roller, gravure coater, die coater, kiss coater, lip coater, comma coater, blade coater, knife coater, reverse coater, spin coater, dip coater, etc. Can be applied. Further, the form of thin film coating or thick film coating can also be selected without particular limitation depending on the application.

The basic laminated structure of the adhesive sheet is a single-sided adhesive sheet such as a base material / adhesive layer / release liner, or a double-sided adhesive sheet such as a release liner / adhesive layer / base material / adhesive layer / release liner. .. The laminated body laminated on the release liner in this way is called an adhesive sheet. At the time of use, the release liner is peeled off and the adhesive layer is attached to the adherend. In the water-based pressure-sensitive adhesive, not only the adhesive layer has adhesiveness at the moment when the adhesive layer touches the adherend at the time of adhesion, but also an adhesive other than the pressure-sensitive adhesive (hereinafter, simply referred to as an adhesive). ), It is necessary to have a cohesive force for maintaining the sticking state while having a tack and an appropriate hardness without completely solidifying during sticking. The cohesive force largely depends on the molecular weight and the cross-linking density. A laminate that is laminated in the structure of the base material / adhesive layer / adherend in this way is called a sticking laminate.

The adhesive sheet using the water-based pressure-sensitive adhesive of the present invention is used for a wide range of applications of various known adhesive products (labels, seals, tapes, stickers, etc.), and the water-based pressure-sensitive adhesive has two or more. An adhesive layer is formed to bond the base materials (one of the base materials is the base base material of the adhesive sheet, and the other base material is the base material to which the base material is attached (referred to as an adherend)). The water-based pressure-sensitive adhesive of the present invention is generally used for various labels such as general paper, kraft paper, metal, glass, plastic, rubber, wood, and painted surfaces, masking tape applications, protective film applications, and concrete. , Cement mortar, various metals, leather, glass, vinyl chloride sheet, decorative paper, plywood panel, building material used for bonding materials such as gypsum board, ceiling material, decorative parts, door rims, seat seats, instrument panels , Dash silencer, center console, pillar trim, rear parcel and other automobile interior materials, and wire binding tape and other wire coating materials.
Among these, the application is not particularly limited, but it can be suitably used for various labels, masking tape applications, protective film applications, and the like.

As the base material, a plate material or sheet such as paper, cellophane, plastic sheet, rubber, foam, cloth, rubberized cloth, resin impregnated cloth, glass plate, metal plate, wood, optical film such as polarizing plate, etc. Can be mentioned. Further, the base material may be a single material or a laminated body. Further, the base material can be peeled off or antistatic treated on the back surface (the surface opposite to the surface to which the adhesive layer is directly bonded). Further, the base material can be coated with a known anchoring agent to improve the adhesion to the adhesive layer.

As described above, examples of the peeling liner include those obtained by peeling the surface of a sheet-like base material such as cellophane, various plastic sheets, paper, and metal foil. Further, the sheet-like base material may be a single layer or a material in a multi-layered state in which a plurality of base materials are laminated.

Hereinafter, specific examples of the present invention will be described together with comparative examples, but the present invention is not limited to the following examples. Further, in the following Examples and Comparative Examples, "parts" and "%" represent "parts by mass" and "% by mass", respectively, unless otherwise specified.

<Synthesis of compound (a1)>
(Synthesis Example 1) First Method The following compounds, catalysts and polymerization inhibitors are placed in the reaction tank of a reactor equipped with a reaction tank, a stirrer, a thermometer, a reflux condenser, a nitrogen introduction pipe and an air introduction pipe, respectively. It was prepared in proportion.

[Reaction tank]
Orthophosphoric acid (a1-1) 20.9 parts 2-ethylhexyl alcohol (a1-2) 52.4 parts 2-hydroxyethyl methacrylate (a4) 26.7 parts Titanium tetrabutoxide (catalyst) 0.05 parts p-methoxy Phenol (polymerization inhibitor) 0.05 parts

Next, after replacing the air in the reaction vessel with nitrogen gas, nitrogen and air were introduced so that the oxygen concentration became about 10% while stirring, the temperature was raised to 85 ° C., and the temperature was raised to 5 to 10 Torr. The condensation reaction was carried out for 6 hours while releasing the desired water out of the reaction system. Then, vacuum distillation was carried out for 3 hours to remove unreacted compounds. Then, the mixture was cooled to room temperature to obtain the compound (a1) shown in Table 1 having a solution viscosity (Vis) of 15 mPa · s (25 ° C.) and an acid value (AV) of 3.5 mgKOH / g in a colorless and transparent liquid appearance. .. ^{1 1} H-NMR measurement was performed, and it was confirmed that the target product was produced.

(Synthesis Examples 2 to 8) First Method By reacting in the same manner as in Synthesis Example 1 except that the types and amounts of the compounds constituting the compound (a1) were changed according to Table 1, each of Synthesis Examples 2 to 8 Eight compounds were synthesized. Of these, the compound obtained in Synthesis Example 8 is a compound (for comparative examples) that is not compound (a1). The liquid appearance, solution viscosity (Vis) and acid value (AV) of the obtained compound were determined according to the methods described below, and the results are shown in Table 1.

(Synthesis Examples 9 to 12) First Method Compounds of Synthesis Examples 9 to 12, respectively, in the same manner as in Synthesis Example 1 except that the types and amounts of the compounds constituting the compound (a1) were changed according to Table 1. Manufactured. Of these, the compound obtained in Synthesis Example 12 is a compound (for comparative examples) that is not compound (a1).

(Synthesis Example 13) Third Method The following compounds, catalysts and polymerization inhibitors are placed in the reaction tank of a reactor equipped with a reaction tank, a stirrer, a thermometer, a reflux condenser, a nitrogen introduction pipe and an air introduction pipe, respectively. It was prepared in proportion.

[Reaction tank]
Mequinoloxyethyl acid phosphate (a7) 42.9 parts 2-ethylhexyl glycidyl ether (a1-4) 57.1 parts Triethylamine (catalyst) 0.05 parts p-methoxyphenol (polymerization inhibitor) 0.05 parts

Next, after replacing the air in the reaction vessel with nitrogen gas, nitrogen and air were introduced with stirring so that the oxygen concentration became about 10%, the temperature was raised to 85 ° C., and 0.05 part of triethylamine was used as a catalyst. Was added, and a ring-opening addition reaction was carried out for 6 hours. Then, vacuum distillation was carried out for 3 hours to remove unreacted compounds. Then, the mixture was cooled to room temperature to obtain the compound (a1) shown in Table 1 having a solution viscosity (Vis) of 140 mPa · s (25 ° C.) and an acid value (AV) of 10.5 mgKOH / g in a pale yellow transparent liquid appearance. It was. ^{1 1} H-NMR measurement was performed, and it was confirmed that the target product was produced.

(Synthesis Examples 14 to 17) Third Method By reacting in the same manner as in Synthesis Example 13 except that the types and amounts of the compounds constituting the compound (a1) were changed according to Table 1, each of Synthesis Examples 14 to 17 17 compounds were synthesized. Of these, the compound obtained in Synthesis Example 17 is a compound (for comparative examples) that is not compound (a1). The liquid appearance, solution viscosity (Vis) and acid value (AV) of the obtained compound were determined according to the methods described below, and the results are shown in Table 1.

(Synthesis Examples 18 to 30) Third Method Compounds of Synthesis Examples 18 to 30, respectively, in the same manner as in Synthesis Example 13, except that the types and amounts of the compounds constituting the compound (a1) were changed according to Table 1. Manufactured. Of these, the compound obtained in Synthesis Example 21 is a compound (for comparative examples) that is not compound (a1).

(Synthesis Example 31) Second Method The following compounds, catalysts and polymerization inhibitors are placed in the reaction tank of a reactor equipped with a reaction tank, a stirrer, a thermometer, a reflux condenser, a nitrogen introduction pipe and an air introduction pipe, respectively. It was prepared in proportion.

[Reaction tank]
Mequinolyloxyethyl acid phosphate (a7) 44.8 parts Lauryl alcohol (a1-2) 26.5 parts Cetyl alcohol (a1-2) 28.7 parts Titanium tetrabutoxide (catalyst) 0.05 parts p-methoxyphenol (polymerization) Prohibition agent) 0.05 copies

Next, after replacing the air in the reaction vessel with nitrogen gas, nitrogen and air were introduced so that the oxygen concentration became about 10% while stirring, the temperature was raised to 85 ° C., and the temperature was raised to 5 to 10 Torr. The condensation reaction was carried out for 6 hours while releasing the desired water out of the reaction system. Then, vacuum distillation was carried out for 3 hours to remove unreacted compounds. Then, the mixture was cooled to room temperature to obtain the compound (a1) shown in Table 1 having a solution viscosity (Vis) of 86 mPa · s (25 ° C.) and an acid value (AV) of 17.9 mgKOH / g in a colorless and transparent liquid appearance. .. ^{1 1} H-NMR measurement was performed, and it was confirmed that the target product was produced.

(Synthesis Example 32) Second Method The compound of Synthesis Example 32 was produced in the same manner as in Synthesis Example 31 except that the types and amounts of the compounds constituting the compound (a1) were changed according to Table 1.

(Synthesis Example 33) Combination of Second Method and Third Method The following compounds, catalysts and the following compounds, catalysts and The polymerization inhibitors were charged in the following ratios.

[Reaction tank]
Mequinolyloxyethyl acid phosphate (a7) 44.2 parts Lauryl alcohol (a1-2) 34.9 parts Titanium tetrabutoxide (catalyst) 0.05 parts p-methoxyphenol (polymerization inhibitor) 0.05 parts

Next, after replacing the air in the reaction vessel with nitrogen gas, nitrogen and air were introduced so that the oxygen concentration became about 10% while stirring, the temperature was raised to 85 ° C., and the temperature was raised to 5 to 10 Torr. The condensation reaction was carried out for 6 hours while releasing the desired water out of the reaction system. Then, 20.9 parts of cetyl glycidyl ether (a1-4) and 0.05 part of triethylamine as a catalyst were added, and a ring-opening addition reaction was carried out for 6 hours. Then, vacuum distillation was carried out for 3 hours to remove unreacted compounds. Then, the mixture was cooled to room temperature to obtain the compound (a1) shown in Table 1 having a solution viscosity (Vis) of 125 mPa · s (25 ° C.) and an acid value (AV) of 24.8 mgKOH / g in a pale yellow transparent liquid appearance. It was. ^{1 1} H-NMR measurement was performed, and it was confirmed that the target product was produced.

《Liquid appearance》
The liquid appearances of the compounds (a1) (for Examples) and the compounds not compound (a1) (for Comparative Examples) obtained in Synthesis Examples 1 to 33 were visually observed under the conditions of 25 ° C., respectively. It is good if it is not extremely blackish.

<< Liquid Viscosity (Vis) >>
Compounds (a1) (for Examples) and compounds other than Compound (a1) (for Comparative Examples) obtained in Synthesis Examples 1 to 33 were placed in a B-type viscometer (TV- manufactured by Toki Sangyo Co., Ltd.) at 25 ° C. In 22), the measurement was performed under the conditions of rotor Nos. 2 to 4, rotation speed of 0.5 to 100 rpm, and rotation for 1 minute, and the viscosity of the liquid was determined to be (mPa · s).

《Acid value (AV)》
For the compound (a1) (for Examples) and the compound not compound (a1) (for Comparative Example) obtained in Synthesis Examples 1 to 33, about 1 g of a sample was precisely weighed in a stoppered Erlenmeyer flask, and toluene / 100 ml of a mixed solution of ethanol (volume ratio: toluene / ethanol = 2/1) was added and dissolved. A phenolphthalein test solution was added as an indicator, held for 30 seconds, and then titrated with a 0.1 N alcoholic potassium hydroxide solution until the solution turned pink.
The acid value was calculated by the following formula. The acid value was taken as the value of the dry state of the resin (unit: mgKOH / g).
Acid value (mgKOH / g) = {(5.611 × a × F) / S}
However, S: sample collection amount (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
F: Titer of 0.1N alcoholic potassium hydroxide solution

The abbreviations of the materials used in Synthesis Examples 1-33 are shown below. Unless otherwise specified, the numerical values in the table represent parts, blanks indicate no compounding, and "-" indicates unevaluated.

<Abbreviations in Table 1>
-Compound (a1-1)
OPA: orthophosphoric acid, PPA: polyphosphoric acid-Compound (a1-2)
EHOH: 2-ethylhexyl alcohol, LAOH: lauryl alcohol, CEOH: cetyl alcohol ・ Aromatic OH (alcohol with aromatic ring)
BZOH: Benzyl alcohol compound (a1-3)
EHEO: Polyoxyethylene (EO = 18) 2-ethylhexyl ether, LAEO: Polyoxyethylene (EO = 15) lauryl ether, LAPO: Polyoxyepylene (PO = 10) lauryl ether ・ Aromatic EOOH (having an aromatic ring) Polyoxyethylene phenyl ether)
NPEO: Polyoxyethylene (EO = 9) nonylphenol ether compound (a1-4)
EHGE: 2-ethylhexyl glycidyl ether, CEGE: cetyl glycidyl ether, EHOX: 2-ethylhexyl (3-ethyl-3-oxetanyl methyl) ether: LAOX: lauryl (3-ethyl-3-oxetanyl methyl) ether ・ Aromatic Ep ( Glycidyl ether with an aromatic ring)
BPGE: p-tert-butylphenylglycidyl ether compound (a1-5)
LEOG: Lauryl alcohol polyoxyethylene (EO = 15) glycidyl ether, OEOG: 2-ethylhexyl alcohol polyoxypropylene (PO = 10) glycidyl ether, OEOX: 2-ethylhexyl alcohol polyoxyethylene (EO = 10) (3-ethyl) -3-oxetanylmethyl) ether ・ Aromatic EOEP (polyoxyethylene phenylglycidyl ether having an aromatic ring)
PEOG: Phenol polyoxyethylene (EO = 5) glycidyl ether compound (a4)
HEMA: 2-hydroxyethyl methacrylate, 4HBA: 4-hydroxybutyl acrylate compound (a7)
PEMA: Methacryloyloxyethyl acid phosphate, PBA
Acryloyloxybutyl acid phosphate ・ Catalyst TBT: Titanium tetrabutoxide, TEA: Triethylamine ・ Polymerization inhibitor MEQ: p-methoxyphenol

<Water-dispersible polymer (A)>
(Synthesis Example 101)
The following ethylenically unsaturated compounds, surfactants and ion-exchanged water were charged into the stirring tank of a stirring device equipped with a stirring tank, a stirrer and a thermometer at the following ratios.

[Stirring tank]
Ethylene unsaturated compound of Synthesis Example 1 (a1) 0.68 part Acrylic acid (a2) 1.00 part 2-ethylhexyl acrylate (a3) 96.52 part 2-hydroxyethyl methacrylate (a4) 1.45 Part 2-acetoacetoxyethyl methacrylate (a5) 0.36 part KH10 (surfactant) 1.00 part Ion-exchanged water 41.32 part

The above compounds were mixed while stirring the inside of the stirring tank to obtain a pre-emulsified product. Next, the pre-emulsified product of the above compound, the polymerization initiator and the ion-exchanged water are added to the reaction tank and the dropping device of the polymerization reaction device provided with the polymerization tank, the stirrer, the thermometer, the reflux condenser, the dropping device and the nitrogen introduction tube. Each was prepared in the following ratio.

[Polymerization tank]
41.32 parts of ion-exchanged water
[Dripping device]
Pre-emulsified product of the above monomer 141.32 parts 10% potassium persulfate aqueous solution (polymerization initiator) 0.30 parts

After replacing the air in the polymerization tank with nitrogen gas, the temperature was raised to 80 ° C. with stirring under a nitrogen atmosphere, and 0.10 part of a 10% potassium persulfate aqueous solution was added.
After 5 minutes, a mixed solution of the pre-emulsified product of the monomer and a 10% aqueous potassium persulfate solution was added dropwise from the dropping device over 3 hours.
While maintaining the reaction temperature at 80 ° C., while further stirring, a 10% potassium persulfate aqueous solution was added twice every 0.5 hours after completion of the dropwise addition, and then aged for 2 hours to continue the reaction. did. Then, the mixture was cooled to 25 ° C. to obtain an aqueous dispersion of the water-dispersible polymer (A) having a non-volatile content concentration of about 55%. At this time, the filterability and the pot stainability were evaluated as productivity according to the method described later, and the results are shown in Table 2.
Further, the non-volatile content concentration (NV), solution viscosity (Vis), average particle size (Dm), acid value (AV) and glass transition temperature (Tg) of the obtained aqueous dispersion were determined according to the method described below, and the results were obtained. Is shown in Table 2.

(Synthesis Examples 102 to 180)
Aqueous dispersions of water-dispersible polymers were synthesized in the same manner as in Synthesis Example 101, except that the materials and blending amounts shown in Table 2 were changed. Unless otherwise specified, the numerical values shown in Table 2 represent "parts", and blanks indicate that they are not used.
Of these, the aqueous dispersions obtained in Synthesis Examples 108, 112, 117, 121, 140, 141, 147, 162, 163, 171 and 175-177 are not aqueous dispersions (A) but aqueous dispersions. Is.
Further, the aqueous dispersions obtained in 101-107, 109-111, 113-116, 118-120, 122-139, 142-161, 164-170, 172-174 and 178-180 are water-dispersible polymers. The aqueous dispersion of (A). Further, in Synthesis Example 163, a large amount of agglomerates were generated and filtration was impossible.

The mass described in the column of the polymerization initiator in Table 2 means the total mass added in the polymerization tank, the total mass dropped during the dropping, and the post-addition means the total mass added twice after the completion of the dropping. To do.
In addition, the surfactant represents the mass of the aqueous solution in which the non-volatile content concentration is a constant ratio.

<< Evaluation of filterability >>
The aqueous dispersion of the water-dispersible polymer obtained in Synthesis Examples 101 to 180 was filtered through a 180-mesh furnace cloth and evaluated in three stages. In the case of "○" or "△" evaluation, there is no problem in actual use.
◯: Can be filtered quickly and has no residue. Good.
Δ: It takes some time for filtration, and some residue remains to the extent that it does not affect the non-volatile content concentration. Can be used practically.
X: Filtration time is long and there is a considerable amount of residue. The non-volatile content concentration is decreasing. Not practical.

《Evaluation of pot stains》
The state of solid matter adhering to the wall of the polymerization tank after the production of the aqueous dispersion of the water-dispersible polymer obtained in Synthesis Examples 101 to 180 and the detergency with water were evaluated in three stages. In the case of "○" or "△" evaluation, there is no problem in actual use.

◯: No adhesion at all and good detergency Δ: There is some adhesion of solid matter, but the detergency is good. Can be used practically.
X: There is a lot of solid matter adhering, and it cannot be removed by washing. Not practical.

<< Non-volatile component concentration (NV) >>
Approximately 1 g of the aqueous dispersion of the water-dispersible polymer obtained in Synthesis Examples 101 to 180 was weighed in a metal container, dried in an oven at 150 ° C. for 20 minutes, and the residue was weighed to calculate the residual ratio. The non-volatile content concentration (solid content) was used (unit:%).

<< Liquid Viscosity (Vis) >>
The aqueous dispersions of the water-dispersible polymers obtained in Synthesis Examples 101 to 180 were each subjected to a B-type viscometer (TV-22 manufactured by Toki Sangyo Co., Ltd.) at 25 ° C., rotor Nos. 2-4, rotation speed 0. The viscosity of the liquid (mPa · s) was measured under the conditions of rotation at 5 to 100 rpm for 1 minute.

《Acid value (AV)》
With respect to the aqueous dispersion of the water-dispersible polymer obtained in Synthesis Examples 101 to 180, approximately 1 g of a sample was precisely weighed in an Erlenmeyer flask with a stopper, and toluene / ethanol (volume ratio: toluene / ethanol = 2/1). 100 ml of the mixed solution was added and dissolved. A phenolphthalein test solution was added as an indicator, held for 30 seconds, and then titrated with a 0.1 N alcoholic potassium hydroxide solution until the solution turned pink.
The acid value was calculated by the following formula. The acid value was taken as the value of the dry state of the resin (unit: mgKOH / g).
Acid value (mgKOH / g) = {(5.611 × a × F) / S}
However, S: sample collection amount (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
F: Titer of 0.1N alcoholic potassium hydroxide solution

<< Average particle size (Dm) >>
The average particle size of the water-dispersible polymer obtained in Synthesis Examples 101 to 180 in the aqueous dispersion was measured using "Microtrac" manufactured by Nikkiso Co., Ltd. For the average particle size, a value of 50% of the cumulative percentage was applied.

<< Hydrogen ion index (pH) >>
The pH of the aqueous dispersion of the water-dispersible polymer obtained in Synthesis Examples 101 to 180 was measured using F-52S manufactured by HORIBA, electrode: model 6377-10D.

<< Glass transition temperature (Tg) >>
The glass transition temperature (Tg) of the water-dispersible polymer obtained in Synthesis Examples 101 to 180 was determined by using a robot DSC (differential scanning calorimeter, "RDC220" manufactured by Seiko Instruments) and "SSC5200 Disk Station" (manufactured by Seiko Instruments). ) Was connected and measured. Approximately 10 mg of the sample is placed in an aluminum pan, weighed and set in a differential scanning calorimeter, and the same type of aluminum pan without the sample is used as a reference, held at a temperature of 100 ° C. for 5 minutes, and then liquid nitrogen is used. It was rapidly cooled to 120 ° C. Then, the temperature was raised at a heating rate of 10 ° C./min, and the glass transition temperature (Tg, unit: ° C.) was determined from the obtained DSC chart.

<Abbreviations in Table 2>
-Compound (a1)
Synthesis example: Compounds (a1) obtained in each synthesis example shown in Table 1 (Synthesis Examples 1-33)
-Compound (a2)
AA: Acrylic acid, MAA: Methacrylic acid-Compound (a3)
2EHA: 2-ethylhexyl acrylate, LMA: lauryl methacrylate, CEA: cetyl acrylate, ISTA: isostearyl acrylate, BEA: behenyl acrylate, OVE: n-octyl vinyl ether compound (a4)
HEMA: 2-hydroxyethyl methacrylate, 4HBA: 4-hydroxybutyl acrylate compound (a5)
AAEM: 2-acetoacetoxyethyl methacrylate, DAAM: diacetone acrylamide
-Compound (a6)
MMA: Methyl methacrylate, BA: Butyl acrylate, PHEA: Phenoxyethyl acrylate, PEMA: Methacryloyloxyethyl acid phosphate, DPPM: Methacryloyloxyethyl diphenyl phosphate-Surfactant
KH10: Anionic Reactive Surfactant Polyoxyethylene-1- (allyloxyethyl) Alkyl Ether Ammonium Sulfate ["Aqualon KH-10" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] Non-volatile content concentration: 99%, PD104: Anionic reactive Surfactant Polyoxyethylene alkyl alkenyl ether ammonium sulfate [Kao's "Latemuru PD-104"] Non-volatile content concentration: 20%, MS60: Anionic reactive surfactant Methylenebis polyoxyethylene alkyl phenylalkenyl ether ammonium sulfate [Japan Emulsifier "Antox MS-60"] Non-volatile content concentration: 90%, ER20: Nonionic reactive surfactant Allyloxymethylalkoxyethyl hydroxypolyoxyethylene [Adeca "Adecaria Soap ER-20"] Non-volatile Mineral concentration: 75%, WX: Anionic non-reactive surfactant Polyoxyethylene alkyl ether sodium sulfate [Kao's "Latemuru WX"] Non-volatile content concentration: 26%
・ Polymerization initiator
APS: 10% ammonium persulfate aqueous solution
·water
W: Ion-exchanged water

<Water-based pressure-sensitive adhesive>
Using the aqueous dispersions of the water-dispersible polymers obtained in Synthesis Examples 101 to 180, aqueous pressure-sensitive adhesives were prepared by the following methods.
(Example 1)
The following water-dispersible polymer (A), reactive compound (C) and other compound (F) {viscosity modifier, defoaming agent, preservative in the stirring tank of a stirring device equipped with a stirring tank, a stirrer, and a thermometer. And additives} were charged in the following ratios (both are non-volatile components).

[Stirring tank]
Water-dispersible polymer (A) of Synthesis Example 101 100 parts 15% aqueous solution of adipic acid dihydrazide (c1) 0.5 parts Adecanol UH-420 (viscosity adjuster) 0.4 parts SN deformer 154 (antifoaming agent) 0 .3 parts Deltop 100N (preservative) 0.05 parts

A homomixer [“LZB46-HM-3” manufactured by Chuo Rika Co., Ltd.] was used as a stirrer, and the mixture was stirred at a rotation speed of 2,000 rpm for 0.5 hours. Next, while stirring, Acrysol ASE-60 (viscosity adjuster), aqueous ammonia and ion-exchanged water were added for adjustment to obtain a water-based pressure-sensitive adhesive. The non-volatile content concentration (NV), solution viscosity (Vis), hydrogen ion index (pH) and gel fraction (Gel%) of the obtained water-based pressure-sensitive adhesive were determined according to the above method, and the results are shown in Table 3. It was.

(Examples 2 to 81, Comparative Examples 1 to 11, Reference Examples 1 to 3)
Among the materials listed in Table 3, the water-dispersible polymer (A), the reactive compound (C), the viscosity modifier, the defoaming agent, the preservative and the plasticizer are blended according to the description in Table 3 and stirred and mixed. , Each obtained a water-based pressure-sensitive adhesive.
Each of the obtained water-based pressure-sensitive adhesives was applied to each base material, dried and bonded to prepare an adhesive sheet, which was evaluated by the following method. The results of each are shown in Table 4. In Comparative Example 7, since the filterability of the water-dispersible polymer was extremely poor, the water-based pressure-sensitive adhesive was not produced or coated.
In Reference Examples 1 to 3, the effect of adding the plasticizer and the phosphoric acid ester described in Patent Document 1 was evaluated.
The numerical values of the water-dispersible polymer (A), the reactive compound (C) and the other compound (F) shown in Table 3 represent the non-volatile content, and the blanks indicate that they are not used.

<< Non-volatile component concentration (NV) >>
About 1 g of the water-based pressure-sensitive adhesive obtained in each Example, Comparative Example and Reference Example is weighed in a metal container in the same manner as above, dried in an oven at 150 ° C. for 20 minutes, and the balance is weighed and left. The rate was calculated and used as the non-volatile content concentration (solid content) (unit:%).

<< Liquid Viscosity (Vis) >>
Rotate the water-based pressure-sensitive adhesives obtained in the Examples, Comparative Examples, and Reference Examples at 25 ° C. with a B-type viscometer (TV-22 manufactured by Toki Sangyo Co., Ltd.) in the same manner as above. The viscosity of the liquid (mPa · s) was measured under the conditions of a speed of 0.5 to 100 rpm and a rotation of 1 minute.

<< Hydrogen ion index (pH) >>
The pH of the water-based pressure-sensitive adhesives obtained in each Example, Comparative Example and Reference Example was measured using F-52S manufactured by HORIBA and an electrode: model 6377-10D in the same manner as described above.

《Gel%》
The water-based pressure-sensitive adhesives obtained in each Example, Comparative Example and Reference Example were dried on a release liner (a 38 μm-thick release-treated polyethylene terephthalate film, Therapy MF: manufactured by Toray Film Processing Co., Ltd.). The adhesive layer was formed by coating so as to have a thickness of 20 μm and drying with hot air at 100 ° C. for 2 minutes. Next, a 50 μm-thick polyethylene terephthalate film (PET film) was attached to the adhesive layer to prepare an adhesive sheet composed of a 50 μm-thick PET film / adhesive layer / release liner.
Each of the prepared adhesive sheets was cured in an environment of 23 ° C. and 50% relative humidity for 1 day. Then, the adhesive layer is cut into a width of 100 mm and a length of 200 mm, the peeling liner is peeled off from the end of the adhesive sheet, and the surface of the adhesive layer is wrapped with a pre-weighed 200 mesh stainless steel net, which is then contained in ethyl acetate. After immersing at 23 ° C. for 72 hours, it was dried to remove the solvent. Then, the ratio of the mass of the dry coating film after immersion to the mass of the dry coating film before immersion was calculated as the gel fraction, and the ratio of the insoluble matter was defined as the gel fraction (Gel%) and evaluated in three stages. In the case of "○" or "△" evaluation, there is no problem in actual use.
◯: The gel fraction is in the range of 90% or more and 95% or less. Good.
Δ: The gel fraction is in the range of 85% or more and less than 90%. Can be used practically.
X: The gel fraction is less than 85% or more than 95%. Not practical.
Here, the gel fraction (Gel%) was calculated by the following method.
(Gel%) = (mass of dry coating film after immersion-mass of PET film) / (mass of dry coating film before immersion-mass of PET film) × 100

<< Evaluation of storage stability >>
The water-based pressure-sensitive adhesives obtained in each Example, Comparative Example, and Reference Example were collected in a 225 ml mayonnaise bottle in the same manner as above, stored at 25 ° C. for 1 month with a lid, and then water-based pressure-sensitive type. The state of separation between the dispersoid of the adhesive and the liquid layer (dispersion medium) was evaluated on a three-point scale. In the case of "○" or "△" evaluation, there is no problem in actual use.
◯: The aqueous dispersion does not separate even after storage for 1 month. Good.
Δ: It separates after storage for 2 weeks or more, but returns to a uniform aqueous dispersion by shaking. Can be used practically.
X: Separation after storage for less than 2 weeks or shaking does not return to a uniform aqueous dispersion. Not practical.

<< Evaluation of mechanical stability >>
50 g of the water-based pressure-sensitive adhesive obtained in each Example, Comparative Example and Reference Example was collected, 5 g of water was added to dilute the adhesive, and the mixture was filtered through a 300 mesh wire mesh, and 50 g of the adhesive was used as a test sample. And said. Using a marron type mechanical stability tester [manufactured by Tester Sangyo Co., Ltd.], a mechanical load is applied for 10 minutes under the conditions of a temperature of 25 ° C., a load of 15 kg, and a rotation speed of 1,000 rpm, and then 300 mesh of agglomerates are formed. The dry mass of the agglomerates was calculated with respect to the dry mass of the initial water-based pressure-sensitive adhesive, and the mechanical stability was evaluated in three stages based on the agglomerate formation ratio (%). In the case of "○" or "△" evaluation, there is no problem in actual use.
◯: The agglutination ratio is less than 0.1%. Good.
Δ: The agglutination ratio is in the range of 0.1 to 1.0%. Can be used practically.
X: The agglutination ratio exceeds 1.0%. Not practical.
Here, the agglutination ratio was calculated by the following method.
Agglutination rate (%) = 100 x (mass of agglomerates) / (mass of initial test sample)

<< Evaluation of coatability >>
The obtained water-based pressure-sensitive adhesive is placed on a commercially available glassine paper (hereinafter, also referred to as “glassine separator”) that has been peeled off as a peeling liner so that the thickness of the adhesive layer after drying is 18 μm. The adhesive layer was formed by coating and drying with hot air at 100 ° C. for 2 minutes. Next, a commercially available high-quality paper having a thickness of 60 μm was bonded to the coated surface to prepare an adhesive sheet composed of high-quality paper / adhesive layer / release liner. Then, the state of the adhesive layer surface (coated surface) after the peeling liner was peeled off was visually observed and evaluated in three stages. In the case of "○" or "△" evaluation, there is no problem in actual use.
◯: The coated surface is smooth with no repellency, foaming or streaks. Good.
Δ: Some cissing and foaming are observed at the edge of the coated surface. Can be used practically.
X: Repellent, foaming and streaks were observed on the entire coated surface. Bad.

<< Evaluation of workability >>
Each adhesive sheet prepared by the same method as the above << Evaluation of coatability >> was cured in an environment of 23 ° C. and a relative humidity of 50% for 3 days. After that, it was cut into a width of 100 mm and a length of 100 mm, 20 sheets were stacked, and the adhesive layer was projected from the edge of the adhesive sheet when pressed at ^{40 ° C.-60 kg / cm 2 for 1 hour as follows.} Was evaluated on a three-point scale. In the case of "○" or "△" evaluation, there is no problem in actual use.
◯: No protrusion of the adhesive layer is observed. Good.
Δ: Extrusion of the adhesive layer of less than 0.3 mm is observed, but it can be used practically.
X: Extrusion of the adhesive layer of 0.3 mm or more is observed. Bad.

<< Measurement of peel strength >>
Each adhesive sheet prepared by the same method as the above << Evaluation of coatability >> was cut into a width of 25 mm and a length of 100 mm, the release liner was peeled off, and the exposed adhesive layer was polished to a surface of 3 mm in thickness. It was attached to a steel sheet in an environment of 23 ° C. and a relative humidity of 50%, and a roll having a mass of 2 kg was reciprocated once to obtain a measurement sample. Immediately after that, the adhesive strength was measured in the same environment using a tensile tester (Orientec's "Tencilon") under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 degrees (immediately after bonding). Peeling strength measurement).
Further, in the same manner as described above, after leaving this measurement sample in an environment of 23 ° C. and a relative humidity of 50% for 1 day, the peel strength was measured under the same conditions under the same environment (peeling strength measurement 1 day after bonding).
Further, the measurement sample was left in an environment of 70 ° C. for 72 hours and then left in an environment of 23 ° C. and a relative humidity of 50% for 1 hour, and the peel strength was measured by the same method (heating time 72). Peeling strength measurement after time). This peeling strength was evaluated as an adhesive force on a three-point scale. In the case of "○" or "△" evaluation, there is no problem in actual use.
◯: Adhesive strength is within 5.0 to 8.0 (N / 25 mm). Good.
Δ: Adhesive strength is 3.0 (N / 25 mm) or more and less than 5.0 (mN / 25 mm),
Or, it exceeds 8.0 (N / 25 mm) and is less than 10.0 (mN / 25 mm). Practical use is possible.
X: Adhesive strength is less than 3.0 (N / 25 mm) or 10.0 (N / 25 mm) or more. It is defective and cannot be used practically.

<< Evaluation of high-temperature removability >>
Each adhesive sheet prepared by the same method as the above << Evaluation of coatability >> was cut into a width of 25 mm and a length of 100 mm, the release liner was peeled off, and the exposed adhesive layer was polished to a surface of 3 mm in thickness. It was attached to a steel sheet in an environment of 23 ° C. and a relative humidity of 50%, and a roll having a mass of 2 kg was reciprocated once to obtain a measurement sample.
Next, this measurement sample was left to stand for 24 hours in an atmosphere of 120 ° C., left for 1 hour in the same environment, and then peeled off under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 degrees using a tensile tester. The contamination of the surface of the stainless steel sheet after peeling was visually evaluated on a three-point scale. In the case of "○" or "△" evaluation, there is no problem in actual use.
◯: There is no breakage of the base material, and almost no contamination can be confirmed on the stainless steel plate. Good.
Δ: There was no breakage of the base material, but the stainless steel plate was slightly contaminated. Practical use is possible.
X: The base material broke, or significant contamination remained on the stainless steel plate. Not practical.

<< Evaluation of high-speed removability >>
Each adhesive sheet prepared by the same method as the above << Evaluation of coatability >> is cut into a width of 25 mm and a length of 100 mm, the release liner is peeled off, and the exposed adhesive layer is a commercially available veneer plate having a thickness of 3 mm. The sample was attached to the sample in an environment of 23 ° C. and a relative humidity of 50%, and a roll having a mass of 2 kg was reciprocated once to obtain a measurement sample. Next, this measurement sample was left to stand in an atmosphere of 40 ° C. for 78 hours, then left to stand in the same environment for 1 hour, and then peeled off under the conditions of a peeling speed of 1,500 mm / min and a peeling angle of 180 degrees using a tensile tester. Then, the contamination of the veneer plate surface was visually evaluated on a three-point scale. In the case of "○" or "△" evaluation, there is no problem in actual use.
◯: There is no breakage of the base material, and almost no contamination can be confirmed on the veneer plate. Good.
Δ: There was no breakage of the base material, but the veneer plate was slightly contaminated. Practical use is possible.
X: The base material broke, or significant contamination remained on the veneer board. Not practical.

《Measurement of holding power》
Each adhesive sheet prepared by the same method as the above << Evaluation of coatability >> is cut into a width of 25 mm × a length of 100 mm, and the release liner is peeled off so that the bonded portion becomes 25 mm × 25 mm, and the exposed adhesive is used. The layer was attached to a stainless steel (SUS) plate having a thickness of 3 mm in an environment of 23 ° C. and a relative humidity of 50%, and a roll having a mass of 2 kg was reciprocated once to obtain a measurement sample.
After leaving this measurement sample in an environment of 40 ° C. for 20 minutes, a load of 1 kg is applied in an environment of 40 ° C., and a holding force tester [manufactured by Tester Sangyo Co., Ltd.] is used for 70,000 seconds at 40 ° C. The measurement was performed, and the time until the load dropped, or when the load did not drop, the length deviated from the initial pasting was measured and evaluated in the following three stages. In the case of "○" or "△" evaluation, there is no problem in actual use.
◯: There is no drop of load, and the deviation is less than 0.5 mm. Good.
Δ: There is no drop in load, but the deviation is 0.5 mm or more. Practical use is possible.
×: Fall in less than 70,000 seconds. It is defective and cannot be used practically.

<< Evaluation of constant load peelability test >>
Each adhesive sheet prepared by the same method as the above << Evaluation of coatability >> is cut into a width of 10 mm × a length of 100 mm, and the release liner is peeled off so that the bonded portion becomes 10 mm × 80 mm, and the exposed adhesive is used. The layer was attached to a stainless steel (SUS) plate having a thickness of 3 mm in an environment of 23 ° C. and a relative humidity of 50%, and a roll having a mass of 2 kg was reciprocated once to obtain a measurement sample.
The obtained measurement sample was left to stand in an environment of 23 ° C. and a relative humidity of 50% for 24 hours, and then left to stand in an environment of 80 ° C. for 1 hour. Keeping it horizontal, a 50 g weight was hung from the end of the adhesive sheet in the part where it was not attached, left for 10 minutes, and the length of the part peeled off from the stainless steel plate was measured. If all of the stainless steel plate was peeled off within 10 minutes, the time until then was measured and evaluated on a 3-point scale according to the following criteria. The test was conducted in an environment of 80 ° C. In the case of "○" or "△" evaluation, there is no problem in actual use.
◯: Does not fall and has a deviation of less than 20 mm. It is good and there is no problem in practical use.
Δ: Does not fall and has a deviation of 20 mm or more and less than 80 mm. Practical use is possible.
X: Dropped in less than 10 minutes. It is defective and cannot be used practically.

<< Evaluation of curved surface adhesiveness >>
Each adhesive sheet prepared by the same method as the above << Evaluation of coatability >> is cut into a width of 20 mm and a length of 22 mm so that the length direction of the sample is along the circumferential direction on the curved surface of a glass cylinder of 20 mmφ. It was affixed to and crimped with a 2 kg rubber roller, and left for 24 hours in an atmosphere of 23 ° C.-50%. Then, the peeled state of the end portion in the length direction of the sample was visually observed and evaluated in three stages according to the following criteria.
◯: No peeling is performed, or the portion of the sample end less than 0.1 mm is peeled. Good Δ: The portion of 0.1 to 0.5 mm at the end of the sample is peeled off. Practical use is possible.
X: The portion of the sample end exceeding 0.5 mm is peeled off. It is defective and cannot be used practically.

<< Evaluation of substrate adhesion >>
Peel off the release liner from each adhesive sheet created by the same method as << Evaluation of coatability >>, rub the exposed adhesive layer with a finger, and check whether the adhesive layer falls off from the base material, woodfree paper. It was evaluated on a three-point scale based on the following criteria. In the case of "○" or "△" evaluation, there is no problem in actual use.
◯: Does not fall off from the base material even if rubbed more than 15 round trips. It is good and there is no problem in practical use.
Δ: It falls off from the base material after 5 to 15 round trips. Practical use is possible.
X: The pressure-sensitive adhesive falls off in less than 5 round trips. It is defective and cannot be used practically.

The materials used in Examples, Comparative Examples and Reference Examples are shown below. In Tables 3 and 4, blanks mean no compounding, and "-" indicates uncoated.
-Water-dispersible polymer (A)
Synthesis example: Water-dispersible polymer obtained in each synthesis example shown in Table 2 (Synthesis Examples 101-180)
-Reactive compound (C)
ADH: 15% aqueous solution of adipic acid dihydrazide, BOA: 20% methanol solution of orthoboric acid ・ Viscosity adjuster (F)
UH420: "Adecanol UH-420" manufactured by Adeka Corporation, NV = 30%, ASE60: "Acrysol ASE-60" manufactured by Dow Chemical Corporation, NV = 28%
・ Defoamer (F)
SN154: "SN Deformer 154" manufactured by San Nopco
・ Preservative (F)
100N: "Dell Top 100N" manufactured by Osaka Gas Chemical Co., Ltd.
・ Plasticizer (F)
ML240: Polyoxyethylene lauryl ether phosphoric acid [manufactured by Toho Chemical Industry Co., Ltd., trade name "Phosphanol ML-240"]
・ Ammonia water AN: 25% ammonia water ・ Water W: Ion-exchanged water

As described above, the water-based pressure-sensitive adhesive of the present invention has storage stability in Examples 1-31, 33-35, 37-42, 44, 45, 47-55, 57-65 and 67-81. Mechanical stability, coatability, workability, peel strength (immediately after 1 day, after heating 72 hours), re-peelability (high temperature, high speed), holding force, constant load peeling, curved surface adhesiveness and substrate adhesion In any of the above, the "Δ" evaluation (practical level) is 3 or less out of 13 items, and the others are all "○" evaluations (good level), indicating that they are excellent.
Further, in Examples 32, 36, 43, 46, 56 and 66, the “Δ” evaluation (practical level) of each evaluation was 4 to 13 out of 13 items, and the “x” evaluation (defective level) was. Since there is no one, it can be used without any problem in practical use.
On the other hand, in Comparative Examples 1 to 11 and Reference Examples 1 to 3, storage stability, mechanical stability, coatability, workability, peel strength (immediately after 1 day, after heating 72 hours), and re-peeling It can be seen that any of the properties (high temperature, high speed), holding force, constant load peeling, curved surface adhesiveness, and substrate adhesion is extremely inferior.

The water-based pressure-sensitive adhesive according to the present invention has excellent storage stability, mechanical stability, coatability, workability, adhesiveness, re-peelability, curved surface adhesiveness, constant load peelability, substrate adhesion, etc. In addition to the general fields of labels and sheets, the fields of construction (eg, exterior, interior, equipment, etc.), electrical equipment (eg, home appliances, kitchen equipment, air conditioning, etc.), transport equipment (eg, ships, etc.) It can also be used in various industrial fields other than the optical field such as automobiles), furniture fields, and miscellaneous goods fields.

Claims (11)

A structural unit derived from the ethylenically unsaturated compound (a1) represented by the following general formula (1), a structural unit derived from the ethylenically unsaturated compound (a2) having a carboxyl group, and an alkyl group having 4 to 24 carbon atoms. A water-based pressure-sensitive adhesive comprising a water-dispersible polymer (A) having no aromatic ring and containing a structural unit derived from the ethylenically unsaturated compound (a3) having.

(In the formula, n is an integer of 1 to 4. R ₁ is a hydrogen atom or a methyl group. R ₂ and R ₃ are independently hydrogen atoms or hydroxyl groups and / or oxyalkylene groups, respectively. It is an alkyl group that may be substituted. R ₄ is an alkylene group having 2 to 4 carbon atoms. R ₂ and R ₃ are not hydrogen atoms at the same time.) The water-based pressure-sensitive adhesive according to claim 1, wherein R ₂ and R ₃ are independently hydrogen atoms or alkyl groups or groups represented by any of the following general formulas (2) to (4).

(In the formula, m and l are integers of 1 to 20. R ₅ , R ₈ and R ₁₀ are alkyl groups. R ₆ and R ₉ are alkylene groups having 2 to 4 carbon atoms. R ₇ is an alkylidine group.) As the structural unit of the polymer (A), a structural unit derived from the ethylenically unsaturated compound (a4) having a hydroxyl group and / or a structural unit derived from the ethylenically unsaturated compound (a5) having a carbonyl group is further contained. The water-based pressure-sensitive adhesive according to claim 1 or 2, wherein the aqueous pressure-sensitive adhesive is made of. (However, the compound (a4) excludes the compound (a1), and the compound (a5) excludes the compound (a2).) In 100% by mass of the structural unit of the polymer (A),
The compound (a1) 0.1 to 10% by mass,
0.1 to 10% by mass of the compound (a2), and 80 to 99.8% by mass of the compound (a3).
The water-based pressure-sensitive adhesive according to claim 1 or 2. In 100% by mass of the polymer (A),
The compound (a1) 0.1 to 10% by mass,
The compound (a2) 0.1 to 10% by mass,
65-99.78% by mass of the compound (a3),
The compound (a4) 0 to 10% by mass, and the compound (a5) 0 to 5% by mass,
3. The water-based pressure-sensitive adhesive according to claim 3. (However, the total of the compound (a4) and the compound (a5) does not become 0% by mass.) The water-based pressure-sensitive adhesive according to any one of claims 1 to 5, wherein the glass transition temperature of the polymer (A) is in the range of −80 to −10 ° C. The water-based pressure-sensitive adhesive according to any one of claims 1, 2, 3, 5 or 6, further containing a structural unit derived from the reactive surfactant (B) as a structural unit of the polymer (A). .. The aqueous pressure-sensitive adhesive according to claim 7, wherein the reactive surfactant (B) contains an anionic reactive surfactant and / or a nonionic reactive surfactant. The water-based pressure-sensitive adhesive according to any one of claims 1 to 8, further comprising a reactive compound (C) capable of reacting with the polymer (A). (However, the compound (C) excludes the reactive surfactant (B).) The polymer (A) has a hydroxyl group and / or a carbonyl group, and the reactive compound (C) can react with a hydroxyl group and / or a carbonyl group in the polymer (A). The water-based pressure-sensitive adhesive according to claim 9. An adhesive sheet comprising a base material and an adhesive layer formed from the water-based pressure-sensitive adhesive according to any one of claims 1 to 10.