JP2022074246A - Aqueous pressure-sensitive adhesive and adhesive sheet - Google Patents

Abstract

To provide an aqueous pressure-sensitive adhesive with which formation of an adhesive layer, having suppressed lowering of adhesiveness due to degradation of neutral paper, is made possible even when potassium carbonate-containing paper such as neutral paper is used for a base material, and with which an adhesive sheet having releasability after use at high temperature of 100°C or more (hereafter high temperature releasability) and durability made compatible with each other and having suppressed contamination in high speed releasing is obtained.SOLUTION: The problem is solved by using an aqueous pressure-sensitive adhesive: including a water dispersible polymer (A) having a carbonyl group and no carboxy group and a reactive compound (C) having a functional group capable of reacting with a carbonyl group, in which the water dispersible polymer (A) is a copolymer of a mixture including ethylenically unsaturated compounds (a1)-(a3); including 0.01-10 pts.mass of the reactive compound (C) based on the water dispersible polymer (A) of 100 pts.mass; and including no compound having an aromatic ring.SELECTED DRAWING: None

Description

The present invention relates to a 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 liner" (single-sided pressure-sensitive adhesive sheet) or "release liner / adhesive layer / support (release liner / adhesive layer / support). Another name: base sheet) / adhesive layer / release liner ”(double-sided pressure-sensitive adhesive sheet). At the time of use, the release liner 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 material 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 support surface of paper, plastic film, cloth, metal plate, etc., are applied to the adherend surface at room temperature with a pressure of about 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 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, the adhesive tape such as masking tape attached to the adherend for painting and forming the 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 Is very difficult to control. In particular, if the adhesive strength between the adhesive label and the adherend is too high, the pressure-sensitive adhesive remains on the adherend when trying to peel off, or when the support is paper, the support Is destroyed (also known as substrate fracture), so-called paper tearing occurs, making re-peeling difficult. Further, if the adhesive strength 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 adhesion to the adherend or the like is not sufficient, and the purpose originally expected for the adhesive label or the like can be achieved. It will be difficult.

In recent years, in consideration of the protection of the global environment and the working environment, the number of water-based pressure-sensitive adhesives has begun to increase. Among them, a water-based pressure-sensitive adhesive containing an acrylic resin having excellent adhesiveness and weather resistance as a main component (hereinafter, may be simply referred to as an adhesive) has become widespread.
As the surface base material of the water-based pressure-sensitive adhesive, plastic film, synthetic paper, paper, metal foil and the like are used. Among them, adhesive sheets using paper base materials, which are the mainstream, are widely used for distribution management labels for foods and products, address display labels for delivery, raw fabrics for form printing such as copy tables, adhesive tapes, and the like. .. Conventionally, the paper used as the base material of the adhesive sheet has been mainly acid paper made by using aluminum sulfate for fixing the solvent-type rosin sizing agent (hereinafter referred to as acid paper). However, since aluminum sulfate is weakly acidic, there is a problem that cellulose, which is the main component of the fiber, is hydrolyzed and the paper deteriorates over time. Therefore, recently, paper made using a neutral sizing agent such as alkyl ketene dimer (AKD) or alkenyl succinic anhydride (ASA) (hereinafter referred to as acid-free paper) is widely used in consideration of storage stability. ing.
By the way, calcium carbonate has easy control of particle size, particle size distribution and particle shape, high whiteness and opacity, and low cost. However, since it dissolves under acidic conditions, it has not been used for acid paper so far, but in the case of acid-free paper, such calcium carbonate can now be used as a filler.

In addition, in order to raise awareness of environmental issues and protect forest resources in recent years, recycled paper containing used paper as a raw material is widely distributed as printing paper and copying paper. When making these recycled papers, the raw materials for used paper contain a large amount of neutral paper containing calcium carbonate. However, since the above-mentioned calcium carbonate dissolves under acidic conditions, acidic papermaking cannot be performed. Therefore, the papermaking of recycled paper is inevitably neutral papermaking, and the ratio of acid-free paper to the whole paper is increasing.
Even in adhesive sheets, it is inevitable to switch from acid paper to acid-free paper as the surface base material, and in particular, neutral paper, which is recycled paper, can be used as the base material for surface base materials and release liners. It is needed.

However, conventional water-based pressure-sensitive adhesives are contained in the neutral paper or glossy paper containing calcium carbonate when the neutral paper or glossy paper is used as the base material of the surface base material or the release liner. Calcium ions are released from calcium carbonate and undergo a cross-linking reaction with the carboxyl group contained in the pressure-sensitive adhesive. Therefore, over time, such as during storage of the adhesive sheet or after peeling off the release liner and attaching it to the adherend. Therefore, there is a problem that the cohesive force of the adhesive layer is changed, the adhesive force is significantly reduced, and the curved surface adhesiveness is significantly reduced as compared with the case of using acidic paper.
Further, the conventional water-based pressure-sensitive adhesive uses a neutral paper containing calcium carbonate, particularly a neutral paper or glossy paper containing calcium carbonate as a surface base material, under high temperature and high humidity. It appears prominently when left in. Such a phenomenon that adversely affects the adhesiveness of the pressure-sensitive adhesive with acid-free paper is called "acid-free paper deterioration".

In such an environment, various attempts have been made to satisfy the above-mentioned various characteristics.
For example, in an adhesive sheet in which a surface substrate containing a calcium component in a paper layer, an adhesive layer containing an acrylic copolymer as a main component, and a release liner are sequentially laminated, the calcium component in the surface substrate can be used. , An adhesive sheet in which the carboxylic acid component of the acrylic copolymer in the adhesive layer is suppressed from being ionized has been studied. As the ionization suppressing means, specifically, the means shown in the following (1) to (3) and the like are disclosed.
(1) Reduce the carboxyl groups that cause cross-linking as much as possible (see Patent Document 1).
(2) Potassium sulfate, potassium pyrophosphate and the like are contained in the pressure-sensitive adhesive as a source of potassium ions which have a larger ionization tendency than calcium ions and therefore easily react with carboxylic acid than calcium ions.
(3) A chelating agent such as an ammonium salt of EDTA (ethylenediaminetetraacetic acid) is contained in the adhesive.

Further, a block polymer obtained by polymerizing a monomer component having a carboxyl group in the molecule and having a monomer having a glass transition point of a homopolymer having a glass transition temperature of less than 0 ° C. as an essential component, this block polymer. A pressure-sensitive adhesive containing the above is disclosed (see Patent Document 2).

Further, it has 57 to 98.8 parts by weight of a (meth) acrylic acid alkyl ester, 1 to 20 parts by weight of a monomer containing a functional group, and a (meth) acryloyl group, and has a glass transition temperature of 40 ° C. or higher. 0.2 to 3 parts by weight of the macromonomer having a number average molecular weight in the range of 2,000 to 20,000 and 0 to 20 other monomers copolymerizable with at least the (meth) acrylic acid alkyl ester. Disclosed is a pressure-sensitive adhesive for a liquid crystal element, which comprises a copolymer with a weight portion as a main component and has a weight average molecular weight of the copolymer in the range of 500,000 to 2,000,000. See Patent Document 3).

Japanese Unexamined Patent Publication No. 2002-338909 Japanese Patent Application Laid-Open No. 2003-026743 Japanese Unexamined Patent Publication No. 08-209095

The method (1) above is the most direct and effective method, such as the water-based pressure-sensitive adhesive described in Patent Document 1, and the carboxyl group is an adhesive layer in both solvent-based and water-based adhesives. It is a functional group that is indispensable for ensuring the holding power (cohesive power) of the solvent. In particular, when the main component is an aqueous dispersion of a polymer obtained by emulsion-polymerizing a (meth) acrylic compound in an aqueous solution, that is, an aqueous medium, if emulsion polymerization is attempted without using a compound having a carboxyl group at all, polymerization will occur. The stability is extremely poor, and a large amount of agglomerates are generated. Even if the agglomerates are separated, the viscosity of the adhesive changes significantly over time. Furthermore, its performance as an adhesive is extremely insufficient.

Therefore, when an unsaturated compound having a carboxyl group is not used at all, or when a very small amount of at most 1% by weight or less is used, the amount of the polymerization initiator, the amount of the chain transfer agent, etc. are controlled. When the molecular weight of the obtained polymer is reduced, the adhesive has a reduced holding power (aggregating power), so that the adhesive sheet apparently exhibits a certain degree of adhesive strength, but the adhesive sheet has a small holding power (aggregating power). The so-called "glue residue" phenomenon, in which the adhesive layer is transferred to the adherend when the adhesive is peeled off from the adherend, becomes remarkable. That is, the basic performance required for the removable pressure-sensitive adhesive cannot be satisfied.

In this case, when acid-free paper is used as the surface base material, the holding force (cohesive force) becomes significantly larger after storage under high temperature and high humidity than after storage under normal conditions, and on the other hand, the adhesive force is significantly increased. It is extremely difficult to suppress the deterioration of acid-free paper because it is lowered.

Further, in the method of containing potassium sulfate, potassium pyrophosphate, etc. in the adhesive as in the method (2) above, potassium is easier to ionize than calcium, and the generated potassium ion is carboxyl unlike calcium ion. The cross-linking reaction is irreversible because it does not form a cross-linking structure with the group and calcium ions form a sparingly soluble salt with the carboxyl group. Therefore, since cross-linking of calcium ions will eventually occur, it is not an effective means as a countermeasure against deterioration of acid-free paper.

The method (3) above is effective as a countermeasure against acid-free paper deterioration, but on the other hand, when a sequestrant such as EDTA is added to the adhesive, the viscosity of the adhesive decreases and the coatability is low. Not only is it difficult to secure the adhesive layer, but also the adhesion between the pressure-sensitive adhesive layer and the base material is insufficient, and the adherend surface is contaminated with the adherend (cloudiness, glue) derived from the sequestrant. The rest) may be seen.

Further, the pressure-sensitive adhesive described in Patent Document 2 has an effective adhesion even for an adherend having a mirror-processed mirror surface, which is difficult to adhere, and having a small anchoring effect (anchor effect) of the pressure-sensitive adhesive. Moreover, it presents a block polymer having excellent adhesive properties.
The above-mentioned monomer having a glass transition point of less than 0 ° C. is obtained by adding one or more ε-caprolactone to monohydroxyethyl (meth) acrylate succinate or (meth) acrylic acid. Although it is an acrylic acid ester, it has inferior cohesive power under high temperature and high humidity, and has drawbacks such as peeling from the adherend over time. Therefore, the adhesive component has a carboxyl group in the molecule and is a homopolymer. The essential component is a monomer having a glass transition point of less than 0 ° C.
Therefore, when neutral paper or the like is used as the base material, cross-linking of calcium ions is generated, which is not an effective means as a countermeasure against deterioration of the neutral paper.

Further, the pressure-sensitive adhesive described in Patent Document 3 contains a predetermined macromonomer in a predetermined blending ratio, so that the polarizing plate or the like does not swell or peel off, and the polarizing plate or the like is damaged. It is shown that adhesive residue is unlikely to occur on the substrate or the like when it is peeled off. A macromonomer is copolymerized with another monomer to obtain a main agent polymer, and a pressure-sensitive adhesive is obtained using the main agent polymer. However, when used in an aqueous pressure-sensitive adhesive, the molecular weight of the macromonomer is too high. Therefore, the compatibility is poor and phase separation is likely to occur in the adhesive layer. In addition, when a macromonomer is simply incorporated other than emulsion polymerization, it is difficult to control the polymerization, and gelation is likely to occur during the polymerization. In addition, since the cohesive force is high and the adhesive force is high, the adhesiveness is preferable in the liquid crystal element application, but it is difficult to peel off once it is attached, and it is difficult to use it in the normal re-peelable application. In particular, the re-peelability after use at a high temperature of 100 ° C. or higher and the re-peelability at the time of high-speed peeling become insufficient, and adherent contamination such as adhesive residue and fogging is likely to occur.

The problem to be solved by the present invention is that even when a potassium carbonate-containing paper such as acid-free paper is used as a base material, it is possible to form an adhesive layer in which deterioration of adhesiveness due to deterioration of acid-free paper is suppressed. In addition, a water-based feeling that achieves both durability and re-peelability after use at a high temperature of 100 ° C or higher (hereinafter referred to as high-temperature re-peelability) and suppresses contamination in high-speed peeling. It is to provide a pressure adhesive.

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, it contains a water-dispersible polymer (A) having a carbonyl group and no carboxyl group, and a reactive compound (C) having a functional group capable of reacting with the carbonyl group.
The water-dispersible polymer (A) is a copolymer of a mixture containing the following ethylenically unsaturated compounds (a1) to (a3).
A water-based pressure-sensitive adhesive containing 0.01 to 10 parts by mass of the reactive compound (C) with respect to 100 parts by mass of the water-dispersible polymer (A) and not containing a compound having an aromatic ring.
(A1) Ethylene unsaturated compound having an alkyl group having 4 to 24 carbon atoms (a2) Ethylene unsaturated compound having an ester bond (a3) Ethylene unsaturated compound having a carbonyl group (however, an ethylenically unsaturated compound) (A2) is excluded)

The water-based pressure-sensitive adhesive of the present invention makes it possible to manufacture a re-peelable adhesive label having good adhesiveness and re-peelability to various adherends, which could not be realized by the conventional pressure-sensitive adhesive. became. 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.
Further, since the ester bond site in the water-dispersible polymer is oriented at the interface between the adhesive layer and the adherend, the decrease in adhesiveness to calcium carbonate-containing paper such as acid-free paper as a surface base material is suppressed. It has become possible and it has become possible to suppress contamination due to high-speed peeling.

Hereinafter, embodiments of the present invention will be described.
In the present specification, the water-dispersible polymer (A), the reactive compound (C) capable of reacting with the polymer (A), and (a1) an ethylenically unsaturated compound having an alkyl group having 4 to 24 carbon atoms. , (A2) an ethylenically unsaturated compound having an ester bond, (a3) an ethylenically unsaturated compound having a carbonyl group, and (a4) another ethylenically unsaturated compound having no carboxyl group and an aromatic ring. (A), reactive compound (C), ethylenically unsaturated compound (a1), ethylenically unsaturated compound (a2), ethylenically unsaturated compound (a3) and ethylenically unsaturated compound (a4) are abbreviated. There is.

Further, the ethylenically unsaturated compound (a) is a tylene unsaturated compound having no aromatic ring.
Further, the "carbonyl group" in the present specification does not include a carbon-oxygen double bond directly bonded to a carbon-carbon double bond represented by a (meth) acryloyl group or the like. 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. Not included.

In addition, when it is described as "(meth) acrylic", "(meth) acryloyl", "(meth) acrylic acid", "(meth) acrylate", "(meth) acryloyloxy", and "(meth) allyl". Unless otherwise specified, "acrylic or methacrylic", "acryloyl or methacrylic acid", "acrylic acid or methacrylic acid", "acrylate or methacrylate", "acryloyloxy or methacryloyloxy", and "allyl or methacrylic acid", respectively. ".

The mass average molecular weight (Mw) is a polystyrene-equivalent value measured by a gel permeation chromatography (GPC) method. Details of the Mw measurement method are described in Examples.
Unless otherwise noted, the various components mentioned in the present specification may be used independently or in combination of two or more.

≪Water-based pressure-sensitive adhesive≫
First, the water-based pressure-sensitive adhesive will be described.
The aqueous pressure-sensitive adhesive of the present invention contains a water-dispersible polymer (A) having a carbonyl group and no carboxyl group, and a reactive compound (C) having a functional group capable of reacting with the carbonyl group.
The water-dispersible polymer (A) is a copolymer of a mixture containing the following ethylenically unsaturated compounds (a1) to (a3).
The reactive compound (C) is contained in an amount of 0.01 to 10 parts by mass with respect to 100 parts by mass of the water-dispersible polymer (A), and the compound having an aromatic ring is not contained.
(A1) Ethylene unsaturated compound having an alkyl group having 4 to 24 carbon atoms (a2) Ethylene unsaturated compound having an ester bond (a3) Ethylene unsaturated compound having a carbonyl group (however, an ethylenically unsaturated compound) (A2) is excluded)

As described above, by using a water-dispersible polymer having an ester bond site and not containing a compound having an aromatic ring, a re-peelable adhesive label having good adhesiveness and re-peelability to various adherends and the like can be used. It has become possible to manufacture.
Hereinafter, each component constituting the water-based pressure-sensitive adhesive will be specifically described.

<Water-dispersible polymer (A)>
The water-dispersible polymer (A) is an water-dispersible polymer having a carbonyl group and no carboxyl group, and (a1) an ethylenically unsaturated compound having an alkyl group having 4 to 24 carbon atoms, (a1). It is a copolymer of a2) an ethylenically unsaturated compound having an ester bond other than the (meth) acryloyloxy group and (a3) an ethylenically unsaturated compound having a carbonyl group, and does not have an aromatic ring.
That is, the water-dispersible polymer (A) polymerizes a mixture of an ethylenically unsaturated compound (a) having no aromatic ring and a monomer containing a reactive surfactant (B), if necessary. As a result, the ethylenically unsaturated compound (a) is (a1) an ethylenically unsaturated compound having an alkyl group having 4 to 24 carbon atoms, (a2) an ethylenically unsaturated compound having an ester bond, and (a3). It is classified into an ethylenically unsaturated compound having a carbonyl group and (a4) other ethylenically unsaturated compounds having no carboxyl group and an aromatic ring.
Since the water-dispersible polymer (A) does not have an aromatic ring, it is possible to maintain flexibility and curved surface adhesiveness.

<< Ethylene unsaturated compound (a1) >>
The ethylenically unsaturated compound (a1) has an ethylenically unsaturated double bond and a linear or branched alkyl group having 4 to 24 carbon atoms in the molecule, and does not have a carboxyl group and an aromatic ring. Is. Having an alkyl group having 4 to 24 carbon atoms makes it possible to control the flexibility and appropriate adhesiveness of the coating film. However, the cases of compound (a2) and compound (a3) are excluded.
Examples of the ethylenically unsaturated compound (a1) include n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, pentyl acrylate, isoamyl acrylate, hexyl (meth) acrylate, and heptyl (meth) acrylate. , (Meta) 2-ethylhexyl acrylate, (meth) n-octyl acrylate, (meth) isooctyl acrylate, (meth) acrylate 3,4-dimethylhexyl, (meth) nonyl acrylate, (meth) acrylic acid Isononyl, (meth) acrylate 3,4-dimethylheptyl, (meth) acrylate n-decyl, (meth) acrylate isodecil, (meth) acrylate lauryl, (meth) acrylate tridecyl, (meth) acrylate (Meta) acrylic acid alkyl esters such as cetyl, (meth) isostearyl acrylate, (meth) acrylate stearyl, (meth) acrylate behenyl, (meth) acrylate tetracosyl;

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). Examples thereof include alkyl (meth) allyl ethers such as allyl ether and stearyl (meth) allyl ether, 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 (a2) >>
The ethylenically unsaturated compound (a2) is an ethylenically unsaturated compound having an ester bond.
The "ester bond" of the ethylenically unsaturated compound (a2) does not include —C (= O) O— of the (meth) acryloyloxy group. That is, the compound (a2) is a compound having an ester bond other than the acryloyloxy group and an ethylenically unsaturated double bond in its structure, and does not have a carboxyl group and an aromatic ring.
Further, even if it has an alkyl group having 4 to 24 carbon atoms, if it has an ester bond, it corresponds to the ethylenically unsaturated compound (a2).
By using the ethylenically unsaturated compound (a2) as a part of the constituent monomer, the affinity with other compounds constituting the water-dispersible polymer (A) is low, so that the adhesive layer adheres in the adhesive layer. It orients at the interface between the agent layer and the adherend and changes the surface polarity. 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 has a feature that it can be excellent in various performances such as imparting a good texture.

The ethylenically unsaturated compound (a2) is a compound having an ester bond other than the (meth) acryloyloxy group in the molecule, and a cyclic ester is ring-opened and added to the ethylenically unsaturated compound having a hydroxyl group by a known method. , A compound having an ethylenically unsaturated double bond at the molecular end or both ends (a2-1), or by polymerizing any ethylenically unsaturated compound to have an ethylenically unsaturated double bond at the molecular end or both ends. , A comparatively high molecular weight polymerization reactive compound (also known as "macromonomer") (a2-2) and any polyester resin having 1 to 4 ethylenically unsaturated double bonds at the molecular ends. It is classified as a low molecular weight polymerization-reactive compound (also referred to as “polyester acrylate oligomer”) (a2-3).

As the cyclic ester used as a constituent unit of the compound (a2-1), ε-caprolactone or δ-valerolactone is preferably ring-opened and added to the ethylenically unsaturated compound having a hydroxyl group, and ε-caprolactone is ring-opened and added. Is more preferable. The number of added moles to be added by ring opening is preferably 1 to 10 mol, more preferably 1 to 5 mol. Further, on the opposite side of the molecule to which the ethylenically unsaturated double bond is bonded, an ethylenically unsaturated double bond, a hydroxyl group or an alkoxy group having 1 to 4 carbon atoms is preferable, and the ethylenically unsaturated double bond is preferable. The substituent having a double bond is preferably a (meth) acryloyl group. Further, it is not particularly limited as long as it is in the range of the mass average molecular weight (Mw) described later.

As the compound (a2-1), a commercially available product can also be used. For example, unsaturated fatty acid hydroxyalkyl ester-modified ε-caprolactone (product name “Plaxel FA series” manufactured by Daicel), (product name “Plaxel FM series” Daicel). (Manufactured by), (Product name "Aronix M series" manufactured by Toagosei Co., Ltd.) and the like.

Compound (a2-2) is a relatively high molecular weight polymerizable monomer component having an ethylenic double bond at the molecular end or both ends, and has a polymer chain portion and an ethylenic double bond portion. It is a compound which is composed of and does not have a carboxyl group and an aromatic ring.
The manufacturing method is
(1) A method in which a polymer chain (living polymer anion) constituting a macromonomer is produced by living anionic polymerization, and methacrylic acid chloride or the like is allowed to act on the polymer chain (living polymer anion).
(2) In the presence of a chain transfer agent such as mercaptoacetic acid, a radically polymerizable monomer such as methyl methacrylate is polymerized to obtain an oligomer having a carboxyl group at the terminal, which is then reacted with glycidyl methacrylate or the like. Method.
(3) A radically polymerizable monomer such as methyl methacrylate is polymerized in the presence of an azo-based polymerization initiator containing a carboxyl group to obtain an oligomer having a carboxyl group at the terminal, and then macromonomerized with glycidyl methacrylate. Method.
Is a general method, and examples of the substituent having an ethylenically double bond include a vinyl group, a (meth) allyl group, a (meth) acryloyl group, and the like, and a (meth) acryloyl group is preferable.
also,

The polymer chain portion constituting the compound (a2-2) is methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t (meth) acrylate. -The main constituent unit is a repeating unit derived from (meth) acrylic acid alkyl ester such as butyl, 2-ethylhexyl (meth) acrylate, stearyl acrylate, or styrene, acrylonitrile, hydroxy (meth) acrylate, silicone, etc. However, it is preferable that the polymer chain is composed of repeating units of an aliphatic (meth) acrylic acid ester having no aromatic ring. The range of the number of added moles of the repeating unit is preferably 2 to 20 mol, more preferably 2 to 10 mol.
These polymer chain moieties may be composed of a single repeating unit, may be composed of a plurality of repeating units, and may be an alternating copolymer, a random copolymer, or a block copolymer. May be. Further, it is not particularly limited as long as it is in the range of the mass average molecular weight (Mw) described later.

Commercially available products can also be used for the compound (a2-2), for example, a macromonomer having a (meth) acryloyl group at the molecular end and a polymer chain of methyl polymethacrylate (pMMA) (product name "AA-6"). Macromonomer of butylpolyacrylic acid (pBA) (product name "AB-6" manufactured by Toa Synthetic Co., Ltd.), macromonomer of isobutyl polyacrylic acid (piso-BA) Monomers (product name "AW-6" manufactured by Toa Synthetic Co., Ltd.) and the like can be mentioned.

The compound (a2-3) is a low molecular weight polyester obtained by polycondensation of a short chain polyol and a polycarboxylic acid, an ethylenically unsaturated compound having a carboxyl group, an ethylenically unsaturated compound having a hydroxyl group, or an epoxy group. It is a compound that can be obtained by reacting with an ethylenically unsaturated compound that has, does not have a carboxyl group and an aromatic ring in its structure, and does not have a urethane bond.

Known short-chain polyols include, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-. Examples thereof include low molecular weight polyols such as butyl-2-ethyl-1,3-propanediol, trimethylolpropane, glycerin, and pentaerythritol.

Known polycarboxylic acids include, for example, oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, suberic acid, maleic acid, chloromaleic acid, fumaric acid, dodecanedioic acid, pimelic acid, citraconic acid. , Glutalic acid, itaconic acid, succinic anhydride, maleic anhydride and other aliphatic dicarboxylic acids and their anhydrides;
Examples thereof include alicyclic dicarboxylic acids such as dimer acid, hexahydroterephthalic acid, hexahydroisophthalic acid, hexahydrophthalic acid and tetrahydrophthalic acid, and anhydrides thereof.

The low molecular weight polyester resin used as a constituent unit of the compound (a2-3) can be obtained by a polycondensation reaction between the short-chain polyol and the polycarboxylic acid. At this time, the reaction proceeds even without a catalyst, although the reaction proceeds. A catalyst can also be used as appropriate to allow the reaction to proceed more smoothly.
The catalysts used are ammonia, amines, quaternary ammonium salts, quaternary phosphonium salts, alkali metal hydroxides, alkaline earth metal hydroxides, Lewis acids, tin, lead, titanium, iron, zinc, zirconium. , Organic metal compounds containing cobalt and the like, metal halides and the like.

In the low molecular weight polyester resin used as a constituent unit of the compound (a2-3), the molecular weight and the terminal functional group are adjusted by the balance between the amount of hydroxyl groups contained in the short-chain polyol and the amount of carboxyl groups contained in the polycarboxylic acid.
The compound (a2-3) is first polycondensed with the short-chain polyol and the polycarboxylic acid by a known method to obtain a low molecular weight polyester. At this time, the molecular weight and the terminal functional group are adjusted by the balance between the amount of the carboxyl group contained in the polycarboxylic acid and the amount of the hydroxyl group of the short-chain polyol. When adjusted to be An acrylate oligomer) can be obtained.

Examples of the ethylenically unsaturated compound having a carboxyl group include (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, and anhydrous itaconic acid half-esterified with an alkyl alcohol, and two amounts of acrylic acid. The body etc. can be mentioned. The ethylenically unsaturated compound having a carboxyl group is not included in the ethylenically unsaturated compound (a) and the ethylenically unsaturated compound corresponding to the other ethylenically unsaturated compound (a4) described later.

When the terminal functional group is a hydroxyl group, a commercially available product can be used as the low molecular weight polyester, for example, polyester polyol (product name "Polylite series" manufactured by DIC), (product name "ETERNACOLL series" manufactured by Ube Kosan Co., Ltd.). , (Product name "Kuraray Polyester P Series" manufactured by Kuraray), (Product name "Kuraray Polyol N Series" manufactured by Kuraray), (Product name "UNIC Series" manufactured by Itoh Oil Chemicals), (Product Name "PLACCEL Series" Dycel (Product name "Kyowa Pole Series" manufactured by Kyowa Hakko Chemical Co., Ltd.), (Product name "Plaxel Series" manufactured by Daicel Co., Ltd.) and the like. Each of these may be used alone or in combination of two or more.

Further, in the case of "amount of carboxyl group contained in polycarboxylic acid> amount of hydroxyl group contained in short chain polyol", the terminal functional group becomes a carboxyl group, and a carboxyl group of an ethylenically unsaturated compound having a hydroxyl group is added thereto. The target compound (a2-3) (polyester acrylate oligomer) can be obtained by subjecting it to a condensation reaction or by subjecting it to an addition reaction with an epoxy group of an ethylenically unsaturated compound having an epoxy group.

The ethylenically unsaturated compound having an epoxy group, which is a constituent unit constituting the ethylenically unsaturated compound (a2-3), is one of the ethylenically unsaturated compounds corresponding to the other ethylenically unsaturated compounds (a4) described later. It is a compound which has an epoxy group and a substituent having an ethylenically unsaturated double bond in its structure and does not have an aromatic ring.
Examples of the ethylenically unsaturated compound having an epoxy group include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, and 3,2-glycidoxyethyl (meth) acrylate.

The ethylenically unsaturated compound having a hydroxyl group, which is a constituent unit constituting the ethylenically unsaturated compound (a2-3), is a part of the ethylenically unsaturated compound corresponding to the other ethylenically unsaturated compound (a4) described later. It is a compound having a hydroxyl group and a substituent having an ethylenically unsaturated double bond in its structure and not having an aromatic ring.
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.

As the compound (a2-3), a commercially available product can also be used, for example, EBECRYL450 (Mw: 1,600), EBECRYL800 (Mw: 780), EBECRYL810 (Mw: 1,000), EBECRYL812 (Mw: 800), and the like. EBECRYL1830 (Mw: 1,500), EBECRYL846 (Mw: 1,100), EBECRYL851 (Mw: 500), EBECRYL852 (Mw: 500), EBECRYL853 (Mw: 470), EBECRYL884 (Mw: 1,250), E Mw: 1,350) (manufactured by Daisel Ornex);

For example, Aronix M-8030 (Mw: 400), Aronix M-8060 (Mw: 6,000) (manufactured by Toa Synthetic Co., Ltd.); Miramer PS420 (Mw :) 3,000 (manufactured by Toyo Chemicals Co., Ltd.); Aliphatic polyester acrylate Aliphatic polyester acrylate oligomers (product name "CN series" manufactured by Sartmer); aliphatic polyester acrylate oligomers (product name "6000 series" manufactured by Choko Co., Ltd.); aliphatic polyester acrylate oligomers (product name "SP series" manufactured by SOLTECH), etc. However, it is not particularly limited to these.

The ethylenically unsaturated compound (a2-3) can be produced via a conventionally known reaction method of polyester. For example, it can be obtained by the following method.
The polycarboxylic acid and the polyol are subjected to a dehydration reaction or transesterification reaction at 150 to 260 ° C., preferably 180 to 250 ° C., and then heated to 150 to 280 ° C., preferably 160 to 250 ° C. under a reduced pressure of 5 Torr or less. To produce a low molecular weight polyester by removing excess unreacted components.
Then, after cooling to 80 ° C., an ethylenically unsaturated compound having a hydroxyl group, an ethylenically unsaturated compound having an epoxy group, or an ethylenically unsaturated compound having a carboxyl group is added to carry out an esterification reaction, and the excess is not excessive under reduced pressure. The reaction component is removed to prepare a polyester acrylate oligomer.
If the polymerization temperature is less than the above lower limit, the reaction does not proceed sufficiently. On the other hand, if the polymerization temperature exceeds the upper limit, side reactions such as decomposition may occur or the color may be significantly colored, which is not preferable. The reaction time can usually be about 1 to 60 hours. Further, there is no particular problem as long as it is in the range of the following mass average molecular weight (Mw).

From the viewpoint of removability, the mass average molecular weight (Mw) of the ethylenically unsaturated compound (a2) is preferably 200 to 8,000, more preferably 500 to 7,000, and most preferably 500 to 6,000. When Mw is in this range, it is oriented at the interface between the adhesive layer and the adherend in the adhesive layer and changes the surface polarity. 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. Further, since it does not have an aromatic ring, it can be excellent in various performances such as imparting a good texture.

<< Ethylene unsaturated compound (a3) >>
The ethylenically unsaturated compound (a3) is an ethylenically unsaturated compound having a carbonyl group, and is a compound having no carboxyl group and an aromatic ring. However, the ethylenically unsaturated compound (a2) is excluded.
Further, even if it has an alkyl group having 4 to 24 carbon atoms, if it has a carbonyl group, it corresponds to the ethylenically unsaturated compound (a3).
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 an acyl group, carbon-oxygen double bonds contained in a carboxyl group, an acid anhydride group (-C (= O) OC (= O)-), an amide group and an ester group are also available. It shall not be included in the above "carbonyl group".

Examples of the ethylenically unsaturated compound (a3) include 2-oxobutanoylethyl (meth) acrylate, 2-oxobutanoylpropyl (meth) acrylate, and 2-oxobutanoylbutyl (meth) acrylate. 2-oxobutanoylhexyl acrylate, (meth) 2-oxobutanoyloctyl acrylate, 2-oxobutanoyldecyl (meth) acrylate, 2-oxobutanoyldodecyl (meth) acrylate, (meth) Acrylic acid 3-oxobutanoylethyl, (meth) acrylate 3-oxobutanoylpropyl, (meth) acrylate 3-oxobutanoylbutyl, (meth) acrylate 3-oxobutanoylhexyl, (meth) acrylic acid 3-oxobutanoyloctyl, (meth) acrylate 3-oxobutanoyldecyl, (meth) acrylate 3-oxobutanoyldodecyl, (meth) acrylate 4-cyanooxobutanoylethyl, (meth) acrylate 4 -Cyanooxobutanoylpropyl, (meth) acrylate 4-cyanooxobutanoylbutyl, (meth) acrylate 4-cyanooxobutanoylhexyl, (meth) acrylate 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) octyl and other aliphatic (meth) acrylic acid esters having two carbonyl groups;

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 include, but are not limited to, (meth) acrylamides.

As described above, by using the ethylenically unsaturated compound (a3) as a monomer unit constituting the water-dispersible polymer (A), a carbonyl group is introduced into the water-dispersible polymer (A). be able to. Having a carbonyl group in this way is one or more 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 (C) 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 water-based pressure-sensitive adhesive of the present invention containing the water-dispersible polymer (A) and the reactive compound (C) 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 ethylenically unsaturated compounds (a3), 2-oxobutanoylethyl acrylate, 2-oxobutanoylethyl methacrylate, etc., are considered in view of Michael's addition reactivity, price, and industrial availability. (Meta) acrylic acid esters having two carbonyl groups, aliphatic (meth) acrylamides having one carbonyl group such as N- (1,1-dimethyl-3-oxobutyl) acrylamide. Is particularly preferable.

<< Ethylene unsaturated compound (a4) >>
The ethylenically unsaturated compound (a4) is a non-ethylenically unsaturated compound (a1), an ethylenically unsaturated compound (a2), an ethylenically unsaturated compound (a2), and an ethylenically unsaturated compound (a3). Other ethylenically unsaturated compounds having no carboxyl group and aromatic ring, including the ethylene unsaturated compound having a hydroxyl group and the ethylene unsaturated compound having an epoxy group described in the description of the ethylenically unsaturated compound (a2). However, the case of the reactive surfactant (B) described later is excluded.
By using the ethylenically unsaturated compound (a4) as a part of the constituent monomer as needed, the ethylenically unsaturated compound (a1) which is a monomer constituting the water-dispersible polymer (A) is used. ), The ethylenically unsaturated compound (a2), and the ethylenically unsaturated compound (a3) may be facilitated to improve the efficiency of the copolymerization reaction. 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 the ethylenically unsaturated compound (a4) include (meth) acrylic acid alkyl esters such as methyl (meth) acrylate and (meth) ethyl acrylate; vinyl esters such as vinyl acetate and vinyl propionate; ( Acrylamides such as meth) acrylamide and dimethyl (meth) acrylamide; vinyl ethers such as ethyl vinyl ether and propyl vinyl ether; (meth) acrylic acid such as 2-methoxyethyl (meth) acrylate and 2-ethoxyethyl (meth) acrylate. Alkylene esters; (meth) methoxydiethylene glycol acrylate, (meth) methoxypolyoxyethylene acrylate (number of moles added with EO: 3 to 20), (meth) methoxypolyoxypropylene acrylate (number of moles added with PO: 2 to 20) ) And the like (meth) acrylic acid esters; ethylenically unsaturated compounds having a hydroxyl group shown in the above compound (2); ethylenically unsaturated compounds having an epoxy group shown in the above compound (2); In addition, (meth) acrylonitrile, (meth) perfluoromethyl acrylate, 3- (meth) acryloyloxypropylmethyldimethoxysilane, etc. may be mentioned, but from the viewpoint of removability, adhesion to a substrate, and maintenance of curved surface adhesiveness. Therefore, it does not have an aromatic ring.

<< Production method of water-dispersible polymer (A) >>
The water-dispersible polymer (A) includes an ethylenically unsaturated compound (a1), an ethylenically unsaturated compound (a2) and an ethylenically unsaturated compound (a3), and if necessary, an ethylenically unsaturated compound (a4). Can be obtained by copolymerizing. 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, or durability. , The ethylenically unsaturated compound (a1), the ethylenically unsaturated compound (a2), the ethylenically unsaturated compound (a3) and, if necessary, the ethylenically unsaturated compound (a4), taking into consideration the coating suitability and the like. ) Can be selected.

The water-dispersible polymer (A) is synthesized by a method such as bulk polymerization, solution polymerization, emulsion polymerization or suspension polymerization by synthesizing a mixture of various 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 a mixture of various ethylenically unsaturated compounds as described above, but is particularly limited. Instead, it can be appropriately selected from a water-soluble polymerization initiator and an oil-soluble polymerization initiator.

Examples of the water-soluble polymerization initiator include potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, and an ammonium (amine) salt 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, Dichlorbenzoylpaoxide, Dicumylpaoxide, Di-t-butylpaoxide, 1,1-bis (t-butylpaoxy) -3,3,5-trimethyl Cyclohexane, 3,3,5-trimethylcyclohexanone compound, methylcyclohexanone peroxide, di-isobutylpa-oxydica-bonate, di-2-ethylhexylpa-oxydica-bonate, 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-) Hydroxyethyl) -propionamide] and other azo compounds 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 hydropaoxide, benzoylpa oxide and the like.
Examples of the reducing agent include sodium sulfite, sodium acid 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 buffering agent is not particularly limited as long as it has a pH buffering action of the reaction solution of emulsion polymerization. Examples of the buffering agent include sodium hydrogen carbonate, potassium hydrogen carbonate, monosodium phosphate, monopotassium phosphate, disodium phosphate, trisodium phosphate, sodium acetate, ammonium acetate, sodium formate, ammonium formate, and tricitrate. Examples include sodium.
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-based compound such as a mercaptan-based compound, a thioglycol-based 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.

The content of each ethylenically unsaturated compound is 85 to 99.98% by mass of the ethylenically unsaturated compound (a1) in 100% by mass of the mixture of the ethylenically unsaturated compounds constituting the water-dispersible polymer (A). , Ethylene unsaturated compound (a2) 0.01 to 10% by mass, and ethylenically unsaturated compound (a3) 0.01 to 5% by mass, preferably ethylenically unsaturated compound (a1) 92 to 99. It is more preferably in the range of .85% by mass, 0.1 to 5% by mass of the ethylenically unsaturated compound (a2), and 0.05 to 3% by mass of the ethylenically unsaturated compound (a3).

If necessary, when the ethylenically unsaturated compound (a4) is contained, the ethylenically unsaturated compound (a1) is contained in 100% by mass of the mixture of the ethylenically unsaturated compounds constituting the water-dispersible polymer (A). ) 45-99.97% by mass, ethylenically unsaturated compound (a2) 0.01-10% by mass, ethylenically unsaturated compound (a3) 0.01-5% by mass, and ethylenically unsaturated compound (a4). It is preferably 0.01 to 40% by mass, preferably 62 to 99.84% by mass of the ethylenically unsaturated compound (a1), 0.1 to 5% by mass of the ethylenically unsaturated compound (a2), and an ethylenically unsaturated compound. More preferably, it is in the range of 0.05 to 3% by mass of (a3) and 0.01 to 30% by mass of the ethylenically unsaturated compound (a4).

When the content of each ethylenically unsaturated compound is within the above range, the polar sites associated with the ester bonds and carbonyl groups in the adhesive layer are oriented toward the surface of the adherend, and the surface polarity of the adhesive layer is changed. In addition, it is flexible because it does not have an aromatic ring, and while exhibiting appropriate adhesiveness, when peeled off, contamination of the adherend such as cloudiness and adhesive residue is suppressed, and surface groups are also exhibited. Even when neutral paper or glossy paper containing calcium carbonate is used as the material, the adhesiveness and curved surface adhesiveness do not deteriorate even after long-term storage. Therefore, the glass transition temperature of the water-dispersible copolymer (A) (hereinafter, "Tg"). It may be abbreviated as), and various physical properties such as adhesive strength, curved adhesiveness, various resistances, flexibility, compatibility, emulsifying property and removability can be appropriately controlled.

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. It is preferable to select the composition ratio of each monomer which is a constituent component of the water-dispersible polymer so that the temperature is preferably −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 calorimeter (DSC) described later. Details of the method for measuring the glass transition temperature (Tg) are described in Examples.

<Reactive surfactant (B)>
Next, the reactive surfactant (B) will be described.
The water-dispersible polymer (A) can be obtained by emulsion polymerization of a mixture containing the ethylenically unsaturated compound (a). The surfactant used in the emulsifying polymerization is preferably selected from anionic surfactants and / or nonionic surfactants as appropriate, and among them, it is effective in suppressing adherent contamination derived from the surfactants. Reactive surfactants are preferably used.
The reactive surfactant (B) is a surfactant having a reactive group copolymerizable with the ethylenically unsaturated compound (a) constituting the water-dispersible polymer (A) and having no aromatic ring. ..
By containing the reactive surfactant (B), it becomes possible to prevent fogging and adhesive residue derived from the surfactant when the adhesive sheet is peeled off from the adherend, and the re-peelability is further 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 water resistance and moisture heat resistance of the adhesive layer are not impaired, good removability is exhibited, and the storage stability of the water-based pressure-sensitive adhesive is improved. It will be possible to secure it.

When the reactive surfactant (B) is used during the emulsification polymerization in the production of the water-dispersible polymer (A), the reactive surfactant (B) is composed of the water-dispersible surfactant (A). As a unit, the content of each compound is ethylenically unsaturated in 100% by mass of the mixture of the ethylenically unsaturated compound (a) constituting the water-dispersible polymer (A) and the reactive surfactant (B). Compound (a1) 75 to 99.88% by mass, ethylenically unsaturated compound (a2) 0.01 to 10% by mass, ethylenically unsaturated compound (a3) 0.01 to 5% by mass, and reactive surfactant. (B) The content is preferably 0.1 to 10% by mass, preferably 87 to 99.35% by mass of the ethylenically unsaturated compound (a1), 0.1 to 5% by mass of the ethylenically unsaturated compound (a2), and ethylenically. More preferably, it is in the range of 0.05 to 3% by mass of the unsaturated compound (a3) and 0.5 to 5% by mass of the reactive surfactant (B).

If necessary, when the ethylenically unsaturated compound (a4) is contained as a constituent unit, the ethylenically unsaturated compound (a) constituting the water-dispersible polymer (A) and the reactive surfactant ( Ethylene unsaturated compound (a1) 35 to 99.87% by mass, ethylenically unsaturated compound (a2) 0.01 to 10% by mass, ethylenically unsaturated compound (a3) 0 in 100% by mass of the mixture of B). It is preferably 0.01 to 5% by mass, ethylenically unsaturated compound (a4) 00.01 to 40% by mass, and reactive surfactant (B) 0.1 to 10% by mass, preferably an ethylenically unsaturated compound. (A1) 57 to 99.34% by mass, ethylenically unsaturated compound (a2) 0.1 to 5% by mass, ethylenically unsaturated compound (a3) 0.05 to 3% by mass, ethylenically unsaturated compound (a4) ) 0.01 to 30% by mass, and the reactive surfactant (B) is more preferably in the range of 0.5 to 5% by mass.

Examples of the anionic reactive surfactant include polyoxyethylene alkylpropenyl ether sulfate ester ammonium, polyoxyethylene styrenated propenylphenyl ether sulfate ester 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-ethandyl) ammonium, polyoxyethylene-1- (allyloxymethyl) alkyl ether. Polyoxyethylene alkyl alkenyl ether sulfate ester 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 sulfosuccinic acid alkenyl ether, alkyl alkenyl succinic acid 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 substrate which is the support. It is preferable to contain an ethylene alkylalkenyl ether sulfate ester salt.

<Reactive compound (C)>
The reactive compound (C) is a reactive compound having a functional group capable of reacting with a carbonyl group.
The reactive compound (C) can be used as a cross-linking agent for the water-dispersible polymer for cross-linking between the particles of the water-dispersible polymer (A). The compound (C) is a compound that can react with the water-dispersible polymer (A). Further, the case of the reactive surfactant (B) is excluded.
The cross-linking agent for the water-dispersible polymer is essentially non-reactive with respect to the water-dispersion particles in the water-dispersible liquid, but when water is removed from the water-dispersible liquid by drying, the water-dispersible polymer is obtained. 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 cross-linked, 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, and adhesive residue and fogging can be prevented. It is less likely to occur and the removability is improved.

Examples of the functional group capable of reacting with the carbonyl group of the reactive compound (C) include a hydroxyl group, an amino group, an imino group, a hydrazino group, a nitrogen-containing heterocyclic group having active hydrogen, and the like, and the water-dispersible weight. A compound having two or more functional groups in the molecule capable of reacting with the carbonyl group of the coalesced (A) is preferably used. In particular, a hydrazine derivative having a hydrazino group is preferably used because it is excellent in adhesiveness after a crosslinking reaction and adhesion to a substrate described later.

As the hydrazine derivative, any compound having one or more hydrazine groups (-NHNH ₂ ) in the molecule can be suitably used without limitation. For example, carbodihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succi acid dihydrazide, glutalic acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide, ethylene-1,2-dihydra. 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-hydrazidemethyloctane;

Examples thereof include tetracarboxylic acid tetrahydrazides such as pyromellitic acid tetrahydrazide, 1,4,5,8-naphthoic acid tetrahydrazide, ethylenediamine tetraacetate tetrahydrazide, and these may be used alone. 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 in terms of stability and reactivity of the water-dispersible polymer.

The reactive compound (C) is contained in an amount of 0.01 to 10 parts by mass, preferably 0.01 to 5 parts by mass, preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the water-dispersible polymer (A). More preferred. When the content of the reactive compound (C) is in this range, not only the heat resistance and the moist heat resistance are improved by the crosslinking reaction, but also the floating, peeling or foaming of the adhesive layer in a harsh environment is further suppressed. And the removability is further improved.

<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 another compound (F) in addition to the above components as long as the problem can be solved.
The other compound (F) is a compound other than the water-dispersible polymer (A), the reactive surfactant (B), and the 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, non-reactive surfactants, thickeners, preservatives, rust preventives, freeze-melt stabilizers, colorants, fillers, wetting agents, antioxidants, flame retardants, storage stabilizers, UV absorbers, thixotropics. Examples thereof include an imparting agent, a dispersion stabilizer, a fluidity imparting agent, a film-forming auxiliary, a moisturizing agent, a pH adjusting agent, a leveling agent, a defoaming agent, a viscosity adjusting agent, and other additives.

<Manufacturing method of water-based pressure-sensitive adhesive>
As described above, the water-based pressure-sensitive adhesive of the present invention comprises the water-dispersible polymer (A) and the reactive compound (C), as well as the reactive surfactant (B) and other compounds (B), if necessary. It is obtained by coexisting F).
The non-volatile content concentration of the water-based pressure-sensitive adhesive is not particularly limited, but is usually adjusted to about 40 to 70% by mass depending on the usage mode. 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 them 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 sufficient adhesive strength.
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, more preferably. 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 substrate by coating, and it is also easy to improve the adhesive characteristics 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%. It is more preferable to have. When Gel% is in this range, when the adhesive sheet formed of the approximately 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 of applying a water-based pressure-sensitive adhesive to the peeled surface of the above, drying it, and adhering a base material to the surface.

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 intended use.

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 crosslink density. The laminated body laminated in the structure of the base material / adhesive layer / adherend in this way is called a bonded laminated body.

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 of the base materials is the base material (referred to as an adherend) to which the base material is attached). 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 materials used for bonding materials such as gypsum board, ceiling materials, decorative parts, door rims, seat sheets, instrument panels , Dash silencer, center console, pillar trim, rear parcel and other automobile interior materials, and wire binding tape and other wire covering 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.

The base material is a plate 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. Can be mentioned. Further, the base material may be a single body or a laminated body. Further, the base material can be peeled off or antistatic treated on the back surface (opposite surface of the surface to which the adhesive layer is directly bonded). Further, the above-mentioned base material can be coated with a known anchoring agent to improve the adhesion to the adhesive layer.

Of the above base materials, paper is widely used, and printing paper such as cast paper, art paper, and high-quality paper, heat-sensitive paper with a functional layer on these paper, and information paper such as inkjet paper are widely used. Has been done. Conventional paper uses rosin as a sizing agent (to prevent ink bleeding) (also called acid paper), but acid-free paper is paper manufactured in the neutral to weakly alkaline range and is a filler (filler). ) Is mainly used as calcium carbonate, so it is different from acid paper. Acid-free paper is nowadays mainly used for books and materials.
The water-based pressure-sensitive adhesive of the present invention can suppress a decrease in adhesiveness due to deterioration even when such neutral paper or the like is used as a base material, and has high-temperature removability and durability. It is possible to achieve both and suppress contamination by high-speed peeling.

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

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.

<Manufacturing of ethylenically unsaturated compound (a2-3)>
(Synthesis Example 1) Ethylene unsaturated compound having a polycarboxylic acid / polyol / epoxy group Polymerization tank and dropping device of a polymerization reaction device equipped with a polymerization tank, a stirrer, a thermometer, a reflux cooler, a dropping device, and a nitrogen introduction tube. The following compounds, catalysts and organic solvents were charged in the following ratios.

[Polymerization tank]
Adipic acid (polycarboxylic acid) 44.43 parts 2-Butyl-2-ethyl-1,3-propanediol (short-chain polyol) 44.29 parts Tetrabutyl titanate (catalyst) 0.002 parts [Dripping device]
4-Hydroxybutyl acrylate glycidyl ether (ethylenically unsaturated compound having an epoxy group) 11.29 parts

After replacing the air in the polymerization tank with nitrogen gas, the temperature was raised to 120 ° C. under a nitrogen atmosphere with stirring and maintained for 1 hour. Then, the polycondensation reaction was carried out while gradually raising the temperature to 150 to 240 ° C. over about 5 hours and distilling the condensed water. Then, the pressure was gradually reduced, and after 0.5 hours, the pressure was reduced to 5 Torr or less, and the reaction was carried out for 1.5 hours while continuing the pressure reduction to remove unreacted components to obtain a polyester dicarboxylic acid having an acid value of 35 mgKOH / g. rice field.
Next, nitrogen and air were introduced so that the oxygen concentration became about 10%, the temperature of the polymerization tank was lowered to 80 ° C., and the above mixture was dropped at a constant velocity from a dropping device over 1 hour. After completion of the dropping, 0.002 part of zinc oxide (catalyst) was added with further stirring, and a cycloaddition reaction was carried out over 4 hours. Then, the temperature of the polymerization tank was raised to 100 ° C., the pressure was gradually reduced to 5 Torr or less under reduced pressure, and distillation was carried out under reduced pressure for 2 hours to remove unreacted components. Then, the polyester acrylate oligomer is cooled to room temperature, has a pale yellow transparent liquid appearance, has a solution viscosity (Vis) of 5,000 mPa · s (25 ° C.), and has a mass average molecular weight (Mw) of 3,000, as shown in Table 1-2. (A2-3) was obtained. 1 H-NMR measurement was performed, and it was confirmed that the target product was produced.

(Synthesis Example 2) Ethylene unsaturated compound having polycarboxylic acid / polyol / hydroxyl group In a polymerization tank and a dropping device of a polymerization reaction device equipped with a polymerization tank, a stirrer, a thermometer, a reflux cooler, a dropping device, and a nitrogen introduction tube. , The following compounds, catalysts and organic solvents were charged in the following ratios, respectively.

[Polymerization tank]
Adipic acid (polycarboxylic acid) 46.64 parts 2-butyl-2-ethyl-1,3-propanediol (short-chain polyol) 46.49 parts Tetrabutyl titanate (catalyst) 0.002 parts [dropping device]
4-Hydroxybutyl acrylate glycidyl ether (ethylenically unsaturated compound having a hydroxyl group) 6.87 parts

After replacing the air in the polymerization tank with nitrogen gas, a polycondensation reaction was carried out in the same manner as in Synthesis Example 1 to remove unreacted components to obtain a polyester diol having an acid value of 35 mgKOH / g.
Next, nitrogen and air were introduced so that the oxygen concentration became about 10% in the same manner as in Synthesis Example 1, the temperature of the polymerization tank was lowered to 80 ° C., and the above mixture was allowed to flow at a constant velocity over 1 hour from the dropping device. Dropped. After completion of the dropping, 0.002 part of zinc oxide (catalyst) was added while further stirring, and the mixture was kept for 1 hour. Then, the pressure was gradually reduced to 5 Torr or less under reduced pressure, and the esterification reaction was carried out over 8 hours. Then, the temperature of the polymerization tank was raised to 100 ° C. and distillation was carried out under reduced pressure for 2 hours to remove unreacted components. Then, the polyester acrylate oligomer is cooled to room temperature, has a pale yellow transparent liquid appearance, has a solution viscosity (Vis) of 6,000 mPa · s (25 ° C.), and has a mass average molecular weight (Mw) of 3,000, as shown in Table 1-2. (A2-3) was obtained. 1 H-NMR measurement was performed, and it was confirmed that the target product was produced.

(Synthesis Examples 3 and 4)
The compounds of Synthesis Examples 3 and 4, respectively, were subjected to the same reaction as in Synthesis Example 2 except that the types and amounts of the compounds constituting the ethylenically unsaturated compound (a2-3) were changed according to Table 1-1. Was synthesized. The appearance, liquid viscosity (Vis) and mass average molecular weight (Mw) of the obtained compound were determined according to the method described below, and the results are shown in Table 1-2.

(Synthesis Example 5) Ethylene unsaturated compound having a polycarboxylic acid / polyol / carboxyl group Polymerization tank and dropping device of a polymerization reaction device equipped with a polymerization tank, a stirrer, a thermometer, a reflux cooler, a dropping device, and a nitrogen introduction tube. The following compounds, catalysts and organic solvents were charged in the following ratios.

[Polymerization tank]
Adipic acid (polycarboxylic acid) 45.31 parts 2-Butyl-2-ethyl-1,3-propanediol (short-chain polyol) 52.30 parts Tetrabutyl titanate (catalyst) 0.002 parts [dropping device]
Acrylic acid (ethylenically unsaturated compound having a carboxyl group) 2.40 parts

After replacing the air in the polymerization tank with nitrogen gas, a polycondensation reaction was carried out in the same manner as in Synthesis Example 1 to remove unreacted components to obtain a polyester diol having a hydroxyl value of 18 mgKOH / g.
Next, nitrogen and air were introduced so that the oxygen concentration became about 10%, and the reaction was carried out in the same manner as in Synthesis Example 2. The solution viscosity (Vis) was 4,500 mPa · s (25) with a colorless and transparent liquid appearance. The polyester acrylate oligomer (a2-3) shown in Table 1-2 having a mass average molecular weight (Mw) of 2,800 was obtained. 1 H-NMR measurement was performed, and it was confirmed that the target product was produced.

(Synthesis Examples 6, 9, 10)
By reacting in the same manner as in Synthesis Example 5, except that the types and amounts of the compounds constituting the ethylenically unsaturated compound (a2-3) were changed according to Table 1-1, respectively, Synthesis Examples 6, 9, and 10 were carried out. Compounds were synthesized. Of these, the compounds obtained in Synthesis Examples 9 and 10 are compounds (for comparative examples) that are not ethylenically unsaturated compounds (a2-3). The appearance, liquid viscosity (Vis) and mass average molecular weight (Mw) of the obtained compound were determined according to the method described below, and the results are shown in Table 1-2.

(Synthesis Example 7) Ethylene unsaturated compound having a polyester polyol / carboxyl group The following is added to the polymerization tank and the dropping device of the polymerization reaction device equipped with a reaction tank, a stirrer, a thermometer, a reflux cooler, a dropping device, and a nitrogen introduction tube. The compound, catalyst and organic solvent were charged in the following ratios.

[Reaction tank]
F2010 (polyester polyol) 90.07 parts Acrylic acid (ethylenically unsaturated compound having a carboxyl group) 9.93 parts

Nitrogen and air are introduced so that the oxygen concentration in the reaction vessel becomes about 10%, the temperature of the reaction vessel is raised to 80 ° C., and 0.002 part of zinc oxide (catalyst) is added while further stirring. It was held for 1 hour. Then, the pressure was gradually reduced to 5 Torr or less under reduced pressure, and the esterification reaction was carried out over 8 hours. Then, the temperature of the polymerization tank was raised to 100 ° C. and distillation was carried out under reduced pressure for 2 hours to remove unreacted components. Then, it is cooled to room temperature, and has a colorless and transparent liquid appearance, a solution viscosity (Vis) of 8,000 mPa · s (25 ° C.), and a mass average molecular weight (Mw) of 2,500. a2-3) was obtained. ^{1 1} H-NMR measurement was performed and it was confirmed that the target product was produced.

(Synthesis Example 8)
The compounds of Synthesis Example 8 were synthesized by reacting in the same manner as in Synthesis Example 7, except that the types and amounts of the compounds constituting the ethylenically unsaturated compound (a2-3) were changed according to Table 1-1. bottom. The appearance, liquid viscosity (Vis) and mass average molecular weight (Mw) of the obtained compound were determined according to the method described below, and the results are shown in Table 1-2.

《Liquid appearance》
Ethylene unsaturated compounds (a2-3) (for Examples) obtained in Synthesis Examples 1 to 8 and compounds other than the ethylenically unsaturated compounds (a2-3) obtained in Synthesis Examples 9 and 10 (Comparative Examples). The appearance of each was visually observed under the conditions of 25 ° C. It is good if it is not extremely blackish.

<< Liquid Viscosity (Vis) >>
Ethylene unsaturated compounds (a2-3) (for Examples) obtained in Synthesis Examples 1 to 8 and compounds other than the ethylenically unsaturated compounds (a2-3) obtained in Synthesis Examples 9 and 10 (Comparative Examples). The appearance of each was measured at 25 ° C. with a B-type viscosity meter (TV-22 manufactured by Toki Sangyo Co., Ltd.) under the conditions of rotor Nos. 2 to 4, rotation speed of 0.5 to 100 rpm, and rotation for 1 minute. The viscosity of the liquid (mPa · s) was used.

<< Mass average molecular weight (Mw) >>
Ethylene unsaturated compounds (a2-3) (for Examples) obtained in Synthesis Examples 1 to 8 and compounds other than the ethylenically unsaturated compounds (a2-3) obtained in Synthesis Examples 9 and 10 (Comparative Examples). The mass average molecular weight (Mw) of the appearance was measured using GPC (gel permeation chromatography) manufactured by Shimadzu Corporation. The mass average molecular weight (Mw) was determined using the converted value of polystyrene, which is a standard substance.
Device name: SHIMADZU Prominence (manufactured by Shimadzu Corporation)
Detector: Differential refractive index detector Column: SHODEX LF-804 (manufactured by Showa Denko KK) is connected in series. Mobile phase solvent: Tetrahydrofuran (THF)
Flow rate: 0.5 ml / min Column temperature: 40 ° C
Sample concentration: 0.1%
Sample injection amount: 100 μL

The abbreviations of the materials used in Synthesis Examples 1 to 10 are shown below. Unless otherwise specified, the numerical values in the table indicate parts, and the blanks indicate no compounding.

<Abbreviations in Tables 1-1 and 1-2>
-Polycarboxylic acid ADA: Adipic acid-Short chain polyol BEPG: 2-butyl-2-ethyl-1,3-propanediol, MPD: 3-methyl-1,5-pentanediol,
-Polyester polyol F2010: Polyester polyol (Kuraray polyol F-2010 (Mw: 2,000, hydroxyl value :: 84 mgKOH / g) [manufactured by Kuraray Co., Ltd.]), P3010: Polyester polyol (Kuraray polyol P3010 (Mw: 3,000,) Hydroxyl value :: 37 mgKOH / g [manufactured by Kuraray])
-Aromatic OH (polyol having an aromatic ring)
BA2A: 2,2'-{(Propane-2,2-diylbis (4,1-phenylene)} bis (oxy) bis (ethane-1-ol)
-Ethylene unsaturated compound HBGA: hydroxybutyl acrylate glycidyl ether (ethylenically unsaturated compound having an epoxy group), HEA: 2-hydroxyethyl acrylate (ethylenically unsaturated compound having a hydroxyl group), AA: acrylic acid (carboxyl) Ethylene unsaturated compound with a group)
-Aromatic AC (ethylenically unsaturated compound having an aromatic ring)
POPA: 2-acryloyloxyethyl-phthalic acid ・ Catalyst TBT: tetrabutyl titanate, ZNO: zinc oxide

<Manufacturing of 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 in the following ratios.
The FA2D below is an unsaturated fatty acid hydroxyalkyl ester-modified ε-caprolactone (caprolactone 2.0 mol ring-opening addition compound of 2-hydroxyethyl acrylate).

[Stirring tank]
FA2D (Ethylene unsaturated compound (a2-1)) 2.59 parts Butyl acrylate (a1) 94.64 parts 2-acetoacetoxyethyl methacrylate (a3) 0.80 parts 2-hydroxyethyl methacrylate (a4) 0.98 parts KH10 (reactive surfactant) 0.99 parts Ion exchanged water 32.70 parts

The above compounds were mixed while stirring in 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 equipped 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]
Ion-exchanged water 49.07 parts
[Dripping device]
Pre-emulsified product of the above monomer 132.70 parts Potassium persulfate (polymerization initiator) 0.02 parts

After replacing the air in the polymerization tank with nitrogen gas, the temperature was raised to 80 ° C. while stirring under a nitrogen atmosphere, and 0.01 part of potassium persulfate was added.
After 5 minutes, a mixed solution of the pre-emulsified product of the monomer and potassium persulfate was added dropwise from the dropping device over 3 hours.
While maintaining the reaction temperature at 80 ° C. and further stirring, potassium persulfate was added twice every 0.5 hours by 0.005 parts, and then aged for 2 hours to continue the reaction. 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 stain property were evaluated as productivity according to the method described later, and the results are shown in Table 2-2.
Further, the non-volatile content concentration (NV), solution viscosity (Vis), average particle size (Dm), hydrogen ion index (pH) and glass transition temperature (Tg) of the obtained aqueous dispersion were determined according to the method described below. The results are shown in Table 2-2.

(Synthesis Examples 102 to 149)
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 Tables 2-1 and 2 were changed. The numerical values shown in Tables 2-1 and 2 represent "parts" unless otherwise specified, and blanks and "-" notations indicate that they are not used or have not been evaluated.
Of these, Synthesis Examples 102, 111, 112, 134, 135, 140, 141 and 148 are aqueous dispersions that are not aqueous dispersions of the aqueous dispersion polymer (A).
Further, the aqueous dispersions obtained in 101, 103 to 109, 113 to 133, 136 to 139, 142 to 147 and 149 are the aqueous dispersions of the aqueous dispersion polymer (A).

In addition, the mass described in the column of the polymerization initiator in Tables 2-1 and 2 is the total mass added in the polymerization tank, the mass dropped during the dropping, and the post-addition is the mass added twice after the completion of the dropping. Means the sum of. Further, 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 149 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.
[Evaluation criteria]
◯: 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 adhesion 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 149 and the detergency with water were evaluated in three stages. In the case of "○" or "△" evaluation, there is no problem in actual use.
[Evaluation criteria]
◯: 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 to it, and it cannot be removed by washing. Not practical.

<< Non-volatile content concentration (NV) >>
About 1 g of the aqueous dispersion of the water-dispersible polymer obtained in Synthesis Examples 101 to 149 is weighed in a metal container, dried in an oven at 150 ° C. for 20 minutes, and the residue is 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 149 were each subjected to a B-type viscometer (TV-22 manufactured by Toki Sangyo Co., Ltd.) at 25 ° C., rotors No. 2 to 4, and a rotation speed of 0. The viscosity of the liquid (mPa · s) was measured under the conditions of rotation at 5 to 100 rpm for 1 minute.

<< Average particle size (Dm) >>
The average particle size of the aqueous dispersions of the water-dispersible polymers obtained in Synthesis Examples 101 to 149 was measured using "Microtrac" manufactured by Nikkiso Co., Ltd. For the average particle size, a value of 50% of the cumulative percentage was applied.

<< Glass transition temperature (Tg) >>
The glass transition temperature (Tg) of the water-dispersible polymer obtained in Synthesis Examples 101 to 149 was measured by the robot DSC (differential scanning calorimeter, "RDC220" manufactured by Seiko Instruments) and "SSC5200 Disk Station" (manufactured by Seiko Instruments). ) Was connected and measured. Place about 10 mg of the sample in an aluminum pan, weigh it, set it in a differential scanning calorimeter, hold it at a temperature of 100 ° C for 5 minutes using an aluminum pan of the same type without a sample as a reference, and then use liquid nitrogen. 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.

<< Hydrogen ion index (pH) >>
The pH of the aqueous dispersion of the water-dispersible polymer obtained in Synthesis Examples 101 to 149 was measured using F-52S manufactured by HORIBA, electrode: model 6377-10D.

<Abbreviations in Tables 2-1 and 2>
-Ethylene unsaturated compound (a1)
BA: butyl acrylate, 2EHA: 2-ethylhexyl acrylate, LMA: lauryl methacrylate, OVE: n-octylvinyl ether-ethylenically unsaturated compound (a2-1) compound to which a cyclic ester is ring-opened FA2D: unsaturated Fatty acid hydroxyalkyl ester modified ε-caprolactone (2-hydroxyethyl acrylate caprolactone 2.0 mol ring-opening addition compound, Mw: 344) [Dycel's "Plaxel FA2D"], FM5: Unsaturated fatty acid hydroxyalkyl ester modified ε- Caprolactone (5.0 mol ring-opening addition compound of caprolactone of 2-hydroxyethyl methacrylate, Mw: 700) ["Plaxel FM5" manufactured by Daicel Co., Ltd.]
Ethylene unsaturated compound (a2-2) macromonomer AB6: A compound in which a methacryloyl group is added to the end of a polymer of butyl acrylate (Mw: 6,000) [“Macromonomer AB-6” manufactured by Toa Synthetic Co., Ltd.] , AA6: Compound with a methacryloyl group added to the end of a polymer of methyl methacrylate (Mw: 6,000) ["Macromonomer AA-6" manufactured by Toa Synthetic Co., Ltd.]
Ethylene unsaturated compound (a2-3) polyester acrylate oligomer synthesis example: Compounds (a2) (synthesis examples 1 to 10) obtained in each synthesis example shown in Tables 1-1 and 1-2, E846: polyester acrylate. Oligomer (Mw: 1,100) ["EBECRYL 846" manufactured by Daisel Ornex], M8030: Polyester acrylate oligomer (Mw: 400) ["Aronix M-8030" manufactured by Toagosei Co., Ltd.]
-Ethylene unsaturated compound (a3)
AAEM: 2-acetoacetoxyethyl methacrylate, DAAM: diacetoneacrylamide-ethylenically unsaturated compound (a4)
EA: Ethyl acrylate, MMA: Methyl methacrylate, 2HEMA: 2-Hydroxyethyl methacrylate-COOH compound (ethylenically unsaturated compound having a carboxyl group)
AA: Acrylic acid,
-Aromatic ring A (ethylenically unsaturated compound having an aromatic ring)
PHEA: Phenoxyethyl acrylate-Reactive surfactant (B)
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 Methylenebispolyoxyethylene alkylphenylalkenyl ether ammonium sulfate [Japan "Antox MS-60" manufactured by Embroidery Co., Ltd.] Non-volatile content concentration: 90%, ER20: Nonionic reactive surfactant Allyloxymethylalkoxyethyl hydroxypolyoxyethylene ["Adecaria Soap ER-20" manufactured by Adeca Co., Ltd.] Non-volatile Reactivity: 75%
-Non-reactive surfactant WX: Anionic non-reactive surfactant Sodium polyoxyethylene alkyl ether Sulfate ["Latemuru WX" manufactured by Kao Co., Ltd.] Non-volatile content concentration: 26%
-Polymerization initiator APS: Ammonium persulfate
・ 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 149, 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 adjuster, defoaming agent, preservative And plasticizer} were charged in the following ratios (both are non-volatile components).

[Stirring tank]
Water-dispersible polymer of Synthesis Example 101 (A) 100 parts Adipic acid dihydrazide (C) 0.5 parts Adecanol UH-420 (viscosity adjuster) 0.4 parts SN deformer 154 (antifoaming agent) 0.3 parts Dell Top 100N (preservative) 0.05 copies

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 5,000 rpm for 0.5 hours. Next, while stirring, 0.3 part of Acrysol ASE-60 (viscosity adjusting agent), 0.5 part of ammonia water and 9.2 parts of 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 following method, and the results were obtained in Table 3-1. It was shown to.

(Examples 2 to 45, Comparative Examples 1 to 10)
Among the materials listed in Tables 3-1 and 2, the water-dispersible polymer (A), the reactive compound (C), the viscosity modifier, the defoaming agent, the preservative and the plasticizer are listed in Tables 3-1 and 2. The mixture was blended according to the description and stirred and mixed to obtain water-based pressure-sensitive adhesives.
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 respective results are shown in Tables 4-1 and 2.
The numerical values of the water-dispersible polymer (A), the reactive compound (C) and the other compound (F) shown in Tables 3-1 and 2 represent non-volatile components, and blanks indicate that they are not used. ..

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

<< Liquid Viscosity (Vis) >>
The water-based pressure-sensitive adhesives obtained in each Example and Comparative Example were subjected to rotor Nos. 2 to 4 and a rotation speed of 0. The viscosity of the liquid (mPa · s) was measured under the conditions of rotation at 5 to 100 rpm for 1 minute.

<< Hydrogen ion index (pH) >>
The pH of the water-based pressure-sensitive adhesives obtained in each Example and Comparative 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 adhesive obtained in each Example and Comparative Example was placed on a release liner (polyethylene terephthalate film having a thickness of 38 μm and peeled, Therapy MF: manufactured by Toray Film Processing Co., Ltd.) to increase the thickness after drying. The adhesive layer was formed by coating to 20 μm and drying with hot air at 100 ° C. for 2 minutes. Next, a 50 μm-thick polyethylene terephthalate film (PET film) was bonded 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, it is cut into a width of 100 mm and a length of 200 mm, and the surface of the adhesive layer after the peeling liner is peeled off from the end of the adhesive sheet is wrapped in a pre-weighed 200 mesh stainless steel net, which is then put 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 content 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 (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 criteria]
◯: 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.

<< Evaluation of storage stability >>
The water-based pressure-sensitive adhesive obtained in each Example and Comparative Example was 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 the water-based pressure-sensitive adhesive was used. The state of separation between the dispersoid and the liquid layer (dispersion medium) was evaluated in three stages. In the case of "○" or "△" evaluation, there is no problem in actual use.
[Evaluation criteria]
◯: 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 and Comparative Example was collected, diluted with 5 g of water and filtered through a 300-mesh wire mesh, and 50 g of the adhesive was used as a test sample. 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 by the production ratio (%) of the agglomerates. In the case of "○" or "△" evaluation, there is no problem in actual use.
The agglomerate formation ratio was calculated by the following method.
Aggregate formation rate (%) = 100 × (aggregate mass) / (initial mass of test sample)
[Evaluation criteria]
◯: The agglomerate formation ratio is less than 0.1%. Good.
Δ: The agglomerate formation ratio is in the range of 0.1 to 1.0%. Can be used practically.
X: The agglomerate formation ratio exceeds 1.0%. Not practical.

<< 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 at 100 ° C. for 2 minutes with hot air. Next, a commercially available high-quality paper having a thickness of 60 μm was bonded to the coated surface to prepare a high-quality paper / adhesive layer / glassine separator (an adhesive sheet composed of a release liner was prepared, and an adhesive layer after the glassine separator was peeled off. The state of the surface (coated surface) was visually observed and evaluated on a three-point scale. In the case of "○" or "Δ" evaluation, there is no problem in actual use.
[Evaluation criteria]
◯: 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-mentioned << 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 end of the adhesive sheet when pressed at 40 ° C.-60 kg / cm2 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.
[Evaluation criteria]
◯: 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 produced 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 (“Tensilon” manufactured by Orientec) 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 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). Measurement of peel strength after time). This peel strength was evaluated as an adhesive force in three stages. In the case of "○" or "△" evaluation, there is no problem in actual use.
[Evaluation criteria]
◯: 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). Can be used practically.
X: Adhesive strength is less than 3.0 (N / 25 mm) or 10.0 (N / 25 mm) or more. Not practical.

<< Evaluation of high-temperature removability >>
Each adhesive sheet produced by the same method as the above << Evaluation of coatability >> was cut into a width of 25 mm × 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 in an atmosphere of 120 ° C. for 24 hours, then left to stand in the same environment for 1 hour, 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.
[Evaluation criteria]
◯: 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. Can be used practically.
X: The base material broke or the stainless steel plate remained significantly contaminated. Not practical.

<< Evaluation of high-speed removability >>
Each adhesive sheet produced by the same method as the above << Evaluation of coatability >> is cut into a width of 25 mm × 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.
[Evaluation criteria]
◯: 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. Can be used practically.
X: The substrate broke or the veneer board remained significantly contaminated. Not practical.

《Measurement of holding power》
Each adhesive sheet produced 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 exposed. 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 under the condition of 40 ° C. The measurement was performed, and the time until the load fell, or if it did not fall, 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.
[Evaluation criteria]
◯: 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. Can be used practically.
×: Fall in less than 70,000 seconds. Not practical.

<< Evaluation of constant load peelability test >>
Each adhesive sheet produced 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 exposed. 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 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 unattached part, 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.
[Evaluation criteria]
◯: Does not fall and has a deviation of less than 20 mm. Good.
Δ: No drop, deviation 20 mm or more and less than 80 mm. Can be used practically.
×: Fall in less than 10 minutes. Not practical.

<< Evaluation of curved surface adhesiveness >>
Each adhesive sheet produced 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 20 mmφ glass cylinder. It was affixed to and crimped with a 2 kg rubber roller, and left for 24 hours in an atmosphere of 23 ° C.-50% RH. Then, the peeling 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.
[Evaluation 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 mm or more and 0.5 mm or less at the end of the sample is peeled off. Practical 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 prepared by the same method as the above << Evaluation of coatability >> and rub the exposed adhesive layer with a finger to see if 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.
[Evaluation criteria]
◯: Does not fall off from the base material even if rubbed more than 15 round trips. Good and practically no problem.
Δ: It falls off from the base material after 5 to 15 round trips. Can be used practically.
X: The pressure-sensitive adhesive falls off in less than 5 round trips. Not practical.

<< Evaluation of acid-free paper peel strength retention rate >>
The water-based pressure-sensitive adhesive obtained in each Example and Comparative Example was applied onto a glassine separator (peeling liner) so that the thickness of the adhesive layer after drying was 20 μm, and the temperature was 100 ° C. for 3 minutes. An adhesive layer was formed by hot air drying. Next, a 60 μm-thick commercially available acid-free paper (with a basis weight of 80 g / m2 and containing about 15% calcium carbonate) is bonded to the coated surface to form a neutral paper / adhesive layer / glassine separator (peeling liner). An adhesive sheet was prepared.
Each of the produced adhesive sheets was cut into a width of 25 mm and a length of 100 mm, the glassine separator (peeling liner) was peeled off, and the exposed adhesive layer was placed on a stainless steel plate having a thickness of 3 mm and a polished surface at 23 ° C-50% RH. It was attached underneath, and a roll with a mass of 2 kg was reciprocated once to obtain a measurement sample. After leaving this measurement sample in an environment of 23 ° C.-50% RH for 1 day, the adhesive strength was adjusted to the same environment using a tensile tester ("Tensilon" manufactured by Orientec Co., Ltd.) at a peeling speed of 300 mm / min and peeling. The peel strength was measured under the condition of an angle of 180 degrees (peeling strength measurement one day after bonding).
Further, each of the prepared adhesive sheets was left in an environment of 60 ° C.-95% RH for 3 days, and then left in an environment of 23 ° C.-50% RH for 1 hour, and the peel strength was measured by the same method. (Measurement of peel strength after 3 days of moist heat).
This peel strength was evaluated as an adhesive force in three stages. In the case of "○" or "△" evaluation, there is no problem in actual use.
[Evaluation criteria]
◯: Adhesive strength is 5.0 (N / 25 mm) or more and 8.0 (N / 25 mm) or less. 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). Can be used practically.
X: Adhesive strength is less than 3.0 (N / 25 mm) or 10.0 (N / 25 mm) or more. Not practical.

In addition, the retention rate of the peel strength after 3 days of moist heat and humidity with respect to the peel strength 1 day after bonding was calculated using the following formula, and the deterioration of the adhesive layer with neutral paper was judged with time and evaluated in 3 stages. In the case of "○" or "△" evaluation, there is no problem in actual use.
Peeling power retention rate (%) = (Peeling strength after 3 days of moist heat / Peeling strength after 1 day of bonding) × 100
[Evaluation criteria]
◯: Peeling force retention rate of 90% or more. Good.
Δ: The peeling force retention rate is 85% or more and less than 90%. Can be used practically.
X: The peeling force retention rate is less than 85%. Not practical.

The materials used in each example and comparative example are shown below. In Tables 3-1 and 3-2 and Tables 4-1 and 4-2, blanks mean no compounding, and "-" indicates unpainted.
Examples of water-dispersible polymer synthesis: Water-dispersible polymers obtained in each of the synthesis examples shown in Tables 1-1 and 2 (Synthesis Examples 1 to 149).
-Reactive compound (C)
ADH: Adipic acid dihydrazide ・ 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 Ltd.
・ 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 Examples 1, 3, 4 to 10, 13, 15, 17, 19, 20, 22 to 26, 29 to 32, 34 to 42, 44 and 45. Then, storage stability, mechanical stability, coatability, workability, peel strength (immediately after 1 day, after heating 72 hours), re-peelability (high temperature, high speed), holding power, constant load peeling, curved surface adhesion In all of the properties, substrate adhesion and peel strength (after 1 day, after 3 days of moist heat and heat, retention rate), the "△" evaluation (practical level) was 3 or less out of 16 items, and all others were "○". Because of the evaluation (good level), it can be seen that it is excellent.
Further, in Examples 2, 11, 12, 14, 16, 18, 21, 27, 28, 33 and 43, the “Δ” evaluation (practical level) of each evaluation is 4 to 16 out of 16 items. , Since there is no "x" evaluation (defective level), it can be used without any problem in practical use.
On the other hand, in Comparative Examples 1 to 10, storage stability, mechanical stability, coatability, processability, peel strength (immediately after 1 day, after heating 72 hours), re-peelability (high temperature, high speed) It can be seen that any of the holding power, constant load peeling, curved surface adhesion, substrate adhesion and peeling strength (after 1 day, after 3 days of moist heat and heat, retention rate) 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, and substrate adhesion. In addition to the general field of labels and sheets, the field of construction (for example, exterior, interior, equipment, etc.), electrical equipment field (for example, home appliances, kitchen equipment, air conditioning, etc.), transport equipment, etc. It can also be used in various industrial fields other than the optical field such as fields (for example, ships, automobiles, etc.), furniture fields, and miscellaneous goods fields.

Claims (7)

It contains a water-dispersible polymer (A) having a carbonyl group and no carboxyl group, and a reactive compound (C) having a functional group capable of reacting with the carbonyl group.
The water-dispersible polymer (A) is a copolymer of a mixture containing the following ethylenically unsaturated compounds (a1) to (a3).
A water-based pressure-sensitive adhesive containing 0.01 to 10 parts by mass of the reactive compound (C) with respect to 100 parts by mass of the water-dispersible polymer (A) and not containing a compound having an aromatic ring.
(A1) Ethylene unsaturated compound having an alkyl group having 4 to 24 carbon atoms (a2) Ethylene unsaturated compound having an ester bond (a3) Ethylene unsaturated compound having a carbonyl group (however, an ethylenically unsaturated compound) (A2) is excluded) In 100% by mass of the mixture of ethylenically unsaturated compounds constituting the water-dispersible polymer (A),
The ethylenically unsaturated compound (a1) 70 to 99.98% by mass,
0.01 to 20% by mass of the ethylenically unsaturated compound (a2) and
The ethylenically unsaturated compound (a3) 0.01 to 10% by mass,
The water-based pressure-sensitive adhesive according to claim 1, which comprises. The water-based pressure-sensitive adhesive according to claim 1 or 2, wherein the ethylenically unsaturated compound (a2) has a mass average molecular weight of 200 to 8,000. The water-dispersible polymer (A) is obtained by emulsifying and polymerizing a mixture of ethylenically unsaturated compounds in the presence of a reactive surfactant (B) (excluding the reactive compound (C)). The water-based pressure-sensitive adhesive according to any one of claims 1 to 3. The water-based pressure-sensitive adhesive according to claim 4, wherein the reactive surfactant (B) contains an anionic reactive surfactant. Claim 1 is characterized in that the functional group of the reactive compound (C) is at least one selected from the group consisting of an amino group, an imino group, a hydrazino group, and a nitrogen-containing heterocyclic group having active hydrogen. The water-based pressure-sensitive adhesive according to any one of 5 to 5. An adhesive sheet comprising a base material and an adhesive layer formed of the water-based pressure-sensitive adhesive according to any one of claims 1 to 6.