JP2003171560A - Tackifier resin emulsion, manufacturing method therefor, and aqueous pressure-sensitive adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tackifier resin emulsion with excellent water resistance that is formed by emulsifying a tackifier resin without using an emulsifier, a manufacturing method therefor, and an aqueous pressure-sensitive adhesive composition. <P>SOLUTION: This tackifier resin emulsion is formed by dispersing a tackifier resin (A1) into water by means of a polymer (A2) with a glass transition temperature (Tg) ≥10°C and a weight average molecular weight of 300-50,000, and having an organic acid group in a molecule. The polymer (A2) may be an acrylic polymer having a (meth)acrylate as a monomeric main component. The organic acid group may be a carboxylic acid group. The aqueous pressure- sensitive adhesive composition comprises the tackifier resin emulsion (A), and a pressure-sensitive adhesive (B) having an acrylic polymer (B1) as a base polymer. The tackifier resin emulsion (A) in an amount of 1-50 pts.wt. may be blended with 100 pts.wt. of the pressure-sensitive adhesive (B). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a tackifying resin emulsion having excellent water resistance, a method for producing the same, and an aqueous pressure-sensitive adhesive composition.

[0002]

2. Description of the Related Art Conventionally, pressure-sensitive adhesive tapes are mainly composed of
Solvent-based pressure sensitive adhesives based on solvent-based acrylic polymers have been used. However, since such solvent-based pressure-sensitive adhesives are synthesized in an organic solvent, volatilization of the solvent during coating is an environmental problem, and water-dispersed pressure-sensitive adhesives (water-based pressure-sensitive adhesives) are used. It is being converted to a drug.
However, the water-based pressure-sensitive adhesive containing an acrylic polymer as a main component has high adhesiveness to polar adherends such as stainless steel and polyethylene terephthalate (polar adherends), but non-polar adhesives such as polyethylene and polypropylene. Adhesiveness to adherends (non-polar adherends) is low and terminal peeling prevention properties after adhesion to these non-polar adherends (property of peeling off end portions of adherend adherents; repulsion resistance) ) Etc. are inferior. In order to improve such a defect, a tackifier (for example, a tackifying resin such as a rosin-based resin, a terpene-based resin, a petroleum resin, etc.) is blended in the pressure-sensitive adhesive composition.

However, since the tackifying resin is extremely difficult to disperse in water, a large amount of emulsifier is required to disperse it uniformly in water. Therefore, a water-based pressure-sensitive adhesive composition containing a conventional acrylic emulsion as a main component is affected by a large amount of emulsifier in a tackifying resin emulsion with a large amount of emulsifier, so that the pressure-sensitive adhesive is applied in a high humidity place or a place where water drops are applied. Since the agent itself has a problem that it tends to absorb water, whiten or fog easily, it is not suitable for applications requiring water resistance. That is, since the tackifying resin emulsion itself has low water resistance, the water-based pressure-sensitive adhesive composition itself also has low water resistance.

Under such circumstances, as a method for reducing the amount of emulsifier required when dispersing the tackifying resin in water, in JP-A-10-195407, the tackifying resin and the acrylic monomer are incorporated into the seed polymer for polymerization. The method is shown. However, with this method,
Since the tackifying resin that can be used during the acrylic monomer polymerization is limited to those that do not hinder the polymerization of the acrylic monomer as a result, it is possible to increase the adhesiveness to the non-polar adherend. You cannot select the agent.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a tackifying resin emulsion having excellent water resistance, a method for producing the same, and an aqueous pressure-sensitive adhesive composition. Another object of the present invention is to provide a tackifying resin emulsion in which a tackifying resin is emulsified without using an emulsifier, a method for producing the same, and a water-based pressure-sensitive adhesive composition.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, the tackifier resin has a glass transition temperature (Tg) of 10 ° C. or higher and a weight molecular weight of 30.
It was found that a tackifying resin emulsion having an excellent water resistance can be obtained by emulsifying with a polymer having an organic acid group in the molecule of 0 to 50,000 and dispersing it in water.
The present invention has been completed.

That is, the present invention provides a tackifying resin (A1)
, Which has a glass transition temperature (Tg) of 10 ° C. or higher and a weight average molecular weight of 300 to 50,000 and is dispersed in water by a polymer (A2) containing an organic acid group in the molecule. An applied resin emulsion is provided.

As the polymer (A2), an acrylic polymer containing a (meth) acrylic acid ester as a monomer main component can be used. Further, the organic acid group of the polymer (A2) is preferably a carboxylic acid group.

The present invention also provides a tackifying resin (A1),
A tackifier characterized by having a glass transition temperature (Tg) of 10 ° C. or higher and a weight average molecular weight of 300 to 50,000 and water-dispersing using a polymer (A2) containing an organic acid group in the molecule. A method for producing a resin emulsion is provided.

Furthermore, the present invention is characterized by containing the tackifying resin emulsion (A) and a pressure-sensitive adhesive (B) containing an acrylic polymer (B1) as a base polymer. An aqueous pressure sensitive adhesive composition is provided.
In the water-based pressure-sensitive adhesive composition, the pressure-sensitive adhesive (B) 1
Tackifying resin emulsion (A) for 100 parts by weight
1 to 50 parts by weight is preferably blended.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION [Tackifying Resin (A1)] As the tackifying resin (A1), a tackifying resin known or commonly used as a tackifying resin for pressure-sensitive adhesives can be used. Examples of the tackifying resin (A1) include rosins (A1-a), rosin derivatives (A1-b), petroleum-based resins (A1-
c), terpene resin (A1-d), phenolic resin (A1-
e) and ketone resins (A1-f). The tackifier resin (A1) can be used alone or in combination of two or more kinds.

Examples of rosins (A1-a) include rosins such as gum rosin, wood rosin and tall oil rosin, as well as stabilized rosins and polymerized rosins (for example, stabilizers obtained by disproportionating or hydrogenating the rosins. Rosin, polymerized rosin, etc.), modified rosin (eg, unsaturated acid-modified rosin modified with an unsaturated acid such as maleic acid, fumaric acid, (meth) acrylic acid).

As the rosin derivative (A1-b), various known rosin derivatives derived from the rosins (A1-a) can be used. Specifically, the rosin derivative includes, for example, an esterified product of the rosin (A1-a), a phenol-modified product of the rosin (A1-a), and an esterified product thereof. For example, rosins (A1-
As the esterified product of a), for example, those obtained by subjecting the above-exemplified rosins and a polyhydric alcohol to an esterification reaction can be used. Examples of the polyhydric alcohol include dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol and neopentyl glycol; trihydric alcohols such as glycerin, trimethylolethane and trimethylolpropane; tetrahydric alcohols such as pentaerythritol and diglycerin. Alcohol; hexavalent alcohol such as dipentaerythritol and the like can be mentioned.
The polyhydric alcohols can be used alone or in combination of two or more.

The rosin (A1-a) phenol-modified product and its esterified product include, for example, phenols added to the above-mentioned rosins, and phenols added to the above-mentioned rosins. Esterified products, so-called rosin-modified phenolic resins obtained by reacting a resol-type phenolic resin with the above-mentioned rosins, and esterified products thereof are included.

Examples of the petroleum resin (A1-c) include so-called C5 petroleum resin, so-called C9 petroleum resin, so-called C5-C9 copolymer petroleum resin, pure monomer resin, dicyclopentadiene petroleum resin, Examples thereof include hydrides.

Examples of the terpene resin (A1-d) include α-pinene resin and β-pinene resin, terpenes (eg α-pinene and β-pinene) and aromatic monomers (eg styrene). Aromatically modified terpene-based resins by copolymerization of styrene-based monomers, etc.), terpenes (for example, α-pinene, β-pinene, etc.), and terpene-phenolic resins by copolymerization of phenol.

Examples of the phenolic resin (A1-e) include phenols (eg, phenol, m-cresol, 3,
5-xylenol, p-alkylphenol, resorcin, etc.) and formaldehyde can be used. Specifically, examples of the phenolic resin (A1-e) include resole obtained by addition reaction of phenols and formaldehyde with an alkali catalyst, and novolak obtained by condensation reaction with an acid catalyst. The phenolic resin (A1-e) also includes a rosin phenol resin obtained by adding phenol to an rosin with an acid catalyst and performing thermal polymerization.

The ketone resin (A1-f) includes, for example, ketones (for example, aliphatic ketones such as methyl ethyl ketone, methyl isobutyl ketone and acetophenone, alicyclic ketones such as cyclohexanone and methylcyclohexanone) and formaldehyde. Ketone-based resins obtained by condensation of

The tackifying resin (A1) is not particularly limited and, for example, those having a high softening point of 200 ° C. or less to liquid ones can be appropriately selected and used according to various uses. it can.

[Polymer (A2)] In the present invention, when the tackifying resin (A1) is dispersed in water, the polymer (A2) is used instead of the emulsifier. The glass transition temperature (Tg) of the polymer (A2) is 10 ° C or higher (for example, 10 to 15).
0 ° C.), preferably 15 ° C. or higher (for example, 15 to 120)
C) is important. By setting the Tg of the polymer (A2) to 10 ° C. or higher, the polymer (A2) itself can exhibit the same function as the tackifying resin (A1),
Even if a large amount of polymer (A2) is mixed, tackiness is improved, such as improving adhesion to non-polar adherends (eg polyethylene, polypropylene, etc.) and improving terminal peeling prevention after adhesion to non-polar adherends. The function (or action) or effect of the resin can be effectively exhibited.

Further, it is important that the polymer (A2) contains an organic acid group in the molecule. Examples of such organic acid, for example, a carboxylic acid group (-COOH), sulfonic acid (-SO ₃ H), a phosphoric acid group (-PO ₃ H) and the like. As the organic acid group of the polymer (A2), a carboxylic acid group (carboxyl group) is particularly suitable. In addition,
The organic acid group in the polymer (A2) may be one type or a combination of two or more types.

Further, the weight average molecular weight of the polymer (A2) is 300 to 50,000 (preferably 1,000 to 2).
0000, more preferably 3000 to 15000) is important. Thus, the polymer (A2)
Is a (relatively) low molecular weight polymer. When the molecular weight of the polymer (A2) is too low (for example, when the weight average molecular weight is less than 300), the dispersibility of the tackifying resin (A1) decreases, and when mixed with a pressure sensitive adhesive,
The cohesive force of the pressure-sensitive adhesive decreases, and the pressure-sensitive adhesive cannot exhibit its holding property. On the other hand, if the molecular weight is too high (for example,
If the weight average molecular weight exceeds 50,000), the dispersibility of the tackifying resin (A1) will decrease, and when mixed with a pressure sensitive adhesive, it will adhere to non-polar adherends (eg polyethylene, polypropylene, etc.). The action or effect of increasing the adhesive strength of the imparted resin is reduced, and the terminal peeling prevention property after adhesion to the non-polar adherend is reduced.

In the present invention, as the polymer (A2),
An acrylic polymer having a (meth) acrylic ester (A2-a) as a monomer main component and an organic acid group can be preferably used. As a method for introducing an organic acid group into an acrylic polymer, for example, (1) a (meth) acrylic acid ester (A2-a) as a main component of a monomer is used as a copolymerizable monomer having an organic acid ( Organic acid group-containing monomer) (A2-b)
And a method of copolymerizing with other copolymerizable monomer (A2-c) if necessary, (2) (meth) acrylic acid ester (A2
-a) as the main monomer component and, if necessary, an organic acid is added by a well-known chemical reaction to an acrylic polymer containing other copolymerizable monomer (A2-c) as the copolymerization component. Method etc. are mentioned.

The (meth) acrylic acid ester (A2-a) includes, for example, an alkyl ester of (meth) acrylic acid and an alicyclic hydrocarbon ester of (meth) acrylic acid. In the alkyl ester of (meth) acrylic acid,
As the alkyl group moiety, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, hexyl group,
Heptyl group, octyl group, isooctyl group, 2-ethylhexyl group, nonyl group, isononyl group, decyl group, isodecyl group, undecyl group, dodecyl group (lauryl group),
Examples thereof include tridecyl group, tetradecyl group (myristyl group), pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group (stearyl group) and the like. Also,
In the alicyclic hydrocarbon ester of (meth) acrylic acid, examples of the alicyclic hydrocarbon moiety include a cycloalkyl group such as a cyclopentyl group and a cyclohexyl group; a bridged cyclic hydrocarbon group such as a bornyl group and an isobornyl group. Can be exemplified.

Specifically, the (meth) acrylic acid ester (A2-a) is, for example, methyl (meth) acrylate, ethyl (meth) acrylate, or (meth) acrylic acid n.
-Propyl, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate ,
Neopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate,
2-Ethylhexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, myristyl (meth) acrylate, pentadecyl (meth) acrylate, stearyl (meth) acrylate And other (meth) acrylic acid alkyl esters, and (meth) acrylic acid cyclohexyl, (meth) acrylic acid bornyl, (meth) acrylic acid isobornyl, and other (meth) acrylic acid alicyclic hydrocarbon esters. The (meth) acrylic acid ester (A2-a) can be used alone or in combination of two or more kinds.

As the (meth) acrylic acid ester (A2-a), cyclohexyl acrylate, cyclohexyl methacrylate, bornyl methacrylate, isobornyl methacrylate and methyl methacrylate can be preferably used.

Further, (meth) acrylic acid ester (A2-
Examples of the copolymerizable monomer (A2-c) copolymerizable with a) include
For example, aromatic vinyl compounds such as styrene and substituted styrene; cyano group-containing monomers such as acrylonitrile; olefins such as ethylene and butadiene; vinyl esters such as vinyl acetate; vinyl chloride; acrylamide,
Methacrylamide, N-vinylpyrrolidone, N, N-
Amide group-containing monomers such as dimethyl (meth) acrylamide; hydroxyl group-containing monomers such as hydroxyalkyl (meth) acrylate; amino group-containing monomers such as (meth) acryloylmorpholine; cyclohexylmaleimide, isopropylmaleimide, etc. Imido group-containing monomer; examples thereof include epoxy group-containing monomers such as glycidyl (meth) acrylate. The copolymerizable monomer (A2-c) can be used alone or in combination of two or more kinds.

Examples of the organic acid group-containing monomer (A2-b) used when introducing an organic acid include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, etc. A carboxyl group-containing monomer; and a sulfonic acid group-containing monomer such as sodium vinyl sulfonate. Organic acid group-containing monomer (A2-b)
As the above, a carboxyl group-containing monomer is preferable, and acrylic acid and methacrylic acid are particularly preferable, and acrylic acid is particularly preferable. The organic acid group-containing monomer (A2-b) can be used alone or in combination of two or more kinds.

The acrylic polymer in the polymer (A2) contains (meth) acrylic acid ester (A2-a) as a monomer main component, and (meth) acrylic acid ester (A2-a)
As a ratio to all monomers, for example, 50% by weight
Or more (preferably 80% by weight or more, more preferably 9% by weight)
0% by weight or more) is desirable.

In the present invention, as the polymer (A2), at least one (meth) acrylic acid ester selected from cyclohexyl acrylate, cyclohexyl methacrylate, bornyl methacrylate, isobornyl methacrylate and methyl methacrylate is used as a monomer. As the main component,
A carboxyl group-containing acrylic polymer obtained by copolymerization using acrylic acid and / or methacrylic acid as an organic acid-containing monomer can be preferably used.

[Tackifying Resin Emulsion (A)] The tackifying resin emulsion (A) is the same as the tackifying resin (A).
Prepared by dispersing 1) in water using a polymer (A2) having a glass transition temperature (Tg) of 10 ° C or higher and a weight average molecular weight of 300 to 50,000 and containing an organic acid group in the molecule. To be done. The method for dispersing the tackifying resin (A1) in water is not particularly limited, but the particle size of the emulsified particles made of the tackifying resin (A1) becomes smaller when the high pressure emulsification operation is performed, so that the tackifying resin emulsion (A Is desirable because it can improve the properties of the pressure sensitive adhesive. As an example of the method, for example, the polymer (A2) (acrylic polymer or the like) and the tackifying resin (A2) are mixed in advance with a small amount of an organic solvent, and then water or alkaline water is added. And stir with a stirrer to pre-emulsify. After that, a method in which the particle size of the emulsified particles is made fine by using a high pressure emulsifier and both the solvent and water are removed under reduced pressure can be mentioned.

In the tackifying resin emulsion (A), a large amount of emulsifier is not used, the water resistance of the tackifying resin emulsion (A) itself is improved, and the pressure sensitive adhesive (B) (particularly acrylic resin) is used. Even when used for a pressure-sensitive adhesive, it is possible to suppress or prevent a decrease in water resistance of the pressure-sensitive adhesive (B).

In the tackifying resin emulsion (A), the ratio of the tackifying resin (A1) to the polymer (A2) is not particularly limited, and for example, the tackifying resin (A1) 1
The polymer (A2) is used in an amount of 5 to 100 parts by weight (preferably 10 to 50 parts by weight, more preferably 2 to 100 parts by weight).
0 to 40 parts by weight). Polymer (A2)
If the proportion is too small, the stability of the dispersion liquid will be reduced, while if it is too large, the adhesive properties, such as the adhesive strength, may be deteriorated.

[Pressure-sensitive adhesive (B)] In the present invention, an acrylic polymer (B1) can be used as the base polymer of the pressure-sensitive adhesive (B). The acrylic polymer (B1) contains a (meth) acrylic acid ester (B1-a) as a main component of a monomer, and optionally a copolymerizable monomer (B1-b) as a copolymerization component. Contained as. The acrylic polymer (B1) can be used alone or in combination of two or more kinds.

The (meth) acrylic acid ester (B1-a) includes, for example, an alkyl ester of (meth) acrylic acid and an alicyclic hydrocarbon ester of (meth) acrylic acid. In the alkyl ester of (meth) acrylic acid,
As the alkyl group moiety, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, hexyl group,
Heptyl group, octyl group, isooctyl group, 2-ethylhexyl group, nonyl group, isononyl group, decyl group, isodecyl group, undecyl group, dodecyl group (lauryl group),
Examples thereof include tridecyl group, tetradecyl group (myristyl group), pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group (stearyl group) and the like. Also,
In the alicyclic hydrocarbon ester of (meth) acrylic acid, examples of the alicyclic hydrocarbon moiety include a cycloalkyl group such as a cyclopentyl group and a cyclohexyl group; a bridged cyclic hydrocarbon group such as a bornyl group and an isobornyl group. Can be exemplified.

Specifically, as the (meth) acrylic acid ester (B1-a), for example, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid n
-Propyl, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate ,
Neopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate,
2-Ethylhexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, myristyl (meth) acrylate, pentadecyl (meth) acrylate, stearyl (meth) acrylate And other (meth) acrylic acid alkyl esters, and (meth) acrylic acid cyclohexyl, (meth) acrylic acid bornyl, (meth) acrylic acid isobornyl, and other (meth) acrylic acid alicyclic hydrocarbon esters. The (meth) acrylic acid ester (B1-a) can be used alone or in combination of two or more kinds.

The copolymerizable monomer (B1-b) is, for example, a carboxyl group-containing monomer such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid or isocrotonic acid, or an anhydride thereof. Aromatic vinyl compounds such as styrene and substituted styrene; cyano group-containing monomers such as acrylonitrile; olefins such as ethylene and butadiene; vinyl esters such as vinyl acetate; vinyl chloride; sulfonic acids such as sodium vinyl sulfonate Group-containing monomer; acrylamide, methacrylamide,
Amide group-containing monomers such as N-vinylpyrrolidone and N, N-dimethyl (meth) acrylamide; Hydroxyl group-containing monomers such as hydroxyalkyl (meth) acrylate; Amino group-containing monomers such as (meth) acryloylmorpholine Examples thereof include imide group-containing monomers such as cyclohexylmaleimide and isopropylmaleimide; epoxy group-containing monomers such as glycidyl (meth) acrylate.
The copolymerizable monomer (B1-b) can be used alone or in combination of two or more kinds.

As the copolymerizable monomer (B1-b), if necessary, a silane-based monomer (for example, a silane compound having a (meth) acryloyl group such as a (meth) acryloyloxyalkylsilane derivative) is used. , Vinyltrialkoxysilane, vinylalkyltrialkoxysilane, etc.) may be used. By using the silane-based monomer as a copolymerizable component, it is possible to improve the repulsion resistance when it is applied to an adherend as an adhesive product.

If necessary, a polyfunctional monomer can be used as the copolymerizable monomer (B1-b).
The polyfunctional monomer is not particularly limited as long as it is a polymerizable compound having a plurality of reactive functional groups, for example,
Diethylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri ( Examples thereof include (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and divinylbenzene.

Further, if necessary, a crosslinking agent can be used instead of the polyfunctional monomer (or together with the polyfunctional monomer). As the cross-linking agent, it is possible to use a commonly used cross-linking agent, for example, isocyanate-based cross-linking agent, epoxy-based cross-linking agent, oxazoline-based cross-linking agent,
Examples thereof include aziridine crosslinking agents, metal chelate crosslinking agents, melamine resin crosslinking agents, and peroxide crosslinking agents.

The acrylic polymer (B1) contains (meth) acrylic acid ester (B1-a) as a monomer main component,
The ratio of the (meth) acrylic acid ester (B1-a) to all the monomers is preferably 50% by weight or more (preferably 80% by weight or more, more preferably 90% by weight or more).

Among the above-exemplified examples of the (meth) acrylic acid ester (B1-a), peeling of the terminal portion when attached to a curved surface can be suppressed (excellent in repulsion resistance).
(Meth) acrylic acid C _4-9 alkyl ester (in particular, butyl acrylate and 2-ethylhexyl acrylate) can be preferably used. The pressure-sensitive adhesive product using such an acrylic polymer (B1) containing (meth) acrylic acid C _4-9 alkyl ester as a monomer main component can exhibit good pressure-sensitive adhesiveness.

As the acrylic polymer (B1), if the (meth) acrylic acid ester (B1-a) is the main component of the monomer, the composition of the monomer and the amount or blending ratio thereof are appropriately selected. However, in order to exhibit good pressure-sensitive adhesiveness, the glass transition point (T
It is desirable to determine the composition and the mixing ratio thereof so that g) is usually -20 ° C or lower.

The weight average molecular weight of the acrylic polymer (B1) is 200,000 or more (for example, 200,000 to 700,000), preferably 250,000 to 500,000, more preferably 300,000 to 4
It may be about 50,000. Thus, the acrylic polymer (B1) may be a (relatively) high molecular weight polymer.

In the pressure-sensitive adhesive (B), the acrylic polymer (B1) as a base polymer constituting the pressure-sensitive adhesive may be contained in the form of emulsion.
When the acrylic polymer (B1) is contained in the form of an emulsion, it may be emulsified by using an emulsifier when polymerizing the acrylic polymer (B1), and the acrylic polymer (B1) May be emulsified with an emulsifier. That is, the emulsion containing the acrylic polymer (B1) contains the (meth) acrylic acid ester (B1-a) and, if necessary, the copolymerizable monomer (B1).
-b) and may be an acrylic polymer emulsion obtained by emulsion polymerization, and prepared by obtaining an acrylic polymer (B1) by a polymerization method other than emulsion polymerization and then dispersing it in water with an emulsifier. It may be a prepared acrylic polymer emulsion.

In the present invention, when a polymer such as the polymer (A2) or the acrylic polymer (B1) is prepared, a general polymerization method such as batch polymerization, continuous drop polymerization and divided drop polymerization can be adopted. The polymerization temperature can be selected from the range of 5 to 100 ° C., for example, depending on the kind of the polymerization initiator. Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis [2- (5-methyl- 2-Imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (2
-Methylpropionamidine) disulfate, 2,2'-azobis (N, N'-dimethyleneisobutylamidine) and other azo initiators; potassium persulfate, ammonium persulfate and other persulfates; benzoyl peroxide, t -Peroxide initiators such as butyl hydroperoxide and hydrogen peroxide; combinations of peroxides and reducing agents such as combinations of persulfates and sodium bisulfite, combinations of peroxides and sodium ascorbate Examples of the redox initiator include, but are not limited to, these. The amount of the polymerization initiator used can be appropriately selected depending on the type and the type of acrylic monomer,
Generally, it is, for example, about 0.005 to 1 part by weight (preferably 0.02 to 0.5 part by weight) with respect to 100 parts by weight of the monomer mixture.

A chain transfer agent may be used for the polymerization. By using the chain transfer agent, the molecular weight of the polymer (A2) or the polymer such as the acrylic polymer (B1) can be adjusted. As the chain transfer agent, a conventional chain transfer agent, for example, lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, 2,3-dimethylcapto-1-propanol, etc. Can be illustrated. These may be used alone or in combination of two or more. The amount of the chain transfer agent used is usually about 0.001 to 0.5 part by weight based on 100 parts by weight of the monomer mixture.

In the polymerization, an emulsifier can be used to secure the polymerization stability. Examples of such emulsifiers include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium polyoxyethylene alkyl ether sulfate, ammonium polyoxyethylene alkylphenyl ether sulfate, and sodium polyoxyethylene alkylsulfosuccinate. Nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene polyoxypropylene block polymer, and the like can be used. Further, a radical-polymerizable emulsifier in which a radical-reactive group such as a propenyl group is introduced can also be used. These emulsifiers may be used alone or in combination of two or more. From the viewpoint of polymerization stability and mechanical stability, the amount of the emulsifier used is preferably 0.5 parts by weight or more, and more preferably 1.0 parts by weight or more, based on 100 parts by weight of the monomer mixture. On the other hand, from the viewpoint of improving water resistance, it is preferably 5 parts by weight or less, and more preferably 3 parts by weight or less.

[Water-based pressure-sensitive adhesive composition] The water-based pressure-sensitive adhesive composition of the present invention contains the tackifying resin emulsion (A) and the pressure-sensitive adhesive (B).
The water-based pressure-sensitive adhesive composition can be prepared by mixing the tackifying resin emulsion (A) and the pressure-sensitive adhesive (B). Tackifying resin emulsion (A)
The ratio of the pressure sensitive adhesive (B) to the pressure sensitive adhesive (B) is 1 to 50 parts by weight (preferably 10 to 40 parts by weight) of the tackifying resin emulsion (A) based on 100 parts by weight of the pressure sensitive adhesive (B). It may be a degree. When the tackifying resin emulsion (A) is less than 1 part by weight with respect to 100 parts by weight of the pressure sensitive adhesive (B), almost no modification by the addition of the tackifying resin (A1) is observed, On the other hand, if it exceeds 50 parts by weight, the adhesiveness at low temperature and the cohesive force tend to decrease.

In the water-based pressure-sensitive adhesive composition, if necessary, in addition to a base and an acid for adjusting the pH, additives usually used for pressure-sensitive adhesives, for example, a defoaming agent, a thickener, filler,
Antioxidants, waterproofing agents, film-forming aids, colorants (such as pigments), and antioxidants may be added. In addition,
The viscosity can be adjusted with a base or an acid for adjusting the pH. In this case, the base is, for example, a basic inorganic compound such as ammonia or sodium hydroxide, or a basic organic compound such as an amine compound. Etc. can be used.

The water-based pressure-sensitive adhesive composition of the present invention is excellent in water resistance because a large amount of emulsifier is not used although the tackifying resin is used. Therefore, it can be used under high humidity or in a place where water drops are applied. Moreover, the effect of improving the adhesiveness to the non-polar adherend by the tackifying resin is effectively exhibited, and the terminal peeling prevention property after the adhesion to the non-polar adherend by the tackifying resin is also effectively exhibited. It Furthermore, since a water-based acrylic pressure-sensitive adhesive is used, it is desirable in terms of environmental hygiene.

The water-based pressure-sensitive adhesive composition of the present invention can be used as an adhesive product (eg, adhesive tape, adhesive sheet, adhesive film, adhesive label, etc.). The pressure-sensitive adhesive product includes, for example, a pressure-sensitive adhesive layer formed of the above water-based pressure-sensitive adhesive composition. The pressure-sensitive adhesive layer may be formed on the substrate or may be formed on the release film. Examples of the base material include plastic films such as polypropylene film, polyolefin film, ethylene-propylene copolymer film, polyester film, polyimide film, polyvinyl chloride film and polyvinyl acetate film; paper such as kraft paper; metal foil and the like. Can be used. The plastic film may be either a non-stretched film or a stretched (uniaxially stretched or biaxially stretched) film. In addition, one or both surfaces of the base material may be subjected to appropriate surface treatment such as physical treatment such as corona treatment or plasma treatment, chemical treatment such as undercoating agent, etc. for the purpose of improving the adhesive strength of the pressure-sensitive adhesive layer. . The thickness of the substrate is 10 to 300 μm, preferably 20 to 150
It is about μm.

The water-based pressure-sensitive adhesive composition is prepared by using a conventional coater such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater or a spray coater. It can be applied on a release film. In the pressure-sensitive adhesive composition, the thickness of the pressure-sensitive adhesive layer after drying is, for example, 5 to 200 μm, preferably 1
It is applied so as to have a thickness of about 0 to 100 μm.

It is desirable to laminate a release film on the pressure-sensitive adhesive layer to protect the pressure-sensitive adhesive. When the release film is not used, the back surface of the sheet may be back-treated with a release treatment agent such as a silicone release agent or a long-chain alkyl release agent. The adhesive product may be an adhesive tape wound in a roll.

[0055]

The water-based pressure-sensitive adhesive composition of the present invention is excellent in water resistance because a large amount of an emulsifier is not used when emulsifying the tackifying resin, although it is water-based. .

[0056]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited by these examples. In addition, a part means a weight part. (Preparation example 1 of water-based acrylic pressure-sensitive adhesive) 715 parts of ion-exchanged water was put into a reaction vessel equipped with a thermometer, a stirrer, a nitrogen introducing tube and a reflux cooling tube, and nitrogen substitution was carried out at a temperature of 60 ° C. for 1 hour while stirring. Let 2,2'-azobis (2
-Amidinopropane) dihydrochloride (polymerization initiator) (1.5 parts) was added and the temperature was raised to 60 ° C. After that, 1266 parts of butyl acrylate, 141 parts of 2-ethylhexyl acrylate, 56 parts of acrylic acid, lauryl mercaptan (chain transfer) Agent) 0.73 parts, 3-methacryloxypropyltrimethoxysilane 0.88 parts, sodium polyoxyethylene lauryl sulfate (emulsifier) 21 parts and water 474
What was emulsified in 1 part was added dropwise over 4 hours to carry out emulsion polymerization treatment. After cooling, 100 parts of 10 wt% ammonia water was added for neutralization to obtain an acrylic water-based pressure-sensitive adhesive. The weight average molecular weight of the acrylic polymer as the base polymer in the acrylic water-based pressure-sensitive adhesive (M
w) is 350,000, and the glass transition temperature (T
g) is -58 ° C.

(Preparation Example 1 of Organic Acid-Containing Polymer) A reaction vessel equipped with a thermometer, a stirrer, a nitrogen introducing tube and a reflux cooling tube was charged with 190 parts of cyclohexyl methacrylate, 10 parts of acrylic acid, and 0.1 part of azobisisobutyronitrile. 6 copies, 2
-Mercaptoethanol (4 parts) and toluene (100 parts) were added, and the atmosphere was replaced with nitrogen at 70 ° C for 1 hour while stirring.
Then, the temperature was raised to 70 ° C., the reaction was carried out for 2 hours, the temperature was raised to 80 ° C., the stirring was continued for another hour, and the reaction was terminated by cooling to room temperature to obtain a carboxyl group-containing acrylic polymer.

Preparation Example 2 of Organic Acid-Containing Polymer A carboxyl group-containing acrylic polymer was prepared in the same manner as in Preparation Example 1 of organic acid-containing polymer except that 190 parts of cyclohexyl acrylate was used instead of cyclohexyl methacrylate. Obtained.

Preparation Example 3 of Organic Acid-Containing Polymer A carboxyl group-containing acrylic resin was prepared in the same manner as in Preparation Example 1 of organic acid-containing polymer except that 190 parts of isobornyl acrylate was used instead of cyclohexyl methacrylate. A polymer was obtained.

Preparation Example 4 of Organic Acid-Containing Polymer A carboxyl group-containing acrylic polymer was prepared in the same manner as in Preparation Example 1 of organic acid-containing polymer except that 10 parts of methacrylic acid was used instead of acrylic acid. Obtained.

Preparation Example 5 of Organic Acid-Containing Polymer A carboxyl group-containing polymer was prepared in the same manner as in Preparation Example 1 of organic acid-containing polymer except that the amount of 2-mercaptoethanol used was 6 parts instead of 4 parts. An acrylic polymer was obtained.

(Preparation Example 6 of Organic Acid-Containing Polymer) Carboxylate was prepared in the same manner as in Preparation Example 1 of organic acid-containing polymer except that the amount of 2-mercaptoethanol was changed from 4 parts to 0.1 part. A group-containing acrylic polymer was obtained.

Preparation Example 7 of Organic Acid-Containing Polymer A carboxyl group-containing acrylic resin was prepared in the same manner as in Preparation Example 1 of organic acid-containing polymer except that 190 parts of 2-ethylhexyl acrylate was used instead of cyclohexyl methacrylate. A polymer was obtained.

(Measurement of Molecular Weight) Preparation of Organic Acid-Containing Polymer The carboxyl group-containing acrylic polymers obtained in Preparation Examples 1 to 7 were dried and then tetrahydrofuran (THF) was added.
Was added to prepare a 0.1 wt% THF solution, and the molecular weight (weight average molecular weight: Mw) was measured by GPC (gel permeation chromatography). The measurement results are shown in Table 1. The measurement conditions are as follows. Measurement conditions: Eluent THF, liquid delivery rate 0.5 ml / min,
Column temperature 40 ℃, converted to standard polystyrene

(Measurement of glass transition temperature) The acrylic acid-containing polymers obtained in Preparation Examples 1 to 7 of organic acid-containing polymers were subjected to G ″ with a dynamic viscoelasticity measuring apparatus.
(Loss elastic modulus) was measured, and the peak value was defined as the glass transition temperature (Tg). The measurement results are shown in Table 1.

[0066]

[Table 1]

Example 1 A rosin phenol resin having a softening point of 145 ° C. (trade name “Sumilite Resin PR1260
3) 100 parts of Sumitomo Durez Co., Ltd. and 30 parts of the carboxyl group-containing acrylic polymer obtained in Preparation Example 1 of the organic acid-containing polymer (solid content conversion) were mixed and dissolved, and then 0.5 145 parts by weight of ammonia water was added, and the mixture was stirred at a temperature of 30 ° C. for 1 hour for preliminary emulsification. The obtained preliminary emulsion was high-pressure emulsified at a pressure of 60 MPa with a high-pressure emulsifier (manufactured by BEE) to obtain an emulsion.
Then, the emulsion is charged into a vacuum distillation apparatus at 50 ° C. for 1
Distilled under reduced pressure for 6 hours under the condition of 30 hPa to obtain a solid content of 5
0% by weight of tackifying resin emulsion was obtained.

Example 2 A rosin phenol resin having a softening point of 145 ° C. (trade name “Sumilite Resin PR1260
3 "Sumitomo Durez Co., Ltd. 100 parts and 30 parts of the carboxyl group-containing acrylic polymer obtained in Preparation Example 2 of organic acid-containing polymer (solid content conversion) were mixed and dissolved, and then 0.5 145 parts by weight of ammonia water was added, and the mixture was stirred at a temperature of 30 ° C. for 1 hour for preliminary emulsification. The obtained preliminary emulsion was high-pressure emulsified at a pressure of 60 MPa with a high-pressure emulsifier (manufactured by BEE) to obtain an emulsion.
Then, the emulsion is charged into a vacuum distillation apparatus at 50 ° C. for 1
Distilled under reduced pressure for 6 hours under the condition of 30 hPa to obtain a solid content of 5
0% by weight of tackifying resin emulsion was obtained.

Example 3 A rosin phenol resin having a softening point of 145 ° C. (trade name “Sumilite Resin PR1260”
3 "Sumitomo Durez Co., Ltd. 100 parts and 30 parts of the carboxyl group-containing acrylic polymer obtained in Preparation Example 3 of the organic acid-containing polymer (solid content conversion) were mixed and dissolved, and then 0.5 145 parts by weight of ammonia water was added, and the mixture was stirred at a temperature of 30 ° C. for 1 hour for preliminary emulsification. The obtained preliminary emulsion was high-pressure emulsified at a pressure of 60 MPa with a high-pressure emulsifier (manufactured by BEE) to obtain an emulsion.
Then, the emulsion is charged into a vacuum distillation apparatus at 50 ° C. for 1
Distilled under reduced pressure for 6 hours under the condition of 30 hPa to obtain a solid content of 5
0% by weight of tackifying resin emulsion was obtained.

Example 4 A rosin phenol resin having a softening point of 145 ° C. (trade name “Sumilite Resin PR1260
3 "Sumitomo Durez Co., Ltd. 100 parts and 30 parts of the carboxyl group-containing acrylic polymer (solid content conversion) obtained in Preparation Example 4 of organic acid-containing polymer were mixed and dissolved, and then 0.5 145 parts by weight of ammonia water was added, and the mixture was stirred at a temperature of 30 ° C. for 1 hour for preliminary emulsification. The obtained preliminary emulsion was high-pressure emulsified at a pressure of 60 MPa with a high-pressure emulsifier (manufactured by BEE) to obtain an emulsion.
Then, the emulsion is charged into a vacuum distillation apparatus at 50 ° C. for 1
Distilled under reduced pressure for 6 hours under the condition of 30 hPa to obtain a solid content of 5
0% by weight of tackifying resin emulsion was obtained.

Example 5 A rosin phenol resin having a softening point of 145 ° C. (trade name “Sumilite Resin PR1260”
3 "Sumitomo Durez Co., Ltd. 100 parts and 30 parts of the carboxyl group-containing acrylic polymer obtained in Preparation Example 5 of organic acid-containing polymer (solid content conversion) were mixed and dissolved, and then 0.5 145 parts by weight of ammonia water was added, and the mixture was stirred at a temperature of 30 ° C. for 1 hour for preliminary emulsification. The obtained preliminary emulsion was high-pressure emulsified at a pressure of 60 MPa with a high-pressure emulsifier (manufactured by BEE) to obtain an emulsion.
Then, the emulsion is charged into a vacuum distillation apparatus at 50 ° C. for 1
Distilled under reduced pressure for 6 hours under the condition of 30 hPa to obtain a solid content of 5
0% by weight of tackifying resin emulsion was obtained.

Example 6 100 parts of polymerized rosin ester having a softening point of 125 ° C. (trade name “Pencel D125” manufactured by Arakawa Chemical Industry Co., Ltd.) and Preparation Example 1 of polymer containing organic acid
After mixing and dissolving 30 parts (as solid content) of the carboxyl group-containing acrylic polymer obtained by
Add 145 parts of 5 wt% ammonia water, and heat at 30 ° C.
The mixture was stirred for 1 hour and pre-emulsified. The obtained pre-emulsion is 60 MPa by a high pressure emulsifying machine (manufactured by BEE).
High pressure emulsification was performed at a pressure of 1 to obtain an emulsion. Next, the emulsion was charged in a vacuum distillation apparatus and vacuum distillation was performed for 6 hours under the conditions of 50 ° C. and 130 hPa to obtain a tackifying resin emulsion having a solid content of 50% by weight.

(Example 7) Obtained by 100 parts of disproportionated rosin ester (trade name "Super Ester A-100" manufactured by Arakawa Chemical Industry Co., Ltd.) having a softening point of 100 ° C and Preparation Example 1 of an organic acid-containing polymer. After mixing and dissolving 30 parts (based on solid content) of the obtained carboxyl group-containing acrylic polymer, 145 parts of 0.5 wt% ammonia water was added,
Preliminary emulsification was performed by stirring at a temperature of 30 ° C for 1 hour. The preliminarily obtained emulsion was treated with a high pressure emulsifier (manufactured by BEE Co.).
High pressure emulsification was performed at a pressure of 60 MPa to obtain an emulsion. Next, the reduced pressure distillation apparatus was charged with the emulsion to 50 ° C. and 130
Vacuum distillation was carried out for 6 hours under the condition of hPa to obtain a tackifying resin emulsion having a solid content of 50% by weight.

(Example 8) 100 parts of a terpene phenol resin (trade name "YS Polystar T-115" manufactured by Yasuhara Chemical Co., Ltd.) having a softening point of 115 ° C, and a carboxyl group obtained in Preparation Example 1 of an organic acid-containing polymer After mixing and dissolving 30 parts (containing solid content) of the contained acrylic polymer, 145 parts of 0.5 wt% ammonia water was added, and preliminarily emulsified by stirring at a temperature of 30 ° C. for 1 hour. The obtained preliminary emulsion was high-pressure emulsified at a pressure of 60 MPa with a high-pressure emulsifier (manufactured by BEE) to obtain an emulsion. Then, the emulsion is charged into a vacuum distillation apparatus at 50 ° C. for 13
Distilled under reduced pressure for 6 hours under the condition of 0 hPa to obtain a solid content of 50
A weight percent tackifying resin emulsion was obtained.

Example 9 A rosin phenol resin having a softening point of 145 ° C. (trade name “Sumilite Resin PR1260”
3) 100 parts of Sumitomo Durez Co., Ltd. and 10 parts of the carboxyl group-containing acrylic polymer obtained in Preparation Example 1 of organic acid-containing polymer (solid content conversion) were mixed and dissolved, and then 0.5 115 parts by weight of ammonia water was added, and the mixture was stirred at a temperature of 30 ° C. for 1 hour for preliminary emulsification. The obtained preliminary emulsion was high-pressure emulsified at a pressure of 60 MPa with a high-pressure emulsifier (manufactured by BEE) to obtain an emulsion.
Then, the emulsion is charged into a vacuum distillation apparatus at 50 ° C. for 1
Distilled under reduced pressure for 6 hours under the condition of 30 hPa to obtain a solid content of 5
0% by weight of tackifying resin emulsion was obtained.

Example 10 A rosin phenol resin having a softening point of 145 ° C. (trade name “Sumilite Resin PR1260”
3 "Sumitomo Durez Co., Ltd. 100 parts and 50 parts of the carboxyl group-containing acrylic polymer obtained in Preparation Example 1 of organic acid-containing polymer (solid content conversion) were mixed and dissolved, and then 0.5 115 parts by weight of ammonia water was added, and the mixture was stirred at a temperature of 30 ° C. for 1 hour for preliminary emulsification. The obtained preliminary emulsion was high-pressure emulsified at a pressure of 60 MPa with a high-pressure emulsifier (manufactured by BEE) to obtain an emulsion.
Then, the emulsion is charged into a vacuum distillation apparatus at 50 ° C. for 1
Distilled under reduced pressure for 6 hours under the condition of 30 hPa to obtain a solid content of 5
0% by weight of tackifying resin emulsion was obtained.

Comparative Example 1 A rosin phenol resin having a softening point of 145 ° C. (trade name “Sumilite Resin PR1260
3) 100 parts of Sumitomo Durez Co., Ltd. and 30 parts of the carboxyl group-containing acrylic polymer obtained in Preparation Example 6 of the organic acid-containing polymer (solid content conversion) were mixed and dissolved, and then 0.5 wt. % 145 parts of ammonia water was added, and the mixture was stirred at a temperature of 30 ° C. for 1 hour to carry out preliminary emulsification. The obtained preliminary emulsion was high-pressure emulsified at a pressure of 60 MPa with a high-pressure emulsifier (manufactured by BEE) to obtain an emulsion. Then, the emulsion is charged into a vacuum distillation apparatus at 50 ° C. for 13
Distilled under reduced pressure for 6 hours under the condition of 0 hPa to obtain a solid content of 50
A weight percent tackifying resin emulsion was obtained.

(Comparative Example 2) A rosin phenol resin having a softening point of 145 ° C. (trade name "Sumilite Resin PR1260"
3 "Sumitomo Dures Co., Ltd.) 100 parts and the carboxyl group-containing acrylic polymer 30 parts (solid content conversion) obtained in Preparation Example 7 of organic acid-containing polymer were mixed and dissolved, and then 0.5 weight % 145 parts of ammonia water was added, and the mixture was stirred at a temperature of 30 ° C. for 1 hour to carry out preliminary emulsification. The obtained preliminary emulsion was high-pressure emulsified at a pressure of 60 MPa with a high-pressure emulsifier (manufactured by BEE) to obtain an emulsion. Then, the emulsion is charged into a vacuum distillation apparatus at 50 ° C. for 13
Distilled under reduced pressure for 6 hours under the condition of 0 hPa to obtain a solid content of 50
A weight percent tackifying resin emulsion was obtained.

COMPARATIVE EXAMPLE 3 A rosin phenol resin having a softening point of 145 ° C. (trade name “Sumilite Resin PR1260”
3 "100 parts of Sumitomo Durez Co., Ltd. was dissolved in 60 parts of toluene, and then 3 parts of an anionic emulsifier (polyoxyethylene ammonium lauryl sulfate) and 110 parts of 0.5% by weight ammonia water were added, and the temperature was adjusted to 30. Preliminary emulsification was performed by stirring at 1 ° C for 1 hour. The obtained preliminary emulsion was high-pressure emulsified at a pressure of 60 MPa with a high-pressure emulsifier (manufactured by BEE) to obtain an emulsion. Next, the emulsion was charged in a vacuum distillation apparatus and vacuum distillation was performed for 6 hours under the conditions of 50 ° C. and 130 hPa to obtain a tackifying resin emulsion having a solid content of 50% by weight.

(Evaluation Method) Examples 1 to 10 and Comparative Example 1
The tackifying resin emulsions obtained in any of 3 to 3 were mixed with a water-based pressure-sensitive adhesive, and the performance evaluation as a water-based pressure-sensitive adhesive composition was examined by the following method. Specifically, 100 parts of the acrylic water-based pressure-sensitive adhesive (acrylic emulsion polymer) obtained in Preparation Example 1 of water-based acrylic pressure-sensitive adhesive was added to the tackifying resin obtained in Examples and Comparative Examples. The preparation prepared by mixing 30 parts of the emulsion was thickened with aqueous ammonia to obtain an aqueous pressure-sensitive adhesive composition. In Comparative Example 4, an aqueous pressure-sensitive adhesive composition containing no tackifying resin emulsion was mixed, and in Comparative Example 5, 100 parts of the tackifying resin emulsion obtained in Example 1 was mixed. It was set as the agent composition. These water-based pressure-sensitive adhesive compositions were applied on a paper base release paper having a thickness of 150 μm, and dried at 120 ° C. for 3 minutes,
A pressure-sensitive adhesive layer having a thickness of 70 μm was formed. This pressure-sensitive adhesive layer was attached to both sides of a rayon-pulp non-woven fabric having a basis weight of 14 g to prepare a pressure-sensitive adhesive tape, and various tests were conducted by the following performance evaluation methods. The evaluation results are shown in Tables 2-3.

(Adhesive Strength) A PET (polyethylene terephthalate) film having a thickness of 38 μm is attached to one surface of a pressure-sensitive adhesive tape having a width of 20 mm, and the tape is pressure-bonded to various adherends by reciprocating a 2 kg rubber roller once. After leaving it for 30 minutes, it was peeled off at a peeling speed of 300 mm / min, and the adhesive force (N / 20 mm width) to each adherend was measured.
As the adherend, a stainless plate (SUS plate) or polypropylene plate (PP plate) was used.

(Holding power) An adhesive tape having a width of 10 mm was attached to a Bakelite plate with a contact area of 10 mm × 20 mm, and after 20 minutes, the Bakelite plate was hung down and a uniform load of 500 g was applied to the free end of the adhesive tape. Then, at 40 ° C. or 80 ° C., the distance (mm) at which the pressure-sensitive adhesive sheet was displaced was measured after 1 hour.

(Repulsion resistance test) A pressure-sensitive adhesive tape having a diameter of 30
After being attached to the outer surface side of an aluminum plate (10 mm × 50 mm) having a thickness of 0.5 mm, which was bent in an arc shape so as to have a thickness of mm, it was attached to a polypropylene plate with a laminator. After this was left at room temperature for 24 hours, the peeled height (mm) of the end of the polypropylene plate was measured.

(Constant load peelability test) width 20 mm × length 1
A PET film with a thickness of 38 μm is attached to a 00 mm adhesive tape, the tape is adhered to the adherend by reciprocating a 2 kg rubber roller once, and left for 30 minutes, and then a uniform load of 100 g is applied to the free end of the adhesive tape. The peeling distance (m
m) was measured. A polypropylene plate (PP plate) and a polystyrene plate (PSt plate) were used as the adherends.

(Whitening resistance test) width 50 mm x length 50 m
m pressure sensitive adhesive tape with a 38 μm PET film attached to one side, the pressure sensitive adhesive surface was dipped in water, and the whitening state after 12 hours was visually observed.
The whitening resistance was evaluated as x.

[0086]

[Table 2]

[0087]

[Table 3]

As is clear from Tables 2 and 3, the water-based pressure-sensitive adhesive compositions containing the tackifying resin emulsions according to the Examples have excellent adhesive strength, holding power, repulsion resistance and constant load peelability. In addition, whitening is less likely to occur. In contrast, Comparative Example 1 uses a high-molecular-weight carboxyl group-containing acrylic polymer, and thus is particularly inferior in resilience resistance and constant load peeling property. In Comparative Example 2, a carboxyl group having a low glass transition temperature is used. Since the contained acrylic polymer is used, it is inferior particularly in the holding power, the repulsion resistance and the constant load peeling property. Further, in Comparative Example 3, the anionic emulsifier is used without using the carboxyl group-containing acrylic polymer, so that the whitening resistance is particularly poor. Furthermore, in Comparative Example 4, since the tackifying resin emulsion is not used, the adhesive strength, the repulsion resistance and the constant load peeling property are particularly poor. In Comparative Example 5, only the tackifying resin emulsion is used. It is inferior in terms of adhesive strength, holding power, resistance to repulsion and peeling under constant load.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tomoya Naito             Nitto 1-2, Shimohozumi, Ibaraki City, Osaka Prefecture             Electric Works Co., Ltd. F-term (reference) 4J002 AF02W BA01W BG01X BG04X                       BG05Y BK00W CC03W CC10W                       DE026 GJ01 HA07                 4J040 BA172 BA201 DF041 DF051                       DN032 EB052 EL032 GA07                       GA25 GA28 JB09 LA07 MA10

Claims (6)

[Claims] 1. The tackifying resin (A1) has a glass transition temperature (Tg) of 10 ° C. or higher and a weight average molecular weight of 300 to.
A tackifying resin emulsion, which is 50,000 and is dispersed in water by a polymer (A2) containing an organic acid group in the molecule. 2. The tackifying resin emulsion according to claim 1, wherein the polymer (A2) is an acrylic polymer containing a (meth) acrylic acid ester as a monomer main component. 3. The tackifying resin emulsion according to claim 1, wherein the organic acid group of the polymer (A2) is a carboxylic acid group. 4. The tackifying resin (A1) has a glass transition temperature (Tg) of 10 ° C. or higher and a weight average molecular weight of 300 to.
A method for producing a tackifying resin emulsion, which is 50,000 and is dispersed in water using a polymer (A2) containing an organic acid group in the molecule. 5. The tackifying resin emulsion (A) according to claim 1, and an acrylic polymer (B).
A water-based pressure-sensitive adhesive composition containing a pressure-sensitive adhesive (B) containing 1) as a base polymer. 6. The water-based pressure-sensitive adhesive composition according to claim 5, wherein 1 to 50 parts by weight of the tackifying resin emulsion (A) is mixed with 100 parts by weight of the pressure-sensitive adhesive (B).