JP2001011146A - Water dispersion of tackiness-imparting resin, its production and water dispersion type pressure sensitive adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water dispersion produced by dispersing a tackiness-imparting resin in water without using any emulsifying agent and useful as a blending agent for a water dispersion type pressure sensitive adhesive. SOLUTION: This water dispersion obtained by dispersing a tackiness-imparting resin together with a polyisocyanate, is produced by mixing a polyol component with the tackiness-imparting resin, reacting the mixture with a polyisocyanate component, neutralizing carboxyl groups incorporated in the polyol component for dispersing in water and dispersing the neutralized product into water and performing a main chain extension by the reaction of the residual isocyanate groups. Or, the water dispersion obtained by dispersing the tackiness-imparting resin together with a urethane polymer and an acrylic polymer, is obtained by reacting the polyol component with the polyisocyanate component, adding the tackiness-imparting resin dissolved with an acrylic monomer to the product, neutralizing the carboxyl groups incorporated in the polyol component for dispersing in water and performing the main chain extension by the reaction of the residual isocyanate groups and the polymerization of the acrylic monomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aqueous dispersion of a tackifier resin, a method for producing the same, and an aqueous dispersion-type pressure-sensitive adhesive composition containing the above aqueous dispersion.

[0002]

2. Description of the Related Art A pressure-sensitive adhesive comprises a pressure-sensitive adhesive polymer composed of an acrylic polymer or a natural rubber as a main component and a tackifying resin or a cross-linking agent. Is usually applied to various supports and dried to obtain pressure-sensitive adhesive sheets, which are used in many fields. In recent years, due to an increase in environmental problems, a water-dispersed pressure-sensitive adhesive that does not use an organic solvent is frequently used.

[0003] In such a water-dispersed pressure-sensitive adhesive, the tackifier resin to be added for improving the adhesive force must be an aqueous dispersion like the pressure-sensitive adhesive polymer.
To make the tackifier resin an aqueous dispersion, a method of dissolving the tackifier resin in an organic solvent and dispersing the same in water using an emulsifier, a method of further removing the organic solvent in water, and melting the tackifier resin Numerous methods have been proposed and put into practical use, such as a method of dispersing the same in water using an emulsifier, a method of dissolving a tackifier resin in a monomer, and emulsifying and polymerizing the same to incorporate the tackifier resin into polymer particles. I have.

[0004]

However, any of these methods requires a method of dispersing the tackifier resin stably in water.
It is necessary to use an emulsifier, and further, it is necessary to select an optimum emulsifier according to the type of the tackifying resin, the type of the pressure-sensitive adhesive polymer, and the desired adhesive properties. The selection of such an emulsifier is troublesome, and the use of the emulsifier has a problem that the water resistance of the pressure-sensitive adhesive containing the tackifier resin is adversely affected. In particular, recently, in water-dispersed pressure-sensitive adhesives, various attempts have been made to improve the water resistance by reducing the use of emulsifiers. For such water-dispersed pressure-sensitive adhesives, an emulsifier was used. When the aqueous dispersion of the tackifier resin is blended, the effect of improving the water resistance of the water-dispersed pressure-sensitive adhesive is lost.

In view of such circumstances, the present invention provides an aqueous dispersion in which a tackifying resin is stably dispersed in water without using an emulsifier, and a water-dispersion type obtained by blending the same with excellent adhesive properties and water resistance. It is intended to obtain a pressure-sensitive adhesive composition.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, urethane dispersed stably in water by reacting a polyol component and a polyisocyanate component. When the polymer is produced, or when an acrylic monomer is further added to such a urethane reaction system and the acrylic monomer is polymerized to form an acrylic polymer simultaneously with the urethane polymer, the above-mentioned polyol component is used. If the tackifying resin is mixed in the acrylic monomer or the tackifying resin is dissolved in the acrylic monomer, the urethane polymer acts as a stabilizer for dispersing the tackifying resin in water. As a result, an aqueous dispersion in which the tackifier resin is stably dispersed in water together with a urethane polymer or an acrylic polymer without using an emulsifier is obtained. By mixing this aqueous dispersion of the tackifying resin with an aqueous dispersion containing a pressure-sensitive adhesive polymer as a main component, it has excellent adhesive properties and does not use an emulsifier. The inventors have found that an excellent water-dispersed pressure-sensitive adhesive composition can be obtained, and have completed the present invention.

According to the present invention, a tackifier resin is dispersed in water together with a urethane polymer comprising a polyol component and a polyisocyanate component or an acrylic polymer, and the tackifier resin is contained in a solid content. 40 to 90% by weight, 5 to 50% by weight of a polyol component, 1 to 20% by weight of a polyisocyanate component, 0 to 2 of an acrylic polymer
Water dispersion of a tackifying resin (claim 1), wherein the polyol component is a polyether
The present invention relates to the above aqueous dispersion comprising terpolyol, polyester polyol, acrylic polyol or a mixture thereof (claim 2). Also, the present invention provides a water-dispersed pressure-sensitive adhesive composition comprising a water-dispersed resin having the above-mentioned composition and an aqueous dispersion containing a pressure-sensitive adhesive polymer as a main component. According to claim 5).

Further, the present invention provides a method for producing an aqueous dispersion of the tackifier resin having the above constitution, wherein the tackifier resin is mixed with a polyol component, and the resulting mixture is reacted with a polyisocyanate component. The carboxyl group contained in the component is neutralized and dispersed in water, the main chain is extended by the reaction of the remaining isocyanate group, and an aqueous dispersion in which the tackifying resin is dispersed in water together with the urethane polymer. The present invention relates to a method for producing an aqueous dispersion of a tackifying resin (claim 3), wherein a polyisocyanate component is reacted with a polyol component and dissolved in an acrylic monomer. A tackifier resin is added, the carboxyl groups contained in the above-mentioned polyol component are neutralized and dispersed in water, the main chain is extended by the reaction of the remaining isocyanate groups, and the weight of the acrylic monomer is increased. To obtain an aqueous dispersion in which the tackifier resin is dispersed in water together with urethane polymer and acrylic polymer (claim 4). is there.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Tackifying resins in the present invention include rosin-based, modified rosin-based, rosin ester-based, terpene-based, terpene phenol-based, petroleum resin-based, cumarone-indene-based, styrene-based and xylene-based resins. Any known tackifying resin can be used. The softening point of the tackifier resin is not particularly limited, and can be appropriately determined depending on the intended adhesive properties of the water-dispersed pressure-sensitive adhesive to be compounded. In general, an adhesive having a softening point of 70 to 160 ° C. An application resin is preferably used.

The polyol component in the present invention has at least two hydroxyl groups in one molecule, and is mainly composed of polyether polyol, polyester polyol, acryl polyol or a mixture thereof. Are preferred. The polyether polyol and polyester polyol preferably have a number average molecular weight of 500 to 4,000. If the molecular weight is too small, the urethane hard segment will increase, and the resulting polymer as a stabilizer will be too hard, easily reducing the inherent effect of the tackifier resin.If the molecular weight is too large, the dispersibility in water will be poor. Inferior.

[0011] Polyether polyols include ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, and hexamethylene glycol.
Low-molecular-weight polyols such as divalent alcohols such as alcohol, trimethylolpropane, glycerin, pentaerythritol and the like, and addition polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, etc. Things are used. Examples of the polyester polyol include the above-mentioned divalent alcohols and alcohols such as dipropylene glycol, 1,4-butanediol, 1,6-hexanediol and neopentyl glycol.
And adipic acid, azelaic acid, sebacic acid, etc.
Those obtained by polycondensation with a basic acid are used.

When the above-mentioned polyetherpolyol or polyesterpolyol is used as the main component of the polyol component, other components are used to neutralize and disperse in water after the reaction with the polyisocyanate component. As a polyol component,
A carboxyl group-containing polyol such as 2,2-dimethylolpropionic acid, 2,2-dimethylolacetic acid, or 2,2-dimethylolbutyric acid is used in combination. In general, it is desirable to add such a carboxyl group-containing polyol by dissolving it in a polar solvent such as N-methylpyrrolidone from the viewpoint of solubility and reactivity with other components.

[0013] Acrylic polyols usually have a molecular weight of 0.1.
It has a hydroxyl group of 0.0005 to 0.0007 equivalent / g and usually also has a carboxyl group of 0.0007 to 0.003 equivalent / g, and has a number average molecular weight of usually 3,000.
Acrylate oligomers or polymers of up to 20,000, having the above-mentioned hydroxyl group in the molecule, are reacted with the polyisocyanate component to form urethane polymer.
Is constituted. That is, the acrylic polyol is one of the polyol components used for forming the urethane polymer, and is different from the acrylic polymer described below, which does not constitute the urethane polymer.

The acrylic polyol can be used alone, but usually it is desirable to use it as a mixture with a polyether polyol or a polyester polyol. In this case, from the viewpoint of water dispersibility after the reaction with the polyisocyanate component and its stability, the polyether polyol or polyester polyol is 20 to 80% by weight, and the acrylic polyol is 80 to 20% by weight. It is better to be. Acrylic polyol contains a carboxyl group in the molecule, and it is not particularly necessary to use the above-mentioned carboxyl group-containing polyol in combination for neutralization and water dispersion.

Acrylic polyol is an acrylic monomer.
A monomer mixture obtained by adding a monomer having a carboxyl group or a monomer having a hydroxyl group to a monomer mixture, using a polymerization initiator and a chain transfer agent having a hydroxyl group, is subjected to a polymerization reaction in a conventional manner to obtain a monomer mixture. Can be When a mixture of acrylic polyol and the above-mentioned polyether polyol is used, the polymerization reaction of the above monomer mixture may be carried out in the presence of the polyether polyol or the like. In this case, it is preferable that a part of the formed acrylic polyol is grafted onto the polyether polyol or the like, so that the compatibility with the polyether polyol is improved and the polymerization reaction is moderated.

The acrylic monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, and hexyl (meth) acrylate. , 2-ethylhexyl (meth) acrylate, (meth)
Alkyl (meth) acrylates such as octyl acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate and isononyl (meth) acrylate are used. Together with these esters, 5% of all monomers
Within a range not exceeding 0% by weight, vinyl acetate, vinyl propionate, styrene and its derivatives, (meth) acrylamide, mono- or diesters of maleic acid, N-methylo-
(Meth) acrylamide, glycidyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, oligoester (meth) acrylate, ε
-Other monomers such as caprolactone (meth) acrylate may be used in combination.

As the monomer having a carboxyl group,
(Meth) acrylic acid, maleic acid, itaconic acid and the like are used. Further, as the monomer having a hydroxyl group, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate and the like can be used. Further, as the polymerization initiator, an azo-based polymerization initiator such as 2,2-azobisisopronitrile or a peroxide-based polymerization initiator such as benzoyl peroxide is used. Examples of the chain transfer agent having a hydroxyl group include 2-mercaptoethanol and 1-mercapto-2-propanol.
, 3-mercapto-1-propanol, p-mercaptophenol, and the like.

The amount of the monomer having a carboxyl group is determined so that the amount of the carboxyl group of the acrylic polyol falls within the above range. If the amount of the carboxyl group of the acrylic polyol is too small, the dispersibility in water will be poor, and if it is too large, it will only absorb water and will not disperse. The amount of the monomer having a hydroxyl group or the chain transfer agent having a hydroxyl group is determined so that the amount of the hydroxyl group in the acrylic polyol falls within the above range. If the amount of the hydroxyl group in the acrylic polyol is too small, the reactivity with the polyisocyanate component will be poor, and the physical properties of the produced polymer will be difficult to stabilize.

When a chain transfer agent having a hydroxyl group is used, a hydroxyl group can be introduced into the molecular end of the acrylic polyol, and as a result, it reacts with the polyisocyanate component to form a urethane polymer having higher molecular weight and excellent physical properties. Can be generated, which is desirable. Further, by appropriately selecting the amount of the chain transfer agent having a hydroxyl group together with the amount of the polymerization initiator to be used, the number average molecular weight of the acrylic polyol can be easily set so as to be within the above range. If the molecular weight of the acrylic polyol is too small, the urethane polymer acting as a stabilizer becomes too hard to easily reduce the inherent effect of the tackifier resin, and if it is too large, the dispersibility in water is poor, which is not preferable.

As the polyisocyanate component in the present invention, any aromatic, aliphatic or alicyclic polyisocyanate can be used. Isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, cyclohexane-1,4-diisocyanate, etc., from the viewpoint of prompt reaction with the polyol component and suppression of the reaction with water. It is particularly preferable to use the alicyclic polyisocyanate of the above. The polyisocyanate component is preferably a diisocyanate as described above, but if necessary,
Tri- or higher polyisocyanates can also be used.

As described above, the acrylic polymer in the present invention means a homopolymer or copolymer of an acrylic monomer which does not participate in the urethanization reaction with the polyisocyanate component. Here, as the acrylic monomer, an alkyl (meth) acrylate similar to that described as a raw material component of the acrylic polyol is used as a main component, and together with this alkyl ester, if necessary, 50% by weight of all monomers. %, Other monomers such as vinyl acetate described as one of the raw material components may be used. Further, the above-mentioned monomer having a carboxyl group and the monomer having a hydroxyl group can be used in combination.

In the present invention, the above-mentioned tackifying resin is prepared by using the urethane polymer comprising the above-mentioned polyol component and polyisocyanate component without using an emulsifier.
Alternatively, together with this and the above-mentioned acrylic polymer, they are uniformly dispersed in water to form an aqueous dispersion of a tackifier resin. Here, the amount of each component used is
In the solid content of the aqueous dispersion, the tackifier resin is 40 to 90% by weight, preferably 45 to 80% by weight, and the polyol component is 5 to 50% by weight.
-50% by weight, preferably 10-40% by weight, and the polyisocyanate component is 1-20% by weight, preferably 2-15% by weight.
% By weight, and 0 to 20% by weight, preferably 0 to 15% by weight of the acrylic polymer. If the tackifier resin is less than 40% by weight and the polyol component exceeds 50% by weight, the polyisocyanate component exceeds 20% by weight, or the acrylic polymer exceeds 20% by weight, the adhesion may occur. The effect of improving characteristics is poor. Conversely, when the amount of the tackifier resin exceeds 90% by weight, the polyol component becomes 5%.
If the content is less than 1% by weight and the content of the polyisocyanate component is less than 1% by weight, the stability of the aqueous dispersion tends to be poor.

In the present invention, the aqueous dispersion of the tackifying resin having the above constitution is used when the polyol component and the polyisocyanate component are reacted to form a urethane polymer stably dispersed in water. A method in which a tackifier resin is mixed with the polyol component, an acrylic monomer is added to the urethane reaction system, and the acrylic monomer is polymerized to form an acrylic polymer together with the urethane polymer. It can be produced by a method in which a tackifier resin is dissolved in a monomer. If necessary, the above methods can be combined to mix the tackifier resin with the polyol component and dissolve the tackifier resin in the acrylic monomer to easily increase the concentration of the tackifier resin in the aqueous dispersion. Can also be increased.

In the above method, a tackifier resin is mixed with a polyol component, a polyisocyanate component is reacted with the mixture, and the carboxyl groups contained in the polyol component are neutralized and dispersed in water. The main chain is extended by the reaction of the remaining isocyanate group to produce an aqueous dispersion in which the tackifier resin is uniformly and stably dispersed in water together with the urethane polymer. As described above, the above-mentioned polyol component containing a carboxyl group usually contains an appropriate amount of a carboxyl group-containing polyol (for example, 2,2-dimethylolpropione) in a polyetherpolyol or a polyesterpolyol. Acid or the like, or a mixture of polyetherpolyol or polyesterpolyol and acrylpolyol (containing a carboxyl group).

When mixing the tackifier resin with such a polyol component, heat treatment or the like is performed to uniformly mix both components. When the polyisocyanate component is reacted after this mixing, dibutyltin dilaurate, tin octoate, 1,4-diazabicyclo (2,2,2) may be used as a reaction catalyst for the isocyanate group and the hydroxyl group. Octane can be used. The amount of the polyisocyanate component used is
The equivalent ratio (NCO /
OH ratio) is in the range of 2 to 9, especially when the polyol component is a mixture of a polyether polyol or a polyester polyol and an acrylic polyol, the equivalent ratio is 2 to 9.
5, and more preferably in the range of 2.1 to 3.0. If the amount of the polyisocyanate component is too small, the main chain elongates at this stage, resulting in a high viscosity, which makes it difficult to disperse in water stably.On the contrary, if it is too large, the residual amount of the unreacted polyisocyanate component increases, and tackiness is imparted. The effect of improving the adhesive properties by blending the resin is reduced.

By the above reaction, a prepolymer in which free isocyanate groups remain, that is, a urethane prepolymer is formed, and a homogeneous mixture of the prepolymer and a tackifying resin is formed. Neutralize carboxyl groups derived from the water component and disperse in water.
Triethylamine, ammonia, or the like is used as a base for neutralization. Dispersion in water may be carried out by adding water to the above-mentioned neutralized mixture or, conversely, by adding the above-mentioned neutralized mixture to water. It is desirable to do. After this aqueous dispersion, the main chain is extended by the reaction of the isocyanate group remaining in the prepolymer to produce a high molecular weight urethane polymer, and the tackifier resin is uniformly and stably dispersed in water together with the urethane polymer. A dispersed water dispersion is obtained. In the above-mentioned main chain elongation, it is desirable to use a polyamine such as ethylenediamine or propylenediamine at a ratio equivalent to the remaining isocyanate group for the reaction.

In the above method, a polyol component is reacted with a polyisocyanate component, and a tackifier resin dissolved in an acrylic monomer is added thereto.
The carboxyl groups contained in the water component are neutralized and dispersed in water, the main chain is extended by the reaction of the remaining isocyanate groups and the acrylic monomer is polymerized, and the tackifying resin is converted into a urethane polymer and an acrylic polymer. And to produce an aqueous dispersion dispersed in water. Also in this method, a polyol component containing a carboxyl group usually contains an appropriate amount of a carboxyl group-containing polyol (for example, 2,2-dimethylol) in a polyether polyol or a polyester polyol. Or a mixture of a polyether polyol or a polyester polyol and an acrylic polyol (containing a carboxyl group).

A polyisocyanate component is reacted with such a polyol component in the same manner as described above to produce a urethane prepolymer. In this prepolymer,
Add tackifying resin dissolved in acrylic monomer,
Mix evenly. Then, the carboxyl group derived from the polyol component contained in the prepolymer is neutralized and dispersed in water. Neutralization and aqueous dispersion can be performed in the same manner as in the above method. After dispersion in water, the main chain is extended by the reaction of the isocyanate group remaining in the prepolymer, and the acrylic monomer is polymerized to obtain a high molecular weight urethane polymer.
And an acrylic polymer, an aqueous dispersion in which the tackifier resin is uniformly and stably dispersed in water together with the urethane polymer and the acrylic polymer is obtained. The extension of the main chain can be carried out in the same manner as described above, and the polymerization can be carried out by adding a polymerization initiator to the reaction system and subjecting it to a reaction treatment.
As the polymerization initiator, a peroxide such as ammonium persulfate or a water-soluble azo compound is used. It is particularly preferable to use an azo compound which does not generate an ion product in water. When an oil-soluble polymerization initiator is used, it may be mixed in an acrylic monomer in advance.

The aqueous dispersion of the tackifying resin thus obtained can be prepared by using the tackifying resin, the polyol component, the polyisocyanate component and the acrylic polymer within the above-mentioned predetermined ranges, respectively. Can be handled as a stable aqueous dispersion even though no water is used. For this reason, in the present invention, such an aqueous dispersion of a tackifying resin is used as a pressure-sensitive adhesive polymer.
Is mixed with an aqueous dispersion containing as a main component, a water-dispersed pressure-sensitive adhesive composition having excellent adhesive properties and excellent water resistance can be produced.

An aqueous dispersion containing a pressure-sensitive adhesive polymer as a main component is a water-dispersible pressure-sensitive adhesive containing an acrylic polymer or natural rubber obtained by an emulsion polymerization method, in particular, an improvement in water resistance. For this reason, the above-mentioned adhesive in which the amount of the emulsifier used is reduced is preferable. An emulsifier-free water-dispersion type containing a urethane polymer or an acrylic polymer obtained by the same method as described above or a method analogous thereto (Reference Example 1) except that no tackifier resin is used. Pressure sensitive adhesives are preferably used.

[0031]

The present invention will be described more specifically with reference to the following examples. In the following, “parts” means “parts by weight”.

Example 1 Polypropylene glycol (number average molecular weight: 4,000)
To 100 parts, 120 parts of a terpene phenol resin having a softening point of 112 ° C. was added as a tackifier resin, and the mixture was heated to 120 ° C. to make a uniform state. In addition, N-methylpyrrolidone 2
Add 8 parts of dimethylolpropionic acid dissolved in 0 parts,
Water was removed by heating to 100 ° C. for degassing. 4,4'-
26 parts of dicyclohexylmethane diisocyanate was added, and 0.03 part of dibutyltin dilaurate was further added. The mixture was reacted at 65 ° C. for 3 hours to convert the polyol component into isocyanate. Thereafter, 3 parts of triethylamine was added and stirred to carry out a carboxyl group neutralization reaction. To this, 480 parts of distilled water was added and dispersed. Further, 1 part of ethylenediamine was diluted three times with distilled water and added, and the main chain was extended by the reaction of the remaining isocyanate group.

Thus, an aqueous dispersion was obtained in which a terpene phenol resin having a softening point of 112 ° C. as a tackifying resin was stably dispersed in water together with a urethane polymer without using an emulsifier. The aqueous dispersion of the tackifier resin contained 46.5% by weight of a tackifier resin (terpene phenol resin having a softening point of 112 ° C.), 41.9% by weight of a polyol component, and a polyisocyanate component in a solid content. 10% by weight (the remaining components include a neutralizing agent and a main chain extender of urethane).

Example 2 Polypropylene glycol (number average molecular weight: 4,000)
To 100 parts, 8 parts of dimethylolpropionic acid dissolved in 20 parts of N-methylpyrrolidone was added, and the mixture was heated and degassed at 100 ° C. to remove water. 26 parts of 4,4'-dicyclohexylmethane diisocyanate was added, and 0.03 part of dibutyltin dilaurate was further added. The mixture was reacted at 65 ° C. for 3 hours to convert the polyol component into isocyanate. I got it. In addition, 37.5 parts of butyl acrylate had a softening point of 112.
A solution prepared by uniformly dissolving 150 parts of a terpene phenol resin at 150 ° C. was added, and the whole was uniformly stirred. Thereafter, 3 parts of triethylamine was added and stirred to carry out a carboxyl group neutralization reaction. Put 700 parts of distilled water in another flask,
After purging with nitrogen for 1.5 hours, the above neutralized product was added dropwise to the mixture by a dropping funnel and subjected to dispersion treatment. To this, 1 part of ethylenediamine was diluted three times with distilled water, and 0.02 part of azobisisobutylvaleronitrile was further added. The mixture was heated at 60 ° C. and reacted for 2 hours to carry out main chain extension and polymerization. I got it.

Thus, an aqueous dispersion in which a terpene phenol resin having a softening point of 112 ° C. as a tackifying resin is stably dispersed in water together with a urethane polymer and an acrylic polymer without using an emulsifier. I got
The aqueous dispersion of the tackifier resin contained 4% tackifier resin (terpene phenol resin having a softening point of 112 ° C.) in the solid content.
6.1% by weight, 33.2% by weight of a polyol component, 8% by weight of a polyisocyanate component, 1% of an acrylic polymer
1% by weight (the remaining components include a neutralizing agent and a main chain extender of urethane).

Example 3 Polytetramethylene glycol (number average molecular weight: 3,000
0, hydroxyl group 0.00067 equivalent / g) in the presence of 50 parts, 25 parts of butyl acrylate, 20 parts of ethyl acrylate
, A monomer mixture consisting of 4.5 parts of acrylic acid and 0.5 part of 2-hydroxyethyl acrylate was converted to 2-mercaptoethanol 1 as a chain transfer agent having a hydroxyl group.
Parts, and 0.05 parts of 2,2-azobisisobutyronitrile as a polymerization initiator, a polymerization reaction was carried out at 50 ° C. for 6 hours under a nitrogen stream. In this way, the number average molecular weight 3,
000 polytetramethylene glycol, a carboxyl group of 0.0012 equivalent / g and a hydroxyl group of 0.00033
A viscous liquid consisting of a mixture with an acrylic polyol having an equivalent weight / g and a number average molecular weight of 7,400 was obtained. The measurement of the number average molecular weight and the like was performed by GPC.

The viscous liquid was heated to 100 ° C. and subjected to a reduced pressure treatment to remove residual moisture. Then, 15.2 parts of 4,4′-dicyclohexylmethane diisocyanate (25.2 parts based on the total hydroxyl groups) , 3 equivalents), and 0.01 part of dibutyltin dilaurate was further added. The mixture was reacted at 65 ° C. for 3 hours to convert the polyol component into isocyanate. A solution prepared by uniformly dissolving 200 parts of polymerized rosin having a softening point of 100 ° C. as a tackifying resin in 50 parts of butyl acrylate was added thereto, and the whole was uniformly stirred. Thereafter, 6.3 parts (equivalent to carboxyl group) of triethylamine was added to carry out a carboxyl group neutralization reaction. 850 parts of distilled water was placed in another flask, and after the atmosphere was replaced with nitrogen for 1.5 hours, the above neutralized product was dropped by a dropping funnel and dispersed. In addition, ethylenediamine 1.9
The resulting mixture was diluted three times with distilled water and added. Further, 0.02 part of 2,2-azobis [2- (2-imidazolin-2-yl)] propane was added to start a polymerization reaction, and the mixture was heated at 50 ° C for 4 hours. Then, the temperature was raised to 70 ° C. and the temperature was held for 1 hour to extend the main chain and polymerize.

In this way, an aqueous dispersion in which the polymerized rosin having a softening point of 100 ° C. as a tackifying resin is stably dispersed in water together with a urethane polymer and an acrylic polymer without using an emulsifier is obtained. Was. The aqueous dispersion of this tackifying resin contained 54.8% by weight of the tackifying resin (polymerized rosin having a softening point of 100 ° C.), 27.3% by weight of the polyol component, and 4% by weight of the solid content. .
2% by weight and 13.7% by weight of an acrylic polymer (the remaining components contained a neutralizing agent, a urethane main chain extender, and the like).

Example 4 100 parts of a viscous liquid comprising a mixture of polytetramethylene glycol obtained in Example 3 and acrylic polyol were added to
Add 140 parts of polymerized rosin having a softening point of 100 ° C,
To make a uniform liquid. This was heated to 100 ° C. and subjected to a reduced pressure treatment to remove residual moisture. In addition, 4,
4'-dicyclohexylmethane diisocyanate
2 parts (2.3 equivalents based on all hydroxyl groups) were added, and further 0.01 part of dibutyltin dilaurate was added. The mixture was reacted at 65 ° C. for 3 hours to convert the polyol component into isocyanate. I went. Thereafter, 6.3 parts of triethylamine (equivalent to the carboxyl group) was added and stirred to carry out a neutralization reaction of the carboxyl group. Add 350 liters of distilled water
Parts were added and dispersed. Further, 1.9 parts of ethylenediamine was diluted three times with distilled water and added, and the main chain was extended by the reaction of the remaining isocyanate group.

In this way, an aqueous dispersion in which polymerized rosin having a softening point of 100 ° C. as a tackifying resin was stably dispersed in water together with a urethane polymer without using an emulsifier was obtained. The aqueous dispersion of the tackifier resin contained 53.5% by weight of a tackifier resin (polymerized rosin having a softening point of 100 ° C.), 38.2% by weight of a polyol component, and 5% by weight of a polyisocyanate component. 0.8% by weight (the remaining components include a neutralizing agent and a main chain extender of urethane).

Reference Example 1 Polypropylene glycol (number average molecular weight 3,000,
In the presence of 50 parts of a hydroxyl group (0.00067 equivalents / g), 45 parts of butyl acrylate and 5 parts of acrylic acid were combined with 1 part of 2-mercaptoethanol as a chain transfer agent having a hydroxyl group and 2,2 parts as a polymerization initiator. Polymerization reaction was carried out at 50 ° C. for 6 hours in a nitrogen stream using 0.05 parts of -azobisisobutyronitrile to obtain a viscous liquid. This viscous liquid is
A peak composed of a mixture of polypropylene glycol and acrylic polyol, having a number average molecular weight of 3,000 derived from polypropylene glycol and a number average molecular weight derived from acrylic polyol of 7, as measured by GPC. , 5
A peak of 00 was observed, indicating that the acrylic polyol had a carboxyl group content of 0.0014 equivalent / g and a hydroxyl group content of 0.00025 equivalent / g.

This viscous liquid was heated to 100 ° C. and subjected to a reduced pressure treatment to remove residual moisture. To this were added 11.8 parts of isophorone diisocyanate (2.3 parts based on all hydroxyl groups).
Double equivalent), and dibutyltin dilaurate (0.1 equivalent) was added.
After adding 01 parts, the mixture was reacted at 65 ° C. for 3 hours to convert the hydroxyl group into isocyanate. Furthermore, triethylamine is added to 7
(Equivalent to carboxyl group) to neutralize the carboxyl group. To this, 150 parts of water was added with stirring to carry out a dispersion treatment. Thereafter, ethylenediamine 1.
8 parts (equivalent to the remaining isocyanate group) diluted with 16.2 parts of water are added and reacted at 65 ° C. for 3 hours to obtain a urethane polymer having a neutralized carboxyl group in the molecular skeleton. -Was obtained as an aqueous dispersion.

This aqueous dispersion (solid content: 42.2% by weight) 1
Further, 68 parts of water was added to 00 parts, and after stirring uniformly, a monomer mixture consisting of 41.9 parts of butyl acrylate and 0.1 part of trimethylolpropane triacrylate was added. After stirring for a period of time to absorb the monomer mixture into urethane polymer particles, the temperature was raised to 50 ° C., and 2,2-azobis [2- (2-imidazolin-2-yl)] propane 0.02 Parts were added to initiate the polymerization reaction. After maintaining at 50 ° C. for 4 hours, the temperature was increased to 70 ° C. and maintained for 1 hour, and then cooled.

Thus, an aqueous dispersion containing a urethane polymer and an acrylic polymer as main components as pressure-sensitive adhesive polymers was obtained, and this was used as a water-dispersible pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition was excellent in water resistance because no emulsifier was used.
Next, the water-dispersed pressure-sensitive adhesive composition was applied to a thickness of 2
It was applied on a 5 μm polyester film so that the thickness after drying was 40 μm, and dried at 120 ° C. for 3 minutes to produce a pressure-sensitive adhesive tape.

Examples 5 to 8 An aqueous dispersion containing a urethane polymer and an acrylic polymer as pressure-sensitive adhesive polymers obtained in Reference Example 1 as main components was added to 100 parts of the solid content of Examples 1 to 8. The aqueous dispersion of the tackifier resin obtained in 4 was added to 20 parts of the tackifier resin and uniformly mixed to prepare four types of water-dispersible pressure-sensitive adhesive compositions. Next, except that this water-dispersed pressure-sensitive adhesive composition was used, Reference Example 1 was used.
In the same manner as described above, four types of pressure-sensitive adhesive tapes were produced.

Each of the pressure-sensitive adhesive tapes prepared in Reference Example 1 and Examples 5 to 8 was subjected to the following method.
The adhesive strength and the holding power (cohesive strength) were examined. In addition, as a water resistance test, the pressure-sensitive adhesive tape was immersed in water,
The whitening property after 4 hours was examined. These results were as shown in Table 1.

<Adhesive Strength> A pressure-sensitive adhesive tape having a size of 20 mm × 100 mm was used as an adherend with a sandpaper of 280 yen.
A 2 kg roller is pressure-bonded to the stainless steel plate sanded with a pad by a method of reciprocating one time.
The force required for peeling (180 degree peeling) was measured.

<Holding force (cohesive force)> A pressure-sensitive adhesive tape was adhered to a phenolic resin plate with an adhesion area of 10 mm × 20 mm, and after 20 minutes, left at 80 ° C. for 20 minutes. -Hang the resin plate on the free end of the adhesive tape.
A uniform load of 0 g was applied, and the time (minute) until the adhesive tape dropped at 80 ° C. was measured.

[0049]

As is evident from the results in Table 1 above, the pressure-sensitive adhesive tapes of Examples 5 to 8 were prepared by adding the urethane polymer and the acrylic polymer obtained in Reference Example 1 as the main components without emulsifier. By mixing the aqueous dispersions of the tackifying resins of Examples 1 to 4 into the aqueous dispersion of the type to form the water-dispersed pressure-sensitive adhesive composition, Thus, the adhesive force can be increased while maintaining the good holding force based on Reference Example 1 as it is, or without observing a large decrease in the holding force, and the excellent water resistance of Reference Example 1 can be maintained as it is. You can see that there is.

In Examples 5 to 8 described above, the aqueous dispersion containing urethane polymer and acrylic polymer as pressure-sensitive adhesive polymers as main components was used.
The aqueous dispersion of the tackifying resin obtained in each of Nos. 1 to 4 was blended so that the amount of the tackifying resin was 20 parts per 100 parts of the pressure-sensitive adhesive polymer. It can be appropriately changed according to the type of the polymer, the type of the tackifier resin, and the desired adhesive properties such as adhesive strength and holding power. Generally, for 100 parts of pressure sensitive adhesive polymer,
It is preferable that the ratio of the tackifier resin is 10 to 50 parts.

[0052]

As described above, according to the present invention, when a polyol component and a polyisocyanate component are reacted to form a urethane polymer stably dispersed in water, such a urethane reaction system is used. When an acrylic monomer is further added to the mixture and the acrylic monomer is polymerized to form an acrylic polymer together with the urethane polymer, a tackifier resin is mixed with the polyol component, or the acrylic monomer is adhered to the acrylic monomer. By dissolving the imparting resin, the tackifying resin can be used together with a urethane polymer or an acrylic polymer without using an emulsifier,
An aqueous dispersion stably dispersed in water can be obtained. By mixing this with an aqueous dispersion containing a pressure-sensitive adhesive polymer as a main component, excellent adhesive properties and excellent water resistance can be obtained. An excellent water-dispersed pressure-sensitive adhesive composition can be obtained.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuko Yamamoto 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Yoshinori Yoshida 1-1-2 Shimohozumi, Ibaraki-shi, Osaka F-term in Nitto Denko Corporation (reference) 4J002 AE051 AF011 BA011 BC021 BG043 BG053 BK001 CK022 CK032 CK042 CK052 DE026 FD206 GJ01 HA07 4J034 BA03 BA07 BA08 DA01 DB04 DB08 DC50 DF01 DG14 D01 DG14 DG24 D01 HC22 HC52 HC71 JA01 JA24 JA25 JA30 LA16 MA21 MA22 MA26 MA29 QC05 RA08 4J040 DF042 DL151 EF081 EF111 EF131 JA03 JB09 KA26 LA07 QA01

Claims (5)

[Claims] 1. A tackifier resin is dispersed in water together with a urethane polymer comprising a polyol component and a polyisocyanate component or an acrylic polymer, and the tackifier resin is 40 to 40% of the solid content. 90% by weight, 5-50% by weight of a polyol component, 1-20% by weight of a polyisocyanate component, 0-20% by weight of an acrylic polymer
An aqueous dispersion of a tackifier resin, characterized in that: 2. The aqueous dispersion of a tackifier resin according to claim 1, wherein the polyol component comprises a polyether polyol, a polyester polyol, an acrylic polyol, or a mixture thereof. 3. A tackifier resin is mixed with a polyol component, a polyisocyanate component is reacted with the tackifier resin, and the carboxyl group contained in the polyol component is neutralized and dispersed in water to remain. A method for producing an aqueous dispersion of a tackifier resin, wherein the main chain is extended by the reaction of an isocyanate group to obtain an aqueous dispersion in which the tackifier resin is dispersed in water together with a urethane polymer. 4. A polyisocyanate component is reacted with a polyol component, a tackifier resin dissolved in an acrylic monomer is added thereto, and a carboxyl group contained in the polyol component is neutralized to obtain water. Main chain elongation by the reaction of the remaining isocyanate groups and acrylic monomer
A method of producing an aqueous dispersion of a tackifier resin, wherein the aqueous dispersion of the tackifier resin is dispersed in water together with a urethane polymer and an acrylic polymer. 5. A water-dispersed type pressure-sensitive composition comprising a water-based dispersion containing the tackifier resin according to claim 1 and an aqueous dispersion containing a pressure-sensitive adhesive polymer as a main component. Adhesive composition.