JP2001200228A - Water dispersible, non-crosslinking pressure-sensitive adhesive composition; and adhesive sheet therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water dispersible, non-crosslinking pressure-sensitive adhesive composition which is a water dispersible type having no problems on an environmental hygiene and a safety sanitation and which can easily adjust the balance between the adhesive characteristics as a non-crosslinking type that manages to get over a drawback accompanying a crosslinking treatment. SOLUTION: The water dispersible, non-crosslinking pressure-sensitive adhesive composition comprises a blend of a urethane-acrylic hybrid polymer water dispersion consisting of 10-90 wt.% of a urethane component and 90-10 wt.% of an acrylic component and having neutralized carboxyl groups in the molecule, and a tackifying resin water dispersion in the blend ratio of 5-100 pts.wt. of the tackifying resin relative to 100 pts.wt. of the above urethane-acrylic hybrid polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-dispersed non-crosslinked pressure-sensitive adhesive composition and an adhesive sheet (sheet, tape, etc.) obtained by providing this dried coating film on a support. ).

[0002]

2. Description of the Related Art In recent years, from the viewpoints of environmental hygiene and safety and hygiene, a method of producing an adhesive sheet using a pressure-sensitive adhesive has been switched to a method using no organic solvent.
Hot melt type and emulsion type are known, but hot melt type has a problem in heat resistance.
Can only be used for limited applications.

In the emulsion type, a crosslinking treatment is generally carried out using a crosslinking agent in order to raise the heat resistance and the holding ability to a practical level.
The aging process was not completed in the manufacturing process of the products, and it was necessary to perform an aging treatment after the manufacturing. Without this treatment, the crosslinking progressed with time during use, and the characteristics were liable to change. Further, when a tackifier resin is mixed to improve properties such as adhesive strength, remarkable decrease in heat resistance occurs, and it is difficult to balance the adhesive properties.

[0004]

As described above, the emulsion type is excellent in heat resistance and the like as compared with the hot melt type, but the drawbacks associated with the crosslinking treatment for further raising these characteristics to a practical level. Further, there is a problem that it is difficult to balance the adhesive properties due to a decrease in heat resistance due to the mixing of the tackifier resin.

[0005] In view of such circumstances, the present invention is a water-dispersed type which has no problem in environmental hygiene and safety and health, and which is a non-crosslinked type which can avoid all the difficulties involved in the crosslinking treatment. Aqueous dispersion that can exhibit adhesiveness and holding properties, can improve the adhesive strength without lowering the above heat resistance and holding properties by mixing the tackifier resin, and can easily balance the adhesive properties. It is an object of the present invention to provide a non-crosslinked pressure-sensitive adhesive composition and an adhesive sheet thereof.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that a urethane-acryl having a neutralized carboxyl group in the molecule consisting of a urethane component and an acrylic component. When a water dispersion of a hybrid polymer is used as a base, a water-dispersion type pressure-sensitive adhesive composition having no environmental health or safety / hygiene problems can be used without performing a crosslinking treatment. Retention can be exhibited, and by mixing the aqueous dispersion of the tackifier resin with the above aqueous dispersion, it is possible to improve the adhesive strength without lowering the heat resistance and the retention. Thereby, the water-dispersed non-crosslinked pressure-sensitive adhesive composition can easily balance the adhesive properties without causing the difficulties associated with the conventional crosslinking treatment, that is, the aging treatment and the aging of the properties. I know that obtained, but was Itaritsu completed the present invention.

That is, the present invention provides a urethane component
Urethane having 90% by weight and 90 to 10% by weight of an acrylic component and having a neutralized carboxyl group in the molecule.
The aqueous dispersion of the tackifier resin is added to the aqueous dispersion of the acrylic hybrid polymer, and the urethane-acryl hybrid polymer 10 is used.
The present invention relates to a water-dispersed non-crosslinked pressure-sensitive adhesive composition obtained by mixing a tackifier resin in a ratio of 5 to 100 parts by weight per 0 parts by weight. The present invention also relates to an adhesive sheet comprising a support and an adhesive layer comprising a dried coating film of the above-mentioned water-dispersed non-crosslinked pressure-sensitive adhesive composition.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The urethane-acrylic hybrid polymer aqueous dispersion according to the present invention contains 10 to 90% by weight, preferably 20% by weight, of a urethane component composed of polyurethane obtained by reacting a polyol and a polyisocyanate. ~ 80
Urethane-acryl hybrid polymer having 90 to 10% by weight, preferably 80 to 20% by weight of an acrylic component obtained by polymerizing an acrylic monomer, and having a neutralized carboxyl group in the molecule. -Is an aqueous dispersion uniformly and stably dispersed in water. here,
When the urethane component is less than 10% by weight and the acrylic component exceeds 90% by weight, heat resistance and retention are reduced, and the urethane component exceeds 90% by weight.
When the acrylic component is less than 10% by weight, the adhesive strength and the tackiness (tack) are reduced, so that it is difficult to balance the adhesive properties.

Such an aqueous dispersion of a urethane-acrylic hybrid polymer can be prepared by various methods.
As a method that does not require the use of an emulsifier, a urethane prepolymer is produced from polyol and polyisocyanate, and an acrylic monomer is added thereto.
A method of neutralizing the carboxyl group contained in the above and dispersing it in water to extend the main chain of the prepolymer and polymerize the acrylic monomer, to produce a urethane prepolymer in the same manner as described above and to include it in this A method in which carboxyl groups are neutralized and dispersed in water, the main chain of the prepolymer is extended, and then an acrylic monomer is added to carry out polymerization. Acrylic polio made from acrylic monomer
By substituting with an alkyl group, a urethane prepolymer in which an acrylic component has been introduced in advance is produced, a carboxyl group contained therein is neutralized and dispersed in water, and the main chain of the prepolymer is extended, whereby It can be easily prepared.

[0010] The above-mentioned methods (1) to (3) can be prepared by appropriately combining them. For example, in the above method, after extending the main chain of the prepolymer and polymerizing the acrylic monomer, and then adding the acrylic monomer again and polymerizing, or in the above method, the main chain of the prepolymer was extended. That is, a method of adding an acrylic monomer and polymerizing may be employed. In these various methods, the urethane component and the acrylic component are adjusted by adjusting the amount of the polyol and polyisocyanate used as the raw material of the urethane component and the amount of the acrylic monomer used as the material of the acrylic component. Is set so as to fall within the above range.

In the above method, the polyol as a raw material of the urethane component may be a low molecular weight polyol having at least two or more hydroxyl groups in one molecule.
Or high molecular weight polyol. Low molecular weight polyols include divalent alcohols such as ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, and hexamethylene glycol, and trimethylol.
There are trivalent alcohols such as lupropane, glycerin and pentaerythritol. The high molecular weight polyols include polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, the above-mentioned divalent alcohol, and dipropylene glycol.
1,4-butanediol, 1,6-hexanediol
Lactone ring-opening polymer polyols, such as polyester polyols and polycaprolactone, which are polycondensates of alcohols such as thiol and neopentyl glycol with dibasic acids such as adipic acid, azelaic acid and sebacic acid Le, Polycar
Epoxy polyols such as bonediol and amine-modified epoxy resin.

As the polyisocyanate which is another raw material of the urethane component, aromatic, aliphatic and alicyclic polyisocyanates are used. Among them, isophorone diisocyanate, cyclohexane-1,4-diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate are preferred from the viewpoint of prompt reaction with polyol and suppression of reaction with water. Preferred are alicyclic polyisocyanates such as. The polyisocyanate is not limited to the above-mentioned diisocyanate, but may be a tri- or more isocyanate. The amount of the polyisocyanate to be used is such that NCO / OH (equivalent ratio) is 1.1 to 3.1.
It is preferable that the ratio be 0. If the amount is too small, the cohesiveness of the urethane becomes low or the hydroxyl groups become excessive, so that the chain cannot be extended after dispersion in water, and it is difficult to increase the molecular weight. On the other hand, if the amount is too large, the physical properties of the urethane are not flexible, and the adhesive properties are likely to be lowered.

In producing a urethane prepolymer by reacting a polyol with a polyisocyanate, a carboxyl group is contained in the molecule of the prepolymer so that water can be dispersed by neutralization. As a part of the polyol, a carboxyl group-containing polyol is used. Specifically, 2,2-dimethylolpropionic acid,
There are 2,2-dimethylolacetic acid and 2,2-dimethylolbutyric acid, and 2,2-dimethylolpropionic acid is particularly preferred. These use a small amount of a solvent such as N-methylpyrrolidone to promptly advance the reaction,
It is better to dissolve in this and add. In the above reaction, in order to suppress the reaction between polyisocyanate and water, it is preferable to replace the raw material with dry air or nitrogen, or to dehydrate each raw material. As a reaction catalyst, dibutyltin dilaurate, tin octoate, 1,4-diazabicyclo (2,2,2) octane, or the like may be used.

In the above method, an acrylic monomer is first added to the urethane prepolymer thus formed, and then the carboxyl groups contained in the prepolymer are neutralized and dispersed in water. The main chain extension of the prepolymer and the polymerization of the acrylic monomer are carried out simultaneously or continuously. In the above method, the urethane prepolymer produced as described above is first neutralized by dispersing the carboxyl group contained therein in water, and after extending the main chain of the prepolymer, Acrylic monomer is added to this and polymerization is performed.

The acrylic monomers used as raw materials for the acrylic component include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, (Meta)
Alkyl (meth) acrylates such as hexyl acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate Used. In addition, hydroxyl-containing (meth) acrylates such as (meth) acrylic acid, hydroxyethyl (meth) acrylate, and hydroxylpropyl (meth) acrylate, (meth) acrylamide, N-
Methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide and the like can also be used. Further, other monomers such as styrene, vinyl acetate, maleic acid, and itaconic acid may be used in combination, and those obtained by copolymerizing these other monomers are also included in the acrylic component according to the present invention.

In order to neutralize the carboxyl groups contained in the urethane prepolymer, sodium hydroxide,
Potassium hydroxide, triethylamine and the like are used.
After this neutralization, in order to disperse in water, the neutralized substance may be added to water, or water may be added to the neutralized substance. At this time, it is preferable to disperse while stirring, and in addition to stirring with a normal stirrer, stirring may be performed using a homomixer or a homogenizer. In extending the main chain of the urethane prepolymer, it is preferable to add a diamine. It is preferable that the amount of the diamine to be added is 1 equivalent to the remaining NCO equivalent. As the diamine, ethylene diamine, propylene diamine, hexamethylene diamine, or the like is used.

The polymerization of the acrylic monomer can be carried out by adding a polymerization initiator and heating to a predetermined temperature. As the polymerization initiator, azobisisobutyronitrile, azobisisobutylvaleronitrile, 2,2
2'-azobis [2- (2-imidazolin-2-yl)
An azo compound such as [propane] or an organic peroxide such as benzoyl peroxide is used. The polymerization initiator may be oil-soluble or water-soluble, and a powdery initiator is used by dissolving it in water or a small amount of an organic solvent. The amount of the polymerization initiator to be used is generally 0.01 to 5 parts by weight, preferably 0.05 to 2 parts by weight, based on 100 parts by weight of the acrylic monomer.

In the above method, when a polyol and a polyisocyanate are reacted in the same manner as described above to produce a urethane prepolymer, a part of the polyol is converted to an acrylic polyol using an acrylic monomer as a raw material. -A urethane prepolymer in which acrylic components have been introduced in advance by replacing
Is produced, and the carboxyl group contained therein is neutralized and dispersed in water to extend the main chain of the prepolymer.
It can be performed in the same manner as described above.

The acrylic polyol is an acrylic monomer.
As a main component, the above-mentioned alkyl (meth) acrylate was used as a main component, and the above-mentioned hydroxyl group-containing (meth) acrylate and further a carboxyl group-containing monomer such as (meth) acrylic acid, maleic acid, and itaconic acid were added thereto. The monomer mixture was prepared in the presence of a hydroxyl group-containing chain transfer agent such as 2-mercaptoethanol, 1-mercapto-2-propanol, 3-mercapto-1-propanol, and p-mercaptophenol. Those obtained by copolymerization using an azo initiator such as 2,2'-azobisisobutyronitrile or a peroxide initiator such as benzoyl peroxide are particularly preferably used. Further, such an acrylic polyol is more preferably one obtained by performing the above copolymerization in the presence of a high molecular weight polyol or the like. This is because good results can be obtained on the compatibility between the high molecular polyol and the like and the acrylic polyol.

The thus obtained acrylic polio
Has a hydroxyl group derived from a hydroxyl group-containing (meth) acrylate and a hydroxyl group-containing chain transfer agent in the molecule, the hydroxyl group being involved in the reaction with the polyisocyanate, and a carboxyl group-containing monomer in the molecule. And the carboxyl group is introduced into the molecule of the urethane prepolymer produced by the above reaction. Therefore, in the above-mentioned method using an acrylic polyol, a carboxyl group-containing polyol such as the aforementioned 2,2-dimethylolpropionic acid is used as a part of the polyol when reacting with the polyisocyanate. There is no particular need to use.

In the present invention, the aqueous dispersion of a urethane-acryl hybrid polymer having a carboxyl group neutralized in the molecule comprising the urethane component and the acrylic component prepared in this manner is further added with a tackifier resin. The aqueous dispersion is mixed to obtain a water-dispersed non-crosslinked pressure-sensitive adhesive composition. The aqueous dispersion of the tackifying resin is one or more selected from rosin resin, terpene resin, aliphatic petroleum resin, alicyclic petroleum resin, aromatic petroleum resin, xylene resin and the like. Is uniformly dispersed in water. The softening point of the tackifier resin is usually 20 to
The temperature is 180 ° C., preferably 95 ° C. or higher, and is conveniently selected according to the required adhesive properties.

The aqueous dispersion of the tackifier resin is such that the aqueous dispersion of the urethane-acryl hybrid polymer has a tackifier resin as a solid content of 5 to 5 per 100 parts of the solid urethane-acryl hybrid polymer. By mixing at a ratio of 100 parts by weight, preferably 10 to 60 parts by weight, it is possible to achieve a good balance between the adhesive strength, the heat resistance, the retention and the like. On the other hand, if the amount of the tackifying resin is less than 5 parts by weight, the adhesive strength becomes insufficient, and if it exceeds 100 parts by weight, the heat resistance and the retention are deteriorated, and in all cases, it is difficult to balance the adhesive properties.

As described above, the water-dispersed non-crosslinked pressure-sensitive adhesive composition of the present invention can be used as it is without adding a crosslinking agent thereto. Other dispersibility improvers, thickeners and the like may be blended and used. Furthermore, various additives used in general pressure-sensitive adhesive compositions, such as a softener and a pigment, can be blended and used in usual amounts.

The adhesive sheets of the present invention are prepared by providing an adhesive layer comprising a dried coating film of the above-mentioned water-dispersed non-crosslinked pressure-sensitive adhesive composition on a support, and forming a sheet or tape. It is in the shape of a loop. As the support, a non-peelable support such as a plastic film, a nonwoven fabric, paper, or a metal foil, or a peelable support such as a release paper is used. The dried coating film is provided by applying the above-mentioned pressure-sensitive adhesive composition on a support and drying the coating film. The dried coating film provided on the peelable support is transferred to a non-peelable support. May be.

[0025]

EXAMPLES Examples of the present invention will be described below in more detail. However, the present invention is not limited only to the following examples. In the following, “parts” means “parts by weight”.

Example 1 Diethylene glycol adipate (number-average molecular weight: 2,500, hydroxyl value: 43.000) was placed in a flask equipped with a reflux cooling pipe, a gas introduction pipe (also serving as a degassing pipe), a stirrer, and a thermometer.
6) 100 parts were added, and the mixture was heated and deaerated at 100 ° C. to remove water. The pressure was returned to normal pressure, and 30.4 parts of 4,4'-dicyclohexylmethane diisocyanate, 0.45 part of hydroxyethyl acrylate and 7.8 parts of dimethylolpropionic acid were dried, and dried with N-methyl. Pyrrolidone 19.5
Dissolved in the solution and added. To this, 0.07 parts of dibutyltin dilaurate was added and reacted at 65 ° C. for 4 hours to obtain a urethane prepolymer having a carboxyl group in the molecule.

The urethane prepolymer was cooled to 30 ° C., and 150.48 parts of butyl acrylate was added thereto.
After stirring well, 11.77 parts of triethylamine was added, and the mixture was stirred well and neutralized. Distilled water 4 in another flask
51.34 parts were added, and the above neutralized product was dropped by a dropping funnel. After completion of the dropwise addition, ethylenediamine 1.0
4 parts were diluted with 9.36 parts of distilled water, and the mixture was stirred for 1 hour. After purging with nitrogen for 1 hour, 2,2'-azobis [2- (2
-Imidazolin-2-yl) propane] was dissolved in 1 part of methanol and diluted with 1 part of distilled water. This was heated to 60 ° C. and reacted for 5 hours.
The mixture was heated to 0 ° C. and reacted for 2 hours.

By performing main chain extension and polymerization as described above,
An aqueous dispersion of a urethane-acryl hybrid polymer having a carboxyl group neutralized in the molecule and comprising 50% by weight of a urethane component and 50% by weight of an acrylic component was obtained. An aqueous dispersion of a terpene phenol-based tackifying resin (“Tamanol E100” manufactured by Arakawa Chemical Co., Ltd.,
(50 ° C.) 45.1 parts were mixed to prepare a water-dispersed non-crosslinked pressure-sensitive adhesive composition. The above tackifying resin (solid content) was in a proportion of 15 parts with respect to 100 parts of the urethane-acryl hybrid polymer (solid content).

Next, a non-peelable support having a thickness of 38
Using a polyethylene terephthalate film of μm,
The water-dispersed non-crosslinked pressure-sensitive adhesive composition is coated on the non-peelable support with an applicator, and dried in a dryer at 120 ° C.
For 5 minutes to form an adhesive layer composed of a dried coating film having a thickness of 50 μm, thereby preparing an adhesive sheet for measuring adhesive force and holding force. Also, using a silicone-treated polyethylene terephthalate film as a peelable support,
On this peelable support, the thickness is 50 μm in the same manner as described above.
An adhesive layer for measuring rebound resistance was prepared by forming an adhesive layer comprising a dried coating film of the above.

Example 2 In the same flask as in Example 1, polypropylene glyco-
(Number average molecular weight 3,000, hydroxyl value 35.5) 10
0 parts were added, and the mixture was heated and degassed at 100 ° C. to remove water. The pressure was returned to normal pressure, and 32.98 parts of 4,4'-dicyclohexylmethane diisocyanate, 0.365 parts of hydroxyethyl acrylate and 9.6 parts of dimethylolpropionic acid were dried. It was dissolved and added to 24 parts of pyrrolidone. To this dibutyltin dilaurate 0.07
Then, the mixture was reacted at 65 ° C. for 4 hours to obtain a urethane prepolymer having a carboxyl group in the molecule.

The urethane prepolymer was cooled to 30 ° C., 157.5 parts of butyl acrylate was added thereto, and the mixture was stirred well, and then 14.48 parts of triethylamine was added, and the mixture was stirred well. To this, 472.39 parts of distilled water was dropped by a dropping funnel. Stir well during the addition. After completion of the dropping, 1.27 parts of ethylenediamine was added to 11.4 parts of distilled water.
The mixture was diluted with 3 parts, and the mixture was stirred for 1 hour. After purging with nitrogen for 1 hour, 2,2'-azobis [2- (2-imidazoline-2)
-Yl) propane] was dissolved in 1 part of methanol and diluted with 1 part of distilled water. This was heated to 60 ° C. and reacted for 5 hours, and further heated to 70 ° C. and reacted for 2 hours.

314.78 parts of butyl acrylate was further added to the aqueous dispersion obtained by subjecting the main chain to extension and polymerization as described above, stirred well, and replaced with nitrogen for 1 hour.
0.13 parts of azobis [2- (2-imidazolin-2-yl) propane] was added. This was heated to 60 ° C. and reacted for 5 hours, and further heated to 70 ° C. and reacted for 2 hours.
By conducting polymerization in this manner, a urethane-acryl hybrid polymer having a carboxyl group neutralized in the molecule consisting of 25% by weight of a urethane component and 75% by weight of an acrylic component.
Was obtained.

An aqueous dispersion of the polymerized rosin ester (“Tamanol E625” manufactured by Arakawa Chemical Co., softening point 125 ° C.) was added to the aqueous dispersion of the urethane-acrylic hybrid polymer.
5.94 parts were mixed to prepare a water-dispersed non-crosslinked pressure-sensitive adhesive composition. The above tackifying resin (solid content) is the urethane-acryl hybrid polymer (solid content) 100
The ratio was 20 parts per part. Next, except for using this water-dispersed non-crosslinked pressure-sensitive adhesive composition,
In the same manner as in Example 1, an adhesive sheet for measuring the adhesive force and the holding force and an adhesive sheet for measuring the rebound resistance were produced.

Example 3 Polypropylene glycol (number average molecular weight 3,000,
In the presence of 50 parts of a hydroxyl value of 37.1), a monomer mixture consisting of 45 parts of butyl acrylate and 5 parts of acrylic acid was mixed with 1 part of 2-mercaptoethanol as a hydroxyl-containing chain transfer agent and 2,2 parts as a polymerization initiator. Using 0.1 part of 2'-azobisisobutyronitrile, a polymerization reaction was carried out at 50 ° C for 6 hours under a nitrogen stream to obtain a viscous liquid. The viscous liquid consisted of a mixture of the above-mentioned polypropylene glycol and the formed acrylic polyol having a carboxyl group in the molecule.

Next, this viscous liquid was heated to 100 ° C. and subjected to a reduced pressure treatment to remove residual moisture. To this, 10.2 parts of isophorone diisocyanate was added, and 0.03 parts of dibutyltin dilaurate was further added. The mixture was reacted at 65 ° C. for 3 hours to obtain a urethane prepolymer containing a carboxyl group in the molecule. I got To the urethane prepolymer, 7 parts of triethylamine was added to neutralize the carboxyl group. To this neutralized product, 276.3 parts of water was added while stirring,
Dispersed in water. To this was added 1.39 parts of ethylenediamine diluted with 12.5 parts of water and reacted at 65 ° C. for 3 hours.

By extending the main chain in this way, an aqueous dispersion of a urethane-acryl hybrid polymer having a carboxyl group neutralized in the molecule and comprising 51% by weight of a urethane component and 49% by weight of an acrylic component is obtained. Was. In this aqueous dispersion,
Aqueous dispersion of terpene phenol-based tackifying resin ("TAMANOL E100" manufactured by Arakawa Chemical Co., softening point 150 ° C) 1
7.74 parts were mixed to prepare a water-dispersed non-crosslinked pressure-sensitive adhesive composition. The above tackifying resin (solid content) was in a proportion of 15 parts with respect to 100 parts of the urethane-acryl hybrid polymer (solid content). Next, in the same manner as in Example 1, except that this water-dispersed non-crosslinked pressure-sensitive adhesive composition was used, an adhesive sheet for measuring adhesive force and holding force and an adhesive sheet for measuring rebound resistance were used. A sheet was made.

Using the adhesive sheets for measuring adhesive force and holding force and the adhesive sheet for measuring rebound resistance prepared in Examples 1 to 3 above, the adhesive force and holding force were determined by the following method. And repulsion resistance were evaluated. The results were as shown in Table 1.

<Measurement of Adhesive Force> A 20 mm × 100 mm test tape was measured using an adhesive sheet for measuring adhesive force and holding force.
SUS # 304BA as an adherend
A 2 kg roller was pressure-bonded to the plate by one reciprocation. 40
After standing for 1 week in an atmosphere of 92 ° C. and 92% RH,
The force required for peeling at 180 ° peeling was measured in an atmosphere at 65 ° C. and 65% RH under a tensile speed of 300 mm / min.

<Measurement of Holding Force> Using an adhesive sheet for measuring the adhesive force and the holding force, this was applied to a phenolic resin plate by one.
Bonding was performed with a bonding area of 0 mm × 20 mm. After 20 minutes, 4
It was left at 0 ° C. for 20 minutes, then the phenol resin plate was hung down, a uniform load of 500 g was applied to the free end of the adhesive sheet, and the time until the adhesive sheet dropped at 40 ° C. was measured. .

<Measurement of Rebound Resistance> An aluminum plate (area: 10 mm × 100 mm) having a thickness of 0.5 mm was adhered to the surface of the adhesive layer using an adhesive sheet for measuring repulsion resistance. The support was peeled off and bonded to the side of a cylindrical acrylic round bar having a diameter of 50 mm. This was left in an atmosphere of 40 ° C. for 2 hours, and the height (mm) at which the edge of the aluminum plate was peeled was measured.

[0041]

As is clear from Table 1 above, each of the adhesive sheets using the water-dispersed non-crosslinked pressure-sensitive adhesive compositions of Examples 1 to 3 of the present invention was bonded under an atmosphere of 40 ° C. It satisfies the force and holding power, and also has excellent repulsion resistance, which is an indicator of the balance between the two. From this test result, it is easy to balance the adhesive strength with the adhesive properties such as heat resistance and holding ability. It turns out that it can be taken.

[0043]

As described above, the present invention provides an aqueous dispersion of a urethane-acryl hybrid polymer having a carboxyl group neutralized in a molecule consisting of a urethane component and an acrylic component. Adhesive properties as a water-dispersed type with no problems in environmental hygiene and safety and hygiene, and a non-cross-linked type without the difficulties associated with conventional cross-linking treatment A water-dispersible non-crosslinked pressure-sensitive adhesive composition and an adhesive sheet thereof can be provided which can easily balance the pressure-sensitive adhesive composition.

Continued 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 Nitto Denko stock In-house F-term (reference) 4J004 AA02 AA04 AA10 AA12 AA14 AB01 CA02 CA06 CA08 CB01 CB02 CC02 4J040 BA202 DF011 DF041 DF051 DF061 DN032 DN072 EB082 EF051 EF111 EF121 EF131 EF11 GAEF EF31 EF31 EF31 EF201 EF291 LA08 LA11

Claims (2)

[Claims] 1. An aqueous dispersion of a urethane-acryl hybrid polymer having a carboxyl group neutralized in a molecule consisting of 10 to 90% by weight of a urethane component and 90 to 10% by weight of an acrylic component is added with a tackifier resin. A water-dispersed non-crosslinked pressure-sensitive adhesive composition obtained by mixing an aqueous dispersion at a ratio of 5 to 100 parts by weight of a tackifier resin per 100 parts by weight of the urethane-acrylic hybrid polymer. 2. An adhesive sheet comprising a support and an adhesive layer comprising a dried coating film of the water-dispersed non-crosslinked pressure-sensitive adhesive composition according to claim 1.