JP2003313528A - Aqueous pressure-sensitive adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an aqueous pressure-sensitive acrylic adhesive composition which has excellent balance of tack, permanent adhesive strength and cohesive power, excellent adhesive strength, adhesiveness to a curved surface and low- temperature adhesive strength to a nonpolar polymer film and molding and excellent secondary processability such as shredding, punching, etc. <P>SOLUTION: The aqueous pressure-sensitive acrylic adhesive composition is obtained by mixing (A) an acrylic aqueous dispersion which is obtained by copolymerizing (a) 0.2-5 wt.% of a carboxy group-containing unsaturated monomer with (b) 0.2-1 wt.% of a phosphate group-containing unsaturated monomer, (c) 55-99.4 wt.% of an acrylic acid 4-18C alkyl ester and (d) 0.1-38.8 wt.% of another unsaturated monomer copolymerizable with these unsaturated monomers and has a glass transition temperature (calculated value) of -30 to -65°C with (B) ≥3 parts wt. and ≤20 parts wt. based on 100 parts wt. of the component (A) of an emulsion type tackifier which comprises an adhesive resin having 100-160°C softening point as a main component. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention has excellent tack, permanent adhesive strength, high cohesive strength, excellent curved surface adhesiveness, and excellent secondary workability such as cutting and punching. Due to the dioxin problem, it has excellent adhesive strength, adhesive strength, and curved surface adhesiveness to films or molded products of non-polar polymers such as polyolefins, which are being replaced from vinyl chloride films used for food wrap films. An aqueous pressure-sensitive adhesive composition is provided.

[0002]

2. Description of the Related Art Conventionally, pressure-sensitive adhesives have been used for tape,
It covers a wide range of areas such as labels, seals, and wallpaper, and the materials of adherends are plastic, metal, glass, ceramics, paper,
It is widely used in cloth, wood, and fresh food. However, the water-based pressure-sensitive acrylic adhesive has a problem that the adhesive strength, particularly the adhesive strength to a molded product of a non-polar polymer such as polyolefin, tends to be insufficient as compared with the solvent-type acrylic adhesive. It was

In solving such a problem, for example,
A conventional method of softening an acrylic aqueous dispersion or a method of decreasing the molecular weight to improve the adhesive strength, a method of blending a plasticizer, etc., and a water-dispersible acrylic pressure-sensitive adhesive having a high Tg and a low Tg. Attempts have been made, such as a method of blending with a water-dispersed acrylic adhesive having
Both methods have the drawback that a pressure-sensitive adhesive having a good balance of high adhesive strength and high cohesive strength cannot be obtained. As a result, in affixing various labels and the like, adhesiveness and curved surface adhesiveness to a film or a molded product of a non-polar polymer such as polyolefin is insufficient, and secondary workability such as cutting and punching, for example, Problems such as adhesion of adhesive resin to the cutting blade became clear.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and has a good balance between tack, permanent adhesive strength and cohesive strength, and it is possible to solve problems such as polyolefin. A water-based pressure-sensitive acrylic pressure-sensitive adhesive composition having excellent adhesion to nonpolar polymer films and molded products, especially curved surface adhesion and low-temperature adhesion, and also excellent secondary processability such as cutting and punching. It is intended to be provided.

[0005]

As a result of various studies to solve the above problems, the inventors of the present invention were able to achieve the above object by adopting the following constitution. That is, the present invention provides (A) (a) 0.2 to 5% by weight of a carboxyl group-containing unsaturated monomer, (b) 0.2 to 1% by weight of a phosphate group-containing unsaturated monomer, (c) ) Acrylic acid alkyl ester 55 to 99.4 in the range of 4 to 18 carbon atoms
% By weight, (d) an acrylic aqueous solution comprising an acrylic copolymer obtained by copolymerizing 0.1 to 38.8% by weight of another unsaturated monomer copolymerizable with these unsaturated monomers. An acrylic aqueous dispersion, wherein the acrylic copolymer has a glass transition temperature (calculated value) of −30 ° C. to −65 ° C., and (B) the acrylic aqueous dispersion. To 100 parts by weight as a solid content,
A water-based pressure-sensitive adhesive composition, characterized in that an emulsion-type tackifier mainly composed of an adhesive resin having a softening point of 160 ° C. is blended in an amount of 3 parts by weight or more and 20 parts by weight or less as a solid content. The purpose is.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The monomer used for preparing the acrylic copolymer used in the present invention is not particularly limited, but (a) the carboxyl group-containing unsaturated monomer is
Examples thereof include acrylic acid, methacrylic acid, maleic acid, itaconic acid, and the like, as well as monoalkyl esters of unsaturated polycarboxylic acids such as monomethyl itaconate and monobutyl maleate. At least one kind selected from these groups can be used. The content of the unsaturated monomer containing a carboxyl group is 0.2 to 5% by weight, preferably 0.5 to 3% by weight in the monomer mixture for producing the acrylic copolymer according to claim 1. . If it is less than 0.2% by weight, the adhesive strength tends to decrease, and if it exceeds 5% by weight, the water resistance of the pressure-sensitive adhesive tends to decrease.

Examples of the (b) phosphoric acid group-containing unsaturated monomer include mono (2-methacryloyloxyethyl) acid phosphate, polyoxypropylene allyl ether phosphate and the like. The content of the phosphoric acid group-containing unsaturated monomer is 0.3 to 1.0% by weight, more preferably 0% by weight in the monomer mixture for producing the acrylic copolymer according to (1). 0.5 to 0.8% by weight. If it is less than 0.3% by weight, the effect of sufficient adhesive force to the polyolefin film cannot be obtained, and if it exceeds 1.0% by weight, the water resistance of the pressure-sensitive adhesive tends to decrease. The alkyl ester of acrylic acid of the monomer (c) having 4 to 18 carbon atoms includes, for example, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, octyl acrylate, 2-Ethylhexyl acrylate, nonyl acrylate, isononyl acrylate, etc. are essential components for controlling the Tg of the copolymer to -30 ° C. or less, and even a single component is 2 You may combine 2 or more types.

The content of the alkyl ester of acrylic acid or methacrylic acid having 4 to 18 carbon atoms in the monomer mixture is 55 to 99.4% by weight, more preferably 60 to 95% by weight, and further preferably 65-90% by weight
Is.

The other unsaturated monomer (d) copolymerizable with the above unsaturated monomer is an aromatic unsaturated monomer having no functional group such as styrene; methyl acrylate. Acrylic acid or methacrylic acid alkyl ester such as methyl methacrylate having 1 to 3 carbon atoms, carboxylic acid vinyl ester such as vinyl acetate; 2-hydroxyethyl acrylate, hydroxypropyl acrylate, 3-hydroxybutyl (meth) Acrylate, hydroxypropyl methacrylate, glycerin mono (meth) acrylate, glycerin di (meth) acrylate
Unsaturated monomers having an alcohol hydroxyl group such as trimethyl and trimethyl ethane mono (meth) acrylate trimethyl propane mono (meth) acrylate; acrylamide, N-methyl (meth) acrylamide, N, N
Amido group-containing unsaturated monomer such as dimethylolmeth) acrylamide; Nitrile group-containing unsaturated monomer such as (meth) acrylonitrile, 2-cyanoethyl (meth) acrylate; 2-Dimethylaminoethyl (meth) acryle -To, 2-diethylaminoethyl (meth) acryle-
, 2-dimethylaminopropyl (meth) acrylate and other aminoalkyl group-containing unsaturated monomers; acrolein, diacetone acrylamide, diacetone (meth) acrylate and other carbonyl group-containing unsaturated monomers; γ Examples thereof include alkoxysilyl group-containing monomers such as methacryloxypropyltrimethoxysilane. The content of the unsaturated monomer is 0.1 to 38.8% by weight, more preferably 5 to 30% by weight, still more preferably 8 to 20% by weight.

The acrylic copolymer in the acrylic aqueous dispersion (A) used in the composition of the present invention has the above-mentioned (a) to (a).
(D) is copolymerized, and its glass transition temperature (calculated value) is −30 ° C. to −65 ° C., more preferably −40 ° C. to −60 ° C.

When the Tg is higher than -30 ° C., the tack of the pressure-sensitive adhesive layer to be obtained tends to be insufficient, and sufficient curved surface adhesive force cannot be obtained. If the Tg is lower than −65 ° C., sufficient secondary workability such as cutting and punching cannot be obtained.

The glass transition temperature (Tg) of the copolymer is F
It can be calculated by the equation of ox: 1 / Tg = ΣWi / Tgi In the above formula, Wi is the weight fraction of each component present in the copolymer, and Tgi is a glass of a homocopolymer of each component. It is a transition temperature (K).

The glass transition temperature of the homocopolymer can be obtained in numerous documents including the Japan Emulsion Industry Standard "Method for displaying film hardness of synthetic resin emulsion" JEI-107 (1996).

The gel fraction of the acrylic copolymer of the present invention refers to 100 ° C. so that the film of the pressure-sensitive adhesive composition obtained by coating the acrylic aqueous dispersion has a thickness of 20 to 30 m. After drying for 2 minutes, 1-2 g of the obtained dry film is precisely weighed (W1), put in a 200 ml beaker, and further 100 ml of THF (tetrahydrofuran).
Was added, and the mixture was allowed to stand for a whole day and night, and then filtered through a 200-mesh wire mesh whose weight was previously measured.
The insoluble matter was dried at 140 ° C. for 1 hour, cooled at room temperature, and the residual weight was measured (W2) to obtain W1 and W2.
Is calculated by the following formula: gel fraction = W2 / W1 × 100 (%) The gel fraction of the acrylic copolymer used in the present invention is 40% to 80%, more preferably 55%. ~ 75%. When the gel fraction is 40% or less, sufficient secondary processing such as cutting and punching cannot be obtained, and when it is 80% or more, sufficient adhesive force cannot be obtained.

The acrylic aqueous dispersion used in the present invention can be produced by a usual emulsion polymerization method. As a suitable method, for example, an embodiment in which the above-mentioned monomer is used as an emulsifying agent for polymerization using a suitable surfactant and emulsion copolymerization is performed in an aqueous medium can be mentioned.

As the above-mentioned surfactant which can be used in the present invention, each of the usual surfactants used in emulsion polymerization can be used. Further, it is preferable to use a reactive emulsifier having a radical-polymerizable unsaturated group in the molecule because the water resistance of the obtained pressure-sensitive adhesive is improved.

The emulsifier used is not particularly limited, but anionic emulsifiers, nonionic emulsifiers and reactive emulsifiers can be used. As the anionic emulsifier, potassium oleate, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkylphenyl ether sulfate, polyoxy Examples thereof include ethylene alkyl ether phosphate ester, polyoxyethylene alkylphenyl ether phosphate ester, sodium didodecyl diphenyl ether sulfate, and the like. As the nonionic emulsifier, polyoxyethylene alkyl ether,
Examples thereof include polyoxyethylene alkyl phenyl ether, polyoxyethylene oxypropylene block copolymer, and polyethylene glycol fatty acid ester. As the reactive emulsifier, polyethylene glycol mono (meth) having various molecular weights (different EO addition mole numbers) is used.
Acrylate, polyoxyethylene alkylphenol ether (meth) acrylate, polyoxyethylene glycol monomaleic acid ester and its derivatives,
Examples thereof include (meth) acryloyl polyoxyalkylene alkyl ether phosphate. From the viewpoint of environmental hygiene, particularly preferable in terms of environmental hormones, an emulsifier having no polyoxyethylene alkylphenyl ether skeleton is used.

When these surfactants are used as emulsifying agents for polymerization, it is preferable to use them in an appropriate combination, and the amount used is generally 0.1% based on 100 parts by weight in total of the above-mentioned monomers. It is 5 to 3 parts by weight, and more preferably 0.8 to 2 parts by weight.

When the acrylic aqueous dispersion is prepared, a polymerization initiator and a chain transfer agent for controlling the molecular weight may be used. As the polymerization initiator to be used, for example, inorganic peroxides such as potassium persulfate, sodium persulfate, ammonium persulfate and hydrogen peroxide solution are preferable, but other azobisisobutyronitrile, azobisvaleronitrile and other azo System initiator: Organic peroxide system initiators such as benzoyl peroxide, lauroyl peroxide and t-butyl peroxide can also be used. Further, these initiators may be used as a redox initiator in combination with a reducing agent such as tartaric acid, citric acid, L-ascorbic acid, sodium thiosulfate, sodium sulfite, sodium metabisulfite and a metal salt.

Further, when polymerizing each constituent monomer mixture according to a conventional method, it is also possible to use a chain transfer agent such as an organic halide or an alkyl mercaptan as a molecular weight regulator.

The solid concentration of the acrylic aqueous dispersion (A) obtained as described above is not particularly limited, but is usually 55 to 70% by weight.

As the plasticizer used in the present invention, the ones which are particularly preferable for the problem of environmental hormones are trade names of DOA, DIDA, Diasizer 388 and BA manufactured by Mitsubishi Chemical Corporation.
Plasttrit 3431 manufactured by SF Co. and the like can be mentioned.

The amount of the plasticizer according to claim 3 in the water-based pressure-sensitive adhesive composition of the present invention is the same as 100 parts by weight of the acrylic aqueous dispersion (A) as a solid content. One feature is that the solid content is 0.5 parts by weight or more and 5.0 parts by weight or less. If the amount of the plasticizer is less than 0.5 part by weight, sufficient effects on the adhesiveness to nonpolar polymers and curved surface adhesiveness cannot be obtained, and if it is used in excess of 5.0 parts by weight, moisture resistance The heat deterioration property and the cohesive force are reduced, and the white label phenomenon is generated in the thermal paper label, which is not preferable.

The solid content of the plasticizer used in the present invention is preferably 60% by weight or more.

Examples of the adhesive resin as the main component of the emulsion type tackifier (B) used in the present invention include rosin-based, terpene-based and petroleum resin-based adhesive resins, preferably rosin-based adhesive resins. An adhesive resin may be used. Examples of the rosin-based adhesive resin include rosin and derivatives thereof, partially disproportionated or disproportionated rosin, hydrogenated rosin,
In addition to polymerized rosin, rosin maleate, etc., metal salts of these and other esters with diethylene glycol, glycerin, pentaerythritol, etc. are preferably used. The softening point of these adhesive resins is 100 ° C to 16 ° C.
The temperature is 0 ° C, and more preferably 130 ° C to 160 ° C.
If the softening point is less than 100 ° C, sufficient adhesion to the polyolefin film wrap cannot be obtained.

At 160 ° C. or higher, sufficient initial tack (particularly ball tack) and curved surface adhesiveness cannot be obtained. The solid content concentration of these emulsion type tackifiers is not particularly limited, but is usually 50 to 60 parts by weight.

These emulsion type tackifiers may be used alone or in combination of two or more kinds. However, the total solid content of the emulsion type tackifiers is the same as that of the acrylic aqueous dispersion. The content is 3 parts by weight or more and 20 parts by weight or less, more preferably 5 parts by weight or more and 15 parts by weight or less, and further preferably 7 parts by weight or more and 13 parts by weight or less with respect to 100 parts by weight of the solid content.

If the total amount of the emulsion type tackifier is less than 3 parts by weight, sufficient adhesiveness cannot be obtained. Also, 20
If it is more than weight part, sufficient initial tack (ball tack),
Curved surface adhesiveness cannot be obtained.

This pressure-sensitive adhesive composition may further contain a usual crosslinking agent for further improving cohesive strength. Examples of the cross-linking agent include tolylene diisocyanate (TDI), 4.4'-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XD).
I) and other isocyanate cross-linking agents, bisphenol A
Type, bisphenol F type epoxy resin and other emulsions, epoxidized polybutanediene, epoxidized polyisoprene and other epoxidized diene polymer emulsions and other epoxy type cross-linking agents, oxalic acid dihydrazide, malonic acid dihydrazide, adipine Acid dihydrazide, ethylene-
Examples thereof include hydrazine derivatives having at least two hydrazino groups in the molecule such as 1,2-dihydrazine and propylene-1,3-dihydrazine.

In addition, the pressure-sensitive adhesive composition of the present invention may optionally contain various conventionally known additives such as a plasticizer viscosity modifier, a thickener, a filler, a pigment and an antifoaming agent. You may allow it. These additives may be used in the usual amounts applied to this type of pressure-sensitive adhesive composition.

[0031]

The details of the present invention will be described in more detail with reference to the following examples.

The preparation of test pieces and various tests of tack, normal-state adhesive strength, cohesive strength, curved surface adhesiveness, and wet heat deterioration resistance are as follows.
The following method was followed.

(1) Preparation of test piece The pressure-sensitive adhesive layer after drying was 17 ± 1.5 g / m on the release paper.
2. A sample of the pressure sensitive adhesive composition is applied so that
After drying at 100 ° C. for 2 minutes with a hot air circulation dryer, it is transferred to a cast coated paper to prepare a pressure sensitive adhesive sheet.

(2) Adhesion test after normal condition and after wet heat Stainless steel plate or polyethylene plate with PVC wrap,
Suntech film ^{(R )} , Yukarap film ^(R)
The test piece prepared in (1) was attached to each adhered adherend, and the 250 g roller was reciprocated once by reciprocating, and after 5 minutes in an atmosphere of 23 ° C. and 50% RH (relative humidity). After being left at, the adhesive strength (g / 25 mm) is measured under a peeling speed of 300 mm / min.

The sample coated as described above was heated at 50 ° C.-9
After leaving it for 1 week under humidification of 5% RH, take it out and
After leaving it in a constant temperature and humidity room at 23 ° C-50% RH for one day and night,
Similarly, the adhesive strength is measured.

⊚: Film tear or film elongation ◯: 1000 g / 25 mm or more ×: Less than 1000 g / 25 mm (3) Tack test J. According to the Dow method, a slope of 60 ° has a length of 100
A test piece of mm is attached, a steel ball with a diameter of x / 32 inch is rolled from a position 100 mm above the slope, and the size x of the ball with the maximum diameter that stops on the test is displayed.

(4) Cohesive force test # 280 was adhered to a stainless steel plate of SUS304 polished with water resistant abrasive paper so that the adhered area of the test piece was 25 × 25 mm, and a 2 kg roller was reciprocated once. Crimped.
A load of 1 kg is applied to the sample in an atmosphere of 40 ° C.-65% RH, and the time until the load falls is measured.

(5) Curved Surface Adhesion Test A 10 mm × 20 mm test piece was applied to a 12 mm polyethylene rod and a 12 mm glass rod with a Suntech film sprinkled on it, and a 27 mm rod with a 100 mesh nylon net sprinkled on it. Affixed to and placed under room temperature conditions for 24
Observe how the test piece floats from the rod after being left for a period of time.

○: No lift △: Slight lift ×: Complete lift (6) Secondary workability test The coated paper prepared in (1) above was 25 mm wide and 100 m long.
Cut out to a size of m. Sixty test pieces cut out are piled up and cut six times with a cutting machine, and the amount of the adhesive attached to the blade of the cutting machine is measured.

◎: The weight of the adhesive attached to the blade is 20 mg or less ○: The weight of the adhesive attached to the blade is 20 mg to 25 mg Δ: The weight of the adhesive attached to the blade is 25 mg to 30 mg ×: Attached to the blade The weight of the adhesive is 30 mg or more. Next, the present invention will be described in detail with reference to production examples and examples. Parts and% in the examples are parts by weight and% by weight, unless otherwise specified.

Production Example-1 25 parts of water and 0.06 part of sodium persulfate were charged into a reactor equipped with a temperature controller, a stirrer, a reflux condenser, a supply container, and a nitrogen introducing tube. Separately, the following items were prepared as the supply (1).

Feed (1) 2 ethylhexyl acrylate 67.0 parts Butyl acrylate 2 0.5 parts Methyl methacrylate 3.0 parts Vinyl acetate 5.0 parts Acrylic acid 0.5 parts Styrene 2.0 parts Mono ( 2-methacryloyloxyethyl) acid phosphate 0.5 part acrylic acid 2-hydroxypropyl ester 2.0 parts water 52 parts dioctyl sulfosuccinate sodium aqueous solution (trade name Perex OT-P (Kao)) 0.3 parts alkyl ether Aqueous solution of sodium sulfate (trade name Disponyl FES77IS (manufactured by Cognis)) 0.8 part Aqueous solution of sodium alkyl 3-allyl-2-hydroxypropylsulfosuccinate (trade name Latemur S-180A (Kao)) 0.3 part Separately , As a feed (2), 0 parts sodium persulfate in 10 parts water 7 parts was adjusted initiator solution prepared by dissolving.

After the inside of the reactor charged with the above-mentioned initiator solution was replaced with nitrogen gas, the above-mentioned feed (1) was fed into the same reactor.
Was added and the mixture was heated to 90 ° C. Then, 10% of the feed (2) was charged into the reactor, and the rest of the feed (1) and the feed (2) were uniformly charged into the reactor over 3 to 3.5 hours. Supplied. After the end of the supply, the mixture was kept at 90 ° C. for 1.5 hours for emulsion polymerization to obtain a resin aqueous emulsion. The solid content concentration of this copolymer aqueous emulsion was about 62%.

Production Examples-2 to 8 showing the composition of the monomer, the resin concentration of the produced emulsion and the glass transition temperature (calculated value) in Table-1. And the emulsifier composition was changed as shown in Table-1, and a copolymer aqueous emulsion was obtained according to Production Example-1. The results are shown in Table-1. The emulsifiers used other than the emulsifier used in Production Example 1 are shown in Table 1 below.

[0045]

[Table 1]

Examples-1 to 6 and Comparative Examples-1 to 6 Table 2 shows emulsion type tackifiers and plasticizers containing the copolymer aqueous emulsion and tackifier resin as the main components, which were produced in the above Production Examples. The pressure-sensitive adhesive composition was prepared by mixing the mixture at the ratios shown above, and further adding a thickener, an alkaline solution, a pigment, an antifoaming agent and the like and stirring the mixture.

The emulsion type tackifiers used in the examples and comparative examples are as follows.

DS-90: Rosin-based tackifier (softening point 75 to 85 ° C., solid content 50%) SK-508D: Polymerized rosin-based tackifier (softening point about 1
30 ° C, solid content 55%) SK-532D: Polymerized rosin tackifier (softening point about 1
Super ester E-650 manufactured by Harima Chemicals Co., Ltd. (45 ° C., solid content 55%): Polymerized rosin tackifier (softening point: about 150 ° C., solid content 50%) manufactured by Arakawa Chemical Co., Ltd. And the plasticizers used in the comparative examples are as follows.

DIDA (diisodecyl adipate) DOA (di-2-ethylhexyl adipate) Mitsubishi Chemical Co., Ltd. product Platrit 3431 BASF products The above test results will be described using Table 2.

[0050]

[Table 2]

As is known from Table 2, according to Examples 1 to 5 of the present invention, the balance between tack, permanent adhesive force and cohesive force is excellent, that is, the adhesive force to the polyolefin film and the curved surface adhesiveness are good. Yes, cohesive and 2
It can be seen that an aqueous pressure-sensitive adhesive composition excellent in any of the following processability can be obtained.

In Comparative Example 1, since the acrylic copolymer does not have a phosphate group-containing unsaturated monomer unit, the adhesive force to the polyolefin film is low. In Comparative Example 2, the emulsion type tackifier is added. The initial adhesive strength (ball tack) was low because of the large amount, and Comparative Example 3 was measured under heating and humidification because the phosphoric acid group-containing unsaturated monomer unit in the acrylic copolymer was large. The cohesive force of the
The adhesive strength after storage under humidification was also significantly reduced.

Further, Comparative Example 4 is Tg of an acrylic copolymer.
The initial adhesive strength and the curved surface adhesive strength were insufficient because of high, and in Comparative Example 5, the emulsion-type tackifier had a low softening point, and therefore the adhesive strength to the polyolefin film was very low. Comparative Example 6 is a Tg of an acrylic copolymer.
The secondary workability was not good due to the low value.

Continued front page    (72) Inventor Noriyoshi Kato             653-2 Rokuromi, Yokkaichi-shi, Mie BIA             SF Dispersion Co., Ltd. F term (reference) 4J040 DE001 DF011 DF041 DF051                       DF081 DF091 DG001 GA27                       JA03 JB09 LA02 LA06 MA02                       MA04 MA05 MA10 MA11                 4J100 AJ02Q AJ08Q AL03P AL04P                       AL05P AL08R AP07R BA64                       CA04 JA03

Claims (3)

[Claims] 1. (A) (a) 0.2 to 5% by weight of a carboxyl group-containing unsaturated monomer, (b) 0.2 to 1% by weight of a phosphate group-containing unsaturated monomer, (c) Acrylic acid has 4 to 4 carbon atoms
Copolymerized with 55 to 99.4% by weight of an alkyl ester in the range of 18 and (d) 0.1 to 38.8% by weight of another unsaturated monomer copolymerizable with these unsaturated monomers. An acrylic aqueous dispersion comprising the acrylic copolymer obtained as described above, wherein the glass transition temperature (calculated value) of the acrylic copolymer is -30 ° C to -65 ° C. Body, and (B) 100 parts by weight of the acrylic aqueous dispersion as a solid content relative to 100 parts by weight.
A water-based pressure-sensitive adhesive composition, characterized in that an emulsion-type tackifier mainly composed of an adhesive resin having a softening point of 60 ° C. is also mixed in a solid content of 3 parts by weight or more and 20 parts by weight or less. 2. The gel fraction of the acrylic copolymer is 40% to
The water-based pressure-sensitive adhesive composition according to claim 1, which is 80%. 3. Acrylic aqueous dispersion having a solid content of 100 parts by weight and a plasticizer having a solid content of 0.
Claim 1 which contains 5 weight part or more and 5.0 weight part or more.
The water-based pressure-sensitive adhesive composition according to any one of 1 and 2 above.