JP2000313864A - Aqueous pressure-sensitive adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous pressure-sensitive adhesive composition having a good adhesion performance and water resistance, and an adhesive product using the same. SOLUTION: This aqueous pressure-sensitive adhesive composition contains a polymer emulsion obtained by polymerizing a monomer mixture containing (a) 50 wt.% or more alkyl (meth)acrylate wherein the carbon number of the alkyl group is from 9 to 14 and (b) from 0.2 to 2.5 wt.% α,β-unsaturated carboxylic acid in an aqueous system in the presence of from 10 to 500 ppm radical chain transfer agent based on the total monomer and using from 500 to 5,000 ppm organic peroxide initiator and from 50 to 1,000 ppm water-soluble initiator based on the total monomers. An adhesive product is prepared by forming an adhesive layer from this aqueous pressure-sensitive adhesive composition on one or both sides of a base material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based pressure-sensitive adhesive composition having excellent adhesion performance and water resistance to non-polar adherends, and an adhesive product obtained using the same.

[0002]

2. Description of the Related Art From the viewpoints of improving the global environment and working environment and effectively utilizing resources, there is a demand for conversion from a solvent type adhesive to an aqueous emulsion type adhesive. As these pressure-sensitive adhesives, pressure-sensitive adhesives having a suitable adhesive strength for a transparent film label, a pressure-sensitive adhesive tape and the like, and strongly adhering to a non-polar adherend such as polyethylene or polypropylene are required. Labels and tapes attached to various adherends are required to maintain their adhesive strength and shape over time even when stored under high humidity or high temperature, especially in bathrooms and kitchens. The label on the used detergent bottle has a high degree of water resistance and adhesiveness due to the fact that it often comes into contact with water or detergent aqueous solution under high temperature and high humidity, and the mechanical force is added by squeezing. Is required.

However, conventional aqueous emulsion-type pressure-sensitive adhesives containing an alkyl (meth) acrylate having an alkyl group of 8 or less carbon atoms as a main component are particularly disadvantageous in terms of environmental resistance such as moisture resistance, water resistance and heat resistance. Inferior to solvent type. For this reason, in the field where a high degree of environmental resistance is required, the solvent type is frequently used, and the conversion to the aqueous emulsion type pressure sensitive adhesive is not sufficiently advanced.

An object of the present invention is to provide a water-based pressure-sensitive adhesive composition having good adhesive performance and water resistance, and an adhesive product using the same.

[0005]

According to the present invention, there are provided (a) an alkyl (meth) acrylate having an alkyl group having 9 to 14 carbon atoms (hereinafter referred to as a component (a)) at least 50% by weight; β-
A monomer mixture containing 0.5 to 2.5% by weight of an unsaturated carboxylic acid (hereinafter referred to as "component (b)") is added in an amount of 10 to
In the presence of 500 ppm of a radical chain transfer agent, an aqueous peroxide is used by using 500 to 5000 ppm of an organic peroxide-based initiator based on all monomers and 50 to 1000 ppm of a water-soluble initiator based on all monomers. The present invention provides a water-based pressure-sensitive adhesive composition containing a polymer emulsion obtained by polymerizing with a pressure-sensitive adhesive, and a pressure-sensitive adhesive product having a pressure-sensitive adhesive layer formed from this water-based pressure-sensitive adhesive composition provided on one or both surfaces of a substrate. .

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The alkyl group of the component (a) used in the present invention may be linear or branched, and the number of carbon atoms is determined from the viewpoint of improving adhesion to non-polar materials such as polyolefin.
9 or more, preferably 10 or more, more preferably 11 or more, the number of carbon atoms is 14 or less, preferably from the viewpoint of low-temperature adhesion.
It is 13 or less, more preferably 12 or less. As the component (a), for example, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate,
Isodecyl (meth) acrylate, undecyl (meth)
Acrylate, isoundecyl (meth) acrylate,
Dodecyl (meth) acrylate, isododecyl (meth)
Acrylate, tridecyl (meth) acrylate, isotridecyl (meth) acrylate, tetradecyl (meth) acrylate, isotetradecyl (meth) acrylate, and the like are used, and these are used alone or in combination of two or more. The content of the component (a) in the monomer mixture is 50% by weight or more, preferably 70% by weight or more, and more preferably 80% by weight or more, from the viewpoint of improving the adhesion to non-polar materials.

The component (b) used in the present invention has 3 carbon atoms.
To 5, α, β-unsaturated carboxylic acids are preferred, and specific examples include acrylic acid, methacrylic acid, and itaconic acid. The content of the component (b) in the monomer mixture is 0.5% from the viewpoint of improving the mechanical stability of the polymer emulsion.
It is at least 2.5% by weight, preferably at most 2% by weight, from the viewpoint of not deteriorating the adhesion to non-polar materials and the water whitening resistance. Further, use of acrylic acid is most desirable from the viewpoint of achieving both mechanical stability and water whitening resistance.

Further, the monomer mixture of the present invention may contain a monomer copolymerizable with the above components (a) and (b) (hereinafter, referred to as component (c)). As the component (c), lower alkyl (meth) acrylates having 8 or less carbon atoms in the alkyl group, hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, and long-chain alkyl (meta) having 15 or more carbon atoms in the alkyl group Acrylates, vinyl esters such as vinyl acetate, aromatic vinyls such as styrene,
Examples thereof include nitrile monomers such as acrylonitrile and amide monomers such as acrylamide, and lower alkyl (meth) acrylate, hydroxyalkyl (meth) acrylate and vinyl ester are preferable.

The content of the component (c) in the monomer mixture is preferably 49.5% by weight or less, more preferably less than 30% by weight, particularly preferably less than 20% by weight, from the viewpoint of improving the adhesion to non-polar materials. . If necessary, an internally crosslinkable monomer such as divinylbenzene or ethylene glycol methacrylate may be used in a proportion of 2% by weight or less based on all monomers.

In the production of the polymer emulsion according to the present invention, polymerization is carried out in the presence of a radical chain transfer agent using two kinds of initiators, an organic peroxide initiator and a water-soluble initiator. The organic peroxide-based initiator relates to the generation of the gel component in the polymer component, and the larger the amount used, the larger the generation amount of the gel component. When the amount of gel in the polymer component is increased, the cohesive strength of the polymer is increased and the holding power and the punching workability of the adhesive product are improved, but on the other hand, the polymer fluidity is reduced and the rough surface adhesion is reduced. This leads to a decrease in adhesive strength. The radical chain transfer agent is related to the molecular weight of the polymer component.If the amount used is increased, the molecular weight of the polymer component is reduced, the polymer fluidity is improved, the rough surface adhesion is improved, and the adhesive strength can be improved, On the other hand, the cohesive strength is weakened, and the holding power, the punching workability of the adhesive product, and the like are deteriorated. Even if the radical chain transfer agent and the organic peroxide-based initiator are each used alone, even if the amounts thereof are optimized, a sufficiently satisfactory adhesive performance cannot be obtained, and the radical chain transfer agent and the organic peroxide-based initiator cannot be used. By appropriately setting the amount of each combination and combination, both the polymer cohesive strength and the adhesive strength can be achieved.

The amount of the radical chain transfer agent used in the present invention is 10 ppm with respect to all monomers from the viewpoint of improving the adhesive strength.
The content is preferably at least 50 ppm, more preferably at least 100 ppm, and is at most 500 ppm, preferably at most 400 ppm, from the viewpoint of improving the holding power, the curved surface adhesion, and the punching workability of the pressure-sensitive adhesive product. Examples of the radical chain transfer agent include (iso) butyl mercaptan, (iso) octyl mercaptan, (iso) decyl mercaptan, and (iso)
Alkyl mercaptans having 3 to 32 carbon atoms such as dodecyl mercaptan, octyl thioglycolate, thioglycolates such as 2-ethylhexyl thioglycolate, β-mercaptopropionic acid and esters thereof,
Disulfides such as isopropyl xanthogen disulfide; 2,4-diphenyl-4-methyl-1-pentene; 1-methyl-4-isopropylidene-1-cyclohexene;

In the present invention, the amount of the organic peroxide initiator used is 500 p.
pm or more, preferably 1000 ppm or more, more preferably 2000 ppm
ppm or more, and from the viewpoint of improving the adhesive strength, 5000 ppm
Or less, preferably 4000 ppm or less. As organic peroxide initiators, diacyl peroxides such as benzoyl peroxide, lauroyl peroxide, decanoyl peroxide, dialkyl peroxides such as t-butyl cumyl peroxide, dicumyl peroxide, t
Peroxyesters such as -butylperoxylaurate and t-butylperoxybenzoate; hydroperoxides such as cumene hydroperoxide and paramenthane hydroperoxide; peroxyketals; and ketone peroxides. .

[0013] The water-soluble initiator forms fine polymer particles by radically attacking the micelle particles solubilizing the monomer. Therefore, the water-soluble initiator is related to the average particle size of the polymer particles, and increasing the amount of the water-soluble initiator reduces the average particle size of the polymer particles. Originally, the water-whitening resistance of the emulsion-type pressure-sensitive adhesive is advantageous when the average particle size of the polymer particles is small, but when the amount of the water-soluble initiator exceeds an appropriate amount, the water-soluble initiator itself adversely affects the water-whitening resistance. Poor water whitening resistance. Therefore, the amount of the water-soluble initiator used is 50 ppm or more, preferably 100 ppm or more, with respect to all monomers, from the viewpoint of reducing the average particle size, and from the viewpoint of preventing the effect of the water-soluble initiator itself, 1000 ppm. Below, preferably 500p
pm or less.

In the present invention, from the viewpoint of reducing the average particle size of the polymer particles, the initiation of polymerization of micelle particles by the water-soluble initiator precedes the initiation of polymerization of monomer particles by the organic peroxide-based initiator. desirable. Therefore, the water-soluble initiator is desirably one that is more easily decomposed at a lower temperature than the organic peroxide-based initiator, and has a 10-hour half-life of 70 ° C.
Or less, preferably 60 ° C. or less. Examples of the water-soluble initiator of the present invention include persulfates such as ammonium persulfate and 2,2-azobis [2- (2-imidazoline-2-).
Il) propane] water-soluble azo initiators such as dihydrochloride and the like. Redox systems in which a sulfite is combined with a persulfate and redox systems in which ascorbic acid is combined with a t-butyl hydroperoxide are exemplified. This is preferable because radicals can be generated at a low temperature.

As a method for obtaining a polymer emulsion according to the present invention, a known polymerization method can be applied. However, in the case of a monomer system containing a large amount of a poorly water-soluble long-chain alkyl (meth) acrylate, an aqueous emulsifying dispersant solution is used. It is desirable to use a method in which the monomer is used to make the particles fine, and then copolymerization is performed in the presence of a polymerization initiator. In a normal emulsion polymerization method using a micelle as a polymerization site, it is difficult to obtain a stable polymer emulsion when a poorly water-soluble long-chain alkyl (meth) acrylate is used as a raw material. A polymer emulsion having good stability can be obtained. Less than,
A method in which a monomer is micronized using an aqueous solution of an emulsifying dispersant (a step of emulsifying and dispersing a monomer) and then copolymerizing in the presence of a polymerization initiator (a polymerization step) will be described as an example.

As the emulsifying and dispersing agent used in the production of the polymer emulsion according to the present invention, anionic and nonionic surfactants can be used. For example, as described in page 4 of JP-A-6-192341. Emulsifying dispersants. Further, the polymerizable emulsifying dispersant can be used alone or in combination with the above emulsifying dispersant. When a polymerizable emulsifying dispersant is used, water resistance and moisture resistance can be improved as compared with ordinary emulsifying dispersants. The polymerizable emulsifying dispersant usable in the present invention has a radical polymerizable double bond such as an allyl group, a (meth) acrylic acid group, a styrene group and an isopropenyl group in the molecule. And reactive emulsifying dispersants described on page 2 of JP-A-255411. The amount of the emulsifying dispersant used is preferably 0.5% by weight or more, more preferably 1% by weight or more based on all monomers, from the viewpoint of emulsion stability. From the viewpoint of water resistance, the content is preferably 10% by weight or less, more preferably 5% by weight or less, and particularly preferably 3% by weight or less.
% By weight or less is preferred.

In the step of emulsifying and dispersing the monomer, the monomer and the aqueous solution of the emulsifying dispersant are blended, and the average particle size of the monomer fine particles is preferably 0.1 to 0.5 μm, more preferably 0.3 to 0.5 μm.
Emulsify and disperse to 0.4 μm. It takes a long time to emulsify and disperse,
The average particle size is preferably 0.1 μm or more from the problem that the viscosity of the emulsion is high and handling is difficult.
From the viewpoint of improving the water resistance, the thickness is preferably 0.5 μm or less.
It is desirable to add the radical chain transfer agent to the monomer before emulsification. When the polymer concentration is less than 5% by weight, there is a problem in economy, and when the polymer concentration exceeds 80% by weight, the production ratio becomes difficult because the emulsion viscosity becomes high.
The total amount of the monomers is preferably from 5 to 80% by weight, more preferably from 30 to 60% by weight, based on the entire polymerization system. In the step of emulsifying and dispersing the monomer, an emulsifying machine such as an ultrasonic homogenizer, a homomixer, a milder, an attritor, a (ultra) high-pressure homogenizer, and a colloid mill can be used.

In the polymerization step, the monomer emulsion is charged into a polymerization vessel equipped with a stirrer, a polymerization initiator is added thereto, and the polymerization reaction is started by heating to an appropriate polymerization temperature. At this time, the polymerization system is desirably purged with an inert gas such as nitrogen in order to prevent the polymerization from being inhibited by oxygen. It is desirable that the organic peroxide-based initiator be added and dissolved in the monomer before emulsification in advance. The water-soluble initiator is preferably added to the polymerization system after charging the monomer emulsion into a polymerization vessel and purging with an inert gas.

[0019] The polymerization temperature is preferably in the range of 40 to 90 ° C.
Further, the polymerization time is appropriately 1 to 10 hours. The particle size of the polymer emulsion obtained through the emulsification and dispersion step and the polymerization step is preferably 0.1 μm or more in order to obtain an appropriate viscosity, and 0.3 μm from the viewpoint of improving the water-resistant whitening property.
m or less is preferable.

The tetrahydrofuran (THF) soluble component of the polymer component of the polymer emulsion according to the present invention is:
From the viewpoint of improving the adhesive strength, the content is preferably 50% by weight or more, more preferably 60% by weight or more. Further, from the viewpoint of improving cohesive force relating to holding power and curved surface adhesiveness, it is preferably at most 90% by weight, more preferably at most 80% by weight. The weight-average molecular weight of the THF-soluble component is preferably 700,000 or less, more preferably 600,000 or less, particularly preferably 500,000 or less, from the viewpoint of improving the adhesive strength. Further, from the viewpoint of improving the cohesive strength, it is preferably at least 250,000, more preferably at least 350,000.

The pressure-sensitive adhesive product of the present invention is produced by applying the water-based pressure-sensitive adhesive composition comprising the polymer emulsion obtained as described above on one or both surfaces of a substrate and drying to form a pressure-sensitive adhesive layer. In, for example, surface protection film, coating masking tape, adhesive tape,
Adhesive labels and the like. The thickness of the adhesive layer is 1 to 10
Preferably, it is set to 0 μm. As the substrate, a sheet of polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyester resin, or the like is suitably used.

The adhesive product of the present invention has an adhesive force and a strong cohesive force suitable for various uses, and can exhibit high adhesiveness and good curved surface adhesion to non-polar adherends such as polyethylene. And very good workability such as label punching properties. Furthermore, the adhesive performance does not change with time even when placed at high temperature or high humidity, and the water whitening resistance is extremely good even under bad conditions in which the film label is directly immersed in water.

[0023]

Examples 1 to 6 and Comparative Examples 1 to 8 A raw material monomer, an organic peroxide-based initiator and a radical chain transfer agent shown in Table 1 were charged into a glass container and uniformly dissolved.
The ion-exchanged water containing the emulsifying dispersant in the amount shown in Table 1
50 g were mixed and treated with a high-pressure homogenizer (manufactured by Izumi Food Machinery) for 5 minutes to prepare an emulsion. The average particle size of the monomer in this emulsion was measured using a HORIBA particle size analyzer (LA-910 type) and is shown in Table 1. This emulsion was transferred to a reactor, the internal temperature was adjusted to 35 ° C., and after purging with nitrogen gas, a water-soluble initiator shown in Table 1 was added thereto. The mixture was heated with stirring and heated for 2 hours until the internal temperature reached 85 ° C., and then aged at the same temperature for 6 hours to complete the polymerization. After cooling, 28% aqueous ammonia was added to adjust the pH to 7.0 to 7.5, and the mixture was filtered through a 500-mesh stainless steel mesh to take out a polymer emulsion.
The average particle size, mechanical stability, THF-soluble matter, and weight-average molecular weight of the THF-soluble matter of the obtained polymer emulsion were measured by the following methods. Table 2 shows the results.

The obtained polymer emulsion was used as a biaxially oriented polypropylene (PP) film (Toray Torayfan BO, thickness 50 μm) or a polyethylene terephthalate (PET) film (Toray Lumirror S105, thickness 50 μm).
m) is applied to the corona-treated surface using a coating machine (Multicoater, M200) manufactured by Hirano Tecseed Co., Ltd. so that the thickness of the adhesive layer becomes 25 μm, and then dried at 100 ° C. for 1 minute.
Release film made of polyester resin (manufactured by San-A Kaken:
ID-8, thickness 38 μm) to prepare an adhesive sheet. The physical properties of the obtained pressure-sensitive adhesive sheet were evaluated by the following methods. Table 3 shows the results.

(1) Average particle size of polymer emulsion Measured using a particle size analyzer made by HORIBA (LA-910) and expressed as a volume average particle size.

(2) Mechanical stability Measured according to JIS K 6828 (1996) test method under the following conditions. Load: 5 kg, rotation time: 5 minutes, filter wire mesh: stainless steel wire mesh (200 mesh) This measurement value is shown by weight% of agglomerate with respect to solid content of emulsion, and the lower the value of this weight%, the more mechanical stability Means good.

(3) THF-soluble content Teflon flat plate with a capacity of 25 mL (TERAOKA flat plate: model number CW16025)
Put 0.5g of polymer emulsion in the oven, 23 ℃, humidity 60%
The polymer film was formed by being allowed to stand in an RH room for 48 hours.
Next, coat the above coating on a 100 mL screw tube (Maruem No. 7).
0.2 g is precisely weighed and added with 80 mL of THF and added to 23-2.
The THF-soluble polymer was extracted by shaking at a temperature of 6 ° C. for 24 hours. Thereafter, the mixture was filtered through a 200-mesh stainless steel wire net to separate and remove the gel component. The extract was evaporated to dryness, and the weight of the residual polymer was measured to determine the weight of the THF-soluble polymer. The THF soluble content was determined by the following formula.

THF-soluble matter (%) = (weight of THF-soluble polymer / total weight of collected polymer) × 100 (4) Weight-average molecular weight of THF-soluble matter The weight-average molecular weight was measured under the following GPC analysis conditions. (In terms of polystyrene). GPC analysis conditions: Column: GMHXL (manufactured by Tosoh: 7.8 mm x 300 mm) Directly connected to two eluents: 50 μmol-CH ₃ COOH / THF (flow rate: 1 mL / min) Detector: RI Sample concentration: 2 mg / mL, injection volume: 100 μL (5) Adhesive force Measured according to JIS Z 0237-1991. High-density polyethylene plate (PE) and stainless plate [SUS304 / Abrasive paper (#
280) and a 25mm wide adhesive sheet (substrate: PP film), and left for 24 hours at 23 ° C / 65% RH, then 180 ° peel strength (peel rate: 300mm / min) Was measured.

(6) Holding force A pressure-sensitive adhesive sheet (substrate: PP film) is adhered to the high-density polyethylene plate and the stainless steel plate in an area of 25 mm × 25 mm, and peeled off under a condition of 70 ° C. under a load of 1000 g. The time until was measured. In the case of holding for 3 hours, the deviation width was measured. When there was no deviation, it was described as NC.

(7) Water Whitening Resistance After the adhesive layer of the adhesive sheet (substrate: PP film, 45 mm × 50 mm) is immersed in tap water at a temperature of 23 to 25 ° C. for 24 hours, a PET film (East Rell Miller S105) , 50 μm), and the whitening degree (haze value%) of the pressure-sensitive adhesive sheet was measured with a reflection / transmittance meter [HR-100: manufactured by Murakami Color Research Laboratory Co., Ltd.].

(8) Curved Surface Adhesive sheet (substrate:
(PET film) 2 was stuck, stored at 40 ° C./24 Hr / 40% RH, and evaluated according to the evaluation criteria shown in FIG.

(9) Paste-removing property A cut is made vertically from the center point to the side of the adhesive sheet (substrate: PET film, 50 mm × 50 mm) with a cutter knife, and the cut is made with a Tensilon tensile tester (speed: 300 mm / min).
Pull it up by 20mm while tearing the cut. At this time, the maximum length of the stringing of the glue generated in the tear of the base film was read, and this was used as the substitute property of the glue breaking property.
From the average value of the results of performing the above test five times, the adhesiveness was determined according to the following criteria. Stringing 2 mm or more: ×, 1-2 mm: △, 1 mm or less: ○, almost none: ◎

[0033]

[Table 1]

The abbreviations in the table have the following meanings. Monomer LMA: n-lauryl methacrylate NMA: n-nonyl methacrylate TDMA: isotetradecyl methacrylate AA: acrylic acid MAA: methacrylic acid 2EHA: 2-ethylhexyl acrylate MMA: methyl methacrylate BA: butyl acrylate Radical chain transfer agent DM: n-dodecyl Mercaptan MPA: β-mercaptopropionic acid TGA: thioglycolic acid TGAO: n-octyl thioglycolate Organic peroxide initiator BPO: Benzoyl peroxide CPO: Cumyl peroxyoctate Water-soluble initiator tBHP: t-butylhydro Peroxide AsA: L-ascorbic acid APS: Ammonium persulfate SBS: Sodium bisulfite VA044: VA-044 [Azo-based water-soluble initiator manufactured by Wako Pure Chemical Industries, Ltd.] Emulsifier and dispersant S180: Latemul S-180 [Kao ( Co., Ltd., reactive surfactant] S180A: Latemul S-18 0A [Reactive surfactant made by Kao Corporation] WZ: Levenol WZ [ethoxy sulfate surfactant made by Kao Corporation]

[0035]

[Table 2]

[0036]

[Table 3]

[0037]

According to the present invention, a water-based pressure-sensitive adhesive composition having excellent adhesive performance and water resistance is provided. In addition, it has an adhesive force and a strong cohesive force suitable for various uses, such as polyethylene. The present invention provides a pressure-sensitive adhesive product exhibiting high tackiness, good curved surface adhesion, and workability with respect to non-polar adherends. Further, the adhesive performance does not change with time even when stored under high temperature or high humidity, and the water resistance is extremely good even under the bad condition of being immersed in water.

[Brief description of the drawings]

FIG. 1 is a diagram showing evaluation criteria for curved surface adhesiveness.

[Description of Signs] 1 High density polyethylene rod 2 Adhesive sheet

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshitaka Sakuta 1334 Minato, Wakayama City, Wakayama Prefecture Inside the Kao Research Institute (72) Inventor Kenichi Shiba 1334 Minato, Wakayama City, Wakayama Prefecture Kao Research Institute F-term (reference) 4J004 AA10 AB01 CA04 CA05 CA06 CC02 FA01 FA04 FA06 4J011 AA05 BB02 JB22 JB26 KA02 KA10 KB22 KB29 NB04 4J040 DF041 DF051 GA07 HA256 HB41 HC24 JA03 JA09 JB09 KA11 KA18 LA01 LA03 LA06 LA04 MA07 QA01 DA04 FA20 JA03

Claims (4)

[Claims] (1) 50% by weight or more of an alkyl (meth) acrylate having 9 to 14 carbon atoms in an alkyl group;
A monomer mixture containing 0.5-2.5% by weight of β-unsaturated carboxylic acid is added in the presence of 10-500 ppm of radical chain transfer agent to 500-5000 ppm of total monomer. Organic peroxide-based initiator and 50-1000pp for all monomers
A water-based pressure-sensitive adhesive composition comprising a polymer emulsion obtained by polymerization in a water-based system using m. 2. The polymer component in the polymer emulsion has a tetrahydrofuran-soluble content of 50 to 90% by weight and a tetrahydrofuran-soluble component having a weight average molecular weight of 250,000 to 250,000.
The water-based pressure-sensitive adhesive composition according to claim 1, wherein the amount is 700,000. 3. The water-based pressure-sensitive adhesive composition according to claim 1, wherein the average particle size of the polymer component of the polymer emulsion is 0.1 to 0.3 μm. 4. A pressure-sensitive adhesive product comprising a pressure-sensitive adhesive layer formed from the water-based pressure-sensitive adhesive composition according to any one of claims 1 to 3 provided on one or both surfaces of a substrate.