JP2601481B2 - Aqueous dispersion type acrylic pressure-sensitive adhesive composition - Google Patents

Description

The present invention relates to an aqueous dispersion type acrylic pressure-sensitive adhesive composition useful for forming an adhesive layer in, for example, pressure-sensitive adhesive tapes, films, sheets and other pressure-sensitive adhesive products. The present invention also relates to an aqueous dispersion type acrylic pressure-sensitive adhesive composition which has excellent balance of excellent adhesive force including its long-term retention and excellent cohesive force which is hardly compatible with these characteristics, in addition to excellent adhesiveness.

More specifically, the present invention relates to (A) an aqueous emulsion copolymer of an acrylic monomer mixture, which has a glass transition point of -30 ° C or less and a gel content in the copolymer of 40% by weight or more. An acrylic copolymer and (B) the following surfactants (i) to (ii) per 100 parts by weight of the (A) acrylic copolymer: (i) a nonionic surfactant having an HLB value of 14 or less; Anionic surfactants (excluding sulfosuccinate anionic surfactants) and / or an HLB value of 14
A surfactant having a HLB value of 14 or less, wherein the nonionic surfactant having a HLB value of 14 or less accounts for 60 to 99% by weight.
An aqueous dispersion type acrylic pressure-sensitive adhesive composition comprising 4 parts by weight and (ii) 0 to 3.5 parts by weight of a sulfosuccinate anionic surfactant.

Water-dispersed pressure-sensitive adhesives are attracting attention because of the environmental hygiene problems associated with the use of organic solvents. It is extremely difficult to combine the three factors of adhesive force (peeling resistance from the adherend), tack (instantaneous wetting to the adherend) and cohesive force (creep resistance) in a well-balanced manner. In particular, the conventional aqueous dispersion-type pressure-sensitive adhesive tends to have insufficient cohesion. However, if the cohesive force is to be improved, the adhesive force, which is a property incompatible with this, is extremely reduced. However, there has been a technical problem that even if the above conditions can be provided in a relatively good balance, the adhesive strength deteriorates to a level that cannot be put to practical use in a relatively short period of time.

For example, Japanese Patent Application Laid-Open No. 49-96063 discloses a resin emulsion obtained by using one or more monomers having a functional group capable of copolymerizing with an acrylic monomer and capable of self-reacting or reacting with each other as an essential component. Japanese Patent Application Laid-Open No. 50-82138 discloses that the pressure-sensitive adhesive component is a copolymer obtained by copolymerization (preferably emulsion copolymerization) using dihinyl and / or diallyl monomer as an essential component. In addition, JP-B-49-4541 describes that a monomer mixture containing an unsaturated carboxylic acid and an allyl compound having two or more allyl groups as essential components is obtained by emulsion polymerization. A pressure-sensitive adhesive comprising a copolymer and a specific amount of a weak salt of a divalent or trivalent metal is disclosed.

The first proposal relates to a method for producing a non-transferable pressure-sensitive sheet using an adhesive which is set and blended so that the desired adhesive strength and internal strength can be maintained after crosslinking or curing by heating. However, according to the study of the present inventors, in the pressure-sensitive adhesive of the first proposal, types of the above-mentioned monomers having a self- or mutually heat-reactive functional group, a combination thereof, and use thereof are described. The selection of the amount and the like is extremely difficult, and even in the specific range of the first proposal, the adhesion or cohesion is often insufficient, and it has been difficult to combine the two in a well-balanced manner. Similarly, it has not been easy for the pressure-sensitive adhesives of the second and third proposals to have a good balance of adhesion and cohesion as in the case of the first proposal.

The present inventors have studied to develop a composition capable of overcoming the technical deficiencies of the conventional aqueous dispersion type acrylic pressure-sensitive adhesive composition as described above.

As a result, an aqueous emulsion copolymer of the acrylic monomer mixture, which satisfies the specific glass transition point condition and the gel content condition (A), and satisfies the specific range amount Aqueous dispersion-type acrylic pressure-sensitive adhesive composition that satisfies the binding requirements of combination surfactant (B) containing a nonionic surfactant with a low HLB value, which has a low main component amount, has an initial adhesive strength and a long term It has been discovered that a pressure-sensitive adhesive composition having a good balance of excellent cohesive force, which is hardly compatible with these properties, together with excellent adhesive strength and excellent tack including retention properties, is provided. As far as the present inventors know, the combination surfactant (B) (i) containing the above-mentioned nonionic surfactant having a low HLB value as the main component amount is contained only in a small amount such as the above-mentioned specific range amount. Aqueous dispersion-type acrylic pressure-sensitive adhesive compositions have not been known. The combination surfactant (B) (i) and the sulfosuccinate ester-based anionic surfactant (B) (ii) form an aqueous emulsion of an acrylic copolymer, which is a main component of the adhesive composition. It is derived from a surfactant used as an emulsifier for polymerization in a process obtained by copolymerization, and a surfactant which is added later if necessary. Therefore, the above-mentioned acrylic copolymer is combined with the above-mentioned combination surfactant (B)
Part or all of (i), preferably (B) (i)
All are copolymerized using the emulsifier for polymerization. It is not possible to carry out aqueous emulsion copolymerization of an acrylic copolymer using such a surfactant (B) (i) having a low HLB value of a nonionic surfactant as a main component as a polymerization emulsifier. It was not previously known. This is because nonionic surfactants having such a low HLB value are used at the polymerization temperature generally used in aqueous emulsion polymerization for industrial use, for example, oils such as acrylic monomers and persulfates at a temperature of 60 ° C. or higher. It is considered that the emulsifying power becomes extremely poor particularly in the presence of a polymerization initiator such as the above, and generally a large amount of coagulated material tends to be generated in the process of aqueous emulsion polymerization. For example, synthetic resin emulsion [Polymer Publishing Co., Ltd.] (19
In “Table 8 Surfactants Used for Emulsion Polymerization” (page 121) in “3. Surfactants Used for Emulsion Polymerization” (page 121), polyacrylic esters In the column of “Polyoxyethylene (P)
= 30-50) alkyl allyl ethers ”, and as anions“ AES ”(alkyl ether sulfate),“ AS ”
(Alkyl sulfate) and the like. The above nonionic surfactant "polyoxyethylene (P = 30 to
The HLB value of “50) alkyl allyl ether” is about 17 to about 18 according to the measurement method described later, and this value is mainly due to the combination surfactant (B) (i) of the present application. Compared to the HLB value of the nonionic surfactant used,
Much larger.

According to the study of the present inventors, the acrylic copolymer (A) which satisfies the above-mentioned conditions at the same time and a surfactant which is conventionally known as a guideline for a surfactant in an aqueous dispersion type acrylic pressure-sensitive adhesive composition are completely known. Conventional water-dispersed acrylic pressure-sensitive adhesives can be used if the requirements for binding to a combined surfactant (B) containing the main component of a non-ionic surfactant with a low HLB value, which has not been obtained, are satisfied. Depending on the agent composition,
Aqueous dispersion-type acrylic pressure-sensitive adhesive composition that has excellent initial adhesive strength and long-term retention that could not be achieved, excellent tack, and excellent properties in cohesion that is incompatible with these properties in a well-balanced manner. I learned that things can be provided.

Accordingly, an object of the present invention is to provide an aqueous dispersion type acrylic pressure-sensitive adhesive composition which has been significantly improved.

The above objects and many other objects and advantages of the present invention will become more apparent from the following description.

In the aqueous dispersion type acrylic pressure-sensitive adhesive composition of the present invention, the aqueous emulsion copolymer of the acrylic monomer mixture has a glass transition point of -30 ° C or lower and is contained in the copolymer. An acrylic copolymer (A) having a gel content of 40% by weight or more is contained as a resin component.

Although the composition of the acrylic monomer mixture is not particularly limited, the following monomer compositions (a) to (c) (a) Formula CH ₂ = CH-COOR ¹ wherein R ¹ represents a C ₂ -C ₁₀ linear or branched alkyl group, and the homopolymer has a glass transition point (Tg ₁ ) of −20. ℃ acrylate monomer 99.9 wt% or less (b) alpha of C ₃ -C _5, β- unsaturated mono- - or di - carboxylic acid monomer 0.1 to 5% by weight and (c) above (B) a monomer copolymerizable with the monomer and the (b) monomer, wherein the comonomer other than the (a) monomer and the (b) monomer is 0 to 50% by weight; Is preferably an acrylic monomer mixture comprising 100% by weight in total.

In an acrylic monomer mixture comprising a total of 100% by weight of the above monomer compositions (a) to (c), the formula CH ₂ = CH—COO
R ¹ , the glass transition temperature of the homopolymer is -20 ℃
R ¹ of the following acrylate monomer (a) is C ₂ to
Represents a linear or branched alkyl group of C ₁₀ , preferably C ₂ -C ₉ , examples of such a group R ¹ being an ethyl group, n-
Examples thereof include a propyl group, an n-butyl group, an n-hexyl group, a 2-ethylhexyl group, an n-octyl group, an isooctyl group, and an isononyl group. Further, specific examples of the acrylate monomer (a) include ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, Nonyl acrylate and the like can be exemplified.

The amount of the acrylate monomer (a) used is, for example, 50 to 99.9% by weight, preferably 63 to 95% by weight, based on 100% by weight of the total of the above monomer mixture.

By using the acrylate monomer (a) in an amount of at least the above lower limit, a good balance between excellent adhesive strength and excellent tack and excellent cohesive strength is achieved.
By using the above-mentioned upper limit amount or less, the mechanical stability of the dispersion of the aqueous emulsion copolymer (the stability of the dispersion when shearing force is applied) is good, and the dispersion is also excellent in cohesion. By appropriately selecting and using the amount in the use amount range, it is possible to achieve a good balance between excellent adhesive strength and excellent tack and excellent cohesive strength.

Further, in an acrylic monomer mixture consisting of a total of 100% by weight of the monomer compositions (a) to (c), α of C ₃ -C ₅ ,
β-unsaturated mono- or di-carboxylic acid monomer (b)
The use of is preferred. Specific examples of such a monomer (b) include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, citraconic acid, and the like. Of these, acrylic acid, methacrylic acid, and itaconic acid are more preferably used.

The amount of the monomer (b) used is based on the total amount of the monomer mixture.
In 100% by weight, for example, 0.1 to 5% by weight, preferably 0.2 to 5% by weight.
1.5% by weight. When the amount of the monomer (b) is not less than the above lower limit, the dispersion of the aqueous emulsion copolymer has excellent mechanical stability and cohesive strength. Therefore, the tack and water resistance can be maintained well, so that it is preferable to select and use them appropriately in the above range. If necessary, the suitable range can be selected experimentally in advance within the above range, if necessary, in consideration of the balance between tack and cohesion, the stability over time of adhesive strength, and the like.

Further, in an acrylic monomer mixture comprising a total of 100% by weight of the monomer compositions (a) to (c), a monomer copolymerizable with the monomer (a) and the monomer (b) The comonomer (c) other than the monomer (a) and the monomer (b) is, for example, an acrylate represented by the formula CH ₂ CHCH—COOR ² , R ² represents a C _{1 to} C ₄ linear or branched alkyl group, and an acrylic ester having a glass transition point (Tg ₂ ) of a homopolymer of more than −20 ° C. can be mentioned. Examples of R ² include a methyl group,
Examples thereof include an isopropyl group and a t-butyl group. Specific examples of the acrylate include methyl acrylate and t-butyl acrylate. Further, as the copolymer (C), for example, the formula CH ₂ ＣC
(CH ₃₎ represented by -COOR ^3, where R ³ may be exemplified methacrylic acid ester such as a linear or branched alkyl group of C ₁ -C _4. Examples of R ³ include a methyl group,
Examples include an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group.

Specific examples of the methacrylate monomer include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, and isobutyl methacrylate. The comonomer (c) is, for example, a maleic acid or fumarate ester represented by the formula R ⁴ OOC—CH ＝ CH—COOR ⁵ , wherein R ⁴ and R ⁵ are each independently C ₁ -C _10, preferably can be mentioned comonomer such a linear or branched alkyl group of C ₁ -C _8. Examples of groups R ⁴ and R ⁵ include a methyl group, an ethyl group,
Examples thereof include an n-butyl group, an n-hexyl group, a 2-ethylhexyl group, and an n-octyl group. Specific examples of such a maleic acid or fumaric acid ester monomer include dimethyl malate, di-n-butyl malate, di-2-ethylhexyl malate, di-n-octyl malate, dimethyl fumarate, and di-maleate. n-butyl fumarate, di-2-ethylhexyl fumarate, di-n-
Octyl fumarate can be exemplified. Further, as a comonomer (c), for example, a saturated fatty acid vinyl ester represented by the formula CH ₂ CHOCHOCOR ^{6 wherein} R ⁶ is H
Or C _{1 to} C ₁₈ , preferably a C _{1 to} C ₁₂ linear or branched alkyl group, and examples of the group R ⁶ include a methyl group,
Examples include an ethyl group, a t-butyl group, a t-octyl group, a t-nonyl group, and a t-decyl group. Specific examples of such a saturated fatty acid vinyl ester monomer include:
Examples thereof include vinyl acetate, vinyl propionate, and vinyl versatate. Furthermore, comonomer (c)
For example, a comonomer selected from styrene and acrylonitrile can be similarly used. In addition, the comonomer (c) is not particularly limited, and various comonomers can be appropriately used as long as the excellent effects of the present invention are not impaired.

The amount of the comonomer (c) used is 0 to 50% by weight, preferably 5 to 35% by weight, based on 100% by weight of the total amount of the monomer mixture.
It is. Since the use of the comonomer (c) can vary depending on the type of the comonomer, the amount of the comonomer cannot be uniquely determined. It is useful to adjust the balance and the like as desired, so that it can be appropriately selected in the above range amount so as to meet such purpose. If the amount of the comonomer (c) exceeds the upper limit of the above range and is too large, the tack becomes too small and it becomes difficult to maintain an appropriate balance between the adhesive force and the tack. When is used, it is better to select and use it appropriately in the above range.

The aqueous dispersion type acrylic pressure-sensitive adhesive composition of the present invention,
For example, the monomer composition (a) as described in detail above
Aqueous dispersion-type acrylic pressure-sensitive adhesive containing an aqueous dispersion of an acrylic copolymer (A) obtained by aqueous emulsion copolymerization of an acrylic monomer mixture comprising a total of 100% by weight of (c). The acrylic copolymer (A)
Must have a glass transition point (Tg) of -30 ° C. or less and a gel content of 40% by weight or more in the copolymer.

When the acrylic copolymer (A) according to the present invention has a glass transition point of higher than -30 ° C and a high temperature, there is a problem that the tack becomes too small and the gel content is less than 40% by weight. If the amount is too small, there is a disadvantage that the cohesive strength becomes insufficient. If the gel content is unnecessarily excessive, the adhesive strength tends to be insufficient, and the anchoring property of the pressure-sensitive adhesive sheet to the sheet substrate (support) may be insufficient. It is preferred to employ a gel content of less than 80% by weight.

In the present invention, the glass transition point (Tg) of the acrylic copolymer (A) is a value measured and determined as follows.

Glass transition point: Approximately 10 mg of an aqueous dispersion of an acrylic copolymer was weighed into a cylindrical cell made of aluminum foil having a thickness of about 0.05 mm and having an inner diameter of about 5 mm and a depth of about 5 mm. The sample dried for 2 hours is used as a measurement sample. SSC-5 manufactured by Seiko Electronic Industry Co., Ltd.
Type 000 Differential Scanning Calorim
eter) at -150 ° C at a heating rate of 10 ° C / min.

The glass transition point (Tg) of the acrylic copolymer (A) is determined, for example, from the types of monomers used for preparing the copolymer and the weight fraction in the monomer mixture.
According to Lawrence E. Nielsen, Translated by Shigeharu Onoki, “Mechanical Properties of Polymers” (1st edition, 9th edition, published by Kagaku Dojin on June 30, 1970), using the following formula. So that before the actual copolymerization takes place,
It is well known in the art that the approximate glass transition point (Tg) of the resulting copolymer can be estimated.

However, in the above formula, Tg: the glass transition point of the acrylic copolymer (A) (°
K), Tg ₁ : glass transition point (° of homopolymer of monomer (1))
K), Tg ₂ : glass transition point of homopolymer of monomer (2) (°
K), Tg _n : glass transition point (° of homopolymer of monomer (n))
K), Wt ₁ : weight fraction of monomer (1), Wt ₂ : weight fraction of monomer (2), Wt _n : weight fraction of monomer (n), respectively.

The glass transition point of the homopolymer of the monomer used here, for example, POLYME edited by J. Brandrup, EHImmergut
The values described in R HANDBOOK, Second Edition III-144 to 155 can be used.

In the present invention, the gel content of the acrylic copolymer (A) is a value obtained by measuring the content of ethyl acetate-insoluble components in the acrylic copolymer by the following method.

Gel content:-(a) Preparation of sample film The thickness of the obtained acrylic copolymer sample film is approximately
An aqueous dispersion of an acrylic copolymer is applied on a release material so as to have a thickness of 100 μm, and dried at room temperature for about 1 hour.
Dry at 0 ° C for 2 minutes to prepare a sample film.

(B) Hot water extraction The material film of (a) was cut into a size of about 5 cm x about 15 cm, wound uniformly on a glass rod of about 1.5 cm diameter measured in advance, weighed, and weighed. W ₁₎ obtain.

The sample film wound around the glass rod is placed in a cylindrical paper for Soxhlet extraction, and hot water extraction is performed at a reflux temperature (about 100 ° C.) for 4 hours using a Soxhlet extractor.
The hot water extract obtained is heated to dryness to obtain a hot water extract weight (W ₁ ).

(C) Ethyl acetate extraction In the same manner as in (b) above, the sample film (W ₂ ) wound around a glass rod is subjected to ethyl acetate extraction at a reflux temperature (about 77 ° C.) for 4 hours using a Soxhlet extractor. The obtained ethyl acetate extract is heated to dryness to obtain an ethyl acetate extract weight (W ₂ ).

(D) Calculation of gel content The gel content is calculated according to the following equation.

In addition, when the aqueous dispersion-type acrylic pressure-sensitive adhesive, in addition to the acrylic copolymer and the surfactant, for example, contains an additive such as a pigment, an inorganic filler, a tackifying resin, For example, the pressure-sensitive adhesive is appropriately diluted with deionized water or the like to reduce the viscosity (for example, about 50 cps. Or less), and then centrifuged to separate these additives. The aqueous dispersion of the acrylic copolymer used for measuring the gel content can be separated and collected.
The reason that such separation is possible is that the specific gravity of the acrylic copolymer of the present invention is extremely close to 1, and is considerably lighter than other additives usually used for pressure-sensitive adhesives.

The aqueous dispersion type acrylic pressure-sensitive adhesive composition of the present invention,
An aqueous emulsion copolymer of an acrylic monomer mixture,
As described above, the acrylic copolymer (A) having a specific glass transition range and a specific gel content range, and the following surfactant (i) per 100 parts by weight of the acrylic copolymer (A) (Ii) (i) a nonionic surfactant having an HLB value of 14 or less, an anionic surfactant [however, excluding a sulfosuccinate anionic surfactant] and / or an HLB value of 14;
A surfactant combined with a nonionic surfactant having a HLB value of 14 or less, wherein the nonionic surfactant has a HLB value of 14 or less in an amount of 60 to 99% by weight; 0 to 3.5 parts by weight of an acid ester-based anionic surfactant In addition, the aqueous dispersion type acrylic pressure-sensitive adhesive composition of the present invention includes all surfactants contained in the composition, that is, for example, Total of monomer compositions (a) to (c)
The polymerization emulsifier used in the aqueous emulsion copolymerization of the acrylic monomer mixture consisting of 100% by weight and the surfactant to be added later as required, as a whole, are (i) of the surfactant (B). ) To (ii) must be satisfied.

Among the above surfactants (B), surfactants usable as the combination surfactant (i) include nonionic surfactants such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether. Polyoxyethylene alkyl ethers such as polyoxyethylene octyl phenol ether;
Polyoxyethylene alkyl phenol ethers such as polyoxyethylene nonylphenol ether; sorbitan monolaurate; sorbitan higher fatty acid esters such as sorbitan monostearate and sorbitan trioleate; and polyoxyethylene sorbitan monolaurate Higher fatty acid esters such as polyoxyethylene sorbitan; polyoxyethylene higher fatty acid esters such as polyoxyethylene monolaurate and polyoxyethylene monostearate; glycerol monooleate, glycerol monostearate and polyglycerol Glycerin higher fatty acid esters such as oleate; polyoxyethylene / polyoxypropylene / block copolymer; Can.

Examples of the anionic surfactants include higher fatty acid salts such as sodium oleate; alkyl aryl sulfonates such as sodium dodecylbenzenesulfonate; alkyl sulfate esters such as sodium lauryl sulfate; For example, polyoxyethylene alkyl ether sulfates such as polyoxyethylene lauryl ether sodium sulfate; polyoxyethylene alkyl aryl ether sulfates such as polyoxyethylene nonyl phenol ether sodium sulfate; Can be.

It is necessary that the content of the combined surfactant (B) and (i) is 1 to 4 parts by weight based on 100 parts by weight of the acrylic copolymer (A). If the content is less than 1 part by weight, the mechanical stability of the aqueous dispersion-type acrylic pressure-sensitive adhesive composition tends to be insufficient, and it can be used in the production of the acrylic copolymer (A). Production becomes difficult because the amount of polymerization emulsifier is reduced. If the content exceeds 4 parts by weight, the cohesive force tends to decrease, and
This is not preferable because the adhesive strength is greatly reduced with time and the water-resistant adhesive strength tends to decrease. In addition, among commercially available surfactants,
Some contain volatile solvents such as water and alcohols. In such a case, the amount of the surfactant (B) in the present invention is determined by drying at about 100 ° C. for 60 minutes in a hot air drier. It refers to the amount after removing the volatile solvent.

HL in the combined surfactant of (B) (i) above
Amount of nonionic surfactant with B value of 14 or less (hereinafter, low HLB
The activity occupation value may be abbreviated as 60 to 99% by weight. When the low HLB activator occupancy value is less than 60% by weight, the adhesive strength and cohesive strength tend to decrease,
It is not preferable because the adhesive strength tends to decrease with time, and if it exceeds 99% by weight, the obtained aqueous dispersion type acrylic pressure-sensitive adhesive composition tends to have insufficient mechanical stability. In order to obtain the acrylic copolymer (A) using the combination surfactant (i) as the emulsifier for polymerization, the generation of coarse particles and the coagulation of the reaction system during the emulsion copolymerization process. It is easy to happen and is not preferred.

The HLB value of the low HLB activator of the above (B) (i) is 14 or less, for example, 5 to 14, and the HLB value is 8 from the viewpoint of excellent adhesive strength, cohesive strength and the like of the obtained pressure-sensitive adhesive layer. More preferably, it is from 13 to 13. Examples of the anionic surfactant and the nonionic surfactant having an HLB of more than 14 in combination with the low HLB activator (B) (i) include those of the resulting aqueous dispersion type acrylic pressure-sensitive adhesive composition. The combination is selected from the viewpoints of excellent mechanical stability and ease of production when producing the acrylic copolymer (A) using the combination surfactant (B) (i) as an emulsifier for polymerization. Is good. Among such surfactants, nonionic surfactants include:
Nonionic surfactants of HLB 16 or more, especially nonionic surfactants such as polyoxyalkylene alkyl ethers of HLB 16 or more, and polyoxyalkylene alkyl phenol ethers are preferable, and anionic surfactants include Anionic surfactants such as oxyalkylene alkyl ether sulfates and polyoxyalkylene alkyl aryl ether sulfates are preferred. One or more selected from these surfactants can be used.

In the present invention, the HLB value of the nonionic surfactant is as follows: "Handbook-Cosmetic / formulation raw material-"
[Nikko Chemical Co., Ltd. issued February 1, 1977 854-855
Page]].

HLB value:-Sorbitan monostearate (NIKKO
L, SS-10) and polyoxyethylene sorbitan monostearate (NIKKOL, TS-10), first emulsify the liquid paraffin with the above two emulsifiers, find the optimal emulsifier ratio, HLB value (HLB value that can be emulsified)
Ask for. The calculation formula is as follows.

Usually, the required HLB value of liquid paraffin is 10.1 to 10.3.

Next, the HLB value of the unknown surfactant is measured using a liquid paraffin with a known HLB value. If the unknown activator is hydrophilic, combine it with SS-10.If it is lipophilic, combine it with TS-10 to emulsify the liquid paraffin, find the optimal ratio of stability, and find the HLB of the unknown surfactant. The value is calculated as X with the above formula.

Further, as a method for separating the surfactant and the protective colloid in the aqueous dispersion type acrylic pressure-sensitive adhesive, for example, from the aqueous dispersion of the acrylic copolymer obtained according to the method such as centrifugation described above, A method of coagulating and separating an acrylic copolymer by salting out or the like to obtain an aqueous solution containing a surfactant and a protective colloid may be mentioned. From the aqueous solution, a surfactant and a protective colloid are separated for each type by a method such as liquid chromatography, and can be identified by an infrared spectrophotometer or the like.

Suitable production methods for the aqueous dispersion of the acrylic copolymer used in the present invention include, for example, the above (a) to (c)
The acrylic monomer mixture is preferably emulsion-copolymerized in an aqueous medium in the presence of a water-soluble protective colloid such as PVA using the above-mentioned surfactant as a polymerization emulsifier.

The nonionic and / or anionic surfactant used as a polymerization emulsifier in some cases, and the post-addition surfactant added later as required, are combined with the surfactant (B) (i). It is necessary to use within a range not departing from the requirements of (ii). For example, the surfactants (B) (i) to (i) together with the partially saponified PVA or the modified PVA
A small amount of an anionic surfactant and / or a nonionic surfactant having an HLB value of more than 14 as specified in i) is used as the emulsifier for polymerization, and the above monomer compositions (a) to (c) are used.
Aqueous emulsion copolymerization of a monomer mixture comprising a total of 100% by weight of the nonionic surfactant having an HLB value of 14 or less so as to satisfy the requirements (B) (i) to (ii). Agent, H
It is also possible to post-add a nonionic surfactant and / or an anionic surfactant having an LB value of more than 14. However, the aqueous emulsion copolymerization satisfies the above condition (B) (i) from the viewpoints of easy production of the acrylic copolymer and excellent adhesion and cohesion of the resulting composition. It is particularly preferred to use a combined surfactant as the emulsifier for polymerization.

Examples of the water-soluble protective colloid suitably used for producing the aqueous dispersion of the acrylic copolymer used in the present invention include, for example, polyvinyl alcohol such as partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, and modified polyvinyl alcohol [ Hereinafter, it may be abbreviated as PVA]; cellulose derivatives such as hydroxyethylcellulose, hydroxypropylcellulose and carboxymethylcellulose salts; and natural polysaccharides such as guar gum; and these may be used alone or in combination of two or more. But it can be used. Among these water-soluble protective colloids, viewpoints such as ease of production of an emulsion copolymer, and excellent cohesive strength of a pressure-sensitive adhesive layer formed from the obtained aqueous dispersion type acrylic pressure-sensitive adhesive composition. More preferably, PVAs are used, and it is particularly preferable to use partially saponified PVA having an average degree of polymerization of 500 or less.

The water-soluble protective colloid is preferably used in an amount of 0.1 to 2 parts by weight based on 100 parts by weight of the acrylic copolymer (A). When the amount is less than 0.1 part by weight, the effect of improving the cohesive strength is hardly exhibited, and when it exceeds 2 parts by weight, abnormal thickening and coagulation of the reaction system may occur in the course of emulsion copolymerization. It is better to use in the range of parts.

The above "in an aqueous medium" means in water or an aqueous solution of a water-soluble organic solvent. Examples of such a water-soluble organic solvent include water-soluble alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; water-soluble ketones such as acetone; methyl cellosolve, cellosolve;
Water-soluble ethers such as butyl cellosolve, carbitol and butyl carbitol; and the like. These can be used alone or in combination of two or more,
The used amount is 0 to 0 as the aqueous solution concentration of the water-soluble organic solvent.
About 50% by weight can be exemplified. From the standpoint of storage stability and mechanical stability of the aqueous dispersion type acrylic pressure-sensitive adhesive composition, it is preferable to carry out emulsion copolymerization in water substantially free of these organic solvents.

Further, in the emulsion copolymerization, for example, persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate; and organic peroxides such as tertiary butyl hydroperoxide, cumene hydroperoxide and paramenthane hydroperoxide. And a polymerization initiator such as hydrogen peroxide. These can be used either in one kind or in a combination of plural kinds. The amount used can be appropriately selected, but is, for example, about 0.05 to about 2% by weight, more preferably about 0.1 to about 1.5% by weight, particularly preferably about 0.1 to about 1.5% by weight, based on 100 parts by weight of the obtained acrylic copolymer (A). Amounts such as about 0.2 to about 1.2% by weight can be exemplified.

In the aqueous emulsion copolymerization, a reducing agent can be used in combination, if desired. Examples thereof include reducing organic compounds of ascorbic acid, tartaric acid, citric acid, glucose, formaldehyde sulfoxylate metal salt sugar; reducing inorganic compounds such as sodium thiosulfate, sodium sulfite, sodium bisulfite, and sodium metabisulfite. Can be illustrated. The amount used can be appropriately selected, and for example, an amount of about 0.05 to about 2% by weight based on 100 parts by weight of the acrylic copolymer used can be exemplified.

Furthermore, in the aqueous emulsion copolymerization, a chain transfer agent can be used if desired. Examples of such a chain transfer agent include n-dodecyl mercaptan, t-dodecyl mercaptan, n-butyl mercaptan, and 2-chain mercaptan. Ethylhexyl thioglycolate, 2-mercaptoethanol,
Trichlorobromomethane and the like can be mentioned. An example of the amount used is 0.001 to 0.1 part by weight based on 10 parts by weight of the acrylic copolymer.

The aqueous emulsion copolymerization temperature can be, for example, a temperature of about 20 to 100 ° C., but it is easy to obtain the above-described specific particle size distribution of the acrylic copolymer in the aqueous dispersion. The temperature is preferably about 40 to 90 ° C, more preferably about 60 to 90 ° C.

For example, the pH of the aqueous dispersion of an acrylic copolymer obtained as described above can be adjusted with ammonia water or the like, if necessary. Such a dispersion has a solids content of 30 to 70% by weight, preferably 45 to 65% by weight, a viscosity at 50C and 20 RPM of a B-type rotational viscometer at 50 to 3000 cps.
It is good to be about 8.

The method of forming a pressure-sensitive adhesive layer using the aqueous dispersion type acrylic pressure-sensitive adhesive composition of the present invention includes directly applying the pressure-sensitive adhesive composition on a substrate such as paper or plastic film. A direct method of coating and drying can be employed. Further, a transfer coating method, that is, after applying the pressure-sensitive adhesive composition on a release material such as paper or plastic film that has been release-treated with silicone or the like and drying to form a pressure-sensitive adhesive layer, A method in which the base is overlaid on the pressure-sensitive adhesive layer and pressed to transfer the pressure-sensitive adhesive layer onto the base material can also be used. In such a transfer coating method, repelling is likely to occur at the time of coating on the release material.
The (ii) sulfosuccinate-based anionic surfactant can be used. Examples of the (B) (ii) sulfosuccinate anionic surfactants include alkyl sulfosuccinate esters such as sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, and sodium polyoxyethylene lauryl sulfosuccinate, and derivatives thereof. And the like, and the amount thereof is 3.5 parts by weight or less based on 100 parts by weight of the acrylic copolymer (A). If the amount exceeds 3.5 parts by weight, the cohesive strength, water-resistant adhesive strength and the like tend to decrease, which is not preferable. The amount used is
From the viewpoint of the physical properties of the pressure-sensitive adhesive and the repellency, it is preferable to use 0.1 to 1.5 parts by weight.

The method of using the sulfosuccinate ester-based anionic surfactant of (B) (ii) is generally the same as that of (B)
(Ii) It is usual to dilute the surfactant with water, alcohols or the like, if necessary, and then to post-add it to the aqueous emulsion dispersion of the acrylic copolymer (A). In producing the acrylic copolymer by aqueous emulsion copolymerization, a part or all of the surfactant (B) (ii) may be used in combination as a polymerization emulsifier. In this case, the (B)
(Ii) The ratio of the sulfosuccinate anionic surfactant to the total amount of the emulsifier for polymerization is determined by the easiness of the production of the acrylic copolymer and the excellence of various substances of the obtained pressure-sensitive adhesive layer. From the viewpoint, it is preferably in the range of 0 to 40% by weight.

In the above-mentioned transfer coating method, the composition of the present invention is usually thickened using various thickeners and used. Examples of such a thickener include sodium polyacrylate, the PVAs, the cellulose derivative, an aqueous dispersion-type poly (meth) acrylic acid-based copolymer thickener which thickens with an alkaline property, and the like. it can. The amount of these thickeners can be appropriately determined according to the desired viscosity, and the acrylic copolymer 10
It is in the range of 0 to 10 parts by weight, preferably 0 to 5 parts by weight, as solids with respect to 0 parts by weight.

Further, when the pressure-sensitive adhesive composition of the present invention is used particularly for a polyolefin-based adherend such as polyethylene or polypropylene, coumarone, an indene resin, a terpene / phenol resin, a pt-butylphenol / acetylene resin, Add phenol-formaldehyde resin, terpene resin, xylene-formaldehyde resin, petroleum hydrocarbon resin, hydrogenated hydrocarbon resin, rosin derivative, tackifying resin such as turpentine resin, ethylene-vinyl acetate copolymer resin, etc. By doing so, the pressure-sensitive adhesive can be modified and used. The amount of the tackifying resin to be added can be appropriately selected from the viewpoint of the balance between the adhesive force and the cohesive force to the polyolefin-based adherend. For example, 0 to 60 parts by weight based on 100 parts by weight of the acrylic copolymer Parts, and more preferably 0 to 30 parts by weight.

In the pressure-sensitive adhesive of the present invention, other pigments as necessary,
Inorganic fillers, stabilizers, defoamers, preservatives and antiseptics can be added.

The aqueous dispersion-type acrylic pressure-sensitive adhesive of the present invention generally has a solid content of 30 to 70% by weight, and is measured by a B-type rotational viscometer.
The viscosity at 20 ° C. and 20 RPM is 100 to 1500 cps. And the pH is 3 to 8.5, and when used in the transfer coating method, the solid content is 30 to 70% by weight, at 20 ° C. and 20 RPM by a B-type rotational viscometer. A viscosity of 3000-15000 cps. And a pH of 4-8.5 are preferred.

Hereinafter, the present invention will be described in more detail with reference to Examples along with Comparative Examples.

In addition, preparation of test pieces and adhesion, tack, cohesion,
The water resistance adhesion test and the time-dependent change test of the pressure-sensitive adhesive property were performed by the following methods.

(1) Preparation of test pieces (1-1) Method 1. Aqueous dispersion type acrylic pressure-sensitive adhesive composition on 90 μm-thick kiosto-coated paper (“Mirror Coat” paper (trademark) manufactured by Paperzaki Paper Co., Ltd.) A sample of the product is applied so that the dried pressure-sensitive adhesive layer becomes 25 ± 3 g / m ² , and dried in a hot-air circulating drier at 100 ° C. for 90 seconds to prepare a pressure-sensitive adhesive sheet.

(1-2) Method 2. A pressure-sensitive adhesive sheet is prepared in the same manner as in the above method 1, except that the drying conditions are 130 ° C. and 120 seconds.

(1-3) Method 3. A sample of the aqueous dispersion type acrylic pressure-sensitive adhesive composition was applied on the release agent so that the dried pressure-sensitive adhesive layer was 25 ± 3 g / m ² , and 100 After drying in a hot air circulating dryer at 90 ° C. for 90 seconds, it is transferred to a 90 μm thick cast-coated paper as described in (1-1) above to form a pressure-sensitive adhesive sheet.

(2) Adhesive strength test Brushed with # 280 water-resistant abrasive paper specified in JIS R-6253
SUS304 stainless steel plate and polyethylene plate JIS K-6
Γ ₀ = 43 dyn / cm according to the method specified in 768), and the test piece prepared in (1) was compression-bonded according to the method of JIS Z-238. The peel strength (g / 25 mm) is measured under the condition of min.

(3) Tack test According to the J.DOW method, a 10 cm long test piece was stuck on a slope with a slope angle of 30 °, and a steel ball with a diameter of x / 32 inches was rolled from a position 10 cm above the slope, It is indicated by the size x of the largest diameter ball that stops on the sample.

(4) Cohesion test Scored with # 280 water-resistant research paper specified in JIS R-6253
Specimen adhesion area of 25 × 25 on SUS304 stainless steel plate
A roller with a sticking value of 2 kg was reciprocated one time so as to obtain mm ² .

A 1 kg static load is applied to the sample in an atmosphere of 40 ° C. × 65% RH, and the time until the load drops is measured.

(5) Temporal change test of pressure-sensitive adhesive properties (5-1) After leaving at 20 ° C. and 65% RH for 14 days,
According to (4), the adhesive strength, tack and cohesive strength are measured, and the physical property retention is calculated by assuming that the adhesive strength before standing, tack and cohesive strength are each 100%.

(5-2) After leaving in an atmosphere of 65 ° C. and 80% RH for 5 days,
In the same manner as in (5-1), the respective physical property retention rates of the adhesive force, tack and cohesive force are calculated.

(6) Water resistance test The test piece is pressure-bonded to the same polyethylene plate as before (2) according to the method of JIS Z-238 so that the adhesive area of the test piece becomes 25 × 25 mm ² , and immersed in water at 25 ° C. The time required for the test piece to peel off and rise is measured.

Example 1 70 parts by weight of ion-exchanged water was charged into a reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube and a reflux condenser, and the internal temperature was raised to 80%.
Raise the temperature to ° C. Meanwhile, in another container, 30 parts by weight of ion-exchanged water and Nonion NS-206 [manufactured by NOF Corporation; polyoxyethylene alkyl phenol ether (hereinafter APE)
Nonionic surfactant, HLB
1.6) by weight of Trax H-45 [manufactured by NOF Corporation; polyoxyethylene alkyl phenol ether sulfate soda salt (hereinafter sometimes abbreviated as APES) type anionic surfactant; 27% by weight]
And 1.5 parts by weight of Gohsenol GL-03 [manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; partially saponified PVA, degree of polymerization: 300], 0.2 part by weight, and stirred to dissolve. , 2EHA), 72.1 parts by weight of vinyl acetate (hereinafter may be abbreviated as VAc), and 22.1 parts by weight of acrylic acid (hereinafter may be abbreviated as AA). The monomer mixture is added and stirred to obtain a monomer premix. The contents of the reactor were heated while stirring under a nitrogen stream, and when the contents temperature reached 80 ° C., 0.05 parts each of ammonium persulfate and sodium metabisulfite were added as a polymerization initiator and a reducing agent, and then The polymerization is started by sequentially adding the monomer premix and the polymerization initiator, and the polymerization reaction is carried out for about 3 hours. After the completion of the polymerization reaction, stirring was continued at the same temperature for about 1 hour, followed by cooling, and addition of 0.3 part by weight of aqueous ammonia to adjust the pH to obtain an aqueous dispersion of an acrylic copolymer. This dispersion had a solid content of 50.2% by weight, a pH of 5.6 and a viscosity of 130 cps.
° C, 20 rpm.). Next, an alkali thickener and an aqueous ammonia solution were added to the dispersion, and the mixture was added to about 10,000 cps (2
An aqueous dispersion type acrylic pressure-sensitive adhesive composition having a viscosity of 0 ° C., 20 rpm) was obtained.

Using the obtained adhesive composition, the above (1-1) Method 1
And (1-2) a pressure-sensitive adhesive sheet of a test piece was prepared according to the method 2, and the physical properties of the pressure-sensitive adhesive layer were measured according to the following test methods (2) to (6). Monomer composition of acrylic copolymer Emulsifier composition for polymerization, post-addition surfactant composition, other additives, properties of aqueous emulsion dispersion, copolymer physical properties and physical properties as pressure-sensitive adhesive layer are first The results are shown in Table 2 and Table 2.

Examples 2 and 4 to 7 In Example 1, instead of 22.1 parts by weight of VAc, 28 parts by weight of methyl acrylate (hereinafter sometimes abbreviated as MA) and methyl methacrylate (hereinafter sometimes abbreviated as MMA) were used. 14.5 parts by weight, acrylonitrile (hereinafter sometimes abbreviated as AN) 14.6 parts by weight, styrene (hereinafter sometimes abbreviated as st) 14.4 parts by weight, and dibutyl malate (hereinafter sometimes abbreviated as DBM) Using 33 parts by weight, A
Methacrylic acid (hereinafter sometimes abbreviated as MAA) and itaconic acid (hereinafter sometimes abbreviated as IA) in place of A
And an aqueous dispersion type acrylic pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that an aqueous dispersion of an acrylic copolymer was prepared by changing the amount of 2EHA to be used. Physical properties of the agent layer were measured. Various compositions of the above composition,
The physical properties and physical properties of the pressure-sensitive adhesive layer are shown in Tables 1 and 2.

Examples 3 and 8 In Example 1, instead of 77.4 parts by weight of 2EHA / 22.1 parts by weight of VAc, 76 parts by weight of butyl acrylate (hereinafter, sometimes abbreviated as BA) / ethylene acrylate (hereinafter, EA) were used, respectively. 23.5 parts by weight and BA82
Aqueous dispersion-type acrylic pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that an aqueous dispersion of an acrylic copolymer was prepared by using 17.4 parts by weight of VAc / VAc. Physical properties of the agent layer were measured. Various compositions, physical properties and physical properties of the pressure-sensitive adhesive layer of the above composition are shown in Tables 1 and 2.

Examples 9 and 10 Instead of 22.1 parts by weight of VAc / 0.5 parts by weight of AA in Example 1, VAc / AA was changed to 22.3 parts by weight / 0.3 parts by weight and 21.6 parts by weight / 1 part by weight, respectively. An aqueous dispersion type acrylic pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that an aqueous dispersion of the polymer was prepared, and physical properties of the pressure-sensitive adhesive layer were measured. Various compositions, physical properties and physical properties of the pressure-sensitive adhesive layer of the above composition are shown in Tables 1 and 2.

Examples 11 to 14 and Comparative Examples 1 to 4 In Example 1, nonionic NS- was used as a polymerization emulsifier.
In place of using 1.6 / 1.5 parts by weight of 206 / TRAX H-45 (composition ratio of non-volatile components: 8/2), the aqueous dispersion of the acrylic copolymer was changed by changing the use amount or the composition ratio. An aqueous dispersion-type acrylic pressure-sensitive adhesive composition was obtained in the same manner except for the preparation, and the physical properties of the pressure-sensitive adhesive layer were measured.
Various compositions, physical properties and physical properties of the pressure-sensitive adhesive layer of the above composition are shown in Tables 1 and 2. In Comparative Examples 1 and 4, coagulation of the reaction system occurred during the emulsion polymerization reaction, and an aqueous emulsion dispersion could not be obtained.

Examples 15 to 18 In Example 1, nonionic NS- was used as an emulsifier for polymerization.
Nonionic HS-2045 [manufactured by NOF Corporation; APE instead of 206]
Type) Nonionic surfactant, HLB about 10], Nonionic NS-2
08 [Nippon Yushi Co., Ltd .; APE type nonionic surfactant, HL
B about 12], Nonion NS-210 [manufactured by NOF Corporation; APE type nonionic surfactant, HLB about 13] and Unigri GO-106
Except for preparing an aqueous dispersion of an acrylic copolymer using a polyglycerol fatty acid ester (hereinafter may be abbreviated as PGE) type nonionic surfactant, HLB of about 9 [manufactured by NOF Corporation]. In the same manner, an aqueous dispersion type acrylic pressure-sensitive adhesive composition was obtained, and physical properties of the pressure-sensitive adhesive layer were measured. Tables 1 and 2 show various composition properties of the above composition and physical properties of the pressure-sensitive adhesive layer.

Example 19 and Comparative Examples 5 and 6 In Example 1, nonionic NS- was used as a polymerization emulsifier.
Instead of using 1.6 / 0.4 parts by weight of 206 / TRAX H-45, Nonion NS-206 / Nonion NS-230 [manufactured by NOF Corporation; APE type nonionic surfactant, HLB about 17] and Neugen ET -80 [manufactured by Daiichi Kogyo Seiyaku Co., Ltd .; polyoxyethylene alkyl ether (hereinafter sometimes abbreviated as AE) type nonionic surfactant, HLB approx. 8 / highenol 18
1.6 parts by weight / 0.4 parts by weight of polyoxyethylene alkyl ether sulfate (hereinafter sometimes abbreviated as AES) type anionic surfactant [manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] Aqueous dispersion type acrylic pressure-sensitive adhesive composition was obtained in the same manner except that an aqueous dispersion of an acrylic copolymer was prepared using / 1 part by weight and 1 part by weight / 2 parts by weight, and a pressure-sensitive adhesive layer was obtained. Physical properties were measured. Various compositions, physical properties and physical properties of the pressure-sensitive adhesive layer of the above composition are shown in Tables 1 and 2.

Example 20 An aqueous dispersion type acrylic pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that an aqueous dispersion of an acrylic copolymer was prepared without using Beesenol G-03. The physical properties of the pressure-sensitive adhesive layer were measured. Various compositions, physical properties and physical properties of the pressure-sensitive adhesive layer of the above composition are shown in Tables 1 and 2.

Examples 21 and 22 and Comparative Example 7 Instead of using 85 parts by weight / 14.5 parts by weight of 2EHA / MMA in Example 4, 89.5 parts by weight / 10 parts by weight and 75.
Example 1 except that an aqueous dispersion of an acrylic copolymer was prepared using 2 parts by weight / 24.3 parts by weight and 60 parts by weight / 39.5 parts by weight.
In the same manner as in the above, an aqueous dispersion type acrylic pressure-sensitive adhesive composition was obtained, and physical properties of the pressure-sensitive adhesive layer were measured. Various compositions, physical properties and physical properties of the pressure-sensitive adhesive layer of the above composition are shown in Tables 1 and 2.

Comparative Example 8 An aqueous dispersion-type acrylic resin was prepared in the same manner as in Example 1 except that 0.2 parts by weight of dodecyl mercaptan was added to the monomer premix to prepare an aqueous dispersion of an acrylic copolymer. A pressure-sensitive adhesive composition was obtained, and physical properties of the pressure-sensitive adhesive layer were measured. Various compositions, physical properties and physical properties of the pressure-sensitive adhesive layer of the above composition are shown in Tables 1 and 2.

Example 23 In Example 1, nonionic NS20 was used as an emulsifier for polymerization.
6 An aqueous dispersion of an acrylic copolymer was prepared using only 0.4 parts by weight of Trax H-45 without using 1.6 parts by weight, and then 1.6 parts by weight of Nonion NS-206 were added together with an alkali thickener and an aqueous ammonia solution. Thus, an aqueous dispersion type acrylic pressure-sensitive adhesive composition was obtained, and the physical properties of the pressure-sensitive adhesive layer were measured in the same manner as in Example 1. Various compositions, physical properties and physical properties of the pressure-sensitive adhesive layer of the above composition are shown in Tables 1 and 2.

Example 24 Rapisol B-80 [manufactured by NOF CORPORATION; dioctyl) having a solid content of 40% by weight as well as an alkali thickener and aqueous ammonia was added to the aqueous dispersion of the acrylic copolymer obtained in Example 1. Sodium sulfosuccinate (hereinafter referred to as “sulfosuccinic acid salt”)
Abbreviated as DASS) type anionic surfactant 0.
6 parts by weight were added to obtain an aqueous dispersion type acrylic pressure-sensitive adhesive composition, which was then used to prepare a test piece pressure-sensitive adhesive according to Method (1-2) and Method (1-3). A sheet was prepared, and the physical properties of the pressure-sensitive adhesive layer were measured in the same manner as in Example 1. Various compositions, physical properties and physical properties of the pressure-sensitive adhesive layer of the above composition are shown in Tables 1 and 2.

Claims (5)

(57) [Claims] 1. An aqueous emulsion copolymer of an acrylic monomer mixture (A) having a glass transition point of -30.degree. C. or less and a gel content in the copolymer of 40% by weight or more. (B) the following surfactants (i) and (ii) per 100 parts by weight of the acrylic copolymer (A), a nonionic surfactant having an HLB value of 14 or less, and an anion Surfactants (excluding sulfosuccinate anionic surfactants) and / or HLB value of 14
A surfactant having a HLB value of 14 or less, wherein the nonionic surfactant having a HLB value of 14 or less accounts for 60 to 99% by weight.
An aqueous dispersion-type acrylic pressure-sensitive adhesive composition comprising 4 parts by weight and (ii) 0 to 3.5 parts by weight of a sulfosuccinate ester-based anionic surfactant. 2. The acrylic monomer mixture has the following monomer composition (a) to (c) (a) Formula CH ₂ CHCH—COOR ¹ [wherein R ¹ is a C ₂ -C ₁₀ Represents a linear or branched alkyl group];
Α of the homopolymer acrylic acid ester monomer glass transition point of -20 ° C. or less of 50 to 99.9 wt% (b) C ₃ ~C _5, β- unsaturated mono- - or di - carboxylic acid monomer 0.1-5% by weight and (c) a comonomer other than the (b) monomer and the (b) monomer, which is copolymerizable with the above (a) monomer and (b) monomer 2. The aqueous dispersion type acrylic pressure-sensitive adhesive composition according to claim 1, which is a monomer mixture comprising a total of 100% by weight of 0 to 50% by weight. 3. The above-mentioned (c) comonomer is represented by the formula CH ₂ CHCH—COOR ² wherein R ² represents a C ₁ -C ₄ linear alkyl group. Acrylate having a glass transition point (Tg ₂ ) of a homopolymer exceeding −20 ° C .; Formula CH ₂ ＣC (CH ₃ ) —COOR ³ [wherein, R ³ is a C _{1 to} C ₄ linear group. A methacrylic acid ester represented by the following formula: R ⁴ OOC—CH ＝ CH—COOR ⁵ wherein R ⁴ and R ⁵ are each independently a C _{1 to} C ₁₀ linear or Maleic acid or fumaric acid ester represented by the following formula: CH ₂ = CHOCOR ⁶ [wherein R ⁶ represents a C ₁ -C ₁₈ linear or branched alkyl group] At least one comonomer selected from the group consisting of a saturated fatty acid vinyl ester represented by the following formula: styrene; and acrylonitrile. Aqueous dispersion-type acrylic pressure-sensitive adhesive composition of the second term describes the scope of the allowed claims. 4. The method according to claim 1, wherein the acrylic copolymer is (B)
The combination surfactant (i) is used as an emulsifier for polymerization, and is obtained by subjecting the acrylic monomer mixture to aqueous emulsion copolymerization. Item 4. The aqueous dispersion type acrylic pressure-sensitive adhesive composition according to any one of the above items 3. 5. The acrylic copolymer is obtained by aqueous emulsion copolymerization in the presence of 0.1 to 2 parts by weight of a water-soluble protective colloid per 100 parts by weight of the acrylic copolymer. The aqueous dispersion-type acrylic pressure-sensitive adhesive composition according to any one of claims 1 to 4, characterized in that: