JP2006077084A - Water dispersion type adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water dispersion type adhesive that has excellent adhesion performance of the high retention power at elevated temperature and consistently both of the high adhesion to nonpolar adherends and the high repulsion properties on the curved face. <P>SOLUTION: Particles (a) comprising a polymer obtained by polymerizing a vinyl monomer or a copolymer obtained by copolymerizing this monomer with other monomers that are copolymerizable with the same are dispersed in water to provide the water dispersion type adhesive in which the particles have each fine convex parts (b). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an adhesive composition in various adhesive processed products such as a tape, a label, a sheet or a double-sided tape, and an adhesive processed product using the same, and more specifically, high holding power and nonpolarity at high temperatures. The present invention relates to a water-dispersed pressure-sensitive adhesive composition excellent in high adhesive strength and phase resilience to an adherend.

  In recent years, in the field of pressure-sensitive adhesives, solvent-based pressure-sensitive adhesives, which have been the main body, are being replaced by water-dispersed pressure-sensitive adhesives due to demands for solvent-free from the viewpoints of pollution control, safety and health, and resource saving. However, water-dispersed pressure-sensitive adhesives have not yet reached the solvent-type level in terms of pressure-sensitive adhesive performance, and solvent-based pressure-sensitive adhesives are used as usual for applications that require high-level pressure-sensitive adhesive performance. At present, further improvement of the agent is eagerly desired. One of the major drawbacks of water-dispersed adhesives is that it is very difficult to balance the physical properties of the adhesive. In other words, when trying to improve curved surface adhesion, which is a practically important adhesive performance, it is generally necessary to sacrifice cohesive strength (holding power), especially holding power at high temperatures, or tack, and adhesive performance. Is difficult to maintain at a high level and in good balance.

Conventionally, improvement studies have been made mainly on water-dispersed acrylic pressure-sensitive adhesives for the above problems, but no effective means have been found so far. For example, JP-A-63-234076 discloses a composition in which particles having a specific average particle diameter are mixed in a specific ratio in an aqueous dispersion type acrylic pressure-sensitive adhesive. However, according to the knowledge of the present inventors, it is not sufficient to balance the adhesive properties at a high level only by mixing particles having a particle size distribution of two peaks in the same composition copolymer as described above. is there.
JP-A-63-234076

The present invention overcomes the drawbacks of the conventional water-dispersed pressure-sensitive adhesives as described above, and has water-adhesive performance that achieves both high holding power at high temperatures, high adhesion to non-polar adherends, and phase resilience. The object is to provide a dispersion-type pressure-sensitive adhesive composition.

  In order to solve these problems, the present inventors have conducted extensive research focusing on the fact that the particle form in the water-dispersed type has an extremely large effect on the adhesion performance, and as a result, the vinyl monomer or the single amount thereof. A water-dispersed pressure-sensitive adhesive having convex portions on the surface of particles (a) composed of (co) polymers with other monomers copolymerizable with the body has high holding power at high temperatures and nonpolar adhesion It has been found that both high adhesion to the body and phase rebound are achieved, and the present invention has been completed.

That is, the present invention
It consists of an aqueous dispersion of particles (a) consisting of a vinyl monomer or a (co) polymer of other monomers copolymerizable with these monomers, and a convex portion ( It is a water dispersion type adhesive which has b).

The water-dispersed pressure-sensitive adhesive of the present invention can provide a pressure-sensitive adhesive product that achieves both high holding power at high temperatures, high adhesion to non-polar adherends, and phase resilience.

  Hereinafter, the present invention will be described in more detail.

  Specific examples of the vinyl monomer constituting the particles (a) in the present invention include, for example, methyl-, ethyl-, n-propyl-, isopropyl-, n-butyl-, isobutyl-, sec-butyl-, tert-butyl-, n-amyl-, isoamyl-, n-hexyl-, cyclohexyl-, heptyl-, octyl-, 2-ethylhexyl-, 2-ethyloctyl-, decyl-, dodecyl-, octadecyl-, lauryl-, Monomers containing acrylic acid ester or methacrylic acid ester such as stearyl- and the like can be mentioned, and these can be used alone or in admixture of two or more, but preferably the alkyl group has 1 to 10 carbon atoms. More preferably, two or more kinds of (meth) acrylic acid alkyl ester monomers having 1 to 8 carbon atoms in the alkyl group are used. Mixed and used in. When the carbon number of the alkyl group becomes too long, the polymerization reaction tends not to proceed smoothly.

  In addition to these vinyl monomers, other monomers copolymerizable therewith can also be used. Specifically, examples of the monomer containing a hydroxyl group include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 2 -Hydroxy vinyl ether, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monoacrylate, polypropylene glycol monomethacrylate, monomers containing carboxyl groups such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid , Fumaric acid, citraconic acid, monomers containing glycidyl group such as glycidyl acrylate, glycidyl meta Relate, glycidyl cinnamate, allyl glycidyl ether, vinylcyclohexene monoepoxide, monomers containing amide groups such as acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-methylol acrylamide, sulfonic acid groups Examples of the monomer containing styrene sulfonic acid and its salts, 2-acrylamido-2-methylpropane sulfonic acid and its salts, allyl sulfonic acid and its salts, methallyl sulfonic acid and its salts, etc. Can be used alone or in admixture of two or more.

  Further, as other monomers, in addition to the above vinyl monomers, monomers having two or more ethylenically unsaturated double bonds and other monoethylenically unsaturated monomers as necessary Etc. may be copolymerized.

  First, specific examples of the monomer having two or more ethylenically unsaturated double bonds include butadiene, divinylbenzene, (poly) ethylene glycol diacrylate, (poly) ethylene glycol dimethacrylate, and trimethylol. Examples thereof include propane triacrylate and trimethylolpropane trimethacrylate, and these can be used alone or in combination of two or more.

  Examples of other monoethylenically unsaturated monomers include vinyl monomers such as vinyl acetate, styrene, α-methylstyrene, divinylbenzene, acrylonitrile, methacrylonitrile, vinyl chloride, and vinylpyrrolidone.

  2 or more types of ethylenically unsaturated monomers each containing a vinyl monomer or other monomer copolymerizable with these monomers, each having a different functional group, if necessary 2 As a method for producing a copolymer of monomers having at least one ethylenically unsaturated double bond and other monoethylenically unsaturated monomers (hereinafter referred to as acrylic monomers), there is no particular limitation. However, it is usually sufficient to carry out according to a known emulsion polymerization method, and no special method is required. That is, it is an emulsion polymerization method comprising water, the above vinyl monomer mixture, a surfactant, a chain transfer agent (polymerization degree adjusting agent), and a radical polymerization initiator as basic components.

  First, specific examples of the surfactant include fatty acid soap, rosin soap, alkyl sulfonate, alkyl benzene sulfonate, dialkyl aryl sulfonate, alkyl sulfosuccinic acid, polyoxyethylene alkyl sulfate, and polyoxyethylene alkyl. Anionic surfactants such as aryl sulfates, nonionic surfactants such as polyoxyethylene alkyl aryl ethers, polyoxyethylene sorbitan fatty acid esters, oxyethylene oxypropylene copolymers, etc., usually anionic surfactants alone or anions Used in a mixed system of a surfactant and a nonionic surfactant. Furthermore, a radically polymerizable surfactant or a cationic surfactant can be used as necessary.

  Specific examples of the chain transfer agent include mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan and mercaptoethanol, and halogenated hydrocarbons such as carbon tetrachloride.

  Moreover, as radical initiators, persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate, peroxides such as hydrogen peroxide, benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, Examples include azobis compounds such as 2-azobisisobutyronitrile, and persulfate is particularly preferable.

  In the emulsion polymerization of the present invention, the polymerization temperature is generally in the range of 60 to 90 ° C., but low temperature redox polymerization in which a reducing agent such as sodium bisulfite, ascorbic acid (salt), Rongalite is combined with a radical polymerization initiator is used. It can also be used. If necessary, a pH regulator such as sodium hydroxide, potassium hydroxide, sodium hydrogen carbonate, sodium carbonate, sodium hydrogen phosphate, or a polymerization regulator such as a PH buffer can be added.

  Moreover, the water-dispersed pressure-sensitive adhesive of the present invention can also improve stability by carrying out alkali neutralization. As the neutralizing agent, for example, an aqueous ammonia solution, a hydroxide such as sodium hydroxide, an amine or the like can be used.

  The volume average particle diameter of the copolymer particles obtained by the emulsion polymerization is usually 30 to 3,000 nm, preferably 200 to 1,000 nm, and more preferably 300 to 700 nm. If it is less than 30 nm, the viscosity increases and the solid content (concentration) cannot be sufficiently increased, and if it exceeds 3000 nm, problems such as sedimentation of particles may occur.

  The organic substance and / or inorganic substance of the convex part (b) used in the present invention is not particularly limited as long as it is a water-insoluble organic substance and / or inorganic substance dispersed in water in a colloidal state. For example, acrylic resin, styrene resin, vinyl acetate resin, vinyl chloride resin, amide resin, polyester resin, polyolefin resin, butadiene resin, rubber resin, fluorine resin, urethane resin, epoxy Resin, tackifying resin, and the like.

  Examples of inorganic substances include calcium carbonate, kaolin, clay, amorphous silica, zinc oxide, aluminum oxide, aluminum hydroxide, satin white, aluminum silicate, alumina, zeolite, sepiolite, smectite, magnesium silicate, magnesium carbonate, water Examples include magnesium oxide, diatomaceous earth, and hydrotalcite.

  Among these, organic particles mainly composed of (meth) acrylic acid ester and styrene are preferable.

  The ratio of the average length of the protrusions (b) to the volume average particle diameter of the particles (a) (average length of the protrusions (b) / volume average particle diameter of the particles (a)) is 0.01 to It is the range of 1.0, Preferably it is the range of 0.05-0.8, More preferably, it is the range of 0.2-0.6. If it is less than 0.01 or exceeds 1.0, it is impossible to achieve both holding force and adhesive force.

  As a method for forming the convex portion (b), the particle (a) is polymerized in the presence of an organic substance and / or an inorganic substance that can become the convex portion (b), or the convex portion (b ) And the like can be used.

  The water-dispersed pressure-sensitive adhesive obtained as described above impairs the effects of the present invention from the types and amounts of compounding agents used in the field of pressure-sensitive adhesives in order to impart the required physical properties and performance. It can be added as needed within a range that does not occur.

Examples of compounding agents that can be added include thickeners, mechanical stability imparting agents, tackifiers, leveling agents, wetting agents, film-forming aids, crosslinking agents, preservatives, rust preventives, pigments, fillers, and dispersions. Agents, antifreeze agents, antifoaming agents, and the like, and these can be used alone or in combination of two or more.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the examples. In addition, the part in an example represents a mass part and% represents the mass%, respectively.

Furthermore, each physical property value was measured by the following method.

i) Solid content (unit:%)
About 2 g of the water-dispersed pressure-sensitive adhesive composition was precisely weighed in a petri dish, dried at 105 ° C. for 3 hours and then weighed again, and the following formula was calculated.

Solid content (%) = (A−B) / A × 100
Here, A is the weight before drying, and B is the weight after drying at 105 ° C. for 3 hours.

ii) Particle size (μm)
Volume average particle diameter measured by dynamic light scattering method using LPA-3100 manufactured by Otsuka Electronics Co., Ltd.

iii) Preparation of pressure-sensitive adhesive sheet After applying to release paper to a dry weight of about 20 g / m ² and drying at 100 ° C. for 3 minutes, it is transferred to fine paper (55K continuous weight) and a sample for measuring the physical properties of pressure-sensitive adhesive It was created.

iv) Adhesive property evaluation method a) Adhesive strength A test piece having a width of 25 mm and a length of 150 mm was used in a 23 kg-50% RH atmosphere with a 2 kg weight rubber roll, and a stainless steel plate having a thickness of 5 mm × width 50 mm × length 125 mm. (SUS) After being pressure-bonded to a polyethylene plate (PE) at a speed of 300 mm / min, after being left in an atmosphere of 23 ° C.-50% RH for 30 minutes, 180 ° peel strength was measured according to JIS Z0237.
b) Cohesive force In accordance with JIS Z0237, a test piece having a width of 25 mm and a length of 150 mm was bonded to a stainless steel plate (SUS304) with a rubber roll having a weight of 2 kg in an atmosphere of 23 ° C.-50% RH so that the adhesion area was 25 mm × 25 mm. 30 minutes after pressure bonding, the bonded sample was hung vertically in an atmosphere of 70 ° C., 1 kg of weight was placed on the lower end of the test piece, and the time until the weight dropped or the displacement width after 1440 minutes Was measured.
c) Ball tack (J-Dow method)
In an atmosphere of 23 ° C.-50% RH, a test piece width of 50 mm and a length of 250 mm were measured in accordance with JIS Z0237. D) Phase rebound A polyethylene cylinder having a diameter of 10 mm was used as an adherend, and a width of 10 mm. A test piece having a length of 20 mm was bonded in a length direction parallel to the circumference in an atmosphere of 23 ° C.-50% RH, and the peel length was measured after 2 days. A peeling length of less than 0.5 mm was indicated by ○, 0.5 mm or more and less than 1 mm by Δ, and 1 mm or more by ×.

Monomers used in Examples and Comparative Examples are represented by the following abbreviations.

2-ethylhexyl acrylate 2EHA
Methyl methacrylate ... MMA
Acrylic acid ... AA
n-dodecyl mercaptan ... nDM
Styrene ... ST
Isobornyl methacrylate ... IBX

[Example 1]
A temperature-adjustable reactor equipped with a nitrogen introduction tube and a stirrer was charged with 262 parts of distilled water, heated to 80 ° C. under a nitrogen stream, and then the monomer consisting of 15 parts of an anionic surfactant (Perex SSL: A monomer emulsion obtained by emulsifying and dispersing 0.15 part of Kao Co., Ltd. in 0.075 part of ammonium persulfate and 7.5 part of distilled water was continuously added dropwise over 30 minutes, and further 60 ° C. at 60 ° C. The reaction was continued for a minute. Next, a monomer mixture consisting of 2EHA 425 parts, MMA 65 parts, AA 10 parts, nDM 0.2 parts is added to an anionic surfactant (Perex SSL: manufactured by Kao Corporation) 5.0 parts, ammonium persulfate 2.5 parts, distilled A monomer emulsion emulsified and dispersed in 250 parts of water was continuously added in 4 hours, and the reaction was further continued at 80 ° C. for 3 hours to complete the polymerization, followed by cooling. The completed emulsion is adjusted to pH 7.5 with aqueous ammonia and then filtered through a wire mesh or the like to obtain an acrylic copolymer emulsion having a solid content of 50.6%. From the micrograph, an acrylic copolymer emulsion having a volume average particle diameter of 420 nm including an average length of the convex portions of 140 nm was obtained.

  Furthermore, 0.1 part of Nopco 8034 (antifoaming agent: manufactured by San Nopco Co., Ltd.) and 1 part of sodium dialkylsulfosuccinate (Neocol SW-C: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) are used for the acrylic copolymer emulsion. In addition, 0.0 part of an associative thickener (Adecanol UH-420: manufactured by Asahi Denka Kogyo Co., Ltd.) was added in an amount such that the viscosity at 60 rpm with a B-type rotational viscometer at 23 ° C. was 3000 mPa · s. A dispersed acrylic pressure-sensitive adhesive was obtained.

[Example 2]
A temperature-adjustable reactor equipped with a nitrogen introduction tube and a stirrer was charged with 262 parts of distilled water and heated to 80 ° C. under a nitrogen stream, and then the monomer consisting of 15 parts of IBX was converted to an anionic surfactant (Perex SSL: A monomer emulsion obtained by emulsifying and dispersing 0.15 part of Kao Co., Ltd. in 0.075 part of ammonium persulfate and 7.5 part of distilled water was continuously added dropwise over 30 minutes, and further 60 ° C. at 60 ° C. The reaction was continued for a minute. Next, a monomer mixture consisting of 2EHA 425 parts, MMA 65 parts, AA 10 parts, nDM 0.2 parts is added to an anionic surfactant (Perex SSL: manufactured by Kao Corporation) 5.0 parts, ammonium persulfate 2.5 parts, distilled A monomer emulsion emulsified and dispersed in 250 parts of water was continuously added in 4 hours, and the reaction was further continued at 80 ° C. for 3 hours to complete the polymerization, followed by cooling. The pH of the completed emulsion is adjusted to 7.5 with aqueous ammonia, and then filtered through a wire mesh or the like to obtain an acrylic copolymer emulsion having a solid content of 50.3%. From the micrograph, an acrylic copolymer emulsion having a volume average particle diameter of 387 nm including an average length of the convex portions of 86 nm was obtained.

  Furthermore, 0.1 part of Nopco 8034 (antifoaming agent: manufactured by San Nopco Co., Ltd.) and 1 part of sodium dialkylsulfosuccinate (Neocol SW-C: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) are used for the acrylic copolymer emulsion. In addition, 0.0 part of an associative thickener (Adecanol UH-420: manufactured by Asahi Denka Kogyo Co., Ltd.) was added in an amount such that the viscosity at 60 rpm with a B-type rotational viscometer at 23 ° C. was 3000 mPa · s. A dispersed acrylic pressure-sensitive adhesive was obtained.

[Example 3]
A temperature-adjustable reactor equipped with a nitrogen introduction tube and a stirrer was charged with 262 parts of distilled water and heated to 80 ° C. under a nitrogen stream, and then the monomer consisting of 15 parts of EA was converted to an anionic surfactant (Plex SSL: A monomer emulsion obtained by emulsifying and dispersing 0.15 part of Kao Co., Ltd. in 0.075 part of ammonium persulfate and 7.5 part of distilled water was continuously added dropwise over 30 minutes, and further 60 ° C. at 60 ° C. The reaction was continued for a minute. Next, a monomer mixture consisting of 2EHA 425 parts, MMA 65 parts, AA 10 parts, nDM 0.2 parts is added to an anionic surfactant (Perex SSL: manufactured by Kao Corporation) 5.0 parts, ammonium persulfate 2.5 parts, distilled A monomer emulsion emulsified and dispersed in 250 parts of water was continuously added in 4 hours, and the reaction was further continued at 80 ° C. for 3 hours to complete the polymerization, followed by cooling. The completed emulsion is adjusted to pH 7.5 with aqueous ammonia and then filtered through a wire mesh or the like to obtain an acrylic copolymer emulsion having a solid content of 50.5%. From the micrograph, an acrylic copolymer emulsion having a volume average particle diameter of 350 nm including an average length of the convex portions of 190 nm was obtained.

  Furthermore, 0.1 part of Nopco 8034 (antifoaming agent: manufactured by San Nopco Co., Ltd.) and 1 part of sodium dialkylsulfosuccinate (Neocol SW-C: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) are used for the acrylic copolymer emulsion. In addition, 0.0 part of an associative thickener (Adecanol UH-420: manufactured by Asahi Denka Kogyo Co., Ltd.) was added in an amount such that the viscosity at 60 rpm with a B-type rotational viscometer at 23 ° C. was 3000 mPa · s. A dispersed acrylic pressure-sensitive adhesive was obtained.

[Example 4]
A temperature-adjustable reactor equipped with a nitrogen introduction tube and a stirrer was charged with 210 parts of distilled water and 75 parts of Snowtex 20L (colloidal silica manufactured by Nissan Chemical Industries, Ltd., particle size 40 nm) and heated to 80 ° C. under a nitrogen stream. After that, a monomer mixture consisting of 425 parts of 2EHA, 65 parts of MMA, 10 parts of AA, and 0.2 parts of nDM was added to 5.0 parts of an anionic surfactant (Perex SSL: manufactured by Kao Corporation), 2.5 parts of ammonium persulfate, A monomer emulsion emulsified and dispersed in 250 parts of distilled water was continuously added in 4 hours, and the reaction was further continued at 80 ° C. for 3 hours to complete the polymerization, followed by cooling. The completed emulsion is adjusted to pH 7.5 with aqueous ammonia and then filtered through a wire mesh or the like to obtain an acrylic copolymer emulsion having a solid content of 50.1%. From the micrograph, an acrylic copolymer emulsion having a volume average particle diameter of 260 nm including an average length of 40 nm of colloidal silica in the convex portion was obtained.

  Furthermore, 0.1 part of Nopco 8034 (antifoaming agent: manufactured by San Nopco Co., Ltd.) and 1 part of sodium dialkylsulfosuccinate (Neocol SW-C: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) are used for the acrylic copolymer emulsion. In addition, 0.0 part of an associative thickener (Adecanol UH-420: manufactured by Asahi Denka Kogyo Co., Ltd.) was added in an amount such that the viscosity at 60 rpm with a B-type rotational viscometer at 23 ° C. was 3000 mPa · s. A dispersed acrylic pressure-sensitive adhesive was obtained.

[Comparative Example 1]
262 parts of distilled water was charged into a temperature-controllable reactor equipped with a nitrogen introduction tube and a stirrer, heated to 80 ° C. under a nitrogen stream, and then a single quantity consisting of 2EHA 440 parts, MMA 65 parts, AA 10 parts, and nDM 0.2 parts. A monomer emulsion obtained by emulsifying and dispersing the body mixture in 5.0 parts of an anionic surfactant (Perex SSL: manufactured by Kao Corporation), 2.5 parts of ammonium persulfate, and 258 parts of distilled water is continuously added in 4 hours. The reaction was further continued at 80 ° C. for 3 hours to complete the polymerization and then cooled. The completed emulsion is adjusted to pH 7.5 with aqueous ammonia and then filtered through a wire mesh or the like to obtain an acrylic copolymer emulsion having a solid content of 50.9%. From the micrograph, an acrylic copolymer emulsion having a volume average particle diameter of 420 nm not including a convex portion was obtained.

  Furthermore, 0.1 part of Nopco 8034 (antifoaming agent: manufactured by San Nopco Co., Ltd.) and 1 part of sodium dialkylsulfosuccinate (Neocol SW-C: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) are used for the acrylic copolymer emulsion. In addition, 0.0 part of an associative thickener (Adecanol UH-420: manufactured by Asahi Denka Kogyo Co., Ltd.) was added in an amount such that the viscosity at 60 rpm with a B-type rotational viscometer at 23 ° C. was 3000 mPa · s. A dispersed acrylic pressure-sensitive adhesive was obtained.

[Comparative Example 2]
After adding 262 parts of distilled water to a temperature-controllable reactor equipped with a nitrogen introduction tube and a stirrer and raising the temperature to 80 ° C. under a nitrogen stream, ST15 part, 2EHA 425 parts, MMA 65 parts, AA 10 parts, nDM 0.2 part A monomer emulsion obtained by emulsifying and dispersing the monomer mixture in 5.0 parts of an anionic surfactant (Perex SSL: manufactured by Kao Corporation), 2.5 parts of ammonium persulfate, and distilled water 258 in 4 hours. The reaction was continuously added, and the reaction was further continued at 80 ° C. for 3 hours to complete the polymerization, followed by cooling. The completed emulsion is adjusted to pH 7.5 with aqueous ammonia and then filtered through a wire mesh or the like to obtain an acrylic copolymer emulsion having a solid content of 50.9%. From the micrograph, an acrylic copolymer emulsion having a volume average particle diameter of 411 nm not including a convex portion was obtained.

  Furthermore, 0.1 part of Nopco 8034 (antifoaming agent: manufactured by San Nopco Co., Ltd.) and 1 part of sodium dialkylsulfosuccinate (Neocol SW-C: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) are used for the acrylic copolymer emulsion. In addition, 0.0 part of an associative thickener (Adecanol UH-420: manufactured by Asahi Denka Kogyo Co., Ltd.) was added in an amount such that the viscosity at 60 rpm with a B-type rotational viscometer at 23 ° C. was 3000 mPa · s. A dispersed acrylic pressure-sensitive adhesive was obtained.

  Table 1 shows the results of evaluating the coating performance of the water-dispersed acrylic pressure-sensitive adhesives obtained in the above Examples and Comparative Examples.

The water-dispersed pressure-sensitive adhesive of the present invention enables the production of pressure-sensitive adhesive labels and pressure-sensitive adhesive tapes that have excellent adhesion to low-polar adherends such as polyolefin, which have reciprocal properties, cohesive strength at high temperatures, and excellent phase resilience. The application can be expanded to fields where conventional water-dispersed pressure-sensitive adhesives cannot be used.

2 is an electron micrograph of the water-dispersed pressure-sensitive adhesive obtained in Example 1. 2 is an electron micrograph of a water-dispersed pressure-sensitive adhesive obtained in Comparative Example 1.

Claims (7)

It consists of an aqueous dispersion of particles (a) consisting of a vinyl monomer or a (co) polymer of other monomers copolymerizable with these monomers, and a convex portion ( A water-dispersed pressure-sensitive adhesive having b).
The water-dispersed pressure-sensitive adhesive according to claim 1, wherein the vinyl monomer is an acrylic acid alkyl ester, a methacrylic acid alkyl ester, or a mixture thereof.
The water-dispersed pressure-sensitive adhesive according to claim 1, wherein the particles (a) have a volume average particle diameter of 30 to 3,000 nm.
The ratio of the average length of the convex portions (b) to the volume average particle size of the particles (a) (average length of the convex portions (b) / volume average particle size of the particles (a)) is 0.01 to The water-dispersed pressure-sensitive adhesive according to claim 1, which is 1.0.
The aqueous dispersion of the particles (a) is obtained by polymerizing a vinyl monomer or another monomer copolymerizable with these monomers in an aqueous medium. Water-dispersed adhesive.
The water-dispersed pressure-sensitive adhesive according to claim 1, wherein the particles (a) have a glass transition temperature of -60 to 110 ° C.
The water-dispersed pressure-sensitive adhesive according to claim 1, wherein the convex part (b) is made of an organic substance and / or an inorganic substance.