JP2005247929A - Water-dispersed pressure-sensitive acrylic adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a water-dispersed pressure-sensitive adhesive composition excellent in coating stability and capable of giving a good coated surface even under high-shear coating conditions encountered at the restart after coating interruption in e.g., paper exchange or during high-speed coating. <P>SOLUTION: This water-dispersed pressure-sensitive acrylic adhesive composition is obtained by using an alkyl (meth)acrylate as the main component and copolymerizing this monomer with at least two ethylenically unsaturated monomers (a) having their respective different functional groups or the at least two ethylenically unsaturated monomers (a) having their respective different functional groups and a monomer (b) having at least two ethylenic unsaturations, and/or other monoethylenically unsaturated monomers (c). A pressure-sensitive processed product using the same and a method for producing the pressure-sensitive processed product are also provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a water-dispersed pressure-sensitive adhesive composition used for pressure-sensitive adhesives in various types of pressure-sensitive processed products such as pressure-sensitive adhesive tapes, labels, sheets or double-sided tapes, and pressure-sensitive adhesive processed products using the same. Water-dispersed pressure-sensitive adhesive composition that can provide a smooth coated surface without streaks even under conditions such as high-speed coating that requires a large share during coating after coating interruption due to splicing, etc. In addition, the present invention relates to an adhesive processed product having excellent productivity and a method for producing the same.

  Since the water-dispersed pressure-sensitive adhesive composition is an organic solvent-free adhesive, the organic solvent does not scatter or disperse in the atmosphere due to drying or the like as compared with the organic solvent-based pressure-sensitive adhesive, so there is less air pollution. In recent years, it has been widely used because of its advantages such as excellent safety and health.

  The water-dispersed pressure-sensitive adhesive composition having such advantages can be applied directly to a substrate such as paper, film, or sheet, or applied to a release material, and then transferred to various substrates so that the adhesive Processed into various adhesive products such as tape, label, sheet or double-sided tape.

  In the above coating process, the coating may be temporarily interrupted when the base material or release material is replaced (at the time of paper splicing) and restarted after the work is completed, but depending on the type of coating machine, the resin may be in the air. There was a problem that the exposed surface was left exposed, causing skinning or the like, and streaks were generated on the coated surface at the time of restart. Furthermore, in the past, it was performed at a relatively low coating speed, but in order to improve the productivity of adhesive processed products and reduce manufacturing costs, the coating speed of the adhesive composition to various substrates Need to be done faster. However, in the case of a water-dispersed pressure-sensitive adhesive, by increasing the coating speed, the drying efficiency is reduced, or the shear stress applied to the pressure-sensitive adhesive is increased, so that agglomerates are easily generated, or the coating agent tank Since problems such as easy generation of bubbles occur in the interior, the coating speed is naturally limited, and it has been difficult to achieve sufficient productivity improvement.

  As a means for solving this problem, there are methods such as increasing the solid content of the water-dispersed pressure-sensitive adhesive to improve the drying efficiency and adding an additive for improving the mechanical stability to suppress the generation of aggregates. However, it has been clarified that not all pressure-sensitive adhesive compositions satisfying these conditions can solve the above problems.

  In JP-A-10-265753, an acrylic emulsion-type pressure-sensitive adhesive composition is a pressure-sensitive adhesive composition having improved mechanical stability by using a C10-22 carboxylic acid ammonium salt (or lower amine salt) in combination. Propose a thing. However, streaks generated when restarting from interruption of coating due to paper splicing or the like is also a problem that cannot be solved by using an additive having high hydrophobicity as described above, since it also relates to resin skinning.

JP-A-8-218047 discloses a water-dispersed acrylic pressure-sensitive adhesive composition having a solid content of 50% by weight or more, an average particle size of polymer particles of 0.2 μm or more, and a shear rate of 1.0 × 10 ^5. A pressure-sensitive adhesive composition suitable for high-speed coating is proposed by setting the viscosity at (1 / s) to 20 mpa · s or more. However, the coating properties of the water-dispersed pressure-sensitive adhesive composition, particularly the occurrence of streaks during coating, is closely related to the mechanical stability of the composition, so it is not sufficient to specify only the solid content, particle size, and viscosity. The mechanical stability of the composition became an important factor.
JP-A-10-265753 JP-A-8-218047

  The present invention can be applied even under coating conditions where it is difficult to obtain a clean and smooth coating surface, such as when restarting after interrupting coating due to paper joining or high-speed coating, which requires a large share during coating. It is intended to provide a water-dispersed pressure-sensitive adhesive composition capable of obtaining a smooth coated surface free of adhesive, an adhesive processed product having excellent productivity using the same, and a method for producing the same.

  As a result of intensive studies to solve these problems, the present inventors have as a main component a (meth) acrylic acid alkyl ester containing at least two types of ethylenically unsaturated monomers having a specific functional group. The water-dispersed pressure-sensitive adhesive composition has a good coating property when the mechanical stability of the resin shows a specific value in a Marlon mechanical stability tester, and after the coating is interrupted due to a paper splicing, etc. It is possible to obtain a smooth coated surface without streaks even under coating conditions where it is difficult to obtain a clean and smooth coated surface, such as high-speed coating, which requires a large share during coating. The headline and the present invention were completed.

That is, the present invention is specified by the following [1] to [7].
[1] Two or more ethylenically unsaturated monomers (a) each having a (meth) acrylic acid alkyl ester as a main component and having different functional groups, or ethylenically unsaturated monomers each having a different functional group The monomer (a) is copolymerized with two or more monomers (b) having at least two ethylenically unsaturated double bonds and / or other monoethylenically unsaturated monomers (c). A water-dispersed acrylic pressure-sensitive adhesive composition obtained.
[2] The ethylenically unsaturated monomers (a) each having a different functional group are an ethylenically unsaturated monomer containing a carboxyl group and an ethylenically unsaturated monomer containing a hydroxyl group [1] The water-dispersed acrylic pressure-sensitive adhesive composition as described.
[3] A water-dispersed acrylic pressure-sensitive adhesive composition obtained by mixing a water-dispersible acrylic pressure-sensitive adhesive emulsion with the water-dispersed acrylic pressure-sensitive adhesive composition according to [1] or [2].
[4] The water-dispersed acrylic pressure-sensitive adhesive composition described in [1] to [3] is rotated by a Marlon mechanical stability tester for 15 minutes under a condition of 1000 rpm under a load of 15 kg of 150 g of the pressure-sensitive adhesive composition. Then, the coarse particles aggregated in the test vessel are filtered through a 100 mesh stainless steel wire mesh, and the weight (residue amount) after the residue remaining on the stainless steel wire mesh is dried at 150 ° C. for 30 minutes is measured. A water-dispersed acrylic pressure-sensitive adhesive composition, wherein the weight (%) of the aggregate calculated in (1) is 0.01% or less.
Aggregate weight (%) = (residue amount (g) / 150 (g) × solid content of adhesive composition (%))
× 100 (1)
[5] Water according to [3], wherein the ethylenically unsaturated monomer containing a carboxyl group is (meth) acrylic acid, and the ethylenically unsaturated monomer containing a hydroxyl group is 2-hydroxyethyl (meth) acrylate. Dispersed acrylic pressure-sensitive adhesive composition.
[6] An adhesive processed product using the water-dispersed acrylic adhesive composition according to [1] to [5].
[7] A pressure-sensitive adhesive processing characterized in that the water-dispersed acrylic pressure-sensitive adhesive composition according to [1] to [5] is applied to a substrate or a release material at a coating speed of 20 m / min to 1000 m / min. Product manufacturing method.

  The water-dispersed pressure-sensitive adhesive composition of the present invention is excellent in coating stability, and takes a large share when restarting after interruption of coating due to paper splicing or when coating such as high-speed coating Even under conditions, a smooth coated surface without streaks can be obtained. In addition, according to the method for manufacturing an adhesive processed product of the present invention, an adhesive processed product that can be applied at high speed and has excellent productivity can be manufactured as described above.

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

  Specific examples of the (meth) acrylic acid alkyl ester monomer of 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-, stearyl -, Etc., monomers containing acrylic acid ester or methacrylic acid ester 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, Furthermore, it is recommended to use a mixture of two or more (meth) acrylic acid alkyl ester monomers having 1 to 8 carbon atoms in the alkyl group. Preferred. When the carbon number of the alkyl group becomes too long, the polymerization reaction tends not to proceed smoothly.

  As a compounding quantity of the said (meth) acrylic acid ester monomer in a copolymer, 70-99 mass% normally, Furthermore, 75-99 mass% is preferable. If it is less than 70% by mass, sufficient adhesive strength as a pressure-sensitive adhesive tends to be difficult to obtain. On the other hand, when it exceeds 99% by mass, it tends to be difficult to obtain sufficient cohesive force as an adhesive.

  Moreover, as an ethylenically unsaturated monomer (a) which has a functional group which is a copolymerization component with the said (meth) acrylic acid ester monomer, specifically, as a monomer containing a hydroxyl group, for example, 2- Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 2-hydroxyvinyl 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, Conic acid, fumaric acid, citraconic acid, monomers containing glycidyl groups such as glycidyl acrylate, glycidyl methacrylate, glycidyl cinnamate, allyl glycidyl ether, vinylcyclohexene monoepoxide, monomers containing amide groups such as acrylamide , Methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, monomers containing sulfonic acid groups such as styrenesulfonic acid and its salts, 2-acrylamido-2-methylpropanesulfonic acid and its Salt, allyl sulfonic acid and its salt, methallyl sulfonic acid and its salt, etc., and these can be used as a mixture of two or more, but considering the price point, it contains a carboxyl group It is preferred to use dimer and hydroxyl group-containing monomer.

  As a compounding quantity of the said ethylenically unsaturated monomer which has a 2 or more types of functional group in a copolymer, it is 1-30 mass% normally with respect to 100 mass% of (meth) acrylic-acid alkylester monomers. Furthermore, 1-10 mass% is preferable. More preferably, it is 1-5 mass%.

  If the amount is less than 1% by mass, the polymerization and mechanical stability of the emulsion tend to be low, so that it tends to cause generation of coarse particles during polymerization and generation of aggregates under shear stress. Moreover, when it exceeds 30 mass%, it exists in the tendency for sufficient adhesive force to be hard to be acquired by the glass transition temperature of an adhesive becoming high.

  The water-dispersed acrylic pressure-sensitive adhesive composition of the present invention comprises, in addition to the above main components, a monomer (b) having two or more ethylenically unsaturated double bonds and other monoethylene as necessary. The unsaturated unsaturated monomer (c) may be copolymerized.

  First, as the monomer (b) having two or more ethylenically unsaturated double bonds, specifically, for example, butadiene, divinylbenzene, (poly) ethylene glycol diacrylate, (poly) ethylene glycol dimethacrylate , Trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, and the like. These may be used alone or in admixture of two or more.

Examples of the other monoethylenically unsaturated monomer (c) include vinyl monomers such as vinyl acetate, styrene, α-methylstyrene, divinylbenzene, acrylonitrile, methacrylonitrile, vinyl chloride, and vinylpyrrolidone. .
The amount of these monomer components used is generally in the range of 0 to 20% by mass with respect to 100% by mass of the two components.

  The water-dispersed tackifying resin emulsion used in the present invention is not particularly limited as long as it can substantially exhibit a tackifying function. Specifically, for example, natural or polymerized rosin, modified rosin, methyl ester, glycerin. Esters, pentaerythritol esters, triethylene glycol esters and rosin tackifying resins represented by hydrogenation thereof, α-pinene, β-pinene, camphor, dipentene, terpene tackifying resins represented by terpene phenol, carbon Petroleum-based tackifying resins represented by aliphatics mainly composed of fractions of 5 atoms, aromatics based on fractions of 9 carbons and copolymers thereof, alicyclics, and tar naphtha Coumarone-indene adhesive containing styrenes, indenes, coumarone, dicyclopentadiene, etc. Tackifying resin, alkylphenol tackifying resin represented by condensate of pt-butylphenol and acetylene, xylene tackifying resin obtained by reacting o-xylene, p-xylene, m-xylene with formalin, etc. These are emulsions in which a resin is dispersed in water, and these can be used alone or in admixture of two or more.

  The amount of these water-dispersed tackifying resin emulsions used is 0% by mass to 50% by mass in terms of solid content of the tackifying resin emulsion, based on the solid content of the main component (meth) acrylic acid alkyl ester copolymer. Although used in a range, it is preferably 0% by mass to 40% by mass, more preferably 0% by mass to 30% by mass. If the tackifying resin emulsion exceeds 50% by mass, the tackiness may decrease.

  2 or more types of ethylenically unsaturated monomers each having a different (meth) acrylic acid alkyl ester of the present invention and each having different functional groups, and if necessary, 2 or more ethylenically unsaturated double bonds There is no particular limitation on the method for producing a copolymer of a monomer having a monomer and other monoethylenically unsaturated monomers (hereinafter referred to as acrylic monomers), but generally known emulsion polymerization methods It is sufficient to do according to, and does not require a special method. That is, it is an emulsion polymerization method comprising water, the above acrylic monomer mixture, a surfactant, a chain transfer agent (polymerization degree modifier), 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. Nonionic surfactants such as anionic surfactants such as aryl sulfates, polyoxyethylene alkyl aryl ethers, polyoxyethylene sorbitan fatty acid esters, oxyethylene oxypropylene copolymers, and the like. Furthermore, it is possible to use a surfactant having a radical reactivity or a cationic surfactant obtained by adding a copolymerizable double bond such as a (meth) acryloyl group, a propenyl group, or an allyl group to the above surfactant. is there.

  As these surfactants, anionic surfactants are usually used. From the viewpoint of polymerization stability, it is preferable to use a mixture of an anionic surfactant and a nonionic surfactant. As the solid content of the surfactant, 0.1 to 10% by mass, preferably 0.1 to 7% by mass with respect to 100% by mass of the monomer constituting the main component (meth) acrylic acid alkyl ester. %, And more preferably 0.1 to 5% by mass.

  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 adhesive composition of this invention can also improve stability by performing 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 0.1 to 2.0 μm, preferably 0.2 to 1.0 μm, more preferably 0.3 to 1. 0.0 μm. If it is 0.1 μm or less, the viscosity increases and the solid content (concentration) cannot be sufficiently increased, and if it is 2.0 μm or more, problems such as sedimentation of particles may occur.

  The solid content (concentration) of the water-dispersed pressure-sensitive adhesive composition of the present invention is preferably 40% by mass to 75% by mass, and more preferably 50% by mass to 75% by mass. If the solid content is less than 40% by mass, a large amount of energy is required for drying. Therefore, it may not be said that it is excellent in high-speed coating in terms of practicality. If it exceeds 75% by mass, although the drying efficiency is increased, the viscosity at the time of production becomes too high, and problems such as poor operability are likely to occur, which may not be practical.

  The viscosity of the water-dispersed pressure-sensitive adhesive composition of the present invention is not particularly limited, but generally the viscosity at 60 rotations measured with a B-type viscometer is 100 to 15000 mPa · s, preferably 200. ˜12000 mPa · s, more preferably 300 to 10000 mPa · s. When the viscosity is less than 100 mPa · s, a phenomenon such as repellency or wrinkle tends to occur when coating on release paper, and the coating property tends to deteriorate. When the viscosity exceeds 15000 mPa · s, the handling property tends to deteriorate. is there.

The mechanical stability of the water-dispersed pressure-sensitive adhesive composition of the present invention was determined by rotating 150 g of the pressure-sensitive adhesive composition under a load of 15 kg under the condition of 1000 rpm for 15 minutes using a Marlon mechanical stability tester. The coarse particles aggregated in the container are filtered with a 100 mesh stainless steel wire mesh, and the weight (residue amount) after drying the residue remaining on the stainless steel wire mesh at 150 ° C. for 30 minutes is measured. It is necessary that the weight (%) of the agglomerates calculated in (1) is 0.01% or less, preferably 0.008% or less, and more preferably 0.006% or less.
Aggregate weight (%) = (residue amount (g) / 150 (g) × solid content of adhesive composition (%))
× 100 (1)

  In order to impart the required physical properties and performance to the pressure-sensitive adhesive composition obtained as described above, the types and amounts of the compounding agents used in the field of pressure-sensitive adhesives impair the effects of the present invention. 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.

  Since the water-dispersed pressure-sensitive adhesive composition of the present invention can cope with a wide range of coating speeds from 20 m / min to 1000 m / min, the coating speed of the coating machine to be used is appropriate for the line (drying speed, etc.). By setting the maximum speed that fits, it is possible to produce adhesive processed products efficiently.

  In the method for producing an adhesive processed article of the present invention, the coating operation of the water-dispersed adhesive composition is usually a roll coater, reverse roll coater, gravure coater, gravure reverse coater, blade coater, comma coater, kiss coater, slit. It can be easily carried out with a coating device such as a die coater, lip coater, curtain coater or the like.

  As described above, the pressure-sensitive adhesive composition of the present invention is excellent in coating stability, and has a large share at the time of restart after coating interruption due to paper splicing or at the time of coating such as high-speed coating. Even under such coating conditions, a good coated surface can be obtained, and an adhesive processed product with excellent productivity can be produced.

[Example]
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.
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)
Using LPA-3100 manufactured by Otsuka Electronics Co., Ltd., volume average particle diameter measured by dynamic light scattering method iii) Coating property Using a comma coater, coating is performed at a coating speed of 30 m / min. Number of seconds of streak loss that occurs when restarting after 5 minutes of interruption. If the number of lost seconds is 30 seconds or more, it cannot be used practically.

The monomers used in the examples and comparative examples are represented by the following abbreviations.
・ 2-Ethylhexyl acrylate… 2EHA
・ Butyl acrylate… BA
・ Methyl methacrylate ・ ・ ・ MMA
・ 2-hydroxyethyl methacrylate ・ ・ ・ HEMA
・ Acrylic acid ... AA
・ Methacrylic acid: MAA
・ N-dodecyl mercaptan ... nDM

  A temperature-controllable reactor equipped with a nitrogen introduction tube and a stirrer was charged with 205 parts of distilled water and 1.8 parts of potassium persulfate and heated to 70 ° C. under a nitrogen stream, and then 2EHA 394 parts, BA 155 parts, MMA 28 parts, Monomer mixture consisting of 18 parts of HEMA, 6 parts of AA, 6 parts of MAA, 0.2 part of nDM, 14 parts of anionic surfactant (Perex SSL: manufactured by Kao Corporation), nonionic surfactant (Neugen ET170: Daiichi Kogyo) (Manufactured by Pharmaceutical Co., Ltd.) 3 parts of monomer emulsion emulsified and dispersed in 169 parts of distilled water was continuously added in 4 hours, and the reaction was continued at 80 ° C. for 3 hours to complete the polymerization. After cooling and adjusting the pH to 7.5 to 8.5 with aqueous ammonia, the mixture was filtered through a wire mesh or the like to obtain an acrylic copolymer emulsion having a solid content of 60.9% and an average particle size of 0.43 μm. 10 parts of polymerized rosin-based tackifier resin emulsion (Haristar SK508H: manufactured by Harima Chemicals Co., Ltd.), Nopco 8034 (antifoaming agent: manufactured by San Nopco Co., Ltd.) is 0.2 with respect to the obtained acrylic copolymer emulsion. Part, 1.0 part of dialkyl sulfosuccinate sodium (Neocol SW-C: Daiichi Kogyo Seiyaku) is added, and an associative thickener (Adecanol UH-420: Asahi Denka Kogyo Co., Ltd.) is added. Thus, a pressure-sensitive adhesive composition was obtained. The amount of thickener added was such that the viscosity at 60 rotations at 23 ° C. with a B-type rotational viscometer was 3000 mPa · s.

  In the same apparatus as in Example 1, 220 parts of distilled water and 1.8 parts of potassium persulfate were charged, and the temperature was raised to 70 ° C. under a nitrogen stream, then 2EHA 391 parts, BA 156 parts, MMA 10 parts, HEMA 13 parts, AA 7 parts, nDM0 .2 parts of monomer mixture 14 parts of anionic surfactant (Perex SSL: Kao Co., Ltd.), 3 parts of nonionic surfactant (Neugen ET170: Daiichi Kogyo Seiyaku Co., Ltd.), distillation The monomer emulsion emulsified and dispersed in 184 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 and pH adjustment with aqueous ammonia. After adjusting to 7.5 to 8.5, the mixture was filtered through a wire mesh or the like to obtain an acrylic copolymer emulsion having a solid content of 58.0% and an average particle size of 0.49 μm. 10 parts of polymerized rosin-based tackifier resin emulsion (Haristar SK508H: manufactured by Harima Chemicals Co., Ltd.), Nopco 8034 (antifoaming agent: manufactured by San Nopco Co., Ltd.) is 0.2 with respect to the obtained acrylic copolymer emulsion. Part, 1.0 part of dialkyl sulfosuccinate sodium (Neocol SW-C: Daiichi Kogyo Seiyaku) is added, and an associative thickener (Adecanol UH-420: Asahi Denka Kogyo Co., Ltd.) is added. Thus, a pressure-sensitive adhesive composition was obtained. The amount of thickener added was such that the viscosity at 60 rotations at 23 ° C. with a B-type rotational viscometer was 3000 mPa · s.

[Comparative Example 1]
In the same apparatus as in Example 1, 205 parts of distilled water and 1.8 parts of potassium persulfate were charged, and the temperature was raised to 70 ° C. under a nitrogen stream, then 2EHA 394 parts, BA 155 parts, MMA 28 parts, AA 10 parts, MAA 10 parts, nDM0 .2 parts of monomer mixture 14 parts of anionic surfactant (Perex SSL: Kao Co., Ltd.), 3 parts of nonionic surfactant (Neugen ET170: Daiichi Kogyo Seiyaku Co., Ltd.), distillation The monomer emulsion emulsified and dispersed in 169 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 and pH adjustment with aqueous ammonia. After adjusting to 7.5 to 8.5, the mixture was filtered through a wire mesh or the like to obtain an acrylic copolymer emulsion having a solid content of 60.9% and an average particle size of 0.41 μm. 10 parts of polymerized rosin-based tackifier resin emulsion (Haristar SK508H: manufactured by Harima Chemicals Co., Ltd.), Nopco 8034 (antifoaming agent: manufactured by San Nopco Co., Ltd.) is 0.2 with respect to the obtained acrylic copolymer emulsion. Part, 1.0 part of dialkyl sulfosuccinate sodium (Neocol SW-C: Daiichi Kogyo Seiyaku) is added, and an associative thickener (Adecanol UH-420: Asahi Denka Kogyo Co., Ltd.) is added. Thus, a pressure-sensitive adhesive composition was obtained. The amount of thickener added was such that the viscosity at 60 rotations at 23 ° C. with a B-type rotational viscometer was 3000 mPa · s.

[Comparative Example 2]
In the same apparatus as in Example 1, 243 parts of distilled water and 1.8 parts of potassium persulfate were charged, and the temperature was raised to 70 ° C. in a nitrogen stream, and then 2EHA 387 parts, BA 148 parts, MMA 10 parts, AA 5 parts, nDM 0.2 parts. A monomer emulsion comprising 20 parts of an anionic surfactant (Perex SSL: manufactured by Kao Co., Ltd.) and 185 parts of distilled water is continuously added in 4 hours. The reaction was continued at 80 ° C. for 3 hours to complete the polymerization, then cooled, adjusted to pH 7.5 to 8.5 with aqueous ammonia, filtered through a wire mesh, etc. An acrylic copolymer emulsion having an average particle size of 0.45 μm was obtained. 10 parts of polymerized rosin-based tackifier resin emulsion (Haristar SK508H: manufactured by Harima Chemicals Co., Ltd.), Nopco 8034 (antifoaming agent: manufactured by San Nopco Co., Ltd.) is 0.2 with respect to the obtained acrylic copolymer emulsion. Part, 1.0 part of dialkyl sulfosuccinate sodium (Neocol SW-C: Daiichi Kogyo Seiyaku) is added, and an associative thickener (Adecanol UH-420: Asahi Denka Kogyo Co., Ltd.) is added. Thus, a pressure-sensitive adhesive composition was obtained. The amount of thickener added was such that the viscosity at 60 rotations at 23 ° C. with a B-type rotational viscometer was 3000 mPa · s.

  The evaluation results of the pressure-sensitive adhesive compositions obtained in the above examples and comparative examples are shown in Table 1.

  The pressure-sensitive adhesive composition of the present invention is excellent in coating stability, under coating conditions where a large share is required at the time of restart after coating interruption due to paper splicing, etc., or when coating such as high-speed coating However, a good coated surface can be obtained, and an adhesive processed product having excellent productivity can be produced.

Claims (7)

Two or more types of ethylenically unsaturated monomers (a) each having a (meth) acrylic acid alkyl ester as a main component and each having a different functional group, or ethylenically unsaturated monomers each having a different functional group ( a) obtained by copolymerizing two or more monomers (b) having at least two ethylenically unsaturated double bonds and / or other monoethylenically unsaturated monomers (c). A water-dispersed acrylic pressure-sensitive adhesive composition characterized by the above. The water according to claim 1, wherein the ethylenically unsaturated monomers (a) each having a different functional group are an ethylenically unsaturated monomer containing a carboxyl group and an ethylenically unsaturated monomer containing a hydroxyl group. Dispersed acrylic pressure-sensitive adhesive composition. A water-dispersed acrylic pressure-sensitive adhesive composition obtained by mixing the water-dispersed acrylic pressure-sensitive adhesive composition according to claim 1 with a water-dispersible tackifying resin emulsion. The water-dispersed acrylic pressure-sensitive adhesive composition according to any one of claims 1 to 3 was tested with a Marlon mechanical stability tester after rotating 150 g of the pressure-sensitive adhesive composition under a load of 15 kg at 1000 rpm for 15 minutes. The coarse particles agglomerated in the container are filtered through a 100-mesh stainless steel wire mesh, and the weight (residue amount) after drying the residue remaining on the stainless steel wire mesh at 150 ° C. for 30 minutes is calculated by the formula (1). A water-dispersed acrylic pressure-sensitive adhesive composition characterized in that the weight (%) of the aggregate is 0.01% or less.
Aggregate weight (%) = (residue amount (g) / 150 (g) × solid content of adhesive composition (%))
× 100 (1) The water-dispersed acrylic according to claim 3, wherein the ethylenically unsaturated monomer containing a carboxyl group is (meth) acrylic acid and the ethylenically unsaturated monomer containing a hydroxyl group is 2-hydroxyethyl (meth) acrylate. -Based pressure-sensitive adhesive composition. A pressure-sensitive adhesive product using the water-dispersed acrylic pressure-sensitive adhesive composition according to claim 1. A method for producing a pressure-sensitive adhesive product, comprising applying the water-dispersed acrylic pressure-sensitive adhesive composition according to claim 1 to a substrate or a release material at a coating speed of 20 m / min to 1000 m / min.