JP5991191B2 - Acrylic aqueous resin emulsion composition - Google Patents

Description

  The present invention relates to an acrylic aqueous resin emulsion composition, and more particularly to an acrylic aqueous resin emulsion composition having excellent viscosity stability over time.

Acrylic aqueous resin emulsions are those in which an acrylic resin is emulsified and dispersed in an aqueous medium, and are widely used in industry including paints, adhesives and adhesives.
Here, the aqueous resin emulsion is often commercialized after an appropriate neutralizing agent, a thickening agent, or the like is blended depending on the application and adjusted to a desired pH, viscosity, or the like. By controlling the pH, viscosity, and the like in this way, for example, coating suitability suitable for the coating apparatus or coating method to be used, liquid feeding suitability suitable for the usage method, and the like can be imparted.

When adjusting the viscosity by adding a thickener to an aqueous resin emulsion, it is generally performed by adding a specified amount of the thickener to the base emulsion all at once or divided and mixing thoroughly. It is.
Patent Document 1 discloses a water-dispersed acrylic pressure-sensitive adhesive composition containing a specific acrylic emulsion and describes that various thickeners can be added thereto. In the examples, an example is shown in which the base emulsion is actually adjusted to a desired viscosity using an alkali-soluble emulsion thickener.
Patent Document 2 describes an example in which the viscosity of an acrylic emulsion-type pressure-sensitive adhesive composition was adjusted using a urethane thickener as a thickener in the examples.

However, depending on the type of acrylic emulsion used as a base, the type of thickener used, or the conditions for viscosity adjustment, the viscosity stability of the resulting acrylic aqueous resin emulsion composition is poor, and there is a problem that the viscosity increases over time. It was.
Although there are few examples for improving the viscosity stability of the acrylic aqueous resin emulsion as described above, a single monomer mainly composed of a (meth) acrylic acid ester monomer in the presence of polyvinyl alcohol (PVA). A result is disclosed in which the storage stability of an emulsion obtained by emulsion polymerization of a monomer and oxidation treatment during and / or after emulsion polymerization is improved (Patent Document 3).

JP 2011-93956 A JP 2003-96420 A JP 2007-238714 A

However, Patent Document 1 and Patent Document 2 do not describe at all the viscosity stability of a product obtained by adding a thickener to an acrylic aqueous resin emulsion.
Patent Document 3 is limited to the case where PVA is used as a protective colloid. In addition, problems such as an increase in the number of oxidation treatment steps lead to a delay in manufacturing time and an increase in cost. Further, when PVA is used, there is a concern about the effect on the product liquidity such as particle diameter.

As described above, an acrylic aqueous resin emulsion composition having good viscosity stability over time is desired, but a sufficient solution has not been proposed.
The subject of this invention is providing the acrylic type aqueous resin emulsion composition which can solve the said subject.

  As a result of intensive studies in view of the above problems, the present inventors have found that a viscosity with time can be obtained by adding a nonionic surfactant having a phenoxy group which may have a substituent to the acrylic aqueous resin emulsion composition. It was learned that the stability was improved and the present invention was completed.

The present invention is as follows.
[1] An acrylic aqueous resin emulsion composition comprising an acrylic polymer, a nonionic surfactant having a phenoxy group which may have a substituent, and a thickener,
The thickener comprises a thickener selected from urethane-based associative thickeners and alkali-soluble thickeners;
An acrylic aqueous resin emulsion composition having a viscosity of 3,000 to 50,000 mPa · s and a solid content of 50 to 70% by mass.
[2] The acrylic aqueous resin emulsion composition according to [1], wherein the pH is 6.0 to 10.0.
[3] The acrylic aqueous resin emulsion composition as described in [1] or [2 ] above, wherein the substituent has an aromatic substituent.
[4] The content of the nonionic surfactant having a phenoxy group which may have a substituent is 0.01 to 5 parts by mass in 100 parts by mass of the acrylic aqueous resin emulsion. The acrylic aqueous resin emulsion composition according to any one of [1] to [3] .
[5] A method for producing an acrylic aqueous resin emulsion composition,
A step of mixing a nonionic surfactant having a phenoxy group which may have a substituent and a thickener in an aqueous resin emulsion containing an acrylic polymer;
The viscosity of the said acrylic type aqueous resin emulsion composition is 3,000-50,000 mPa * s, and solid content is 50-70 mass%.
[6] The method for producing an acrylic aqueous resin emulsion composition according to [5], wherein the thickener includes a thickener selected from a urethane-based associative thickener and an alkali-soluble thickener.

  According to the acrylic aqueous resin emulsion composition of the present invention, an acrylic aqueous resin emulsion composition having excellent viscosity stability over time can be obtained. Also, there is no effect on product functions such as adhesive properties.

The present invention relates to an acrylic aqueous resin composition comprising a specific nonionic surfactant and a thickener and having excellent viscosity stability over time.
The present invention will be described in detail below. In the present specification, acrylic acid and / or methacrylic acid is represented as (meth) acrylic acid.

  In the present invention, the viscosity stability of the composition is improved by including a nonionic surfactant having a phenoxy group in the molecule which may have a substituent in the acrylic aqueous resin emulsion composition. Can do.

The nonionic surfactant is not particularly limited as long as it has a phenoxy group or a phenoxy group having a substituent in the molecule, but the substituent is preferably an aromatic substituent. This is preferable because of the high effect of imparting.
Specific examples of the nonionic surfactant having a phenoxy group having an aromatic substituent include polyoxyethylene monostyrenated phenyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene monobenzyl phenyl ether, polyoxyethylene Examples thereof include ethylene dibenzyl phenyl ether and polyoxyethylene tribenzyl phenyl ether.

  The polyoxyalkylene chain, which is the hydrophilic group portion of the nonionic surfactant, may have either a hydroxyl group type or an alkoxy group type terminal. The polyoxyalkylene chain includes a structure in which the repeating unit is oxyethylene, a structure in which it is oxypropylene, a structure in which oxyethylene units and oxypropylene units are randomly linked, a repeating portion of oxyethylene units and oxypropylene units. The structure etc. which the repeating part continued are mentioned.

  The content of the nonionic surfactant is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 2 parts by mass, and still more preferably 0.1 per 100 parts by mass of the acrylic aqueous resin emulsion. -1.0 mass part. When the amount of the nonionic surfactant used is less than 0.01 parts by mass, the viscosity stability over time may be deteriorated. On the other hand, when the emulsifier exceeds 5 parts by mass, the emulsifier absorbs moisture and absorbs water, which may cause deterioration of water resistance and performance such as adhesive strength.

The acrylic polymer of the present invention can be obtained by polymerizing a monomer mixture containing a (meth) acrylic acid ester monomer as a main component. Here, having a (meth) acrylic acid ester monomer as a main component means that the use ratio of the (meth) acrylic acid ester monomer is 50% by mass or more in the monomer mixture, Preferably it is 60 mass% or more, More preferably, it is 70 mass% or more.
Examples of the (meth) acrylic acid ester monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and (meth) acrylic acid n. -Butyl, isobutyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n (meth) acrylate -(Meth) acrylic acid alkyl esters such as nonyl, isononyl (meth) acrylate, n-decyl (meth) acrylate, lauryl (meth) acrylate; cyclohexyl (meth) acrylate, methyl cyclohexyl (meth) acrylate , T-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate Aliphatic vinyl monomers such as isobornyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol ( Examples thereof include hydroxyl group-containing monomers such as (meth) acrylate, polypropylene glycol (meth) acrylate and polyethylene-polypropylene glycol mono (meth) acrylate, and one or more of these can be used.
Among these, from the viewpoint of emulsion production stability, it is preferable to use (meth) acrylic acid alkyl esters.

  The acrylic copolymer of the present invention may use other monomers copolymerizable with the (meth) acrylic acid ester monomer in accordance with the intended use. Examples of the copolymerizable monomer include α, β-ethylenically unsaturated carboxylic acid monomers such as (meth) acrylic acid, itaconic acid, maleic acid and fumaric acid; styrene, α-methylstyrene, vinyltoluene Vinyl aromatic monomers such as itaconic acid monoethyl ester, fumaric acid monobutyl ester, etc. monoalkyl esters of unsaturated dicarboxylic acids; acrylamide, N-methylol acrylamide, N-methoxymethyl acrylamide, N-methoxybutyl acrylamide Ethylenically unsaturated carboxylic acid amides and N-substituted compounds such as: unsaturated alcohols such as allyl alcohol; (meth) acrylonitrile, vinyl acetate, glycidyl (meth) acrylate, diacetone acrylamide, etc. One or more can be used .

The acrylic polymer of the present invention may be cross-linked if necessary.
Crosslinking is performed by a crosslinking reaction between a polymer into which a reactive functional group such as a carboxyl group, a sulfonic acid group, a hydroxyl group, an amino group, and a carbonyl group is introduced and a crosslinking agent having a crosslinkable functional group. In addition, methylene bis (meth) acrylamide, ethylene bis (meth) acrylamide, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, divinylbenzene, etc. having two or more vinyl groups in one molecule Crosslinking is also possible by copolymerization of crosslinkable monomers, or by introducing monomers having self-crosslinkable functional groups such as methylol group-containing monomers and hydrolyzable silyl group-containing monomers. .

The cross-linking agent is not particularly limited as long as it can undergo a cross-linking reaction with the reactive functional group. For example, it is selected from cross-linking agents such as epoxy, isocyanate, hydrazide, carbodiimide, oxazoline, and metal cross-linking agents. 1 type (s) or 2 or more types can be used.
Although the addition amount of a crosslinking agent is suitably adjusted with the intended use and performance, 0.05-10 mass parts is preferable with respect to 100 mass parts of polymers, and 0.1-5 mass parts is further more preferable.

  The acrylic polymer of the present invention can be obtained by polymerizing the above monomer mixture by a known polymerization method. The polymerization method is not particularly limited, and can be obtained in the form of an aqueous resin emulsion by a polymerization method using an aqueous medium such as emulsion polymerization, microemulsion polymerization, and miniemulsion polymerization. Moreover, you may manufacture by performing a solvent removal and neutralization phase inversion after solution polymerization.

When employing the above emulsion polymerization, an emulsifier may be used to stabilize the monomer mixture and the produced polymer particles.
As the emulsifier to be used, known emulsifiers used in usual emulsion polymerization can be used. For example, various emulsifiers such as an anionic emulsifier, a nonionic emulsifier, a cationic emulsifier, and a zwitterionic emulsifier can be used. As anionic emulsifiers, dialkyl sulfosuccinate, alkylbenzene sulfonate, alkyl sulfate, polyoxyethylene alkylphenyl ether sulfate, polyoxyethylene alkyl diphenyl ether sulfate, polyoxyethylene alkyl ether sulfate, alkyl diphenyl ether disulfonate , Polyoxyethylene polycyclic phenyl ether sulfate, polyoxyalkylene disulfonate, polymer emulsifier and the like. Nonionic emulsifiers include polyoxyethylene higher alcohol ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl diphenyl ethers, polyoxyethylene-polyoxypropylene block copolymers, acetylenic diol emulsifiers, sorbitan higher fatty acid esters. Polyoxyethylene sorbitan higher fatty acid esters, polyoxyethylene higher fatty acid esters, glycerin higher fatty acid esters, polycarboxylic acid-based polymer emulsifier, polyvinyl alcohol and the like. Examples of the cationic emulsifier include alkyl (amido) betaines and alkyldimitylamine oxides, and examples of the special emulsifier include a fluorine-based emulsifier and a silicone-based emulsifier. These emulsifiers may be used alone or in combination of two or more.

  Although the usage-amount of an emulsifier is selected by the kind, polymerization conditions, etc., it is 0.05-20 mass parts normally per 100 mass parts of monomers, Preferably it is 0.1-15 mass parts, More preferably, it is 0. 5 to 10 parts by mass. When the amount of the emulsifier used is small, the stability during production tends to be insufficient, and aggregates and the like are likely to be formed. It causes a drop in performance such as power.

A known method can be adopted as a method of emulsifying the monomer mixture. Specifically, an emulsion is obtained by mixing each monomer, an emulsifier, and the like in an aqueous medium, and then stirring and mixing at normal pressure or under pressure.
As an apparatus for stirring and mixing, various mixers such as a homomixer, various emulsifiers such as a colloid mill, a high-pressure emulsifier, and a high-pressure discharge type emulsifier are used.

  As the polymerization initiator, known radical polymerization initiators such as peroxides and azo compounds can be used, and these radical polymerization initiators can also be used in combination. In addition, peroxides and ascorbic acid, sodium ascorbate, sodium erythorbate, tartaric acid, citric acid, metal salts of formaldehyde sulfoxylate, sodium thiosulfate, sodium sulfite, sodium bisulfite, sodium metabisulfite, secondary chloride Polymerization can also be performed by a redox polymerization initiation system in combination with a reducing agent such as iron.

Examples of the peroxide include hydrogen peroxide; inorganic peroxides such as persulfates (sodium persulfate, ammonium persulfate, potassium persulfate, etc.); hydroperoxides (cumene hydroperoxide, paramentane hydroperoxide, tert -Butyl hydroperoxide, etc.), dialkyl peroxide (tert-butyl cumyl peroxide, dicumyl peroxide, etc.), diacyl peroxide, peroxy ester (tert-butyl peroxylaurate, tert-butyl peroxybenzoate, etc.) And organic peroxides such as benzoyl peroxide, lauroyl peroxide, peracetic acid and persuccinic acid. These can be used alone or in combination of two or more.
Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), and 2,2′-azobis (2-methylbutyronitrile). 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) and the like. These can be used alone or in combination of two or more.

  Although the usage-amount of a radical polymerization initiator is selected by the kind, superposition | polymerization conditions, etc., it is 0.01-10 mass parts normally with respect to 100 mass parts of said monomers.

  The polymerization of the emulsion is usually performed in a reaction system heated in an aqueous medium with stirring and reflux cooling. Here, the addition method of raw material components such as the emulsion and the initiator may be any of a batch addition method, a continuous addition method, and a divided addition method. In the case of the continuous addition method, the supply rate may be constant or indefinite. In addition, in the case of the divided addition method, the addition interval of the raw material components may be constant or indefinite.

  As the aqueous medium, water alone or a mixture of water and a water-soluble organic solvent (alcohol, ketone, ether, dimethyl sulfoxide, dimethylformamide, etc.) can be used. When this aqueous medium is a mixture, the content of water is usually 30% by mass or more when the aqueous medium is 100% by mass.

  The polymerization temperature of the monomer in the above polymerization is appropriately selected depending on the type of monomer and the type of radical polymerization initiator, and is usually 40 to 95 ° C.

  The acrylic aqueous resin emulsion composition of the present invention contains a thickener. Regardless of the type of thickener, various thickeners such as urethane-based associative thickeners, water-soluble polymer-based thickeners, and alkali-soluble thickeners can be used. Among these, alkali-soluble thickeners are preferable because viscosity adjustment is relatively simple.

  Alkali-soluble thickeners generally have a high molecular weight polymer with a large amount of acid groups such as carboxyl groups introduced as the main component, and form a network structure by adjusting the pH from neutral to alkaline with an alkaline agent. It exhibits a thickening effect. The alkali-soluble thickener in the present invention includes an alkali swelling thickener.

  A urethane-based associative thickener generally has a polymer having a urethane bond in the molecular structure as a main component, and forms a network structure by associating with an emulsion, thereby exhibiting a thickening effect.

  The water-soluble polymer thickener generally has a water-soluble high molecular weight polymer as a main component, and forms a network structure by associating with an emulsion and exhibits a thickening effect. There are natural water-soluble thickeners typified by carboxymethylcellulose and synthetic water-soluble thickeners typified by vinyl polymers.

  The addition amount of the thickener is appropriately adjusted depending on the type of the base emulsion and the target viscosity, but is preferably 0.1 to 10 parts by mass, and 0.1 to 5 parts by mass per 100 parts by mass of the aqueous resin emulsion. It is more preferable to use parts.

  The pH of the acrylic aqueous resin emulsion composition after viscosity adjustment is preferably 6.0 to 10.0, and more preferably 7.0 to 9.0. If the pH is lower than 6.0, the thickening effect by the thickener may be insufficient. On the other hand, when it is higher than 10.0, problems such as safety and odor during handling occur.

  The solid content of the acrylic aqueous resin emulsion composition of the present invention is required to be 50 to 70% by mass, and preferably 50 to 65% by mass. When the solid content is lower than 50% by mass, it is difficult for the product viscosity to increase over time. On the other hand, when it is higher than 70% by mass, industrial production is generally difficult.

  The viscosity of the acrylic aqueous resin emulsion composition of the present invention is required to be 3,000 to 50,000 mPa · s, and preferably 5,000 to 30,000 mPa · s. When the viscosity is lower than 3,000 mPa · s, it is difficult for the emulsion composition to thicken with time, and the problem of viscosity stability hardly occurs. On the other hand, when it is higher than 50,000 mPa · s, the coating suitability deteriorates.

  In addition, the aqueous resin emulsion composition in the present invention includes a dispersant, an antifoaming agent, a tackifier, a plasticizer, a lubricant, a film forming auxiliary, a fiber auxiliary, a cleaning agent, and an antistatic agent depending on applications. Agents, leveling agents, wetting agents, leveling agents, crosslinking agents, and other general additives may be added.

  As crosslinking agents, isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, polyvalent metal salt crosslinking agents, metal chelate crosslinking agents, keto-hydrazide crosslinking agents, oxazoline crosslinking agents, carbodiimide crosslinking agents Silane-based crosslinking agents, glycidyl (alkoxy) epoxysilane-based crosslinking agents, and the like can be used.

Hereinafter, the present invention will be specifically described based on examples. In the following description, “part” means part by mass, and “%” means mass%.
Moreover, the acrylic aqueous resin emulsion composition obtained in each example was evaluated by the method described below.
a) About 1 g of a solid content measurement sample was weighed (a), then the residue after drying for 30 minutes in an air dryer 155 ° C. was measured (b), and calculated from the following formula. A weighing bottle was used for the measurement. Other operations were in accordance with JIS K 0067-1992 (chemical product weight loss and residue test method).
Solid content (%) = (b / a) × 100

b) Viscosity The viscosity after 90 seconds at a rotational speed of 12 rpm was measured using a BM viscometer under the condition of a liquid temperature of 25 ° C.
The viscosity of the acrylic aqueous emulsion composition was measured on the day of preparation and after storage for 1 month at 25 ° C. to evaluate the viscosity stability. The increase in viscosity after one month was determined based on the following criteria.
A: Increase in viscosity is 500 mPa · s or less.
○: Viscosity increase exceeds 500 mPa · s and is 1,000 mPa · s or less.
Δ: Viscosity increase exceeds 1,000 mPa · s and is 2,000 mPa · s or less.
X: The increase in viscosity exceeds 2,000 mPa · s.

c) pH
It measured with the pH meter on the conditions of liquid temperature 25 degreeC.

d) Adhesive strength The acrylic aqueous resin emulsion obtained in each of the following examples was applied to the surface of a polyethylene terephthalate (PET) film having a thickness of 50 μm so that the film thickness after drying was 35 to 40 μm. Subsequently, the adhesive sheet was produced by drying at 100 degreeC for 2 minute (s) with a hot air circulation dryer.
Using the pressure-sensitive adhesive sheet obtained above as a sample, the 180-degree peel strength against the SUS plate was measured according to JIS Z 0237-2009 (pressure-sensitive adhesive tape / pressure-sensitive adhesive sheet test method), and the obtained value was defined as the pressure-sensitive adhesive force. The determination was performed according to the following criteria.
○: Adhesive strength is 9 N / 25 mm or more Δ: Adhesive strength is 6 N / 25 mm or more and less than 9 N / 25 mm ×: Adhesive strength is less than 6 N / 25 mm

e) Holding power The same pressure-sensitive adhesive sheet as that used in the measurement of the pressure-sensitive adhesive force was used as a sample, and measurement was performed according to JIS Z 0237-2009 (pressure-sensitive adhesive tape / pressure-sensitive adhesive sheet test method). The time until peeling off by applying a load of 1 kg at a measurement temperature of 40 ° C. was measured, and the holding time was defined as holding power. The measurement was performed for 10 hours and judged according to the following criteria.
○: Hold even after 10 hours ×: Fall before 10 hours

Production Example 1
Prepare a reaction vessel equipped with a stirrer, reflux condenser, dripping tank and thermometer. In the dripping tank, 20 parts of ion-exchanged water, dodecylbenzenesulfonic acid (trade name “Neopelex G-15” manufactured by Kao Corporation, effective Component 16%) 6 parts, 2-ethylhexyl acrylate (hereinafter referred to as “HA”) 90 parts, methyl methacrylate (hereinafter referred to as “MMA”) 7 parts, methacrylic acid (hereinafter referred to as “MAA”) 3 parts The emulsion was prepared by charging and stirring. The reaction vessel was charged with 25 parts of ion exchange water and heated to 85 ° C. with stirring. After 15 minutes, the equivalent of 0.1% of the emulsion in the dropping tank was added, and after 5 minutes, 2 parts of a 25% aqueous solution of ammonium persulfate (hereinafter referred to as “APS”) was added. After 5 minutes, the remainder of the emulsion in the dropping tank was continuously dropped into the reaction vessel over 4 hours and subjected to emulsion polymerization, followed by further aging for 1 hour. 30 minutes after the start of aging, 1 part of a 13% APS aqueous solution was continuously dropped into the reaction vessel over 30 minutes, and the internal temperature of the reaction solution was maintained at 85 ° C. during the polymerization and aging period. After completion of the aging, the system is cooled, 0.2 parts of t-butyl hydroperoxide and 0.2 parts of hydrosulfite sodium are added at 70 ° C., and the mixture is filtered through 200 mesh polyethylene to obtain an acrylic aqueous resin emulsion. Got.

Example 1
While stirring, 100 parts of the acrylic aqueous resin emulsion obtained in Production Example 1 was added with 0.25 part of polyoxyethylene distyrenated phenyl ether (trade name “Emulgen A-60” manufactured by Kao Corporation). Furthermore, an alkali-soluble thickener (trade name “Aron B-500” manufactured by Toagosei Co., Ltd.), 25% ammonia aqueous solution and ion-exchanged water are appropriately used, the solid content is 59%, pH is 7.5, viscosity is Was adjusted to 6,100 mPa · s. In this way, an acrylic aqueous resin emulsion composition A1 was obtained.
The evaluation results of the obtained emulsion composition are shown in Table 1.

Example 2
An acrylic aqueous resin emulsion composition A2 was obtained in the same manner as in Example 1 except that 0.05 part of Emulgen A-60 was added.
The evaluation results of the obtained emulsion composition are shown in Table 1.

Example 3
An acrylic aqueous resin emulsion composition A3 was obtained in the same manner as in Example 1 except that 3 parts of Emulgen A-60 was added.
The evaluation results of the obtained emulsion composition are shown in Table 1.

Example 4
In Example 1, 0.25 part of polyoxyethylene tribenzylphenyl ether (trade name “Emulgen B-66” manufactured by Kao Corporation) was added instead of Emulgen A-60 added to the acrylic aqueous resin emulsion. Except for this point, an acrylic aqueous resin emulsion composition A4 was obtained in the same manner as in Example 1.
The evaluation results of the obtained emulsion composition are shown in Table 1.

Example 5
Instead of Emulgen A-60 added later to the acrylic aqueous resin emulsion in Example 1, 0.25 part of polyoxyalkylene alkylphenyl ether (trade name “Emulgen L-40”, manufactured by Kao Corporation) was added. Except for this point, an acrylic aqueous resin emulsion composition A5 was obtained in the same manner as in Example 1.
The evaluation results of the obtained emulsion composition are shown in Table 1.

Comparative Example 1
In Example 1, Emulgen A-60 was not added to the acrylic aqueous resin emulsion. Except for this point, an acrylic aqueous resin emulsion composition B1 was obtained in the same manner as in Example 1.
The evaluation results of the obtained emulsion composition are shown in Table 2.

Comparative Example 2
In Example 1, 0.25 part of polyoxyethylene alkyl ether (trade name “Emulgen 1135S-70”, manufactured by Kao Corporation) was added in place of Emulgen A-60 added later to the acrylic aqueous resin emulsion. Except for this point, an acrylic aqueous resin emulsion composition B2 was obtained in the same manner as in Example 1.
The evaluation results of the obtained emulsion composition are shown in Table 2.

Comparative Example 3
In Example 1, 0.25 part of polyoxyalkylene alkyl ether (trade name “Emulgen LS-110” manufactured by Kao Corporation) was added instead of Emulgen A-60 added to the acrylic aqueous resin emulsion. Except for this point, an acrylic aqueous resin emulsion composition B3 according to this comparative example was obtained in the same manner as in Example 1.
The measured values of the viscosity and holding power of the obtained emulsion composition are shown in Table 2.

Comparative Example 4
Instead of Emulgen A-60 added later to the acrylic aqueous resin emulsion in Example 1, anionic surfactant sodium polyoxyethylene alkyl ether sulfate (trade name “Latemul E-118B” manufactured by Kao Corporation) 0.25 Parts were added. Except for this point, an acrylic aqueous resin emulsion composition B4 was obtained in the same manner as in Example 1.
The evaluation results of the obtained emulsion composition are shown in Table 2.

Comparative Example 5
Instead of emulgen A-60 added later to the acrylic aqueous resin emulsion in Example 1, anionic surfactant sodium polyoxyethylene polycyclic phenyl ether sulfate (manufactured by Nippon Emulsifier Co., Ltd., trade name “New Coal 714SN”) 0 .25 parts were added. Except for this point, an acrylic aqueous resin emulsion composition B5 according to this comparative example was obtained in the same manner as in Example 1.
The evaluation results of the obtained emulsion composition are shown in Table 2.

Abbreviations of the surfactants used in Tables 1 and 2 are as follows.
A-60: Emulgen A-60 (manufactured by Kao Corporation)
B-66: Emulgen B-66 (manufactured by Kao Corporation)
L-40: Emulgen L-40 (manufactured by Kao Corporation)
1135S-70: Emulgen 1135S-70 (manufactured by Kao Corporation)
LS-110: Emulgen LS-110 (manufactured by Kao Corporation)
E-118B: Latemul E-118B (manufactured by Kao Corporation)
714SN: New Call 714SN (Nippon Emulsifier Co., Ltd.)

  As shown in Table 1, the acrylic aqueous resin emulsions obtained in Examples 1 to 5 had good viscosity stability, and no deterioration in product properties such as adhesive strength and holding power was observed. In particular, when a phenoxy group-containing nonionic surfactant having an aromatic substituent is used, the effect of imparting viscosity stability is higher compared to those having no aromatic substituent. (Examples 1, 4 and 5).

  On the other hand, as shown in Table 2, in Comparative Example 1 in which A-60 was not added, the viscosity significantly increased over time. Moreover, also in Comparative Examples 2 and 3 to which a nonionic surfactant having a structure different from that of the present invention was added, viscosity stability could not be ensured. Comparative Examples 4 and 5 are experimental examples using an anionic surfactant. Among them, Comparative Example 5 is an example using a surfactant having a phenoxy group substituted with an aromatic substituent. The viscosity stability was poor, and the physical properties such as adhesive strength were adversely affected.

  With the acrylic aqueous resin emulsion composition of the present invention, an acrylic aqueous resin emulsion composition having excellent viscosity stability over time can be obtained. This is useful for acrylic aqueous resin emulsion compositions used for various applications such as paints, adhesives, and pressure-sensitive adhesives.

Claims (6)

An acrylic aqueous resin emulsion composition comprising an acrylic polymer, a nonionic surfactant having a phenoxy group which may have a substituent, and a thickener,
The thickener comprises a thickener selected from urethane-based associative thickeners and alkali-soluble thickeners;
An acrylic aqueous resin emulsion composition having a viscosity of 3,000 to 50,000 mPa · s and a solid content of 50 to 70% by mass. The acrylic aqueous resin emulsion composition according to claim 1, wherein the pH is 6.0 to 10.0. Wherein the substituent is an aqueous acrylic resin emulsion composition according to claim 1 or 2, characterized in that it is a substituent of an aromatic system. The content of the nonionic surfactant having a phenoxy group which may have a substituent is 0.01 to 5 parts by mass in 100 parts by mass of the acrylic aqueous resin emulsion. The acrylic aqueous resin emulsion composition according to any one of -3 . A method for producing an acrylic aqueous resin emulsion composition,
A step of mixing a nonionic surfactant having a phenoxy group which may have a substituent and a thickener in an aqueous resin emulsion containing an acrylic polymer;
The viscosity of the said acrylic type aqueous resin emulsion composition is 3,000-50,000 mPa * s, and solid content is 50-70 mass%. The method for producing an acrylic aqueous resin emulsion composition according to claim 5, wherein the thickener comprises a thickener selected from a urethane-based associative thickener and an alkali-soluble thickener.