JP2013116990A - Method for producing water-based resin emulsion composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a water-based resin emulsion composition, which does not generate agglomerated materials or the like when adjusting a viscosity or the like of the emulsion by adding a thickener thereto, and has favorable viscosity stability after adjustment.SOLUTION: The production method includes adding the thickener to a base emulsion in two additions. Further, it brings about more excellent effect on suppression of agglomerated materials generation or improvement of viscosity stability to adjust the pH of the base emulsion to 7 to 10 when adding the thickener.

Description

  The present invention relates to a method for producing a water-based resin emulsion composition, and more specifically, when the viscosity of a water-based resin emulsion is adjusted with an alkali-soluble thickener or the like, the generation of aggregates is suppressed, and the viscosity after adjustment is reduced. The present invention relates to a method for producing an aqueous resin emulsion composition having excellent stability.

A water-based resin emulsion is an emulsion in which a synthetic resin such as acrylic resin, vinyl acetate resin and styrene resin, or natural resin such as natural rubber is emulsified and dispersed in an aqueous medium, including paints, adhesives and adhesives. Widely used in industry.
Here, the water-based resin emulsion is often commercialized after an appropriate neutralizing agent, a thickening agent, or the like is blended in accordance with 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.

Usually, when adjusting a viscosity by adding a thickener to a water-based resin emulsion, a specified amount of a thickener is added to the base emulsion at once and sufficiently mixed with stirring.
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.

JP 2011-93956 A JP 2003-96420 A

  However, the inventors, in the study of obtaining a product by adding a thickener to the aqueous resin emulsion, even if the base emulsion and the thickener to be added are the same, depending on the operating conditions, aggregates and the like may occur The problem was that the viscosity of the emulsion product after adjustment changed with time. The description regarding such a problem is not shown at all in Patent Document 1 and Patent Document 2, and furthermore, these patent documents show that a thickener was used for viscosity adjustment. However, there is no description about the specific addition method.

As described above, there is a demand for a method for producing an aqueous resin emulsion composition that does not generate aggregates or the like when the viscosity is adjusted by adding a thickener to the water-based resin emulsion, and has good viscosity stability even after the adjustment. However, the actual situation is that no sufficient solution has been proposed.
The subject of this invention is providing the manufacturing method of the 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 the addition of the thickener is divided into two or more to suppress the generation of aggregates and improve the viscosity stability after adjustment. As a result, the present invention was completed.

The present invention is as follows.
1. A method for producing an aqueous resin emulsion composition, comprising adding and mixing a thickener to adjust the viscosity of an aqueous resin emulsion, and adding the thickener in two or more portions.
2. 2. The method for producing an aqueous resin emulsion composition according to 1 above, wherein the thickener is an alkali-soluble thickener.
3. 3. The method for producing an aqueous resin emulsion composition as described in 1 or 2 above, wherein the pH when adding the thickener is 7 to 10.

  According to the method for producing a water-based resin emulsion composition of the present invention, it is possible to obtain a water-based resin emulsion composition that suppresses the generation of aggregates due to the addition of a thickener and is excellent in viscosity stability. The aqueous resin emulsion composition obtained by the production method of the present invention is useful as an aqueous resin emulsion composition used for various applications such as paints, adhesives, and pressure-sensitive adhesives.

The present invention relates to a method for producing an aqueous resin emulsion composition, wherein the thickener is added in two or more portions.
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.

  The aqueous resin emulsion in the present invention is obtained by emulsifying and dispersing various synthetic resins and natural resins in an aqueous medium. Among them, synthetic resins typified by acrylic resins are widely used because they have advantages such as high quality stability and a high degree of freedom in functional design by selecting constituent monomers.

  The synthetic resin can be obtained by polymerizing a monomer mixture containing an ethylenically unsaturated monomer. Examples of the ethylenically unsaturated monomer include (meth) acrylic acid alkyl ester, unsaturated carboxylic acid. (Meth) acrylic acid ester containing acid, unsaturated acid anhydride, (meth) acrylic acid hydroxyalkyl ester, aromatic vinyl compound, nitrogen-containing unsaturated compound, unsaturated sulfonic acid, unsaturated amide, polyalkylene oxide skeleton Etc. These may be used alone or in combination of two or more.

As the (meth) acrylic acid alkyl ester, an alkyl group is preferably a hydrocarbon group having 1 to 18 carbon atoms, for example, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid. n-propyl, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, (meth) acrylic acid n-hexyl, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, (meth) acrylic acid Decyl, dodecyl (meth) acrylate, stearyl (meth) acrylate, octadecyl (meth) acrylate , (Meth) acrylate, cyclohexyl (meth) acrylate, phenyl include benzyl (meth) acrylate and the like. These can be used alone or in combination of two or more. As said (meth) acrylic-acid alkylester, from what viewpoints, such as polymerizability and availability, the thing whose carbon number of an alkyl group is 1-12 is more preferable, and it is a C4-C12 hydrocarbon group Is particularly preferred.
The content ratio of the (meth) acrylic acid alkyl ester is appropriately adjusted depending on the application to be used. When the total of the ethylenically unsaturated monomer mixture is 100% by mass, 30 to 100% by mass is preferable, and 40 to 40%. 95 mass% is more preferable, and 50-90 mass% is still more preferable.

Examples of the unsaturated carboxylic acid (carboxyl group-containing monomer) include acrylic acid, methacrylic acid, maleic acid, and itaconic acid. These can be used alone or in combination of two or more. Acrylic acid and methacrylic acid are preferably used because of their high stability during polymerization.
If the content of the unsaturated carboxylic acid is too large, there is a risk of gelation during polymerization in the polymerization of the aqueous medium, and if it is too small, the polymerization stability may be lowered. When the total of the unsaturated unsaturated monomer mixture is 100% by mass, 0.1 to 20% by mass is preferable, 0.5 to 10% by mass is more preferable, and 1 to 5% by mass is still more preferable.

  Examples of the (meth) acrylic acid hydroxyalkyl ester include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. , (Meth) acrylic acid 3-hydroxybutyl, (meth) acrylic acid 4-hydroxybutyl and the like. These can be used alone or in combination of two or more.

  Examples of the aromatic vinyl compound include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, vinyltoluene, β-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinylxylene, vinylnaphthalene and the like. It is done. These can be used alone or in combination of two or more.

  Examples of the nitrogen-containing unsaturated compound include acrylonitrile, methacrylonitrile, vinyl pyridine, and N-vinyl pyrrolidone. These can be used alone or in combination of two or more.

  Examples of unsaturated amides include (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N, N-bis (2-hydroxyethyl) (meth) acrylamide, and the like. Can be mentioned. These can be used alone or in combination of two or more.

  Examples of the unsaturated acid anhydride include maleic anhydride and itaconic anhydride. These can be used alone or in combination of two or more.

  Examples of unsaturated sulfonic acids include allyl sulfonic acid, methallyl sulfonic acid, vinyl sulfonic acid, p-styrene sulfonic acid, acryloxybenzene sulfonic acid, methacryloxybenzene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, sulfone. Examples include ethyl acrylate. These can be used alone or in combination of two or more.

  Examples of esters of (meth) acrylic acid containing a polyalkylene oxide skeleton include polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polybutylene glycol mono (meth) acrylate, and polyethylene glycol polypropylene glycol mono (meth) acrylate. , Polyethylene glycol polybutylene glycol mono (meth) acrylate, polypropylene glycol polybutylene glycol mono (meth) acrylate, polyethylene glycol polypropylene glycol polybutylene glycol mono (meth) acrylate, etc., polyalkylene glycol (the number of alkylene glycol units is 2 or more ) Mono (meth) acrylic acid ester; methoxypolyethylene glycol mono (me ) Acrylate, methoxypolypropylene glycol mono (meth) acrylate, methoxypolybutylene glycol mono (meth) acrylate, ethoxypolyethylene glycol mono (meth) acrylate, ethoxypolypropylene glycol mono (meth) acrylate, ethoxypolybutylene glycol mono (meth) acrylate, etc. And mono (meth) acrylic acid ester of alkoxy polyalkylene glycol. These can be used alone or in combination of two or more.

  In addition, vinyl ester monomers such as vinyl acetate and vinyl propionate, and vinyl ether monomers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, and vinyl phenyl ether can be used.

The aqueous resin emulsion 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 aqueous resin emulsion of the present invention can be obtained by polymerizing the above monomer mixture by a known polymerization method. There is no particular limitation on the polymerization method, and a polymerization method using an aqueous medium such as emulsion polymerization, microemulsion polymerization, and miniemulsion polymerization may be employed, or obtained by performing solvent removal and neutralization phase inversion after solution polymerization. You can also.

When the water-based resin emulsion of the present invention is obtained by emulsion polymerization, an emulsifier may be used in order to stabilize the emulsion of the monomer mixture and generated 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. Anionic emulsifiers include dialkyl sulfosuccinates, alkylbenzene sulfonates, alkyl sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene alkyl diphenyl ether sulfates, polyoxyethylene alkyl ether sulfates, alkyl diphenyl ether disulfonates. , 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 0.01-50 mass parts normally per 100 mass parts of monomers, Preferably it is 0.05-20 mass parts, More preferably, it is 0. .1 to 10 parts by mass. When the amount of emulsifier used is small, the stability during production tends to be insufficient, and aggregates etc. are likely to be formed.On the other hand, when there is too much emulsifier, the emulsifier absorbs and absorbs water when using an adhesive product. Causes power loss.

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 performing 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. Also, peroxides, 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.

Moreover, in the said superposition | polymerization, a chain transfer agent can be used according to the use etc. of the polymer obtained.
As this chain transfer agent, a mercapto group-containing compound (ethanethiol, butanethiol, dodecanethiol, benzenethiol, toluenethiol, α-toluenethiol, phenethylmercaptan, mercaptoethanol, 3-mercaptopropanol, thioglycerin, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, α-mercaptoisobutyric acid, methyl mercaptopropionate, ethyl mercaptopropionate, thioacetic acid, thiomalic acid, thiosalicylic acid, octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, tert-tetradecyl mercaptan, etc.), xanthogen disulfide compounds (dimethyloxa) Tonogen disulfide, diethyl xanthogen disulfide, diisopropyl xanthogen disulfide, etc.), thiuram disulfide compounds (tetramethyl thiuram disulfide, tetraethyl thiuram disulfide, tetrabutyl thiuram disulfide, etc.), halogenated hydrocarbons (carbon tetrachloride, ethylene bromide, etc.), aromatic And hydrocarbon (pentaphenylethane, α-methylstyrene dimer, etc.). These can be used alone or in combination of two or more.

  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.

In the present invention, when adjusting the viscosity of the water-based resin emulsion, it is necessary to add the thickener divided into two or more times, preferably divided into three or more times, and divided into five or more times. It is more preferable. By adding the thickener separately, it is possible to obtain an aqueous resin emulsion composition in which the generation of aggregates is suppressed and the viscosity stability after adjustment is excellent. It is preferable to secure the time for adding the thickener added throughout the system. The specific time varies depending on the size of the reaction vessel and the stirring conditions, but it is preferable to secure 10 minutes or more, more preferably 30 minutes or more, and still more preferably 1 hour or more.
Moreover, the temperature at the time of adding and mixing a thickener is not specifically limited, However, The range of 10-80 degreeC is preferable and the range of 20-60 degreeC is more preferable.

Examples of the thickener include alkali-soluble thickeners, urethane-associative thickeners, water-soluble polymer thickeners, and natural thickeners such as cellulose and protein. Among them, since the alkali-soluble thickener generally tends to generate aggregates when added, the effect of the present invention is more remarkably exhibited.
In the present invention, the alkali-soluble thickener is treated as including an alkali swelling thickener.

  In this invention, it is preferable that pH at the time of adding a thickener is 7-10, and it is more preferable that it is 7.5-9. By setting the pH at the time of adding the thickener to 7 or more, the effect of suppressing the generation of aggregates and imparting viscosity stability can be obtained. On the other hand, the pH is preferably 10 or less from the viewpoint of safety during handling, odor, and the like.

Alkali-soluble thickeners are mainly composed of a high molecular weight polymer with many carboxyl groups and other acid groups introduced, and show a thickening effect by adjusting the pH from neutral to alkaline with an alkaline agent. To do. However, it was common knowledge to adjust the pH of the emulsion after addition of the thickener to the neutral to alkaline region, but by adjusting the pH at the time of addition to the neutral to alkaline region, suppression of aggregate generation and viscosity It has not been known about the point that the effect of stability is obtained.
As described above, since an alkali-soluble thickener has many acid groups introduced therein, the pH of the system is usually lowered by addition. If the pH at the time of adding a thickener is low, there may be cases where aggregates are generated even when the pH is adjusted to a neutral to alkaline region after adding a specified amount of thickener, or the viscosity stability is not sufficient. It is done. It is effective not to be after the thickener addition but to avoid the above problems by setting the pH at the time of addition to 7-10.

  The addition amount of the thickener is appropriately adjusted according to the types of the base emulsion and the thickener, and the target viscosity, but is 0.1 to 10 parts by mass with respect to 100 parts by mass of the solid content in the aqueous resin emulsion. It is preferable to use 0.1 to 5 parts by mass.

  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, cross-linking agents and other general additives may be added.

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 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 stability 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 was measured on the day of the adjustment and after a certain period of time under the condition of 25 ° C., and the smaller the viscosity change, the better the viscosity stability.

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

d) Aggregate amount 500 g of each emulsion composition after viscosity adjustment was filtered through 200 mesh polyethylene, and the ratio of aggregates was calculated from the weight of the filtration residue remaining on the net.

Production Example 1
In a reaction vessel equipped with a stirrer, a reflux condenser, a dropping tank and a thermometer, 40 parts of ion-exchanged water was charged and heated to 80 ° C. with stirring. In the dropping tank, 28 parts of ion-exchanged water, 2.4 parts of polyoxyethylene polycyclic phenyl ether sulfate ammonium salt (trade name “New Coal 707-SF” manufactured by Kao Corporation), sodium polyoxyalkylene disulfonate (manufactured by Kao Corporation) , 0.4 part by trade name "Newcol 240"), 90 parts by n-butyl acrylate (hereinafter referred to as "BA"), 10 parts by methyl acrylate (hereinafter referred to as "MA"), 2-hydroxyethyl acrylate ( Hereinafter, an emulsion was prepared by charging 1.5 parts of “HEA” and 1 part of methacrylic acid (hereinafter “MAA”) and stirring. While adding 1.6 parts of 25% aqueous solution of ammonium persulfate (hereinafter referred to as “APS”) as a polymerization initiator to the reaction vessel, the emulsion in the dropping tank obtained above was continuously put in the reaction vessel over 5 hours. After dropwise addition and emulsion polymerization, aging was further performed for 2 hours. At the start of aging, 1 part of a 10% APS aqueous solution was added, and the internal temperature of the reaction solution was maintained at 80 ° C. during the polymerization and aging period. After completion of the aging, the system was cooled and filtered through a 200 mesh polyethylene to obtain an aqueous resin emulsion A1 having a solid content of 59%.

Production Example 2
A reaction vessel similar to Production Example 1 was prepared, and 28 parts of ion-exchanged water, 2.4 parts of New Coal 707-SF, 0.4 parts of New Coal 240, 95 parts of BA, methyl methacrylate (hereinafter referred to as “MMA”) were prepared in the dropping tank. The emulsion was prepared by charging 5 parts, HEA 1.4 parts and MAA 1 part and stirring. A reaction vessel was charged with 24 parts of ion-exchanged water, 0.1 part of sodium polyoxyethylene alkyl ether sulfate (trade name “Latemul E-118BA” manufactured by Kao Corporation) and 3% equivalent of the emulsion in the dropping tank and stirred. The temperature was raised to 85 ° C. After 5 minutes, the rest of the emulsion in the dropping tank and 9.2 parts of 10% APS aqueous solution were continuously dropped into the reaction vessel over 4 hours to effect emulsion polymerization, and then aged for 2 hours. . At the start of aging, 0.15 parts of t-butyl hydroperoxide and 0.24 parts of sodium hyposulfite were added, and the internal temperature of the reaction liquid was maintained at 85 ° C. during the polymerization and aging period. After completion of aging, the system was cooled and filtered through 150 mesh polyethylene to obtain an aqueous resin emulsion A2 having a solid content of 57%.

Example 1
To 100 parts of the aqueous resin emulsion (A1) obtained in Production Example 1, 0.11 part of 25% aqueous ammonia solution was added to adjust the pH to 8.0, and then 0.34 part of 10% aqueous zinc acetate solution was added. And stirred. Alkali-soluble thickener (product name “Aron B-500”, manufactured by Toagosei Co., Ltd.) 0.15 parts is divided into 0.8 parts, 0.4 parts and 0.3 parts, and added at intervals of 2 hours. And stirred. During this time, a 25% aqueous ammonia solution was appropriately added to maintain the pH of the solution at 8.0. The obtained water-based resin emulsion composition had a solid content of 58% and a viscosity on the adjustment day of 11,500 mPa · s. Viscosity stability and aggregate amount are listed in Table 1.

Example 2
The pH at the time of addition of the thickener is as shown in Table 1, 1.4 parts of Aron B-500 is divided into 0.8 parts, 0.4 parts and 0.2 parts, and added at intervals of 2 hours. Stir. Otherwise, an aqueous resin emulsion composition was obtained in the same manner as in Example 1.
Table 1 shows the viscosity stability and the amount of aggregates of the obtained emulsion composition.

Example 3
The pH at the time of addition of the thickener is as shown in Table 1, 1.5 parts of Aron B-500 is 5 parts in 0.4 parts, 0.4 parts, 0.3 parts, 0.3 parts and 0.1 parts. Divided and added at 2-hour intervals and stirred. Otherwise, an aqueous resin emulsion composition was obtained in the same manner as in Example 1.
Table 1 shows the viscosity stability and the amount of aggregates of the obtained emulsion composition.

Example 4
The pH at the time of addition of the thickener is as shown in Table 1, 1.5 parts of Aron B-500 is 5 parts in 0.4 parts, 0.4 parts, 0.3 parts, 0.3 parts and 0.1 parts. Divided and added at 2-hour intervals and stirred. Otherwise, an aqueous resin emulsion composition was obtained in the same manner as in Example 1.
Table 1 shows the viscosity stability and the amount of aggregates of the obtained emulsion composition.

Example 5
The pH at the time of addition of the thickener is as shown in Table 1, 1.5 parts of Aron B-500 is 5 parts in 0.4 parts, 0.4 parts, 0.3 parts, 0.3 parts and 0.1 parts. Divided and added at 2-hour intervals and stirred. Otherwise, an aqueous resin emulsion composition was obtained in the same manner as in Example 1.
Table 1 shows the viscosity stability and the amount of aggregates of the obtained emulsion composition.

Comparative Example 1
The pH when the thickener was added was as shown in Table 1, and 1.6 parts of Aron B-500 was added all at once and stirred. Otherwise, an aqueous resin emulsion composition was obtained in the same manner as in Example 1.
Table 1 shows the viscosity stability and the amount of aggregates of the obtained emulsion composition.

Example 6
Table 10 shows the pH when a thickener was added after adding 10 parts of a tackifier resin emulsion (trade name “Superester E-865NT” manufactured by Arakawa Chemical Co., Ltd.) to the aqueous resin emulsion (A2) obtained in Production Example 2. Then, 1.5 parts of Aron B-500 was divided into three parts of 0.8 part, 0.4 part, and 0.3 part, added at intervals of 2 hours, and stirred. Otherwise, an aqueous resin emulsion composition was obtained in the same manner as in Example 1.
Table 2 shows the viscosity stability and the amount of aggregates of the obtained emulsion composition.

Comparative Example 2
The pH when the thickener was added was as shown in Table 2, and 1.5 parts of Aron B-500 was added all at once and stirred. Otherwise, an aqueous resin emulsion composition was obtained in the same manner as in Example 5.
Table 2 shows the viscosity stability and the amount of aggregates of the obtained emulsion composition.

The aqueous resin emulsion compositions obtained in Examples 1 to 6 were less likely to generate aggregates and had good viscosity stability.
On the other hand, in Comparative Examples 1 and 2 in which the thickener was added all at once, the amount of aggregates was large and the viscosity stability was not sufficient.

  According to the method for producing a water-based resin emulsion of the present invention, it is possible to obtain a water-based resin emulsion composition that suppresses generation of aggregates due to addition of a thickener and is excellent in viscosity stability. This is useful for water-based resin emulsion compositions used for various applications such as paints, adhesives, and pressure-sensitive adhesives.

Claims (3)

  A method for producing an aqueous resin emulsion composition, comprising adding and mixing a thickener to adjust the viscosity of an aqueous resin emulsion, and adding the thickener in two or more portions.   The method for producing an aqueous resin emulsion composition according to claim 1, wherein the thickener is an alkali-soluble thickener.   3. The method for producing an aqueous resin emulsion composition according to claim 1, wherein the pH when adding the thickener is 7 to 10. 5.