JPH1149831A - Additive for aqueous coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an additive for improving fluidity and coating properties of a coating material for a coated paper and for regulating water retainability by including an emulsion of an acrylic acid or methacrylic acid copolymer obtained by using a specific monoethylenic unsaturated monomer as a constitutional monomer. SOLUTION: This additive comprises an emulsion of an acrylic acid or methacrylic acid copolymer obtained by using (A) 20-70 pts.wt. acrylic acid or methacrylic acid, (B) 0.5-60 pts.wt. monoethylenic unsaturated monomer of formulas I [R<1> is a 5-20C alkyl; R<2> is CH3 or H; X is H, SO3 NH4 or SO3 Na, preferably SO3 NH4 ; (n) is 5-50, preferably 10-20] or II [(m) is 10-40, preferably 10-20], and preferably (C) 20-79.5 pts.wt. monoethylenic unsaturated monomer without the components A and B [e.g. an alkyl ester of (meth)acrylic acid] as constitutional monomers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous paint additive comprising a specific copolymer emulsion.
In particular, it relates to additives for water-based coated paper coatings, especially additives used to improve fluidity and coatability of coated paper coatings and to control water retention. Belong to.

[0002]

2. Description of the Related Art Coating paper coating materials are mainly composed of inorganic pigments and binders, and include pigments such as satin white, titanium oxide and aluminum hydroxide, and starch, starch oxide, phosphate ester as binders. Synthetic binders such as modified starch, natural polymers such as casein, styrene butadiene latex, carboxyl modified styrene butadiene latex, and vinyl acetate latex are used. In recent years, high quality performance has been required for coated paper coated with a coating for coated paper, and improvement in productivity of coated paper has also been required. However, the demand for high solid differentiation and high-speed coating properties has become remarkable. Paints for coated papers are applied under various shearing speeds using a coater such as a blade coater. Is insufficient, and the physical properties of the coated paper are reduced, that is, the smoothness, whiteness, and air permeability of the coated paper are reduced. As a method of improving such a defect, there is a method of adding a fluidity improver. As a fluidity improver, natural polymers such as sodium alginate and starch, and natural products such as carboxymethylcellulose, hydroxyethylcellulose and the like are synthesized. Aqueous acrylate solutions have been considered and used.
However, the above-mentioned fluidity improver is mainly a powdery product, and it takes time to dissolve when preparing an aqueous solution, and in the case of an aqueous solution such as polyacrylate, the viscosity of the liquid itself is considerably high, It has drawbacks on the handling surface. In particular, in the case of a natural product, there is a risk of spoilage and aging. Also,
In order to maintain the water retention of paper coatings, it is necessary to increase the amount of addition, and the viscosity of the coatings tends to be extremely high, and coating under high shear such as with a blade coater can be performed. It also had the disadvantage of disappearing. That is, it is difficult for the conventional fluidity improver to maintain high solid differentiation of the paint, and the fluidity and water retention under high shear are poor.
Phenomena, uneven coating and migration occur, which adversely affects the performance of the coated paper itself. Besides these
(Meth) acrylic acid (hereinafter acrylic and methacrylic (meth) acrylic and acrylate and methacrylate (meth)
There is also known an improvement method using an alkali-soluble thickener comprising an emulsion copolymer of (meth) acrylate, (meth) acrylate and ethyleneoxy-added (meth) acrylate (JP-A-1-47513). However,
The additive was also insufficient in terms of water retention.

[0003]

DISCLOSURE OF THE INVENTION The present inventors studied a method for satisfying the performance required for a coating material for coated paper without causing the above-mentioned problems, and studied a method for coating with a high solid content and a high solid content. Research was conducted to find additives that can provide coated paper coatings with good workability, especially additives that can be used to improve the fluidity and coatability of coated paper coatings and to control water retention. It is.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that an additive composed of a specific copolymer emulsion imparts good fluidity and water retention to an aqueous paint. The present invention was found to be an excellent additive particularly as a coating for coated paper, and completed the present invention.
That is, the present invention provides an aqueous paint additive comprising an acrylic acid or methacrylic acid copolymer emulsion containing a monoethylenically unsaturated monomer represented by the following chemical formula 1 or 2 as an essential constituent monomer. And additives for paints for coated paper.

[0005]

Embedded image

[0006]

Embedded image

In the chemical formulas 1 and 2, R ¹ is an alkyl group having 5 to 20 carbon atoms, R ² is CH ₃ or H, X is H, —SO ₃ NH ₄ or —SO ₃ Na, and n is 5-5
0 and m are integers of 10 to 40.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The copolymer constituting the emulsion in the present invention is a copolymer containing acrylic acid or methacrylic acid (hereinafter referred to as monomer A) as an essential constituent monomer. Monoethylenically unsaturated monomers represented by the chemical formulas 1 and 2 (hereinafter referred to as monomers B) are also essential constituent monomers. Among them, a copolymer containing methacrylic acid as a constituent monomer, that is, a methacrylic acid copolymer is preferable in the present invention. The monomer B is generally commercially available from an emulsifier manufacturer as an emulsifier, and in the present invention, it is used as a monomer constituting the copolymer. Examples of commercially available products include AQUALON RN-10, RN-30 and HS- manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
10, HS-20, Adekaria Soap NE-20, NE-40, SE-10, etc., manufactured by Asahi Denka Co., Ltd.
Among these, preferred is taken up in the present invention, X is -SO ₃ N
H ₄ a is n or m is of 10 to 20. As the copolymer of the present invention, monoethylenically unsaturated monomers other than the above monomers A and B (hereinafter referred to as monomer C)
However, it is preferable to use those used in combination according to the properties required for the aqueous paint additive. Examples of the monomer C include aromatic vinyl monomers such as styrene, α-methylstyrene and chlorostyrene, and acrylonitrile. And vinyl cyanide monomers such as methacrylonitrile, vinyl acetate, vinyl chloride, and alkyl (meth) acrylate. Among these, (meth) alkyl acrylate, when the emulsion copolymer alkali-soluble,
It is preferred because it has the highest alkali solubility. Examples of the alkyl (meth) acrylate include, for example, (meth) methyl acrylate, (meth) ethyl acrylate, (meth) butyl acrylate, (meth) isobutyl acrylate, (meth) tertiary butyl acrylate, ( 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, tetradecyl (meth) acrylate, hexadecyl (meth) acrylate, 2- (meth) acrylate Methoxyethyl, 3-methoxybutyl (meth) acrylate, among which more preferred are methyl (meth) acrylate, ethyl (meth) acrylate, (meth) butyl acrylate, (meth) acrylic acid
2-ethylhexyl, lauryl (meth) acrylate, (meth)
Tridecyl acrylate.

The composition ratio of the above-mentioned constituent monomers A, B and C is based on 100 parts by weight of the total of all the monomers.
Is preferably 20 to 70 parts by weight, monomer B is 0.5 to 60 parts by weight, and monomer C is 0 to 79.5 parts by weight. The amount of the monomer C is desirably 20 parts by weight or more. Monomer A
If the composition ratio is less than 20 parts by weight, the water retention of the coating material for paper coating tends to deteriorate, and if it exceeds 70 parts by weight, the viscosity of the coating material becomes high, and high-speed coating may not be possible. An undesired, particularly preferred ratio is 30 to 50 parts by weight. When acrylic acid is used as the monomer A, emulsion copolymerization with the monomer C may not proceed well. If the proportion of the monomer B is less than 0.5 parts by weight, the compatibility with the paper coating paint is not so good.
If the amount exceeds 60 parts by weight, foaming of the paper coating material is remarkable, and high-speed coating becomes difficult. The preferred composition ratio of the monomer B is 5 to 50 parts by weight. When the composition ratio of the monomer C is less than 20 parts by weight, the viscosity of the paper coating composition becomes high, and
When the amount is more than the weight part, the water retention may be deteriorated or the alkali solubility may not be completely obtained. The preferred composition ratio of the monomer C is 40 to 60 parts by weight.

The polymerization method for obtaining the above constituent monomers A and B or a copolymer comprising these and C is not particularly limited, and a general emulsion polymerization method can be used. For example, monomer A, monomer B, monomer C, and the like, and an emulsifier, a chain transfer agent for adjusting the molecular weight, a crosslinking agent, and the like, which are added as needed, are added to deionized water, dispersed, and then dispersed. A monomer emulsion is prepared, and an initiator and a monomer emulsion are continuously dropped into a polymerization vessel in separate lines.
What is necessary is just to carry out emulsion polymerization in the temperature range of ° C. Further, the monomer emulsion was charged all at once into a polymerization vessel, and then the temperature was lowered to 4%.
A polymerization method in which a polymerization initiator is continuously dropped while maintaining the temperature at 0 ° C to 100 ° C is also possible. In the present invention, since a monomer having a function as an emulsifier is used as the monomer B, it is not always necessary, but a general emulsifier other than the monomer B is used to stabilize the emulsion. It can also be said to be a preferable method. Common emulsifiers include nonionic and anionic emulsifiers,
Specifically, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene higher alcohol ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, sorbitan monolaurate, sorbitan Monostearate,
Sorbitan tristearate, sorbitan sesquiolate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan monooleate, Polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol distearate, polyethylene glycol trialkylnaphthalenesulfonic acid, dialkylsulfosuccinic acid, sodium alkyldiphenyl ether disulfonate, potassium alkyl phosphate, sodium polyoxyethylene lauryl ether sulfate , Sodium polyoxyethylene alkyl ether sulfate, polyoxyethylene Alkyl ether triethanolamine sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, sodium alkane sulfonate, sodium dodecylbenzene sulfonate, ammonium lauryl sulfate, sodium lauryl sulfate, potassium oleate soap, semi-hardened tallow fatty acid potassium soap, sodium stearate soap , Mixed fatty acid soda soap, lauryl phosphate,
Polyoxyethylene ether phosphate, polyoxyethylene alkyl ether phosphate, polyoxyethylene stearyl ether phosphate, polyoxyethylene oleyl ether phosphate, polyoxyethylene alkyl phenyl ether phosphate, polyoxyethylene dialkyl ether Phosphates and the like. Among them, preferred are sodium polyoxyethylene lauryl ether sulfate with addition of 2 to 20 mol of ethylene oxide, sodium polyoxyethylene nonyl phenyl ether sulfate with addition of 2 to 20 mol of ethylene oxide, and polyoxyethylene with addition of 2 to 20 mol of ethylene oxide. Ethylene alkyl ether phosphoric acid and its sodium salt, polyoxyethylene oleyl ether phosphate, polyoxyethylene nonyl phenyl ether phosphate, and polyoxyethylene dialkyl ether phosphate. The use ratio of the emulsifier is 0.5 based on 100 parts by weight of the total of the monomer components.
-20 parts by weight, preferably 3 to 10 parts. Examples of the chain transfer agent include dodecyl mercaptan, mercaptopropionic acid, normal octyl propionate with low odor, and normal dodecyl propionate. Examples of the initiator include radical polymerization initiators such as persulfates such as ammonium persulfate, sodium persulfate and potassium persulfate, and water-soluble azo compounds such as amidinopropane hydrochloride, and organic peroxides such as t-butyl hydroperoxide. Redox initiator of a substance and a reducing substance such as sodium sulfite.

The emulsion in the present invention is an emulsion of an acrylic acid or methacrylic acid copolymer and belongs to the category of an alkali-soluble emulsion, and is generally an alkali metal salt such as sodium hydroxide or potassium hydroxide. Aqueous liquid having a pH of 6 to 13 after neutralization with hydroxides or hydroxides of alkaline earth metal salts such as calcium hydroxide and magnesium hydroxide, aqueous ammonia and amines such as ethanolamine and triethanolamine. Is used as The emulsion of the present invention is used as an additive for water-based paints, and is suitable for improving the fluidity of water-soluble paints, especially paints for coated papers. It is also suitable for improving the properties. The aqueous paint additive comprising the specific emulsion of the present invention has the pH adjusted to the above-mentioned range as it is, and the unadjusted one is prepared by adding the above-mentioned alkali compound in advance when using the desired additive.
After adjusting the pH, it can be used by adding it to the coating or by adding an alkali compound after adding the coating to adjust the pH. The amount added at the time of use must be appropriately selected according to the type and performance of the paint to be added.
0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight,
More preferably, 0.1 to 3 parts by weight is added to the paint. If added in an amount of 10 parts by weight or more, the viscosity of the coating material will be remarkably increased, the flowability of the coating material will not be obtained, and coating under high shear may not be possible.

[0012]

The additive for a water-based paint comprising the specific copolymer emulsion of the present invention is used by being added to a water-based paint, especially a coated paper-based paint mainly containing a pigment and a binder.
The additive of the present invention does not need to be dissolved in water as in the case of a conventional powdery fluidity improver, and can improve fluidity and water retention by being directly added to a paint. In addition, coating with a coater such as a blade coater, roll coater, air knife coater, rod coater, etc. in the coating process, drying with a dryer such as an infrared dryer, drum dryer, or air conditioner dryer after coating, super calendar This does not cause a problem in calendaring or the like.

[0013]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples below, but the present invention is not limited to these examples. In the following, parts by weight and% by weight are simply referred to as parts or%, respectively. Example 1 120 parts of deionized water, 38 parts of methacrylic acid, 5 parts of polyoxyethylene propenyl nonyl phenyl ether with 10 moles of ethylene oxy unit added (in the above formula 1, R ¹ is a nonyl group, R ² is a methyl group, X Is H, Aqualon RN-10 manufactured by Daiichi Kogyo Seiyaku, ethyl acrylate 57
And 3 parts of sodium polyoxyethylene alkylphenyl ether sulfate are stirred and mixed to prepare a monomer emulsion. 85 parts of deionized water is charged into a 3 L four-necked round bottom flask equipped with a reflux tube, a thermometer, and a dropping funnel, and the internal temperature is raised to 90 ° C. After adding 3 parts of 0.016 parts of an aqueous solution of ammonium persulfate, 10 parts of the monomer emulsion prepared above was added, and when the internal temperature was raised to 85 ° C., the remaining monomer emulsion and 0.2 parts of 0.2 parts were added. 8 parts of an aqueous ammonium persulfate solution was continuously dropped for 2 hours while maintaining the internal temperature at 80 to 100 ° C. After dropping, aged for 1 hour,
After cooling, an additive A consisting of a milky white emulsion having a solid content of 30%, a viscosity of 9 mPa · S, was obtained. ○ Examples 2 to 4 120 parts of deionized water, 38 parts of methacrylic acid, α- [1-[(allyloxy) methyl] -2 (nonylphenoxy) ethyl] -ω-hydroxypolyoxyethylene with addition of 20 mol of ethyleneoxy units 5 parts (Adekaria Soap N manufactured by Asahi Denka, wherein R ¹ is a nonyl group, R ² is H and X is H
E-20), 57 parts of ethyl acrylate and 3 parts of sodium polyoxyethylene alkylphenyl ether sulfate were stirred and mixed to prepare a monomer emulsion. 85 parts of deionized water was charged into a 3 L four-necked round bottom flask equipped with a reflux tube, a thermometer, and a dropping funnel, and the internal temperature was raised to 90 ° C. After adding 3 parts of 0.016 parts of an aqueous solution of ammonium persulfate, 10 parts of the monomer emulsion prepared above was added, and when the internal temperature was raised to 85 ° C., the remaining monomer emulsion and 0.2 parts of 0.2 parts were added. 8 parts of an aqueous ammonium persulfate solution was continuously dropped for 2 hours while maintaining the internal temperature at 80 to 100 ° C. After completion of the dropwise addition, the mixture was aged for 1 hour, cooled, and then solidified at 30%.
%, A viscosity of 8 mPa · S, and an additive B as a milky white emulsion. Similarly, Additive C (Example 3) and Additive C (Example 4) shown in Table 1 were obtained. RN-30 in the table
Is a polyoxyethylene propenyl nonyl phenyl ether with addition of 30 moles of ethyleneoxy units (Aqualon RN-30 manufactured by Dai-ichi Kogyo Seiyaku, wherein R ¹ is a nonyl group, R ² is a methyl group, and X is H in the chemical formula 1), NE-40 Is α- [1-[(allyloxy) methyl] -2 (nonylphenoxy) ethyl] -ω-hydroxypolyoxyethylene to which 40 moles of ethyleneoxy units are added (wherein R ¹ is a nonyl group, R ² is H, X is H of Adeka Ria Soap NE-40) manufactured by Asahi Denka. ○ Example 5 120 parts of deionized water, 38 parts of methacrylic acid, and 5 parts of a polyoxyethylene propenyl phenyl ether sulfate ammonium salt with 10 mol of ethyleneoxy units added (in the above formula 1, R ¹ is a nonyl group and R ² is a methyl group , X was ammonium sulfate, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Aqualon HS-10) and 57 parts of ethyl acrylate were stirred and mixed to prepare a monomer emulsion. 85 parts of deionized water was charged into a 3 L four-necked round bottom flask equipped with a reflux tube, a thermometer, and a dropping funnel, and the internal temperature was raised to 90 ° C. 0.
After charging 3 parts of an aqueous solution of 016 parts of ammonium persulfate, 10 parts of the monomer emulsion prepared above was added, and when the internal temperature was raised to 85 ° C, the remaining monomer emulsion and 0.2 parts of ammonium persulfate were added. 8 parts of the aqueous solution was continuously dropped for 2 hours while maintaining the internal temperature at 80 to 100 ° C. After completion of the dropwise addition, the mixture was aged for 1 hour, and after cooling, an additive E which was a milky white emulsion having a solid content of 30%, a viscosity of 8 mPa · S, was obtained. ○ Examples 6 to 7 120 parts of deionized water, 50 parts of ethyl acrylate, α- [1-[(allyloxy) methyl] -2 (nonylphenoxy) ethyl] -ω-hydroxypolyoxy with addition of 10 mol of ethyleneoxy units Ethylene ammonium sulfate 5
(Wherein R ¹ is a nonyl group, R ² is H, X
Is Adekaria Soap SE made by Asahi Denka of ammonium sulfate.
10N), 45 parts of methacrylic acid, and 3 parts of sodium polyoxyethylene alkylphenyl ether sulfate were stirred and mixed to prepare a monomer emulsion. Reflux tube,
85 parts of deionized water is charged into a 3 L four-necked round bottom flask equipped with a thermometer and a dropping funnel, and the internal temperature is raised to 90 ° C. After charging 3 parts of an aqueous solution of 0.016 parts of ammonium persulfate, the monomer emulsion prepared above was added to 10 parts of an aqueous solution.
When the internal temperature rises to 85 ° C., the remaining monomer emulsion and 0.2 parts of an aqueous ammonium persulfate solution 8 are added.
While maintaining the internal temperature at 80 to 100 ° C., the mixture was continuously dropped for 2 hours. After completion of the dropwise addition, the mixture was aged for 1 hour, cooled, and then solidified at 30%.
%, A viscosity of 10 mPa · S and an additive F which was a milky white emulsion. Additive G (Example 7) was obtained according to the polymerization recipe of Example 6 with the composition shown in Table 1. In addition, HS-20 in the table
Is a polyoxyethylene propenyl nonyl phenyl ether sulfate ammonium having 20 moles of ethylene oxy units (R ¹ is a nonyl group, R ^1
2 is a methyl group and X is Aqualon HS-20, manufactured by Daiichi Kogyo Seiyaku, having ammonium sulfate ester.

Comparative Example 1 A monomer emulsion was prepared by stirring and mixing 120 parts of deionized water, 40 parts of methacrylic acid, 60 parts of ethyl acrylate, and 3 parts of sodium polyoxyethylene alkylphenyl ether sulfate. A 3 L four-necked round bottom flask equipped with a reflux tube, a thermometer, and a dropping funnel was charged with 85 deionized water.
The temperature of the part was increased to 90 ° C. Then, 3 parts of an aqueous solution of 0.016 parts of ammonium persulfate was charged, and then 10 parts of the monomer emulsion prepared above was added.
Once it has risen, the remaining monomer emulsion and 0.2
Of ammonium persulfate aqueous solution at an internal temperature of 80-100
The solution was continuously dropped for 2 hours while maintaining the temperature at ℃. After completion of the dropwise addition, the mixture was aged for 1 hour, and after cooling, an additive H as a milky white emulsion having a solid content of 30%, a viscosity of 9 mPa · S, was obtained. Comparative Example 2 A 5% aqueous solution of carboxymethyl cellulose (CMC) was prepared and used as additive I.

[0015]

[Table 1] * B-type viscometer manufactured by Tokyo Keiki Co., Ltd. Measured at 60 rpm and 25 ° C. ** Viscosity of 5% aqueous solution MAA; methacrylic acid EA; ethyl acrylate CMC; carboxymethyl cellulose

The performance of the additives of Examples and Comparative Examples was evaluated by the following methods. The results are shown in Table 2. (1) Formulation of coating for coated paper 70 parts of kaolin (UW-90 manufactured by Engelhard Co.), 30 parts of heavy calcium carbonate (Super 2000 manufactured by Maruo Calcium Co., Ltd.), 0.3 part of dispersant (T manufactured by Toagosei Co., Ltd.) -4
0), 5 parts of phosphoric acid-modified starch (MS-4 manufactured by Japan Food Processing Co., Ltd.)
600), 10 parts of SBR latex (JSR0668 manufactured by Nippon Synthetic Rubber Co., Ltd.), and 0.5 part of lubricant (Nopco 1097A manufactured by San Nopco, Inc.) were added in terms of solid content. The pH was adjusted to 9.0 with 0.1 to 0.3 parts of sodium to obtain a coating paper coating having a coating concentration of 60%. (2) Paint properties Low shear viscosity Measured at 25 rpm at 60 rpm with a B-type viscometer manufactured by Tokyo Keiki. High shear viscosity High shear viscometer manufactured by Kumagai Riki Kogyo, Bo at 8800 rpm
Measured at b-F. Water retention The amount of water in the paint absorbed by the filter paper was measured using an AA-GWR water retention tester manufactured by Kaltec Scientific. (3) Coated paper properties. The obtained coating composition was coated with Phoenix acidic woodfree paper at 64 g / m ^2.
The solution was coated on the top using a doctor blade No. 5 in an amount of 10 g / m ² , and dried at 150 ° C. for 30 seconds with a ventilation dryer. Then, at 70 ° C, linear pressure 70Kg / cm with super calender
After passing the paper twice, the humidity was adjusted and measured. Whiteness Measured using Technobright Micro TB-1C manufactured by Techinidyne Corporation. Air permeability, smoothness Measured by Oken type smoothness air permeability tester.

[0017]

[Table 2]

[0018]

The additive for water-based paint of the present invention does not significantly increase the viscosity under low shear, reduces the viscosity under high shear, and improves the water retention of the paint well. Things. The water-based paint additive of the present invention may be added to the coated paper paint as it is, and the pH may be adjusted with an alkali compound such as sodium hydroxide or an aqueous ammonia solution. Conventional fluidity improvers such as sodium alginate and Unlike natural products such as carboxymethylcellulose and hydroxyethylcellulose, no time is required for preparing an aqueous solution, the viscosity of the additive itself is low, and good handling properties are exhibited. In addition, there is no fear of decay or change over time. The additive of the present invention can impart not only excellent fluidity but also good water retention to a coated paper coating while maintaining a high solid content of the coating. In other words, even under high shear such as with a blade coater, the blade pressure does not rise, the coating can be performed without a streak phenomenon, even coating, the migration of the binder does not occur, and the coated paper can be formed. Good ones are obtained.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Minoru Atsuchi 1-1-1 Funamicho, Minato-ku, Nagoya-shi, Aichi Prefecture Inside Nagoya Research Institute, Toagosei Co., Ltd. (72) Kunihiko Mizutani Funamicho, Minato-ku, Nagoya-shi, Aichi No. 1, No. 1 Toagosei Co., Ltd. Nagoya Research Laboratory

Claims (3)

[Claims] An additive for an aqueous paint, comprising an acrylic acid or methacrylic acid copolymer emulsion containing a monoethylenically unsaturated monomer represented by the following chemical formula 1 or 2 as an essential constituent monomer. . Embedded image Embedded image However, in Chemical Formulas 1 and 2, R ¹ has 5 to 20 carbon atoms.
R ² is CH ₃ or H, X is H, —SO ₃ N
H ₄ or —SO ₃ Na, n is 5 to 50, m is 10 to
It is an integer of 40. 2. An aqueous paint obtained by adding the additive for aqueous paint according to claim 1. 3. The coating according to claim 2, wherein the water-based coating is a coating for coated paper.
A water-based paint as described.