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ACRYLIC RESIN EMULSION, PRODUCTION METHOD THEREFOR, AND COATING COMPOSITION

20240174864 ยท 2024-05-30

    Inventors

    Cpc classification

    International classification

    Abstract

    [Purpose]

    An object of the present invention is to provide an acrylic resin emulsion that provides a coating film having transparency, water resistance, salt water resistance, and water repellency, a method for preparing the acrylic resin emulsion, and a coating composition.

    [Solution]

    An acrylic resin emulsion comprising: an acrylic resin, which is a polymerized product of (A) 20 to 80 parts by mass of a polymerizable group-containing triorganosilyl ester monomer, (B) 20 to 80 parts by mass of a (meth) acrylic acid alkyl ester monomer having no functional group, and (C) 0 to 60 parts by mass of a polymerizable group and functional group-containing monomer other than components (A) and (B), provided that a total mass of said components (A) to (C) is 100 parts by mass; and (D) 5 to 70 parts by mass of a polymeric emulsifier having a number average molecular weight of 1,000 or more, relative to the total 100 parts by mass of said components (A) to (C); and water.

    Claims

    1. An acrylic resin emulsion comprising: an acrylic resin, the acrylic resin being a polymerized product of the following components (A) to (C), (A) 20 to 80 parts by mass of a polymerizable group-containing triorganosilyl ester monomer, (B) 20 to 80 parts by mass of a (meth)acrylic acid alkyl ester monomer having no functional group, and (C) 0 to 60 parts by mass of a polymerizable group and functional group-containing monomer other than components (A) and (B), provided that a total mass of said components (A) to (C) is 100 parts by mass; and (D) 5 to 70 parts by mass of a polymeric emulsifier having a number average molecular weight of 1,000 or more, relative to the total 100 parts by mass of said components (A) to (C); and water.

    2. The acrylic resin emulsion according to claim 1, wherein component (A) is represented by the following general formula (I), ##STR00004## wherein R.sup.1 is a monovalent organic group having 2 to 24 carbon atoms and a polymerizable unsaturated double bond, and which may have a hetero atom; R.sup.2 to R.sup.4 are, independently of each other, a monovalent linear or branched hydrocarbon group having 3 to 10 carbon atoms, or a monovalent cyclic hydrocarbon group having 3 to 10 carbon atoms.

    3. The acrylic resin emulsion according to claim 1, wherein component (D) has a number average molecular weight of 3,000 to 200,000.

    4. The acrylic resin emulsion according to claim 1, wherein component (D) is one or more polymeric emulsifier selected from the group consisting of a carboxyl group-containing (co)polymer or a salt thereof, a carboxylic acid ester-containing (co)polymer, and a urethane resin.

    5. The acrylic resin emulsion according to claim 4, wherein component (D) is one or more polymeric emulsifier selected from the group consisting of a poly(meth)acrylic acid, a poly(meth)acrylic acid salt, a poly(meth)acrylic acid ester, a styrene-(meth)acrylic acid copolymer, a styrene-(meth)acrylic acid salt copolymer, a styrene-(meth)acrylic acid ester copolymer, and a polyurethane resin.

    6. The acrylic resin emulsion according to claim 1, wherein the acrylic resin emulsion has a minimum film forming temperature (MFT) of 0 to 50? C.

    7. The acrylic resin emulsion according to claim 1, wherein component (B) is a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 10 carbon atoms.

    8. A coating composition comprising the acrylic resin emulsion according to claim 1.

    9. A method for preparing an acrylic resin emulsion, wherein the method comprises the steps of emulsifying and polymerizing (A) a polymerizable group-containing triorganosilyl ester monomer and (B) a (meth)acrylic acid alkyl ester monomer having no functional group, and optional (C) a polymerizable group and functional group-containing monomer other than components (A) and (B); in the presence of 5 to 70 parts by mass of (D) a polymeric emulsifier having a number average molecular weight of 1,000 or more, relative to the total 100 parts by mass of said components (A) to (C), to obtain the acrylic resin emulsion.

    10. The method according to claim 9, wherein component (D) has a number average molecular weight of 3,000 to 200,000.

    11. The method according to claim 9, wherein component (D) is one or more polymeric emulsifier selected from the group consisting of a carboxyl group-containing (co)polymer or a salt thereof, a carboxylic acid ester-containing (co)polymer, and a urethane resin.

    12. The method according to claim 11, wherein component (D) is one or more polymeric emulsifier selected from the group consisting of a poly(meth)acrylic acid, a poly(meth)acrylic acid salt, a poly(meth)acrylic acid ester, a styrene-(meth)acrylic acid copolymer, a styrene-(meth)acrylic acid salt copolymer, a styrene-(meth)acrylic acid ester copolymer, and a polyurethane resin.

    13. The method according to claim 9, wherein component (A) is represented by the following general formula (I): ##STR00005## wherein R.sup.1 is a monovalent organic group having 2 to 24 carbon atoms and having a polymerizable unsaturated double bond, and which may have a hetero atom, R.sup.2 to R.sup.4 are, independently of each other, a monovalent linear or branched hydrocarbon group having 3 to 10 carbon atoms, or a monovalent cyclic hydrocarbon group having 3 to 10 carbon atoms.

    14. The method according to claim 9, wherein the acrylic resin emulsion has a minimum film forming temperature (MFT) of 0 to 50? C.

    15. The method according to claim 9, wherein component (B) is a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 10 carbon atoms.

    16. The acrylic resin emulsion according to claim 2, wherein component (D) has a number average molecular weight of 3,000 to 200,000.

    17. The acrylic resin emulsion according to claim 2, wherein component (D) is one or more polymeric emulsifier selected from the group consisting of a carboxyl group-containing (co)polymer or a salt thereof, a carboxylic acid ester-containing (co)polymer, and a urethane resin.

    18. The acrylic resin emulsion according to claim 3, wherein component (D) is one or more polymeric emulsifier selected from the group consisting of a carboxyl group-containing (co)polymer or a salt thereof, a carboxylic acid ester-containing (co)polymer, and a urethane resin.

    19. The method according to claim 10, wherein component (D) is one or more polymeric emulsifier selected from the group consisting of a carboxyl group-containing (co)polymer or a salt thereof, a carboxylic acid ester-containing (co)polymer, and a urethane resin.

    20. The method according to claim 10, wherein component (A) is represented by the following general formula (I): ##STR00006## wherein R.sup.1 is a monovalent organic group having 2 to 24 carbon atoms and having a polymerizable unsaturated double bond, and which may have a hetero atom, R.sup.2 to R.sup.4 are, independently of each other, a monovalent linear or branched hydrocarbon group having 3 to 10 carbon atoms, or a monovalent cyclic hydrocarbon group having 3 to 10 carbon atoms.

    Description

    EXAMPLES

    [0080] The present invention will be explained below in further detail with reference to a series of the Examples and the Comparative Examples, though the present invention is in no way limited by these Examples. In the following Examples, part and % represent part by mass and mass, respectively.

    [Acrylic Resin Emulsion]

    Example 1

    [0081] To a 2 L glass flask equipped with a stirring apparatus, a thermometer and a reflux condenser, 770 g of ion exchanged water, 2 g of sodium carbonate, and 630 g of JDX-6500 (polyacrylic acid oligomer) having a number average molecular weight of 10000 and a non-volatile content of 30% were added. The air in the vessel was purged with nitrogen, and the inner solution was heated while being stirred with a stirrer until the temperature of the inner solution reached 60? C. With the temperature of the inner solution maintained at 60? C.?1? C., a mixture of 70 g of 2-ethylhexyl acrylate (2-EHA), 87.5 g of methoxyethyl acrylate (MEA), and 192.5 g of triisopropylsilyl methacrylate (TIPSMA) was added dropwise over a period of 3 hours using a dropping funnel under a nitrogen stream, and while doing so, 1 g of ammonium persulfate (APS) dissolved in 45 g of ion exchanged water was added dropwise over a period of 4 hours to emulsify and polymerize the afore-mentioned mixture. After the reaction completed, the resultant was cooled to 40? C. or lower and dried at 105? C. for 1 hour, then a milky-white acrylic resin emulsion having a non-volatile content (solid content) of 31% was obtained.

    Example 2

    [0082] To a 2 L glass flask equipped with a stirring apparatus, a thermometer, and a reflux condenser, 770 g of ion exchanged water, 2 g of sodium carbonate, and 291.5 g of JDX-6500 (polyacrylic acid oligomer) having a number average molecular weight of 10000 and a non-volatile content of 30% were added. The air in the vessel was purged with nitrogen, and the inner solution was heated while being stirred with a stirrer until the temperature of the inner solution reached 60? C. With the temperature of the inner solution maintained at 60? C.?1? C., a mixture of 87.5 g of methylbutyl acrylate (BA), 70 g of methoxyethyl acrylate (MEA), and 192.5 g of triisopropylsilyl methacrylate (TIPSMA) was added dropwise over a period of 3 hours using a dropping funnel under a nitrogen stream, and while doing so, 1 g of ammonium persulfate (APS) dissolved in 45 g of ion exchanged water was added dropwise over a period of 4 hours to emulsify and polymerize the afore-mentioned mixture. After the reaction completed, the resultant was cooled to 40? C. or lower and dried at 105? C. for 1 hour, then a milky-white acrylic resin emulsion having a non-volatile content (solid content) of 29% was obtained.

    Example 3

    [0083] To a 2 L glass flask equipped with a stirring apparatus, a thermometer, and a reflux condenser, 770 g of ion exchanged water, 2 g of sodium carbonate, and 630 g of JDX-6500 (polyacrylic acid oligomer) having a number average molecular weight of 10000 and a non-volatile content of 30% were added. The air in the vessel was purged with nitrogen, and the inner solution was heated while being stirred with a stirrer until the temperature of the inner solution reached 60? C. With the temperature of the inner solution maintained at 60? C.?1? C., a mixture of 87.5 g of 2-ethylhexyl acrylate (2-EHA) and 262.5 g of triisopropylsilyl methacrylate (TIPSMA) was added dropwise over a period of 3 hours using a dropping funnel under a nitrogen stream, and while doing so, 1 g of ammonium persulfate (APS) dissolved in 45 g of ion exchanged water was added dropwise over a period of 4 hours to emulsify and polymerize the afore-mentioned mixture. After the reaction completed, the resultant was cooled to 40? C. or lower and dried at 105? C. for 1 hour, then a milky-white acrylic resin emulsion having a non-volatile content (solid content) of 30% was obtained.

    Example 4

    [0084] To a 2 L glass flask equipped with a stirring apparatus, a thermometer, and a reflux condenser, 770 g of ion exchanged water, 2 g of sodium carbonate, and 630 g of JDX-6500 (polyacrylic acid oligomer) having a number average molecular weight of 10000 and a non-volatile content of 30% were added. The air in the vessel was purged with nitrogen, and the inner solution was heated while being stirred with a stirrer until the temperature of the inner solution reached 60? C. With the temperature of the inner solution maintained at 60? C.?1?C, a mixture of 262.5 g of 2-ethylhexyl acrylate (2-EHA) and 87.5 g of triisopropylsilyl methacrylate (TIPSMA) was added dropwise over a period of 3 hours using a dropping funnel under a nitrogen stream, and while doing so, 1 g of ammonium persulfate (APS) dissolved in 45 g of ion exchanged water was added dropwise over a period of 4 hours to emulsify and polymerize the afore-mentioned mixture. After the reaction completed, the resultant was cooled to 40? C. or lower and dried at 105? C. for 1 hour, then a milky-white emulsion having a non-volatile content (solid content) of 30% was obtained.

    Example 5

    [0085] To a 2 L glass flask equipped with a stirring apparatus, a thermometer, and a reflux condenser, 770 g of ion exchanged water, 2 g of sodium carbonate, and 630 g of WLS-213 (urethane resin) having a number average molecular weight of 25000 and a non-volatile content of 30% were added. The air in the vessel was purged with nitrogen, and the inner solution was heated while being stirred with a stirrer until the temperature of the inner solution reached 60? C. With the temperature of the inner solution maintained at 60? C.?1? C., a mixture of 70 g of 2-ethylhexyl acrylate (2-EHA), 87.5 g of methoxyethyl acrylate (MEA), and 192.5 g of triisopropylsilyl methacrylate (TIPSMA) was added dropwise over a period of 3 hours using a dropping funnel under a nitrogen stream, and while doing so, 1 g of ammonium persulfate (APS) dissolved in 45 g of ion exchanged water was added dropwise over a period of 4 hours to emulsify and polymerize the afore-mentioned mixture.

    [0086] After the reaction completed, the resultant was cooled to 40? C. or lower and dried at 105? C. for 1 hour, then a milky-white emulsion having a non-volatile content (solid content) of 30% was obtained.

    Comparative Example 1

    [0087] To a 2 L glass flask equipped with a stirring apparatus, a thermometer, and a reflux condenser, 770 g of ion exchanged water, 2 g of sodium carbonate, and 630 g of JDX-6500 (polyacrylic acid oligomer) having a number average molecular weight of 10000 and a non-volatile content of 30% were added. The air in the vessel was purged with nitrogen, and the inner solution was heated while being stirred with a stirrer until the temperature of the inner solution reached 60? C. With the temperature of the inner solution maintained at 60? C.?1? C., 350 g of methyl methacrylate was added dropwise over a period of 3 hours using a dropping funnel under a nitrogen stream, and while doing so, 1 g of ammonium persulfate (APS) dissolved in 45 g of ion exchanged water was added dropwise over a period of 4 hours to emulsify and polymerize the afore-mentioned mixture. After the reaction completed, the resultant was cooled to 40? C. or lower and dried at 105? C. for 1 hour, then a milky-white emulsion having a non-volatile content (solid content) of 30% was obtained.

    Comparative Example 2

    [0088] In a 3 L polymerization vessel equipped with a stirrer, a condenser, a thermometer, and a nitrogen gas inlet port, 500 g of ion exchanged water was placed and after purging the air with nitrogen gas for 15 minutes, the temperature was raised to 70? C. Next, in another vessel, 70 g of 2-ethylhexyl acrylate (2-EHA), 87.5 g of methoxyethyl acrylate (MEA), 192.5 g of triisopropylsilyl methacrylate (TIPSMA), 3 g of SANMORIN OT-70 (produced by Kao Corporation), 16 g of NOIGEN XL-41 (produced by DKS), 28 g of NOIGEN XL-400 (produced by DKS), and 400 g of ion exchanged water were mixed and emulsified with a homogenizer to obtain an emulsified liquid, and the emulsified liquid and a mixture of 3 g of potassium persulfate and 100 g of ion exchanged water were separately and uniformly added dropwise to the afore-mentioned polymerization vessel over a period of 4 hours while being stirred. Furthermore, the resultant was reacted at 70? C. for 2 hours to complete polymerization. After cooling, 25% ammonia water was added to adjust the pH to 7. The obtained synthetic resin emulsion had a solid content of 40.4%.

    Comparative Example 3

    [0089] To a 2 L glass flask equipped with a stirring apparatus, a thermometer, and a reflux condenser, 770 g of ion exchanged water, 2 g of sodium carbonate, and 630 g of JDX-6500 (polyacrylic acid oligomer) having a number average molecular weight of 10000 and a non-volatile content of 30% were added. The air in the vessel was purged with nitrogen, and the inner solution was heated while being stirred with a stirrer until the temperature of the inner solution reached 60? C. With the temperature of the inner solution maintained at 60? C.?1?C, a mixture of 192.5 g of methyl methacrylate, 140 g of methoxyethyl acrylate (MEA), and 17.5 g of triisopropylsilyl methacrylate (TIPSMA) was added dropwise over a period of 3 hours using a dropping funnel under a nitrogen stream, and while doing so, 1 g of ammonium persulfate (APS) dissolved in 45 g of ion exchanged water was added dropwise over a period of 4 hours to emulsify and polymerize the afore-mentioned mixture. After the reaction completed, the resultant was cooled to 40? C. or lower and dried at 105? C. for 1 hour, then a milky-white emulsion having a non-volatile content (solid content) of 29% was obtained.

    Comparative Example 4

    [0090] To a 2 L glass flask equipped with a stirring apparatus, a thermometer, and a reflux condenser, 770 g of ion exchanged water, 2 g of sodium carbonate, and 933 g of JDX-6500 (polyacrylic acid oligomer) having a number average molecular weight of 10000 and a non-volatile content of 30% were added. The air in the vessel was purged with nitrogen, and the inner solution was heated while being stirred with a stirrer until the temperature of the inner solution reached 60? C. With the temperature of the inner solution maintained at 60? C.?1? C., 350 g of triisopropylsilyl methacrylate (TIPSMA) was added dropwise over a period of 3 hours using a dropping funnel under a nitrogen stream, and while doing so, 1 g of ammonium persulfate (APS) dissolved in 45 g of ion exchanged water was added dropwise over a period of 4 hours to emulsify and polymerize the triisopropylsilyl methacrylate. After the reaction completed, the resultant was cooled to 40? C. or lower and dried at 105? C. for 1 hour, then a milky-white emulsion having a non-volatile content (solid content) of 29% was obtained.

    <Measuring Method of Solid Content>

    [0091] About 1 g of the resin emulsion (sample) of each

    [0092] Example was placed in an aluminum foil dish and accurately weighed, placed in a dryer kept at about 105? C., heated for 1 hour, taken out from the dryer, and allowed to cool in a desiccator, then the weight of the sample after drying was measured. An evaporation residue was calculated by the following formula.

    [00001] R = T - L W - L ? 100 [0093] R: Evaporation residue (%) [0094] W: Mass of the aluminum foil dish including the sample before drying (g) [0095] L: Mass of the aluminum foil dish (g) [0096] T: Mass of the aluminum foil dish including the sample after drying (g) [0097] Dimensions of the aluminum foil dish: 70 ??12 h (mm)
    <Measuring Method of pH>

    [0098] The pH of each emulsion was measured at 25? C. by a pH meter according to JIS Z8802 (methods for determination of pH).

    <Measuring Method of Minimum Film Forming Temperature (MFT)>

    [0099] The minimum film forming temperature (MFT) of each emulsion was measured by a method according to JIS K-6828-2. Specifically, a simplified film formation temperature measuring apparatus (produced by Imoto machinery Co., LTD.), in which a heating source and a cooling source were installed at a certain distance from one another, was used. 1 Milliliter of the emulsion was applied on an aluminum foil, and the condition of the coating film was observed after 2 hours with aforesaid apparatus. Then, the emulsion was dried under a temperature gradient, and a boundary temperature between a transparent portion where a film was formed and a portion where a film was not formed was measured and determined as the minimum film forming temperature (MFT, ? C.).

    <Measuring Method of Average Particle Diameter of Emulsion Particles>

    [0100] The afore-mentioned obtained emulsions were further diluted with ion exchanged water to make solutions having a solid content of 0.5 to 2%, then the particle diameters of the emulsions were measured by the dynamic light scattering method with an FPAR-1000 produced by Otsuka Electronics Co. Ltd.

    <Evaluation of Preservation Stability>

    [0101] The emulsions were stored at room temperature (25? C.) for three months. The average particle diameters of the emulsions after storage were measured by the afore-mentioned method. Emulsions having a particle diameter that did not increase in a range exceeding 20% relative to the emulsion right after production were evaluated as good.

    <Film Forming Method>

    [0102] An epoxy resin-based rust-proofing coating material (BANNOH 500S, produced by Chugoku Marine Paints, Ltd.) was coated on a steel plate (produced by Nippon Test panel Co., Ltd., with both surfaces of SPHC undergoing sandblasting treatment) with a brush so that a thickness of a dried film became 100 ?m. After drying, an emulsion was coated on the film with a brush so that a thickness of a dried film became 100 ?m, and the film was dried at room temperature to make a coating film sample.

    <Measurement of Haze Value>

    [0103] An emulsion was applied on a glass slide (haze value 0.70%) so that a thickness of a dried film became about 7 ?m, then the film was dried at room temperature to form a coating film by a bar coater No. 10. The haze value of the glass slide having the afore-mentioned coating film was measured with a Haze Meter NDH7000 (trade name, produced by NIPPON DENSHOKU INDUSTRIES, Co., Ltd.) .

    <Measurement of Water Contact Angle>

    [0104] A contact angle 30 seconds after a 0.2 ?L water droplet was added dropwise to the above-described coating film sample was measured with an automatic Contact Angle Meter DCA-VZ produced by Kyowa Interface Science Co., Ltd.

    <Salt Water Resistance>

    [0105] A solution of sodium chloride dissolved in ion exchanged water to be 3.5% was assumed as a sea water. The above-described coating film sample was dipped in the solution for several days, then the condition of the coating film was observed visually. Then, the condition was observed over time, and the coating film which occurred no whitening, peeling, or cracking was evaluated as having no problem. At the stage where a failure in the film, such as whitening, peeling, or cracking, was observed, the observation was stopped, and that point was determined to be the ending point. Table 1 shows the number of days until each ending point.

    TABLE-US-00001 TABLE 1 Example Comparative Example 1 2 3 4 5 1 2 3 4 5 Composition, (A)TIPSMA 55 55 75 25 55 55 5 100 part by (B)MMA 100 55 mass (B)BA 45 (B)2-EHA 20 25 75 20 20 (C)MEA 25 25 25 40 (D)JDX- 54 25 54 54 54 54 80 100 6500, Solid content (D)WLS- 54 213, Solid content SANMORIN 0.9 OT-70 NOIGEN 4.6 XL-41 NOIGEN 8.0 XL-400D Solid 31 29 30 30 31 30 40 29 29 30 content, % Evaluation pH 6.7 6.7 6.7 6.6 6.7 7.9 6.5 6.3 6.7 7.7 MFT, ? C. 17 11 20 10 12 >60 <10 30 >60 >60 Average 240 190 300 170 110 50 220 100 1100 30 particle diameter, nm Average 250 200 300 180 110 300 230 110 1100 30 particle diameter after 3 months, nm Preservation Good Good Good Good Good Poor Good Poor Good Good stability Water contact 86 84 87 85 85 91 75 89.7 The 83 angle, ? film Haze 1.1 1.0 1.1 1.0 1.2 95 2.5 1.0 was 1.1 value, % cracked Salt water 30 days 30 days 30 days 30 days 30 days 1 day 1 day 3 days 7 days resistance or more or more or more or more or more TIPSMA: Triisopropylsilyl methacrylate, produced by Shin-etsu chemical co. ltd. MMA: Methyl methacrylate BA: Butyl acrylate 2-EHA: 2-ethylhexyl acrylate MEA: Methoxyethyl acrylate JDX-6500: Polyacrylic acid salt-based oligomer having a number average molecular weight of 10000, produced by BASF WLS-213: HYDRAN WLS-213 aqueous polyurethane resin having a number average molecular weight of 25000, produced by DIC Corporation

    Example 6

    [0106] Parts of ion exchanged water; 2 parts of BYK-190 (wetting dispersant, produced by BYK-Chemie) ; 20 parts of titanium oxide (TIPAQUE CR-95, produced by ISHIHARA SANGYO KAISHA, LTD.) having an average particle diameter of 0.28 ?m and being rutile type titanium oxide; and a total 100 parts of Talc MS produced by NIPPON TALC CO., LTD. and glass beads having a diameter of 1 mm were dispersed with a homogenizing disperser at a rotation speed of 3000 rpm for 60 minutes, then filtered through a 100-mesh metal screen to prepare a white paste. In the white paste, 371 parts of the emulsion obtained in Example 1 was added to obtain a coating composition.

    Examples 7 to 10, Comparative Examples 6 to 9

    [0107] The above-described procedure of Example 6 was repeated to obtain coating compositions, except that the compositions of the emulsions were changed to those in Table 2 below.

    <Film Forming Method>

    [0108] An epoxy resin-based rust-proofing coating material (BANNOH 500S, produced by Chugoku Marine Paints, Ltd.) was coated on a steel plate (produced by Nippon Test panel Co., Ltd., with both surfaces of SPHC undergoing sandblasting treatment) with a brush so that a thickness of a dried film became 100 ?m. After drying, the above-described coating composition was coated on the coating film with a brush so that a thickness of a dried film became 100 ?m, and the film was dried at room temperature to obtain a coating film sample.

    [0109] Water contact angle and salt water resistance of each coating film sample were evaluated by the above-described methods. The results are shown in Table 2.

    TABLE-US-00002 TABLE 2 Example Comparative Example Part by mass 6 7 8 9 10 6 7 8 9 Emulsion Example 1 371 Example 2 371 Example 3 371 Example 4 371 Example 5 371 Comparative 371 Example 1 Comparative 278 Example 2 Comparative 371 Example 3 Comparative 371 Example 5 Talc 5 5 5 5 5 5 5 5 5 Titanium oxide 20 20 20 20 20 20 20 20 20 BYK-190 2 2 2 2 2 2 2 2 2 Ion exchanged 25 25 25 25 25 25 118 25 25 water Evaluation Solid 32 32 33 32 32 32 33 32 32 Content, % Water contact 78 76 76 73 75 75 69 72 75 angle, ? Salt water 30 days 30 days 30 days 30 days 30 days 3 days 1 day 3 days 7 days resistance or more or more or more or more or more

    [0110] As shown in Tables 1 and 2, the acrylic resin emulsion of the present invention provides a coating film having transparency, water resistance, salt water resistance and water repellency and, further, also has excellent long-term preservation stability. Additionally, since the acrylic resin emulsion of the present invention has a minimum film forming temperature (MFT) of 50? C. or lower, it is possible to favorably form a film even at room temperature.