Dispersant and aqueous coating composition

Abstract

The purpose of the present invention is to provide a dispersant which exhibits excellent dispersibility and in which the water resistance of a coating film obtained therefrom does not decrease even when added to an aqueous coating agent. The present invention is a dispersant characterized by comprising (A) a styrene-maleic acid organic ammonium salt copolymer and (B) an alkylene oxide (C2-4, addition mole number of 3-50 moles) adduct of at least one active hydrogen compound (C4-18) selected from the group consisting of alcohols, carboxylic acids, amines and amides, the active hydrogen compound having a branched alkyl chain having C4-18. The composition molar ratio (s: m) of styrene units (s) and ammonium maleate units (m) constituting the styrene-ammonium maleate copolymer is preferably from 80: 20 to 40: 60. The weight ratio (A: B) of the styrene-ammonium maleate copolymer (A) to the polyoxyalkylene compound (B) is preferably 10: 90 to 90: 10.

Description

Technical Field

[0001] The present invention relates to a dispersant and a water-based coating composition. Background Art

[0002] As a dispersant, there is known: "A mixture having a low volatile organic compound (VOC) content, comprising the following components:

[0003] I: 10 to 80% by weight of a copolymer of at least one ethylenically unsaturated monomer containing a phenyl group and at least one α,β-unsaturated monocarboxylic acid and / or at least one α,β-unsaturated dicarboxylic acid and, if applicable, their derivatives, which is at least 50% chlorinated;

[0004] II: 1 to 30% by weight of a linear polyether, which is at least one water-soluble linear polyether containing terminal OH end groups and which is synthesized from ethylene oxide to a degree of at least 25 mol %;

[0005] III: 5 to 80% by weight of an esterification product of at least one esterification product of an aliphatic dicarboxylic acid and at least one water-soluble polyether of component II, preferably having a number-average molecular weight of ≤2000 g / mol, or a mixture of polyethers comprising at least one water-soluble polyether of component II, preferably having a number-average molecular weight of ≤2000 g / mol;

[0006] IV: 3 to 80% by weight of a star polymer, which is at least one star polymer obtainable by esterifying at least one aliphatic carboxylic acid having 3 to 5 carboxyl groups with at least one of the water-soluble polyethers of component II, preferably having a number average molecular weight of ≤2000 g / mol, or a mixture of polyethers containing at least one water-soluble polyether of component II, preferably having a number average molecular weight of ≤2000 g / mol,

[0007] The abovementioned % by weight of components I to IV must always add up to 100 % by weight, and the abovementioned % by weight of components I-IV are based in each case on the abovementioned total weight of components I-IV (claim 1)”;

[0008] “A mixture according to any one of claims 1 to 3 (claim 4), characterized in that component I is in the form of an alkali metal, alkaline earth metal or ammonium salt, preferably in the form of a sodium or potassium salt”;

[0009] "The mixture according to claim 5 (claim 6), characterized in that at least one monomer selected from styrene, benzyl (meth)acrylate and phenyl acrylate (the phenyl radical may be substituted 1 to 4 times depending on the circumstances), preferably substituted styrene depending on the circumstances, is used as the above-mentioned ethylenically unsaturated phenyl group-containing monomer";

[0010] "Mixture according to claim 5 or 6 (claim 7), characterized in that acrylic acid or methacrylic acid is used in the form of an α,β-unsaturated monocarboxylic acid and at least one dicarboxylic acid (selected from maleic acid, fumaric acid and itaconic acid and / or maleic anhydride) and, if appropriate, in the form of their respective derivatives, preferably in the form of esters or amides, and at least one C1-C6 alkyl acrylate and / or C1-C6 alkyl methacrylate is used in the form of an α,β-unsaturated dicarboxylic acid and / or its cyclic anhydride";

[0011] And "according to the use described in claim 21 or 22 (claim 23), it is used for dispersing a pigment" (Patent Document 1).

[0012] Prior art literature

[0013] Patent Literature

[0014] Patent Document 1: Japanese Patent Application Publication No. 2011-511142 (Pamphlet No. WO2009 / 098025) Summary of the invention

[0015] Problems to be solved by the invention

[0016] Conventional dispersants have problems in that the dispersibility of the pigment is sometimes insufficient and the water resistance of a coating film obtained from an aqueous coating composition to which the dispersant is added is reduced.

[0017] An object of the present invention is to provide a dispersant which exhibits excellent dispersibility and does not reduce the water resistance of a coating film obtained therefrom even when added to a water-based coating agent.

[0018] Means for solving problems

[0019] The dispersant of the present invention is characterized in that it comprises a styrene-maleic acid organic ammonium salt copolymer (A) and an alkylene oxide (carbon number 2 to 4; addition mole number 3 to 50 mol) adduct (B) of at least one active hydrogen compound (carbon number 4 to 18) selected from alcohols, carboxylic acids, amines and amides,

[0020] The active hydrogen compound has a branched alkyl chain having 4 to 18 carbon atoms.

[0021] The water-based coating composition of the present invention is characterized in that it contains a water-based coating agent and the above-mentioned dispersant.

[0022] Effects of the Invention

[0023] The dispersant of the present invention exhibits excellent dispersibility and does not reduce the water resistance of a coating film obtained from an aqueous coating composition to which the dispersant is added.

[0024] Since the water-based coating composition of the present invention contains the above-mentioned dispersant, it exhibits excellent dispersibility and can obtain a coating film having excellent water resistance. DETAILED DESCRIPTION

[0025] <Styrene-maleic acid organic ammonium salt copolymer (A)>

[0026] The styrene-maleic acid organic ammonium salt copolymer (A) is not limited as long as it is a copolymer having styrene units (s) and maleic acid organic ammonium salt units (m) as constituent units, and a copolymer produced by a known method can be used. For example, a copolymer obtained by hydrolyzing a styrene-maleic anhydride copolymer and neutralizing it with an organic amine can be used.

[0027] Styrene-maleic anhydride copolymers can be produced by known methods or can be easily purchased from the market. Examples thereof include XIRANE 1000 (styrene-maleic anhydride resin, weight average molecular weight of 5000, 50 mol% styrene, 50 mol% maleic anhydride, POLYSCOPE POLYMERS BV), XIRANE 2000 (styrene-maleic anhydride resin, weight average molecular weight of 6500, 67 mol% styrene, 33 mol% maleic anhydride, POLYSCOPE POLYMERS BV), XIRANE 3000 (styrene-maleic anhydride resin, weight average molecular weight of 10000, 75 mol% styrene, 25 mol% maleic anhydride, POLYSCOPE POLYMERS BV), and XIRANE 4000 (styrene-maleic anhydride resin, weight average molecular weight of 10000, 80 mol% styrene, 20 mol% maleic anhydride, POLYSCOPE POLYMERS BV).

[0028] Examples of the organic amine include monoamines having 2 to 18 carbon atoms, such as primary amines (ethylamine, monoethanolamine, butylamine, propylamine, pentylamine, hexylamine, cyclohexylamine, aniline, benzylamine, 2-amino-2-methyl-1-propanol, oleylamine, etc.); secondary amines (diethylamine, methylethylamine, diethanolamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, methylhexylamine, dicyclohexylamine, etc.); and tertiary amines (triethylamine, triethanolamine, tripropylamine, dimethylpropylamine, tributylamine, tripentylamine, trihexylamine, dimethylcyclohexylamine, tricyclohexylamine, etc.).

[0029] The molar ratio (s:m) of the styrene unit (s) to the maleic acid organic ammonium salt unit (m) constituting the styrene-maleic acid organic ammonium salt copolymer is preferably 80:20 to 40:60, more preferably 70:30 to 45:55, and particularly preferably 67:33 to 50:50. Within this range, dispersibility and water resistance are further improved.

[0030] The weight average molecular weight (Mw) of the styrene-maleic acid organic ammonium salt copolymer (A) is preferably 3,000 to 20,000, more preferably 4,000 to 15,000, and particularly preferably 6,000 to 12,000. Within this range, dispersibility and water resistance become more favorable.

[0031] The weight average molecular weight (Mw) can be measured by gel permeation chromatography (GPC), for example, under the following conditions.

[0032] Measurement device: HLC-8420GPC (TOSOH Corporation, "HLC" is a registered trademark of the company.)

[0033] Chromatographic column: A column composed of TSKgel guard column α, TSKgel α6000, and TSKgel α4000 (TSKgel is a registered trademark of TOSOH Corporation) in series.

[0034] Detector: RI (differential refractometer)

[0035] Data processing: ECOSEC Elite-WS (TOSOH CORPORATION, "ECOSEC" is a registered trademark of the company.)

[0036] Column temperature 40℃

[0037] Solvent: methanol: ion exchange water: sodium acetate = 800: 1200: 15 (weight ratio)

[0038] Flow rate: 0.8ml / min

[0039] Standard material: TSKgel standard polyethylene oxide (TOSOH Corporation, "TSKgel" is a registered trademark of the company.)

[0040] Sample: 0.4 wt% eluent solution

[0041] <Alkylene oxide adduct of active hydrogen compound (B)>

[0042] The active hydrogen compound having 4 to 18 carbon atoms is not particularly limited as long as it is at least one selected from alcohols, carboxylic acids, amines and amides, has a branched alkyl group having 4 to 18 carbon atoms, and can chemically react with an alkylene oxide having 2 to 4 carbon atoms to form an alkylene oxide adduct of the active hydrogen compound.

[0043] Examples of the alcohol include branched monoalcohols having 4 to 18 carbon atoms, such as branched primary alcohols (2-methyl-1-propanol, 2-methyl-1-butanol, 2-methyl-1-pentanol, 3-methyl-1-pentanol, 3-ethyl-1-butanol, 3-methyl-1-butanol, 3,3-dimethyl-1-butanol, 2,3-dimethyl-1-butanol, 4,4-dimethyl-1-pentanol, 2,4,4-trimethyl-1-pentanol, 2-ethyl-1-hexanol, 2,2,4-trimethyl-1-hexanol, 3,5,5-trimethyl-1-hexanol, isononanol, isodecanol, 2-methyl-1-undecanol, 12-methyl-1-tridecanol) , isotridecanol, 2-hexyl-1-decanol, isohexadecanol, 2-octyl-1-decanol, 2-hexyl-1-undecanol, 2-hexyl-1-dodecanol, 2-(1,3,3-trimethylbutyl)-5,7,7-trimethyloctanol, 2,2,4,8,10,10-hexamethylundecan-5-ol and isooctadecanol, etc.); and branched secondary alcohols (2-pentanol, 7-tetradecanol, 3-methyl-2-butanol, 4-methyl-2-pentanol, 2,3-dimethyl-2-butanol, 2,2-dimethyl-3-pentanol, 2,2,4-trimethyl-2-pentanol and 7-ethyl-2-methyl-4-undecanol, etc.).

[0044] Examples of the carboxylic acid include branched monocarboxylic acids having 4 to 18 carbon atoms, such as 2,2-dimethylpropionic acid, 2-methylbutanoic acid, 4-methylpentanoic acid, 3,3-dimethylbutanoic acid, 2-methylhexanoic acid, 3,5,5-trimethylhexanoic acid, 2-ethylhexanoic acid, 2-methylpentadecanoic acid, and 2-methylheptadecanoic acid.

[0045] Examples of the amine include branched monoamines having 4 to 18 carbon atoms, such as branched primary amines (isobutylamine, isopentylamine, neopentylamine, and 2-methylbutylamine); and branched secondary amines (methylisobutylamine, methylisopentylamine, methylneopentylamine, and 2-methylbutylethylamine).

[0046] Examples of the amide include branched monoamides having 4 to 18 carbon atoms, such as 2,2-dimethylpropionic acid amide, isobutyric acid amide, 2-methylbutyric acid amide, 4-methylvaleric acid amide, 3,3-dimethylbutyric acid amide, 2-methylhexanoic acid amide, 3,5,5-trimethylhexanoic acid amide, 2-ethylhexanoic acid amide, 2-methylpentadecanoic acid amide, and 2-methylheptadecanoic acid amide.

[0047] The alkylene oxide having 2 to 4 carbon atoms includes ethylene oxide, propylene oxide and butylene oxide. Among them, from the viewpoint of dispersibility, it is preferred that the alkylene oxide unit is mainly composed, and the content (mol %) thereof is preferably 50 to 100, more preferably 60 to 100, and particularly preferably 80 to 100 relative to the total molar number of the alkylene oxide unit.

[0048] The number of moles of the alkylene oxide (C2-4) added is preferably an integer of 3 to 50, more preferably an integer of 5 to 45, and particularly preferably an integer of 9 to 40, relative to 1 mol of the active hydrogen compound. Within this range, dispersibility becomes more favorable.

[0049] The alkylene oxide adducts (B) of active hydrogen compounds can be obtained by a known alkylene oxide addition reaction or can be purchased from the market. Examples of trade names include EMULMIN series (alkylene oxide adducts of alcohols, Sanyo Chemical Industries, Ltd., “EMULMIN” is a registered trademark of the company), SANNONIC series (alkylene oxide adducts of alcohols, Sanyo Chemical Industries, Ltd., “SANNONIC” is a registered trademark of the company), NAROACTY series (alkylene oxide adducts of alcohols, Sanyo Chemical Industries, Ltd., “NAROACTY” is a registered trademark of the company), PUREMEEL series (alkylene oxide adducts of amines, Sanyo Chemical Industries, Ltd., “PUREMEEL” is a registered trademark of the company), IONE T series (alkylene oxide adducts of carboxylic acids, Sanyo Chemical Industries, Ltd., "IONET" is a registered trademark of the company), BLAUNON series (alkylene oxide adducts of alcohols, amines or amides, Aoki Oil & Fats Industries, Ltd., "BLAUNON" is a registered trademark of the company), FINESURF series (alkylene oxide adducts of alcohols, Aoki Oil & Fats Industries, Ltd., "FINESURF" is a registered trademark of the company), SAFETYCUT series (alkylene oxide adducts of alcohols, Aoki Oil & Fats Industries, Ltd.), WONDERSURF series (alkylene oxide adducts of alcohols, Aoki Oil & Fats Industries, Ltd., "WONDERSURF" is a registered trademark of the company), and nonionic series (alkylene oxide adducts of alcohols or carboxylic acids, NOF Corporation), etc.

[0050] The weight ratio (A:B) of the styrene-maleic acid organic ammonium salt copolymer (A) to the polyoxyalkylene compound (B) is preferably 10:90 to 90:10, more preferably 20:80 to 80:20, and particularly preferably 25:75 to 75:25. Within this range, dispersibility and water resistance become more favorable.

[0051] The dispersant of the present invention consists only of the styrene-maleic acid organic ammonium salt copolymer (A) and the alkylene oxide adduct of the active hydrogen compound (B), but may contain additives (defoaming agent, viscoelasticity regulator, wetting agent, film formation regulator, etc.) and / or solvents within a range that does not hinder the effects of the present invention.

[0052] Examples of defoaming agents include SN Defoamer 399, SN Defoamer 1311, and SN Defoamer 1315 (San Nopco Co., Ltd.); examples of viscoelasticity regulators include SN THICKNER 612, SN THICKNER 621N, SN THICKNER 617, and SN THICKNER 618 (San Nopco Co., Ltd.); examples of wetting agents include SN WET 125, SN WET 126, SN WET 366, SN WET S, SN WET FST2, SN WET L, SN WET 996, SN WET 980, and SN WET 984 (San Nopco Co., Ltd.); and examples of film-forming regulators include KYOWANOL M (KHNeochem Co., Ltd.; “KYOWANOL” is a registered trademark of the company). Examples of the solvent include water, ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, and polyethylene glycol monobutyl ether.

[0053] For the dispersant of the present invention, as long as the styrene-maleic acid organic ammonium salt copolymer (A) and the alkylene oxide adduct (B) of the active hydrogen compound are uniformly mixed, there is no limitation on the preparation method, and even if additives and / or solvents are contained, as long as they are uniformly mixed. From the viewpoint of easy manufacturability, it is preferred to use a solvent for manufacture. In addition, heating and cooling may also be performed during manufacture. It should be noted that when the active hydrogen compound is an amine having a branched alkyl group, when the styrene-maleic acid organic ammonium salt copolymer (A) and the alkylene oxide adduct (B) of the active hydrogen compound are mixed (the same after mixing), between the organic amine forming the salt of the styrene-maleic acid organic ammonium salt copolymer (A) and the alkylene oxide adduct (B), part or all of them may be salt-exchanged.

[0054] The dispersant of the present invention is suitable for use as a water-based coating agent (water-based paint and water-based ink, etc.). When used in a water-based coating agent, the content (weight %) of the dispersant is preferably 0.01 to 10, more preferably 0.05 to 5, based on the weight of the water-based coating agent. Within this range, more excellent dispersibility is exhibited.

[0055] The water-based coating agent preferably contains a water-based resin (emulsion or dispersion), a pigment, water, and additives as needed.

[0056] Examples of the water-based resin include acrylic resins, vinyl acetate resins, vinyl chloride resins, acrylate styrene resins, silicone resins, urethane resins, epoxy resins, and fluororesins, etc. Among them, acrylic resins, acrylate styrene resins, and epoxy resins are preferred.

[0057] Examples of pigments include inorganic pigments (calcium carbonate, titanium oxide, satin white, barium sulfate, talc, zinc oxide, gypsum, silica, ferrite, etc.) and organic pigments (carbon black, phthalocyanine blue, quinacridone red, isoindoline yellow, etc.). Examples of additives include defoamers, dispersants (excluding the dispersant of the present invention), leveling agents, wetting agents, and viscoelasticity regulators.

[0058] The water-based coating composition of the present invention can be prepared by using the above-mentioned dispersant, pigment, water and additives used as needed to prepare a water-based dispersion (grinding process), and then uniformly mixing the water-based dispersion, water-based resin and additives used as needed (paint mixing process). It should be noted that the above-mentioned dispersant can also be added in the paint mixing process. In addition, the above-mentioned dispersant, water-based resin, etc. can also be used after being diluted with a solvent in advance.

[0059] The dispersant of the present invention can be used not only in water-based coating agents but also in water-based pigment pastes, water-based ceramic slurries, and the like.

[0060] Example

[0061] Hereinafter, "part" means part by weight, and "%" means % by weight unless otherwise specified.

[0062] <Production Example 1>

[0063] 600 parts of water, 226 parts of styrene-maleic anhydride resin (1: XIRANE 1000, weight average molecular weight 5000, styrene 50 mol%, maleic anhydride 50 mol%, POLYSCOPE POLYMERS BV) and 174 parts of organic amine (1: 2-amino-2-methyl-1-propanol, Tokyo Chemical Industry Co., Ltd.) were stirred at about 25°C, then heated to 100°C under reflux conditions and stirred at 100°C for 24 hours. Thereafter, the mixture was cooled to about 25°C to obtain a 40% aqueous solution (yellow liquid) of styrene-maleic acid organic ammonium salt copolymer (A1: weight average molecular weight 6,000).

[0064] In addition, the weight average molecular weight (Mw) is measured by gel permeation chromatography (GPC) under the above-mentioned conditions (the same shall apply hereinafter).

[0065] <Production Example 2>

[0066] A 40% aqueous solution (yellow liquid) of a styrene-maleic anhydride organic ammonium salt copolymer (A2: weight average molecular weight 6,000) was obtained in the same manner as in Production Example 1, except that "226 parts of styrene-maleic anhydride resin (1)" was changed to "175 parts of styrene-maleic anhydride resin (1)" and "174 parts of organic amine (1)" was changed to "225 parts of organic amine (2: triethanolamine, Tokyo Chemical Industry Co., Ltd.)".

[0067] <Production Example 3>

[0068] 600 parts of water, 250 parts of styrene-maleic anhydride resin (2: XIRANE 2000, weight average molecular weight 6500, styrene 67 mol%, maleic anhydride 33 mol%, POLYSCOPE POLYMERS BV) and 150 parts of organic amine (3: diethanolamine, Tokyo Chemical Industry Co., Ltd.) were stirred at about 25°C, then heated to 100°C under reflux conditions and stirred at 100°C for 24 hours. Thereafter, the mixture was cooled to about 25°C to obtain a 40% aqueous solution (yellow liquid) of styrene-maleic acid ammonium salt copolymer (A3: weight average molecular weight 8,000).

[0069] <Production Example 4>

[0070] 104 parts (1 mol) of styrene and 98 parts (1 mol) of maleic anhydride were dissolved in 200 parts of methyl ethyl ketone to prepare a monomer solution, and 0.8 parts (3.5×10 -3 mol parts) was dissolved in 100 parts of methyl ethyl ketone to prepare an initiator solution.

[0071] While stirring 478 parts of methyl ethyl ketone at 80° C., the monomer solution and the initiator solution were added dropwise over 3 hours, and the reaction was continued at 80° C. for 3 hours after the addition was completed. The methyl ethyl ketone was then distilled off to obtain a styrene-maleic anhydride copolymer (3: yellowish brown solid, styrene 50 mol%, maleic anhydride 50 mol%, weight average molecular weight 8,000).

[0072] A 40% aqueous solution (yellow liquid) of a styrene-maleic acid organic ammonium salt copolymer (A4: weight average molecular weight 10,000) was obtained in the same manner as in Production Example 1 except that the styrene-maleic anhydride resin (1) was replaced with the styrene-maleic anhydride copolymer (3).

[0073] <Production Example 5>

[0074] In addition to the addition of an oil-soluble azo polymerization initiator (V-601, Wako Pure Chemical Industries, Ltd., Fujifilm) from 0.8 parts (3.5 × 10-3 molar parts) was changed to 0.5 parts (2.2×10 -3 A styrene-maleic anhydride copolymer (4: yellow solid, styrene 50 mol%, maleic anhydride 50 mol%, weight average molecular weight 10,000) was obtained in the same manner as in Production Example 4 except that the above conditions were 50 mol%.

[0075] A 40% aqueous solution of a styrene-maleic acid organic ammonium salt copolymer (A5: weight average molecular weight 12,000) was obtained in the same manner as in Production Example 1 except that the “styrene-maleic anhydride resin (1)” was replaced with the “styrene-maleic anhydride resin (4)”.

[0076] <Production Example 6>

[0077] Alcohol (1: Fine Oxocol 180, 2-(1,3,3-trimethylbutyl)-5,7,7-trimethyloctanol, hydroxyl value 207 mgKOH / g, Nissan Chemical Co., Ltd., "Fine Oxocol" is KH A registered trademark of Neochem Co., Ltd.}271 parts (1 mole part), heated to 100°C while stirring, pressurized to 0.2 MPa in gauge pressure using nitrogen, vented to 0.1 MPa, and repeated this operation 3 times (hereinafter, the operation using nitrogen is referred to as "nitrogen replacement"). Thereafter, 1762 parts (40 mole parts) of ethylene oxide (EO) were added dropwise at the same temperature over 3 hours, and stirring was continued at the same temperature for 1 hour, and further stirred at the same temperature for 2 hours to obtain an alkylene oxide adduct of an active hydrogen compound (B1: 2-(1,3,3-trimethylbutyl)-5,7,7-trimethyloctanol / EO 40 mole adduct).

[0078] <Production Example 7>

[0079] An alkylene oxide adduct of an active hydrogen compound (B2: branched octadecanol / EO40 molar adduct) was obtained in the same manner as in Preparation Example 6 except that 271 parts (1 molar part) of alcohol (1) was replaced with 268 parts (1 molar part) of alcohol (2: Fine Oxocol 180T, a mixture of 2-octyldecanol and 2-hexyldodecanol (hereinafter referred to as branched octadecanol), hydroxyl value 209 mgKOH / g, Nissan Chemical Co., Ltd.).

[0080] <Production Example 8>

[0081] Into a pressure-resistant reaction vessel, 144 parts (1 molar part) of alcohol (3: 3,5,5-trimethyl-1-hexanol, hydroxyl value 389 mgKOH / g, Tokyo Chemical Industry Co., Ltd.) were added, and the temperature was raised to 100°C while stirring. After nitrogen substitution, 352 parts (8 molar parts) of ethylene oxide (EO) were added dropwise over 2 hours at the same temperature, and stirring was continued for further 1 hour at the same temperature. Then, 116 parts (2 molar parts) of propylene oxide (PO) were added dropwise over 2 hours, and stirring was continued for further 2 hours at the same temperature to obtain an alkylene oxide adduct of an active hydrogen compound (B3: 3,5,5-trimethyl-1-hexanol / EO 8 mole / PO 2 mole block adduct).

[0082] <Example 1>

[0083] 100 parts of a 40% aqueous solution of the styrene-maleic acid organic ammonium salt copolymer (A1) prepared in Preparation Example 1, 40 parts of the alkylene oxide adduct (B1) of the active hydrogen compound prepared in Preparation Example 6, and 126 parts of water were uniformly mixed to obtain a dispersant (1) of the present invention (30% aqueous solution, containing weight ratio (A1:B1) = 50:50).

[0084] <Example 2>

[0085] 100 parts of a 40% aqueous solution of the styrene-maleic acid organic ammonium salt copolymer (A1) prepared in Preparation Example 1, 40 parts of the alkylene oxide adduct (B2) of the active hydrogen compound prepared in Preparation Example 7, and 126 parts of water were uniformly mixed to obtain a dispersant (2) of the present invention (30% aqueous solution, containing weight ratio (A1:B2) = 50:50).

[0086] <Example 3>

[0087] 100 parts of a 40% aqueous solution of the styrene-maleic acid organic ammonium salt copolymer (A1) prepared in Preparation Example 1, 40 parts of the alkylene oxide adduct (B3) of the active hydrogen compound prepared in Preparation Example 8, and 126 parts of water were uniformly mixed to obtain a dispersant (3) of the present invention (30% aqueous solution, containing weight ratio (A1:B3) = 50:50).

[0088] <Example 4>

[0089] 100 parts of a 40% aqueous solution of the styrene-maleic acid organic ammonium salt copolymer (A2) prepared in Production Example 2, 40 parts of an alkylene oxide adduct of an active hydrogen compound (B4: BLAUNON EH-11, 2-ethylhexanol / EO11 molar adduct, Aoki Oil & Fats Industry Co., Ltd., "BLAUNON" is a registered trademark of the company) and 126 parts of water were uniformly mixed to obtain a dispersant (4) of the present invention (30% aqueous solution, containing weight ratio (A2:B4) = 50:50).

[0090] <Example 5>

[0091] 100 parts of a 40% aqueous solution of the styrene-maleic acid organic ammonium salt copolymer (A2) prepared in Production Example 2, 120 parts of an alkylene oxide adduct of an active hydrogen compound (B4) and 313 parts of water were uniformly mixed to obtain a dispersant (5) of the present invention (30% aqueous solution, containing a weight ratio of (A2:B4) = 25:75).

[0092] <Example 6>

[0093] 100 parts of a 40% aqueous solution of the styrene-maleic acid organic ammonium salt copolymer (A2) prepared in Production Example 2, 13 parts of an alkylene oxide adduct of an active hydrogen compound (B4) and 64 parts of water were uniformly mixed to obtain a dispersant (5) of the present invention (30% aqueous solution, containing a weight ratio of (A2:B4) = 75:25).

[0094] <Example 7>

[0095] 100 parts of a 40% aqueous solution of the styrene-maleic acid organic ammonium salt copolymer (A3) prepared in Production Example 3, 40 parts of an alkylene oxide adduct of an active hydrogen compound (B5: BLAUNONE H-30, 2-ethylhexanol / EO30 molar adduct, Aoki Oil & Fats Industry Co., Ltd., "BLAUNON" is a registered trademark of the company) and 126 parts of water are uniformly mixed to obtain a dispersant (7) of the present invention (30% aqueous solution, containing weight ratio (A3:B5) = 50:50).

[0096] <Example 8>

[0097] 100 parts of a 40% aqueous solution of the styrene-maleic acid organic ammonium salt copolymer (A4) prepared in Production Example 4, 40 parts of an alkylene oxide adduct of an active hydrogen compound (B6: FINESURF FO-160, isostearyl alcohol / EO16 molar adduct, Aoki Oil & Fats Industry Co., Ltd., "FINESURF" is a registered trademark of the company) and 126 parts of water were uniformly mixed to obtain a dispersant (8) of the present invention (30% aqueous solution, containing weight ratio (A4:B6) = 50:50).

[0098] <Example 9>

[0099] 100 parts of a 40% aqueous solution of the styrene-maleic acid organic ammonium salt copolymer (A5) prepared in Production Example 5, 40 parts of an alkylene oxide adduct of an active hydrogen compound (B7: SAFETYCUT ID-1087, isodecyl alcohol / EO9 molar adduct, Aoki Oil & Fats Industries Co., Ltd.) and 126 parts of water were uniformly mixed to obtain a dispersant (9) of the present invention (30% aqueous solution, containing weight ratio (A5:B7) = 50:50).

[0100] <Comparative Example>

[0101] Based on the description of the examples in Patent Document 1 (Japanese National Publication No. 2011-511142), a comparative wetting and dispersing agent (W&D1) was obtained.

[0102] <Evaluation 1> Dispersibility of titanium oxide slurry

[0103] While stirring 30 parts of water, 1 part of the evaluation sample (dispersant) and 0.1 part of the defoamer (SN Defoamer 399, San Nopco Co., Ltd.), 70 parts of titanium oxide (TIPAQUE PFC105, Ishihara Sangyo Co., Ltd., "TIPAQUE" is a registered trademark of the company) were slowly added, and after the addition was completed, it was further stirred for 5 minutes to prepare a dispersion slurry. Then, the dispersion slurry was allowed to stand in a 25°C water tank for 15 minutes, and the viscosity was measured using a TVB15 viscometer (Toki Sangyo Co., Ltd., 25°C, 60 rpm). Thereafter, 0.1 parts of the evaluation sample was added, mixed for 5 minutes, and the dispersion slurry was allowed to stand in a 25°C water tank for 15 minutes, and the viscosity was measured in the same manner. This operation was repeated until the slurry viscosity was 100 mPa·s or less. The addition amount was calculated from the total amount of the consumed evaluation sample (dispersant) (consumption of the evaluation sample × 100 / total amount of water and titanium oxide; %), and is shown in the following table. The smaller the added amount, the better the dispersibility.

[0104]

[0105] <Evaluation 2> Dispersibility and water resistance of acrylic styrene emulsion color paste

[0106] 1. Preparation of acrylic styrene emulsion color paste and coating sample (1)

[0107] 30 parts of carbon black (MA-8, Mitsubishi Chemical Corporation), 20 parts of an evaluation sample (dispersant), 35 parts of water and glass beads (2 mm in diameter) were added to a glass bottle and shaken for 180 minutes using a paint shaker to prepare a color paste. 20 parts of the color paste and 80 parts of an acrylic styrene emulsion (ACRONAL 7659, BASF, concentration 50 wt%, "ACRONAL" is a registered trademark of BASF Societas Europaea) were uniformly mixed to prepare a water-based coating composition (1; acrylic styrene emulsion color paste), which was then applied to a glass plate using a 6-mil applicator and dried at 40°C for 3 hours to prepare a coating sample (1).

[0108] 2. Dispersibility

[0109] The gloss value (60°) of the coated sample (1) was measured using a gloss meter and is shown in the following table. The larger the value, the better the dispersibility.

[0110]

[0111] 3. Water resistance

[0112] The coated samples (1) were immersed in water at 25° C. for 2 hours, and the appearance of the coating film was visually checked. As a result, the coating samples using the dispersants prepared in Examples 1 to 9 did not change before and after immersion in water, but the coating film of the coating sample using the dispersant prepared in the comparative example peeled off after immersion in water.

[0113] <Evaluation 3> Dispersibility and water resistance of acrylic emulsion coatings

[0114] 1. Preparation of acrylic emulsion coating and coating sample (2)

[0115] Using the raw material composition listed in Table 3, an Excel automatic homogenizer equipped with an impeller blade was used to grind and mix the raw materials to prepare a water-based coating composition (2; acrylic emulsion coating). Next, the water-based coating composition (2) was applied to a glass plate using a 6-mil applicator and dried at 25° C. for 24 hours to prepare a coating sample (2).

[0116]

[0117] ※1 Thickener, San Nopco Co., Ltd.

[0118] *2 Titanium dioxide, Ishihara Sangyo Co., Ltd., and "TIPAQUE" are registered trademarks of the company.

[0119] ※3 Defoaming agent, San Nopco Co., Ltd.

[0120] *4 Acrylic emulsion, BASF, and “ACRONAL” are registered trademarks of BASF Societas Europaea.

[0121] *5 Film-forming regulator, KH Neochem Co., Ltd., and "KYOWANOL" are registered trademarks of the company.

[0122] ※6 Thickener, San Nopco Co., Ltd.

[0123] ※7 Defoamer, San Nopco Co., Ltd.

[0124] 2. Dispersibility

[0125] 1) Dispersion based on gloss value

[0126] The gloss values ​​(60°) of the coated samples (2) were measured using a gloss meter and are shown in the following table. The larger the value, the better the dispersibility.

[0127]

[0128] 2) Dispersibility based on storage

[0129] 180 mL of the water-based coating composition (2) was added to a 200 mL glass bottle, and after being stored at 40° C. for 2 weeks, the appearance was visually checked. As a result, it was confirmed that the water-based coating composition using the dispersant prepared in Examples 1 to 9 did not change before and after storage, but the water-based coating composition using the dispersant prepared in the comparative example separated into an upper layer (transparent layer) and a lower layer after storage.

[0130] 3. Water resistance

[0131] After the coated samples (2) were immersed in water at 25° C. for 48 hours, the appearance of the coating film was visually checked. As a result, for the coated samples using the dispersants prepared in Examples 1 to 9, there was no change before and after immersion in water, but for the coated samples using the dispersants prepared in the comparative examples, the coating film peeled off after immersion in water.

[0132] <Evaluation 4> Dispersibility and water resistance of epoxy emulsion coating

[0133] 1. Preparation of epoxy emulsion coating

[0134] The base material was prepared by grinding and mixing using an Excel automatic homogenizer (Seiki Co., Ltd., Model ED) equipped with an impeller blade using the raw material composition in Table 5.

[0135] 84 parts of the base material and 1 6 parts of a curing agent (Beckopox EH 613w / 80WA, polyamine emulsion, Daicel-Allnex Co., Ltd., nonvolatile content 80%, amine value 230 mgKOH / g, "Beckopox" is a registered trademark of Allnex Germany Gesellschaft mit beschränkter Haftung) were mixed at 2000 rpm for 5 minutes at 15 to 25°C using an Excel automatic homogenizer equipped with an impeller blade to obtain a water-based coating composition (3; epoxy emulsion coating). Next, the water-based coating composition (3) was applied on a glass plate using a 6-mil applicator and dried at 25°C for 24 hours to prepare a coating sample (3).

[0136]

[0137] ※8 Thickener, San Nopco Co., Ltd.

[0138] ※9 Wetting agent, San Nopco Co., Ltd.

[0139] *10 Aqueous solvents, The Dow Chemical Company, and “DOWANOL” are registered trademarks of the company.

[0140] ※11 Talc, Nippon Talc Co., Ltd.

[0141] ※12 Titanium dioxide, Ishihara Sangyo Co., Ltd., and "TIPAQUE" are registered trademarks of the company.

[0142] ※13 Zinc phosphate, Toho Pigment Industry Co., Ltd., and “EXPERT” are registered trademarks of the company.

[0143] ※14 Water-based epoxy resin, Daicel-Allnex Co., Ltd., solid content 53%, epoxy equivalent per unit resin solid content 520 g / eq, "Beckopox" is a registered trademark of Allnex Germany Gesellschaft mit beschränkter Haftung.

[0144] 2. Dispersibility

[0145] The gloss values ​​(60°) of the coated samples (3) were measured using a gloss meter and are shown in the following table. The larger the value, the better the dispersibility.

[0146]

[0147] 3. Water resistance

[0148] The coated samples (3) were immersed in water at 40° C. for 72 hours, and the appearance of the coating film was visually checked. As a result, the coating samples using the dispersants prepared in Examples 1 to 9 showed no change before and after immersion in water, but the coating samples using the dispersants prepared in the comparative examples showed swelling of the coating film after immersion in water.

[0149] The dispersant of the present invention has superior dispersibility compared to comparative dispersants, and the water-based coating composition using the dispersant of the present invention has superior water resistance compared to water-based coating compositions using comparative dispersants, and the appearance of the coating film obtained by applying the water-based coating composition is not impaired.

Claims

1. A dispersant, characterized in that: The invention relates to a styrene-maleic acid organic ammonium salt copolymer A and an alkylene oxide adduct B of at least one active hydrogen compound selected from alcohols, carboxylic acids, amines and amides, wherein the active hydrogen compound has 4 to 18 carbon atoms, the alkylene oxide has 2 to 4 carbon atoms, and the addition mole number is 3 to 50 moles. The active hydrogen compound has a branched alkyl chain having 4 to 18 carbon atoms.

2. The dispersant according to claim 1, wherein The constituent molar ratio of the styrene unit s to the maleic acid ammonium salt unit m constituting the styrene-maleic acid organic ammonium salt copolymer, ie, s:m, is 80:20 to 40:

60.

3. The dispersant according to claim 1 or 2, wherein The weight ratio of the styrene-maleic acid organic ammonium salt copolymer A to the alkylene oxide adduct of the active hydrogen compound B, namely A:B, is 10:90 to 90:

10.

4. The dispersant according to claim 1 or 2, wherein The alkylene oxide adduct B of the active hydrogen compound contains ethylene oxide units, and the content of the ethylene oxide units is 50 mol % to 100 mol % based on the total number of moles of the alkylene oxide units.

5. A water-based coating composition, characterized in that Contains a water-based coating agent and the dispersant according to claim 1 or 2.

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