Dispersants and aqueous coating compositions

Abstract

The purpose of the present invention is to provide a dispersant that exhibits exceptional dispersibility and that does not lower the water resistance of a resultant coating film even when added to a water-based coating agent. The present invention is a dispersant characterized by comprising: a styrene-maleic acid ammonium salt copolymer (A); and an alkylene oxide (C2-4; number of added moles: 10-100 mol) adduct (B) of at least one active hydrogen compound (C1-22) selected from the group consisting of alcohols, carboxylic acids, amines, and amides. The constituent molar ratio (s:m) of styrene units (s) and maleic acid ammonium salt units (m) constituting the styrene-maleic acid ammonium salt copolymer is preferably 80:20-40:60. The content weight ratio (A:B) of the styrene-maleic acid ammonium salt copolymer (A) and the polyoxyalkylene compound (B) is preferably 10:90-90:10.

Description

Technical Field

[0001] The present invention relates to a dispersant and an aqueous coating composition.

Background Art

[0002] As a dispersant, "a mixture having a low volatile organic compound (VOC) content, I 10% to 80% by weight of at least 50% salified copolymer of at least one ethylenically unsaturated, phenyl group-containing monomer and at least one α,β-unsaturated monocarboxylic acid and / or at least one α,β-unsaturated dicarboxylic acid, and optionally derivatives thereof, II 1% to 30% by weight of at least one water-soluble linear polyether containing terminal OH groups and synthesized from ethylene oxide in an amount of at least 25 mol%, III 5% to 80% by weight of at least one esterification product of an aliphatic dicarboxylic acid and at least one water-soluble polyether of component II which preferably has a number average molecular weight of ≦2000 g / mol, or of a mixture of polyethers comprising at least one water-soluble polyether of component II which preferably has a number average molecular weight of ≦2000 g / mol, IV 3% to 80% by weight of at least one star polymer obtainable by esterifying at least one aliphatic carboxylic acid containing 3 to 5 carboxyl groups with at least one water-soluble polyether of component II which preferably has a number average molecular weight of ≦2000 g / mol, or with a mixture of polyethers containing at least one water-soluble polyether of component II which preferably has a number average molecular weight of ≦2000 g / mol, the sum of the weight percentages of components I to IV must always be 100% by weight, and the weight percentages of components I to IV are in each case based on the total weight of components I to IV (Claim 1)"; "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"; From the group comprising "styrene, benzyl (meth)acrylate, and phenylacrylate (the phenyl radical may be substituted one to four times in some cases)" The mixture according to claim 5 (claim 6), characterized in that at least one selected monomer, preferably optionally substituted styrene, is used as the ethylenically unsaturated, phenyl group-containing monomer; "A mixture according to claim 5 or 6 (claim 7), characterized in that acrylic acid or methacrylic acid is used as an α,β-unsaturated monocarboxylic acid and at least one dicarboxylic acid (selected from the group including maleic acid, fumaric acid, itaconic acid and / or maleic anhydride), and optionally as a derivative thereof, preferably as an ester or amide, and at least one C1-C6 alkyl acrylate and / or C1-C6 alkyl methacrylate is used as an α,β-unsaturated dicarboxylic acid and / or its cyclic anhydride"; Furthermore, the use described in claim 21 or 22 for dispersing pigments (claim 23) is known (Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2011-511142 (Pamphlet WO2009 / 098025) [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Conventional dispersants may not disperse pigments sufficiently, and there is a problem that the water resistance of coating films obtained from aqueous coating compositions to which they are added decreases. The present invention aims to provide a dispersant that exhibits excellent dispersibility and does not reduce the water resistance of the resulting coating film when added to an aqueous coating agent. [Means for solving the problem]

[0005] The features of the dispersant of the present invention are a styrene-ammonium maleate copolymer (A) and, Monools and monoamines At least one active hydrogen compound selected from the group consisting of (number of carbon atoms) 8 Alkylene oxides (2 carbon atoms) ~22) 3 Number of moles added 30~60 It consists of a molar adduct (B), The main point is that the weight ratio (A:B) of the styrene-ammonium maleate copolymer (A) and the alkylene oxide adduct of the active hydrogen compound (B) is 25:75 to 75:25.

[0006] The main feature of the aqueous coating composition of the present invention is that it contains an aqueous coating agent and the above-mentioned dispersant. [Effects of the Invention]

[0007] The dispersant of the present invention exhibits excellent dispersibility and does not reduce the water resistance of the coating film obtained from the aqueous coating composition to which it is added.

[0008] Since the aqueous coating composition of the present invention contains the above-mentioned dispersant, it exhibits excellent dispersibility and yields a coating film with excellent water resistance. [Modes for carrying out the invention]

[0009] <Styrene-ammonium maleate copolymer (A)> The styrene-ammonium maleate copolymer (A) is not limited as long as it is a copolymer having styrene units (s) and ammonium maleate units (m) as constituent units, and copolymers produced by known methods can be used. For example, a copolymer obtained by hydrolyzing a styrene-maleic anhydride copolymer and neutralizing it with ammonia can be used.

[0010] Styrene-maleic anhydride copolymers can be manufactured by known methods and are also readily available on the market. Examples include XIRANE 1000 (styrene-maleic anhydride resin, weight-average molecular weight 5000, 50 mol% styrene, 50 mol% maleic anhydride, POLYSCOPE POLYMERS BV), XIRANE 2000 (styrene-maleic anhydride resin, weight-average molecular weight 6500, 67 mol% styrene, 33 mol% maleic anhydride, POLYSCOPE POLYMERS BV), XIRANE 3000 (styrene-maleic anhydride resin, weight-average molecular weight 10000, 75 mol% styrene, 25 mol% maleic anhydride, POLYSCOPE POLYMERS BV), and XIRANE 4000 (styrene-maleic anhydride resin, weight-average molecular weight 10000, 80 mol% styrene, 20 mol% maleic anhydride, POLYSCOPE POLYMERS BV).

[0011] The molar ratio (s:m) of styrene units (s) to ammonium maleate units (m) constituting the styrene-ammonium maleate 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.

[0012] The weight-average molecular weight (Mw) of the styrene-ammonium maleate 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 are further improved.

[0013] The weight average molecular weight (Mw) can be measured by gel permeation chromatography (GPC), for example, under the following conditions.

[0014] Measuring device: HLC-8420GPC (Tosoh Corporation; "HLC" is a registered trademark of the company) Column: TSKgel guard column α, TSKgel α6000, TSKgel α4000 (Tosoh Corporation; "TSKgel" is a registered trademark of the company) connected in series Detector: RI (differential refractometer) Data processing: ECOSEC Elite-WS (Tosoh Corporation; "ECOSEC" is a registered trademark of the company) Column temperature: 40°C Solvent: methanol:ion-exchanged water:sodium acetate = 800:1200:15 (weight ratio) Flow rate: 0.8 ml / min Standard substance: TSKgel standard polyethylene oxide (Tosoh Corporation; "TSKgel" is a registered trademark of the company) Sample: 0.4 wt% eluent solution

[0015] <Alkylene oxide adduct of active hydrogen compound (B)> The active hydrogen compound having 1 to 22 carbon atoms is not particularly limited as long as it is at least one selected from the group consisting of alcohols, carboxylic acids, amines and amides, and can chemically react with an alkylene oxide having 2 to 4 carbon atoms to form the alkylene oxide adduct of an active hydrogen compound.

[0016] Alcohols include monools, and linear primary alcohols (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, 1-tetradecanol, 1-pentadecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol, 1-octadecanol). Tadenol, 1-nonadecanol and 1-docosanol, etc.); Cyclodecanol, cyclododecanol and cyclopentadecanol, etc.; 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 (e.g., ethyl-4-undecanol); and 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-hex Examples include sanol, 2,2,4-trimethyl-1-hexanol, 3,5,5-trimethyl-1-hexanol, isononanol, isodecanol, 2-methyl-1-undecanol, 12-methyl-1-tridecanol, isotridecyl alcohol, 2-hexyl-1-decanol, isohexadecanol, 2-octyl-1-decanol, 2-hexyl-1-undecanol, isooctadecanol, and isoeicosanol, etc.

[0017] Examples of carboxylic acids include monocarboxylic acids, such as linear carboxylic acids (acetic acid, dodecanoic acid, octadecanoic acid, and octadecenoic acid); and branched carboxylic acids (2,2-dimethylpropanoic acid, 2-methylbutanoic 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, 2-methylheptadecanoic acid, and isoeicosanoic acid).

[0018] Examples of amines include monoamines, such as linear amines (dodecylamine, 1-amino-3-undecanoxypropane, hexylamine, octadecylamine, octadecenylamine, and docosylamine, etc.) and cyclic amines (cyclohexylamine, etc.).

[0019] Amides include monoamides, such as dodecanoic acid amide, octadecanoic acid amide, and octadecenoic acid amide.

[0020] Alkylene oxides having 2 to 4 carbon atoms include ethylene oxide, propylene oxide, and butylene oxide. Of these, from the viewpoint of dispersibility, it is preferable that ethylene oxide units are predominantly present, and the content (mol%) of ethylene oxide units is preferably 50 to 100, more preferably 60 to 100, and particularly preferably 80 to 100, relative to the total number of moles of alkylene oxide units.

[0021] The number of moles of alkylene oxide (with 2 to 4 carbon atoms) added is preferably an integer between 10 and 100, more preferably between 15 and 80, and particularly preferably between 30 and 60, per mole of the active hydrogen compound. Within this range, dispersibility is further improved.

[0022] Alkylene oxide adducts (B) of active hydrogen compounds can be obtained by known alkylene oxide addition reactions, as well as from the market. Trade names include: Emarumin series (alkylene oxide adducts of alcohols, Sanyo Chemical Industries, Ltd., "Emarumin" is a registered trademark of the company), Sunnonic series (alkylene oxide adducts of alcohols, Sanyo Chemical Industries, Ltd., "Sunnonic" 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), Puremeal series (alkylene oxide adducts of amines, Sanyo Chemical Industries, Ltd., "Puremeal" is a registered trademark of the company), and Ionet series (alkylene oxide adducts of carboxylic acids). Examples include alkylene oxide adducts (Sanyo Chemical Industries, Ltd., "Ionet" is a registered trademark of the company), the Brownon series (alkylene oxide adducts of alcohols, amines, or amides, Aoki Oil & Fat Co., Ltd., "Brownon" is a registered trademark of the company), the Nonion series (alkylene oxide adducts of alcohols or carboxylic acids, NOF Corporation), the Naimine series (alkylene oxide adducts of amines, NOF Corporation, "Naimine" is a registered trademark of the company), the Naimid series (alkylene oxide adducts of amides, NOF Corporation, "Naimid" is a registered trademark of the company), and the Softanol series (alkylene oxide adducts of linear secondary alcohols with 12 to 14 carbon atoms, Nippon Shokubai Co., Ltd., "Softanol" is a registered trademark of the company).

[0023] The weight ratio (A:B) of the styrene-ammonium maleate 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 are further improved.

[0024] The dispersant of the present invention consists only of a styrene-ammonium maleate copolymer (A) and an alkylene oxide adduct of an active hydrogen compound (B), but it may contain additives (such as defoaming agents, viscoelastic modifiers, wetting agents, and film-forming modifiers) and / or solvents, as long as they do not impair the effects of the present invention.

[0025] Examples of defoaming agents include SN Deformer 399, 1311, and 1315 (Sunnopco Ltd.), examples of viscoelastic modifiers include SN Thickener 612, 621N, 617, and 618 (Sunnopco Ltd.), examples of wetting agents include SN Wet 125, 126, 366, S, FST2, L, 996, 980, and 984 (Sunnopco Ltd.), and examples of film-forming modifiers include Texanol (Eastman Chemical Company, "Texanol" is a registered trademark of Yoshimura Oil & Chemical Co., Ltd.). Examples of solvents 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.

[0026] The dispersant of the present invention is not limited in its manufacturing method as long as the styrene-ammonium maleate copolymer (A) and the alkylene oxide adduct of the active hydrogen compound (B) are uniformly mixed. Even if additives and / or solvents are included, it is sufficient as long as these are uniformly mixed. From the viewpoint of ease of manufacture, it is preferable to manufacture it using a solvent. Furthermore, the manufacturing process may involve heating and cooling.

[0027] The dispersant of the present invention is suitable for use with water-based coating agents (water-based paints and water-based inks, etc.). When applied to water-based coating agents, the dispersant content (by weight) is preferably 0.01 to 10, and more preferably 0.05 to 5, based on the weight of the water-based coating agent. Within this range, even better dispersibility is achieved.

[0028] The aqueous coating agent preferably contains an aqueous resin (emulsion or dispersion), a pigment, water, and optionally additives, etc.

[0029] Examples of the aqueous resin include acrylic resins, vinyl acetate resins, vinyl chloride resins, acrylic styrene resins, silicone resins, urethane resins, epoxy resins, fluororesins, and the like. Among these, acrylic resins, acrylic styrene resins, and epoxy resins are preferred.

[0030] 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 antifoaming agents, dispersants, leveling agents, wetting agents, viscoelasticity adjusting agents, and the like.

[0031] The aqueous coating composition of the present invention can be produced by preparing an aqueous dispersion using the above dispersant, pigment, water and optional additives (grinding step), then uniformly mixing the aqueous dispersion, aqueous resin and optional additives (letting down step). The above dispersant may also be added in the letting down step. Further, the above dispersant, aqueous resin, etc. may be used after being diluted with a solvent in advance.

[0032] The dispersant of the present invention can be applied to uses other than aqueous coating agents, and is also suitable for aqueous pigment pastes, aqueous ceramic slurries, and the like. EXAMPLES

[0033] Hereinafter, unless otherwise specified, "parts" means parts by weight, and "%" means % by weight.

[0034] <Production Example 1> 469 parts of water, 349 parts of styrene-maleic anhydride resin (1: XIRANE 1000, weight-average molecular weight 5000, 50 mol% styrene, 50 mol% maleic anhydride, POLYSCOPE POLYMERS BV), and 182 parts of 28% aqueous ammonia solution (Nacalai Tesque Co., Ltd.) were uniformly mixed at approximately 25°C. The mixture was then heated to 100°C under a sealed container and uniformly stirred at 100°C for 8 hours. After cooling to approximately 25°C, a 40% aqueous solution (yellow liquid) of styrene-ammonium maleate copolymer (A1: weight-average molecular weight 6000) was obtained.

[0035] The weight-average molecular weight (Mw) was measured by gel permeation chromatography (GPC) under the conditions described above (the same conditions apply hereafter).

[0036] <Manufacturing Example 2> 509 parts water, 365 parts styrene-maleic anhydride resin (2: XIRANE 2000, weight-average molecular weight 6500, styrene 67 mol%, maleic anhydride 33 mol%, POLYSCOPE POLYMERS BV), and 126 parts 28% aqueous ammonia solution (Nacalai Tesque Co., Ltd.) were uniformly mixed at approximately 25°C. The mixture was then heated to 100°C under a sealed container and uniformly stirred at 100°C for 8 hours. After cooling to approximately 25°C, a 40% aqueous solution (yellow liquid) of styrene-ammonium maleate copolymer (A2: weight-average molecular weight 8000) was obtained.

[0037] <Manufacturing Example 3> A monomer solution was prepared by dissolving 104 parts (1 mole) of styrene and 98 parts (1 mole) of maleic anhydride in 200 parts of methyl ethyl ketone, and then adding 0.8 parts (3.5 × 10) of an oil-soluble azo polymerization initiator (V-601, Wako Pure Chemical Industries, Ltd. Fujifilm Corporation). -3 An initiator solution was prepared by dissolving (molar portion) in 100 parts of methyl ethyl ketone. 478 parts of methyl ethyl ketone at 80°C were stirred, and the monomer solution and initiator solution were added dropwise over 3 hours. After the dropwise addition was complete, the reaction was continued at 80°C for another 3 hours. The methyl ethyl ketone was then removed by distillation to obtain a styrene-maleic anhydride copolymer (3: yellowish-brown solid, 50 mol% styrene, 50 mol% maleic anhydride).

[0038] A 40% aqueous solution (brown liquid) of styrene-maleic acid-ammonium salt copolymer (A3: 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 a styrene-maleic anhydride copolymer (3).

[0039] <Manufacturing Example 4> 0.8 parts (3.5 x 10) of oil-soluble azo polymerization initiator (V-601, Wako Pure Chemical Industries, Ltd. Fujifilm Corporation) -3 (moles) to 0.5 parts (2.2 × 10) -3 A styrene-maleic anhydride copolymer (4: yellowish-brown solid, 50 mol% styrene, 50 mol% maleic anhydride) was obtained in the same manner as in Production Example 3, except that the mole portion was changed.

[0040] A 40% aqueous solution of styrene-ammonium maleate copolymer (A4: weight-average molecular weight 12,000) was obtained in the same manner as in Production Example 1, except that styrene-maleic anhydride resin (1) was replaced with styrene-maleic anhydride resin (4).

[0041] <Manufacturing Example 5> 195 parts (1 mole) of alcohol (1: Calcol 2475, a mixed alcohol with 12-14 carbon atoms, hydroxyl value 288 mg KOH / g, Kao Corporation, "Calcol" is a registered trademark of the company) was added to a pressure-resistant reaction vessel, and the temperature was raised to 100°C while stirring. Using nitrogen gas, the mixture was pressurized to a gauge pressure of 0.2 MPa and then discharged to 0.1 MPa, a process that was repeated three times (hereinafter, this operation using nitrogen gas will be abbreviated as "nitrogen gas displacement"). Subsequently, at the same temperature, 1056 parts (24 moles) of ethylene oxide (EO) were added dropwise over 2 hours, and stirring was continued at the same temperature for another hour. Then, 336 parts (6 moles) of propylene oxide (PO) were added dropwise over 2 hours, and stirring was continued at the same temperature for another 2 hours to obtain an alkylene oxide adduct of an active hydrogen compound (B1: mixed alcohol with 12-14 carbon atoms / EO 24 moles / PO 6 moles block adduct).

[0042] <Manufacturing Example 6> Except for changing 195 parts (1 mole) of alcohol (1) to 260 parts (1 mole) of alcohol (2: Calcol 8665, a mixed alcohol with 16-18 carbon atoms, hydroxyl value 216 mg KOH / g, Kao Corporation, "Calcol" is a registered trademark of the company), the alkylene oxide adduct of the active hydrogen compound (B2: mixed alcohol with 16-18 carbon atoms / EO 48 moles / PO 12 mole block adduct) was obtained in the same manner as in Production Example 5, except that "adding 1056 parts (24 moles) of ethylene oxide (EO) dropwise over 2 hours" was changed to "adding 2112 parts (48 moles) of ethylene oxide (EO) dropwise over 4 hours", and "adding 336 parts (6 moles) of propylene oxide (PO) dropwise over 2 hours" was changed to "adding 672 parts (12 moles) of propylene oxide (PO) dropwise over 4 hours".

[0043] <Manufacturing Example 7> Except for changing 260 parts (1 mole) of alcohol (1) to 320 parts (1 mole) of alcohol (3: Calcol 220-80, a mixed alcohol with 18 and 22 carbon atoms, hydroxyl value 175 mg KOH / g, Kao Corporation, "Calcol" is a registered trademark of the company), the alkylene oxide adduct of the active hydrogen compound (B3: mixed alcohol with 18 and 22 carbon atoms / EO 48 moles / PO 12 mole block adduct) was obtained in the same manner as in Production Example 5, except that "adding 1056 parts (24 moles) of ethylene oxide (EO) dropwise over 2 hours" was changed to "adding 2112 parts (48 moles) of ethylene oxide (EO) dropwise over 4 hours", and "adding 336 parts (6 moles) of propylene oxide (PO) dropwise over 2 hours" was changed to "adding 672 parts (12 moles) of propylene oxide (PO) dropwise over 4 hours".

[0044] <Example 1> 100 parts of a 40% aqueous solution of the styrene-ammonium maleate copolymer (A1) prepared in Production Example 1, 13.3 parts of the alkylene oxide adduct of the active hydrogen compound (B1) prepared in Production Example 5, and 64.3 parts of water were uniformly mixed to obtain the dispersant (1) of the present invention (30% aqueous solution, weight ratio of A1:B1 = 75:25).

[0045] <Example 2> 100 parts of a 40% aqueous solution of the styrene-ammonium maleate copolymer (A1) prepared in Production Example 1, 13.3 parts of the alkylene oxide adduct of the active hydrogen compound (B2) prepared in Production Example 6, and 64.3 parts of water were uniformly mixed to obtain the dispersant (2) of the present invention (30% aqueous solution, weight ratio of A1:B2 = 75:25).

[0046] <Example 3> 100 parts of a 40% aqueous solution of the styrene-ammonium maleate copolymer (A1) prepared in Production Example 1, 40 parts of the alkylene oxide adduct of the active hydrogen compound (B2) prepared in Production Example 6, and 126 parts of water were uniformly mixed to obtain the dispersant (3) of the present invention (30% aqueous solution, weight ratio of (A1:B2) = 50:50).

[0047] <Example 4> 100 parts of a 40% aqueous solution of the styrene-ammonium maleate copolymer (A2) prepared in Production Example 2, 13.3 parts of the alkylene oxide adduct of the active hydrogen compound (B3) prepared in Production Example 7, and 64.3 parts of water were uniformly mixed to obtain the dispersant (4) of the present invention (30% aqueous solution, weight ratio of A2:B3 = 75:25).

[0048] <Example 5> 100 parts of a 40% aqueous solution of the styrene-ammonium maleate copolymer (A3) prepared in Production Example 3, 40 parts of an alkylene oxide adduct of an active hydrogen compound (B4: Brownon EH-11, 2-ethylhexyl alcohol / EO 11 molar adduct, Aoki Oil & Fat Co., Ltd., "Brownon" is a registered trademark of the same company) and 126 parts of water were uniformly mixed to obtain the dispersant (5) of the present invention (30% aqueous solution, weight ratio of A3:B4 = 50:50).

[0049] <Example 6> Fifty parts of a 40% aqueous solution of the styrene-ammonium maleate copolymer (A4) prepared in Production Example 4, sixty parts of an alkylene oxide adduct of an active hydrogen compound (B5: Brownon EH-30, 2-ethylhexyl alcohol / EO 30 molar adduct, Aoki Oil & Fat Co., Ltd., "Brownon" is a registered trademark of the same company) and 160 parts of water were uniformly mixed to obtain the dispersant (6) of the present invention (30% aqueous solution, weight ratio of A4:B5 = 25:75).

[0050] <Example 7> 100 parts of a 40% aqueous solution of the styrene-ammonium maleate copolymer (A1) prepared in Production Example 1, 40 parts of an alkylene oxide adduct of an active hydrogen compound (B6: Brownon EN-1530, oleyl alcohol / EO 30 molar adduct, Aoki Oil & Fat Co., Ltd., "Brownon" is a registered trademark of the same company) and 126 parts of water were uniformly mixed to obtain the dispersant (7) of the present invention (30% aqueous solution, weight ratio of A1:B6 = 50:50).

[0051] <Example 8> 100 parts of a 40% aqueous solution of the styrene-ammonium maleate copolymer (A1) prepared in Production Example 1, 40 parts of an alkylene oxide adduct of an active hydrogen compound (B7: Brownon CH-340, cetyl alcohol / EO 40 molar adduct, Aoki Oil & Fat Co., Ltd., "Brownon" is a registered trademark of the same company) and 126 parts of water were uniformly mixed to obtain the dispersant (8) of the present invention (30% aqueous solution, weight ratio of A1:B7 = 50:50).

[0052] <Example 9> 100 parts of a 40% aqueous solution of the styrene-ammonium maleate copolymer (A1) prepared in Production Example 1, 40 parts of an alkylene oxide adduct of an active hydrogen compound (B8: Brownon EN-1560, oleyl alcohol / EO 60 molar adduct, Aoki Oil & Fat Co., Ltd., "Brownon" is a registered trademark of the same company) and 126 parts of water were uniformly mixed to obtain the dispersant (9) of the present invention (30% aqueous solution, weight ratio of content (A1:B8) = 50:50).

[0053] <Example 10> 100 parts of a 40% aqueous solution of the styrene-ammonium maleate copolymer (A1) prepared in Production Example 1, 40 parts of an alkylene oxide adduct of an active hydrogen compound (B9: Softanol 300, a linear secondary alcohol with 12-14 carbon atoms / EO 30 molar adduct, Nippon Shokubai Co., Ltd., "Softanol" is a registered trademark of the same company) and 126 parts of water were uniformly mixed to obtain the dispersant (10) of the present invention (30% aqueous solution, weight ratio of content (A1:B9) = 50:50).

[0054] <Example 11> Fifty parts of a 40% aqueous solution of the styrene-ammonium maleate copolymer (A1) prepared in Production Example 1, sixty parts of an alkylene oxide adduct of an active hydrogen compound (B10: FineSurf NE-100, synthetic alcohol (12-13 carbon atoms) / EO 10 molar adduct, Aoki Oil & Fat Industry Co., Ltd., "FineSurf" is a registered trademark of the same company) and sixteen parts of water were uniformly mixed to obtain the dispersant (11) of the present invention (30% aqueous solution, weight ratio of content (A1:B10) = 25:75).

[0055] <Example 12> 100 parts of a 40% aqueous solution of the styrene-ammonium maleate copolymer (A1) prepared in Production Example 1, 13.3 parts of an alkylene oxide adduct of an active hydrogen compound (B11: Braunon L-210, laurylamine / EO 10 molar adduct, Aoki Oil & Fat Co., Ltd., "Braunon" is a registered trademark of the same company) and 64.3 parts of water were uniformly mixed to obtain the dispersant (12) of the present invention (30% aqueous solution, weight ratio of content (A1:B11) = 75:25).

[0056] <Example 13> 100 parts of a 40% aqueous solution of the styrene-ammonium maleate copolymer (A1) prepared in Production Example 1, 13.3 parts of an alkylene oxide adduct of an active hydrogen compound (B11: Brownon S-230, stearylamine / EO 30 molar adduct, Aoki Oil & Fat Co., Ltd., "Brownon" is a registered trademark of the same company) and 64.3 parts of water were uniformly mixed to obtain the dispersant (13) of the present invention (30% aqueous solution, weight ratio of content (A1:B11) = 75:25).

[0057] <Comparative Example> Based on the description of the examples in Patent Document 1 (Japanese Patent Publication No. 2011-511142), a comparative wetting and dispersing agent (W&D1) was obtained.

[0058] <Evaluation 1> Dispersibility of titanium dioxide slurry A dispersion slurry was prepared by gradually adding 70 parts of titanium dioxide (Typake R-930, Ishihara Sangyo Co., Ltd., "Typake" is a registered trademark of the company) while stirring 30 parts of water, 1 part of the evaluation sample (dispersant), and 0.1 parts of an antifoaming agent (SN Deformer 399, Sunopco Co., Ltd.). After the addition was completed, the mixture was stirred for another 5 minutes to prepare the dispersion slurry. The dispersion slurry was then left to stand in a 25°C water bath for 15 minutes, and its viscosity was measured using a TVB15 viscometer (Toki Sangyo Co., Ltd., 25°C, 60 rpm). Subsequently, 0.1 parts of the evaluation sample was added, mixed for 5 minutes, and then left to stand in a 25°C water bath for 15 minutes. This process of measuring viscosity was repeated until the slurry viscosity was 100 mPa·s or less. The amount added (amount of evaluation sample consumed × 100 / total amount of water and titanium dioxide; %) was calculated from the total amount of evaluation sample (dispersant) consumed and is shown in the table below. A smaller amount of added material indicates better dispersibility.

[0059] [Table 1]

[0060] <Evaluation 2> Dispersibility and water resistance of acrylic styrene emulsion color paste 1. Preparation of acrylic styrene emulsion color paste and coated sample (1) 30 parts carbon black (MA-100, Mitsubishi Chemical Corporation), 35 parts evaluation sample (dispersant), 35 parts water, and glass beads (2 mm in diameter) were placed in a glass bottle and shaken in a paint shaker for 60 minutes to prepare a color paste. Then, 20 parts of the color paste and 80 parts acrylic styrene emulsion (Acronal 295DN, BASF, concentration 50% by weight, BASF Aktiengesellschaft) were uniformly mixed to prepare a water-based coating composition (1; acrylic styrene emulsion color paste). This was then applied to a glass plate using a 6 mil applicator and dried at 40°C for 3 hours to prepare a coated sample (1).

[0061] 2.Dispersibility For each coated sample (1), the gloss value (60°) was measured using a gloss meter and is shown in the table below. A higher value indicates better dispersibility.

[0062] [Table 2]

[0063] 3.Water resistant Each coated sample (1) was immersed in water at 25°C for 2 hours, and the appearance of the coating film was visually inspected. As a result, there was no change in the coated samples using the dispersants prepared in Examples 1 to 13 before and after immersion in water, but the coating film peeled off the coated samples using the dispersants prepared in the comparative example after immersion in water.

[0064] <Evaluation 3> Dispersibility and water resistance of acrylic emulsion paint 1. Preparation of acrylic emulsion paint and coating sample (2) Using the raw material compositions listed in Table 3, a water-based coating composition (2; acrylic emulsion paint) was prepared by grinding and letting down using an Excel autohomogenizer equipped with an impeller-type blade. Subsequently, 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 coated sample (2).

[0065] [Table 3]

[0066] *1 Thickening agent, Sunopco Co., Ltd. *2 Titanium dioxide, Ishihara Sangyo Co., Ltd., and "Typeque" are registered trademarks of the company. *3 Antifoaming agent, Sunopco Co., Ltd. *4 Acrylic emulsion, DIC Corporation, and "Boncoat" are registered trademarks of the company. *5 Film-forming modifier, Eastman Chemical Company, and "Texanol" are registered trademarks of Yoshimura Oil & Chemical Co., Ltd. *6 Thickening agent, Sunopco Co., Ltd. *7 Antifoaming agent, Sunopco Co., Ltd.

[0067] 2.Dispersibility 1) Dispersion based on gross value For each of the coated samples (2), the gloss value (60°) was measured using a gloss meter and is shown in the table below. A higher value indicates better dispersibility.

[0068] [Table 4]

[0069] 2) Dispersion due to storage 180 mL of the aqueous coating composition (2) was placed in a 200 mL glass bottle and stored at 40°C for two weeks, after which the appearance was visually inspected. As a result, the aqueous coating compositions using the dispersants prepared in Examples 1 to 13 showed no change before and after storage, but the aqueous coating compositions using the dispersants prepared in the comparative examples showed separation into an upper layer (transparent layer) and a lower layer after storage.

[0070] 3.Water resistant Each of the coated samples (2) was immersed in water at 25°C for 48 hours, after which the appearance of the coating film was visually inspected. As a result, there was no change in the coated samples using the dispersants prepared in Examples 1 to 13 before and after immersion in water, but the coating film peeled off the coated samples using the dispersants prepared in the comparative example after immersion in water.

[0071] <Evaluation 4> Dispersibility and water resistance of epoxy emulsion paint 1. Preparation of epoxy emulsion paint The base was prepared by grinding and letting down the raw material composition shown in Table 5 using an Excel autohomogenizer (Nippon Seiki Co., Ltd., Model ED) equipped with an impeller-type blade. 84 parts of this base and 16 parts of a curing agent (jER Cure WD11M60, modified polyamidoamine, Mitsubishi Chemical Corporation, solids content 60%, active hydrogen equivalent per resin solids 540 g / eq, "jER" is a registered trademark of the company) were mixed in an Excel autohomogenizer equipped with an impeller-type blade at 15-25°C, 2000 rpm, for 5 minutes to obtain a water-based coating composition (3; epoxy emulsion paint). Subsequently, the water-based coating composition (3) was applied to a glass plate using a 6-mil applicator and dried at 25°C for 24 hours to prepare a coated sample (3).

[0072] [Table 5]

[0073] *8, 15 Thickening agent, Sunopco Co., Ltd. *9 Humectant, Sunopco Co., Ltd. *10 Water-based solvents, The Dow Chemical Company, and "Dawonol" are registered trademarks of the company. *11 Talc, Nippon Talc Co., Ltd. *12 Titanium dioxide, Ishihara Sangyo Co., Ltd., and "Typeque" are registered trademarks of the company. *13 Zinc phosphate, Toho Pigment Industry Co., Ltd., and "Expert" are registered trademarks of the company. *14 Water-based epoxy resin, Mitsubishi Chemical Corporation, solids content 55%, epoxy equivalent per resin solids 1018g / eq, "jER" is a registered trademark of the company.

[0074] 2.Dispersibility For each of the coated samples (3), the gloss value (60°) was measured using a gloss meter and is shown in the table below. A higher value indicates better dispersibility.

[0075] [Table 6]

[0076] 3.Water resistant Each of the coated samples (3) was immersed in 40°C water for 72 hours, after which the appearance of the coating film was visually inspected. As a result, there was no change in the coated samples using the dispersants prepared in Examples 1 to 13 before and after immersion in water, but blistering occurred in the coating film of the coated samples using the dispersants prepared in the comparative example after immersion in water.

[0077] The dispersant of the present invention exhibits superior dispersibility compared to comparative dispersants, and the aqueous coating composition using the dispersant of the present invention exhibits superior water resistance compared to the aqueous coating composition using comparative dispersants, and does not impair the appearance of the coating film obtained by applying the aqueous coating composition.

Claims

1. Styrene-ammonium maleate copolymer (A), It consists of an alkylene oxide adduct (B) of at least one active hydrogen compound (8-22 carbon atoms) selected from the group consisting of monools and monoamines (2-3 carbon atoms; 30-60 moles added), A dispersant for inorganic pigments or carbon black in an aqueous coating composition, characterized in that the weight ratio (A:B) of a styrene-ammonium maleate copolymer (A) and an alkylene oxide adduct of an active hydrogen compound (B) is 25:75 to 75:

25.

2. The dispersant according to claim 1, wherein the molar ratio (s:m) of styrene units (s) to ammonium maleate units (m) constituting the styrene-ammonium maleate copolymer is 80:20 to 40:

60.

3. 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 ethylene oxide units is 50 to 100 mol% of the total number of moles of alkylene oxide units.

4. A water-based coating composition characterized by containing a water-based coating agent and a dispersant as described in claim 1 or 2.

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